Science.gov

Sample records for modulating methicillin resistance

  1. Nuclease Modulates Biofilm Formation in Community-Associated Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Kiedrowski, Megan R.; Kavanaugh, Jeffrey S.; Malone, Cheryl L.; Mootz, Joe M.; Voyich, Jovanka M.; Smeltzer, Mark S.; Bayles, Kenneth W.; Horswill, Alexander R.

    2011-01-01

    Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging contributor to biofilm-related infections. We recently reported that strains lacking sigma factor B (sigB) in the USA300 lineage of CA-MRSA are unable to develop a biofilm. Interestingly, when spent media from a USA300 sigB mutant was incubated with other S. aureus strains, biofilm formation was inhibited. Following fractionation and mass spectrometry analysis, the major anti-biofilm factor identified in the spent media was secreted thermonuclease (Nuc). Considering reports that extracellular DNA (eDNA) is an important component of the biofilm matrix, we investigated the regulation and role of Nuc in USA300. The expression of the nuc gene was increased in a sigB mutant, repressed by glucose supplementation, and was unaffected by the agr quorum-sensing system. A FRET assay for Nuc activity was developed and confirmed the regulatory results. A USA300 nuc mutant was constructed and displayed an enhanced biofilm-forming capacity, and the nuc mutant also accumulated more high molecular weight eDNA than the WT and regulatory mutant strains. Inactivation of nuc in the USA300 sigB mutant background partially repaired the sigB biofilm-negative phenotype, suggesting that nuc expression contributes to the inability of the mutant to form biofilm. To test the generality of the nuc mutant biofilm phenotypes, the mutation was introduced into other S. aureus genetic backgrounds and similar increases in biofilm formation were observed. Finally, using multiple S. aureus strains and regulatory mutants, an inverse correlation between Nuc activity and biofilm formation was demonstrated. Altogether, our findings confirm the important role for eDNA in the S. aureus biofilm matrix and indicates Nuc is a regulator of biofilm formation. PMID:22096493

  2. Methicillin resistant Staphylococcus aureus meningitis

    PubMed Central

    Pereira, Noella Maria Delia; Shah, Ira; Ohri, Alpana; Shah, Forum

    2015-01-01

    Methicillin resistant Staphylococcus aureus (MRSA) meningitis is rarely known to occur in children. We report an 11-year-old girl with fever, headache and vomiting, right hemiparesis with left-sided upper motor neuron facial nerve palsy and bladder incontinence. On investigation, she was found to have MRSA meningitis with an acute left thalamo-corpuscular infarct. She was treated with vancomycin, linezolid and rifampicin. She recovered successfully with residual right-sided lower limb monoparesis. MRSA meningitis is rare but can occur in children. PMID:26609421

  3. Rhodomyrtone Modulates Innate Immune Responses of THP-1 Monocytes to Assist in Clearing Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Srisuwan, Sutthirat; Tongtawe, Pongsri; Srimanote, Potjanee; Voravuthikunchai, Supayang Piyawan

    2014-01-01

    Background The increasing resistance of Staphylococcus aureus to conventional antibiotics poses a major health problem. Moreover, S. aureus can survive within phagocytes, thus evading some antibiotics and the innate immune response. Rhodomyrtone, a bioactive compound from the leaves of Rhodomyrtus tomentosa, possesses potent antibacterial activity against methicillin-resistant S. aureus (MRSA). This study was to investigate the immunomodulatory effects of rhodomyrtone on THP-1 monocytes in response to MRSA. Methods THP-1 monocytes were stimulated with heat-killed MRSA, followed by treatment with rhodomyrtone. The cell pellets were prepared to detect pro-inflammatory molecules using real-time PCR. The supernatants were collected to assess nitric oxide production using Griess assay. Assays for phagocytosis and bacterial killing by THP-1 monocytes were performed to determine if they were affected by rhodomyrtone. Results Expression of pro-inflammatory molecules including IL-1β, TNF-α, IL-6, and iNOS was enhanced in THP-1 monocytes stimulated with high doses of heat-killed MRSA (108 to 109 cfu/ml). In contrast, monocytes stimulated with MRSA at lower doses (106 to 107 cfu/ml) did not induce the expression of these cytokines. However, rhodomyrtone significantly increased the expression of pro-inflammatory mediators, IL-6 and iNOS in monocytes stimulated with heat-killed MRSA at low doses, and displayed some anti-inflammatory activity by reducing TNF-α expression in monocytes stimulated with heat-killed MRSA at high doses. Treatment with rhodomyrtone also significantly up-regulated the expression of the key pattern recognition receptors, TLR2 and CD14, in THP-1 monocytes stimulated with heat-killed MRSA at 106 to 109 cfu/ml, while heat-killed MRSA alone did not induce the expression of these molecules. The ability of rhodomyrtone to eliminate MRSA from the monocytes was observed within 24 h after treatment. Conclusion Rhodomyrtone enhanced the expression of pattern

  4. Detection of methicillin-resistant Staphylococcus epidermidis.

    PubMed

    Woods, G L; Hall, G S; Rutherford, I; Pratt, K J; Knapp, C C

    1986-09-01

    To determine whether methods suggested for detecting methicillin-resistant Staphylococcus aureus apply equally to methicillin-resistant Staphylococcus epidermidis, 135 S. epidermidis isolates were tested by the Vitek AMS gram-positive susceptibility card (Vitek Systems, Inc., Hazelwood, Mo.) and by modifications of agar screen, disk diffusion, and microdilution methods. Modifications included 24- versus 48-h incubation, unsupplemented versus 2% NaCl-supplemented broth, and standard versus direct inoculum. At 24 h, the highest number of resistant strains, 59, was detected by oxacillin (1 microgram) disk diffusion. At 48 h, three additional strains were judged resistant. With one exception, results for oxacillin disk diffusion and agar screen were equivalent at 24 and 48 h. Vitek detected 50 resistant strains. Significantly fewer resistant strains were detected at 24 h by methicillin disk diffusion (5 micrograms) and methicillin microdilution with 2% NaCl. For oxacillin microdilution, neither 2% NaCl supplementation nor the method of inoculum preparation significantly affected the results. Oxacillin microdilution with cation- rather than non-cation-supplemented broth detected significantly fewer (n = 33) resistant strains at 24 h; 51 were resistant at 48 h. To detect methicillin-resistant S. epidermidis, a direct inoculum with either 24-h oxacillin disk diffusion and reincubation of intermediate strains for an additional 24 h or 24-h oxacillin agar screen and reincubation of strains with no growth for a total of 48 h is recommended.

  5. Detection of methicillin-resistant Staphylococcus epidermidis.

    PubMed

    Woods, G L; Hall, G S; Rutherford, I; Pratt, K J; Knapp, C C

    1986-09-01

    To determine whether methods suggested for detecting methicillin-resistant Staphylococcus aureus apply equally to methicillin-resistant Staphylococcus epidermidis, 135 S. epidermidis isolates were tested by the Vitek AMS gram-positive susceptibility card (Vitek Systems, Inc., Hazelwood, Mo.) and by modifications of agar screen, disk diffusion, and microdilution methods. Modifications included 24- versus 48-h incubation, unsupplemented versus 2% NaCl-supplemented broth, and standard versus direct inoculum. At 24 h, the highest number of resistant strains, 59, was detected by oxacillin (1 microgram) disk diffusion. At 48 h, three additional strains were judged resistant. With one exception, results for oxacillin disk diffusion and agar screen were equivalent at 24 and 48 h. Vitek detected 50 resistant strains. Significantly fewer resistant strains were detected at 24 h by methicillin disk diffusion (5 micrograms) and methicillin microdilution with 2% NaCl. For oxacillin microdilution, neither 2% NaCl supplementation nor the method of inoculum preparation significantly affected the results. Oxacillin microdilution with cation- rather than non-cation-supplemented broth detected significantly fewer (n = 33) resistant strains at 24 h; 51 were resistant at 48 h. To detect methicillin-resistant S. epidermidis, a direct inoculum with either 24-h oxacillin disk diffusion and reincubation of intermediate strains for an additional 24 h or 24-h oxacillin agar screen and reincubation of strains with no growth for a total of 48 h is recommended. PMID:3639087

  6. Methicillin-resistant Staphylococcus aureus laryngitis.

    PubMed

    Liakos, Tracey; Kaye, Keith; Rubin, Adam D

    2010-09-01

    Infections due to methicillin-resistant Staphylococcus aureus (MRSA) have become more prevalent, in part because of the emergence and spread of community-acquired MRSA. This trend is particularly concerning because of the significant rates of morbidity and mortality associated with MRSA infections, and because MRSA strains are often resistant to many classes of antibiotics. Reports of infections of the head and neck, including wound infections, cellulitis, sinusitis, otitis media, and otitis externa, are well documented. However, to our knowledge, there have been no reports of bacterial laryngitis due to MRSA. We report the first published case of bacterial laryngitis caused by MRSA.

  7. Methicillin-Susceptible, Vancomycin-Resistant Staphylococcus aureus, Brazil.

    PubMed

    Panesso, Diana; Planet, Paul J; Diaz, Lorena; Hugonnet, Jean-Emmanuel; Tran, Truc T; Narechania, Apurva; Munita, Jose M; Rincon, Sandra; Carvajal, Lina P; Reyes, Jinnethe; Londoño, Alejandra; Smith, Hannah; Sebra, Robert; Deikus, Gintaras; Weinstock, George M; Murray, Barbara E; Rossi, Flavia; Arthur, Michel; Arias, Cesar A

    2015-10-01

    We report characterization of a methicillin-susceptible, vancomycin-resistant bloodstream isolate of Staphylococcus aureus recovered from a patient in Brazil. Emergence of vancomycin resistance in methicillin-susceptible S. aureus would indicate that this resistance trait might be poised to disseminate more rapidly among S. aureus and represents a major public health threat. PMID:26402569

  8. Methicillin-Susceptible, Vancomycin-Resistant Staphylococcus aureus, Brazil.

    PubMed

    Panesso, Diana; Planet, Paul J; Diaz, Lorena; Hugonnet, Jean-Emmanuel; Tran, Truc T; Narechania, Apurva; Munita, Jose M; Rincon, Sandra; Carvajal, Lina P; Reyes, Jinnethe; Londoño, Alejandra; Smith, Hannah; Sebra, Robert; Deikus, Gintaras; Weinstock, George M; Murray, Barbara E; Rossi, Flavia; Arthur, Michel; Arias, Cesar A

    2015-10-01

    We report characterization of a methicillin-susceptible, vancomycin-resistant bloodstream isolate of Staphylococcus aureus recovered from a patient in Brazil. Emergence of vancomycin resistance in methicillin-susceptible S. aureus would indicate that this resistance trait might be poised to disseminate more rapidly among S. aureus and represents a major public health threat.

  9. Methicillin-resistant Staphylococcus aureus, Western Australia

    PubMed Central

    Dailey, Lynne; Coombs, Geoffrey W.; O'Brien, Frances G.; Pearman, John W.; Christiansen, Keryn; Grubb, Warren B.

    2005-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a notable cause of hospital-acquired infections. A statewide screening and control policy was implemented in Western Australia (WA) after an outbreak of epidemic MRSA in a Perth hospital in 1982. We report on statutory notifications from1998 to 2002 and review the 20-year period from 1983 to 2002. The rate of reporting of community-associated Western Australia MRSA (WAMRSA) escalated from 1998 to 2002 but may have peaked in 2001. Several outbreaks were halted, but they resulted in an increase in reports as a result of screening. A notable increase in ciprofloxacin resistance during the study period was observed as a result of more United Kingdom epidemic MRSA (EMRSA) -15 and -16. WA has seen a persistently low incidence of multidrug-resistant MRSA because of the screening and decolonization program. Non–multidrug-resistant, community-associated WAMRSA strains have not established in WA hospitals. PMID:16318700

  10. [Drug resistance in nosocomial strains of staphylococci to methicillin].

    PubMed

    Sawicka-Grzelak, A; Rokosz, A; Meisel-Mikołajczyk, F

    1998-01-01

    The aim of the present study was the analysis of drug susceptibility of MRSA and MRCNS strains isolated from patients hospitalized in 14 wards of the State Clinical Hospital No 1 in Warsaw. The strains were identified (ID 32 STAPH), and their susceptibility to antimicrobial agents (ATB STAPH) was determined in ATB system (bioMérieux, France). Four methods were applied to confirm the resistance to methicillin: ATB-plus system, disc-diffusion method (Oxa 1 microgram, Oxoid, U.K.), Crystal MRSA ID (Becton Dickinson-BBL, USA) and agar screen test in TSA medium (Difco, USA) with methicillin (25 mg/l, Sigma, USA). 108 Staphylococcus spp. strains were found in 300 clinical specimens. 56 strains were methicillin-resistant (52%). Among methicillin-resistant strains 13 MRSA, 28 MRSE and 15 of other species were found. All MRSA strains were susceptible to vancomycin, teicoplanin and fusidic acid. MRCNS were susceptible first of all to vancomycin (43/43), minocycline (42/43) and pristinamycin (42/43). On the basis of the obtained results it can be stated that methicillin-resistant staphylococci occur in hospital wards. The greatest number of methicillin-resistant strains was cultured from patients hospitalized in surgery wards (32), methicillin-resistant strains much more frequently occur among coagulase-negative staphylococci, especially in Staphylococcus epidermis. Glycopeptide antibiotics are most active against isolated MRSA strains. The most active therapeutic agent against MRCNS is vancomycin. PMID:9857608

  11. Methicillin-resistant Staphylococcus aureus antibiotic resistance and virulence.

    PubMed

    Xia, Jufeng; Gao, Jianjun; Kokudo, Norihiro; Hasegawa, Kiyoshi; Tang, Wei

    2013-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most critical causes of healthcare-related or community-related infections. Resistance to most β-lactam antibiotics makes MRSA a big threat to clinical treatment. Utilization of low efficiency antibiotics such as vancomycin and teicoplanin makes new choices for therapies. Recently, much researchhas shed light on relevance between genetic mutations of MRSA and clinical characteristics such as antibiotic resistance, and virulence. These findings could contribute to development of novel antibiotics and vaccines.

  12. Expression of methicillin resistance in heterogeneous strains of Staphylococcus aureus.

    PubMed Central

    Hartman, B J; Tomasz, A

    1986-01-01

    The phenotypic expression of methicillin resistance was studied in a number of clinical isolates and laboratory strains of Staphylococcus aureus. The methicillin-resistant S. aureus strains could be divided into three classes, homogeneous, heterogeneous, and thermosensitive heterogeneous methicillin-resistant S. aureus, on the basis of their plating efficiencies at 30 or 37 degrees C on methicillin-containing agar plates. Heterogeneous strains of methicillin-resistant S. aureus were composed of two subpopulations: a small minority of cells (10(-5) to 10(-3); MIC, 600 to 1,000 micrograms/ml) that expressed resistance to high concentrations of methicillin at 37 degrees C, and a majority of cells (MIC, 5 micrograms/ml) that remained susceptible to the drug at 37 degrees C. Cultures of a thermosensitive heterogeneous strain were able to grow in the presence of high concentrations of methicillin, provided that the growth temperature was 30 degrees C. Such cultures lost their phenotypic resistance within 30 min (i.e., in less than one doubling time) after the growth temperature was shifted to the nonpermissive 37 degrees C. Shift of the temperature of the culture in the reverse direction (37 to 30 degrees C) resulted in an equally rapid expression of phenotypic resistance. The majority of the cells in such heterogeneous strains may be considered heat (or salt) conditional in their phenotypic expression of methicillin resistance. Both heterogeneous and thermosensitive heterogeneous strains, irrespective of their temperature of cultivation and degree of phenotypic resistance, contained detectable quantities of the 78-kilodalton penicillin-binding protein 2a (PBP 2a) that previous studies have suggested is a biochemical correlate of methicillin resistance in homogeneous strains of methicillin-resistant S. aureus. However, in contrast to the homogeneous stains, in heterogeneous and thermosensitive heterogeneous isolates the ability to synthesize PBP 2a is apparently not

  13. Restriction maps of the regions coding for methicillin and tobramycin resistances on chromosomal DNA in methicillin-resistant staphylococci.

    PubMed Central

    Ubukata, K; Nonoguchi, R; Matsuhashi, M; Song, M D; Konno, M

    1989-01-01

    Chromosomal BamHI DNA fragments containing both the mecA gene encoding the penicillin-binding protein responsible for methicillin resistance and the aadD gene encoding 4',4"-adenylyltransferase responsible for tobramycin resistance were cloned from three methicillin- and tobramycin-resistant strains of Staphylococcus aureus and one strain of Staphylococcus epidermidis. Physical maps of the fragments were similar, suggesting their unique origin. Images PMID:2817861

  14. Changing Trends in Resistance Pattern of Methicillin Resistant Staphylococcus aureus

    PubMed Central

    Kali, Arunava; Stephen, Selvaraj; Umadevi, Sivaraman; Kumar, Shailesh; Joseph, Noyal Mariya; Srirangaraj, Sreenivasan

    2013-01-01

    Background: Methicillin resistance in Staphylococcus aureus is associated with multidrug resistance, an aggressive course, increased mortality and morbidity in both community and health care facilities. Monitoring of newly emerging and prevalent Methicillin Resistant Staphylococcus aureus (MRSA) strains for their resistance patterns to conventional as well as novel drugs, are essential for infection control. Aims: To study the changing trends in resistance patterns of MRSA at our hospital. Settings and Design: This cross sectional study was carried out in a 750 bed tertiary care hospital in south India. Material and Methods: One hundred and two clinical isolates of MRSA which were obtained in 2004-2011 were identified by using oxacillin, cefoxitin disc diffusion test and oxacillin screening agar test. Antibiotic susceptibility test was done for commonly used non beta lactam anti-Staphylococcal drugs, as well as for anti-MRSA drugs like vancomycin, linezolid, mupirocin and rifampicin. Minimum inhibitory concentration (MIC) of vancomycin was determined by using Vancomycin HiComb strip (Himedia, Mumbai, India). Statistical Analysis which was done: Chi-square test and proportions were used to compare the two groups. Results: MRSA isolates showed high resistance to co-trimoxazole (82.3%), ciprofloxacin (76.4%), gentamicin (64.7%) and tetracycline (49%) as compared to other drugs. High prevalence of ciprofloxacin resistance was detected, particularly among outpatients. Multi resistant MRSA with a ≥ 3 non-beta lactam agent resistance was 79%. All MRSA isolates were sensitive to vancomycin, linezolid, mupirocin and rifampicin. MRSA had displayed increase in resistance to most antibiotics except tetracycline in recent years. Conclusions: Taking into consideration the prevalence of multidrug resistance in MRSA, resistance patterns should be evaluated periodically and antibiotic therapy should be guided by susceptibility testing. PMID:24179914

  15. Modulation of ccrAB Expression and SCCmec Excision by an Inverted Repeat Element and SarS in Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Zhang, Shijie; Ma, Ronghua; Liu, Xiaoyu; Zhang, Xu

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious human pathogen that can cause a broad spectrum of infections. MRSA strains are resistant to almost the entire family of β-lactam antibiotics due to the acquisition of staphylococcal cassette chromosome mec (SCCmec). The chromosome cassette recombinases A and B, encoded by ccrAB genes located on SCCmec, play a key role in the excision of SCCmec. Studies have shown that ccrAB genes are expressed in only a minority of cells, suggesting the involvement of a subtle regulatory mechanism in ccrAB expression which has not been uncovered. Here, we found that an inverted repeat (IR) element, existing extensively and conservatively within the ccrAB promoter of different SCCmec types, played a repressive role in ccrAB expression and SCCmec excision in MRSA strain N315. Replacement of the IR sequence led to a significant increase in ccrAB expression and curing of SCCmec from strain N315 cells. In addition, we identified the transcriptional regulator SarS using DNA-affinity chromatography and further demonstrated that SarS can bind to the IR sequence and upregulate ccrAB expression and SCCmec excision. These findings reveal a molecular mechanism regulating ccrAB expression and SCCmec excision and may provide mechanic insights into the lateral transfer of SCCmec and spread of antibiotic resistance in S. aureus. PMID:26248371

  16. Molecular mechanisms of methicillin resistance in Staphylococcus aureus.

    PubMed

    Domínguez, M A; Liñares, J; Martín, R

    1997-09-01

    Methicillin-resistant Staphylococcus aureus (MRSA) strains are among the most common nosocomial pathogens. The most significant mechanism of resistance to methicillin in this-species is the acquisition of a genetic determinant (mecA gene). However, resistance seems to have a more complex molecular basis, since additional chromosomal material is involved in such resistance. Besides, overproduction of penicillinase and/or alterations in the PBPs can contribute to the formation of resistance phenotypes. Genetic and environmental factors leading to MRSA are reviewed.

  17. Imported Methicillin-Resistant Staphylococcus aureus, Sweden

    PubMed Central

    Örtqvist, Åke; Ringberg, Håkan; Larsson, Leif; Olsson-Liljequist, Barbro; Hæggman, Sara; Kalin, Mats; Ekdahl, Karl

    2010-01-01

    Countries such as Sweden that have a low prevalence of methicillin-resistant Staphylococcus aureus (MRSA) offer the opportunity to discern and study transmission of imported cases of MRSA. We analyzed 444 imported cases of MRSA acquisition reported in Sweden during 2000–2003. Risk for MRSA in returning travelers ranged from 0.1 (95% confidence interval [CI] 0.01–0.4) per 1 million travelers to Nordic countries to 59.4 (95% CI 44.5–79.3) per 1 million travelers to North Africa and the Middle East. Most imported cases (246, 55%) were healthcare acquired, but regions with the highest risk for MRSA in travelers showed a correlation with community acquisition (r = 0.81, p = 0.001). Characteristic differences in MRSA strains acquired were dependent on the region from which they originated and whether they were community or healthcare acquired. Knowledge of differences in transmission of MRSA may improve control measures against imported cases. PMID:20113546

  18. Antibacterial Activity of Extracts of Acacia Aroma Against Methicillin-Resistant And Methicillin-Sensitive Staphylococcus

    PubMed Central

    Mattana, C.M.; Satorres, S.E.; Sosa, A.; Fusco, M.; Alcará, L.E.

    2010-01-01

    Antibacterial activity of organic and aqueous extracts of Acacia aroma was evaluated against methicillin-resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus epidermidis. Inhibition of bacterial growth was determined using agar diffusion and bioautographic methods. Among all assayed organic extracts only ethanolic and ethyl acetate extracts presented highest activities against all tested Staphylococcus strains with minimal inhibitory concentration (MIC) values ranging from 2.5 to 10 mg/ml and from 2.5 to 5 mg/ml respectively. The aqueous extracts show little antibacterial activity against Staphylococcus strains. The bioautography assay demonstrated well-defined growth inhibition zones against S. aureus in correspondence with flavonoids and saponins. A. aroma would be an interesting topic for further study and possibly for an alternative treatment for skin infections. PMID:24031532

  19. Is methicillin-resistant Staphylococcus aureus replacing methicillin-susceptible S. aureus?

    PubMed Central

    Mostofsky, Elizabeth; Lipsitch, Marc; Regev-Yochay, Gili

    2011-01-01

    Despite extensive research on the emergence of and treatments for methicillin-resistant Staphylococcus aureus (MRSA), prior studies have not rigorously evaluated the impact of methicillin resistance on the overall incidence of S. aureus infections. Yet, there are direct clinical and research implications of determining whether methicillin-susceptible S. aureus (MSSA) infection rates remain stable in the face of increasing MRSA prevalence or whether MSSA will be replaced over time. A synthesis of prior studies indicates that the emergence of healthcare-associated MRSA (HA-MRSA) and community-associated MRSA (CA-MRSA) has led to an increase in the overall incidence of S. aureus infections, with MRSA principally adding to, rather than replacing, MSSA. However, colonization with CA-MRSA may at least partially replace colonization with MSSA. So far, evidence indicates that MSSA still accounts for many infections. Therefore, eradication of MRSA alone is not sufficient to address the public health burden of S. aureus. PMID:21737459

  20. Staphylococcal methicillin resistance: fine focus on folds and functions.

    PubMed

    Mallorquí-Fernández, Goretti; Marrero, Aniebrys; García-Piquè, Sonia; García-Castellanos, Raquel; Gomis-Rüth, F Xavier

    2004-06-01

    Globalisation has entailed a massive increase in trade and human mobility facilitating the rapid spread of infectious agents, including those that are drug resistant. A particularly serious threat to human health is posed by methicillin-resistant staphylococcal strains which have acquired molecular mechanisms to evade the action of beta-lactam antibiotics (BLAs). Full expression of high-level methicillin resistance involves a complex network of molecules and depends primarily on sufficient expression of a penicillin-binding protein with low sensitivity towards BLAs. Other factors include the fine-tuned regulation of autolytic activity of cell-wall components, as well as an optimal rate of peptidoglycan precursor formation and a highly specific peptidoglycan precursor structure. Three-dimensional structural data are available on several of the pieces involved in the jigsaw puzzle and provide a molecular basis for the understanding of methicillin resistance and for the design of new therapeutic strategies.

  1. [The development and testing of reagents kit for detection and qualitative evaluation of DNA of methicillin sensitive and methicillin resistant Staphylococcus aureus and also methicillin resistant coagulase negative Staphylococcus spp. applying technique of polymerase chain reaction in "real time" mode].

    PubMed

    Skachkova, T S; Shipulina, O Iu; Domonova, É A; Subbotovskaia, A I; Kozyreva, V S; Il'ina, V N; Shipulin, G A

    2013-06-01

    The reagents kit is developed to identify and quantitatively detect DNA of methicillin sensitive and methicillin resistant Staphylococcus aureus, methicillin resistant coagulase negative Staphylococcus spp. in biological material using technique of polymerase chain reaction with hybridizational fluorescent detection and having higher analytical and diagnostic characteristics. The application of the given reagents kit makes it possible to optimize the epidemiologic monitoring of propagation of methicillin resistant strains of Staphylococcus spp. Significantly decreasing duration and laboriousness of study.

  2. Community-acquired Methicillin-resistant Staphylococcus aureus, Uruguay

    PubMed Central

    Ma, Xiao Xue; Galiana, Antonio; Pedreira, Walter; Mowszowicz, Martin; Christophersen, Inés; Machiavello, Silvia; Lope, Liliana; Benaderet, Sara; Buela, Fernanda; Vicentino, Walter; Albini, María; Bertaux, Olivier; Constenla, Irene; Bagnulo, Homero; Llosa, Luis; Ito, Teruyo

    2005-01-01

    A novel, methicillin-resistant Staphylococcus aureus clone (Uruguay clone) with a non–multidrug-resistant phenotype caused a large outbreak, including 7 deaths, in Montevideo, Uruguay. The clone was distinct from the highly virulent community clone represented by strain MW2, although both clones carried Panton-Valentine leukocidin gene and cna gene. PMID:15963301

  3. Reversion From Methicillin Susceptibility to Methicillin Resistance in Staphylococcus aureus During Treatment of Bacteremia.

    PubMed

    Proulx, Megan K; Palace, Samantha G; Gandra, Sumanth; Torres, Brenda; Weir, Susan; Stiles, Tracy; Ellison, Richard T; Goguen, Jon D

    2016-03-15

    Approximately 3% of Staphylococcus aureus strains that, according to results of conventional phenotypic methods, are highly susceptible to methicillin-like antibiotics also have polymerase chain reaction (PCR) results positive for mecA. The genetic nature of these mecA-positive methicillin-susceptible S. aureus (MSSA) strains has not been investigated. We report the first clearly defined case of reversion from methicillin susceptibility to methicillin resistance among mecA-positive MSSA within a patient during antibiotic therapy. We describe the mechanism of reversion for this strain and for a second clinical isolate that reverts at a similar frequency. The rates of reversion are of the same order of magnitude as spontaneous resistance to drugs like rifampicin. When mecA is detected by PCR in the clinical laboratory, current guidelines recommend that these strains be reported as resistant. Because combination therapy using both a β-lactam and a second antibiotic suppressing the small revertant population may be superior to alternatives such as vancomycin, the benefits of distinguishing between mecA-positive MSSA and MRSA in clinical reports should be evaluated.

  4. Isolation of methicillin-resistant staphylococci in the dental operatory.

    PubMed

    Horiba, N; Yoshida, T; Suzuki, K; Maekawa, Y; Ito, M; Matsumoto, T; Nakamura, H

    1995-01-01

    The state of contamination by methicillin-resistant Staphylococci, including methicillin-resistant Staphylococcus aureus (MRSA) at the conservative dentistry section of the School of Dentistry, Aichi-Gakuin University, was investigated. Methicillin-resistant coagulase-negative Staphylococci (MRCNS) were detected in 8 (20.5%) of 39 dental staff (28 dentists, 8 dental hygienists, and 3 dental assistants), but MRSA was not detected. MRCNS was also detected in locations such as the dental chair, dental bracket, dental cabinet, and floor, as well as in airborne samples. The presence of the same strain in both the oral cavity of staff persons and the dental chair/floor locations was determined by biochemical properties, antibiotic sensitivity tests, and electrophoretic patterns.

  5. Response of Methicillin-Resistant Staphylococcus aureus to Amicoumacin A

    PubMed Central

    Chon, Tai; Wiersma, Anna M.; Sit, Clarissa S.; Vederas, John C.; Hecker, Michael; Nakano, Michiko M.

    2012-01-01

    Amicoumacin A exhibits strong antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA), hence we sought to uncover its mechanism of action. Genome-wide transcriptome analysis of S. aureus COL in response to amicoumacin A showed alteration in transcription of genes specifying several cellular processes including cell envelope turnover, cross-membrane transport, virulence, metabolism, and general stress response. The most highly induced gene was lrgA, encoding an antiholin-like product, which is induced in cells undergoing a collapse of Δψ. Consistent with the notion that LrgA modulates murein hydrolase activity, COL grown in the presence of amicoumacin A showed reduced autolysis, which was primarily caused by lower hydrolase activity. To gain further insight into the mechanism of action of amicoumacin A, a whole genome comparison of wild-type COL and amicoumacin A-resistant mutants isolated by a serial passage method was carried out. Single point mutations generating codon substitutions were uncovered in ksgA (encoding RNA dimethyltransferase), fusA (elongation factor G), dnaG (primase), lacD (tagatose 1,6-bisphosphate aldolase), and SACOL0611 (a putative glycosyl transferase). The codon substitutions in EF-G that cause amicoumacin A resistance and fusidic acid resistance reside in separate domains and do not bring about cross resistance. Taken together, these results suggest that amicoumacin A might cause perturbation of the cell membrane and lead to energy dissipation. Decreased rates of cellular metabolism including protein synthesis and DNA replication in resistant strains might allow cells to compensate for membrane dysfunction and thus increase cell survivability. PMID:22479511

  6. Methicillin resistant coagulase negative staphylococcus: From colonizer to a pathogen.

    PubMed

    Gilani, Mehreen; Usman, Javaid; Latif, Mahwish; Munir, Tehmina; Gill, Maria Mushtaq; Anjum, Rabia; Babar, Nazish

    2016-07-01

    The objective of our study was to determine the frequency of methicillin resistance in coagulase negative Staphylococcus (CoNS) and to determine its in-vitro antimicrobial susceptibility to various other routinely used antibiotics. It was a cross sectional study conducted at the department of Microbiology, Army Medical College, Rawalpindi, Pakistan from June 2011 to May 2012. The organisms were identified on the basis of colony morphology, Gram staining, catalase, DNAase and slide/tube coagulase tests. The organisms were considered to be methicillin resistant when the diameter of zone of inhibition was less than 25mm around 30μg cefoxitin disc. Antibiotic sensitivity was determined using the Modified Kirby-Bauer disc diffusion method. From a total of 337 CoNS, 201 were methicillin resistant and were included in the study. All were resistant to Penicillin, followed by Erythromycin (93•1%), Ciprofloxacin (77%), Co-trimoxazole (74•8%), Gentamicin (68•3%), Clindamycin (51•06%), Tetracycline (44•6%), Fusidic acid (40%), Rifampicin (39•5%), Chloramphenicol (19•3%), Linezolid (2%), Minocycline (1•1%), and Vancomycin (0%). More than half of CoNS were methicillin resistant. Vancomycin is the only drug to which all of the MRCoNS were sensitive, with more than 98% of the isolates being sensitive to Linezolid and Minocycline. PMID:27393446

  7. Methicillin resistant coagulase negative staphylococcus: From colonizer to a pathogen.

    PubMed

    Gilani, Mehreen; Usman, Javaid; Latif, Mahwish; Munir, Tehmina; Gill, Maria Mushtaq; Anjum, Rabia; Babar, Nazish

    2016-07-01

    The objective of our study was to determine the frequency of methicillin resistance in coagulase negative Staphylococcus (CoNS) and to determine its in-vitro antimicrobial susceptibility to various other routinely used antibiotics. It was a cross sectional study conducted at the department of Microbiology, Army Medical College, Rawalpindi, Pakistan from June 2011 to May 2012. The organisms were identified on the basis of colony morphology, Gram staining, catalase, DNAase and slide/tube coagulase tests. The organisms were considered to be methicillin resistant when the diameter of zone of inhibition was less than 25mm around 30μg cefoxitin disc. Antibiotic sensitivity was determined using the Modified Kirby-Bauer disc diffusion method. From a total of 337 CoNS, 201 were methicillin resistant and were included in the study. All were resistant to Penicillin, followed by Erythromycin (93•1%), Ciprofloxacin (77%), Co-trimoxazole (74•8%), Gentamicin (68•3%), Clindamycin (51•06%), Tetracycline (44•6%), Fusidic acid (40%), Rifampicin (39•5%), Chloramphenicol (19•3%), Linezolid (2%), Minocycline (1•1%), and Vancomycin (0%). More than half of CoNS were methicillin resistant. Vancomycin is the only drug to which all of the MRCoNS were sensitive, with more than 98% of the isolates being sensitive to Linezolid and Minocycline.

  8. Methicillin resistance and the biofilm phenotype in Staphylococcus aureus

    PubMed Central

    McCarthy, Hannah; Rudkin, Justine K.; Black, Nikki S.; Gallagher, Laura; O'Neill, Eoghan; O'Gara, James P.

    2015-01-01

    Antibiotic resistance and biofilm-forming capacity contribute to the success of Staphylococcus aureus as a human pathogen in both healthcare and community settings. These virulence factors do not function independently of each other and the biofilm phenotype expressed by clinical isolates of S. aureus is influenced by acquisition of the methicillin resistance gene mecA. Methicillin-sensitive S. aureus (MSSA) strains commonly produce an icaADBC operon-encoded polysaccharide intercellular adhesin (PIA)-dependent biofilm. In contrast, the release of extracellular DNA (eDNA) and cell surface expression of a number of sortase-anchored proteins, and the major autolysin have been implicated in the biofilm phenotype of methicillin-resistant S. aureus (MRSA) isolates. Expression of high level methicillin resistance in a laboratory MSSA strain resulted in (i) repression of PIA-mediated biofilm production, (ii) down-regulation of the accessory gene regulator (Agr) system, and (iii) attenuation of virulence in murine sepsis and device infection models. Here we review the mechanisms of MSSA and MRSA biofilm production and the relationships between antibiotic resistance, biofilm and virulence gene regulation in S. aureus. PMID:25674541

  9. Incidence of methicillin resistant coagulase positive & coagulase negative staphylococci in blood cultures.

    PubMed

    Jesudason, M V; Anandaraj, W S; Jegadeesan, P

    1997-04-01

    Isolates of Staphylococcus aureus and coagulase negative staphylococci (CONS) from blood culture of bacteraemic patients were studied for methicillin resistance is 1993 and 1996. An increase in methicillin resistance among these isolates was observed in 1996. In 1993, 32.6 per cent isolates of S. aureus were methicillin resistant, this increased to 45.7 per cent in 1996. Methicillin resistance in CONS were 1.6 and 14.6 per cent respectively in 1993 and 1996. This increase in methicillin resistance may pose therapeutic problems and requires more effective drugs based on susceptibility testing of such isolates.

  10. Phenotypic Suppression of Methicillin Resistance in Staphylococcus aureus by Mutant Noninducible Penicillinase Plasmids1

    PubMed Central

    Cohen, Sidney; Gibson, Carol J.; Sweeney, H. M.

    1972-01-01

    Methicillin (intrinsic) resistance of Staphylococcus aureus was suppressed almost completely by regulatory gene (penI1) mutations of penicillinase plasmids that made penicillinase production strictly noninducible. Methicillin resistance was restored by secondary regulatory gene mutations that altered the noninducible phenotype or by complementation with a compatible plasmid that did not bear the noninducible mutation. No evidence was obtained for genetic linkage between a penicillinase plasmid and the gene for methicillin resistance. We suggest, therefore, that the mutant noninducible repressor acted in trans by binding to a site on the methicillin resistance determinant. This hypothesis would imply an appreciable degree of homology between penicillinase plasmids and methicillin resistance genes. PMID:5086657

  11. Endogenous methicillin-resistant Staphylococcus aureus endophthalmitis after leg trauma.

    PubMed

    Larson, Katie E; Carrillo-Marquez, Maria

    2015-08-01

    We present a case of endogenous endophthalmitis in a 13-year-old boy with methicillin-resistant Staphylococcus aureus sepsis. The patient underwent magnetic resonance imaging of the brain after intermittent anisocoria was noted on examination, leading to a diagnosis of endophthalmitis with a chorodial abscess.

  12. Public computer surfaces are reservoirs for methicillin-resistant staphylococci.

    PubMed

    Kassem, Issmat I; Sigler, Von; Esseili, Malak A

    2007-07-01

    The role of computer keyboards used by students of a metropolitan university as reservoirs of antibiotic-resistant staphylococci was determined. Putative methicillin (oxacillin)-resistant staphylococci isolates were identified from keyboard swabs following a combination of biochemical and genetic analyses. Of 24 keyboards surveyed, 17 were contaminated with staphylococci that grew in the presence of oxacillin (2 mg l(-1)). Methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA), -S. epidermidis (MRSE) and -S. hominis (MRSH) were present on two, five and two keyboards, respectively, while all three staphylococci co-contaminated one keyboard. Furthermore, these were found to be part of a greater community of oxacillin-resistant bacteria. Combined with the broad user base common to public computers, the presence of antibiotic-resistant staphylococci on keyboard surfaces might impact the transmission and prevalence of pathogens throughout the community.

  13. Typing of methicillin-resistant Staphylococcus aureus by antibiotic resistance phenotypes.

    PubMed

    Gillespie, M T; Lyon, B R; Skurray, R A

    1990-01-01

    The identification of new epidemic strains of methicillin-resistant Staphylococcus aureus is essential for rapid, effective infection control. We have developed a typing method which uses antibiotic sensitivity patterns to differentiate methicillin-resistant S. aureus and which is faster and more cost-effective than biochemical analysis or bacteriophage typing. Characterisation of phenotypes which are chromosomally-encoded, plasmid- or chromosomally-encoded or exclusively plasmid-mediated has enabled us to separate Australian strains of methicillin-resistant S. aureus into 11 classes, representatives of which were indistinguishable by bacteriophage type, or plasmid profile alone. The value of this procedure is thus clearly shown.

  14. Prevalence of Methicillin-Resistant and Methicillin-Susceptible S. Aureusin the Saliva of Health Professionals

    PubMed Central

    de Carvalho, Milton Jorge; Pimenta, Fabiana Cristina; Hayashida, Miyeko; Gir, Elucir; da Silva, Adriana Maria; Barbosa, Caio Parente; da Silva Canini, Silvia Rita Marin; Santiago, Silvana

    2009-01-01

    INTRODUCTION: S. aureus is one of the main agents of nosocomial infection and is sometimes difficult to treat with currently available active antimicrobials. PURPOSE: To analyze the prevalence of methicillin-susceptible S.aureus (MSSA) and methicillin-resistant S. aureus (MRSA) as well as the MRSA antimicrobial susceptibility profile isolated in the saliva of health professionals at a large public education hospital. MATERIALS AND METHODS: The project was approved by the research and ethics committee of the institution under study. Three samples of saliva from 340 health professionals were collected. The saliva analysis used to identify S. aureus was based on mannitol fermentation tests, catalase production, coagulase, DNAse, and lecithinase. In order to detect MRSA, samples were submitted to the disk diffusion test and the oxacillin agar screening test. In order to identify the minimum inhibitory concentration, the Etest® technique was used. RESULTS: The prevalence of MSSA was 43.5% (148/340), and MRSA was 4.1% (14/340). MRSA detected by the diffusion disk test, was 100% resistant to penicillin and oxacillin, 92.9% resistant to erythromycin, 57.1% resistant to clindamycin, 42.9% resistant to ciprofloxacin and 57.1% resistant to cefoxetin. CONCLUSION: This subject is important for both the education of health professionals and for preventative measures. Standard and contact-precautions should be employed in professional practice. PMID:19488585

  15. Methicillin-resistant staphylococci: implications for our food supply?

    PubMed

    Doyle, M Ellin; Hartmann, Faye A; Lee Wong, Amy C

    2012-12-01

    Food-borne intoxication, caused by heat-stable enterotoxins produced by Staphylococcus aureus, causes over 240,000 cases of food-borne illness in the United States annually. Other staphylococci commonly associated with animals may also produce these enterotoxins. Foods may be contaminated by infected food handlers during slaughter and processing of livestock or by cross-contamination during food preparation. S. aureus also causes a variety of mild to severe skin and soft tissue infections in humans and other animals. Antibiotic resistance is common in staphylococci. Hospital-associated (HA) S. aureus are resistant to numerous antibiotics, with methicillin-resistant S. aureus (MRSA) presenting significant challenges in health care facilities for over 40 years. During the mid-1990s new human MRSA strains developed outside of hospitals and were termed community-associated (CA). A few years later, MRSA was isolated from horses and methicillin resistance was detected in Staphylococcus intermedius/pseudintermedius from dogs and cats. In 2003, a livestock-associated (LA) MRSA strain was first detected in swine. These methicillin-resistant staphylococci pose additional food safety and occupational health concerns. MRSA has been detected in a small percentage of retail meat and raw milk samples indicating a potential risk for food-borne transmission of MRSA. Persons working with animals or handling meat products may be at increased risk for antibiotic-resistant infections. This review discusses the scope of the problem of methicillin-resistant staphylococci and some strategies for control of these bacteria and prevention of illness.

  16. Impetigo update: new challenges in the era of methicillin resistance.

    PubMed

    Geria, Aanand N; Schwartz, Robert A

    2010-02-01

    Impetigo is a bacterial infection of the superficial epidermis most commonly seen in infants and children. It is clinically characterized by crusted erosions or ulcers that may arise as a primary infection in which bacterial invasion occurs through minor breaks in the cutaneous surface or a secondary infection of a preexisting dermatosis or infestation. Impetigo occurs in 2 forms: bullous and nonbullous. Staphylococcus aureus currently is the most common overall cause of impetigo, but Streptococcus pyogenes remains an important cause in developing nations. Community-acquired methicillin-resistant S aureus (CA-MRSA) poses a challenge because of its enhanced virulence and increasing prevalence in children. For limited uncomplicated impetigo, either topical mupirocin or fusidic acid is as effective if not more effective than systemic antibiotics. For extensive or complicated impetigo, systemic antibiotics may be warranted, but beta-lactam antibiotics should be avoided if methicillin-resistant S aureus (MRSA) is suspected.

  17. A model for surveillance of methicillin-resistant Staphylococcus aureus.

    PubMed

    Simons, Hannah; Alcabes, Philip

    2008-01-01

    It is well recognized that methicillin-resistant Staphylococcus aureus (MRSA) has become a community pathogen. Several key differences between community-associated and hospital-associated MRSA strains exist, including distinct methicillin resistance genes and genetic backgrounds and differing susceptibility to antibiotics. Recent studies have demonstrated that typical hospital and community strains easily move between hospital and community environments. Despite evidence of MRSA's expanding reach in the community, the best methods for population-level detection and containment have not been established. In an effort to determine effective methods for monitoring the spread of MRSA, we reviewed the literature on hospital-associated and community-associated MRSA (CA-MRSA) in the community and proposed a model for enhanced surveillance. By linking epidemiologic and molecular techniques within a surveillance system that coordinates activities in the community and health-care setting, scientists and public health officials can begin to measure the true extent of CA-MRSA in communities and hospitals.

  18. Comparative activity of CGP 31608, nafcillin, cefamandole, imipenem, and vancomycin against methicillin-susceptible and methicillin-resistant staphylococci.

    PubMed

    Sachdeva, M; Hackbarth, C; Stella, F B; Chambers, H F

    1987-10-01

    The activity of CGP 31608 for 53 strains of Staphylococcus aureus and 48 strains of S. epidermidis, both methicillin susceptible and resistant, was compared with that of vancomycin, nafcillin, cefamandole, and imipenem. Microdilution MICs were determined in Mueller-Hinton broth with or without 2.5% NaCl at an inoculum of 3 x 10(5) CFU/ml with a 20-h, 37 degrees C incubation. The MICs of imipenem and CGP 31608 for methicillin-resistant strains were lower than the MICs of nafcillin or cefamandole for these strains; these differences diminished in the presence of 2.5% NaCl. Subpopulations were detected in strains of methicillin-resistant S. aureus and S. epidermidis that were resistant to all the beta-lactam antibiotics tested at 5 micrograms/ml. This resistant subpopulation produced progeny that were uniformly resistant to high concentrations of each of the beta-lactams.

  19. Comparative activity of CGP 31608, nafcillin, cefamandole, imipenem, and vancomycin against methicillin-susceptible and methicillin-resistant staphylococci.

    PubMed

    Sachdeva, M; Hackbarth, C; Stella, F B; Chambers, H F

    1987-10-01

    The activity of CGP 31608 for 53 strains of Staphylococcus aureus and 48 strains of S. epidermidis, both methicillin susceptible and resistant, was compared with that of vancomycin, nafcillin, cefamandole, and imipenem. Microdilution MICs were determined in Mueller-Hinton broth with or without 2.5% NaCl at an inoculum of 3 x 10(5) CFU/ml with a 20-h, 37 degrees C incubation. The MICs of imipenem and CGP 31608 for methicillin-resistant strains were lower than the MICs of nafcillin or cefamandole for these strains; these differences diminished in the presence of 2.5% NaCl. Subpopulations were detected in strains of methicillin-resistant S. aureus and S. epidermidis that were resistant to all the beta-lactam antibiotics tested at 5 micrograms/ml. This resistant subpopulation produced progeny that were uniformly resistant to high concentrations of each of the beta-lactams. PMID:3481245

  20. Comparison of Biofilm Formation between Methicillin-Resistant and Methicillin-Susceptible Isolates of Staphylococcus aureus

    PubMed Central

    Ghasemian, Abdolmajid; Najar Peerayeh, Shahin; Bakhshi, Bita; Mirzaee, Mohsen

    2016-01-01

    Background: The aim of this study was to compare the biofilm formation and the prevalence of biofilm-associated genes between the isolates of methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus. Methods: In total, 209 S. aureus isolates were collected. The antibiotic susceptibility test was conducted using nine antibiotics according to the guidelines of Clinical and Laboratory Standards Institute. Phenotypic biofilm formation was performed with microtiter plate assay. The polymerase chain reaction was employed to detect icaA, icaD, icaB, icaC, clfA, clfB, fnbA, fnbB, fib, cna, eno, ebps, bbp, mecA, and SCCmec types as well as agr group genes with specific primers. Results: Sixty-four (30.62%) isolates were resistant to methicillin, and 54 (83%) MRSA harbored SCCmec III. Furthermore, 122 (58.3%) isolates belonged to agr group I. Twenty-six (36.1%) MRSA and 42 (28.9%) MSSA isolates were strong biofilm producers (no significant difference). The prevalence of icaA, icaD, icaB, and icaC genes in MSSA isolates was 71, 41, 76, and 72%, respectively. The frequency of clfA, clfB, fnbA, fnbB, fib, cna, eno, ebps, and bbp in MSSA was 100, 100, 56, 46, 74, 54, 78, 11, and 1%, respectively. However, in MRSA isolates, the frequency was 97, 97, 64, 51, 76, 56, 79, and 12% with no track of bbp, respectively. Conclusion: Statistical difference between MSSA and MRSA regarding biofilm formation and the frequency of all biofilm-encoding genes was not significant. The majority of the S. aureus isolates harbored clfA, clfB, eno, fib, icaA, and icaD genes. PMID:26948126

  1. Nosocomial Infections and Drug Susceptibility Patterns in Methicillin Sensitive and Methicillin Resistant Staphylococcus aureus

    PubMed Central

    Sharma, Nitish Kumar; Garg, Raina; Baliga, Shrikala; Bhat K., Gopalkrishna

    2013-01-01

    Aim: Staphylococcus aureus is one of the leading causes of nosocomial infections and is known for its ability to develop resistance to antibiotics. The drug susceptibility pattern of Methicillin Sensitive S. aureus (MSSA) and Methicillin Resistant S. aureus (MRSA) may vary. Aims and Objectives: This study was carried out to determine and compare the drug susceptibility patterns in nosocomial MSSA and MRSA. Material and Methods: The study was conducted between September 2009 and August 2011. Standard conventional methods were used for the isolation and identification of S. aureus. MRSA was identified by the cefoxitin (30 μg) disk method. Antibiotic susceptibility test was done using Kirby-Bauer disk diffusion method and the interpretation of the results was done using CLSI guidelines. Results: Out of 685 strains of S. aureus studied, 173(25.25%) were MRSA and 512 (74.25%) were MSSA. Out of 173 MRSA strains, 114(65.89%) were isolated from pus, 22(12.71%) from vaginal swab, 18(10.40%) from central catheter tip and the remaining from other specimens. All isolates were susceptible to vancomycin and least number of isolates were susceptible to penicillin. MRSA displayed significantly higher resistance to other antibiotics. 45.7% of MRSA strains were resistant to clindamycin, 64.7% to ciprofloxacin, 87.3% to cotrimoxazole, 54.3% to erythromycin, 17.3% to gentamicin, 16.8% to netilmycin, and 58.38% to tetracycline. Inducible clindamycin resistance was detected in 37 (21.38%) strains of MRSA. Conclusion: Nosocomial infections caused by MRSA is a significant problem. MRSA and MSSA differ with their susceptibility to antibiotics. All MRSA isolates in our hospitals were susceptible to vancomycin. Proper selection of the antibiotics based on antibiotic susceptibility test results is needed for effective treatment and prevention of emergence of resistance in MRSA and MSSA. PMID:24298469

  2. Methicillin-Resistant Staphylococcus pseudintermedius in a Veterinary Teaching Hospital▿

    PubMed Central

    Sasaki, Takashi; Kikuchi, Ken; Tanaka, Yoshikazu; Takahashi, Namiko; Kamata, Shinichi; Hiramatsu, Keiichi

    2007-01-01

    We surveyed methicillin-resistant coagulase-positive staphylococcus (MRCPS) strains from 57 (26 inpatient and 31 outpatient) dogs and 20 veterinary staff in a veterinary teaching hospital. From the staff, three MRCPS strains were isolated, and two were methicillin-resistant Staphylococcus aureus (MRSA). In contrast, 18 MRCPS strains were detected in both inpatient (12 of 26 [46.2%]) and outpatient (6 of 31 [19.4%]) dogs. Among them, only one strain was MRSA. Using direct sequencing of sodA and hsp60 genes, the 18 MRCPS strains other than MRSA from a staff and 17 dogs, were finally identified as Staphylococcus pseudintermedius, a novel species of Staphylococcus from a cat. All of the methicillin-resistant S. pseudintermedius (MRSP) strains were multidrug resistant to erythromycin, clindamycin, trimethoprim-sulfamethoxazole, and levofloxacin. Most of the MRSP strains showed high-level resistance to oxacillin (≥128 μg/ml, 15 of 18 [83.3%]), and 10 of 15 (66.7%) high-level oxacillin-resistant MRSP strains carried type III SCCmec. DNA fingerprinting of MRSP strains by pulsed-field gel electrophoresis yielded eight clusters: clone A with four subtypes, clone B with four subtypes, clone C with three subtypes, and five other different single clones. MRSP strains from the staff and some inpatient and outpatient dogs shared three major clones (clones A, B, and C), but the strains of the other five different clusters were distributed independently among inpatient or outpatient dogs. This genetic diversity suggested that the MRSP strains were not only acquired in this veterinary teaching hospital but also acquired in primary veterinary clinics in the community. To our knowledge, this is the first report of MRSP in dogs and humans in a veterinary institution. PMID:17267624

  3. Haemodialysis nurses knowledge about methicillin-resistant Staphylococcus aureus.

    PubMed

    Lindberg, Maria; Lindberg, Magnus

    2012-06-01

    Healthcare workers may lack knowledge about antibiotic-resistant bacteria and thereby increase the spread of such organisms. The aim of the present study was to describe the relationship between self-rated knowledge and actual knowledge about methicillin-resistant Staphylococcus aureus (MRSA) among 326 Swedish haemodialysis nurses. Data were collected through a postal questionnaire. The findings suggest that ongoing education about MRSA should be provided to haemodialysis nurses, but also that standardised evaluation of adequate knowledge, skills and competencies' regarding safe practices is warranted. Future research should focus on effective mechanisms to ensure that haemodialysis nurses provide safe MRSA care. PMID:22085397

  4. Methicillin-Resistant Staphylococcus aureus (MRSA) Diagnosis

    MedlinePlus

    ... Resistance Funding Information National Library of Medicine, MedlinePlus ​​​​​​​​​​​​ Javascript Error Your browser JavaScript is turned off causing certain features of the ...

  5. Methicillin-Resistant Staphylococcus aureus (MRSA) Treatment

    MedlinePlus

    ... antibiotics, your provider will consider the potential for antibiotic resistance. Thus, if MRSA is suspected, your provider will avoid treating you with beta-lactam antibiotics, a class of antibiotic observed not to be ...

  6. Staphylococcus aureus CC398: Host Adaptation and Emergence of Methicillin Resistance in Livestock

    PubMed Central

    Price, Lance B.; Stegger, Marc; Hasman, Henrik; Aziz, Maliha; Larsen, Jesper; Andersen, Paal Skytt; Pearson, Talima; Waters, Andrew E.; Foster, Jeffrey T.; Schupp, James; Gillece, John; Driebe, Elizabeth; Liu, Cindy M.; Springer, Burkhard; Zdovc, Irena; Battisti, Antonio; Franco, Alessia; Żmudzki, Jacek; Schwarz, Stefan; Butaye, Patrick; Jouy, Eric; Pomba, Constanca; Porrero, M. Concepción; Ruimy, Raymond; Smith, Tara C.; Robinson, D. Ashley; Weese, J. Scott; Arriola, Carmen Sofia; Yu, Fangyou; Laurent, Frederic; Keim, Paul; Skov, Robert; Aarestrup, Frank M.

    2012-01-01

    ABSTRACT Since its discovery in the early 2000s, methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 398 (CC398) has become a rapidly emerging cause of human infections, most often associated with livestock exposure. We applied whole-genome sequence typing to characterize a diverse collection of CC398 isolates (n = 89), including MRSA and methicillin-susceptible S. aureus (MSSA) from animals and humans spanning 19 countries and four continents. We identified 4,238 single nucleotide polymorphisms (SNPs) among the 89 core genomes. Minimal homoplasy (consistency index = 0.9591) was detected among parsimony-informative SNPs, allowing for the generation of a highly accurate phylogenetic reconstruction of the CC398 clonal lineage. Phylogenetic analyses revealed that MSSA from humans formed the most ancestral clades. The most derived lineages were composed predominantly of livestock-associated MRSA possessing three different staphylococcal cassette chromosome mec element (SCCmec) types (IV, V, and VII-like) including nine subtypes. The human-associated isolates from the basal clades carried phages encoding human innate immune modulators that were largely missing among the livestock-associated isolates. Our results strongly suggest that livestock-associated MRSA CC398 originated in humans as MSSA. The lineage appears to have undergone a rapid radiation in conjunction with the jump from humans to livestock, where it subsequently acquired tetracycline and methicillin resistance. Further analyses are required to estimate the number of independent genetic events leading to the methicillin-resistant sublineages, but the diversity of SCCmec subtypes is suggestive of strong and diverse antimicrobial selection associated with food animal production. PMID:22354957

  7. Methicillin-resistant Staphylococcus aureus: an overview for manual therapists☆

    PubMed Central

    Green, Bart N.; Johnson, Claire D.; Egan, Jonathon Todd; Rosenthal, Michael; Griffith, Erin A.; Evans, Marion Willard

    2012-01-01

    Objective Methicillin-resistant Staphylococcus aureus (MRSA) is associated with difficult-to-treat infections and high levels of morbidity. Manual practitioners work in environments where MRSA is a common acquired infection. The purpose of this review is to provide a practical overview of MRSA as it applies to the manual therapy professions (eg, physical and occupational therapy, athletic training, chiropractic, osteopathy, massage, sports medicine) and to discuss how to identify and prevent MRSA infections in manual therapy work environments. Methods PubMed and CINAHL were searched from the beginning of their respective indexing years through June 2011 using the search terms MRSA, methicillin-resistant Staphylococcus aureus, and Staphylococcus aureus. Texts and authoritative Web sites were also reviewed. Pertinent articles from the authors' libraries were included if they were not already identified in the literature search. Articles were included if they were applicable to ambulatory health care environments in which manual therapists work or if the content of the article related to the clinical management of MRSA. Results Following information extraction, 95 citations were included in this review, to include 76 peer-reviewed journal articles, 16 government Web sites, and 3 textbooks. Information was organized into 10 clinically relevant categories for presentation. Information was organized into the following clinically relevant categories: microbiology, development of MRSA, risk factors for infection, clinical presentation, diagnostic tests, screening tests, reporting, treatment, prevention for patients and athletes, and prevention for health care workers. Conclusion Methicillin-resistant S aureus is a health risk in the community and to patients and athletes treated by manual therapists. Manual practitioners can play an essential role in recognizing MRSA infections and helping to control its transmission in the health care environment and the community

  8. Inhibition of methicillin resistant Staphylococcus aureus by a plasma needle

    NASA Astrophysics Data System (ADS)

    Miletić, Maja; Vuković, Dragana; Živanović, Irena; Dakić, Ivana; Soldatović, Ivan; Maletić, Dejan; Lazović, Saša; Malović, Gordana; Petrović, Zoran; Puač, Nevena

    2014-03-01

    In numerous recent papers plasma chemistry of non equilibrium plasma sources operating at atmospheric pressure has been linked to plasma medical effects including sterilization. In this paper we present a study of the effectiveness of an atmospheric pressure plasma source, known as plasma needle, in inhibition of the growth of biofilm produced by methicillin resistant Staphylococcus aureus (MRSA). Even at the lowest powers the biofilms formed by inoculi of MRSA of 104 and 105 CFU have been strongly affected by plasma and growth in biofilms was inhibited. The eradication of the already formed biofilm was not achieved and it is required to go to more effective sources.

  9. Community-Acquired Methicillin-Resistant "Staphylococcus aureus": Considerations for School Nurses

    ERIC Educational Resources Information Center

    Alex, Aniltta; Letizia, MariJo

    2007-01-01

    Methicillin-resistant "Staphylococcus aureus" (MRSA) is a disease-causing organism that has been present in hospital settings since the 1960s. However, a genetically distinct strain of MRSA, called community-acquired methicillin-resistant "Staphylococcus aureus" (CA-MRSA), has emerged in recent years in community settings among healthy…

  10. Colonization of Cimex lectularius with methicillin-resistant Staphylococcus aureus.

    PubMed

    Barbarin, Alexis M; Hu, Baofeng; Nachamkin, Irving; Levy, Michael Z

    2014-05-01

    A recent paper published by Lowe and Romney in Emerging Infectious Diseases titled, Bed bugs as Vectors for Drug-Resistant Bacteria has sparked a renewed interest in bed bug vector potential. We followed a pyrethroid resistant strain of the human bed bug (Cimex lectularius, L.) fed either human blood or human blood with added methicillin resistant Staphylococcus aureus (MRSA) for 9 days post-feeding. Results indicated that while the bed bug midgut is a hospitable environment for MRSA, the bacteria does not survive longer than 9 days within the midgut. Additionally, MRSA is not amplified within the midgut of the bug as the infection was cleared within 9 days. Due to the weekly feeding behaviours of bed bugs, these results suggest that bed bug transmission of MRSA is highly unlikely. PMID:24589308

  11. Prevalence of methicillin-resistant staphylococci in canine pyoderma cases in primary care veterinary practices in Canada: A preliminary study

    PubMed Central

    Joffe, Daniel; Goulding, Fiona; Langelier, Ken; Magyar, Gabor; McCurdy, Les; Milstein, Moe; Nielsen, Kia; Villemaire, Stephanie

    2015-01-01

    Pyoderma in dogs is most commonly caused by Staphylococcus spp., and significant emergence of methicillin resistance in staphylococcal pyoderma has been reported. This preliminary study of the prevalence of methicillin resistance in canine pyoderma cases in Canadian primary care veterinary practices revealed that methicillin-resistant Staphylococcus spp. were present in 12.1% of 149 staphylococcal positive skin culture cases. PMID:26483585

  12. Disc-diffusion and PCR detection of methicillin resistance in environmental airborne strains of Staphylococcus spp..

    PubMed

    Wolny-Koładka, Katarzyna; Lenart-Boroń, Anna; Kasprowicz, Andrzej

    2014-01-01

    The aim of this study was to assess the species composition of airborne Staphylococcus spp. in public premises, to determine the methicillin resistance of the isolates and the prevalence of mecA gene, determining resistance to β-lactams. In total 65 Staphylococcus strains were isolated from 54 sites. Four strains exhibited phenotypic methicillin resistance, while the presence of mecA gene was found in 11 strains. The results of both assays were compared, showing that the phenotypic tests revealed methicillin resistance only in 36% of the examined samples. This study revealed high species diversity among airborne Staphylococcus spp. population, which consists of multidrug resistant strains.

  13. Longitudinal Analysis of Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Carriage in Healthy Adolescents

    PubMed Central

    Wang, Shao-Chung; Chang, Hsin-Yu; Huang, Yhu-Chering

    2013-01-01

    To determine the long-term carriage patterns, strain relatedness, and incidence of subsequent infections among methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) carriers, we screened 154 high school students for nasal carriage of S. aureus on 8 occasions over 11 months. Persistent carriage was defined as a positive culture on ≥7 occasions. Two consecutive isolates from the same subject comprised a pair, and strain relatedness was determined for each pair by molecular typing. Of 1,232 nasal swab cultures obtained on 8 occasions, 323 (26.2%) were positive for S. aureus. Forty-five isolates (3.7%) were MRSA and 278 isolates (22.6%) were MSSA from 12 and 63 subjects, respectively. Thirty-five (77.8%) MRSA isolates harbored a type IV or VT staphylococcal chromosomal cassette mec element. Among the 154 subjects, 52 (33.8%) were intermittent (1 to 6 positive swabs) carriers. Persistent carriage was identified in 23 (14.9%) subjects, and the incidence was not significantly different for MRSA and MSSA carriers (3/12 [25%] versus 20/63 [31.7%]; P = 0.7449). The MRSA and MSSA isolates were composed of 33 and 215 strain pairs, respectively. Of them, an indistinguishable genotype was identified in 33 (100%) MRSA pairs and 173 (80.5%) MSSA pairs (P = 0.0053). Five subjects developed cellulitis, and the incidence of this was higher for MRSA carriers (2/12 [16.7%]) than for MSSA carriers (1/63 [1.58%]; P = 0.0632) and noncarriers (2/79 [2.56%]; P = 0.0828). In conclusion, the long-term carriage patterns for MRSA and MSSA in healthy individuals were similar. MRSA carriers were more likely to carry a single strain, with a trend toward a higher chance of developing cellulitis than for MSSA carriers. PMID:23678067

  14. Strategies for controlling methicillin-resistant Staphylococcus aureus in hospitals.

    PubMed

    Boyce, J M

    1995-07-01

    In areas where the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) is very low, aggressive strategies, which appear to have been effective, such as those used in the Netherlands and western Australia, may be feasible. In hospitals where MRSA is epidemic or highly endemic, less rigorous strategies are appropriate. However, which isolation techniques and barrier precautions are optimal is controversial. In addition, there is no consensus regarding the epidemiological importance of environmental contamination. Rapid detection of MRSA, prompt implementation of barrier precautions and prospective surveillance are essential components of a successful control programme. Eradicating nasal carriage of MRSA among patients and personnel can be useful during epidemics, but the cost-effectiveness of using this approach in hospitals where the prevalence of MRSA is low is unknown. Additional studies of this issue need to include surveillance for mupirocin-resistant strains.

  15. Community-associated methicillin-resistant Staphylococcus aureus, Iowa, USA.

    PubMed

    Van De Griend, Philip; Herwaldt, Loreen A; Alvis, Bret; DeMartino, Mary; Heilmann, Kristopher; Doern, Gary; Winokur, Patricia; Vonstein, Diana DeSalvo; Diekema, Daniel

    2009-10-01

    We performed antimicrobial drug susceptibility testing and molecular typing on invasive methicillin-resistant Staphylococcus aureus (MRSA) isolates (n = 1,666) submitted to the University of Iowa Hygienic Laboratory during 1999-2006 as part of a statewide surveillance system. All USA300 and USA400 isolates were resistant to

  16. Modulation of mecA Gene Expression by Essential Oil from Salvia sclarea and Synergism with Oxacillin in Methicillin Resistant Staphylococcus epidermidis Carrying Different Types of Staphylococcal Chromosomal Cassette mec

    PubMed Central

    Chovanová, Romana; Mikulášová, Mária; Vaverková, Štefánia

    2016-01-01

    The essential oil (EO) from Salvia sclarea was shown to increase the susceptibility of methicillin resistant Staphylococcus epidermidis (MRSE) isolates to oxacillin. The purpose of this study was to investigate the effect of EO from S. sclarea on expression of mecA gene of MRSE carrying different types of staphylococcal chromosomal cassette (SCCmec) and to evaluate potential synergistic effect of EO with oxacillin. Using real-time PCR we found that EO alone inhibited the expression of the resistant genes mecA, mecR1, and mecI and blaZ, blaR1, and blaI. The use of the combination of EO with oxacillin resulted in significantly inhibited expression of mecA gene in all tested strains with different types of SCCmec. Using time-kill assay and checkerboard assay we confirmed synergistic effect of EO from S. sclarea and oxacillin in MRSE. PMID:26880926

  17. Community-Associated Methicillin-Resistant Staphylococcus aureus Case Studies

    PubMed Central

    Sowash, Madeleine G.; Uhlemann, Anne-Catrin

    2014-01-01

    Over the past decade, the emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has changed the landscape of S. aureus infections around the globe. Initially recognized for its ability to cause disease in young and healthy individuals without healthcare exposures as well as for its distinct genotype and phenotype, this original description no longer fully encompasses the diversity of CA-MRSA as it continues to expand its niche. Using four case studies, we highlight a wide range of the clinical presentations and challenges of CA-MRSA. Based on these cases we further explore the globally polygenetic background of CA-MRSA with a special emphasis on generally less characterized populations. PMID:24085688

  18. Personal hygiene and methicillin-resistant Staphylococcus aureus infection.

    PubMed

    Turabelidze, George; Lin, Mei; Wolkoff, Barbara; Dodson, Douglas; Gladbach, Stephen; Zhu, Bao-Ping

    2006-03-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections outside the healthcare setting are an increasing concern. We conducted a case-control study to investigate an MRSA outbreak during 2002-2003 in a Missouri prison and focused on hygiene factors. Information on sociodemographic characteristics, medical history, and hygiene practices of study participants was collected by interview and medical record review. Logistic regression was used to evaluate MRSA infection in relation to hygiene factors individually and as a composite hygiene score; potential confounding factors were controlled. Selected MRSA isolates were analyzed by pulsed-field gel electrophoresis (PFGE). MRSA infection was significantly associated with a low composite hygiene score. Transmission among prison inmates appeared to be responsible for this outbreak. PFGE analysis showed that isolates were indistinguishable and associated with community-onset MRSA infections in other US prisons. Improving hygiene practices and environmental conditions may help prevent and interrupt future MRSA outbreaks in prison settings. PMID:16704779

  19. Evaluation of laboratory tests for detection of methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis.

    PubMed

    Coudron, P E; Jones, D L; Dalton, H P; Archer, G L

    1986-11-01

    Few studies evaluating susceptibility testing of methicillin-resistant staphylococci have included isolates of Staphylococcus epidermidis, a known pathogen in many types of serious infections. We tested 175 S. epidermidis and 95 Staphylococcus aureus isolates to determine the most sensitive procedures for detecting methicillin-resistant staphylococci. Reference procedures included agar dilution with methicillin and 4% NaCl in the agar and broth microdilution with methicillin and 2% NaCl in cation-supplemented Mueller-Hinton broth. After 24 h of incubation, the results from both methods correlated well and were within 1 log2 dilution for all isolates tested. Only one-half of all resistant isolates (92 of 183) were detected at 18 h by using the standard disk diffusion technique with 5-micrograms methicillin disks, and even fewer were detected with 10-micrograms methicillin disks and newly recommended zone-size criteria. However, the standard disk diffusion method with 4% NaCl in the agar increased the sensitivity and specificity for identification of the proper phenotype to greater than 92%. The spread plate and new spot techniques, both using agar with 4% NaCl, were also sensitive methods. Of 47 S. epidermidis isolates tested against oxacillin, 6 (13%) were oxacillin susceptible but methicillin resistant. Two automated systems, the Automicrobic system (Vitek Systems) and MicroScan (American MicroScan), as well as two broth screening systems available from Remel and Austin Biological Laboratories, failed to detect several resistant isolates, depending on the species.

  20. Evaluation of laboratory tests for detection of methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis.

    PubMed

    Coudron, P E; Jones, D L; Dalton, H P; Archer, G L

    1986-11-01

    Few studies evaluating susceptibility testing of methicillin-resistant staphylococci have included isolates of Staphylococcus epidermidis, a known pathogen in many types of serious infections. We tested 175 S. epidermidis and 95 Staphylococcus aureus isolates to determine the most sensitive procedures for detecting methicillin-resistant staphylococci. Reference procedures included agar dilution with methicillin and 4% NaCl in the agar and broth microdilution with methicillin and 2% NaCl in cation-supplemented Mueller-Hinton broth. After 24 h of incubation, the results from both methods correlated well and were within 1 log2 dilution for all isolates tested. Only one-half of all resistant isolates (92 of 183) were detected at 18 h by using the standard disk diffusion technique with 5-micrograms methicillin disks, and even fewer were detected with 10-micrograms methicillin disks and newly recommended zone-size criteria. However, the standard disk diffusion method with 4% NaCl in the agar increased the sensitivity and specificity for identification of the proper phenotype to greater than 92%. The spread plate and new spot techniques, both using agar with 4% NaCl, were also sensitive methods. Of 47 S. epidermidis isolates tested against oxacillin, 6 (13%) were oxacillin susceptible but methicillin resistant. Two automated systems, the Automicrobic system (Vitek Systems) and MicroScan (American MicroScan), as well as two broth screening systems available from Remel and Austin Biological Laboratories, failed to detect several resistant isolates, depending on the species. PMID:3639887

  1. Healthcare-Associated Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Kumari, Jyoti; Shenoy, Shalini M.; Baliga, Shrikala; Chakrapani, M.; Bhat, Gopalkrishna K.

    2016-01-01

    Objectives: Healthcare-associated methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen worldwide and its multidrug resistance is a major concern. This study aimed to determine the clinical characteristics and antibiotic susceptibility profile of healthcare-associated MRSA with emphasis on resistance to macrolide-lincosamide-streptogramin B (MLSB) phenotypes and vancomycin. Methods: This cross-sectional study was carried out between February 2014 and February 2015 across four tertiary care hospitals in Mangalore, South India. Healthcare-associated infections among 291 inpatients at these hospitals were identified according to the Centers for Disease Control and Prevention guidelines. Clinical specimens were collected based on infection type. S. aureus and MRSA isolates were identified and antibiotic susceptibility tests performed using the Kirby-Bauer disk diffusion method. The minimum inhibitory concentration of vancomycin was determined using the Agar dilution method and inducible clindamycin resistance was detected with a double-disk diffusion test (D-test). Results: Out of 291 healthcare-associated S. aureus cases, 88 were MRSA (30.2%). Of these, 54.6% were skin and soft tissue infections. All of the isolates were susceptible to teicoplanin and linezolid. Four MRSA isolates exhibited intermediate resistance to vancomycin (4.6%). Of the MRSA strains, 10 (11.4%) were constitutive MLSB phenotypes, 31 (35.2%) were inducible MLSB phenotypes and 14 (15.9%) were macrolide-streptogramin B phenotypes. Conclusion: Healthcare-associated MRSA multidrug resistance was alarmingly high. In routine antibiotic susceptibility testing, a D-test should always be performed if an isolate is resistant to erythromycin but susceptible to clindamycin. Determination of the minimum inhibitory concentration of vancomycin is necessary when treating patients with MRSA infections. PMID:27226908

  2. Investigational drugs to treat methicillin-resistant Staphylococcus aureus

    PubMed Central

    Vuong, Cuong; Yeh, Anthony J; Cheung, Gordon YC; Otto, Michael

    2016-01-01

    Introduction Staphylococcus aureus remains one of the leading causes of morbidity and mortality worldwide. This is to a large extent due to antibiotic-resistant strains, in particular methicillin-resistant S. aureus (MRSA). While the toll of invasive MRSA infections appears to decrease in U.S. hospitals, the rate of community-associated MRSA infections remains constant and there is a surge of MRSA in many other countries. This situation calls for continuing if not increased efforts to find novel strategies to combat MRSA infections. Areas covered This review will provide an overview of current investigational antibiotics in clinical development (up to phase II), and of therapeutic antibodies and alternative drugs against S. aureus in preclinical and clinical development, including a short description of the mechanism of action and a presentation of microbiological and clinical data. Expert opinion Increased recent antibiotic development efforts and results from pathogenesis research have led to several new antibiotics and alternative drugs, as well as a more informed selection of targets for vaccination efforts against MRSA. This developing portfolio of novel anti-staphylococcal drugs will hopefully provide us with additional and more efficient ways to combat MRSA infections in the near future and prevent us from running out of treatment options, even if new resistances arise. PMID:26536498

  3. Community-associated methicillin-resistant Staphylococcus aureus, Canada.

    PubMed

    Mulvey, Michael R; MacDougall, Laura; Cholin, Brenda; Horsman, Greg; Fidyk, Melanie; Woods, Shirley

    2005-06-01

    A total of 184 methicillin-resistant Staphylococcus aureus (MRSA) strains were collected from patients who sought treatment primarily for skin and soft tissue infections from January 1, 1999, to March 31, 2002, in east-central Saskatchewan, Canada. Molecular subtyping analysis using pulsed-field gel electrophoresis showed 2 major clusters. Cluster A (n = 55) was composed of a multidrug-resistant MRSA strain associated with a long-term care facility and was similar to the previously reported nosocomial Canadian epidemic strain labeled CMRSA-2. Cluster B (n = 125) was associated with cases identified at community health centers and was indistinguishable from a community-associated (CA)-MRSA strain identified previously in the United States (USA400). Cluster B remained susceptible to a number of classes of antimicrobial agents and harbored the lukF-PV and lukS-PV toxin genes. Over 50% of both clonal groups displayed high-level resistance to mupirocin. This is the first report of the USA400 strain harboring the lukF-PV and lukS-PV toxin genes in Canada.

  4. Rapid analysis of microbial systems using vibrational spectroscopy and supervised learning methods: application to the discrimination between methicillin-resistant and methicillin-susceptible Staphy

    NASA Astrophysics Data System (ADS)

    Goodacre, Royston; Rooney, Paul J.; Kell, Douglas B.

    1998-04-01

    FTIR spectra were obtained from 15 methicillin-resistant and 22 methicillin-susceptible Staphylococcus aureus strains using our DRASTIC approach. Cluster analysis showed that the major source of variation between the IR spectra was not due to their resistance or susceptibility to methicillin; indeed early studies suing pyrolysis mass spectrometry had shown that this unsupervised analysis gave information on the phage group of the bacteria. By contrast, artificial neural networks, based on a supervised learning, could be trained to recognize those aspects of the IR spectra which differentiated methicillin-resistant from methicillin- susceptible strains. These results give the first demonstration that the combination of FTIR with neural networks can provide a very rapid and accurate antibiotic susceptibility testing technique.

  5. [Investigation of reduced vancomycin susceptibility in methicillin-resistant staphylococci].

    PubMed

    Kuşcu, Ferit; Oztürk, Doğan Barış; Gürbüz, Yunus; Tütüncü, Emin Ediz; Sencan, Irfan; Gül, Serdar

    2011-04-01

    The first Staphylococcus aureus strain with reduced susceptibility to vancomycin was reported from Japan in 1996, and since then an increasing numbers of cases had been reported from various countries. Along with the unfeasibility in the identification of these strains with routine laboratory methods, the use of glycopeptid antibiotics in infections due to these strains may result in therapeutic failure. The aim of this study was to investigate the prevalence of vancomycin intermediate staphylococcus (VIS) and heterogenous VIS (hVIS) strains with the use of agar screening, macro E-test, and population analysis profile (PAP-UC; population analysis profile-area under the curve) methods. A total of 148 methicillin-resistant staphylococcus strains isolated from different clinical samples (48 tracheal aspirate, 48 blood, 39 wound swabs, eight urine, two cerebrospinal fluid, two pleural fluid, one catheter tip sample) between November 2007 and May 2009, were included in the study. Of the isolates 107 were identified as S.aureus and 41 were coagulase-negative staphylococci (CNS; 23 Staphylococcus epidermidis, six Staphylococcus haemolyticus, five Staphylococcus chromogenes, three Staphylococcus hominis and four others) by API Staph kit (bioMerieux, USA). Methicillin resistance has been determined by standard disk diffusion method with oxacillin (1 µg) and cefoxitin (30 µg) disks, according to "Clinical and Laboratory Standarts Institute (CLSI)" guidelines. For the identification of VIS and hVIS strains, brain-heart infusion agar plates containing 6 µg/ml vancomycin (BHI-V6) were used for screening. The suspected VISA/hVISA strains which grew in this agar were further tested by macro E-test and PAP-AUC methods. Total VIS and hVIS rates among the tested isolates, were found as 3.4% (5/148) and 1.4% (2/148), respectively. These rates for CNS strains were 9.8% (4/41) and 2.4% (1/41), and for S.aureus strains were 0.9% (1/107) ve 0.9% (1/107), respectively. In the

  6. Studies on clinical isolates of coagulase-negative staphylococci resistant to methicillin. Evidence of cross-resistance between methicillin and cephalothin.

    PubMed

    Hansen-Nord, M; Gahrn-Hansen, B; Siboni, K

    1988-02-01

    The in vitro susceptibility to cephalothin and cefuroxime of 195 isolates of methicillin-resistant coagulase-negative staphylococci was determined by the agar-diffusion test, using 7.5% NaCl-supplemented agar. The distribution of the inhibition zone diameters for isolates of S. epidermidis (S. biotype 1) as well as for S. haemolyticus (S. biotype 4) was trimodal. While 4% of the isolates were found susceptible to cefuroxime, 39% of the S. epidermidis/S. hominis (S. biotype 1) isolates and 34% of the S. haemolyticus (S. biotype 4) isolates were found susceptible to cephalothin by this method. Eight of these isolates (six S. epidermidis, two S. haemolyticus) were selected for susceptibility testing by the tube-dilution method, together with four isolates (three S. haemolyticus, one S. epidermidis) found resistant to cephalothin by the agar-diffusion test. The first-mentioned isolates were all found susceptible to cephalothin with MICs less than or equal to 2 micrograms/l, while the last-named all were resistant with MICs greater than or equal to 16 micrograms/ml. Population analyses revealed sub-populations of highly resistant bacteria in all methicillin-resistant isolates of S. epidermidis (S. biotype 1), as well as in all isolates of S. haemolyticus (S. biotype 4). We thus concluded that methicillin-resistance in isolates of coagulase-negative staphylococci implies resistance to cephalosporins and that the difference between S. epidermidis and S. haemolyticus as regards cephalosporin-susceptibility is quantitative and not qualitative. Eighty-nine per cent of the 195 methicillin-resistant isolates in this study were resistant to penicillin and at least one more antibiotic. We therefore think that resistance to penicillin and one or more non-beta-lactam antibiotics strongly suggests methicillin-resistance and that such isolates should be further tested on hypertonic media.

  7. Studies on clinical isolates of coagulase-negative staphylococci resistant to methicillin. Evidence of cross-resistance between methicillin and cephalothin.

    PubMed

    Hansen-Nord, M; Gahrn-Hansen, B; Siboni, K

    1988-02-01

    The in vitro susceptibility to cephalothin and cefuroxime of 195 isolates of methicillin-resistant coagulase-negative staphylococci was determined by the agar-diffusion test, using 7.5% NaCl-supplemented agar. The distribution of the inhibition zone diameters for isolates of S. epidermidis (S. biotype 1) as well as for S. haemolyticus (S. biotype 4) was trimodal. While 4% of the isolates were found susceptible to cefuroxime, 39% of the S. epidermidis/S. hominis (S. biotype 1) isolates and 34% of the S. haemolyticus (S. biotype 4) isolates were found susceptible to cephalothin by this method. Eight of these isolates (six S. epidermidis, two S. haemolyticus) were selected for susceptibility testing by the tube-dilution method, together with four isolates (three S. haemolyticus, one S. epidermidis) found resistant to cephalothin by the agar-diffusion test. The first-mentioned isolates were all found susceptible to cephalothin with MICs less than or equal to 2 micrograms/l, while the last-named all were resistant with MICs greater than or equal to 16 micrograms/ml. Population analyses revealed sub-populations of highly resistant bacteria in all methicillin-resistant isolates of S. epidermidis (S. biotype 1), as well as in all isolates of S. haemolyticus (S. biotype 4). We thus concluded that methicillin-resistance in isolates of coagulase-negative staphylococci implies resistance to cephalosporins and that the difference between S. epidermidis and S. haemolyticus as regards cephalosporin-susceptibility is quantitative and not qualitative. Eighty-nine per cent of the 195 methicillin-resistant isolates in this study were resistant to penicillin and at least one more antibiotic. We therefore think that resistance to penicillin and one or more non-beta-lactam antibiotics strongly suggests methicillin-resistance and that such isolates should be further tested on hypertonic media. PMID:3345258

  8. Transduction of Methicillin Resistance in Staphylococcus aureus Dependent on an Unusual Specificity of the Recipient Strain

    PubMed Central

    Cohen, Sidney; Sweeney, Helen M.

