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Sample records for reduce methicillin-resistant staphylococcus

  1. Dalbavancin reduces biofilms of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE).

    PubMed

    Knafl, D; Tobudic, S; Cheng, S C; Bellamy, D R; Thalhammer, F

    2017-04-01

    Activity of dalbavancin against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) in biofilm was investigated and the microbicidal biofilm concentrations (MBC) were determined. Biofilms obtained from ten MRSA and ten MRSE bloodstream isolates, collected from patients in the General Hospital of Vienna between 2012 and 2015, were incubated with dalbavancin in trypticase soy broth (TSB) in serial dilution from 0.0625 mg/l to 256 mg/l using a microtiter plate biofilm model. The plates were incubated for 24 h at 37 ° C and 50% humidity. Biofilms were fixed with 2.5% glutaraldehyde and stained with crystal violet. Subsequently the optical density (OD620) was used to measure the MBC, defined as the concentration of dalbavancin leading to a 50% reduction of biofilm. MBC for MRSA was 1 mg/l-4 mg/l (minimal inhibitory concentrations (MIC) 0.0312 mg/l-0.064 mg/l). MBC for MRSE was 2 mg/l-16 mg/l (MIC 0.023 mg/l-0.0625 mg/l). Dalbavancin successfully reduced MRSA and MRSE in biofilms, and therefore provides a promising option for the treatment of biofilm-associated infections.

  2. High level methicillin resistance correlates with reduced Staphylococcus aureus endothelial cell damage.

    PubMed

    Seidl, Kati; Leemann, Michèle; Palheiros Marques, Miguel; Rachmühl, Carole; Leimer, Nadja; Andreoni, Federica; Achermann, Yvonne; Zinkernagel, Annelies S

    2017-01-01

    There has been controversy about the intrinsic virulence of methicillin-resistant Staphylococcus aureus (MRSA) as compared to methicillin-susceptible S. aureus (MSSA). To address this discrepancy, the intrinsic virulence of 42 MRSA and 40 MSSA clinical isolates was assessed by testing endothelial cell (EC) damage, a surrogate marker for virulence in blood stream infections. Since these clinical isolates represent a heterogeneous group, well characterized S. aureus laboratory strains with SCCmec loss- and gain-of-function mutations were used in addition. The clinical MRSA isolates carrying typical hospital acquired SCCmec types (I, II or III) induced significantly less damage (47.8%) as compared to isolates with other SCCmec types (62.3%, p=0.03) and MSSA isolates (64.2%, p<0.01). There was a strong inverse correlation between high-level oxacillin resistance and low EC damage induction (R(2)=0.4464, p<0.001). High-level oxacillin resistant strains (MIC >32μ/ml) grew significantly slower as compared to isolates with low-level resistance (p=0.047). The level of EC damage positively correlated with α- and δ-toxin production (p<0.0001 and p<0.05, respectively) but not with β-toxin production. Invasive MRSA isolates (n=21, 56.3%) were significantly less cytotoxic as compared to invasive MSSA isolates (n=20, 68.0%, p<0.05). There was no difference between EC damage induced by superficial versus invasive isolates in either MRSA or MSSA strains. Our data suggest that the intrinsic virulence of MRSA is similar or even reduced as compared to MSSA strains but is linked to the level of methicillin resistance.

  3. Methicillin Resistance Reduces the Virulence of Healthcare-Associated Methicillin-Resistant Staphylococcus aureus by Interfering With the agr Quorum Sensing System

    PubMed Central

    Rudkin, Justine K.; Edwards, Andrew M.; Bowden, Maria G.; Brown, Eric L.; Pozzi, Clarissa; Waters, Elaine M.; Chan, Weng C.; Williams, Paul; O’Gara, James P.

    2012-01-01

    The difficulty in successfully treating infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has led to them being referred to as highly virulent or pathogenic. In our study of one of the major healthcare-associated MRSA (HA-MRSA) clones, we show that expression of the gene responsible for conferring methicillin resistance (mecA) is also directly responsible for reducing the ability of HA-MRSA to secrete cytolytic toxins. We show that resistance to methicillin induces changes in the cell wall, which affects the bacteria's agr quorum sensing system. This leads to reduced toxin expression and, as a consequence, reduced virulence in a murine model of sepsis. This diminished capacity to cause infection may explain the inability of HA-MRSA to move into the community and help us understand the recent emergence of community-associated MRSA (CA-MRSA). CA-MRSA typically express less penicillin-binding protein 2a (encoded by mecA), allowing them to maintain full virulence and succeed in the community environment. PMID:22301683

  4. Methicillin-resistant Staphylococcus aureus (MRSA)

    MedlinePlus

    Methicillin-resistant Staphylococcus aureus; Hospital-acquired MRSA (HA-MRSA); Staph - MRSA; Staphylococcal - MRSA ... Que YA, Moreillon P. Staphylococcus aureus (including ... MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice ...

  5. Can 'search and destroy' reduce nosocomial methicillin-resistant Staphylococcus aureus in an Irish hospital?

    PubMed

    Higgins, A; Lynch, M; Gethin, G

    2010-06-01

    In Ireland, the Department of Health and Children recommends admission screening of patients at increased risk of methicillin-resistant Staphylococcus aureus (MRSA), isolation of these patients until proven negative, and eradication of any MRSA identified. These actions form the basis of a programme called 'search and destroy' that has successfully reduced MRSA in Scandinavia. There is, however, very little information published on the use of search and destroy in Ireland. This study was carried out using a quantitative, quasi-experimental design in the form of an interventional cohort study. The effect of reducing the turnaround time for MRSA results (2007) and the introduction of pre-emptive isolation (2008) was examined in a hospital with an established admission screening programme for MRSA. Rates of MRSA infection and colonisation were monitored post-intervention and compared to baseline rates prior to the intervention (2005-2006). Rates of hospital-acquired (nosocomial) MRSA infections and colonisation fell in both 2007 and 2008. However, due to the quasi-experimental design of the study and the low endemic level of MRSA in the hospital, a causal link could not be established. (c) 2009 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

  6. Outbreak of Methicillin-Resistant Staphylococcus aureus with Reduced Susceptibility to Glycopeptides in a Parisian Hospital

    PubMed Central

    Guerin, François; Buu-Hoï, Annie; Mainardi, Jean-Luc; Kac, Guillaume; Colardelle, Nathalie; Vaupré, Sabine; Gutmann, Laurent; Podglajen, Isabelle

    2000-01-01

    Epidemiological relationships were investigated between 40 methicillin-resistant Staphylococcus aureus (MRSA) strains with decreased glycopeptide susceptibility isolated from November 1998 to March 1999 from 39 patients (17 infected and 22 colonized patients) in nine wards of the Broussais Hospital, Paris, France. Reduced glycopeptide susceptibility was readily detected on brain heart infusion (BHI) agar containing 6 μg of teicoplanin per ml and on gradient plates, but not by the standard disk diffusion method. The MICs of vancomycin and teicoplanin, determined on BHI agar, were 4 and 8 to 32 μg/ml, respectively (standard antibiotic dilution), and 4 to 8 and 8 to 32 μg/ml, respectively (E-test). All strains were resistant to macrolides, aminoglycosides, tetracycline, rifampin, sulfonamides, and pefloxacin, showed reduced susceptibility to fusidic acid and fosfomycin, and were susceptible to trimethoprim and chloramphenicol. Pulsed-field gel electrophoresis and lysotyping revealed that a multidrug-resistant MRSA clone with decreased susceptibility to glycopeptides has been discretely endemic since at least 1996 in our institution, where it was responsible for an outbreak in November and December 1998. PMID:10921964

  7. A statewide collaborative to reduce methicillin-resistant Staphylococcus aureus bacteremias in New Mexico.

    PubMed

    Kellie, Susan M; Timmins, Anne; Brown, Carlene

    2011-04-01

    Infection control guidelines recommend multiple concurrent interventions to reduce methicillin-resistant Staphylococcus aureus (MRSA) infections. A quasi-experimental study was conducted to investigate the effect of an infection control collaborative conducted from July 1, 2008, through June 30, 2009, to decrease the rate of hospital-onset bacteremias by 40%. An MRSA curriculum was developed and delivered during three learning sessions. Guidelines, key literature, policies, and educational tools were disseminated. Teams were surveyed at the end of the collaborative and again 18 months later. Teams were recruited from 12 acute care hospitals and 1 long-term acute care hospital, with capacities ranging from 22 to 623 licensed beds. Hospital intervention teams reported 44 hospital-onset, 18 health care-associated, and 122 community-onset MRSA bacteremias in the baseline year, yielding a hospital-onset rate of 0.79 per 10,000 patient-days. By the second six months of the intervention, this rate fell to 0.41, representing an aggregate 48% decline--but a nonsignificant result. Rates of health care-associated and community-onset bacteremias were unchanged. At baseline, 4 hospitals routinely performed active surveillance testing (AST) on 241 beds, which increased to 7 hospitals and 369 beds by July 2009. A follow-up survey completed by 11 hospitals indicated that barriers were similar for large and small facilities. A final survey performed 18 months postcollaborative indicated that 2 additional hospitals had initiated AST, 5 had expanded the use of AST, and only 1 had discontinued AST. A collaborative model was successfully used to engage a diverse group of hospitals in a rural state to produce measurable improvement and sustained changes in processes of care.

  8. Chlorhexidine gluconate reduces transmission of methicillin-resistant Staphylococcus aureus USA300 among Marine recruits.

    PubMed

    Whitman, Timothy J; Schlett, Carey D; Grandits, Greg A; Millar, Eugene V; Mende, Katrin; Hospenthal, Duane R; Murray, Patrick R; Tribble, David R

    2012-08-01

    Methicillin-resistant Staphylococcus aureus (MRSA) pulsed-field type (PFT) USA300 causes skin and soft tissue infections in military recruits and invasive disease in hospitals. Chlorhexidine gluconate (CHG) is used to reduce MRSA colonization and infection. The impact of CHG on the molecular epidemiology of MRSA is not known. To evaluate the impact of 2% CHG-impregnated cloths on the molecular epidemiology of MRSA colonization. Cluster-randomized, double-blind, controlled trial. Marine Officer Candidate School, Quantico, Virginia, in 2007. Military recruits. Thrice-weekly application of CHG-impregnated or control (Comfort Bath; Sage) cloths over the entire body. Baseline and serial (every 2 weeks) nasal and/or axillary swab samples were assessed for MRSA colonization. Molecular analysis was performed with pulsed-field gel electrophoresis. During training, 77 subjects (4.9%) acquired MRSA, 26 (3.3%) in the CHG group and 51 (6.5%) in the control group (P=.004). When analyzed for PFT, 24 subjects (3.1%) in the control group but only 6 subjects (0.8%) in the CHG group (P=.001) had USA300. Of the 167 colonizing isolates recovered from 77 subjects, 99 were recovered from the control group, including USA300 (40.4%), USA800 (38.4%), USA1000 (12.1%), and USA100 (6.1%), and 68 were recovered from the CHG group, including USA800 (51.5%), USA100 (23.5%), and USA300 (13.2%). CHG decreased the transmission of MRSA--more specifically, USA300--among military recruits. In addition, USA300 and USA800 outcompeted other MRSA PFTs at incident colonization. Future studies should evaluate the broad-based use of CHG to decrease transmission of USA300 in hospital settings.

  9. Reduced susceptibility to vancomycin and biofilm formation in methicillin-resistant Staphylococcus epidermidis isolated from blood cultures

    PubMed Central

    Pinheiro, Luiza; Brito, Carla Ivo; Pereira, Valéria Cataneli; de Oliveira, Adilson; Camargo, Carlos Henrique; da Cunha, Maria de Lourdes Ribeiro de Souza

    2014-01-01

    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

  10. 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.

  11. Methicillin resistant Staphylococcus aureus in Ethiopia: a meta-analysis.

    PubMed

    Eshetie, Setegn; Tarekegn, Fentahun; Moges, Feleke; Amsalu, Anteneh; Birhan, Wubet; Huruy, Kahsay

    2016-11-21

    The burden of methicillin resistant Staphylococcus aureus is a major public health concern worldwide; however the overall epidemiology of multidrug resistant strains is neither coordinated nor harmonized, particularly in developing countries including Ethiopia. Therefore, the aim of this meta-analysis was to assess the burden of methicillin resistant Staphylococcos aureus and its antibiotic resistance pattern in Ethiopia at large. PubMed, Google Scholar, and lancet databases were searched and a total of 20 studies have been selected for meta-analysis. Six authors have independently extracts data on the prevalence of methicillin resistant Staphylococcus aureus among clinical isolates of Staphylococcus aureus. Statistical analysis was achieved by using Open meta-analyst (version 3.13) and Comprehensive meta-analysis (version 3.3) softwares. The overall prevalence of methicillin resistant Staphylococcus aureus and its antibiotic resistance pattern were pooled by using the forest plot, table and figure with 95% CI. The pooled prevalence of methicillin resistant Staphylococcus aureus was 32.5% (95% CI, 24.1 to 40.9%). Moreover, methicillin resistant Staphylococcus aureus strains were found to be highly resistant to penicillin, ampicillin, erythromycin, and amoxicillin, with a pooled resistance ratio of 99.1, 98.1, 97.2 and 97.1%, respectively. On the other hand, comparably low levels of resistance ratio were noted to vancomycin, 5.3%. The overall burden of methicillin resistant Staphylococcus aureus is considerably high, besides these strains showed extreme resistance to penicillin, ampicillin, erythromycin and amoxicillin. In principle, appropriate use of antibiotics, applying safety precautions are the key to reduce the spread of multidrug resistant strains, methicillin resistant Staphylococcus aureus in particular.

  12. Methicillin resistant Staphylococcus aureus - an overview.

    PubMed

    Haque, N; Bari, M S; Bilkis, L; Haque, N; Haque, S; Sultana, S

    2011-01-01

    Staphylococcus aureus strains those are resistant to methicillin are referred to as Methicillin resistant Staphylococcus aureus. These express mecA gene to produce altered penicillin binding protein. At present Methicillin resistant Staphylococcus aureus has been increasing as a serious nosocomial and community pathogen having the property of multi drug resistant. Humans are the natural reservoir for Staphylococcus aureus and asymptomatic colonization is far more common than infection. Many hospitals of different country of the world including Bangladesh are struggling with increasing number of this versatile pathogen. Early and specific diagnosis is important to ensure a favourable outcome. In this paper we attempted to explore history, prevalence, transmission, risk factors, pathogenicity, laboratory diagnosis, prevention and control of Methicillin resistant Staphylococcus aureus as a critical review to provide some new upgrade regarding this super bug.

  13. Impact of Reduced Vancomycin MIC on Clinical Outcomes of Methicillin-Resistant Staphylococcus aureus Bacteremia

    PubMed Central

    Park, So-Youn; Oh, In-Hwan; Lee, Hee-Joo; Ihm, Chun-Gyoo; Son, Jun Seong

    2013-01-01

    Vancomycin has been a key antibiotic agent for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. However, little is known about the relationship between vancomycin MIC values at the higher end of the susceptibility range and clinical outcomes. The aim of this study was to determine the impact of MRSA bacteremia on clinical outcomes in patients with a vancomycin MIC near the upper limit of the susceptible range. Patients with MRSA bacteremia were divided into a high-vancomycin-MIC group (2 μg/ml) and a low-vancomycin-MIC group (≤1.0 μg/ml). We examined the relationship between MIC, genotype, primary source of bacteremia, and mortality. Ninety-four patients with MRSA bacteremia, including 31 with a high vancomycin MIC and 63 with a low MIC were analyzed. There was no significant difference between the presence of agr dysfunction and SCCmec type between the two groups. A higher vancomycin MIC was not found to be associated with mortality. In contrast, high-risk bloodstream infection sources (hazard ratio [HR], 4.63; 95% confidence interval [CI] = 1.24 to 17.33) and bacterial eradication after treatment (HR, 0.06; 95% CI = 0.02 to 0.17), irrespective of vancomycin MIC, were predictors of all-cause 30-day mortality. Our study suggests that a high-risk source of bacteremia is likely to be associated with unfavorable clinical outcomes, but a high vancomycin MIC in a susceptible range, as well as genotype characteristics, are not associated with mortality. PMID:23979741

  14. Review on methicillin-resistant Staphylococcus pseudintermedius.

    PubMed

    van Duijkeren, Engeline; Catry, Boudewijn; Greko, Christina; Moreno, Miguel A; Pomba, M Constança; Pyörälä, Satu; Ruzauskas, Modestas; Sanders, Pascal; Threlfall, E John; Torren-Edo, Jordi; Törneke, Karolina

    2011-12-01

    Staphylococcus pseudintermedius is an important opportunistic pathogen of companion animals, especially dogs. Since 2006 there has been a significant emergence of methicillin-resistant S. pseudintermedius (MRSP) mainly due to clonal spread. This article reviews research on MRSP with a focus on occurrence, methods used for identification, risk factors for colonization and infection, zoonotic potential and control options. Potential areas for future research are also discussed.

  15. Silver-Containing Hydroxyapatite Coating Reduces Biofilm Formation by Methicillin-Resistant Staphylococcus aureus In Vitro and In Vivo

    PubMed Central

    Miyamoto, Hiroshi; Shobuike, Takeo; Kobatake, Tomoki; Mawatari, Masaaki

    2016-01-01

    Biofilm-producing bacteria are the principal causes of infections associated with orthopaedic implants. We previously reported that silver-containing hydroxyapatite (Ag-HA) coatings exhibit high antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). In the present study, we evaluated the effects of Ag-HA coating of implant surfaces on biofilm formation. Titanium disks (14-mm diameter, 1-mm thickness), one surface of which was coated with HA or 0.5%–3.0% Ag-HA with a thermal spraying technique, were used. In vitro, the disks were inoculated with an MRSA suspension containing 4 × 105 CFU and incubated for 1-2 weeks. In vivo, MRSA-inoculated HA and 3% Ag-HA disks (8.8–10.0 × 108 CFU) were implanted subcutaneously on the back of rats for 1–7 days. All disks were subsequently stained with a biofilm dye and observed under a fluorescence microscope, and biofilm coverage rates (BCRs) were calculated. The BCRs on the Ag-HA coating were significantly lower than those on the HA coating at all time points in vitro (p < 0.05). Similar results were observed in vivo (p < 0.001) without argyria. Ag-HA coating reduced biofilm formation by MRSA in vitro and in vivo; therefore, Ag-HA coating might be effective for reducing implant-associated infections. PMID:28105433

  16. Methicillin-resistant Staphylococcus aureus in obstetrics.

    PubMed

    Sheffield, Jeanne S

    2013-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) remains one of the major multiple antibiotic-resistant bacterial pathogens causing serious community-associated and health care-associated infections. It is now pervasive in the obstetric population associated with skin and soft tissue infections, mastitis, episiotomy, and cesarean wound infections and urinary tract infections. This review addresses the epidemiology, definitions, microbiology, and pathogenesis as well as common clinical presentations. A discussion of the 2011 Infectious Diseases Society of America MRSA treatment guidelines details available antibiotics, invasive and noninvasive MRSA management, and specific factors related to obstetrics. Finally, prevention strategies including decolonization are discussed. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  17. Chlorhexidine and Mupirocin Susceptibility of Methicillin-Resistant Staphylococcus aureus Isolates in the REDUCE-MRSA Trial.

    PubMed

    Hayden, Mary K; Lolans, Karen; Haffenreffer, Katherine; Avery, Taliser R; Kleinman, Ken; Li, Haiying; Kaganov, Rebecca E; Lankiewicz, Julie; Moody, Julia; Septimus, Edward; Weinstein, Robert A; Hickok, Jason; Jernigan, John; Perlin, Jonathan B; Platt, Richard; Huang, Susan S

    2016-11-01

    Whether targeted or universal decolonization strategies for the control of methicillin-resistant Staphylococcus aureus (MRSA) select for resistance to decolonizing agents is unresolved. The REDUCE-MRSA trial (ClinicalTrials registration no. NCT00980980) provided an opportunity to investigate this question. REDUCE-MRSA was a 3-arm, cluster-randomized trial of either screening and isolation without decolonization, targeted decolonization with chlorhexidine and mupirocin, or universal decolonization without screening to prevent MRSA infection in intensive-care unit (ICU) patients. Isolates from the baseline and intervention periods were collected and tested for susceptibility to chlorhexidine gluconate (CHG) by microtiter dilution; mupirocin susceptibility was tested by Etest. The presence of the qacA or qacB gene was determined by PCR and DNA sequence analysis. A total of 3,173 isolates were analyzed; 2 were nonsusceptible to CHG (MICs, 8 μg/ml), and 5/814 (0.6%) carried qacA or qacB At baseline, 7.1% of MRSA isolates expressed low-level mupirocin resistance, and 7.5% expressed high-level mupirocin resistance. In a mixed-effects generalized logistic regression model, the odds of mupirocin resistance among clinical MRSA isolates or MRSA isolates acquired in an ICU in intervention versus baseline periods did not differ across arms, although estimates were imprecise due to small numbers. Reduced susceptibility to chlorhexidine and carriage of qacA or qacB were rare among MRSA isolates in the REDUCE-MRSA trial. The odds of mupirocin resistance were no different in the intervention versus baseline periods across arms, but the confidence limits were broad, and the results should be interpreted with caution. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  18. Antiseptic Body Washes for Reducing the Transmission of Methicillin-Resistant Staphylococcus aureus: A Cluster Crossover Study

    PubMed Central

    Harris, Patrick N. A.; Le, Bich Diep; Tambyah, Paul; Hsu, Li Yang; Pada, Surinder; Archuleta, Sophia; Salmon, Sharon; Mukhopadhyay, Amartya; Dillon, Jasmine; Ware, Robert; Fisher, Dale A.

    2015-01-01

    Background. Limiting the spread of methicillin-resistant Staphylococcus aureus (MRSA) within healthcare facilities where the organism is highly endemic is a challenge. The use of topical antiseptic agents may help interrupt the transmission of MRSA and reduce the risk of clinical infection. Octenidine dihydrochloride is a topical antiseptic that exhibits in vitro efficacy against a wide variety of bacteria, including S aureus. Methods. We conducted a prospective cluster crossover study to compare the use of daily octenidine body washes with soap and water in patients identified by active surveillance cultures to be MRSA-colonized, to prevent the acquisition of MRSA in patients with negative screening swabs. Five adult medical and surgical wards and 2 intensive care units were selected. The study involved an initial 6-month phase using octenidine or soap washes followed by a crossover in each ward to the alternative product. The primary and secondary outcomes were the rates of new MRSA acquisitions and MRSA clinical infections, respectively. Results. A total of 10 936 patients admitted for ≥48 hours was included in the analysis. There was a small reduction in MRSA acquisition in the intervention group compared with controls (3.0% vs 3.3%), but this reduction was not significant (odds ratio, 0.89; 95% confidence interval, .72–1.11; P = .31). There were also no significant differences in clinical MRSA infection or incidence of MRSA bacteremia. Conclusions. This study suggests that the targeted use of routine antiseptic washes may not in itself be adequate to reduce the transmission of MRSA in an endemic hospital setting. PMID:26125031

  19. Antiseptic Body Washes for Reducing the Transmission of Methicillin-Resistant Staphylococcus aureus: A Cluster Crossover Study.

    PubMed

    Harris, Patrick N A; Le, Bich Diep; Tambyah, Paul; Hsu, Li Yang; Pada, Surinder; Archuleta, Sophia; Salmon, Sharon; Mukhopadhyay, Amartya; Dillon, Jasmine; Ware, Robert; Fisher, Dale A

    2015-04-01

    Background.  Limiting the spread of methicillin-resistant Staphylococcus aureus (MRSA) within healthcare facilities where the organism is highly endemic is a challenge. The use of topical antiseptic agents may help interrupt the transmission of MRSA and reduce the risk of clinical infection. Octenidine dihydrochloride is a topical antiseptic that exhibits in vitro efficacy against a wide variety of bacteria, including S aureus. Methods.  We conducted a prospective cluster crossover study to compare the use of daily octenidine body washes with soap and water in patients identified by active surveillance cultures to be MRSA-colonized, to prevent the acquisition of MRSA in patients with negative screening swabs. Five adult medical and surgical wards and 2 intensive care units were selected. The study involved an initial 6-month phase using octenidine or soap washes followed by a crossover in each ward to the alternative product. The primary and secondary outcomes were the rates of new MRSA acquisitions and MRSA clinical infections, respectively. Results.  A total of 10 936 patients admitted for ≥48 hours was included in the analysis. There was a small reduction in MRSA acquisition in the intervention group compared with controls (3.0% vs 3.3%), but this reduction was not significant (odds ratio, 0.89; 95% confidence interval, .72-1.11; P = .31). There were also no significant differences in clinical MRSA infection or incidence of MRSA bacteremia. Conclusions.  This study suggests that the targeted use of routine antiseptic washes may not in itself be adequate to reduce the transmission of MRSA in an endemic hospital setting.

  20. Methicillin-resistant Staphylococcus aureus: the superbug.

    PubMed

    Ippolito, Giuseppe; Leone, Sebastiano; Lauria, Francesco N; Nicastri, Emanuele; Wenzel, Richard P

    2010-10-01

    Over the last decade, methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged as serious pathogens in the nosocomial and community setting. Hospitalization costs associated with MRSA infections are substantially greater than those associated with methicillin-sensitive S. aureus (MSSA) infections, and MRSA has wider economic effects that involve indirect costs to the patient and to society. In addition, there is some evidence suggesting that MRSA infections increase morbidity and the risk of mortality. Glycopeptides are the backbone antibiotics for the treatment of MRSA infections. However, several recent reports have highlighted the limitations of vancomycin, and its role in the management of serious infections is now being reconsidered. Several new antimicrobials demonstrate in vitro activity against MRSA and other Gram-positive bacteria. Data from large surveys indicate that linezolid, daptomycin, and tigecycline are almost universally active against MRSA. This review will briefly discuss the epidemiology, costs, outcome, and therapeutic options for the management of MRSA infections.

  1. Methicillin-resistant Staphylococcus pseudintermedius in Sweden.

    PubMed

    Börjesson, Stefan; Landén, Annica; Bergström, Martin; Andersson, Ulrika Grönlund

    2012-12-01

    Staphylococcus pseudintermedius is an opportunistic pathogen that is one of the most frequent causes of infections in dogs. In Europe, there are increasing reports of methicillin-resistant S. pseudintermedius (MRSP), and in Sweden, MRSP has also been more frequently isolated during recent years. However, there is limited knowledge regarding the epidemiology and genetic relationship among the Swedish isolates. This study therefore investigated the genetic relationship of MRSP isolated from companion animals in Sweden. In the study, MRSP isolates taken in the period January 2008-June 2010 from a total of 226 dogs and cats were characterized by spa typing, pulsed-field gel electrophoresis, and antimicrobial susceptibility testing. In addition, the geographical distribution of the isolates based on year of isolation and genetic typing was determined using a geographical information system. One multiresistant clonal lineage dominated among Swedish MRSP isolates, corresponding to the European winning lineage ST71-J-t02-SCCmec II-III. Furthermore, the geographical dissemination of MRSP corresponded to areas with high dog densities, centered on the three major cities in Sweden where the largest animal hospitals are situated.

  2. Methicillin-resistant Staphylococcus aureus in animals.

    PubMed

    Weese, J Scott

    2010-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a critically important human pathogen that is also an emerging concern in veterinary medicine and animal agriculture. It is present in a wide range of animal species, including dogs, cats, rabbits, horses, cattle, pigs, poultry, and exotic species, both as a cause of infection and in healthy carriers. Identification of MRSA in various species and in food has led to concerns about the roles of animals, both pets and livestock, in the epidemiology of MRSA infection and colonization in humans. There is evidence of the role of food animals in human MRSA infections in some countries and of pets as a possible source of human infection. Some groups of individuals who work closely with animals, such as veterinarians, have high MRSA colonization rates. This article includes discussions of MRSA in human medicine, animals, and food, as well as its interspecies transmission, colonization, infection, strains, and affected populations. However, clear answers are lacking in many of these areas and limited studies may lead to premature conclusions. It is certain that animals are a source of human MRSA infection in some circumstances--but humans may also serve as sources of infection in animals. Changes in the epidemiology of MRSA in one species may be reflected in changes in other species. The true scope of MRSA in animals and its impact on human health are still only superficially understood, but it is clear that MRSA is a potentially important veterinary and public health concern that requires a great deal more study to enhance understanding and effective response.

  3. Implementation of an industrial systems-engineering approach to reduce the incidence of methicillin-resistant Staphylococcus aureus infection.

    PubMed

    Muder, Robert R; Cunningham, Candace; McCray, Ellesha; Squier, Cheryl; Perreiah, Peter; Jain, Rajiv; Sinkowitz-Cochran, Ronda L; Jernigan, John A

    2008-08-01

    To measure the effectiveness of an industrial systems-engineering approach to a methicillin-resistant Staphylococcus aureus (MRSA) prevention program. Before-after intervention study. An intensive care unit (ICU) and a surgical unit that was not an ICU in the Pittsburgh Veterans Administration hospital. All patients admitted to the study units. We implemented an MRSA infection control program that consisted of the following 4 elements: (1) the use of standard precautions for all patient contact, with emphasis on hand hygiene; (2) the use of contact precautions for interactions with patients known to be infected or colonized with MRSA; (3) the use of active surveillance cultures to identify patients who were asymptomatically colonized with MRSA; and (4) use of an industrial systems-engineering approach, the Toyota Production System, to facilitate consistent and reliable adherence to the infection control program. The rate of healthcare-associated MRSA infection in the surgical unit decreased from 1.56 infections per 1,000 patient-days in the 2 years before the intervention to 0.63 infections per 1,000 patient-days in the 4 years after the intervention (a 60% reduction; P = .003). The rate of healthcare-associated MRSA infection in the ICU decreased from 5.45 infections per 1,000 patient-days in the 2 years before to the intervention to 1.35 infections per 1,000 patient-days in the 3 years after the intervention (a 75% reduction; P = .001). The combined estimate for reduction in the incidence of infection after the intervention in the 2 units was 68% (95% confidence interval, 50%-79%; P < .001). Sustained reduction in the incidence of MRSA infection is possible in a setting where this pathogen is endemic. An industrial systems-engineering approach can be adapted to facilitate consistent and reliable adherence to MRSA infection prevention practices in healthcare facilities.

  4. 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

  5. USA300 Methicillin-resistant Staphylococcus aureus in Cuba

    PubMed Central

    2012-01-01

    Background Methicillin-resistant Staphylococcus aureus is an increasing problem in the Caribbean. We investigated the molecular epidemiology of MRSA isolates on Cuba. Findings The predominant clone was of the spa type t149, followed by community-associated MRSA USA300. Conclusions We report the first molecular typing results of MRSA isolates from Cuba. PMID:22958408

  6. The Epidemiology of Methicillin-Resistant Staphylococcus aureus in Orthopaedics.

    PubMed

    Atkinson Smith, Mary

    2015-01-01

    In the specialty of orthopaedics, methicillin-resistant Staphylococcus aureus (MRSA) is a major contributor to infections of the soft tissues, surgical sites, and joints, in addition to increasing disability, mortality, and healthcare costs. Inappropriate prescribing and misuse of antibiotics have led to bacterial resistance and the rapid emergence of MRSA. It is imperative for healthcare providers and facilities to improve quality, promote safety, and decrease costs related to MRSA infections. The healthcare profession and society as a whole play an important role in minimizing the transmission of pathogens, reducing the incidence of MRSA infections, and decreasing the development of future antibiotic resistant pathogens. This article discusses the epidemiology of MRSA and describes evidence-based guidelines pertaining to the prevention, minimization, and treatment of MRSA-related infections. Specific application to orthopaedics are discussed in the context of patient risk factors, perioperative and postoperative prophylaxis, and current trends regarding education and reporting strategies.

  7. Estimating the Effectiveness of Isolation and Decolonization Measures in Reducing Transmission of Methicillin-resistant Staphylococcus aureus in Hospital General Wards

    PubMed Central

    Worby, Colin J.; Jeyaratnam, Dakshika; Robotham, Julie V.; Kypraios, Theodore; O'Neill, Philip D.; De Angelis, Daniela; French, Gary; Cooper, Ben S.

    2013-01-01

    Infection control for hospital pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) often takes the form of a package of interventions, including the use of patient isolation and decolonization treatment. Such interventions, though widely used, have generated controversy because of their significant resource implications and the lack of robust evidence with regard to their effectiveness at reducing transmission. The aim of this study was to estimate the effectiveness of isolation and decolonization measures in reducing MRSA transmission in hospital general wards. Prospectively collected MRSA surveillance data from 10 general wards at Guy's and St. Thomas' hospitals, London, United Kingdom, in 2006–2007 were used, comprising 14,035 patient episodes. Data were analyzed with a Markov chain Monte Carlo algorithm to model transmission dynamics. The combined effect of isolation and decolonization was estimated to reduce transmission by 64% (95% confidence interval: 37, 79). Undetected MRSA-positive patients were estimated to be the source of 75% (95% confidence interval: 67, 86) of total transmission events. Isolation measures combined with decolonization treatment were strongly associated with a reduction in MRSA transmission in hospital general wards. These findings provide support for active methods of MRSA control, but further research is needed to determine the relative importance of isolation and decolonization in preventing transmission. PMID:23592544

  8. Estimating the effectiveness of isolation and decolonization measures in reducing transmission of methicillin-resistant Staphylococcus aureus in hospital general wards.

    PubMed

    Worby, Colin J; Jeyaratnam, Dakshika; Robotham, Julie V; Kypraios, Theodore; O'Neill, Philip D; De Angelis, Daniela; French, Gary; Cooper, Ben S

    2013-06-01

    Infection control for hospital pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) often takes the form of a package of interventions, including the use of patient isolation and decolonization treatment. Such interventions, though widely used, have generated controversy because of their significant resource implications and the lack of robust evidence with regard to their effectiveness at reducing transmission. The aim of this study was to estimate the effectiveness of isolation and decolonization measures in reducing MRSA transmission in hospital general wards. Prospectively collected MRSA surveillance data from 10 general wards at Guy's and St. Thomas' hospitals, London, United Kingdom, in 2006-2007 were used, comprising 14,035 patient episodes. Data were analyzed with a Markov chain Monte Carlo algorithm to model transmission dynamics. The combined effect of isolation and decolonization was estimated to reduce transmission by 64% (95% confidence interval: 37, 79). Undetected MRSA-positive patients were estimated to be the source of 75% (95% confidence interval: 67, 86) of total transmission events. Isolation measures combined with decolonization treatment were strongly associated with a reduction in MRSA transmission in hospital general wards. These findings provide support for active methods of MRSA control, but further research is needed to determine the relative importance of isolation and decolonization in preventing transmission.

  9. 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.

  10. Laboratory Maintenance of Methicillin-Resistant Staphylococcus aureus (MRSA)

    PubMed Central

    Vitko, Nicholas P.; Richardson, Anthony R.

    2014-01-01

    Staphylococcus aureus is an important bacterial pathogen in the hospital and community settings, especially Staphylococcus aureus clones that exhibit methicillin-resistance (MRSA). Many strains of S. aureus are utilized in the laboratory, underscoring the genetic differences inherent in clinical isolates. S. aureus grows quickly at 37°C with aeration in rich media (e.g. BHI) and exhibits a preference for glycolytic carbon sources. Furthermore, S. aureus has a gold pigmentation, exhibits β-hemolysis, and is catalase and coagulase positive. The four basic laboratory protocols presented in this unit describe how to culture S. aureus on liquid and solid media, how to identify S. aureus strains as methicillin resistant, and how to generate a freezer stock of S. aureus for long-term storage. PMID:23408135

  11. Laboratory maintenance of methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Vitko, Nicholas P; Richardson, Anthony R

    2013-02-01

    Staphylococcus aureus is an important bacterial pathogen in the hospital and community settings, especially Staphylococcus aureus clones that exhibit methicillin-resistance (MRSA). Many strains of S. aureus are utilized in the laboratory, underscoring the genetic differences inherent in clinical isolates. S. aureus grows quickly at 37°C with aeration in rich media (e.g., BHI) and exhibits a preference for glycolytic carbon sources. Furthermore, S. aureus has a gold pigmentation, exhibits β-hemolysis, and is catalase and coagulase positive. The four basic laboratory protocols presented in this unit describe how to culture S. aureus on liquid and solid media, how to identify S. aureus strains as methicillin resistant, and how to generate a freezer stock of S. aureus for long-term storage. © 2013 by John Wiley & Sons, Inc.

  12. Fosfomycin susceptibility of canine methicillin-resistant Staphylococcus pseudintermedius isolates.

    PubMed

    DiCicco, Matthew; Weese, Scott; Neethirajan, Suresh; Rousseau, Joyce; Singh, Ameet

    2014-04-01

    The effectiveness of fosfomycin was examined across 31 methicillin-resistant Staphylococcus pseudintermedius (MRSP) strains by agar dilution. Prevalence of the fosfomycin-resistance determinant gene, fosB, was assessed by PCR analysis. Results found that 84% of isolates were fosfomycin-susceptible. Interestingly, 87% of isolates possessed fosB, indicating no association between this putative staphylococci resistance gene and phenotypic resistance. Further evaluation of fosfomycin as a potential treatment of MRSP in dogs is warranted.

  13. Treatment of Methicillin-Resistant Staphylococcus aureus Bacteremia

    PubMed Central

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of health care-associated infections. Vancomycin remains an acceptable treatment option. There has been a welcome increase in the number of agents available for the treatment of MRSA infection. These drugs have certain differentiating attributes and may offer some advantages over vancomycin, but they also have significant limitations. These agents provide some alternative when no other options are available. PMID:28032484

  14. Methicillin-resistant Staphylococcus aureus in HIV-infected patients

    PubMed Central

    Hidron, Alicia I; Kempker, Russell; Moanna, Abeer; Rimland, David

    2010-01-01

    Concordant with the emergence of methicillin-resistant Staphylococcus aureus (MRSA) in the community setting, colonization and infections with this pathogen have become a prevalent problem among the human immunodeficiency virus (HIV)-positive population. A variety of different host- and, possibly, pathogen-related factors may play a role in explaining the increased prevalence and incidence observed. In this article, we review pathophysiology, epidemiology, clinical manifestations, and treatment of MRSA in the HIV-infected population. PMID:21694896

  15. The femR315 gene from Staphylococcus aureus, the interruption of which results in reduced methicillin resistance, encodes a phosphoglucosamine mutase.

    PubMed Central

    Jolly, L; Wu, S; van Heijenoort, J; de Lencastre, H; Mengin-Lecreulx, D; Tomasz, A

    1997-01-01

    The femR315 gene was recently identified by Tn551 insertional mutagenesis as one of the new auxiliary genes, the alteration of which resulted in a drastically reduced methicillin resistance of the Staphylococcus aureus strain COL. femR315 (also known as femD) theoretically encoded a protein of 451 amino acids showing significant amino acid sequence homology with phosphoglucomutases and similar enzymes catalyzing the isomerization of hexoses and hexosamine phosphates (S. Wu, H. de Lencastre, A. Sali, and A. Tomasz, Microb. Drug Resist. 2:277-286, 1996). We describe here the overproduction and purification of the FemR315 protein as well as its identification as the phosphoglucosamine mutase which catalyzes the formation of glucosamine-1-phosphate from glucosamine-6-phosphate, the first step in the reaction sequence leading to the essential peptidoglycan precursor UDP-N-acetylglucosamine. On the basis of these findings, we propose to change the names femR315 and femD to the functionally more appropriate name glmM. PMID:9286983

  16. Subinhibitory fluoroquinolone exposure selects for reduced beta-lactam susceptibility in methicillin-resistant Staphylococcus aureus and alterations in the SOS-mediated response.

    PubMed

    Tattevin, Pierre; Basuino, Li; Chambers, Henry F

    2009-04-01

    Growth of fluoroquinolone (FQ)-susceptible methicillin-resistant Staphylococcus aureus (MRSA) in the presence of sub-MIC FQ has been shown to enhance methicillin resistance in traditional nosocomial MRSA isolates. We aimed to confirm this phenomenon in nine community-associated MRSA (CA-MRSA) clinical isolates, and to identify candidate genes that might account for this unusual phenotype. Overnight growth of CA-MRSA strains in tryptic soy broth containing a subinhibitory concentration of either ciprofloxacin or levofloxacin resulted in a concentration-related increase in the number of colonies that grew on nafcillin agar, such that about one CFU in four exhibited significantly higher resistance to nafcillin, with only a modest increase in FQ MIC. No mutations were found in the quinolone-resistance determining region of gyrA and grlA. DNA microarray studies of a representative levofloxacin-exposed clone found that gene expression was increased for 53 open reading frames (ORFs), including norR and mecA, and decreased for 10. The majority of these ORFs encode regulatory and stress response proteins. In conclusion, sublethal exposure to FQ alters the SOS response in CA-MRSA and selects in a non-lethal manner for stable mutants with enhanced expression of methicillin resistance.

  17. In vitro and in vivo study of fosfomycin in methicillin-resistant Staphylococcus aureus septicaemia.

    PubMed Central

    Lau, W. Y.; Teoh-Chan, C. H.; Fan, S. T.; Lau, K. F.

    1986-01-01

    Five hundred strains of methicillin-resistant Staphylococcus aureus were tested against various anti-staphylococcal agents. Vancomycin, fusidic acid and fosfomycin were found to be the most effective. Only 1 strain out of 500 was resistant to fosfomycin. Three patients with methicillin-resistant Staphylococcus aureus septicaemia were successfully treated by fosfomycin. We conclude that fosfomycin could be the drug of choice for methicillin-resistant Staphylococcus aureus infection. PMID:3637200

  18. Methicillin-resistant Staphylococcus aureus: source control and surveillance organization.

    PubMed

    Tacconelli, E

    2009-12-01

    Methicillin-resistant Staphylococcus aureus (MRSA) has been a common nosocomial pathogen since the 1960s, and has become a major problem in hospitals worldwide. Patients and the public are increasingly seeing MRSA and rates of MRSA infections as indicators of the quality of patient care. The control measures aimed at reducing the spread of MRSA among hospitals and communities include the following: education of healthcare workers, with implementation and adherence to hand-washing practices; restriction of antibiotic use; active surveillance cultures (ASCs); contact isolation of MRSA-positive patients; and pre-emptive isolation of high-risk patients. However, despite these interventions, MRSA is still endemic in many hospitals worldwide. In particular, the role of ASCs is still under debate. International guidelines suggest that extensive ASCs should only be used in intensive-care units (ICUs), and routine screening of all hospital admissions is not usually advocated. Local decisions can be made on the basis of types of risk factor of non-ICU patients. Before starting ASCs, laboratories should be prepared for the workload, and the turn-around time for screening tests should be reduced and arrangements made to monitor the effectiveness of this intervention. Most recently, rapid methods for molecular detection of MRSA colonization have been developed. Published studies differ in their settings (ICU, medical wards, surgical wards), choice of patient population, severity of illness, hospital infection control measures, and study design. The existing evidence does not support the wide application of rapid molecular screening for MRSA.

  19. Impact of Molecular Epidemiology and Reduced Susceptibility to Glycopeptides and Daptomycin on Outcomes of Patients with Methicillin-Resistant Staphylococcus aureus Bacteremia

    PubMed Central

    Lee, Hao-Yuan; Chen, Chyi-Liang; Liu, Shu-Ying; Yan, Yu-Shan; Chang, Chee-Jen; Chiu, Cheng-Hsun

    2015-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia was associated with high mortality, but the risk factors associated with mortality remain controversial. Methods A retrospective cohort study was designed. All patients with MRSA bacteremia admitted were screened and collected for their clinical presentations and laboratory characteristics. Minimum inhibitory concentration (MIC) and staphylococcal cassette chromosome mec (SCCmec) type of bacterial isolates were determined. Risk factors for mortality were analyzed. Results Most MRSA isolates from the 189 enrolled patients showed reduced susceptibility to antibiotics, including MIC of vancomycin ≥ 1.5 mg/L (79.9%), teicoplanin ≥ 2 mg/L (86.2%), daptomycin ≥ 0.38 mg/L (73.0%) and linezolid ≥ 1.5 mg/L (64.0%). MRSA with vancomycin MIC ≥ 1.5 mg/L and inappropriate initial therapy were the two most important risk factors for mortality (both P < 0.05; odds ratio = 7.88 and 6.78). Hospital-associated MRSA (HA-MRSA), carrying SCCmec type I, II, or III, was associated with reduced susceptibility to vancomycin, teicoplanin or daptomycin and also with higher attributable mortality (all P < 0.05). Creeping vancomycin MIC was linked to higher MIC of teicoplanin and daptomycin (both P < 0.001), but not linezolid (P = 0.759). Conclusions Giving empirical broad-spectrum antibiotics for at least 5 days to treat catheter-related infections, pneumonia, soft tissue infection and other infections was the most important risk factor for acquiring subsequent HA-MRSA infection. Choice of effective anti-MRSA agents for treating MRSA bacteremia should be based on MIC of vancomycin, teicoplanin and daptomycin. Initiation of an effective anti-MRSA agent without elevated MIC in 2 days is crucial for reducing mortality. PMID:26295150

  20. 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

  1. Methicillin-resistant Staphylococcus pseudintermedius in a veterinary teaching hospital.

    PubMed

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

    2007-04-01

    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 mug/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.

  2. Nasal Methicillin-Resistant Staphylococcus aureus (MRSA) PCR Testing Reduces the Duration of MRSA-Targeted Therapy in Patients with Suspected MRSA Pneumonia.

    PubMed

    Baby, Nidhu; Faust, Andrew C; Smith, Terri; Sheperd, Lyndsay A; Knoll, Laura; Goodman, Edward L

    2017-04-01

    The objective of this study was to evaluate the impact of pharmacist-ordered methicillin-resistant Staphylococcus aureus (MRSA) PCR testing on the duration of empirical MRSA-targeted antibiotic therapy in patients with suspected pneumonia. This is a retrospective analysis of patients who received vancomycin or linezolid for suspected pneumonia before and after the implementation of a pharmacist-driven protocol for nasal MRSA PCR testing. Patients were included if they were adults of >18 years of age and initiated on vancomycin or linezolid for suspected MRSA pneumonia. The primary endpoint was the duration of vancomycin or linezolid therapy. After screening 368 patients, 57 patients met inclusion criteria (27 pre-PCR and 30 post-PCR). Baseline characteristics were similar between the two groups, with the majority of patients classified as having health care-associated pneumonia (68.4%). The use of the nasal MRSA PCR test reduced the mean duration of MRSA-targeted therapy by 46.6 h (74.0 ± 48.9 h versus 27.4 ± 18.7 h; 95% confidence interval [CI], 27.3 to 65.8 h; P < 0.0001). Fewer patients in the post-PCR group required vancomycin serum levels and dose adjustment (48.1% versus 16.7%; P = 0.02). There were no significant differences between the pre- and post-PCR groups regarding days to clinical improvement (1.78 ± 2.52 versus 2.27 ± 3.34; P = 0.54), length of hospital stay (11.04 ± 9.5 versus 8.2 ± 7.8; P = 0.22), or hospital mortality (14.8% versus 6.7%; P = 0.41). The use of nasal MRSA PCR testing in patients with suspected MRSA pneumonia reduced the duration of empirical MRSA-targeted therapy by approximately 2 days without increasing adverse clinical outcomes.

  3. High Prevalence of Isolates with Reduced Glycopeptide Susceptibility in Persistent or Recurrent Bloodstream Infections Due to Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Uçkay, Ilker; Bernard, Louis; Buzzi, Marta; Harbarth, Stephan; François, Patrice; Huggler, Elzbieta; Ferry, Tristan; Schrenzel, Jacques; Renzoni, Adriana; Lew, Daniel P.

    2012-01-01

    Reduced susceptibility to glycopeptides in methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates is considered a risk factor for failure of glycopeptide therapy. We compared the prevalences of MRSA isolates with reduced glycopeptide susceptibility in patients with versus without persistent or recurrent MRSA bloodstream infections. A retrospective cohort study at the University Hospital of Geneva identified 27 patients with persistent or recurrent clonally related MRSA bacteremic episodes over an 8-year period, which included 208 consecutive nosocomial MRSA bacteremic episodes. Vancomycin and teicoplanin MICs were determined by a modified macrodilution assay allowing improved detection of glycopeptide-intermediate MRSA isolates (GISA), characterized by elevated teicoplanin or/and vancomycin MICs (≥4 μg/ml). For 16 patients (59%), their pretherapy and/or posttherapy MRSA isolates showed elevated teicoplanin MICs, among which 10 (37%) concomitantly displayed elevated vancomycin MICs. In contrast, 11 other patients (41%) were persistently or recurrently infected with non-GISA isolates. In comparison, only 39 (22%) of 181 single isolates from patients with no microbiological evidence of persistent or recurrent infections showed elevated teicoplanin MICs, among which 14 (8%) concomitantly displayed elevated vancomycin MICs. Clinical, microbiological, and pharmacokinetic variables for patients persistently or recurrently infected with GISA or non-GISA isolates were similar. Bacteremic patients with a poor response to glycopeptide therapy had a 2.8-fold- and 4.8-fold-higher rates of MRSA isolates displaying elevated teicoplanin and vancomycin MICs, respectively, than patients with single isolates (P < 0.0001). Detection of elevated teicoplanin MICs may help to predict a poor response to glycopeptide therapy in MRSA bacteremic patients. PMID:22155824

  4. Reduced Susceptibility to Host-Defense Cationic Peptides and Daptomycin Coemerge in Methicillin-Resistant Staphylococcus aureus From Daptomycin-Naive Bacteremic Patients

    PubMed Central

    Mishra, Nagendra N.; Bayer, Arnold S.; Moise, Pamela A.; Yeaman, Michael R.; Sakoulas, George

    2012-01-01

    Background. We hypothesized that, for methicillin-resistant Staphylococcus aureus (MRSA), in vitro daptomycin susceptibility could be influenced by exposures to endogenous host defense peptides (HDPs) prior to clinical exposure to daptomycin. Methods. Two endovascular HDPs were used: thrombin-induced platelet microbicidal protein (tPMP) and human neutrophil defensin-1 (hNP-1) from neutrophils. Forty-seven unique MRSA isolates obtained from bacteremic patients in multicenter prospective clinical trials were studied. Clinical characteristics, microbiologic parameters, prior vancomycin therapy, and susceptibilities to tPMP, hNP-1, and daptomycin were compared using univariate and multivariate analyses. Results. All strains were daptomycin susceptible. Daptomycin minimum inhibitory concentrations (MICs) were inversely related to in vitro tPMP (but not hNP-1) killing. Strains with a daptomycin MIC of 1 mg/L exhibited significantly less killing by tPMP, compared with strains with an MIC of ≤ 0.5 mg/L. Prior vancomycin therapy did not influence this relationship. Regression tree modeling confirmed that reduced tPMP-induced killing in vitro was the strongest predictor of higher daptomycin MICs within the daptomycin-susceptible range. Conclusions. Among daptomycin-susceptible MRSA isolates from patients who had never received daptomycin, higher daptomycin MICs tracked with increased resistance to killing by platelet-derived but not neutrophil-derived HDPs. These findings support the notion that endogenous exposure of MRSA to specific HDPs may play a role in selecting strains with an intrinsically higher daptomycin MIC phenotype. PMID:22904338

  5. Comparative Efficacy of Ceftaroline with Linezolid against Staphylococcus aureus and Methicillin Resistant Staphylococcus aureus.

    PubMed

    Hafeez, Amira; Munir, Tehmina; Rehman, Sabahat; Najeeb, Sara; Gilani, Mehreen; Latif, Mahwish; Ansari, Maliha; Saad, Nadia

    2015-04-01

    To compare the in vitro antimicrobial efficacy of ceftaroline with linezolid against Staphylococcus aureus and methicillin resistant Staphylococcus aureus. Quasi-experimental study. Microbiology Department, Army Medical College, Rawalpindi, from January to December 2013. Clinical samples from respiratory tract, blood, pus and various catheter tips routinely received in the Department of Microbiology, Army Medical College, Rawalpindi were innoculated on blood and MacConkey agar. Staphylococcus aureus was identified by colony morphology, Gram reaction, catalase test and coagulase test. Methicillin resistant Staphylococcus aureus detection was done by modified Kirby Bauer disc diffusion method using cefoxitin disc (30 μg) and the isolates were considered methicillin resistant if the zone of inhibition around cefoxitin disc was ≤ 21 mm. Bacterial suspensions of 56 Staphylococcus aureus isolates and 50 MRSA isolates were prepared, which were standardized equal to 0.5 McFarland's turbidity standard and inoculated on Mueller-Hinton agar plates followed by application of ceftaroline and linezolid disc (Oxoid, UK), according to manufacturer's instructions. The plates were then incubated at 37 °C aerobically for 18 - 24 hours. Diameters of inhibition zone were measured and interpretated as per Clinical and Laboratory Standards Institute (CLSI) guidelines. Out of 106 isolates all of the 56 Staphylococcus aureus (100%) were sensitive to ceftaroline and linezolid. However, out of 50 methicillin resistant Staphylococcus aureus, 48 (96%) were sensitive to ceftaroline whereas, 49 (98%) were sensitive to linezolid. Ceftaroline is equally effective as linezolid against Staphylococcus aureus and methicillin resistant Staphylococcus aureus.

  6. 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

  7. 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.

  8. Cataract surgery during active methicillin-resistant Staphylococcus aureus infection.

    PubMed

    Mansour, Ahmad M; Salti, Haytham I

    2014-01-01

    We present two patients with active, foul-smelling, methicillin-resistant Staphylococcus aureus (MRSA) wounds of the forehead and sternum following craniotomy or open heart surgery. Both had debilitating cataracts and were told by the infectious diseases team that cataract surgery is very risky. Both underwent sequential bilateral phacoemulsification with no sign of infection. Patients with active MRSA wound infections may safely undergo cataract surgery with additional precautions observed intraoperatively (good wound construction) and postoperatively (topical antibiotics and close observation). Banning such surgeries can unnecessarily jeopardize the lifestyles of such patients.

  9. Cutaneous myiasis masquerading as methicillin-resistant Staphylococcus aureus.

    PubMed

    Lopez, Jonathan J; Coris, Eric E

    2013-09-01

    Numerous factors place athletes at increased risk for cutaneous infections, and as such, they are a common complaint in athletic training rooms. Methicillin-resistant Staphylococcus aureus (MRSA) is an increasingly common etiology, and given its severe sequelae, a high index of suspicion in this population is justified. We present 2 cases of college athletes who presented to the athletic training room with findings suspicious for MRSA infection. However, after further investigation, the true diagnosis of myiasis was reached. These cases highlight the importance of asking athletes about recent travel and considering a broad differential diagnosis when evaluating furuncular lesions.

  10. 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.

  11. Daptomycin-nonsusceptible, vancomycin-intermediate, methicillin-resistant Staphylococcus aureus endocarditis

    PubMed Central

    Yu, Ryan; Dale, Suzanne E; Yamamura, Deborah; Stankus, Vida; Lee, Christine

    2012-01-01

    Due to the emergence of Staphylococcus aureus with reduced vancomycin susceptibility, newer antibiotics, including daptomycin, have been used to treat methicillin-resistant S aureus infections. Daptomycin is a cyclic lipopeptide that is approved to treat S aureus bacteremia and right-sided endocarditis, and reports of S aureus with reduced susceptibility to daptomycin are infrequent. To our knowledge, the present report describes the first Canadian case of daptomycin-nonsusceptible, vancomycin-intermediate S aureus infection. PMID:23730321

  12. 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…

  13. 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…

  14. Methicillin-resistant Staphylococcus aureus in palliative care: A prospective study of Methicillin-resistant Staphylococcus aureus prevalence in a hospital-based palliative care unit.

    PubMed

    Schmalz, Oliver; Strapatsas, Tobias; Alefelder, Christof; Grebe, Scott Oliver

    2016-07-01

    Methicillin-resistant Staphylococcus aureus is a common organism in hospitals worldwide and is associated with morbidity and mortality. However, little is known about the prevalence in palliative care patients. Furthermore, there is no standardized screening protocol or treatment for patients for whom therapy concentrates on symptom control. Examining the prevalence of methicillin-resistant Staphylococcus aureus in palliative care patients as well as the level of morbidity and mortality. We performed a prospective study where methicillin-resistant Staphylococcus aureus screening was undertaken in 296 consecutive patients within 48 h after admission to our palliative care unit. Medical history was taken, clinical examination was performed, and the Karnofsky Performance Scale and Palliative Prognostic Score were determined. Prevalence of Methicillin-resistant Staphylococcus aureus was compared to data of general hospital patients. In total, 281 patients were included in the study having a mean age of 69.7 years (standard deviation = 12.9 years) and an average Karnofsky Performance Scale between 30% and 40%. The mean length of stay was 9.7 days (standard deviation = 7.6 days). A total of 24 patients were methicillin-resistant Staphylococcus aureus positive on the first swab. Median number of swabs was 2. All patients with a negative methicillin-resistant Staphylococcus aureus swab upon admission remained Methicillin-resistant Staphylococcus aureus negative in all subsequent swabs. Our study suggests that the prevalence of Methicillin-resistant Staphylococcus aureus among patients in an in-hospital palliative care unit is much higher than in other patient populations. © The Author(s) 2016.

  15. Methicillin-resistant Staphylococcus aureus (mrsa) in a Malaysian hospital.

    PubMed

    Cheong, I; Tan, S C; Wong, Y H; Zainudin, B M; Rahman, M Z

    1994-03-01

    Between August 1990 to November 1991, 905 of 2583 (35.4%) isolates of Staphylococcus aureus were found to be methicillin-resistant in a general hospital in Malaysia. A detailed study of 539 of these isolates showed a high prevalence of methicillin resistant Staphylococcus aureus (MRSA) in the surgical/orthopaedic wards, paediatric wards and the special care unit. The yield of MRSA was highest from wounds/ulcers/skin swabs accounting for 64.2 per cent followed by 6.9 per cent in blood cultures. Vancomycin remains the drug of choice with no resistance detected. The resistance to ciprofloxacin was 6.7 per cent, rifampicin 4.5 per cent and fusidic acid 2.0 per cent. Most isolates were resistant to aminoglycosides. In view of the high prevalence of MRSA in this hospital, the authorities must introduce more effective measures to control its spread as a nosocomial pathogen. Otherwise it may seriously disrupt the efficient delivery of health care services in the country.

  16. Antimicrobial blue light inactivation of Methicillin-resistant Staphylococcus aureus

    NASA Astrophysics Data System (ADS)

    Wang, Yucheng; Dai, Tianhong; Gu, Ying

    2016-10-01

    Background: With the increasing emergence of multidrug-resistant (MDR) bacterial strains, there is a pressing need for the development of alternative treatment for infections. Antimicrobial blue light (aBL) has provided a simple and effective approach. Methods: We first investigated the effectiveness of aBL (415 nm) inactivation of USA300 LAClux (a communityacquired Methicillin-resistant Staphylococcus aureus strain) both in the planktonic and biofilm forms. The survival of the bacteria in suspensions was determined by serial dilution and that of the biofilm-embedded bacteria was determined by bioluminescence quantification. Using a mouse model of thermal burn infected with USA300 LAClux, we further assessed the effectiveness of aBL for treating localized infections. Bioluminescence imaging was performed to monitor in real time bacterial viability in vivo. Results: In vitro study showed that, for the planktonic counterpart of the bacteria or the 24-h-old biofilms, an irradiance of 55 mW/cm2 for 60 min resulted in a 4.61 log10 or 2.56 log10 inactivation, respectively. In vivo study using infected mouse burns demonstrated that a 2.56-log10 inactivation was achieved after 100-mW/cm2 irradiation for 62 min. Conclusions: aBL is a potential alternative approach for treating Methicillin-resistant Staphylococcus aureus infections.

  17. Methicillin-resistant Staphylococcus aureus diagnostics: state of the art.

    PubMed

    Baron, Ellen Jo; Tenover, Fred C

    2012-11-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is among the most common causes of community- and healthcare-acquired infections, accounting for > 80,000 invasive infections in the United States in 2010 according to the Center for Disease Control and Prevention's Active Bacterial Core Surveillance data. Control and treatment of MRSA depend on reliable identification, which is challenging. This article reviews the current status of detection and identification of MRSA. Publications since 2001, guidelines from the Clinical Laboratory Standards Institute and the European Committee on Antimicrobial Susceptibility Testing, common microbiology laboratory practices for identification and characterization of MRSA in human samples, and recent publications that assessed patient care outcomes of various detection and intervention strategies were surveyed for this review. Given the predilection of Staphylococcus aureus to modify its genetic characteristics, thereby enabling the species to stay one step ahead of laboratory detection systems, phenotypic methods for detection of antibiotic resistance mechanisms, especially those directed against the beta-lactam family, will continue to be required, in some situations, for the foreseeable future. Molecular methods are now the gold standard for surveillance, yielding higher sensitivity than the slower, culture-based methods. The newer molecular surveillance methods for detecting methicillin-resistant S. aureus (MRSA) colonization and for rapid and accurate identification of S. aureus from growth in culture systems have revolutionized patient care, enabling rapid interventions that lead to better individual patient outcomes, such as fewer postsurgical site infections, and better overall institutional infection control (fewer healthcare-associated MRSA infections).

  18. Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Screening and Decolonization to Reduce Surgical Site Infection in Elective Total Joint Arthroplasty.

    PubMed

    Sporer, Scott M; Rogers, Thea; Abella, Linda

    2016-09-01

    Deep infection after elective total joint arthroplasty remains a devastating complication. Preoperative nasal swab screening for Staphylococcus aureus colonization and subsequent treatment of colonized patients is one proposed method to identify at-risk patients and decrease surgical site infections (SSIs). The purpose of this study was to determine whether a preoperative staphylococcus screening and treatment program would decrease the incidence of SSI in elective joint arthroplasty patients. Since January 2009, a total of 9690 patients having an elective joint arthroplasty were screened before surgery for Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) with nares swabs. All patients with positive nare colonization for MSSA and MRSA were treated with mupirocin and chlorhexidine gluconate showers for 5 days before surgery. MRSA patients received vancomycin preoperatively and were placed in contact isolation. All elective arthroplasty patients used chlorhexidine gluconate antiseptic cloths the evening prior and the day of surgery. Perioperative infection rates were compared from 1 year before implementation to 5 years after implementation of this screening protocol. SSI rates have decreased from 1.11% (prescreening) to 0.34% (nasal screening; P < .05) after initiation of the process. Staphylococcus was identified in 66.7% of the SSI infections before nasal screening and in 33.3% of the SSI after routine screening (P > .05). The addition of MRSA and/or MSSA nares screening along with a perioperative decolonization protocol has resulted in a decreased SSI rate by 69%. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Methicillin-resistant Staphylococcus aureus: a new zoonotic agent?

    PubMed

    Springer, Burkhard; Orendi, Ulrike; Much, Peter; Höger, Gerda; Ruppitsch, Werner; Krziwanek, Karina; Metz-Gercek, Sigrid; Mittermayer, Helmut

    2009-01-01

    Staphylococcus aureus is a major cause of infection in hospitals and the community. One third of the general population is colonized by the bacterium, constituting a risk factor for acquisition of infection with this pathogen. Worldwide, the increasing antibiotic resistance of S. aureus complicates treatment of infection and control measures. Soon after the introduction of methicillin, the first isolates resistant to this antibiotic were reported and named methicillin-resistant S. aureus (MRSA). During the past decade a major change in MRSA epidemiology has been observed: whereas in the past MRSA was almost exclusively regarded a hospital pathogen, the advent of community-acquired MRSA has led to infections in people without hospital-related risk factors. Recent evidence has also identified a link between colonization of livestock and MRSA carriage and infections in people who work with animals. Screening of pigs and pig farmers in the Netherlands revealed high prevalence of MRSA sequence type (ST) 398 and it has become clear that the emergence of ST398 is not just a Dutch problem, as reports on livestock colonization and human infections are appearing worldwide. In Austria, the ST398 lineage has been detected in dust samples from pig breeding facilities and in food samples. Since the first Austrian detection of this emerging lineage in 2006, 21 human isolates, partially associated with infections, have been observed. MRSA has to be regarded as a new emerging zoonotic agent and livestock may constitute a growing reservoir of the ST398 lineage. More information is needed so that control measures to reduce the impact of the emerging MRSA ST398 lineage on public health can be developed and implemented.

  20. Prevention and control of methicillin-resistant Staphylococcus aureus.

    PubMed

    Humphreys, H; Grundmann, H; Skov, R; Lucet, J-C; Cauda, R

    2009-02-01

    Recent efforts to combat infections have focused on pharmaceutical interventions. However, the global spread of antimicrobial resistance calls for the reappraisal of personal and institutional hygiene. Hygiene embodies behavioural and procedural rules that prevent bacterial transmission. Consequently, the chance of spreading bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) is significantly reduced. Hygiene is part of the primacy and totality of patient care, ensuring that no harm is done. Any prevention and control strategy must be underpinned by changes in attitude, embraced by all. The major components of preventing and controlling MRSA include hand and environmental hygiene (as part of standard precautions), patient isolation, and patient/staff decolonization. Improving hand hygiene practice is especially important where the risk of infection is highest, e.g. in intensive care. Physical isolation has two advantages: the physical barrier interrupts transmission, and this barrier emphasizes that precautions are required. With limited isolation facilities, risk assessment should be conducted to indicate which patients should be isolated. Environmental hygiene, although important, has a lower priority than standard precautions. When a patient is ready for discharge (home) or transfer (to another healthcare facility), the overall interests of the patient should take priority. All patients should be informed of their MRSA-positive status as soon as possible. Because of increased mupirocin resistance, a selective approach to decolonization should be taken. When MRSA-positive staff are identified, restricting their professional activity will depend on the nature of their work. Finally, politicians and others need to commit to providing the necessary resources to maximize MRSA prevention and control.

  1. Toxin Mediates Sepsis Caused by Methicillin-Resistant Staphylococcus epidermidis

    PubMed Central

    Qin, Li; Da, Fei; Tan, Daniel C. S.; Nguyen, Thuan H.; Fu, Chih-Lung; Tan, Vee Y.; Sturdevant, Daniel E.

    2017-01-01

    Bacterial sepsis is a major killer in hospitalized patients. Coagulase-negative staphylococci (CNS) with the leading species Staphylococcus epidermidis are the most frequent causes of nosocomial sepsis, with most infectious isolates being methicillin-resistant. However, which bacterial factors underlie the pathogenesis of CNS sepsis is unknown. While it has been commonly believed that invariant structures on the surface of CNS trigger sepsis by causing an over-reaction of the immune system, we show here that sepsis caused by methicillin-resistant S. epidermidis is to a large extent mediated by the methicillin resistance island-encoded peptide toxin, PSM-mec. PSM-mec contributed to bacterial survival in whole human blood and resistance to neutrophil-mediated killing, and caused significantly increased mortality and cytokine expression in a mouse sepsis model. Furthermore, we show that the PSM-mec peptide itself, rather than the regulatory RNA in which its gene is embedded, is responsible for the observed virulence phenotype. This finding is of particular importance given the contrasting roles of the psm-mec locus that have been reported in S. aureus strains, inasmuch as our findings suggest that the psm-mec locus may exert effects in the background of S. aureus strains that differ from its original role in the CNS environment due to originally “unintended” interferences. Notably, while toxins have never been clearly implied in CNS infections, our tissue culture and mouse infection model data indicate that an important type of infection caused by the predominant CNS species is mediated to a large extent by a toxin. These findings suggest that CNS infections may be amenable to virulence-targeted drug development approaches. PMID:28151994

  2. Isolation of methicillin-resistant Staphylococcus pseudintermedius from breeding dogs.

    PubMed

    Rota, Ada; Milani, Chiara; Drigo, Ilenia; Drigo, Michele; Corrò, Michela

    2011-01-01

    The overuse of antimicrobials can select resistant bacteria strains; staphylococci have the ability to become resistant to all beta-lactam antimicrobials and are a significant concern in human medicine and a growing issue for veterinary medicine. Because antimicrobials are sometimes incorrectly used in breeding kennels, the objective of the work was to assess the occurrence of methicillin-resistant coagulase-positive staphylococci in breeding dogs. The research was carried out in 13 kennels that were allotted to three categories according to the intensity of antimicrobial use. Vaginal and milk swabs were taken from 87 healthy bitches around parturition and also from multiple organs of 27 of their pups that died within the first 2 weeks. Standard bacteriological examinations were carried out and coagulase-positive staphylococci were identified. All the coagulase-positive staphylococci resulted to be Staphylococcus pseudintermedius. Susceptibility to oxacillin and the presence of the mecA gene were tested. Nine out of 89 strains (six isolated from the bitches' milk and three from dead puppies, all belonging to kennels characterized by an excessive use of antimicrobials) were multidrug-resistant, methicillin-resistant and mecA positive. Our results confirm that excessive use of antimicrobials entails the risk of selecting resistant staphylococci strains. Our data also indicate that the bacterial flora of healthy dogs belonging to specific populations may act as a reservoir of resistance genes.

  3. Modulation of Protein A Formation in Staphylococcus aureus by Genetic Determinants for Methicillin Resistance

    PubMed Central

    Cohen, Sidney; Sweeney, Helen M.

    1979-01-01

    Many methicillin-resistant (Mecr) strains of Staphylococcus aureus either produce no protein A or secrete it extracellularly (S. Winblad and C. Ericson, Acta Pathol. Microbiol. Scand. Sect. B 81:150–156, 1973). We found that methicillin resistance and protein A production were apparently lost coordinately from the natively Mecr strain A676. Restoration of the genetic determinant for methicillin resistance (mec) by transduction or transformation restored protein A production. In two other Mecr strains, loss of mec was accompanied by marked reduction in protein A formation. Genetic transfer of mec to derivatives of S. aureus 8325 affected protein A formation differently with different mec determinants. Those derived from strain A676 and two other Mecr strains reduced the scanty amount of protein A produced by strain 8325 to even lower or undetectable levels, whereas mec from two more Mecr strains increased its protein A content. This “mec-effect,” i.e., stimulation or inhibition of protein A formation dependent on the combination of host strain and mec determinant, was reduced in methicillin-susceptible (Mecs) mutants produced by ethyl methane sulfonate treatment of Mecr strains. The mec-effect reappeared in spontaneous revertants to methicillin resistance. Phenotypic reduction of methicillin resistance in Mecr strains grown at 44°C was accompanied by reduction of the mec-effect on protein A, but it had no effect on protein A formation in Mecs strains. Two independent mutants of strain 8325 produced large amounts of protein A at rates that were unaffected by growth at 44°C or by the introduction of mec determinants. PMID:533763

  4. Cloning and expression of methicillin resistance from Staphylococcus epidermidis in Staphylococcus carnosus.

    PubMed Central

    Tesch, W; Strässle, A; Berger-Bächi, B; O'Hara, D; Reynolds, P; Kayser, F H

    1988-01-01

    A 6.2-kilobase chromosomal DNA fragment from a methicillin-resistant Staphylococcus epidermidis strain was cloned into Staphylococcus carnosus by using staphylococcal plasmid pCA44 as the vector. The recombinant plasmid obtained, pBBB21, conferred methicillin resistance on its host and was responsible for the synthesis of a low-affinity penicillin-binding protein (PBP), PBP 2'. PBP 2' determined by the S. epidermidis DNA and expressed as a membrane-bound PBP in S. carnosus reacted with monoclonal antibodies directed against PBP 2' of Staphylococcus aureus origin, and the cloned S. epidermidis DNA hybridized to the methicillin (mec)-specific DNA from S. aureus. These findings point to a common origin of the methicillin resistance determinant in staphylococci. Images PMID:2903715

  5. 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

  6. 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.

  7. Antimicrobial Photodynamic Therapy for Methicillin-Resistant Staphylococcus aureus Infection

    PubMed Central

    Fu, Xiu-jun; Fang, Yong; Yao, Min

    2013-01-01

    Nowadays methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common multidrug resistant bacteria both in hospitals and in the community. In the last two decades, there has been growing concern about the increasing resistance to MRSA of the most potent antibiotic glycopeptides. MRSA infection poses a serious problem for physicians and their patients. Photosensitizer-mediated antimicrobial photodynamic therapy (PDT) appears to be a promising and innovative approach for treating multidrug resistant infection. In spite of encouraging reports of the use of antimicrobial PDT to inactivate MRSA in large in vitro studies, there are only few in vivo studies. Therefore, applying PDT in the clinic for MRSA infection is still a long way off. PMID:23555074

  8. 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.

  9. Methamphetamine use and methicillin-resistant Staphylococcus aureus skin infections.

    PubMed

    Cohen, Adam L; Shuler, Carrie; McAllister, Sigrid; Fosheim, Gregory E; Brown, Michael G; Abercrombie, Debra; Anderson, Karen; McDougal, Linda K; Drenzek, Cherie; Arnold, Katie; Jernigan, Daniel; Gorwitz, Rachel

    2007-11-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections and methamphetamine use are emerging public health problems. We conducted a case-control investigation to determine risk factors for MRSA skin and soft tissue infections (SSTIs) in residents of a largely rural southeastern community in the United States. Case-patients were persons >12 years old who had culturable SSTIs; controls had no SSTIs. Of 119 SSTIs identified, 81 (68.1%) were caused by MRSA. Methamphetamine use was reported in 9.9% of case-patients and 1.8% of controls. After we adjusted for age, sex, and race, patients with MRSA SSTIs were more likely than controls to have recently used methamphetamine (odds ratio 5.10, 95% confidence interval 1.55-16.79). MRSA caused most SSTIs in this population. Transmission of MRSA may be occurring among methamphetamine users in this community.

  10. Methamphetamine Use and Methicillin-Resistant Staphylococcus aureus Skin Infections

    PubMed Central

    Shuler, Carrie; McAllister, Sigrid; Fosheim, Gregory E.; Brown, Michael G.; Abercrombie, Debra; Anderson, Karen; McDougal, Linda K.; Drenzek, Cherie; Arnold, Katie; Jernigan, Daniel; Gorwitz, Rachel

    2007-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections and methamphetamine use are emerging public health problems. We conducted a case–control investigation to determine risk factors for MRSA skin and soft tissue infections (SSTIs) in residents of a largely rural southeastern community in the United States. Case-patients were persons >12 years old who had culturable SSTIs; controls had no SSTIs. Of 119 SSTIs identified, 81 (68.1%) were caused by MRSA. Methamphetamine use was reported in 9.9% of case-patients and 1.8% of controls. After we adjusted for age, sex, and race, patients with MRSA SSTIs were more likely than controls to have recently used methamphetamine (odds ratio 5.10, 95% confidence interval 1.55–16.79). MRSA caused most SSTIs in this population. Transmission of MRSA may be occurring among methamphetamine users in this community. PMID:18217555

  11. Methicillin-resistant Staphylococcus aureus adaptation to human keratinocytes.

    PubMed

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

    2015-04-21

    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. Human skin is a major site of staphylococcal infection, and keratinocytes actively participate in eradication of these pathogens. We demonstrate that methicillin-resistant Staphylococcus aureus (MRSA) is ingested by keratinocytes and activates caspase-1-mediated clearance through pyroptosis. Toxin-deficient MRSA mutants are selected within keratinocytes that fail to induce caspase-1 activity and keratinocyte-mediated clearance. These intracellular staphylococci induce autophagy that enhances their intracellular survival by diminishing

  12. Hyperimmunoglobulin E syndrome with persistent vertebral osteomyelitis due to methicillin-resistant Staphylococcus aureus

    PubMed Central

    Wong, San S.; Smith, Peter R.; Ayaz, Asim; Sepkowitz, Douglas

    2014-01-01

    We report a case of vertebral osteomyelitis due to methicillin-resistant Staphylococcus aureus (MRSA) with a slowly progressive, relatively asymptomatic course in a young woman with suspected hyperimmunoglobulin E syndrome (Job's syndrome). PMID:26839768

  13. 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.