    1970-01-01

    Resistance to methicillin was transduced by phage 80 or 53 from two naturally occurring methicillin-resistant strains of Staphylococcus aureus to methicillin-susceptible recipient strains at frequencies of 10−7 to 10−9. Ultraviolet irradiation of transducing phage and posttransductional incubation at 30 C were essential for useful frequencies of transduction. Effectiveness as a recipient for this transduction was highly specific. Strain NCTC 8325 (PS47) in its native state was an ineffective recipient but became effective after it had received by transduction one of several penicillinase plasmids. This acquired effectiveness was retained in most cases after elimination of the plasmid by ethidium bromide treatment. Like the donor strain, the progeny were heterogeneous in the degree of their resistance to methicillin, which was expressed by a higher proportion of cells as the temperature of incubation was lowered from 37 to 30 C. Separate transductants varied widely in the degree of resistance acquired by transduction. Methicillin resistance was stable in the donor and transductant strains. We favored the interpretation that methicillin resistance in our strains was determined by a single chromosomal gene, although the possibility that it was determined by two or more closely linked genes could not be excluded. PMID:16559089

  9. Identification of methicillin-resistant Staphylococcus aureus using an integrated and modular microfluidic system.

    PubMed

    Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Soper, Steven A

    2013-02-21

    Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital-acquired (HA-MRSA) infection worldwide. As a result, the rapid and specific detection of MRSA is crucial not only for early prevention of disease spread, but also for the effective treatment of these infections. We report here an integrated modular-based microfluidic system for MRSA identification, which can carry out the multi-step assay used for MRSA identification in a single disposable fluidic cartridge. The multi-step assay included PCR amplification of the mecA gene harboring methicillin resistance loci that can provide information on drug susceptibility, ligase detection reaction (LDR) to generate fluorescent ligation products appended with a zip-code complement that directs the ligation product to a particular address on a universal array containing zip-code probes and a universal DNA array, which consisted of a planar waveguide for evanescent excitation. The fluidic cartridge design was based on a modular format, in which certain steps of the molecular processing pipeline were poised on a module made from a thermoplastic. The cartridge was comprised of a module interconnected to a fluidic motherboard configured in a 3-dimensional network; the motherboard was made from polycarbonate, PC, and was used for PCR and LDR, while the module was made from poly(methylmethacrylate), PMMA, and contained an air-embedded waveguide serving as the support for the universal array. Fluid handling, thermal management and optical readout hardware were situated off-chip and configured into a small footprint instrument. In this work, the cartridge was used to carry out a multiplexed PCR/LDR coupled with the universal array allowed for simultaneous detection of five genes that encode for 16S ribosomal RNA (SG16S), protein A (spa), the femA protein of S. epidermidis (femA), the virulence factor of Panton-Valentine leukocidin (PVL) and the gene that confers methicillin resistance (mecA). Results

  10. Identification of methicillin-resistant Staphylococcus aureus using an integrated and modular microfluidic system.

    PubMed

    Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Soper, Steven A

    2013-02-21

    Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital-acquired (HA-MRSA) infection worldwide. As a result, the rapid and specific detection of MRSA is crucial not only for early prevention of disease spread, but also for the effective treatment of these infections. We report here an integrated modular-based microfluidic system for MRSA identification, which can carry out the multi-step assay used for MRSA identification in a single disposable fluidic cartridge. The multi-step assay included PCR amplification of the mecA gene harboring methicillin resistance loci that can provide information on drug susceptibility, ligase detection reaction (LDR) to generate fluorescent ligation products appended with a zip-code complement that directs the ligation product to a particular address on a universal array containing zip-code probes and a universal DNA array, which consisted of a planar waveguide for evanescent excitation. The fluidic cartridge design was based on a modular format, in which certain steps of the molecular processing pipeline were poised on a module made from a thermoplastic. The cartridge was comprised of a module interconnected to a fluidic motherboard configured in a 3-dimensional network; the motherboard was made from polycarbonate, PC, and was used for PCR and LDR, while the module was made from poly(methylmethacrylate), PMMA, and contained an air-embedded waveguide serving as the support for the universal array. Fluid handling, thermal management and optical readout hardware were situated off-chip and configured into a small footprint instrument. In this work, the cartridge was used to carry out a multiplexed PCR/LDR coupled with the universal array allowed for simultaneous detection of five genes that encode for 16S ribosomal RNA (SG16S), protein A (spa), the femA protein of S. epidermidis (femA), the virulence factor of Panton-Valentine leukocidin (PVL) and the gene that confers methicillin resistance (mecA). Results

  11. Transmission Dynamics of Methicillin-Resistant Staphylococcus aureus in Pigs

    PubMed Central

    Crombé, Florence; Argudín, M. Angeles; Vanderhaeghen, Wannes; Hermans, Katleen; Haesebrouck, Freddy; Butaye, Patrick

    2013-01-01

    From the mid-2000s on, numerous studies have shown that methicillin-resistant Staphylococcus aureus (MRSA), renowned as human pathogen, has a reservoir in pigs and other livestock. In Europe and North America, clonal complex (CC) 398 appears to be the predominant lineage involved. Especially worrisome is its capacity to contaminate humans in close contact with affected animals. Indeed, the typical multi-resistant phenotype of MRSA CC398 and its observed ability of easily acquiring genetic material suggests that MRSA CC398 strains with an increased virulence potential may emerge, for which few therapeutic options would remain. This questions the need to implement interventions to control the presence and spread of MRSA CC398 among pigs. MRSA CC398 shows a high but not fully understood transmission potential in the pig population and is able to persist within that population. Although direct contact is probably the main route for MRSA transmission between pigs, also environmental contamination, the presence of other livestock, the herd size, and farm management are factors that may be involved in the dissemination of MRSA CC398. The current review aims at summarizing the research that has so far been done on the transmission dynamics and risk factors for introduction and persistence of MRSA CC398 in farms. PMID:23518663

  12. Antimicrobial (Drug) Resistance: Methicillin-Resistant Staphylococcus aureus (MRSA)

    MedlinePlus

    ... NIAID invests in basic research to understand the biology of microbes, their behavior, and how drug resistance ... Nucleotide Polymorphism Phylogenetics & Ontology Proteomics & Protein Analysis Systems Biology Data Portals Software Applications BCBB Mobyle Interface Designer ( ...

  13. Ultraviolet germicidal irradiation susceptibility of methicillin-resistant Staphylococcus aureus compared with methicillin-susceptible S. aureus.

    PubMed

    Green, Christopher F; Elbe, Laura A; Neal, Tyler D; Lowe, John J; Gibbs, Shawn G

    2015-11-01

    Antibiotic misuse and overuse in both the healthcare and agricultural fields have dramatically increased the prevalence of antibiotic resistance in human pathogens. Two strains of methicillin-resistant Staphylococcus aureus (MRSA) (ATCC 43330 and a wild-type) and 1 strain of methicillin-susceptible S. aureus (ATCC 25923) were challenged (9 runs in triplicate) in a preliminary study with ultraviolet germicidal irradiation (UVGI) doses ranging from 0.25 to 3.00 mJ/cm(2). The mean percent kill was calculated for each strain when compared with the control plates (no exposure to UVGI). Then, each strain was challenged (22 runs in triplicate) with UVGI doses of 2.00, 2.50, and 3.00 mJ/cm(2). The results suggest a difference between the doses required to disinfect surfaces with each strain. Assuming a standard error rate of α = 0.05, there was a significant difference in variance between the MRSA (ATCC 43330 and wild type) strains and the S. aureus (ATCC 25923) methicillin-susceptible strain.

  14. Ultraviolet germicidal irradiation susceptibility of methicillin-resistant Staphylococcus aureus compared with methicillin-susceptible S. aureus.

    PubMed

    Green, Christopher F; Elbe, Laura A; Neal, Tyler D; Lowe, John J; Gibbs, Shawn G

    2015-11-01

    Antibiotic misuse and overuse in both the healthcare and agricultural fields have dramatically increased the prevalence of antibiotic resistance in human pathogens. Two strains of methicillin-resistant Staphylococcus aureus (MRSA) (ATCC 43330 and a wild-type) and 1 strain of methicillin-susceptible S. aureus (ATCC 25923) were challenged (9 runs in triplicate) in a preliminary study with ultraviolet germicidal irradiation (UVGI) doses ranging from 0.25 to 3.00 mJ/cm(2). The mean percent kill was calculated for each strain when compared with the control plates (no exposure to UVGI). Then, each strain was challenged (22 runs in triplicate) with UVGI doses of 2.00, 2.50, and 3.00 mJ/cm(2). The results suggest a difference between the doses required to disinfect surfaces with each strain. Assuming a standard error rate of α = 0.05, there was a significant difference in variance between the MRSA (ATCC 43330 and wild type) strains and the S. aureus (ATCC 25923) methicillin-susceptible strain. PMID:26376157

  15. Methicillin resistant S. aureus in human and bovine mastitis.

    PubMed

    Holmes, Mark A; Zadoks, Ruth N

    2011-12-01

    Staphylococcus aureus is a ubiquitous organism that causes a variety of diseases including mastitis in cattle and humans. High-level resistance of S. aureus to β-lactams conferred by a mecA gene encoding a modified penicillin binding protein (PBP2a) was first observed in the early 1960's. These methicillin resistant S. aureus (MRSA) have been responsible for both hospital acquired infections (HA-MRSA) and, more recently, community acquired MRSA (CA-MRSA). A small number of human MRSA mastitis cases and outbreaks in maternity or neonatal units have been reported which are generally the result of CA-MRSA. The establishment of the sequence type 398 (ST398) in farm animals, primarily pigs, in the early 2000's has provided a reservoir of infection for humans and dairy cattle, particularly in continental Europe, described as livestock-associated MRSA (LA-MRSA). Prior to the emergence of ST398 there were sporadic reports of MRSA in bovine milk and cases of mastitis, often caused by strains from human associated lineages. Subsequently, there have been several reports describing bovine udder infections caused by ST-398 MRSA. Recently, another group of LA-MRSA strains was discovered in humans and dairy cattle in Europe. This group carries a divergent mecA gene and includes a number of S. aureus lineages (CC130, ST425, and CC1943) that were hitherto thought to be bovine-specific but are now also found as carriage or clinical isolates in humans. The emergence of MRSA in dairy cattle may be associated with contact with other host species, as in the case of ST398, or with the exchange of genetic material between S. aureus and coagulase negative Staphylococcus species, which are the most common species associated with bovine intramammary infections and commonly carry antimicrobial resistance determinants.

  16. Clinical Outcomes with Rapid Detection of Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Isolates from Routine Blood Cultures

    PubMed Central

    Nicolsen, Nicole C.; LeCroy, Nicholas; Alby, Kevin; Laux, Jeffrey; Lin, Feng-Chang; Daniels, Lindsay; Weber, David J.

    2013-01-01

    Staphylococcus aureus is a common cause of bacteremia, with a substantial impact on morbidity and mortality. Because of increasing rates of methicillin-resistant Staphylococcus aureus, vancomycin has become the standard empirical therapy. However, beta-lactam antibiotics remain the best treatment choice for methicillin-susceptible strains. Placing patients quickly on the optimal therapy is one goal of antimicrobial stewardship. This retrospective, observational, single-center study compared 33 control patients utilizing only traditional full-susceptibility methodology to 22 case patients utilizing rapid methodology with CHROMagar medium to detect and differentiate methicillin-resistant and methicillin-susceptible Staphylococcus aureus strains hours before full susceptibilities were reported. The time to targeted therapy was statistically significantly different between control patients (mean, 56.5 ± 13.6 h) and case patients (44.3 ± 17.9 h) (P = 0.006). Intensive care unit status, time of day results emerged, and patient age did not make a difference in time to targeted therapy, either singly or in combination. Neither length of stay (P = 0.61) nor survival (P = 1.0) was statistically significantly different. Rapid testing yielded a significant result, with a difference of 12.2 h to targeted therapy. However, there is still room for improvement, as the difference in time to susceptibility test result between the full traditional methodology and CHROMagar was even larger (26.5 h). This study supports the hypothesis that rapid testing plays a role in antimicrobial stewardship by getting patients on targeted therapy faster. PMID:24088861

  17. Methicillin-Resistant Staphylococcus aureus Adaptation to Human Keratinocytes

    PubMed Central

    Soong, Grace; Paulino, Franklin; Wachtel, Sarah; Parker, Dane; Wickersham, Matthew; Zhang, Dongni; Brown, Armand; Lauren, Christine; Dowd, Margaret; West, Emily; Horst, Basil; Planet, Paul

    2015-01-01

    ABSTRACT Skin is the most common site of Staphylococcus aureus infection. While most of these infections are self-limited, recurrent infections are common. Keratinocytes and recruited immune cells participate in skin defense against infection. We postulated that S. aureus is able to adapt to the milieu within human keratinocytes to avoid keratinocyte-mediated clearance. From a collection of S. aureus isolated from chronically infected patients with atopic dermatitis, we noted 22% had an agr mutant-like phenotype. Using several models of human skin infection, we demonstrate that toxin-deficient, agr mutants of methicillin-resistant S. aureus (MRSA) USA300 are able to persist within keratinocytes by stimulating autophagy and evading caspase-1 and inflammasome activation. MRSA infection induced keratinocyte autophagy, as evidenced by galectin-8 and LC3 accumulation. Autophagy promoted the degradation of inflammasome components and facilitated staphylococcal survival. The recovery of more than 58% agr or RNAIII mutants (P < 0.0001) of an inoculum of wild-type (WT) MRSA from within wortmannin-treated keratinocytes compared to control keratinocytes reflected the survival advantage for mutants no longer expressing agr-dependent toxins. Our results illustrate the dynamic interplay between S. aureus and keratinocytes that can result in the selection of mutants that have adapted specifically to evade keratinocyte-mediated clearance mechanisms. PMID:25900653

  18. Discovery of Antivirulence Agents against Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Khodaverdian, Varandt; Pesho, Michelle; Truitt, Barbara; Bollinger, Lucy; Patel, Parita; Nithianantham, Stanley; Yu, Guanping; Delaney, Elizabeth; Jankowsky, Eckhard

    2013-01-01

    Antivirulence agents inhibit the production of disease-causing virulence factors but are neither bacteriostatic nor bactericidal. Antivirulence agents against methicillin-resistant Staphylococcus aureus (MRSA) strain USA300, the most widespread community-associated MRSA strain in the United States, were discovered by virtual screening against the response regulator AgrA, which acts as a transcription factor for the expression of several of the most prominent S. aureus toxins and virulence factors involved in pathogenesis. Virtual screening was followed by similarity searches in the databases of commercial vendors. The small-molecule compounds discovered inhibit the production of the toxins alpha-hemolysin and phenol-soluble modulin α in a dose-dependent manner without inhibiting bacterial growth. These antivirulence agents are small-molecule biaryl compounds in which the aromatic rings either are fused or are separated by a short linker. One of these compounds is the FDA-approved nonsteroidal anti-inflammatory drug diflunisal. This represents a new use for an old drug. Antivirulence agents might be useful in prophylaxis and as adjuvants in antibiotic therapy for MRSA infections. PMID:23689713

  19. Origins of Community Strains of Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Charlebois, Edwin D.; Perdreau-Remington, Françoise; Kreiswirth, Barry; Bangsberg, David R.; Ciccarone, Daniel; Diep, Binh A.; Ng, Valerie L.; Chansky, Kimberly; Edlin, Brian; Chambers, Henry F.

    2008-01-01

    To characterize methicillin-resistant Staphylococcus aureus (MRSA) strains circulating in the community, we identified predictors of isolating community MRSA and genotyped a sample of MRSA collected from a community-based, high-risk population. Computerized databases of the Community Health Network of San Francisco and the Clinical Microbiology Laboratory were searched electronically for the years 1992–1999 to identify community-onset infections caused by MRSA. Sequential analyses were performed to identify predictors of MRSA strains. The majority (58%) of infections were caused by strains traceable to the hospital or to long-term care facilities. Injection drug use was associated with infections that were not associated with health care settings. Genotypes for 20 of 35 MRSA isolates recovered from injection drug users did not match any of >600 genotypes of clinical isolates. In a nonoutbreak setting, the hospital was the main source of community MRSA; however, the presence of genetically distinct and diverse MRSA strains indicates MRSA strains now also originate from the community. PMID:15206052

  20. Community-associated methicillin-resistant Staphylococcus aureus

    PubMed Central

    DeLeo, Frank R.; Otto, Michael; Kreiswirth, Barry N.; Chambers, Henry F.

    2012-01-01

    Summary Methicillin-resistant Staphylococcus aureus (MRSA) is endemic in hospitals worldwide and a significant cause of morbidity and mortality. Healthcare-associated MRSA infections occur in individuals with predisposing risk factors for disease, such as surgery or presence of an indwelling medical device. By contrast, community-associated MRSA (CA-MRSA) infections often occur in otherwise healthy individuals who lack such risk factors. In addition, CA-MRSA infections are epidemic in some countries. These observations suggest that CA-MRSA strains are more virulent and transmissible than traditional hospital-associated MRSA strains. Relatively limited treatment options for CA-MRSA infections compound the problem of enhanced virulence and transmission. Although progress has been made toward understanding emergence of CA-MRSA, virulence, and treatment of infections, our knowledge in these areas remains incomplete. Here were review the most current knowledge in these areas and provide perspective on future outlook for prophylaxis and/or new therapies for CA-MRSA infections. PMID:20206987

  1. Community-Acquired Methicillin-Resistant Pyogenic Liver Abscess

    PubMed Central

    Cherian, Joel; Singh, Rahul; Varma, Muralidhar; Vidyasagar, Sudha; Mukhopadhyay, Chiranjay

    2016-01-01

    Pyogenic liver abscesses are rare with an incidence of 0.5% to 0.8% and are mostly due to hepatobiliary causes (40% to 60%). Most are polymicrobial with less than 10% being caused by Staphylococcus aureus. Of these, few are caused by methicillin-resistant Staphylococcus aureus (MRSA) and fewer still by a community-acquired strain. Here we present a case study of a patient with a community-acquired MRSA liver abscess. The patient presented with fever since 1 month and tender hepatomegaly. Blood tests revealed elevated levels of alkaline phosphatase, C-reactive protein, erythrocyte sedimentation rate, and neutrophilic leukocytosis. Blood cultures were sterile. Ultrasound of the abdomen showed multiple abscesses, from which pus was drained and MRSA isolated. Computed tomography of the abdomen did not show any source of infection, and an amebic serology was negative. The patient was started on vancomycin for 2 weeks, following which he became afebrile and was discharged on oral linezolid for 4 more weeks. Normally a liver abscess is treated empirically with ceftriaxone for pyogenic liver abscess and metronidazole for amebic liver abscess. However, if the patient has risk factors for a Staphylococcal infection, it is imperative that antibiotics covering gram-positive organisms be added while waiting for culture reports. PMID:27540556

  2. Methicillin-resistant Staphylococcus aureus in horses and horse personnel.

    PubMed

    Weese, J Scott

    2004-12-01

    Fortunately, MRSA infection and colonization are currently uncommon in veterinary medicine. Nevertheless, the increasing reports of the occurrence of MRSA infection in horses, veterinarians, and equine personnel dictate that serious consideration be given to the control of this pathogen in veterinary hospitals as well as in the equine community. It is unclear whether extrapolation from human hospitals and people in the community is appropriate; however, given the rapid increase in nosocomial MRSA in human hospitals and the recent shift of certain clones of MRSA into the community, it would be unwise to ignore this potential pathogen. If equine MRSA did, indeed, originate in the human population, complete eradication in the equine population is unlikely, regardless of the prevalence of infection in horses and the intensity of infection control measures, without concurrent eradication of MRSA in the human population, which is surely an impossible feat. Early institution of appropriate surveillance and other infection control measures should be used to attempt to limit the impact of MRSA in veterinary medicine, however. It has been stated, "The time to act is now, before the prevalence of MRSA in the community begins to rise and we end up with 50% of the community strains becoming methicillin-resistant". This statement was directed at control of MRSA in people; however, it is equally relevant in the veterinary context and should receive strong consideration. PMID:15519821

  3. Effects of bacteriocins on methicillin-resistant Staphylococcus aureus biofilm.

    PubMed

    Okuda, Ken-ichi; Zendo, Takeshi; Sugimoto, Shinya; Iwase, Tadayuki; Tajima, Akiko; Yamada, Satomi; Sonomoto, Kenji; Mizunoe, Yoshimitsu

    2013-11-01

    Control of biofilms formed by microbial pathogens is an important subject for medical researchers, since the development of biofilms on foreign-body surfaces often causes biofilm-associated infections in patients with indwelling medical devices. The present study examined the effects of different kinds of bacteriocins, which are ribosomally synthesized antimicrobial peptides produced by certain bacteria, on biofilms formed by a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA). The activities and modes of action of three bacteriocins with different structures (nisin A, lacticin Q, and nukacin ISK-1) were evaluated. Vancomycin, a glycopeptide antibiotic used in the treatment of MRSA infections, showed bactericidal activity against planktonic cells but not against biofilm cells. Among the tested bacteriocins, nisin A showed the highest bactericidal activity against both planktonic cells and biofilm cells. Lacticin Q also showed bactericidal activity against both planktonic cells and biofilm cells, but its activity against biofilm cells was significantly lower than that of nisin A. Nukacin ISK-1 showed bacteriostatic activity against planktonic cells and did not show bactericidal activity against biofilm cells. Mode-of-action studies indicated that pore formation leading to ATP efflux is important for the bactericidal activity against biofilm cells. Our results suggest that bacteriocins that form stable pores on biofilm cells are highly potent for the treatment of MRSA biofilm infections. PMID:23979748

  4. Evaluation for a novel methicillin resistance (mecC) homologue in methicillin-resistant Staphylococcus aureus isolates obtained from injured military personnel.

    PubMed

    Ganesan, Anuradha; Crawford, Katrina; Mende, Katrin; Murray, Clinton K; Lloyd, Bradley; Ellis, Michael; Tribble, David R; Weintrob, Amy C

    2013-09-01

    A total of 102 methicillin-resistant Staphylococcus aureus (MRSA) isolates collected from 50 injured service members (June 2009 to December 2011) at U.S. military treatment facilities were analyzed for the conventional mecA gene and mecC homologue by using standard PCR-based methods. The prevalence of the mecC homologue was zero.

  5. Performance of CHROMagar MRSA Medium for Detection of Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Diederen, Bram; van Duijn, Inge; van Belkum, Alex; Willemse, Piet; van Keulen, Peter; Kluytmans, Jan

    2005-01-01

    CHROMagar MRSA was evaluated for its ability to identify methicillin-resistant Staphylococcus aureus (MRSA). A well-defined collection consisting of 216 MRSA strains and 241 methicillin-susceptible Staphylococcus aureus isolates was used. The sensitivity of CHROMagar MRSA after 24 h of incubation was 95.4%, increasing to 100% after 48 h. The specificity was already 100% after 24 h. PMID:15815020

  6. Treatment of methicillin-resistant Staphylococcus aureus: vancomycin and beyond.

    PubMed

    Holmes, Natasha E; Tong, Steven Y C; Davis, Joshua S; van Hal, Sebastiaan J

    2015-02-01

    There has been a welcome increase in the number of agents available for the treatment of methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin remains an acceptable treatment option, with moves toward individualized dosing to a pharmacokinetic/pharmacodynamic (PK/PD) target. Numerous practicalities, however, would need to be resolved before implementation. Lipoglycopeptides as a class show excellent in vitro potency. Their long half-lives and complex PKs may preclude these agents being used in critically ill patients. Anti-MRSA cephalosporins provide great promise in the treatment of MRSA. These agents, despite broad-spectrum activity, should be reserved for patients with MRSA infections as it is likely that usage will be associated with increased rates of resistance. Daptomycin is currently the only antibiotic to have shown noninferiority to vancomycin in the treatment of MRSA bacteremia. The results of an open-labeled trial to address the superiority of daptomycin compared with vancomycin in reduced vancomycin susceptibility infections are eagerly anticipated. No drug to date has shown superiority to vancomycin in the treatment of MRSA infections with the possible exception of linezolid in hospital-acquired pneumonia (HAP), making linezolid an important option in the treatment of MRSA-proven HAP. Whether these strengths and features are agent or class specific are unclear but will likely be answered with the marketing of tedizolid. There are insufficient data to recommend either quinupristin/dalfopristin or tigecycline, as first line in the treatment of severe MRSA infections. These agents however remain options in patients with no other alternatives. PMID:25643268

  7. Methicillin-resistant Staphylococcus sp. colonizing health care workers of a cancer hospital

    PubMed Central

    Costa, Dayane de Melo; Kipnis, André; Leão-Vasconcelos, Lara Stefânia Netto de Oliveira; Rocha-Vilefort, Larissa Oliveira; Telles, Sheila Araújo; André, Maria Cláudia Dantas Porfírio Borges; Tipple, Anaclara Ferreira Veiga; Lima, Ana Beatriz Mori; Ribeiro, Nádia Ferreira Gonçalves; Pereira, Mayara Regina; Prado-Palos, Marinésia Aparecida

    2014-01-01

    The aim of the study was to analyze epidemiological and microbiological aspects of oral colonization by methicillin-resistant Staphylococcus of health care workers in a cancer hospital. Interview and saliva sampling were performed with 149 health care workers. Antimicrobial resistance was determined by disk diffusion and minimum inhibitory concentration. Polymerase Chain Reaction, Internal Transcribed Spacer-Polymerase Chain Reaction and Pulsed Field Gel Electrophoresis were performed for genotypic characterization of methicillin-resistant Staphylococcus. Risk factors were determined by logistic regression. Methicillin-resistant Staphylococcus colonization prevalence was 19.5%, denture wearing (p = 0.03), habit of nail biting (p = 0.04) and preparation and administration of antimicrobial (p = 0.04) were risk factors identified. All methicillin-resistant Staphylococcus were S. epidermidis, 94.4% of them had mecA gene. Closely related and indistinguishable methicillin-resistant S. epidermidis were detected. These results highlight that HCWs which have contact with patient at high risk for developing infections were identified as colonized by MRSE in the oral cavity, reinforcing this cavity as a reservoir of these bacteria and the risk to themselves and patients safety, because these microorganisms may be spread by coughing and talking. PMID:25477910

  8. Methicillin-resistant Staphylococcus sp. colonizing health care workers of a cancer hospital.

    PubMed

    Costa, Dayane de Melo; Kipnis, André; Leão-Vasconcelos, Lara Stefânia Netto de Oliveira; Rocha-Vilefort, Larissa Oliveira; Telles, Sheila Araújo; André, Maria Cláudia Dantas Porfírio Borges; Tipple, Anaclara Ferreira Veiga; Lima, Ana Beatriz Mori; Ribeiro, Nádia Ferreira Gonçalves; Pereira, Mayara Regina; Prado-Palos, Marinésia Aparecida

    2014-01-01

    The aim of the study was to analyze epidemiological and microbiological aspects of oral colonization by methicillin-resistant Staphylococcus of health care workers in a cancer hospital. Interview and saliva sampling were performed with 149 health care workers. Antimicrobial resistance was determined by disk diffusion and minimum inhibitory concentration. Polymerase Chain Reaction, Internal Transcribed Spacer-Polymerase Chain Reaction and Pulsed Field Gel Electrophoresis were performed for genotypic characterization of methicillin-resistant Staphylococcus. Risk factors were determined by logistic regression. Methicillin-resistant Staphylococcus colonization prevalence was 19.5%, denture wearing (p = 0.03), habit of nail biting (p = 0.04) and preparation and administration of antimicrobial (p = 0.04) were risk factors identified. All methicillin-resistant Staphylococcus were S. epidermidis, 94.4% of them had mecA gene. Closely related and indistinguishable methicillin-resistant S. epidermidis were detected. These results highlight that HCWs which have contact with patient at high risk for developing infections were identified as colonized by MRSE in the oral cavity, reinforcing this cavity as a reservoir of these bacteria and the risk to themselves and patients safety, because these microorganisms may be spread by coughing and talking. PMID:25477910

  9. Methicillin resistant Staphylococcus aureus (MRSA) infection in cystic fibrosis

    PubMed Central

    Miall, L; McGinley, N; Brownlee, K; Conway, S

    2001-01-01

    BACKGROUND—Methicillin resistant Staphylococcus aureus (MRSA) infection is increasingly found in patients with cystic fibrosis (CF).
AIMS—To determine whether MRSA infection has a deleterious effect on the clinical status of children with CF.
METHODS—Children with MRSA in respiratory cultures during a seven year period were identified and compared with controls matched for age, sex, and respiratory function. Respiratory function tests, anthropometric data, Shwachman-Kulczycki score, Northern chest x ray score, intravenous and nebulised antibiotic therapy, and steroid therapy were compared one year before and one year after MRSA infection.
RESULTS—From a clinic population of 300, 10 children had positive sputum or cough swab cultures for MRSA. Prevalence rose from 0 in 1992-1994 to 7 in 1998. Eighteen controls were identified. Children with MRSA showed significant worsening of height standard deviation scores and required twice as many courses of intravenous antibiotics as controls after one year. They had significantly worse chest x ray scores at the time of the first MRSA isolate and one year later, but showed no increase in the rate of decline in chest x ray appearance. There was a trend towards lower FEV1 and FEF25-75 in children with MRSA. There were no significant differences between the two groups with respect to change in weight, body mass index, or Shwachman score. There was no significant difference in prior use of steroids or nebulised antibiotics.
CONCLUSION—MRSA infection in children with CF does not significantly affect respiratory function, but may have an adverse effect on growth. Children with MRSA require significantly more courses of intravenous antibiotics and have a worse chest x ray appearance than controls.

 PMID:11159295

  10. Methicillin-resistant Staphylococcus aureus infection in vascular surgical patients.

    PubMed Central

    Murphy, G. J.; Pararajasingam, R.; Nasim, A.; Dennis, M. J.; Sayers, R. D.

    2001-01-01

    BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) infection is emerging as a major problem in vascular surgical practice. The aim of this study was to review the management of patients with MRSA infection complicating vascular surgical operations. METHODS: Data were obtained from the vascular audit, case notes, intensive therapy unit (ITU) notes, high dependency unit (HDU) notes and microbiological records of patients who underwent either arterial reconstruction (n = 464) or limb amputation (n = 110) between April 1994 and October 1998. RESULTS: Forty-nine vascular surgical patients developed clinical MRSA infection (9%). Clinical MRSA infection in patients who had undergone aorto-iliac reconstruction (n = 18) was associated with a 56% mortality (n = 10) and the most common infections were bacteraemia (55%) and pneumonia (50%). MRSA infection occurred in 17 patients who had undergone infra-inguinal bypass and was associated with a 29% mortality (n = 5). The most common site of MRSA infection was the groin wound (76%) leading to anastomotic dehiscence and death in one patient (11%) and necessitating wound debridement in 4 patients (22%). MRSA infection of the groin wound in the presence of a prosthetic graft (n = 3) led to anastomotic dehiscence in 2 patients, and graft excision in 2 patients. Similar complications were not observed in the presence of an underlying autogeneous long saphenous vein graft (n = 16). MRSA infection following major lower limb amputation (n = 14) was associated with death in 5 patients (36%). Wound infection in 10 amputees (71%) led to revision of the amputation to a higher level in 2 (14%) and wound debridement in 2 (14%). CONCLUSIONS: MRSA infection has a high mortality in vascular surgical patients in general, and following aorto-iliac reconstruction in particular. Autogeneous vein may confer some protection against local complications following groin wound infection. Strategies aimed at reducing the incidence of infection

  11. Complete Genome Sequences of Three Important Methicillin-Resistant Clinical Isolates of Staphylococcus pseudintermedius

    PubMed Central

    Riley, Matthew C.; Bemis, David A.

    2016-01-01

    We report the first complete genome sequences of three predominant clones (ST68, ST71, and ST84) of methicillin-resistant Staphylococcus pseudintermedius in North America. All strains were isolated from canine infections and have different SCCmec elements and antibiotic resistance gene patterns. PMID:27795289

  12. Staphylococcus haemolyticus as an important hospital pathogen and carrier of methicillin resistance genes.

    PubMed

    Barros, E M; Ceotto, H; Bastos, M C F; Dos Santos, K R N; Giambiagi-Demarval, M

    2012-01-01

    Phenotypic and molecular methods were used to characterize the antibiotic resistance of 64 clinical isolates of Staphylococcus haemolyticus. By PCR of the mecA gene, 87% were found to be methicillin resistant. Approximately 55% harbored staphylococcal cassette chromosome mec element (SCCmec) type V, and only one SCCmec type IV. Many isolates (75%) displayed multiresistance, and pulsotype analysis showed a high diversity. PMID:21976766

  13. Staphylococcus haemolyticus as an Important Hospital Pathogen and Carrier of Methicillin Resistance Genes

    PubMed Central

    Barros, E. M.; Ceotto, H.; Bastos, M. C. F.; dos Santos, K. R. N.

    2012-01-01

    Phenotypic and molecular methods were used to characterize the antibiotic resistance of 64 clinical isolates of Staphylococcus haemolyticus. By PCR of the mecA gene, 87% were found to be methicillin resistant. Approximately 55% harbored staphylococcal cassette chromosome mec element (SCCmec) type V, and only one SCCmec type IV. Many isolates (75%) displayed multiresistance, and pulsotype analysis showed a high diversity. PMID:21976766

  14. Surgical Site Infection by Methicillin Resistant Staphylococcus aureus– on Decline?

    PubMed Central

    Bhattacharya, Susmita; Jain, Sonia; Chatterjee, Shiv Sekhar; Konar, Jayashree

    2016-01-01

    Introduction Surgical Site Infection (SSI) is the most common healthcare associated infection that could be averted by antibiotics prophylaxis against the probable offending organisms. As Staphylococcus aureus has been playing a substantial role in the aetiology of SSIs, Methicillin Resistant Staphylococcus aureus (MRSA) happens to be a problem while dealing with the postoperative wound infection. Aim To determine the prevalence of SSI caused by MRSA and the antibiotic sensitivity pattern of MRSA. Materials and Methods A cross-sectional study was conducted at Nil Ratan Sircar Medical College, Kolkata, West Bengal from July 2009 to December 2012. A total of 19,359 surgical procedures were done of which 3003 culture positive SSIs have been documented. The clinical samples were collected from patients of both sexes and all ages suspected to be suffering from SSI from different specialities. Samples were processed according to CLSI, 2007 guidelines. The isolated strains of Staphylococcus aureus were screened for MRSA by detection of resistance to Cefoxitin disc (zone of inhibition was ≤21 mm) and slidex staph latex agglutination tests were done on cefoxitin resistant strains to spot phenotypic expression of mec A gene. Then PCR was performed for detection of mecA gene. Antibiotic sensitivity test was done following Kirby Bauer technique. Results In this 3½ year study, 1049 Staphylococcus aureus (34.93%) were reported from 3003 cases of SSI followed by Escherichia coli (20.34%), Klebsiella spp. (18.08%), Pseudomonas spp. (7.99%), Acinetobacter spp. (7.49%) respectively. Among the Staphylococcus aureus, 267 strains were derived as MRSA (25.45%). MRSA were isolated from 167 (62.54%) male patients and 100 (37.45%) female patients having surgical site infections. Inpatients and outpatients distribution of MRSA were 235 (88.01%) and 32 (11.98%) respectively. Majority of the MRSA cases were reported from Surgery (12.49%) and Orthopaedics (11.85%) departments in the age

  15. Resistance to fluoroquinolones and methicillin in ophthalmic isolates of Staphylococcus pseudintermedius from companion animals

    PubMed Central

    Kang, Min-Hee; Chae, Min-Joo; Yoon, Jang-Won; Lee, So-Young; Yoo, Jong-Hyun; Park, Hee-Myung

    2014-01-01

    Resistance to fluoroquinolones and methicillin was determined for 49 ophthalmic isolates of Staphylococcus pseudintermedius from dogs with and without ophthalmic disease. Resistance was observed for ciprofloxacin (40.8%), ofloxacin (38.8%), enrofloxacin (38.8%), levofloxacin (34.7%), and moxifloxacin (4.1%). Eighteen isolates, 16 of which were resistant to oxacillin, were mecA-positive. Nine of the 16 oxacillin-resistant mecA-positive S. pseudintermedius isolates were resistant to more than one fluoroquinolone and 2 isolates were resistant to 5 fluoroquinolones. The frequency of mecA gene occurrence and fluoroquinolone resistance was twice as high among S. pseudintermedius isolates derived from dogs with ophthalmic disease compared with isolates for dogs without ophthalmic disease. The high prevalence of methicillin and fluoroquinolone resistance in S. pseudintermedius from dogs with ophthalmic disease is a concern. PMID:24982521

  16. Resistance to fluoroquinolones and methicillin in ophthalmic isolates of Staphylococcus pseudintermedius from companion animals.

    PubMed

    Kang, Min-Hee; Chae, Min-Joo; Yoon, Jang-Won; Lee, So-Young; Yoo, Jong-Hyun; Park, Hee-Myung

    2014-07-01

    Resistance to fluoroquinolones and methicillin was determined for 49 ophthalmic isolates of Staphylococcus pseudintermedius from dogs with and without ophthalmic disease. Resistance was observed for ciprofloxacin (40.8%), ofloxacin (38.8%), enrofloxacin (38.8%), levofloxacin (34.7%), and moxifloxacin (4.1%). Eighteen isolates, 16 of which were resistant to oxacillin, were mecA-positive. Nine of the 16 oxacillin-resistant mecA-positive S. pseudintermedius isolates were resistant to more than one fluoroquinolone and 2 isolates were resistant to 5 fluoroquinolones. The frequency of mecA gene occurrence and fluoroquinolone resistance was twice as high among S. pseudintermedius isolates derived from dogs with ophthalmic disease compared with isolates for dogs without ophthalmic disease. The high prevalence of methicillin and fluoroquinolone resistance in S. pseudintermedius from dogs with ophthalmic disease is a concern. PMID:24982521

  17. Classification and characteristics of coagulase-negative, methicillin-resistant staphylococci.

    PubMed

    Wilkinson, B J; Maxwell, S; Schaus, S M

    1980-08-01

    Sixty-five clinical isolates of coagulase-negative, methicillin-resistant staphylococci have been classified as Staphylococcus epidermidis (63.0%), "phosphatase-negative S. epidermidis" (12.3%), coagulase-negative Staphylococcus aureus (6.2%), Staphylococcus hemolyticus (6.2%), Staphylococcus hominis (3.1%), and Staphylococcus warneri (1.5%). Five of the organisms (7.7%) could not be classified with certainty as currently recognized species. Novobiocin resistance was encountered in eight of the strains, but these were not classified as the accepted novobiocin-resistant staphylococcal species. Some differences in antibiotic resistance patterns to those typical of methicillin-resistant S. aureus were noted in that, although 29 strains were resistant to methicillin, penicillin, sulfamethizole, streptomycin, and tetracycline, the remainder of the strains were sensitive to streptomycin or tetracycline or both. In a majority of the strains (42 of 65), methicillin susceptibility testing by the disk method at 30 or at 37 degrees C in the presence of NaCl did not appear to enhance resistance expression. Most of the strains produced beta-lactamase (EC 3.5.2.6), but none of the 21 strains tested produced enterotoxin B.

  18. Classification and characteristics of coagulase-negative, methicillin-resistant staphylococci.

    PubMed

    Wilkinson, B J; Maxwell, S; Schaus, S M

    1980-08-01

    Sixty-five clinical isolates of coagulase-negative, methicillin-resistant staphylococci have been classified as Staphylococcus epidermidis (63.0%), "phosphatase-negative S. epidermidis" (12.3%), coagulase-negative Staphylococcus aureus (6.2%), Staphylococcus hemolyticus (6.2%), Staphylococcus hominis (3.1%), and Staphylococcus warneri (1.5%). Five of the organisms (7.7%) could not be classified with certainty as currently recognized species. Novobiocin resistance was encountered in eight of the strains, but these were not classified as the accepted novobiocin-resistant staphylococcal species. Some differences in antibiotic resistance patterns to those typical of methicillin-resistant S. aureus were noted in that, although 29 strains were resistant to methicillin, penicillin, sulfamethizole, streptomycin, and tetracycline, the remainder of the strains were sensitive to streptomycin or tetracycline or both. In a majority of the strains (42 of 65), methicillin susceptibility testing by the disk method at 30 or at 37 degrees C in the presence of NaCl did not appear to enhance resistance expression. Most of the strains produced beta-lactamase (EC 3.5.2.6), but none of the 21 strains tested produced enterotoxin B. PMID:6971871

  19. Distribution of mec regulator genes in methicillin-resistant Staphylococcus clinical strains.

    PubMed Central

    Suzuki, E; Kuwahara-Arai, K; Richardson, J F; Hiramatsu, K

    1993-01-01

    The distributions of the mec regulator genes mecI and mecR1, which were identified on the chromosome of mecA-carrying Staphylococcus aureus N315, in methicillin-resistant staphylococci isolated in Japan and various countries were studied. Screening by dot blot hybridization by using polymerase chain reaction (PCR)-amplified probes revealed that at least the 5'-end region of the mecR1 gene was present in all strains tested, whereas about 40% of the strains were negative for the mecI gene. The data suggested that these regulator genes were the original components of the additional mec region DNA of methicillin-resistant S. aureus as well as methicillin-resistant, coagulase-negative staphylococci of seven staphylococcal species (S. epidermidis, S. haemolyticus, S. hominis, S. sciuri, S. capitis, S. caprae, and S. warneri). The mecI gene, which presumably codes for the repressor protein of the mecA gene, was found to harbor a point mutation in all six mecI-positive methicillin-resistant S. aureus strains, and their basal level of mecA gene transcription was elevated compared with that of strain N315, which harbors a presumably intact counterpart of the mecI gene. The data suggested that the mecI gene encodes for a strong repressor function on mecA gene transcription and is deleted or mutated in clinical methicillin-resistant S. aureus strains with high levels of resistance to methicillin. Images PMID:8328773

  20. Bovine mastitis Staphylococcus aureus: antibiotic susceptibility profile, resistance genes and molecular typing of methicillin-resistant and methicillin-sensitive strains in China.

    PubMed

    Wang, Dengfeng; Wang, Zhicai; Yan, Zuoting; Wu, Jianyong; Ali, Tariq; Li, Jianjun; Lv, Yanli; Han, Bo

    2015-04-01

    The emergence of methicillin-resistant Staphylococcus aureus (MRSA) infection in dairy animals is of great concern for livestock and public health. The aim of present study was to detect new trends of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) towards antibiotic susceptibility, resistance genes and molecular typing by methods of disc diffusion, multiplex PCR assay and multilocus sequence typing (MLST). A total of 219 S. aureus strains were isolated from bovine mastitis cases from six provinces of China, including 34 MRSA strains. The results revealed that more than 70% isolated strains showed resistance to various antibiotics, and multiple-drugs resistance to more than five categories of antibiotics was found more common. The ermC was the most prevalent resistance gene, followed by other genes; however, ermA was the least frequently detected gene. Twenty-eight mecA-negative MRSA and six mecA-positive MRSA strains were detected, and in which three strains were ST97-MRSA-IV, others were ST965-MRSA-IV, ST6-MRSA-IV and ST9-MRSA-SCCmec-NT. The mecA-negative MRSA strains were found resistant to most of the antibiotics, and harbored aac(6')/aph(2''), aph(3')-III and tetM genes higher than MSSA strains. The resistance to most of the antibiotics was significantly higher in MRSA than in MSSA strains. The MLST profiles showed that these strains mainly belonged to CC5, CC398, CC121 and CC50 lineage, especially within ST97 and ST398, while some novel sequence types (ST2154, ST2165 and ST2166) were identified and deposited in the MLST database. This indicates that the resistance of S. aureus is becoming more complicated by changes in multi-drug resistance mechanism and appearance of mecA-negative MRSA isolates, and importantly, MRSA-IV strains in different MLST types are emerging.

  1. Desired vancomycin trough serum concentration for treating invasive methicillin-resistant Staphylococcal infections.

    PubMed

    Frymoyer, Adam; Guglielmo, B Joseph; Hersh, Adam L

    2013-10-01

    Vancomycin area under the curve/minimal inhibitory concentration (AUC/MIC) >400 best predicts the outcome when treating invasive methicillin-resistant Staphylococcus aureus infection; however, trough serum concentrations are used clinically to assess the appropriateness of dosing. We used pharmacokinetic modeling and simulation to examine the relationship between vancomycin trough values and AUC/MIC in children receiving vancomycin 15 mg/kg every 6 hours and methicillin-resistant Staphylococcus aureus MIC of 1 μg/mL. A trough of 7-10 μg/mL predicted achievement of AUC/MIC >400 in >90% of children.

  2. Targeting methicillin-resistant Staphylococcus aureus with short salt-resistant synthetic peptides.

    PubMed

    Mohamed, Mohamed F; Hamed, Maha I; Panitch, Alyssa; Seleem, Mohamed N

    2014-07-01

    The seriousness of microbial resistance combined with the lack of new antimicrobials has increased interest in the development of antimicrobial peptides (AMPs) as novel therapeutics. In this study, we evaluated the antimicrobial activities of two short synthetic peptides, namely, RRIKA and RR. These peptides exhibited potent antimicrobial activity against Staphylococcus aureus, and their antimicrobial effects were significantly enhanced by addition of three amino acids in the C terminus, which consequently increased the amphipathicity, hydrophobicity, and net charge. Moreover, RRIKA and RR demonstrated a significant and rapid bactericidal effect against clinical and drug-resistant Staphylococcus isolates, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate S. aureus (VISA), vancomycin-resistant S. aureus (VRSA), linezolid-resistant S. aureus, and methicillin-resistant Staphylococcus epidermidis. In contrast to many natural AMPs, RRIKA and RR retained their activity in the presence of physiological concentrations of NaCl and MgCl2. Both RRIKA and RR enhanced the killing of lysostaphin more than 1,000-fold and eradicated MRSA and VRSA isolates within 20 min. Furthermore, the peptides presented were superior in reducing adherent biofilms of S. aureus and S. epidermidis compared to results with conventional antibiotics. Our findings indicate that the staphylocidal effects of our peptides were through permeabilization of the bacterial membrane, leading to leakage of cytoplasmic contents and cell death. Furthermore, peptides were not toxic to HeLa cells at 4- to 8-fold their antimicrobial concentrations. The potent and salt-insensitive antimicrobial activities of these peptides present an attractive therapeutic candidate for treatment of multidrug-resistant S. aureus infections.

  3. Targeting methicillin-resistant Staphylococcus aureus with short salt-resistant synthetic peptides.

    PubMed

    Mohamed, Mohamed F; Hamed, Maha I; Panitch, Alyssa; Seleem, Mohamed N

    2014-07-01

    The seriousness of microbial resistance combined with the lack of new antimicrobials has increased interest in the development of antimicrobial peptides (AMPs) as novel therapeutics. In this study, we evaluated the antimicrobial activities of two short synthetic peptides, namely, RRIKA and RR. These peptides exhibited potent antimicrobial activity against Staphylococcus aureus, and their antimicrobial effects were significantly enhanced by addition of three amino acids in the C terminus, which consequently increased the amphipathicity, hydrophobicity, and net charge. Moreover, RRIKA and RR demonstrated a significant and rapid bactericidal effect against clinical and drug-resistant Staphylococcus isolates, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate S. aureus (VISA), vancomycin-resistant S. aureus (VRSA), linezolid-resistant S. aureus, and methicillin-resistant Staphylococcus epidermidis. In contrast to many natural AMPs, RRIKA and RR retained their activity in the presence of physiological concentrations of NaCl and MgCl2. Both RRIKA and RR enhanced the killing of lysostaphin more than 1,000-fold and eradicated MRSA and VRSA isolates within 20 min. Furthermore, the peptides presented were superior in reducing adherent biofilms of S. aureus and S. epidermidis compared to results with conventional antibiotics. Our findings indicate that the staphylocidal effects of our peptides were through permeabilization of the bacterial membrane, leading to leakage of cytoplasmic contents and cell death. Furthermore, peptides were not toxic to HeLa cells at 4- to 8-fold their antimicrobial concentrations. The potent and salt-insensitive antimicrobial activities of these peptides present an attractive therapeutic candidate for treatment of multidrug-resistant S. aureus infections. PMID:24798285

  4. Characterization of methicillin-resistant Staphylococcus spp. isolated from dogs in Korea.

    PubMed

    Jang, Yunho; Bae, Dong hwa; Cho, Jae-Keun; Bahk, Gyung Jin; Lim, Suk-Kyung; Lee, Young Ju

    2014-11-01

    Staphylococci were isolated from dogs in animal hospitals, animal shelters, and the Daegu PET EXPO to investigate the characteristics of circulating methicillin-resistant Staphylococcal (MRS) strains in companion animals in Korea. A total of 36/157 isolates were classified as MRS, and subdivided as follows: 1 methicillin-resistant Staphylococcus aureus (MRSA), 4 methicillin-resistant Staphylococcus epidermidis, 2 methicillin-resistant Staphylococcus haemolyticus, and 29 MRS spp. Among the 36 MRS isolates tested, 100% were resistant to oxacillin and penicillin, and at least 50% were resistant to sulfamethoxazole/trimethoprim (69.4%), erythromycin (63.9%), tetracycline (58.3%), cefoxitin (55.6%), clindamycin (50.0%) or pirlimycin (50.0%). Additionally, 34/36 MRS isolates (94.4%) were mecA positive, 15 of which were further classified as SCCmec type V, 6 isolates as type I, 4 isolates as type IIIb, 1 isolate as type IVa, 1 isolate as type IV, with 7 isolates being non-classifiable. The results of multilocus sequence typing and spa typing for the one MRSA strain were ST 72 (1-4-1-8-4-4-3) and spa t148. Our results provide evidence that companion animals like dogs may be MRS carriers, and that continued surveillance of MRS in companion animals is required to prevent increased incidences in humans.

  5. Characterization of methicillin-resistant Staphylococcus spp. isolated from dogs in Korea.

    PubMed

    Jang, Yunho; Bae, Dong hwa; Cho, Jae-Keun; Bahk, Gyung Jin; Lim, Suk-Kyung; Lee, Young Ju

    2014-11-01

    Staphylococci were isolated from dogs in animal hospitals, animal shelters, and the Daegu PET EXPO to investigate the characteristics of circulating methicillin-resistant Staphylococcal (MRS) strains in companion animals in Korea. A total of 36/157 isolates were classified as MRS, and subdivided as follows: 1 methicillin-resistant Staphylococcus aureus (MRSA), 4 methicillin-resistant Staphylococcus epidermidis, 2 methicillin-resistant Staphylococcus haemolyticus, and 29 MRS spp. Among the 36 MRS isolates tested, 100% were resistant to oxacillin and penicillin, and at least 50% were resistant to sulfamethoxazole/trimethoprim (69.4%), erythromycin (63.9%), tetracycline (58.3%), cefoxitin (55.6%), clindamycin (50.0%) or pirlimycin (50.0%). Additionally, 34/36 MRS isolates (94.4%) were mecA positive, 15 of which were further classified as SCCmec type V, 6 isolates as type I, 4 isolates as type IIIb, 1 isolate as type IVa, 1 isolate as type IV, with 7 isolates being non-classifiable. The results of multilocus sequence typing and spa typing for the one MRSA strain were ST 72 (1-4-1-8-4-4-3) and spa t148. Our results provide evidence that companion animals like dogs may be MRS carriers, and that continued surveillance of MRS in companion animals is required to prevent increased incidences in humans. PMID:25597186

  6. Methicillin-resistant Staphylococcus aureus (MRSA) among dental patients: a problem for infection control in dentistry?

    PubMed

    Zimmerli, Melanie; Widmer, Andreas F; Dangel, Marc; Filippi, Andreas; Frei, Reno; Meyer, Jürg

    2009-12-01

    We assessed the frequency of carriers of methicillin-resistant Staphylococcus aureus (MRSA) among 500 dental patients of a university clinic. From each participant, two specimens were taken from the anterior nares and the pharynx and analysed by culture. The participants completed a questionnaire on possible risk factors of MRSA infection. Two hundred ten individuals carried S. aureus, 90 in the nares only, 51 in the throat only and 69 in nares and throat. Isolates of 208 patients were methicillin-sensitive; two isolates were methicillin-resistant, both carried in the throat exclusively. In conclusion, the frequency of nasal and/or throat carriers of MRSA among dental patients was low and suggests few opportunities of exposure in the dental clinic assessed.

  7. Molecular Characteristics of Methicillin-Resistant Staphylococcus epidermidis on the Abdominal Skin of Females before Laparotomy

    PubMed Central

    Wang, Pin-Jia; Xie, Cheng-Bin; Sun, Feng-Hui; Guo, Li-Juan; Dai, Min; Cheng, Xi; Ma, Yong-Xin

    2016-01-01

    Staphylococcus epidermidis, especially methicillin-resistant strains, may be the source of surgical site infections and may be a reservoir of staphylococcal cassette chromosome mec (SCCmec) for S. aureus. The aim of this study was to investigate the prevalence of methicillin-resistant S. epidermidis (MRSE) on the abdominal skin of females before laparotomy and determine the molecular characteristics and antimicrobial susceptibility patterns of these isolates. MRSE was found in 54 of 157 isolates based on mecA gene detection, and there was no difference in icaA gene carriage rate between MRSE and methicillin-susceptible S. epidermidis (MSSE) isolates. Antimicrobial susceptibility profiles were determined by broth microdilution antimicrobial susceptibility testing according to the latest CLSI manuals. All MRSE isolates had unfavorable antimicrobial susceptibility patterns. Twenty-three MRSE strains (42.6%) were multi-drug resistant. SCCmec typing and pulsed field gel electrophoresis (PFGE) typing was performed. Thirty-nine (72.2%) had a single SCCmec type, whereas 1.9% had two types. Fourteen strains (25.9%) were non-typeable (NT). The most frequent MRSE genotype was SCCmec type IVa. High diversity with PFGE patterns was obtained for MRSE, and there were no isolates exhibiting identical pulsotype. The results confirm that methicillin-resistant strains are frequently present among S. epidermidis on the abdominal skin of females before laparotomy. Moreover, resistance profiles seem to have no association with the SCCmec types or PFGE types for most common antibiotics. PMID:27338374

  8. Molecular Characteristics of Methicillin-Resistant Staphylococcus epidermidis on the Abdominal Skin of Females before Laparotomy.

    PubMed

    Wang, Pin-Jia; Xie, Cheng-Bin; Sun, Feng-Hui; Guo, Li-Juan; Dai, Min; Cheng, Xi; Ma, Yong-Xin

    2016-06-22

    Staphylococcus epidermidis, especially methicillin-resistant strains, may be the source of surgical site infections and may be a reservoir of staphylococcal cassette chromosome mec (SCCmec) for S. aureus. The aim of this study was to investigate the prevalence of methicillin-resistant S. epidermidis (MRSE) on the abdominal skin of females before laparotomy and determine the molecular characteristics and antimicrobial susceptibility patterns of these isolates. MRSE was found in 54 of 157 isolates based on mecA gene detection, and there was no difference in icaA gene carriage rate between MRSE and methicillin-susceptible S. epidermidis (MSSE) isolates. Antimicrobial susceptibility profiles were determined by broth microdilution antimicrobial susceptibility testing according to the latest CLSI manuals. All MRSE isolates had unfavorable antimicrobial susceptibility patterns. Twenty-three MRSE strains (42.6%) were multi-drug resistant. SCCmec typing and pulsed field gel electrophoresis (PFGE) typing was performed. Thirty-nine (72.2%) had a single SCCmec type, whereas 1.9% had two types. Fourteen strains (25.9%) were non-typeable (NT). The most frequent MRSE genotype was SCCmec type IVa. High diversity with PFGE patterns was obtained for MRSE, and there were no isolates exhibiting identical pulsotype. The results confirm that methicillin-resistant strains are frequently present among S. epidermidis on the abdominal skin of females before laparotomy. Moreover, resistance profiles seem to have no association with the SCCmec types or PFGE types for most common antibiotics.

  9. Molecular Characteristics of Methicillin-Resistant Staphylococcus epidermidis on the Abdominal Skin of Females before Laparotomy.

    PubMed

    Wang, Pin-Jia; Xie, Cheng-Bin; Sun, Feng-Hui; Guo, Li-Juan; Dai, Min; Cheng, Xi; Ma, Yong-Xin

    2016-01-01

    Staphylococcus epidermidis, especially methicillin-resistant strains, may be the source of surgical site infections and may be a reservoir of staphylococcal cassette chromosome mec (SCCmec) for S. aureus. The aim of this study was to investigate the prevalence of methicillin-resistant S. epidermidis (MRSE) on the abdominal skin of females before laparotomy and determine the molecular characteristics and antimicrobial susceptibility patterns of these isolates. MRSE was found in 54 of 157 isolates based on mecA gene detection, and there was no difference in icaA gene carriage rate between MRSE and methicillin-susceptible S. epidermidis (MSSE) isolates. Antimicrobial susceptibility profiles were determined by broth microdilution antimicrobial susceptibility testing according to the latest CLSI manuals. All MRSE isolates had unfavorable antimicrobial susceptibility patterns. Twenty-three MRSE strains (42.6%) were multi-drug resistant. SCCmec typing and pulsed field gel electrophoresis (PFGE) typing was performed. Thirty-nine (72.2%) had a single SCCmec type, whereas 1.9% had two types. Fourteen strains (25.9%) were non-typeable (NT). The most frequent MRSE genotype was SCCmec type IVa. High diversity with PFGE patterns was obtained for MRSE, and there were no isolates exhibiting identical pulsotype. The results confirm that methicillin-resistant strains are frequently present among S. epidermidis on the abdominal skin of females before laparotomy. Moreover, resistance profiles seem to have no association with the SCCmec types or PFGE types for most common antibiotics. PMID:27338374

  10. Resistance of canine methicillin-resistant Staphylococcus pseudintermedius strains to pradofloxacin.

    PubMed

    Kizerwetter-Świda, Magdalena; Chrobak-Chmiel, Dorota; Rzewuska, Magdalena; Binek, Marian

    2016-09-01

    We investigated in vitro activity of a novel veterinary fluoroquinolone, pradofloxacin, against methicillin-resistant Staphylococcus pseudintermedius (MRSP) isolates and compared with other fluoroquinolones. A total of 38 MRSP isolates were subjected to agar disk diffusion tests for sensitivity to pradofloxacin, orbifloxacin, marbofloxacin, enrofloxacin, and ciprofloxacin. The minimal inhibitory concentration (MIC) values of pradofloxacin, ciprofloxacin, and enrofloxacin were determined. Mutations in the genes encoding DNA gyrase subunit A (GyrA) and topoisomerase IV (GrlA) proteins associated with fluoroquinolone resistance were studied by an analysis of partial sequences of the genes encoding these proteins. Two MRSP isolates were susceptible in disk diffusion and microdilution test to all fluoroquinolones tested, including pradofloxacin. Based on the results of the disk diffusion testing, 33 of 38 isolates showed resistance to pradofloxacin and 3 were intermediate, whereas, by pradofloxacin MIC testing, 35 isolates were classified as resistant and 1 as intermediate. Single alterations in GyrA and GrlA proteins were observed in the 35 resistant isolates and the 1 intermediate isolate (MIC results). These same 36 isolates were also resistant to the other tested fluoroquinolones. The results of the current study showed that MRSP isolates are usually resistant to all fluoroquinolones, including pradofloxacin. Therefore, in routine susceptibility testing to pradofloxacin by disk diffusion, the results should be carefully interpreted for MRSP isolates, especially those resistant to other fluoroquinolones and, in questionable cases, the pradofloxacin MIC should be determined to confirm the susceptibility testing results.

  11. Quantitative differences in antibiotic resistance between methicillin-resistant and methicillin-susceptible Staphylococcus aureus strains isolated in Hungary, Austria and Macedonia.

    PubMed

    Horvath, A; Rozgonyi, F; Pesti, N; Kocsis, E; Malmos, G; Kristof, K; Nagy, K; Lagler, H; Presterl, E; Stich, K; Gattringer, R; Kotolacsi, G; Cekovska, Z; Graninger, W

    2010-08-01

    The aim of this study was to compare the quantitative susceptibility of methicillin-resistant and -susceptible Staphylococcus aureus (MRSA and MSSA) strains from three European countries to nine antistaphylococcal agents. The antibiotic susceptibility of 274 MRSA and 284 MSSA strains from Hungary, Austria and macedonia was tested by the broth microdilution method. The clonal relationship of strains was determined by pulsed-field gel electrophoresis. Intermediate susceptibility to vancomycin appeared in Macedonian MRSA strains. Macedonian MRSA strains had high-level amikacin and gentamicin resistance. MSSA strains generally were susceptible to all drugs at minimum inhibitory concentrations (MIC(50)) except for gentamicin resistance in Macedonian strains. In Hungary and Austria a common antibiotic resistance phenotype of MRSA predominated, while in macedonia three other phenotypes were also prevalent. Geographical differences in the resistance of S. aureus are still high. Since resistance levels of MRSA and MSSA strains differ extensively, they should be considered separately for antibiotic resistance analysis.

  12. Quantitative NMR metabolite profiling of methicillin-resistant and methicillin-susceptible Staphylococcus aureus discriminates between biofilm and planktonic phenotypes.

    PubMed

    Ammons, Mary Cloud B; Tripet, Brian P; Carlson, Ross P; Kirker, Kelly R; Gross, Michael A; Stanisich, Jessica J; Copié, Valérie

    2014-06-01

    Wound bioburden in the form of colonizing biofilms is a major contributor to nonhealing wounds. Staphylococcus aureus is a Gram-positive, facultative anaerobe commonly found in chronic wounds; however, much remains unknown about the basic physiology of this opportunistic pathogen, especially with regard to the biofilm phenotype. Transcriptomic and proteomic analysis of S. aureus biofilms have suggested that S. aureus biofilms exhibit an altered metabolic state relative to the planktonic phenotype. Herein, comparisons of extracellular and intracellular metabolite profiles detected by (1)H NMR were conducted for methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) S. aureus strains grown as biofilm and planktonic cultures. Principal component analysis distinguished the biofilm phenotype from the planktonic phenotype, and factor loadings analysis identified metabolites that contributed to the statistical separation of the biofilm from the planktonic phenotype, suggesting that key features distinguishing biofilm from planktonic growth include selective amino acid uptake, lipid catabolism, butanediol fermentation, and a shift in metabolism from energy production to assembly of cell-wall components and matrix deposition. These metabolite profiles provide a basis for the development of metabolite biomarkers that distinguish between biofilm and planktonic phenotypes in S. aureus and have the potential for improved diagnostic and therapeutic use in chronic wounds.

  13. Methicillin-resistant coagulase-negative staphylococci from healthy dogs in Nsukka, Nigeria.

    PubMed

    Chah, Kennedy F; Gómez-Sanz, Elena; Nwanta, John A; Asadu, Brendan; Agbo, Ifeoma C; Lozano, Carmen; Zarazaga, Myriam; Torres, Carmen

    2014-01-01

    The occurrence, resistance phenotype and molecular mechanisms of resistance of methicillin-resistant staphylococci from groin swabs of 109 clinically healthy dogs in Nsukka, Nigeria were investigated. The groin swab samples were cultured on mannitol salt agar supplemented with 10 μg of cloxacillin. Sixteen methicillin-resistant coagulase negative staphylococci (MRCoNS), all harbouring the mecA gene were isolated from 14 (12.8%) of the 109 dogs studied. The MRCoNS isolated were: S. sciuri subspecies rodentium, S. lentus, S. haemolyticus, and S. simulans with S. sciuri subspecies rodentium (62.5%) being the predominant species. Thirteen (81.3%) of the MRCoNS were resistant to tetracycline while 12 (75%) and 10 (62.5%) were resistant to kanamycin and trimthoprim-sulphamethoxazole respectively. None of the isolates was resistant to fusidic acid, linezolid and vancomycin. Thirteen (81.3%) of the MRCoNS were multi-drug resistance (MDR). Other antimicrobial genes detected were: blaZ, tet(K), tet(M), tet(L), erm(B), lnu(A), aacA-aphD, aphA3, str, dfr(G), cat pC221 , and cat pC223 . Methicillin-resistant staphylococci are common colonizers of healthy dogs in Nigeria with a major species detected being S. sciuri subsp. rodentium. PMID:24948934

  14. Epidemiology and genotypic characteristics of Methicillin-Resistant Staphylococcus aureus strains of porcine origin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The main goal of this study was to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA), particularly livestock-associated (LA)-MRSA in pigs and pork. Genotypic relatedness of isolates on-farm, at slaughter and retail was assessed. Paired nasal and peri-anal swab samples we...

  15. A case of methicillin-resistant Staphylococcus pseudintermedius (MRSP) pyoderma in a Labrador retriever dog.

    PubMed

    Wan, Jennifer

    2014-11-01

    An 8-year-old, neutered male Labrador retriever dog with generalized pruritis had a history of recurring atopic dermatitis and superficial pyoderma. Cocci and yeast were found on cytology and methicillin-resistant Staphylococcus pseudintermedius was cultured. A regimen of marbofloxacin, dexamethasone, ketoconazole, and cyclosporine in addition to bathing with 2% chlorhexidine shampoo resulted in marked improvement.

  16. Cluster of Infections Caused by Methicillin-Resistant Staphylococcus pseudintermedius in Humans in a Tertiary Hospital

    PubMed Central

    Börjesson, Stefan; Grönlund-Andersson, Ulrika; Tellgren-Roth, Christian; Melhus, Åsa

    2014-01-01

    The dog-associated Staphylococcus pseudintermedius is a rare pathogen in humans. Here we describe a cluster of infections caused by the methicillin-resistant S. pseudintermedius clone ST71-J-t02-II–III. It involved four elderly patients at a tertiary hospital. Three patients had wound infections, and the strain had a tendency to cause bullous skin lesions. PMID:24871217

  17. Presence of Methicillin-Resistant Staphylococcus aureus in Pigs in Peru

    PubMed Central

    Arriola, Carmen S.; Güere, Mariella E.; Larsen, Jesper; Skov, Robert L.; Gilman, Robert H.; Gonzalez, Armando E.; Silbergeld, Ellen K.

    2011-01-01

    We report the first detection of methicillin-resistant Staphylococcus aureus isolates in pigs in Peru. The isolates belong to a livestock-associated lineage previously reported in North America and Europe, CC398, and a highly virulent USA300-like ST8-IV variant, which is the predominant community-associated lineage in Latin America. PMID:22174831

  18. A case of methicillin-resistant Staphylococcus pseudintermedius (MRSP) pyoderma in a Labrador retriever dog.

    PubMed

    Wan, Jennifer

    2014-11-01

    An 8-year-old, neutered male Labrador retriever dog with generalized pruritis had a history of recurring atopic dermatitis and superficial pyoderma. Cocci and yeast were found on cytology and methicillin-resistant Staphylococcus pseudintermedius was cultured. A regimen of marbofloxacin, dexamethasone, ketoconazole, and cyclosporine in addition to bathing with 2% chlorhexidine shampoo resulted in marked improvement. PMID:25392557

  19. Preventing Community-Associated Methicillin-Resistant "Staphylococcus aureus" among Student Athletes

    ERIC Educational Resources Information Center

    Many, Patricia S.

    2008-01-01

    Methicillin-resistant "Staphylococcus aureus" (MRSA) was once thought to be a bacterium causing infections in only hospitalized patients. However, a new strain of MRSA has emerged among healthy individuals who have not had any recent exposure to a hospital or to medical procedures. This new strain is known as "community-associated MRSA". Studies…

  20. Community-associated methicillin resistant Staphylococcus aureus in south Florida hospital and recreational environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Strains of methicillin resistant Staphylococcus aureus (MRSA), a frequent human pathogen, may also be found in the flora of healthy persons and in the environments that they frequent. Strains of MRSA circulating in the community classified as USA 300 are now found not only in the community but also...

  1. Evidence for Human Adaptation and Foodborne Transmission of Livestock-Associated Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Larsen, Jesper; Stegger, Marc; Andersen, Paal S.; Petersen, Andreas; Larsen, Anders R.; Westh, Henrik; Agersø, Yvonne; Fetsch, Alexandra; Kraushaar, Britta; Käsbohrer, Annemarie; Feβler, Andrea T.; Schwarz, Stefan; Cuny, Christiane; Witte, Wolfgang; Butaye, Patrick; Denis, Olivier; Haenni, Marisa; Madec, Jean-Yves; Jouy, Eric; Laurent, Frederic; Battisti, Antonio; Franco, Alessia; Alba, Patricia; Mammina, Caterina; Pantosti, Annalisa; Monaco, Monica; Wagenaar, Jaap A.; de Boer, Enne; van Duijkeren, Engeline; Heck, Max; Domínguez, Lucas; Torres, Carmen; Zarazaga, Myriam; Price, Lance B.; Skov, Robert L.

    2016-01-01

    We investigated the evolution and epidemiology of a novel livestock-associated methicillin-resistant Staphylococcus aureus strain, which colonizes and infects urban-dwelling Danes even without a Danish animal reservoir. Genetic evidence suggests both poultry and human adaptation, with poultry meat implicated as a probable source. PMID:27655995

  2. Draft Genome Sequences of Two Methicillin-Resistant Clinical Staphylococcus aureus Isolates

    PubMed Central

    Sung, Kidon; Iram, Saira; Nawaz, Mohamed; Xu, Joshua

    2016-01-01

    Here, we report the draft genome sequences of two methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates, hospital-associated perirectal isolate 32S (ST 239) from a colitis tracheostomy patient and community-associated MRSA isolate 42S (ST 772) from a hepatic-splenomegaly patient in Rawalpindi, Pakistan. PMID:26868381

  3. Carriage of methicillin-resistant Staphylococcus aureus by healthy companion animals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methicillin-resistant Staphylococcus aureus (MRSA) is a significant human pathogen and has also been associated with wounded or ill companion animals. Healthy animals may also harbor MRSA without presenting any symptoms, but little is known about the prevalence of MRSA among these animals. Therefo...

  4. Methicillin-Resistant Staphylococcus aureus Prevalence among Captive Chimpanzees, Texas, USA, 20121

    PubMed Central

    Barnhart, Kirstin F.; Abee, Christian R.; Lambeth, Susan P.; Weese, J. Scott

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infection in humans and animals is concerning. In 2012, our evaluation of a captive chimpanzee colony in Texas revealed MRSA prevalence of 69%. Animal care staff should be aware of possible zoonotic MRSA transmission resulting from high prevalence among captive chimpanzees. PMID:26583847

  5. Scarlet fever caused by community-associated methicillin-resistant Staphylococcus aureus.

    PubMed

    Lu, Ying-Chun; Chen, Shyi-Jou; Lo, Wen-Tsung

    2011-07-01

    We describe a previously healthy 2.5-year-old boy with staphylococcal scarlet fever associated with acute suppurative otitis media due to community-associated methicillin-resistant Staphylococcus aureus. The patient was successfully treated by spontaneous drainage in combination with trimethoprim-sulfamethoxazole therapy.

  6. First report of infection with community-acquired methicillin-resistant Staphylococcus aureus in South America.

    PubMed

    Ribeiro, Apoena; Dias, Cícero; Silva-Carvalho, Maria Cícera; Berquó, Laura; Ferreira, Fabienne Antunes; Santos, Raquel Neves Soares; Ferreira-Carvalho, Bernadete Teixeira; Figueiredo, Agnes Marie

    2005-04-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has recently emerged in the southwestern Pacific, North America, and Europe. These S. aureus isolates frequently shared some genetic characteristics, including the SCCmec type IV and lukS-lukF genes. In this paper we show that typical CA-MRSA isolates have spread to South America (Brazil).

  7. Methicillin-Resistant Staphylococcus aureus Prevalence among Captive Chimpanzees, Texas, USA, 2012(1).

    PubMed

    Hanley, Patrick W; Barnhart, Kirstin F; Abee, Christian R; Lambeth, Susan P; Weese, J Scott

    2015-12-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infection in humans and animals is concerning. In 2012, our evaluation of a captive chimpanzee colony in Texas revealed MRSA prevalence of 69%. Animal care staff should be aware of possible zoonotic MRSA transmission resulting from high prevalence among captive chimpanzees.

  8. A case of methicillin-resistant Staphylococcus pseudintermedius (MRSP) pyoderma in a Labrador retriever dog

    PubMed Central

    Wan, Jennifer

    2014-01-01

    An 8-year-old, neutered male Labrador retriever dog with generalized pruritis had a history of recurring atopic dermatitis and superficial pyoderma. Cocci and yeast were found on cytology and methicillin-resistant Staphylococcus pseudintermedius was cultured. A regimen of marbofloxacin, dexamethasone, ketoconazole, and cyclosporine in addition to bathing with 2% chlorhexidine shampoo resulted in marked improvement. PMID:25392557

  9. Congenital Cataract, Nasolacrimal Duct Obstruction, and Methicillin-Resistant Staphylococcus aureus Conjunctivitis: When to Operate?

    PubMed

    Siddiqui, Sorath Noorani; Zafar, Saemah Nuzhat

    2016-01-01

    Methicillin-resistant Staphylococcus aureus is one of the toughest organisms to treat, especially in cases where intraocular surgery is contemplated, because the risks are aggravated. Conjunctival swab culture and sensitivity tests are significant when there is history of recent hospitalization. In this report, an infant with successful cataract surgery after elimination of the organism is presented. PMID:27383382

  10. The prevalence of methicillin resistant organisms among pacemaker and defibrillator implant recipients

    PubMed Central

    Rodriguez, David J; Afzal, Aisha; Evonich, Rudolph; Haines, David E

    2012-01-01

    Introduction Pacemaker and defibrillator infections are an uncommon, but catastrophic complication of device implantation. The present study examined the prevalence of device-related infections, the patterns of antibiotic resistance, and the presence of methicillin resistant staphylococcus aureus (MRSA) nares colonization in device implant recipients. Methods Two protocols were employed using a retrospective and a prospective analysis. A retrospective chart review of 218 patients with suspected device infection from 1/2000 to 1/2011 was performed. Demographics, infection rates, and patterns of antibiotic resistance were compared. The prospective analysis enrolled one hundred eighty two patients undergoing device implantations or generator replacements. The nares were swabbed and analyzed for the presence of staphylococcus aureus, and tested for methicillin sensitivity. Results Over a period of ten years, 12,771 device implants/generator changes/system revisions were performed, with an infection rate of 1.2%. Methicillin resistance (MR) was identified in 98/218 (44.9%) of patients. Those with MR infection had more diabetes and cardiomyopathy. There was no significant increase in methicillin resistance over time (p=0.30). Our prospective analysis included 110 men. A total of 32 patients (17.6%) had positive cultures for SA: 6.6% with MRSA. Patients positive for MRSA nares colonization had a statistically significant greater length of hospital stay 8.5 days (mean) versus 4.4 days (P=0.049). Conclusions Methicillin resistant organisms appear to be emerging and persistent pathogens in device implants. The screening of MRSA colonization may identify new populations at risk. Further studies and analysis are needed to determine the cost effectiveness of a screening protocol. PMID:22720201

  11. Mutation in the C-Di-AMP Cyclase dacA Affects Fitness and Resistance of Methicillin Resistant Staphylococcus aureus

    PubMed Central

    Dengler, Vanina; McCallum, Nadine; Kiefer, Patrick; Christen, Philipp; Patrignani, Andrea; Vorholt, Julia A.; Berger-Bächi, Brigitte; Senn, Maria M.

    2013-01-01

    Faster growing and more virulent strains of methicillin resistant Staphylococcus aureus (MRSA) are increasingly displacing highly resistant MRSA. Elevated fitness in these MRSA is often accompanied by decreased and heterogeneous levels of methicillin resistance; however, the mechanisms for this phenomenon are not yet fully understood. Whole genome sequencing was used to investigate the genetic basis of this apparent correlation, in an isogenic MRSA strain pair that differed in methicillin resistance levels and fitness, with respect to growth rate. Sequencing revealed only one single nucleotide polymorphism (SNP) in the diadenylate cyclase gene dacA in the faster growing but less resistant strain. Diadenylate cyclases were recently discovered to synthesize the new second messenger cyclic diadenosine monophosphate (c-di-AMP). Introduction of this mutation into the highly resistant but slower growing strain reduced resistance and increased its growth rate, suggesting a direct connection between the dacA mutation and the phenotypic differences of these strains. Quantification of cellular c-di-AMP revealed that the dacA mutation decreased c-di-AMP levels resulting in reduced autolysis, increased salt tolerance and a reduction in the basal expression of the cell wall stress stimulon. These results indicate that c-di-AMP affects cell envelope-related signalling in S. aureus. The influence of c-di-AMP on growth rate and methicillin resistance in MRSA indicate that altering c-di-AMP levels could be a mechanism by which MRSA strains can increase their fitness levels by reducing their methicillin resistance levels. PMID:24013956

  12. Potential role of Saudi red propolis in alleviating lung damage induced by methicillin resistant Staphylococcus aureus virulence in rats.

    PubMed

    Saddiq, Amna Ali; Mohamed, Azza Mostafa

    2016-07-01

    The aim of this study was to explore the protective impact of aqueous extract of Saudi red propolis against rat lung damage induced by the pathogenic bacteria namely methicillin resistant Staphylococcus aureus (MRSA) ATCC 6538 strain. Infected rats were received a single intraperitoneal (i.p.) injection of bacterial suspension at a dose of 1 X 10(6) CFU / 100g body weight. Results showed that oral administration of an aqueous extract of propolis (50mg/100g body weight) daily for two weeks to infected rats simultaneously with bacterial infection, effectively ameliorated the alteration of oxidative stress biomarker, malondialdehyde (MDA), as well as the antioxidant markers, glutathione peroxidase (GPx) and superoxide dismutase (SOD), in lungs of infected rats compared with infected untreated ones. Also, the used propolis extract successfully modulated the alterations in proinflammatory mediators, tumor necrosis factor-α (TNF- α) and vascular endothelial growth factor (VEGF) in serum. In addition, the propolis extract successfully modulated the oxidative DNA damage and the apoptosis biomarker, caspase 3, in lungs of S aureus infected rats compared with infected untreated animals. The biochemical results were supported by histo-pathological observation of lung tissues. In conclusion, the beneficial prophylactic role of the aqueous extract of Saudi red propolis against lung damage induced by methicillin resistant S aureus may be related to the antioxidant, anti-inflammatory, immunomodulatory and antiapoptosis of its active constituents.

  13. Dissemination of antibiotic resistance in methicillin-resistant Staphylococcus aureus and vancomycin-resistant S aureus strains isolated from hospital effluents.

    PubMed

    Mandal, Santi M; Ghosh, Ananta K; Pati, Bikas R

    2015-12-01

    Vancomycin-resistant Staphylococcus aureus (VRSA) and methicillin-resistant S aureus (MRSA) strains were examined in hospital effluents. Most S aureus strains are resistant to methicillin (MRSA), followed by tetracycline. Approximately 15% of MRSA strains are also resistant to vancomycin (VRSA). All VRSA strains developed a VanR/VanS-regulated 2-component system of VanA-type resistance in their genome. Results indicate that there is a possibility of developing resistance to aminoglycosides by VRSA strains in the near future.

  14. Methicillin-resistant Staphylococcus aureus enterocolitis sequentially complicated with septic arthritis: a case report and review of the literature

    PubMed Central

    2014-01-01

    Background Although most reports describing patients infected with methicillin-resistant Staphylococcus aureus enterocolitis have been published in Japan, this concept remains a matter of debate and diagnostic criteria have not yet been defined. Case presentation The general status of a 74-year-old Japanese man referred to our hospital (day 1) with severe community-acquired pneumococcal pneumonia gradually improved with antibiotic therapy. Thereafter, up to 4 L/day of acute watery diarrhea that started on day 19 was refractory to metronidazole but responded immediately to oral vancomycin. Gram staining stool samples was positive for abundant fecal leukocytes from which dominant methicillin-resistant Staphylococcus aureus (104 CFU/mL) were isolated, suggesting methicillin-resistant Staphylococcus aureus enterocolitis. High fever with methicillin-resistant Staphylococcus aureus bacteremia was evident at day 30, and suppurative right hip arthritis developed around day 71. All methicillin-resistant Staphylococcus aureus strains isolated from stools, blood and aspirated synovial fluid separated in the same manner on pulsed-field gel electrophoresis, as well as two other strains isolated from sputum, belonged to the same clone as sequence type (ST) 764 (complex clonal 5), and carried SCCmec type II. Conclusion The clinical, microbiological and molecular biological findings of this patient indicated methicillin-resistant Staphylococcus aureus enterocolitis that led to septic methicillin-resistant Staphylococcus aureus arthritis. PMID:24405901

  15. Study of Antibiotic Resistance Pattern in Methicillin Resistant Staphylococcus Aureus with Special Reference to Newer Antibiotic

    PubMed Central

    Kaur, Dardi Charan; Chate, Sadhana Sanjay

    2015-01-01

    The worldwide epidemic of antibiotic resistance is in danger of ending the golden age of antibiotic therapy. Resistance impacts on all areas of medicine, and is making successful empirical therapy much more difficult to achieve. Staphylococcus aureus demonstrates a unique ability to quickly respond to each new antibiotic with the development of a resistance mechanism, starting with penicillin, until the most recent, linezolid and daptomycin. Methicillin resistant S. aureus (MRSA) has become endemic today in hospitals worldwide. Resistance to the newer antimicrobial-agents — linezolid, vancomycin, teicoplanin, and daptomycin are been reported and also the fear of pandrug-resistance. This study was carried out to know the antimicrobial resistant pattern of MRSA to newer antibiotic, to know any isolates are extensively-drug resistant (XDR)/pandrug resistant (PDR), inducible macrolide-lincosamide streptogramin B (iMLSB), and mupirocin resistance. Thirty-six MRSA isolates resistant to the routinely tested antibiotic were further tested for list of antibiotic by a group of international experts. Isolates were tested for iMLSB and mupirocin resistance by the disk diffusion method. Of 385 MRSA, 36 (9.35%) isolates of MRSA were resistant to the routinely tested antibiotic. Among these 36 MRSA isolates, none of our isolates were XDR/PDR or showed resistant to anti-MRSA cephalosporins (ceftaroline), phosphonic acids, glycopeptides, glycylcyclines, and fucidanes. Lower resistance was seen in oxazolidinones (2.78%), streptogramins (5.56%), lipopeptide (5.56%). Thirty-four (94.44%) isolates showed constitutive MLSB (cMLSB) resistance and two (5.56%) iMLSB phenotypes. High- and low-level mupirocin resistance were seen in 13 (36.11%) and six (16.67%), respectively. In our study, none of our isolates were XDR or PDR. No resistance was observed to ceftaroline, telavancin, teicoplanin, and vancomycin; but the presence of linezolid resistance (1, 2.28%) and daptomycin resistance (2

  16. High-dose daptomycin plus fosfomycin is safe and effective in treating methicillin-susceptible and methicillin-resistant Staphylococcus aureus endocarditis.

    PubMed

    Miró, José M; Entenza, José M; Del Río, Ana; Velasco, Maria; Castañeda, Ximena; Garcia de la Mària, Cristina; Giddey, Marlyse; Armero, Yolanda; Pericàs, Juan M; Cervera, Carlos; Mestres, Carlos A; Almela, Manuel; Falces, Carlos; Marco, Francesc; Moreillon, Philippe; Moreno, Asuncion

    2012-08-01

    We describe 3 patients with left-sided staphylococcal endocarditis (1 with methicillin-susceptible Staphylococcus aureus [MSSA] prosthetic aortic valve endocarditis and 2 with methicillin-resistant S. aureus [MRSA] native-valve endocarditis) who were successfully treated with high-dose intravenous daptomycin (10 mg/kg/day) plus fosfomycin (2 g every 6 h) for 6 weeks. This combination was tested in vitro against 7 MSSA, 5 MRSA, and 2 intermediately glycopeptide-resistant S. aureus isolates and proved to be synergistic against 11 (79%) strains and bactericidal against 8 (57%) strains. This combination deserves further clinical study.