  14. Prevalence of canine methicillin resistant Staphylococcus pseudintermedius in a veterinary diagnostic laboratory in Italy.

    PubMed

    De Lucia, M; Moodley, A; Latronico, F; Giordano, A; Caldin, M; Fondati, A; Guardabassi, L

    2011-12-01

    The overall prevalence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) was 2% (10/590) among 590 canine specimens submitted to an Italian veterinary diagnostic laboratory during a two-month period, and 21% (10/48) among Staphylococcus intermedius group (SIG) isolates. All methicillin-resistant strains exhibited additional resistance to fluoroquinolones, gentamicin, lincosamides, tetracyclines, and potentiated sulfonamides, belonged predominantly to spa type t02 and harboured SCCmec type II-III cassette.

  15. Key genetic elements and regulation systems in methicillin-resistant Staphylococcus aureus.

    PubMed

    Hao, Haihong; Dai, Menghong; Wang, Yulian; Huang, Lingli; Yuan, Zonghui

    2012-11-01

    Methicillin-resistant Staphylococcus aureus (MRSA), popularly known as a type of superbug, has been a serious challenge for animal and human health. S. aureus has developed methicillin resistance mainly by expression of β-lactamase and PBP2a, which is regulated by the blaZ-blaI-blaR1 and mecA-mecI-mecRI systems. Other genetic elements, including murE and femA, also participate in expression of methicillin resistance, but the mechanism remains unclear. The evolution of the staphylococcal cassette chromosome mec determines the epidemiological risk of MRSA. The plasmid-located gene cfr might contribute to multiresistance and transmission of MRSA. Some virulence factors, including Panton-Valentine leukocidin, phenol-soluble modulin, arginine catabolic mobile element and other toxin elements enhance the pathogenesis and fitness of MRSA. Two-component regulation systems (agr, saeRS and vraRS) are closely associated with pathogenesis and drug resistance of MRSA. The systematic exploration of key genetic elements and regulation systems involved in multidrug resistance/pathogenesis/transmission of MRSA is conclusively integrated into this review, providing fundamental information for the development of new antimicrobial agents and the establishment of reasonable antibiotic stewardship to reduce the risk of this superbug.

  16. Staphylococcus aureus: methicillin-susceptible S. aureus to methicillin-resistant S. aureus and vancomycin-resistant S. aureus.

    PubMed

    Rehm, Susan J; Tice, Alan

    2010-09-15

    The evolution of methicillin-resistant and vancomycin-resistant Staphylococcus aureus has demanded serious review of antimicrobial use and development of new agents and revised approaches to prevent and overcome drug resistance. Depending on local conditions and patient risk factors, empirical therapy of suspected S. aureus infection may require coverage of drug-resistant organisms with newer agents and novel antibiotic combinations. The question of treatment with inappropriate antibiotics raises grave concerns with regard to methicillin-resistant S. aureus selection, overgrowth, and increased virulence. Several strategies to reduce the nosocomial burden of resistance are suggested, including shortened hospital stays and outpatient parenteral antimicrobial therapy of the most serious infections.

  17. Outstanding Prevalence of Methicillin Resistant Staphylococcus aureus in Neonatal Omphalitis

    PubMed Central

    Sengupta, Mallika; Banerjee, Pritam; Guchhait, Partha

    2016-01-01

    Introduction Omphalitis is the infection of the umbilical cord stump, which can lead to septicaemia and significant neonatal morbidity and mortality. Very little data is available on the aetiology of neonatal omphalitis in India. Aim To identify the causative agents of omphalitis in neonates and determine the antimicrobial susceptibility patterns of the isolates. Materials and Methods A prospective study was conducted at ESI-PGIMSR and ESIC Medical College, Joka, a tertiary care teaching hospital in Eastern India for a period of four months (from 1st January 2016 to 30th April 2016). Neonates were screened for omphalitis on the basis of presence of pus and redness for inclusion. Clinical examination, Gram stain and culture of umbilical discharge, identification of organisms by biochemical tests and VITEK 2 Compact (bioMereiux Inc., France) was done. Antimicrobial susceptibility by Kirby Bauer disc diffusion method and E-strip agar diffusion method (for vancomycin and teicoplanin) were performed and interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guidelines version 2015. Results A total of 623 neonates were screened, among whom 21 (3.37%) were positive for our screening criteria for omphalitis. Cultures from the exudates of those cases yielded growth of Staphylococcus aureus in 19 (90.47%) samples, all of which were found to be methicillin resistant Staphylococcus aureus (MRSA). Resistance to erythromycin was seen among 36.82% isolates and inducible clindamycin resistance was seen among 31.57% isolates of Staphylococcus aureus. Conclusion MRSA can be the most common cause of omphalitis. However, this finding needs to be evaluated in larger prospective studies. PMID:27790440

  18. Heme Oxygenase-1 Deficiency Diminishes Methicillin-Resistant Staphylococcus aureus Clearance Due to Reduced TLR9 Expression in Pleural Mesothelial Cells

    PubMed Central

    Gahlot, Satindra; Nasreen, Najmunnisa; Johnson, Judith A.; Sahn, Steven A.; Mohammed, Kamal A.

    2017-01-01

    Methicillin Resistant Staphylococcus aureus (MRSA) cause pneumonia and empyema thoraces. TLR9 activation provides protection against bacterial infections and Heme oxygenase-1 (HO-1) is known to enhance host innate immunity against bacterial infections. However, it is still unclear whether HO-1 regulates TLR-9 expression in the pleura and modulates the host innate defenses during MRSA empyema. In order to determine if HO-1 regulates host innate immune functions via modulating TLR expression, in MRSA empyema, HO-1+/+ and HO-1-/- mouse pleural mesothelial cells (PMCs) were infected with MRSA (1:10, MOI) in the presence or absence of Cobalt Protoporphyrin (CoPP) and Zinc Protoporphyrin (ZnPP) or CORM-2 (a Carbon monoxide donor) and the expression of mTLR9 and mBD14 was assessed by RT-PCR. In vivo, HO-1+/+ and HO-1-/- mice were inoculated with MRSA (5x106 CFU) intra-pleurally and host bacterial load was measured by CFU, and TLR9 expression in the pleura was determined by histochemical-immunostaining. We noticed MRSA inducing differential expression of TLR9 in HO-1+/+ and HO-1 -/- PMCs. In MRSA infected HO-1+/+ PMCs, TLR1, TLR4, and TLR9 expression was several fold higher than MRSA infected HO-1-/- PMCs. Particularly TLR9 expression was very low in MRSA infected HO-1-/- PMCs both in vivo and in vitro. Bacterial clearance was significantly higher in HO-1+/+ PMCs than compared to HO-1-/- PMCs in vitro, and blocking TLR9 activation diminished MRSA clearance significantly. In addition, HO-1-/- mice were unable to clear the MRSA bacterial load in vivo. MRSA induced TLR9 and mBD14 expression was significantly high in HO-1+/+ PMCs and it was dependent on HO-1 activity. Our findings suggest that HO-1 by modulating TLR9 expression in PMCs promotes pleural innate immunity in MRSA empyema. PMID:28052108

  19. Mutation in the C-di-AMP cyclase dacA affects fitness and resistance of methicillin resistant Staphylococcus aureus.

    PubMed

    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.

  20. Detection of methicillin-resistant Staphylococcus aureus in Iberian pigs.

    PubMed

    Porrero, M C; Wassenaar, T M; Gómez-Barrero, S; García, M; Bárcena, C; Alvarez, J; Sáez-Llorente, J L; Fernández-Garayzábal, J F; Moreno, M A; Domínguez, L

    2012-04-01

    Iberian pigs are bred in Spain for the production of high-value dry-cured products, whose export volumes are increasing. Animals are typically reared outdoors, although indoor farming is becoming popular. We compared carriage of methicillin-resistant Staphylococcus aureus (MRSA) in Iberian pigs, raised indoors and outdoors, with intensively farmed Standard White pigs. From June 2007 to February 2008, 106 skin swabs were taken from Iberian pigs and 157 samples from SWP at slaughterhouses in Spain. We found that Iberian pigs carried MRSA, although with a significantly lower prevalence (30/106; 28%) than SWP (130/157; 83%). A higher prevalence of indoor Iberian pigs compared with animals reared under outdoor conditions was not significant; however, all but one positive indoor Iberian pig samples were detected from one slaughterhouse. Overall, 16 different spa types were identified, with t011 predominating in all three animal populations. A subset of isolates was characterized by MLST. Most of these belonged to ST398. MRSA isolates from Iberian pigs presented a higher susceptibility to antibiotics than those isolated from SWP. Despite limited contact with humans, pigs raised outdoors are colonized by an MRSA population that genetically overlaps with that of intensively farmed pigs, although antimicrobial resistance is lower. To our knowledge, this is the first detection of MRSA in food animals raised in free-range conditions. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

  1. New pharmacological treatments for methicillin-resistant Staphylococcus aureus infections.

    PubMed

    Burke, Stuart L; Rose, Warren E

    2014-03-01

    Despite available treatment options for methicillin-resistant Staphylococcus aureus (MRSA), the morbidity and mortality attributed to the diverse infection manifestations of this pathogen remain high. More anti-MRSA agents are needed as options for treatment of these infections. Ideally, these new agents would be rapidly bactericidal for bloodstream clearance in septic patients, have few toxicities, be active against MRSA in biofilms, be easy to administer, and have oral bioavailability. This review focuses on MRSA agents in Phase III trials or antibiotics currently in the market, which are being studied for new indications. For each agent, the antimicrobial potency against MRSA, pharmacokinetic and pharmacodynamic considerations and approved and potential new indications are presented. The role of novel combination therapies is also introduced. The new lipoglycopeptides oritavancin, telavancin and dalbavancin have the potential to make a large impact on the treatment of MRSA due to unique pharmacokinetic/pharmacodynamic properties and proposed dosing regimens. Other new agents (omadacycline and tedizolid) as well as revisited older agents (fosfomycin and fusidic acid) appear promising but require further study for their potential role. Combination therapy may improve outcomes in patients with high MRSA infection burden or when patient or pathogen factors predict a worse outcome with monotherapy.

  2. Evaluation of minocycline susceptibility of methicillin-resistant Staphylococcus pseudintermedius.

    PubMed

    Weese, J S; Sweetman, K; Edson, H; Rousseau, J

    2013-03-23

    Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an increasingly important cause of opportunistic infections in dogs and cats. Treatment options are often limited because of the high level of antimicrobial resistance. Doxycycline resistance is common, but variable mechanisms of doxycycline resistance exist, with some conferring resistance to doxycycline but not minocycline. However, there has been limited study of minocycline susceptibility in clinical MRSP isolates nor has the association of susceptibility and clonal complex been clearly established. The objective of this study was to evaluate the susceptibility of MRSP to tetracycline, doxycycline and minocycline, to determine the prevalence of tet(M) and tet(K) and to evaluate the impact of strain on minocycline susceptibility. One hundred seven MRSP isolates from dogs from Canada and the US were included; 79 from clinical infections and 28 from colonization sites. Thirty-nine (36%) isolates were susceptible to tetracycline, 41 (38%) to doxycycline and 70 (65%) to minocycline. Two main dru types, dt9a and dt11a, were present. When tetracycline or doxycycline resistant, dru type dt9a and related strains predominantly harboured tet(K) and were susceptible to minocycline. In contrast, dt11a and related strains tended to harbour tet(M), which confers resistance to all three tetracyclines. Minocycline might be a treatment option for some MRSP infections, even those that are doxycycline resistant; however, interpretive breakpoints may need to be re-assessed. Study of the pharmacokinetics and clinical efficacy of minocycline in dogs and cats is warranted.

  3. 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

  4. Investigational drugs to treat methicillin-resistant Staphylococcus aureus.

    PubMed

    Vuong, Cuong; Yeh, Anthony J; Cheung, Gordon Y C; Otto, Michael

    2016-01-01

    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, a situation that calls for continuing if not increased efforts to find novel strategies to combat MRSA infections. This review provides an overview of current investigational drugs and therapeutic antibodies against S. aureus in early clinical development (up to phase II clinical development). It includes a short description of the mechanism of action and a presentation of microbiological and clinical data. Increased recent antibiotic development efforts and results from pathogenesis research have led to several new antibiotics and therapies, such as anti-virulence 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.

  5. 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.

  6. 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

  7. Community-associated methicillin-resistant Staphylococcus aureus infection

    PubMed Central

    Loewen, Kassandra; Schreiber, Yoko; Kirlew, Mike; Bocking, Natalie; Kelly, Len

    2017-01-01

    Abstract Objective To provide information on the prevalence and treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections and the distinction between community-associated MRSA and health care–associated MRSA. Quality of evidence The MEDLINE and EMBASE databases were searched from 2005 to 2016. Epidemiologic studies were summarized and the relevant treatment literature was based on level I evidence. Main message The incidence of community-associated MRSA infection is rising. Certain populations, including indigenous Canadians and homeless populations, are particularly affected. Community-associated MRSA can be distinguished from health care–associated MRSA based on genetic, epidemiologic, or microbiological profiles. It retains susceptibility to some oral agents including trimethoprim-sulfamethoxazole, clindamycin, and tetracyclines. Community-associated MRSA typically presents as purulent skin and soft tissue infection, but invasive infection occurs and can lead to severe, complicated disease. Treatment choices and the need for empiric MRSA coverage are influenced by the type and severity of infection. Conclusion Community-associated MRSA is a common cause of skin and soft tissue infections and might be common in populations where overcrowding and limited access to clean water exist. PMID:28701438

  8. 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

  9. 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

  10. Methicillin-resistant Staphylococcus aureus in diabetic foot infections.

    PubMed

    Eleftheriadou, Ioanna; Tentolouris, Nicholas; Argiana, Vasiliki; Jude, Edward; Boulton, Andrew J

    2010-10-01

    Diabetic foot ulcers are often complicated by infection. Among pathogens, Staphylococcus aureus predominates. The prevalence of methicillin-resistant S. aureus (MRSA) in infected foot ulcers is 15-30% and there is an alarming trend for increase in many countries. There are also data that recognize new strains of MRSA that are resistant to vancomycin. The risk for MRSA isolation increases in the presence of osteomyelitis, nasal carriage of MRSA, prior use of antibacterials or hospitalization, larger ulcer size and longer duration of the ulcer. The need for amputation and surgical debridement increases in patients infected with MRSA. Infections of mild or moderate severity caused by community-acquired MRSA can be treated with cotrimoxazole (trimethoprim/sulfamethoxazole), doxycycline or clindamycin when susceptibility results are available, while severe community-acquired or hospital-acquired MRSA infections should be managed with glycopeptides, linezolide or daptomycin. Dalbavancin, tigecycline and ceftobiprole are newer promising antimicrobial agents active against MRSA that may also have a role in the treatment of foot infections if more data on their efficacy and safety become available.

  11. Fluoroquinolones and risk for methicillin-resistant Staphylococcus aureus, Canada.

    PubMed

    LeBlanc, Louiselle; Pépin, Jacques; Toulouse, Krystel; Ouellette, Marie-France; Coulombe, Marie-Andrée; Corriveau, Marie-Pier; Alary, Marie-Eve

    2006-09-01

    Receipt of fluoroquinolones was the predominant risk factor for Clostridium difficile-associated disease (CDAD) during an epidemic in Quebec, Canada. To determine the role of antimicrobial drugs in facilitating healthcare-associated methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection and to compare this role with their effects on methicillin-susceptible S. aureus infection and CDAD, we conducted a retrospective cohort study of patients in a Quebec hospital. For 7371 episodes of care, data were collected on risk factors, including receipt of antimicrobial drugs. Crude and adjusted hazard ratios (AHR) were calculated by Cox regression. Of 150 episodes of MRSA colonization and 23 of MRSA infection, fluoroquinolones were the only antimicrobials that increased risk for colonization (AHR 2.57, 95% confidence interval [CI] 1.84-3.60) and infection (AHR 2.49, 95% CI 1.02-6.07). Effect of antimicrobial drugs on MRSA colonization and infection was similar to effect on CDAD and should be considered when selecting antimicrobial drugs to treat common infections.

  12. Anthracimycin Activity Against Contemporary Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Hensler, Mary E.; Jang, Kyoung Hwa; Thienphrapa, Wdee; Vuong, Lisa; Tran, Dan N.; Soubih, Evaristus; Lin, Leo; Haste, Nina M.; Cunningham, Mark L.; Kwan, Bryan P.; Shaw, Karen Joy; Fenical, William; Nizet, Victor

    2014-01-01

    Anthracimycin is a recently discovered novel marine-derived compound with activity against Bacillus anthracis. We tested anthracimycin against an expanded panel of Staphylococcus aureus strains in vitro and in vivo. All strains of S. aureus tested, including methicillin-sensitive (MSSA), methicillin-resistant (MRSA), and vancomycin-resistant strains of S. aureus were sensitive to anthracimycin at minimum inhibitory concentrations (MIC) of < 0.25 mg/L. Although its post-antibiotic effects were minimal, anthracimycin exhibited potent and rapid bactericidal activity, with a > 4-log kill of USA300 MRSA within 3 hours at 5 times its MIC. At concentrations significantly below the MIC, anthracimycin slowed MRSA growth and potentiated the bactericidal activity of the human cathelicidin, LL-37. The bactericidal activity of anthracimycin was somewhat mitigated in the presence of 20% human serum, and the compound was minimally toxic to human cells, with an IC50 = 70 mg/L against human carcinoma cells. At concentrations near the MIC anthracimycin inhibited S. aureus nucleic acid synthesis as determined by optimized macromolecular synthesis methodology, with inhibition of DNA and RNA synthesis occurring in the absence of DNA intercalation. Anthracimycin at a single dose of 1 or 10 mg/kg was able to protect mice from MRSA-induced mortality in a murine peritonitis model of infection. Anthracimycin provides an interesting new scaffold for future development of a novel MRSA antibiotic. PMID:24736856

  13. Antibacterial Activity of THAM Trisphenylguanide against Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    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. PMID:24840307

  14. Oxacillin sensitization of methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus pseudintermedius by antisense peptide nucleic acids in vitro.

    PubMed

    Goh, Shan; Loeffler, Anette; Lloyd, David H; Nair, Sean P; Good, Liam

    2015-11-11

    Antibiotic resistance genes can be targeted by antisense agents, which can reduce their expression and thus restore cellular susceptibility to existing antibiotics. Antisense inhibitors can be gene and pathogen specific, or designed to inhibit a group of bacteria having conserved sequences within resistance genes. Here, we aimed to develop antisense peptide nucleic acids (PNAs) that could be used to effectively restore susceptibility to β-lactams in methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP). Antisense PNAs specific for conserved regions of the mobilisable gene mecA, and the growth essential gene, ftsZ, were designed. Clinical MRSA and MRSP strains of high oxacillin resistance were treated with PNAs and assayed for reduction in colony forming units on oxacillin plates, reduction in target gene mRNA levels, and cell size. Anti-mecA PNA at 7.5 and 2.5 μM reduced mecA mRNA in MRSA and MRSP (p < 0.05). At these PNA concentrations, 66 % of MRSA and 92 % of MRSP cells were killed by oxacillin (p < 0.01). Anti-ftsZ PNA at 7.5 and 2.5 μM reduced ftsZ mRNA in MRSA and MRSP, respectively (p ≤ 0.05). At these PNA concentrations, 86 % of MRSA cells and 95 % of MRSP cells were killed by oxacillin (p < 0.05). Anti-ftsZ PNAs resulted in swelling of bacterial cells. Scrambled PNA controls did not affect MRSA but sensitized MRSP moderately to oxacillin without affecting mRNA levels. The antisense PNAs effects observed provide in vitro proof of concept that this approach can be used to reverse β-lactam resistance in staphylococci. Further studies are warranted as clinical treatment alternatives are needed.

  15. Methicillin-Resistant Staphylococcus aureus in Wound Cultures Recovered from a Combat Support Hospital in Iraq

    DTIC Science & Technology

    2010-07-01

    in multidrug-resistant community-associated methicillin-resistant Staph - ylococcus aureus clone USA300. Clin Infect Dis. 2009;48:1483–1484. 47. Ruhe...Mark A. Co, PhD, Wade Aldous, PhD, and Duane R. Hospenthal, MD, PhD Background: Staphylococcus aureus infections complicate care of combat- related...injuries and can independently result in skin and soft-tissue infections during deployments or training. Community-associated methicillin-resistant S

  16. Management of community-associated methicillin-resistant Staphylococcus aureus skin abscesses in children

    PubMed Central

    Robinson, Joan L; Salvadori, Marina I

    2011-01-01

    Uncomplicated skin abscesses in previously well children are typically managed with drainage alone. An increasing percentage of such abscesses are due to methicillin-resistant Staphylococcus aureus infections. Although definitive data are lacking, drainage alone appears to be a reasonable strategy for methicillin-resistant S aureus skin abscesses, with antibiotics reserved for infants younger than three months of age, or for children who are systemically unwell, have underlying medical problems or have significant surrounding cellulitis. PMID:22294871

  17. 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

  18. Longitudinal study on methicillin-resistant Staphylococcus pseudintermedius in households.

    PubMed

    Laarhoven, Laura M; de Heus, Phebe; van Luijn, Jeanine; Duim, Birgitta; Wagenaar, Jaap A; van Duijkeren, Engeline

    2011-01-01

    Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an emerging pathogen in dogs and has been found in Europe, Asia and North America. To date most studies are one-point prevalence studies and therefore little is known about the dynamics of MRSP in dogs and their surrounding. In this longitudinal study MRSP colonization in dogs and the transmission of MRSP to humans, contact animals and the environment was investigated. Sixteen dogs with a recent clinical MRSP infection were included. The index dogs, contact animals, owners and environments were sampled once a month for six months. Samples taken from the nose, perineum and infection site (if present) of the index cases and contact animals, and the nares of the owners were cultured using pre-enrichment. Index cases were found positive for prolonged periods of time, in two cases during all six samplings. In five of the 12 households that were sampled during six months, the index case was intermittently found MRSP-positive. Contact animals and the environment were also found MRSP-positive, most often in combination with a MRSP-positive index dog. In four households positive environmental samples were found while no animals or humans were MRSP-positive, indicating survival of MRSP in the environment for prolonged periods of time. Genotyping revealed that generally similar or indistinguishable MRSP isolates were found in patients, contact animals and environmental samples within the same household. Within two households, however, genetically distinct MRSP isolates were found. These results show that veterinarians should stay alert with (former) MRSP patients, even after repeated MRSP-negative cultures or after the disappearance of the clinical infection. There is a considerable risk of transmission of MRSP to animals in close contact with MRSP patients. Humans were rarely MRSP-positive and never tested MRSP-positive more than once suggesting occasional contamination or rapid elimination of colonization of

  19. Characterization of pig-associated methicillin-resistant Staphylococcus aureus.

    PubMed

    Li, Jun; Jiang, Nansong; Ke, Yuebin; Feßler, Andrea T; Wang, Yang; Schwarz, Stefan; Wu, Congming

    2017-03-01

    Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) have been reported in various countries worldwide. However, although China is one of the biggest pig and pork producers, large-scale studies on pig-associated LA-MRSA from China are scarce. The aims of this study were to analyze 2420 non-duplicate samples collected from pigs at swine farms and slaughterhouses in different regions in China during 2014 for the prevalence of pig-associated MRSA and to determine the antimicrobial resistance pheno- and genotypes of the respective isolates. MRSA isolates were identified in 270 (11.2%) samples. The isolates were characterized by antimicrobial susceptibility testing, multilocus sequence typing (MLST), spa typing, pulsed-field gel electrophoresis (PFGE) and screening for resistance genes. All MRSA isolates belonged to the clonal complex 9 and spa type t899, but showed variable PFGE patterns. All isolates were non-susceptible to oxacillin, cefoxitin, clindamycin, chloramphenicol, florfenicol, ciprofloxacin, and valnemulin. High rates of resistance were also observed for tetracycline (99.6%), erythromycin (97.0%), quinupristin-dalfopristin (97.0%), and gentamicin (80.4%). Three linezolid-non-susceptible isolates containing the multi-resistance gene cfr and nine rifampicin-non-susceptible isolates with mutations in rpoB were detected. Resistance to β-lactams was exclusively associated with mecA, while phenicol resistance was mainly attributable to fexA, except in the three cfr-positive isolates. The pleuromutilin-lincosamide-streptogramin A resistance gene lsa(E) was identified in all MRSA isolates, and no other pleuromutilin resistance genes, except cfr in three isolates, were detected. Pigs are the most important hosts of LA-MRSA in China. Screening for pig-associated MRSA is necessary to monitor changes in epidemiology and characteristics of these important pathogens. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Methicillin-resistant Staphylococcus aureus in England and Wales.

    PubMed

    Marples, R R; Reith, S

    1992-02-28

    Methicillin-resistant Staphylococcus aureus (MRSA) were detected soon after the introduction of methicillin in 1960, and reports of their isolation increased up to 1971. Changes in antibiotic usage were associated with a fall and then, in the early 1980s, a further rise in the number of reports. This article reviews the various surveys that have been conducted to establish the frequency, distribution and strain varieties of MRSA. The first strain to be recognised as epidemic (ie, affecting more than one hospital), was defined by phage typing and antibiogram, confirmed with molecular typing, and designated EMRSA-1. It was first detected in 1981 and became progressively more widespread until it began to decline in 1987. Only three health regions reported this strain in the first quarter of 1991. EMRSA-2 has remained restricted to the South East and South West Thames regions. EMRSA-3 appeared in the South East Thames region in 1987 and has since spread, being reported from eight health regions in the first quarter of 1991. At least 11 other strains of MRSA affecting more than one hospital have been detected and ten endemic strains (restricted to single hospitals) have been identified. Imported strains of MRSA, often introduced following the repatriation of road traffic accident victims, may include strains with epidemic potential and local spread has followed importation in at least two incidents. Continued surveillance of epidemic MRSA strains and the search for simple and widely applicable markers, such as unusual antibiotic resistance patterns or biochemical features, are needed for the prompt application of control measures.

  1. Methicillin-resistant Staphylococcus aureus colonization among medical residents

    PubMed Central

    Trépanier, Pascale; Tremblay, Claude; Ruest, Annie

    2013-01-01

    BACKGROUND: Medical residents may be at risk of becoming colonized by methicillin-resistant Staphylococcus aureus (MRSA) during their training. The occupational risk of this specific population is unknown. Furthermore, there are no data regarding MRSA colonization among health care professionals in Quebec. OBJECTIVE: To determine the MRSA colonization rate in Laval University (Quebec City, Quebec) medical residents and compare it with the MRSA colonization rate of a control group. METHODS: A controlled cross-sectional study of MRSA prevalence among medical residents of Laval University was performed. The control group consisted of Laval University undergraduate medical students without previous clinical rotations in their curriculum. After informed consent was obtained, participants were screened for MRSA with a nasal swab in both anterior nares. They also completed a questionnaire regarding relevant risk factors and demographic data. RESULTS: A total of 250 residents of all residency levels from medical and surgical specialties and 247 controls were recruited between February and April 2010. One case of MRSA colonization was detected among the residents and none in the control group (prevalence of 0.4% versus 0.0%; P=1.00). DISCUSSION: MRSA nasal carriage was very low among Laval University residents. This may reflect the decreasing rate of health care-associated MRSA in Quebec City. Young age and good health may also explain this low risk. The strict infection control policies for MRSA patients (including cohorting, use of gloves, gown and patient-dedicated equipment) may also contribute to prevent MRSA transmission. CONCLUSIONS: Medical residents in Quebec City appeared to be at very low risk of contracting MRSA through professional activities. PMID:24421816

  2. Methicillin-resistant Staphylococcus aureus (MRSA) pediatric tympanostomy tube otorrhea.

    PubMed

    Cheng, Jeffrey; Javia, Luv

    2012-12-01

    To describe our experience and clinical outcomes with the management of pediatric tympanostomy tube otorrhea secondary to methicillin-resistant Staphylococcus aureus (MRSA). Retrospective review of pediatric patients (age <18) diagnosed with culture-positive MRSA tympanostomy tube otorrhea. MRSA positive ear cultures in the presence of tympanostomy tubes were identified in 41 patients (6.3%). The average age was 2.9 years old. In all cases, culture results indicated sensitivity to trimethoprim/sulfamethoxazole and gentamicin; resistance to fluoroquinolones and clindamycin occurred in 87.8% and 61.0% of cases, respectively. Fluoroquinolone and sulfacetamide ototopical medications were found to be associated with successful otorrhea resolution (p=0.005 and 0.009, respectively). Adjunctive therapy with oral antibiotics, bactrim and clindamycin (p=0.172 and 0.877, respectively), did not improve resolution rates with medical treatment. Tympanostomy tube removal was more successful than medical therapy alone (p<0.0001). Appropriately treated recurrent or recalcitrant tympanostomy tube-related otorrhea should raise the suspicion for MRSA-related tympanostomy tube otorrhea. Fluoroquinolone ototopical medication should be considered for initial therapy. Sulfacetamide ototopical medication can be considered for failures. The adjunctive use of oral antibiotics, bactrim and clindamycin, and aminoglycoside ototopical medications did not improve clinical outcomes for medical therapy alone. We believe that some consideration be given to removal of the tympanostomy tube with or without replacement, after an initial treatment period with fluoroquinolone and/or sulfacetamide otopical medications. Our findings seem to suggest an improved rate with tympanostomy tube removal over medical therapy alone (p<0.0001). No standard management guidelines currently exist. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Surgical Site Infection by Methicillin Resistant Staphylococcus aureus- on Decline?

    PubMed

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

    2016-09-01

    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. To determine the prevalence of SSI caused by MRSA and the antibiotic sensitivity pattern of MRSA. 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. 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 group above 75 years (15.63%). The MRSA strains

  4. 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

  5. Methicillin resistance of Staphylococcus species among health care and nonhealth care workers undergoing cataract surgery

    PubMed Central

    Olson, Randall; Donnenfeld, Eric; Bucci, Frank A; Price, Francis W; Raizman, Michael; Solomon, Kerry; Devgan, Uday; Trattler, William; Dell, Steven; Wallace, R Bruce; Callegan, Michelle; Brown, Heather; McDonnell, Peter J; Conway, Taryn; Schiffman, Rhett M; Hollander, David A

    2010-01-01

    Purpose: The purpose of this study is to characterize the bacterial flora of the ocular and periocular surface in cataract surgery patients and to determine the prevalence of methicillin resistance among staphylococcal isolates obtained from health care workers (HCWs) and non-HCWs. Methods: In this prospective, multicenter, case series study, eyelid and conjunctival cultures were obtained from the nonoperative eye of 399 consecutive cataract patients on the day of surgery prior to application of topical anesthetics, antibiotics, or antiseptics. Speciation and susceptibility testing were performed at the Dean A. McGee Eye Institute. Logistic regression was utilized to evaluate whether any factors were significant in predicting the presence of methicillin-resistant staphylococcal isolates. Results: Staphylococcus epidermidis (62.9%), followed by S. aureus (14.0%), was the most frequently isolated organism. Methicillin-resistant S. epidermidis accounted for 47.1% (178/378) of S. epidermidis isolates, and methicillin-resistant S. aureus accounted for 29.5% (26/88) of S. aureus isolates. Methicillin-resistant staphylococcal isolates were found in 157 of 399 (39.3%) patients, the majority (89.2%) of whom were non-HCWs. The likelihood of being colonized with methicillin-resistant organisms increased with age (odds ratio [OR], 1.27; 95% confidence interval [CI]: 1.02–1.58; P = 0.04) but decreased with diabetes (OR, 0.51; 95% CI: 0.29–0.89; P = 0.02). Being a HCW (OR, 1.25; 95% CI: 0.61–2.58; P = 0.54) was not a risk factor for colonization with methicillin-resistant organisms. Conclusion: Patients without exposure to health care environments are as likely as HCWs to be colonized with methicillin-resistant organisms. Increasing methicillin resistance with age may partially explain the increased risk of endophthalmitis reported with older age. PMID:21191448

  6. Detection of methicillin resistance and slime factor production of Staphylococcus aureus in bovine mastitis.

    PubMed

    Ciftci, Alper; Findik, Arzu; Onuk, Ertan Emek; Savasan, Serap

    2009-04-01

    This study aimed to detect methicillin resistant and slime producing Staphylococcus aureus in cases of bovine mastitis. A triplex PCR was optimized targetting 16S rRNA, nuc and mecA genes for detection of Staphylococcus species, S. aureus and methicillin resistance, respectively. Furthermore, for detection of slime producing strains, a PCR assay targetting icaA and icaD genes was performed. In this study, 59 strains were detected as S. aureus by both conventional tests and PCR, and 13 of them were found to be methicillin resistant and 4 (30.7%) were positive for mecA gene. Although 22 of 59 (37.2%) S. aureus isolates were slime-producing in Congo Red Agar, in PCR analysis only 15 were positive for both icaA and icaD genes. Sixteen and 38 out of 59 strains were positive for icaA and icaD gene, respectively. Only 2 of 59 strains were positive for both methicillin resistance and slime producing, phenotypically, suggesting lack of correlation between methicillin resistance and slime production in these isolates. In conclusion, the optimized triplex PCR in this study was useful for rapid and reliable detection of methicillin resistant S. aureus. Furthermore, only PCR targetting icaA and icaD may not sufficient to detect slime production and further studies targetting other ica genes should be conducted for accurate evaluation of slime production characters of S. aureus strains.

  7. Detection of methicillin resistance and slime factor production of Staphylococcus aureus in bovine mastitis

    PubMed Central

    Ciftci, Alper; Findik, Arzu; Onuk, Ertan Emek; Savasan, Serap

    2009-01-01

    This study aimed to detect methicillin resistant and slime producing Staphylococcus aureus in cases of bovine mastitis. A triplex PCR was optimized targetting 16S rRNA, nuc and mecA genes for detection of Staphylococcus species, S. aureus and methicillin resistance, respectively. Furthermore, for detection of slime producing strains, a PCR assay targetting icaA and icaD genes was performed. In this study, 59 strains were detected as S. aureus by both conventional tests and PCR, and 13 of them were found to be methicillin resistant and 4 (30.7%) were positive for mecA gene. Although 22 of 59 (37.2%) S. aureus isolates were slime-producing in Congo Red Agar, in PCR analysis only 15 were positive for both icaA and icaD genes. Sixteen and 38 out of 59 strains were positive for icaA and icaD gene, respectively. Only 2 of 59 strains were positive for both methicillin resistance and slime producing, phenotypically, suggesting lack of correlation between methicillin resistance and slime production in these isolates. In conclusion, the optimized triplex PCR in this study was useful for rapid and reliable detection of methicillin resistant S. aureus. Furthermore, only PCR targetting icaA and icaD may not sufficient to detect slime production and further studies targetting other ica genes should be conducted for accurate evaluation of slime production characters of S. aureus strains. PMID:24031354

  8. Community-acquired methicillin-resistant Staphylococcus aureus: an emerging cause of acute bacterial parotitis.

    PubMed

    Nicolasora, Nelson P; Zacharek, Mark A; Malani, Anurag N

    2009-02-01

    Staphylococcus aureus has long been recognized as a cause of acute bacterial parotitis. A case of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) parotitis is presented, highlighting the emergence of this increasingly important pathogen to cause a wide variety of infections. Also reviewed are the salient clinical and microbiologic features of this novel infection.

  9. 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.

  10. 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

  11. Methicillin-resistant Staphylococcus non-aureus infection in an irradiated rhesus macaque (Macaca mulatta).

    PubMed

    Kolappaswamy, Krishnan; Shipley, Steven T; Tatarov, Ivan I; DeTolla, Louis J

    2008-05-01

    We describe a case of methicillin-resistant Staphylococcus non-aureus infection in a rhesus macaque (Macaca mulatta). The nonhuman primate described was part of a research project that involved whole-body gamma irradiation and subsequently developed acute generalized dermatitis with skin dryness, peeling, and erythema around the eyes. After initial evaluation, which included microbiologic culture and 6 d of medical treatment, the animal was euthanized due to concern regarding a possible outbreak of infectious or zoonotic disease. On the basis of skin culture, diagnosis of methicillin-resistant Staphylococcus non-aureus was confirmed. This report underscores the importance of the occupational risk of methicillin-resistant Staphylococcus non-aureus to research and animal care staff in a research animal facility setting.