  17. High-Dose Daptomycin plus Fosfomycin Is Safe and Effective in Treating Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus Endocarditis

    PubMed Central

    Entenza, José M.; del Río, Ana; Velasco, Maria; Castañeda, Ximena; Garcia de la Mària, Cristina; Giddey, Marlyse; Armero, Yolanda; Pericàs, Juan M.; Cervera, Carlos; Mestres, Carlos A.; Almela, Manuel; Falces, Carlos; Marco, Francesc; Moreillon, Philippe

    2012-01-01

    We describe 3 patients with left-sided staphylococcal endocarditis (1 with methicillin-susceptible Staphylococcus aureus [MSSA] prosthetic aortic valve endocarditis and 2 with methicillin-resistant S. aureus [MRSA] native-valve endocarditis) who were successfully treated with high-dose intravenous daptomycin (10 mg/kg/day) plus fosfomycin (2 g every 6 h) for 6 weeks. This combination was tested in vitro against 7 MSSA, 5 MRSA, and 2 intermediately glycopeptide-resistant S. aureus isolates and proved to be synergistic against 11 (79%) strains and bactericidal against 8 (57%) strains. This combination deserves further clinical study. PMID:22644033

  18. Occurrence and characterization of methicillin-resistant staphylococci from bovine mastitis milk samples in Finland

    PubMed Central

    2013-01-01

    Background Methicillin-resistant staphylococci (MRS) are increasingly being isolated in bovine mastitis. The aim of our study was to evaluate the occurrence of MRS in Finnish mastitis milk samples and characterize the MRS isolates using molecular methods. Results Methicillin-resistant S. aureus (MRSA) was a rare finding in bovine mastitis in Finland. Only two out of 135 (1.5%) S. aureus isolates were positive for mec genes. One of these carried mecA and was of spa type t172, SCCmec type IV and ST375, and the other harboured mecC, being spa type t3256, and ST130. MRSA ST375 is common among human MRSA isolates in Finland, but this is the first report in the country of bovine mecC MRSA. In coagulase-negative staphylococci (CoNS) originating from bovine mastitis, methicillin resistance was more common. In the two CoNS collections studied, 5.2% (17/324) and 1.8% (2/110) of the isolates were mecA positive. Eighteen of these were methicillin-resistant S. epidermidis (MRSE), which were divided into 6 separate PFGE clusters. One pulsotype was detected in different parts of the country, indicating clonal spread. Most MRSE (13/18) were of SCCmec type IV, one was of type V and four were non-typeable. Comparison with a human staphylococcal database indicated that bovine MRSE strains were not closely related to human MRSE isolates. Conclusions The occurrence of MRS, especially MRSA, in bovine mastitis in Finland was low. Most methicillin-resistant bovine CoNS are MRSE, and we found evidence of a bovine MRSE strain that may spread clonally. This is the first report of a Finnish bovine isolate of MRSAmecC ST130. The study provides a baseline for further MRS monitoring. PMID:23985065

  19. Successful use of broth microdilution in susceptibility tests for methicillin-resistant (heteroresistant) staphylococci.

    PubMed

    Thornsberry, C; McDougal, L K

    1983-11-01

    We studied the broth microdilution antimicrobial susceptibility testing procedure to see whether it could be made reliable for determining resistance of staphylococci to methicillin, oxacillin, nafcillin, and cephalothin. With 45 selected strains of Staphylococcus aureus and 12 selected strains of Staphylococcus epidermidis we found that the addition of 2% NaCl to cation-supplemented Mueller-Hinton broth permitted us to discriminate reliably between resistant and susceptible organisms. A screening test in which resistant staphylococci grew on agar containing 4% NaCl and methicillin (10 micrograms/ml), oxacillin (6 micrograms/ml), or nafcillin (6 micrograms/ml) incubated at 35 degrees C for 24 h (additional 24 h if no growth) was also reliable. In vitro cephalothin resistance occurred in heteroresistant S. aureus but usually did not occur in heteroresistant S. epidermidis.

  20. Community-acquired methicillin-resistant Staphylococcus aureus in a group home setting.

    PubMed

    Collins, Rebeccah J

    2007-09-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is an infection involving methicillin-resistant Staphylococcus aureus (MRSA) with onset in the community in an individual lacking established health care-associated MRSA risk factors. A 74-year-old group home resident with a history of hypertension and mental retardation presents with a spider bite-like lesion that rapidly progresses to multiple areas of her body. Culture results reveal MRSA. The patient's advanced age and the severity and rapidity of progression of the condition warranted treatment, and options are discussed. Pharmacists should assist in selecting antibiotics for patients with resistant infections and provide strategies for preventing the spread of resistant organisms. Current and complete medical records are critical in the group home setting. The role of the caregiver and the consultant pharmacist in this setting is discussed.

  1. Treating Central Catheter-Associated Bacteremia Due to Methicillin-Resistant Staphylococcus aureus: Beyond Vancomycin.

    PubMed

    Holt, Shannon; Thompson-Brazill, Kelly A; Sparks, E Ryan; Lipetzky, Juliana

    2016-08-01

    Methicillin-resistant Staphylococcus aureus is a frequent cause of hospital-associated infections, including central catheter-associated bacteremia. Vancomycin has been the drug of choice for treating this type of bacteremia for decades in patients who have no contraindications to the antibiotic. However, resistance to vancomycin is an emerging problem. Newer antibiotics approved by the Food and Drug Administration have activity against methicillin-resistant S aureus Some of the antibiotics also have activity against strains of S aureus that are intermediately susceptible or resistant to vancomycin. This article uses a case study to highlight the clinical signs of vancomycin failure and describes the indications for and appropriate use of alternative antimicrobials such as ceftaroline, daptomycin, linezolid, tigecycline, and telavancin. (Critical Care Nurse 2016;36[4]:46-57). PMID:27481801

  2. Methicillin-Resistant Staphylococcus aureus: A Growing Risk in the Hospital and in the Community

    PubMed Central

    Raygada, Jose L.; Levine, Donald P.

    2009-01-01

    Methicillin-resistant Staphylococcus aureus is a common and continuously growing cause of nosocomial and community-acquired infections. The type, disease severity, and clinical outcomes of these infections, as well as the genotypic and susceptibility patterns of the bacteria differ according to the setting in which the infection occurs—a healthcare facility or the community setting. The incidence of these infections in the community setting has been growing consistently in the past decade or so. In addition, resistance to the many current antibiotics used to treat these infections is also growing, further complicating management. Rapid-diagnosis tests and new therapeutic agents are constantly under investigation. The authors review the current understanding of the epidemiology, clinical manifestations, and management of methicillin-resistant Staphylococcus aureus infection, including the growing problem of resistance. In addition, they discuss promising diagnostic and therapeutic alternatives, as well as new control strategies to prevent its transmission or the development of infection among carriers. PMID:25126276

  3. First report of methicillin-resistant Staphylococcus aureus from cage-cultured tilapia (Oreochromis niloticus).

    PubMed

    Atyah, M A S; Zamri-Saad, M; Siti-Zahrah, A

    2010-08-26

    Swabs from the brain, eyes and kidneys of tilapia from 11 farms were collected for a period of 2 years. They were grown on blood agar before cultures of suspected Staphylococcus aureus were subjected to ABI STAPH Detection Kit and PCR for identification. They were then grown on oxacillin resistance screening agar base (ORSAB) and subjected to PCR using the MRSA 17 kb forward and reverse primers to identify the methicillin-resistant S. aureus (MRSA). A total of 559 isolates of Staphylococcus spp. were obtained, from which 198 (35%) isolates were identified as S. aureus. Of the 198 S. aureus isolated from tilapias, 98 (50%) were identified as methicillin-resistant S. aureus (MRSA). Since global spread of multi-drug-resistant bacteria has increased in the past decade, this new finding in fish should be of concern. PMID:20189324

  4. Successful use of broth microdilution in susceptibility tests for methicillin-resistant (heteroresistant) staphylococci.

    PubMed

    Thornsberry, C; McDougal, L K

    1983-11-01

    We studied the broth microdilution antimicrobial susceptibility testing procedure to see whether it could be made reliable for determining resistance of staphylococci to methicillin, oxacillin, nafcillin, and cephalothin. With 45 selected strains of Staphylococcus aureus and 12 selected strains of Staphylococcus epidermidis we found that the addition of 2% NaCl to cation-supplemented Mueller-Hinton broth permitted us to discriminate reliably between resistant and susceptible organisms. A screening test in which resistant staphylococci grew on agar containing 4% NaCl and methicillin (10 micrograms/ml), oxacillin (6 micrograms/ml), or nafcillin (6 micrograms/ml) incubated at 35 degrees C for 24 h (additional 24 h if no growth) was also reliable. In vitro cephalothin resistance occurred in heteroresistant S. aureus but usually did not occur in heteroresistant S. epidermidis. PMID:6643661

  5. Methicillin-Resistant Staphylococcus aureus in Northeastern Scotland in 2003 to 2007: Evolving Strain Distribution and Resistance Patterns▿

    PubMed Central

    Hunt, A. C.; Edwards, B.; Girvan, E. K.; Cosgrove, B.; Edwards, G. F. S.; Gould, I. M.

    2011-01-01

    This study explored strain distribution and resistance patterns of methicillin-resistant Staphylococcus aureus (MRSA) over a 5-year period in northeastern Scotland. We noted a shift in the relative rates of epidemic strains and an increase in community-associated strains. Use of oral antibiotics to eradicate throat carriage may have contributed to trimethoprim resistance, which was observed to increase 10-fold. PMID:21411588

  6. Emergence of rifampicin resistance in methicillin-resistant Staphylococcus aureus isolated at a Turkish university hospital.

    PubMed

    Tosun, Ilknur; Udo, Edet E; Noronha, Bobby; Caylan, Rahmet; Aydin, Faruk; Yetiskul, Serpil; Koksal, Iftihar

    2005-01-01

    Twenty-three rifampicin-resistant methicillin-resistant Staphylococcus aureus (MRSA) isolated in three wards at a university hospital in Turkey between June, 2000, and February, 2001, were studied for their genetic relatedness using a combination of antibiogram, coagulase serotyping, coagulase gene polymorphism (coa-RFLP), and pulsed-field gel electrophoresis (PFGE). They all expressed high-level rifampicin resistance (MIC, >256 mg/L) and were resistant to gentamicin, kanamycin, amikacin, ciprofloxacin, tetracycline, and cadmium acetate and were susceptible to fusidic acid, vancomycin, trimethoprim, and mupirocin. They belonged to the same coagulase serotype (serotype IV) and had identical coa-RFLP patterns. In contrast, PFGE generated nine banding patterns designated type A, types A1-A5, B, C, and D. The most common PFGE pattern (type A) and its subtypes (types A1-A5) were seen in 20 (87%) of the 23 isolates in the three wards. The results demonstrated the acquisition of rifampicin resistance by different MRSA clones and the spread of one clone among patients in the three wards.

  7. Intrarenal abscess caused by community-associated methicillin-resistant Staphylococcus aureus in a transplanted kidney.

    PubMed

    Cheung, C Y; Chan, S Y; Yeung, C S; Kwok, P C; Chak, W L; Wu, T C; Chau, K F

    2016-04-01

    Emergence of multidrug-resistant bacteria is important in solid organ transplant recipients, because it can jeopardize patient and graft survival. Methicillin-resistant Staphylococcus aureus (MRSA) infections are not rare in kidney transplant recipients. On the other hand, infections related to community-associated MRSA (CA-MRSA) strains are seldom reported in the literature. Herein, we report the first patient, to our knowledge, with CA-MRSA renal graft abscess who was successfully treated with drainage and parenteral antibiotics.

  8. Heavy metal and disinfectant resistance genes among livestock-associated methicillin-resistant Staphylococcus aureus isolates.

    PubMed

    Argudín, M Angeles; Lauzat, Birgit; Kraushaar, Britta; Alba, Patricia; Agerso, Yvonne; Cavaco, Lina; Butaye, Patrick; Porrero, M Concepción; Battisti, Antonio; Tenhagen, Bernd-Alois; Fetsch, Alexandra; Guerra, Beatriz

    2016-08-15

    Livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has emerged in animal production worldwide. Most LA-MRSA in Europe belong to the clonal complex (CC) 398. The reason for the LA-MRSA emergence is not fully understood. Besides antimicrobial agents used for therapy, other substances with antimicrobial activity applied in animal feed, including metal-containing compounds might contribute to their selection. Some of these genes have been found in various novel SCCmec cassettes. The aim of this study was to assess the occurrence of metal-resistance genes among a LA-S. aureus collection [n=554, including 542 MRSA and 12 methicillin-susceptible S. aureus (MSSA)] isolated from livestock and food thereof. Most LA-MRSA isolates (76%) carried at least one metal-resistance gene. Among the LA-MRSA CC398 isolates (n=456), 4.8%, 0.2%, 24.3% and 71.5% were positive for arsA (arsenic compounds), cadD (cadmium), copB (copper) and czrC (zinc/cadmium) resistance genes, respectively. In contrast, among the LA-MRSA non-CC398 isolates (n=86), 1.2%, 18.6% and 16.3% were positive for the cadD, copB and czrC genes, respectively, and none were positive for arsA. Of the LA-MRSA CC398 isolates, 72% carried one metal-resistance gene, and the remaining harboured two or more in different combinations. Differences between LA-MRSA CC398 and non-CC398 were statistically significant for arsA and czrC. The czrC gene was almost exclusively found (98%) in the presence of SCCmec V in both CC398 and non-CC398 LA-MRSA isolates from different sources. Regarding the LA-MSSA isolates (n=12), some (n=4) were also positive for metal-resistance genes. This study shows that genes potentially conferring metal-resistance are frequently present in LA-MRSA.

  9. Intercontinental Spread of a Multidrug-Resistant MethicillinResistant Staphylococcus aureus Clone

    PubMed Central

    de Sousa, M. Aires; Sanches, I. Santos; Ferro, M. L.; Vaz, M. J.; Saraiva, Z.; Tendeiro, T.; Serra, J.; de Lencastre, H.

    1998-01-01

    Two hundred ten methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered between 1990 and 1997 from three Portuguese hospitals located in Lisbon and Oporto were analyzed by molecular fingerprinting techniques. The hybridization of ClaI restriction digests with the mecA- and Tn554-specific DNA probes combined with pulsed-field gel electrophoresis documented the abrupt appearance and extensive intrahospital spread of the Brazilian epidemic MRSA clone in the 1995 samples of each one of the three hospitals analyzed—suggesting the intercontinental transfer of this strain from Brazil to Portugal. The appearance of this clone may challenge the dominance of another highly epidemic imported clone—the Iberian MRSA, currently the most widely spread MRSA clone in Portuguese hospitals. PMID:9705398

  10. Economic features of antibiotic resistance: the case of methicillin-resistant Staphylococcus aureus.

    PubMed

    Antonanzas, Fernando; Lozano, Carmen; Torres, Carmen

    2015-04-01

    This paper analyses and updates the economic information regarding methicillin-resistant Staphylococcus aureus (MRSA), including information that has been previously reviewed by other authors, and new information, for the purpose of facilitating health management and clinical decisions. The analysed articles reveal great disparity in the economic burden on MRSA patients; this is mainly due to the diversity of the designs of the studies, as well as the variability of the patients and the differences in health care systems. Regarding prophylactic strategies, the studies do not provide conclusive results that could unambiguously orientate health management. The studies addressing treatments noted that linezolid seems to be a cost-effective treatment for MRSA, mostly because it is associated with a shorter length of stay (LOS) in hospital. However, important variables such as antimicrobial susceptibility, infection type and resistance emergence should be included in these analyses before a conclusion is reached regarding which treatment is the best (most efficient). The reviewed studies found that rapid MRSA detection, using molecular techniques, is an efficient technique to control MRSA. As a general conclusion, the management of MRSA infections implicates important economic costs for hospitals, as they result in higher direct costs and longer LOS than those related to methicillin-susceptible S. aureus (MSSA) patients or MRSA-free patients; there is wide variability in those increased costs, depending on different variables. Moreover, the research reveals a lack of studies on other related topics, such as the economic implications of changes in MRSA epidemiology (community patients and lineages associated with farm animals).

  11. Blood neutrophil bactericidal activity against methicillin-resistant and methicillin-sensitive Staphylococcus aureus during cardiac surgery.

    PubMed

    Mekontso-Dessap, Armand; Honoré, Stéphanie; Kirsch, Matthias; Plonquet, Anne; Fernandez, Eric; Touqui, Lhousseine; Farcet, Jean-Pierre; Soussy, Claude-James; Loisance, Daniel; Delclaux, Christophe

    2005-08-01

    Whether methicillin-resistant Staphylococcus aureus (MRSA) constitutes per se an independent risk factor for morbidity and mortality after surgery as compared with methicillin-sensitive Staphylococcus aureus (MSSA) remains a subject of debate. The aim of this study was to assess whether innate defenses against MRSA and MSSA strains are similarly impaired after cardiac surgery. Both intracellular (isolated neutrophil functions) and extracellular (plasma) defenses of 12 patients undergoing scheduled cardiac surgery were evaluated preoperatively (day 0) and postoperatively (day 3) against two MSSA strains with a low level of catalase secretion and two MRSA strains with a high level of catalase secretion, inasmuch as SA killing by neutrophils relies on oxygen-dependent mechanisms. After surgery, an increase in plasma concentration of IL-10, an anti-inflammatory cytokine able to inhibit reactive oxygen species secretion and bactericidal activity of neutrophils, was evidenced. Despite the fact that univariate analysis suggested a specific impairment of neutrophil functions against MRSA strains, two-way repeated-measures ANOVA failed to demonstrate that the effect of S. aureus phenotype was significant. On the other hand, an increase in type-II secretory phospholipase A2 activity, a circulating enzyme involved in SA lysis, was evidenced and was associated with an enhancement of extracellular defenses (bactericidal activity of plasma) against MRSA. Overall, cardiac surgery and S. aureus phenotype had a significant effect on plasma bactericidal activity. Cardiac surgery was characterized by enhanced antibacterial defenses of plasma, whereas neutrophil killing properties were reduced. The overall effect of S. aureus phenotype on neutrophil functions did not seem significant.

  12. Co-colonization and clonal diversity of methicillin-sensitive and methicillin-resistant Staphylococcus aureus in sows.

    PubMed

    Fetsch, Alexandra; Roesler, Uwe; Kraushaar, Britta; Friese, Anika

    2016-03-15

    Methicillin-susceptible Staphylococcus (S.) aureus (MSSA) and methicillin-resistant S. aureus (MRSA) are colonizers of skin and mucosa. In humans, MSSA and MRSA compete for colonization space in the anterior nares of pig farmers; however, it was also shown that MSSA/MRSA co-colonization is common and one clone can be found rather than differing types of MSSA and MRSA. We investigated the colonization and clonality of both, MSSA and MRSA in pigs over a longer time. Eighteen sows were nasally sampled three times every ten weeks. Additionally, environmental samples were taken. Samples were investigated for MSSA and MRSA, respectively. The spa type was defined from up to five MRSA and MSSA isolates found per sample and sampling time; selected isolates were further investigated by microarray. Three sows (16.7%) were completely negative for MSSA and MRSA. Twelve pigs (66.7%) were irregularly positive for both, MSSA and MRSA over the time, whereas seven out of them (38.9%) were simultaneously colonized. CC398 (t034, t011) MRSA and CC9 (t337, t1430, and t13816) MSSA associated spa types were exclusively found. In 44.4% (n=8) of sows up to two different types of MSSA were present at the same time and sample. Strains of the same clonal lineage showed a high genetic identity despite their origin. Highly identic clones were present in sows and their environment. As conclusion, MSSA/MRSA may not exclude each other in the anterior nares of pigs. Pigs may also carry different clones at the same time.

  13. Co-colonization and clonal diversity of methicillin-sensitive and methicillin-resistant Staphylococcus aureus in sows.

    PubMed

    Fetsch, Alexandra; Roesler, Uwe; Kraushaar, Britta; Friese, Anika

    2016-03-15

    Methicillin-susceptible Staphylococcus (S.) aureus (MSSA) and methicillin-resistant S. aureus (MRSA) are colonizers of skin and mucosa. In humans, MSSA and MRSA compete for colonization space in the anterior nares of pig farmers; however, it was also shown that MSSA/MRSA co-colonization is common and one clone can be found rather than differing types of MSSA and MRSA. We investigated the colonization and clonality of both, MSSA and MRSA in pigs over a longer time. Eighteen sows were nasally sampled three times every ten weeks. Additionally, environmental samples were taken. Samples were investigated for MSSA and MRSA, respectively. The spa type was defined from up to five MRSA and MSSA isolates found per sample and sampling time; selected isolates were further investigated by microarray. Three sows (16.7%) were completely negative for MSSA and MRSA. Twelve pigs (66.7%) were irregularly positive for both, MSSA and MRSA over the time, whereas seven out of them (38.9%) were simultaneously colonized. CC398 (t034, t011) MRSA and CC9 (t337, t1430, and t13816) MSSA associated spa types were exclusively found. In 44.4% (n=8) of sows up to two different types of MSSA were present at the same time and sample. Strains of the same clonal lineage showed a high genetic identity despite their origin. Highly identic clones were present in sows and their environment. As conclusion, MSSA/MRSA may not exclude each other in the anterior nares of pigs. Pigs may also carry different clones at the same time. PMID:26931385

  14. Determination of methicillin-resistant and methicillin-susceptible Staphylococcus aureus bacteria in blood by capillary zone electrophoresis.

    PubMed

    Horká, Marie; Tesařová, Marie; Karásek, Pavel; Růžička, Filip; Holá, Veronika; Sittová, Martina; Roth, Michal

    2015-04-01

    Serious bloodstream infections are a significant complication in critically ill patients. The treatment of these infections has become more difficult because of the increasing prevalence of multiresistant strains, especially methicillin-resistant Staphylococcus aureus (MRSA). Rapid differentiation of low number of MRSA from methicillin-susceptible S. aureus (MSSA) cells (10(1)-10(2) cells mL(-1)) in blood is necessary for fast effective antibiotic therapy. Currently, three groups of techniques, phenotyping, genotyping, and mass spectrometry, are used for MRSA and MSSA strains differentiation. Most of these techniques are time-consuming. PCR and other molecular techniques allow the detection and differentiation between MSSA and MRSA directly from blood cultures. These methods alone are rapid and they have good reproducibility and repeatability. Potential disadvantages of the genotyping methods include their discrimination ability, technical complexity, financial costs, and difficult interpretation of the results. Recently, capillary electrophoresis (CZE) was successfully used to differentiate between the agar-cultivated MRSA and MSSA strains in fused silica capillaries etched with supercritical water and modified with (3-glycidyloxypropyl)trimethoxysilane. The possible use of CZE as a fast and low-cost method for distinguishing between the blood-incubated MRSA or MSSA cells has been tested in this manuscript. Our goal was to test low amounts of bacteria (∼10(2) cell mL(-1)) similar to those in clinical samples. The migration times of the purified blood-incubated cells and the agar-cultivated cells were different from each other. However, their isoelectric point was the same for all strains.

  15. Performance of CHROMagar Selective Medium and Oxacillin Resistance Screening Agar Base for Identifying Staphylococcus aureus and Detecting Methicillin Resistance

    PubMed Central

    Kluytmans, Jan; Van Griethuysen, Arjanne; Willemse, Piet; Van Keulen, Peter

    2002-01-01

    Two new selective media, oxacillin resistance screening agar base (ORSAB) and CHROMagar Staph aureus (CSA), were evaluated for identification of Staphylococcus aureus and for screening of methicillin resistance by addition of antimicrobial agents to these media. A well-defined collection consisting of 1,140 staphylococci was used. A total of 624 were S. aureus, of which 358 were methicillin susceptible and 266 were methicillin resistant, and 516 were coagulase-negative staphylococci. The methicillin-resistant S. aureus (MRSA) strains were selected based on the results of phage typing; 247 different types were included in the analysis. For identification of S. aureus, both media performed better after 24 h than after 48 h. The sensitivities at 24 h were comparable (CSA, 98.6%; ORSAB, 97.1%), but the specificity of CSA was significantly higher (CSA, 97.1%; ORSAB, 92.1%). For screening of methicillin resistance, antibiotic supplements were added to both media. The sensitivity was lower after 24 h (CSA, 58.6%; ORSAB, 84.2%) and increased significantly after 48 h (CSA, 77.5%; ORSAB, 91.4%). At both time intervals ORSAB was significantly more sensitive than CSA. However, the specificities of both media were high after 24 h (CSA, 99.1%; ORSAB, 98.3%) and decreased significantly after 48 h of incubation (CSA, 94.7%; ORSAB, 95.5%). In conclusion, for identification of S. aureus, CSA is more accurate than ORSAB because of a significantly higher specificity. For screening of MRSA, ORSAB performs better than CSA, but the usefulness in clinical practice is limited because a significant number of strains are not detected. PMID:12089266

  16. Detection of methicillin-resistant coagulase-negative staphylococci by the Vitek 2 system.

    PubMed

    Johnson, Kristen N; Andreacchio, Kathleen; Edelstein, Paul H

    2014-09-01

    The accurate performance of the Vitek 2 GP67 card for detecting methicillin-resistant coagulase-negative staphylococci (CoNS) is not known. We prospectively determined the ability of the Vitek 2 GP67 card to accurately detect methicillin-resistant CoNS, with mecA PCR results used as the gold standard for a 4-month period in 2012. Included in the study were 240 consecutively collected nonduplicate CoNS isolates. Cefoxitin susceptibility by disk diffusion testing was determined for all isolates. We found that the three tested systems, Vitek 2 oxacillin and cefoxitin testing and cefoxitin disk susceptibility testing, lacked specificity and, in some cases, sensitivity for detecting methicillin resistance. The Vitek 2 oxacillin and cefoxitin tests had very major error rates of 4% and 8%, respectively, and major error rates of 38% and 26%, respectively. Disk cefoxitin testing gave the best performance, with very major and major error rates of 2% and 24%, respectively. The test performances were species dependent, with the greatest errors found for Staphylococcus saprophyticus. While the 2014 CLSI guidelines recommend reporting isolates that test resistant by the oxacillin MIC or cefoxitin disk test as oxacillin resistant, following such guidelines produces erroneous results, depending on the test method and bacterial species tested. Vitek 2 cefoxitin testing is not an adequate substitute for cefoxitin disk testing. For critical-source isolates, mecA PCR, rather than Vitek 2 or cefoxitin disk testing, is required for optimal antimicrobial therapy. PMID:24951799

  17. A Survey of Staphylococcus sp and its Methicillin Resistance aboard the International Space Station

    NASA Technical Reports Server (NTRS)

    Bassinger, V. J.; Fontenot, S. L.; Castro, V. A.; Ott, C.; Healy, M.; Pierson, D. L.

    2004-01-01

    Background: Within the past few years, methicillin-resistant Staphylococcus aureus has emerged in environments with susceptible hosts in close proximity, such as hospitals and nursing homes. As the International Space Station (ISS) represents a semi-closed environment with a high level of crewmember interaction, an evaluation of isolates of clinical and environmental Staphylococcus aureus and coagulase negative Staphylococcus was performed to determine if this trend was also present in astronauts occupying ISS or on surfaces of the space station itself. Methods: Identification of isolates was completed using VITEK (GPI cards, BioMerieux), 16S ribosomal DNA analysis (MicroSeq 500, ABI), and Rep-PCR DNA fingerprinting (Divemilab, Bacterial Barcodes). Susceptibility tests were performed using VITEK (GPS-105 cards, BioMerieux) and resistance characteristics were evaluated by testing for the presence of the mecA gene (PBP2' MRSA test kit, Oxoid). Results: Rep-PCR analysis indicated the transfer of S. aureus between crewmembers and between crewmembers and ISS surfaces. While a variety of S. aureus were identified from both the crewmembers and environment, evaluations of the microbial population indicated minimal methicillin resistance. Results of this study indicated that within the semi-closed ISS environment, transfer of bacteria between crewmembers and their environment has been occurring, although there was no indication of a high concentration of methicillin resistant Staphylococcus species. Conclusions: While this study suggests that the spread of methicillin resistant S. aureus is not currently a concern aboard ISS, the increasing incidence of Earth-based antibiotic resistance indicates a need for continued clinical and environmental monitoring.

  18. Fitness cost of VanA-type vancomycin resistance in methicillin-resistant Staphylococcus aureus.

    PubMed

    Foucault, Marie-Laure; Courvalin, Patrice; Grillot-Courvalin, Catherine

    2009-06-01

    We have quantified the biological cost of VanA-type glycopeptide resistance due to the acquisition of the resistance operon by methicillin-resistant Staphylococcus aureus (MRSA) from Enterococcus sp. Exponential growths of recipient strain HIP11713, its transconjugant VRSA-1, VRSA-5, and VRSA-6 were compared in the absence or, except for HIP11713, in the presence of vancomycin. Induction of resistance was performed by adding vancomycin in both the preculture and the culture or the culture at only 1/50 the MIC. In the absence of vancomycin, the growth rates of the vancomycin-resistant S. aureus (VRSA) strains were similar to that of susceptible MRSA strain HIP11713. When resistance was induced, and under both conditions, there was a significant reduction of the growth rate of the VRSA strains relative to that of HIP11713 and to those of their noninduced counterparts, corresponding to a ca. 20% to 38% reduction in fitness. Competition experiments between isogenic VRSA-1 and HIP11713 mixed at a 1:1, 1:100, or 100:1 ratio revealed a competitive disadvantage of 0.4% to 3% per 10 generations of the transconjugant versus the recipient. This slight fitness burden can be attributed to the basal level of expression of the van genes in the absence of induction combined with a gene dosage effect due to the presence of the van operon on multicopy plasmids. These data indicate that VanA-type resistance, when induced, is highly costly for the MRSA host, whereas in the absence of induction, its biological cost is minimal. Thus, the potential for the dissemination of VRSA clinical isolates should not be underestimated.

  19. Inactivating Methicillin Resistant Staphylococcus aureus (MRSA) and Other Pathogens by Bacteriocins OR-7 and E 50-52.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Worldwide, reports document the increasing frequency of methicillin resistant Staphylococcus aureus (MRSA) infections. Other human pathogens are recognized as unresponsive to antibiotics of last resort. These previously treatable infections now account for increased numbers of human disease and de...

  20. Inactivating Methicillin Resistant Staphylococcus aureus (MRSA) and other Pathogens by Bacteriocins OR-7 and E 50-52.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Worldwide, reports document the increasing frequency of methicillin resistant Staphylococcus aureus (MRSA) infections. Other human pathogens are recognized as unresponsive to antibiotics of last resort. These previously treatable infections now account for increased numbers of human disease and de...

  1. Genome Sequence of Staphylococcus pseudintermedius Strain E140, an ST71 European-Associated Methicillin-Resistant Isolate.

    PubMed

    Moodley, Arshnee; Riley, Matthew C; Kania, Stephen A; Guardabassi, Luca

    2013-03-07

    We report the first genome sequence of the methicillin-resistant Staphylococcus pseudintermedius (MRSP) strain E140, isolated from a canine bite wound infection in Denmark. This strain represents the dominant clonal lineage associated with canine MRSP infections in Europe.

  2. Community-acquired methicillin-resistant Staphylococcus aureus in Central Australia.

    PubMed

    Stevens, Claire L; Ralph, Anna; McLeod, James E T; McDonald, Malcolm I

    2006-01-01

    To date, there has been scant information about the burden of methicillin-resistant Staphylococcus aureus infections in Central Australia. Our aims were to determine the proportion of Staphylococcus aureus infections due to methicillin-resistant strains in Central Australia, to characterise resistance to non-beta lactam antibiotics and to correlate findings with available demographic information. We retrospectively reviewed S. aureus isolates identified by the Microbiology Laboratory of the Pathology Department, Alice Springs Hospital between September 2005 and February 2006. Multi-resistance was defined as resistance to three or more non-beta lactam antibiotics. We identified the recovery site and extended antibiotic resistance profile of each isolate. Demographic data included place of residence, discharge diagnosis and ethnicity. There were 524 S. aureus isolates: 417 (79.6%) methicillin-sensitive S. aureus, 104 (19.7%) non-multi-resistant MRSA (nmrMRSA) and 3 (0.7%) multi-resistant MRSA (mrMRSA). MRSA accounted for 7/22 (32%) invasive infections and 91/474 (19.2%) cases of staphylococcal skin infections. Aboriginal people comprised 89 per cent (93/104) of patients with nmrMRSA; 57 per cent lived in remote communities, 21 per cent in suburban Alice Springs, and 18 per cent in Alice Springs Town Camps. Six per cent (6/104) of nmrMRSA were hospital-acquired. Of the nmrMRSA isolates, 57 per cent (59/104) were resistant to erythromycin and 7 per cent (7/104) to fusidic acid. All MRSA isolates were susceptible to co-trimoxazole. In conclusion, Central Australia has high rates of community-acquired nmrMRSA and low rates of multi-resistant MRSA. Erythromycin resistance in S. aureus is also common. These findings should prompt the review of antimicrobial prescribing guidelines for the region, especially for treatment of skin and soft tissue infections.

  3. Control of an outbreak of an epidemic methicillin-resistant Staphylococcus aureus also resistant to mupirocin.

    PubMed

    Irish, D; Eltringham, I; Teall, A; Pickett, H; Farelly, H; Reith, S; Woodford, N; Cookson, B

    1998-05-01

    An epidemic methicillin-resistant Staphlococcus aureus (EMRSA-3) appeared in a District hospital in June 1989 as part of a regional outbreak. The dynamics of the outbreak were complex and involved patient transfer between hospitals and wards. Control measures followed UK guidelines and included the use of nasal mupirocin. During these efforts a mupirocin-resistant MRSA [MuMRSA: mupirocin minimum inhibitor concentration (MIC) > 256 mg/L] emerged, probably in a patient who had been given eight mupirocin courses over nine months. The MuMRSA had a narrower phage-typing pattern than EMRSA-3, but was indistinguishable by pulsed-field gel electrophoresis of SmaI chromosomal restriction enzyme digests and its susceptibility pattern to other antibiotics. The results of in vitro curing and gene probing indicated that mupirocin resistance was encoded on a 48 Md plasmid. MuMRSA spread occurred in 12 patients and 11 staff. The affected patients were nursed on the same ward. The strain was eradicated from patients with oral ciprofloxacin and rifampicin, triclosan skin treatment and nasal fusidic acid and bacitracin cream. The control of the outbreak had significant medical, social and financial implications. Fortunately, there were alternative topical agents to mupirocin, an agent which has played such a key role in MRSA eradication in recent years.

  4. Molecular Characterization and Antimicrobial Resistance Profile of Methicillin-Resistant Staphylococcus aureus in Retail Chicken.

    PubMed

    Sallam, Khalid Ibrahim; Abd-Elghany, Samir Mohammed; Elhadidy, Mohamed; Tamura, Tomohiro

    2015-10-01

    The emergence of livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) in food-producing animals is of increasing interest, raising questions about the presence of MRSA in food of animal origin and potential sources of transmission to humans via the food chain. In this study, the prevalence, molecular characterization, virulence factors, and antimicrobial susceptibility patterns of MRSA isolates from 200 retail raw chicken samples in Egypt were determined. MRSA was detected by positive amplification of the mecA gene in 38% (76 of 200) of chicken samples analyzed. This represents a potential public health threat in Egypt, as this contamination rate seems to be the highest among other studies reported worldwide. Furthermore, genes encoding α-hemolysin (hla) and staphylococcal enterotoxins (sea, seb, and sec) were detected in all of the 288 MRSA isolates. Nonetheless, none of the strains tested carried tst, the gene encoding toxic shock syndrome toxin 1. Antimicrobial resistance of MRSA isolates was most frequently detected against penicillin (93.4%), ampicillin (88.9%), and cloxacillin (83.3%). These results suggest that retail chicken might be a significant potential source for transmission of multidrug-resistant and toxigenic S. aureus in Egypt. This underlines the need for stricter hygienic measures in chicken production in Egypt to minimize the risk of transmission of these strains to consumers. To the best of our knowledge, this is the first study that reports the isolation and molecular characterization of MRSA in retail chicken samples in Egypt.

  5. Molecular Characterization and Antimicrobial Resistance Profile of Methicillin-Resistant Staphylococcus aureus in Retail Chicken.

    PubMed

    Sallam, Khalid Ibrahim; Abd-Elghany, Samir Mohammed; Elhadidy, Mohamed; Tamura, Tomohiro

    2015-10-01

    The emergence of livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) in food-producing animals is of increasing interest, raising questions about the presence of MRSA in food of animal origin and potential sources of transmission to humans via the food chain. In this study, the prevalence, molecular characterization, virulence factors, and antimicrobial susceptibility patterns of MRSA isolates from 200 retail raw chicken samples in Egypt were determined. MRSA was detected by positive amplification of the mecA gene in 38% (76 of 200) of chicken samples analyzed. This represents a potential public health threat in Egypt, as this contamination rate seems to be the highest among other studies reported worldwide. Furthermore, genes encoding α-hemolysin (hla) and staphylococcal enterotoxins (sea, seb, and sec) were detected in all of the 288 MRSA isolates. Nonetheless, none of the strains tested carried tst, the gene encoding toxic shock syndrome toxin 1. Antimicrobial resistance of MRSA isolates was most frequently detected against penicillin (93.4%), ampicillin (88.9%), and cloxacillin (83.3%). These results suggest that retail chicken might be a significant potential source for transmission of multidrug-resistant and toxigenic S. aureus in Egypt. This underlines the need for stricter hygienic measures in chicken production in Egypt to minimize the risk of transmission of these strains to consumers. To the best of our knowledge, this is the first study that reports the isolation and molecular characterization of MRSA in retail chicken samples in Egypt. PMID:26408138

  6. The Evaluation of Methicillin Resistance in Staphylococcus aboard the International Space Station

    NASA Technical Reports Server (NTRS)

    Ott, C. M.; Bassinger, V. J.; Fontenot, S. L.; Castro, V. A.; Pierson, D. L.

    2005-01-01

    The International Space Station (ISS) represents a semi-closed environment with a high level of crewmember interaction. As community-acquired methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a health concern in environments with susceptible hosts in close proximity, an evaluation of isolates of clinical and environmental Staphylococcus aureus and coagulase negative Staphylococcus was performed to determine if this trend was also present in astronauts aboard ISS or the space station itself. Rep-PCR fingerprinting analysis of archived ISS isolates confirmed our earlier studies indicating a transfer of S. aureus between crewmembers. In addition, this fingerprinting also indicated a transfer between crewmembers and their environment. While a variety of S. aureus were identified from both the crewmembers and the environment, phenotypic evaluations indicated minimal methicillin resistance. However, positive results for the Penicillin Binding Protein, indicative of the presence of the mecA gene, were detected in multiple isolates of archived Staphylococcus epidermidis and Staphylococcus haemolyticus. Phenotypic analysis of these isolates confirmed their resistance to methicillin. While MRSA has not been isolated aboard ISS, the potential exists for the transfer of the gene, mecA, from coagulase negative environmental Staphylococcus to S. aureus creating MRSA strains. This study suggests the need to expand environmental monitoring aboard long duration exploration spacecraft to include antibiotic resistance profiling.

  7. Methicillin resistance in Staphylococcus aureus strains isolated from food and wild animal carcasses in Italy.

    PubMed

    Traversa, A; Gariano, G R; Gallina, S; Bianchi, D M; Orusa, R; Domenis, L; Cavallerio, P; Fossati, L; Serra, R; Decastelli, L

    2015-12-01

    Following the detection of methicillin-resistant Staphylococcus aureus (MRSA) ST398 in food-producing animals, both livestock and wildlife, and derived products, are considered potential sources of MRSA in humans. There is a paucity of data on MRSA in foods in Italy, and the data regarding wild animals are particularly scarce. A total of 2162 food samples collected during official monitoring activities in 2008 were analyzed for the detection of S. aureus. Also, samples from 1365 wild animals collected by the National Reference Center for Wild Animal Diseases in 2003-2009 were subjected to anatomopathological examination. S. aureus isolates were processed for phenotypic and molecular methicillin resistance determinations. S. aureus was found in 2.0% of wild animal carcasses and in 3.2% of wild boar lymph nodes: none showed methicillin resistance. The prevalence of S. aureus in food was 17.1%. Two MRSA strains, both from bulk tank milk (prevalence 0.77%) were isolated: the strains were resistant to tetracycline, had spa-type t899, and were negative for the Panton-Valentine leukocidin gene. The low prevalence of MRSA suggests that the risk of transmission to humans via food is limited. However, attention should be paid to the cattle food chain, which may be a potential route of transmission of LA-MRSA. PMID:26338130

  8. Methicillin resistance in Staphylococcus aureus strains isolated from food and wild animal carcasses in Italy.

    PubMed

    Traversa, A; Gariano, G R; Gallina, S; Bianchi, D M; Orusa, R; Domenis, L; Cavallerio, P; Fossati, L; Serra, R; Decastelli, L

    2015-12-01

    Following the detection of methicillin-resistant Staphylococcus aureus (MRSA) ST398 in food-producing animals, both livestock and wildlife, and derived products, are considered potential sources of MRSA in humans. There is a paucity of data on MRSA in foods in Italy, and the data regarding wild animals are particularly scarce. A total of 2162 food samples collected during official monitoring activities in 2008 were analyzed for the detection of S. aureus. Also, samples from 1365 wild animals collected by the National Reference Center for Wild Animal Diseases in 2003-2009 were subjected to anatomopathological examination. S. aureus isolates were processed for phenotypic and molecular methicillin resistance determinations. S. aureus was found in 2.0% of wild animal carcasses and in 3.2% of wild boar lymph nodes: none showed methicillin resistance. The prevalence of S. aureus in food was 17.1%. Two MRSA strains, both from bulk tank milk (prevalence 0.77%) were isolated: the strains were resistant to tetracycline, had spa-type t899, and were negative for the Panton-Valentine leukocidin gene. The low prevalence of MRSA suggests that the risk of transmission to humans via food is limited. However, attention should be paid to the cattle food chain, which may be a potential route of transmission of LA-MRSA.

  9. Genotypic Diversity of Methicillin-Resistant Coagulase-Negative Staphylococci Isolated from Inpatients and Outpatients.

    PubMed

    Talebi, Malihe; Shafiee, Mohammad; Sadeghi, Javad; Moghadam, Nasrin Asghari; Saifi, Mahnaz; Pourshafie, Mohammad R

    2016-03-01

    We investigated the prevalence of methicillin-resistant coagulase-negative staphylococci (MRCoNS) isolated from hospitalized patients and outpatients (OP). Out of 350 staphylococcal isolates collected from three hospitals, 190 were coagulase-negative staphylococci (CoNS). These isolates were subjected to antimicrobial susceptibility tests, detection of mecA, and pulsed-field gel electrophoresis (PFGE) typing. Among the 190 isolated CoNS, Staphylococcus epidermidis (47.3%) and Staphylococcus haemolyticus (44.2%) were the most prevalent species. Other CoNS species that were isolated were Staphylococcus saprophyticus (2.1%), Staphylococcus warneri (2.1%), Staphylococcus simulans (1.6%), Staphylococcus capitis (1.1%), Staphylococcus schleiferi (1.1%), and Staphylococcus hominis (0.5%). The rate of resistance to methicillin was 60% with 58 (50%) S. epidermidis and 55 (49%) S. haemolyticus. The rate of resistance to 13 antibiotics tested with the lowest and highest to chloramphenicol and penicillin, respectively. High clonal diversity with different PFGE patterns was obtained for methicillin-resistant S. epidermidis and S. haemolyticus by 32 and 31 types, respectively. Our results indicated that the dissemination of MRCoNS is widespread in Tehran. The majority of these isolates showed distinct genotyping patterns. At the same time, the common patterns were found among the MRCoNS obtained from outpatient and inpatient isolates, suggestive of an epidemiological link. PMID:26248114

  10. Screening for detection of methicillin-resistant Staphylococcus aureus in Doon Valley Hospitals, Uttarakhand.

    PubMed

    Talwar, Amitabh; Saxena, Seema; Kumar, Ajay

    2016-03-01

    Present study was conducted to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) among patients at various hospitals in Doon Valley, Uttrakhand. A total of 300 nasal swabs (male patients: 177, female patients: 123) were subjected to bacteriological investigation following established protocol. Isolates were verified by mannitol fermentation, Gram staining, DNAse test and coagulase positivity. S aureus was isolated in 111 (37%) participants (M: 37%, F: 36.5%). Out of 111 S. aureus isolates, 38 (34.2%) were methicillin resistant (MRSA). Among them, 25 (38%) were male and 13 (29%) were from female. Highest MRSA colonization rate was found among dialysis ward patients (55.5%), followed by burn ward (32.5%) and general medical ward (22.7%) patients. The study also revealed that administration of recent antibiotic was chief predisposing factor for MRSA colonization. High MRSA carriage rate found in this study indicates demand for standard infection control to curb transmission. PMID:27097444

  11. Successful Use of Daptomycin in a Preterm Neonate With Persistent Methicillin-Resistant Staphylococcus epidermidis Bacteremia

    PubMed Central

    2015-01-01

    There is limited information regarding the use of daptomycin in the neonatal population, and dosage adjustments for neonates with renal dysfunction. We report on the successful use of daptomycin in a 1-month-old, former 24-week gestation neonate with persistent methicillin-resistant Staphylococcus epidermidis (MRSE) bacteremia and impaired renal function. We also review the available literature supporting daptomycin use in the neonatal period. Daptomycin peak and trough serum levels were obtained immediately prior to and 60 minutes after the fifth dose. While vancomycin remains the drug of choice for methicillin-resistant Staphylococcal infections, due to increasing reports of treatment failures, alternative therapies are recommended. Based on mounting evidence, daptomycin may be considered an option in persistently bacteremic neonates who fail vancomycin therapy, although further investigation is warranted. PMID:25859172

  12. Screening for detection of methicillin-resistant Staphylococcus aureus in Doon Valley Hospitals, Uttarakhand.

    PubMed

    Talwar, Amitabh; Saxena, Seema; Kumar, Ajay

    2016-03-01

    Present study was conducted to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) among patients at various hospitals in Doon Valley, Uttrakhand. A total of 300 nasal swabs (male patients: 177, female patients: 123) were subjected to bacteriological investigation following established protocol. Isolates were verified by mannitol fermentation, Gram staining, DNAse test and coagulase positivity. S aureus was isolated in 111 (37%) participants (M: 37%, F: 36.5%). Out of 111 S. aureus isolates, 38 (34.2%) were methicillin resistant (MRSA). Among them, 25 (38%) were male and 13 (29%) were from female. Highest MRSA colonization rate was found among dialysis ward patients (55.5%), followed by burn ward (32.5%) and general medical ward (22.7%) patients. The study also revealed that administration of recent antibiotic was chief predisposing factor for MRSA colonization. High MRSA carriage rate found in this study indicates demand for standard infection control to curb transmission.

  13. Characterization of methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase-negative Staphylococcus spp. isolated from US West Coast public marine beaches

    PubMed Central

    Soge, Olusegun O.; Meschke, John S.; No, David B.; Roberts, Marilyn C.

    2009-01-01

    Objectives The aim of this study was to isolate and characterize methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus spp. (MRCoNS) from marine water and intertidal beach sand from public beaches in Washington State, USA. Methods Fifty-one staphylococci from Washington State beaches were characterized using antimicrobial susceptibility testing, carriage of acquired tetracycline and/or macrolide resistance genes, staphylococcal cassette chromosome mec (SCCmec) typing, the BBL Crystal™ Gram-Positive ID System and/or 16S rRNA sequencing, coagulase test and multilocus sequence typing (MLST) for MRSA. Results Five multidrug-resistant MRSA SCCmec type I, of which three were MLST type ST45, one ST59 and one a new MLST type, ST1405, plus one susceptible non-typeable (NT) MRSA ST30 were characterized. Thirty-three MRCoNS isolates, representing 21 strains from 9 Staphylococcus spp., carried a range of SCCmec types [I (2), II (6), III (3), V (2), I/II (1) and NT (7)] and varied in their antibiotic susceptibility to other antibiotic classes and carriage of acquired tetracycline/macrolide resistance gene(s). MRSA and MRCoNS donors co-transferred tet(M) and erm(A) genes to an Enterococcus faecalis recipient at a frequency of 10−8. Conclusions This is the first report of MRSA and MRCoNS isolated from marine water and intertidal beach sand. The MLST types and antibiotic carriage of five MRSA isolates were similar to hospital MRSA isolates rather than US community-acquired MRSA isolates. Our results suggest that public marine beaches may be a reservoir for transmission of MRSA to beach visitors as well as an ecosystem for exchange of antibiotic resistance genes among staphylococci and related genera. PMID:19837712

  14. Results after Late Polymicrobial, Gram-negative, and Methicillin-resistant Infections in Knee Arthroplasty

    PubMed Central

    Esteban, Jaime; García-Rey, Eduardo

    2010-01-01

    Background Previous studies of knee arthroplasty infections caused by high-virulence organisms suggest poor outcomes. Polymicrobial and Gram-negative infections are less studied. Questions/purposes This study compared the results of treatment of knee arthroplasty infections by single versus polymicrobial isolates, Gram-positive versus Gram-negative, and methicillin-resistant versus -sensitive Staphylococci. Methods We prospectively followed 47 patients with late knee arthroplasty infections. The mean age was 72 years (range, 20–87 years). The treatment protocol included two-stage exchange and a combination of two oral antibiotics given for 6 months. Minimum followup was 1 year (average, 4.8 ± 3 years; range, 1–12 years). Control of the infection was judged by absence of clinical, serologic, and radiologic signs of infection. The functional outcome was evaluated by Knee Society score at the last followup. Results Infection was controlled in all 15 patients with polymicrobial and in 28 of 32 (88%) with monomicrobial infections, in eight of nine patients with Gram-negative and in 35 of 38 (92%) with Gram-positive isolates. Control was also achieved in 22 of 25 patients (88%) infected by methicillin-resistant Staphylococci and in 14 of 14 by methicillin-sensitive Staphylococci. The Knee Society scores averaged 81-63 in patients with polymicrobial infections and were higher than in monomicrobial infections (75-52). The mean KSS was 85-59 in Gram-negative infections compared to 75-55 in Gram-positive infections. The mean KSS was similar in methicillin-resistant (78-54) and methicillin-sensitive Staphylococci (73-56) infections. Conclusions Polymicrobial and Gram-negative infections can be controlled in late knee arthroplasty infections. On the other hand, infections by methicillin-resistant Staphylococci are less likely to be controlled by the regimens we used. Level of Evidence Level II, prognostic study. See Guidelines for Authors for a complete

  15. Endemic methicillin-resistant Staphylococcus aureus: Nurses' risk perceptions and attitudes.

    PubMed

    Pedro, Ana Luisa; Sousa-Uva, António; Pina, Elaine

    2014-10-01

    Dissemination of methicillin-resistant Staphylococcus aureus (MRSA) remains one of the most difficult challenges for prevention, control, and treatment of health care-associated infections. A survey and interviews were conducted on nurses from a hospital center. We found that most nurses' perceived risk of acquiring MRSA related to themselves (72%), other nurses (88.5%), and patients (97.8%). This perception influences attitudes, leading to compliance with the existing recommendations.

  16. Hypochlorite killing of community-associated methicillin-resistant Staphylococcus aureus.

    PubMed

    Fisher, Randall G; Chain, Rebecca L; Hair, Pamela S; Cunnion, Kenji M

    2008-10-01

    We tested in vitro hypochlorite (bleach) killing of community-associated methicillin-resistant Staphylococcus aureus isolates to determine optimal concentration and duration. For all isolates maximal killing, >3-log decrease in colony forming units (CFU), was found after 5 minutes in 2.5 microL/mL bleach. We estimate that 2.5 microL/mL bleach is approximately one-half cup of bleach in one-quarter tub of water.

  17. Methicillin-Resistant Staphylococcus schleiferi Subspecies coagulans Infection in a Patient With Hepatocellular Carcinoma

    PubMed Central

    Swe, Thein; Naing, Akari Thein; Baqui, AAMA; Khillan, Ratesh

    2016-01-01

    To our knowledge and literature search, Staphylococcus schleiferi subspecies coagulans infection in human beings has rarely been described in the medical literature. Furthermore, we believe that this is a first detailed case report of methicillin-resistant Staphylococcus schleiferi subspecies coagulans infection in a patient with hepatocellular carcinoma. Because of the possible association of Staphylococcus schleiferi infection and immunosuppression, any isolates of this bacterium in human beings should be presumed to be pathogenic, unless proven otherwise. PMID:27734018

  18. Chloride anion transporters inhibit growth of methicillin-resistant Staphylococcus aureus (MRSA) in vitro.

    PubMed

    Share, Andrew I; Patel, Khushali; Nativi, Cristina; Cho, Eun J; Francesconi, Oscar; Busschaert, Nathalie; Gale, Philip A; Roelens, Stefano; Sessler, Jonathan L

    2016-06-18

    A series of aminopyrrolic receptors were tested as anion transporters using POPC liposome model membranes. Many were found to be effective Cl(-) transporters and to inhibit clinical strains of Staphylococcus aureus growth in vitro. The best transporters proved effective against the methicillin-resistant Staphylococcus aureus (MRSA) strains, Mu50 and HP1173. Tris-thiourea tren-based chloride transporters were also shown to inhibit the growth of S. aureus in vitro.

  19. The Rise of Methicillin-Resistant Staphylococcus aureus in U.S. Correctional Populations

    PubMed Central

    Malcolm, Bianca

    2011-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging threat to public health, especially in correctional settings. Outbreaks have been seen in jails and prisons in Mississippi, California, Texas, and Georgia in recent years. Also, many correctional settings have seen an increase in MRSA infection greater than in the general population. This article examines the lessons that have been learned about MRSA in correctional settings and ponders what is yet to be learned about this disease in these populations. PMID:21571749

  20. Hypochlorite killing of community-associated methicillin-resistant Staphylococcus aureus.

    PubMed

    Fisher, Randall G; Chain, Rebecca L; Hair, Pamela S; Cunnion, Kenji M

    2008-10-01

    We tested in vitro hypochlorite (bleach) killing of community-associated methicillin-resistant Staphylococcus aureus isolates to determine optimal concentration and duration. For all isolates maximal killing, >3-log decrease in colony forming units (CFU), was found after 5 minutes in 2.5 microL/mL bleach. We estimate that 2.5 microL/mL bleach is approximately one-half cup of bleach in one-quarter tub of water. PMID:18756186

  1. Mannitol-negative methicillin-resistant Staphylococcus aureus from nasal swab specimens in Brazil.

    PubMed

    dos Santos, Danielle Caldeira Martins; da Costa, Thaina Miranda; Rabello, Renata Fernandes; Alves, Fábio Aguiar; de Mondino, Silvia Susana Bona

    2015-06-01

    The isolation of mannitol-negative methicillin-resistant Staphylococcus aureus from nasal swabs is reported. Among the 59 isolates, 9 (15%) isolates were mannitol-negative; all of these isolates were categorized as staphylococcal cassette chromosome mec (SCCmec) type IVa. This report emphasizes that mannitol fermentation on mannitol salt agar should not be used as the sole criterion when screening nasal swab specimens for S. aureus.

  2. Community-acquired methicillin resistant Staphylococcus aureus in a women's collegiate basketball team.

    PubMed

    Stevens, Michael P; Bearman, Gonzalo; Rosato, Adriana; Edmond, Michael

    2008-10-01

    Community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) infections are becoming increasingly frequent, and cutaneous disease with this organism is often seen in otherwise healthy organized sports participants. A case of CA-MRSA skin and soft tissue infection in a female collegiate basketball player is presented, and screening and management of her team is discussed. Interestingly, multiple MRSA strains were discovered on testing of the team, raising concern that the prevalence of colonization in this population may be high.

  3. Antibiotics and bioactive natural products in treatment of methicillin resistant Staphylococcus aureus: A brief review

    PubMed Central

    Kali, Arunava

    2015-01-01

    Infections caused by Staphylococcus aureus strains with Methicillin resistance are associated with increased mortality and morbidity, aggressive course, multiple drug resistance and hospital outbreaks. Several first and second line antibiotics are rapidly becoming ineffective for treatment due to emergence of resistance. Extracts of medicinal plants are rich source of unique phytochemicals. Plants used in traditional medicine have been reported to have significant anti-MRSA activity. The objective of this review is to provide a brief overview of antibiotics as well as anti-MRSA natural products and their future prospect. PMID:26009690

  4. Dissimilarity of ccrAB gene sequences between methicillin-resistant Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus among bovine isolates in Korea

    PubMed Central

    Park, Young Kyung; Paik, Young Hwan; Yoon, Jang Won; Fox, Lawrence K.

    2013-01-01

    The sequences of the ccrAB genes from bovine-, canine- and chicken-originating methicillin-resistant Staphylococcus (S.) epidermidis (MRSE) and bovine methicillin-resistant Staphylococcus (S.) aureus (MRSA) were compared to investigate the frequency of intra-species horizontal transfer of the staphylococcal cassette chromosome mec (SCCmec) complex. Nineteen MRSE strains were isolated from bovine milk, chickens, and dogs, and their genetic characteristics were investigated by multilocus sequence typing and SCCmec typing. Among the animal MRSE strains, the most frequent SCCmec type was type IV, which consisted of the type B mec complex and ccrAB type 2. The ccrA2 and ccrB2 genes were sequenced from the bovine, chicken and canine MRSE strains and compared with those of the bovine MRSA strains. The sequences generally clustered as MRSA and MRSE groups, regardless of the animal source. Additionally, no bovine MRSE sequence was associated with the bovine MRSA groups. Although most of the bovine MRSE and MRSA isolates possessed SCCmec type IV sequences, our results suggest that the intra-species gene transfer of the SCCmec complex between bovine S. aureus and bovine S. epidermidis strains is not a frequent event. PMID:23820199

  5. Dissimilarity of ccrAB gene sequences between methicillin-resistant Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus among bovine isolates in Korea.

    PubMed

    Park, Young Kyung; Paik, Young Hwan; Yoon, Jang Won; Fox, Lawrence K; Hwang, Sun Young; Park, Yong Ho

    2013-01-01

    The sequences of the ccrAB genes from bovine-, canine- and chicken-originating methicillin-resistant Staphylococcus (S.) epidermidis (MRSE) and bovine methicillin-resistant Staphylococcus (S.) aureus (MRSA) were compared to investigate the frequency of intra-species horizontal transfer of the staphylococcal cassette chromosome mec (SCCmec) complex. Nineteen MRSE strains were isolated from bovine milk, chickens, and dogs, and their genetic characteristics were investigated by multilocus sequence typing and SCCmec typing. Among the animal MRSE strains, the most frequent SCCmec type was type IV, which consisted of the type B mec complex and ccrAB type 2. The ccrA2 and ccrB2 genes were sequenced from the bovine, chicken and canine MRSE strains and compared with those of the bovine MRSA strains. The sequences generally clustered as MRSA and MRSE groups, regardless of the animal source. Additionally, no bovine MRSE sequence was associated with the bovine MRSA groups. Although most of the bovine MRSE and MRSA isolates possessed SCCmec type IV sequences, our results suggest that the intra-species gene transfer of the SCCmec complex between bovine S. aureus and bovine S. epidermidis strains is not a frequent event.

  6. Evaluation of different methods for the detection of methicillin resistance in coagulase-negative staphylococci.

    PubMed

    Jarløv, J O; Busch-Sørensen, C; Espersen, F; Mortensen, I; Hougaard, D M; Rosdahl, V T

    1997-08-01

    The efficacy of 19 agar diffusion methods for the detection of methicillin resistance among coagulase-negative staphylococci (CoNS) within 24 h was evaluated. A total of 359 CoNS isolates were tested, of which 204 were Staphylococcus epidermidis. In 164 isolates, the presence of mecA was investigated; 61 strains were mecA-positive and 103 were mecA-negative by Southern blot analysis. Based on the best agreement shown with the mecA determination (94%) among four agar dilution assays for determining methicillin MIC, an assay with Columbia agar supplemented with NaCl and incubation with a heavy bacterial inoculum of 10(5)-10(6) cfu/spot was used as the reference MIC method. The best agar diffusion results were obtained with a 1 microg oxacillin disc on Columbia agar with 4.5% NaCl supplement. With this method, 99% of S. epidermidis and 94% of non-S. epidermidis were in agreement with the MIC determination. However, Columbia (without NaCl), Mueller-Hinton and Isosensitest agars were almost as useful when a 1 microg oxacillin disc was used. The zone breakpoints for S. epidermidis were, in general, considerably larger than those for other CoNS species and, consequently, differentiation according to species is recommended. Furthermore, resistance to other antibiotics, such as gentamicin and erythromycin, makes methicillin resistance highly likely.

  7. Marinopyrrole Derivatives as Potential Antibiotic Agents against Methicillin-Resistant Staphylococcus aureus (II)

    PubMed Central

    Cheng, Chunwei; Liu, Yan; Song, Hao; Pan, Lili; Li, Jerry; Qin, Yong; Li, Rongshi

    2013-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a major problem, causing severe and intractable infections worldwide. MRSA is resistant to all beta-lactam antibiotics, and alternative treatments are limited. A very limited number of new antibiotics have been discovered over the last half-century, novel agents for the treatment of MRSA infections are urgently needed. Marinopyrrole A was reported to show antibiotic activity against MRSA in 2008. After we reported the first total synthesis of (±)-marinopyrrole A, we designed and synthesized a series of marinopyrrole derivatives. Our structure activity relationship (SAR) studies of these novel derivatives against a panel of Gram-positive pathogens in antibacterial assays have revealed that a para-trifluoromethyl analog (33) of marinopyrrole A is ≥63-, 8-, and 4-fold more potent than vancomycin against methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-susceptible Staphylococcus aureus (MSSA) and MRSA, respectively. The results provide valuable information in the search for new-generation antibiotics. PMID:23955285

  8. [Comparison of chosen methods for identification of methicillin-resistant Staphylococcus aureus].

    PubMed

    Kaczmarek, Agnieszka; Budzyńska, Anna; Gospodarek, Eugenia

    2009-01-01

    The aim of this study was to estimate effectiveness of methicillin-resistant S. aureus identification using screening method with oxacillin (6 microg/ml), latex agglutination test--Slidex MRSA Detection and a chromogenic agar medium--MRSA ID. The investigation were carried out on 120 S. aureus strains isolated from clinical materials of patients hospitalized in the University Hospital at the L. Rydygier Collegium Medicum in Bydgoszcz, University of Nicolaus Copernicus in Torún. Consistency of results between chromogenic medium and latex agglutination test amounted 97.5%, chromogenic medium and screening method--96.7%. Identical correspondence of results took a stand in case screening method and latex agglutination test. Results consistency of detecting methicillin resistance in S. aureus strains between this three methods concerned 95.8% strains. Our investigation demonstrated 96.7% sensitivity and 100% specificity for MRSA ID medium for the detection of methicillin resistance. The sensitivity of MRSA-Screen was 95.0% and its specificity reached 100%. The sensitivity and specificity of screening method amounted 96.7%.

  9. Evaluation of different methods for the detection of methicillin resistance in coagulase-negative staphylococci.

    PubMed

    Jarløv, J O; Busch-Sørensen, C; Espersen, F; Mortensen, I; Hougaard, D M; Rosdahl, V T

    1997-08-01

    The efficacy of 19 agar diffusion methods for the detection of methicillin resistance among coagulase-negative staphylococci (CoNS) within 24 h was evaluated. A total of 359 CoNS isolates were tested, of which 204 were Staphylococcus epidermidis. In 164 isolates, the presence of mecA was investigated; 61 strains were mecA-positive and 103 were mecA-negative by Southern blot analysis. Based on the best agreement shown with the mecA determination (94%) among four agar dilution assays for determining methicillin MIC, an assay with Columbia agar supplemented with NaCl and incubation with a heavy bacterial inoculum of 10(5)-10(6) cfu/spot was used as the reference MIC method. The best agar diffusion results were obtained with a 1 microg oxacillin disc on Columbia agar with 4.5% NaCl supplement. With this method, 99% of S. epidermidis and 94% of non-S. epidermidis were in agreement with the MIC determination. However, Columbia (without NaCl), Mueller-Hinton and Isosensitest agars were almost as useful when a 1 microg oxacillin disc was used. The zone breakpoints for S. epidermidis were, in general, considerably larger than those for other CoNS species and, consequently, differentiation according to species is recommended. Furthermore, resistance to other antibiotics, such as gentamicin and erythromycin, makes methicillin resistance highly likely. PMID:9301990

  10. Marinopyrrole derivatives as potential antibiotic agents against methicillin-resistant Staphylococcus aureus (II).

    PubMed

    Cheng, Chunwei; Liu, Yan; Song, Hao; Pan, Lili; Li, Jerry; Qin, Yong; Li, Rongshi

    2013-08-15

    Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a major problem, causing severe and intractable infections worldwide. MRSA is resistant to all beta-lactam antibiotics, and alternative treatments are limited. A very limited number of new antibiotics have been discovered over the last half-century, novel agents for the treatment of MRSA infections are urgently needed. Marinopyrrole A was reported to show antibiotic activity against MRSA in 2008. After we reported the first total synthesis of (±)-marinopyrrole A, we designed and synthesized a series of marinopyrrole derivatives. Our structure activity relationship (SAR) studies of these novel derivatives against a panel of Gram-positive pathogens in antibacterial assays have revealed that a para-trifluoromethyl analog (33) of marinopyrrole A is ≥ 63-, 8-, and 4-fold more potent than vancomycin against methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-susceptible Staphylococcus aureus (MSSA) and MRSA, respectively. The results provide valuable information in the search for new-generation antibiotics.

  11. Controlling methicillin resistant Staphyloccocus aureus and Pseudomonas aeruginosa wound infections with a novel biomaterial.

    PubMed

    Martineau, Lucie; Davis, Stephen C; Peng, Henry T; Hung, Andy

    2007-01-01

    Wound infections, especially those associated with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, offer considerable challenges for clinicians. Our laboratory has recently developed novel composite biomaterials (DRDC) for wound dressing applications, and demonstrated their in vitro bactericidal efficacy. In the present study, we assessed the proliferation of planktonic and sessile Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus in porcine full-thickness wounds covered for up to 48 h with either saline- or mafenide acetate-loaded DRDC puffs and meshes. All biomaterials were applied 4 h following bacterial inoculation of the wounds with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, to allow colonization of the tissues and initiation of biofilm formation. The drug-loaded biomaterials eradicated both the planktonic and biofilm bacteria in the wounds within 24 h (p <. 05), irrespective of the bacterial strain or architecture of the dressing. While the wound bioburdens increased in the ensuing 24 h, they remained approximately 2 log(10) colony-forming units (CFU) below (p <. 05) their respective baseline values. Similarly, less than 4 log(10) CFU was recovered in the drug-loaded DRDC biomaterials throughout the study. These data show that the DRDC puffs and meshes are effective in delivering certain medications, such as antimicrobial agents, to the wound bed, suggesting considerable value of this material for treating wounds, especially those with irregular shapes, contours, and depths.

  12. Resistance to methicillin of coagulase-negative staphylococci (CNS) isolated from bovine mastitis.

    PubMed

    Bochniarz, M; Wawron, W; Szczubial, M

    2013-01-01

    The aim of this study was to determine the mechanisms of staphylococcal resistance to methicillin. CNS (n = 100 isolates) were prepared from the mammary inflammatory secretions of 86 cows from farms located in the Lublin region. Methicillin-resistant isolates constituted 20.0% of all CNS. Staphylococcus sciuri (n=8) and Staphylococcus xylosus (n=6) were most abundant, followed by Staphylococcus chromogenes (n=3), Staphylococcus haemolyticus (n=2) and Staphylococcus warned (n=1). The mecA gene was found in 50.0% of MRCNS (10.0% of all CNS isolates) belonging to two species: S. sciuri and S. xylosus. All mecA-positive isolates contained the protein of low affinity to penicillin (penicillin-binding protein 2a - PBP2a). The enzyme hydrolysing the beta-lactam ring in antibiotics was detected in 40.0% of MRCNS; 10.0% of MRCNS isolates were characterised by the presence of the mecA gene and ability to produce beta-lactamase. The remaining 20.0% of MRCNS isolates showing phenotypic resistance to methicillin were mecA gene-negative and were not able to produce beta-lactamase. PMID:24597303

  13. Chlorhexidine resistance in methicillin-resistant Staphylococcus aureus or just an elevated MIC? An in vitro and in vivo assessment.

    PubMed

    Cookson, B D; Bolton, M C; Platt, J H

    1991-10-01

    Chlorhexidine (Hibiscrub; ICI) is generally accepted to be effective as an antiseptic hand wash for methicillin-susceptible Staphylococcus aureus (MSSA), but there is dispute whether the chlorhexidine MIC for methicillin-resistant S. aureus (MRSA) strains is higher than that for MSSA strains and, indeed, whether it is relevant. In addition, the link between resistance to chlorhexidine, gentamicin, and "nucleic acid-binding" compounds (NAB; which code, in particular, for propamidine isethionate and ethidium bromide) requires clarification. We performed chlorhexidine MIC and rate of kill tests on a number of MSSA and MRSA isolates. Two gentamicin-resistant MRSA isolates without NAB plasmids were more susceptible (0.25 and 0.5 microgram/ml) than four of eight MSSA that we tested (range, 0.25 to 2 microgram/ml). Chlorhexidine MICs were higher (4 to 8 micrograms/ml) for seven distinct MRSA isolates with plasmids conveying resistance to gentamicin and NAB (GNAB). Curing of the GNAB plasmid from MRSA strains resulted in a fall in the MIC (1 to 3.3 micrograms/ml), but no consistent fall in killing by chlorhexidine was observed. No effect on the chlorhexidine MIC or killing was observed when we cured strains of methicillin resistance. GNAB plasmid transfer resulted in a rise in the chlorhexidine MIC for the strains but not consistent fall in killing by chlorhexidine. Ethical approval was granted for 10 volunteers to each have a methicillin-susceptible, GNAB-resistant, derived transcipient and its GNAB-susceptible isogenic parent applied to separate sites in an in vivo skin test; no significant difference was seen in survival rates after the application of chlorhexidine. These results suggest that chlorhexidine appears to be as effective as a hand-washing agent for MRSA isolates with or with out NAB plasmids as it is for MSSA isolates.

  14. Detection of Methicillin Resistance and Various Virulence Factors in Staphylococcus aureus Strains Isolated from Nasal Carriers

    PubMed Central

    Dağı, Hatice Türk; Fındık, Duygu; Demirel, Gamze; Arslan, Uğur

    2015-01-01

    Background: Staphylococus aureus can be found as a commensal on skin and nasal flora or it may cause local and invasive infections. S. aureus has a large number of virulence factors. Aims: To investigate the methicillin resistance and frequency of various virulence factors in S. aureus nasal isolates. Study Design: Descriptive study. Methods: Nasal samples collected from university students were cultured in media. S. aureus was identified by conventional methods and the Staphyloslide latex test (Becton Dickinson, Sparks, USA). Antibiotic susceptibility tests were conducted, and the methicillin resistance was determined. The mecA, nuc, pvl and staphylococcal toxin genes were examined by polymerase chain reaction (PCR). Results: S. aureus was isolated in 104 of 600 (17.3%) nasal samples. In total, 101 (97.1%) S. aureus isolates were methicillin-sensitive and the remaining 3 (2.9%) were methicillin-resistant. Furthermore, all but five isolates carried at least one staphylococcal enterotoxin gene, with seg being predominant. The tst and eta genes were determined in 29 (27.9%), and 3 (2.9%) isolates, respectively. None of the S. aureus isolates harbored see, etb, and pvl genes. Conclusion: A moderate rate of S. aureus carriage and low frequency of MRSA were detected in healthy students. S. aureus isolates had a high prevalence of staphylococcal enterotoxin genes and the tst gene. In this study, a large number of virulence factors were examined in S. aureus nasal isolates, and the data obtained from this study can be used for monitoring the prevalence of virulence genes in S. aureus strains isolated from nasal carriers. PMID:26167341

  15. Characterization of Methicillin-Resistant and -Susceptible Staphylococcal Isolates from Bovine Milk in Northwestern China

    PubMed Central

    Li, Longping; Zhou, Luoxiong; Wang, Lihong; Xue, Huping; Zhao, Xin

    2015-01-01

    Emergence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) in bovine milk is a major public health concern. The primary purpose of this research was to determine molecular genetic characteristics and antibiotic resistance of staphylococcal isolates recovered from milk of mastitic cows in the Shaanxi Province in Northwestern China. One hundred and thirteen methicillin-susceptible Staphylococcus aureus (MSSA), one mecA-positive and phenotype-positive MRSA, seven mecA- and mecC- negative but phenotype-positive MRSA and two MR-CoNS including one oxacillin-susceptible mecA-positive Staphylococcus haemolyticus (OS-MRSH) and one mecA-positive and methicillin-resistant Staphylococcus epidermidis (MRSE) isolates were recovered from 214 quarter milk samples on 4 dairy farms. All above 123 isolates were subjected to antibiotic resistance profiling. S. aureus isolates were also genotyped using the spa typing and the multilocus sequence typing (MLST). Eight MRSA and 2 MR-CoNS isolates were additionally tested for SCCmec types. Resistance was common among isolates against ampicillin or penicillin (80.5%), kanamycin (68.3%), gentamicin (67.5%), tetracycline (43.9%) and chloramphenicol (30.1%). However, no isolate was resistant to vancomycin or teicoplanin. Twenty, 29 and 58 isolates showed resistance to 1, 2 or more than 2 antibiotics, respectively. The predominant multidrug resistance profile was penicillin/ampicillin/kanamycin/gentamicin/tetracycline (46 isolates). Most S. aureus isolates belonged to spa types t524 (n = 63), t11772 (a new type, n = 31) and t4207 (n = 15). At the same time, MLST types ST71 (n = 67) and ST2738 (a new type, n = 45) were identified as dominant sequence types. The mecA-positive and phenotype-positive MRSA isolate had a composite genotype t524-ST71-SCCmecIVa, while 7 mecA-negative but phenotype-positive MRSA isolates were all t524-ST71. The OS-MRSH isolate contained a type V

  16. Characterization of methicillin-resistant and -susceptible staphylococcal isolates from bovine milk in northwestern china.

    PubMed

    Li, Longping; Zhou, Luoxiong; Wang, Lihong; Xue, Huping; Zhao, Xin

    2015-01-01

    Emergence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) in bovine milk is a major public health concern. The primary purpose of this research was to determine molecular genetic characteristics and antibiotic resistance of staphylococcal isolates recovered from milk of mastitic cows in the Shaanxi Province in Northwestern China. One hundred and thirteen methicillin-susceptible Staphylococcus aureus (MSSA), one mecA-positive and phenotype-positive MRSA, seven mecA- and mecC- negative but phenotype-positive MRSA and two MR-CoNS including one oxacillin-susceptible mecA-positive Staphylococcus haemolyticus (OS-MRSH) and one mecA-positive and methicillin-resistant Staphylococcus epidermidis (MRSE) isolates were recovered from 214 quarter milk samples on 4 dairy farms. All above 123 isolates were subjected to antibiotic resistance profiling. S. aureus isolates were also genotyped using the spa typing and the multilocus sequence typing (MLST). Eight MRSA and 2 MR-CoNS isolates were additionally tested for SCCmec types. Resistance was common among isolates against ampicillin or penicillin (80.5%), kanamycin (68.3%), gentamicin (67.5%), tetracycline (43.9%) and chloramphenicol (30.1%). However, no isolate was resistant to vancomycin or teicoplanin. Twenty, 29 and 58 isolates showed resistance to 1, 2 or more than 2 antibiotics, respectively. The predominant multidrug resistance profile was penicillin/ampicillin/kanamycin/gentamicin/tetracycline (46 isolates). Most S. aureus isolates belonged to spa types t524 (n = 63), t11772 (a new type, n = 31) and t4207 (n = 15). At the same time, MLST types ST71 (n = 67) and ST2738 (a new type, n = 45) were identified as dominant sequence types. The mecA-positive and phenotype-positive MRSA isolate had a composite genotype t524-ST71-SCCmecIVa, while 7 mecA-negative but phenotype-positive MRSA isolates were all t524-ST71. The OS-MRSH isolate contained a type V

  17. [Antimicrobial spectrum of ceftaroline. In vitro activity against methicillin-resistant staphylococci].

    PubMed

    Cercenado, Emilia; Morosini, María Isabel

    2014-03-01

    Because of the increase in bacterial resistance, there is a need for new antimicrobial agents. In particular, Staphylococcus aureus is a frequent cause of severe infections and has an extraordinary capacity to develop antibiotic multiresistance, including resistance to glycopeptides, linezolid, and daptomycin. Although the incidence of methicillin-resistant S. aureus (MRSA) seems to have stabilized in the last few years, its wide dissemination in healthcare settings and in the community is a cause of concern. Ceftaroline is a new broad-spectrum cephalosporin with bactericidal activity against Gram-positive bacteria, including MRSA and multidrug-resistant Streptococcus pneumoniae. In addition, this drug is active against staphylococci showing resistance to glycopeptides, linezolid, and daptomycin. The ceftaroline MIC90 against MRSA ranges from 0.5-2mg/L and that against methicillin-resistant coagulase-negative staphylococci is 0.5mg/L. Ceftaroline has also good activity against respiratory pathogens including Haemophilus influenzae and Moraxella catarrhalis. Although this drug is active against Enterobacteriaceae, it does not retain activity when these isolates produce extended-spectrum beta-lactamases, carbapenemases or hyperproduce AmpC. Ceftaroline is not active against nonfermentative Gram-negative bacilli. Ceftaroline is an interesting addition to the therapeutic armamentarium against MRSA and constitutes an important option for the treatment of polymicrobial infections caused by multidrug-resistant Gram-positive microorganisms.

  18. The Staphylococcus aureus Methicillin Resistance Factor FmtA Is a d-Amino Esterase That Acts on Teichoic Acids

    PubMed Central

    Rahman, Muhammad M.; Hunter, Howard N.; Prova, Shamina; Verma, Vidhu; Qamar, Aneela

    2016-01-01

    ABSTRACT The methicillin resistance factor encoded by fmtA is a core member of the Staphylococcus aureus cell wall stimulon, but its function has remained elusive for the past two decades. First identified as a factor that affects methicillin resistance in S. aureus strains, FmtA was later shown to interact with teichoic acids and to localize to the cell division septum. We have made a breakthrough in understanding FmtA function. We show that FmtA hydrolyzes the ester bond between d-Ala and the backbone of teichoic acids, which are polyglycerol-phosphate or polyribitol-phosphate polymers found in the S. aureus cell envelope. FmtA contains two conserved motifs found in serine active-site penicillin-binding proteins (PBPs) and β-lactamases. The conserved SXXK motif was found to be important for the d-amino esterase activity of FmtA. Moreover, we show that deletion of fmtA (ΔfmtA) led to higher levels of d-Ala in teichoic acids, and this effect was reversed by complementation of ΔfmtA with fmtA. The positive charge on d-Ala partially masks the negative charge of the polyol-phosphate backbone of teichoic acids; hence, a change in the d-Ala content will result in modulation of their charge. Cell division, biofilm formation, autolysis, and colonization are among the many processes in S. aureus affected by the d-Ala content and overall charge of the cell surface teichoic acids. The esterase activity of FmtA and the regulation of fmtA suggest that FmtA functions as a modulator of teichoic acid charge, thus FmtA may be involved in S. aureus cell division, biofilm formation, autolysis, and colonization. PMID:26861022

  19. Rapid Identification of Methicillin-Resistant Staphylococcus aureus (MRSA) by the Vitek MS Saramis system.

    PubMed

    Shan, Weiguang; Li, Jiaping; Fang, Ying; Wang, Xuan; Gu, Danxia; Zhang, Rong

    2016-01-01

    A rapid, sensitive, and accurate Vitek MS assay was developed to distinguish clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) from clinical isolates of methicillin-sensitive Staphylococcus aureus (MSSA) by developing an in-house knowledgebase of SuperSpectra. Three unique peaks, including peaks at 2305.6 and 3007.3 Da specific to MRSA, and 6816.7 Da specific to MSSA, were selected for differentiating MRSA and MSSA. This assay accurately identified 84 and 91% of clinical MRSA and MSSA strains out of the total 142 clinically acquired S. aureus strains that were tested. This method will greatly improve the efficiency of single clinical sample identification of MRSA, thereby facilitating a reduction in the transmission of MRSA in clinical settings.

  20. Epidemic neonatal gentamicin-methicillin--resistant Staphylococcus aureus infection associated with nonspecific topical use of gentamicin.

    PubMed

    Graham, D R; Correa-Villasenor, A; Anderson, R L; Vollman, J H; Baine, W B

    1980-12-01

    One hundred sixteen infants in an intensive care nursery acquired Staphylococcus aureus resistant to gentamicin and methicillin; 54 patients acquired S. aureus sensitive to gentamicin and methicillin. Topical application of gentamicin ointment was significantly associated with acquisition of GMRS. Of 78 infants who acquired GMRS, 38 had received GmO before GMRS was first cultured, whereas only one of 49 infants with GMSS had previously received GmO (P = 8.6 X 10(-8)). Infants with GMRS were also more likely than patients with GMSS to have had a lower mean birth weight, Apgar score, and gestational age; systemic antibiotic therapy and incubator care were significantly prolonged for patients with GMRS, but these factors did not explain susceptibility to GMRS infection. Multivariate logistic regression analysis showed that use of GmO was the single most important risk factor.

  1. Transcriptome Analysis of Responses to Rhodomyrtone in Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Sianglum, Wipawadee; Srimanote, Potjanee; Taylor, Peter W.; Rosado, Helena; Voravuthikunchai, Supayang P.

    2012-01-01

    Rhodomyrtone, purified from Rhodomyrtus tomentosa (Aiton) Hassk, exhibits a high degree of potency against methicillin-resistant Staphylococcus aureus (MRSA). We recently demonstrated that exposure of MRSA to a subinhibitory concentration (0.174 µg/ml) of rhodomyrtone resulted in the alteration of expression of several functional classes of bacterial proteins. To provide further insight into the antibacterial mode of action of this compound, we determined the impact of exposure to rhodomyrtone on the gene transcriptional profile of MRSA using microarray analysis. Exposure of MRSA to subinhibitory concentrations (0.5MIC; 0.5 µg/ml) of rhodomyrtone revealed significant modulation of gene expression, with induction of 64 genes and repression of 35 genes. Prominent changes in response to exposure to rhodomyrtone involved genes encoding proteins essential to metabolic pathways and processes such as amino acid metabolism, membrane function, ATP-binding cassette (ABC) transportation and lipoprotein and nucleotide metabolism. Genes involved in the synthesis of the aspartate family of amino acids, in particular proteins encoded by the dap operon were prominent. The diaminopimelate (DAP) biosynthetic pathway is the precursor of lysine synthesis and is essential for peptidoglycan biosynthesis. However, phenotypic analysis of the peptidoglycan amino acid content of rhodomyrtone-treated MRSA did not differ significantly from that extracted from control cells. Genes involved in the biosynthesis of amino acids and peptidoglycan, and a high affinity ATP-driven K (+) transport system, were investigated by quantitative reverse transcription-PCR (qRT-PCR) using EMRSA-16 1, 4, or 18 h after exposure to rhodomyrtone and in general the data concurred with that obtained by microarray, highlighting the relevance of the DAP biosynthetic pathway to the mode of action of rhodomyrtone. PMID:23029218

  2. Towards the understanding of resistance mechanisms in clinically isolated trimethoprim-resistant, methicillin-resistant Staphylococcus aureus dihydrofolate reductase.

    PubMed

    Frey, Kathleen M; Lombardo, Michael N; Wright, Dennis L; Anderson, Amy C

    2010-04-01

    Resistance to therapeutics such as trimethoprim-sulfamethoxazole has become an increasing problem in strains of methicillin-resistant Staphylococcus aureus (MRSA). Clinically isolated trimethoprim-resistant strains reveal a double mutation, H30N/F98Y, in dihydrofolate reductase (DHFR). In order to develop novel and effective therapeutics against these resistant strains, we evaluated a series of propargyl-linked antifolate lead compounds for inhibition of the mutant enzyme. For the propargyl-linked antifolates, the F98Y mutation generates minimal (between 1.2- and 6-fold) losses of affinity and the H30N mutation generates greater losses (between 2.4- and 48-fold). Conversely, trimethoprim affinity is largely diminished by the F98Y mutation (36-fold) and is not affected by the H30N mutation. In order to elucidate a mechanism of resistance, we determined a crystal structure of a complex of this double mutant with a lead propargyl-linked antifolate. This structure suggests a resistance mechanism consistent both for the propargyl-linked class of antifolates and for trimethoprim that is based on the loss of a conserved water-mediated hydrogen bond.

  3. Towards the Understanding of Resistance Mechanisms in Clinically Isolated Trimethoprim-resistant, Methicillin-resistant Staphylococcus aureus Dihydrofolate Reductase

    SciTech Connect

    Frey, K.; Lombardo, M; Wright, D; Anderson, A

    2010-01-01

    Resistance to therapeutics such as trimethoprim-sulfamethoxazole has become an increasing problem in strains of methicillin-resistant Staphylococcus aureus (MRSA). Clinically isolated trimethoprim-resistant strains reveal a double mutation, H30N/F98Y, in dihydrofolate reductase (DHFR). In order to develop novel and effective therapeutics against these resistant strains, we evaluated a series of propargyl-linked antifolate lead compounds for inhibition of the mutant enzyme. For the propargyl-linked antifolates, the F98Y mutation generates minimal (between 1.2- and 6-fold) losses of affinity and the H30N mutation generates greater losses (between 2.4- and 48-fold). Conversely, trimethoprim affinity is largely diminished by the F98Y mutation (36-fold) and is not affected by the H30N mutation. In order to elucidate a mechanism of resistance, we determined a crystal structure of a complex of this double mutant with a lead propargyl-linked antifolate. This structure suggests a resistance mechanism consistent both for the propargyl-linked class of antifolates and for trimethoprim that is based on the loss of a conserved water-mediated hydrogen bond.

  4. Penicillin-Binding Protein 2a of Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Fishovitz, Jennifer; Hermoso, Juan A.; Chang, Mayland

    2014-01-01

    Summary High-level resistance to β-lactam antibiotics in methicillin-resistant Staphylococcus aureus (MRSA) is due to expression of penicillin-binding protein 2a (PBP2a), a transpeptidase that catalyzes cell-wall crosslinking in the face of the challenge by β-lactam antibiotics. The activity of this protein is regulated by allostery at a site 60 Å distant from the active site, where crosslinking of cell wall takes place. This review discusses the state of knowledge on this important enzyme of cell-wall biosynthesis in MRSA. PMID:25044998

  5. Survey of methicillin-resistant Staphylococcus aureus strains from two hospitals in El Paso, Texas.

    PubMed

    O'Brien, Frances G; Lim, Tien Tze; Winnett, David C; Coombs, Geoffrey W; Pearson, Julie C; Delgado, Alejandro; Langevin, Mark J; Cantore, Stephanie A; Gonzalez, Leti; Gustafson, John E

    2005-06-01

    Seventy-one percent of 76 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from two medical centers in El Paso, Texas, represent three similar pulsed-field gel electrophoresis types. Overall, six pulsed-field types were identified represented by multilocus sequence/staphylococcal chromosomal cassette DNA mec (SCCmec) types: ST5-MRSA-II; ST36-MRSA-II; ST8 (untypeable SCCmec); and a newly described clonal cluster 8 strain, ST507-MRSA-IV. This study demonstrates the presence of multiple-antibiotic-resistant epidemic MRSA clones in El Paso.

  6. Structure-Function Studies of the Staphylococcal Methicillin Resistance Antirepressor MecR2*

    PubMed Central

    Arêde, Pedro; Botelho, Tiago; Guevara, Tibisay; Usón, Isabel; Oliveira, Duarte C.; Gomis-Rüth, F. Xavier

    2013-01-01

    Methicillin resistance in Staphylococcus aureus is elicited by the MecI-MecR1-MecA axis encoded by the mec locus. Recently, MecR2 was also identified as a regulator of mec through binding of the methicillin repressor, MecI. Here we show that plasmid-encoded full-length MecR2 restores resistance in a sensitive S. aureus mecR2 deletion mutant of the resistant strain N315. The crystal structure of MecR2 reveals an N-terminal DNA-binding domain, an intermediate scaffold domain, and a C-terminal dimerization domain that contributes to oligomerization. The protein shows structural similarity to ROK (repressors, open reading frames, and kinases) family proteins, which bind DNA and/or sugar molecules. We found that functional cell-based assays of three point mutants affecting residues participating in sugar binding in ROK proteins had no effect on the resistance phenotype. By contrast, MecR2 bound short double-stranded DNA oligonucleotides nonspecifically, and a deletion mutant affecting the N-terminal DNA-binding domain showed a certain effect on activity, thus contributing to resistance less than the wild-type protein. Similarly, a deletion mutant, in which a flexible segment of intermediate scaffold domain had been replaced by four glycines, significantly reduced MecR2 function, thus indicating that this domain may likewise be required for activity. Taken together, these results provide the structural basis for the activity of a methicillin antirepressor, MecR2, which would sequester MecI away from its cognate promoter region and facilitate its degradation. PMID:23733184

  7. Community-acquired methicillin-resistant Staphylococcus aureus: community transmission, pathogenesis, and drug resistance.

    PubMed

    Yamamoto, Tatsuo; Nishiyama, Akihito; Takano, Tomomi; Yabe, Shizuka; Higuchi, Wataru; Razvina, Olga; Shi, Da

    2010-08-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is able to persist not only in hospitals (with a high level of antimicrobial agent use) but also in the community (with a low level of antimicrobial agent use). The former is called hospital-acquired MRSA (HA-MRSA) and the latter community-acquired MRSA (CA-MRSA). It is believed MRSA clones are generated from S. aureus through insertion of the staphylococcal cassette chromosome mec (SCCmec), and outbreaks occur as they spread. Several worldwide and regional clones have been identified, and their epidemiological, clinical, and genetic characteristics have been described. CA-MRSA is likely able to survive in the community because of suitable SCCmec types (type IV or V), a clone-specific colonization/infection nature, toxin profiles (including Pantone-Valentine leucocidin, PVL), and narrow drug resistance patterns. CA-MRSA infections are generally seen in healthy children or young athletes, with unexpected cases of diseases, and also in elderly inpatients, occasionally surprising clinicians used to HA-MRSA infections. CA-MRSA spreads within families and close-contact groups or even through public transport, demonstrating transmission cores. Re-infection (including multifocal infection) frequently occurs, if the cores are not sought out and properly eradicated. Recently, attention has been given to CA-MRSA (USA300), which originated in the US, and is growing as HA-MRSA and also as a worldwide clone. CA-MRSA infection in influenza season has increasingly been noted as well. MRSA is also found in farm and companion animals, and has occasionally transferred to humans. As such, the epidemiological, clinical, and genetic behavior of CA-MRSA, a growing threat, is focused on in this study. PMID:20336341

  8. Methicillin Resistance Alters the Biofilm Phenotype and Attenuates Virulence in Staphylococcus aureus Device-Associated Infections

    PubMed Central

    Rudkin, Justine K.; Schaeffer, Carolyn R.; Lohan, Amanda J.; Tong, Pin; Loftus, Brendan J.; Pier, Gerald B.; Fey, Paul D.; Massey, Ruth C.; O'Gara, James P.

    2012-01-01

    Clinical isolates of Staphylococcus aureus can express biofilm phenotypes promoted by the major cell wall autolysin and the fibronectin-binding proteins or the icaADBC-encoded polysaccharide intercellular adhesin/poly-N-acetylglucosamine (PIA/PNAG). Biofilm production in methicillin-susceptible S. aureus (MSSA) strains is typically dependent on PIA/PNAG whereas methicillin-resistant isolates express an Atl/FnBP-mediated biofilm phenotype suggesting a relationship between susceptibility to β-lactam antibiotics and biofilm. By introducing the methicillin resistance gene mecA into the PNAG-producing laboratory strain 8325-4 we generated a heterogeneously resistant (HeR) strain, from which a homogeneous, high-level resistant (HoR) derivative was isolated following exposure to oxacillin. The HoR phenotype was associated with a R602H substitution in the DHHA1 domain of GdpP, a recently identified c-di-AMP phosphodiesterase with roles in resistance/tolerance to β-lactam antibiotics and cell envelope stress. Transcription of icaADBC and PNAG production were impaired in the 8325-4 HoR derivative, which instead produced a proteinaceous biofilm that was significantly inhibited by antibodies against the mecA-encoded penicillin binding protein 2a (PBP2a). Conversely excision of the SCCmec element in the MRSA strain BH1CC resulted in oxacillin susceptibility and reduced biofilm production, both of which were complemented by mecA alone. Transcriptional activity of the accessory gene regulator locus was also repressed in the 8325-4 HoR strain, which in turn was accompanied by reduced protease production and significantly reduced virulence in a mouse model of device infection. Thus, homogeneous methicillin resistance has the potential to affect agr- and icaADBC-mediated phenotypes, including altered biofilm expression and virulence, which together are consistent with the adaptation of healthcare-associated MRSA strains to the antibiotic-rich hospital environment in which they are

  9. The Prevalence, Genotype and Antimicrobial Susceptibility of High- and Low-Level Mupirocin Resistant Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Park, Se Young; Kim, Shin Moo

    2012-01-01

    Background Mupirocin has been used for the treatment of skin infections and eradication of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA). The increased use of this antibiotic has been accompanied by outbreaks of MRSA that are resistant to mupirocin. Objective This study aims to determine the prevalence, genotype and antimicrobial susceptibility of mupirocin-resistant MRSA from 4 Korean hospitals. Methods A total 193 MRSA clinical isolates were collected from four university hospitals. Antimicrobial susceptibility tests, including mupirocin, and pulsed-field gel electrophoresis (PFGE) pattern analysis were performed. Results Overall, 27 of the 193 (14.1%) MRSA isolates were resistant to mupirocin. All of the (A) hospital isolates showed high-level (HL) mupirocin resistance and the low-level (LL) mupirocin resistant strains were from three other hospitals. The PFGE patterns of 16 mupirocin-resistant isolates were divided into 5 clusters (1-5), and the nine HL mupirocin-resistant isolates belonged to cluster 1. Both the HL and LL mupirocin-resistant MRSA isolates were susceptible to vancomycin and rifampin, but they were resistant to ciprofloxacin, clindamycin and tetracycline. The erythromycin and fusidic acid resistance rates were different between the HL and LL resistant isolates. Conclusion HL mupirocin-resistant isolates that could transfer this resistance to other bacteria were detected and these isolates were clonally related. The emergence of mupirocin resistant isolates emphasizes the importance of using antibiotics judiciously and carefully monitoring the prevalence of mupirocin resistance. PMID:22363153

  10. Detection of methicillin-resistant Staphylococcus aureus (MRSA) using the NanoLantern Biosensor

    NASA Astrophysics Data System (ADS)

    Strohsahl, Christopher M.; Miller, Benjamin L.; Krauss, Todd D.

    2009-02-01

    Staphylococcus aureus is a leading cause of human illness, and has developed the remarkable ability to resist the bactericidal capabilities of many of the world's leading antibiotics (i.e. MRSA). In an effort to enable rapid detection and treatment of MRSA infections, we have developed a DNA detection technology termed the NanoLantern(TM). The NanoLantern(TM) biosensor technology is based on the simple immobilization of a fluorophore-terminated DNA hairpin onto a gold chip. This produces a label-free sensor that allows for a positive response to be obtained without extensive processing of the sample, saving cost and increasing accuracy. We will also discuss a newly developed method of partial gene analysis, used to develop a DNA hairpin probe that is capable of detecting the presence of the mecR gene, a gene necessary for methicillin resistance to be present in S. aureus, with 100% sequence specificity. The successful incorporation of this probe into the NanoLantern(TM) platform, along with the concomitant development of the paired PCR assay has allowed for the successful detection of methicillin-resistance directly from a culture of S. aureus. These results represent an important step forward in terms of developing the ability to rapidly and effectively detect the presence of antibiotic resistance in bacterial infections.

  11. Identification in methicillin-susceptible Staphylococcus hominis of an active primordial mobile genetic element for the staphylococcal cassette chromosome mec of methicillin-resistant Staphylococcus aureus.

    PubMed

    Katayama, Yuki; Takeuchi, Fumihiko; Ito, Teruyo; Ma, Xiao Xue; Ui-Mizutani, Yoko; Kobayashi, Ichizo; Hiramatsu, Keiichi

    2003-05-01

    We previously reported that the methicillin resistance gene mecA is carried by a novel type of mobile genetic element, SCCmec (staphylococcal cassette chromosome mec), in the chromosome of methicillin-resistant Staphylococcus aureus (MRSA). These elements are precisely excised from the chromosome and integrated into a specific site on the recipient chromosome by a pair of recombinase proteins encoded by the cassette chromosome recombinase genes ccrA and ccrB. In the present work, we detected homologues of the ccr genes in Staphylococcus hominis type strain GIFU12263 (equivalent to ATCC 27844), which is susceptible to methicillin. Sequence determination revealed that the ccr homologues in S. hominis were type 1 ccr genes (ccrA1 and ccrB1) that were localized on a genetic element structurally very similar to SCCmec except for the absence of the methicillin-resistance gene, mecA. This genetic element had mosaic-like patterns of homology with extant SCCmec elements, and we designated it SCC(12263) and considered it a type I staphylococcal cassette chromosome (SCC). The ccrB1 gene identified in the S. hominis strain is the first type 1 ccrB gene discovered to retain its function through the excision process as judged by two criteria: (i) SCC(12263) was spontaneously excised during cultivation of the strain and (ii) introduction of the S. hominis ccrB1 into an MRSA strain carrying a type I SCCmec whose ccrB1 gene is inactive generated SCCmec excisants at a high frequency. The existence of an SCC without a mec determinant is indicative of a staphylococcal site-specific mobile genetic element that serves as a vehicle of transfer for various genetic markers between staphylococcal species.

  12. Fluoroquinolone Impact on Nasal Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Colonization Durations in Neurologic Long-Term-Care Facilities.

    PubMed

    Couderc, Clotilde; Thiébaut, Anne C M; Lawrence, Christine; Bouchiat, Coralie; Herrmann, Jean-Louis; Salomon, Jérôme; Guillemot, Didier

    2015-12-01

    Staphylococcus aureus nasal carriage is a risk factor for subsequent infection. Estimates of colonization duration vary widely among studies, and factors influencing the time to loss of colonization, especially the impact of antibiotics, remain unclear. We conducted a prospective study on patients naive for S. aureus colonization in 4 French long-term-care facilities. Data on nasal colonization status and potential factors for loss of colonization were collected weekly. We estimated methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) colonization durations using the Kaplan-Meier method and investigated factors for loss of colonization using shared-frailty Cox proportional hazards models. A total of 285 S. aureus colonization episodes were identified in 149 patients. The median time to loss of MRSA or MSSA colonization was 3 weeks (95% confidence interval, 2 to 8 weeks) or 2 weeks (95% confidence interval, 2 to 3 weeks), respectively. In multivariable analyses, the methicillin resistance phenotype was not associated with S. aureus colonization duration (P = 0.21); the use of fluoroquinolones (hazard ratio, 3.37; 95% confidence interval, 1.31 to 8.71) and having a wound positive for a nonnasal strain (hazard ratio, 2.17; 95% confidence interval, 1.15 to 4.07) were associated with earlier loss of MSSA colonization, while no factor was associated with loss of MRSA colonization. These results suggest that the methicillin resistance phenotype does not influence the S. aureus colonization duration and that fluoroquinolones are associated with loss of MSSA colonization but not with loss of MRSA colonization. PMID:26416866

  13. Genetic basis of resistance waves among methicillin resistant Staphylococcus aureus isolates recovered from milk and meat products in Egypt.

    PubMed

    Ammar, A M; Attia, A M; Abd El-Hamid, M I; El-Shorbagy, I M; Abd El-Kader, S A

    2016-01-01

    Antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) poses a serious problem for clinicians worldwide. The present study attempted to evaluate the susceptibility patterns of MRSA to various antimicrobials and the prevalence of inducible clindamycin resistance as well as the relevant antibiotic and antiseptic resistance genes among these isolates. Totally, 40 MRSA isolates were recovered from examined milk and meat product samples (18.60%). Multi-drug resistance (MDR) was remarkably observed among 85% of these isolates. There was a good correlation between phenotypic determination of methicillin, amoxicillin/clavulinic acid and tetracycline resistances and PCR detections of mecA, blaZ and tet(K) genes, respectively, but norA gene was not detected in the four ciprofloxacin resistant isolates. Although, 55% of MRSA expressed resistance to benzalkonium chloride (BC), neither qacA/B nor smr gene was detected. Of 20 isolates exhibiting erythromycin- clindamycin discordant resistance pattern, 8 displayed positive double disk diffusion (D-zone) test denoting inducible macrolide-lincosamide-streptogramin B (MLSB) resistance phenotype with the inducibly expressed erm(A) and erm(C) genes in 87.5% of these isolates. Besides, the remaining 12 isolates showed MS phenotype (resistant to macrolides and type B streptogramins only) with a variety of erm(A), mph(C), msr(A) or a combination of these genes including erm(C). Finally, the constitutive MLSB phenotype with the constitutive expression of erm(A), erm(B) and erm(C) genes was comprised in 2 isolates with higher minimum inhibitory concentration (MIC) values for erythromycin (512 and 1024 µg/ml) and clindamycin (16 and 32 µg/ml). These findings suggested the importance of monitoring the evolution of MRSA resistance. PMID:27609468

  14. Regulation of the expression of the β-lactam antibiotic-resistance determinants in methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Blázquez, Blas; Llarrull, Leticia I; Luque-Ortega, Juan R; Alfonso, Carlos; Boggess, Bill; Mobashery, Shahriar

    2014-03-18

    β-Lactam antibiotics have faced obsolescence with the emergence of methicillin-resistant Staphylococcus aureus (MRSA). A complex set of events ensues upon exposure of MRSA to these antibiotics, which culminates in proteolysis of BlaI or MecI, two gene repressors, and results in the induction of resistance. We report studies on the mechanism of binding of these gene repressors to the operator regions by fluorescence anisotropy. Within the range of in vivo concentrations for BlaI and MecI, these proteins interact with their regulatory elements in a reversible manner, as both a monomer and a dimer. PMID:24564530

  15. Molecular epidemiology of clinical and carrier strains of methicillin resistant Staphylococcus aureus (MRSA) in the hospital settings of north India

    PubMed Central

    Dar, Javid A; Thoker, Manzoor A; Khan, Jamal A; Ali, Asif; Khan, Mohammed A; Rizwan, Mohammed; Bhat, Khalid H; Dar, Mohammad J; Ahmed, Niyaz; Ahmad, Shamim

    2006-01-01

    Background The study was conducted between 2000 and 2003 on 750 human subjects, yielding 850 strains of staphylococci from clinical specimens (575), nasal cultures of hospitalized patients (100) and eye & nasal sources of hospital workers (50 & 125 respectively) in order to determine their epidemiology, acquisition and dissemination of resistance genes. Methods Organisms from clinical samples were isolated, cultured and identified as per the standard routine procedures. Susceptibility was measured by the agar diffusion method, as recommended by the Nat ional Committee for Clinical Laboratory Standards (NCCLS). The modified method of Birnboin and Takahashi was used for isolation of plasmids from staphylococci. Pulsed-field gel electrophoresis (PFGE) typing of clinical and carrier Methicillin resistant Staphylococcus aureus (MRSA) strains isolated during our study was performed as described previously. Results It was shown that 35.1% of Staphylococcus aureus and 22.5% of coagulase-negative staphylococcal isolates were resistant to methicillin. Highest percentage of MRSA (35.5%) was found in pus specimens (n = 151). The multiple drug resistance of all MRSA (n = 180) and Methicillin resistant Coagulase-negative Staphylococcus aureus (MRCNS) (n = 76) isolates was detected. In case of both methicillin-resistant as well as methicillin-sensitive Saphylococcal isolates zero resistance was found to vancomycin where as highest resistance was found to penicillin G followed by ampicillin. It was shown that the major reservoir of methicillin resistant staphylococci in hospitals are colonized/infected inpatients and colonized hospital workers, with carriers at risk for developing endogenous infection or transmitting infection to health care workers and patients. The results were confirmed by molecular typing using PFGE by SmaI-digestion. It was shown that the resistant markers G and T got transferred from clinical S. aureus (JS-105) to carrier S. aureus (JN-49) and the

  16. Nasal colonization in children with community acquired methicillin-resistant Staphylococcus aureus

    PubMed Central

    Davoodabadi, Fazlollah; Mobasherizadeh, Sina; Mostafavizadeh, Kamyar; Shojaei, Hasan; Havaei, Seyed Asghar; Koushki, Ali Mehrabi; Moghadasizadeh, Zahra; Meidani, Mohsen; Shirani, Kiana

    2016-01-01

    Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of infections. The changing epidemiology of MRSA became evident in the 1990s when CA-MRSA cases were first reported. Nasal carriage of CA-MRSA is associated with an increased risk for development of infections in various populations. Materials and Methods: Anterior nares culture for the presence of methicillin-susceptible Staphylococcus aureus (MSSA) and MRSA was taken from 345 children attending kindergartens, who didn’t have any known risk factor for MRSA colonization. Also, children demographic variables were recorded. Identification of SA and community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) with standard microbiological test was performed. Finally, the susceptibility of isolated to various antibiotics determined. The data were analyzed with Whonet 5.6 software. Results: Of 345 children, 20 children (5.8%) were colonized with CA-MRSA, 86 children (24.9%) with MSSA and 239 cases (69.3%) didn’t have SA colonization. The highest rate of MSSA and MRSA colonization was obtained at the age of 6 years. The frequency distribution of SA (MSSA and MRSA) colonization prevalence didn’t have any significant differences based on age, gender and the admission time (P > 0.05); but it was significantly different in the urban areas (P < 0.001). The lowest resistance rate of CA-MRSA isolates, with a frequency of 10%, was detected with gentamicin, rifampin, and trimethoprim-sulfamethoxazole. Conclusions: In summary, CA-MRSA colonization was observed in child care centers remarkably. Therefore, by facing various infections due to SA especially in areas of low socio-economic status, it must be considered. Based on antibiogram test, empirical treatment with rifampin, gentamicin and ciprofloxacin is recommended during CA-MRSA infections. PMID:27274501

  17. Characterization of mannitol-fermenting methicillin-resistant staphylococci isolated from pigs in Nigeria

    PubMed Central

    Ugwu, Clifford C.; Gomez-Sanz, Elena; Agbo, Ifeoma C.; Torres, Carmen; Chah, Kennedy F.

    2015-01-01

    This study was conducted to determine the species distribution, antimicrobial resistance pheno- and genotypes and virulence traits of mannitol-positive methicillin-resistant staphylococci (MRS) isolated from pigs in Nsukka agricultural zone, Nigeria. Twenty mannitol-positive methicillin-resistant coagulase-negative staphylococcal (MRCoNS) strains harboring the mecA gene were detected among the 64 Staphylococcus isolates from 291 pigs. A total of 4 species were identified among the MRCoNS isolates, namely, Staphylococcus sciuri (10 strains), Staphylococcus lentus (6 strains), Staphylococcus cohnii (3 strains) and Staphylococcus haemolyticus (one strain). All MRCoNS isolates were multidrug-resistant. In addition to β-lactams, the strains were resistant to fusidic acid (85%), tetracycline (75%), streptomycin (65%), ciprofloxacin (65%), and trimethoprim/sulphamethoxazole (60%). In addition to the mecA and blaZ genes, other antimicrobial resistance genes detected were tet(K), tet(M), tet(L), erm(B), erm(C), aacA-aphD, aphA3, str, dfrK, dfrG, cat pC221, and cat pC223. Thirteen isolates were found to be ciprofloxacin-resistant, and all harbored a Ser84Leu mutation within the QRDR of the GyrA protein, with 3 isolates showing 2 extra substitutions, Ser98Ile and Arg100Lys (one strain) and Glu88Asp and Asp96Thr (2 strains). A phylogenetic tree of the QRDR nucleotide sequences in the gyrA gene revealed a high nucleotide diversity, with several major clusters not associated with the bacterial species. Our study highlights the possibility of transfer of mecA and other antimicrobial resistance genes from MRCoNS to pathogenic bacteria, which is a serious public health and veterinary concern. PMID:26413075

  18. Characterization of mannitol-fermenting methicillin-resistant staphylococci isolated from pigs in Nigeria.

    PubMed

    Ugwu, Clifford C; Gomez-Sanz, Elena; Agbo, Ifeoma C; Torres, Carmen; Chah, Kennedy F

    2015-01-01

    This study was conducted to determine the species distribution, antimicrobial resistance pheno- and genotypes and virulence traits of mannitol-positive methicillin-resistant staphylococci (MRS) isolated from pigs in Nsukka agricultural zone, Nigeria. Twenty mannitol-positive methicillin-resistant coagulase-negative staphylococcal (MRCoNS) strains harboring the mecA gene were detected among the 64 Staphylococcus isolates from 291 pigs. A total of 4 species were identified among the MRCoNS isolates, namely, Staphylococcus sciuri (10 strains), Staphylococcus lentus (6 strains), Staphylococcus cohnii (3 strains) and Staphylococcus haemolyticus (one strain). All MRCoNS isolates were multidrug-resistant. In addition to β-lactams, the strains were resistant to fusidic acid (85%), tetracycline (75%), streptomycin (65%), ciprofloxacin (65%), and trimethoprim/sulphamethoxazole (60%). In addition to the mecA and blaZ genes, other antimicrobial resistance genes detected were tet(K), tet(M), tet(L), erm(B), erm(C), aacA-aphD, aphA3, str, dfrK, dfrG, cat pC221, and cat pC223. Thirteen isolates were found to be ciprofloxacin-resistant, and all harbored a Ser84Leu mutation within the QRDR of the GyrA protein, with 3 isolates showing 2 extra substitutions, Ser98Ile and Arg100Lys (one strain) and Glu88Asp and Asp96Thr (2 strains). A phylogenetic tree of the QRDR nucleotide sequences in the gyrA gene revealed a high nucleotide diversity, with several major clusters not associated with the bacterial species. Our study highlights the possibility of transfer of mecA and other antimicrobial resistance genes from MRCoNS to pathogenic bacteria, which is a serious public health and veterinary concern.

  19. Recurrent Methicillin-Resistant Staphylococcus aureus Cutaneous Abscesses and Selection of Reduced Chlorhexidine Susceptibility during Chlorhexidine Use.

    PubMed

    Johnson, Ryan C; Schlett, Carey D; Crawford, Katrina; Lanier, Jeffrey B; Merrell, D Scott; Ellis, Michael W

    2015-11-01

    We describe the selection of reduced chlorhexidine susceptibility during chlorhexidine use in a patient with two episodes of cutaneous USA300 methicillin-resistant Staphylococcus aureus abscess. The second clinical isolate harbors a novel plasmid that encodes the QacA efflux pump. Greater use of chlorhexidine for disease prevention warrants surveillance for resistance.

  20. Vulvar Abscess Caused by Methicillin-resistant Staphylococcus Aureus (MRSA) in a Postmenopausal Woman

    PubMed Central

    Kim, Tae-Hee; Kim, Soo Ah; Heo, Gyeong-Eun

    2016-01-01

    Infections of the vulva can present a complex differential to the gynecologist, ranging from superficial skin infections to lifethreatening necrotizing fasciitis. Recognition and timely treatment remain universal to skin and soft-tissue infections as the subcutaneous anatomy of the vulva can facilitate rapid spread to other tissues with significant morbidity and mortality. Employing a multidisciplinary team approach to care for vulvar cellulitis and abscess can guide treatment from antibiotic therapies to more aggressive surgical debridement. In this report, we describe a case of vulvar abscess caused by Methicillin-resistant staphylococcus aureus (MRSA) in a postmenopausal woman with underlying diseases of bronchiectasis and atelectasis. PMID:27617247

  1. A study of community-associated methicillin-resistant Staphylococcus aureus in patients with pyoderma

    PubMed Central

    Venniyil, Prasanth V.; Ganguly, Satyaki; Kuruvila, Sheela; Devi, Sheela

    2016-01-01

    Background: Health care–associated methicillin-resistant Staphylococcus aureus(HA-MRSA) are resistant to multiple antibiotics, therefore infections caused by them are difficult to treat resulting in high morbidity and mortality. While most of the research activities and public health initiatives are focused on HA-MRSA, the newly emerging pathogen, community-associated methicillin-resistant Staphylococcus aureus(CA-MRSA) is gaining in significance in respect to patient morbidity. There is a significant paucity of data regarding CA-MRSA in the developing parts of the world. Aim: To study the proportions of HA-MRSA and CA-MRSA infections among patients with culture-proven S. aureus infection and to find out how many of these patients showed presence of MRSA in nasal cultures of healthy contacts. Materials and Methods: Clinical details of 227 patients were recorded in the study, such as the duration and recurrence of the infection, history of antibiotic intake, and the presence of other medical illnesses. A pus swab was taken from each lesion and sent for culture and sensitivity. If the culture grew S. aureus, they were screened for methicillin resistance. A swab from the anterior nares of the healthy contact of each patient, whenever available, was collected and it was screened for MRSA. Results: Furunculosis was most common among the primary pyodermas (53/134; 39. 5%). Out of 239 pus culture samples obtained from 227 patients, 192 (84.58%) grew S. aureus; of these 150 (78.12%) were methicillin-sensitive S. aureus (MSSA), whereas 42 (21.98%) were MRSA. Out of the 42 MRSA isolated, 33 turned out to be CA-MRSA (78%) and 9 (22%) were HA-MRSA. Nasal swabs of healthy contacts of 34 MRSA patients were cultured. Out of them, two grew MRSA in the culture. Conclusion: The isolation rate of S. aureus was high in our study. Furthermore, our study, although hospital based, clearly indicated the substantial magnitude of the CA-MRSA problem in the local population. PMID:27294048

  2. A case of cavernous sinus thrombosis with meningitis caused by community acquired methicillin resistant Staphylococcus aureus.

    PubMed

    Dinaker, Manjunath; Sharabu, Chandrahasa; Kattula, Sri Rama Surya Tez; Kommalapati, Varun

    2014-05-01

    Septic cavernous sinus thrombosis is a rare clinical condition. Although Staphylococcus aureus is the most common pathogen causing septic cavernous sinus thrombosis [CST], it is an uncommon cause of meningitis. We report the first case of CST with meningitis in Hyderabad, Andhra Pradesh, caused by community acquired epidemic strain of Methicillin resistant staphylococcus aureus [MRSA], in a previously healthy individual with no risk factors. The patient recovered completely following treatment with Vancomycin. We consecutively reviewed all cases of community acquired staphylococcus aureus [CA-MRSA] with central nervous system involvement available in literature. PMID:25508014

  3. A case of cavernous sinus thrombosis with meningitis caused by community acquired methicillin resistant Staphylococcus aureus.

    PubMed

    Dinaker, Manjunath; Sharabu, Chandrahasa; Kattula, Sri Rama Surya Tez; Kommalapati, Varun

    2014-05-01

    Septic cavernous sinus thrombosis is a rare clinical condition. Although Staphylococcus aureus is the most common pathogen causing septic cavernous sinus thrombosis [CST], it is an uncommon cause of meningitis. We report the first case of CST with meningitis in Hyderabad, Andhra Pradesh, caused by community acquired epidemic strain of Methicillin resistant staphylococcus aureus [MRSA], in a previously healthy individual with no risk factors. The patient recovered completely following treatment with Vancomycin. We consecutively reviewed all cases of community acquired staphylococcus aureus [CA-MRSA] with central nervous system involvement available in literature. PMID:25438497

  4. Comparison of four genotyping assays for epidemiological study of methicillin-resistant Staphylococcus aureus.

    PubMed

    van Belkum, A; Bax, R; Prevost, G

    1994-05-01

    Twenty-six methicillin-resistant Staphylococcus aureus strains were genetically differentiated by interrepeat PCR and the results compared with those of ribotyping, pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA analysis obtained in a previous study for the same strains. The comparison showed that the PCR-mediated assays were as discriminatory as PFGE, whereas ribotyping was the least powerful genotyping method. Due to the ease of performance, PCR fingerprinting may become the method of choice for establishing clonal relationship among Staphylococcus aureus isolates.

  5. Vulvar Abscess Caused by Methicillin-resistant Staphylococcus Aureus (MRSA) in a Postmenopausal Woman

    PubMed Central

    Kim, Tae-Hee; Kim, Soo Ah; Heo, Gyeong-Eun

    2016-01-01

    Infections of the vulva can present a complex differential to the gynecologist, ranging from superficial skin infections to lifethreatening necrotizing fasciitis. Recognition and timely treatment remain universal to skin and soft-tissue infections as the subcutaneous anatomy of the vulva can facilitate rapid spread to other tissues with significant morbidity and mortality. Employing a multidisciplinary team approach to care for vulvar cellulitis and abscess can guide treatment from antibiotic therapies to more aggressive surgical debridement. In this report, we describe a case of vulvar abscess caused by Methicillin-resistant staphylococcus aureus (MRSA) in a postmenopausal woman with underlying diseases of bronchiectasis and atelectasis.

  6. Benzimidazole analogs as WTA biosynthesis inhibitors targeting methicillin resistant Staphylococcus aureus.

    PubMed

    Yang, Shu-Wei; Pan, Jianping; Yang, Christine; Labroli, Marc; Pan, Weidong; Caldwell, John; Ha, Sookhee; Koseoglu, Sandra; Xiao, Jing C; Mayhood, Todd; Sheth, Payal R; Garlisi, Charles G; Wu, Jin; Lee, Sang Ho; Wang, Hao; Tan, Christopher M; Roemer, Terry; Su, Jing

    2016-10-01

    A series of benzimidazole analogs have been synthesized to improve the profile of the previous lead compounds tarocin B and 1. The syntheses, structure-activity relationships, and selected biochemical data of these analogs are described. The optimization efforts allowed the identification of 21, a fluoro-substituted benzimidazole, exhibiting potent TarO inhibitory activity and typical profile for a wall teichoic acid (WTA) biosynthesis inhibitor. Compound 21 displayed a potent synergistic and bactericidal effect in combination with imipenem against diverse methicillin-resistant Staphylococci. PMID:27575474

  7. Colonic Perforation Caused by Methicillin-Resistant Staphylococcus aureus Enteritis After Total Gastrectomy: A Case Report.

    PubMed

    Furukawa, Kenei; Tsutsumi, Jun; Takayama, Sumio; Mashiko, Hiroshi; Shiba, Hiroaki; Yanaga, Katsuhiko

    2015-03-01

    A 68-year-old man underwent total gastrectomy and splenectomy for adenocarcinoma and low anterior resection for carcinoma in tubulo-villous adenoma of the rectum. Broad-spectrum antibiotics were administered for postoperative pancreatic fistula. Methicillin-resistant Staphylococcus aureus enteritis occurred on the 50th postoperative day and cecal perforation followed. The patient underwent construction of cecostomy with peritoneal drainage, and vancomycin was administered orally and per cecostomy for 2 weeks. The patient recovered well and was discharged at 35 days after re-operation in good general condition.

  8. Identification of a methicillin-resistant Staphylococcus aureus inhibitory compound isolated from Serratia marcescens

    PubMed Central

    Kadouri, Daniel E.; Shanks, Robert M.Q.

    2013-01-01

    In this study, we identified an antimicrobial compound produced by the Gram-negative bacterium Serratia marcescens. Colonies of S. marcescens inhibited the growth of nine different methicillin-resistant Staphylococcus aureus (MRSA) isolates and several other tested Gram-positive bacterial species, but not Gram-negative bacteria. Genetic analysis revealed the requirement for the swrW gene which codes for a non-ribosomal peptide synthetase that generates the cyclodepsipeptide antibiotic serratamolide, also known as serrawettin W1. This is the first report describing the anti-MRSA properties of serratamolide. PMID:23791620

  9. Vulvar Abscess Caused by Methicillin-resistant Staphylococcus Aureus (MRSA) in a Postmenopausal Woman.

    PubMed

    Kim, Tae-Hee; Seap, Bel; Kim, Soo Ah; Heo, Gyeong-Eun

    2016-08-01

    Infections of the vulva can present a complex differential to the gynecologist, ranging from superficial skin infections to lifethreatening necrotizing fasciitis. Recognition and timely treatment remain universal to skin and soft-tissue infections as the subcutaneous anatomy of the vulva can facilitate rapid spread to other tissues with significant morbidity and mortality. Employing a multidisciplinary team approach to care for vulvar cellulitis and abscess can guide treatment from antibiotic therapies to more aggressive surgical debridement. In this report, we describe a case of vulvar abscess caused by Methicillin-resistant staphylococcus aureus (MRSA) in a postmenopausal woman with underlying diseases of bronchiectasis and atelectasis. PMID:27617247

  10. Cultivation of vancomycin-resistant enterococci and methicillin-resistant staphylococci from input and output samples of German biogas plants.

    PubMed

    Glaeser, Stefanie P; Sowinsky, Olivia; Brunner, Jana S; Dott, Wolfgang; Kämpfer, Peter

    2016-03-01

    Vancomycin-resistant enterococci (VRE) and methicillin-resistant staphylococci (MRS) were detected in two mesophilic German biogas plants (BGPs) using selective pre-enrichment methods combined with cultivation on CHROMagar media and antibiotic resistance gene screening. Genetic fingerprinting and 16S rRNA gene sequencing showed the presence of enterococci isolated by the VRE selective cultivation (67 isolates) in input and output samples of BGPs. In contrast, MRS (44 isolates) were detected in input, but in none of the output samples. Enterococcus isolates showed highest 16S rRNA gene sequence similarity (>99.8%) to E. lemanii, E. casseliflavus/E. gallinarium or E. devriesei/E. pseudoavium/E. viikkiensis and carried vanA, vanB and/or vanC1 genes. Enterococcus faecium and E. faecalis VRE were not detected, but isolates closely related to those species (>99.9% 16S rRNA gene sequence similarity) were detected by the MRS selective cultivation methods. Staphylococcus isolates shared highest 16S rRNA gene sequence similarity (>99.9%) with S. haemolyticus, S. lentus and S. sciuri and carried mecA genes. Methicillin-resistant S. aureus (MRSA) were not detected. In summary, manure from livestock husbandry contained both, VRE and MRS. VRE were also detected in output samples, indicating that enterococci with vancomycin resistance genes could be release into the environment by the application of BGP output material as biofertilizers.

  11. The changing face of community-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Kale, P; Dhawan, B

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of infection, both in hospitalised patients with significant healthcare exposure and in patients without healthcare risk factors. Community-acquired methicillin-resistant S. aureus (CA-MRSA) are known for their rapid community transmission and propensity to cause aggressive skin and soft tissue infections and community-acquired pneumonia. The distinction between the healthcare-associated (HA)-MRSA and CA-MRSA is gradually fading owing to the acquisition of multiple virulence factors and genetic elements. The movement of CA-MRSA strains into the nosocomial setting limits the utility of using clinical risk factors alone to designate community or HA status. Identification of unique genetic characteristics and genotyping are valuable tools for MRSA epidemiological studies. Although the optimum pharmacotherapy for CA-MRSA infections has not been determined, many CA-MRSA strains remain broadly susceptible to several non-β-lactam antibacterial agents. This review aimed at illuminating the characteristic features of CA-MRSA, virulence factors, changing clinical settings and molecular epidemiology, insurgence into the hospital settings and therapy with drug resistance. PMID:27514947

  12. The Pleiotropic Antibacterial Mechanisms of Ursolic Acid against Methicillin-Resistant Staphylococcus aureus (MRSA).

    PubMed

    Wang, Chao-Min; Jhan, Yun-Lian; Tsai, Shang-Jie; Chou, Chang-Hung

    2016-07-07

    (1) BACKGROUND: Several triterpenoids were found to act synergistically with classes of antibiotic, indicating that plant-derived chemicals have potential to be used as therapeutics to enhance the activity of antibiotics against multidrug-resistant pathogens. However, the mode of action of triterpenoids against bacterial pathogens remains unclear. The objective of this study is to evaluate the interaction between ursolic acid against methicillin-resistant Staphylococcus aureus (MRSA); (2) METHODS: The ability of ursolic acid to damage mammalian and bacterial membranes was examined. The proteomic response of methicillin-resistant S. aureus in ursolic acid treatment was investigated using two-dimensional (2D) proteomic analysis; (3) RESULTS: Ursolic acid caused the loss of staphylococcal membrane integrity without hemolytic activity. The comparison of the protein pattern of ursolic acid-treated and normal MRSA cells revealed that ursolic acid affected a variety of proteins involved in the translation process with translational accuracy, ribonuclease and chaperon subunits, glycolysis and oxidative responses; (4) CONCLUSION: The mode of action of ursolic acid appears to be the influence on the integrity of the bacterial membrane initially, followed by inhibition of protein synthesis and the metabolic pathway. These findings reflect that the pleiotropic effects of ursolic acid against MRSA make it a promising antibacterial agent in pharmaceutical research.

  13. The Pleiotropic Antibacterial Mechanisms of Ursolic Acid against Methicillin-Resistant Staphylococcus aureus (MRSA).

    PubMed

    Wang, Chao-Min; Jhan, Yun-Lian; Tsai, Shang-Jie; Chou, Chang-Hung

    2016-01-01

    (1) BACKGROUND: Several triterpenoids were found to act synergistically with classes of antibiotic, indicating that plant-derived chemicals have potential to be used as therapeutics to enhance the activity of antibiotics against multidrug-resistant pathogens. However, the mode of action of triterpenoids against bacterial pathogens remains unclear. The objective of this study is to evaluate the interaction between ursolic acid against methicillin-resistant Staphylococcus aureus (MRSA); (2) METHODS: The ability of ursolic acid to damage mammalian and bacterial membranes was examined. The proteomic response of methicillin-resistant S. aureus in ursolic acid treatment was investigated using two-dimensional (2D) proteomic analysis; (3) RESULTS: Ursolic acid caused the loss of staphylococcal membrane integrity without hemolytic activity. The comparison of the protein pattern of ursolic acid-treated and normal MRSA cells revealed that ursolic acid affected a variety of proteins involved in the translation process with translational accuracy, ribonuclease and chaperon subunits, glycolysis and oxidative responses; (4) CONCLUSION: The mode of action of ursolic acid appears to be the influence on the integrity of the bacterial membrane initially, followed by inhibition of protein synthesis and the metabolic pathway. These findings reflect that the pleiotropic effects of ursolic acid against MRSA make it a promising antibacterial agent in pharmaceutical research. PMID:27399657

  14. The changing face of community-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Kale, P; Dhawan, B

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of infection, both in hospitalised patients with significant healthcare exposure and in patients without healthcare risk factors. Community-acquired methicillin-resistant S. aureus (CA-MRSA) are known for their rapid community transmission and propensity to cause aggressive skin and soft tissue infections and community-acquired pneumonia. The distinction between the healthcare-associated (HA)-MRSA and CA-MRSA is gradually fading owing to the acquisition of multiple virulence factors and genetic elements. The movement of CA-MRSA strains into the nosocomial setting limits the utility of using clinical risk factors alone to designate community or HA status. Identification of unique genetic characteristics and genotyping are valuable tools for MRSA epidemiological studies. Although the optimum pharmacotherapy for CA-MRSA infections has not been determined, many CA-MRSA strains remain broadly susceptible to several non-β-lactam antibacterial agents. This review aimed at illuminating the characteristic features of CA-MRSA, virulence factors, changing clinical settings and molecular epidemiology, insurgence into the hospital settings and therapy with drug resistance.

  15. Optimizing testing of methicillin-resistant Staphylococcus species.

    PubMed

    Baker, C N; Huang, M B; Tenover, F C

    1994-07-01

    Selection of the appropriate NaCl concentration for test medium for oxacillin susceptibility testing of Staphylococcus aureus and coagulase-negative staphylococci has been problematic when using different antimicrobial susceptibility testing methods. Broth microdilution, using cation-adjusted Mueller-Hinton broth + 2% NaCl, is the currently recommended reference method. There is currently no recommendation for the addition of NaCl to agar for dilution susceptibility tests when Staphylococcus species are tested with oxacillin. We examined the effects of adding 0, 2%, 4%, and 5% NaCl to Mueller-Hinton agar and broth for agar dilution, Etest, and broth microdilution tests. The results of these tests were compared with the reference broth microdilution results and with the results of a hybridization assay using a mec gene probe. We tested 223 strains of staphylococci, 128 of which were mec gene positive and had oxacillin minimum inhibitory concentrations (MICs) > or = 4 micrograms/ml. Seven strains of S. aureus were mec probe negative but were oxacillin resistant. Seven coagulase-negative strains (three S. epidermidis, one S. haemolyticus, and three S. simulans) were mec probe positive and were oxacillin susceptible. The MICs for oxacillin-resistant strains increased two- to fourfold with the addition of 2% NaCl, but the MICs for oxacillin-susceptible strains were unchanged. Major and very major interpretative rates ranged from 18.2% to 20.2% for agar dilution and Etest without NaCl added to the medium, and these rates decreased to < 1% with the addition of 2% NaCl to the medium. The addition of 4% or 5% NaCl caused major error rates of > 17% for all test methods.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Optimizing testing of methicillin-resistant Staphylococcus species.

    PubMed

    Baker, C N; Huang, M B; Tenover, F C

    1994-07-01

    Selection of the appropriate NaCl concentration for test medium for oxacillin susceptibility testing of Staphylococcus aureus and coagulase-negative staphylococci has been problematic when using different antimicrobial susceptibility testing methods. Broth microdilution, using cation-adjusted Mueller-Hinton broth + 2% NaCl, is the currently recommended reference method. There is currently no recommendation for the addition of NaCl to agar for dilution susceptibility tests when Staphylococcus species are tested with oxacillin. We examined the effects of adding 0, 2%, 4%, and 5% NaCl to Mueller-Hinton agar and broth for agar dilution, Etest, and broth microdilution tests. The results of these tests were compared with the reference broth microdilution results and with the results of a hybridization assay using a mec gene probe. We tested 223 strains of staphylococci, 128 of which were mec gene positive and had oxacillin minimum inhibitory concentrations (MICs) > or = 4 micrograms/ml. Seven strains of S. aureus were mec probe negative but were oxacillin resistant. Seven coagulase-negative strains (three S. epidermidis, one S. haemolyticus, and three S. simulans) were mec probe positive and were oxacillin susceptible. The MICs for oxacillin-resistant strains increased two- to fourfold with the addition of 2% NaCl, but the MICs for oxacillin-susceptible strains were unchanged. Major and very major interpretative rates ranged from 18.2% to 20.2% for agar dilution and Etest without NaCl added to the medium, and these rates decreased to < 1% with the addition of 2% NaCl to the medium. The addition of 4% or 5% NaCl caused major error rates of > 17% for all test methods.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7820997

  17. Application of the SCCmec element in the molecular typing of methicillin-resistant Staphylococcus aureus.

    PubMed

    Yancheng, Yang; Hang, Cheng; Renjie, Zhou; Xiancai, Rao

    2015-05-01

    Acquisition of the staphylococcal chromosome cassette mec (SCCmec) is one of the key reasons for the resistance of methicillin-resistant Staphylococcus aureus (MRSA). SCCmec is composed of a mec gene complex encoding the PBP2a determinant that is responsible for the β-lactam resistance of MRSA, and a ccr gene complex encoding recombinases that mediate the integration of SCCmec into and its excision from the recipient chromosome, and so-called three junkyard (J) regions of different sizes. The SCCmec elements carried by MRSA from different geographic locations are diverse, and each type contains characteristic DNA fragments in size. These characteristics of SCCmec element may facilitate the usage of SCCmec in the molecular typing of MRSA strains. In this review, we summarize the structure and function of SCCmec elecments, and discuss the application of SCCmec elements in the molecular typing of MRSA.

  18. Sentinel cases of community-acquired methicillin-resistant Staphylococcus aureus onboard a naval ship.

    PubMed

    LaMar, James E; Carr, Russell B; Zinderman, Craig; McDonald, Kimberly

    2003-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is emerging as a community-acquired organism. A number of recent reports have documented its involvement in a variety of infections in which no risk factors for nosocomial transmission are present. This report presents the initial cases of a MRSA outbreak on a U.S. Navy ship. Each patient failed traditional antibiotic therapy and one required hospitalization. Their presentations evolved simultaneously and proved to be sentinel cases of an outbreak of cutaneous MRSA infections. The events of this outbreak emphasize the growing need to consider the prevalence of resistant organisms in outpatient settings, as well as the impact that infections from resistant organisms might have on the combat readiness of a military unit. Recommendations addressing infection-control guidelines for MRSA within close-quarter environments of healthy adults, such as military units, need to be developed and existing infection-control measures need to be regularly emphasized.

  19. In vitro and in vivo activities of a novel cephalosporin, BMS-247243, against methicillin-resistant and -susceptible staphylococci.

    PubMed

    Fung-Tomc, Joan C; Clark, Junius; Minassian, Beatrice; Pucci, Michael; Tsai, Yuan-Hwang; Gradelski, Elizabeth; Lamb, Lucinda; Medina, Ivette; Huczko, Elizabeth; Kolek, Benjamin; Chaniewski, Susan; Ferraro, Cheryl; Washo, Thomas; Bonner, Daniel P

    2002-04-01

    The recent emergence of methicillin-resistant Staphylococcus aureus (MRSA) with decreased susceptibility to vancomycin has intensified the search for alternative therapies for the treatment of infections caused by this organism. One approach has been to identify a beta-lactam with improved affinity for PBP 2a, the target enzyme responsible for methicillin resistance in staphylococci. BMS-247243 is such a candidate, with MICs that inhibit 90% of isolates tested (MIC(90)s) of 4, 2, and 8 microg/ml for methicillin-resistant strains of S. aureus, S. epidermidis, and S. haemolyticus, respectively, as determined on plates with Mueller-Hinton agar and 2% NaCl. The BMS-247243 MICs for MRSA were minimally affected by the susceptibility testing conditions (inoculum size, prolonged incubation, addition of salt to the test medium) or by staphylococcal beta-lactamases. BMS-247243 MIC(90)s for methicillin-susceptible staphylococcal species ranged from < or = 0.25 to 1 microg/ml. The BMS-247243 MIC(90) for beta-lactamase-producing S. aureus strains was fourfold higher than that for beta-lactamase-nonproducing strains. BMS-247243 is hydrolyzed by staphylococcal beta-lactamases at 4.5 to 26.2% of the rates measured for cephaloridine. The affinity of BMS-247243 for PBP 2a was >100-fold better than that of methicillin or cefotaxime. BMS-247243 is bactericidal for MRSA, killing the bacteria twice as fast as vancomycin. These in vitro activities of BMS-247243 correlated with its in vivo efficacy against infections in animals, including the neutropenic murine thigh and rabbit endocarditis models involving MRSA strains. In conclusion, BMS-247243 has in vitro and in vivo activities against methicillin-resistant staphylococci and thus may prove to be useful in the treatment of infections caused by these multidrug-resistant organisms.

  20. In vitro and in vivo activities of a novel cephalosporin, BMS-247243, against methicillin-resistant and -susceptible staphylococci.

    PubMed

    Fung-Tomc, Joan C; Clark, Junius; Minassian, Beatrice; Pucci, Michael; Tsai, Yuan-Hwang; Gradelski, Elizabeth; Lamb, Lucinda; Medina, Ivette; Huczko, Elizabeth; Kolek, Benjamin; Chaniewski, Susan; Ferraro, Cheryl; Washo, Thomas; Bonner, Daniel P

    2002-04-01

    The recent emergence of methicillin-resistant Staphylococcus aureus (MRSA) with decreased susceptibility to vancomycin has intensified the search for alternative therapies for the treatment of infections caused by this organism. One approach has been to identify a beta-lactam with improved affinity for PBP 2a, the target enzyme responsible for methicillin resistance in staphylococci. BMS-247243 is such a candidate, with MICs that inhibit 90% of isolates tested (MIC(90)s) of 4, 2, and 8 microg/ml for methicillin-resistant strains of S. aureus, S. epidermidis, and S. haemolyticus, respectively, as determined on plates with Mueller-Hinton agar and 2% NaCl. The BMS-247243 MICs for MRSA were minimally affected by the susceptibility testing conditions (inoculum size, prolonged incubation, addition of salt to the test medium) or by staphylococcal beta-lactamases. BMS-247243 MIC(90)s for methicillin-susceptible staphylococcal species ranged from < or = 0.25 to 1 microg/ml. The BMS-247243 MIC(90) for beta-lactamase-producing S. aureus strains was fourfold higher than that for beta-lactamase-nonproducing strains. BMS-247243 is hydrolyzed by staphylococcal beta-lactamases at 4.5 to 26.2% of the rates measured for cephaloridine. The affinity of BMS-247243 for PBP 2a was >100-fold better than that of methicillin or cefotaxime. BMS-247243 is bactericidal for MRSA, killing the bacteria twice as fast as vancomycin. These in vitro activities of BMS-247243 correlated with its in vivo efficacy against infections in animals, including the neutropenic murine thigh and rabbit endocarditis models involving MRSA strains. In conclusion, BMS-247243 has in vitro and in vivo activities against methicillin-resistant staphylococci and thus may prove to be useful in the treatment of infections caused by these multidrug-resistant organisms. PMID:11897577

  1. Antibacterial activity of THAM Trisphenylguanide against methicillin-resistant Staphylococcus aureus.

    PubMed

    Weaver, Alan J; Shepard, Joyce B; Wilkinson, Royce A; Watkins, Robert L; Walton, Sarah K; Radke, Amanda R; Wright, Thomas J; Awel, Milat B; Cooper, Catherine; Erikson, Elizabeth; Labib, Mohamed E; Voyich, Jovanka M; Teintze, Martin

    2014-01-01

    This study investigated the potential antibacterial activity of three series of compounds synthesized from 12 linear and branched polyamines with 2-8 amino groups, which were substituted to produce the corresponding guanides, biguanides, or phenylguanides, against Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Antibacterial activity was measured for each compound by determining the minimum inhibitory concentration against the bacteria, and the toxicity towards mammalian cells was determined. The most effective compound, THAM trisphenylguanide, was studied in time-to-kill and cytoplasmic leakage assays against methicillin-resistant Staphylococcus aureus (MRSA, USA300) in comparison to chlorhexidine. Preliminary toxicity and MRSA challenge studies in mice were also conducted on this compound. THAM trisphenylguanide showed significant antibacterial activity (MIC ∼1 mg/L) and selectivity against MRSA relative to all the other bacteria examined. In time-to-kill assays it showed increased antimicrobial activity against MRSA versus chlorhexidine. It induced leakage of cytoplasmic content at concentrations that did not reduce cell viability, suggesting the mechanism of action may involve membrane disruption. Using an intraperitoneal mouse model of invasive MRSA disease, THAM trisphenylguanide reduced bacterial burden locally and in deeper tissues. This study has identified a novel guanide compound with selective microbicidal activity against Staphylococcus aureus, including a methicillin-resistant (MRSA) strain.

  2. Patients with Methicillin-Resistant Staphylococcus aureus (MRSA) Infection – 21st Century Lepers

    PubMed Central

    Mozzillo, Kristin L.; Ortiz, Nancy; Miller, Loren G.

    2009-01-01

    In the recent past, there has been a dramatic increase in the incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections, especially community-associated methicillin-resistant S. aureus (CA-MRSA) infections. Many media descriptions of MRSA are sensational and focus on its potential for severe disease and contagiousness. Our objective is to describe psychological and social morbidity associated with MRSA infection via a case series of five patients with CA-MRSA infection. We also analyze the resulting stigmatization associated with being diagnosed with MRSA infection. We learned that patients describe a variety of stigmatization related to their diagnosis of MRSA, including being shunned at home and in the workplace. Patients describe being asked by family, colleagues, and clients to take extraordinary measures to prevent MRSA transmission. Consequences of MRSA diagnoses have included erosion or termination of key personal and business relationships. In conclusion, stigmatization resulting from the diagnosis of MRSA can have profound personal and social morbidity. Media and public health awareness of MRSA infection needs to be balanced with information about how MRSA transmission is usually preventable with simple hygienic measures. PMID:20236730

  3. Ultrastructural changes in methicillin-resistant Staphylococcus aureus induced by positively charged silver nanoparticles

    PubMed Central

    Romero-Urbina, Dulce G; Lara, Humberto H; Velázquez-Salazar, J Jesús; Arellano-Jiménez, M Josefina; Larios, Eduardo; Srinivasan, Anand; Lopez-Ribot, Jose L

    2015-01-01

    Summary Silver nanoparticles offer a possible means of fighting antibacterial resistance. Most of their antibacterial properties are attributed to their silver ions. In the present work, we study the actions of positively charged silver nanoparticles against both methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus. We use aberration-corrected transmission electron microscopy to examine the bactericidal effects of silver nanoparticles and the ultrastructural changes in bacteria that are induced by silver nanoparticles. The study revealed that our 1 nm average size silver nanoparticles induced thinning and permeabilization of the cell wall, destabilization of the peptidoglycan layer, and subsequent leakage of intracellular content, causing bacterial cell lysis. We hypothesize that positively charged silver nanoparticles bind to the negatively charged polyanionic backbones of teichoic acids and the related cell wall glycopolymers of bacteria as a first target, consequently stressing the structure and permeability of the cell wall. This hypothesis provides a major mechanism to explain the antibacterial effects of silver nanoparticles on Staphylococcus aureus. Future research should focus on defining the related molecular mechanisms and their importance to the antimicrobial activity of silver nanoparticles. PMID:26734530

  4. Bactericidal Effects of Charged Silver Nanoparticles in Methicillin-resistant Staphylococcus aureus

    NASA Astrophysics Data System (ADS)

    Romero-Urbina, Dulce; Velazquez-Salazar, J. Jesus; Lara, Humberto H.; Arellano-Jimenez, Josefina; Larios, Eduardo; Yuan, Tony T.; Hwang, Yoon; Desilva, Mauris N.; Jose-Yacaman, Miguel

    2015-03-01

    The increased number of infections due to antibiotic-resistant bacteria is a major concern to society. The objective of this work is to determine the effect of positively charged AgNPs on methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus(MRSA) cell wall using advanced electron microscopy techniques. Positively charged AgNPs suspensions were synthesized via a microwave heating technique. The suspensions were then characterized by Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) showing AgNPs size range from 5 to 30 nm. MSSA and MRSA were treated with positively charged AgNPs concentrations ranging from 0.06 mM to 31 mM. The MIC50 studies showed that viability of MSSA and MRSA could be reduced by 50% at a positively charged AgNPs concentration of 0.12 mM supported by Scanning-TEM (STEM) images demonstrating bacteria cell wall disruption leading to lysis after treatment with AgNPs. The results provide insights into one mechanism in which positively charged AgNPs are able to reduce the viability of MSSA and MRSA. This research is supported by National Institute on Minority Health and Health Disparities (G12MD007591) from NIH, NSF-PREM Grant No. DMR-0934218, The Welch Foundation and NAMRU-SA work number G1009.

  5. Biophysical analysis of the putative acetyltransferase SACOL2570 from methicillin-resistant Staphylococcus aureus

    PubMed Central

    Luo, Hai-Bin; Knapik, Aleksandra A.; Petkowski, Janusz J.; Demas, Matthew; Shumilin, Igor A.; Zheng, Heping; Chruszcz, Maksymilian

    2013-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of a myriad of insidious and intractable infections in humans, especially in patients with compromised immune systems and children. Here, we report the apo- and CoA-bound crystal structures of a member of the galactoside acetyltransferase superfamily from methicillin-resistant S. aureus SACOL2570 which was recently shown to be down regulated in S. aureus grown in the presence of fusidic acid, an antibiotic used to treat MRSA infections. SACOL2570 forms a homotrimerin solution, as confirmed by small-angle X-ray scattering and dynamic light scattering. The protein subunit consists of an N-terminal alpha-helical domain connected to a C-terminal LβH domain. CoA binds in the active site formed by the residues from adjacent LβH domains. After determination of CoA-bound structure, molecular dynamics simulations were performed to model the binding of AcCoA. Binding of both AcCoA and CoA to SACOL2570 was verified by isothermal titration calorimetry. SACOL2570 most likely acts as an acetyltransferase, using AcCoA as an acetyl group donor and an as-yet-undetermined chemical moiety as an acceptor. SACOL2570 was recently used as a scaffold for mutations that lead the generation of cage-like assemblies, and has the potential to be used for the generation of more complex nanostructures. PMID:23963951

  6. Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) at ambient freshwater beaches.

    PubMed

    Fogarty, Lisa R; Haack, Sheridan K; Johnson, Heather E; Brennan, Angela K; Isaacs, Natasha M; Spencer, Chelsea

    2015-09-01

    Methicillin-resistant Staphylococcus aureus (MRSA) are a threat to human health worldwide, and although detected at marine beaches, they have been largely unstudied at freshwater beaches. Genes indicating S. aureus (SA; femA) and methicillin resistance (mecA) were detected at 11 and 12 of 13 US Great Lakes beaches and in 18% or 27% of 287 recreational water samples, respectively. Eight beaches had mecA+femA (potential MRSA) detections. During an intensive study, higher bather numbers, staphylococci concentrations, and femA detections were found in samples collected after noon than before noon. Local population density, beach cloud cover, and beach wave height were significantly correlated with SA or MRSA detection frequency. The Panton-Valentine leukocidin gene, associated with community-acquired MRSA, was detected in 12 out of 27 potential MRSA samples. The femA gene was detected less frequently at beaches that met US enterococci criteria or EU enterococci 'excellent' recreational water quality, but was not related to Escherichia coli-defined criteria. Escherichia coli is often the only indicator used to determine water quality at US beaches, given the economic and healthcare burden that can be associated with infections caused by SA and MRSA, monitoring of recreational waters for non-fecal bacteria such as staphylococci and/or SA may be warranted.

  7. Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) at ambient freshwater beaches

    USGS Publications Warehouse

    Fogarty, Lisa R.; Haack, Sheridan K.; Johnson, Heather E.; Brennan, Angela K.; Isaacs, Natasha M.; Spencer, Chelsea

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) are a threat to human health worldwide, and although detected at marine beaches, they have been largely unstudied at freshwater beaches. Genes indicating S. aureus (SA; femA) and methicillin resistance (mecA) were detected at 11 and 12 of 13 US Great Lakes beaches and in 18% or 27% of 287 recreational water samples, respectively. Eight beaches had mecA + femA (potential MRSA) detections. During an intensive study, higher bather numbers, staphylococci concentrations, and femA detections were found in samples collected after noon than before noon. Local population density, beach cloud cover, and beach wave height were significantly correlated with SA or MRSA detection frequency. The Panton-Valentine leukocidin gene, associated with community-acquired MRSA, was detected in 12 out of 27 potential MRSA samples. The femA gene was detected less frequently at beaches that met US enterococci criteria or EU enterococci ‘excellent’ recreational water quality, but was not related to Escherichia coli-defined criteria. Escherichia coli is often the only indicator used to determine water quality at US beaches, given the economic and healthcare burden that can be associated with infections caused by SA and MRSA, monitoring of recreational waters for non-fecal bacteria such as staphylococci and/or SA may be warranted.

  8. Ultrastructural changes in methicillin-resistant Staphylococcus aureus induced by positively charged silver nanoparticles.

    PubMed

    Romero-Urbina, Dulce G; Lara, Humberto H; Velázquez-Salazar, J Jesús; Arellano-Jiménez, M Josefina; Larios, Eduardo; Srinivasan, Anand; Lopez-Ribot, Jose L; Yacamán, Miguel José

    2015-01-01

    Silver nanoparticles offer a possible means of fighting antibacterial resistance. Most of their antibacterial properties are attributed to their silver ions. In the present work, we study the actions of positively charged silver nanoparticles against both methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus. We use aberration-corrected transmission electron microscopy to examine the bactericidal effects of silver nanoparticles and the ultrastructural changes in bacteria that are induced by silver nanoparticles. The study revealed that our 1 nm average size silver nanoparticles induced thinning and permeabilization of the cell wall, destabilization of the peptidoglycan layer, and subsequent leakage of intracellular content, causing bacterial cell lysis. We hypothesize that positively charged silver nanoparticles bind to the negatively charged polyanionic backbones of teichoic acids and the related cell wall glycopolymers of bacteria as a first target, consequently stressing the structure and permeability of the cell wall. This hypothesis provides a major mechanism to explain the antibacterial effects of silver nanoparticles on Staphylococcus aureus. Future research should focus on defining the related molecular mechanisms and their importance to the antimicrobial activity of silver nanoparticles. PMID:26734530

  9. Comparative phenotypic and genotypic discrimination of methicillin resistant and susceptible Staphylococcus aureus in Egypt.

    PubMed

    Abd El-Hamid, Marwa I; Bendary, M M

    2015-09-26

    The present study was designed to elucidate the phenotypic and genotypic characterization of S. aureus isolates in Egypt. The antibiotic susceptibility pattern of 133 identified S. aureus isolates revealed that over 70% of the isolates were multi-drug resistant (MDR). Fifty MDR isolates were characterized using antibiotyping and different molecular typing methods. Amplification of mecA gene confirmed 30 strains as methicillin-resistant S. aureus (MRSA) and 20 as methicillin-sensitive S. aureus (MSSA). Generally, 22 MRSA (73.33%) and ten MSSA (50%) harbored Panton-Valentine leukocidin (pvl) gene with no statistically significant difference (p=0.093). Staphylococcal cassette chromosome (SCC) mec typing revealed that 48% of the typeable MRSA isolates possessed SCCmec type IV. SCCmec and antimicrobial susceptibility typing signified the presence of community-acquired (CA)-MRSA in Egypt. Surprisingly, all isolates of SCCmec types I, II and III and 50% of both MRSA isolates of SCCmec types IV and V possessed pvl gene. It was clear that staphylococcal protein A (spa) and coagulase (coa) typing discriminated the isolates into eight different groups, whilst polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of coagulase gene yielded ten distinct RFLP banding patterns. This study presented the first baseline information on the characterization of MRSA and MSSA in Egypt.

  10. Community-associated methicillin-resistant Staphylococcus aureus in non-outbreak skin infections

    PubMed Central

    Bonesso, Mariana Fávero; Marques, Silvio Alencar; Camargo, Carlos Henrique; Fortaleza, Carlos Magno Castelo Branco; da Cunha, Maria de Lourdes Ribeiro de Souza

    2014-01-01

    The aim of this study was to determine the prevalence of Staphylococcus aureus and risk factors for the acquisition of MRSA (Methicillin Resistant Staphylococcus aureus) as the main cause of skin and soft tissue infections. S. aureus were characterized for the presence of PVL, TSST-1 and mecA genes. SCCmec typing was carried out in mecA positive strains and PFGE was performed only in these strains. During the study period, 127 outpatients attending a dermatology clinical the Botucatu Medical School, a regional tertiary hospital in Botucatu, Sao Paulo, Brazil, were diagnosed with active skin infections. A total 66 (56.9%) S. aureus strains were isolated. The methicillin resistance gene mecA was detected in seven (10.6%) S. aureus strains. The SCCmec types detected in the seven mecA-positive S. aureus strains were type Ia in one, type II in three, and type IV in three. The PVL gene was detected in 10 (15.1%) in sensitive strains. Pulsed field gel electrophoresis revealed non-clonal diversity among the isolates. The risk factors associated with MRSA acquisition in this study were previous ciprofloxacin use and working in a healthcare environment. The risk factors indicate plausible routes of CA-MRSA transmission among the subjects studied. PMID:25763047

  11. Occurrence of methicillin-resistant Staphylococcus aureus in surface waters near industrial hog operation spray fields.

    PubMed

    Hatcher, S M; Myers, K W; Heaney, C D; Larsen, J; Hall, D; Miller, M B; Stewart, J R

    2016-09-15

    Industrial hog operations (IHOs) have been identified as a source of antibiotic-resistant Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). However, few studies have investigated the presence of antibiotic-resistant S. aureus in the environment near IHOs, specifically surface waters proximal to spray fields where IHO liquid lagoon waste is sprayed. Surface water samples (n=179) were collected over the course of approximately one year from nine locations in southeastern North Carolina and analyzed for the presence of presumptive MRSA using CHROMagar MRSA media. Culture-based, biochemical, and molecular tests, as well as matrix-assisted laser desorption/ionization-time of flight mass spectrometry were used to confirm that isolates that grew on CHROMagar MRSA media were S. aureus. Confirmed S. aureus isolates were then tested for susceptibility to 16 antibiotics and screened for molecular markers of MRSA (mecA, mecC) and livestock adaptation (absence of scn). A total of 12 confirmed MRSA were detected in 9 distinct water samples. Nine of 12 MRSA isolates were also multidrug-resistant (MDRSA [i.e., resistant to ≥3 antibiotic classes]). All MRSA were scn-positive and most (11/12) belonged to a staphylococcal protein A (spa) type t008, which is commonly associated with humans. Additionally, 12 confirmed S. aureus that were methicillin-susceptible (MSSA) were recovered, 7 of which belonged to spa type t021 and were scn-negative (a marker of livestock-adaptation). This study demonstrated the presence of MSSA, MRSA, and MDRSA in surface waters adjacent to IHO lagoon waste spray fields in southeastern North Carolina. To our knowledge, this is the first report of waterborne S. aureus from surface waters proximal to IHOs. PMID:27261430

  12. Characterisation of SCCmec elements in methicillin-resistant Staphylococcus aureus isolated from burn patients.

    PubMed

    Namvar, Amirmorteza Ebrahimzadeh; Afshar, Mastaneh; Asghari, Babak; Rastegar Lari, Abdolaziz

    2014-06-01

    Staphylococcus aureus is an important pathogen, especially in burn units all around the world. Because of the emergence of the β-lactam antibiotic-resistant strains since 1961, concern about the prevalence of methicillin-resistant S. aureus (MRSA) has increased in these units. Resistance to methicillin is mediated by penicillin-binding proteins (PBPs) that have enough affinity for binding to the β-lactam ring, but another kind of protein (PBP2α), which is encoded by the mecA gene, has a lower affinity for binding to these antibiotics. The mecA gene is transferred by SCCmec (staphylococcal cassette chromosome mec) as a mobile genetic element, exclusively found in the Staphylococcus genus. Identification of the frequency of the mecA gene, different SCCmec types and also its incidence may have benefit in surveillance prevention and control of MRSA strains in burn units. In this study, 40 S. aureus isolates were collected from patients hospitalised in Motahari burn center of Tehran, during 2012-2013. Conventional microbiological methods were applied and the confirmed isolates were stored at -20°C for molecular polymerase chain reaction (PCR) tests. The antibiotic resistance pattern was performed by disc diffusion method and finally the different SCCmec types were determined by specific primers. During this research, 40 isolates of S. aureus were collected from burn patients, of which (37.5%) of the specimens belonged to female patients and 62.5% to male patients. The aetiology of the burn was classified as follows: open flame (35%), liquid (32.5%), chemical (5%) and other (27.5%). By a disc diffusion method, no resistance pattern was observed to vancomycin and fosfomycin. Based on a multiplex PCR assay, the five different SCCmec types were detected as: 47.5% type III, 25% type IV, 10% type V, 10% type II and 7.5% type I. PMID:24211088

  13. Occurrence of methicillin-resistant Staphylococcus aureus in surface waters near industrial hog operation spray fields.

    PubMed

    Hatcher, S M; Myers, K W; Heaney, C D; Larsen, J; Hall, D; Miller, M B; Stewart, J R

    2016-09-15

    Industrial hog operations (IHOs) have been identified as a source of antibiotic-resistant Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). However, few studies have investigated the presence of antibiotic-resistant S. aureus in the environment near IHOs, specifically surface waters proximal to spray fields where IHO liquid lagoon waste is sprayed. Surface water samples (n=179) were collected over the course of approximately one year from nine locations in southeastern North Carolina and analyzed for the presence of presumptive MRSA using CHROMagar MRSA media. Culture-based, biochemical, and molecular tests, as well as matrix-assisted laser desorption/ionization-time of flight mass spectrometry were used to confirm that isolates that grew on CHROMagar MRSA media were S. aureus. Confirmed S. aureus isolates were then tested for susceptibility to 16 antibiotics and screened for molecular markers of MRSA (mecA, mecC) and livestock adaptation (absence of scn). A total of 12 confirmed MRSA were detected in 9 distinct water samples. Nine of 12 MRSA isolates were also multidrug-resistant (MDRSA [i.e., resistant to ≥3 antibiotic classes]). All MRSA were scn-positive and most (11/12) belonged to a staphylococcal protein A (spa) type t008, which is commonly associated with humans. Additionally, 12 confirmed S. aureus that were methicillin-susceptible (MSSA) were recovered, 7 of which belonged to spa type t021 and were scn-negative (a marker of livestock-adaptation). This study demonstrated the presence of MSSA, MRSA, and MDRSA in surface waters adjacent to IHO lagoon waste spray fields in southeastern North Carolina. To our knowledge, this is the first report of waterborne S. aureus from surface waters proximal to IHOs.

  14. Short communication: Antimicrobial resistance and virulence characterization of methicillin-resistant staphylococci isolates from bovine mastitis cases in Portugal.

    PubMed

    Seixas, R; Santos, J P; Bexiga, R; Vilela, C L; Oliveira, M

    2014-01-01

    Methicillin-resistant staphylococci (MRS) have already been reported as mastitis agents. Such bacterial species are a public health concern, and the characterization of their antimicrobial resistance and virulence profile is important to better control their dissemination. The present work evaluated the distribution of methicillin-resistance among 204 staphylococci from clinical (n=50) and subclinical (n=154) bovine mastitis. The presence ofthe mecA gene was determined by PCR. Phenotypic expression of coagulase, DNase, lipase, gelatinase, hemolytic enzymes, and biofilm production was evaluated. The presence of biofilm-related genes, icaA, icaD, and bap, was also determined. Antimicrobial resistance patterns for aminoglycosides, lincosamides, macrolides, fluoroquinolones, sulphonamides, tetracyclines, and fusidic acid were determined. Nineteen (9.3%) isolates were identified as MRS, and the presence of mecA in these isolates was confirmed by PCR. Virulence factors evaluation revealed that gelatinase was the most frequently detected (94.7%), followed by hemolysins (73.7%) and lipase (68.4%); 84.2% of the MRS isolates produced biofilm and icaA and icaD were detected in almost half of the MRS isolates (52.6%), but all were bap-negative. Resistance against other antimicrobial agents ranged from 0 (fusidic acid, ciprofloxacin, norfloxacin, enrofloxacin) to 100% (nalidixic acid). Resistance to nalidixic acid and nalidixic acid-tetracycline were the most common antimicrobial resistance profiles (31.6%). This study confirms that despite the low prevalence of MRS, isolates frequently express other virulence traits, especially biofilm, that may represent a serious challenge to clinicians.

  15. Liposome containing cinnamon oil with antibacterial activity against methicillin-resistant Staphylococcus aureus biofilm.

    PubMed

    Cui, Haiying; Li, Wei; Li, Changzhu; Vittayapadung, Saritporn; Lin, Lin

    2016-01-01

    The global burden of bacterial disease remains high and is set against a backdrop of increasing antimicrobial resistance. There is a pressing need for highly effective and natural antibacterial agents. In this work, the anti-biofilm effect of cinnamon oil on methicillin-resistant Staphylococcus aureus was evaluated. Then, cinnamon oil was encapsulated in liposomes to enhance its chemical stability. The anti-biofilm activities of the liposome-encapsulated cinnamon oil against MRSA biofilms on stainless steel, gauze, nylon membrane and non-woven fabrics were evaluated by colony forming unit determination. Scanning electron microscopy and laser scanning confocal microscopy analyses were employed to observe the morphological changes in MRSA biofilms treated with the encapsulated cinnamon oil. As a natural and safe spice, the cinnamon oil exhibited a satisfactory antibacterial performance on MRSA and its biofilms. The application of liposomes further improves the stability of antimicrobial agents and extends the action time.

  16. Is it time to replace vancomycin in the treatment of methicillin-resistant Staphylococcus aureus infections?

    PubMed

    van Hal, Sebastiaan J; Fowler, Vance G

    2013-06-01

    For more than 4 decades, vancomycin has been the antibiotic of choice for methicillin-resistant Staphylococcus aureus (MRSA) infections. Recently, infections due to isolates with high but susceptible vancomycin minimum inhibitory concentrations have been associated with additional treatment failures and patient mortality. These poorer outcomes may in part be explained by the inability of attaining appropriate vancomycin levels in these patients. However, assumptions that these poor outcomes are solely due to failure to achieve optimal serum levels of vancomycin are premature. The availability of effective alternatives further erodes the position of vancomycin as first-line therapy. The emergence of resistance and cost considerations, however, favor a more measured approach when using alternative antimicrobials. Collectively, the current available data suggest that the optimal therapy for MRSA infections remains unclear. In the absence of further data, the Infectious Diseases Society of America guidelines remain relevant and inform clinicians of best practice for treating patients with MRSA infections.

  17. Improved understanding of factors driving methicillin-resistant Staphylococcus aureus epidemic waves

    PubMed Central

    Chatterjee, Som S; Otto, Michael

    2013-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) remains one of the most important causes of nosocomial infections worldwide. Since the global spread of MRSA in the 1960s, MRSA strains have evolved with increased pathogenic potential. Notably, some strains are now capable of causing persistent infections not only in hospitalized patients but also in healthy individuals in the community. Furthermore, MRSA is increasingly associated with infections among livestock-associated workers, primarily because of transmission from animals to humans. Moreover, many MRSA strains have gained resistance to most available antibiotics. In this review, we will present current knowledge on MRSA epidemiology and discuss new endeavors being undertaken to understand better the molecular and epidemiological underpinnings of MRSA outbreaks. PMID:23861600

  18. Liposome containing cinnamon oil with antibacterial activity against methicillin-resistant Staphylococcus aureus biofilm.

    PubMed

    Cui, Haiying; Li, Wei; Li, Changzhu; Vittayapadung, Saritporn; Lin, Lin

    2016-01-01

    The global burden of bacterial disease remains high and is set against a backdrop of increasing antimicrobial resistance. There is a pressing need for highly effective and natural antibacterial agents. In this work, the anti-biofilm effect of cinnamon oil on methicillin-resistant Staphylococcus aureus was evaluated. Then, cinnamon oil was encapsulated in liposomes to enhance its chemical stability. The anti-biofilm activities of the liposome-encapsulated cinnamon oil against MRSA biofilms on stainless steel, gauze, nylon membrane and non-woven fabrics were evaluated by colony forming unit determination. Scanning electron microscopy and laser scanning confocal microscopy analyses were employed to observe the morphological changes in MRSA biofilms treated with the encapsulated cinnamon oil. As a natural and safe spice, the cinnamon oil exhibited a satisfactory antibacterial performance on MRSA and its biofilms. The application of liposomes further improves the stability of antimicrobial agents and extends the action time. PMID:26838161

  19. Analysis of Bacterial Biofilms on a Cochlear Implant Following Methicillin-Resistant Staphylococcus Aureus Infection.

    PubMed

    Im, Gi Jung; An, Yun Suk; Choi, June; Song, Jae Jun; Chae, Sung Won; Jung, Hak Hyun

    2015-12-01

    To demonstrate biofilm formations on a cochlear implant magnet of a pediatric patient suffering from a methicillin-resistant Staphylococcus aureus (MRSA) infection. The appearance of biofilm colonies was analyzed on different magnet sections. The appearance of MRSA biofilms on the surface of an explanted cochlear implant was analyzed by scanning electron microscopy (SEM), focusing on the pattern of extracellular polymeric substances (EPS) within the biofilms. SEM revealed unique biofilms with a three-dimensional EPS complex and tower-like formations. Biofilm configurations changed from the margin to the center of the magnet. Biofilms were solitary and scattered at the margin; large and plate-like in the center; and stacked in layers, forming towers and water channels, in the middle region. After a MRSA infection, biofilm formations were observed on the surface of a magnet. Bacterial biofilms provide optimal conditions for bacterial growth and antibiotic resistance and can cause intractable infections that lead to device failure.

  20. Antibacterial Characterization of Novel Synthetic Thiazole Compounds against Methicillin-Resistant Staphylococcus pseudintermedius

    PubMed Central

    Mohammad, Haroon; Reddy, P. V. Narasimha; Monteleone, Dennis; Mayhoub, Abdelrahman S.; Cushman, Mark; Hammac, G. Kenitra; Seleem, Mohamed N.

    2015-01-01

    Staphylococcus pseudintermedius is a commensal organism of companion animals that is a significant source of opportunistic infections in dogs. With the emergence of clinical isolates of S. pseudintermedius (chiefly methicillin-resistant S. pseudintermedius (MRSP)) exhibiting increased resistance to nearly all antibiotic classes, new antimicrobials and therapeutic strategies are urgently needed. Thiazole compounds have been previously shown to possess potent antibacterial activity against multidrug-resistant strains of Staphylococcus aureus of human and animal concern. Given the genetic similarity between S. aureus and S. pseudintermedius, this study explores the potential use of thiazole compounds as novel antibacterial agents against methicillin-sensitive S. pseudintermedius (MSSP) and MRSP. A broth microdilution assay confirmed these compounds exhibit potent bactericidal activity (at sub-microgram/mL concentrations) against both MSSA and MRSP clinical isolates while the MTS assay confirmed three compounds (at 10 μg/mL) were not toxic to mammalian cells. A time-kill assay revealed two derivatives rapidly kill MRSP within two hours. However, this rapid bactericidal activity was not due to disruption of the bacterial cell membrane indicating an alternative mechanism of action for these compounds against MRSP. A multi-step resistance selection analysis revealed compounds 4 and 5 exhibited a modest (two-fold) shift in activity over ten passages. Furthermore, all six compounds (at a subinihibitory concentration) demonstrated the ability to re-sensitize MRSP to oxacillin, indicating these compounds have potential use for extending the therapeutic utility of β-lactam antibiotics against MRSP. Metabolic stability analysis with dog liver microsomes revealed compound 3 exhibited an improved physicochemical profile compared to the lead compound. In addition to this, all six thiazole compounds possessed a long post-antibiotic effect (at least 8 hours) against MRSP

  1. Graphene oxide-silver nanocomposite as a promising biocidal agent against methicillin-resistant Staphylococcus aureus

    PubMed Central

    de Moraes, Ana Carolina Mazarin; Lima, Bruna Araujo; de Faria, Andreia Fonseca; Brocchi, Marcelo; Alves, Oswaldo Luiz

    2015-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) has been responsible for serious hospital infections worldwide. Nanomaterials are an alternative to conventional antibiotic compounds, because bacteria are unlikely to develop microbial resistance against nanomaterials. In the past decade, graphene oxide (GO) has emerged as a material that is often used to support and stabilize silver nanoparticles (AgNPs) for the preparation of novel antibacterial nanocomposites. In this work, we report the synthesis of the graphene-oxide silver nanocomposite (GO-Ag) and its antibacterial activity against relevant microorganisms in medicine. Materials and methods GO-Ag nanocomposite was synthesized through the reduction of silver ions (Ag+) by sodium citrate in an aqueous GO dispersion, and was extensively characterized using ultraviolet-visible absorption spectroscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. The antibacterial activity was evaluated by microdilution assays and time-kill experiments. The morphology of bacterial cells treated with GO-Ag was investigated via transmission electron microscopy. Results AgNPs were well distributed throughout GO sheets, with an average size of 9.4±2.8 nm. The GO-Ag nanocomposite exhibited an excellent antibacterial activity against methicillin-resistant S. aureus, Acinetobacter baumannii, Enterococcus faecalis, and Escherichia coli. All (100%) MRSA cells were inactivated after 4 hours of exposure to GO-Ag sheets. In addition, no toxicity was found for either pristine GO or bare AgNPs within the tested concentration range. Transmission electronic microscopy images offered insights into how GO-Ag nanosheets interacted with bacterial cells. Conclusion Our results indicate that the GO-Ag nanocomposite is a promising antibacterial agent against common nosocomial bacteria, particularly antibiotic-resistant MRSA. Morphological injuries on MRSA cells

  2. Descriptive Analysis of Antibiotic-Resistant Patterns of Methicillin-Resistant Staphylococcus aureus (MRSA) st398 Isolated from Healthy Swine

    PubMed Central

    Morcillo, Ana; Castro, Beatriz; Rodríguez-Álvarez, Cristobalina; Abreu, Rossana; Aguirre-Jaime, Armando; Arias, Angeles

    2015-01-01

    Background: Livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) such as the MRSA ST398 strain has spread all over the World and the most worrying aspect of this fact appears to be its capacity to easily spread to humans. The excessive use of antibiotics has made swine a reservoir of MRSA. The aim of the present study was to determine the antibiotic resistance profile of MRSA samples isolated from healthy swine of the island of Tenerife (Spain). Methods: A total of 256 MRSA isolates from swine samples and five MRSA isolates from pig worker samples were investigated for MRSA antibiotic resistant patterns. Results: Analysis of the susceptibility status of MRSA pig isolates revealed that 39 isolates were resistant to one antibiotic, 71 isolates were resistant to two antibiotics and 96 isolates were resistant to three or more antibiotics. SCCmec typing revealed the presence of types IV and V. Isolates having SCCmec IV had an increased resistance to the antimicrobial agents tested than those having SCCmec V. We observed significant differences when comparing the most common resistance patterns and SCCmec type. Conclusions: MRSA isolated from humans showed similar resistance to those isolated from pigs, excepting erythromycin, since all the workers’ isolates were sensitive to this antibiotic. The evolution of new MRSA clones has emphasized the need for infection control practices in animals and humans in close contact. PMID:25588155

  3. Recurrent Challenges for Clinicians: Emergence of Methicillin-Resistant Staphylococcus aureus, Vancomycin Resistance, and Current Treatment Options.