  12. Eradication and Sensitization of Methicillin Resistant Staphylococcus aureus to Methicillin with Bioactive Extracts of Berry Pomace

    PubMed Central

    Salaheen, Serajus; Peng, Mengfei; Joo, Jungsoo; Teramoto, Hironori; Biswas, Debabrata

    2017-01-01

    The therapeutic roles of phenolic blueberry (Vaccinium corymbosum) and blackberry (Rubus fruticosus) pomace (commercial byproduct) extracts (BPE) and their mechanism of actions were evaluated against methicillin resistant Staphylococcus aureus (MRSA). Five major phenolic acids of BPE, e.g., protocatechuic, p. coumaric, vanillic, caffeic, and gallic acids, as well as crude BPE completely inhibited the growth of vegetative MRSA in vitro while BPE+methicillin significantly reduced MRSA biofilm formation on plastic surface. In addition, BPE restored the effectiveness of methicillin against MRSA by down-regulating the expression of methicillin resistance (mecA) and efflux pump (norA, norB, norC, mdeA, sdrM, and sepA) genes. Antibiogram with broth microdilution method showed that MIC of methicillin reduced from 512 μg/mL to 4 μg/mL when combined with only 200 μg Gallic Acid Equivalent (GAE)/mL of BPE. Significant reduction in MRSA adherence to and invasion into human skin keratinocyte Hek001 cells were also noticed in the presence of BPE. BPE induced anti-apoptosis and anti-autophagy pathways through overexpression of Bcl-2 gene and down-regulation of TRADD and Bax genes (inducers of apoptosis pathway) in Hek001 cells. In summary, novel and sustainable prophylactic therapy can be developed with BPE in combination with currently available antibiotics, especially methicillin, against skin and soft tissue infections with MRSA. PMID:28270804

  13. Isolation of methicillin-resistant Staphylococcus spp. from ready-to-eat fish products.

    PubMed

    Sergelidis, D; Abrahim, A; Papadopoulos, T; Soultos, N; Martziou, E; Koulourida, V; Govaris, A; Pexara, A; Zdragas, A; Papa, A

    2014-11-01

    A hundred samples from ready-to-eat (RTE) fish products were examined for the presence and antimicrobial susceptibility of Staphylococcus spp. Staphylococci were isolated from 43% of these samples (n = 100). The identified species in the samples were Staphylococcus aureus (7%), Staphylococcus epidermidis (13%), Staphylococcus xylosus (12%), Staphylococcus sciuri (4%), Staphylococcus warneri (3%), Staphylococcus saprophyticus (2%), Staphylococcus schleiferi (1%) and Staphylococcus auricularis (1%). Two Staph. aureus (MRSA) isolates, three Staph. epidermidis (MRSE), five Staph. xylosus, four Staph. sciuri, one Staph. schleiferi and one Staph. saprophyticus isolates were resistant to oxacillin and all of them carried the mecA gene. The two MRSA isolates belonged to the spa types t316 (ST359) and t548 (ST5) and none of them was able to produce enterotoxins. Pulsed field gel electrophoresis for Staph. aureus and Staph. epidermidis isolates revealed 6 and 11 distinct PFGE types, respectively, reflecting diversity. The presence of methicillin-resistant staphylococci, especially MRSA and MRSE, in RTE fish products may constitute a potential health risk for consumers. This study provides the first data on the occurrence of methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci in salted and smoked fish products in Greece. These results are important and useful for Staphylococcus spp. risk assessment and management programmes for ready-to-eat fish products. © 2014 The Society for Applied Microbiology.

  14. A Model for Evaluating Topical Antimicrobial Efficacy against Methicillin-Resistant Staphylococcus aureus Biofilms in Superficial Murine Wounds

    PubMed Central

    Renick, Paul J.; Tetens, Shannon P.; Carson, Dennis L.

    2012-01-01

    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. PMID:22644024

  15. 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

  16. 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

  17. Cluster of infections caused by methicillin-resistant Staphylococcus pseudintermedius in humans in a tertiary hospital.

    PubMed

    Starlander, Gustaf; Börjesson, Stefan; Grönlund-Andersson, Ulrika; Tellgren-Roth, Christian; Melhus, Asa

    2014-08-01

    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.

  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.

  19. 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

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

    PubMed

    Riley, Matthew C; Perreten, Vincent; Bemis, David A; Kania, Stephen A

    2016-10-20

    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.

  1. Community-acquired methicillin-resistant Staphylococcus aureus among military recruits.

    PubMed

    Zinderman, Craig E; Conner, Byron; Malakooti, Mark A; LaMar, James E; Armstrong, Adam; Bohnker, Bruce K

    2004-05-01

    We report an outbreak of 235 community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections among military recruits. In this unique environment, the close contact between recruits and the physical demands of training may have contributed to the spread of MRSA. Control measures included improved hygiene and aggressive clinical treatment.

  2. Molecular Characterization of Methicillin-Resistant Staphylococcus aureus Causing Fatal Purulent Pericarditis

    PubMed Central

    Kumar, Vasudevan Anil; Nair, Nisha; Thachathodiyl, Rajesh; Nandakumar, Aswathy; Dinesh, Kavitha R; Thatcher, Eileen; Karim, Shamsul; Biswas, Raja

    2013-01-01

    Though pericardial disease is common in patients with renal disease, purulent pericarditis is very rare. We report a fatal case of purulent pericarditis and sepsis due to methicillin-resistant Staphylococcus aureus in a 78-year-old male with systemic hypertension and renal disease along with the molecular characterization of its resistant mechanism. PMID:24701111

  3. Disulfiram inhibits the in vitro growth of methicillin-resistant staphylococcus aureus.

    PubMed Central

    Phillips, M; Malloy, G; Nedunchezian, D; Lukrec, A; Howard, R G

    1991-01-01

    Several antibiotics have disulfiram-like effects; we evaluated disulfiram for its antibiotic-like effects. Disulfiram inhibited the in vitro growth of methicillin-resistant Staphylococcus aureus, with an MIC of 1.33 micrograms/ml, but was not effective against members of the family Enterobacteriaceae or Pseudomonas species. PMID:2069390

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

    USDA-ARS?s Scientific Manuscript database

    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...

  5. Methicillin-Resistant Staphylococcus aureus ST398 from Human Patients, Upper Austria

    PubMed Central

    Metz-Gercek, Sigrid; Mittermayer, Helmut

    2009-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) clonal type ST398 is usually associated with animals. We examined 1,098 confirmed MRSA samples from human patients and found that 21 were MRSA ST398. Most (16) patients were farmers. Increasing prevalence from 1.3% (2006) to 2.5% (2008) shows emergence of MRSA ST398 in humans in Austria. PMID:19402964

  6. Methicillin-Resistant Staphylococcus aureus ST398 from human patients, upper Austria.

    PubMed

    Krziwanek, Karina; Metz-Gercek, Sigrid; Mittermayer, Helmut

    2009-05-01

    Methicillin-resistant Staphylococcus aureus (MRSA) clonal type ST398 is usually associated with animals. We examined 1,098 confirmed MRSA samples from human patients and found that 21 were MRSA ST398. Most (16) patients were farmers. Increasing prevalence from 1.3% (2006) to 2.5% (2008) shows emergence of MRSA ST398 in humans in Austria.

  7. 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

  8. Draft Genome Sequence of Strain CBD-635, a Methicillin-Resistant Staphylococcus aureus USA100 Isolate.

    PubMed

    Carroll, Ronan K; Burda, Whittney N; Roberts, Jill C; Peak, Kealy K; Cannons, Andrew C; Shaw, Lindsey N

    2013-07-11

    We present the draft genome sequence of methicillin-resistant Staphylococcus aureus strain CBD-635, from the USA100 lineage. This is a sepsis isolate obtained from Tampa General Hospital. This strain is spa type t003 and multilocus sequence typing (MLST) type ST5, and it has been used by our group in the study of novel antimicrobial chemotherapeutics.

  9. Optimal Surveillance Culture Sites for Detection of Methicillin-Resistant Staphylococcus aureus in Newborns▿

    PubMed Central

    Rosenthal, Alana; White, Diane; Churilla, Sheila; Brodie, Sandra; Katz, Kevin C.

    2006-01-01

    We describe two outbreaks among newborns, one caused by community-associated methicillin-resistant Staphylococcus aureus (MRSA) and the other by hospital-associated MRSA. The umbilicus, rectum, and nares were tested for colonization. We found that no single body site had optimal sensitivity when tested alone. The combination of umbilical and nasal swabs achieved a sensitivity of >90%. PMID:16957041

  10. 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…

  11. 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…

  12. Livestock-associated Methicillin-Resistant Staphylococcus aureus in Humans, Europe

    PubMed Central

    Monnet, Dominique L.; Voss, Andreas; Krziwanek, Karina; Allerberger, Franz; Struelens, Marc; Zemlickova, Helena; Skov, Robert L.; Vuopio-Varkila, Jaana; Cuny, Christiane; Friedrich, Alexander W.; Spiliopoulou, Iris; Pászti, Judit; Hardardottir, Hjordis; Rossney, Angela; Pan, Angelo; Pantosti, Annalisa; Borg, Michael; Grundmann, Hajo; Mueller-Premru, Manica; Olsson-Liljequist, Barbro; Widmer, Andreas; Harbarth, Stephan; Schweiger, Alexander; Unal, Serhat; Kluytmans, Jan A.J.W.

    2011-01-01

    To estimate the proportion of methicillin-resistant Staphylococcus aureus (MRSA) isolates from humans that were sequence type (ST) 398, we surveyed 24 laboratories in 17 countries in Europe in 2007. Livestock-associated MRSA ST398 accounted for only a small proportion of MRSA isolates from humans; most were from the Netherlands, Belgium, Denmark, and Austria. PMID:21392444

  13. Methicillin-resistant Staphylococcus aureus in a beauty salon, the Netherlands.

    PubMed

    Huijsdens, Xander W; Janssen, Maria; Renders, Nicole H M; Leenders, Alexander; van Wijk, Paul; van Santen Verheuvel, Marga G; van Driel, Jolanda Koel; Morroy, Gabriella

    2008-11-01

    An outbreak of community-associated USA300 methicillin-resistant Staphylococcus aureus occurred in a beautician and 2 of her customers. Eight other persons, who were either infected (n = 5) or colonized (n = 3), were linked to this outbreak, including a family member, a household contact, and partners of customers.

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  16. 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

  17. 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

  18. Current knowledge about and recommendations for ocular methicillin-resistant Staphylococcus aureus.

    PubMed

    Mah, Francis S; Davidson, Richard; Holland, Edward J; Hovanesian, John; John, Thomas; Kanellopoulos, John; Shamie, Neda; Starr, Christopher; Vroman, David; Kim, Terry

    2014-11-01

    Staphylococcus aureus is the most important and common pathogen that infects patients following cataract surgery, laser in situ keratomileusis, and photorefractive keratectomy. It is reported to be the second most common pathogen causing bacterial keratitis around the world. Of special concern are increasing reports of postoperative methicillin-resistant S aureus (MRSA) infection. For example, MRSA wound infections have been reported with clear corneal phacoemulsification wounds, penetrating keratoplasty, lamellar keratoplasty, and following ex vivo epithelial transplantation associated with amniotic membrane grafts. These and other data suggest that MRSA has become increasingly prevalent worldwide. In this article, we review the current medical literature and describe the current challenge of ocular MRSA infections. Recommendations are made based on an evidence-based review to identify, treat, and possibly reduce the overall problem of this organism. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  19. 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

  20. Nosocomial keratitis caused by methicillin-resistant Staphylococcus aureus: case report and preventative measures.

    PubMed

    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.

  1. [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.

  2. Presence of Methicillin Resistant Staphylococcus aureus (MRSA) in sewage treatment plant.

    PubMed

    Boopathy, Raj

    2017-02-23

    The presence of antibiotic resistant bacteria and antibiotic resistance genes in rural sewage treatment plants are not well reported in the literature. The aim of the present study was to study the frequency occurrence of Methicillin Resistant Staphylococcus aureus (MRSA) in a rural sewage treatment plant. This study was conducted using raw sewage as well as treated sewage from a small town sewage treatment plant in rural southeast Louisiana of USA. Results showed the presence of MRSA consistently in both raw and treated sewage. The presence of mecA gene responsible for methicillin resistance was confirmed in the raw and treated sewage water samples.

  3. Community-acquired methicillin-resistant Staphylococcus aureus: an ongoing challenge for WOC nursing.

    PubMed

    Price, Molly

    2010-01-01

    Infection is a common complication of chronic wounds that delays healing. Community-acquired methicillin-resistant Staphylococcus aureus has emerged as a common pathogen and major impediment to healing affected chronic wounds. Community-acquired methicillin-resistant S aureus is virulent, highly communicable, and difficult to eradicate. Treatment options include incision and drainage, debridement, and systemic antimicrobials. Early aggressive wound management and appropriate antibiotic therapy are considered essential to successful treatment. Facility-specific protocols should be developed to minimize the spread of this organism to the general population, with particular attention focused on protecting patients burdened with chronic wounds. This article reviews current knowledge of community-acquired methicillin-resistant S aureus, focusing on its impact on persons with chronic wounds.

  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. Evaluation for a Novel Methicillin Resistance (mecC) Homologue in Methicillin-Resistant Staphylococcus aureus Isolates Obtained from Injured Military Personnel

    PubMed Central

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

    2013-01-01

    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. PMID:23784136

  6. Zinc resistance within swine associated methicillin resistant Staphylococcus aureus (MRSA) isolates in the USA is associated with MLST lineage

    USDA-ARS?s Scientific Manuscript database

    Zinc resistance in livestock-associated methicillin resistant Staphylococcus aureus (LA-MRSA) is mediated by the czrC gene co-located with the mecA gene, encoding methicillin resistance, on the type V SCCmec element. Since the czrC gene and the mecA gene are co-located on the SCCmec element, it has ...

  7. 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.

  8. Longitudinal Characterization of Acinetobacter baumannii-calcoaceticus Complex, Klebsiella pneumoniae, and Methicillin-Resistant Staphylococcus aureus Colonizing and Infecting Combat Casualties

    DTIC Science & Technology

    2012-01-01

    Brief report Longitudinal characterization of Acinetobacter baumannii-calcoaceticus complex, Klebsiella pneumoniae , and methicillin-resistant...resistant Acinetobacter baumannii-calcoaceticus complex Klebsiella pneumoniae Methicillin-resistant Staphylococcus aureus MRSA Drug-resistant...Acinetobacter baumannii-calcoaceticus complex, Klebsiella pneumoniae , and methicillin- resistant Staphylococcus aureus colonize and infect combat casualties

  9. Annual Surveillance Summary: Methicillin Resistant Staphylococcus aureus (MRSA) Infections in the Military Health System (MHS), 2016

    DTIC Science & Technology

    2017-06-30

    Staphylococcus aureus (MRSA) incidence and prevalence among all beneficiaries seeking care within the Military Health System (MHS). This report...Comparison of community- and health care -associated methicillin-resistant Staphylococcus aureus infection. JAMA. 2003;290(22):2976-84. 10. Patel...community‐associated CHCS  Composite  Health   Care  System CO  community‐onset CTS  Contingency Tracking System CY  calendar year DMDC  Defense Manpower Data

  10. 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

  11. 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

  12. Introduction of rapid methicillin-resistant Staphylococcus aureus polymerase chain reaction testing and antibiotic selection among hospitalized patients with purulent skin infections.

    PubMed

    Terp, Sophie; Krishnadasan, Anusha; Bowen, William; Joo, Julianne; Furoy, Daniel; Chan, Joseph; Moran, Gregory; Talan, David

    2014-04-01

    Introduction of a rapid methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction assay, with physician education and pharmacist guidance, did not significantly reduce excessive empiric prescription of MRSA-active antibiotics despite the test's accuracy and potential to substantially reduce inappropriate antibiotic use.

  13. 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.

  14. Methicillin-resistant Staphylococcus aureus (MRSA) in a tertiary surgical and trauma hospital in Benghazi, Libya.

    PubMed

    Buzaid, Najat; Elzouki, Abdel-Naser; Taher, Ibrahim; Ghenghesh, Khalifa Sifaw

    2011-10-13

    Methicillin resistant Staphylococcus aureus (MRSA) is a multidrug resistant organism that threatens the continued effectiveness of antibiotics worldwide and causes a threat almost exclusively in hospitals and long-term care settings. This study investigated the prevalence of MRSA strains and their sensitivity patterns against various antibiotics used for treating hospitalized patients in a major tertiary surgical hospital in Benghazi, Libya. We investigated 200 non-duplicate S. aureus strains isolated from different clinical specimens submitted to the Microbiology Laboratory at Aljala Surgical and Trauma Hospital, Benghazi, Libya from April to July 2007. Isolates were tested for methicillin resistance by the oxacillin disc-diffusion assay according to Clinical and Laboratory Standards Institute guidelines. MRSA strains were tested for antimicrobial resistance (i.e., vancomycin, ciprofloxacin, erythromycin, chloramphenicol and fusidic acid) using commercial discs. Information on patient demographics and clinical disease was also collected. Of the isolates examined 31% (62/200) were MRSA. No significant differences were observed in the prevalence of MRSA among S. aureus from females or males or from different age groups. Most MRSA were isolated from burns and surgical wound infections. Antibiotic resistance patterns of 62 patients with MRSA to vancomycin, ciprofloxacin, fusidic acid, chloramphenicol and erythromycin were 17.7%, 33.9%, 41.9%, 38.7% and 46.8% of cases, respectively. MRSA prevalence in our hospital was high and this may be the case for other hospitals in Libya. A sound surveillance program of nosocomial infections is urgently needed to reduce the incidence of infections due to MRSA and other antimicrobial-resistant pathogens in Libyan hospitals.

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  17. Twenty-Five Year Epidemiology of Invasive Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates Recovered at a Burn Center

    DTIC Science & Technology

    2009-01-01

    Twenty-five year epidemiology of invasive methicillin- resistant Staphylococcus aureus (MRSA) isolates recovered at a burn center§ Clinton K. Murray...history: Accepted 12 February 2009 Keywords: Burn center Epidemiology Methicillin-resistant Staphylococcus aureus Antimicrobial susceptibility a b s t r...invasive MRSA isolates over 25 years at a single burn unit. Isolates were tested by pulsed-field gel electrophoresis (PFGE), broth microdilution

  18. Novel methicillin-resistant coagulase-negative Staphylococcus clone isolated from patients with haematological diseases at the Blood Bank Centre of Amazon, Brazil

    PubMed Central

    Ferreira, Cristina Motta; Naveca, Felipe Gomes; Ferreira, William Antunes; de Oliveira, Cíntia Mara Costa; Barbosa, Maria das Graças Vale

    2013-01-01

    Methicillin-resistant Staphylococcus remains a severe public health problem worldwide. This research was intended to identify the presence of methicillin-resistant coagulase-negative staphylococci clones and their staphylococcal cassette chromosome mec (SCCmec)-type isolate from patients with haematologic diseases presenting bacterial infections who were treated at the Blood Bank of the state of Amazonas in Brazil. Phenotypic and genotypic tests, such as SCCmec types and multilocus sequence typing (MLST), were developed to detect and characterise methicillin-resistant isolates. A total of 26 Gram-positive bacteria were isolated, such as: Staphylococcus epidermidis (8/27), Staphylococcus intermedius (4/27) and Staphylococcus aureus (4/27). Ten methicillin-resistant staphylococcal isolates were identified. MLST revealed three different sequence types: S. aureus ST243, S. epidermidis ST2 and a new clone of S. epidermidis, ST365. These findings reinforce the potential of dissemination presented by multi-resistant Staphylococcus and they suggest the introduction of monitoring actions to reduce the spread of pathogenic clonal lineages of S. aureus and S. epidermidis to avoid hospital infections and mortality risks. PMID:23579805

  19. Recommendations for Methicillin-Resistant Staphylococcus aureus Prevention in Adult ICUs: A Cost-Effectiveness Analysis.

    PubMed

    Whittington, Melanie D; Atherly, Adam J; Curtis, Donna J; Lindrooth, Richard C; Bradley, Cathy J; Campbell, Jonathan D

    2017-08-01

    Patients in the ICU are at the greatest risk of contracting healthcare-associated infections like methicillin-resistant Staphylococcus aureus. This study calculates the cost-effectiveness of methicillin-resistant S aureus prevention strategies and recommends specific strategies based on screening test implementation. A cost-effectiveness analysis using a Markov model from the hospital perspective was conducted to determine if the implementation costs of methicillin-resistant S aureus prevention strategies are justified by associated reductions in methicillin-resistant S aureus infections and improvements in quality-adjusted life years. Univariate and probabilistic sensitivity analyses determined the influence of input variation on the cost-effectiveness. ICU. Hypothetical cohort of adults admitted to the ICU. Three prevention strategies were evaluated, including universal decolonization, targeted decolonization, and screening and isolation. Because prevention strategies have a screening component, the screening test in the model was varied to reflect commonly used screening test categories, including conventional culture, chromogenic agar, and polymerase chain reaction. Universal and targeted decolonization are less costly and more effective than screening and isolation. This is consistent for all screening tests. When compared with targeted decolonization, universal decolonization is cost-saving to cost-effective, with maximum cost savings occurring when a hospital uses more expensive screening tests like polymerase chain reaction. Results were robust to sensitivity analyses. As compared with screening and isolation, the current standard practice in ICUs, targeted decolonization, and universal decolonization are less costly and more effective. This supports updating the standard practice to a decolonization approach.

  20. 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.

  1. Nasal carriage of methicillin-resistant Staphylococcus pseudintermedius in dogs treated with cephalexin monohydrate.

    PubMed

    Fungwithaya, Punpichaya; Chanchaithong, Pattrarat; Phumthanakorn, Nathita; Prapasarakul, Nuvee

    2017-01-01

    This study aimed to investigate the nasal carriage of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in dogs treated with oral cephalexin monohydrate. Ten dogs with superficial pyoderma were monitored longitudinally for carriage of MRSP for up to 1 year after treatment; the strains were typed and antibiograms were determined. Methicillin-susceptible S. pseudintermedius (MSSP) was recovered prior to treatment in all dogs and could be isolated after 12 months in 1 dog. Methicillin-resistant Staphylococcus pseudintermedius was detected within 1 week of treatment in all dogs, and 3 clones represented by ST45, ST112, and ST181 were consistently present for up to 12 months after treatment. All MRSP isolates were resistant to at least 7 common antimicrobials. Oral cephalexin monohydrate treatment selected for strains of multi-resistant MRSP, which were still present after 1 year.

  2. 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.

  3. 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

  4. 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.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26273270

  6. 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.

  7. 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.

  8. 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.

  9. Methicillin-Resistant Staphylococcus aureus Vertebral Osteomyelitis Following Epidural Catheterization: A Case Report and Literature Review

    PubMed Central

    Krishnakumar, R.; Renjitkumar, J.

    2012-01-01

    Indwelling epidural catheters are frequently used to manage postoperative pain. This report describes a patient who developed methicillin-resistant Staphylococcus aureus (MRSA) vertebral osteomyelitis of the lumbar spine following epidural catheterization. To the best of our knowledge, this is the first reported case of MRSA vertebral osteomyelitis secondary to epidural catheter use in the English orthopedic literature. The patient and his family consented to publishing the data. PMID:24353973

  10. Ceftaroline Fosamil for Methicillin-Resistant Staphylococcus aureus Pulmonary Exacerbation in a Pediatric Cystic Fibrosis Patient

    PubMed Central

    Snyder, Ashley Hall; Srivastava, Ruma; Rybak, Michael J.; McGrath, Eric

    2014-01-01

    Ceftaroline, an advanced generation cephalosporin with activity against methicillin-resistant Staphylococcus aureus (MRSA), may present a new therapeutic alternative for treating lung infections among patients with cystic fibrosis. We report a case of ceftaroline therapy in a pediatric patient with cystic fibrosis, whose dose was increased from 9.7 mg/kg/dose every 12 hours to 10.8 mg/kg/dose every 8 hours by using pharmacokinetic analyses. PMID:25024675

  11. Are toilet seats a vector for transmission of methicillin-resistant Staphylococcus aureus?

    PubMed

    Giannini, Mary Anne; Nance, Donna; McCullers, Jonathan A

    2009-08-01

    We studied the bacterial burden on toilet seats in a children's cancer hospital to validate a policy requesting that immunocompromised children use alcohol wipes on the seats prior to use of the toilets. Methicillin-resistant Staphylococcus aureus (MRSA) was recovered from 3.3% of hospital toilets when wipes were not in use. Use of wipes resulted in a 50-fold reduction in mean daily bacterial counts and eliminated MRSA.

  12. Methicillin-Resistant Staphylococcus aureus Harboring mecC in Livestock in Spain

    PubMed Central

    Ariza-Miguel, Jaime; Fernández-Natal, Isabel

    2014-01-01

    We report for the first time mecC-positive methicillin-resistant Staphylococcus aureus (mecC-MRSA) in livestock in Spain. One isolate (sequence type 130) was found in milk samples among 601 S. aureus isolates obtained from 229 dairy sheep farms. This finding highlights the potential for zoonotic transmission of mecC-positive MRSA and the need for surveillance programs to monitor its presence and clonal evolution. PMID:25187631

  13. Methicillin-resistant Staphylococcus aureus infections: role of daptomycin/β-lactams combination.

    PubMed

    Leone, Sebastiano; Noviello, Silvana; Boccia, Giovanni; De Caro, Francesco; Esposito, Silvano

    2015-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) associated infection has become a worrisome issue worldwide. Glycopeptides are the backbone antibiotics for the treatment of MRSA infections. However, several reports have highlighted the limitations of vancomycin. Daptomycin is successfully used for the treatment of serious MRSA infections, however selection of resistant strains has been reported during daptomycin-monotherapy. This review will briefly discuss the available data on daptomycin/beta-lactam combination therapies for the treatment of MRSA infections.

  14. Community-acquired methicillin resistant Staphylococcus aureus: a new aetiological agent of prostatic abscess

    PubMed Central

    Abreu, Diego; Arroyo, Carlos; Suarez, Ruben; Campolo, Horacio; Izaguirre, Juan; Decía, Ricardo; Machado, Miguel; Carvalhal, Gustavo Franco; Clavijo, Jorge

    2011-01-01

    Prostatic abscess is rare. Its potentially serious course requires a high level of clinical suspicion and prompt and effective treatment. The causative germs are usually either enterobacteria or Enterococcus. The authors highlight the importance of considering epidemiological and clinical aspects in the early diagnosis and treatment. Prostatic abscess due to community-acquired methicillin resistant Staphylococcus has three typical characteristics: skin entry point, periprostatic compromise, and anaemia and low prothrombin. PMID:22696740

  15. Novel inhibitors of the methicillin-resistant Staphylococcus aureus (MRSA)-pyruvate kinase.

    PubMed

    El-Sayed, Mardia Telep; Zoraghi, Roya; Reiner, Neil; Suzen, Sibel; Ohlsen, Knut; Lalk, Michael; Altanlar, Nurten; Hilgeroth, Andreas

    2016-12-01

    Novel bisindolyl-cycloalkane indoles resulted from the reaction of aliphatic dialdehydes and indole. As bisindolyl-natural alkaloid compounds have recently been reported as inhibitors of the methicillin-resistant Staphylococcus aureus (MRSA)-pyruvate kinase (PK), we tested our novel compounds as MRSA PK inhibitors and now report first inhibiting activities. We discuss structure-activity relationships of structurally varied compounds. Activity influencing substituents have been characterized and relations to antibacterial activities of the most active compounds have been proved.

  16. Tea tree oil as an alternative topical decolonization agent for methicillin-resistant Staphylococcus aureus.

    PubMed

    Caelli, M; Porteous, J; Carson, C F; Heller, R; Riley, T V

    2000-11-01

    The combination of a 4% tea tree oil nasal ointment and 5% tea tree oil body wash was compared with a standard 2% mupirocin nasal ointment and triclosan body wash for the eradication of methicillin-resistant Staphylococcus aureus carriage. The tea tree oil combination appeared to perform better than the standard combination, although the difference was not statistically significant due to the small number of patients.

  17. The relationship of immunity and nutrition to the acquisition of methicillin-resistant Staphylococcus aureus.

    PubMed Central

    Jayne, M. B.; Bellknap, D. C.; Flournoy, D. J.

    1991-01-01

    Selected nutritional and immunological indices of 118 patients with methicillin-resistant Staphylococcus aureus (MRSA) were reviewed retrospectively. Those patients with nosocomial infections had significantly (P less than .05) lower levels of serum albumin, total protein, absolute lymphocyte, and percentage of lymphocytes (on differential) than all others (ie, community-acquired infections and colonizations and nosocomial colonizations). Therefore, these parameters might be important indicators of subsequent MRSA infestation in certain patient populations. PMID:1920516

  18. Chlorhexidine whole-body washing of patients reduces methicillin-resistant Staphylococcus aureus and has a direct effect on the distribution of the ST5-MRSA-II (New York/Japan) clone.

    PubMed

    Velázquez-Meza, Maria Elena; Mendoza-Olazarán, Soraya; Echániz-Aviles, Gabriela; Camacho-Ortiz, Adrián; Martínez-Reséndez, Michel Fernando; Valero-Moreno, Vanessa; Garza-González, Elvira

    2017-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) colonizes the skin of hospitalized patients and is associated with high morbidity and mortality. To prevent colonization and infection by S. aureus, better disinfection practices are required. Therefore, we evaluated the effect of chlorhexidine whole-body washing on hospital-acquired S. aureus infections among intensive care unit (ICU) patients in a tertiary hospital in Mexico. The study was conducted over 18 months to evaluate the effect of 2 % chlorhexidine gluconate (CXG) whole-body washing of ICU adult patients on chlorhexidine and antibiotic resistance, biofilm production and clonal distribution of S. aureus in a tertiary care hospital. Minimum inhibitory concentrations for CXG, antibiotic susceptibility and biofilm production by S. aureus isolates were determined. Pulsed-field gel electrophoresis, multilocus sequence typing (MLST) and PCR for Panton-Valentine leucocidin (PVL) were used for molecular typing of MRSA isolates.Results/Key findings. We included 158 isolates. A reduction in antibiotic resistance in the study period was observed for clindamycin, levofloxacin, norfloxacin, oxacillin and trimethoprim/sulfamethoxazole. None of the isolates showed reduced susceptibility to CXG. Most of the isolates were non-biofilm producers (147/158). The most commonly identified clone was a descendant of the ST5-MRSA-II (New York/Japan) clone. This clone decreased during the intervention period and reappeared markedly in the post-intervention period. During the post-intervention period, two isolates were related with the clone ST8-MRSA-IV (also known as USA300). Our findings suggest that the CXG bathing favored the reduction of healthcare-associated MRSA isolates and a temporary reduction of the predominant ST5-MRSA-II (New York/Japan) clone.

  19. Cell Wall Composition and Associated Properties of Methicillin-Resistant Staphylococcus aureus Strains

    PubMed Central

    Wilkinson, Brian J.; Dorian, Kenneth J.; Sabath, L. D.

    1978-01-01

    Methicillin-resistant (MR) Staphylococcus aureus strains have previously been reported to be deficient in surface negative charge; this has been correlated with methicillin resistance and ascribed to a deficiency of teichoic acid at the cell surface (A. W. Hill and A. M. James, Microbios 6:157-167, 1972). Teichoic acid was present in walls of MR organisms as revealed by appreciable phosphate levels and detection of ribitol residues. Phosphate levels in walls from five MR strains (0.54 to 0.77 μmol/mg of wall) were lower than in three unrelated methicillin-sensitive (MS) strains (0.86 to 1.0 μmol/mg of wall). However, two MS strains derived from two of the MR strains had wall phosphate levels very similar to those of the MR strains. No evidence for unusual wall polymers was found. Simple deficiency of wall teichoic acid does not result in methicillin resistance since an independently isolated teichoic acid-deficient strain (0.1 μmol of phosphate per mg of wall) was not methicillin resistant. In studies of biological properties possibly related to wall teichoic acid, it was discovered that walls isolated from MR organisms grown in the presence of methicillin autolyzed more rapidly than those isolated from organisms grown in the absence of the drug. Since methicillin resistance is enhanced by NaCl and suppressed by ethylenediaminetetraacetate, the effects of these compounds on autolysis of isolated walls were studied. NaCl (1.0 M) and ethylenediaminetetraacetate (1.0 mM) inhibited the autolysis of walls isolated from MR and MS strains. An MR strain bound phage 47, 52A, and 3A only slightly less well than their respective propagating strains. PMID:152758

  20. Methicillin-resistant Staphylococcus aureus: Prevalence, incidence, risk factors, and effects on survival of patients in a specialist palliative care unit: A prospective observational study.

    PubMed

    Gleeson, Aoife; Larkin, Philip; Walsh, Cathal; O'Sullivan, Niamh

    2016-04-01

    Little is known about the impact of methicillin-resistant Staphylococcus aureus in palliative care settings. To date, the clinical impact of methicillin-resistant Staphylococcus aureus in palliative care is unknown. To determine prevalence and incidence of methicillin-resistant Staphylococcus aureus colonisation in a specialist palliative care setting, to identify risk factors for methicillin-resistant Staphylococcus aureus colonisation, to determine the eradication success rate and to determine the impact of methicillin-resistant Staphylococcus aureus on survival. Prospective cohort study. Data were collected for consecutive admissions to an inpatient palliative care service. Patients were screened for methicillin-resistant Staphylococcus aureus colonisation on admission and 1 week post admission. Methicillin-resistant Staphylococcus aureus eradication was attempted in methicillin-resistant Staphylococcus aureus positive patients. Data were collected from 609 admissions for 466 individual patients. Admission screening data were available in 95.5%. Prevalence of methicillin-resistant Staphylococcus aureus colonisation was 11.59% (54 patients). One week incidence of methicillin-resistant Staphylococcus aureus colonisation was 1.2%. Risk factors for methicillin-resistant Staphylococcus aureus colonisation were determined using Chi-Squared test and included high Waterlow score (p < 0.01), high palliative performance scale score (p < 0.01), methicillin-resistant Staphylococcus aureus status prior to admission (p < 0.01), admission from hospital (p < 0.05), presence of urinary catheter or percutaneous endoscopic gastrostomy tube (p < 0.05) and poor dietary intake (p < 0.05). Regression analysis did not identify independent risk factors. Methicillin-resistant Staphylococcus aureus was eradicated in 8.1% of admissions, while 46 patients commenced on the protocol (62.2%) died before completing it. Methicillin-resistant Staphylococcus aureus did

  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.

  2. Tolerability of a probiotic in subjects with a history of methicillin-resistant Staphylococcus aureus colonisation.

    PubMed

    Warrack, S; Panjikar, P; Duster, M; Safdar, N

    2014-06-02

    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.

  3. Laboratory evaluation of phenotypic detection methods of methicillin-resistant Staphylococcus aureus.

    PubMed

    Kali, Arunava; Stephen, Selvaraj; Umadevi, Sivaraman

    2014-01-01

    Although conventional antibiotic susceptibility tests are most commonly performed for methicillin-resistant Staphylococcus aureus (MRSA), the results of these phenotypic tests are dependent on the standardization of the culture conditions. The aim of the study was to evaluate the conventional phenotypic screening tests in comparison to the mecA gene polymerase chain reaction (PCR). One hundred and two clinical isolates of MRSA identified by the oxacillin disk diffusion were subjected to PCR for the mecA gene and by the cefoxitin disk diffusion test and culture on oxacillin screen agar, mannitol salt agar, and methicillin-resistant Staphylococcus aureus Agar (MeReSA) selective medium, for MRSA. Although all 102 isolates were resistant in oxacillin and cefoxitin disk diffusion, 92 (90.1%) isolates were positive for the mecA gene. The sensitivities of the mannitol salt agar, MeReSA agar, and oxacillin screen agar were 89.13, 97.82, and 98.91%, respectively. The oxacillin screen agar may be recommended for confirming methicillin resistance in the disk diffusion test in resource-poor settings, where molecular methods are not available.

  4. Absence of Circular Plasmid Deoxyribonucleic Acid Attributable to a Genetic Determinant for Methicillin Resistance in Staphylococcus aureus

    PubMed Central

    Stiffler, Paul W.; Sweeney, H. M.; Cohen, Sidney

    1973-01-01

    Plasmid deoxyribonucleic acid was not detected by centrifugal analysis of lysates of penicillinase-negative strains of Staphylococcus aureus harboring a determinant of methicillin resistance derived from strain Villaluz. When these strains contained a penicillinase plasmid, the plasmid deoxyribonucleic acid of methicillin-resistant and methicillin-susceptible strains was indistinguishable by the methods employed. The results indicate that the genetic determinant for methicillin resistance in the strains examined was not associated with a circular plasmid comparable to those that have been shown to determine resistance to benzylpenicillin, tetracycline, and chloramphenicol in S. aureus. PMID:4490525

  5. Methicillin-resistant Staphylococcus aureus infections in U.S. service members deployed to Iraq.

    PubMed

    Roberts, Stephen S; Kazragis, Robert J

    2009-04-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has become the most common cause of skin and soft-tissue infections in the United States. However, no studies have yet examined its importance in the deployed environment. We retrospectively reviewed culture results obtained at a level II military treatment facility in Iraq over a 5-month period to determine the incidence of CA-MRSA in this population. Eighty-five percent of the cultures obtained from skin abscesses were positive for S. aureus, and 70% were methicillin-resistant S. aureus. All of the isolates recovered were sensitive to trimethoprim/sulfamethoxazole. CA-MRSA is a significant problem in deployed service members and civilians and empiric antibiotics for skin and soft-tissue infections need to provide coverage for this important pathogen.

  6. 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

  7. 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.

  8. 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.