    PubMed

    Tarai, Bansidhar; Das, Poonam; Kumar, Dilip

    2013-07-01

    Gram-positive pathogens mainly, Staphylococcus aureus, Enterococcus and coagulase-negative Staphylococcus, are developing increasing resistance to glycopeptides that pose a problem in treating infections caused by these pathogens. Vancomycin is the treatment of choice in treating methicillin-resistant S. aureus (MRSA). Community-acquired MRSA is associated with infections in patients without recent history of hospital admission and without the classical risk factors for MRSA carriage (including healthcare personnel). MRSA poses new threats and challenges beyond the hospital with the emergence of community-acquired MRSA. Indiscriminate use of vancomycin leads to the emergence and spread of vancomycin resistance in multidrug resistant strains is of growing concern in the recent years. Minimum Inhibitory concentration (MIC) remains an important determinant in choosing the right antibiotics. Infections caused by MRSA strains with vancomycin MIC > 4 μg/mL leads to the vancomycin treatment failure. The Clinical Laboratory Standards Institute had also lowered the cut-off susceptibility and resistance breakpoints for vancomycin. Despite the availability of newer antimicrobial agents (Linezolid, Daptomycin, Tigecycline) for drug-resistant Gram-positive pathogens, clinicians and patients still need options for treatment of MRSA infection. There is a need to reduce the global burden of infections caused by Gram-positive pathogens and its resistant strains (mainly MRSA). Continuous efforts should be made to prevent the spread and the emergence of glycopeptide resistance by early detection of the resistant strains and using the proper infection control measures in the hospital setting. PMID:24701097

  4. Cell wall monoglycine cross-bridges and methicillin hypersusceptibility in a femAB null mutant of methicillin-resistant Staphylococcus aureus.

    PubMed Central

    Strandén, A M; Ehlert, K; Labischinski, H; Berger-Bächi, B

    1997-01-01

    The femAB operon is involved in the formation of the characteristic pentaglycine side chain of the staphylococcal peptidoglycan. Allele replacement of the femAB operon with the tetracycline resistance determinant tetK in a methicillin-resistant Staphylococcus aureus strain resulted in impaired growth, methicillin hypersusceptibility, and lysostaphin resistance. The usual pentaglycine cross-bridges were replaced by monoglycine bridges exclusively, and cross-linking of the peptidoglycan strands was drastically reduced. Complementation of the femAB null mutant by either femA or femAB resulted in the extension of the cross-bridges to a triglycine or a pentaglycine, respectively. This finding suggests that FemA is responsible for the formation of glycines 2 and 3, and FemB is responsible for formation of glycines 4 and 5, of the pentaglycine side chain of the peptidoglycan precursor. Moreover, it can be deduced that addition of the first glycine must occur by a femAB-independent mechanism. PMID:8981974

  5. Insights on Evolution of Virulence and Resistance from the Complete Genome Analysis of an Early Methicillin-Resistant Staphylococcus aureus Strain and a Biofilm-Producing Methicillin-Resistant Staphylococcus epidermidis Strain†

    PubMed Central

    Gill, Steven R.; Fouts, Derrick E.; Archer, Gordon L.; Mongodin, Emmanuel F.; DeBoy, Robert T.; Ravel, Jacques; Paulsen, Ian T.; Kolonay, James F.; Brinkac, Lauren; Beanan, Mauren; Dodson, Robert J.; Daugherty, Sean C.; Madupu, Ramana; Angiuoli, Samuel V.; Durkin, A. Scott; Haft, Daniel H.; Vamathevan, Jessica; Khouri, Hoda; Utterback, Terry; Lee, Chris; Dimitrov, George; Jiang, Lingxia; Qin, Haiying; Weidman, Jan; Tran, Kevin; Kang, Kathy; Hance, Ioana R.; Nelson, Karen E.; Fraser, Claire M.

    2005-01-01

    Staphylococcus aureus is an opportunistic pathogen and the major causative agent of numerous hospital- and community-acquired infections. Staphylococcus epidermidis has emerged as a causative agent of infections often associated with implanted medical devices. We have sequenced the ∼2.8-Mb genome of S. aureus COL, an early methicillin-resistant isolate, and the ∼2.6-Mb genome of S. epidermidis RP62a, a methicillin-resistant biofilm isolate. Comparative analysis of these and other staphylococcal genomes was used to explore the evolution of virulence and resistance between these two species. The S. aureus and S. epidermidis genomes are syntenic throughout their lengths and share a core set of 1,681 open reading frames. Genome islands in nonsyntenic regions are the primary source of variations in pathogenicity and resistance. Gene transfer between staphylococci and low-GC-content gram-positive bacteria appears to have shaped their virulence and resistance profiles. Integrated plasmids in S. epidermidis carry genes encoding resistance to cadmium and species-specific LPXTG surface proteins. A novel genome island encodes multiple phenol-soluble modulins, a potential S. epidermidis virulence factor. S. epidermidis contains the cap operon, encoding the polyglutamate capsule, a major virulence factor in Bacillus anthracis. Additional phenotypic differences are likely the result of single nucleotide polymorphisms, which are most numerous in cell envelope proteins. Overall differences in pathogenicity can be attributed to genome islands in S. aureus which encode enterotoxins, exotoxins, leukocidins, and leukotoxins not found in S. epidermidis. PMID:15774886

  6. Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) isolates of swine origin form robust biofilms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methicillin-resistant Staphylococcus aureus (MRSA) colonization of livestock animals is common and prevalence rates for pigs have been reported to be as high as 49%. One hypothesis to explain the high prevalence of MRSA in swine herds is the ability of these organisms to exist as biofilms. To invest...

  7. Prevalence of methicillin-resistant staphylococci species isolated from computer keyboards located in secondary and postsecondary schools.

    PubMed

    Boa, Tyler T; Rahube, Teddie O; Fremaux, Bastien; Levett, Paul N; Yost, Christopher K

    2013-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a public health threat within the general community, thereby warranting identification of MRSA reservoirs within the community. Computer terminals in schools were sampled for S. aureus and methicillin-resistant staphylococci. The overall prevalence of MRSA on computer keyboards was low: 0.68% for a postsecondary institution and 2% and 0% for two secondary institutes. The MRSA isolate from the postsecondary institution did not correspond to the Canadian epidemic clusters, but is related to the USA 700 cluster, which contains strains implicated in outbreaks within the U.S. The isolate from the secondary institute's keyboard was typed as CMRSA7 (USA 400), a strain that has been implicated in both Canadian and U.S. epidemics. Methicillin-resistant S. haemolyticus and S. epidermidis were also isolated from keyboards, indicating that a mixed community of methicillin-resistant staphylococci can be present on keyboards. Although the prevalence was low, the presence of MRSA combined with the high volume of traffic on these student computer terminals demonstrates the potential for public-access computer terminals and computer rooms at educational institutes to act as reservoirs.

  8. Multiplex PCR assay for identification of six different Staphylococcus spp. and simultaneous detection of methicillin and mupirocin resistance.

    PubMed

    Campos-Peña, E; Martín-Nuñez, E; Pulido-Reyes, G; Martín-Padrón, J; Caro-Carrillo, E; Donate-Correa, J; Lorenzo-Castrillejo, I; Alcoba-Flórez, J; Machín, F; Méndez-Alvarez, S

    2014-07-01

    We describe a new, efficient, sensitive, and fast single-tube multiple-PCR protocol for the identification of the most clinically significant Staphylococcus spp. and the simultaneous detection of the methicillin and mupirocin resistance loci. The protocol identifies at the species level isolates belonging to S. aureus, S. epidermidis, S. haemolyticus, S. hominis, S. lugdunensis, and S. saprophyticus.

  9. Use of the cobas 4800 system for the rapid detection of toxigenic Clostridium difficile and methicillin-resistant Staphylococcus aureus.

    PubMed

    Moure, Raquel; Cañizares, Ángeles; Muíño, María; Lobato, Margarita; Fernández, Ana; Rodríguez, María; Gude, Maria José; Tomás, Maria; Bou, Germán

    2016-01-01

    The new cobas® Cdiff and cobas® MRSA/SA tests were compared with conventional methods for the rapid detection of toxigenic Clostridium difficile and methicillin-resistant Staphylococcus aureus. The final concordance between cobas Cdiff Test and GDH/toxin gene screening was 97.62% and between cobas MRSA/SA Test and chromogenic culture, 91.30%, respectively.

  10. Efficacy of alcohol gel for removal of methicillin-resistant Staphylococcus aureus from hands of colonized patients.

    PubMed

    Sunkesula, Venkata; Kundrapu, Sirisha; Macinga, David R; Donskey, Curtis J

    2015-02-01

    Of 82 patients with methicillin-resistant Staphylococcus aureus (MRSA) colonization, 67 (82%) had positive hand cultures for MRSA. A single application of alcohol gel (2 mL) consistently reduced the burden of MRSA on hands. However, incomplete removal of MRSA was common, particularly in those with a high baseline level of recovery. PMID:25633009

  11. Introduction of plasmid DNA into an ST398 livestock-associated methicillin-resistant Staphylococcus aureus strain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    MRS926 is a livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) strain of sequence type (ST) 398. In order to facilitate in vitro and in vivo studies of this strain, we sought to tag it with a fluorescent marker. We cloned a codon-optimized gene for TurboGFP into a shuttle vector...

  12. Potential role of pet animals in household transmission of methicillin-resistant Staphylococcus aureus: a narrative review.

    PubMed

    Bramble, Manuel; Morris, Daniel; Tolomeo, Pam; Lautenbach, Ebbing

    2011-06-01

    In this narrative review, we found numerous reports suggesting that dogs and cats may play a role in household methicillin-resistant Staphylococcus aureus (MRSA) transmission and recurrent MRSA infection in human contacts. Future work should emphasize elucidating more clearly the prevalence of MRSA in household pets and characterize transmission dynamics of MRSA humans and pet animals.

  13. Prevalence and characterization of Methicillin-resistant Staphylococcus aureus isolates from retail meat and humans in Georgia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is increasing interest in the presence of Staphylococcus aureus, specifically methicillin-resistant S. aureus (MRSA), on retail meat products. In this study, staphylococci were isolated from retail pork and retail beef in Georgia and MRSA from the products were compared to human MRSA from the...

  14. Community-acquired methicillin-resistant Staphylococcus aureus infections in two scuba divers returning from the Philippines.

    PubMed

    Bochet, Mélanie; Francois, Patrice; Longtin, Yves; Gaide, Olivier; Renzi, Gesuele; Harbarth, Stephan

    2008-01-01

    We describe two patients who had skin infection due to identical strains of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) after returning from the Philippines. Both patients did not share risk factors for CA-MRSA acquisition besides scuba diving. Scuba diving equipment may represent a possible new mode of acquisition of CA-MRSA.

  15. Potential role of pet animals in household transmission of methicillin-resistant Staphylococcus aureus: a narrative review.

    PubMed

    Bramble, Manuel; Morris, Daniel; Tolomeo, Pam; Lautenbach, Ebbing

    2011-06-01

    In this narrative review, we found numerous reports suggesting that dogs and cats may play a role in household methicillin-resistant Staphylococcus aureus (MRSA) transmission and recurrent MRSA infection in human contacts. Future work should emphasize elucidating more clearly the prevalence of MRSA in household pets and characterize transmission dynamics of MRSA humans and pet animals. PMID:21142959

  16. Alternative use for spectra MRSA chromogenic agar in detection of methicillin-resistant Staphylococcus aureus from positive blood cultures.

    PubMed

    Peterson, Jess F; Dionisio, Alexander A; Riebe, Katherine M; Hall, Gerri S; Wilson, Deborah A; Whittier, Susan; Dipersio, Joseph R; Ledeboer, Nathan A

    2010-06-01

    Spectra MRSA agar (Remel, Lenexa, KS), a novel chromogenic medium originally developed to detect methicillin-resistant Staphylococcus aureus (MRSA) from nasal swabs, was evaluated in this multicenter study for the detection of MRSA from positive blood cultures exhibiting Gram-positive cocci upon initial Gram staining.

  17. Multiplex PCR assay for identification of six different Staphylococcus spp. and simultaneous detection of methicillin and mupirocin resistance.

    PubMed

    Campos-Peña, E; Martín-Nuñez, E; Pulido-Reyes, G; Martín-Padrón, J; Caro-Carrillo, E; Donate-Correa, J; Lorenzo-Castrillejo, I; Alcoba-Flórez, J; Machín, F; Méndez-Alvarez, S

    2014-07-01

    We describe a new, efficient, sensitive, and fast single-tube multiple-PCR protocol for the identification of the most clinically significant Staphylococcus spp. and the simultaneous detection of the methicillin and mupirocin resistance loci. The protocol identifies at the species level isolates belonging to S. aureus, S. epidermidis, S. haemolyticus, S. hominis, S. lugdunensis, and S. saprophyticus. PMID:24829244

  18. Evaluation of methicillin-resistant Staphylococcus aureus skin and soft-tissue infection prevention strategies at a military training center.

    PubMed

    Morrison, Stephanie M; Blaesing, Carl R; Millar, Eugene V; Chukwuma, Uzo; Schlett, Carey D; Wilkins, Kenneth J; Tribble, David R; Ellis, Michael W

    2013-08-01

    Military trainees are at high risk for skin and soft-tissue infections (SSTIs), especially those caused by methicillin-resistant Staphylococcus aureus (MRSA). A multicomponent hygiene-based SSTI prevention strategy was implemented at a military training center. After implementation, we observed 30% and 64% reductions in overall and MRSA-associated SSTI rates, respectively.

  19. Importance of methicillin-resistant Staphylococcus aureus eradication in carriers to prevent postoperative methicillin-resistant Staphylococcus aureus surgical site infection.

    PubMed

    Pofahl, Walter E; Ramsey, Keith M; Nobles, Delores L; Cochran, M Kathy; Goettler, Claudia

    2011-01-01

    Although infrequent, postoperative methicillin-resistant Staphylococcus aureus (MRSA) surgical site infection (SSI) is associated with significant morbidity and cost. Previous studies have identified the importance of MRSA screening to diminish the risk of postoperative MRSA SSI. The current study quantifies the importance of eradication of the MRSA carrier state to prevent MRSA SSI. Beginning February 2007, all admissions to an 800-bed tertiary care hospital were screened for MRSA by nasal swab using rapid polymerase chain reaction-based testing. Patients found to be nasal carriers of MRSA were treated with 2 per cent mupirocin nasal ointment and 4 per cent chlorhexidine soap before surgery. The subset of patients undergoing procedures that are part of the Surgical Care Improvement Project (SCIP) were followed for MRSA SSI (n = 8980). The results of preoperative MRSA screening and eradication of the carrier state were analyzed. Since the initiation of universal MRSA screening, 11 patients undergoing SCIP procedures have developed MRSA SSI (0.12%). Of these, six patients (55%) had negative preoperative screens. Of the five patients with positive preoperative screens, only one received treatment to eradicate the carrier state. In patients who develop MRSA SSI, failure to treat the carrier state before surgery results in MRSA SSI. PMID:21396301

  20. Characterization of Methicillin Resistant Staphylococcus aureus isolated from human and animal samples in Egypt.

    PubMed

    Bendary, M M; Solyman, S M; Azab, M M; Mahmoud, N F; Hanora, A M

    2016-02-29

    Staphylococcus aureus (S. aureus) has been one of the most problematic pathogens. Methicillin Resistant S. aureus (MRSA) has emerged as a major concern for both human and animal. Antibiotic resistance genes dissemination might be possible between human and animal bacteria. The aim of this study is to show phenotypic and genotypic diversity of human and animal MRSA isolates. Antibiogram typing and biofilm production were used as a primary phenotypic typing tool for the characterization of (40) animal and (38) human MRSA isolates. Genetic typing based on sequencing of 16S rRNA gene and virulence gene profiles were done. Antimicrobial resistance profiles of the animal isolates showed little evidence of widespread of resistance, although this was seen in many human isolates. The biofilm production was detected in higher percentage among animal isolates. Based on the genetic typing and multiple antibiotic resistance (MAR) index, the majority of animal isolates clustered into lineages that were not found in human isolates. Animal and human MRSA isolates showed diversity in antibiotic resistance and virulence gene profiles may be due to host adaptation or chances for contamination between the two hosts were not present in our study.

  1. Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus Isolated from Australian Veterinarians.

    PubMed

    Groves, Mitchell D; Crouch, Bethany; Coombs, Geoffrey W; Jordan, David; Pang, Stanley; Barton, Mary D; Giffard, Phil; Abraham, Sam; Trott, Darren J

    2016-01-01

    This work investigated the molecular epidemiology and antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolated from veterinarians in Australia in 2009. The collection (n = 44) was subjected to extensive molecular typing (MLST, spa, SCCmec, dru, PFGE, virulence and antimicrobial resistance genotyping) and antimicrobial resistance phenotyping by disk diffusion. MRSA was isolated from Australian veterinarians representing various occupational emphases. The isolate collection was dominated by MRSA strains belonging to clonal complex (CC) 8 and multilocus sequence type (ST) 22. CC8 MRSA (ST8-IV [2B], spa t064; and ST612-IV [2B], spa variable,) were strongly associated with equine practice veterinarians (OR = 17.5, 95% CI = 3.3-92.5, P < 0.001) and were often resistant to gentamicin and rifampicin. ST22-IV [2B], spa variable, were strongly associated with companion animal practice veterinarians (OR = 52.5, 95% CI = 5.2-532.7, P < 0.001) and were resistant to ciprofloxacin. A single pig practice veterinarian carried ST398-V [5C2], spa t1451. Equine practice and companion animal practice veterinarians frequently carried multiresistant-CC8 and ST22 MRSA, respectively, whereas only a single swine specialist carried MRSA ST398. The presence of these strains in veterinarians may be associated with specific antimicrobial administration practices in each animal species.

  2. Methicillin-Resistant Staphylococcus aureus Recovered from Healthcare- and Community-Associated Infections in Egypt.

    PubMed

    Abdel-Maksoud, Mohamed; El-Shokry, Mona; Ismail, Ghada; Hafez, Soad; El-Kholy, Amani; Attia, Ehab; Talaat, Maha

    2016-01-01

    Background. Methicillin-resistant Staphylococcus aureus (MRSA) has created significant epidemiological, infection-control, and therapeutic management challenges during the past three decades. Aim. To analyze the pattern of resistance of healthcare- and community-associated MRSA in Egypt and the trend of resistance of HA-MRSA over time (2005-2013). Methods. MRSA isolates were recovered from healthcare-associated (HA) and community-associated (CA) Staphylococcus aureus (S. aureus) infections. They were tested against 11 antimicrobial discs and the minimal inhibitory concentration (MIC) of vancomycin was determined. Inducible clindamycin resistance (iMLSB) was also screened using D-test. Findings. Of 631 S. aureus, MRSA was identified in 343 (76.6%) and 21 (11.5%) of HA and CA S. aureus isolates, respectively. The proportion of HA-MRSA increased significantly from 48.6% in 2005 to 86.8% in 2013 (p value < 0.001). Multidrug resistance (MDR) was observed in 85.8% of HA-MRSA and 48.6% of CA-MRSA. Vancomycin intermediate resistant S. aureus (VISA) was detected in 1.2% of HA-MRSA and none was detected in CA-MRSA. Among HA-MRSA strains, 5.3% showed iMLSB compared to 9.5% among CA-MRSA. Conclusion. The upsurge of the prevalence rates of HA-MRSA over time is alarming and urges for an effective infection control strategy and continuous monitoring of antimicrobial use.

  3. Methicillin-Resistant Staphylococcus aureus Recovered from Healthcare- and Community-Associated Infections in Egypt

    PubMed Central

    Abdel-Maksoud, Mohamed; Ismail, Ghada; Hafez, Soad; El-Kholy, Amani; Attia, Ehab; Talaat, Maha

    2016-01-01

    Background. Methicillin-resistant Staphylococcus aureus (MRSA) has created significant epidemiological, infection-control, and therapeutic management challenges during the past three decades. Aim. To analyze the pattern of resistance of healthcare- and community-associated MRSA in Egypt and the trend of resistance of HA-MRSA over time (2005–2013). Methods. MRSA isolates were recovered from healthcare-associated (HA) and community-associated (CA) Staphylococcus aureus (S. aureus) infections. They were tested against 11 antimicrobial discs and the minimal inhibitory concentration (MIC) of vancomycin was determined. Inducible clindamycin resistance (iMLSB) was also screened using D-test. Findings. Of 631 S. aureus, MRSA was identified in 343 (76.6%) and 21 (11.5%) of HA and CA S. aureus isolates, respectively. The proportion of HA-MRSA increased significantly from 48.6% in 2005 to 86.8% in 2013 (p value < 0.001). Multidrug resistance (MDR) was observed in 85.8% of HA-MRSA and 48.6% of CA-MRSA. Vancomycin intermediate resistant S. aureus (VISA) was detected in 1.2% of HA-MRSA and none was detected in CA-MRSA. Among HA-MRSA strains, 5.3% showed iMLSB compared to 9.5% among CA-MRSA. Conclusion. The upsurge of the prevalence rates of HA-MRSA over time is alarming and urges for an effective infection control strategy and continuous monitoring of antimicrobial use. PMID:27433480

  4. Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus Isolated from Australian Veterinarians

    PubMed Central

    Groves, Mitchell D.; Crouch, Bethany; Coombs, Geoffrey W.; Jordan, David; Pang, Stanley; Barton, Mary D.; Giffard, Phil

    2016-01-01

    This work investigated the molecular epidemiology and antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolated from veterinarians in Australia in 2009. The collection (n = 44) was subjected to extensive molecular typing (MLST, spa, SCCmec, dru, PFGE, virulence and antimicrobial resistance genotyping) and antimicrobial resistance phenotyping by disk diffusion. MRSA was isolated from Australian veterinarians representing various occupational emphases. The isolate collection was dominated by MRSA strains belonging to clonal complex (CC) 8 and multilocus sequence type (ST) 22. CC8 MRSA (ST8-IV [2B], spa t064; and ST612-IV [2B], spa variable,) were strongly associated with equine practice veterinarians (OR = 17.5, 95% CI = 3.3–92.5, P < 0.001) and were often resistant to gentamicin and rifampicin. ST22-IV [2B], spa variable, were strongly associated with companion animal practice veterinarians (OR = 52.5, 95% CI = 5.2–532.7, P < 0.001) and were resistant to ciprofloxacin. A single pig practice veterinarian carried ST398-V [5C2], spa t1451. Equine practice and companion animal practice veterinarians frequently carried multiresistant-CC8 and ST22 MRSA, respectively, whereas only a single swine specialist carried MRSA ST398. The presence of these strains in veterinarians may be associated with specific antimicrobial administration practices in each animal species. PMID:26735694

  5. Development of a prediction rule for methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococcus carriage in a Veterans Affairs Medical Center population.

    PubMed

    Riedel, Stefan; Von Stein, Diana; Richardson, Kelly; Page, Joann; Miller, Sara; Winokur, Patricia; Diekema, Daniel

    2008-10-01

    A history of hospital admission in the prior year was the most sensitive predictor of methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus colonization at admission to a Veterans Affairs Medical Center (VAMC) but missed more than one-third of carriers and required screening more than one-half of admitted patients. PMID:18702599

  6. Prevalence of methicillin-resistant Staphylococcus aureus nasal colonization among medical students in Jeddah, Saudi Arabia

    PubMed Central

    Zakai, Shadi A.

    2015-01-01

    Objectives: To identify Methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage status among medical students during their clinical rotations. Methods: This cross-sectional study detected the prevalence of MRSA among medical students at King Abdulaziz University (KAU), Jeddah, Saudi Arabia, using molecular approaches. Nasal swabs were collected from 150 internship and sixth-year medical students between September 2014 and January 2015, and compared with the control group of 32 third-year medical students who were not exposed to clinical work. Polymerase chain reaction (PCR) screening was performed to identify Staphylococcus aureus (S. aureus) nuc gene, and an additional PCR was performed on S. aureus positive samples to detect the presence of mecA gene. Results: Out of 150 students screened, 38 were nasal carriers of S. aureus. The prevalence of methicillin-sensitive S. aureus (MSSA) carriers was 18.7% (n=28), whereas 10 students (6.7%) were mecA-positive, representing MRSA carriers. Interns carry MRSA more than 6th year students and students who were not exposed to clinical work (p<0.05), while MSSA is found more in students who were not exposed to clinical work (p<0.01). Conclusion: We found MRSA carriers among medical students at KAU, which showed a possible contribution of this group to transmit infection to hospitalized patients. Medical students must receive sufficient knowledge regarding control measures to avoid spread of this infection in hospitals. PMID:26108584

  7. Alkyl Gallates, Intensifiers of β-Lactam Susceptibility in Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Shibata, Hirofumi; Kondo, Kyoko; Katsuyama, Ryo; Kawazoe, Kazuyoshi; Sato, Yoichi; Murakami, Kotaro; Takaishi, Yoshihisa; Arakaki, Naokatu; Higuti, Tomihiko

    2005-01-01

    We found that ethyl gallate purified from a dried pod of tara (Caesalpinia spinosa) intensified β-lactam susceptibility in methicillin-resistant and methicillin-sensitive strains of Staphylococcus aureus (MRSA and MSSA strains, respectively). This compound and several known alkyl gallates were tested with MRSA and MSSA strains to gain new insights into their structural functions in relation to antimicrobial and β-lactam susceptibility-intensifying activities. The maximum activity of alkyl gallates against MRSA and MSSA strains occurred at 1-nonyl and 1-decyl gallate, with an MIC at which 90% of the isolates tested were inhibited of 15.6 μg/ml. At concentrations lower than the MIC, alkyl gallates synergistically elevated the susceptibility of MRSA and MSSA strains to β-lactam antibiotics. Such a synergistic activity of the alkyl gallates appears to be specific for β-lactam antibiotics, because no significant changes were observed in the MICs of other classes of antibiotics examined in this study. The length of the alkyl chain was also associated with the modifying activity of the alkyl gallates, and the optimum length was C5 to C6. The present work clearly demonstrates that the length of the alkyl chain has a key role in the elevation of susceptibility to β-lactam antibiotics. PMID:15673731

  8. Electric stimulations mediated beta lactam resistance reversal and correlation with growth dynamics of community acquired methicillin resistant Staphylococcus aureus.

    PubMed

    Kainthola, Anup; Uniyal, Akshat; Srivastava, Nidhi; Bhatt, Ajay B

    2015-08-01

    The community associated methicillin resistant Staphylococcus aureus (CA-MRSA) is a serious issue of public health. Here, we conducted an experimental approach to determine: (i) the optimal significant stimulation range of electrical current for effective checking of CA-MRSA growth; (ii) the effect of electrical stimulations on methicillin susceptibility and possible beta lactam resistance reversal; and (iii) the variation in the level of ATP as function of exposure to electric current. An 8 chambered electrical system was developed for DC flow in control and test sets, with and without drug (oxacillin 4 mg/ml). Measurement of growth by CFU/ml and spectrometry, susceptibility and ATP levels were calculated and interpreted. Linear pattern in reduction of ATP was observed with respect to the intensity of electric current (EC) and an enhanced inhibitory effect was explicit with 1000 microampere (μA) with 30 min exposure. At 4000 μA exposure to DC at 180 min and in combination of drug (μA+D), the growth of CA-MRSA was substantially checked to 0.23 absorbance in comparison to current without drug and the effect of DC electrical current to the culture showed that 10 μA, 100 μA and 4000 μA current exposure in combination of oxacillin (μA+D), markedly reduced the CFU to an average of 256.4. ATP level was linearly reduced with exposure to EC.

  9. Methicillin-resistant Staphylococcus aureus (MRSA) as a cause of nosocomial wound infections.

    PubMed

    Sisirak, Maida; Zvizdic, Amra; Hukic, Mirsada

    2010-02-01

    Postoperative wound infections represent about 16% of hospital-acquired infections. Staphylococcus aureus is the most common cause of nosocomial wound infections. Increased frequency of Methicillin-resistant Staphylococcus aureus (MRSA) in hospitalized patients and possibility of vancomycin resistance requires permanent control of MRSA spread in the hospital.The purpose of this study was to analyse the frequency of Methicillin-resistant Staphylococcus aureus (MRSA) in the swabs taken from the surgical wounds, the presence of MRSA infection in surgical departments and to examine antimicrobial susceptibility of MRSA isolates. Wound swabs were examined from January 2006 to December 2008. The isolates were identified by conventional methods. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc-diffusion method as per NCCLS guidelines.A total of 5755 wound swabs were examined: 938 (16,3%) swabs were sterile and 4817 (83,7%) were positive. Staphylococcus aureus was isolated in 1050 (22,0%) swabs and it was the most common cause of wound infections. MRSA was isolated from 12,4% samples in 2006, from 6,7% samples in 2007 and from 3,7% samples during 2008. Wound infections caused by MRSA dominated in the department of plastic surgery (24,4%) and in the department of orthopaedic surgery (24,1%). Antimicrobial susceptibility testing showed that 73% of MRSA isolates were with the same antibiotic sensitivity pattern (antibiotyp)-sensitive only to vancomycin, tetracycline, fucid acid and trimethoprim/sulfamethoxasole. Our results show decreasing of MRSA infection in the surgical wards. These results appear to be maintained with strategies for preventing nosocomial infection: permanent education, strong application of protocols and urging the implementation of strict infection control policy.

  10. Staphylococcal Cassette Chromosome mec Types Among Methicillin-Resistant Staphylococcus aureus in Northern Iran

    PubMed Central

    Taherirad, Akram; Jahanbakhsh, Roghayeh; Shakeri, Fatemeh; Anvary, Shaghayegh; Ghaemi, Ezzat Allah

    2016-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial and community-acquired infections around the world. Staphylococcal cassette chromosome mec (SCCmec) typing methods are often used to study MRSA molecular epidemiology. Objectives The current study was designed to explore the distribution profiles of different SCCmec types among methicillin-resistant S. aureus strains isolated from hospitals in Gorgan, in northern Iran, and to correlate the types into observed bacterial virulence factors. Materials and Methods Staphylococcal cassette chromosome mec typing of 62 MRSA strains isolated from patients and health-care workers in Gorgan was performed using multiplex polymerase chain reaction (PCR) assay. The prevalence of the strains was then compared according to isolation source, antibiotic susceptibility profiles, biofilm production, and the presence of the Panton-Valentine gene in isolates. Results The most common SCCmec type was type III, with a frequency rate of 76%, followed by types IV, I, and V, with frequency rates of 11.2%, 4.8%, and 3.2%, respectively; three isolates (4.8%) were not typeable by this method. SCCmec type I was only isolated from blood culture, and types IV and V were mainly isolated from wounds and urine samples; SCCmec type III was isolated from all of the clinically samples. All of the MRSA strains that were isolated from healthy carriers were type III. Multidrug resistance in the type III strains was higher compared to the other types. The frequencies of Panton-Valentine and biofilm production were significantly lower in the type III strains compared to the other SCCmec types (P < 0.05). Conclusions Similarly to other geographical regions of Iran, the SCCmec type III MRSA strain was the most frequently isolated strain from patients in Gorgan. Staphylococcal cassette chromosome mec type III showed fewer virulence factors compared to other SCCmec types. PMID:27800133

  11. Methicillin-Resistant Staphylococcus aureus (MRSA) Detected at Four U.S. Wastewater Treatment Plants

    PubMed Central

    Goldstein, Rachel E. Rosenberg; Micallef, Shirley A.; Gibbs, Shawn G.; Davis, Johnnie A.; He, Xin; George, Ashish; Kleinfelter, Lara M.; Schreiber, Nicole A.; Mukherjee, Sampa; Joseph, Sam W.

    2012-01-01

    Background: The incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections is increasing in the United States, and it is possible that municipal wastewater could be a reservoir of this microorganism. To date, no U.S. studies have evaluated the occurrence of MRSA in wastewater. Objective: We examined the occurrence of MRSA and methicillin-susceptible S. aureus (MSSA) at U.S. wastewater treatment plants. Methods: We collected wastewater samples from two Mid-Atlantic and two Midwest wastewater treatment plants between October 2009 and October 2010. Samples were analyzed for MRSA and MSSA using membrane filtration. Isolates were confirmed using biochemical tests and PCR (polymerase chain reaction). Antimicrobial susceptibility testing was performed by Sensititre® microbroth dilution. Staphylococcal cassette chromosome mec (SCCmec) typing, Panton-Valentine leucocidin (PVL) screening, and pulsed field gel electrophoresis (PFGE) were performed to further characterize the strains. Data were analyzed by two-sample proportion tests and analysis of variance. Results: We detected MRSA (n = 240) and MSSA (n = 119) in 22 of 44 (50%) and 24 of 44 (55%) wastewater samples, respectively. The odds of samples being MRSA-positive decreased as treatment progressed: 10 of 12 (83%) influent samples were MRSA-positive, while only one of 12 (8%) effluent samples was MRSA-positive. Ninety-three percent and 29% of unique MRSA and MSSA isolates, respectively, were multidrug resistant. SCCmec types II and IV, the pvl gene, and USA types 100, 300, and 700 (PFGE strain types commonly found in the United States) were identified among the MRSA isolates. Conclusions: Our findings raise potential public health concerns for wastewater treatment plant workers and individuals exposed to reclaimed wastewater. Because of increasing use of reclaimed wastewater, further study is needed to evaluate the risk of exposure to antibiotic-resistant bacteria in treated

  12. Genotyping of Methicillin Resistant Staphylococcus aureus from Tertiary Care Hospitals in Coimbatore, South India

    PubMed Central

    Neetu, Toms John Peedikayil; Murugan, Sevanan

    2016-01-01

    Background: Globally, methicillin resistant Staphylococcus aureus (MRSA) is one of the most common pathogens that causes hospital- and community-acquired infections. The use of molecular typing methods is essential for determining the origin of the isolates, their clonal relations, and also epidemiological investigations. Objective: The purpose of this study was to determine the prevalence of antibiotic-resistant MRSA investigate the accessory gene regulator (agr) and staphylococcal cassette chromosome mec (SCCmec) types and perform multilocus sequence typing (MLST). Furthermore, the minimum inhibitory concentration of MRSA isolates was determined for vancomycin and daptomycin. Materials and Methods: Two hundred and fifty-nine MRSA isolates were collected from Tertiary Care Hospitals in Coimbatore. Disk diffusion method was employed to assess the sensitivity of MRSA isolates to selected antibiotics and genetic analysis was performed using SCCmec, agr, and MLST typing by multiplex-polymerase chain reaction strategy. Minimal inhibitory concentration (MIC) was determined using Ezy MIC (vancomycin) and Biomerieux (daptomycin) E-test strip. Results: Of 259 MRSA isolates, 209 (80.7%) were confirmed as methicillin resistant. Antibiotic susceptibility pattern revealed that all the MRSA isolates were 100% sensitive to linezolid, rifampicin, teicoplanin, and vancomycin. MIC results showed that of 209 MRSA isolates, 10 were found to be vancomycin intermediate S. aureus and 100% of the MRSA isolates were daptomycin-susceptible. The agr group I and SCCmec Type III were the major type among MRSA isolates. In addition to these MLST typing revealed the prevalence of sequence type (ST) 239 (SLV of ST8) among the MRSA isolates. Conclusion: This study confirms that ST239 (Brazilian clone) of MRSA is predominant in this region which is responsible for the hospital-acquired MRSA infections. Thus, the study also suggests that vancomycin and daptomycin can still be used as an alternative

  13. Origin and Evolution of European Community-Acquired Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Wirth, Thierry; Andersen, Paal S.; Skov, Robert L.; De Grassi, Anna; Simões, Patricia Martins; Tristan, Anne; Petersen, Andreas; Aziz, Maliha; Kiil, Kristoffer; Cirković, Ivana; Udo, Edet E.; del Campo, Rosa; Vuopio-Varkila, Jaana; Ahmad, Norazah; Tokajian, Sima; Peters, Georg; Schaumburg, Frieder; Olsson-Liljequist, Barbro; Givskov, Michael; Driebe, Elizabeth E.; Vigh, Henrik E.; Shittu, Adebayo; Ramdani-Bougessa, Nadjia; Rasigade, Jean-Philippe; Price, Lance B.; Vandenesch, Francois; Larsen, Anders R.; Laurent, Frederic

    2014-01-01

    ABSTRACT Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) was recognized in Europe and worldwide in the late 1990s. Within a decade, several genetically and geographically distinct CA-MRSA lineages carrying the small SCCmec type IV and V genetic elements and the Panton-Valentine leukocidin (PVL) emerged around the world. In Europe, the predominant CA-MRSA strain belongs to clonal complex 80 (CC80) and is resistant to kanamycin/amikacin and fusidic acid. CC80 was first reported in 1993 but was relatively rare until the late 1990s. It has since been identified throughout North Africa, the Middle East, and Europe, with recent sporadic reports in sub-Saharan Africa. While strongly associated with skin and soft tissue infections, it is rarely found among asymptomatic carriers. Methicillin-sensitive S. aureus (MSSA) CC80 strains are extremely rare except in sub-Saharan Africa. In the current study, we applied whole-genome sequencing to a global collection of both MSSA and MRSA CC80 isolates. Phylogenetic analyses strongly suggest that the European epidemic CA-MRSA lineage is derived from a PVL-positive MSSA ancestor from sub-Saharan Africa. Moreover, the tree topology suggests a single acquisition of both the SCCmec element and a plasmid encoding the fusidic acid resistance determinant. Four canonical SNPs distinguish the derived CA-MRSA lineage and include a nonsynonymous mutation in accessory gene regulator C (agrC). These changes were associated with a star-like expansion into Europe, the Middle East, and North Africa in the early 1990s, including multiple cases of cross-continent imports likely driven by human migrations. PMID:25161186

  14. Diversity of antimicrobial resistance and virulence genes in methicillin-resistant non-Staphylococcus aureus staphylococci from veal calves.

    PubMed

    Argudín, M Angeles; Vanderhaeghen, Wannes; Butaye, Patrick

    2015-04-01

    In this study we determined whether methicillin-resistant non-Staphylococcus aureus (MRNAS) from veal calves may be a potential reservoir of antimicrobial-resistance and virulence genes. Fifty-eight MRNAS were studied by means of DNA-microarray and PCR for detection of antimicrobial resistance and virulence genes. The isolates carried a variety of antimicrobial-resistance genes [aacA-aphD, aadD, aph3, aadE, sat, spc, ampA, erm(A), erm(B), erm(C), erm(F), erm(T), lnu(A), msr(A)-msr(B), vga(A), mph(C), tet(K), tet(M), tet(L), cat, fexA, dfrA, dfrD, dfrG, dfrK, cfr, fusB, fosB, qacA, qacC, merA-merB]. Some isolates carried resistance genes without showing the corresponding resistance phenotype. Most MRNAS carried typical S. aureus virulence factors like proteases (sspP) and enterotoxins (seg) genes. Most Staphylococcus epidermidis isolates carried the arginine catabolic element, and nearly 40% of the Staphylococcus sciuri isolates carried leukocidins, and/or fibronectin-binding protein genes. MRNAS were highly multi-resistant and represent an important reservoir of antimicrobial resistance and virulence genes.

  15. Bullous impetigo in children infected with methicillin-resistant Staphylococcus aureus alone or in combination with methicillin-susceptible S. aureus: analysis of genetic characteristics, including assessment of exfoliative toxin gene carriage.

    PubMed

    Shi, Da; Higuchi, Wataru; Takano, Tomomi; Saito, Kohei; Ozaki, Kyoko; Takano, Misao; Nitahara, Yoshiyuki; Yamamoto, Tatsuo

    2011-05-01

    Among bullous impetigo isolates, exfoliative toxin (ET) gene carriage was found in 61.5% of methicillin-resistant Staphylococcus aureus (MRSA) isolates versus 90.6% of methicillin-susceptible S. aureus (MSSA) isolates. MRSA-only cases were ETB or ETA positive, while MRSA/MSSA coinfection cases were ET negative for MRSA but ETA positive for MSSA. Collagen adhesin may facilitate some MRSA infections.

  16. Synergism between Medihoney and rifampicin against methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Müller, Patrick; Alber, Dagmar G; Turnbull, Lynne; Schlothauer, Ralf C; Carter, Dee A; Whitchurch, Cynthia B; Harry, Elizabeth J

    2013-01-01

    Skin and chronic wound infections caused by highly antibiotic resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) are an increasing and urgent health problem worldwide, particularly with sharp increases in obesity and diabetes. New Zealand manuka honey has potent broad-spectrum antimicrobial activity, has been shown to inhibit the growth of MRSA strains, and bacteria resistant to this honey have not been obtainable in the laboratory. Combinational treatment of chronic wounds with manuka honey and common antibiotics may offer a wide range of advantages including synergistic enhancement of the antibacterial activity, reduction of the effective dose of the antibiotic, and reduction of the risk of antibiotic resistance. The aim of this study was to investigate the effect of Medihoney in combination with the widely used antibiotic rifampicin on S. aureus. Using checkerboard microdilution assays, time-kill curve experiments and agar diffusion assays, we show a synergism between Medihoney and rifampicin against MRSA and clinical isolates of S. aureus. Furthermore, the Medihoney/rifampicin combination stopped the appearance of rifampicin-resistant S. aureus in vitro. Methylglyoxal (MGO), believed to be the major antibacterial compound in manuka honey, did not act synergistically with rifampicin and is therefore not the sole factor responsible for the synergistic effect of manuka honey with rifampicin. Our findings support the idea that a combination of honey and antibiotics may be an effective new antimicrobial therapy for chronic wound infections. PMID:23469049

  17. First Record of Isolation and Characterization of Methicillin Resistant Staphylococcus lugdunensis from Clinical Samples in Iraq

    PubMed Central

    Al-Charrakh, Alaa H.; Obayes, Mohammed H.

    2014-01-01

    This study was conducted to determine the frequency of Staphylococcus lugdunensis in different clinical samples. Out of 690 clinical samples, a total of 178 coagulase negative staphylococci (CoNS) isolates were recovered. CoNS were identified as 10 different species; 22 isolates belonged to Staphylococcus lugdunensis. Two specific genes for S. lugdunensis were used ( tanA gene and fbl gene) to confirm identification. Both of these specific genes were detected in 15 (68.1%) of 22 isolates that were identified phenotypically. The results of oxacillin MIC showed that 7 of the 15 (46.6%) S. lugdunensis isolates were oxacillin resistant. The antibiotic susceptibility testing against 16 antibiotics showed that resistance rates were variable towards these antibiotics. Eight of fifteen S. lugdunensis isolates (53.3%) were β-lactamase producer. Results of molecular detection of mecA gene found that mecA gene was detected in 6 (40%) of 15 S. lugdunensis. All of these 6 isolates (S1, S2, S3, S4, S5, and S6) were resistant to oxacillin. One isolate (S7) was resistant to oxacillin but mecA was not detected in this isolate. This study is a first record of isolation and characterization of methicillin resistant S. lugdunensis (MRSL) from clinical samples in Iraq. PMID:25126573

  18. In Vitro Antibacterial and Antibiotic Resistance Modifying Effect of Bioactive Plant Extracts on Methicillin-Resistant Staphylococcus epidermidis.

    PubMed

    Chovanová, Romana; Mikulášová, Mária; Vaverková, Stefánia

    2013-01-01

    The crude extracts of plants from Asteraceae and Lamiaceae family and essential oils from Salvia officinalis and Salvia sclarea were studied for their antibacterial as well as antibiotic resistance modifying activity. Using disc diffusion and broth microdilution assays we determined higher antibacterial effect of three Salvia spp. and by evaluating the leakage of 260 nm absorbing material we detected effect of extracts and, namely, of essential oils on the disruption of cytoplasmic membrane. The evaluation of in vitro interactions between plant extracts and oxacillin described in terms of fractional inhibitory concentration (FIC) indices revealed synergistic or additive effects of plant extracts and clearly synergistic effects of essential oil from Salvia officinalis with oxacillin in methicillin-resistant Staphylococcus epidermidis. PMID:24222768

  19. Efficacy of clarithromycin on biofilm formation of methicillin-resistant Staphylococcus pseudintermedius

    PubMed Central

    2012-01-01

    Background Surgical site infections (SSIs) caused by biofilm-forming methicillin-resistant Staphylococcus pseudintermedius (MRSP) have emerged as the most common hospital-acquired infections in companion animals. No methods currently exist for the therapeutic remediation of SSIs caused by MRSP in biofilms. Clarithromycin (CLA) has been shown to prevent biofilm formation by Staphylococcus aureus. This study aims to assess the in vitro activity of CLA in eradicating MRSP biofilm formation on various materials. Results Quantitative assay results (P = 0.5126) suggest that CLA does not eradicate MRSP biofilm formation on polystyrene after 4 – 24 h growth periods. Scanning electron micrographs confirmed that CLA did not eradicate MRSP biofilm formed on orthopaedic implants. Conclusions By determining the in vitro characteristics and activities of MRSP isolates alone and against antibiotics, in vitro models of biofilm related infections can be made. In vitro data suggests that CLA does not effectively eradicate S. pseudintermedius biofilms in therapeutic doses. PMID:23171620

  20. [Guidelines for the treatment on infections caused by methicillin-resistant Staphylococcus aureus].

    PubMed

    Mensa, J; Barberán, J; Llinares, P; Picazo, Jj; Bouza, E; Alvarez-Lerma, F; Borges, M; Serrano, R; León, C; Guirao, X; Arias, J; Carreras, E; Sanz, Ma; García-Rodríguez, Ja

    2008-12-01

    Infections due to methicillin-resistant Staphylococcus aureus (MRSA) have undergone important changes in the last five years that have influenced the choice of therapy: i) increase of their frequency in hospital-associated settings and, more recently, in community settings; ii) better knowledge of clinical implications of the pharmacokinetic and pharmacodynamic properties of vancomycin; iii) improvement of current standard methods for rapid detection of MRSA in clinical samples; iv) clear evidence that vancomycin is losing efficacy against MRSA with MIC > 1 microg/mL; and v) appearance of new antibiotics suitable for use in these infections (linezolid, daptomycin, tigecyclin). Under this situation guidelines for the treatment of common infections caused by MRSA appear to be necessary to improve the efficacy and reduce the mortality.

  1. Deferoxamine mesylate enhances virulence of community-associated methicillin resistant Staphylococcus aureus.

    PubMed

    Arifin, Andrew J; Hannauer, Mélissa; Welch, Ian; Heinrichs, David E

    2014-11-01

    Staphylococcus aureus is a leading cause of bacterial infections. Strains of community-associated methicillin-resistant S. aureus (CA-MRSA), such as USA300, display enhanced virulence and fitness. Patients suffering from iron overload diseases often undergo iron chelation therapy with deferoxamine mesylate (DFO). Here, we show that USA300 uses this drug to acquire iron. We further demonstrate that mice administered DFO I.P., versus those not administered DFO, had significantly higher bacterial burden in livers and kidneys after I.V. challenge with USA300, associated with increased abscess formation and tissue destruction. The virulence of USA300 mutants defective for DFO uptake was not affected by DFO treatment.

  2. Methicillin-resistant Staphylococcus aureus (MRSA): a community-based prevalence survey.

    PubMed Central

    Abudu, L.; Blair, I.; Fraise, A.; Cheng, K. K.

    2001-01-01

    A prevalence survey of nasal methicillin-resistant Staphylococcus aureus (MRSA) carriage was undertaken on a random sample of adults (aged over 16) resident in the community in Birmingham, UK during 1998. Microbiological samples were taken from the anterior nares at the subjects' general practice or in their home. Information about risk factors for the acquisition of MRSA was obtained via a self-completed questionnaire. A 58% response rate (280/483) was achieved. The prevalence of nasal MRSA colonization was 1.5% [4/274, 95% confidence interval (CI) 0.03-2.9%]. Twenty-three per cent (63/274) of subjects were nasal carriers of S. aureus. Six per cent (4/63) of S. aureus isolates were MRSA and 2 of the 4 MRSA carriers reported previous contact with health facilities. The prevalence of MRSA colonization in the general adult population in Birmingham appears to be low. PMID:11467791

  3. Evaluation of weekly bathing in allergic dogs with methicillin-resistant Staphylococcal colonization.

    PubMed

    Kawarai, Shinpei; Fujimoto, Ayumi; Nozawa, Genta; Kanemaki, Nobuyuki; Madarame, Hiroo; Shida, Takuo; Kiuchi, Akio

    2016-05-01

    We evaluated the efficacy of weekly bathing in reducing methicillin-resistant Staphylococcus (MRS) colonization in canine allergic dermatitis in a pilot clinical trial. Six dogs with allergic dermatitis controlled by prescription medications were treated with weekly bathing for 1 month. The Canine Atopic Dermatitis Extent and Severity Index version 3 (CADESI-03) and pruritus scores and frequency of mecA-positive Staphylococcus spp. isolated from three body sites between weeks 0 and 4 were compared. There was no significant difference in CADESI-03 scores with bathing, whereas the pruritus scores were significantly reduced (p < 0.05). Furthermore, MRS frequency was decreased in four of the six dogs (p < 0.05). In conclusion, weekly bathing should be considered for reducing MRS colonization in canine allergic dermatitis. PMID:27506090

  4. Enteral vancomycin and probiotic use for methicillin-resistant Staphylococcus aureus antibiotic-associated diarrhoea.

    PubMed

    Sizemore, Elizabeth Nicole; Rivas, Kenya Maria; Valdes, Jose; Caballero, Joshua

    2012-07-27

    A geriatric patient status post intraabdominal surgery presented with persistent diarrhoea and heavy intestinal methicillin-resistant Staphylococcus aureus (MRSA) growth after multiple courses of antibiotic therapy. Additionally, swab cultures of the anterior nares tested positive for MRSA. In order to impede infection and prevent future complications, the patient received a 10-day course of vancomycin oral solution 250 mg every 6 h, 15-day course of Saccharomyces boulardii 250 mg orally twice daily and a 5-day course of topical mupirocin 2% twice daily intranasally. Diarrhoea ceased during therapy and repeat cultures 11 days after initiating therapy demonstrated negative MRSA growth from the stool and nares. Further repeat cultures 5 months later revealed negative MRSA growth in the stools and minimal MRSA growth in the nares. Overall, enteral vancomycin and probiotics successfully eradicated MRSA infection without intestinal recurrence. Although the results were beneficial treating MRSA diarrhoea for our patient, these agents remain highly controversial.

  5. Community-associated methicillin-resistant Staphylococcus aureus in college residential halls.

    PubMed

    Tonn, Katelynn; Ryan, Timothy J

    2013-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) was once a predominantly hospital-acquired organism but community-associated MRSA (CA-MRSA) has become a concern in athletics, prisons, and other nonclinical closed populations. As such, college residential hall occupants and workers may be at elevated risk of spreading or contracting MRSA. Environmental samples were obtained to identify the occurrence of MRSA on surfaces in bathrooms of 15 university residential halls. Sterile swabs and BBL CHROMagar plates were used to sample seven categories of potentially contaminated surfaces in each location. Frequencies and descriptive statistics were prepared. All sites had at least one positive sample for MRSA, and shower floors displayed the greatest prevalence (50%). These results indicate areas for heightened sanitation, and illustrate CA-MRSA potential from such surfaces. The need for hygiene education of affected persons about skin and soft tissue infections like MRSA, and intervention opportunities for public health professionals, are discussed.

  6. Prevalence of community-associated methicillin-resistant Staphylococcus aureus in high school wrestling environments.

    PubMed

    Stanforth, Bethany; Krause, Andrew; Starkey, Chad; Ryan, Timothy J

    2010-01-01

    Methicillin-resistant Staphylococcus Aureus (MRSA) was predominantly a hospital-acquired organism; recently, however, community-associated MRSA (CA-MRSA) has been causing outbreaks in otherwise healthy individuals involved in athletics. As such, CA-MRSA is of emerging concern to sanitarians and public health officials. Secondary school athletic trainers and student athletes may be at elevated risk of spreading or contracting MRSA. The absence of proper hygiene protocols or equipment may further increase this risk. In the study discussed in this article, environmental samples were obtained to identify the prevalence of MRSA on surfaces in high school athletic training and wrestling facilities mats in nine rural Ohio high schools. Frequencies and descriptive statistics were prepared. All nine (100%) of the sites tested had at least one positive sample for the presence of MRSA. The need for heightened sanitation, hygiene education of affected persons about skin and soft tissue infections like MRSA, and intervention opportunities for public health professionals are discussed.

  7. Complication of an Ahmed glaucoma valve implant: tube exposure with methicillin-resistant Staphylococcus aureus infection

    PubMed Central

    Pansegrau, Morgan L.; Mengarelli, Eddie; Dersu, Inci Irak

    2015-01-01

    Summary Neovascular glaucoma is commonly treated surgically with implantation of glaucoma drainage devices. We report the case of a 57-year-old man who underwent an uneventful Ahmed glaucoma valve (AGV) placement for radiation-induced neovascular glaucoma but later developed early postoperative infection with tube exposure. The infection was identified 3 weeks postoperatively and antibiotic treatment was immediately initiated. However, the conjunctival melt progressed, and the AGV had to be removed. Culture of the device revealed methicillin-resistant Staphylococcus aureus (MRSA). There is a potential increased risk of postoperative infection and tube exposure following glaucoma valve implantation in patients with previous radiation therapy. To our knowledge, this is the second case in the literature of MRSA causing early postoperative infection following drainage device placement that required explantation. PMID:27330471

  8. Complication of an Ahmed glaucoma valve implant: tube exposure with methicillin-resistant Staphylococcus aureus infection.

    PubMed

    Pansegrau, Morgan L; Mengarelli, Eddie; Dersu, Inci Irak

    2015-01-01

    Neovascular glaucoma is commonly treated surgically with implantation of glaucoma drainage devices. We report the case of a 57-year-old man who underwent an uneventful Ahmed glaucoma valve (AGV) placement for radiation-induced neovascular glaucoma but later developed early postoperative infection with tube exposure. The infection was identified 3 weeks postoperatively and antibiotic treatment was immediately initiated. However, the conjunctival melt progressed, and the AGV had to be removed. Culture of the device revealed methicillin-resistant Staphylococcus aureus (MRSA). There is a potential increased risk of postoperative infection and tube exposure following glaucoma valve implantation in patients with previous radiation therapy. To our knowledge, this is the second case in the literature of MRSA causing early postoperative infection following drainage device placement that required explantation.

  9. Distribution of genes encoding aminoglycoside-modifying enzymes among clinical isolates of methicillin-resistant staphylococci.

    PubMed

    Perumal, N; Murugesan, S; Krishnan, P

    2016-01-01

    The objective of this study was to determine the distribution of genes encoding aminoglycoside-modifying enzymes (AMEs) and staphylococcal cassette chromosome mec (SCCmec) elements among clinical isolates of methicillin-resistant staphylococci (MRS). Antibiotic susceptibility test was done using Kirby-Bauer disk diffusion method. The presence of SCCmec types and AME genes, namely, aac (6')-Ie-aph (2''), aph (3')-IIIa and ant (4')-Ia was determined using two different multiplex polymerase chain reaction. The most encountered AME genes were aac (6')-Ie-aph (2'') (55.4%) followed by aph (3')-IIIa (32.3%) and ant (4')-Ia gene (9%). SCCmec type I (34%) was predominant in this study. In conclusion, the aac (6')-Ie-aph (2'') was the most common AME gene and SCCmec type I was most predominant among the MRS isolates. PMID:27514959

  10. Cytotoxic Virulence Predicts Mortality in Nosocomial Pneumonia Due to Methicillin-Resistant Staphylococcus aureus.

    PubMed

    Rose, Hannah R; Holzman, Robert S; Altman, Deena R; Smyth, Davida S; Wasserman, Gregory A; Kafer, Jared M; Wible, Michelle; Mendes, Rodrigo E; Torres, Victor J; Shopsin, Bo

    2015-06-15

    The current study identified bacterial factors that may improve management of methicillin-resistant Staphylococcus aureus (MRSA) nosocomial pneumonia. Isolates were obtained from 386 patients enrolled in a randomized, controlled study of antibiotic efficacy. Isolates were screened for production of virulence factors and for vancomycin susceptibility. After adjustment for host factors such as severity of illness and treatment modality, cytotoxic activity was strongly and inversely associated with mortality; however, it had no effect on clinical cure. Isolates having low cytotoxicity, which were derived largely from healthcare-associated clones, exhibited a greater prevalence of vancomycin heteroresistance, and they were recovered more often from patients who were older and frailer. Additionally, a clone with low cytotoxic activity was associated with death and poor clinical improvement. Clone specificity and attenuated virulence appear to be associated with outcome. To our knowledge, these are the first correlations between MRSA virulence and mortality in nosocomial pneumonia.

  11. Marinopyrrole Derivatives as Potential Antibiotic Agents against Methicillin-Resistant Staphylococcus aureus (III)

    PubMed Central

    Liu, Yan; Haste, Nina M.; Thienphrapa, Wdee; Li, Jerry; Nizet, Victor; Hensler, Mary; Li, Rongshi

    2014-01-01

    The marine natural product, marinopyrrole A (1), was previously shown to have significant antibiotic activity against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). Although compound (1) exhibits a significant reduction in MRSA activity in the presence of human serum, we have identified key modifications that partially restore activity. We previously reported our discovery of a chloro-derivative of marinopyrrole A (1a) featuring a 2–4 fold improved minimum inhibitory concentration (MIC) against MRSA, significantly less susceptibility to serum inhibition and rapid and concentration-dependent killing of MRSA. Here, we report a novel fluoro-derivative of marinopyrrole A (1e) showing an improved profile of potency, less susceptibility to serum inhibition, as well as rapid and concentration-dependent killing of MRSA. PMID:24796304

  12. Surface plasmon resonance detection of E. coli and methicillin-resistant S. aureus using bacteriophages.

    PubMed

    Tawil, Nancy; Sacher, Edward; Mandeville, Rosemonde; Meunier, Michel

    2012-01-01

    Early diagnosis and appropriate treatment of Escherichia coli (E. coli) O157:H7 and methicillin-resistant Staphylococcus aureus (MRSA) are key elements in preventing resultant life-threatening illnesses, such as hemorrhagic colitis, hemolytic uremic syndrome, and septicemia. In this report, we describe the use of surface plasmon resonance (SPR) for the biodetection of pathogenic bacteria, using bacteriophages as the recognition elements. T4 bacteriophages were used to detect E. coli, while a novel, highly specific phage was used to detect MRSA. We found that the system permits label-free, real-time, specific, rapid and cost-effective detection of pathogens, for concentrations of 10(3) colony forming units/milliliter, in less than 20 min. This system promises to become a diagnostic tool for bacteria that cause major public concern for food safety, bioterrorism, and nosocomial infections.

  13. Cytotoxic Virulence Predicts Mortality in Nosocomial Pneumonia Due to Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Rose, Hannah R.; Holzman, Robert S.; Altman, Deena R.; Smyth, Davida S.; Wasserman, Gregory A.; Kafer, Jared M.; Wible, Michelle; Mendes, Rodrigo E.; Torres, Victor J.; Shopsin, Bo

    2015-01-01

    The current study identified bacterial factors that may improve management of methicillin-resistant Staphylococcus aureus (MRSA) nosocomial pneumonia. Isolates were obtained from 386 patients enrolled in a randomized, controlled study of antibiotic efficacy. Isolates were screened for production of virulence factors and for vancomycin susceptibility. After adjustment for host factors such as severity of illness and treatment modality, cytotoxic activity was strongly and inversely associated with mortality; however, it had no effect on clinical cure. Isolates having low cytotoxicity, which were derived largely from healthcare-associated clones, exhibited a greater prevalence of vancomycin heteroresistance, and they were recovered more often from patients who were older and frailer. Additionally, a clone with low cytotoxic activity was associated with death and poor clinical improvement. Clone specificity and attenuated virulence appear to be associated with outcome. To our knowledge, these are the first correlations between MRSA virulence and mortality in nosocomial pneumonia. PMID:25298028

  14. [Treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections in Latin America].

    PubMed

    Luna, Carlos M; Rodríguez-Noriega, Eduardo; Bavestrello, Luis; Gotuzzo, Eduardo

    2010-08-01

    The global spread of MRSA means it is now a pathogen of worldwide public health concern. Within Latin America, MRSA is highly prevalent, with the proportion of S. aureus isolates that are methicillin-resistant on the rise, yet resources for managing the infection are limited. While several guidelines exist for the treatment of MRSA infections, many are written for the North American or European setting and need adaptation for use in Latin America. In this article, we aim to emphasize the importance of appropriate treatment of MRSA in the healthcare and community settings of Latin America. We present a summary of the available guidelines and antibiotics, and discuss particular considerations for clinicians treating MRSA in Latin America. PMID:21137164

  15. [Treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections in Latin America].

    PubMed

    Luna, Carlos M; Rodríguez-Noriega, Eduardo; Bavestrello, Luis; Gotuzzo, Eduardo

    2010-08-01

    The global spread of MRSA means it is now a pathogen of worldwide public health concern. Within Latin America, MRSA is highly prevalent, with the proportion of S. aureus isolates that are methicillin-resistant on the rise, yet resources for managing the infection are limited. While several guidelines exist for the treatment of MRSA infections, many are written for the North American or European setting and need adaptation for use in Latin America. In this article, we aim to emphasize the importance of appropriate treatment of MRSA in the healthcare and community settings of Latin America. We present a summary of the available guidelines and antibiotics, and discuss particular considerations for clinicians treating MRSA in Latin America.

  16. Methicillin-resistant Staphylococcus aureus ulcerative keratitis in a Thoroughbred racehorse

    PubMed Central

    KURODA, Taisuke; KINOSHITA, Yuta; NIWA, Hidekazu; MIZOBE, Fumiaki; UENO, Takanori; KUWANO, Atsutoshi; HATAZOE, Takashi; HOBO, Seiji

    2015-01-01

    ABSTRACT We report the first case of methicillin-resistant Staphylococcus aureus (MRSA) keratitis in a racehorse. A 5-year-old mare developed punctate keratitis after racing. The corneal ulcer continued to expand despite ophthalmic antimicrobial therapy. On day 6, a conjunctival graft surgery was performed. The mare was euthanized, following colitis and laminitis development on day 10. MRSA was isolated from the corneal swab taken at the time of euthanasia. Immunohistochemical analysis demonstrated gram-positive and anti-S. aureus monoclonal antibody-positive cocci infiltration of the corneal stroma; and a diagnosis of MRSA ulcerative keratitis was made. An ophthalmic antimicrobial against the isolated MRSA did not improve the ocular lesion. The MRSA strain was found to be staphylococcal cassette chromosome mec type II, a strain frequently isolated from humans in Japan. PMID:26435683

  17. Methicillin-resistant Staphylococcus aureus ulcerative keratitis in a Thoroughbred racehorse.

    PubMed

    Kuroda, Taisuke; Kinoshita, Yuta; Niwa, Hidekazu; Mizobe, Fumiaki; Ueno, Takanori; Kuwano, Atsutoshi; Hatazoe, Takashi; Hobo, Seiji

    2015-01-01

    We report the first case of methicillin-resistant Staphylococcus aureus (MRSA) keratitis in a racehorse. A 5-year-old mare developed punctate keratitis after racing. The corneal ulcer continued to expand despite ophthalmic antimicrobial therapy. On day 6, a conjunctival graft surgery was performed. The mare was euthanized, following colitis and laminitis development on day 10. MRSA was isolated from the corneal swab taken at the time of euthanasia. Immunohistochemical analysis demonstrated gram-positive and anti-S. aureus monoclonal antibody-positive cocci infiltration of the corneal stroma; and a diagnosis of MRSA ulcerative keratitis was made. An ophthalmic antimicrobial against the isolated MRSA did not improve the ocular lesion. The MRSA strain was found to be staphylococcal cassette chromosome mec type II, a strain frequently isolated from humans in Japan. PMID:26435683

  18. Nosocomial keratitis caused by methicillin-resistant Staphylococcus aureus: case report and preventative measures

    PubMed Central

    Braich, Puneet S.; Aggarwal, Shruti; Mukhtar, Sabrina; Almeida, David RP.

    2015-01-01

    A 47-year-old African-American woman was admitted to the intensive care unit of our community hospital for respiratory failure secondary to severe decompensated heart failure, requiring intubation. In the ensuing days, she developed a methicillin-resistant Staphylococcus aureus (MRSA) infection of the cornea, despite no growth of MRSA in multiple blood, sputum, and urine cultures. This unexpected corneal infection complicated her hospital stay, and increased morbidity and disease-related cost. Risk factors, warning signs, and preventative measures for MRSA keratitis secondary to lagophthalmos (inability to completely close one's eyelids) are outlined in this case report. Implementing simple precautions such as taping eyelids shut or using artificial lubrication may reduce patient morbidity and disease-related costs. These recommendations are directed to non-ophthalmic clinicians who provide care to patients in settings where MRSA colonization is widespread. PMID:26486112

  19. Marinopyrrole derivatives as potential antibiotic agents against methicillin-resistant Staphylococcus aureus (III).

    PubMed

    Liu, Yan; Haste, Nina M; Thienphrapa, Wdee; Li, Jerry; Nizet, Victor; Hensler, Mary; Li, Rongshi

    2014-04-30

    The marine natural product, marinopyrrole A (1), was previously shown to have significant antibiotic activity against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). Although compound (1) exhibits a significant reduction in MRSA activity in the presence of human serum, we have identified key modifications that partially restore activity. We previously reported our discovery of a chloro-derivative of marinopyrrole A (1a) featuring a 2-4 fold improved minimum inhibitory concentration (MIC) against MRSA, significantly less susceptibility to serum inhibition and rapid and concentration-dependent killing of MRSA. Here, we report a novel fluoro-derivative of marinopyrrole A (1e) showing an improved profile of potency, less susceptibility to serum inhibition, as well as rapid and concentration-dependent killing of MRSA.

  20. A Fatal Case of Eczema Herpeticum With Septic Shock Due to Methicillin-Resistant Staphylococcus aureus.

    PubMed

    Tupe, Christina L; Weiler, Bethany A; Verceles, Avelino C; McCurdy, Michael T

    2016-07-01

    A 62-year-old woman treated with several courses of corticosteroids for an undifferentiated rash came to the emergency department with progressively worsening cutaneous signs and symptoms and generalized weakness. She had scabies, and despite treatment continued to decompensate. Repeat skin biopsies revealed disseminated herpes simplex virus infection, and results of blood cultures were consistent with infection by methicillin-resistant Staphylococcus aureus. Despite antiviral and antimicrobial therapy, sepsis and multiorgan failure developed, and the patient died. This case illustrates the complications of the rare entity eczema herpeticum, which occurs most often in immunocompromised patients and is associated with a high mortality. Maintaining a high index of suspicion for this disease in decompensating patients with an unidentified rash is essential to avoid catastrophic outcomes. PMID:27369040

  1. Global epidemiology of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA).

    PubMed

    Mediavilla, José R; Chen, Liang; Mathema, Barun; Kreiswirth, Barry N

    2012-10-01

    During the 1990s, various reports of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections appeared in the literature, caused by novel strains genetically distinct from traditional healthcare-associated MRSA (HA-MRSA). Numerous lineages of CA-MRSA have since emerged on every continent, several of which have spread internationally, most notably USA300. CA-MRSA strains are increasingly implicated in nosocomial infections, and may eventually displace HA-MRSA strains in hospitals. Consequently, distinctions based on clinical epidemiology and susceptibility are becoming less relevant, arguing in favor of genotypic definitions. We review the current molecular epidemiology of CA-MRSA with respect to genetic diversity, global distribution, and factors related to its emergence and spread.

  2. Bactericidal Kinetics of Marine-Derived Napyradiomycins against Contemporary Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Haste, Nina M.; Farnaes, Lauge; Perera, Varahenage R.; Fenical, William; Nizet, Victor; Hensler, Mary E.

    2011-01-01

    There is an urgent need for new antibiotics to treat hospital- and community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections. Previous work has indicated that both terrestrial and marine-derived members of the napyradiomycin class possess potential anti-staphylococcal activities. These compounds are unique meroterpenoids with unusual levels of halogenation. In this paper we report the evaluation of two previously described napyradiomycin derivatives, A80915A (1) and A80915B (2) produced by the marine-derived actinomycete, Streptomyces sp. strain CNQ-525, for their specific activities against contemporary and clinically relevant MRSA. Reported are studies of the in vitro kinetics of these chemical scaffolds in time-kill MRSA assays. Both napyradiomycin derivatives demonstrate potent and rapid bactericidal activity against contemporary MRSA strains. These data may help guide future development and design of analogs of the napyradiomycins that could potentially serve as useful anti-MRSA therapeutics. PMID:21731557

  3. Postoperative infection of an abdominal mesh due to methicillin resistant Staphylococcus aureus - a case report.

    PubMed

    Ashok, R; Anuradha, K; Babu, S S; Bheerappa, N; Sastry, R A; Lakshmi, V

    2004-01-01

    Methicillin resistant Stephylococcus aureus (MRSA) infection has now become a major problem in hospitals. We present a case of postoperative infection MRSA where the primary source of the infection was found to be an abdominal mesh that was used to reinforce the abdominal wall. After one year of surgery, the patient developed wound dehiscence and discharge. MRSA was isolated from the wound, mesh, external nares, throat and axilla. Initially she was started on clindamycin and discharged from the hospital. After 5 months, patient came back to the hospital with infection at the same site. The patient was then treated with vancomycin and MRSA clearance. She responded to the treatment with complete healing of the wound and clearance of MRSA.

  4. Biofilm formation on tympanostomy tubes depends on methicillin-resistant Staphylococcus aureus genetic lineage.

    PubMed

    Jotić, Ana; Božić, Dragana D; Milovanović, Jovica; Pavlović, Bojan; Ješić, Snežana; Pelemiš, Mijomir; Novaković, Marko; Ćirković, Ivana

    2016-03-01

    Bacterial biofilm formation has been implicated in the high incidence of persistent otorrhoea after tympanostomy tube insertion. The aim of the study was to investigate whether biofilm formation on tympanostomy tubes depends on the genetic profile of methicillin-resistant Staphylococcus aureus (MRSA) strains. Capacity of biofilm formation on fluoroplastic tympanostomy tubes (TTs) was tested on 30 MRSA strains. Identification and methicillin resistance were confirmed by PCR for nuc and mecA genes. Strains were genotypically characterised (SCCmec, agr and spa typing). Biofilm formation was tested in microtiter plate and on TTs. Tested MRSA strains were classified into SCCmec type I (36.7 %), III (23.3 %), IV (26.7 %) and V (13.3 %), agr type I (50 %), II (36.7 %) and III (13.3 %), and 5 clonal complexes (CCs). All tested MRSA strains showed ability to form biofilm on microtiter plate. Capacity of biofilm formation on TTs was as following: 13.3 % of strains belonged to the category of no biofilm producers, 50 % to the category of weak biofilm producers and 36.7 % to moderate biofilm producers. There was a statistically significant difference between CC, SCCmec and agr types and the category of biofilm production on TTs tubes (p < 0.001): CC5, SCCmecI type and agrII type with a moderate amount of biofilm, and CC8 and agrI type with a low amount of biofilm. Biofilm formation by MRSA on TTs is highly dependent on genetic characteristics of the strains. Therefore, MRSA genotyping may aid the determination of the possibility of biofilm-related post-tympanostomy tube otorrhea.

  5. Methicillin-resistant Staphylococcus aureus nosocomial pneumonia: role of linezolid in the People's Republic of China.

    PubMed

    Lesher, Beth; Gao, Xin; Chen, Yixi; Liu, Zhengyin

    2016-01-01

    The burden of methicillin-resistant Staphylococcus aureus (MRSA) nosocomial pneumonia in the People's Republic of China is high, with methicillin-resistance rates greater than 80% reported for patients with S. aureus pneumonia treated in intensive care units. Historically, vancomycin was the treatment of choice for patients with hospital-acquired MRSA infections. Recent evidence suggests that the minimum inhibitory concentration for vancomycin is increasing. Additionally, patients treated with vancomycin require monitoring of vancomycin trough concentrations and can develop nephrotoxicity. Linezolid is a treatment option for patients with hospital-acquired MRSA infections that can be administered either intravenously or orally. Analysis of data from a worldwide linezolid surveillance program initiated in the year 2004 shows no evidence of increasing linezolid minimum inhibitory concentrations. The clinical efficacy of linezolid for patients with gram-positive, including MRSA, nosocomial pneumonia, was evaluated in numerous studies. In general, results from these studies show higher or similar clinical success with no mortality difference for linezolid compared to vancomycin treated patients. Results from a Phase IV study enrolling patients with MRSA-confirmed nosocomial pneumonia suggest higher clinical cure rates for linezolid compared to vancomycin treated patients. Although acquisition costs are higher for linezolid compared to vancomycin therapy, evidence suggests similar overall medical costs. Cost-analysis results from a Chinese perspective show that linezolid dominated vancomycin therapy for MRSA nosocomial pneumonia in ∼35% of bootstrap simulations whereas vancomycin dominated linezolid in less than 2% of bootstrap simulations. In summary, results from both clinical and economic studies, including studies conducted from a Chinese perspective, support the use of linezolid for the treatment of patients with MRSA nosocomial pneumonia. PMID:27069370

  6. Enhanced adherence of methicillin-resistant Staphylococcus pseudintermedius sequence type 71 to canine and human corneocytes

    PubMed Central

    2014-01-01

    The recent worldwide spread of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in dogs is a reason for concern due to the typical multidrug resistance patterns displayed by some MRSP lineages such as sequence type (ST) 71. The objective of this study was to compare the in vitro adherence properties between MRSP and methicillin-susceptible (MSSP) strains. Four MRSP, including a human and a canine strain belonging to ST71 and two canine non-ST71 strains, and three genetically unrelated MSSP were tested on corneocytes collected from five dogs and six humans. All strains were fully characterized with respect to genetic background and cell wall-anchored protein (CWAP) gene content. Seventy-seven strain-corneocyte combinations were tested using both exponential- and stationary-phase cultures. Negative binomial regression analysis of counts of bacterial cells adhering to corneocytes revealed that adherence was significantly influenced by host and strain genotype regardless of bacterial growth phase. The two MRSP ST71 strains showed greater adherence than MRSP non-ST71 (p < 0.0001) and MSSP (p < 0.0001). This phenotypic trait was not associated to any specific CWAP gene. In general, S. pseudintermedius adherence to canine corneocytes was significantly higher compared to human corneocytes (p < 0.0001), but the MRSP ST71 strain of human origin adhered equally well to canine and human corneocytes, suggesting that MRSP ST71 may be able to adapt to human skin. The genetic basis of the enhanced in vitro adherence of ST71 needs to be elucidated as this phenotypic trait may be associated to the epidemiological success and zoonotic potential of this epidemic MRSP clone. PMID:24957656

  7. [Molecular diagnosis of methicillin-resistent Staphylococcus aureus: Methods and efficacy].

    PubMed

    Hell, M; Bauer, J W; Laimer, M

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) isolates are a serious public health problem whose ever-increasing rate is commensurate with the pressure it is exerting on the healthcare system. At present, more than 20% of clinical S. aureus isolates in German hospitals are methicillin-resistant, in Austria less than 10%. Strategies from low-prevalence countries show that this development is not necessarily inevitable. In the Scandinavian countries and the Netherlands, thanks to a rigorous prevention programme, MRSA prevalence has been kept at an acceptably low level (< 1-3%). Central to these search-and-destroy control strategies is an admission screening using several MRSA swabs taken from mucocutaneous colonisation sites of high-risk patients (MRSA surveillance). It has also been reported that the speed with which MRSA carriage is detected has an important role, as it is a key component of any effective strategy to prevent the pathogen from spreading. Since MRSA culturing involves a 2-3 day delay before the final results are available, rapid detection techniques (commonly referred to as MRSA rapid tests) using polymerase chain reaction (PCR) methods and, most recently, rapid culturing methods have been developed. The implementation of rapid tests reduces the time of detection of MRSA carriers from 48-72 to 2-5 h. Clinical evaluation data have shown that MRSA can thus be detected with very high sensitivity. Specificity, however, is sometimes impaired due to false-positive PCR signals occurring in mixed flora specimens. In order to rule out false-positive PCR results, a culture screen must always be carried out simultaneously. The data provide preliminary evidence that a PCR assay can reduce nosocomial MRSA transmission in high-risk patients or high-risk areas, whereas an approach that screens all patients admitted to the hospital is probably not effective. Information concerning the cost effectiveness of rapid MRSA tests is still sparse and thus the issue

  8. Typing of Methicillin Resistant Staphylococcus Aureus Using DNA Fingerprints by Pulsed-field Gel Electrophoresis

    PubMed Central

    Rebic, Velma; Budimir, Ana; Aljicevic, Mufida; Bektas, Sabaheta; Vranic, Sabina Mahmutovic; Rebic, Damir

    2016-01-01

    Background: Methicillin resistant Staphylococcus aureus (MRSA) is responsible for a wide spectrum of nosocomial and community associated infections worldwide. The aim of this study was to analyze MRSA strains from the general population in Canton Sarajevo, B&H. Methods: Our investigation including either phenotypic and genotypic markers such as antimicrobial resistance, pulsed-field gel electrophoresis (PFGE), SCC typing, and Panton-Valentine leukocidin (PVL) detection. Results: Antimicrobial susceptibility: all MRSA isolates were resistant to the β-lactam antibiotics tested, and all isolates were susceptible trimethoprim sulphamethoxazole, rifampicin, fusidic acid, linezolid and vancomycin. Sixty-eight per cent of the MRSA isolates were resistant to erythromycin, 5% to clindamycin, 5% to gentamicin and 4% to ciprofloxacin. After the PFGE analysis, the isolates were grouped into five similarity groups: A-E. The largest number of isolates belonged to one of two groups: C: 60 (60%) and D: 27 (27%). In both groups C and D, SCCmec type IV was predominant (60% and 88, 8%, respectively). A total of 24% of the isolates had positive expression of PVL genes, while 76% showed a statistically significantly greater negative expression of PVL genes. Conclusion: SCCmec type IV, together with the susceptibility profile and PFGE grouping, is considered to be typical of CA-MRSA PMID:27708486

  9. Biochemical Fingerprinting of Methicillin-Resistant Staphylococcus aureus Isolated From Sewage and Hospital in Iran

    PubMed Central

    Rahimi, Fateh; Bouzari, Majid

    2015-01-01

    Background: Methicillin-resistant Staphylococcus aureus (MRSA) is known as a common pathogen in nosocomial and community-acquired infections. Sewage acts as an environmental reservoir and may have a significant role in development and dissemination of antibiotic resistance. Objectives: This study was undertaken to determine the epidemiological relatedness between the MRSA isolated from sewage and human infections. Materials and Methods: Samples were collected from a referral hospital and also a sewage treatment plant in Tehran, Iran, during 2010. All the MRSA isolates were identified at the species level and typed using Phene plate (PhP) system and SCCmec typing. Antibiotic susceptibility tests were also performed. Results: Of the 1142 isolates, 200 MRSA strains from the sewage (n = 100) and the clinic (n = 100) were isolated. Distinct PhP types, consisting of 16 common types and 13 single types, and also 3 different staphylococcal cassette chromosome mec (SCCmec) types (III, IVa and IVc) were found amongst the MRSA isolated from the two different sources. The results of antibiotic susceptibility testing showed an increased resistance to penicillin, ciprofloxacin, erythromycin, clindamycin and tetracycline. In addition, none of the isolates showed resistance to vancomycin, quinupristin -dalfopristin and linezolid. Conclusions: The presence of common PhP types and also SCCmec type III, as an indicator for hospital strains, among the isolates, may indicate an epidemiological link between clinical and sewage MRSA isolates in Tehran. PMID:26421131

  10. Antimicrobial activity of zinc and titanium dioxide nanoparticles against biofilm-producing methicillin-resistant Staphylococcus aureus

    NASA Astrophysics Data System (ADS)

    Jesline, A.; John, Neetu P.; Narayanan, P. M.; Vani, C.; Murugan, Sevanan

    2015-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major nosocomial pathogens responsible for a wide spectrum of infections and the emergence of bacterial resistance to antibiotics has lead to treatment drawbacks towards large number of drugs. Formation of biofilms is the main contributing factor to antibiotic resistance. The development of reliable processes for the synthesis of zinc oxide nanoparticles is an important aspect of nanotechnology today. Zinc oxide and titanium dioxide nanoparticles comprise well-known inhibitory and bactericidal effects. Emergence of antimicrobial resistance by pathogenic bacteria is a major health problem in recent years. This study was designed to determine the efficacy of zinc and titanium dioxide nanoparticles against biofilm producing methicillin-resistant S. aureus. Biofilm production was detected by tissue culture plate method. Out of 30 MRSA isolates, 22 isolates showed strong biofilm production and 2 showed weak and moderate biofilm formation. Two strong and weak biofilm-producing methicillin-resistant S. aureus isolates were subjected to antimicrobial activity using commercially available zinc and titanium dioxide nanoparticles. Thus, the nanoparticles showed considerably good activity against the isolates, and it can be concluded that they may act as promising, antibacterial agents in the coming years.

  11. Genotypic and phenotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) clones with high-level mupirocin resistance.