  9. Crohn's disease complicated by intestinal infection with methicillin-resistant Staphylococcus aureus.

    PubMed

    Bettenworth, Dominik; Nowacki, Tobias M; Friedrich, Alexander; Becker, Karsten; Wessling, Johannes; Heidemann, Jan

    2013-07-21

    We report on a 24-year-old male patient with history of bloody diarrhea, abdominal pain and vomiting. Endoscopy revealed massive ulcerative discontinuous proctosigmoiditis with deep, sharply demarcated epithelial denudations and enterotoxigenic methicillin-resistant Staphylococcus aureus (MRSA) was detected in mucosal biopsies. After treatment with linezolide and steroids, a significant amelioration of colitis was detected and testing for MRSA became negative. In face of the case presented here, we suggest that in patients with refractory inflammatory bowel disease (IBD), microbiological assessment should be performed to detect a possible Staphylococcus aureus infection in order to initiate an antimicrobial treatment in addition to IBD-specific treatment.

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

    PubMed

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

    2009-12-01

    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. 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. 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). 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.

  11. Presence of the optrA Gene in Methicillin-Resistant Staphylococcus sciuri of Porcine Origin.

    PubMed

    Fan, Run; Li, Dexi; Wang, Yang; He, Tao; Feßler, Andrea T; Schwarz, Stefan; Wu, Congming

    2016-12-01

    A total of 57 methicillin-resistant Staphylococcus aureus (MRSA) isolates and 475 methicillin-resistant coagulase-negative staphylococci (MRCoNS) collected from pigs in the Guangdong province of China in 2014 were investigated for the presence of the novel oxazolidinone-phenicol resistance gene optrA The optrA gene was detected in 6.9% (n = 33) of the MRCoNS, all of which were Staphylococcus sciuri isolates, but in none of the MRSA isolates. Five optrA-carrying methicillin-resistant (MR) S. sciuri isolates also harbored the multiresistance gene cfr Pulsed-field gel electrophoresis (PFGE) and dru typing of the 33 optrA-carrying MR S. sciuri isolates revealed 25 patterns and 5 sequence types, respectively. S1 nuclease PFGE and Southern blotting confirmed that optrA was located in the chromosomal DNAs of 29 isolates, including 1 cfr-positive isolate. The remaining four isolates harbored a ∼35-kb pWo28-3-like plasmid on which optrA and cfr were located together with other resistance genes, as confirmed by sequence analysis. Six different types of genetic environments (types I to VI) of the chromosome-borne optrA genes were identified; these types had the optrA gene and its transcriptional regulator araC in common. Tn558 was found to be associated with araC-optrA in types II to VI. The optrA gene in types II and III was found in close proximity to the ccr gene complex of the respective staphylococcal cassette chromosome mec element (SCCmec). Since oxazolidinones are last-resort antimicrobial agents for the control of serious infections caused by methicillin-resistant staphylococci in humans, the location of the optrA gene close to the ccr complex is an alarming observation. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  12. Antibacterial properties of cetyltrimethylammonium bromide-stabilized green silver nanoparticles against methicillin-resistant Staphylococcus aureus.

    PubMed

    Jang, Hyoyeong; Lim, Soo Hyeon; Choi, Jae Sue; Park, Youmie

    2015-10-01

    Silver nanoparticles (AgNPs) were synthesized using Artemisia capillaris extracts in the absence and presence of stabilizers, and the antibacterial activities of the AgNPs against methicillin-resistant Staphylococcus aureus (MRSA) were determined by a minimum inhibitory concentration (MIC) assay. Two stabilizers, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), were utilized during the one-step synthesis to increase the colloidal stability of the AgNPs. The extract of A. capillaris was used as a reducing agent to convert silver ions into AgNPs. Sharp surface plasmon resonance bands in the range of 423-426 nm were observed in the UV-Visible spectra of the AgNPs, which indicated that the AgNPs were predominantly spherical shaped. Their average diameter, which ranged from 15.11 to 16.54 nm, was measured from high-resolution transmission electron microscopy images. Remarkably, the CTAB-stabilized AgNPs exhibited greater antibacterial activity (2- to 8-fold increase, MIC 15.6-62.5 μg/mL) against MRSA compared with the extract, AgNPs prepared in the absence of stabilizers, and SDS-stabilized AgNPs. The results indicate that CTAB-stabilized AgNPs prepared using plant extracts as reducing agents are very promising for the development of novel antibacterial agents.

  13. Prevalence of Staphylococcus aureus and methicillin resistant Staphylococcus aureus (MRSA) in the oral cavity.

    PubMed

    Koukos, Georgios; Sakellari, Dimitra; Arsenakis, Minas; Tsalikis, Lazaros; Slini, Theodora; Konstantinidis, Antonios

    2015-09-01

    To assess the prevalence of Staphylococcus aureus and methicillin resistant Staphylococcus aureus (MRSA) in plaque and tongue samples from systemically healthy subjects with periodontal health, gingivitis or chronic periodontitis. After screening 720 potentially eligible subjects, 154 systemically healthy participants were ultimately enrolled in the current study. Subgingival samples were taken from the first molars and the tongue and analyzed for the presence of S. aureus and MRSA by polymerase chain reaction (PCR), using primers and conditions previously described in the literature. In addition, samples were taken from deep periodontal pockets of chronic periodontitis patients. Statistical analysis was performed by applying non-parametric tests (Kruskal-Wallis for clinical parameters, and z-test with Bonferroni corrections for distributions of assessed parameters). All comparisons were set at the 0.05 significance level. S. aureus was detected in 18% of all participants and in 10% of the samples tested. No significant differences were found in its distribution among the three investigated groups (z-test for proportions with Bonferroni corrections, p>0.05). The mecA gene was not present in any of the S. aureus found. S. aureus can be found in the oral environment regardless of the periodontal conditions and therefore should be considered as a member of the transient flora not participating in periodontal pathology. Subgingival sites and tongue surfaces seem to be an unusual habitat of MRSA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. 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

  15. [Comparison of three selective chromogenic media for Methicillin-Resistant Staphylococcus aureus detection].

    PubMed

    Athanasopoulos, A; Devogel, P; Beken, C; Pille, C; Bernier, I; Gavage, P

    2007-11-01

    Rapid detection of Methicillin-Resistant Staphylococcus aureus (MRSA) is of major importance in hospital hygiene. In order to reduce the response time from screening laboratories, new selective chromogenic media have been developed and marketed by major microbiology companies. In this context, an evaluation of their performances was needed. Media produced by Bio-Rad Laboratories (MRSASelect), Becton Dickinson (CHROMagar MRSA) and bioMérieux (chromID MRSA) were studied by 203screening samples, 110 of which were MRSA positive. Each Stahylococcus aureus was identified by catalase detection, Staphytect Plus Dryspot latex agglutination test and free coagulase detection, in addition to mannitol fermentation and Voges-Proskauer tests in the case of doubtful identification. Resistance was verified by checking the inhibition zone diameter of under 20 mm on 30 microg cefoxitin disks. Bio-Rad Laboratories, Becton Dickinson and bioMérieux media read at 24 or 24/48 hours have a respective sensitivity of 91, 71 and 85/92%. The specificity of these media is 99, 100 and 99/93%. These media proved to be new powerful and rapid tools used in screening for MRSA detection. MRSASelect is one of the most effective media showing high sensitivity and specificity and the easiest interpretation. chromID MRSA exhibits similar performance but needs more time to be as effective as Bio-Rad media while CHROMagar MRSA isn't enough efficient with its slightly lack of sensitivity to perform a reliable screening.

  16. The Mechanism Underlying the Antibacterial Activity of Shikonin against Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Lee, Young-Seob; Lee, Dae-Young; Kim, Yeon Bok; Lee, Sang-Won; Cha, Seon-Woo; Park, Hong-Woo; Kim, Geum-Soog; Kwon, Dong-Yeul; Lee, Min-Ho; Han, Sin-Hee

    2015-01-01

    Shikonin (SKN), a highly liposoluble naphthoquinone pigment isolated from the roots of Lithospermum erythrorhizon, is known to exert antibacterial, wound-healing, anti-inflammatory, antithrombotic, and antitumor effects. The aim of this study was to examine SKN antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). The SKN was analyzed in combination with membrane-permeabilizing agents Tris and Triton X-100, ATPase inhibitors sodium azide and N,N′-dicyclohexylcarbodiimide, and S. aureus-derived peptidoglycan; the effects on MRSA viability were evaluated by the broth microdilution method, time-kill test, and transmission electron microscopy. Addition of membrane-permeabilizing agents or ATPase inhibitors together with a low dose of SKN potentiated SKN anti-MRSA activity, as evidenced by the reduction of MRSA cell density by 75% compared to that observed when SKN was used alone; in contrast, addition of peptidoglycan blocked the antibacterial activity of SKN. The results indicate that the anti-MRSA effect of SKN is associated with its affinity to peptidoglycan, the permeability of the cytoplasmic membrane, and the activity of ATP-binding cassette (ABC) transporters. This study revealed the potential of SKN as an effective natural antibiotic and of its possible use to substantially reduce the use of existing antibiotic may also be important for understanding the mechanism underlying the antibacterial activity of natural compounds. PMID:26265924

  17. Nafcillin Enhances Innate Immune-Mediated Killing of Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Sakoulas, George; Okumura, Cheryl Y.; Thienphrapa, Wdee; Olson, Joshua; Nonejuie, Poochit; Dam, Quang; Dhand, Abhay; Pogliano, Joseph; Yeaman, Michael R.; Hensler, Mary E.; Bayer, Arnold S.; Nizet, Victor

    2014-01-01

    Based on in vitro synergy studies, the addition of nafcillin to daptomycin was used to treat refractory methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. Daptomycin is a de facto cationic antimicrobial peptide in vivo, with antistaphylococcal mechanisms reminiscent of innate host defense peptides (HDPs). In this study, the effects of nafcillin on HDP activity against MRSA were examined in vitro and in vivo. Exposures to β-lactam antimicrobials in general, and nafcillin in particular, significantly increased killing of S. aureus by selected HDPs from, keratinocytes, neutrophils and platelets. This finding correlated with enhanced killing of MRSA by whole blood, neutrophils and keratinocytes after growth in nafcillin. Finally, nafcillin pretreatment ex vivo reduced MRSA virulence in a murine subcutaneous infection model. Despite the lack of direct activity against MRSA, these studies show potent, consistent, and generalized nafcillin-mediated ‘sensitization’ to increased killing of MRSA by various components of the innate host response. The use of nafcillin as adjunctive therapy in MRSA bacteremia merits further study and should be considered in cases refractory to standard therapy. PMID:24297496

  18. High-throughput screening of colonization samples for methicillin-resistant Staphylococcus aureus.

    PubMed

    Stenholm, Teppo; Hakanen, Antti J; Hakanen, Emmi; Härmä, Harri; Österblad, Monica; Vuopio, Jaana; Hänninen, Pekka E; Huovinen, Pentti; Rankakokko-Jalava, Kaisu; Kotilainen, Pirkko

    2013-12-01

    We present here the first application of 2-photon excited fluorescence detection (TPX) technology for the direct screening of clinical colonization samples for methicillin-resistant Staphylococcus aureus (MRSA). A total of 125 samples from 14 patients with previously identified MRSA carriage and 16 controls from low-prevalence settings were examined. The results were compared to those obtained by both standard phenotypic and molecular methods. In identifying MRSA carriers, i.e. persons with at least 1 MRSA positive colonization sample by standard methods, the sensitivity of the TPX technique was 100%, the specificity 78%, the positive predictive value 75%, and the negative predictive value 100%. The TPX assay sensitivity per colonization sample was 89%, the specificity 93%, the positive predictive value 84%, and the negative predictive value 95%. The median time for a true-positive test result was 3 h and 26 min; negative test results are available after 13 h. The assay capacity was 48 samples per test run. The TPX MRSA technique could provide early preliminary results for clinicians, while simultaneously functioning as a selective enrichment step for further conventional testing. Costs and workload associated with hospital infection control can be reduced using this high-throughput, point-of-care compatible methodology.

  19. Occurrence and molecular characteristics of methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus pseudintermedius in an academic veterinary hospital.

    PubMed

    Ishihara, Kanako; Shimokubo, Natsumi; Sakagami, Akie; Ueno, Hiroshi; Muramatsu, Yasukazu; Kadosawa, Tsuyoshi; Yanagisawa, Chie; Hanaki, Hideaki; Nakajima, Chie; Suzuki, Yasuhiko; Tamura, Yutaka

    2010-08-01

    Recently, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) have been increasingly isolated from veterinarians and companion animals. With a view to preventing the spread of MRSA and MRSP, we evaluated the occurrence and molecular characteristics of each in a veterinary college. MRSA and MRSP were isolated from nasal samples from veterinarians, staff members, and veterinary students affiliated with a veterinary hospital. Using stepwise logistic regression, we identified two factors associated with MRSA carriage: (i) contact with an identified animal MRSA case (odds ratio [OR], 6.9; 95% confidence interval [95% CI], 2.2 to 21.6) and (ii) being an employee (OR, 6.2; 95% CI, 2.0 to 19.4). The majority of MRSA isolates obtained from individuals affiliated with the veterinary hospital and dog patients harbored spa type t002 and a type II staphylococcal cassette chromosome mec (SCCmec), similar to the hospital-acquired MRSA isolates in Japan. MRSA isolates harboring spa type t008 and a type IV SCCmec were obtained from one veterinarian on three different sampling occasions and also from dog patients. MRSA carriers can also be a source of MRSA infection in animals. The majority of MRSP isolates (85.2%) carried hybrid SCCmec type II-III, and almost all the remaining MRSP isolates (11.1%) carried SCCmec type V. MRSA and MRSP were also isolated from environmental samples collected from the veterinary hospital (5.1% and 6.4%, respectively). The application of certain disinfection procedures is important for the prevention of nosocomial infection, and MRSA and MRSP infection control strategies should be adopted in veterinary medical practice.

  20. Occurrence and Molecular Characteristics of Methicillin-Resistant Staphylococcus aureus and Methicillin-Resistant Staphylococcus pseudintermedius in an Academic Veterinary Hospital▿

    PubMed Central

    Ishihara, Kanako; Shimokubo, Natsumi; Sakagami, Akie; Ueno, Hiroshi; Muramatsu, Yasukazu; Kadosawa, Tsuyoshi; Yanagisawa, Chie; Hanaki, Hideaki; Nakajima, Chie; Suzuki, Yasuhiko; Tamura, Yutaka

    2010-01-01

    Recently, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) have been increasingly isolated from veterinarians and companion animals. With a view to preventing the spread of MRSA and MRSP, we evaluated the occurrence and molecular characteristics of each in a veterinary college. MRSA and MRSP were isolated from nasal samples from veterinarians, staff members, and veterinary students affiliated with a veterinary hospital. Using stepwise logistic regression, we identified two factors associated with MRSA carriage: (i) contact with an identified animal MRSA case (odds ratio [OR], 6.9; 95% confidence interval [95% CI], 2.2 to 21.6) and (ii) being an employee (OR, 6.2; 95% CI, 2.0 to 19.4). The majority of MRSA isolates obtained from individuals affiliated with the veterinary hospital and dog patients harbored spa type t002 and a type II staphylococcal cassette chromosome mec (SCCmec), similar to the hospital-acquired MRSA isolates in Japan. MRSA isolates harboring spa type t008 and a type IV SCCmec were obtained from one veterinarian on three different sampling occasions and also from dog patients. MRSA carriers can also be a source of MRSA infection in animals. The majority of MRSP isolates (85.2%) carried hybrid SCCmec type II-III, and almost all the remaining MRSP isolates (11.1%) carried SCCmec type V. MRSA and MRSP were also isolated from environmental samples collected from the veterinary hospital (5.1% and 6.4%, respectively). The application of certain disinfection procedures is important for the prevention of nosocomial infection, and MRSA and MRSP infection control strategies should be adopted in veterinary medical practice. PMID:20543040

  1. 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.

  2. PCR-based identification of methicillin-resistant Staphylococcus aureus strains and their antibiotic resistance profiles

    PubMed Central

    Pournajaf, Abazar; Ardebili, Abdollah; Goudarzi, Leyla; Khodabandeh, Mahmoud; Narimani, Tahmineh; Abbaszadeh, Hassan

    2014-01-01

    Objective To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification. Methods A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates. Results Among antibiotics used in our study, penicillin showed the least anti-staphylococcal activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA- positive in the PCR assay. Conclusions This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic. PMID:25183100

  3. 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

  4. 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.

  5. [Risk factors for methicillin-resistant Staphylococcus aureus bacteremia: A multicenter matched case-control study].

    PubMed

    Arias-Ortiz, Paola Mariana; Calderón, Libia Del Pilar; Castillo, Juan Sebastián; Moreno, José; Leal, Aura Lucía; Cortés, Jorge Alberto; Álvarez, Carlos Arturo; Grebo, Grupo

    2016-12-01

    Methicillin-resistant Staphylococcus aureus is a frequent pathogen at critical care services. Its presence leads to increased hospital stays and mortality risk in patients with bacteremia. However, the etiology of this resistance marker has not been fully studied. To identify risk factors associated with the emergence of methicillin-resistant S. aureus bacteremia in critically ill patients treated at intensive care units in Bogotá, Colombia. We conducted a retrospective paired case-control study, nested in a cohort of patients diagnosed with S. aureus bacteremia and treated at intensive care units between 2006 and 2008 in Bogotá. Cases were patients with positive blood culture to methicillin resistance, matched in a 1:1 ratio with methicillin-sensitive controls isolated from the same institution and hospitalization year. We used conditional logistic regression to analyze the risk factors associated with the presence of resistance, with emphasis on prior antibiotic therapy. We included 372 patients with S. aureus bacteremia. Factors such as the use of pre-hospital devices: vascular (OR=1.986, 95% CI 1.038 to 3.801) and urinary (OR=2.559, 95% CI: 1.170 to 5.596), along with the number of previously used antibiotics, were associated with the emergence of resistance. The number of antibiotics used previously was determined to have a gradient effect, particularly carbapenems. The rational use of antibiotics and surveillance of exposure to surgical procedures or use of invasive devices are interventions that could diminish the emergence of methicillin-resistant S. aureus bacteremia causes.

  6. [Methicillin resistant Staphylococcus aureus community acquired meningitis: a case report].

    PubMed

    Spini, Roxana Gabriela; Ferraris, Verónica; Glasman, María Patricia; Orofino, Guillermina; Casanovas, Alejandra; Debaisi, Gustavo

    2014-12-01

    Community-acquired Staphylococcus aureus (CA-SA) infections are becoming more frequent. Most cases present an infection of skin and soft tissue, and the most invasive forms observed are osteoarticular and pleuropulmonary infections. Meningitis is a rare manifestation of Staphylococcus aureus infections. We describe an unusual case of CA-MRSA infection. An infant of eight months presented with signs of irritability and 4 days duration fever, with alternating sensory and abdomen pain. Acute abdomen surgery was discarded and hospitalization was decided with diagnosis of sepsis due to probable enteral focus; antibiotics were indicated. Blood cultures and cerebrospinal fluid culture were positive for MRSA. Sepsis with meningitis by MRSA was diagnosed. On the 7th day of hospitalization the infant presented neurological signs and symptoms. On the resolution computed tomography and the magnetic resonance, images compatible with myelitis were observed. The patient complied with the 21 day endovenous treatment, and showed positive results, being discharged from hospital a month after the appearance of the symptoms.

  7. Evaluation of Ceftaroline Alone and in Combination against Biofilm-Producing Methicillin-Resistant Staphylococcus aureus with Reduced Susceptibility to Daptomycin and Vancomycin in an In Vitro Pharmacokinetic/Pharmacodynamic Model.

    PubMed

    Barber, Katie E; Smith, Jordan R; Ireland, Cortney E; Boles, Blaise R; Rose, Warren E; Rybak, Michael J

    2015-08-01

    Annually, medical device infections are associated with >250,000 catheter-associated bloodstream infections (CLABSI), with up to 25% mortality. Staphylococcus aureus, a primary pathogen in these infections, is capable of biofilm production, allowing organism persistence in harsh environments, offering antimicrobial protection. With increases in S. aureus isolates with reduced susceptibility to current agents, ceftaroline (CPT) offers a therapeutic alternative. Therefore, we evaluated whether CPT would have a role against biofilm-producing methicillin-resistant S. aureus (MRSA), including those with decreased susceptibilities to alternative agents. In this study, we investigated CPT activity alone or combined with daptomycin (DAP) or rifampin (RIF) against 3 clinical biofilm-producing MRSA strains in an in vitro biofilm pharmacokinetic/pharmacodynamic (PK/PD) model. Simulated antimicrobial regimens were as follows: 600 mg of CPT every 8 h (q8h) (free maximum concentration of drug [fCmax], 17.04 mg/liter; elimination half-life [t1/2], 2.66 h), 12 mg/kg of body weight/day of DAP (fCmax, 14.7 mg/liter; t1/2, 8 h), and 450 mg of RIF q12h (fCmax, 3.5 mg/liter; t1/2, 3.4 h), CPT plus DAP, and CPT plus RIF. Samples were obtained and plated to determine colony counts. Differences in log10 CFU/cm(2) were evaluated by analysis of variance with Tukey's post hoc test. The strains were CPT and vancomycin susceptible and DAP nonsusceptible (DNS). CPT displayed activity throughout the experiment. DAP demonstrated initial activity with regrowth at 24 h in all strains. RIF was comparable to the drug-free control, and little benefit was observed when combined with CPT. CPT plus DAP displayed potent activity, with an average log10 CFU/cm(2) reduction of 3.33 ± 1.01 from baseline. CPT demonstrated activity against biofilm-producing DNS MRSA. CPT plus DAP displayed therapeutic enhancement over monotherapy, providing a potential option for difficult-to-treat medical device infections

  8. Telavancin Demonstrates Activity against Methicillin-Resistant Staphylococcus aureus Isolates with Reduced Susceptibility to Vancomycin, Daptomycin, and Linezolid in Broth Microdilution MIC and One-Compartment Pharmacokinetic/Pharmacodynamic Models

    PubMed Central

    Smith, Jordan R.; Barber, Katie E.; Hallesy, Jessica; Raut, Animesh

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) isolates have arisen with reduced susceptibility to several anti-MRSA agents. Telavancin (TLV), a novel anti-MRSA agent, retains low MICs against these organisms. Our objective was to determine the MICs for TLV, daptomycin (DAP), vancomycin (VAN), and linezolid (LZD) against daptomycin-nonsusceptible (DNS) S. aureus, vancomycin-intermediate S. aureus (VISA), heteroresistant VISA (hVISA), and linezolid-resistant (LZDr) S. aureus. We also evaluated these agents against each phenotype in pharmacokinetic/pharmacodynamic (PK/PD) models. Seventy DNS, 100 VISA, 180 hVISA, and 25 LZDr MRSA isolates were randomly selected from our library and tested to determine their MICs against TLV, DAP, VAN, and LZD via broth microdilution and a Trek panel. Four isolates were randomly selected for 168-h in vitro models to evaluate treatment with TLV at 10 mg/kg of body weight/day, DAP at 10 mg/kg/day, VAN at 1 g every 12 h (q12h), and LZD at 600 mg q12h. The MIC50/90 for TLV, DAP, VAN, and LZD against 70 DNS S. aureus isolates were 0.06/0.125 μg/ml, 2/4 μg/ml, 1/2 μg/ml, and 2/2 μg/ml, respectively. Against 100 VISA isolates, the MIC50/90 were 0.06/0.125 μg/ml, 1/1 μg/ml, 4/8 μg/ml, and 1/2 μg/ml, respectively. Against 170 hVISA isolates, the MIC50/90 were 0.06/0.125 μg/ml, 0.5/1 μg/ml, 1/2 μg/ml, and 1/2 μg/ml, respectively. Against 25 LZDr isolates, the MIC50/90 were 0.03/0.06 μg/ml, 1/1 μg/ml, 2/2 μg/ml, and 8/8 μg/ml, respectively. The TLV MIC was >0.125 μg/ml for 10/365 (2.7%) isolates. In PK/PD models, TLV was universally bactericidal at 168 h and statistically superior to all antibiotics against DNS S. aureus strain R2334. These data further establish the potency of TLV against resistant MRSA. The model data demonstrate in vitro bactericidal activity of TLV against hVISA, VISA, DNS S. aureus, and LZDr S. aureus strains. Further clinical research is warranted. PMID:26124162

  9. Evaluation of Ceftaroline Alone and in Combination against Biofilm-Producing Methicillin-Resistant Staphylococcus aureus with Reduced Susceptibility to Daptomycin and Vancomycin in an In Vitro Pharmacokinetic/Pharmacodynamic Model

    PubMed Central

    Barber, Katie E.; Smith, Jordan R.; Ireland, Cortney E.; Boles, Blaise R.; Rose, Warren E.

    2015-01-01

    Annually, medical device infections are associated with >250,000 catheter-associated bloodstream infections (CLABSI), with up to 25% mortality. Staphylococcus aureus, a primary pathogen in these infections, is capable of biofilm production, allowing organism persistence in harsh environments, offering antimicrobial protection. With increases in S. aureus isolates with reduced susceptibility to current agents, ceftaroline (CPT) offers a therapeutic alternative. Therefore, we evaluated whether CPT would have a role against biofilm-producing methicillin-resistant S. aureus (MRSA), including those with decreased susceptibilities to alternative agents. In this study, we investigated CPT activity alone or combined with daptomycin (DAP) or rifampin (RIF) against 3 clinical biofilm-producing MRSA strains in an in vitro biofilm pharmacokinetic/pharmacodynamic (PK/PD) model. Simulated antimicrobial regimens were as follows: 600 mg of CPT every 8 h (q8h) (free maximum concentration of drug [fCmax], 17.04 mg/liter; elimination half-life [t1/2], 2.66 h), 12 mg/kg of body weight/day of DAP (fCmax, 14.7 mg/liter; t1/2, 8 h), and 450 mg of RIF q12h (fCmax, 3.5 mg/liter; t1/2, 3.4 h), CPT plus DAP, and CPT plus RIF. Samples were obtained and plated to determine colony counts. Differences in log10 CFU/cm2 were evaluated by analysis of variance with Tukey's post hoc test. The strains were CPT and vancomycin susceptible and DAP nonsusceptible (DNS). CPT displayed activity throughout the experiment. DAP demonstrated initial activity with regrowth at 24 h in all strains. RIF was comparable to the drug-free control, and little benefit was observed when combined with CPT. CPT plus DAP displayed potent activity, with an average log10 CFU/cm2 reduction of 3.33 ± 1.01 from baseline. CPT demonstrated activity against biofilm-producing DNS MRSA. CPT plus DAP displayed therapeutic enhancement over monotherapy, providing a potential option for difficult-to-treat medical device infections. PMID

  10. Methicillin-Resistant Staphylococcus aureus Prostatic Abscess in a Liver Transplant Recipient

    PubMed Central

    Jana, Tanima; Machicado, Jorge D.; Davogustto, Giovanni E.; Pan, Jen-Jung

    2014-01-01

    Prostatic abscesses are usually related to gram-negative bacilli. However, methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a substantial cause of prostatic abscesses in recent years. Herein, we report the case of a 31-year-old man with a history of orthotopic liver transplantation 10 years ago who presented with acute onset dysuria and abdominal pain and was diagnosed with a MRSA prostatic abscess. To our knowledge, this is the first case describing a prostatic abscess in a liver transplant recipient and the first reporting MRSA as the causative organism of a prostatic abscess in a solid organ transplant recipient. PMID:25389507

  11. Whole-Genome Sequence for Methicillin-Resistant Staphylococcus aureus Strain ATCC BAA-1680.

    PubMed

    Daum, Luke T; Bumah, Violet V; Masson-Meyers, Daniela S; Khubbar, Manjeet; Rodriguez, John D; Fischer, Gerald W; Enwemeka, Chukuka S; Gradus, Steve; Bhattacharyya, Sanjib

    2015-03-12

    We report here the whole-genome sequence of the USA300 strain of methicillin-resistant Staphylococcus aureus (MRSA), designated ATCC BAA-1680, and commonly referred to as community-associated MRSA (CA-MRSA). This clinical MRSA isolate is commercially available from the American Type Culture Collection (ATCC) and is widely utilized as a control strain for research applications and clinical diagnosis. The isolate was propagated in ATCC medium 18, tryptic soy agar, and has been utilized as a model S. aureus strain in several studies, including MRSA genetic analysis after irradiation with 470-nm blue light.

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

    PubMed Central

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

    2015-01-01

    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. PMID:25785319

  13. 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.

  14. Implantable cardioverter defibrillator lead-related methicillin resistant Staphylococcus aureus endocarditis: Importance of heightened awareness

    PubMed Central

    Anusionwu, Obiora F; Smith, Cheri; Cheng, Alan

    2012-01-01

    Methicillin resistant Staphylococcus aureus (MRSA) septicemia is associated with high morbidity and mortality especially in patients with immunosuppression, diabetes, renal disease and endocarditis. There has been an increase in implantation of cardiac implantable electronic devices (CIED) with more cases of device-lead associated endocarditis been seen. A high index of suspicion is required to ensure patient outcomes are optimized. The excimer laser has been very efficient in helping to ensure successful lead extractions in patients with CIED infections. We present an unusual case report and literature review of MRSA septicemia from device-lead endocarditis and the importance of early recognition and prompt treatment. PMID:22905295

  15. Methicillin-resistant Staphylococcus aureus infection in the Texas prison system.

    PubMed

    Baillargeon, Jacques; Kelley, Michael F; Leach, Charles T; Baillargeon, Gwen; Pollock, Brad H

    2004-05-01

    Recent reports indicate that correctional facility inmates may be at elevated risk for contracting methicillin-resistant Staphylococcus aureus (MRSA) infection because of overcrowding, poor hygiene, and high rates of diseases causing immunosuppression. The present study of 299,179 Texas inmates who were incarcerated between 1999-2001 indicated an incidence of 12 MRSA infections/1000 person-years. Inmates with circulatory disease, cardiovascular disease, diabetes, end-stage liver disease, end-stage renal disease, human immunodeficiency virus infection or acquired immunodeficiency syndrome, and skin diseases all exhibited elevated rates of MRSA infection.

  16. 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

  17. First report of swine-associated methicillin-resistant Staphylococcus aureus ST398 in Lithuania.

    PubMed

    Ruzauskas, M; Couto, N; Belas, A; Klimiene, I; Siugzdiniene, R; Pomba, C

    2013-01-01

    During 2011, 160 nasal samples were taken from pigs on 8 different farms in Lithuania. Four methicillin-resistant Staphylococcus aureus (MRSA) isolates were obtained. The isolates were ST398, spa type t011 and SCCmec V and none carried the lukF/lukS genes. Strains were resistant to tetracycline, attributed to tetK and tetM genes, and to erythromycin owing to the ermB gene. One MRSA strain was resistant to trimethoprim/sulfamethoxazole and carried the dfrK gene. This is the first report on the presence and characteristics of livestock-associated MRSA isolated from pigs in Lithuania.

  18. 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

  19. Acquired subglottic stenosis caused by methicillin resistant Staphylococcus aureus that produce epidermal cell differentiation inhibitor

    PubMed Central

    Yamada, Y; Sugai, M; Woo, M; Nishida, N; Sugimoto, T

    2001-01-01

    Local infection of the trachea in intubated neonates is one of the main risk factors for development of acquired subglottic stenosis, although its role in the pathogenesis is unclear. Methicillin resistant Staphylococcus aureus (MRSA) is often the cause of critical illness in neonatal patients. Two cases are reported of acquired subglottic stenosis following bacterial infection of the trachea, suggesting an association with the staphylococcal exotoxin, epidermal cell differentiation inhibitor (EDIN). EDIN-producing MRSA were isolated from purulent tracheal secretions from both infants. Acquired subglottic stenosis in both cases was probably caused by delayed wound healing as the result of EDIN inhibition of epithelial cell migration.

 PMID:11124922

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

    PubMed

    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.

  1. Delayed Diagnosis of Tuberculous Spondylitis Masked by Concomitant Methicillin Resistant Staphylococcus Aureus Infection

    PubMed Central

    Kim, Yong Min

    2010-01-01

    We present a case of tuberculous spondylitis in which diagnosis was masked by a concomitant pyogenic infection. The patient had undergone percutaneous needle aspiration of an abscess in the cavity of the psoas muscle. Early results from the culture regimen showed isolation of methicillin-resistant Staphylococcus aureus. After eight weeks, mycobacterium tuberculosis was grown at regimen which was cultured at the same site. Initial isolation of pyogenic bacteria, considered to be highly virulent organisms, led to delayed diagnosis and treatment of the tuberculosis. PMID:20379481

  2. 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.

  3. Empiric antibiotic therapy for acute osteoarticular infections with suspected methicillin-resistant Staphylococcus aureus or Kingella.

    PubMed

    Saphyakhajon, Phisit; Joshi, Avni Y; Huskins, W Charles; Henry, Nancy K; Boyce, Thomas G

    2008-08-01

    The bacterial agents causing bone and joint infections have been changing. Currently, methicillin-resistant Staphylococcus aureus (MRSA) and Kingella kingae are emerging pathogens. For treatment of MRSA infections, clindamycin, vancomycin, and linezolid are commonly prescribed antibiotics. Kingella are sensitive to most penicillins and cephalosporins. Because MRSA osteoarticular infections tend to be severe, longer periods of antibiotic treatment with more frequent monitoring of inflammatory markers are sometimes required to obtain a complete cure with no residual complications. To assist management, we have included a clinical decision tree with antibiotic treatment protocols.

  4. 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

  5. Proposal for common Nordic epidemiological terms and definitions for methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Skov, Robert; Gudlaugsson, Olafur; Hardardottir, Hjordis; Harthug, Stig; Jakobsen, Trond; Kolmos, Hans Jørn; Olsson-Liljequist, Barbro; Peltonen, Reijo; Tveten, Yngvar; Vuopio-Varkila, Jaana; Ahrén, Christina

    2008-01-01

    The recent increase in the incidence of methicillin-resistant Staphylococcus aureus in all the Nordic countries prompted the Scandinavian Society for Antimicrobial Chemotherapy (SSAC) to create the 'SSAC Working Party on MRSA' with the objective to identify methods to keep the invasive MRSA infections in the Nordic countries below 1%. The lack of common definitions was recognized as a major obstacle for a joint Nordic effort to combat MRSA. The aim of this publication is to present proposals for epidemiological definitions of individual cases, for how to report MRSA frequency per country, and for communication of MRSA strain characteristics between the countries.

  6. Synergistic antibacterial effect of curcumin against methicillin-resistant Staphylococcus aureus.

    PubMed

    Mun, Su-Hyun; Joung, Dae-Ki; Kim, Yong-Sik; Kang, Ok-Hwa; Kim, Sung-Bae; Seo, Yun-Soo; Kim, Youn-Chul; Lee, Dong-Sung; Shin, Dong-Won; Kweon, Kee-Tae; Kwon, Dong-Yeul

    2013-06-15

    Methicillin-resistant Staphylococcus aureus (MRSA) are spread among infected patients, with infection rates increasing at an alarming rate. Furthermore, increased resistance to antibiotics has resulted in serious challenges in the treatment of infectious diseases worldwide. Under the selection pressure of exposure to antibiotics, microorganisms evolve to survive against the new conditions imposed by therapy. Therefore, there exists a need to develop alternative natural or combination drug therapies. Curcumin (CCM), a natural polyphenolic flavonoid isolated from the rhizome of a plant, Curcuma longa Linné., has been found to possess many beneficial biological activities. The aim of this study was to investigate the synergistic effect of curcumin and antibiotics as well as to determine the antibacterial activity of CCM against specific MRSA strains. The antibacterial activity of CCM was assessed by the broth microdilution method (by calculating the minimal inhibitory concentration [MIC]), checkerboard dilution test, and time-kill assay. Antimicrobial activity of CCM was observed against all tested strains. The MICs of CCM against 10 strains of S. aureus ranged from 125 to 250 μg/ml. In the checkerboard test, CCM markedly reduced the MICs of the antibiotics oxacillin (OXI), ampicillin (AMP), ciprofloxacin (CIP), and norfloxacin (NOR) used against MRSA. The time-kill curves showed that a combined CCM and OXI treatment reduced the bacterial counts below the lowest detectable limit after 24h. This study suggested that CCM reduced the MICs of several antibiotics tested, notably of OXI, AMP, CIP, and NOR, and that CCM in combination with antibiotics could lead to the development of new combination of antibiotics against MRSA infection. Copyright © 2013. Published by Elsevier GmbH.

  7. Prevalence of methicillin resistant Staphylococcus aureus in pyogenic community and hospital acquired skin and soft tissues infections.

    PubMed

    Ahmad, Muhammad Khurram; Asrar, Asma

    2014-08-01

    To determine the percentage and frequency of Methicillin Resistant Staphylococcus aureus in community and hospital-acquired pyogenic skin and soft tissue infections. The descriptive cross-sectional study was conducted at the Dermatology Department of Combined Military Hospital, Abbottabad, from June 2009 to March 2010, and comprised 144 community-acquired and 54 hospital-acquired skin and soft tissue infections. Pus swabs from the infected lesions one from each individual were sent to laboratory for culture and sensitivity tests. Methicillin resistance was detected by 1 microg oxacillin disk. Organisms were labelled methicillin-resistant once the inhibition zone for oxocillin was less than 10 mm. Data analysis was done by using SPSS 20. Of the 198 patients in the study, 98 (49.5%) were males and 100 (50.5%) were females, with an overall mean age of 33.7 +/- 14.81 44 years. There were 144 (72.72%) community-acquired infections and 54 (27.27%) had hospital-acquired infections. Community-acquired Methicillin Resistant Staphylococcus aureus numbered 40 (27.8%) and hospital-acquired ones numbered 26 (48.1%). Prevalence of Methicillin Resistant Staphylococcus aureus in community and hospital-acquired pyogenic skin and soft tissue infections was high.

  8. Methicillin-resistant Staphylococcus aureus. A continuing infection control challenge.

    PubMed

    Molinari, John A

    2012-04-01

    The ability of MRSA and other staphylococci to colonize, persist, and adapt to multiple environmental and tissue conditions has allowed for these bacteria to be virtually ubiquitous in their distribution. The effectiveness of commonly used antibiotics, such as penicillin, has continued to decline against infections caused by MRSA and increasingly resistant strains. The challenge for both dental and medical health professionals is to routinely apply proven, evidence-based infection control precautions. As mentioned earlier in this discussion, when compliance with effective aseptic technique practices improves, the patients and environments. Ensure that reusable equipment is not used for the care of another patient until it has been appropriately cleaned and reprocessed and that single-use items are properly discarded. Clean and disinfect clinical contact surfaces that are not barrier-protected by using an environmental protection agency-registered hospital disinfectant with a low- (ie, HIV and HBV label claims) to intermediate-level (ie, tuberculocidal claim) activity after each patient. When the surface is visibly contaminated with blood, an intermediate-incidence of detectable infections can be reduced. Microorganisms will continue to evolve and adapt in order to survive and thrive, sometimes at the expense of susceptible human hosts. The struggle is to constantly remain aware of impending infectious threats which may challenge current precautions, and maintain and improve the quality of infection control to minimize the potential for disease.

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

    PubMed

    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.

  10. Methicillin-resistant Staphylococcus aureus colonization in a pediatric intensive care unit: risk factors.

    PubMed

    Horowitz, Ira N; Baorto, Elizabeth; Cirillo, Tuesday; Davis, Jennifer

    2012-03-01

    Both methicillin-resistant Staphylococcus aureus (MRSA) and penicillin-resistant Streptococcus pneumoniae have become significant causes of disease, both in health care and community settings. All patients admitted to our pediatric intensive care unit (PICU) currently had a rapid test for methicillin-resistant Staphylococcus aureus (MRSA) performed as per hospital guidelines. This study looked at risk factors for colonization. Nasal swabs were tested for MRSA on all admissions to the PICU from May 2008 to September 2009 using polymerase chain reaction as per hospital guidelines. All patients enrolled were placed in either a MRSA-positive or a MRSA-negative group, which were compared with each other. Risk factors were assessed from a questionnaire and the resident history. The prevalence of MRSA colonization in our study was 4.5%. Six hundred sixty-six patients were negative for MRSA, and 31 were positive. Patients in the MRSA colonization group were younger, more likely had family (household members) employed in medicine, and were more likely hospitalized or had undergone surgery within the previous 12 months. Prolonged neonatal intensive care unit stay (>1 week) was associated with MRSA colonization (P < .001). The percentage of patients positive for MRSA admitted to a PICU is low. Recent exposure to the health care system, especially a stay in the neonatal intensive care unit, is associated with an increased risk of colonization. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  11. Comparative effectiveness of hand-cleansing agents for removing methicillin-resistant Staphylococcus aureus from experimentally contaminated fingertips.

    PubMed

    Huang, Y; Oie, S; Kamiya, A

    1994-08-01

    Five subjects participated in a study of optimal conditions for removing methicillin-resistant Staphylococcus aureus from contaminated fingertips. Fingertips were contaminated experimentally and cleaned by various methods. Bacterial removal was measured as percentage and is given as mean +/- standard error of the mean. Rinsing the fingertips with tap water for 20 seconds and drying them with paper towels removed 95.2% +/- 1.6% of the contamination. Application of hand-cleansing agents to fingertips for 20 seconds, followed by a 20-second tap-water rinse and towel drying, removed bacteria as follows: povidone-iodine detergent, 99.2% +/- 0.4%; chlorhexidine detergent, 97.2% +/- 0.8%; and liquid soap, 96.1% +/- 1.1%. In a modification of the method, 80% ethyl alcohol applied to the fingertips for 20 seconds, followed by air drying for 40 seconds, removed 99.1% +/- 0.8% of the bacteria. Statistical analyses indicated that povidone-iodine and 80% ethyl alcohol were more effective than the other agents. Rinsing contaminated fingertips with tap water and towel drying them is sufficient to reduce contamination with methicillin-resistant S. aureus by 95%. Washing with povidone-iodine or 80% ethyl alcohol further reduces contamination by an additional 99%.

  12. Antibacterial activity of honey against community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA).

    PubMed

    Maeda, Yasunori; Loughrey, Anne; Earle, J A Philip; Millar, B Cherie; Rao, Juluri R; Kearns, Angela; McConville, Ogie; Goldsmith, Colin E; Rooney, Paul J; Dooley, James S G; Lowery, Colm J; Snelling, William J; McMahon, Ann; McDowell, David; Moore, John E

    2008-05-01

    Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has now been described globally, as a clinically significant pathogen, particularly associated with skin and soft tissue infections, including abscesses, cellulitis and furunculosis. The recent emergence of CA-MRSA combined with its predominant presentation associated with skin and soft tissue infection, the previous literature indicating honey as an effective treatment of healthcare-associated HA-MRSA-related wound infection, as well as honey's ease of topical application, make the current study timely and of interest to healthcare practitioners involved with wound management. Although previous studies have examined the antimicrobial activity of honey against HA-MRSA, such data are limited regarding the activity of honey against this emerging type of MRSA. CA-MRSA (n=6 isolates), was examined for its susceptibility to natural honey (n=3 honey produced from bees in Northern Ireland and one commercial French honey). Results demonstrated that all honey was able to reduce the cultural count of all CA-MRSA from approximately 10(6) colony-forming units (cfus) (mean = 6.46 log10 cfu/g) to none detectable within 24h of co-culture of separate CA-MRSA organisms individually with all four-honey types examined. Subsequent non-selective enrichment of honey demonstrated that inoculated honey remained positive for CA-MRSA until 72h postinoculation, after which point no culturable organisms could be detected. This study demonstrated that, in vitro, these natural products had an antimicrobial activity against the CA-MRSA organisms tested. Further studies are now required to demonstrate if this antimicrobial activity has any clinical application.

  13. Transmission Dynamics of Methicillin-Resistant Staphylococcus aureus in a Medical Intensive Care Unit in India

    PubMed Central

    Christopher, Solomon; Verghis, Rejina Mariam; Antonisamy, Belavendra; Sowmyanarayanan, Thuppal Varadachari; Brahmadathan, Kootallur Narayanan; Kang, Gagandeep; Cooper, Ben Symons

    2011-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) is a global pathogen and an important but seldom investigated cause of morbidity and mortality in lower and middle-income countries where it can place a major burden on limited resources. Quantifying nosocomial transmission in resource-poor settings is difficult because molecular typing methods are prohibitively expensive. Mechanistic statistical models can overcome this problem with minimal cost. We analyse the transmission dynamics of MRSA in a hospital in south India using one such approach and provide conservative estimates of the organism's economic burden. Methods and Findings Fifty months of MRSA infection data were collected retrospectively from a Medical Intensive Care Unit (MICU) in a tertiary hospital in Vellore, south India. Data were analysed using a previously described structured hidden Markov model. Seventy-two patients developed MRSA infections and, of these, 49 (68%) died in the MICU. We estimated that 4.2% (95%CI 1.0, 19.0) of patients were MRSA-positive when admitted, that there were 0.39 MRSA infections per colonized patient month (0.06, 0.73), and that the ward-level reproduction number for MRSA was 0.42 (0.08, 2.04). Anti-MRSA antibiotic treatment costs alone averaged $124/patient, over three times the monthly income of more than 40% of the Indian population. Conclusions Our analysis of routine data provides the first estimate of the nosocomial transmission potential of MRSA in India. The high levels of transmission estimated underline the need for cost-effective interventions to reduce MRSA transmission in hospital settings in low and middle income countries. PMID:21750700

  14. 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

  15. Novel antimicrobial peptide–modified azithromycin-loaded liposomes against methicillin-resistant Staphylococcus aureus

    PubMed Central

    Liu, Xiaowei; Li, Zhan; Wang, Xiaodong; Chen, Yujuan; Wu, Fengbo; Men, Ke; Xu, Ting; Luo, Yan; Yang, Li

    2016-01-01

    Infections caused by multidrug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), have become a public threat; therefore, development of new antimicrobial drugs or strategies is urgently required. In this study, a new antibacterial peptide DP7-C (Chol-suc-VQWRIRVAVIRK-NH2) and DP7-C-modified azithromycin (AZT)-loaded liposomes (LPs) are developed for the treatment of MRSA infection, and it was found that DP7-C inserted into the LP lipid bilayer not only functioned as a carrier to encapsulate the antibiotic AZT but also synergized the antibacterial effect of the encapsulated AZT. In vitro assays showed that DP7-C-modified LPs possessed sustained drug release profile and immune regulatory effect and did not show obvious cytotoxicity in mammal cells, but they did not possess direct antibacterial activity in vitro. In vivo studies revealed that DP7-C-modified LPs did not exhibit obvious side effects or toxicity in mice but were able to significantly reduce the bacterial counts in an MRSA-infectious mouse model and possessed high antibacterial activity. In particular, DP7-C-modified AZT-loaded LPs showed more positive therapeutic effects than either DP7-C-modified blank LPs or nonmodified AZT-loaded LPs treatment alone. Molecular mechanism studies demonstrated that DP7-C formulations effectively upregulated the production of anti-inflammatory cytokines and chemokines without inducing harmful immune response, suggesting that DP7-C was synergistic with AZT against the bacterial infection by activating the innate immune response. Most importantly, although DP7-C activated the innate immune response, it did not possess direct antibacterial activity in vitro, indicating that DP7-C did not possess the potential to induce bacteria resistance. The findings indicate that DP7-C-modified AZT-loaded LPs developed in this study have a great potential required for the clinical treatment of MRSA infections. PMID:28008253

  16. Control of Methicillin-Resistant Staphylococcus aureus Pneumonia Utilizing TLR2 Agonist Pam3CSK4

    PubMed Central

    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

  17. Predictors and clinical outcomes of persistent methicillin-resistant Staphylococcus aureus bacteremia: a prospective observational study.

    PubMed

    Ok, Hea Sung; Lee, Hyoun Soo; Park, Man Je; Kim, Ki Hoon; Kim, Byeong Ki; Wi, Yu Mi; Kim, June Myung

    2013-11-01

    The high mortality attributable to persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in spite of glycopeptide treatment has heightened the need for early detection and intervention with alternative agents. The purpose of this study was to determine the clinical characteristics of and risk factors for persistent MRSA bacteremia. All first episodes of significant MRSA bacteremia at a 710-bed academic medical center from November 2009 through August 2010 were recorded. Blood cultures were conducted at 3 days and every 2 to 3 days thereafter until clearance. Clinical characteristics and outcomes were compared between persistent MRSA bacteremia (≥ 7 days) and nonpersistent MRSA bacteremia (≤ 3 days). Of 79 patients with MRSA bacteremia during the study period, 31 (39.2%) had persistent MRSA bacteremia. The persistent MRSA bacteremia group had significantly higher 30-day mortality than the nonpersistent MRSA bacteremia group (58.1% vs. 16.7%, p < 0.001). Multivariate analysis indicated that metastatic infection at presentation (odds ratio [OR], 14.57; 95% confidence interval [CI], 3.52 to 60.34; p < 0.001) and delayed catheter removal in catheter-related infection (OR, 3.80; 95% CI, 1.04 to 13.88; p = 0.004) were independent predictors of persistent MRSA bacteremia. Patients with a time to blood culture positivity (TTP) of < 11.8 hours were at increased risk of persistent MRSA bacteremia (29.0% vs. 8.3%, p = 0.029). High mortality in patients with persistent MRSA bacteremia was noted. Early detection of metastatic infection and early removal of infected intravascular catheters should be considered to reduce the risk of persistent MRSA bacteremia. Further studies are needed to evaluate the role of TTP for predicting persistent MRSA bacteremia.

  18. Methicillin-Resistant Staphylococcus aureus in Saarland, Germany: A Statewide Admission Prevalence Screening Study

    PubMed Central

    Herrmann, Mathias; Petit, Christine; Dawson, Alik; Biechele, Judith; Halfmann, Alexander; von Müller, Lutz; Gräber, Stefan; Wagenpfeil, Stefan; Klein, Renate; Gärtner, Barbara

    2013-01-01

    Background The screening of hospital admission patients for methicillin resistant Staphylococcus aureus (MRSA) is of undisputed value in controlling and reducing the overall MRSA burden; yet, a concerted parallel universal screening intervention throughout all hospitals of an entire German Federal State has not yet been performed. Methodology/Principal Findings During a four-week period, all 24 acute care hospitals of the State of Saarland participated in admission prevalence screening. Overall, 436/20,027 screened patients revealed MRSA carrier status (prevalence, 2.2/100 patients) with geriatrics and intensive care departments associated with highest prevalence (7.6/100 and 6.3/100, respectively). Risk factor analysis among 17,975 admission patients yielded MRSA history (OR, 4.3; CI95 2.7–6.8), a skin condition (OR, 3.2; CI95 2.1–5.0), and/or an indwelling catheter (OR, 2.2; CI95 1.4–3.5) among the leading risks. Hierarchical risk factor ascertainment of the six risk factors associated with highest odd’s ratios would require 31% of patients to be laboratory screened to allow for detection of 67% of all MRSA positive admission patients in the State. Conclusions/Significance State-wide admission prevalence screening in conjunction with risk factor ascertainment yields important information on the distribution of the MRSA burden for hospitals, and allows for data-based decisions on local or institutional MRSA screening policies considering risk factor prevalence and expected MRSA identification rates. PMID:24040103

  19. Vancomycin tolerant, methicillin-resistant Staphylococcus aureus reveals the effects of vancomycin on cell wall thickening.

    PubMed

    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.

  20. 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

  1. Establishment of a new methicillin resistant Staphylococcus aureus animal model of osteomyelitis.

    PubMed

    Helbig, Lars; Simank, Hans Georg; Lorenz, Helga; Putz, Cornelia; Wölfl, Christoph; Suda, Arnold J; Moghaddam, Arash; Schmidmaier, Gerhard; Guehring, Thorsten

    2014-04-01

    The increase in methicillin-resistant Staphylococcus aureus (MRSA) infections is currently a major health care problem. Vancomycin is still often the first-line anti-microbiological agent for treating such infections; however, a recent decline in efficacy of vancomycin in MRSA infections has raised concerns and accelerated the search for new antibiotics. The aim of this study was to establish a MRSA peri-implant osteomyelitis animal model for future testing of new anti-microbiological agents under typical MRSA infection conditions. Eighteen randomised NZW-rabbits underwent a standardised surgical procedure with the insertion of a femoral bone implant. Animals were then divided into group 1 (MRSA inoculation, no antibiotics; M/N), group 2 (MRSA inoculation, Vancomyin; M/V), and group 3 (no MRSA inoculation, no antibiotics; N/N). The primary study outcome parameters were animal leucocyte count, animal weight, and animal body temperature at one, seven, and 42 days after surgery. Additionally, a histo-morphometrical score was established and adjusted to a modified histological Smeltzer score. Macroscopic and histo-morphometrical findings showed a peri-implant osteomyelitis in group 1 with both increased acute and chronic infection parameters in M/N, as compared to M/V and N/N, indicating that vancomycin treatment prevented typical morphological changes of MRSA peri-implant osteomyelitis. Similarly, there was a reduction in animal weight and increase in leucocyte count and body temperature in group 1 (each p < 0.005). Vancomycin treatment again resulted in significantly reduced leucocyte count and body temperature, and increased animal body weight. Here we have established a peri-implant MRSA osteomyelitis model that successfully combined clinical and laboratory outcome parameters of infection with histo-morphometrical results; this model appears to be valuable for future experimental use and therapeutic monitoring of new anti-microbiological MRSA drugs.

  2. Antimicrobial susceptibilities of health care-associated and community-associated strains of methicillin-resistant Staphylococcus aureus from hospitalized patients in Canada, 1995 to 2008.

    PubMed

    Simor, Andrew E; Louie, Lisa; Watt, Christine; Gravel, Denise; Mulvey, Michael R; Campbell, Jennifer; McGeer, Allison; Bryce, Elizabeth; Loeb, Mark; Matlow, Anne

    2010-05-01

    We determined the in vitro antimicrobial susceptibilities of 7,942 methicillin-resistant Staphylococcus aureus (MRSA) isolates obtained from patients hospitalized in 48 Canadian hospitals from 1995 to 2008. Regional variations in susceptibilities were identified. The dissemination of community-associated strains in Canada appears to have contributed to increased susceptibility of MRSA to several non-beta-lactam antimicrobial agents in the past decade. Reduced susceptibility to glycopeptides was not identified.

  3. Evaluation of an alcohol-based power sanitizing system for decontamination of hospital rooms of patients with methicillin-resistant Staphylococcus aureus carriage.

    PubMed

    Jury, Lucy A; Cadnum, Jennifer L; Jennings-Sanders, Andrea; Eckstein, Elizabeth C; Chang, Shelley; Donskey, Curtis J

    2010-04-01

    A power sanitizing system that delivers a sanitizing mist of alcohol, rendered nonflammable by a carbon dioxide carrier, and a low concentration of quaternary ammonium compound, was easy to use, provided thorough coverage of surfaces, and significantly reduced vancomycin-resistant Enterococcus and methicillin-resistant Staphylococcus aureus contamination on commonly touched hospital surfaces. However, it was not as consistently effective for elimination of pathogens as 10% bleach solution. Published by Mosby, Inc.

  4. Evaluation of cefoxitin disk diffusion breakpoint for detection of methicillin resistance in Staphylococcus pseudintermedius isolates from dogs.

    PubMed

    Bemis, David A; Jones, Rebekah D; Videla, Ricardo; Kania, Stephen A

    2012-09-01

    Cefoxitin disk diffusion susceptibility testing is a recommended screening method for the detection of methicillin resistance in human isolates of Staphylococcus aureus and coagulase-negative staphylococci. A retrospective analysis of 1,146 clinical isolates of Staphylococcus pseudintermedius from dogs was conducted to determine if screening by the cefoxitin disk method can be similarly useful with S. pseudintermedius. The distribution of cefoxitin growth inhibition zone diameters within this collection was bimodal and correlated well with the results of methicillin resistance gene (mecA) detection by polymerase chain reaction. Of the isolates, 5% had discordant results and, when retested, 84% of these were in agreement. While a greater diversity of isolates and interlaboratory comparisons must be tested, the current study suggests that an epidemiological breakpoint (of approximately ≤ 30 mm = resistant; ≥ 31 = susceptible) can be established to predict methicillin resistance in S. pseudintermedius.

  5. In vitro activity of retapamulin against linezolid and methicillin-resistant Staphylococcus aureus isolates.

    PubMed

    Candel, F J; Morales, G; Picazo, J J

    2011-09-01

    To determine the in vitro activity of retapamulin and other topical antibiotics (mupirocin, bacitracin, and fusidic acid) usually employed for nasal decolonization, against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), and linezolid and methicillin-resistant S. aureus. The minimum inhibitory concentrations (MICs) were determined on Mueller-Hinton agar according to the guidelines of the Clinical and Laboratory Standards Institute and of the European Committee for Antimicrobial Susceptibility Testing. Presence of the cfr gene in linezolid and methicillin-resistant S. aureus isolates was detected using polymerase chain reaction. Retapamulin inhibited all the isolates of MSSA and MRSA at 0.125 mg/L, but the 18 linezolid-resistant-MRSA strains proved resistant, with MICs over 32 mg/L. Most MSSA isolates (9/10) were susceptible to mupirocin with MICs under 0.19 mg/L, although this value decreased to half against MRSA, and almost all linezolid-resistant MRSA (17/18) strains were resistant to mupirocin with an MIC range of between 8 mg/L and 28 mg/L. The MIC of fusidic acid increased substantially against linezolid-resistant MRSA, whereas that of bacitracin showed no differences. Retapamulin demonstrated excellent in vitro activity against MSSA and MRSA strains, but not against MRSA isolates harbouring the cfr gene. The results of this in vitro study support cut-off values for retapamulin of ≤ 0.5, 1, and ≥ 2 mg/L for susceptible, intermediate, and resistant strains, respectively.

  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. Distribution and drug resistance profile of methicillin-resistant Staphylococcus aureus after orthopaedic surgery.

    PubMed

    Song, Wen Chao; Zhang, Si Sen; Gong, Yu Hong

    2015-05-01

    This paper is aimed to comprehend clinical distribution and drug-resistance situation of methicillin-resistant Staphylococcus aureus. This study applied automatic microbe instrument Microscan W/A 96 for strain identification and drug susceptibility screening on the isolated strains. It was found that 312 MRSA strains were isolated in three years, which account for 58.1% of Staphylococcus aureus. MRSA were mainly focused in wound secretion, purulent sputum and prostatic fluid and a few of them were isolated from blood specimens; Endemic area distribution was mainly located in intensive care unit, neurosurgery, respiratory department, dermatology, orthopaedic burns and orthopaedics. MRSA strains showed high drug resistance of 82.37%~100% to most of the antibiotics including vancomycin, cotrimoxazole and rifampicin. Strain was 100% resistance towards ampicillin, amoxicillin/acid, cefalotin, cefazolin, tienam, benzylpenicillin, penicillin and tetracycline and 90% strains resisted clindamycin, cefotaxime, clarithromycin and gentamicin.

  8. Risk factors associated with methicillin-resistant Staphylococcus aureus infection in children.

    PubMed

    Senthilkumar, Kandasamy; Biswal, Niranjan; Sistla, Sujatha

    2015-01-01

    To identify the clinical variables that differentiate MRSA (Methicillin-resistant Staphylococcus aureus) from MSSA (Methicillin-sensitive S. aureus) infection. Cases having culture isolates of Staphylococcus species were recruited. Baseline and other laboratory parameters were compared between MSSA and MRSA sub-groups to identify the predictors for MRSA. Out of 98 isolates of S.aureus, 46 (47%) were MRSA. Significant leukocytosis was found in cases with MRSA (P

  9. 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.

  10. Mortality among critically ill patients with methicillin-resistant Staphylococcus aureus bacteremia: a multicenter cohort study in Colombia.

    PubMed

    Castillo, Juan S; Leal, Aura L; Cortes, Jorge A; Alvarez, Carlos A; Sanchez, Ricardo; Buitrago, Giancarlo; Barrero, Liliana I; Gonzalez, Andrés L; Henriquez, Daibeth H

    2012-11-01

    To evaluate risk factors associated with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia emergence, its prognosis, and mortality-determining factors in critically ill patients in Colombia. A multicenter, retrospective cohort study conducted in 2005-2008 at 16 public and private reference health care institutions in Bogotá, Colombia, that form part of a national epidemiological surveillance network and a hospital network with 4 469 beds. Methicillin-resistant emergence and mortality were analyzed using descriptive and time-to-event analysis; a multivariate Cox proportional hazard regression model was built to test the association between methicillin resistance and mortality. A total of 372 patients were studied: 186 with MRSA bacteremia, randomly matched with 186 with methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. Previous surgery, antibiotic exposure, and hospital-acquired infections were independently associated with methicillin resistance. MRSA caused longer hospital stays among survivors (median 24 versus 18 days, P = 0.014). Mortality predictors were: patient age, creatinine level over 1.21 mg/dl at ICU admission, severe sepsis, and inotropic requirement. Appropriate antimicrobial therapy and antimicrobial therapy change were independent protective factors, as was male gender. Methicillin resistance per se was not a mortality-independent prognostic factor. Previous conditions, such as age, baseline renal impairment, severe sepsis, and inotropy demand explained the observed mortality. Appropriate antimicrobial therapy remained a protective factor. A call to improve infection control measures in Colombia is mandatory.

  11. Telavancin demonstrates activity against methicillin-resistant Staphylococcus aureus isolates with reduced susceptibility to vancomycin, daptomycin, and linezolid in broth microdilution MIC and one-compartment pharmacokinetic/pharmacodynamic models.

    PubMed

    Smith, Jordan R; Barber, Katie E; Hallesy, Jessica; Raut, Animesh; Rybak, Michael J

    2015-09-01

    Methicillin-resistant Staphylococcus aureus (MRSA) isolates have arisen with reduced susceptibility to several anti-MRSA agents. Telavancin (TLV), a novel anti-MRSA agent, retains low MICs against these organisms. Our objective was to determine the MICs for TLV, daptomycin (DAP), vancomycin (VAN), and linezolid (LZD) against daptomycin-nonsusceptible (DNS) S. aureus, vancomycin-intermediate S. aureus (VISA), heteroresistant VISA (hVISA), and linezolid-resistant (LZD(r)) S. aureus. We also evaluated these agents against each phenotype in pharmacokinetic/pharmacodynamic (PK/PD) models. Seventy DNS, 100 VISA, 180 hVISA, and 25 LZD(r) MRSA isolates were randomly selected from our library and tested to determine their MICs against TLV, DAP, VAN, and LZD via broth microdilution and a Trek panel. Four isolates were randomly selected for 168-h in vitro models to evaluate treatment with TLV at 10 mg/kg of body weight/day, DAP at 10 mg/kg/day, VAN at 1 g every 12 h (q12h), and LZD at 600 mg q12h. The MIC50/90 for TLV, DAP, VAN, and LZD against 70 DNS S. aureus isolates were 0.06/0.125 μg/ml, 2/4 μg/ml, 1/2 μg/ml, and 2/2 μg/ml, respectively. Against 100 VISA isolates, the MIC50/90 were 0.06/0.125 μg/ml, 1/1 μg/ml, 4/8 μg/ml, and 1/2 μg/ml, respectively. Against 170 hVISA isolates, the MIC50/90 were 0.06/0.125 μg/ml, 0.5/1 μg/ml, 1/2 μg/ml, and 1/2 μg/ml, respectively. Against 25 LZD(r) isolates, the MIC50/90 were 0.03/0.06 μg/ml, 1/1 μg/ml, 2/2 μg/ml, and 8/8 μg/ml, respectively. The TLV MIC was >0.125 μg/ml for 10/365 (2.7%) isolates. In PK/PD models, TLV was universally bactericidal at 168 h and statistically superior to all antibiotics against DNS S. aureus strain R2334. These data further establish the potency of TLV against resistant MRSA. The model data demonstrate in vitro bactericidal activity of TLV against hVISA, VISA, DNS S. aureus, and LZD(r) S. aureus strains. Further clinical research is warranted. Copyright © 2015, American Society for

  12. Staphylococcus aureus CC398: host adaptation and emergence of methicillin resistance in livestock.

    PubMed

    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; Zmudzki, 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

    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. Modern food animal production is characterized by densely concentrated animals and routine antibiotic use, which may facilitate the emergence of novel antibiotic-resistant zoonotic pathogens. Our findings strongly support the idea

  13. Methicillin-resistant Staphylococcus pseudintermedius among dogs admitted to a small animal hospital.

    PubMed

    Nienhoff, Ulrike; Kadlec, Kristina; Chaberny, Iris F; Verspohl, Jutta; Gerlach, Gerald-F; Kreienbrock, Lothar; Schwarz, Stefan; Simon, Daniela; Nolte, Ingo

    2011-05-12

    The aim of this study was to determine the frequency of carriage of methicillin-resistant Staphylococcus pseudintermedius (MRSP) among dogs admitted to a small animal hospital during a 17-month period, to characterize these isolates and to initially screen for possible factors associated with MRSP carriage. Swabs were taken from the nose/pharynx and the perineum as well as from wounds and skin infections (if present) of 814 dogs before entering the small animal hospital. A questionnaire for background information was completed. The staphylococcal species and methicillin resistance were confirmed pheno- and genotypically. The identified MRSP isolates were characterized by SCCmec typing, testing for susceptibility to 25 antimicrobial agents and SmaI-directed pulsed-field gel electrophoresis. A first screening for possible risk factors for MRSP carriage was performed by means of unifactorial contingency tables and CART analysis. Sixty (7.4%) dogs were positive for MRSP. All MRSP isolates harboured a type II-III SCCmec cassette and showed extended resistance to antimicrobial agents. Fifteen different SmaI patterns were observed. The major factors that clustered with MRSP carriage were former hospitalization and antibiotic treatment within the last six months before sampling. This study showed that only a minor part of the sampled dogs carried multi-resistant MRSP isolates. The facts that prior hospitalization and/or antibiotic therapy are potential associated factors for MRSP carriage underline the necessity of a judicious use of antibiotics in small animal medicine.

  14. 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.

  15. 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.

  16. Detection and identification of methicillin resistant and sensitive strains of Staphylococcus aureus using tandem measurements.

    PubMed

    Guntupalli, Rajesh; Sorokulova, Iryna; Olsen, Eric; Globa, Ludmila; Pustovyy, Oleg; Moore, Timothy; Chin, Bryan; Barbaree, James; Vodyanoy, Vitaly

    2012-09-01

    Discrimination of methicillin resistant (MRSA) and sensitive (MSSA) strains of Staphylococcus aureus, was achieved by the specially selected lytic bacteriophage with a wide host range of S. aureus strains and a penicillin-binding protein (PBP 2a) specific antibody. A quartz crystal microbalance with dissipation monitoring (QCM-D) was employed to analyze bacteria-phage interactions. The lytic phages were transformed into phage spheroids by exposure to water-chloroform interface. Phage spheroid monolayers were transferred onto QCM-D sensors by Langmuir-Blodgett (LB) technique. Biosensors were tested in the flow mode with bacterial water suspensions, while collecting frequency and energy dissipation changes. Bacteria-spheroid interactions resulted in decreased resonance frequency and an increase in dissipation energy for both MRSA and MSSA strains. Following the bacterial binding, these sensors were further exposed to a flow of the penicillin-binding protein (PBP 2a) specific antibody conjugated latex beads. Sensors tested with MRSA responded to PBP 2a antibody beads; while sensors examined with MSSA gave no response. This experimental difference establishes an unambiguous discrimination between methicillin resistant and sensitive S. aureus strains. Both free and immobilized bacteriophages strongly inhibit bacterial growth on solid/air interfaces and in water suspensions. After lytic phages are transformed into spheroids, they retain their strong lytic activity and demonstrate high bacterial capture efficiency. The phage and phage spheroids can be used for screening and disinfection of antibiotic resistant bacteria. Other applications may include use on biosensors, bacteriophage therapy, and antimicrobial surfaces.

  17. Evolutionary Models of the Emergence of Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Robinson, D. Ashley; Enright, Mark C.

    2003-01-01

    Five major lineages of methicillin-resistant Staphylococcus aureus (MRSA) have evolved since the introduction of methicillin for the treatment of infections caused by penicillin-resistant S. aureus in 1959. The clones of these lineages are responsible for the vast majority of hospital-acquired MRSA disease globally. We have constructed high-resolution evolutionary models for each lineage using a parsimony approach with 15 partial gene sequences from 147 geographically diverse isolates. On the basis of these models, we infer that MRSA has emerged at least 20 times upon acquisition of the methicillin resistance determinant, which is carried on a mobile genetic element called the staphylococcal cassette chromosome mec (SCCmec). The acquisition of SCCmec by sensitive clones was four times more common than the replacement of one SCCmec with another. Notably, SCCmec type IV was found in twice as many clones as any other SCCmec type, and it is this SCCmec type which is commonly found in clones from patients with community-acquired MRSA disease. Our findings suggest that most clones of MRSA arise by the acquisition of SCCmec type IV by methicillin-sensitive isolates. PMID:14638503

  18. [Nasal carriers of methicillin-resistant Staphylococcus aureus among cuban children attending day-care centers].

    PubMed

    Toraño, G; Quiñones, D; Hernández, I; Hernández, T; Tamargo, I; Borroto, S

    2001-10-01

    Recent but scarce reports of methicillin-resistant Staphylococcus aureus strains (MRSA) among children without risk factors associated with its acquisition prompted us to investigate its presence in the community. During the September and October months in 1997, nasal and pharyngeal swabs were obtained from 358 children aged less than five years who attended three day-care centers in the Marianao Area, La Habana City, Cuba. The isolated S. aureus strains were characterized for antimicrobial sensitivity using the Kirby-Bauer method. Methicillin resistance was confirmed by te Oxacillin Salt-Agar Screening-Plate method recommended by the National Committee for Clinical Laboratory Standards. 18.7% of children were carriers of S. aureus in the upper respiratory tract; 2.2% of children carried MRSA strains. The highest resistance levels corresponded to erythromycin (50.74%) and tetracycline (29.9%). All tested strains were sensitive to ciprofloxacin. Our results provide evidence on the recovery of MRSA strains among healthy children attending day-care centers and are suggestive of a rapid colonization and spread of these microorganisms in the community.

  19. 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.

  20. 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.

  1. ANTISTAPHYBASE: database of antimicrobial peptides (AMPs) and essential oils (EOs) against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus.

    PubMed

    Zouhir, Abdelmajid; Taieb, Malek; Lamine, Mohamed Ashraf; Cherif, Ammar; Jridi, Taoufik; Mahjoubi, Basma; Mbarek, Sarra; Fliss, Ismail; Nefzi, Adel; Sebei, Khaled; Ben Hamida, Jeannette

    2017-03-01

    Staphylococcus aureus and methicillin-resistant S. aureus are major pathogens. The antimicrobial peptides and essential oils (EOs) display narrow- or broad-spectrum activity against bacteria including these strains. A centralized resource, such as a database, designed specifically for anti-S. aureus/anti-methicillin-resistant S. aureus antimicrobial peptides and EOs is therefore needed to facilitate the comprehensive investigation of their structure/activity associations and combinations. The database ANTISTAPHYBASE is created to facilitate access to important information on antimicrobial peptides and essential peptides against methicillin-resistant S. aureus and S. aureus. At the moment, the database contains 596 sequences of antimicrobial peptides produced by diverse organisms and 287 essential oil records. It permits a quick and easy search of peptides based on their activity as well as their general, physicochemical properties and literature data. These data are very useful to perform further bioinformatic or chemometric analysis and would certainly be useful for the development of new drugs for medical use. The ANTISTAPHYBASE database is freely available at: https://www.antistaphybase.com/ .

  2. USA300 genotype community-associated methicillin-resistant Staphylococcus aureus as a cause of surgical site infections.

    PubMed

    Patel, Mukesh; Kumar, Ritu A; Stamm, Alan M; Hoesley, Craig J; Moser, Stephen A; Waites, Ken B

    2007-10-01

    Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains are increasingly recovered from nosocomial settings. We conducted a retrospective study of surgical site infections (SSI) during 2004 and 2005 to determine the prevalence of CA-MRSA; 57% of MRSA strains tested belonged to the USA300 genotype. CA-MRSA has become a prominent cause of SSI at our institution.

  3. 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.

  4. Potential Role of Pet Animals in Household Transmission of Methicillin-Resistant Staphylococcus aureus: A Narrative Review

    PubMed Central

    Bramble, Manuel; Morris, Daniel; Tolomeo, Pam

    2011-01-01

    Abstract 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

  5. 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.

  6. Whole Genome Sequencing of a Methicillin-Resistant Staphylococcus aureus Pseudo-Outbreak in a Professional Football Team

    PubMed Central

    Anderson, Deverick J.; Harris, Simon R.; Godofsky, Eliot; Toriscelli, Todd; Rude, Thomas H.; Elder, Kevin; Sexton, Daniel J.; Pellman, Elliot J.; Mayer, Thom; Fowler, Vance G.; Peacock, Sharon J.

    2014-01-01

    Two American football players on the same team were diagnosed with methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections on the same day. Our investigation, including whole genome sequencing, confirmed that players did not transmit MRSA to one another nor did they acquire the MRSA from a single source within the training facility. PMID:25734164

  7. Draft Genome Sequence of Methicillin-Resistant Staphylococcus aureus Strain LC33 Isolated from Human Breast Milk

    PubMed Central

    de Almeida, Jéssica B.; de Carvalho, Suzi P.; de Freitas, Leandro M.; Guimarães, Ana Marcia S.; do Nascimento, Naíla C.; dos Santos, Andrea P.; Messick, Joanne B.; Timenetsky, Jorge

    2017-01-01

    ABSTRACT Here, we report the draft genome sequence of Staphylococcus aureus strain LC33, isolated from human breast milk in Brazil. This microorganism has been typed as ST1/t127/sccmecV. To our knowledge, this is the first draft genome sequence of a methicillin-resistant S. aureus strain isolated from human breast milk. PMID:28408673

  8. Vancomycin-intermediate livestock-associated methicillin-resistant Staphylococcus aureus ST398/t9538 from swine in Brazil.

    PubMed

    Moreno, Luisa Z; Dutra, Mauricio C; Moreno, Marina; Ferreira, Thais Sp; Silva, Givago Fr da; Matajira, Carlos Ec; Silva, Ana Paula S; Moreno, Andrea M

    2016-10-01

    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.

  9. Use of variations in staphylococcal interspersed repeat units for molecular typing of methicillin-resistant Staphylococcus aureus strains.

    PubMed

    Hardy, Katherine J; Oppenheim, Beryl A; Gossain, Savita; Gao, Fang; Hawkey, Peter M

    2006-01-01

    Staphylococcal interspersed repeat unit typing has previously been shown to have the ability to discriminate between epidemic methicillin-resistant Staphylococcus aureus strains in the United Kingdom. The current study illustrates its ability to distinguish between strains within an endemic setting thereby providing a rapid transportable typing method for the identification of transmission events.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  11. Complete genome sequence of livestock associated methicillin resistant Staphylococcus aureus ST398 isolated from swine in USA

    USDA-ARS?s Scientific Manuscript database

    Methicillin resistant Staphylococcus aureus colonizes and causes disease in many animal species. Livestock associated-MRSA isolates are represented by isolates of the sequence type 398. These isolates are considered to be livestock adapted. This report provides the complete genome of one swine assoc...