    PubMed

    González-Domínguez, María; Seral, Cristina; Potel, Carmen; Sáenz, Yolanda; Álvarez, Maximiliano; Torres, Carmen; Castillo, Francisco Javier

    2016-06-01

    A high proportion of methicillin-resistant Staphylococcus aureus isolates recovered in one year period showed high-level mupirocin-resistance (HLMUPR-MRSA) in our environment (27.2%). HLMUPR-MRSA isolates were mainly collected from skin and soft tissue samples, and diabetes was the main related comorbidity condition. These isolates were more frequently found in vascular surgery. HLMUPR-MRSA was more resistant to aminoglycosides than mupirocin-susceptible MRSA, linked to the presence of bifunctional and/or nucleotidyltransferase enzymes with/without macrolide resistance associated with the msr(A) gene. Most of HLMUPR-MRSA isolates belonged to ST125/t067. Nine IS257-ileS2 amplification patterns (p3 was the most frequent) were observed in HLMUPR-MRSA isolates, suggesting the presence of several mupirocin-resistance-carrying plasmids in our environment and promoting the emergence of mupirocin resistance. The presence of the same IS257-ileS2 amplification pattern p3 in 65% of HLMUPR-MRSA, all of them ST125/t067, suggests a clonal spread in our hospital and community environment which could explain the high prevalence of HLMUPR-MRSA during the study period. An outbreak situation or an increase in mupirocin consumption was not observed.

  12. Molecular characterization of methicillin-resistant Staphylococcus aureus resistant to tigecycline and daptomycin isolated in a hospital in Brazil.

    PubMed

    Dabul, A N G; Camargo, I L B C

    2014-03-01

    We report the molecular characterization of methicillin-resistant Staphylococcus aureus (MRSA) with resistance to tigecycline and to daptomycin isolated from intensive-care-unit patients in Brazil over a 6-month period. Thirty-six isolates (25 from infection sites, 11 from nasal sites) recovered from 23 patients who presented with MRSA infection during this period were characterized by pulsed-field gel electrophoresis, multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec) typing, and antimicrobial susceptibility profiling. Ten isolates from six patients and two isolates from different patients were resistant to tigecycline and daptomycin, respectively. Eight pulsotypes were identified and one, type A, accounted for 21 isolates from 12 patients; type A isolates were SCCmecII as were a further nine isolates of other pulsotypes. All but four of the total isolates were sequence type (ST) 5 or ST105 and classified as clonal complex (CC) 5; the historically prevalent lineage in Brazil, ST239-SCCmecIII, was identified in only three patients. Tigecycline-resistant strains were all ST105-SCCmecII and two patients were nasally colonized by strains of the same pulsotype found in infection sites. Two ST5-SCCmecII were daptomycin resistant after 48 h incubation. The origin and mechanism of these resistant strains remains unknown and further studies are warranted to determine whether such clones are becoming endemic in Brazilian hospitals and to assess their impact on infection control practice. PMID:23714160

  13. Spread of methicillin-resistant Staphylococcus aureus belonging to the Brazilian epidemic clone in a general hospital and emergence of heterogenous resistance to glycopeptide antibiotics among these isolates.

    PubMed

    dos Santos Soares, M J; da Silva-Carvalho, M C; Ferreira-Carvalho, B T; Figueiredo, A M

    2000-04-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections have been increasing at an alarming rate world-wide. MRSA epidemics due to the clonal spread of multi-resistant isolates have been described. In this paper we show the absolute predominance of MRSA strains from the Brazilian epidemic clone in a hospital in the Northeast region of Brazil and the emergence of a vancomycin and teicoplanin heterogeneous resistant subpopulation among these isolates.

  14. Reduced susceptibility to vancomycin and biofilm formation in methicillin-resistant Staphylococcus epidermidis isolated from blood cultures.

    PubMed

    Pinheiro, Luiza; Brito, Carla Ivo; Pereira, Valéria Cataneli; Oliveira, Adilson de; Camargo, Carlos Henrique; Cunha, Maria de Lourdes Ribeiro de Souza da

    2014-11-01

    This study aimed to correlate the presence of ica genes, biofilm formation and antimicrobial resistance in 107 strains of Staphylococcus epidermidis isolated from blood cultures. The isolates were analysed to determine their methicillin resistance, staphylococcal cassette chromosome mec (SCCmec) type, ica genes and biofilm formation and the vancomycin minimum inhibitory concentration (MIC) was measured for isolates and subpopulations growing on vancomycin screen agar. The mecA gene was detected in 81.3% of the S. epidermidis isolated and 48.2% carried SCCmec type III. The complete icaADBC operon was observed in 38.3% of the isolates; of these, 58.5% produced a biofilm. Furthermore, 47.7% of the isolates grew on vancomycin screen agar, with an increase in the MIC in 75.9% of the isolates. Determination of the MIC of subpopulations revealed that 64.7% had an MIC ≥ 4 μg mL-1, including 15.7% with an MIC of 8 μg mL-1 and 2% with an MIC of 16 μg mL-1. The presence of the icaADBC operon, biofilm production and reduced susceptibility to vancomycin were associated with methicillin resistance. This study reveals a high level of methicillin resistance, biofilm formation and reduced susceptibility to vancomycin in subpopulations of S. epidermidis. These findings may explain the selection of multidrug-resistant isolates in hospital settings and the consequent failure of antimicrobial treatment.

  15. Reduced susceptibility to vancomycin and biofilm formation in methicillin-resistant Staphylococcus epidermidis isolated from blood cultures.

    PubMed

    Pinheiro, Luiza; Brito, Carla Ivo; Pereira, Valéria Cataneli; Oliveira, Adilson de; Camargo, Carlos Henrique; Cunha, Maria de Lourdes Ribeiro de Souza da

    2014-11-01

    This study aimed to correlate the presence of ica genes, biofilm formation and antimicrobial resistance in 107 strains of Staphylococcus epidermidis isolated from blood cultures. The isolates were analysed to determine their methicillin resistance, staphylococcal cassette chromosome mec (SCCmec) type, ica genes and biofilm formation and the vancomycin minimum inhibitory concentration (MIC) was measured for isolates and subpopulations growing on vancomycin screen agar. The mecA gene was detected in 81.3% of the S. epidermidis isolated and 48.2% carried SCCmec type III. The complete icaADBC operon was observed in 38.3% of the isolates; of these, 58.5% produced a biofilm. Furthermore, 47.7% of the isolates grew on vancomycin screen agar, with an increase in the MIC in 75.9% of the isolates. Determination of the MIC of subpopulations revealed that 64.7% had an MIC ≥ 4 μg mL-1, including 15.7% with an MIC of 8 μg mL-1 and 2% with an MIC of 16 μg mL-1. The presence of the icaADBC operon, biofilm production and reduced susceptibility to vancomycin were associated with methicillin resistance. This study reveals a high level of methicillin resistance, biofilm formation and reduced susceptibility to vancomycin in subpopulations of S. epidermidis. These findings may explain the selection of multidrug-resistant isolates in hospital settings and the consequent failure of antimicrobial treatment. PMID:25410990

  16. Molecular epidemiology of methicillin-resistant Staphylococcus aureus in Colombian hospitals: dominance of a single unique multidrug-resistant clone.

    PubMed

    Gomes, A R; Sanches, I S; Aires de Sousa, M; Castañeda, E; de Lencastre, H

    2001-01-01

    The first study on the molecular characterization of methicillin-resistant Staphylococcus aureus (MRSA) isolates from Colombia was performed as part of a global surveillance established by the CEM/NET Initiative, under Project RESIST. Seventy-six MRSA isolates recovered from five hospitals during 1996-1998 were analyzed by the hybridization of ClaI restriction digests with mecA- and Tn554-specific probes, and by pulsed-field gel electrophoresis (PFGE) of chromosomal SmaI digests. All MRSA isolates, with one exception, belonged to a single clonal type II::NH::D. This clone, which was previously described among MRSA isolates recovered in the early 1990s in European and New York and South American hospitals, showed resistance to beta-lactam antibiotics only and appeared to be associated almost exclusively with pediatric infections ("Pediatric clone" of MRSA). While sharing identical molecular typing properties with the Pediatric clone, the Colombian isolates differed by extensive multidrug resistance and were recovered from patients of all ages. It is also noteworthy that the Brazilian clone of MRSA (XI::B::B), another multidrug-resistant international clone currently widely spread in Brazil, Argentina, Uruguay, Chile, and also in several European countries, was completely absent from this set of isolates from Colombia.

  17. Molecular epidemiology of methicillin-resistant Staphylococcus aureus in a university hospital in northwestern Spain.

    PubMed

    Ariza-Miguel, Jaime; Hernández, Marta; Fernández-Natal, Isabel; Rodríguez-Lázaro, David

    2014-09-01

    Continuous monitoring of methicillin-resistant Staphylococcus aureus (MRSA) is necessary to understand the clonal evolution of successful lineages. In this study, we identified the MRSA clones circulating in a Spanish hospital during a 2-year period, assessed their relationship with antimicrobial resistance profiles, and investigated the presence of the emerging community-associated and livestock-associated MRSA lineages (CA-MRSA, LA-MRSA). CC5-MRSA-IV isolates were the most frequently recovered, which supports the previously reported prevalence of this clone in Spanish hospitals. We observed ST125 isolates that harbored specific cassette chromosome recombinase (ccr) gene elements of the staphylococcal cassette chromosome mec (SCCmec) types IV and VI. That clone, which was first detected only recently, has increased resistance to erythromycin. Furthermore, 94% of the infections were caused by non-multiresistant isolates. Neither CA-MRSA nor LA-MRSA isolates were observed. These findings, along with related events over the last decade, suggest the establishment of a clonal endemic population in the Spanish clinical environment. PMID:26419454

  18. Development of novel antibacterial agents against methicillin-resistant Staphylococcus aureus

    PubMed Central

    Chiu, Hao-Chieh; Lee, Su-Lin; Kapuriya, Naval; Wang, Dasheng; Chen, Yi-Ru; Yu, Sung-Liang; Kulp, Samuel K.; Teng, Lee-Jeng; Chen, Ching-Shih

    2012-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious threat to public health because of its resistance to multiple antibiotics most commonly used to treat infection. In this study, we report the unique ability of the cyclooxygenase-2 (COX-2) inhibitor celecoxib to kill Staphylococcus aureus and MRSA with modest potency. We hypothesize that the anti-Staphylococcus activity of celecoxib could be pharmacologically exploited to develop novel anti-MRSA agents with a distinct mechanism. Examination of an in-house, celecoxib-based focused compound library in conjunction with structural modifications led to the identification of compound 46 as the lead agent with high antibacterial potency against a panel of Staphylococcus pathogens and different strains of MRSA. Moreover, this killing effect is bacteria-specific, as human cancer cells are resistant to 46. In addition, a single intraperitoneal administration of compound 46 at 30 mg/kg improved the survival of MRSA-infected C57BL/6 mice. In light of its high potency in eradicating MRSA in vitro and its in vivo activity, compound 46 and its analogues warrant continued preclinical development as a potential therapeutic intervention against MRSA. PMID:22750009

  19. Methicillin resistant Staphylococcus aureus (MRSA) carriage in different free-living wild animal species in Spain.

    PubMed

    Porrero, M Concepción; Mentaberre, Gregorio; Sánchez, Sergio; Fernández-Llario, Pedro; Gómez-Barrero, Susana; Navarro-Gonzalez, Nora; Serrano, Emmanuel; Casas-Díaz, Encarna; Marco, Ignasi; Fernández-Garayzabal, José-Francisco; Mateos, Ana; Vidal, Dolors; Lavín, Santiago; Domínguez, Lucas

    2013-10-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a life-threatening pathogen in humans and its presence in animals is a public health concern. The aim of this study was to measure the prevalence of MRSA in free-living wild animals. Samples from red deer (n=273), Iberian ibex (n=212), Eurasian Griffon vulture (n=40) and wild boar (n=817) taken from different areas in Spain between June 2008 and November 2011 were analyzed. Characterization of the isolates was performed by spa typing, multi-locus sequence typing (MLST) and antimicrobial susceptibility testing. A low prevalence of MRSA was found with 13 isolates obtained from 12 animals (0.89%; 95% CI: 0.46-1.56). All MRSA sequence types belonged to ST398 (t011 and t1451) and ST1 (t127). Genotypes and antimicrobial susceptibility patterns (tetracycline resistance in ST398 and clindamycin-erythromycin-tetracycline resistance in ST1) suggest that the MRSA found probably originated in livestock (ST398) or humans (ST1). This is the first report of MRSA carriers in free-living wild animals in Europe. Although our data showed that MRSA prevalence is currently low, free-living wild animals might act as reservoir and represent a potential risk for human health.

  20. PHACOS, a functionalized bacterial polyester with bactericidal activity against methicillin-resistant Staphylococcus aureus

    PubMed Central

    Dinjaski, Nina; Fernández-Gutiérrez, Mar; Selvam, Shivaram; Parra-Ruiz, Francisco J.; Lehman, Susan M.; Román, Julio San; García, Ernesto; García, José L.; García, Andrés J.; Prieto, María Auxiliadora

    2013-01-01

    Biomaterial-associated infections represent a significant clinical problem, and treatment of these microbial infections is becoming troublesome due to the increasing number of antibiotic-resistant strains. Here, we report a naturally functionalized bacterial polyhydroxyalkanoate (PHACOS) with antibacterial properties. We demonstrate that PHACOS selectively and efficiently inhibits the growth of methicillin-resistant Staphylococcus aureus (MRSA) both in vitro and in vivo. This ability has been ascribed to the functionalized side chains containing thioester groups. Significantly less (3.2-fold) biofilm formation of S. aureus was detected on PHACOS compared to biofilms formed on control poly(3-hydroxyoctanoate-co-hydroxyhexanoate) and poly(ethylene terephthalate), but no differences were observed in bacterial adhesion among these polymers. PHACOS elicited minimal cytotoxic and inflammatory effects on murine macrophages and supported normal fibroblast adhesion. In vivo fluorescence imaging demonstrated minimal inflammation and excellent antibacterial activity for PHACOS compared to controls in an in vivo model of implant-associated infection. Additionally, reductions in neutrophils and macrophages in the vicinity of sterile PHACOS compared to sterile PHO implant were observed by immunohistochemistry. Moreover, a similar percentage of inflammatory cells was found in the tissue surrounding sterile PHACOS and S. aureus pre-colonized PHACOS implants, and these levels were significantly lower than S. aureus pre-colonized control polymers. These findings support a contact active surface mode of antibacterial action for PHACOS and establish this functionalized polyhydroxyalkanoate as an infection-resistant biomaterial. PMID:24094939

  1. Tolerability of a probiotic in subjects with a history of methicillin-resistant Staphylococcus aureus colonisation.

    PubMed

    Warrack, S; Panjikar, P; Duster, M; Safdar, N

    2014-12-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen of major public health importance. Colonisation precedes infection; thus reducing MRSA carriage may be of benefit for reducing infection. Probiotics represent a novel approach to reducing MRSA carriage. We undertook a pilot feasibility randomised controlled trial of the tolerability and acceptability of probiotics for reducing nasal and intestinal carriage of MRSA. In addition, subjects were screened for vancomycin-resistant enterocococci (VRE). Subjects with a history of MRSA were recruited from a large, academic medical center and randomised to take either a placebo or probiotic (Lactobacillus rhamnosus HN001). Subjects returned to the clinic after four weeks for further testing to determine adherence to the probiotic regimen and colonisation of MRSA. 48 subjects were enrolled and randomised. Nearly 25% were transplant recipients and 30% had diabetes. The probiotic was well tolerated in the study population though minor side effects, such as nausea and bloating, were observed. A majority of the subjects randomised to HN001 had good adherence to the regimen. At the four week time point among subjects randomised to the probiotic, MRSA was detected in 67 and 50% of subjects colonised in the nares and the gastrointestinal tract, respectively. Three subjects who initially tested positive for VRE were negative after four weeks of probiotic exposure. Probiotics were well tolerated in our study population of largely immunocompromised subjects with multiple comorbidities. Adherence to the intervention was good. Probiotics should be studied further for their potential to reduce colonisation by multidrug resistant bacteria. PMID:25213147

  2. Vancomycin for the treatment of methicillin-resistant staphylococcal and enterococcal infections in 15 horses.

    PubMed

    Orsini, James A; Snooks-Parsons, Corinna; Stine, Lynne; Haddock, Marie; Ramberg, Charles F; Benson, Charles E; Nunamaker, David M

    2005-10-01

    We retrospectively reviewed the cases of 15 foals and adult horses in which vancomycin was used, alone or in combination with an aminoglycoside, to treat methicillin-resistant staphylococcal and enterococcal infections. Signalment, presenting complaint, history (including history of treatment for the current complaint), results of bacterial culture and antimicrobial susceptibility testing, treatment, and outcome were reviewed. The average vancomycin dosage was 7.5 mg/kg q8h, administered by intravenous infusion over 30 min. The infection resolved in all 7 horses with soft tissue infections and in 6 of the 8 horses with infections involving a bone or a joint, or both. No adverse effects of vancomycin therapy were noted. Although the number of cases is small, our findings suggest that vancomycin, alone or in combination with an aminoglycoside, is safe and effective for the treatment of resistant staphylococcal and enterococcal infections in horses and foals. However, owing to the importance of staphylococci and enterococci in human medicine and the problems with emerging resistance, we recommend that the use of vancomycin in horses be limited to cases in which culture and susceptibility results clearly indicate that this agent is likely to be effective and in which there is no reasonable alternative. PMID:16479726

  3. Survival of methicillin-resistant Staphylococcus aureus during thermal processing of frankfurters, summer sausage, and ham.

    PubMed

    Campbell, Jonathan A; Dickson, James S; Cordray, Joseph C; Olson, Dennis G; Mendonca, Aubrey F; Prusa, Kenneth J

    2014-01-01

    Infections from antibiotic-resistant bacteria are a major concern for human health professionals around the world. Methicillin-resistant Staphylococcus aureus (MRSA) is just one of the resistant organisms of concern. MRSA prevalence has also been recently reported in retail meat products at rates higher than originally thought. Although the risk of contracting an infection from handling contaminated meat products is thought to be low, very little is known about this organism from a food safety perspective. The objective of this study was to determine the survival of MRSA during thermal processing of frankfurters, summer sausage, and boneless ham. Frankfurters, summer sausage, and boneless ham were manufactured using formulations and processing procedures developed at the Iowa State University meat laboratory. Thermal processing resulted in a significant log reduction (p<0.05) for boneless ham, summer sausage, and frankfurters when compared to uncooked, positive controls for each of the three processed meat products. All products were thermally processed to an internal temperature of 70°C and promptly cooled to 7.2°C. Boneless ham showed the highest log reduction (7.28 logs) from cooking, followed by summer sausage (6.75 logs) and frankfurters (5.53 logs). The results of this study indicate that thermal processing of ham, summer sausage, and frankfurters to 70°C is sufficient to reduce the risk of MRSA as a potential food safety hazard.

  4. PCR-based Approaches for the Detection of Clinical Methicillin-resistant Staphylococcus aureus

    PubMed Central

    Liu, Ying; Zhang, Jiang; Ji, Yinduo

    2016-01-01

    Staphylococcus aureus is an important pathogen that can cause a variety of infections, including superficial and systematic infections, in humans and animals. The persistent emergence of multidrug resistant S. aureus, particularly methicillin-resistant S. aureus, has caused dramatically economic burden and concerns in the public health due to limited options of treatment of MRSA infections. In order to make a correct choice of treatment for physicians and understand the prevalence of MRSA, it is extremely critical to precisely and timely diagnose the pathogen that induces a specific infection of patients and to reveal the antibiotic resistant profile of the pathogen. In this review, we outlined different PCR-based approaches that have been successfully utilized for the rapid detection of S. aureus, including MRSA and MSSA, directly from various clinical specimens. The sensitivity and specificity of detections were pointed out. Both advantages and disadvantages of listed approaches were discussed. Importantly, an alternative approach is necessary to further confirm the detection results from the molecular diagnostic assays. PMID:27335617

  5. Methicillin-resistant Staphylococcus aureus in commercial swine herds is associated with disinfectant and zinc usage.

    PubMed

    Slifierz, Mackenzie Jonathan; Friendship, Robert M; Weese, J Scott

    2015-04-01

    Methicillin-resistant Staphylococcus aureus (MRSA) originating from swine is concerning for public health, but an understanding of the emergence and persistence of MRSA in nursery herds is lacking. The aim of this study was to determine whether MRSA in nursery pigs is associated with particular herd-level parameters, including the use of antimicrobials, disinfectants, and heavy metals, which may be driving the selection and persistence of antimicrobial resistance. Nasal cultures for MRSA were completed for 390 pigs from 26 farms at the end of the suckling phase and again at 3 weeks postweaning. Herd-level information was collected, and a random subset of MRSA isolates was screened for resistance to zinc and quaternary ammonium compounds (QACs). Multivariate analysis revealed that in-feed concentrations of zinc (P < 0.001) and frequent disinfection of nursery pens (P < 0.001) are associated with MRSA shedding in nursery pigs. Furthermore, 62.5% (25/40) of MRSA isolates carried the zinc resistance gene czrC and demonstrated decreased susceptibility to zinc. All MRSA isolates carried at least 1 QAC resistance gene. The most common genotype was qacG qacH smr, which occurred in 32.5% (13/40) of isolates. Seven isolates (17.5%) demonstrated a significant tolerance to benzalkonium chloride, indicating a potential to survive commercial QAC exposure in the presence of organic matter. Overall, these findings indicate that high levels of in-feed zinc and QAC-based disinfectants are important drivers in the selection and persistence of MRSA in commercial swine herds, and these agents may be coselecting for other antimicrobial resistance genes.

  6. A Case of a Methicillin-Resistant Staphylococcus Aureus Retropharyngeal Abscess With Mediastinal Extension in an 11-Month-Old Girl.

    PubMed

    Shanti, Rabie M; Hastings, Mary L; Patel, Stavan; Yeoh, Melvyn S

    2016-04-01

    We present the case of an 11-month-old girl with Mycoplasma pneumoniae-associated pneumonia who was subsequently diagnosed with a methicillin-resistant Staphylococcus aureus retropharyngeal abscess with mediastinal extension. PMID:26541226

  7. Daptomycin efficacy in the central nervous system of a patient with disseminated methicillin-resistant Staphylococcus aureus infection: a case report

    PubMed Central

    2012-01-01

    Introduction Staphylococcus aureus has emerged as a major nosocomial pathogen in the last decades and also represents the second most common pathogen isolated from patients in outpatient settings. Although methicillin-resistant S.aureus infections were traditionally limited to hospitals, community-associated cases of methicillin-resistant S.aureus infections have been reported. In our case, we observed an unexpected event during treatment. Case presentation A 60-year-old Caucasian man developed fever and multiple muscle and brain abscesses caused by Panton-Valentine leukocidin-negative community-associated methicillin-resistant S. aureus. Conclusion Although our patient was given antimicrobials active against the isolated methicillin-resistant S. aureus strain, it was only after the introduction of daptomycin that his skin, soft tissue and muscle lesions and also brain manifestations improved. PMID:22938025

  8. Combinations of β-lactam or aminoglycoside antibiotics with plectasin are synergistic against methicillin-sensitive and methicillin-resistant Staphylococcus aureus.

    PubMed

    Hu, Yanmin; Liu, Alexander; Vaudrey, James; Vaiciunaite, Brigita; Moigboi, Christiana; McTavish, Sharla M; Kearns, Angela; Coates, Anthony

    2015-01-01

    Bacterial infections remain the leading killer worldwide which is worsened by the continuous emergence of antibiotic resistance. In particular, methicillin-sensitive (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) are prevalent and the latter can be difficult to treat. The traditional strategy of novel therapeutic drug development inevitably leads to emergence of resistant strains, rendering the new drugs ineffective. Therefore, rejuvenating the therapeutic potentials of existing antibiotics offers an attractive novel strategy. Plectasin, a defensin antimicrobial peptide, potentiates the activities of other antibiotics such as β-lactams, aminoglycosides and glycopeptides against MSSA and MRSA. We performed in vitro and in vivo investigations to test against genetically diverse clinical isolates of MSSA (n = 101) and MRSA (n = 115). Minimum inhibitory concentrations (MIC) were determined by the broth microdilution method. The effects of combining plectasin with β-lactams, aminoglycosides and glycopeptides were examined using the chequerboard method and time kill curves. A murine neutropenic thigh model and a murine peritoneal infection model were used to test the effect of combination in vivo. Determined by factional inhibitory concentration index (FICI), plectasin in combination with aminoglycosides (gentamicin, neomycin or amikacin) displayed synergistic effects in 76-78% of MSSA and MRSA. A similar synergistic response was observed when plectasin was combined with β-lactams (penicillin, amoxicillin or flucloxacillin) in 87-89% of MSSA and MRSA. Interestingly, no such interaction was observed when plectasin was paired with vancomycin. Time kill analysis also demonstrated significant synergistic activities when plectasin was combined with amoxicillin, gentamicin or neomycin. In the murine models, plectasin at doses as low as 8 mg/kg augmented the activities of amoxicillin and gentamicin in successful treatment of MSSA and MRSA infections. We

  9. Combinations of β-Lactam or Aminoglycoside Antibiotics with Plectasin Are Synergistic against Methicillin-Sensitive and Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Hu, Yanmin; Liu, Alexander; Vaudrey, James; Vaiciunaite, Brigita; Moigboi, Christiana; McTavish, Sharla M.; Kearns, Angela; Coates, Anthony

    2015-01-01

    Bacterial infections remain the leading killer worldwide which is worsened by the continuous emergence of antibiotic resistance. In particular, methicillin-sensitive (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) are prevalent and the latter can be difficult to treat. The traditional strategy of novel therapeutic drug development inevitably leads to emergence of resistant strains, rendering the new drugs ineffective. Therefore, rejuvenating the therapeutic potentials of existing antibiotics offers an attractive novel strategy. Plectasin, a defensin antimicrobial peptide, potentiates the activities of other antibiotics such as β-lactams, aminoglycosides and glycopeptides against MSSA and MRSA. We performed in vitro and in vivo investigations to test against genetically diverse clinical isolates of MSSA (n = 101) and MRSA (n = 115). Minimum inhibitory concentrations (MIC) were determined by the broth microdilution method. The effects of combining plectasin with β-lactams, aminoglycosides and glycopeptides were examined using the chequerboard method and time kill curves. A murine neutropenic thigh model and a murine peritoneal infection model were used to test the effect of combination in vivo. Determined by factional inhibitory concentration index (FICI), plectasin in combination with aminoglycosides (gentamicin, neomycin or amikacin) displayed synergistic effects in 76-78% of MSSA and MRSA. A similar synergistic response was observed when plectasin was combined with β-lactams (penicillin, amoxicillin or flucloxacillin) in 87–89% of MSSA and MRSA. Interestingly, no such interaction was observed when plectasin was paired with vancomycin. Time kill analysis also demonstrated significant synergistic activities when plectasin was combined with amoxicillin, gentamicin or neomycin. In the murine models, plectasin at doses as low as 8 mg/kg augmented the activities of amoxicillin and gentamicin in successful treatment of MSSA and MRSA infections. We

  10. Co-infection of methicillin-resistant Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus and extended spectrum β-lactamase producing Escherichia coli in bovine mastitis--three cases reported from India.

    PubMed

    Bandyopadhyay, Samiran; Samanta, Indranil; Bhattacharyya, Debaraj; Nanda, Pramod Kumar; Kar, Debasish; Chowdhury, Jayanta; Dandapat, Premanshu; Das, Arun Kumar; Batul, Nayan; Mondal, Bimalendu; Dutta, Tapan Kumar; Das, Gunjan; Das, Bikash Chandra; Naskar, Syamal; Bandyopadhyay, Uttam Kumar; Das, Suresh Chandra; Bandyopadhyay, Subhasish

    2015-03-01

    Emergence of antimicrobial resistance among bovine mastitis pathogens is the major cause of frequent therapeutic failure and a cause of concern for veterinary practitioners. This study describes intra-mammary infection of methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum β-lactamase (ESBL) producing Escherichia coli in two Holstein Friesian crossbred cows with subclinical mastitis and one non-descript cow with clinical mastitis in two different districts of West Bengal, India. In total, three MRSE, one MRSA and three ESBL producing E. coli were isolated from these cases. Both the crossbreds were detected with MRSE (HFSE1 and HFSE2) and ESBL producing E. coli (HFEC1 and HFEC2), whereas, simultaneous infection of three pathogens viz. MRSA (NDSA1), MRSE (NDSE1) and ESBL producing E. coli (NDEC1) was found in the non-descript cow. The methicillin-resistant isolates possessed mecA gene and exhibited resistance to various antibiotics such as amikacin, tetracycline and glycopeptides. The ESBL producers were positive for blaCTX-M and blaTEM genes; in addition, HFEC1 and HFEC2 were positive for blaSHV and possessed the genes for class I integron (int1), sulphonamide resistance (sul1), quinolone resistance (qnrS) and other virulence factors (papC, iucD and ESTA1). All the ESBL producers exhibited resistance to a variety of antibiotics tested including third- and fourth-generation cephalosporins and were also intermediately resistant to carbapenems. This is the first ever report on simultaneous occurrence of MRSE, MRSA and ESBL producing E. coli in bovine mastitis indicating a major concern for dairy industry and public health as well.

  11. Antibiotic reduction campaigns do not necessarily decrease bacterial resistance: the example of methicillin-resistant Staphylococcus aureus.

    PubMed

    Kardas-Sloma, Lidia; Boëlle, Pierre-Yves; Opatowski, Lulla; Guillemot, Didier; Temime, Laura

    2013-09-01

    Interventions designed to reduce antibiotic consumption are under way worldwide. While overall reductions are often achieved, their impact on the selection of antibiotic-resistant selection cannot be assessed accurately from currently available data. We developed a mathematical model of methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) transmission inside and outside the hospital. A systematic simulation study was then conducted with two objectives: to assess the impact of antibiotic class-specific changes during an antibiotic reduction period and to investigate the interactions between antibiotic prescription changes in the hospital and the community. The model reproduced the overall reduction in MRSA frequency in French intensive-care units (ICUs) with antibiotic consumption in France from 2002 to 2003 as an input. However, the change in MRSA frequency depended on which antibiotic classes changed the most, with the same overall 10% reduction in antibiotic use over 1 year leading to anywhere between a 69% decrease and a 52% increase in MRSA frequency in ICUs and anywhere between a 37% decrease and a 46% increase in the community. Furthermore, some combinations of antibiotic prescription changes in the hospital and the community could act in a synergistic or antagonistic way with regard to overall MRSA selection. This study shows that class-specific changes in antibiotic use, rather than overall reductions, need to be considered in order to properly anticipate the impact of an antibiotic reduction campaign. It also highlights the fact that optimal gains will be obtained by coordinating interventions in hospitals and in the community, since the effect of an intervention in a given setting may be strongly affected by exogenous factors.

  12. Phenotypic and genotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA) from different sources in China.

    PubMed

    Chao, Guoxiang; Zhang, Xiaoping; Zhang, Xiaorong; Huang, Yao; Xu, Lan; Zhou, Liping; Yang, Weixia; Jiang, Yuan; Xue, Feng; Wu, Yantao

    2013-03-01

    A diverse collection of 261 Staphylococcus aureus strains from human, animal, food, and environmental sources were tested for the presence and type of SCCmec elements, antibiotic susceptibility to various antibiotics, and non-ß-lactam antibiotic resistance genes. About 18.39% (48/261) of strains were methicillin-resistant S. aureus (MRSA) including 29.75% (36/121) human strains of which 29 strains were hospital-acquired MRSA (HA-MRSA) and 7 strains were community-associated MRSA (CA-MRSA) and 19.67% (12/61) animal strains that all were CA-MRSA strains. The percentage of CA-MRSA strains from animals was significantly higher than that from human (p<0.01). Most of MRSA strains and a part of methicillin-susceptible S. aureus (MSSA) strains harbored unique combinations of non-ß-lactamase genes aac(6')/aph(2″), aph(3')-III, ant (4',4″), ermA, ermC, mrsA, tetM, and tetK. Antibiotic resistance genes were detected more frequently in HA-MRSA strains than in CA-MRSA strains (p<0.01). MRSA strains and MSSA strains had 22 and 39 antibiotic profiles to 15 tested antibiotics, respectively. The resistant proportion was higher in HA-MRSA strains than in CA-MSSA strains for various antibiotics, as well as higher in MRSA strains than in MSSA strains. Animal MRSA reservoirs (particularly pigs and cows) might represent an important source of human CA-MRSA. CA-MRSA strains might acquire more different resistance genes gradually, depending on the selective pressure of antibiotics in different regions or environments. CA-MRSA is not yet endemic in China, but could be prevalent in future, contributing to its acquiring more resistance genes and huge animal sources. Infection with multidrug-resistant MSSA strains acquired from food, animal, and human sources might also become a significant problem for human medicine, which warrants further study.

  13. Characterization of methicillin-resistant Staphylococcus aureus associated with nosocomial infections in the University Hospital, Kuala Lumpur.

    PubMed

    Hanifah, Y A; Hiramatsu, K; Yokota, T

    1992-05-01

    Methicillin-resistant Staphylococcus aureus (MRSA) as a hospital pathogen has presented many clinical problems in the University Hospital, Kuala Lumpur, Malaysia since 1978. The need for control of spread of these organisms became evident by 1985 when it was noted that the incidence of MRSA among S. aureus isolated from hospital inpatients had increased from 11.5% in 1979 to 18.8% in 1985. The characteristics of 50 MRSA isolates associated with nosocomial infections in the hospital are described here. The predominant strains produced Type IV coagulase and 84% of isolates studied showed moderate to high resistance to methicillin with MIC values of 25 mg l-1 or higher. All the MRSA isolates that could be phagetyped were susceptible to Group III phages, with 76.6% of the isolates being susceptible to phage 85. At least 10 different patterns were distinguishable by plasmid typing, the majority of isolates harbouring up to four small plasmids.

  14. Sternoclavicular septic arthritis due to methicillin-resistant Staphylococcus aureus in a patient with a suprapubic catheter.

    PubMed

    Monteiro, Nadine; Moleiro, Filipa; Lérias, Graça; Silva, Alberto Mello

    2015-01-01

    We report a case of a 74-year-old man who presented to the emergency department with a 1-week history of fever. He had a meatal stenosis and had a suprapubic catheter for 10 months, and had a recent hospitalisation for urosepsis with bacteraemia due to methicillin-resistant Staphylococcus aureus after manipulation of the catheter. Clinical examinations were performed in the emergency department and the patient was hospitalised with the diagnosis of recurrent urinary tract infection. The following day, we noticed the development of a mass in the left sternoclavicular joint with inflammatory signs and excruciating pain. Ultrasonographic findings led to the diagnosis of left sternoclavicular synovitis, and methicillin-resistant S. aureus grew in blood cultures leading to the diagnosis of sternoclavicular septic arthritis. Treatment with vancomycin and gentamicin was started and maintained for 4 weeks with complete resolution of symptoms and no complications or sequelae.

  15. Ductus arteriosus aneurysm with community-acquired methicillin-resistant Staphylococcus aureus infection and spontaneous rupture: a potentially fatal quandary.

    PubMed

    Stewart, Audra; Dyamenahalli, Umesh; Greenberg, S Bruce; Drummond-Webb, Jonathan

    2006-06-01

    We present the case of a 6-month-old previously healthy girl who presented with high fever, labored breathing, and an enlarged cardiac silhouette on her chest radiograph. Comprehensive evaluation discovered a ductus arteriosus aneurysm and pericardial effusion with methicillin-resistant Staphylococcus aureus bacteremia. Despite pericardiocentesis and appropriate intravenous antibiotics, there was rapid enlargement of the aneurysm and accumulation of echogenic material within the ductus arteriosus aneurysm. Infected aneurysm rupture was identified during emergency surgery. This infant also had vocal cord paresis, a likely complication of the surgery. The clinical course, diagnosis, and treatment of this patient are discussed. Infection of a ductus arteriosus or an infected ductal arteriosus aneurysm is a rare and potentially fatal clinical entity. In the era of increasing community-acquired methicillin-resistant S aureus infections, this is a diagnosis that requires a high index of suspicion.

  16. Sternoclavicular septic arthritis due to methicillin-resistant Staphylococcus aureus in a patient with a suprapubic catheter.

    PubMed

    Monteiro, Nadine; Moleiro, Filipa; Lérias, Graça; Silva, Alberto Mello

    2015-01-01

    We report a case of a 74-year-old man who presented to the emergency department with a 1-week history of fever. He had a meatal stenosis and had a suprapubic catheter for 10 months, and had a recent hospitalisation for urosepsis with bacteraemia due to methicillin-resistant Staphylococcus aureus after manipulation of the catheter. Clinical examinations were performed in the emergency department and the patient was hospitalised with the diagnosis of recurrent urinary tract infection. The following day, we noticed the development of a mass in the left sternoclavicular joint with inflammatory signs and excruciating pain. Ultrasonographic findings led to the diagnosis of left sternoclavicular synovitis, and methicillin-resistant S. aureus grew in blood cultures leading to the diagnosis of sternoclavicular septic arthritis. Treatment with vancomycin and gentamicin was started and maintained for 4 weeks with complete resolution of symptoms and no complications or sequelae. PMID:25694643

  17. Evolution of community- and healthcare-associated methicillin-resistant Staphylococcus aureus☆

    PubMed Central

    Uhlemann, Anne-Catrin; Otto, Michael; Lowy, Franklin D.; DeLeo, Frank R.

    2013-01-01

    Staphylococcus aureus is a prominent cause of human infections globally. The high prevalence of infections is compounded by antibiotic resistance—a significant problem for treatment. Methicillin-resistant S. aureus (MRSA) is endemic in hospitals and healthcare facilities worldwide, and is an increasingly common cause of community-associated bacterial infections in industrialized countries. Although much focus is placed on the role of S. aureus as a human pathogen, it is in fact a human commensal organism that has had a relatively long coexistence with the human host. Many S. aureus infections can be explained by host susceptibility or other predisposing risk factors. On the other hand, the emergence/re-emergence of successful S. aureus clones (referred to as epidemic waves) suggests a rapid bacterial adaption and evolution, which includes the emergence of antibiotic resistance and increased virulence and/or transmissibility. It is within this context that we review our understanding of selected S. aureus epidemic waves, and highlight the use of genome sequencing as a means to better understand the evolution of each lineage. PMID:23648426

  18. Antibacterial activity of oxyresveratrol against methicillin-resistant Staphylococcus aureus and its mechanism

    PubMed Central

    Joung, Dae-Ki; Mun, Su-Hyun; Choi, Sung-Hoon; Kang, Ok-Hwa; Kim, Sung-Bae; Lee, Young-Seob; Zhou, Tian; Kong, Ryong; Choi, Jang-Gi; Shin, Dong-Won; Kim, Youn-Chul; Lee, Dong-Sung; Kwon, Dong-Yeul

    2016-01-01

    Oxyresveratrol (ORV) is a naturally occurring compound found in mulberries that exhibits a wide spectrum of biological activities. However, the underlying mechanism of the action of ORV against the methicillin-resistant S. aureus (MRSA) pathogen has not yet been reported. MRSA is multidrug-resistant, causing skin and other types of infections. The aim of the present study was to examine the antimicrobial activity of ORV and the underlying mechanism of its action on MRSA. The antibacterial activity of ORV was evaluated using a minimum inhibitory concentration (MIC) assay, and the mechanism of its antibacterial action on S. aureus was investigated using a combination of ORV with detergent, ATPase inhibitors and peptidoglycan (PGN). In addition, the survival characteristics and changes in MRSA morphology were monitored using transmission electron microscopy (TEM). The MIC value of ORV against all S. aureus strains was found to be 125 µg/ml. The optical density at 600 nm of each suspension treated using a combination of ORV with Triton X-100, N,N'-dicyclohexylcarbodiimide or sodium azide was reduced by 68.9–89.8% compared with the value upon treatment with ORV alone. In the ORV and PGN combination assay, direct binding of ORV with PGN from S. aureus was evident. Furthermore, TEM examination of MRSA treated with ORV showed alterations in septa formation. In conclusion, these results showed that ORV has a strong antibacterial effect against S. aureus, mainly by increasing membrane permeability and inhibiting ATPase when combined with other drugs. PMID:27588079

  19. Methicillin-resistant Staphylococcus aureus mandibular osteomyelitis in an extremely low birth weight preterm infant.

    PubMed

    Martini, Silvia; Tumietto, Fabio; Sciutti, Rita; Greco, Laura; Faldella, Giacomo; Corvaglia, Luigi

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an established nosocomial pathogen with frequent multidrug resistance. The immaturity of the immune system along with intravascular lines and empirical antibiotic treatments place hospitalized preterm infants at major risk of MRSA infection.We report a case of MRSA mandibular osteomyelitis complicating a persistent S. aureus bacteremia in a 23-week preterm infant. From the first weeks of life, the infant showed recurrent C-reactive protein (CRP) elevation, associated with S. aureus bacteremia. Antibiotic courses, including vancomycin and linezolid, were performed with transitory normalization of blood parameters. On day 74, the infant suddenly deteriorated and showed a significant increase of both CRP and procalcitonin. Empiric vancomycin and piperacillin-tazobactam treatment was started; nevertheless, she developed a progressive hard swelling of neck and mandible. Radiological evaluation revealed a mandibular osteomyelitis complicated by an abscess, whose culture grew MRSA. Vancomycin was thus changed to teicoplanin and complete clinical and radiological healing was gradually achieved.In the presence of major risk factors, persistent bacteremia and nonspecific symptoms, a localized focus of infection should be suspected. Microbiological diagnosis should always be attempted and antibiotic treatment should be guided by both susceptibility results and clinical response. PMID:26239708

  20. A Field Guide to Pandemic, Epidemic and Sporadic Clones of Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Monecke, Stefan; Coombs, Geoffrey; Shore, Anna C.; Coleman, David C.; Akpaka, Patrick; Borg, Michael; Chow, Henry; Ip, Margaret; Jatzwauk, Lutz; Jonas, Daniel; Kadlec, Kristina; Kearns, Angela; Laurent, Frederic; O'Brien, Frances G.; Pearson, Julie; Ruppelt, Antje; Schwarz, Stefan; Scicluna, Elizabeth; Slickers, Peter; Tan, Hui-Leen; Weber, Stefan; Ehricht, Ralf

    2011-01-01

    In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements. PMID:21494333

  1. Role of Berberine in the Treatment of Methicillin-Resistant Staphylococcus aureus Infections

    NASA Astrophysics Data System (ADS)

    Chu, Ming; Zhang, Ming-Bo; Liu, Yan-Chen; Kang, Jia-Rui; Chu, Zheng-Yun; Yin, Kai-Lin; Ding, Ling-Yu; Ding, Ran; Xiao, Rong-Xin; Yin, Yi-Nan; Liu, Xiao-Yan; Wang, Yue-Dan

    2016-04-01

    Berberine is an isoquinoline alkaloid widely used in the treatment of microbial infections. Recent studies have shown that berberine can enhance the inhibitory efficacy of antibiotics against clinical multi-drug resistant isolates of methicillin-resistant Staphylococcus aureus (MRSA). However, the underlying mechanisms are poorly understood. Here, we demonstrated that sub-minimum inhibitory concentrations (MICs) of berberine exhibited no bactericidal activity against MRSA, but affected MRSA biofilm development in a dose dependent manner within the concentration ranging from 1 to 64 μg/mL. Further study indicated that berberine inhibited MRSA amyloid fibrils formation, which consist of phenol-soluble modulins (PSMs). Molecular dynamics simulation revealed that berberine could bind with the phenyl ring of Phe19 in PSMα2 through hydrophobic interaction. Collectively, berberine can inhibit MRSA biofilm formation via affecting PSMs’ aggregation into amyloid fibrils, and thereby enhance bactericidal activity of antibiotics. These findings will provide new insights into the multiple pharmacological properties of berberine in the treatment of microbial-generated amyloid involved diseases.

  2. Nano-thick calcium oxide armed titanium: boosts bone cells against methicillin-resistant Staphylococcus aureus

    NASA Astrophysics Data System (ADS)

    Cao, Huiliang; Qin, Hui; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Meng, Fanhao; Zhang, Xianlong; Liu, Xuanyong

    2016-02-01

    Since the use of systemic antibiotics for preventing acute biomaterial-associated infections (BAIs) may build up bacterial resistance and result in huge medical costs and unpredictable mortality, new precaution strategies are required. Here, it demonstrated that titanium armed with a nano-thick calcium oxide layer was effective on averting methicillin-resistant Staphylococcus aureus (MRSA) infections in rabbits. The calcium oxide layer was constructed by, firstly, injecting of metallic calcium into titanium via a plasma immersion ion implantation process, and then transforming the outer most surface into oxide by exposing to the atmosphere. Although the calcium oxide armed titanium had a relative low reduction rate (~74%) in growth of MRSA in vitro, it could markedly promote the osteogenic differentiation of bone marrow stem cells (BMSCs), restore local bone integration against the challenge of MRSA, and decrease the incidence of MRSA infection with a rate of 100% (compared to the titanium control). This study demonstrated for the first time that calcium, as one of the major elements in a human body, could be engineered to avert MRSA infections, which is promising as a safe precaution of disinfection for implantable biomedical devices.

  3. Structure elucidation of anti-methicillin resistant Staphylococcus aureus (MRSA) flavonoids from balsam poplar buds.

    PubMed

    Simard, François; Gauthier, Charles; Legault, Jean; Lavoie, Serge; Mshvildadze, Vakhtang; Pichette, André

    2016-09-15

    There is nowadays an urgent need for developing novel generations of antibiotic agents due to the increased resistance of pathogenic bacteria. As a rich reservoir of structurally diverse compounds, plant species hold promise in this regard. Within this framework, we isolated a unique series of antibacterial flavonoids, named balsacones N-U, featuring multiple cinnamyl chains on the flavan skeleton. The structures of these compounds, isolated as racemates, were determined using extensive 1D and 2D NMR analysis in tandem with HRMS. Balsacones N-U along with previously isolated balsacones A-M were evaluated for their antibacterial activity against clinical isolates of methicillin resistant Staphylococcus aureus (MRSA). Several of the tested balsacones were potent anti-MRSA agents showing MIC values in the low micromolar range. Structure-activity relationships study highlighted some important parameters involved in the antibacterial activity of balsacones such as the presence of cinnamyl and cinnamoyl chains at the C-3 and C-8 positions of the flavan skeleton, respectively. These results suggest that balsacones could represent a potential novel class of naturally occurring anti-MRSA agents.

  4. SLPW: A Virulent Bacteriophage Targeting Methicillin-Resistant Staphylococcus aureus In vitro and In vivo.

    PubMed

    Wang, Zhaofei; Zheng, Panpan; Ji, Wenhui; Fu, Qiang; Wang, Hengan; Yan, Yaxian; Sun, Jianhe

    2016-01-01

    Staphylococcus aureus (S. aureus) is a Gram-positive pathogen causing a variety of infections in humans and animals. Extensive use of antibiotics has led to the emergence of methicillin-resistant S. aureus (MRSA). As an alternative antibacterial agent against drug-resistant S. aureus, a lytic phage, designated SLPW, was isolated from fecal sewage in a pig farm. The SLPW was morphologically classified under Podoviridae and contains a double-stranded DNA genome. The genome of SLPW was 17,861 bp (29.35% G+C) containing 20 open reading frames and lacked regions encoding lysogeny-related integrase gene and cI repressor gene. Phage SLPW showed a broad host range and high efficiency of plating against various types of S. aureus. One-step growth curve showed a short latency period (10 min) and a long lytic period (120 min). Phage SLPW remained stable under a wide range of temperatures or pH and was almost unaffected in chloroform or ultraviolet light. Further, it efficiently lysed MRSA strains in vitro and in vivo. Intraperitoneal phage administration at 1 h post-infection cured the mice and reduced the bacterial expression of inflammatory cytokines in mice. Specifically, the phage SLPW displayed a wide antibacterial spectrum. It was therapeutically effective against intra-abdominal infection in mice harboring different multilocus sequence typing (MLST) types of S. aureus strains. Therefore, phage SLPW is a potential therapeutic agent against MRSA infections. PMID:27379064

  5. Control of spread of Methicillin Resistant Staphylococcus aureus (MRSA) in Burns Units.

    PubMed

    Muthotho, James N.; Waiyaki, Peter G.; Mbalu, Michael; Wairugu, Anne; Mwanthi, Beth; Odongo, Ben

    1995-02-01

    Results of four years' studies from a number of hospitals in Kenya have shown that nosocomial infections in burns units are due to Methicillin Resistant Staphylococcus aureus (MRSA). Through chromosomal DNA and plasmid DNA, the stain is highly resistant to sulphonamide ointment and other antibiotics. 90% of patients admitted in burns units get colonized or infected with MRSA. The strain prolongs the duration of patients in hospitals. The burns degenerate to second and third degree burns, thereby necessitating skin grafting. The environment has been found to be contaminated with this strain with some staff members having chronic throat infections. Minocycline was found to be effective in treating the infected staff members. Cleaning this environment with Sodium dichloroisocyanurate (precepts)/Sodium hypochlorite (JIK) reduced drastically the mechanical transmission of bacteria in the units. The duration of stay of the patient was reduced. This shows that MRSA which is spread in government and private hospitals can cheaply be controlled by the proper use of disinfectants, antiseptics, and use of effective antibiotics when necessary. PMID:12160450

  6. Structure elucidation of anti-methicillin resistant Staphylococcus aureus (MRSA) flavonoids from balsam poplar buds.

    PubMed

    Simard, François; Gauthier, Charles; Legault, Jean; Lavoie, Serge; Mshvildadze, Vakhtang; Pichette, André

    2016-09-15

    There is nowadays an urgent need for developing novel generations of antibiotic agents due to the increased resistance of pathogenic bacteria. As a rich reservoir of structurally diverse compounds, plant species hold promise in this regard. Within this framework, we isolated a unique series of antibacterial flavonoids, named balsacones N-U, featuring multiple cinnamyl chains on the flavan skeleton. The structures of these compounds, isolated as racemates, were determined using extensive 1D and 2D NMR analysis in tandem with HRMS. Balsacones N-U along with previously isolated balsacones A-M were evaluated for their antibacterial activity against clinical isolates of methicillin resistant Staphylococcus aureus (MRSA). Several of the tested balsacones were potent anti-MRSA agents showing MIC values in the low micromolar range. Structure-activity relationships study highlighted some important parameters involved in the antibacterial activity of balsacones such as the presence of cinnamyl and cinnamoyl chains at the C-3 and C-8 positions of the flavan skeleton, respectively. These results suggest that balsacones could represent a potential novel class of naturally occurring anti-MRSA agents. PMID:27436809

  7. Role of Berberine in the Treatment of Methicillin-Resistant Staphylococcus aureus Infections

    PubMed Central

    Chu, Ming; Zhang, Ming-bo; Liu, Yan-chen; Kang, Jia-rui; Chu, Zheng-yun; Yin, Kai-lin; Ding, Ling-yu; Ding, Ran; Xiao, Rong-xin; Yin, Yi-nan; Liu, Xiao-yan; Wang, Yue-dan

    2016-01-01

    Berberine is an isoquinoline alkaloid widely used in the treatment of microbial infections. Recent studies have shown that berberine can enhance the inhibitory efficacy of antibiotics against clinical multi-drug resistant isolates of methicillin-resistant Staphylococcus aureus (MRSA). However, the underlying mechanisms are poorly understood. Here, we demonstrated that sub-minimum inhibitory concentrations (MICs) of berberine exhibited no bactericidal activity against MRSA, but affected MRSA biofilm development in a dose dependent manner within the concentration ranging from 1 to 64 μg/mL. Further study indicated that berberine inhibited MRSA amyloid fibrils formation, which consist of phenol-soluble modulins (PSMs). Molecular dynamics simulation revealed that berberine could bind with the phenyl ring of Phe19 in PSMα2 through hydrophobic interaction. Collectively, berberine can inhibit MRSA biofilm formation via affecting PSMs’ aggregation into amyloid fibrils, and thereby enhance bactericidal activity of antibiotics. These findings will provide new insights into the multiple pharmacological properties of berberine in the treatment of microbial-generated amyloid involved diseases. PMID:27103062

  8. Nano-thick calcium oxide armed titanium: boosts bone cells against methicillin-resistant Staphylococcus aureus

    PubMed Central

    Cao, Huiliang; Qin, Hui; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Meng, Fanhao; Zhang, Xianlong; Liu, Xuanyong

    2016-01-01

    Since the use of systemic antibiotics for preventing acute biomaterial-associated infections (BAIs) may build up bacterial resistance and result in huge medical costs and unpredictable mortality, new precaution strategies are required. Here, it demonstrated that titanium armed with a nano-thick calcium oxide layer was effective on averting methicillin-resistant Staphylococcus aureus (MRSA) infections in rabbits. The calcium oxide layer was constructed by, firstly, injecting of metallic calcium into titanium via a plasma immersion ion implantation process, and then transforming the outer most surface into oxide by exposing to the atmosphere. Although the calcium oxide armed titanium had a relative low reduction rate (~74%) in growth of MRSA in vitro, it could markedly promote the osteogenic differentiation of bone marrow stem cells (BMSCs), restore local bone integration against the challenge of MRSA, and decrease the incidence of MRSA infection with a rate of 100% (compared to the titanium control). This study demonstrated for the first time that calcium, as one of the major elements in a human body, could be engineered to avert MRSA infections, which is promising as a safe precaution of disinfection for implantable biomedical devices. PMID:26899567

  9. Interactions of methicillin resistant Staphylococcus aureus USA300 and Pseudomonas aeruginosa in polymicrobial wound infection.

    PubMed

    Pastar, Irena; Nusbaum, Aron G; Gil, Joel; Patel, Shailee B; Chen, Juan; Valdes, Jose; Stojadinovic, Olivera; Plano, Lisa R; Tomic-Canic, Marjana; Davis, Stephen C

    2013-01-01

    Understanding the pathology resulting from Staphylococcus aureus and Pseudomonas aeruginosa polymicrobial wound infections is of great importance due to their ubiquitous nature, increasing prevalence, growing resistance to antimicrobial agents, and ability to delay healing. Methicillin-resistant S. aureus USA300 is the leading cause of community-associated bacterial infections resulting in increased morbidity and mortality. We utilized a well-established porcine partial thickness wound healing model to study the synergistic effects of USA300 and P. aeruginosa on wound healing. Wound re-epithelialization was significantly delayed by mixed-species biofilms through suppression of keratinocyte growth factor 1. Pseudomonas showed an inhibitory effect on USA300 growth in vitro while both species co-existed in cutaneous wounds in vivo. Polymicrobial wound infection in the presence of P. aeruginosa resulted in induced expression of USA300 virulence factors Panton-Valentine leukocidin and α-hemolysin. These results provide evidence for the interaction of bacterial species within mixed-species biofilms in vivo and for the first time, the contribution of virulence factors to the severity of polymicrobial wound infections.

  10. Ceftaroline Fosamil Use in 2 Pediatric Patients With Invasive Methicillin-Resistant Staphylococcus aureus Infections.

    PubMed

    Williams, Amanda W; Newman, Patrick M; Ocheltree, Sara; Beaty, Rachel; Hassoun, Ali

    2015-01-01

    Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is one of the most common pathogens causing pediatric infections including skin and soft tissue infections, pyogenic arthritis, osteomyelitis, and septic shock. For decades, patients were treated with antibiotics such as vancomycin and clindamycin, but there is an increasing incidence of resistance to these traditional therapies. We describe 2 cases of patients with CA-MRSA invasive infections with bacteremia who experienced vancomycin therapy failure but who were successfully treated with ceftaroline fosamil. Case 1 involves an 8-year-old Hispanic male who was diagnosed with CA-MRSA bacteremia, thigh abscess, and osteomyelitis. The patient was admitted to the pediatric intensive care unit in septic shock. Case 2 involves an 8-year-old Caucasian male who was diagnosed with CA-MRSA sepsis, right arm abscess, and osteomyelitis. We were able to successfully treat both patients with CA-MRSA sepsis and invasive infection-who failed vancomycin therapy-with ceftaroline fosamil with no adverse efiects. Despite the positive outcome in both pediatric patients, clinical trials with ceftaroline fosamil are needed to further support its use in pediatric patients.

  11. Prevalence of methicillin resistant Staphylococcus aureus in school children of Pokhara.

    PubMed

    Rijal, K R; Pahari, N; Shrestha, B K; Nepal, A K; Paudel, B; Mahato, P; Skalko-Basnet, N

    2008-09-01

    Present study was carried out to find out the prevalence of methicillin resistant Staphylococcus aureus (MRSA) in school children of Pokhara city in western, Nepal. A total of 184 randomly selected children younger than 15 years were included in the study. Nasal swabs collected were subjected to standard bacteriological culture. S. aureus isolates were identified by mannitol fermentation, coagulase positivity and DNase positivity. Antimicrobial susceptibility test was performed on muller-hinton agar (MHA) by modified Kirby-Bauer disc diffusion method. Out of total 184 nasal swabs, S. aureus was isolated in 31.0% (n=57). Among the isolates, 35.1% (n=20) were from male children whereas 64.9% (n=37) were from female. There was no significant sex difference in colonization of S. aureus. Out of 57 isolates, 56.1% (n=32) were MRSA. MRSA isolates indicated relatively high rate of resistance to antibiotic cloxacillin (68.7%) followed by ofloxacin (40.6%), tetracycline (15.6%), erythromycin (9.4%), ciprofloxacin (6.2%) and vancomycin (3.1%).This study showed a high prevalence of MRSA carriage in school children indicating the spread of MRSA in the community.

  12. Community Acquisition of Gentamicin-Sensitive Methicillin-Resistant Staphylococcus aureus in Southeast Queensland, Australia

    PubMed Central

    Nimmo, Graeme R.; Schooneveldt, Jacqueline; O'Kane, Gabrielle; McCall, Brad; Vickery, Alison

    2000-01-01

    Community-acquired methicillin-resistant Staphylococcus aureus (MRSA) susceptible to gentamicin has been reported in a number of countries in the 1990s. To study the acquisition of gentamicin-sensitive MRSA (GS-MRSA) in southeast Queensland and the relatedness of GS-MRSA to other strains of MRSA, 35 cases of infection due to GS-MRSA from October 1997 through September 1998 were examined retrospectively to determine the mode of acquisition and risk factors for MRSA acquisition. Thirty-one isolates from the cases were examined using a variety of methods (antibiotyping, phage typing, pulsed-field gel electrophoresis [PFGE] fingerprinting, and coagulase typing by restriction analysis of PCR products) and were compared with strains of local hospital-acquired gentamicin-resistant MRSA (GR-MRSA) and of Western Australian MRSA (WA-MRSA). Only 6 of 23 cases of community-acquired GS-MRSA had risk factors for MRSA acquisition. Twenty of 21 isolates from cases of community-acquired infection were found to be related by PFGE and coagulase typing and had similar phage typing patterns. Hospital- and nursing home-acquired GS-MRSA strains were genetically and phenotypically diverse. Community-acquired GS-MRSA strains were not related to nosocomial GR-MRSA or WA-MRSA, but phage typing results suggest that they are related to GS-MRSA previously reported in New Zealand. PMID:11060046

  13. SLPW: A Virulent Bacteriophage Targeting Methicillin-Resistant Staphylococcus aureus In vitro and In vivo

    PubMed Central

    Wang, Zhaofei; Zheng, Panpan; Ji, Wenhui; Fu, Qiang; Wang, Hengan; Yan, Yaxian; Sun, Jianhe

    2016-01-01

    Staphylococcus aureus (S. aureus) is a Gram-positive pathogen causing a variety of infections in humans and animals. Extensive use of antibiotics has led to the emergence of methicillin-resistant S. aureus (MRSA). As an alternative antibacterial agent against drug-resistant S. aureus, a lytic phage, designated SLPW, was isolated from fecal sewage in a pig farm. The SLPW was morphologically classified under Podoviridae and contains a double-stranded DNA genome. The genome of SLPW was 17,861 bp (29.35% G+C) containing 20 open reading frames and lacked regions encoding lysogeny-related integrase gene and cI repressor gene. Phage SLPW showed a broad host range and high efficiency of plating against various types of S. aureus. One-step growth curve showed a short latency period (10 min) and a long lytic period (120 min). Phage SLPW remained stable under a wide range of temperatures or pH and was almost unaffected in chloroform or ultraviolet light. Further, it efficiently lysed MRSA strains in vitro and in vivo. Intraperitoneal phage administration at 1 h post-infection cured the mice and reduced the bacterial expression of inflammatory cytokines in mice. Specifically, the phage SLPW displayed a wide antibacterial spectrum. It was therapeutically effective against intra-abdominal infection in mice harboring different multilocus sequence typing (MLST) types of S. aureus strains. Therefore, phage SLPW is a potential therapeutic agent against MRSA infections. PMID:27379064

  14. Pharmacological Properties of the Marine Natural Product Marinopyrrole A against Methicillin-Resistant Staphylococcus aureus ▿

    PubMed Central

    Haste, Nina M.; Hughes, Chambers C.; Tran, Dan N.; Fenical, William; Jensen, Paul R.; Nizet, Victor; Hensler, Mary E.

    2011-01-01

    The ongoing spread of methicillin-resistant Staphylococcus aureus (MRSA) strains in hospital and community settings presents a great challenge to public health and illustrates the urgency of discovering new antibiotics. Marinopyrrole A is a member of a structurally novel class of compounds identified from a species of marine-derived streptomycetes with evidence of antistaphylococcal activity. We show that marinopyrrole A has potent concentration-dependent bactericidal activity against clinically relevant hospital- and community-acquired MRSA strains, a prolonged postantibiotic effect superior to that of the current first-line agents vancomycin and linezolid, and a favorable resistance profile. Marinopyrrole A showed limited toxicity to mammalian cell lines (at >20× MIC). However, its antibiotic activity against MRSA was effectively neutralized by 20% human serum. A variety of marinopyrrole analogs were isolated from culture or synthetically produced to try to overcome the inhibitory effect of serum. While many of these compounds retained potent bactericidal effect against MRSA, their activities were also inhibited by serum. Marinopyrrole A has significant affinity for plastic and may therefore have potential as a potent anti-MRSA agent in cutaneous, intracatheter, or antibiotic-lock applications. PMID:21502631

  15. Activity of the streptogramin antibiotic etamycin against methicillin-resistant Staphylococcus aureus

    PubMed Central

    Haste, Nina M.; Perera, Varahenage; Maloney, Katherine N.; Tran, Dan N.; Jensen, Paul; Fenical, William; Nizet, Victor; Hensler, Mary E.

    2010-01-01

    The alarming rise of hospital- and community-associated methicillin-resistant Staphylococcus aureus (HA- and CA-MRSA) infections has prompted a desperate search for novel antibiotics. We discovered the streptogramin antibiotic, etamycin, for the first time from a newly discovered marine actinomycete and characterized its activity against a panel of HA- and CA-MRSA strains. Etamycin was extracted and purified from a previously uncharacterized marine-derived actinomycete, designated strain CNS-575, as a three-rotamer species as determined by two-dimensional nuclear magnetic resonance (NMR) spectroscopy. Etamycin demonstrated potent activity against hospital- and community-associated strains of MRSA in microbroth dilution assays, with minimum inhibitory concentrations (MIC) as low as 1 – 2 mg/L against HA- and CA-MRSA strains. Furthermore, etamycin was also active against other Gram-positive and several Gram-negative pathogens and was found to be non-cytotoxic at concentrations more than 20-fold above the MIC. Etamycin displayed favorable time-kill kinetics compared to the first-line MRSA antibiotic, vancomycin, and also conferred significant protection from mortality in a murine model of systemic lethal MRSA infection. These data emphasize the utility of the marine environment as a relatively untapped source of antibiotics against major drug-resistant human pathogens. These studies will also guide future isolation and preclinical development of depsipeptide anti-MRSA compounds from marine-derived actinomycetes. PMID:20339399

  16. PBP-2 Negative Methicillin Resistant Staphylococcus schleiferi Bacteremia from a Prostate Abscess: An Unusual Occurrence

    PubMed Central

    Merchant, Chandni; Villanueva, Daphne-Dominique; Lalani, Ishan; Eng, Margaret; Kang, Yong

    2016-01-01

    Staphylococcus schleiferi subsp. schleiferi is a coagulase-negative Staphylococcus which has been described as a pathogen responsible for various nosocomial infections including bacteremia, brain abscess, and infection of intravenous pacemakers. Recently, such bacteria have been described to be found typically on skin and mucosal surfaces. It is also believed to be a part of the preaxillary human flora and more frequently found in men. It is very similar in its pathogenicity with Staphylococcus aureus group and expresses a fibronectin binding protein. Literature on this pathogen reveals that it commonly causes otitis among dogs because of its location in the auditory meatus of canines. Also, it has strong association with pyoderma in dogs. The prime concern with this organism is the antibiotic resistance and relapse even after appropriate treatment. Very rarely, if any, cases have been reported about prostatic abscess (PA) with this microbe. Our patient had a history of recurrent UTIs and subsequent PA resulting in S. schleiferi bacteremia in contrast to gram negative bacteremia commonly associated with UTI. This organism was found to be resistant to methicillin, in spite of being negative for PBP2, which is a rare phenomenon and needs further studies. PMID:27092283

  17. Detection of methicillin-resistant Staphylococcus aureus in clinical specimens from cystic fibrosis patients by use of chromogenic selective agar.

    PubMed

    Perez, Leandro Reus Rodrigues; Antunes, Ana Lúcia Souza; Bonfanti, Jéssica Weiss; Pinto, Jaqueline Becker; Roesch, Eliane Wurdig; Rodrigues, Diógenes; Dias, Cícero Armídio Gomes

    2012-07-01

    We evaluated the use of a chromogenic selective medium (MRSA ID) as a useful tool for the detection of methicillin-resistant Staphylococcus aureus (MRSA) in cystic fibrosis (CF) patient samples. Fifty-four MRSA isolates were detected by MRSA ID, while only 24/54 (44%) (odds ratio [OR], 2.79; 95% confidence interval [CI], 1.63 to 4.76) were detected by conventional methods. A chromogenic selective medium for MRSA detection may improve its surveillance in CF patients.

  18. Use of BBL CHROMagar MRSA Medium for Identification of Methicillin-Resistant Staphylococcus aureus Directly from Blood Cultures

    PubMed Central

    Pape, John; Wadlin, Jill; Nachamkin, Irving

    2006-01-01

    We evaluated the ability of BBL CHROMagar MRSA medium (Becton Dickinson, Sparks, MD) to identify methicillin-resistant Staphylococcus aureus (MRSA) directly upon subculture from positive blood culture bottles. There were 124 MRSA isolates recovered from blood cultures in the study. BBL CHROMagar MRSA medium was highly sensitive (97.6% [121/124] at 18 to 24 h of incubation and 100% [124/124] at 48 h) and 99.9% specific for identifying MRSA from positive blood cultures. PMID:16825383

  19. Darwinolide, a New Diterpene Scaffold That Inhibits Methicillin-Resistant Staphylococcus aureus Biofilm from the Antarctic Sponge Dendrilla membranosa.

    PubMed

    von Salm, Jacqueline L; Witowski, Christopher G; Fleeman, Renee M; McClintock, James B; Amsler, Charles D; Shaw, Lindsey N; Baker, Bill J

    2016-06-01

    A new rearranged spongian diterpene, darwinolide, has been isolated from the Antarctic Dendroceratid sponge Dendrilla membranosa. Characterized on the basis of spectroscopic and crystallographic analysis, the central seven-membered ring is hypothesized to originate from a ring-expansion of a spongian precursor. Darwinolide displays 4-fold selectivity against the biofilm phase of methicillin-resistant Staphylococcus aureus compared to the planktonic phase and may provide a scaffold for the development of therapeutics for this difficult to treat infection.

  20. Darwinolide, a New Diterpene Scaffold That Inhibits Methicillin-Resistant Staphylococcus aureus Biofilm from the Antarctic Sponge Dendrilla membranosa

    PubMed Central

    2016-01-01

    A new rearranged spongian diterpene, darwinolide, has been isolated from the Antarctic Dendroceratid sponge Dendrilla membranosa. Characterized on the basis of spectroscopic and crystallographic analysis, the central seven-membered ring is hypothesized to originate from a ring-expansion of a spongian precursor. Darwinolide displays 4-fold selectivity against the biofilm phase of methicillin-resistant Staphylococcus aureus compared to the planktonic phase and may provide a scaffold for the development of therapeutics for this difficult to treat infection. PMID:27175857

  1. Species and staphylococcal cassette chromosome mec (SCCmec) diversity among methicillin-resistant non-Staphylococcus aureus staphylococci isolated from pigs.

    PubMed

    Vanderhaeghen, Wannes; Vandendriessche, Stien; Crombé, Florence; Dispas, Marc; Denis, Olivier; Hermans, Katleen; Haesebrouck, Freddy; Butaye, Patrick

    2012-07-01

    While methicillin-resistant Staphylococcus aureus (MRSA) ST398 is known to be widespread in pig farms, few studies have investigated the species diversity and SCCmec types of methicillin-resistant non-S. aureus staphylococci (MRNAS) residing in the nose of pigs. We examined nasal swab samples of 200 pigs originating from 10 Belgian pig farms previously found positive for MRSA ST398. Suspected staphylococcal isolates were subjected to a 16S rRNA-mecA-nuc PCR. Confirmed MRNAS were genotypically identified to the species level and investigated with a SCCmec typing PCR. MRNAS (n=72) were detected on all 10 farms and were carried by 29.5% of the pigs. Seven MRNAS species were found: Staphylococcus epidermidis (38.9%), Staphylococcus sciuri (18.1%), Staphylococcus pasteuri (18.1%), Staphylococcus rostri (12.5%), Staphylococcus warneri (8.3%), Staphylococcus haemolyticus (2.7%) and Staphylococcus hominis (1.4%). SCCmec cassettes were of type IVa (29.2%), type IVc (25%), type III (22.2%), type V (5.6%) or could not be assigned to any of the known types (NT types) (18.1%). Five distinct NT types were found. The predominance of methicillin-resistant S. epidermidis (MRSE) in our samples is remarkable, as MRSE is mainly associated with humans. The finding of three different SCCmec elements (IVa, V, NT type 1) in MRNAS that also prevail or predominate in MRSA ST398 shows that MRNAS might be an important SCCmec reservoir for MRSA in pigs. Yet, the occurrence of multiple other SCCmec types illustrates that further studies are required to understand the presence and spread of SCCmec in methicillin-resistant staphylococci from animals.

  2. Vancomycin-intermediate livestock-associated methicillin-resistant Staphylococcus aureus ST398/t9538 from swine in Brazil

    PubMed Central

    Moreno, Luisa Z; Dutra, Mauricio C; Moreno, Marina; Ferreira, Thais SP; da Silva, Givago FR; Matajira, Carlos EC; Silva, Ana Paula S; Moreno, Andrea M

    2016-01-01

    Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has been mainly related with pig farming, in Europe and North America, with the ST398 as the most commonly identified type of LA-MRSA. Here we present the draft genome of the first vancomycin-intermediate MRSA ST398/t9538 isolated from a swine presenting exudative epidermitis in Brazil. PMID:27759766

  3. Use of the cobas 4800 system for the rapid detection of toxigenic Clostridium difficile and methicillin-resistant Staphylococcus aureus.

    PubMed

    Moure, Raquel; Cañizares, Ángeles; Muíño, María; Lobato, Margarita; Fernández, Ana; Rodríguez, María; Gude, Maria José; Tomás, Maria; Bou, Germán

    2016-01-01

    The new cobas® Cdiff and cobas® MRSA/SA tests were compared with conventional methods for the rapid detection of toxigenic Clostridium difficile and methicillin-resistant Staphylococcus aureus. The final concordance between cobas Cdiff Test and GDH/toxin gene screening was 97.62% and between cobas MRSA/SA Test and chromogenic culture, 91.30%, respectively. PMID:26611812

  4. A model for evaluating topical antimicrobial efficacy against methicillin-resistant Staphylococcus aureus biofilms in superficial murine wounds.

    PubMed

    Roche, Eric D; Renick, Paul J; Tetens, Shannon P; Carson, Dennis L

    2012-08-01

    A wound biofilm model was created by adapting a superficial infection model. Partial-thickness murine wounds were inoculated with methicillin-resistant Staphylococcus aureus (MRSA). Dense biofilm communities developed at the wound surface after 24 h as demonstrated by microscopy and quantitative microbiology. Common topical antimicrobial agents had reduced efficacy when treatment was initiated 24 h after inoculation compared to 4 h after inoculation. This model provides a rapid in vivo test for new agents to treat wound biofilm infections.

  5. Staphylococcal cassette chromosome mec elements in methicillin-resistant coagulase-negative staphylococci from a Brazilian neonatal care unit.

    PubMed

    Salgueiro, Vivian Carolina; Azevedo, Milena Borgo; Iorio, Natalia Lopes Pontes; Amorim, Efigênia de Lourdes Teixeira; dos Santos, Kátia Regina Netto

    2014-10-01

    To characterize 46 methicillin-resistant coagulase-negative staphylococci from Brazilian neonates, we investigated their SCCmec type, susceptibility and clonality. Staphylococcus epidermidis and Staphylococcus haemolyticus were the prevalent species. SCCmec types III or IV were detected in 53.3% S. epidermidis, whereas 63.6% S. haemolyticus were nontypeable. Despite the diversity, specific clones carried specific SCCmec elements, highlighting that effective typing can help in epidemiological analysis. PMID:25037043

  6. β-Lactam Resistance in Methicillin-Resistant Staphylococcus aureus USA300 Is Increased by Inactivation of the ClpXP Protease

    PubMed Central

    Bæk, Kristoffer T.; Gründling, Angelika; Mogensen, René G.; Thøgersen, Louise; Petersen, Andreas; Paulander, Wilhelm

    2014-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) has acquired the mecA gene encoding a peptidoglycan transpeptidase, penicillin binding protein 2a (PBP2a), which has decreased affinity for β-lactams. Quickly spreading and highly virulent community-acquired (CA) MRSA strains recently emerged as a frequent cause of infection in individuals without exposure to the health care system. In this study, we found that the inactivation of the components of the ClpXP protease substantially increased the β-lactam resistance level of a CA-MRSA USA300 strain, suggesting that the proteolytic activity of ClpXP controls one or more pathways modulating β-lactam resistance. These pathways do not involve the control of mecA expression, as the cellular levels of PBP2a were unaltered in the clp mutants. An analysis of the cell envelope properties of the clpX and clpP mutants revealed a number of distinct phenotypes that may contribute to the enhanced β-lactam tolerance. Both mutants displayed significantly thicker cell walls, increased peptidoglycan cross-linking, and altered composition of monomeric muropeptide species compared to those of the wild types. Moreover, changes in Sle1-mediated peptidoglycan hydrolysis and altered processing of the major autolysin Atl were observed in the clp mutants. In conclusion, the results presented here point to an important role for the ClpXP protease in controlling cell wall metabolism and add novel insights into the molecular factors that determine strain-dependent β-lactam resistance. PMID:24867990

  7. β-Lactam resistance in methicillin-resistant Staphylococcus aureus USA300 is increased by inactivation of the ClpXP protease.

    PubMed

    Bæk, Kristoffer T; Gründling, Angelika; Mogensen, René G; Thøgersen, Louise; Petersen, Andreas; Paulander, Wilhelm; Frees, Dorte

    2014-08-01

    Methicillin-resistant Staphylococcus aureus (MRSA) has acquired the mecA gene encoding a peptidoglycan transpeptidase, penicillin binding protein 2a (PBP2a), which has decreased affinity for β-lactams. Quickly spreading and highly virulent community-acquired (CA) MRSA strains recently emerged as a frequent cause of infection in individuals without exposure to the health care system. In this study, we found that the inactivation of the components of the ClpXP protease substantially increased the β-lactam resistance level of a CA-MRSA USA300 strain, suggesting that the proteolytic activity of ClpXP controls one or more pathways modulating β-lactam resistance. These pathways do not involve the control of mecA expression, as the cellular levels of PBP2a were unaltered in the clp mutants. An analysis of the cell envelope properties of the clpX and clpP mutants revealed a number of distinct phenotypes that may contribute to the enhanced β-lactam tolerance. Both mutants displayed significantly thicker cell walls, increased peptidoglycan cross-linking, and altered composition of monomeric muropeptide species compared to those of the wild types. Moreover, changes in Sle1-mediated peptidoglycan hydrolysis and altered processing of the major autolysin Atl were observed in the clp mutants. In conclusion, the results presented here point to an important role for the ClpXP protease in controlling cell wall metabolism and add novel insights into the molecular factors that determine strain-dependent β-lactam resistance.

  8. Identification and characterization of methicillin-resistant Staphylococcus aureus (MRSA) from Austrian companion animals and horses.

    PubMed

    Loncaric, Igor; Künzel, Frank; Licka, Theresia; Simhofer, Hubert; Spergser, Joachim; Rosengarten, Renate

    2014-01-31

    The aim of this study was to investigate the antimicrobial resistance, resistance gene patterns and genetic relatedness of a collection of Austrian methicillin-resistant Staphylococcus aureus (MRSA) isolates from companion animals and horses. A total of 89 non-repetitive MRSA isolates collected during routine veterinary microbiological examinations from April 2004 to the end of 2012, and one isolate from 2013 were used for this study. The presence of mecA and other resistance genes was confirmed by PCR. Isolates were genotyped by spa typing, two multiple-locus variable-number tandem repeat analyses (MLVA) analyses, SCCmec typing and multilocus sequence typing (MLST). PCR targeting Panton-Valentine leukocidin (PVL) and detection of staphylococcal enterotoxins (SE), toxic shock syndrome toxin (TSST) was performed using PCR assays. Antimicrobial susceptibility testing was performed. Five sequence types (STs-ST398, ST254, ST22, ST5 and ST1), SCCmec types II, IVa, V, and non-type-abele, 8 spa-types (t003, t011, t036, t127, t386, t1348, and t4450), and two isolates could not be assigned, 21 MLVA-14Orsay types Multiplex-PCR MLVA (mMLVA) displayed 17 different MLVA types. The present study is the most comprehensive dealing with MRSA from Austrian companion animals and horses. The results confirm that MRSA ST398 is present in a wide range of animal species and is predominant especially in horses. In other companion animals it is unclear whether the infections with the different MRSA isolates investigated in the present study truly represents a rare phenomenon or may be an emerging problem in companion animals.

  9. Methicillin-Resistant Staphylococcus aureus from Brazilian Dairy Farms and Identification of Novel Sequence Types.

    PubMed

    Oliveira, C J B; Tiao, N; de Sousa, F G C; de Moura, J F P; Santos Filho, L; Gebreyes, W A

    2016-03-01

    The aim of this study was to investigate the phenotypic and genotypic diversity and anti-microbial resistance among staphylococci of dairy herds that originated from Paraiba State, north-eastern Brazil, a region where such studies are rare. Milk samples (n = 552) were collected from 15 dairy farms. Isolates were evaluated for anti-microbial susceptibility by Kirby-Bauer disc diffusion method. Confirmation of methicillin-resistant Staphylococcus aureus (MRSA) was performed using multiplex PCR targeting mecA and nuc genes in addition to phenotypic assay based on PBP-2a latex agglutination. Clonal relatedness of isolates was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) genotyping. Staphylococci were detected in 269 (49%) of the samples. Among these, 65 (24%) were S. aureus. The remaining 204 isolates were either coagulase-negative staphylococci (n = 188; 70%) or coagulase positive other than S. aureus (n = 16; 6%). Staphylococci were cultured in seven (35%) of the 20 hand swab samples, from which five isolates were S. aureus. The isolates were most commonly resistant against penicillin (43%), ampicillin (38%) and oxacillin (27%). The gene mecA was detected in 21 S. aureus from milk and in one isolate from a milker's hand. None of the isolates were resistant to vancomycin. PFGE findings showed high clonal diversity among the isolates. Based on MLST, we identified a total of 11 different sequence types (STs 1, 5, 6, 83, 97, 126, 1583, 1622, 1623, 1624 and 1625) with four novel STs (ST1622-ST1625). The findings show that MRSA is prevalent in milk from semi-extensive dairy cows in north-eastern Brazil, and further investigation on its extent in various types of milk production systems and the farm-to-table continuum is warranted.

  10. Chlorhexidine and mupirocin susceptibilities in methicillin-resistant Staphylococcus aureus isolates from bacteraemia and nasal colonisation.