  12. Methicillin-resistant Staphylococcus aureus infection in a college football team: risk factors outside the locker room and playing field.

    PubMed

    Archibald, Lennox K; Shapiro, Jerne; Pass, Anthony; Rand, Kenneth; Southwick, Frederick

    2008-05-01

    We investigated a cluster of methicillin-resistant Staphylococcus aureus infections in college football players. Risk factors included a history of recurrent skin infections and contact with the skin lesions of persons outside college. The infections were controlled through treatment of carriers with topical mupirocin, chlorhexidine body washes, and enhancement of personal hygiene practices. Varsity and professional teams need to consider similar preventive measures.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  14. Alternative Use for Spectra MRSA Chromogenic Agar in Detection of Methicillin-Resistant Staphylococcus aureus from Positive Blood Cultures ▿

    PubMed Central

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

    2010-01-01

    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. PMID:20392925

  15. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  17. Antimicrobial susceptibility and methicillin resistance in Staphylococcus pseudintermedius and Staphylococcus schleiferi subsp. coagulans isolated from dogs with pyoderma in Japan.

    PubMed

    Kawakami, Tetsuji; Shibata, Sanae; Murayama, Nobuo; Nagata, Masahiko; Nishifuji, Koji; Iwasaki, Toshiroh; Fukata, Tsuneo

    2010-12-01

    To understand species distribution, trends of antimicrobial susceptibility and prevalence of methicillin resistance in canine staphylococci in Japan, 190 coagulase-positive staphylococci (CoPS) were isolated from dogs with pyoderma in 2 Japanese veterinary referral hospitals. Using a multiplex polymerase chain reaction (M-PCR) method, two CoPS species were identified: 170 Staphylococcus pseudintermedius (89.5%) and 20 S. schleiferi subsp. coagulans isolates (10.5%). In these isolates, susceptibility to 7 antimicrobial agents was determined. Overall, the levels of susceptibility to cefalexin (CEX), amoxicillin/clavulanic acid (CVA/AMPC), minocycline (MINO), ofloxacin (OFLX), norfloxacin (NFLX), lincomycin (LCM) and clindamycin (CLDM) in S. pseudintermedius isolates were 38.2, 52.4, 34.7, 31.2, 34.1, 1.2 and 11.2%, respectively. In S. schleiferi subsp. coagulans isolates, 55% demonstrated susceptibility to CEX, 80% to CVA/AMPC, 70% to MINO, 45% to OFLX or NFLX and 30% to CLDM. None of S. schleiferi subsp. coagulans isolates was susceptible to LCM. To determine the prevalence of methicillin-resistant strains, we used a PCR method, which enabled detection of the fragment of mecA gene in 66.5% (113 of 170) in S. pseudintermedius and 30.0% (6 of 20) in S. schleiferi subsp. coagulans isolates. The frequencies of susceptibility to CEX, CVA/AMPC, OFLX, NFLX and CLDM were significantly lower in methicillin-resistant CoPS than in methicillin-susceptible CoPS isolates. These data suggest a high level of methicillin resistance in staphylococci isolated from dogs with pyoderma in Japan.

  18. [Surveillance and control of methicillin-resistant Staphylococcus aureus in Spanish hospitals. A GEIH-SEIMC and SEMPSPH consensus document].

    PubMed

    Rodríguez-Baño, Jesús; Bischofberger, Cornelia; Alvarez-Lerma, Francisco; Asensio, Angel; Delgado, Teresa; García-Arcal, Dolores; García-Ortega, Lola; Hernández, M Jesús; Molina-Cabrillana, Jesús; Pérez-Canosa, Carmen; Pujol, Miquel

    2008-05-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen, both in-hospital and in the community. Although there are several guidelines with recommendations for the control of this microorganism, the measures proposed are not uniformly implemented in Spanish hospitals. The objective of this document is to provide evidence-based recommendations that are applicable to Spanish hospitals, with the aim of reducing transmission of MRSA in our health care centers. The recommendations are divided into the following groups: surveillance, active detection of colonization in patients and health care workers, control measures for colonized or infected patients, decolonization therapy, environmental cleaning and disinfection, antimicrobial consumption, measures for non-hospitalized patients, and others. The main measures recommended include appropriate surveillance, hand hygiene, and implementation of active surveillance, contact precautions, and environmental cleaning.

  19. Antimicrobial activity and synergism of Sami-Hyanglyun-Hwan with ciprofloxacin against methicillin-resistant Staphylococcus aureus.

    PubMed

    Choi, Jang-Gi; Choi, Ji-Young; Mun, Su-Hyun; Kang, Ok-Hwa; Bharaj, Preeti; Shin, Dong-Won; Chong, Myong-Soo; Kwon, Dong-Yeul

    2015-07-01

    To investigate the antibacterial activity of SHH extracted with either water or ethanol against methicillin-resistant Staphylococcus aureus (MRSA) and combinatory antimicrobial effect with ciprofloxacin (CIP) by time kill assay and checkerboard dilution test. The antibacterial activity determined by broth dilution method indicated that the antibacterial activity of Sami-Hyanglyun-Hwan (SHH) water extract (SHHW) and SHH ethanol extract (SHHE) ranged from 250 to 2000 μg/mL and 125 to 1000 μg/mL against MRSA, respectively. In the checkerboard method, the combinations of SHHE with CIP had a partial synergistic or synergistic effect against MRSA. The time-kill curves showed that a combined SHHE and CIP treatment reduced the bacterial counts dramatically after 24 h. The present study demonstrates the therapeutic ability of SHHE against MRSA infections. Copyright © 2015 Hainan Medical College. Production and hosting by Elsevier B.V. All rights reserved.

  20. RNA-Seq-based transcriptome analysis of methicillin-resistant Staphylococcus aureus biofilm inhibition by ursolic acid and resveratrol

    PubMed Central

    Qin, Nan; Tan, Xiaojuan; Jiao, Yinming; Liu, Lin; Zhao, Wangsheng; Yang, Shuang; Jia, Aiqun

    2014-01-01

    Bacterial biofilms are particularly problematic since they become resistant to most available antibiotics. Hence, novel potential antagonists to inhibit biofilm formation are urgent. Here the influences of two natural products, ursolic acid and resveratrol, on biofilm of the clinical methicillin-resistant Staphylococcus aureus (MRSA) isolate were investigated using RNA-seq, and the differentially expressed genes were analyzed using Cuffdiff. The results showed that ursolic acid inhibition of biofilm formation may reduce amino acids metabolism and adhesins expression and resveratrol may disturb quorum sensing (QS) and the synthesis of surface proteins and capsular polysaccharides. In addition, the transcriptome analysis of resveratrol and the combination of resveratrol with vancomycin inhibition of established biofilm revealed that resveratrol would disturb the expression of genes related to QS, surface and secreted proteins, and capsular polysaccharides. These findings suggest that ursolic acid and resveratrol could be useful to be adjunct therapies for the treatment of MRSA biofilm-involved infections. PMID:24970710

  1. Occurrence of methicillin-resistant and -susceptible Staphylococcus aureus within a single colony contributing to MRSA mis-identification.

    PubMed

    Falcão, M H; Texeira, L A; Ferreira-Carvalho, B T; Borges-Neto, A A; Figueiredo, A M

    1999-06-01

    Many methods have been described for the detection of methicillin-resistant Staphylococcus aureus (MRSA), but the homogeneous or heterogeneous expression of methicillin resistance affects the reliability of those methods. This study demonstrates that close association between methicillin-susceptible S. aureus (MSSA) and MRSA strains in the host colonisation site can present additional problems for the detection of MRSA in clinical laboratories, which may contribute to failure in the control of MRSA infection in hospital. Worse, this association may also account for the emergence of MRSA during antibiotic therapy.

  2. Molecular and phenotypic characterization of methicillin-resistant Staphylococcus aureus isolates causing bacteremia at a major hospital in southern Mississippi.

    PubMed

    Samanta, Dhritiman; Batte, Justin L; Brown, Stephanie N; Crosby, Angela G; Marcos, Luis A; Elasri, Mohamed O

    2015-05-01

    Staphylococcus aureus is the predominant cause of bacteremia worldwide. We assessed the molecular epidemiology and antibiotic resistance of methicillin-resistant S aureus isolates causing bacteremia in southern Mississippi. Diverse genetic backgrounds in terms of staphylococcal cassette chromosome mec, pulsed-field gel electrophoresis, and multilocus sequence typing types of methicillin-resistant S aureus were identified as causing bacteremia in Mississippi. A strong association of Panton-Valentine leukocidin genes with elevated vancomycin minimum inhibitory concentration is one of the important findings of our study.

  3. Correlation of Minimum Inhibitory Concentration Breakpoints and Methicillin Resistance Gene Carriage in Clinical Isolates of Staphylococcus epidermidis.

    PubMed

    Eftekhar, Fereshteh; Raei, Fereshteh

    2011-09-01

    Staphylococcus epidermidis is the most important member of coagulase negative staphylococci responsible for community and hospital acquired infections. Most clinical isolates of S. epidermidis are resistant to methicillin making these infections difficult to treat. In this study, correlation of methicillin resistance phenotype was compared with methicillin resistance (mecA) gene carriage in 55 clinical isolates of S. epidermidis. Susceptibility was measured by disc diffusion using methicillin discs, and minimum inhibitory concentrations (MIC) were measured using broth microdilution. Methicillin resistance gene (MecA gene) carriage was detected by specific primers and PCR. Disc susceptibility results showed 90.9% resistance to methicillin. Considering a MIC of 4 µg/ml, 78.1% of the isolates were methicillin resistant, 76.36% of which carried the mecA gene. On the other hand, when a breakpoint of 0.5 µg/ml was used, 89.09% were methicillin resistant, of which 93.75% were mecA positive. There was a better correlation between MIC of 0.5 µg/ml with disc diffusion results and mecA gene carriage. The findings suggest that despite the usefulness of molecular methods for rapid diagnosis of virulence genes, gene carriage does not necessarily account for virulence phenotype. Ultimately, gene expression, which is controlled by the environment, would determine the outcome.

  4. Lack of increase in time to blood culture positivity in a patient with persistent methicillin-resistant Staphylococcus aureus bacteremia predicts failure of antimicrobial therapy.

    PubMed

    Liao, Chun-Hsing; Huang, Yu-Tsung; Chu, Fang-Yeh; Lin, Tsui-Hsien; Hsueh, Po-Ren

    2008-08-01

    Time to positivity is an available parameter in automated blood culture systems. We report a patient with persistent methicillin-resistant Staphylococcus aureus bacteremia who received various regimens for treatment of methicillin-resistant S. aureus, and demonstrate that monitoring of the time to positive blood culture might be helpful in the early recognition of treatment failure.

  5. Occurrence and characterization of inducible clindamycin resistance in canine methicillin-resistant Staphylococcus pseudintermedius.

    PubMed

    Chanchaithong, Pattrarat; Prapasarakul, Nuvee

    2016-02-01

    This study aimed to detect inducible clindamycin (iCLI) resistance in Staphylococcus pseudintermedius isolated from dogs in Thailand using D-zone testing. Strains that were iCLI-resistant were characterized by molecular typing and antibiogram and were detected in 10/200 S. pseudintermedius isolates (5%) from 7/41 dogs (17%). All were methicillin-resistant S. pseudintermedius (MRSP) and demonstrated multidrug resistance. The iCLI-resistant MRSP contained erm(B) and had identical or closely related DNA fingerprint patterns by pulsed-field gel electrophoresis. All iCLI-resistant MRSP strains belonged to the same clonal complex 112 (sequence types 111 and 112) by multilocus sequence typing. To avoid misinterpretation of clindamycin susceptibility, D-zone testing is recommended to promote rational antimicrobial selection and limit the clonal expansion of multidrug resistant bacteria.

  6. 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

  7. Metastatic Endogenous Endophthalmitis: A Rare Presentation with Methicillin-resistant Staphylococcus aureus Prostatic Abscess

    PubMed Central

    Bhavsar, Mrugank M.; Devarajan, T. V.; Nembi, P. Senthur; Ramakrishnan, Nagarajan; Mani, Ashwin K.

    2017-01-01

    A 62-year-old male with the previous history of uncontrolled diabetes and hypertension on irregular treatment presented with a history of fever, dysuria, and urinary retention with progressive painful loss of vision over a period of 2 days. His eye examination showed hypopyon, and he was diagnosed to have rapidly progressive endogenous endophthalmitis. He was started on vancomycin and piperacillin-tazobactam empirically. His blood and urine cultures grew methicillin-resistant Staphylococcus aureus (MRSA). Transesophageal echocardiography ruled out infective endocarditis. Intravitreal injection of vancomycin and ceftazidime was given. Vitreous culture also grew MRSA. A workup for possible source revealed multiple prostatic abscesses on the transrectal ultrasound. Antibiotic was changed to daptomycin in view of high vancomycin minimum inhibitory concentration. His vision was improved at the time of discharge.

  8. 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

  9. Search method for inhibitors of Staphyloxanthin production by methicillin-resistant Staphylococcus aureus.

    PubMed

    Sakai, Kent; Koyama, Nobuhiro; Fukuda, Takashi; Mori, Yukiko; Onaka, Hiroyasu; Tomoda, Hiroshi

    2012-01-01

    Staphyloxanthin, a yellow pigment produced by methicillin-resistant Staphylococcus aureus (MRSA), is a virulent factor escaping from the host immune system. A new screening method for inhibitors of staphyloxanthin production by MRSA was established using paper disks. By this screening method, inhibitors of staphyloxanthin production were selected from the natural product library (ca. 300) and from actinomycete culture broths (ca. 1000). From the natural product library, four known inhibitors of lipid metabolism, cerulenin, dihydrobisvertinol, xanthohumol and zaragozic acid, were found to inhibit staphyloxanthin production; however, typical antibiotics used clinically, including vancomycin, had no effect on staphyloxanthin production. From actinomycete culture broths, two known anthraquinones, 6-deoxy-8-O-methylrabelomycin and tetrangomycin, were found to inhibit staphyloxanthin production by MRSA in the paper disk assay. These results suggested that this screening method is useful and effective to find compounds targeting staphyloxanthin production, leading to a new type of chemotherapeutics against MRSA infection.

  10. Structural Insights into the Anti-methicillin-resistant Staphylococcus aureus (MRSA) Activity of Ceftobiprole*

    PubMed Central

    Lovering, Andrew L.; Gretes, Michael C.; Safadi, Susan S.; Danel, Franck; de Castro, Liza; Page, Malcolm G. P.; Strynadka, Natalie C. J.

    2012-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an antibiotic-resistant strain of S. aureus afflicting hospitals and communities worldwide. Of greatest concern is its development of resistance to current last-line-of-defense antibiotics; new therapeutics are urgently needed to combat this pathogen. Ceftobiprole is a recently developed, latest generation cephalosporin and has been the first to show activity against MRSA by inhibiting essential peptidoglycan transpeptidases, including the β-lactam resistance determinant PBP2a, from MRSA. Here we present the structure of the complex of ceftobiprole bound to PBP2a. This structure provides the first look at the molecular details of an effective β-lactam-resistant PBP interaction, leading to new insights into the mechanism of ceftobiprole efficacy against MRSA. PMID:22815485

  11. Bilateral blindness from orbital cellulitis caused by community-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Rutar, Tina; Zwick, Orin M; Cockerham, Kimberly P; Horton, Jonathan C

    2005-10-01

    To describe bilateral blindness resulting from infection with community-acquired methicillin-resistant Staphylococcus aureus (MRSA). Observational case report. A 44-year-old man developed proptosis, ptosis, ophthalmoplegia, and no light perception vision after attempting to lance a nasal pustule. A nasal culture grew MRSA. Imaging showed bilateral orbital cellulitis, pansinusitis, and cavernous sinus thrombosis. The right fundus showed severe ischemia, but the left fundus was essentially normal. Despite initiation of appropriate antibiotics early in the course of infection, the patient lost sight in both eyes. Surgical drainage of the paranasal sinuses and use of intravenous corticosteroids and heparin led to the resolution of orbital cellulitis. MRSA orbital cellulitis can progress to irreversible blindness despite antibiotic treatment. A new, community-acquired clone of this organism has exhibited increased potential for tissue invasion.

  12. Susceptibility of methicillin-resistant Staphylococcus aureus to minocycline and other antimicrobials.

    PubMed

    Qadri, S M; Halim, M; Ueno, Y; Saldin, H

    1994-01-01

    The incidence of methicillin-resistant Staphylococcus aureus (MRSA) is on the rise, especially in nosocomial and intravenous-drug-abuse-related infections, with a concomitant increase in morbidity, mortality and health care costs. At present the drug of choice, vancomycin, which must be administered intravenously, is expensive and can cause serious side effects in vancomycin-intolerant patients. Recently, minocycline has received much attention as an antibiotic to combat the increasing frequency of MRSA-related infections. We tested 102 recent clinical isolates of MRSA from tertiary-care patients and found none to be resistant to minocycline, with minimum inhibitory concentrations of < 1-2 micrograms/ml. The only other drug that inhibited all the strains was vancomycin, followed by ciprofloxacin (87%), clindamycin (55%) and chloramphenicol (52%). Gentamicin, beta-lactams, tetracycline and trimethoprim-sulfamethoxazole had little or no activity against our isolates of MRSA.

  13. 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.

  14. Report - Antibacterial activity of sea buckthorn (Hippophae rhamnoides L.) against methicillin resistant Staphylococcus aureus (MRSA).

    PubMed

    Qadir, Muhammad Imran; Abbas, Khizar; Younus, Adnan; Shaikh, Rehan Sadiq

    2016-09-01

    Objective of the present study was to investigate the antibacterial activity of Sea buckthorn (Hippophae rhamnoides L.) berries and leaves against methicillin resistant Staphylococcus aureus (MRSA) by using the standard disc diffusion method. Chloroform, n-hexane and aqueous extract of the plant parts were used. Doses of 2mg/ml, 4 mg/ml and 6mg/ml were tested against the microorganism, and the zone of inhibition was compared against the standard drug vancomycin. Results indicated that n-hexane and chloroform extracts of berries and n-hexane extract leaves showed significant (p<0.05) antibacterial activity comparable with vancomycin. It was concluded from the study that extracts berries and leaves of Hippophae rhamnoides have antibacterial activity against MRSA.

  15. Transmission of Methicillin-Resistant Staphylococcus aureus Infection Through Solid Organ

    PubMed Central

    Wendt, J. M.; Kaul, D.; Limbago, B. M.; Ramesh, M.; Cohle, S.; Denison, A. M.; Driebe, E. M.; Rasheed, J. K.; Zaki, S. R.; Blau, D. M.; Paddock, C. D.; McDougal, L. K.; Engelthaler, D. M.; Keim, P. S.; Roe, C. C.; Akselrod, H.; Kuehnert, M. J.; Basavaraju, S. V.

    2015-01-01

    We describe two cases of donor-derived methicillin-resistant Staphylococcus aureus (MRSA) bacteremia that developed after transplantation of organs from a common donor who died from acute MRSA endocarditis. Both recipients developed recurrent MRSA infection despite appropriate antibiotic therapy, and required prolonged hospitalization and hospital readmission. Comparison of S. aureus whole genome sequence of DNA extracted from fixed donor tissue and recipients’ isolates confirmed donor-derived transmission. Current guidelines emphasize the risk posed by donors with bacteremia from multidrug-resistant organisms. This investigation suggests that, particularly in the setting of donor endocarditis, even a standard course of prophylactic antibiotics may not be sufficient to prevent donor-derived infection. PMID:25250717

  16. Strict versus modified isolation for prevention of nosocomial transmission of methicillin-resistant Staphylococcus aureus.

    PubMed

    Ribner, B S; Landry, M N; Gholson, G L

    1986-06-01

    Patients colonized or infected with methicillin-resistant Staphylococcus aureus (MRSA) in a Surgical Intensive Care Unit and Surgical Intermediate Care Unit were placed either in Strict Isolation or cared for with modified isolation precautions. The assignment was determined by the unit in which they were hospitalized. Units were changed from one form of isolation to the other and served as their own controls. Over a 4-month study period, the rate of MRSA transmission did not change when the type of isolation precautions were altered. The ratio of colonized to infected patients also remained constant. Infected patients were usually first detected by clinical specimens, while colonized patients were usually detected by surveillance cultures performed under the study protocol. Following the study, all hospitalized patients with MRSA were placed in modified isolation precautions. Total new acquisitions of MRSA in the hospital have decreased over the subsequent 6-month period.

  17. Current methodologies on genotyping for nosocomial pathogen methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Miao, Jian; Chen, Lequn; Wang, Jingwen; Wang, Wenxin; Chen, Dingqiang; Li, Lin; Li, Bing; Deng, Yang; Xu, Zhenbo

    2017-03-08

    Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen in hospitals and the community. As the rapid spread and wide distribution of antimicrobial resistance (such as MRSA), treatment for infectious diseases caused by microorganisms has become a vital threat. Thus, early identification and genotyping are essential for further therapeutic treatment and the control of rapid expansion of MRSA. In combination with applications and data feedbacks, this review focused on the currently available molecular-based assays on their utility and performance for rapid typing of MRSA, especially on effective molecular-based methods. Besides, a common mobile element SCCmec and prevalence of HA-MRSA, LA-MRSA and CA-MRSA were introduced in this review in order to provide a more complete profile of MRSA.

  18. [Molecular characterization of resistance mechanisms: methicillin resistance Staphylococcus aureus, extended spectrum β-lactamases and carbapenemases].

    PubMed

    Oteo, Jesús; Belén Aracil, María

    2015-07-01

    Multi-drug resistance in bacterial pathogens increases morbidity and mortality in infected patients and it is a threat to public health concern by their high capacity to spread. For both reasons, the rapid detection of multi-drug resistant bacteria is critical. Standard microbiological procedures require 48-72 h to provide the antimicrobial susceptibility results, thus there is emerging interest in the development of rapid detection techniques. In recent years, the use of selective and differential culture-based methods has widely spread. However, the capacity for detecting antibiotic resistance genes and their low turnaround times has made molecular methods a reference for diagnosis of multidrug resistance. This review focusses on the molecular methods for detecting some mechanisms of antibiotic resistance with a high clinical and epidemiological impact: a) Enzymatic resistance to broad spectrum β-lactam antibiotics in Enterobacteriaceae, mainly extended spectrum β-lactamases (ESBL) and carbapenemases; and b) methicillin resistance in Staphylococcus aureus.

  19. Evaluation of the TPX MRSA assay for the detection of methicillin-resistant Staphylococcus aureus.

    PubMed

    Stenholm, T; Hakanen, A J; Salmenlinna, S; Pihlasalo, S; Härmä, H; Hänninen, P E; Huovinen, P; Vuopio, J; Kotilainen, P

    2011-10-01

    The aim of this study was to evaluate a new type of assay for the phenotypic detection of methicillin-resistant Staphylococcus aureus (MRSA). The assay is based on a point-of-care compatible two-photon excitation fluorescence detection technology (TPX). A collection of 243 epidemic MRSA isolates was tested in addition to 138 sporadic MRSA and 101 negative control strains. The assay proved to be both sensitive (97.9%) and specific (94.1%) in the identification of MRSA, with adequate positive (98.4%) and negative (92.2%) predictive values. The time required for obtaining a positive test result was less than 14 h for 99.0% of the MRSA true-positive samples. After a test run, the selectively enriched reaction mixtures may be recovered and further studied by molecular or standard phenotypic methods. The main benefits of the TPX methodology include a simple assay procedure, low reagent consumption, and a high-throughput capacity.

  20. Community-Acquired Methicillin-Resistant Staphylococcus aureus in Institutionalized Adults with Developmental Disabilities1

    PubMed Central

    Borer, Abraham; Gilad, Jacob; Yagupsky, Pablo; Peled, Nechama; Porat, Nurith; Trefler, Ronit; Shprecher-Levy, Hannah; Riesenberg, Klaris; Shipman, Miriam

    2002-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) has recently been reported to emerge in the community setting. We describe the investigation and control of a community-acquired outbreak of MRSA skin infections in a closed community of institutionalized adults with developmental disabilities. In a 9-month period in 1997, 20 (71%) of 28 residents had 73 infectious episodes. Of the cultures, 60% and 32% obtained from residents and personnel, respectively, grew S. aureus; 96% and 27% were MRSA. All isolates were genetically related by pulsed-field gel electrophoresis and belonged to a phage type not previously described in the region. No known risk factors for MRSA acquisition were found. However, 58 antibiotic courses had been administered to 16 residents during the preceding 9 months. Infection control measures, antibiotic restriction, and appropriate therapy resulted in successful termination of this outbreak. Selective antibiotic pressure may result in the emergence, persistence, and dissemination of MRSA strains, causing prolonged disease. PMID:12194775

  1. 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

  2. Classification of Epidemic Community-Acquired Methicillin-Resistant Staphylococcus aureus by Anatomical Site of Isolation

    PubMed Central

    Roberts, Jill C.

    2014-01-01

    Methicillin-resistant Staphylococcus aureus contributes significantly to cost, morbidity, and mortality due to infectious disease. We surveyed community-associated MRSA isolates to determine which strains were present within anatomical sites of interest. The most likely sources of MRSA among anatomic sites swabbed were wounds followed by the nasal cavity. The USA 300 MRSA strain was most commonly isolated among wound infections while nasal swabs largely yielded USA 100 MRSA. The frequency of isolation of USA 100 amongst community-associated strains is clinically significant as this strain is often correlated with invasive disease, exhibits broad antibiotic resistance, and has been considered to be hospital associated. The potential of USA 100 to cause serious disease and the frequency of its isolation suggest an important reservoir for opportunistic infection. These data demonstrate that MRSA epidemic clones are widespread among the community. PMID:24895625

  3. 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

  4. Antibacterial Activity of New Oxazolidin-2-One Analogues in Methicillin-Resistant Staphylococcus aureus Strains

    PubMed Central

    Córdova-Guerrero, Jesús; Hernández-Guevara, Esteban; Ramírez-Zatarain, Sandy; Núñez-Bautista, Marco; Ochoa-Terán, Adrián; Muñiz-Salazar, Raquel; Montes-Ávila, Julio; López-Angulo, Gabriela; Paniagua-Michel, Armando; Nuño Torres, Gustavo A.

    2014-01-01

    Staphylococcus aureus is one of the most common causes of nosocomial infections. The purpose of this study was the synthesis and in vitro evaluation of antimicrobial activity of 10 new 3-oxazolidin-2-one analogues on 12 methicillin resistant S. aureus (MRSA) clinical isolates. S. aureus confirmation was achieved via catalase and coagulase test. Molecular characterization of MRSA was performed by amplification of the mecA gene. Antimicrobial susceptibility was evaluated via the Kirby-Bauer disc diffusion susceptibility test protocol, using commonly applied antibiotics and the oxazolidinone analogues. Only (R)-5-((S)-1-dibenzylaminoethyl)-1,3-oxazolidin-2-one (7a) exhibited antibacterial activity at 6.6 μg. These results, allow us to infer that molecules such as 7a can be potentially used to treat infections caused by MRSA strains. PMID:24675696

  5. Antibacterial alkaloids from chelidonium majus linn (papaveraceae) against clinical isolates of methicillin-resistant Staphylococcus aureus.

    PubMed

    Zuo, Guo Ying; Meng, Fan Yan; Hao, Xiao Yan; Zhang, Yun Ling; Wang, Gen Chun; Xu, Gui Li

    2008-01-01

    This study describes the antibacterial effect of extracts and compounds isolated from the aerial part of Chelidonium majus Linn. (Papaveraceae) acting against clinical strains of methicillin-resistant Staphylococcus aureus (MRSA). The activities were evaluated by using the macrobroth dilution method and reported as the MICs/MBCs. Bioassay-guided fractionation of the most active extract from the aerial parts (EtOAc) led to the isolation of benzo[c]phenanthridine-type alkaloids 8-hydroxydihydrosanguinarine (hhS), 8-hydroxydihydrochelerythrine (hhC), which were potently active against MRSA strains. The selective antibacterial activity reported in this paper for 8-hydroxylated benzo[c]phenanthridine-type alkaloids isolated from C.majus opens the possibility that they could be helpful for the developing of new antibacterial agents for treating the infection of MRSA which has created nosocomial problem worldwide.

  6. Systemic loxoscelism in the age of community-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Rogers, Karen M; Klotz, Carrie R; Jack, Meg; Seger, Donna

    2011-02-01

    The increase in cases of community-acquired methicillin-resistant Staphylococcus aureus (MRSA), as well as its isolation from the majority of skin and soft tissue abscesses in the emergency department, requires the emergency physician to consider this diagnosis in all skin or soft tissue infections. However, making the diagnosis of MRSA when the wound is actually a cutaneous lesion of a brown recluse spider bite may have untoward consequences. Furthermore, the clinical manifestations of systemic loxoscelism may be misdiagnosed as a systemic staphylococcal infection. We present a patient with systemic loxoscelism who was diagnosed with a systemic infection and received an unnecessary surgical procedure. Copyright © 2010 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.

  7. The spa typing of methicillin-resistant Staphylococcus aureus isolates by High Resolution Melting (HRM) analysis.

    PubMed

    Fasihi, Yasser; Fooladi, Saba; Mohammadi, Mohammad Ali; Emaneini, Mohammad; Kalantar-Neyestanaki, Davood

    2017-09-06

    Molecular typing is an important tool for control and prevention of infection. A suitable molecular typing method for epidemiological investigation must be easy to perform, highly reproducible, inexpensive, rapid and easy to interpret. In this study, two molecular typing methods including the conventional PCR-sequencing method and high resolution melting (HRM) analysis were used for staphylococcal protein A (spa) typing of 30 Methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered from clinical samples. Based on PCR-sequencing method results, 16 different spa types were identified among the 30 MRSA isolates. Among the 16 different spa types, 14 spa types separated by HRM method. Two spa types including t4718 and t2894 were not separated from each other. According to our results, spa typing based on HRM analysis method is very rapid, easy to perform and cost-effective, but this method must be standardized for different regions, spa types, and real-time machinery.

  8. Antimicrobial Drug Use and Methicillin-resistant Staphylococcus aureus, Aberdeen, 1996–2000

    PubMed Central

    Monnet, Dominique L.; López-Lozano, José María; Beyaert, Arielle; Camacho, Máximo; Wilson, Rachel; Stuart, David; Gould, Ian M.

    2004-01-01

    Similar to many hospitals worldwide, Aberdeen Royal Infirmary has had an outbreak of methicillin-resistant Staphylococcus aureus (MRSA). In this setting, the outbreak is attributable to two major clones. The relationships between antimicrobial use and MRSA prevalence were analyzed by time-series analysis. From June 1997 to December 2000, dynamic, temporal relationships were found between monthly %MRSA and previous %MRSA, macrolide use, third-generation cephalosporin use, and fluoroquinolone use. This study suggests that use of antimicrobial drugs to which the MRSA outbreak strains are resistant may be an important factor in perpetuating the outbreak. Moreover, this study confirmed the ecologic effect of antimicrobial drug use (i.e., current antimicrobial use) may have an effect on resistance in future patients. Although these results may not be generalized to other hospitals, they suggest new directions for control of MRSA, which has thus far proved difficult and expensive. PMID:15496245

  9. Identification and characterisation of a Streptomyces sp. isolate exhibiting activity against methicillin-resistant Staphylococcus aureus.

    PubMed

    Higginbotham, Sarah J; Murphy, Cormac D

    2010-01-01

    A soil-borne bacterium exhibiting broad antimicrobial activity, including activity against MRSA, was investigated. The bacterium was identified using morphological, biochemical and genetic techniques. The 16S rDNA sequence of the isolate indicated that it was most closely related to Streptomyces lavendulae and Streptomyces globosus. DNA-DNA hybridisation revealed 80% homology with S. globosus DSM41122. The antibiotic was partially purified from the culture supernatant using a combination of precipitation, charcoal and ion exchange. The antibiotic was found to be water-soluble and highly thermally stable at acidic pH. It inhibited the growth of S. lavendulae but not Streptomyces tenebrarius. Significantly, the partially purified antibiotic displayed activity towards clinical isolates of methicillin-resistant Staphylococcus aureus, representative of the major clonal complexes.

  10. 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.

  11. Purification, crystallization and data collection of methicillin-resistant Staphylococcus aureus Sar2676, a pantothenate synthetase

    PubMed Central

    Seetharamappa, Jaldappagari; Oke, Muse; Liu, Huanting; McMahon, Stephen A.; Johnson, Kenneth A.; Carter, Lester; Dorward, Mark; Zawadzki, Michal; Overton, Ian M.; van Niekirk, C. A. Johannes; Graham, Shirley; Botting, Catherine H.; Taylor, Garry L.; White, Malcolm F.; Barton, Geoffrey J.; Coote, Peter J.; Naismith, James H.

    2007-01-01

    Sar2676, a pantothenate synthetase with a molecular weight of 31 419 Da from methicillin-resistant Staphylococcus aureus, has been expressed, purified and crystallized at 293 K. The protein crystallizes in a primitive triclinic lattice, with unit-cell parameters a = 45.3, b = 60.5, c = 117.6 Å, α = 87.2, β = 81.2, γ = 68.4°. A complete data set has been collected to 2.3 Å resolution at the ESRF. Consideration of the likely solvent content suggested the asymmetric unit to contain four molecules. This has been confirmed by molecular-replacement phasing calculations, which give a solution with four monomers using a monomer of pantothenate synthetase from Escherichia coli (PDB code 1iho), which is 41% identical to Sar2676, as a search model. PMID:17554169

  12. Prevalence and characterization of methicillin-resistant Staphylococcus aureus in raw meat in Korea.

    PubMed

    Lim, Suk-Kyung; Nam, Hyang-Mi; Park, Hyun-Jung; Lee, Hee-Soo; Choi, Min-Jung; Jung, Suk-Chan; Lee, Ji-Yeon; Kim, Young-Cho; Song, Si-Wook; Wee, Sung-Hwan

    2010-04-01

    A total of 2,858 meat samples collected during 2003-2008 in Korea were investigated, and methicillin-resistant Staphylococcus aureus (MRSA) were isolated from 1.0% (9/890) of beef, 0.3% (4/1,055) of pork, and 0.3% (3/913) of chicken meat samples, respectively. MRSA isolates showed the two sequence types (STs), ST72 from beef and pork and ST692 from chicken meat. MRSA isolates from beef and pork were Panton-Valentine leukocidin -negative, staphylococcal cassette chromosome mec type IVa strain with ST 72, which is the most prevalent type of community acquired-MRSA in Korea. An identical pulse-field gel electrophoresis pattern was detected among 10 of 16 MRSA isolates: 9 strains from beef (n=5) and pork (n=4) in 2008, respectively, and one strain from beef in 2005.

  13. Evaluation of Clinical Laboratory Standards Institute interpretive criteria for methicillin-resistant Staphylococcus pseudintermedius isolated from dogs.

    PubMed

    Schissler, Jennifer R; Hillier, Andrew; Daniels, Joshua B; Cole, Lynette K; Gebreyes, Wondwossen A

    2009-09-01

    The Clinical and Laboratory Standards Institute published in 2008 new interpretive criteria for the identification of methicillin resistance in staphylococci isolated from animals. The sensitivity of the 2008 interpretive criteria for mecA gene-positive Staphylococcus pseudintermedius, compared with the previous criteria of 2004, was investigated. Thirty clinical isolates of methicillin-resistant S. pseudintermedius from dogs were used. The presence of the mecA gene was determined by polymerase chain reaction. The minimum inhibitory concentration for oxacillin was determined by broth microdilution. The 2008 breakpoint of >or=4 microg/ml for methicillin resistance resulted in a diagnostic sensitivity of 73.3% (22/30). The 2004 breakpoint guideline of >or=0.5 microg/ml resulted in a diagnostic sensitivity of 97% (29/30). For oxacillin disk diffusion, the 2008 interpretive criterion of methicillin resistance resulted in a sensitivity of 70% (21/30). If intermediate isolates (11 or 12 mm) were considered resistant, the sensitivity was 93% (28/30). If intermediate isolates (11 or 12 mm) were considered resistant, the sensitivity was 93% (28/30). Application of the 2004 interpretive criterion of methicillin resistance (as used for Staphylococcus aureus) resulted in a diagnostic sensitivity of 6.7% (2/30). The interpretive criterion of methicillin resistance of canine S. pseudintermedius.

  14. [Evaluation of vancomycin, teicoplanin, linezolide and tigecycline susceptibilities of nosocomial methicillin-resistant Staphylococcus strains by E-test].