    PubMed

    Muñoz-Gallego, Irene; Infiesta, Lucia; Viedma, Esther; Perez-Montarelo, Dafne; Chaves, Fernando

    2016-03-01

    Chlorhexidine and mupirocin have been increasingly used in healthcare facilities to eradicate methicillin-resistant Staphylococcus aureus (MRSA) carriage. The aim of this study was to determine the prevalence and mechanisms of chlorhexidine and mupirocin resistance in MRSA from invasive infections and colonisation. MRSA isolates obtained from blood and nasal samples between 2012 and 2014 were analysed. Susceptibility to mupirocin was determined by disk diffusion and Etest and susceptibility to chlorhexidine by broth microdilution. The presence of mupA and qac (A/B and C) genes was investigated by PCR. Molecular typing was performed in high-level mupirocin-resistant (HLMR) isolates. Mupirocin resistance was identified in 15.6% of blood isolates (10.9% HLMR) and 15.1% of nasal isolates (12.0% HLMR). Presence of the mupA gene was confirmed in all HLMR isolates. For blood isolates, chlorhexidine minimum inhibitory concentrations (MICs) ranged from ≤0.125 to 4mg/L and minimum bactericidal concentrations (MBCs) from ≤0.125 to 8mg/L. In nasal isolates, chlorhexidine MICs and MBCs ranged from ≤0.125 to 2mg/L. The qacA/B gene was detected in 2.2% of MRSA isolates (chlorhexidine MIC range 0.25-2mg/L) and the qacC gene in 8.2% (chlorhexidine MIC range ≤0.125-1mg/L). The prevalence of qacC was 18.9% in HLMR isolates and 3.6% in mupirocin-susceptible isolates (P=0.009). Most of the HLMR isolates (97.1%) belonged to ST125 clone. These results suggest that chlorhexidine has a higher potential to prevent infections caused by MRSA. In contrast, mupirocin treatment should be used cautiously to avoid the spread of HLMR MRSA. PMID:27436397

  11. Antibacterial synergy between rosmarinic acid and antibiotics against methicillin-resistant Staphylococcus aureus

    PubMed Central

    Ekambaram, Sanmuga Priya; Perumal, Senthamil Selvan; Balakrishnan, Ajay; Marappan, Nathiya; Gajendran, Sabari Srinivasan; Viswanathan, Vinodhini

    2016-01-01

    Aim/Background: Medicinal plants have ability to resist microorganisms by synthesizing secondary metabolites such as phenols. Rosmarinic acid (RA) is a phenylpropanoid widely distributed in plants and well known as therapeutic and cosmetic agent. Methicillin-resistant Staphylococcus aureus (MRSA) which is resistant to all kinds of β-lactams, threatens even most potent antibiotics. To improve the efficiency of antibiotics against multi-drug resistant bacteria and to reduce the antibiotic dose, the antibacterial activity and the synergistic effect of RA with standard antibiotics against S. aureus and MRSA was investigated. Materials and Methods: Antibacterial activity of RA against S. aureus and a clinical isolate of MRSA was evaluated by agar well diffusion method. Minimum inhibitory concentration (MIC) of RA was determined by broth dilution method. Synergism of RA with various antibiotics against S. aureus and MRSA was studied by broth checkerboard method and time-kill kinetic assay. Effect of RA on microbial surface components recognizing adhesive matrix molecules (MSCRAMM’s) of S. aureus and MRSA was studied using sodium dodecyl sulfate - polyacrylamide gel electrophoresis. Results: MIC of RA was found to be 0.8 and 10 mg/ml against S. aureus and MRSA, respectively. RA was synergistic with vancomycin, ofloxacin, and amoxicillin against S. aureus and only with vancomycin against MRSA. The time-kill analysis revealed that synergistic combinations were a more effective than individual antibiotics. MSCRAMM’s protein expression of S. aureus and MRSA was markedly suppressed by RA + vancomycin combination rather than RA alone. Conclusion: The synergistic effects of RA with antibiotics were observed against S. aureus and MRSA. RA showed inhibitory effect on the surface proteins MSCRAMM’s. Even though RA was shown to exhibit a synergistic effect with antibiotics, the MIC was found to be higher. Thus, further studies on increasing the efficacy of RA can develop it

  12. Methicillin-Resistant Staphylococcus aureus from Brazilian Dairy Farms and Identification of Novel Sequence Types.

    PubMed

    Oliveira, C J B; Tiao, N; de Sousa, F G C; de Moura, J F P; Santos Filho, L; Gebreyes, W A

    2016-03-01

    The aim of this study was to investigate the phenotypic and genotypic diversity and anti-microbial resistance among staphylococci of dairy herds that originated from Paraiba State, north-eastern Brazil, a region where such studies are rare. Milk samples (n = 552) were collected from 15 dairy farms. Isolates were evaluated for anti-microbial susceptibility by Kirby-Bauer disc diffusion method. Confirmation of methicillin-resistant Staphylococcus aureus (MRSA) was performed using multiplex PCR targeting mecA and nuc genes in addition to phenotypic assay based on PBP-2a latex agglutination. Clonal relatedness of isolates was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) genotyping. Staphylococci were detected in 269 (49%) of the samples. Among these, 65 (24%) were S. aureus. The remaining 204 isolates were either coagulase-negative staphylococci (n = 188; 70%) or coagulase positive other than S. aureus (n = 16; 6%). Staphylococci were cultured in seven (35%) of the 20 hand swab samples, from which five isolates were S. aureus. The isolates were most commonly resistant against penicillin (43%), ampicillin (38%) and oxacillin (27%). The gene mecA was detected in 21 S. aureus from milk and in one isolate from a milker's hand. None of the isolates were resistant to vancomycin. PFGE findings showed high clonal diversity among the isolates. Based on MLST, we identified a total of 11 different sequence types (STs 1, 5, 6, 83, 97, 126, 1583, 1622, 1623, 1624 and 1625) with four novel STs (ST1622-ST1625). The findings show that MRSA is prevalent in milk from semi-extensive dairy cows in north-eastern Brazil, and further investigation on its extent in various types of milk production systems and the farm-to-table continuum is warranted. PMID:26178302

  13. Characterization of methicillin-resistant Staphylococcus pseudintermedius isolated from dogs and cats.

    PubMed

    Bardiau, Marjorie; Yamazaki, Kazuko; Ote, Isabelle; Misawa, Naoaki; Mainil, Jacques G

    2013-07-01

    The aim of this study was to explore the presence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in a collection of S. pseudintermedius strains isolated from dogs and cats with dermatitis in Japan and to compare their genotypic and phenotypic characteristics. Clonal relationships were determined by pulse field gel electrophoresis (PFGE), staphylococcal chromosomal cassette mec (SCCmec) typing, and multilocus sequence typing (MLST). Biofilm formation assay was performed using safranin staining in microplates. Three virulence genes coding for S. intermedius exfoliative toxin and Panton-Valentine leukocidin (siet, lukS-PV and lukF-PV) were searched for in a collection of strains. Antimicrobial resistance against 15 antibiotics was studied by a disc diffusion method. Twenty-seven MRSP were isolated. According to PFGE results the isolates were not closely related except for a few strains. MLST showed that the strains belonged to five groups, ST71 and ST26 being the two most prevalent. Three types of SCCmec (II, II-III and V) were identified. All isolates were siet-positive but PVL-negative. Most strains (except for two) produced strong biofilm in tryptic soy broth with glucose. Seventy-eight percent of the isolates were resistant or intermediate to twelve or more antibiotics. Our study demonstrates that the ST71 lineage is widespread in Japan and that ST26 could represent an emerging lineage. Moreover, most of our strains are capable of forming strong biofilm and possess siet gene, two virulence characteristics that probably help the bacteria to persist and spread. Finally, our MRSP strains show a strong resistance profile to antibiotics commonly used in veterinary medicine.

  14. Identification and characterization of potential drug targets by subtractive genome analyses of methicillin resistant Staphylococcus aureus.

    PubMed

    Uddin, Reaz; Saeed, Kiran

    2014-02-01

    Methicillin resistant Staphylococcus aureus (MRSA) causes serious infections in humans and becomes resistant to a number of antibiotics. Due to the emergence of antibiotic resistance strains, there is an essential need to develop novel drug targets to address the challenge of multidrug-resistant bacteria. In current study, the idea was to utilize the available genome or proteome in a subtractive genome analyses protocol to identify drug targets within two of the MRSA types, i.e., MRSA ST398 and MRSA 252. Recently, the use of subtractive genomic approaches helped in the identification and characterization of novel drug targets of a number of pathogens. Our protocol involved a similarity search between pathogen and host, essentiality study using the database of essential genes, metabolic functional association study using Kyoto Encyclopedia of Genes and Genomes database (KEGG), cellular membrane localization analysis and Drug Bank database. Functional family characterizations of the identified non homologous hypothetical essential proteins were done by SVMProt server. Druggability potential of each of the identified drug targets was also evaluated by Drug Bank database. Moreover, metabolic pathway analysis of the identified druggable essential proteins with KEGG revealed that the identified proteins are participating in unique and essential metabolic pathways amongst MRSA strains. In short, the complete proteome analyses by the use of advanced computational tools, databases and servers resulted in identification and characterization of few nonhomologous/hypothetical and essential proteins which are not homologous to the host genome. Therefore, these non-homologous essential targets ensure the survival of the pathogen and hence can be targeted for drug discovery.

  15. Identification and methicillin resistance of coagulase-negative staphylococci isolated from nasal cavity of healthy horses.

    PubMed

    Karakulska, Jolanta; Fijałkowski, Karol; Nawrotek, Paweł; Pobucewicz, Anna; Poszumski, Filip; Czernomysy-Furowicz, Danuta

    2012-06-01

    The aim of this study was an analysis of the staphylococcal flora of the nasal cavity of 42 healthy horses from 4 farms, along with species identification of CoNS isolates and determination of resistance to 18 antimicrobial agents, particularly phenotypic and genotypic methicillin resistance. From the 81 swabs, 87 staphylococci were isolated. All isolates possessed the gap gene but the coa gene was not detected in any of these isolates. Using PCR-RFLP of the gap gene, 82.8% of CoNS were identified: S. equorum (14.9%), S. warneri (14.9%), S. sciuri (12.6%), S. vitulinus (12.6%), S. xylosus (11.5%), S. felis (5.7%), S. haemolyticus (3.4%), S. simulans (3.4%), S. capitis (1.1%), S. chromogenes (1.1%), and S. cohnii subsp. urealyticus (1.1%). To our knowledge, this was the first isolation of S. felis from a horse. The species identity of the remaining Staphylococcus spp. isolates (17.2%) could not be determined from the gap gene PCR-RFLP analysis and 16S rRNA gene sequencing data. Based on 16S-23S intergenic transcribed spacer PCR, 11 different ITS-PCR profiles were identified for the 87 analyzed isolates. Results of API Staph were consistent with molecular identification of 17 (19.5%) isolates. Resistance was detected to only 1 or 2 of the 18 antimicrobial agents tested in the 17.2% CoNS isolates, including 6.9% MRCoNS. The mecA gene was detected in each of the 5 (5.7%) phenotypically cefoxitin-resistant isolates and in 12 (13.8%) isolates susceptible to cefoxitin. In total, from 12 horses (28.6%), 17 (19.5%) MRCoNS were isolated. The highest percentage of MRCoNS was noted among S. sciuri isolates (100%). PMID:22752908

  16. TarO-specific inhibitors of wall teichoic acid biosynthesis restore β-lactam efficacy against methicillin-resistant staphylococci.

    PubMed

    Lee, Sang Ho; Wang, Hao; Labroli, Marc; Koseoglu, Sandra; Zuck, Paul; Mayhood, Todd; Gill, Charles; Mann, Paul; Sher, Xinwei; Ha, Sookhee; Yang, Shu-Wei; Mandal, Mihir; Yang, Christine; Liang, Lianzhu; Tan, Zheng; Tawa, Paul; Hou, Yan; Kuvelkar, Reshma; DeVito, Kristine; Wen, Xiujuan; Xiao, Jing; Batchlett, Michelle; Balibar, Carl J; Liu, Jenny; Xiao, Jianying; Murgolo, Nicholas; Garlisi, Charles G; Sheth, Payal R; Flattery, Amy; Su, Jing; Tan, Christopher; Roemer, Terry

    2016-03-01

    The widespread emergence of methicillin-resistant Staphylococcus aureus (MRSA) has dramatically eroded the efficacy of current β-lactam antibiotics and created an urgent need for new treatment options. We report an S. aureus phenotypic screening strategy involving chemical suppression of the growth inhibitory consequences of depleting late-stage wall teichoic acid biosynthesis. This enabled us to identify early-stage pathway-specific inhibitors of wall teichoic acid biosynthesis predicted to be chemically synergistic with β-lactams. We demonstrated by genetic and biochemical means that each of the new chemical series discovered, herein named tarocin A and tarocin B, inhibited the first step in wall teichoic acid biosynthesis (TarO). Tarocins do not have intrinsic bioactivity but rather demonstrated potent bactericidal synergy in combination with broad-spectrum β-lactam antibiotics against diverse clinical isolates of methicillin-resistant staphylococci as well as robust efficacy in a murine infection model of MRSA. Tarocins and other inhibitors of wall teichoic acid biosynthesis may provide a rational strategy to develop Gram-positive bactericidal β-lactam combination agents active against methicillin-resistant staphylococci.

  17. [Methicillin resistance detection in Staphylococcus aureus: comparison between conventional methods and MRSA-Screen latex agglutination technique].

    PubMed

    Soloaga, R; Corso, A; Gagetti, P; Faccone, D; Galas, M

    2004-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen that has emerged over the last four decades, causing both nosocomial and community-acquired infections. Rapid and accurate detection of methicillin resistance in S. aureus is important for the use of appropriate antimicrobial therapy and for the control of nosocomial spread of MRSA strains. We evaluated the efficiency of conventional methods for detection of methicillin resistance such as the disk diffusion, agar dilution, oxacillin agar screen test, and the latex agglutination test MRSA-Screen latex, in 100 isolates of S. aureus, 79 mecA positive and 21 mecA negative. The MRSA-Screen latex (Denka Seiken, Niigata, Japón), is a latex agglutination method that detects the presence of PLP-2a, product of mecA gene in S. aureus. The PCR of the mecA gene was used as the "gold standard" for the evaluation of the different methods tested. The percentages of sensitivity and specificity were as follows: disk difusión 97 and 100%, agar dilution 97 and 95%, oxacillin agar screen test 100 and 100%, and MRSA-Screen latex, 100 and 100 %. All methods presented high sensitivity and specificity, but MRSA-Screen latex had the advantage of giving a reliable result, equivalent to PCR, in only 15 minutes.

  18. Potential Mechanism of Action of 3'-Demethoxy-6-O-demethyl-isoguaiacin on Methicillin Resistant Staphylococcus aureus.

    PubMed

    Favela-Hernández, Juan Manuel J; Clemente-Soto, Aldo F; Balderas-Rentería, Isaías; Garza-González, Elvira; Camacho-Corona, María del Rayo

    2015-07-08

    Bacterial infections represent one of the main threats to global public health. One of the major causative agents associated with high morbidity and mortality infections in hospitals worldwide is methicillin-resistant Staphylococcus aureus. Therefore, there is a need to develop new antibacterial agents to treat these infections, and natural products are a rich source of them. In previous studies, we reported that lignan 3'-demethoxy-6-O-demethylisoguaiacin, isolated and characterized from Larrea tridentate, showed the best activity towards methicillin-resistant S. aureus. Thus, the aim of this study was to determine the potential molecular mechanism of the antibacterial activity of 3'-demethoxy-6-O-demethylisoguaiacin against methicillin-resistant S. aureus using microarray technology. Results of microarray genome expression were validated by real-time polymerase chain reaction (RT-PCR). The genetic profile expression results showed that lignan 3'-demethoxy-6-O-demethylisoguaiacin had activity on cell membrane affecting proteins of the ATP-binding cassette (ABC) transport system causing bacteria death. This molecular mechanism is not present in any antibacterial commercial drug and could be a new target for the development of novel antibacterial agents.

  19. [The use of oxacillin and cefoxitin disk-diffusion method and PCR for the identification methicillin-resistant Staphylococcus epidermidis].

    PubMed

    Budzyńska, Anna; Kaczmarek, Agnieszka; Mikołajczyk, Dorota; Gospodarek, Eugenia

    2007-01-01

    Methicillin-resistant S. epidermidis are recognized as one of the most important nosocomial infections. Because of the different expression level of mecA gene which is under regulatory genes control, detection of methicillin resistance by phenotypic methods may leads to false negative or false positive results. The aim of this study was to estimate effectiveness of MRSE strains identification using oxacillin (1 microg) and cefoxitin (30 microg) disk-diffusion method in comparison with PCR, considered as a "gold standard". The analysis of 120 strains isolated from clinical materials of patients of the University Hospital at the L. Rydygier Collegium Medicum in Bydgoszcz, University of Nicolaus Copernicus in Toruń indicated high degree of correlation between phenotypic methods with taken disks. Results consistency of detecting methicillin resistance between oxacillin disk diffusion method and PCR concerned 95% strains. In case of cefoxitin 4,2% S. epidermidis strains detected phenotypically as MSSE were mecA-positive. Our results show that disk-diffusion method with disks mentioned above is characterized by comparable specificity and sensitivity amounted 90,8% and 100% for oxacillin and 92,3% and 100% for cefoxitin respectively.

  20. TarO-specific inhibitors of wall teichoic acid biosynthesis restore β-lactam efficacy against methicillin-resistant staphylococci.

    PubMed

    Lee, Sang Ho; Wang, Hao; Labroli, Marc; Koseoglu, Sandra; Zuck, Paul; Mayhood, Todd; Gill, Charles; Mann, Paul; Sher, Xinwei; Ha, Sookhee; Yang, Shu-Wei; Mandal, Mihir; Yang, Christine; Liang, Lianzhu; Tan, Zheng; Tawa, Paul; Hou, Yan; Kuvelkar, Reshma; DeVito, Kristine; Wen, Xiujuan; Xiao, Jing; Batchlett, Michelle; Balibar, Carl J; Liu, Jenny; Xiao, Jianying; Murgolo, Nicholas; Garlisi, Charles G; Sheth, Payal R; Flattery, Amy; Su, Jing; Tan, Christopher; Roemer, Terry

    2016-03-01

    The widespread emergence of methicillin-resistant Staphylococcus aureus (MRSA) has dramatically eroded the efficacy of current β-lactam antibiotics and created an urgent need for new treatment options. We report an S. aureus phenotypic screening strategy involving chemical suppression of the growth inhibitory consequences of depleting late-stage wall teichoic acid biosynthesis. This enabled us to identify early-stage pathway-specific inhibitors of wall teichoic acid biosynthesis predicted to be chemically synergistic with β-lactams. We demonstrated by genetic and biochemical means that each of the new chemical series discovered, herein named tarocin A and tarocin B, inhibited the first step in wall teichoic acid biosynthesis (TarO). Tarocins do not have intrinsic bioactivity but rather demonstrated potent bactericidal synergy in combination with broad-spectrum β-lactam antibiotics against diverse clinical isolates of methicillin-resistant staphylococci as well as robust efficacy in a murine infection model of MRSA. Tarocins and other inhibitors of wall teichoic acid biosynthesis may provide a rational strategy to develop Gram-positive bactericidal β-lactam combination agents active against methicillin-resistant staphylococci. PMID:26962156

  1. Cell shunt resistance and photovoltaic module performance

    SciTech Connect

    McMahon, T.J.; Basso, T.S.; Rummel, S.R.

    1996-09-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, they verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. They discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  2. Resource burden associated with contact precautions for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus: the patient access managers' perspective.

    PubMed

    Shenoy, Erica S; Walensky, Rochelle P; Lee, Hang; Orcutt, Benjamin; Hooper, David C

    2012-08-01

    We surveyed patient access managers on the impact of contact precautions (CP) for methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE) on time to bed assignment, and we investigated the factors influencing infection control policies allowing for discontinuation of CP. The majority of respondents reported an increase in time to bed assignment for patients with a history of MRSA and/or VRE infection or colonization. PMID:22759555

  3. Evaluation of small molecule SecA inhibitors against methicillin-resistant Staphylococcus aureus.

    PubMed

    Jin, Jinshan; Cui, Jianmei; Chaudhary, Arpana Sagwal; Hsieh, Ying-Hsin; Damera, Krishna; Zhang, Hao; Yang, Hsiuchin; Wang, Binghe; Tai, Phang C

    2015-11-01

    Due to the emergence and rapid spread of drug resistance in bacteria, there is an urgent need for the development of novel antimicrobials. SecA, a key component of the general bacterial secretion system required for viability and virulence, is an attractive antimicrobial target. Earlier we reported that systematical dissection of a SecA inhibitor, Rose Bengal (RB), led to the development of novel small molecule SecA inhibitors active against Escherichia coli and Bacillus subtilis. In this study, two potent RB analogs were further evaluated for activities against methicillin-resistant Staphylococcus aureus (MRSA) strains and for their mechanism of actions. These analogs showed inhibition on the ATPase activities of S. aureus SecA1 (SaSecA1) and SecA2 (SaSecA2), and inhibition of SaSecA1-dependent protein-conducting channel. Moreover, these inhibitors reduce the secretion of three toxins from S. aureus and exert potent bacteriostatic effects against three MRSA strains. Our best inhibitor SCA-50 showed potent concentration-dependent bactericidal activity against MRSA Mu50 strain and very importantly, 2-60 fold more potent inhibitory effect on MRSA Mu50 than all the commonly used antibiotics including vancomycin, which is considered the last resort option in treating MRSA-related infections. Protein pull down experiments further confirmed SaSecA1 as a target. Deletion or overexpression of NorA and MepA efflux pumps had minimal effect on the antimicrobial activities against S. aureus, indicating that the effects of SecA inhibitors were not affected by the presence of these efflux pumps. Our studies show that these small molecule analogs target SecA functions, have potent antimicrobial activities, reduce the secretion of toxins, and have the ability to overcome the effect efflux pumps, which are responsible for multi-drug resistance. Thus, targeting SecA is an attractive antimicrobial strategy against MRSA.

  4. Genetic environment and stability of cfr in methicillin-resistant Staphylococcus aureus CM05.

    PubMed

    Locke, Jeffrey B; Rahawi, Shahad; Lamarre, Jacqueline; Mankin, Alexander S; Shaw, Karen Joy

    2012-01-01

    The Cfr methyltransferase confers resistance to many 50S ribosomal subunit-targeted antibiotics, including linezolid (LZD), via methylation of the 23S rRNA base A2503 in the peptidyl transferase center. Methicillin-resistant Staphylococcus aureus strain CM05 is the first clinical isolate documented to carry cfr. While cfr is typically plasmid borne, in CM05 it is located on the chromosome and is coexpressed with ermB as part of the mlr operon. Here we evaluated the chromosomal locus, association with mobile genetic elements, and stability of the cfr insertion region in CM05. The cfr-containing mlr operon is located within a 15.5-kb plasmid-like insertion into 23S rRNA allele 4. The region surrounding the cfr gene has a high degree of sequence similarity to the broad-host-range toxin/antitoxin multidrug resistance plasmid pSM19035, including a second ermB gene downstream of the mlr locus and istAS-istBS. Analysis of several individual CM05 colonies revealed two distinct populations for which LZD MICs were either 8 or 2 μg/ml. In the LZD(s) colonies (designated CM05Δ), a recombination event involving the two ermB genes had occurred, resulting in the deletion of cfr and the 3' flanking region (cfr-istAS-istBS-ermB). The fitness advantage of CM05Δ over CM05 (though not likely due to the cfr deletion itself) results in the predominance of CM05Δ in the absence of selective pressure. Minicircles resulting from the ermB recombination event and the novel association of cfr with the pSM19035 plasmid system support the potential for the continued dissemination of cfr.

  5. Vancomycin Tolerant, Methicillin-Resistant Staphylococcus aureus Reveals the Effects of Vancomycin on Cell Wall Thickening

    PubMed Central

    Cázares-Domínguez, Vicenta; Cruz-Córdova, Ariadnna; Ochoa, Sara A.; Escalona, Gerardo; Arellano-Galindo, José; Rodríguez-Leviz, Alejandra; Hernández-Castro, Rigoberto; López-Villegas, Edgar O.; Xicohtencatl-Cortes, Juan

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important opportunistic pathogen that causes both healthcare- and community-acquired infections. An increase in the incidence of these infections may lead to a substantial change in the rate of vancomycin usage. Incidence of reduced susceptibility to vancomycin has been increasing worldwide for the last few years, conferring different levels of resistance to vancomycin as well as producing changes in the cell wall structure. The aim of the present study was to determine the effect of vancomycin on cell wall thickening in clinical isolates of vancomycin-tolerant (VT) MRSA obtained from pediatric patients. From a collection of 100 MRSA clinical isolates from pediatric patients, 12% (12/100) were characterized as VT-MRSA, and from them, 41.66% (5/12) exhibited the heterogeneous vancomycin-intermediate S. aureus (hVISA) phenotype. Multiplex-PCR assays revealed 66.66% (8/12), 25% (3/12), and 8.33% (1/12) of the VT-MRSA isolates were associated with agr group II, I, and III polymorphisms, respectively; the II-mec gene was amplified from 83.3% (10/12) of the isolates, and the mecIVa gene was amplified from 16.66% (2/12) of the isolates. Pulsed field electrophoresis (PFGE) fingerprint analysis showed 62% similarity among the VT-MRSA isolates. Thin transverse sections analyzed by transmission electron microscopy (TEM) revealed an average increase of 24 nm (105.55%) in the cell wall thickness of VT-MRSA compared with untreated VT-MRSA isolates. In summary, these data revealed that the thickened cell walls of VT-MRSA clinical isolates with agr type II and SCCmec group II polymorphisms are associated with an adaptive resistance to vancomycin. PMID:25793280

  6. Frequency of Aminoglycoside-Resistance Genes in Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates from Hospitalized Patients

    PubMed Central

    Mahdiyoun, Seyed Mohsen; Kazemian, Hossein; Ahanjan, Mohammad; Houri, Hamidreza; Goudarzi, Mehdi

    2016-01-01

    Background Staphylococcus aureus is one of the most important causative agents in community- and hospital-acquired infections. Aminoglycosides are powerful bactericidal drugs that are often used in combination with beta-lactams or glycopeptides to treat staphylococcal infections. Objectives The main objective of the present study was to determine the prevalence of aminoglycoside resistance among methicillin-resistant Staphylococcus aureus (MRSA) isolates in hospitalized patients in Sari and Tehran, Iran. Methods In this study, 174 MRSA strains isolated from different clinical samples, such as blood, sputum, tracheal exudates, bronchus, pleura, urine, wounds, and catheters, were collected from hospitalized patients in Tehran and Sari during 2014. Antibiotic susceptibility testing was performed against nine antibiotics with the Kirby-Bauer disk diffusion method according to CLSI guidelines. The MRSA strains were examined with oxacillin and cefoxitin disks. MRSA was then validated by detection of the mecA gene. PCR was used to evaluate the prevalence of the aminoglycoside-resistance genes aac (6’)-Ie/aph (2”), aph (3’)-IIIa, and ant (4’) among the MRSA isolates. Results The results of drug susceptibility testing showed that the highest rate of resistance was against erythromycin in Tehran (84.4%) and gentamicin (71.7%) in Sari. All isolates were sensitive to vancomycin, and all strains harbored the mecA gene. The aac (6’)-Ie/aph (2”), aph (3’)-IIIa, and ant (4’)-Ia genes were detected among 134 (77%), 119 (68.4%), and 122 (70.1%) of the isolates, respectively. Conclusions The present study showed a high prevalence of aminoglycoside-resistance genes among MRSA isolates in two cities in Iran. PMID:27800135

  7. Rifampicin-fosfomycin coating for cementless endoprostheses: antimicrobial effects against methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Alt, Volker; Kirchhof, Kristin; Seim, Florian; Hrubesch, Isabelle; Lips, Katrin S; Mannel, Henrich; Domann, Eugen; Schnettler, Reinhard

    2014-10-01

    New strategies to decrease infection rates in cementless arthroplasty are needed, especially in the context of the growing incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections. The purpose of this study was to investigate the antimicrobial activity of a rifampicin-fosfomycin coating against methicillin-sensitive Staphylococcus aureus (MSSA) and MRSA in a rabbit infection prophylaxis model. Uncoated or rifampicin-fosfomycin-coated K-wires were inserted into the intramedullary canal of the tibia in rabbits and contaminated with an inoculation dose of 10(5) or 10(6) colony-forming units of MSSA EDCC 5055 in study 1 and MRSA T6625930 in study 2, respectively. After 28days the animals were killed and clinical, histological and microbiological assessment, including pulse-field gel electrophoresis, was conducted. Positive culture growth in agar plate testing and/or clinical signs and/or histological signs were defined positive for infection. Statistical evaluation was performed using Fisher's exact test. Both studies showed a statistically significant reduction of infection rates for rifampicin-fosfomycin-coated implants compared to uncoated K-wires (P=0.015). In both studies none of the 12 animals that were treated with a rifampicin-fosfomycin-coated implant showed clinical signs of infection or a positive agar plate testing result. In both studies, one animal of the coating group showed the presence of sporadic bacteria with concomitant inflammatory signs in histology. The control groups in both studies exhibited an infection rate of 100% with clear clinical signs of infection and positive culture growth in all animals. In summary, the rifampicin-fosfomycin-coating showed excellent antimicrobial activity against both MSSA and MRSA, and therefore warrants further clinical testing.

  8. Clonal Complexes and Diversity of Exotoxin Gene Profiles in Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Isolates from Patients in a Spanish Hospital▿

    PubMed Central

    Argudín, M. A.; Mendoza, M. C.; Méndez, F. J.; Martín, M. C.; Guerra, B.; Rodicio, M. R.

    2009-01-01

    Molecular epidemiology studies have allowed the identification of the methicillin (meticillin)-resistant (MRSA) and methicillin-susceptible (MSSA) clonal complexes (CCs) and clones of Staphylococcus aureus circulating in a Spanish hospital recently. Of 81 isolates tested, 32.1% were MRSA. Most of them carried staphylococcal cassette chromosome mec (SCCmec) IVc (88.5%) and belonged to CC5 (88.5%; multilocus sequence typing types ST125 [mainly associated with spa type t067], ST5, and ST228). A higher diversity was found among MSSA isolates (67.9%). Eighty percent shared the genetic background of major MRSA lineages (CC5 [38.2%; ST125 and ST5], CC30 [25.5%; ST30], CC45 [14.5%; ST45 and ST47], and CC8 [1.8%; ST8]), but CC12, CC15, CC51, and CC59 were also detected. Many exotoxin genes were present in each of the 81 isolates, independent of whether they were involved in sepsis (11 to 22) or other types of infections (13 to 21), and they appeared in 73 combinations. The relevant data are that (i) all isolates were positive for hemolysin and leukotoxin genes (98.8% for lukED and 25.9% for lukPV); (ii) all contained an enterotoxin gene cluster (egc with or without seu), frequently with one or more genes encoding classical enterotoxins; (iii) about half were positive for tst and 95% were positive for exfoliatin-encoding genes (eta, etb, and/or etd); and (iv) the four agr groups were detected, with agrII (55.6%) and agrIII (23.5%) being the most frequent. Taken together, results of the present study suggest a frequent acquisition and/or loss of exotoxin genes, which may be mediated by efficient intralineage transfer of mobile genetic elements and exotoxin genes therein and by eventual breakage of interlineage barriers. PMID:19458176

  9. Typing of Panton-Valentine leukocidin-encoding phages carried by methicillin-susceptible and methicillin-resistant Staphylococcus aureus from Italy.

    PubMed

    Sanchini, A; Del Grosso, M; Villa, L; Ammendolia, M G; Superti, F; Monaco, M; Pantosti, A

    2014-11-01

    Panton-Valentine leukocidin (PVL) is the hallmark of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) but can also be found in methicillin-susceptible S. aureus (MSSA) sharing pathogenic and epidemiological characteristics of CA-MRSA. PVL is encoded by two co-transcribed genes that are carried by different staphylococcal bacteriophages. We applied an extended PCR-based typing scheme for the identification of two morphological groups (elongated-head group and icosahedral-head group I phages) and specific PVL phage types in S. aureus isolates recovered in Italy. We examined 48 PVL-positive isolates (25 MSSA and 23 MRSA) collected from different hospital laboratories from April 2005 to May 2011. spa typing, multilocus sequence typing and staphylococcal cassette chromosome mec typing were applied to categorize the isolates. Phage typeability was 48.0% in MSSA and 91.3% in MRSA, highlighting the limitation of the PCR typing scheme when applied to PVL-positive MSSA. Five different PVL phages and two variants of a known phage were detected, the most prevalent being ΦSa2usa, recovered in 15 out of 48 (31.2%) isolates, and carried by both MSSA and MRSA belonging to CC8 and CC5. The recently described ΦTCH60 was recovered in four isolates. A PVL phage (ΦSa119) from an ST772 MRSA, that was not detected using the previous typing scheme, was sequenced, and new primers were designed for the identification of the icosahedral-head group II PVL phages present in ST772 and ST59 MRSA. A comprehensive PVL-phage typing can contribute to the understanding of the epidemiology and evolution of PVL-positive MSSA and MRSA.

  10. Methicillin-resistant Staphylococcus aureus infected gluteal compartment syndrome with rhabdomyolysis in a bodybuilder

    PubMed Central

    Woon, Colin YL; Patel, Kushal R; Goldberg, Benjamin A

    2016-01-01

    Gluteal compartment syndrome (GCS) is a rare condition. We present a case of gluteal muscle strain with hematoma formation, methicillin-resistant Staphylococcus aureus (MRSA) superinfection, leading to acute GCS, rhabdomyolysis and acute kidney injury. This combination of diagnoses has not been reported in the literature. A 36-year-old Caucasian male presented with buttock pain, swelling and fever after lifting weights. Gluteal compartment pressure was markedly elevated compared with the contralateral side. Investigations revealed elevated white blood cell, erythrocyte sedimentation rate, C-reactive protein, creatine kinase, creatinine and lactic acid. Urinalysis was consistent with myoglobinuria. Magnetic resonance imaging showed increased T2 signal in the gluteus maximus and a central hematoma. Cultures taken from the emergency debridement and fasciotomy revealed MRSA. He had repeat, debridement 2 d later, and delayed primary closure 3 d after. GCS is rare and must be suspected when patients present with pain and swelling after an inciting event. They are easily diagnosed with compartment pressure monitoring. The treatment of gluteal abscess and compartment syndrome is the same and involves rapid surgical debridement. PMID:27190761

  11. [Successful treatment of methicillin-resistant staphylococcus aureus meningitis by intrathecal injection of vancomycin].

    PubMed

    Goto, Kazuya; Ohi, Takekazu; Namba, Akiko; Uemura, Norihito; Kitaguchi, Hiroshi

    2011-04-01

    A 70-year-old Japanese man developed fever, headache, and lumbago, presumably due to an epidural abscess caused by methicillin-resistant Staphylococcus aureus (MRSA) in the L5-S2 region. On the night of admission to our hospital, he showed disorientation to places and abnormal eating behavior, indicating a complication of MRSA meningitis. Cerebrospinal fluid (CSF) examination confirmed this diagnosis. Although he was treated with venous infusion of vancomycin and meropenem, the CSF culture remained positive for MRSA even a week after the treatment, and Gram-positive cocci were also seen in the CSF. An intrathecal injection of vancomycin (10mg/day) was subsequently added, which resulted in absence of the organism on Gram-stained CSF smear and CSF culture a week later. His condition improved without any adverse effects. Vancomycin cannot freely penetrate the blood-brain barrier (BBB); therefore, when administered intravenously, its concentration in the CSF is insufficient. Therefore, intrathecal injection of vancomycin is necessary to achieve the desired bacteriocidal level in the CSF. Thus, intrathecal administration of vancomycin seems a very effective and safe treatment for MRSA meningitis.

  12. First description of PVL-positive methicillin-resistant Staphylococcus aureus (MRSA) in wild boar meat.

    PubMed

    Kraushaar, Britta; Fetsch, Alexandra

    2014-09-01

    Staphylococcus aureus is an important food-borne pathogen due to the ability of enterotoxigenic strains to produce staphylococcal enterotoxins (SEs) in food. Methicillin-resistant S. aureus (MRSA) is also an important pathogen for humans, causing severe and hard to treat diseases in hospitals and in the community due to its multiresistance against antimicrobials. In particular, strains harbouring genes encoding for the Panton-Valentine leukocidin (PVL) toxin are of concern from a public health perspective as they are usually capable of causing severe skin and soft tissue infections (sSSTIs) and occasionally necrotizing pneumonia which is associated with high mortality. This is the first report on the detection of MRSA with genes encoding for PVL in wild boar meat. Among the 28 MRSA isolated from wild boar meat in the course of a national monitoring programme in Germany, seven harboured PVL-encoding genes. Six of the isolates were identical according to the results of spa-, MLST-, microarray- and PFGE-typing. They could be assigned to the epidemic MRSA clone USA300. Epidemiological investigations revealed that people handling the food were the most likely common source of contamination with these MRSA. These findings call again for suitable hygienic measures at all processing steps of the food production chain. The results of the study underline that monitoring along the food chain is essential to closely characterise the total burden of MRSA for public health.

  13. USA300 Methicillin-Resistant Staphylococcus aureus, United States, 2000-2013.

    PubMed

    Carrel, Margaret; Perencevich, Eli N; David, Michael Z

    2015-11-01

    In the United States, methicillin-resistant Staphylococcus aureus (MRSA) with the USA300 pulsed-field gel electrophoresis type causes most community-associated MRSA infections and is an increasingly common cause of health care-associated MRSA infections. USA300 probably emerged during the early 1990s. To assess the spatiotemporal diffusion of USA300 MRSA and USA100 MRSA throughout the United States, we systematically reviewed 354 articles for data on 33,543 isolates, of which 8,092 were classified as USA300 and 2,595 as USA100. Using the biomedical literature as a proxy for USA300 prevalence among genotyped MRSA samples, we found that USA300 was isolated during 2000 in several states, including California, Texas, and midwestern states. The geographic mean center of USA300 MRSA then shifted eastward from 2000 to 2013. Analyzing genotyping studies enabled us to track the emergence of a new, successful MRSA type in space and time across the country.

  14. From pig to pork: methicillin-resistant Staphylococcus aureus in the pork production chain.

    PubMed

    Lassok, Birgit; Tenhagen, Bernd-Alois

    2013-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a major global public health concern and could be a food safety issue. Recurrent reports have documented that pig herds are an important reservoir for MRSA, specifically the livestock-associated sequence type 398. The high prevalence of MRSA in pig primary production facilities and the frequent detection of MRSA of the same types in pork and pig meat products raise the question of underlying mechanisms behind the introduction and transmission of MRSA along the pork production chain. A comprehensive review of current literature on the worldwide presence of livestock-associated MRSA in various steps of the pork production chain revealed that the slaughter process plays a decisive role in MRSA transmission from farm to fork. Superficial heat treatments such as scalding and flaming during the slaughter process can significantly reduce the burden of MRSA on the carcasses. However, recontamination with MRSA might occur via surface treating machinery, as a result of fecal contamination at evisceration, or via increased human handling during meat processing. By optimizing processes for carcass decontamination and avoiding recontamination by effective cleaning and personal hygiene management, transmission of MRSA from pig to pork can be minimized.

  15. The Frequency of Methicillin-Resistant Staphylococcus aureus and Coagulase Gene Polymorphism in Egypt

    PubMed Central

    Abdulghany, Hend M.; Khairy, Rasha M.

    2014-01-01

    The current study aimed to use Coagulase gene polymorphism to identify methicillin-resistant Staphylococcus aureus (MRSA) subtypes isolated from nasal carriers in Minia governorate, Egypt, evaluate the efficiency of these methods in discriminating variable strains, and compare these subtypes with antibiotypes. A total of 400 specimens were collected from nasal carriers in Minia governorate, Egypt, between March 2012 and April 2013. Fifty-eight strains (14.5%) were isolated and identified by standard microbiological methods as MRSA. The identified isolates were tested by Coagulase gene RFLP typing. Out of 58 MRSA isolates 15 coa types were classified, and the amplification products showed multiple bands (1, 2, 3, 4, 5, and 8 bands). Coagulase gene PCR-RFLPs exhibited 10 patterns that ranged from 1 to 8 fragments with AluI digestion. Antimicrobial susceptibility testing with a panel of 8 antimicrobial agents showed 6 different antibiotypes. Antibiotype 1 was the most common phenotype with 82.7%. The results have demonstrated that many new variants of the coa gene are present in Minia, Egypt, different from those reported in the previous studies. So surveillance of MRSA should be continued. PMID:26904738

  16. Nasal Methicillin-Resistant S. Aureus is a Major Risk for Mediastinitis in Pediatric Cardiac Surgery

    PubMed Central

    2015-01-01

    Background: Mediastinitis caused by methicillin-resistant Staphylococcus aureus (MRSA) is a serious complication after pediatric cardiac surgery. An outbreak of surgical site infections (SSIs) provided the motivation to implement SSI prevention measures in our institution. Methods: Subjects comprised 174 pediatric patients who underwent open-heart surgery after undergoing preoperative nasal culture screening. The incidence of SSIs and mediastinitis was compared between an early group, who underwent surgery before SSI measures (Group E, n = 73), and a recent group, who underwent surgery after these measures (Group R, n = 101), and factors contributing to the occurrence of mediastinitis were investigated. Results: The incidence of both SSIs and Mediastinitis has significantly decreased after SSI measures. With regard to factors that significantly affected mediastinitis, preoperative factors were “duration of preoperative hospitalization” and “preoperative MRSA colonization,” intraoperative factors were “Aristotle basic complexity score,” “operation time,” “cardiopulmonary bypass circuit volume” and “lowest rectal temperature.” And postoperative factor was “blood transfusion volume.” Patients whose preoperative nasal cultures were MRSA-positive suggested higher risk of MRSA mediastinitis. Conclusions: SSI prevention measures significantly reduced the occurrence of SSIs and mediastinitis. Preoperative MRSA colonization should be a serious risk factor for mediastinitis following pediatric cardiac surgeries. PMID:25641035

  17. Empirical therapy in Methicillin-resistant Staphylococcus Aureus infections: An Up-To-Date approach.

    PubMed

    VanEperen, Alison S; Segreti, John

    2016-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) continues to be an important pathogen worldwide, with high prevalence of infection in both community and hospital settings. Timely and appropriate choice of empirical therapy in the setting of MRSA infection is imperative due to the high rate of associated morbidity and mortality with MRSA infections. Initial choices should be made based on the site and severity of the infection, most notably moderate skin and soft tissue infections which may be treated with oral antibiotics (trimethoprim-sulfamethoxazole, clindamycin, doxycycline/minocycline, linezolid) in the outpatient setting, versus choice of parenteral therapy in the inpatient setting of more invasive or severe disease. Though the current recommendations continue to strongly rely on vancomycin as a standard empiric choice in the setting of severe/invasive infections, alternative therapies exist with studies supporting their non-inferiority. This includes the use of linezolid in pneumonia and severe skin and skin structure infections (SSSI) and daptomycin for MRSA bacteremia, endocarditis, SSSIs and bone/joint infections. Additionally, concerns continue to arise in regards to vancomycin, such as increasing isolate MICs, and relatively high rates of clinical failures with vancomycin. Thus, the growing interest in vanomycin alternatives, such as ceftaroline, ceftobribole, dalbavancin, oritavancin, and tedizolid, and their potential role in treating MRSA infections.

  18. Methicillin-resistant Staphylococcus aureus genotyping using a small set of polymorphisms.

    PubMed

    Stephens, Alex J; Huygens, Flavia; Inman-Bamber, John; Price, Erin P; Nimmo, Graeme R; Schooneveldt, Jacqueline; Munckhof, Wendy; Giffard, Philip M

    2006-01-01

    The aim of this study was to identify a set of genetic polymorphisms that efficiently divides methicillin-resistant Staphylococcus aureus (MRSA) strains into groups consistent with the population structure. The rationale was that such polymorphisms could underpin rapid real-time PCR or low-density array-based methods for monitoring MRSA dissemination in a cost-effective manner. Previously, the authors devised a computerized method for identifying sets of single nucleotide polymorphisms (SNPs) with high resolving power that are defined by multilocus sequence typing (MLST) databases, and also developed a real-time PCR method for interrogating a seven-member SNP set for genotyping S. aureus. Here, it is shown that these seven SNPs efficiently resolve the major MRSA lineages and define 27 genotypes. The SNP-based genotypes are consistent with the MRSA population structure as defined by eBURST analysis. The capacity of binary markers to improve resolution was tested using 107 diverse MRSA isolates of Australian origin that encompass nine SNP-based genotypes. The addition of the virulence-associated genes cna, pvl and bbp/sdrE, and the integrated plasmids pT181, pI258 and pUB110, resolved the nine SNP-based genotypes into 21 combinatorial genotypes. Subtyping of the SCCmec locus revealed new SCCmec types and increased the number of combinatorial genotypes to 24. It was concluded that these polymorphisms provide a facile means of assigning MRSA isolates into well-recognized lineages.

  19. Methicillin-resistant Staphylococcus aureus (MRSA): is there a need to change clinical practice?

    PubMed

    Baird, V L; Hawley, R

    2000-12-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a virulent organism that causes significant mortality and morbidity especially to patients in critical care areas (CCAs). MRSA can (and does in some cases) also contribute to an increased length of hospital stay and higher health care costs. The literature proposes that routine screening of patients in CCAs is an effective strategy to control MRSA. Furthermore, placing patients in contact isolation until screening results are confirmed can prevent the spread of MRSA. The policies for management of MRSA patients and the incidence of MRSA infection vary widely. The preliminary findings from this review suggest that a uniform policy regarding routine screening and infection control management for all CCA patients should be recommended. A uniform policy has the potential to reduce rates of infection, cross-contamination and associated health costs attributed to MRSA management. However, further research is required before changes to infection control policy can be recommended. The outcomes from this review will be used to increase staff awareness of current infection control practices for MRSA patients in critical care areas and encourage further research.

  20. Surveillance of hospital-acquired methicillin-resistant Staphylococcus aureus in South Australia.

    PubMed

    Cooper, Celia; Ochota, Meredith A

    2003-01-01

    In September 2001, the South Australian state-wide methicillin-resistant Staphylococcus aureus (MRSA) surveillance system was expanded to include three surveillance indicators namely: estimated MRSA burden, MRSA morbidity and estimated MRSA acquisition. The last two indicator rates have been stratified into intensive care unit (ICU) versus non-ICU. Between September 2001 and March 2002, state-wide MRSA burden rates (prevalence) ranged from 27.5 to 39.8 per 10,000 occupied bed days (OBDs). Acquisition rates ranged from 28.2 to 69.0 per 10,000 OBDs (ICU) and 6.3 to 10.1 per 10,000 OBDs (non-ICU). Morbidity rates ranged from 12.9 to 43.1 per 10,000 OBDs (ICU) and 3.0 to 5.0 per 10,000 OBDs (non-ICU). In association with the changes to surveillance indicators, a new monthly surveillance report was developed. Assuring confidentiality to individual contributing hospitals has been a major consideration in the development of the data collection system. Individual contributors have access only to their own indicator rates and pooled state-wide indicator rates. Contributing institutions are urged to use great caution if wishing to compare their own rates with state-wide rates. In particular, contributors are asked to take inter-institutional differences in MRSA burden and casemix complexity into account when making such comparisons.

  1. First description of PVL-positive methicillin-resistant Staphylococcus aureus (MRSA) in wild boar meat.

    PubMed

    Kraushaar, Britta; Fetsch, Alexandra

    2014-09-01

    Staphylococcus aureus is an important food-borne pathogen due to the ability of enterotoxigenic strains to produce staphylococcal enterotoxins (SEs) in food. Methicillin-resistant S. aureus (MRSA) is also an important pathogen for humans, causing severe and hard to treat diseases in hospitals and in the community due to its multiresistance against antimicrobials. In particular, strains harbouring genes encoding for the Panton-Valentine leukocidin (PVL) toxin are of concern from a public health perspective as they are usually capable of causing severe skin and soft tissue infections (sSSTIs) and occasionally necrotizing pneumonia which is associated with high mortality. This is the first report on the detection of MRSA with genes encoding for PVL in wild boar meat. Among the 28 MRSA isolated from wild boar meat in the course of a national monitoring programme in Germany, seven harboured PVL-encoding genes. Six of the isolates were identical according to the results of spa-, MLST-, microarray- and PFGE-typing. They could be assigned to the epidemic MRSA clone USA300. Epidemiological investigations revealed that people handling the food were the most likely common source of contamination with these MRSA. These findings call again for suitable hygienic measures at all processing steps of the food production chain. The results of the study underline that monitoring along the food chain is essential to closely characterise the total burden of MRSA for public health. PMID:25016468

  2. Shortened Time to Identify Staphylococcus Species from Blood Cultures and Methicillin Resistance Testing Using CHROMAgar

    PubMed Central

    Chihara, Shingo; Hayden, Mary K.; Minogue-Corbett, Eileen; Singh, Kamaljit

    2009-01-01

    The ability to rapidly differentiate coagulase-negative staphylococcus (CoNS) from Staphylococcus aureus and to determine methicillin resistance is important as it affects the decision to treat empiric antibiotic selection. The objective of this study was to evaluate CHROMagar S. aureus and CHROMagar MRSA (Becton Dickinson) for rapid identification of Staphylococcus spp. directly from blood cultures. Consecutive blood culture bottles (BacT Alert 3D SA and SN, bioMérieux) growing gram-positive cocci in clusters were evaluated. An aliquot was plated onto CHROMagar MRSA (C-MRSA) and CHROMagar S. aureus (C-SA) plates, which were read at 12 to 16 hours. C-SA correctly identified 147/147 S. aureus (100% sensitivity); 2 CoNS were misidentified as S. aureus (98% specificity). C-MRSA correctly identified 74/77 MRSA (96% sensitivity). None of the MSSA isolates grew on C-MRSA (100% specificity). In conclusion, CHROMagar is a rapid and sensitive method to distinguish MRSA, MSSA, and coagulase-negative Staphylococcus and may decrease time of reporting positive results. PMID:20016679

  3. Kinase Inhibitors that Increase the Sensitivity of Methicillin Resistant Staphylococcus aureus to β-Lactam Antibiotics

    PubMed Central

    Vornhagen, Jay; Burnside, Kellie; Whidbey, Christopher; Berry, Jessica; Qin, Xuan; Rajagopal, Lakshmi

    2015-01-01

    Staphylococcus aureus are Gram-positive bacteria that are the leading cause of recurrent infections in humans that include pneumonia, bacteremia, osteomyelitis, arthritis, endocarditis, and toxic shock syndrome. The emergence of methicillin resistant S. aureus strains (MRSA) has imposed a significant concern in sustained measures of treatment against these infections. Recently, MRSA strains deficient in expression of a serine/threonine kinase (Stk1 or PknB) were described to exhibit increased sensitivity to β-lactam antibiotics. In this study, we screened a library consisting of 280 drug-like, low-molecular-weight compounds with the ability to inhibit protein kinases for those that increased the sensitivity of wild-type MRSA to β-lactams and then evaluated their toxicity in mice. We report the identification of four kinase inhibitors, the sulfonamides ST085384, ST085404, ST085405, and ST085399 that increased sensitivity of WT MRSA to sub-lethal concentrations of β-lactams. Furthermore, these inhibitors lacked alerting structures commonly associated with toxic effects, and toxicity was not observed with ST085384 or ST085405 in vivo in a murine model. These results suggest that kinase inhibitors may be useful in therapeutic strategies against MRSA infections. PMID:26506394

  4. Length of stay an important mediator of hospital-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Wong, J G; Chen, M I; Win, M K; Ng, P Y; Chow, A

    2016-04-01

    Hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) is becoming increasingly established in Asian hospitals. The primary aim of this study was to decompose the risk factors for HA-MRSA based on conceptual clinical pathways. The secondary aim was to show the amount of effect attributable to antibiotic exposure and total length of stay before outcome (LBO) so that institutions can manage at-risk patients accordingly. A case-control study consisting of 1200 inpatients was conducted in a large tertiary hospital in Singapore between January and December 2006. Results from the generalized structural equation model (GSEM) show that LBO [adjusted odds ratio (aOR) 14·9, 95% confidence interval (CI) 8·7-25·5], prior hospitalization (aOR 6·2, 95% CI 3·3-11·5), and cumulative antibiotic exposure (aOR 3·5, 95% CI 2·3-5·3), directly affected HA-MRSA acquisition. LBO accounted for the majority of the effects due to age (100%), immunosuppression (67%), and surgery (96%), and to a lesser extent for male gender (22%). Our model enabled us to account and quantify effects of intermediaries. LBO was found to be an important mediator of age, immunosuppression and surgery on MRSA infection. Traditional regression approaches will not only give different conclusions but also underestimate the effects. Hospitals should minimize the hospital stay when possible to reduce the risk of MRSA.

  5. Longitudinal study on the colonisation and transmission of methicillin-resistant Staphylococcus aureus in pig farms.

    PubMed

    Bangerter, Patrick Daniel; Sidler, Xaver; Perreten, Vincent; Overesch, Gudrun

    2016-02-01

    Knowledge about the dynamics of methicillin-resistant Staphylococcus aureus (MRSA) in pigs lacks detail at the level of individual animal. The aim of our study was therefore to determine the colonisation status of MRSA in individual pigs from birth to slaughter in order to gain a better understanding of substantial factors involved in transmission. Two farrow-to-finish and two grow-to-finish herds were included in the study. A total of 1728 nasal swabs from 390 pigs and 592 environmental wipes were collected at 11 different time points. Intermittent colonisation throughout the entire production cycle was conspicuous in the tracking of MRSA in individual pigs. Almost all pigs from a MRSA-positive herd changed MRSA status several times, which implies that pigs are transiently rather than permanently colonised. We highly recommend the definition of MRSA status at herd level rather that at the level of the individual pig when considering prevention measures against MRSA. Therefore, to avoid the further spread of MRSA in countries with moderate prevalence, such as in Switzerland, defining farms as MRSA positive or MRSA negative and allowing the trade of pigs only within herds of the same status seems feasible. This will also be important for combating the further dissemination of livestock-associated (LA)-MRSA into healthcare facilities and the community via humans who have close contact with animals.

  6. Low methicillin-resistant Staphylococcus aureus carriage rate among Italian dental students.

    PubMed

    Petti, Stefano; Kakisina, Naomy; Volgenant, Catherine M C; Messano, Giuseppe A; Barbato, Ersilia; Passariello, Claudio; de Soet, Johannes J

    2015-12-01

    We assessed methicillin-resistant Staphylococcus aureus (MRSA) carriage rate among dental students from an Italian university. A total of 157 subjects participated (67 preclinical students and 90 clinical students); samples were collected from the nose, mouth, and skin. Five preclinical students and 0 clinical students were MRSA-positive. Carriage rates were 3.2% (95% confidence interval [CI], 0.4%-6.0%) overall, 7.5% (95% CI, 1.2%-13.8%) in preclinical students and 0% in clinical students. There were 2 MRSA clusters among the preclinical students: 3 second-year and 2 first-year students, who sat close to one another in the classroom the day of the sample. MRSA carriage was not associated with dental health care. The pooled carriage rate among dental students was assessed to obtain a reliable figure of carriage rate unaffected by local conditions. The 4 published surveys were pooled, and the fixed-effects method was used. Among the 484 dental students, the pooled carriage rate was 4.1% (95% CI, 2.4%-5.8%).

  7. Rapid first-line discrimination of methicillin resistant Staphylococcus aureus strains using MALDI-TOF MS.

    PubMed

    Østergaard, Claus; Hansen, Sanne G K; Møller, Jens K

    2015-12-01

    Fast and reliable discrimination of methicillin-resistant Staphylococcus aureus (MRSA) isolates is essential in identifying an outbreak. Molecular typing methods, such as S. aureus protein A (spa) typing, multi locus sequence typing (MLST) and pulse field gel electrophoresis (PFGE) are generally used for this purpose. These methods are all relatively time-consuming and not performed routinely in all laboratories. The aim of this study is to examine whether MALDI-TOF MS can be used as a fast, simple and easily implemented method for first-line discrimination of MRSA isolates. Mass spectra from 600 clinical MRSA isolates were included in the study, representing 89 spa types, associated with 16 different known clonal complexes. All spectra were obtained directly from colony material obtained from overnight cultures without prior protein extraction. We identified 43 useful discriminatory m/z-values (peaks) and used a concept of arranging these peaks into pairs or small clusters within a small mass range, allowing for quality control of the spectra obtained. Using this concept we could reproducibly characterise and arrange the isolates into 26 MALDI-TOF groups, which strongly correlated with spa types and clonal complexes. The results of this study clearly show that MALDI-TOF MS can be used for first-line discrimination of MRSA isolates, using a simple and fast method that is easy to implement as part of routine testing.

  8. Determination of enterotoxigenic and methicillin resistant Staphylococcus aureus in ice cream.

    PubMed

    Gücükoğlu, Ali; Çadirci, Özgür; Terzi, Göknur; Kevenk, T Onur; Alişarli, Mustafa

    2013-05-01

    The aim of this study was to determine the prevalence of enterotoxigenic and methicillin-resistant Staphylococcus aureus in ice creams. After culture-based identification of isolates, the presence of 16S rRNA and nuc was confirmed by mPCR. S. aureus was identified in 18 of 56 fruity (32.1%), 4 of 32 vanilla (12.5%), and 1 of 12 chocolate (8.3%) ice creams. S. aureus was identified as 38 isolates in 23 ice cream samples by culture-based techniques, but only 35 isolates were confirmed by PCR as S. aureus. To determine the enterotoxigenic properties of PCR-confirmed S. aureus isolates, a toxin detection kit was used (SET RPLA®). Of the 12 enterotoxigenic S. aureus isolates, 9 SEB (75%), 1 SED (8.3%), 1 SEB+SED (8.3%), and 1 SEA+SEB+SED (8.3%) expressing isolates were found. The presence of enterotoxin genes (sea, seb, sed) was identified in 13 (37.1%) out of 35 isolates by the mPCR technique. In the ice cream isolates, the sea, seb, and sed genes were detected: 1 sea (7.6%), 9 seb (69.2%), 1 sed (7.6%), 1 seb+sed (7.6%), and 1 sea+seb+sed (7.6%), respectively. The sec gene was not detected in any of these isolates. One of the 35 (2.8%) S. aureus strain was mecA positive.

  9. The Control of Methicillin-Resistant Staphylococcus aureus Blood Stream Infections in England

    PubMed Central

    Duerden, Brian; Fry, Carole; Johnson, Alan P.; Wilcox, Mark H.

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) blood stream infection (BSI) is a major healthcare burden in some but not all healthcare settings, and it is associated with 10%–20% mortality. The introduction of mandatory reporting in England of MRSA BSI in 2001 was followed in 2004 by the setting of target reductions for all National Health Service hospitals. The original national target of a 50% reduction in MRSA BSI was considered by many experts to be unattainable, and yet this goal has been far exceeded (∼80% reduction with rates still declining). The transformation from endemic to sporadic MRSA BSI involved the implementation of serial national infection prevention directives, and the deployment of expert improvement teams in organizations failed to meet their improvement trajectory targets. We describe and appraise the components of the major public health infection prevention campaign that yielded major reductions in MRSA infection. There are important lessons and opportunities for other healthcare systems where MRSA infection remains endemic. PMID:26380336

  10. Treatment outcomes for serious infections caused by methicillin-resistant Staphylococcus aureus with reduced vancomycin susceptibility.

    PubMed

    Howden, Benjamin P; Ward, Peter B; Charles, Patrick G P; Korman, Tony M; Fuller, Andrew; du Cros, Philipp; Grabsch, Elizabeth A; Roberts, Sally A; Robson, Jenny; Read, Kerry; Bak, Narin; Hurley, James; Johnson, Paul D R; Morris, Arthur J; Mayall, Barrie C; Grayson, M Lindsay

    2004-02-15

    Although infections caused by methicillin-resistant Staphylococcus aureus with reduced vancomycin susceptibility (SA-RVS) have been reported from a number of countries, including Australia, the optimal therapy is unknown. We reviewed the clinical features, therapy, and outcome of 25 patients with serious infections due to SA-RVS in Australia and New Zealand. Eight patients had endocarditis, 9 had bacteremia associated with deep-seated infection, 6 had osteomyelitis or septic arthritis, and 2 had empyema. All patients had received vancomycin before the isolation of SA-RVS, and glycopeptide treatment had failed for 19 patients (76%). Twenty-one patients subsequently received active treatment, which was effective for 16 patients (76%). Eighteen patients received linezolid, which was effective in 14 (78%), including 4 patients with endocarditis. Twelve patients received a combination of rifampicin and fusidic acid. Surgical intervention was required for 15 patients (60%). Antibiotic therapy, especially linezolid with or without rifampicin and fusidic acid, in conjunction with surgical debulking is effective therapy for the majority of patients with serious infections (including endocarditis) caused by SA-RVS.

  11. Methicillin-resistant Staphylococcus aureus sequence type 239-III, Ohio, USA, 2007-2009.

    PubMed

    Wang, Shu-Hua; Khan, Yosef; Hines, Lisa; Mediavilla, José R; Zhang, Liangfen; Chen, Liang; Hoet, Armando; Bannerman, Tammy; Pancholi, Preeti; Robinson, D Ashley; Kreiswirth, Barry N; Stevenson, Kurt B

    2012-10-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a human pathogen that has diverse molecular heterogeneity. Most MRSA strains in the United States are pulsed-field gel electrophoresis USA100 sequence type (ST) 5 and USA300 ST8. Infections with MRSA ST239-III are common and found during health care-associated outbreaks. However, this strain has been rarely reported in the United States. As part of a study supported by the Prevention Epicenter Program of the Centers for Disease Control and Prevention (Atlanta, GA, USA), which evaluated transmission of MRSA among hospitals in Ohio, molecular typing identified 78 (6%) of 1,286 patients with MRSA ST239-III infections. Ninety-five percent (74/78) of these infections were health care associated, and 65% (51/78) of patients had histories of invasive device use. The crude case-fatality rate was 22% (17/78). Identification of these strains, which belong to a virulent clonal group, emphasizes the need for molecular surveillance. PMID:23018025

  12. Melittin, a honeybee venom-derived antimicrobial peptide, may target methicillin-resistant Staphylococcus aureus

    PubMed Central

    CHOI, JI HAE; JANG, A YEUNG; LIN, SHUNMEI; LIM, SANGYONG; KIM, DONGHO; PARK, KYUNGHO; HAN, SANG-MI; YEO, JOO-HONG; SEO, HO SEONG

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is difficult to treat using available antibiotic agents. Honeybee venom has been widely used as an oriental treatment for several inflammatory diseases and bacterial infections. The venom contains predominantly biologically active compounds, however, the therapeutic effects of such materials when used to treat MRSA infections have not been investigated extensively. The present study evaluated bee venom and its principal active component, melittin, in terms of their antibacterial activities and in vivo protection against MRSA infections. In vitro, bee venom and melittin exhibited comparable levels of antibacterial activity, which was more marked against MRSA strains, compared with other Gram-positive bacteria. When MRSA-infected mice were treated with bee venom or melittin, only the latter animals were successfully rescued from MRSA- induced bacteraemia or exhibited recovery from MRSA-infected skin wounds. Together, the data of the present study demonstrated for the first time, to the best of our knowledge, that melittin may be used as a promising antimicrobial agent to enhance the healing of MRSA-induced wounds. PMID:26330195

  13. Methicillin-resistant Staphylococcus aureus sequence type 239-III, Ohio, USA, 2007-2009.

    PubMed

    Wang, Shu-Hua; Khan, Yosef; Hines, Lisa; Mediavilla, José R; Zhang, Liangfen; Chen, Liang; Hoet, Armando; Bannerman, Tammy; Pancholi, Preeti; Robinson, D Ashley; Kreiswirth, Barry N; Stevenson, Kurt B

    2012-10-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a human pathogen that has diverse molecular heterogeneity. Most MRSA strains in the United States are pulsed-field gel electrophoresis USA100 sequence type (ST) 5 and USA300 ST8. Infections with MRSA ST239-III are common and found during health care-associated outbreaks. However, this strain has been rarely reported in the United States. As part of a study supported by the Prevention Epicenter Program of the Centers for Disease Control and Prevention (Atlanta, GA, USA), which evaluated transmission of MRSA among hospitals in Ohio, molecular typing identified 78 (6%) of 1,286 patients with MRSA ST239-III infections. Ninety-five percent (74/78) of these infections were health care associated, and 65% (51/78) of patients had histories of invasive device use. The crude case-fatality rate was 22% (17/78). Identification of these strains, which belong to a virulent clonal group, emphasizes the need for molecular surveillance.

  14. Atomic force microscopy study of the antibacterial effect of fosfomycin on methicillin-resistant Staphylococcus pseudintermedius

    NASA Astrophysics Data System (ADS)

    Neethirajan, Suresh; DiCicco, Matthew

    2014-08-01

    The influence of fosfomycin on methicillin-resistant Staphylococcus pseudintermedius (MRSP) as the target cell was studied by atomic force microscopy (AFM). Nanoscale images of the effects of the antibiotic fosfomycin on this gram-positive bacterium's cell were obtained in situ without fixing agents. Our study has demonstrated substantial morphological and topographical differences between the control and fosfomycin-treated MRSP cells. The AFM investigations further revealed the rough surface morphology and a 30 % shrinkage in size of the fosfomycin-treated cell and the leakage of cytoplasmic components from the cell. The damage of cell membrane integrity and the cell surface degradation as observed elaborates the antibacterial activity of fosfomycin. The AFM image analysis also reveals that the fosfomycin inhibits cell division, and prevents the adhesion on the surface discouraging the biofilm attachment. The micro-titre plate assay results conform to the atomic force microscopy image analysis. This is the first visual demonstration of the effect of fosfomycin on MRSP cells.

  15. Antimicrobial chemotherapy of septicemia due to methicillin-resistant Staphylococcus aureus.

    PubMed Central

    Cafferkey, M T; Hone, R; Keane, C T

    1985-01-01

    The outcome of treatment of 48 episodes of septicemia due to methicillin-resistant Staphylococcus aureus (MRSA) in 44 patients was assessed. Twenty-six of the patients died; nineteen of them died of infection, and infection was a major contributing factor to the deaths of the remaining seven patients. Fourteen of fifteen patients treated with inadequate antibiotic therapy died, and the other patient developed a mycotic aneurysm of the femoral artery, for which amputation was necessary. Eight of eleven patients treated with amikacin (alone or combined with another antimicrobial) died, and three recovered slowly; only one recovered fully without sequelae. In an additional two patients who failed to respond to amikacin, treatment was changed to vancomycin. Vancomycin was used to treat 18 episodes of MRSA septicemia in 17 patients. In 14 of these episodes the patients recovered fully. One patient died of uncontrolled infection, and in three, infection was a contributing factor but not the major cause of death. Vancomycin was confirmed as antibiotic of choice in treating MRSA septicemia. PMID:3878691

  16. Characterization of methicillin-resistant coagulase-negative staphylococci (MRCoNS) in retail meat.

    PubMed

    Bhargava, Kanika; Zhang, Yifan

    2014-09-01

    This study was to understand the extent of methicillin-resistant coagulase-negative staphylococci (MRCoNS) serving as a mecA reservoir in retail meat. MRCoNS were isolated from retail meat (beef, chicken, and turkey) in Detroit and characterized by sodA gene sequencing for species identification, staphylococcal cassette chromosome mec (SCCmec) typing, and pulsed-field gel electrophoresis (PFGE). Unique MRCoNS isolates recovered from 25 meat samples were comprised of Staphylococcus sciuri (n = 13), Staphylococcus fleuretti (n = 4), Staphylococcus lentus (n = 3), Staphylococcus epidermidis (n = 2), Staphylococcus vitulinus (n = 1), Staphylococcus saprophyticus (n = 1) and Staphylococcus pasteuri (n = 1). Heterogeneous and composite SCCmec types, including I, III, IV, V, I + V and III + V were identified in 16 isolates. Same SCCmec types were recovered in different staphylococcal species and meat sources. Indistinguishable PFGE patterns were also observed in S. sciuri isolated from beef, chicken, and turkey, and with different SCCmec types. In conclusion, multiple CoNS species can serve as reservoirs for mecA. In addition to the clonal transmission of MRCoNS in meat, horizontal occurrence of SCCmec is observed in staphylococcal species.

  17. Community-Associated Methicillin-Resistant Staphylococcus aureus: Epidemiology and Clinical Consequences of an Emerging Epidemic

    PubMed Central

    David, Michael Z.; Daum, Robert S.

    2010-01-01

    Summary: Staphylococcus aureus is an important cause of skin and soft-tissue infections (SSTIs), endovascular infections, pneumonia, septic arthritis, endocarditis, osteomyelitis, foreign-body infections, and sepsis. Methicillin-resistant S. aureus (MRSA) isolates were once confined largely to hospitals, other health care environments, and patients frequenting these facilities. Since the mid-1990s, however, there has been an explosion in the number of MRSA infections reported in populations lacking risk factors for exposure to the health care system. This increase in the incidence of MRSA infection has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). CA-MRSA strains differ from the older, health care-associated MRSA strains; they infect a different group of patients, they cause different clinical syndromes, they differ in antimicrobial susceptibility patterns, they spread rapidly among healthy people in the community, and they frequently cause infections in health care environments as well. This review details what is known about the epidemiology of CA-MRSA strains and the clinical spectrum of infectious syndromes associated with them that ranges from a commensal state to severe, overwhelming infection. It also addresses the therapy of these infections and strategies for their prevention. PMID:20610826

  18. Anti-methicillin-resistant Staphylococcus aureus (MRSA) substance from the marine bacterium Pseudomonas sp. UJ-6.

    PubMed

    Lee, Dae-Sung; Eom, Sung-Hwan; Jeong, Seong-Yun; Shin, Hee Jae; Je, Jae-Young; Lee, Eun-Woo; Chung, Yong-Hyun; Kim, Young-Mog; Kang, Chang-Keun; Lee, Myung-Suk

    2013-03-01

    A multivalent approach to discover a novel antibiotic substance against methicillin-resistant Staphylococcus aureus (MRSA), a marine bacterium, UJ-6, exhibiting an antibacterial activity against MRSA was isolated from seawater. The isolated strain was identified to be Pseudomonas sp. by the morphology, biochemical, and genetical analyses. The ethyl acetate extract of Pseudomonas sp. UJ-6 culture showed significant ant-MRSA activity. Bioassay-guided isolation of the extract using a growth inhibitory assay led to the isolation and identification of an active compound exhibiting anti-MRSA activity. Based on the analyses of the physicochemical and spectroscopic data including nuclear magnetic resonance and mass, the compound was identified to be 1-acetyl-beta-carboline. The minimum inhibitory concentration (MIC) of the compound was determined to be in a range of 32-128 μg/ml against MRSA strains. The MIC values against MRSA were superior or equal to those of other natural compounds such as catechins, suggesting that 1-acetyl-beta-carboline would be a good candidate in applications of the treatment of MRSA infection.

  19. Kinase Inhibitors that Increase the Sensitivity of Methicillin Resistant Staphylococcus aureus to β-Lactam Antibiotics.

    PubMed

    Vornhagen, Jay; Burnside, Kellie; Whidbey, Christopher; Berry, Jessica; Qin, Xuan; Rajagopal, Lakshmi

    2015-01-01

    Staphylococcus aureus are Gram-positive bacteria that are the leading cause of recurrent infections in humans that include pneumonia, bacteremia, osteomyelitis, arthritis, endocarditis, and toxic shock syndrome. The emergence of methicillin resistant S. aureus strains (MRSA) has imposed a significant concern in sustained measures of treatment against these infections. Recently, MRSA strains deficient in expression of a serine/threonine kinase (Stk1 or PknB) were described to exhibit increased sensitivity to β-lactam antibiotics. In this study, we screened a library consisting of 280 drug-like, low-molecular-weight compounds with the ability to inhibit protein kinases for those that increased the sensitivity of wild-type MRSA to β-lactams and then evaluated their toxicity in mice. We report the identification of four kinase inhibitors, the sulfonamides ST085384, ST085404, ST085405, and ST085399 that increased sensitivity of WT MRSA to sub-lethal concentrations of β-lactams. Furthermore, these inhibitors lacked alerting structures commonly associated with toxic effects, and toxicity was not observed with ST085384 or ST085405 in vivo in a murine model. These results suggest that kinase inhibitors may be useful in therapeutic strategies against MRSA infections. PMID:26506394

  20. USA300 Methicillin-Resistant Staphylococcus aureus, United States, 2000–2013

    PubMed Central

    Perencevich, Eli N.; David, Michael Z.

    2015-01-01

    In the United States, methicillin-resistant Staphylococcus aureus (MRSA) with the USA300 pulsed-field gel electrophoresis type causes most community-associated MRSA infections and is an increasingly common cause of health care–associated MRSA infections. USA300 probably emerged during the early 1990s. To assess the spatiotemporal diffusion of USA300 MRSA and USA100 MRSA throughout the United States, we systematically reviewed 354 articles for data on 33,543 isolates, of which 8,092 were classified as USA300 and 2,595 as USA100. Using the biomedical literature as a proxy for USA300 prevalence among genotyped MRSA samples, we found that USA300 was isolated during 2000 in several states, including California, Texas, and midwestern states. The geographic mean center of USA300 MRSA then shifted eastward from 2000 to 2013. Analyzing genotyping studies enabled us to track the emergence of a new, successful MRSA type in space and time across the country. PMID:26484389

  1. In vitro evaluation of DispersinB on methicillin-resistant Staphylococcus pseudintermedius biofilm.

    PubMed

    Turk, Ryen; Singh, Ameet; Rousseau, Joyce; Weese, J Scott

    2013-10-25

    Methicillin resistant Staphylococcus pseudintermedius (MRSP) is an important canine pathogen that has been shown to produce biofilm in vitro. Biofilm production may be an important virulence factor and methods to eliminate biofilm-associated infections are required. An enzyme of Aggregatibacter actinomycetemcomitans, DispersinB, has been shown to degrade the extracellular matrix in the biofilm of a variety of bacteria including Staphylococcus aureus and Staphylococcus epidermidis. The objective of this study was to determine the effect of DispersinB on MRSP biofilm production and eradication in vitro. A quantitative microtitre plate assay was used to assess the impact of DispersinB on 30 MRSP isolates from dogs. While DispersinB did not have any effect on MRSP growth (P=0.98), it reduced biofilm formation (P=0.0002) and degraded established biofilm (P=0.0001). These data indicate that in vivo study of the effect of this enzyme in indicated to determine if it may be a useful treatment option for MRSP biofilm-associated infections.

  2. The economic burden of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA).

    PubMed

    Lee, B Y; Singh, A; David, M Z; Bartsch, S M; Slayton, R B; Huang, S S; Zimmer, S M; Potter, M A; Macal, C M; Lauderdale, D S; Miller, L G; Daum, R S

    2013-06-01

    The economic impact of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) remains unclear. We developed an economic simulation model to quantify the costs associated with CA-MRSA infection from the societal and third-party payer perspectives. A single CA-MRSA case costs third-party payers $2277-$3200 and society $7070-$20 489, depending on patient age. In the United States (US), CA-MRSA imposes an annual burden of $478 million to 2.2 billion on third-party payers and $1.4-13.8 billion on society, depending on the CA-MRSA definitions and incidences. The US jail system and Army may be experiencing annual total costs of $7-11 million ($6-10 million direct medical costs) and $15-36 million ($14-32 million direct costs), respectively. Hospitalization rates and mortality are important cost drivers. CA-MRSA confers a substantial economic burden on third-party payers and society, with CA-MRSA-attributable productivity losses being major contributors to the total societal economic burden. Although decreasing transmission and infection incidence would decrease costs, even if transmission were to continue at present levels, early identification and appropriate treatment of CA-MRSA infections before they progress could save considerable costs.

  3. Fulminant necrotising fasciitis by community-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Non, Lemuel; Kosmin, Aaron

    2015-03-30

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a rare cause of necrotising fasciitis (NF), and is usually not fulminant as in group A Streptococcus (GAS), the archetypal aetiology. We report an unusually fulminant case of NF by CA-MRSA in an immunocompetent patient. A 52-year-old man presented to the emergency department with 1 week of progressive left thigh pain and swelling. The patient had ecchymoses, bullae and hypoesthesia of the involved skin, and CT scan revealed extensive fascial oedema. He was immediately started on broad spectrum antibiotics. Within 12 h of presentation, he underwent surgical debridement. Despite aggressive supportive care, the patient died less than 24 h after presentation. MRSA, with an antibiogram suggestive of a community-acquired strain, was recovered from intraoperative specimens and admission blood cultures. This case underscores that CA-MRSA, while rarely reported, can cause a fulminant presentation of NF similar to GAS in immunocompetent patients.

  4. Methicillin-resistant Staphylococcus aureus in Canada: a historical perspective and lessons learned.

    PubMed

    Cimolai, Nevio

    2010-02-01

    The history of methicillin-resistant Staphylococcus aureus (MRSA) in Canada has many similarities to MRSA evolution worldwide, but especially to that in the United States and United Kingdom. Reports of MRSA occurred as early as 1964, and community isolates were cited in the 1970s. Nosocomial outbreaks were becoming common by 1978 and flourished gradually thereafter. Endemic institutional MRSA became predominant in the 1990s, threatening large teaching hospitals in particular. In the last decade, both hospital-acquired and community-acquired MRSA have created major medical problems in Canada. More recently, an epidemic of Canadian community-acquired MRSA-10, has led to heightened public health concerns. Canadian contributions to MRSA science are numerous, with organized surveillance continuing to mature across the nation. A typing system for epidemic clones is now available and is being judiciously applied. Estimated costs for MRSA surveillance, treatment, and control are extraordinary, paralleling the dramatic rise in the number of MRSA isolations. Whereas surveillance continues to form an essential aspect of MRSA management, control, eradication, and overall diminution, MRSA reservoirs deserve much greater attention. Such efforts, however, must be as widely publicized in the community and in patient homes as they are in medical institutions responsible for both acute and long-term care.

  5. Devastating renal outcome caused by skin infection with methicillin-resistant Staphylococcus aureus

    PubMed Central

    Liang, Jun-Hua; Fang, Yu-Wei; Yang, An-Hung; Tsai, Ming Hsien

    2016-01-01

    Abstract Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging pathogen that infects the skin and soft tissue. However, there are few reports of renal complications from MRSA involving immunoglobulin (Ig)A-dominated rapidly progressive glomerulonephritis (GN). Favorable renal outcomes from IgA GN are achieved by administering timely therapy. In the present study, we describe the case of a healthy young woman suffering from a cutaneous MRSA infection that initially presented with gross hematuria. Six months after eradicating the infection, severe impairment of renal function was noted because of intractable nausea and vomiting. Renal pathology revealed advanced IgA nephropathy with fibrocellular crescent formation. An aggressive treatment plan using immunosuppressants was not adopted because of her irreversible renal pathology, and she was therefore administered maintenance hemodialysis. This instructive case stresses the importance of being aware of the signs of IgA nephropathy post-MRSA infection, such as cutaneous lesions that are mostly painless and accompanied by hematuria and mild proteinuria. If the kidney cannot be salvaged, it will undergo irreversible damage with devastating consequences. PMID:27368023

  6. Characterization of methicillin-resistant coagulase-negative staphylococci (MRCoNS) in retail meat.

    PubMed

    Bhargava, Kanika; Zhang, Yifan

    2014-09-01

    This study was to understand the extent of methicillin-resistant coagulase-negative staphylococci (MRCoNS) serving as a mecA reservoir in retail meat. MRCoNS were isolated from retail meat (beef, chicken, and turkey) in Detroit and characterized by sodA gene sequencing for species identification, staphylococcal cassette chromosome mec (SCCmec) typing, and pulsed-field gel electrophoresis (PFGE). Unique MRCoNS isolates recovered from 25 meat samples were comprised of Staphylococcus sciuri (n = 13), Staphylococcus fleuretti (n = 4), Staphylococcus lentus (n = 3), Staphylococcus epidermidis (n = 2), Staphylococcus vitulinus (n = 1), Staphylococcus saprophyticus (n = 1) and Staphylococcus pasteuri (n = 1). Heterogeneous and composite SCCmec types, including I, III, IV, V, I + V and III + V were identified in 16 isolates. Same SCCmec types were recovered in different staphylococcal species and meat sources. Indistinguishable PFGE patterns were also observed in S. sciuri isolated from beef, chicken, and turkey, and with different SCCmec types. In conclusion, multiple CoNS species can serve as reservoirs for mecA. In addition to the clonal transmission of MRCoNS in meat, horizontal occurrence of SCCmec is observed in staphylococcal species. PMID:24929717

  7. Community-Acquired Methicillin-Resistant Pyogenic Liver Abscess: A Case Report.

    PubMed

    Cherian, Joel; Singh, Rahul; Varma, Muralidhar; Vidyasagar, Sudha; Mukhopadhyay, Chiranjay

    2016-01-01

    Pyogenic liver abscesses are rare with an incidence of 0.5% to 0.8% and are mostly due to hepatobiliary causes (40% to 60%). Most are polymicrobial with less than 10% being caused by Staphylococcus aureus. Of these, few are caused by methicillin-resistant Staphylococcus aureus (MRSA) and fewer still by a community-acquired strain. Here we present a case study of a patient with a community-acquired MRSA liver abscess. The patient presented with fever since 1 month and tender hepatomegaly. Blood tests revealed elevated levels of alkaline phosphatase, C-reactive protein, erythrocyte sedimentation rate, and neutrophilic leukocytosis. Blood cultures were sterile. Ultrasound of the abdomen showed multiple abscesses, from which pus was drained and MRSA isolated. Computed tomography of the abdomen did not show any source of infection, and an amebic serology was negative. The patient was started on vancomycin for 2 weeks, following which he became afebrile and was discharged on oral linezolid for 4 more weeks. Normally a liver abscess is treated empirically with ceftriaxone for pyogenic liver abscess and metronidazole for amebic liver abscess. However, if the patient has risk factors for a Staphylococcal infection, it is imperative that antibiotics covering gram-positive organisms be added while waiting for culture reports. PMID:27540556

  8. In vitro evaluation of BO-3482, a novel dithiocarbamate carbapenem with activity against methicillin-resistant staphylococci.

    PubMed Central

    Adachi, Y; Nakamura, K; Kato, Y; Hazumi, N; Hashizume, T; Nakagawa, S

    1997-01-01

    BO-3482, a dithiocarbamate carbapenem, inhibited clinical isolates of methicillin-resistant staphylococci (MRS) at 6.25 microg/ml (MIC at which 90% of isolates tested are inhibited [MIC90]), while the MIC90 of imipenem was > 100 microg/ml. BO-3482 was generally less active than imipenem against methicillin-susceptible Staphylococcus aureus, streptococci, enterococci, and gram-negative bacteria, although BO-3482 showed better activity (MIC90) than imipenem against Enterococcus faecium, Haemophilus influenzae, Proteus mirabilis, and Clostridium difficile. The affinities (50% inhibitory concentrations) of BO-3482 for penicillin-binding protein (PBP) PBP 2' of MRS and PBP 5 of E. faecium (both PBPs have low affinities for ordinary beta-lactam antibiotics) were 3.8 and 20 microg/ml, respectively, reflecting the greater activity of BO-3482 against MRS than against E. faecium. PMID:9333063

  9. Emergence of cfr-Mediated Linezolid Resistance in a Methicillin-Resistant Staphylococcus aureus Epidemic Clone Isolated from Patients with Cystic Fibrosis

    PubMed Central

    de Dios Caballero, Juan; Pastor, María Dolores; Vindel, Ana; Máiz, Luis; Yagüe, Genoveva; Salvador, Carme; Cobo, Marta; Morosini, María-Isabel; Cantón, Rafael

    2015-01-01

    Resistance to linezolid (LZD) in methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients with cystic fibrosis (CF) is due mainly to ribosomal mutations. We report on four CF patients with LZD-resistant MRSA bronchopulmonary infections by strains carrying the cfr gene. Strains from one patient also harbored the G2576U mutation (23S rRNA) and the G139R substitution (L3 protein). All strains belonged to the epidemic clone ST125 MRSA IVc. Our results support the monitoring of LZD resistance emergence in CF and non-CF MRSA isolates. PMID:26666940

  10. Emergence of cfr-Mediated Linezolid Resistance in a Methicillin-Resistant Staphylococcus aureus Epidemic Clone Isolated from Patients with Cystic Fibrosis.

    PubMed

    de Dios Caballero, Juan; Pastor, María Dolores; Vindel, Ana; Máiz, Luis; Yagüe, Genoveva; Salvador, Carme; Cobo, Marta; Morosini, María-Isabel; del Campo, Rosa; Cantón, Rafael

    2016-03-01

    Resistance to linezolid (LZD) in methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients with cystic fibrosis (CF) is due mainly to ribosomal mutations. We report on four CF patients with LZD-resistant MRSA bronchopulmonary infections by strains carrying the cfr gene. Strains from one patient also harbored the G2576U mutation (23S rRNA) and the G139R substitution (L3 protein). All strains belonged to the epidemic clone ST125 MRSA IVc. Our results support the monitoring of LZD resistance emergence in CF and non-CF MRSA isolates. PMID:26666940

  11. Emergence of cfr-Mediated Linezolid Resistance in a Methicillin-Resistant Staphylococcus aureus Epidemic Clone Isolated from Patients with Cystic Fibrosis.

    PubMed

    de Dios Caballero, Juan; Pastor, María Dolores; Vindel, Ana; Máiz, Luis; Yagüe, Genoveva; Salvador, Carme; Cobo, Marta; Morosini, María-Isabel; del Campo, Rosa; Cantón, Rafael

    2015-12-14

    Resistance to linezolid (LZD) in methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients with cystic fibrosis (CF) is due mainly to ribosomal mutations. We report on four CF patients with LZD-resistant MRSA bronchopulmonary infections by strains carrying the cfr gene. Strains from one patient also harbored the G2576U mutation (23S rRNA) and the G139R substitution (L3 protein). All strains belonged to the epidemic clone ST125 MRSA IVc. Our results support the monitoring of LZD resistance emergence in CF and non-CF MRSA isolates.

  12. Short communication: Prevalence of methicillin resistance in coagulase-negative staphylococci and Staphylococcus aureus isolated from bulk milk on organic and conventional dairy farms in the United States.

    PubMed

    Cicconi-Hogan, K M; Belomestnykh, N; Gamroth, M; Ruegg, P L; Tikofsky, L; Schukken, Y H

    2014-05-01

    The objective of this study was to evaluate the presence of methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus spp. in bulk tank milk samples from 288 organic and conventional dairy farms located in New York, Wisconsin, and Oregon from March 2009 to May 2011. Due to recent publications reporting the presence mecC (a mecA homolog not detected by traditional mecA-based PCR methods), a combination of genotypic and phenotypic approaches was used to enhance the recovery of methicillin-resistant organisms from bulk tank milk. In total, 13 isolates were identified as methicillin resistant: Staph. aureus (n=1), Staphylococcus sciuri (n=5), Staphylococcus chromogenes (n=2), Staphylococcus saprophyticus (n=3), Staphylococcus agnetis (n=1), and Macrococcus caseolyticus (n=1). The single methicillin-resistant Staph. aureus isolate was identified from an organic farm in New York, for an observed 0.3% prevalence at the farm level. The methicillin-resistant coagulase-negative staphylococci prevalence was 2% in the organic population and 5% in the conventional population. We did not identify mecC in any of the isolates from our population. Of interest was the relatively high number of methicillin-resistant Staph. sciuri recovered, as the number of isolates from our study was considerably higher than those recovered from other recent studies that also assessed milk samples. Our research suggests that the presence of a potential methicillin-resistant Staphylococcus reservoir in milk, and likely the dairy farm population in the United States, is independent of the organic or conventional production system.

  13. Short communication: Prevalence of methicillin resistance in coagulase-negative staphylococci and Staphylococcus aureus isolated from bulk milk on organic and conventional dairy farms in the United States.

    PubMed

    Cicconi-Hogan, K M; Belomestnykh, N; Gamroth, M; Ruegg, P L; Tikofsky, L; Schukken, Y H

    2014-05-01

    The objective of this study was to evaluate the presence of methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus spp. in bulk tank milk samples from 288 organic and conventional dairy farms located in New York, Wisconsin, and Oregon from March 2009 to May 2011. Due to recent publications reporting the presence mecC (a mecA homolog not detected by traditional mecA-based PCR methods), a combination of genotypic and phenotypic approaches was used to enhance the recovery of methicillin-resistant organisms from bulk tank milk. In total, 13 isolates were identified as methicillin resistant: Staph. aureus (n=1), Staphylococcus sciuri (n=5), Staphylococcus chromogenes (n=2), Staphylococcus saprophyticus (n=3), Staphylococcus agnetis (n=1), and Macrococcus caseolyticus (n=1). The single methicillin-resistant Staph. aureus isolate was identified from an organic farm in New York, for an observed 0.3% prevalence at the farm level. The methicillin-resistant coagulase-negative staphylococci prevalence was 2% in the organic population and 5% in the conventional population. We did not identify mecC in any of the isolates from our population. Of interest was the relatively high number of methicillin-resistant Staph. sciuri recovered, as the number of isolates from our study was considerably higher than those recovered from other recent studies that also assessed milk samples. Our research suggests that the presence of a potential methicillin-resistant Staphylococcus reservoir in milk, and likely the dairy farm population in the United States, is independent of the organic or conventional production system. PMID:24582450

  14. Alcohol handrubbing and chlorhexidine handwashing are equally effective in removing methicillin-resistant Staphylococcus aureus from health care workers' hands: A randomized controlled trial.

    PubMed

    Ho, Hanley J; Poh, Bee-Fong; Choudhury, Saugata; Krishnan, Prabha; Ang, Brenda; Chow, Angela

    2015-11-01

    We conducted a randomized controlled trial in a tertiary-care hospital in a real-time setting to evaluate the effectiveness of 3 hand hygiene protocols in reducing hand carriage of methicillin-resistant and methicillin-sensitive Staphylococcus aureus among health care workers. Our study shows that use of alcohol handrub, either covering all hand surfaces in no particular order or using the 7-step technique, and chlorhexidine handwashing were equally effective in removing hand carriage of these pathogens. PMID:26190381

  15. Methicillin Resistant Staphylococcus aureus Carriage, Antibiotic Resistance and Molecular Pathogenicity among Healthy Individuals Exposed and Not Exposed to Hospital Environment

    PubMed Central

    Krishnamurthy, Veena; Renushri, Bhadravati Virupaksha; Nagaraj, Elkal Rajappa

    2014-01-01

    Background: Healthcare workers as well as healthy community-dwelling individuals may be colonised by methicillin-resistant Staphylococcus aureus (MRSA). Healthcare workers who carry MRSA may transmit it to patients, causing various nosocomial infections. Literature shows that the differences between MRSA isolated from healthcare settings and from community settings, with regard to multi-drug resistance (traditionally exhibited by the former) and possession of pvl genes (traditionally exhibited by the latter), is diminishing due to a large community reservoir and increasing influx of community harboured strains into the hospital. However, there is no literature on the current scenario in India. Aims and Objectives: This study examines the influence of exposure to hospital environment on MRSA carriage, antimicrobial resistance patterns of MRSA, and the presence of genes encoding five extracellular pathogenicity determinants (pvl, sea, seb, tsst-1 and hly a). Materials and Methods: Nasal, throat and palmar swabs were collected from 119 nursing students of the age group 18-23 years (exposed group) and 100 age matched pharmacy students (non-exposed group). S. aureus was identified and antibiogram obtained as per Clinical and Laboratory Standards Institute (CLSI) guidelines. MRSA was detected by cefoxitin disc diffusion test and by growth on oxacillin screen agar as per CLSI guidelines. Conventional PCR was performed for mecA, pvl, sea, seb, tsst-1 and hly a. Results: The differences in carrier rates, antibiotic resistance patterns and expression of extracellular pathogenicity determinants between MRSA isolates from the two study groups were not significant, and pvl was found in all the MRSA isolates. Conclusion: The nursing students carried MRSA strains similar to those carried by the non-exposed group. Our results suggest that healthcare workers could act as a link and transmit MRSA acquired from the community to patients. PMID:25177563

  16. Effects of Subinhibitory Concentrations of Ceftaroline on Methicillin-Resistant Staphylococcus aureus (MRSA) Biofilms.

    PubMed

    Lázaro-Díez, María; Remuzgo-Martínez, Sara; Rodríguez-Mirones, Cristina; Acosta, Felix; Icardo, Jose M; Martínez-Martínez, Luis; Ramos-Vivas, José

    2016-01-01

    Ceftaroline (CPT) is a novel cephalosporin with in vitro activity against Staphylococcus aureus. Ceftaroline exhibits a level of binding affinity for PBPs in S. aureus including PBP2a of methicillin-resistant S. aureus (MRSA). The aims of this study were to investigate the morphological, physiological and molecular responses of MRSA clinical strains and MRSA biofilms to sub-MICs (1/4 and 1/16 MIC) of ceftaroline by using transmission, scanning and confocal microscopy. We have also used quantitative Real-Time PCR to study the effect of sub-MICs of ceftaroline on the expression of the staphylococcal icaA, agrA, sarA and sasF genes in MRSA biofilms. In one set of experiments, ceftaroline was able to inhibit biofilm formation in all strains tested at MIC, however, a strain dependent behavior in presence of sub-MICs of ceftaroline was shown. In a second set of experiments, destruction of preformed biofilms by addition of ceftaroline was evaluated. Ceftaroline was able to inhibit biofilm formation at MIC in all strains tested but not at the sub-MICs. Destruction of preformed biofilms was strain dependent because the biofilm formed by a matrix-producing strain was resistant to a challenge with ceftaroline at MIC, whereas in other strains the biofilm was sensitive. At sub-MICs, the impact of ceftaroline on expression of virulence genes was strain-dependent at 1/4 MIC and no correlation between ceftaroline-enhanced biofilm formation and gene regulation was established at 1/16 MIC. Our findings suggest that sub-MICs of ceftaroline enhance bacterial attachment and biofilm formation by some, but not all, MRSA strains and, therefore, stress the importance of maintaining effective bactericidal concentrations of ceftaroline to fight biofilm-MRSA related infections.

  17. Dissemination of panton-valentine leukocidin-positive methicillin-resistant Staphylococcus aureus in Okinawa, Japan.

    PubMed

    Mine, Yoshiko; Nakasone, Isamu; Yamamoto, Yuichi; Utani, Atsushi; Yamane, Nobuhisa; Uezato, Hiroshi; Takahashi, Kenzo

    2013-01-01

    Panton-Valentine leukocidin (PVL) is a pore-forming cytotoxin that is produced by Staphylococcus aureus closely associated with skin and soft-tissue infections (SSTI). PVL-positive S. aureus strains have been identified worldwide, including in the USA; however, few studies have reported the presence of these strains in Japan. In this study, we prospectively investigated the prevalence of PVL in S. aureus strains from outpatients presenting with SSTI in Okinawa and characterized the PVL-positive S. aureus strains by polymerase chain reaction (PCR) and multilocus sequence typing (MLST). From 2008-2010, 499 clinical samples were obtained from 497 people. S. aureus was identified in 274 samples, and 36% (99 of 274) were methicillin-resistant S. aureus (MRSA). Seventeen (6.2%) PVL-positive S. aureus strains were detected by PCR, and 12 of the 17 PVL-positive strains were MRSA. Most PVL-positive S. aureus caused furuncles or carbuncles. Nine of the 17 PVL-positive isolates had an ST8 MRSA genotype and most harbored SCCmec type IVa and the arcA gene of the arginine catabolic mobile element, which is identical to the USA300 clone prevalent in the USA. PVL-positive S. aureus strains were more likely to be resistant to erythromycin (65%) and levofloxacin (53%). PVL-positive S. aureus strains have emerged and are spreading as a causative pathogen for SSTI in Okinawa.

  18. Prevalence and characteristics of community carriage of methicillin-resistant Staphylococcus aureus in Malta.

    PubMed

    Scerri, Jeanesse; Monecke, Stefan; Borg, Michael A

    2013-09-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen worldwide. Malta is one of the countries with the highest MRSA prevalence in Europe, as identified from hospital blood cultures [1]. However, community prevalence of MRSA has never previously been investigated. This study aimed at establishing the prevalence of community MRSA nasal colonization in Maltese individuals and identifying the clonal characteristics of the detected isolates. Nasal swabs were collected from 329 healthy individuals who were also asked to complete a brief questionnaire about risk factors commonly associated with MRSA carriage and infection. The swabs were transported and enriched in a nutrient broth supplemented with NaCl. The presence of MRSA was then determined by culturing on MRSA Select chromogenic agar and then confirming by several assays, including catalase, coagulase and PBP2a agglutination tests. The isolates were assayed for antibiotic susceptibilities and typed by microarray analysis to determine the clonal characteristics of each strain. The prevalence of MRSA nasal colonization in the healthy Maltese population was found to be 8.81% (95% confidence interval [CI], 5.75-11.87%), much higher than that found in other studies carried out in several countries. No statistical association was found between MRSA carriage and demographics or risk factors; however, this was hindered by the small sample size. Almost all the isolates were fusidic-acid resistant. The majority were found to belong to a local endemic clone (CC5) which seems to be replacing the previously prevalent European clone UK-EMRSA-15 in the country. A new clone (CC50-MRSA-V) was also characterized. The presence of such a significant community reservoir of MRSA increases the burdens already faced by the local healthcare system to control the MRSA epidemic. Colonization of MRSA in otherwise healthy individuals may represent a risk for endogenous infection and transmission to hospitalized

  19. Antibacterial Activity and Antibiotic-Enhancing Effects of Honeybee Venom against Methicillin-Resistant Staphylococcus aureus.

    PubMed

    Han, Sang Mi; Kim, Joung Min; Hong, In Pyo; Woo, Soon Ok; Kim, Se Gun; Jang, He Rye; Pak, Sok Cheon

    2016-01-12

    Methicillin-resistant Staphylococcus aureus (MRSA), along with other antibiotic resistant bacteria, has become a significant social and clinical problem. There is thus an urgent need to develop naturally bioactive compounds as alternatives to the few antibiotics that remain effective. Here we assessed the in vitro activities of bee venom (BV), alone or in combination with ampicillin, penicillin, gentamicin or vancomycin, on growth of MRSA strains. The antimicrobial activity of BV against MRSA strains was investigated using minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC) and a time-kill assay. Expression of atl which encodes murein hydrolase, a peptidoglycan-degrading enzyme involved in cell separation, was measured by reverse transcription-polymerase chain reaction. The MICs of BV were 0.085 µg/mL and 0.11 µg/mL against MRSA CCARM 3366 and MRSA CCARM 3708, respectively. The MBC of BV against MRSA 3366 was 0.106 µg/mL and that against MRSA 3708 was 0.14 µg/mL. The bactericidal activity of BV corresponded to a decrease of at least 3 log CFU/g cells. The combination of BV with ampicillin or penicillin yielded an inhibitory concentration index ranging from 0.631 to 1.002, indicating a partial and indifferent synergistic effect. Compared to ampicillin or penicillin, both MRSA strains were more susceptible to the combination of BV with gentamicin or vancomycin. The expression of atl gene was increased in MRSA 3366 treated with BV. These results suggest that BV exhibited antibacterial activity and antibiotic-enhancing effects against MRSA strains. The atl gene was increased in MRSA exposed to BV, suggesting that cell division was interrupted. BV warrants further investigation as a natural antimicrobial agent and synergist of antibiotic activity.

  20. Methicillin-Resistant Staphylococcus aureus Associated with Animals and Its Relevance to Human Health.

    PubMed

    Pantosti, Annalisa

    2012-01-01

    Staphylococcus aureus is a typical human pathogen. Some animal S. aureus lineages have derived from human strains following profound genetic adaptation determining a change in host specificity. Due to the close relationship of animals with the environmental microbiome and resistome, animal staphylococcal strains also represent a source of resistance determinants. Methicillin-resistant S. aureus (MRSA) emerged 50 years ago as a nosocomial pathogen but in the last decade it has also become a frequent cause of infections in the community. The recent finding that MRSA frequently colonizes animals, especially livestock, has been a reason for concern, as it has revealed an expanded reservoir of MRSA. While MRSA strains recovered from companion animals are generally similar to human nosocomial MRSA, MRSA strains recovered from food animals appear to be specific animal-adapted clones. Since 2005, MRSA belonging to ST398 was recognized as a colonizer of pigs and human subjects professionally exposed to pig farming. The "pig" MRSA was also found to colonize other species of farmed animals, including horses, cattle, and poultry and was therefore designated livestock-associated (LA)-MRSA. LA-MRSA ST398 can cause infections in humans in contact with animals, and can infect hospitalized people, although at the moment this occurrence is relatively rare. Other animal-adapted MRSA clones have been detected in livestock, such as ST1 and ST9. Recently, ST130 MRSA isolated from bovine mastitis has been found to carry a novel mecA gene that eludes detection by conventional PCR tests. Similar ST130 strains have been isolated from human infections in UK, Denmark, and Germany at low frequency. It is plausible that the increased attention to animal MRSA will reveal other strains with peculiar characteristics that can pose a risk to human health.

  1. Characterization of methicillin-resistant Staphylococcus aureus isolated from tertiary care hospitals in Tokyo, Japan.

    PubMed

    Nakaminami, Hidemasa; Noguchi, Norihisa; Ito, Ayumu; Ikeda, Masashi; Utsumi, Kenta; Maruyama, Hiroshi; Sakamoto, Haruo; Senoo, Masako; Takasato, Yoshio; Nishinarita, Susumu

    2014-08-01

    The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) remains problematic in both hospital and community settings. Investigations of MRSA existing in the local area are necessary to understand the detailed epidemiology of healthcare-associated MRSA (HA-MRSA). In the present study, molecular epidemiological analysis was performed on 584 MRSA isolated from four hospitals in Tokyo, Japan. In the pulsed-field gel electrophoresis (PFGE) analysis, four epidemic pulsotypes (I to IV) were found. The isolates of the epidemic pulsotype I mainly consisted of the SCCmec type II, toxic shock syndrome toxin 1 gene (tst)-negative, spa type t002, and ST764 clones. The ST764 clone, which is a novel hybrid variant of the ST5 HA-MRSA lineage with the arginine catabolic mobile element (ACME), was first found in Niigata, Japan. However, no ACME genes were detected in the isolates of the epidemic pulsotype I. In contrast, the other isolates of the epidemic pulsotypes mainly consisted of the SCCmec type II, tst-positive, spa type t002, and ST5 clones, which are the most predominant clones of HA-MRSA in Japan. Resistance rates of non-β-lactams for the isolates of the epidemic pulsotype I were higher than those of the other epidemic pulsotypes. Our data showed that the novel ACME-negative ST764 clones are being distributed throughout multiple hospitals in Tokyo. The ST764 clones in Tokyo have the potential to acquire ACME in the future, because the ACME-positive ST764 clones have already been found in both hospital and community settings in other areas of Japan.

  2. Antimicrobial photodynamic therapy for the decolonization of methicillin-resistant Staphylococcus aureus from the anterior nares

    NASA Astrophysics Data System (ADS)

    Street, Cale N.; Pedigo, Lisa; Gibbs, Aaron; Loebel, Nicolas G.

    2009-06-01

    The nosocomial infection rate has increased dramatically due to emergence of antibiotic resistant bacterial strains such as methicillin resistant Staphylococcus aureus (MRSA). The primary anatomical site of MRSA colonization is the anterior nares, and this reservoir represents a primary vector of transmission from non-infected carriers to susceptible individuals. Antimicrobial photodynamic therapy (aPDT) has been used successfully for topical disinfection in the oral cavity. The aim of this study was to evaluate the utility of aPDT for nasal MRSA decolonization at the preclinical and clinical level. The nasal aPDT system consists of a 670 nm diode laser fibre-optically coupled to a disposable light diffusing tip, used to activate a methylene blue based photosensitizer formulation. Preclinical testing was done both in a custom nasal reservoir model and on human skin cultures colonized on the epithelial surface with MRSA. Human clinical testing was performed by clinicians in regions in which the system is approved by the regulatory authority. In vitro testing demonstrated that aPDT eradicated planktonic MRSA in an energy and photosensitizer concentration dependent manner. Furthermore, aPDT eliminated sustained colonization of MRSA on cultured human epithelial surfaces, an effect that was sustained over multiple days post-treatment. In preliminary human testing, aPDT eradicated MRSA completely from the nose with total treatment times <10 minutes. aPDT is effective against MRSA when used topically in the nose. Energy dose and photosensitizer parameters have been optimized for the nasal environment. Controlled clinical studies are currently underway to further evaluate safety and efficacy.

  3. Methicillin-Resistant Staphylococcus aureus Clonal Types in the Czech Republic

    PubMed Central

    Melter, O.; Santos Sanches, I.; Schindler, J.; Aires de Sousa, M.; Mato, R.; Kovárova, V.; Zemlicková, H.; de Lencastre, H.

    1999-01-01

    Molecular surveillance studies have documented the extensive spread of methicillin-resistant Staphylococcus aureus (MRSA) clones. Studies carried out by Centro de Epidemiologia Molecular-Network for Tracking Gram-Positive Pathogenic Bacteria (CEM/NET) led to the identification of two international multidrug-resistant strains, which were designated as the Iberian and Brazilian MRSA clones and which were defined by multiple genomic typing methods; these included ClaI restriction digests hybridized with mecA- and Tn554-specific DNA probes and pulsed-field gel electrophoresis (PFGE). The genotypic characteristics of these clones are distinct: the Iberian clone is defined as mecA type I, Tn554 type E (or its variants), and PFGE pattern A (I:E:A), whereas the Brazilian clone is defined as mecA type XI (or its variants), Tn554 type B, and PFGE pattern B (XI:B:B). In this study, we characterized 59 single-patient isolates of MRSA collected during 1996 and 1997 at seven hospitals located in Prague and five other cities in the Czech Republic by using the methodologies mentioned above and by using ribotyping of EcoRI and HindIII digests hybridized with a 16S-23S DNA probe. The Brazilian MRSA clone (XI:B:B) was the major clone (80%) spread in two hospitals located in Prague and one located in Brno; the Iberian MRSA clone (I:E:A or its variant I:DD:A), although less representative (12%), was detected in two hospitals, one in Prague and the other in Plzen. Almost all the strains belonging to clone XI:B:B (45 of 47) corresponded to a unique ribotype, E1H1, whereas most strains of the I:E:A and I:DD:A clonal types (6 of 7) corresponded to ribotype E2H2. PMID:10449455

  4. EFFECT OF LINEZOLID ALONE AND IN COMBINATION WITH OTHER ANTIBIOTICS, ON METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS.

    PubMed

    Yehia, Hoda; El Said, Manal; Azmy, Magda; Badawy, Moushira; Mansy, Soheir; Gohar, Hamida; Madany, Nadia

    2016-04-01

    The prevalence of methicillin-resistant Staphyloccoccus aureus (MRSA) strains has presented a new challenge in antimicrobial medication. Linezolid is a new drug with potent activity on Gram-positive pathogens such as MRSA. The aim of the study was to investigate the in vitro activity of linezolid alone and in combination with imipenem, vancomycin or rifampicin to determine the most active therapy against MRSA strains. Twenty clinical MRSA strains were isolated from patients admitted to inpatient departments and outpatient clinics of Theodor Bilharz Research Institute. Standard strain MRSA ATCC 43300 was included as a control. The MICs of MRSA strains to linezolid, vancomycin, imipenem and rifampicin were evaluated using E test. Time-kill curve were used to assess the in vitro activity of linezolid (at 8x MIC) alone and in combination with imipenem (at 32x MIC), vancomycin or rifampicin (at 8x MIC). Scanning and transmission electron microscopy were performed to compare bacterial morphological alterations owing to the different combi- nations. Time-kill studies showed synergistic effect when linezolid combined with imipenem was tested against all the MRSA strains. Linezolid plus vancomycin or rifampicin combinations did not display any synergism or antagonism. Scanning and transmission electron microscopy observations confirmed the interactions observed in time kill experiments. Linezolid in combination with subinhibitory concentrations of imipenem can be bactericidal against MRSA strains and appears to be a promising combination for the treatment of MRSA infections. No synergistic activity was seen when the linezolid and vancomycin or rifampicin were combined. Linezolid could prevent the emergence of mutants resistant to rifampicin PMID:27363041

  5. Synergistic Effect between Cryptotanshinone and Antibiotics against Clinic Methicillin and Vancomycin-Resistant Staphylococcus aureus

    PubMed Central

    Cha, Jeong-Dan; Lee, Jeong-Ho; Choi, Kyung Min; Choi, Sung-Mi

    2014-01-01

    Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated strong antibacterial activity against clinic isolated methicillin and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA) in this experiment. The CT was determined against clinic isolated MRSA 1–16 with MIC and MBC values ranging from 4 to 32 and 8 to 128 μg/mL; for MSSA 1-2 from 16 to 32 μg/mL and 64 to 128 μg/mL; for VRSA 1-2 from 2 to 4 μg/mL and 4 to 16 μg/mL, respectively. The range of MIC50 and MIC90 of CT was 0.5–8 μg/mL and 4–64 μg/mL, respectively. The combination effects of CT with antibiotics were synergistic (FIC index <0.5) against most of tested clinic isolated MRSA, MSSA, and VRSA except additive, MRSA 4 and 16 in oxacillin, MRSA 6, 12, and 15 in ampicillin, and MRSA 6, 11, and 15 in vancomycin (FIC index < 0.75–1.0). Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 2–6 h of treatment with the 1/2 MIC of CT, regardless of whether it was administered alone or with ampicillin, oxacillin, or vancomycin. The results suggest that CT could be employed as a natural antibacterial agent against multidrug-resistant pathogens infection. PMID:24782909

  6. Effects of Subinhibitory Concentrations of Ceftaroline on Methicillin-Resistant Staphylococcus aureus (MRSA) Biofilms

    PubMed Central

    Rodríguez-Mirones, Cristina; Acosta, Felix; Icardo, Jose M.; Martínez-Martínez, Luis; Ramos-Vivas, José

    2016-01-01

    Ceftaroline (CPT) is a novel cephalosporin with in vitro activity against Staphylococcus aureus. Ceftaroline exhibits a level of binding affinity for PBPs in S. aureus including PBP2a of methicillin-resistant S. aureus (MRSA). The aims of this study were to investigate the morphological, physiological and molecular responses of MRSA clinical strains and MRSA biofilms to sub-MICs (1/4 and 1/16 MIC) of ceftaroline by using transmission, scanning and confocal microscopy. We have also used quantitative Real-Time PCR to study the effect of sub-MICs of ceftaroline on the expression of the staphylococcal icaA, agrA, sarA and sasF genes in MRSA biofilms. In one set of experiments, ceftaroline was able to inhibit biofilm formation in all strains tested at MIC, however, a strain dependent behavior in presence of sub-MICs of ceftaroline was shown. In a second set of experiments, destruction of preformed biofilms by addition of ceftaroline was evaluated. Ceftaroline was able to inhibit biofilm formation at MIC in all strains tested but not at the sub-MICs. Destruction of preformed biofilms was strain dependent because the biofilm formed by a matrix-producing strain was resistant to a challenge with ceftaroline at MIC, whereas in other strains the biofilm was sensitive. At sub-MICs, the impact of ceftaroline on expression of virulence genes was strain-dependent at 1/4 MIC and no correlation between ceftaroline-enhanced biofilm formation and gene regulation was established at 1/16 MIC. Our findings suggest that sub-MICs of ceftaroline enhance bacterial attachment and biofilm formation by some, but not all, MRSA strains and, therefore, stress the importance of maintaining effective bactericidal concentrations of ceftaroline to fight biofilm-MRSA related infections. PMID:26800524

  7. Carriage of methicillin-resistant Staphylococcus aureus by wild urban Norway rats (Rattus norvegicus).

    PubMed

    Himsworth, Chelsea G; Miller, Ruth R; Montoya, Vincent; Hoang, Linda; Romney, Marc G; Al-Rawahi, Ghada N; Kerr, Thomas; Jardine, Claire M; Patrick, David M; Tang, Patrick; Weese, J Scott

    2014-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of multi-drug-resistant infections in people, particularly indigent populations. MRSA can be transmitted between people and domestic animals, but the potential for transmission between people and commensal pests, particularly rodents, had not been investigated. The objective of this study was to identify the presence and characterize the ecology of MRSA in rats (Rattus spp.) from in an impoverished, inner-city neighborhood. Oropharyngeal swabs were collected from rats trapped in 33 city blocks and one location within the adjacent port. Bacterial culture was performed and MRSA isolates were characterized using a variety of methods, including whole-genome sequencing (WGS). The ecology of MRSA in rats was described using phylogenetic analysis, geospatial analysis, and generalized linear mixed models. MRSA was identified 22 of 637 (3.5%) rats tested, although prevalence varied from 0 - 50% among blocks. Isolates belonged to 4 clusters according to WGS, with the largest cluster (n = 10) containing isolates that were genetically indistinguishable from community-acquired USA300 MRSA strains isolated from people within the study area. MRSA strains demonstrated both geographic clustering and dispersion. The odds of an individual rat carrying MRSA increased with increased body fat (OR = 2.53, 95% CI = 1.33-4.82), and in the winter (OR = 5.29, 95% CI = 1.04-26.85) and spring (OR = 5.50, 95% CI = 1.10-27.58) compared to the fall. The results show that urban rats carried the same MRSA lineages occurring in local human and/or animal populations, supporting recent transmission from external sources. MRSA carriage was influenced by season, most likely as a result of temporal variation in rat behavior and rat-human interactions.

  8. Use of a multiplex molecular beacon platform for rapid detection of methicillin and vancomycin resistance in Staphylococcus aureus.

    PubMed

    Sinsimer, Daniel; Leekha, Surbhi; Park, Steven; Marras, Salvatore A E; Koreen, Larry; Willey, Barbara; Naidich, Steve; Musser, Kimberlee A; Kreiswirth, Barry N

    2005-09-01

    Drug resistance, particularly vancomycin and methicillin resistance, in Staphylococcus aureus continues to emerge as a significant public health threat in both the hospital and community settings. In addition to the limited treatment options, S. aureus strains acquire and express numerous virulence factors that continue to increase its ability to cause a wide spectrum of human disease. As a result, empirical treatment decisions are confounded and there is a heightened need for a diagnostic test (or assay) to rapidly identify antibiotic resistance and specific virulence determinants and indicate the appropriate treatment. To that end we developed a platform using multiplex molecular beacon probes with real-time PCR for the rapid detection of drug resistance-determining genes and virulence factors in S. aureus. In this study, we demonstrate the specificity and sensitivity of our platform for detection of the genes conferring methicillin (mecA) and vancomycin (vanA) resistance as well as a gene encoding the virulence factor Panton-Valentine leucocidin (lukF) in S. aureus isolates.

  9. Metabolic pathway analysis approach: identification of novel therapeutic target against methicillin resistant Staphylococcus aureus.

    PubMed

    Uddin, Reaz; Saeed, Kiran; Khan, Waqasuddin; Azam, Syed Sikander; Wadood, Abdul

    2015-02-10

    Multiple Drug Resistant (MDR) bacteria are no more inhibited by the front line antibiotics due to extreme resistance. Methicillin Resistant Staphylococcus aureus (MRSA) is one of the MDR pathogens notorious for its widespread infection around the world. The high resistance acquired by MRSA needs a serious concern and efforts should be carried out for the discovery of better therapeutics. With this aim, we designed a comparison of the metabolic pathways of the pathogen, MRSA strain 252 (MRSA252) with the human host (i.e., Homo sapiens) by using well-established in silico methods. We identified several metabolic pathways unique to MRSA (i.e., absent in the human host). Furthermore, a subtractive genomics analysis approach was applied for retrieval of proteins only from the unique metabolic pathways. Subsequently, proteins of unique MRSA pathways were compared with the host proteins. As a result, we have shortlisted few unique and essential proteins that could act as drug targets against MRSA. We further assessed the druggability potential of the shortlisted targets by comparing them with the DrugBank Database (DBD). The identified drug targets could be useful for an effective drug discovery phase. We also searched the sequences of unique as well as essential enzymes from MRSA in Protein Data Bank (PDB). We shortlisted at least 12 enzymes for which there was no corresponding deposition in PDB, reflecting that their crystal structures are yet to be solved! We selected Glutamate synthase out of those 12 enzymes owing to its participation in significant metabolic pathways of the pathogen e.g., Alanine, Aspartate, Glutamate and Nitrogen metabolism and its evident suitability as drug target among other MDR bacteria e.g., Mycobacteria. Due to the unavailability of any crystal structure of Glutamate synthase in PDB, we generated the 3D structure by homology modeling. The modeled structure was validated by multiple analysis tools. The active site of Glutamate synthase was

  10. Comparison of Outcomes among Adult Patients with Nosocomial Bacteremia Caused by Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus: A Retrospective Cohort Study

    PubMed Central

    Wang, Jann-Tay; Hsu, Le-Yin; Lauderdale, Tsai-Ling; Fan, Wen-Chien; Wang, Fu-Der

    2015-01-01

    Several studies have shown that patients with bacteremia caused by methicillin-resistant Staphylococcus aureus (MRSA) have worse outcomes than those with bacteremia caused by methicillin-susceptible S. aureus (MSSA). However, only a limited number of studies have stratified the MRSA isolates into healthcare-associated (HA-) and community-associated (CA-) MRSA strains in such a comparison. This three-year retrospective cohort study, enrolling adult patients with nosocomial S. aureus bacteremia (SAB), was designed to investigate whether CA-MRSA and/or HA-MRSA strains were associated with different outcomes in comparison to MSSA in such a setting. The drug susceptibilities and staphylococcal cassette chromosome mec (SCCmec) types were determined for all of the causative isolates available. The MRSA bacteremia was further categorized into those caused by CA-MRSA strains (CA-MRSA-S bacteremia) when the causative isolates carried the type IV or V SCCmec element, those caused by HA-MRSA strains (HA-MRSA-S bacteremia) when the isolates carried the type I, II, or III SCCmec element, or unclassified MRSA bacteremia when the isolates were not available. The relevant demographic, clinical, and laboratory data were collected by reviewing the patients’ charts. The primary outcome was all-cause in-hospital mortality. A total of 353 patients were studied. The overall in-hospital mortality rate was 32.6%, with 23.3% in MSSA, 30.5% in CA-MRSA-S, 47.5% in HA-MRSA-S, and 35.3% in unclassified MRSA bacteremia, respectively. The multivariate analysis showed that HA-MRSA-S, but not CA-MRSA-S, bacteremia was associated with a significantly worse outcome compared with MSSA. The other risk factors independently associated with all-cause in-hospital mortality included the Charlson co-morbidity index, septic shock, thrombocytopenia, and persistent bacteremia. Resistance to linezolid and daptomycin was found among the MRSA isolates. The present study showed that bacteremia caused by HA

  11. Methicillin-Resistant Staphylococcus capitis with Reduced Vancomycin Susceptibility Causes Late-Onset Sepsis in Intensive Care Neonates

    PubMed Central

    Rasigade, Jean-Philippe; Raulin, Olivia; Picaud, Jean-Charles; Tellini, Charlotte; Bes, Michele; Grando, Jacqueline; Ben Saïd, Mohamed; Claris, Olivier; Etienne, Jerome; Tigaud, Sylvestre; Laurent, Frederic

    2012-01-01

    Background Coagulase-negative staphylococci, mainly Staphylococcus epidermidis, are the most frequent cause of late-onset sepsis (LOS) in the neonatal intensive care unit (NICU) setting. However, recent reports indicate that methicillin-resistant, vancomycin-heteroresistant Staphylococcus capitis could emerge as a significant pathogen in the NICU. We investigated the prevalence, clonality and vancomycin susceptibility of S. capitis isolated from the blood of NICU infants and compared these data to adult patients. Methodology/Principal Findings We conducted a retrospective laboratory-based survey of positive blood cultures in NICU infants ≥3 days of age (n = 527) and in adult ICU patients ≥18 years of age (n = 1473) who were hospitalized from 2004 to 2009 in two hospital centers in Lyon, France. S. capitis was the most frequent pathogen in NICU infants, ahead of S. epidermidis (39.1% vs. 23.5% of positive blood cultures, respectively). Conversely, S. capitis was rarely found in adult ICU patients (1.0%) compared to S. epidermidis (15.3%). S. capitis bloodstream isolates were more frequently resistant to methicillin when collected from NICU infants than from adult patients (95.6% vs. 53.3%, respectively). Furthermore, we collected and characterized 53 S. capitis bloodstream isolates from NICU infants and adult patients from six distant cities. All methicillin-resistant S. capitis isolates from NICU infants were clonally related as determined by pulsed-field gel electrophoresis. These isolates harbored a type V-related staphylococcal chromosomal cassette mec element, and constantly showed either vancomycin resistance (37.5%) or heteroresistance (62.5%). Conversely, the isolates that were collected outside of the NICU were genetically diverse and displayed much lower rates of vancomycin resistance and heteroresistance (7.7% and 23.1%, respectively). Conclusions/Significance A clonal population of methicillin-resistant S. capitis strains has spread into

  12. Characterization of methicillin-susceptible and -resistant staphylococci in the clinical setting: a multicentre study in Nigeria

    PubMed Central

    2012-01-01

    Background The staphylococci are implicated in a variety of human infections; however, many clinical microbiology laboratories in Nigeria do not identify staphylococci (in particular coagulase negative staphylococci - CNS) to the species level. Moreover, data from multi-centre assessment on antibiotic resistance and epidemiology of the staphylococci are not available in Nigeria. This study investigated 91 non-duplicate staphylococcal isolates obtained from the microbiology laboratories of eight hospitals in Nigeria during the period January to April 2010. Methods Identification and antibiotic susceptibility testing was performed using the VITEK 2 system, detection of resistance genes by PCR, and molecular characterization was determined by SCCmec typing, spa and multilocus sequence typing (MLST). Results All the isolates were susceptible to mupirocin, tigecycline, vancomycin and linezolid, but 72.5% of CNS and 82.3% of Staphylococcus aureus were resistant to cotrimoxazole, while multiresistance was observed in 37 of the 40 CNS isolates. Untypeable SCCmec types (ccrC/Class A mec and ccr-negative/Class C2 mec gene complex) in two methicillin-resistant S. aureus (MRSA) were identified. Additionally, ccr-negative/Class A mec and ccr type 4/Class C2 mec gene complex was detected in one isolate each of S. sciuri and S. haemolyticus, respectively. The S. aureus isolates were classified into 21 spa types including two new types (t8987, t9008) among the methicillin-susceptible S. aureus (MSSA) isolates. Two (CC8-SCCmecnon-typeable and CC88-SCCmec IV) and four (CC8-SCCmec III/IV/V; CC30-SCCmec II/III; CC88-SCCmec IV; and ST152-SCCmecnon-typeable) MRSA clones were identified in Maiduguri (North-East Nigeria) and South-West Nigeria, respectively. The proportion of Panton-Valentine leukocidin (PVL)-positive MSSA was high (44.4%) and 56.3% of these strains were associated with sequence type (ST) 152. Conclusions The identification of multiresistant mecA positive S. haemolyticus

  13. Clinical impact of antimicrobial resistance in European hospitals: excess mortality and length of hospital stay related to methicillin-resistant Staphylococcus aureus bloodstream infections.

    PubMed

    de Kraker, Marlieke E A; Wolkewitz, Martin; Davey, Peter G; Koller, Walter; Berger, Jutta; Nagler, Jan; Icket, Claudine; Kalenic, Smilja; Horvatic, Jasminka; Seifert, Harald; Kaasch, Achim J; Paniara, Olga; Argyropoulou, Athina; Bompola, Maria; Smyth, Edmond; Skally, Mairead; Raglio, Annibale; Dumpis, Uga; Kelmere, Agita Melbarde; Borg, Michael; Xuereb, Deborah; Ghita, Mihaela C; Noble, Michelle; Kolman, Jana; Grabljevec, Stanko; Turner, David; Lansbury, Louise; Grundmann, Hajo

    2011-04-01

    Antimicrobial resistance is threatening the successful management of nosocomial infections worldwide. Despite the therapeutic limitations imposed by methicillin-resistant Staphylococcus aureus (MRSA), its clinical impact is still debated. The objective of this study was to estimate the excess mortality and length of hospital stay (LOS) associated with MRSA bloodstream infections (BSI) in European hospitals. Between July 2007 and June 2008, a multicenter, prospective, parallel matched-cohort study was carried out in 13 tertiary care hospitals in as many European countries. Cohort I consisted of patients with MRSA BSI and cohort II of patients with methicillin-susceptible S. aureus (MSSA) BSI. The patients in both cohorts were matched for LOS prior to the onset of BSI with patients free of the respective BSI. Cohort I consisted of 248 MRSA patients and 453 controls and cohort II of 618 MSSA patients and 1,170 controls. Compared to the controls, MRSA patients had higher 30-day mortality (adjusted odds ratio [aOR] = 4.4) and higher hospital mortality (adjusted hazard ratio [aHR] = 3.5). Their excess LOS was 9.2 days. MSSA patients also had higher 30-day (aOR = 2.4) and hospital (aHR = 3.1) mortality and an excess LOS of 8.6 days. When the outcomes from the two cohorts were compared, an effect attributable to methicillin resistance was found for 30-day mortality (OR = 1.8; P = 0.04), but not for hospital mortality (HR = 1.1; P = 0.63) or LOS (difference = 0.6 days; P = 0.96). Irrespective of methicillin susceptibility, S. aureus BSI has a significant impact on morbidity and mortality. In addition, MRSA BSI leads to a fatal outcome more frequently than MSSA BSI. Infection control efforts in hospitals should aim to contain infections caused by both resistant and susceptible S. aureus.

  14. A preliminary evaluation of a new selective agar supplemented with desferrioxamine for detection of methicillin-resistant Staphylococcus aureus.

    PubMed

    Monsen, T; Olofsson, C; Granström, S; Wiström, J

    2003-07-01

    The aim of the present study was to evaluate the performance of two new selective screening agars, Colombia agar supplemented with 1000 mg/L desferrioxamine, 5 mg/L amphotericin B, 16 mg/L polymyxin B, and 2 mg/L methicillin (CMDAP agar) or 0.5 mg/L oxacillin (CODAP agar), for detection of methicillin-resistant Staphylococcus aureus (MRSA). Both the CMDAP and the CODAP agar effectively inhibited growth of 151 isolates of coagulase-negative staphylococci (CoNS), 45 of Enterobacteriaceae and six Candida spp. examined. The sensitivity and specificity of the CMDAP and CODAP agars for detection of MRSA was calculated by comparing the growth of 52 MRSA with the inhibition of 74 mecA negative S. aureus and of 151 CoNS. The performance of the new agars was compared with four previously described MRSA screening agars. The sensitivity and specificity for detection of MRSA after incubation at 35 degrees C for 24 h was 0.94 and 0.91, respectively, for the CMDAP agar, 0.60 and 0.90 for the CODAP agar, 0.98 and 0.57 for methicillin aztreonam mannitol salt agar (MAMSA), 0.23 and 0.84 for oxacillin mannitol salt agar (OMSA), 0.48 and 0.76 for oxacillin Mueller-Hinton agar (OMHA) and 0.75 and 0.77 for lithium oxacillin mannitol salt agar (LOMSA). Agars supplemented with desferrioxamine, CMDAP and CODAP, were more specific for detecting MRSA compared with agars not supplemented with desferrioxamine. The detection rate was higher for agars supplemented with methicillin than for agars supplemented with oxacillin.

  15. The evolution of methicillin-resistant Staphylococcus aureus in Canadian hospitals: 5 years of national surveillance

    PubMed Central

    Simor, Andrew E.; Ofner-Agostini, Marianna; Bryce, Elizabeth; Green, Karen; McGeer, Allison; Mulvey, Michael; Paton, Shirley

    2001-01-01

    Background To better understand the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in Canadian hospitals, surveillance has been conducted in sentinel hospitals across the country since 1995. We report the results of the first 5 years of the program. Methods For each newly identified inpatient with MRSA, medical records were reviewed for demographic and clinical data. Isolates were subjected to susceptibility testing and molecular typing by pulsed-field gel electrophoresis. Results A total of 4507 patients infected or colonized with MRSA were identified between January 1995 and December 1999. The rate of MRSA increased each year from a mean of 0.95 per 100 S. aureus isolates in 1995 to 5.97 per 100 isolates in 1999 (0.46 per 1000 admissions in 1995 to 4.12 per 1000 admissions in 1999) (p < 0.05). Most of the increase in MRSA occurred in Ontario, Quebec and the western provinces. Of the 3009 cases for which the site of MRSA acquisition could be determined, 86% were acquired in a hospital, 8% were acquired in a long-term care facility and 6% were acquired in the community. A total of 1603 patients (36%) were infected with MRSA. The most common sites of infection were skin or soft tissue (25% of MRSA infections), pulmonary tissues (24%) and surgical sites (23%); 13% of the patients were bacteremic. An epidemiologic link with a previously identified MRSA patient was suspected in 53% of the cases. Molecular typing indicated that most (81%) of the isolates could be classified as related to 1 of the 4 Canadian epidemic strains of MRSA. Interpretation There has been a significant increase in the rate of isolating MRSA in many Canadian hospitals, related to the transmission of a relatively small number of MRSA strains. PMID:11468949

  16. Sonodynamic action of hypocrellin B on methicillin-resistant Staphylococcus aureus.

    PubMed

    Wang, Xinna; Ip, Margaret; Leung, Albert Wingnang; Wang, Pan; Zhang, Hongwei; Hua, Heyu; Xu, Chuanshan

    2016-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) commonly causes refractory infections and has recently become a serious public health concern. The present study was designed to investigate sonodynamic action of hypocrellin B on MRSA. A MRSA strain (ATCC BAA-43) was used in the present study. The dark toxicity of hypocrellin B on MRSA and its uptake in MRSA first were measured. And then bacteria were incubated with hypocrellin B and exposed to ultrasound. After sonodynamic treatment, colony forming unit assay and bacterial viability assay were conducted. Membrane permeability assay, DNA fragmentation assay, and DNA synthesis assay were also performed to examine the underlying mechanism. The results showed that hypocrellin B at concentrations of up to 500 μM had no toxicity to MRSA in the dark. After incubation for 50 min, hypocrellin B could be maximally absorbed by MRSA, and exhibited significant sonodynamic activity in a dose-dependent manner. The 5-log reduction in colony forming unit (CFU) was observed after hypocrellin B (40 μM) treatment at an intensity of 1.38 W/cm(2) ultrasound for 5 min. Compared to the control, hypocrellin B alone and ultrasound sonication alone group, more dead cells were found and bacterial membrane integrity was notably damaged after sonodynamic treatment of hypocrellin B. However, no remarkable DNA damage was found in MRSA after sonodynamic treatment of hypocrellin B. All the findings demonstrated that hypocrellin B could serve as a potential antibacterial sonosensitizer to significantly cause damage to the membrane integrity of MRSA and inhibit its growth under ultrasound sonication.

  17. Predictive value of methicillin-resistant Staphylococcus aureus (MRSA) nasal swab PCR assay for MRSA pneumonia.

    PubMed

    Dangerfield, Benjamin; Chung, Andrew; Webb, Brandon; Seville, Maria Teresa

    2014-01-01

    Pneumonia due to methicillin-resistant Staphylococcus aureus (MRSA) is associated with poor outcomes and frequently merits empirical antibiotic consideration despite its relatively low incidence. Nasal colonization with MRSA is associated with clinical MRSA infection and can be reliably detected using the nasal swab PCR assay. In this study, we evaluated the performance of the nasal swab MRSA PCR in predicting MRSA pneumonia. A retrospective cohort study was performed in a tertiary care center from January 2009 to July 2011. All patients with confirmed pneumonia who had both a nasal swab MRSA PCR test and a bacterial culture within predefined time intervals were included in the study. These data were used to calculate sensitivity, specificity, positive predictive value, and negative predictive value for clinically confirmed MRSA pneumonia. Four hundred thirty-five patients met inclusion criteria. The majority of cases were classified as either health care-associated (HCAP) (54.7%) or community-acquired (CAP) (34%) pneumonia. MRSA nasal PCR was positive in 62 (14.3%) cases. MRSA pneumonia was confirmed by culture in 25 (5.7%) cases. The MRSA PCR assay demonstrated 88.0% sensitivity and 90.1% specificity, with a positive predictive value of 35.4% and a negative predictive value of 99.2%. In patients with pneumonia, the MRSA PCR nasal swab has a poor positive predictive value but an excellent negative predictive value for MRSA pneumonia in populations with low MRSA pneumonia incidence. In cases of culture-negative pneumonia where initial empirical antibiotics include an MRSA-active agent, a negative MRSA PCR swab can be reasonably used to guide antibiotic de-escalation.

  18. Methicillin-resistant Staphylococcus aureus risk profiling: who are we missing?

    PubMed Central

    2013-01-01

    Background Targeted screening of patients at high risk for methicillin-resistant Staphylococcus aureus (MRSA) carriage is an important component of MRSA control programs, which rely on prediction tools to identify those high-risk patients. Most previous risk studies reported a substantial rate of patients who are eligible for screening, but failed to be enrolled. The characteristics of these missed patients are seldom described. We aimed to determine the rate and characteristics of patients who were missed by a MRSA screening programme at our institution to see how the failure to include these patients might impact the accuracy of clinical prediction tools. Findings From March-June 2010 all patients admitted to 13 internal medicine wards at the University of Geneva Hospital (HUG) were prospectively screened for MRSA carriage. Of 1968 patients admitted to the ward, 267 patients (13.6%) failed to undergo appropriate MRSA screening. Forty-one (2.4%) screened patients were MRSA carriers at admission. On multivariate regression, patients who were missed by screening were more likely to be aged < 50 years (OR 2.4 [1.4-3.9]), transferred to internal medicine from another ward in the hospital (OR 2.8 [1.1-7.1]), and have a history of malignancy (OR 3.2[2.1-5.1]). There was no significant difference in the rate of previous MRSA carriage between screened and unscreened patients. Conclusions Our findings highlight the potential bias that “missed” patients may introduce into MRSA risk scores. Reporting on the proportions and characteristics of missed patients is essential for accurate interpretation of MRSA prediction tools. PMID:23721630

  19. Methicillin resistance gene diversity in staphylococci isolated from captive and free-ranging wallabies

    PubMed Central

    Chen, Michelle M. S.; Boardman, Wayne S. J.; Brown, Melissa H.

    2016-01-01

    Background Infection with methicillin-resistant staphylococci (MRS) can be life-threatening in humans and its presence in animals is a cause for public health concern. The aim of this study was to measure the prevalence of MRS in captive and free-ranging wallabies over a 16-month period in South Australia, Australia. Materials and methods Eighty-nine purified staphylococcal isolates recovered from 98 captive and free-ranging wallabies' anterior nasal swabs were used in this study. All isolates were tested for the presence of the mecA, mecA1, and mecC genes. Multiplex PCR-directed SCCmec-typing, ccrB-typing, and determination of the minimal inhibitory concentration of oxacillin were performed on mec-positive isolates. Results and discussion In total, 11 non-Staphylococcus aureus MRS were isolated from 7 out of 98 animals, corresponding to a 7.1% carriage rate. The SCCmec types I, III, and V were identified by multiplex PCR and sequencing of the ccrB gene. This is the first report of MRS carriage in both captive and free-ranging wallabies in Australia. These data demonstrate a low prevalence of MRS and no association between wallaby captivity status and MRS carriage could be assigned. These animals may act as a reservoir for the exchange of genetic elements between staphylococci. Furthermore, the mecA genes of animal isolates were identical to that found in human MRS strains and thus the possibility of zoonotic transfer must be considered. PMID:27193419

  20. Oxacillin alters the toxin expression profile of community-associated methicillin-resistant Staphylococcus aureus.

    PubMed

    Rudkin, Justine K; Laabei, Maisem; Edwards, Andrew M; Joo, Hwang-Soo; Otto, Michael; Lennon, Katrina L; O'Gara, James P; Waterfield, Nicholas R; Massey, Ruth C

    2014-01-01

    The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a growing cause for concern. These strains are more virulent than health care-associated MRSA (HA-MRSA) due to higher levels of toxin expression. In a previous study, we showed that the high-level expression of PBP2a, the alternative penicillin binding protein encoded by the mecA gene on type II staphylococcal cassette chromosome mec (SCCmec) elements, reduced toxicity by interfering with the Agr quorum sensing system. This was not seen in strains carrying the CA-MRSA-associated type IV SCCmec element. These strains express significantly lower levels of PBP2a than the other MRSA type, which may explain their relatively high toxicity. We hypothesized that as oxacillin is known to increase mecA expression levels, it may be possible to attenuate the toxicity of CA-MRSA by using this antibiotic. Subinhibitory oxacillin concentrations induced PBP2a expression, repressed Agr activity, and, as a consequence, decreased phenol-soluble modulin (PSM) secretion by CA-MRSA strains. However, consistent with other studies, oxacillin also increased the expression levels of alpha-toxin and Panton-Valentine leucocidin (PVL). The net effect of these changes on the ability to lyse diverse cell types was tested, and we found that where the PSMs and alpha-toxin are important, oxacillin reduced overall lytic activity, but where PVL is important, it increased lytic activity, demonstrating the pleiotropic effect of oxacillin on toxin expression by CA-MRSA.

  1. Methicillin-resistant Staphylococcus aureus phage plaque size enhancement using sublethal concentrations of antibiotics.

    PubMed

    Kaur, Sandeep; Harjai, Kusum; Chhibber, Sanjay

    2012-12-01

    Phage therapy presents an alternative approach against the emerging methicillin-resistant Staphylococcus aureus (MRSA) threat. Some of the problems encountered during isolation of MRSA phages include the high prevalence of enteric phages in natural sources, nonspecific absorption of viable phage, and the formation of pinpoint or tiny plaques. The phage isolated in this study, MR-5, also formed tiny plaques against its host S. aureus ATCC 43300 (MRSA), making its detection and enumeration difficult. An improved method of increasing the plaque size of MRSA phage by incorporating sublethal concentrations of three different classes of antibiotics (inhibitors of protein synthesis) in the classical double-layer agar (DLA) method was investigated. The β-lactam and quinolone antibiotics commonly employed in earlier studies for increasing the plaque size did not show any significant effect on the plaque size of isolated MR-5 phage. Linezolid (oxazolidinone class), tetracycline, and ketolide antibiotics brought significant enhancements (3 times the original size) in the plaque size of MR-5 phage. Prior treatment with these antibiotics resulted in significant reductions in the time of adsorption and the latent period of MR-5 phage. To rule out whether the action of linezolid (which brought the maximum increase in plaque size) was specific for a single phage only, its effect on the plaque size of seven other S. aureus-specific phages was also assessed. Significant enhancements in the plaque size of these phages were observed. These results indicate that this modification can therefore safely be incorporated in the traditional DLA overlay method to search for new MRSA-virulent phages. PMID:23001655

  2. [Septicemia due to methicillin-resistant Staphylococcus aureus from chronic prurigo in an elderly woman].

    PubMed

    Saeki, H; Muneta, S; Kobayashi, T; Hirota, Y

    1997-08-01

    An 80-year-old woman being treated with anti-hypertensive drugs developed eruption and itching of the skin. High fever and lymph node enlargement subsequently developed in spite of discontinuing all antihypertensive drugs, and she was admitted to our hospital. At the initial examination, multiple papules were noted over the entire body, and the skin showed thickening and lichenification with scratch marks. There was also generalized enlargement of the superficial lymph nodes. From these findings, her condition was diagnosed as chronic prurigo due to drug allergy. Laboratory tests showed inflammatory findings, anemia and a high serum level of IgE. Analysis of the surface marker of peripheral lymphocytes revealed no abnormalities. Bacteriologic cultures of blood revealed methicillin-resistant Staphylococcus aureus (MRSA). Histologic examination of the lymph nodes revealed chronic reactive lymphadenitis with a follicular pattern. She was strongly suspected of having MRSA septicemia, and so combination chemotherapy with vancomycin, minocycline and cefoperazone/sulbactam was started. However, 1 month after initiation of chemotherapy, the low-grade fever, eruption and moderate inflammatory findings persisted, and culture of the eruptions revealed MRSA. The prurigo was therefore considered to be the source of the septicemia, and daily application of diflucortolone ointment containing 3% acetic acid was started. Thereafter, the clinical and laboratory findings showed a rapid improvement. MRSA infections usually occur in compromised patients who are receiving antibiotics during prolonged hospitalization. The present case, who did not have any underlying disease, indicates that old-age is also an important factor for the development of MRSA septicemia. PMID:9396325

  3. Effectiveness of various hospital-based solutions against community- acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Perona, Paul J; Johnson, Aaron J; Perona, John P; Issa, Kimona; Kapadia, Bhaveen H; Bonutti, Peter M; Mont, Michael A

    2013-01-01

    Periprosthetic infections with methicillin-resistant Staphylococcus aureus (MRSA) can be particularly burdensome and difficult to eradicate. One of the measures that infection control officers have emphasized in our hospitals has been the use of various hand sanitizers throughout the hospital. Our objective was to determine the level of growth inhibition of common hand sanitizers and surgical scrub solutions that are used to prevent the spread of community-acquired strains of MRSA. Various hospital and surgical agents (n = 13) were applied to community-acquired MRSA bacteria that had been cultured on agar plates. These different commercially available solutions were incubated for 48 h, and the plates were assessed to determine the level of growth inhibition (0, 25, 75, or 100%). The negative control was a test in which no agent was added to the MRSA culture, while a positive control tested 100% alcohol. Eight of the solutions tested had 100% growth inhibition, four solutions had partial growth inhibition effects, and one solution did not inhibit MRSA. Of the solutions with alcohol, the 62% solution did not kill MRSA, while the 80% solution only inhibited MRSA. Both the 95 and 100% alcohol solutions had 100% growth inhibition. Of the two surgical scrub solutions, only the one with iodine had 100% growth inhibition, whereas the solution with chloroxylenol (PCMX 3%) had only partial growth inhibition. This study suggests that the solutions with high levels of alcohol, chlorhexidine, or iodine appear to better kill MRSA and might best be used to prevent the spread of community-acquired MRSA in both the hospital and the surgical environment. PMID:24266441

  4. Colonization of butchers with livestock-associated methicillin-resistant Staphylococcus aureus.

    PubMed

    Boost, M; Ho, J; Guardabassi, L; O'Donoghue, M

    2013-12-01

    Reports have documented colonization of swine in Europe, North America and more recently in China with livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA). Contamination of pig farmers, veterinarians and abattoir workers with these strains has been observed. However, although contamination levels of 10% of retail pork were reported from the Netherlands and Canada, there are limited data of contamination rates of workers handling raw meat. We investigated the rates of MRSA contamination of local butchers working in wet markets, where recently slaughtered pigs are cut up. Nasal swabs collected from 300 pork butchers at markets throughout Hong Kong were enriched in brain heart infusion broth with 5% salt and cultured on MRSASelect(®) . Isolates were confirmed as Staphylococcus aureus and susceptibility testing performed. The presence of mecA was confirmed, SCCmec and spa type determined and relatedness investigated by PFGE. Subjects completed a questionnaire on MRSA carriage risk factors. Seventeen samples (5.6%) yielded MRSA, 15 harbouring SCCmec IVb. Ten strains were t899 (CC9), previously reported from local pig carcasses. Five strains were healthcare associated: SCCmec type II, t701(CC6), colonizing two subjects at the same establishment, and single isolates of t008 (CC8), t002 (CC5) and t123 (CC45). The remaining isolates were t359 (CC97), previously reported from buffaloes, and t375 (CC5), reported from bovine milk. None of these butchers reported recent hospitalization or a healthcare worker in the family. Two had recently received antibiotics, one for a skin infection. Four reported wound infections within the last year. All were exposed to meat for >9 h per day. Carriage of MRSA was higher in butchers than in the general community. Although five strains were probably of healthcare origin, the high incidence of t899 (CC9) suggests that cross-contamination from pork occurs frequently. Washing of hands after touching raw pork is advised.

  5. Control of Methicillin-Resistant Staphylococcus aureus Pneumonia Utilizing TLR2 Agonist Pam3CSK4.

    PubMed

    Chen, Yi-Guo; Zhang, Yong; Deng, Lin-Qiang; Chen, Hui; Zhang, Yu-Juan; Zhou, Nan-Jin; Yuan, Keng; Yu, Li-Zhi; Xiong, Zhang-Hua; Gui, Xiao-Mei; Yu, Yan-Rong; Wu, Xiao-Mu; Min, Wei-Ping

    2016-01-01

    The spread of methicillin-resistant Staphylococcus aureus (MRSA) is a critical health issue that has drawn greater attention to the potential use of immunotherapy. Toll-like receptor 2 (TLR2), a pattern recognition receptor, is an essential component in host innate defense system against S. aureus infection. However, little is known about the innate immune response, specifically TLR2 activation, against MRSA infection. Here, we evaluate the protective effect and the mechanism of MRSA murine pneumonia after pretreatment with Pam3CSK4, a TLR2 agonist. We found that the MRSA-pneumonia mouse model, pretreated with Pam3CSK4, had reduced bacteria and mortality in comparison to control mice. As well, lower protein and mRNA levels of TNF-α, IL-1β and IL-6 were observed in lungs and bronchus of the Pam3CSK4 pretreatment group. Conversely, expression of anti-inflammatory cytokine IL-10, but not TGF-β, increased in Pam3CSK4-pretreated mice. Our additional studies showed that CXCL-2 and CXCL1, which are necessary for neutrophil recruitment, were less evident in the Pam3CSK4-pretreated group compared to control group, whereas the expression of Fcγ receptors (FcγⅠ/Ⅲ) and complement receptors (CR1/3) increased in murine lungs. Furthermore, we found that increased survival and improved bacterial clearance were not a result of higher levels of neutrophil infiltration, but rather a result of enhanced phagocytosis and bactericidal activity of neutrophils in vitro and in vivo as well as increased robust oxidative activity and release of lactoferrin. Our cumulative findings suggest that Pam3CSK4 could be a novel immunotherapeutic candidate against MRSA pneumonia. PMID:26974438

  6. Copper Complexation Screen Reveals Compounds with Potent Antibiotic Properties against Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Haeili, Mehri; Moore, Casey; Davis, Christopher J. C.; Cochran, James B.; Shah, Santosh; Shrestha, Tej B.; Zhang, Yaofang; Bossmann, Stefan H.; Benjamin, William H.

    2014-01-01

    Macrophages take advantage of the antibacterial properties of copper ions in the killing of bacterial intruders. However, despite the importance of copper for innate immune functions, coordinated efforts to exploit copper ions for therapeutic interventions against bacterial infections are not yet in place. Here we report a novel high-throughput screening platform specifically developed for the discovery and characterization of compounds with copper-dependent antibacterial properties toward methicillin-resistant Staphylococcus aureus (MRSA). We detail how one of the identified compounds, glyoxal-bis(N4-methylthiosemicarbazone) (GTSM), exerts its potent strictly copper-dependent antibacterial properties on MRSA. Our data indicate that the activity of the GTSM-copper complex goes beyond the general antibacterial effects of accumulated copper ions and suggest that, in contrast to prevailing opinion, copper complexes can indeed exhibit species- and target-specific activities. Based on experimental evidence, we propose that copper ions impose structural changes upon binding to the otherwise inactive GTSM ligand and transfer antibacterial properties to the chelate. In turn, GTSM determines target specificity and utilizes a redox-sensitive release mechanism through which copper ions are deployed at or in close proximity to a putative target. According to our proof-of-concept screen, copper activation is not a rare event and even extends to already established drugs. Thus, copper-activated compounds could define a novel class of anti-MRSA agents that amplify copper-dependent innate immune functions of the host. To this end, we provide a blueprint for a high-throughput drug screening campaign which considers the antibacterial properties of copper ions at the host-pathogen interface. PMID:24752262

  7. Prevalence and Genetic Diversity of Livestock-Associated Methicillin-Resistant Staphylococcus aureus on Belgian Pork.

    PubMed

    Verhegghe, Marijke; Crombé, Florence; Luyckx, Kaat; Haesebrouck, Freddy; Butaye, Patrick; Herman, Lieve; Heyndrickx, Marc; Rasschaert, Geertrui

    2016-01-01

    Since the first description of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA), a high prevalence was observed in pigs. At present, questions remain about the transmission of LA-MRSA to the general human population through pork. The objectives of the present study were to determine the prevalence of LA-MRSA in Belgian pork and to determine the role of the pork production chain and butcheries in transmission of LA-MRSA to the human population. Pig meat samples (chops, bacon, minced pork, ribs, forelimbs, and ears; n = 137) originating from four butcheries (A through D) were spread plated on ChromID MRSA plates both before and after overnight enrichment culture. Suspect colonies were confirmed using a MRSA-specific triplex PCR assay and a CC398-specific PCR assay. The isolates (n = 147) were further characterized by SCCmec typing, multiple-locus variable number tandem repeat analysis, and antimicrobial susceptibility testing, a selection of isolates were subjected to pulsed-field gel electrophoresis and spa typing. Direct plating revealed a MRSA prevalence of 8%. After enrichment, MRSA was isolated from 98 (72%) of 137 samples of which the majority were from rib, ear, and forelimb. The majority (97%) of obtained isolates belonged to CC398, the main LA-MRSA type. A high level of genetic diversity was noted among the isolates from one butchery. Thirty antimicrobial susceptibility profiles were found; 13 and 9% of the isolates had Cip-Tet-Tri and Gen-Kan-Tet-Tob-Tri profiles, respectively. These results indicate the importance of enrichment for MRSA detection of pork. The observed genetic diversity of the isolates indicated that the pork production chain can be considered a source of multiple MRSA types that could be transmitted to the human population through cross-contaminated meat.

  8. Topical Bactroban (mupirocin): efficacy in treating burn wounds infected with methicillin-resistant staphylococci.

    PubMed

    Strock, L L; Lee, M M; Rutan, R L; Desai, M H; Robson, M C; Herndon, D N; Heggers, J P

    1990-01-01

    Bacterial antimicrobial susceptibility predictors such as the minimal inhibitory concentration (MIC) assay and Nathans Agar Well Diffusion (NAWD) assay provide essential information relevant to the therapeutic approach in burn-wound sepsis. The susceptibilities of 68 gram-positive burn-wound isolates were tested against topical Bactroban (mupirocin) (Beecham Laboratories, Bristol, Tenn.) and compared with other topical antimicrobials such as mafenide acetate, silver sulfadiazine, and bacitracin/neomycin/polymyxin (BNP). Topical susceptibility data were obtained with a modification of NAWD assay. Bactroban's antimicrobial activity was greater than that of mafenide acetate (100% vs 97%), and significantly greater than that of silver sulfadiazine and that of BNP (p less than 0.001). Of the 68 isolates that were susceptible to Bactroban, 51 were predominately methicillin-resistant staphylococci (MRSA). Bactroban showed in vitro activity against 71% of the 85 gram-negative isolates tested. Mafenide acetate showed activity against 89% of these isolates, a significant difference compared with Bactroban (p less than 0.02). In general, no significant difference was found between the activities of Bactroban and silver sulfadiazine against the gram-negative isolates. The activities of mafenide acetate and silver sulfadiazine against isolates of Pseudomonas aeruginosa were significantly greater than that of Bactroban (p less than 0.05). Bactroban may be used in the treatment of documented staphylococcal burn-wound infections. On the basis of the in vitro data, 13 patients with MRSA burn-wound infections susceptible to Bactroban were evaluated. Quantitative wound biopsies were employed to determine the efficacy of this therapeutic approach. The outcome of these infections was correctly predicted by the NAWD assay in 92.3% of the patients treated (p less than 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Direct Repeat Unit (dru) Typing of Methicillin-Resistant Staphylococcus pseudintermedius from Dogs and Cats.

    PubMed

    Kadlec, Kristina; Schwarz, Stefan; Goering, Richard V; Weese, J Scott

    2015-12-01

    Methicillin-resistant Staphylococcus pseudintermedius (MRSP) has emerged in a remarkable manner as an important problem in dogs and cats. However, limited molecular epidemiological information is available. The aims of this study were to apply direct repeat unit (dru) typing in a large collection of well-characterized MRSP isolates and to use dru typing to analyze a collection of previously uncharacterized MRSP isolates. Two collections of MRSP isolates from dogs and cats were included in this study. The first collection comprised 115 well-characterized MRSP isolates from North America and Europe. The data for these isolates included multilocus sequence typing (MLST) and staphylococcal protein A gene (spa) typing results as well as SmaI macrorestriction patterns after pulsed-field gel electrophoresis (PFGE). The second collection was a convenience sample of 360 isolates from North America. The dru region was amplified by PCR, sequenced, and analyzed. For the first collection, the discriminatory indices of the typing methods were calculated. All isolates were successfully dru typed. The discriminatory power for dru typing (D = 0.423) was comparable to that of spa typing (D = 0.445) and of MLST (D = 0.417) in the first collection. Occasionally, dru typing was able to further discriminate between isolates that shared the same spa type. Among all 475 isolates, 26 different dru types were identified, with 2 predominant types (dt9a and dt11a) among 349 (73.4%) isolates. The results of this study underline that dru typing is a useful tool for MRSP typing, being an objective, standardized, sequence-based method that is relatively cost-efficient and easy to perform.

  10. Molecular epidemiology of Methicillin-resistant Staphylococcus aureus in Africa: a systematic review

    PubMed Central

    Abdulgader, Shima M.; Shittu, Adebayo O.; Nicol, Mark P.; Kaba, Mamadou

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections are a serious global problem, with considerable impact on patients and substantial health care costs. This systematic review provides an overview on the clonal diversity of MRSA, as well as the prevalence of Panton-Valentine leukocidin (PVL)-positive MRSA in Africa. A search on the molecular characterization of MRSA in Africa was conducted by two authors using predefined terms. We screened for articles published in English and French through to October 2014 from five electronic databases. A total of 57 eligible studies were identified. Thirty-four reports from 15 countries provided adequate genotyping data. CC5 is the predominant clonal complex in the healthcare setting in Africa. The hospital-associated MRSA ST239/ST241-III [3A] was identified in nine African countries. This clone was also described with SCCmec type IV [2B] in Algeria and Nigeria, and type V [5C] in Niger. In Africa, the European ST80-IV [2B] clone was limited to Algeria, Egypt and Tunisia. The clonal types ST22-IV [2B], ST36-II [2A], and ST612-IV [2B] were only reported in South Africa. No clear distinctions were observed between MRSA responsible for hospital and community infections. The community clones ST8-IV [2B] and ST88-IV [2B] were reported both in the hospital and community settings in Angola, Cameroon, Gabon, Ghana, Madagascar, Nigeria, and São Tomé and Príncipe. The proportion of PVL-positive MRSA carriage and/or infections ranged from 0.3 to 100% in humans. A number of pandemic clones were identified in Africa. Moreover, some MRSA clones are limited to specific countries or regions. We strongly advocate for more surveillance studies on MRSA in Africa. PMID:25983721

  11. Capsaicin Protects Mice from Community-Associated Methicillin-Resistant Staphylococcus aureus Pneumonia

    PubMed Central

    Xing, Yan; Leng, Bingfeng; Dong, Jing; Li, Hongen; Luo, Mingjing; Zhang, Yu; Dai, Xiaohan; Luo, Yonghuang; Deng, Xuming

    2012-01-01

    Background α-toxin is one of the major virulence factors secreted by most Staphylococcus aureus strains, which played a central role in the pathogenesis of S. aureus pneumonia. The aim of this study was to investigate the impact of capsaicin on the production of α-toxin by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strain USA 300 and to further assess its performance in the treatment of CA-MRSA pneumonia in a mouse model. Methodology/Principal Findings The in vitro effects of capsaicin on α-toxin production by S. aureus USA 300 were determined using hemolysis, western blot, and real-time RT-PCR assays. The influence of capsaicin on the α-toxin-mediated injury of human alveolar epithelial cells was determined using viability and cytotoxicity assays. Mice were infected intranasally with S. aureus USA300; the in vivo protective effects of capsaicin against S. aureus pneumonia were assessed by monitoring the mortality, histopathological changes and cytokine levels. Low concentrations of capsaicin substantially decreased the production of α-toxin by S. aureus USA 300 without affecting the bacterial viability. The addition of capsaicin prevented α-toxin-mediated human alveolar cell (A549) injury in co-culture with S. aureus. Furthermore, the in vivo experiments indicated that capsaicin protected mice from CA-MRSA pneumonia caused by strain USA 300. Conclusions/Significance Capsaicin inhibits the production of α-toxin by CA-MRSA strain USA 300 in vitro and protects mice from CA-MRSA pneumonia in vivo. However, the results need further confirmation with other CA-MRSA lineages. This study supports the views of anti-virulence as a new antibacterial approach for chemotherapy. PMID:22427935

  12. Reduction of Methicillin-Resistant Staphylococcus aureus Infection among Veterans in Atlanta

    PubMed Central

    Stenehjem, Edward; Stafford, Cortney; Rimland, David

    2013-01-01

    OBJECTIVE Describe local changes in the incidence of community-onset and hospital-onset methicillin-resistant Staphylococcus aureus (MRSA) infection and evaluate the impact of MRSA active surveillance on hospital-onset infection. DESIGN Observational study using prospectively collected data. SETTING Atlanta Veterans Affairs Medical Center (AVAMC). PATIENTS All patients seen at the AVAMC over an 8-year period with clinically and microbiologically proven MRSA infection. METHODS All clinical cultures positive for MRSA were prospectively identified, and corresponding clinical data were reviewed. MRSA infections were classified into standard clinical and epidemiologic categories. The Veterans Health Administration implemented the MRSA directive in October 2007, which required active surveillance cultures in acute care settings. RESULTS The incidence of community-onset MRSA infection peaked in 2007 at 5.45 MRSA infections per 1,000 veterans and decreased to 3.14 infections per 1,000 veterans in 2011 (P ≤ .001 for trend). Clinical and epidemiologic categories of MRSA infections did not change throughout the study period. The prevalence of nasal MRSA colonization among veterans admitted to AVAMC decreased from 15.8% in 2007 to 11.2% in 2011 (P < .001 for trend). The rate of intensive care unit (ICU)–related hospital-onset MRSA infection decreased from October 2005 through March 2007, before the MRSA directive. Rates of ICU-related hospital-onset MRSA infection remained stable after the implementation of active surveillance cultures. No change was observed in rates of non-ICU-related hospital-onset MRSA infection. CONCLUSIONS Our study of the AVAMC population over an 8-year period shows a consistent trend of reduction in the incidence of MRSA infection in both the community and healthcare settings. The etiology of this reduction is most likely multifactorial. PMID:23221194

  13. When are the hands of healthcare workers positive for methicillin-resistant Staphylococcus aureus?

    PubMed

    Creamer, E; Dorrian, S; Dolan, A; Sherlock, O; Fitzgerald-Hughes, D; Thomas, T; Walsh, J; Shore, A; Sullivan, D; Kinnevey, P; Rossney, A S; Cunney, R; Coleman, D; Humphreys, H

    2010-06-01

    Hand hygiene is a key component in reducing infection. There are few reports on the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) on healthcare workers' (HCWs') hands. The aim of this study was to establish whether HCWs' fingertips were contaminated with MRSA in a clinical hospital setting. The study was conducted in an acute tertiary referral hospital on four MRSA wards that were part of a larger research study on MRSA epidemiology and four other wards not included in the study. The fingertips from all categories of 523 HCWs were sampled on 822 occasions by the imprinting of fingertips on MRSA chromogenic agar plates. The type of hand hygiene agent used, if any, and the immediate prior activity of the HCW were recorded. Overall, 38/822 (5%) fingertips from 523 HCWs were MRSA-positive; 12/194 (6%) after clinical contact, 10/138 (10%) after contact with the patient's environment and 15/346 (4%) after no specific contact. MRSA was recovered on 2/61 (3%) occasions after use of alcohol hand rub, 2/35 (6%) after 4% chlorhexidine detergent, 7/210 (3%) hand washing with soap and water, and 27/493 (5%) when no hand hygiene had been performed. MRSA was recovered from HCWs on seven of the eight wards. MRSA was more frequently present on fingertips on the four non-study wards vs the four MRSA study wards [18/250 (7%), 3/201 (1%), respectively; P

  14. Environmental Methicillin-Resistant Staphylococcus aureus in a Veterinary Teaching Hospital During a Nonoutbreak Period

    PubMed Central

    Johnson, Amanda; Nava-Hoet, Rocio C.; Bateman, Shane; Hillier, Andrew; Dyce, John; Gebreyes, Wondwossen A.; Wittum, Thomas E.

    2011-01-01

    Abstract Concurrent to reports of zoonotic and nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) in veterinary settings, recent evidence indicates that the environment in veterinary hospitals may be a potential source of MRSA. The present report is a cross-sectional study to determine the prevalence of MRSA on specific human and animal contact surfaces at a large veterinary hospital during a nonoutbreak period. A total of 156 samples were collected using Swiffers® or premoistened swabs from the small animal, equine, and food animal sections. MRSA was isolated and identified by pre-enrichment culture and standard microbiology procedures, including growth on Mueller-Hinton agar supplemented with NaCl and oxacillin, and by detection of the mecA gene. Staphylococcal chromosome cassette mec (SCCmec) typing and pulsed-field gel electrophoresis profile were also determined. MRSA was detected in 12% (19/157) of the hospital environments sampled. The prevalence of MRSA in the small animal, equine, and food animal areas were 16%, 4%, and 0%, respectively. Sixteen of the MRSA isolates from the small animal section were classified as USA100, SCCmec type II, two of which had pulsed-field gel electrophoresis pattern that does not conform to any known type. The one isolate obtained from the equine section was classified as USA500, SCCmec type IV. The molecular epidemiological analysis revealed a very diverse population of MRSA isolates circulating in the hospital; however, in some instances, multiple locations/surfaces, not directly associated, had the same MRSA clone. No significant difference was observed between animal and human contact surfaces in regard to prevalence and type of isolates. Surfaces touched by multiple people (doors) and patients (carts) were frequently contaminated with MRSA. The results from this study indicate that MRSA is present in the environment even during nonoutbreak periods. This study also identified specific surfaces in

  15. Differentiation of clonal complex 59 community-associated methicillin-resistant Staphylococcus aureus in Western Australia.

    PubMed

    Coombs, Geoffrey W; Monecke, Stefan; Ehricht, Ralf; Slickers, Peter; Pearson, Julie C; Tan, Hui-Leen; Christiansen, Keryn J; O'Brien, Frances G

    2010-05-01

    Clonal complex 59 (CC59) community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains were characterized using pulsed-field gel electrophoresis, spa typing, multilocus sequence typing, diagnostic DNA microarrays, and PCRs targeting staphylococcal cassette chromosome mec (SCCmec) elements and Panton-Valentine leukocidin (PVL). Six distinct groups within CC59 were characterized. At least seven different variants of SCCmec elements were identified (IVa [2B], IVb [2B], IVd [2B], IV variant [2B], IVa [2B&5], V variant [5C2], and V [5C2&5]). (The structural type is indicated by a Roman numeral, with a lowercase letter indicating the subtype, and the ccr complex and the mec complex are indicated by an Arabic numeral and an uppercase letter, respectively. Where there is an extra ccr element, this is indicated by "&" and an Arabic numeral designating the ccr type.) The first group is similar to the American sequence type 59 (ST59) MRSA-IV CA-MRSA strain USA1000. The second group includes a PVL-negative ST87 strain with an SCCmec element of subtype IVb (2B). The third group comprises PVL-variable ST59 MRSA-IV strains harboring multiple SCCmec IV subtypes. PVL-negative ST59 MRSA strains with multiple or composite SCCmec elements (IVa [2B&5]) form the fourth group. Group 5 corresponds to the internationally known "Taiwan clone," a PVL-positive strain with a variant SCCmec element (V [5C2&5]). This strain proved to be the most common CC59 MRSA strain isolated in Western Australia. Finally, group 6 encompasses the ST59 MRSA-V variant (5C2). The differentiation of CC59 into groups and strains indicates a rapid evolution and spread of SCCmec elements. Observed differences between groups of strains as well as intrastrain variability within a group facilitate the tracing of their spread. PMID:20211891

  16. Environmental methicillin-resistant Staphylococcus aureus in a veterinary teaching hospital during a nonoutbreak period.

    PubMed

    Hoet, Armando E; Johnson, Amanda; Nava-Hoet, Rocio C; Bateman, Shane; Hillier, Andrew; Dyce, John; Gebreyes, Wondwossen A; Wittum, Thomas E

    2011-06-01

    Concurrent to reports of zoonotic and nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) in veterinary settings, recent evidence indicates that the environment in veterinary hospitals may be a potential source of MRSA. The present report is a cross-sectional study to determine the prevalence of MRSA on specific human and animal contact surfaces at a large veterinary hospital during a nonoutbreak period. A total of 156 samples were collected using Swiffers(®) or premoistened swabs from the small animal, equine, and food animal sections. MRSA was isolated and identified by pre-enrichment culture and standard microbiology procedures, including growth on Mueller-Hinton agar supplemented with NaCl and oxacillin, and by detection of the mecA gene. Staphylococcal chromosome cassette mec (SCCmec) typing and pulsed-field gel electrophoresis profile were also determined. MRSA was detected in 12% (19/157) of the hospital environments sampled. The prevalence of MRSA in the small animal, equine, and food animal areas were 16%, 4%, and 0%, respectively. Sixteen of the MRSA isolates from the small animal section were classified as USA100, SCCmec type II, two of which had pulsed-field gel electrophoresis pattern that does not conform to any known type. The one isolate obtained from the equine section was classified as USA500, SCCmec type IV. The molecular epidemiological analysis revealed a very diverse population of MRSA isolates circulating in the hospital; however, in some instances, multiple locations/surfaces, not directly associated, had the same MRSA clone. No significant difference was observed between animal and human contact surfaces in regard to prevalence and type of isolates. Surfaces touched by multiple people (doors) and patients (carts) were frequently contaminated with MRSA. The results from this study indicate that MRSA is present in the environment even during nonoutbreak periods. This study also identified specific surfaces in a

  17. Methicillin-resistant Staphylococcus aureus multiple sites surveillance: a systemic review of the literature

    PubMed Central

    Chipolombwe, John; Török, Mili Estee; Mbelle, Nontombi; Nyasulu, Peter

    2016-01-01

    Purpose The objective of this study was to evaluate the optimal number of sampling sites for detection of methicillin-resistant Staphylococcus aureus (MRSA) colonization. Methods We performed a Medline search from January 1966 to February 2014 for articles that reported the prevalence of MRSA at different body sites. Studies were characterized by study design, country and period of the study, number of patients and/or isolates of MRSA, specimen type, sites of MRSA isolation, study population sampled, diagnostic testing method, and percentage of the MRSA isolates at each site in relation to the total number of sites. Results We reviewed 3,211 abstracts and 177 manuscripts, of which 17 met the criteria for analysis (n=52,642 patients). MRSA colonization prevalence varied from 8% to 99% at different body sites. The nasal cavity as a single site had MRSA detection sensitivity of 68% (34%–91%). The throat and nares gave the highest detection rates as single sites. A combination of two swabs improved MRSA detection rates with the best combination being groin/throat (89.6%; 62.5%–100%). A combination of three swab sites improved MRSA detection rate to 94.2% (81%–100%) with the best combination being groin/nose/throat. Certain combinations were associated with low detection rates. MRSA detection rates also varied with different culture methods. Conclusion A combination of three swabs from different body sites resulted in the highest detection rate for MRSA colonization. The use of three swab sites would likely improve the recognition and treatment of MRSA colonization, which may in turn reduce infection and transmission of MRSA to other patients. PMID:26929653

  18. Methicillin-Resistant Staphylococcus aureus Infections in Human Immunodeficiency Virus-Infected Children and Adolescents

    PubMed Central

    Siberry, George K.; Frederick, Toni; Emmanuel, Patricia; Paul, Mary E.; Bohannon, Beverly; Wheeling, Travis; Barton, Theresa; Rathore, Mobeen H.; Dominguez, Kenneth L.

    2012-01-01

    Background. Methicillin-resistant Staphylococcus aureus (MRSA) infection incidence has increased in healthy US children. Our objective was to evaluate MRSA incidence and correlates in HIV-infected youth. Methods. The CDC-sponsored LEGACY study is a US multicenter chart abstraction study of HIV-infected youth. We identified MRSA infections among participants with ≥1 visit during 2006. We used bivariate and multivariable analyses to compare sociodemographic and HIV clinical factors between MRSA cases and noncases. Results. Fourteen MRSA infections (1 invasive, 12 soft tissue, 1 indeterminate) occurred among 1,813 subjects (11.1 infections/1,000 patient-years (PY), 95% CI: 11.06–11.14). Most (86%) isolates were clindamycin susceptible. Compared with noncases, MRSA cases were more likely older (17 versus 14 years), black (100% versus 69%), behaviorally HIV infected (43% versus 17%), and in Maryland (43% versus 7%) and had viral loads (VL) >1000 copies/mL (86% versus 51%) and lower mean CD4% (18% versus 27%) (all P < 0.05). In multivariate analysis, independent risk factors were Maryland care site (adjusted odds ratio (aOR) = 9.0), VL >1000 copies/mL (aOR = 5.9), and black race (aOR undefined). Conclusions. MRSA occurred at a rate of 11.1 infections/1,000 PY in HIV-infected youth but invasive disease was uncommon. Geographic location, black race, and increased VL, but not immunosuppression, were independently associated with MRSA risk. PMID:23008761

  19. Direct Repeat Unit (dru) Typing of Methicillin-Resistant Staphylococcus pseudintermedius from Dogs and Cats

    PubMed Central

    Schwarz, Stefan; Goering, Richard V.; Weese, J. Scott

    2015-01-01

    Methicillin-resistant Staph