    PubMed

    Pelitli, Tamer Sami; Cesur, Salih; Kınıklı, Sami; Irmak, Hasan; Demiröz, Ali Pekcan; Karakoç, Esra

    2011-10-01

    The aim of this study was to determine the minimal inhibitory concentration (MIC) values of vancomycin, teicoplanin, tigecycline and linezolid in 100 methicillin-resistant staphylococci [21 methicillin-resistant Staphylococcus aureus (MRSA) and 79 methicillin-resistant coagulase negative staphylococcus (MR-CNS)] isolated as agents of nosocomial infection from patients at Ankara Training and Research Hospital between June 2005-March 2007. The MIC values for vancomycin, teicoplanin, linezolid and tigecycline were tested by E-test method (AB Biodisk, Sweden). For 21 MRSA strains MIC50 and MIC90 values were as follows: vancomycin 0.125 µg/ml and 1 µg/ml; teicoplanin 0.5 µg/ml and 3 µg/ml, linezolid 0.047 µg/ml and 0.19 µg/ml; tigecycline 0.094 µg/ml and 0.5 µg/ml, respectively. For 79 MR-CNS strains MIC50 and MIC90 values were as follows: vancomycin 0.5 µg/ml and 2 µg/ml; teicoplanin 2 µg/ml and 4 µg/ml; linezolid 0.125 µg/ml and 0.25 µg/ml; tigecycline 0.38 µg/ml and 0.5 µg/ml, respectively. No resistance to vancomycin, teicoplanin, tigecycline and linezolid were determined in methicillin-resistant staphylococcus strains isolated from the inpatients in our hospital. Among glycopeptides, MIC50 and MIC90 values of vancomycin were found to be lower than that of teicoplanin.

  15. Carriage of methicillin-resistant Staphylococcus pseudintermedius in small animal veterinarians: indirect evidence of zoonotic transmission.

    PubMed

    Paul, N C; Moodley, A; Ghibaudo, G; Guardabassi, L

    2011-12-01

    Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is increasingly reported in small animals and cases of human infections have already been described despite its recent emergence in veterinary practice. We investigated the prevalence of MRSP and methicillin-resistant Staphylococcus aureus (MRSA) among small animal dermatologists attending a national veterinary conference in Italy. Nasal swabs were obtained from 128 veterinarians, seven of which harboured MRSP (n = 5; 3.9%) or MRSA (n = 2; 1.6%). A follow-up study of two carriers revealed that MRSP persisted for at least 1 month in the nasal cavity. Methicillin-susceptible S. aureus (MSSA) was isolated from 32 (25%) conference participants, whereas methicillin-susceptible S. pseudintermedius (MSSP) was not detected, suggesting that MRSP may have a particular ability to colonize humans compared to MSSP. All isolates were characterized by spa typing. Methicillin-resistant isolates were further typed by antimicrobial susceptibility testing, SCCmec and multi-locus sequence typing. Two lineages previously associated with pets were identified among the five MRSP isolates; the European epidemic clone ST71-SCCmec II-III and ST106-SCCmec IV. One of the two MRSA isolates displayed a genotype (ST22- SCCmecIV) frequently reported in dogs and cats. MRSP isolates were resistant to more antimicrobial agents compared with MRSA isolates and displayed the typical multidrug resistance patterns of MRSP in pets. The 32 MSSA isolates belonged to 20 spa types and the most frequent types (t12, t15 and t166) were associated with common S. aureus lineages in humans (CC30 and CC45). Although low, the 3.9% MRSP carriage rate found among small animal dermatologists was surprising in consideration of the rare occurrence of S. pseudintermedius in humans, the lack of MSSP detection and the recent appearance of MRSP in Europe. As cases of human MRSP infection have been linked with pets, veterinarians should be aware of this zoonotic risk

  16. 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

  17. Antimicrobial susceptibility of methicillin-resistant Staphylococcus pseudintermedius isolated from veterinary clinical cases in the UK.

    PubMed

    Maluping, R P; Paul, N C; Moodley, A

    2014-01-01

    Staphylococcus pseudintermedius is a leading aetiologic agent of pyoderma and other body tissue infections in dogs and cats. In recent years, an increased prevalence of methicillin-resistant S. pseudintermedius (MRSP) has been reported. Isolation of MRSP in serious infections poses a major therapeutic challenge as strains are often resistant to all forms of systemic antibiotic used to treat S. pseudintermedius -related infections. This study investigates the occurrence of MRSP from a total of 7183 clinical samples submitted to the authors' laboratories over a 15-month period. Identification was based on standard microbiological identification methods, and by S. pseudintermedius-specific nuc polymerase chain reaction (PCR). Methicillin resistance was confirmed by PBP2a latex agglutination and mecA PCR. Susceptibility against non-beta-lactam antibiotics was carried out using a disc-diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. In addition, susceptibility to pradofloxacin--a new veterinary fluoroquinolone--was also investigated. SCCmec types were determined by multiplex PCR. Staphylococcus pseudintermedius was isolated from 391 (5%) samples and 20 were confirmed as MRSP from cases of pyoderma, otitis, wound infections, urinary tract infection and mastitis in dogs only. All 20 isolates were resistant to clindamycin and sulphamethoxazole/trimethoprim. Nineteen were resistant to chloramphenicol, enrofloxacin, gentamicin, marbofloxacin and pradofloxacin; additionally, seven isolates were resistant to tetracycline. Fifteen isolates carried SCCmec type II-III, four isolates had type V and one harboured type IV. To date, only a few scientific papers on clinical MRSP strains isolated from the UK have been published, thus the results from this study would provide additional baseline data for further investigations.

  18. Methicillin-resistant Staphylococcus aureus (MRSA) in three dairy herds in southwest Germany.

    PubMed

    Spohr, M; Rau, J; Friedrich, A; Klittich, G; Fetsch, A; Guerra, B; Hammerl, J A; Tenhagen, B-A

    2011-06-01

    The objective of this study was to analyse the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in three dairy herds in the southwest of Germany that had experienced individual cases of clinical and subclinical mastitis associated with MRSA. The herds were identified by the detection of MRSA during routine resistance testing of mastitis pathogens. All quarters of all cows in the herds that were positive on California Mastitis Test were sampled for bacteriological analysis on two occasions. Bulk tank milk samples were also tested. Furthermore, nasal swabs were collected from people working on the farms and from cattle. Environmental samples were collected from associated pig holdings. Isolates were characterized using spa-typing and testing for antimicrobial resistance. Our results revealed a substantial spread of MRSA in the three dairy herds. In the first of the two investigations carried out on all cows in the three herds, milk samples of 5.1-16.7% of dairy cows were found positive for MRSA. The respective proportions in the second herd level investigation were 1.4-10.0%. Quarters harbouring MRSA had higher somatic cell counts than quarters that were negative on culture. Methicillin-resistant Staphylococcus aureus were also detected in nasal swabs of staff (7/9), cows (7/15) and calves (4/7), bulk tank milk samples (3/3) and environmental samples from pig premises (4/5) on the farm. Herds B and C had no contact to herd A. However, in all three herds MRSA of spa-type t011 were detected in milk samples. Results show that MRSA of spa-type t011 is a problem in dairy farms that needs urgent attention. © 2010 Blackwell Verlag GmbH.

  19. Identification of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from burn patients by multiplex PCR.

    PubMed

    Montazeri, Effat Abbasi; Khosravi, Azar Dokht; Jolodar, Abbas; Ghaderpanah, Mozhgan; Azarpira, Samireh

    2015-05-01

    Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS) as important human pathogens are causes of nosocomial infections worldwide. Burn patients are at a higher risk of local and systemic infections with these microorganisms. A screening method for MRSA by using a multiplex polymerase chain reaction (PCR) targeting the 16S ribosomal RNA (rRNA), mecA, and nuc genes was developed. The aim of the present study was to investigate the potential of this PCR assay for the detection of MRSA strains in samples from burn patients. During an 11-month period, 230 isolates (53.11%) of Staphylococcus spp. were collected from burn patients. The isolates were identified as S. aureus by using standard culture and biochemical tests. DNA was extracted from bacterial colonies and multiplex PCR was used to detect MRSA and MRCoNS strains. Of the staphylococci isolates, 149 (64.9%) were identified as S. aureus and 81 (35.21%) were described as CoNS. Among the latter, 51 (62.97%) were reported to be MRCoNS. From the total S. aureus isolates, 132 (88.6%) were detected as MRSA and 17 (11.4%) were methicillin-susceptible S. aureus (MSSA). The presence of the mecA gene in all isolates was confirmed by using multiplex PCR as a gold standard method. This study presented a high MRSA rate in the region under investigation. The 16S rRNA-mecA-nuc multiplex PCR is a good tool for the rapid characterization of MRSA strains. This paper emphasizes the need for preventive measures and choosing effective antimicrobials against MRSA and MRCoNS infections in the burn units. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  20. Certified Athletic Trainers' Knowledge of Methicillin-Resistant Staphylococcus aureus and Common Disinfectants

    PubMed Central

    Kahanov, Leamor; Gilmore, Elizabeth J.; Eberman, Lindsey E.; Roberts, Jeffrey; Semerjian, Tamar; Baldwin, Linda

    2011-01-01

    Context: Methicillin-resistant Staphylococcus aureus (MRSA) infections are increasingly common in athletic settings. The MRSA knowledge and infection-control practices of certified athletic trainers (ATs) and the cleanliness of the athletic training room are important factors in preventing MRSA infections. Objective: To assess knowledge of MRSA and the use of common disinfectants among ATs and to explore their infection-control practices. Design: Cross-sectional study. Setting: High school and collegiate athletic training rooms. Patients or Other Participants: A total of 163 ATs from National Collegiate Athletic Association Divisions I, II, and III and high schools, representing all 10 National Athletic Trainers' Association districts. Main Outcome Measure(s): Frequencies, analyses of variance, and χ2 tests were used to assess current practices and opinions and relationships between factors. Results: Methicillin-resistant Staphylococcus aureus was perceived as a national problem by 92% of respondents; 57% perceived MRSA as a problem in their practice setting. Most respondents had treated general infections (88%), staphylococcal infections (75%), and MRSA infections (57%). Male sex was associated with treating all 3 types of infections (χ2 test, P < .05). Noncurriculum education was associated with a lack of recognition of environmental issues as risk factors and with the use of isopropyl alcohol for disinfection (χ2 test, P < .05). For example, 10% of respondents did not recognize that contaminated whirlpools can be a source of MRSA infection. Respondents also incorrectly identified effective cleaning solutions. Thirty percent of respondents cleaned their hands frequently or sometimes before treating each athlete and 35% cleaned their hands sometimes, occasionally, or never after seeing each athlete. Conclusions: The majority of ATs were informed about MRSA and made correct disinfection choices. However, improvements are still needed, and not all ATs were using

  1. 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

  2. The Effectiveness of Bacteriophages against Methicillin-Resistant Staphylococcus aureus ST398 Nasal Colonization in Pigs

    PubMed Central

    Duim, Birgitta; Fluit, Ad C; Carney, Jennifer; van Nes, Arie; Wagenaar, Jaap A

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important colonizer in animals and an opportunistic pathogen in humans. In humans, MRSA can cause infections that might be difficult to treat because of antimicrobial resistance. The use of bacteriophages has been suggested as a potential approach for the control of MRSA colonization to minimize the—often occupational—exposure of humans. The aim of this study was to assess the efficacy of bacteriophage treatment on porcine nasal colonization with MRSA in vitro, in vivo, and ex vivo. The effectiveness of a bacteriophage combination of phage K*710 and P68 was assessed in vitro by incubating them with MRSA V0608892/1 (ST398) measuring the OD600 hourly. To study the in vivo effect, bacteriophages were administered in a gel developed for human application, which contain 109 plaque-forming units (pfu)/mL (K and P68 in a 19.25:1 ratio) for 5 days to piglets (N = 8) that were experimentally colonized with the MRSA strain. Eight piglets experimentally colonized were used as a negative control. The MRSA strain was also used to colonize porcine nasal mucosa explants and bacteriophages were applied to assess the ex vivo efficacy of treatment. Bacteriophages were effective in vitro. In vivo, sixteen piglets were colonized with MRSA but the number of CFU recovered after the application of the bacteriophages in 8 piglets was not reduced compared to the control animals (approx. 105 CFU/swab). In the ex vivo model, 108 CFU were used to establish colonization with MRSA; a reduction of colonization was not observed after application of bacteriophages. However, application of mupirocin both in vivo and ex vivo resulted in a near eradication of MRSA. In conclusion: i) The MRSA strain was killed in the presence of the bacteriophages phage K*710 and P68 in vitro. ii) Bacteriophages did not reduce porcine nasal colonization in vivo or ex vivo. Physiological in vivo and ex vivo conditions may explain these observations. Efficacy

  3. The Effectiveness of Bacteriophages against Methicillin-Resistant Staphylococcus aureus ST398 Nasal Colonization in Pigs.

    PubMed

    Verstappen, Koen M; Tulinski, Pawel; Duim, Birgitta; Fluit, Ad C; Carney, Jennifer; van Nes, Arie; Wagenaar, Jaap A

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important colonizer in animals and an opportunistic pathogen in humans. In humans, MRSA can cause infections that might be difficult to treat because of antimicrobial resistance. The use of bacteriophages has been suggested as a potential approach for the control of MRSA colonization to minimize the-often occupational-exposure of humans. The aim of this study was to assess the efficacy of bacteriophage treatment on porcine nasal colonization with MRSA in vitro, in vivo, and ex vivo. The effectiveness of a bacteriophage combination of phage K*710 and P68 was assessed in vitro by incubating them with MRSA V0608892/1 (ST398) measuring the OD600 hourly. To study the in vivo effect, bacteriophages were administered in a gel developed for human application, which contain 109 plaque-forming units (pfu)/mL (K and P68 in a 19.25:1 ratio) for 5 days to piglets (N = 8) that were experimentally colonized with the MRSA strain. Eight piglets experimentally colonized were used as a negative control. The MRSA strain was also used to colonize porcine nasal mucosa explants and bacteriophages were applied to assess the ex vivo efficacy of treatment. Bacteriophages were effective in vitro. In vivo, sixteen piglets were colonized with MRSA but the number of CFU recovered after the application of the bacteriophages in 8 piglets was not reduced compared to the control animals (approx. 105 CFU/swab). In the ex vivo model, 108 CFU were used to establish colonization with MRSA; a reduction of colonization was not observed after application of bacteriophages. However, application of mupirocin both in vivo and ex vivo resulted in a near eradication of MRSA. i) The MRSA strain was killed in the presence of the bacteriophages phage K*710 and P68 in vitro. ii) Bacteriophages did not reduce porcine nasal colonization in vivo or ex vivo. Physiological in vivo and ex vivo conditions may explain these observations. Efficacy in the ex vivo

  4. Blue Light Eliminates Community-Acquired Methicillin-Resistant Staphylococcus aureus in Infected Mouse Skin Abrasions

    PubMed Central

    Dai, Tianhong; Gupta, Asheesh; Huang, Ying-Ying; Sherwood, Margaret E.; Murray, Clinton K.; Vrahas, Mark S.; Kielian, Tammy

    2013-01-01

    Abstract Background and objective: Bacterial skin and soft tissue infections (SSTI) affect millions of individuals annually in the United States. Treatment of SSTI has been significantly complicated by the increasing emergence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) strains. The objective of this study was to demonstrate the efficacy of blue light (415±10 nm) therapy for eliminating CA-MRSA infections in skin abrasions of mice. Methods: The susceptibilities of a CA-MRSA strain (USA300LAC) and human keratinocytes (HaCaT) to blue light inactivation were compared by in vitro culture studies. A mouse model of skin abrasion infection was developed using bioluminescent USA300LAC::lux. Blue light was delivered to the infected mouse skin abrasions at 30 min (acute) and 24 h (established) after the bacterial inoculation. Bioluminescence imaging was used to monitor in real time the extent of infection in mice. Results: USA300LAC was much more susceptible to blue light inactivation than HaCaT cells (p=0.038). Approximately 4.75-log10 bacterial inactivation was achieved after 170 J/cm2 blue light had been delivered, but only 0.29 log10 loss of viability in HaCaT cells was observed. Transmission electron microscopy imaging of USA300LAC cells exposed to blue light exhibited disruption of the cytoplasmic content, disruption of cell walls, and cell debris. In vivo studies showed that blue light rapidly reduced the bacterial burden in both acute and established CA-MRSA infections. More than 2-log10 reduction of bacterial luminescence in the mouse skin abrasions was achieved when 41.4 (day 0) and 108 J/cm2 (day 1) blue light had been delivered. Bacterial regrowth was observed in the mouse wounds at 24 h after the blue light therapy. Conclusions: There exists a therapeutic window of blue light for bacterial infections where bacteria are selectively inactivated by blue light while host tissue cells are preserved. Blue light therapy has

  5. Blue light eliminates community-acquired methicillin-resistant Staphylococcus aureus in infected mouse skin abrasions.

    PubMed

    Dai, Tianhong; Gupta, Asheesh; Huang, Ying-Ying; Sherwood, Margaret E; Murray, Clinton K; Vrahas, Mark S; Kielian, Tammy; Hamblin, Michael R

    2013-11-01

    Bacterial skin and soft tissue infections (SSTI) affect millions of individuals annually in the United States. Treatment of SSTI has been significantly complicated by the increasing emergence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) strains. The objective of this study was to demonstrate the efficacy of blue light (415 ± 10 nm) therapy for eliminating CA-MRSA infections in skin abrasions of mice. The susceptibilities of a CA-MRSA strain (USA300LAC) and human keratinocytes (HaCaT) to blue light inactivation were compared by in vitro culture studies. A mouse model of skin abrasion infection was developed using bioluminescent USA300LAC::lux. Blue light was delivered to the infected mouse skin abrasions at 30 min (acute) and 24 h (established) after the bacterial inoculation. Bioluminescence imaging was used to monitor in real time the extent of infection in mice. USA300LAC was much more susceptible to blue light inactivation than HaCaT cells (p=0.038). Approximately 4.75-log10 bacterial inactivation was achieved after 170 J/cm(2) blue light had been delivered, but only 0.29 log10 loss of viability in HaCaT cells was observed. Transmission electron microscopy imaging of USA300LAC cells exposed to blue light exhibited disruption of the cytoplasmic content, disruption of cell walls, and cell debris. In vivo studies showed that blue light rapidly reduced the bacterial burden in both acute and established CA-MRSA infections. More than 2-log10 reduction of bacterial luminescence in the mouse skin abrasions was achieved when 41.4 (day 0) and 108 J/cm(2) (day 1) blue light had been delivered. Bacterial regrowth was observed in the mouse wounds at 24 h after the blue light therapy. There exists a therapeutic window of blue light for bacterial infections where bacteria are selectively inactivated by blue light while host tissue cells are preserved. Blue light therapy has the potential to rapidly reduce the bacterial load in SSTI.

  6. Methicillin-Resistant Staphylococcus aureus Colonization and Risk of Subsequent Infection in Critically Ill Children: Importance of Preventing Nosocomial Methicillin-Resistant Staphylococcus aureus Transmission

    PubMed Central

    Goldner, Brian W.; Ross, Tracy; Shepard, John W.; Carroll, Karen C.

    2011-01-01

    Background. Methicillin-resistant Staphylococcus aureus (MRSA) colonization is a predictor of subsequent infection in hospitalized adults. The risk of subsequent MRSA infections in hospitalized children colonized with MRSA is unknown. Methods. Children admitted to an academic medical center’s pediatric intensive care unit between March 2007 and March 2010 were included in the study. Anterior naris swabs were cultured to identify children with MRSA colonization at admission. Laboratory databases were queried and National Healthcare Safety Network definitions applied to identify patients with MRSA infections during their hospitalization or after discharge. Results. The MRSA admission prevalence among 3140 children was 4.9%. Overall, 56 children (1.8%) developed an MRSA infection, including 13 (8.5%) colonized on admission and 43 (1.4%) not colonized on admission (relative risk [RR], 5.9; 95% confidence interval [CI], 3.4–10.1). Of those, 10 children (0.3%) developed an MRSA infection during their hospitalization, including 3 of 153 children (1.9%) colonized on admission and 7 of 2987 children (0.2%) not colonized on admission (RR, 8.4; 95% CI, 2.7–25.8). African-Americans and those with public health insurance were more likely to get a subsequent infection (P < .01 and P = .03, respectively). We found that 15 children acquired MRSA colonization in the pediatric intensive care unit, and 7 (47%) developed a subsequent MRSA infection. Conclusions. MRSA colonization is a risk factor for subsequent MRSA infection in children. Although MRSA colonized children may have lower risks of subsequent infection than adults, children who acquire MRSA in the hospital have similarly high rates of infection. Preventing transmission of MRSA in hospitalized children should remain a priority. PMID:21878424

  7. Occurrence and characteristics of methicillin-resistant and -susceptible Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci from Japanese retail ready-to-eat raw fish.

    PubMed

    Hammad, Ahmed M; Watanabe, Wataru; Fujii, Tomoko; Shimamoto, Tadashi

    2012-06-01

    Staphylococci are not part of the normal fish microflora. The presence of staphylococci on fish is an indication of (a) post-harvest contamination due to poor personnel hygiene, or (b) disease in fish. The aim of this study was to determine the prevalence, molecular genetic characteristics, antibiotic resistance and virulence factors of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) isolated from 200 samples of retail ready-to-eat raw fish (sashimi) collected from the Japanese prefecture of Hiroshima. We characterized 180 staphylococcal strains. A majority of the grocery stores surveyed (92%, 23/25) contained fish contaminated with Staphylococcus species. We recovered 175 S. aureus isolates from 174 (87%, 174/200) samples, with 170 isolates of MSSA. For the MRSA and MR-CoNS, 10 isolates were obtained from 10 samples (5%, 10/200) collected from 10 shops (40%, 10/25) belonging to four supermarket chains. SCCmec typing revealed the presence of a type IV.1 SCCmec cassette in S. warneri isolates, a type II.1 SCCmec cassette in S. haemolyticus isolates and a cassette in methicillin-resistant S. aureus (MRSA) isolates that could not be typed. Molecular typing of two MRSA isolates by spa sequencing and multilocus sequence typing (MLST) identified t1767 and ST8, respectively. Antibiotic resistance genes that confer resistance to aminoglycosides, tetracyclines, β-lactams, macrolides, lincosamides and streptogramin B (MLS(B)) antibiotics were detected. Genes encoding one or more of the following virulence factors: staphylococcal enterotoxins (seb, and sed), toxic shock syndrome toxin 1 (tst), exfoliative toxin (etaA) were detected in 14.2% (25/175) of S. aureus isolates. The accessory gene regulator (agr) typing of S. aureus isolates revealed that agr type 1 was most prevalent (96.5%, 169/175) followed by type 2 (2.2%, 4/175) and type 3 (1.1%, 2/175). None of

  8. Antibiotic additive and synergistic action of rutin, morin and quercetin against methicillin resistant Staphylococcus aureus.

    PubMed

    Amin, Muhammad Usman; Khurram, Muhammad; Khattak, Baharullah; Khan, Jafar

    2015-03-12

    To determine the effect of flavonoids in conjunction with antibiotics in methicillin resistant Staphylococcus aureus (MRSA) a study was designed. The flavonoids included Rutin, Morin, Qurecetin while antibiotics included ampicillin, amoxicillin, cefixime, ceftriaxone, vancomycin, methicillin, cephradine, erythromycin, imipenem, sulphamethoxazole/trimethoprim, ciprofloxacin and levolfloxacin. Test antibiotics were mostly found resistant with only Imipenem and Erythromycin found to be sensitive against 100 MRSA clinical isolates and S. aureus (ATCC 43300). The flavonoids were tested alone and also in different combinations with selected antibiotics. Antibiotics and flavonoids sensitivity assays were carried using disk diffusion method. The combinations found to be effective were sifted through MIC assays by broth macro dilution method. Exact MICs were determined using an incremental increase approach. Fractional inhibitory concentration indices (FICI) were determined to evaluate relationship between antibiotics and flavonoids is synergistic or additive. Potassium release was measured to determine the effect of antibiotic-flavonoids combinations on the cytoplasmic membrane of test bacteria. Antibiotic and flavonoids screening assays indicated activity of flavanoids against test bacteria. The inhibitory zones increased when test flavonoids were combined with antibiotics facing resistance. MICs of test antibiotics and flavonoids reduced when they were combined. Quercetin was the most effective flavonoid (MIC 260 μg/ml) while morin + rutin + quercetin combination proved most efficient with MIC of 280 + 280 + 140 μg/ml. Quercetin + morin + rutin with amoxicillin, ampicillin, cephradine, ceftriaxone, imipenem, and methicillin showed synergism, while additive relationship was indicated between morin + rutin and amoxicillin, cephradine, ceftriaxone, imipenem, and methicillin. Quercetin alone had an additive effect with ampicillin, cephradine

  9. Methicillin-resistant Staphylococcus aureus (MRSA) catheter-related bacteraemia in haemodialysis patients.

    PubMed

    Cuervo, Guillermo; Camoez, Mariana; Shaw, Evelyn; Dominguez, María Ángeles; Gasch, Oriol; Padilla, Belén; Pintado, Vicente; Almirante, Benito; Molina, José; López-Medrano, Francisco; Ruiz de Gopegui, Enrique; Martinez, José A; Bereciartua, Elena; Rodriguez-Lopez, Fernando; Fernandez-Mazarrasa, Carlos; Goenaga, Miguel Ángel; Benito, Natividad; Rodriguez-Baño, Jesús; Espejo, Elena; Pujol, Miquel

    2015-10-30

    The aim of the study was to determine clinical and microbiological differences between patients with methicillin-resistant Staphylococcus aureus (MRSA) catheter-related bacteraemia (CRB) undergoing or not undergoing haemodialysis, and to compare outcomes. Prospective multicentre study conducted at 21 Spanish hospitals of patients with MRSA bacteraemia diagnosed between June 2008 and December 2009. Patients with MRSA-CRB were selected. Data of patients on haemodialysis (HD-CRB) and those not on haemodialysis (non-HD-CRB) were compared. Among 579 episodes of MRSA bacteraemia, 218 (37.7%) were CRB. Thirty-four (15.6%) were HD-CRB and 184 (84.4%) non-HD-CRB. All HD-CRB patients acquired the infection at dialysis centres, while in 85.3% of the non-HD-CRB group the infection was nosocomial (p < .001). There were no differences in age, gender or severity of bacteraemia (Pitt score); comorbidities (Charlson score ≥ 4) were higher in the HD-CRB group than in the non-HD-CRB group (73.5% vs. 46.2%, p = .003). Although there were no differences in VAN-MIC ≥ 1.5 mg/L according to microdilution, using the E-test a higher rate of VAN-MIC ≥ 1.5 mg/L was observed in HD-CRB than in non-HD-CRB patients (63.3% vs. 44.1%, p = .051). Vancomycin was more frequently administered in the HD-CRB group than in the non-HD-CRB group (82.3% vs. 42.4%, p = <.001) and therefore the appropriate empirical therapy was significantly higher in HD-CRB group (91.2% vs. 73.9%, p = .029). There were no differences with regard to catheter removal (79.4% vs. 84.2%, p = .555, respectively). No significant differences in mortality rate were observed between both groups (Overall mortality: 11.8% vs. 27.2%, p = .081, respectively), but there was a trend towards a higher recurrence rate in HD-CRB group (8.8% vs. 2.2%, p = .076). In our multicentre study, ambulatory patients in chronic haemodialysis represented a significant proportion of cases of MRSA catheter-related bacteraemia. Although

  10. Methicillin-resistant Staphylococcus aureus (MRSA) in slaughtered pigs and abattoir workers in Italy.

    PubMed

    Normanno, Giovanni; Dambrosio, Angela; Lorusso, Vanessa; Samoilis, Georgios; Di Taranto, Pietro; Parisi, Antonio

    2015-10-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen present in the hospital environment (HA-MRSA), in the community (CA-MRSA) and in livestock, including pigs (LA-MRSA). MRSA may enter the human food chain during slaughtering and may infect humans coming into direct contact with pigs or pork products. This study aimed to determine the prevalence and characteristics of MRSA isolated from pigs and workers at industrial abattoirs in southern Italy. A total of 215 pig nasal swabs were screened for the presence of MRSA using PCR. An MRSA isolate was detected from each mecA/nuc PCR-positive sample and characterized by spa-typing, Multi-Locus Sequence Typing, SCC-mec and Panton-Valentine Leukocidin (PVL), and also tested for the production of staphylococcal enterotoxins (SEs). Eighty-one MRSA isolates (37.6%) were obtained from the 215 pig nasal swabs; 37 of these isolates were further characterized, and showed 18 different spa-types and 8 different STs. The most frequently recovered STs were ST398 (CC398-t034, t011, t899, t1939 - 43.2%) followed by ST8 (CC8-t008, t064, t2953, t5270 - 24.3%) and ST1 (CC1-t127, t174, t2207 - 10.8%). Nine MRSA isolates were obtained from the 113 human swabs; the isolates showed 5 different spa-types and 5 different STs, including the novel ST2794 (t159). The most representative STs recovered were ST1 (CC1-t127) and ST398 (CC398-t034) (33.3%). None of the MRSA isolates showed the ability to produce SEs and PVL and all resulted resistant to two or more classes of antimicrobials. This study shows the great genetic diversity of MRSA strains in slaughtered pigs and in abattoir employees in Italy, and clearly demonstrates the need for improved hygiene standards to reduce the risk of occupational and food-borne infection linked to the handling/consumption of raw pork containing MRSA.

  11. 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

  12. 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

  13. 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.

  14. Prevalence and characterization of methicillin-resistant Staphylococcus pseudintermedius in pets from South China.

    PubMed

    Feng, Yanyan; Tian, Wei; Lin, Dachuan; Luo, Qianyi; Zhou, Yingze; Yang, Tong; Deng, Yuting; Liu, Ya-Hong; Liu, Jian-Hua

    2012-12-07

    The aim of this study was to determine the presence of and characterize methicillin-resistant Staphylococcus pseudintermedius (MRSP) isolated from pets in South China. From 2007 to 2009, 898 samples were collected from 785 pets in Guangdong Province. The identity of staphylococcal species and the presence of methicillin resistance were confirmed by phenotypic and genotypic assays. The genetic relationships of MRSP isolates were determined by multilocus sequence typing (MLST), PFGE and spa typing. SCCmec elements and antimicrobial resistance genes profiling were characterized by PCR amplification. A total of 144 S. pseudintermedius isolates were recovered from the dogs and cats tested, and 69 (47.9%) of these isolates were identified as MRSP. Most of the MRSP isolates exhibited simultaneous resistance to four or more different antimicrobial agents. However, valnemulin showed robust activity against MRSP (MIC(90)=1 μg/ml). Integron 1, 2 and 3 were not detected in MRSP isolates. Twenty-four different multilocus sequence types were found among the MRSP isolates, with ST4 (n=9), ST5 (n=8), and ST95 (n=7) being dominant sequence types. In addition, 8 new sequence types (ST134, 135, 136, 137, 138, 139, 140 and 148) were identified. Of the 69 MRSP isolates, SCCmecV was the most prevalent type (n=33), followed by SCCmecVII (n=13), SCCmecII-III (n=7), and SCCmecIII (n=4). This study demonstrates for the first time that the occurrence of MRSP in healthy pets in China and shows that MRSP in South China has high genetic diversity.

  15. Evaluation of chromogenic media for detection of methicillin-resistant Staphylococcus aureus.

    PubMed

    Malhotra-Kumar, Surbhi; Abrahantes, José Cortinas; Sabiiti, Wilber; Lammens, Christine; Vercauteren, Greetje; Ieven, Margareta; Molenberghs, Geert; Aerts, Marc; Goossens, Herman

    2010-04-01

    Rapid laboratory diagnosis is critical for treating, managing, and preventing methicillin-resistant Staphylococcus aureus (MRSA) infections. We evaluated and compared the potential for MRSA detection of five chromogenic media, Brilliance MRSA agar (Oxoid), ChromID (bioMérieux), MRSASelect (Bio-Rad), CHROMagar (CHROMagar Microbiology), and BBL-CHROMagar (BD Diagnostics). Media were tested with log serial dilutions (10(0) to 10(6) CFU) of pure isolates of MRSA (n = 60), non-MRSA (n = 27), and defined mixtures thereof simulating clinical samples (n = 84). Further evaluations were done on pre-enriched nasal and groin screening swabs (n = 213) from 165 hospitalized patients. Randomized samples were spiral plated on each medium and independently scored by five investigators for characteristic colonies at 24 and 48 h of incubation. Confirmatory testing of up to five putative MRSA colonies recovered from each medium was done. The cumulative average sensitivity with isolates, mixtures, and clinical samples was the highest for Brilliance MRSA agar (97%) and similar for the other four media (>or=92%). The cumulative average specificity was the highest for BBL-CHROMagar (99%), followed by MRSASelect (98%), CHROMagar (97%), ChromID (89%), and Brilliance MRSA agar (86%). All of the media detected MRSA at 10 and 1 CFU, although at these low loads, few MRSA samples harboring SCCmec type III or IV were misinterpreted as non-MRSA by investigators. False-positive results were mainly due to methicillin-resistant S. epidermidis. For an arbitrary MRSA prevalence of 5% and based on patient sample evaluations, the positive predictive values for BBL-CHROMagar and CHROMagar ( approximately 84%) were the highest. The negative predictive values of all of the media were >or=92% for MRSA prevalences ranging from 5% to 30%. In conclusion, BBL-CHROMagar and CHROMagar gave the best overall results for detection of MRSA, irrespective of the sample concentration, investigator, or incubation period.

  16. Spectra MRSA, a New Chromogenic Agar Medium To Screen for Methicillin-Resistant Staphylococcus aureus▿

    PubMed Central

    Peterson, Jess F.; Riebe, Katherine M.; Hall, Gerri S.; Wilson, Deborah; Whittier, Susan; Palavecino, Elizabeth; Ledeboer, Nathan A.

    2010-01-01

    A novel chromogenic medium, Spectra MRSA (Remel, Lenexa, KS), was designed to detect methicillin-resistant Staphylococcus aureus (MRSA) rapidly and more efficiently than traditional media (i.e., tryptic soy agar with 5% sheep blood [SBA] and mannitol salt agar [MSA]). A multicenter study (including four clinical trial sites and the Medical College of Wisconsin [MCW] Milwaukee, WI) compared the performance characteristics of Spectra MRSA to those of the traditional media for the detection of MRSA. For this study, 767 nasal swab specimens from the multicenter study (traditional medium used, SBA) and 667 nasal swab specimens from MCW (traditional medium used, MSA) were plated on each test medium and examined after 24 and 48 h of incubation. At 24 h, the sensitivity and the specificity of each medium were as follows: in the multicenter study, 95.4% and 99.7%, respectively, for Spectra MRSA and 93.6% and 100%, respectively, for SBA; at MCW, 95.2% and 99.5%, respectively, for Spectra MRSA and 88.7% and 94.0%, respectively, for MSA. The positive predictive values of each medium at 24 h were as follows: in the multicenter study, 98.1% for Spectra MRSA and 100% for SBA; at MCW, 95.2% for Spectra MRSA and 60.4% for MSA. In our evaluation, we found that Spectra MRSA was able to rapidly identify and differentiate methicillin-resistant S. aureus from methicillin-susceptible S. aureus on the basis of the utilization of chromogens that result in denim blue colonies, thus eliminating the need for biochemical analysis and antimicrobial susceptibility testing. Extending the incubation beyond 24 h did not significantly improve the recovery of MRSA and resulted in decreased specificity. PMID:19889898

  17. Nasal carriage of methicillin-resistant Staphylococcus aureus and the effect of tea extracts on isolates.

    PubMed

    Abaza, Amani F; Mohamed, Osama N; El-Fiky, Fathy K; Ahmed, Khaled A

    2016-09-01

    This study aimed to determine the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage among patients, healthcare workers (HCWs), and community individuals, as well as to test the effect of tea extracts on detected S. aureus isolates. This cross-sectional study that was followed by an experimental study included a total of 1021 nasal swab samples that were collected from 470 community cases, 191 HCWs, and 360 patients. Isolation of S. aureus and MRSA was carried out on mannitol salt agar plates. S. aureus isolates were identified according to standard microbiological methods. Methicillin resistance was determined by disc-diffusion method according to the Clinical and Laboratory Standard Institute recommendations. A total of six tea samples (black and green) were purchased from different markets in Alexandria and were extracted. The antibacterial effects of these tea extracts were tested against identified MRSA isolates using agar gel diffusion method. The overall S. aureus nasal carriage rate was 12.5%, distributed as 7.9% MRSA and 4.6% methicillin-susceptible S. aureus. The rates of MRSA nasal carriage among HCWs, patients, and community cases were 10.5, 8.1, and 6.8%, respectively. Green tea had a strong effect on more than half of the isolates (55%) and an intermediate effect on 45% of them. It had no weak effect on any of the MRSA isolates. Among all tested individuals, HCWs had the highest percentage of MRSA nasal carriage. Green tea had a significantly stronger inhibitory effect than black tea on almost all tested isolates.

  18. Effectiveness of hand-cleansing agents for removing methicillin-resistant Staphylococcus aureus from contaminated hands.

    PubMed

    Guilhermetti, M; Hernandes, S E; Fukushigue, Y; Garcia, L B; Cardoso, C L

    2001-02-01

    The effectiveness of hand-cleansing agents in removing a hospital strain of methicillin-resistant Staphylococcus aureus from artificially contaminated hands of five volunteers was studied. The products used were plain liquid soap, ethyl alcohol 70% (by weight), 10% povidone-iodine liquid soap (PVP-I), and chlorhexidine gluconate (4%) detergent. The experiments were performed using a Latin square statistical design, with two 5x4 randomized blocks. The removal rates of S aureus cells from contaminated fingertips were estimated by analysis of variance, the response variable being the log10 reduction factor (RF), ie, log10 of the initial counts minus log10 of the final counts. In the first and second blocks, the fingertips of the volunteers were contaminated in mean with 3.76 log10 colony-forming units ([CFU] light-contamination hand) and 6.82 log10 CFU (heavy-contamination hand), respectively. In the first block, there were significant differences between treatments (P<.05). The 10% PVP-I (RF, 3.76) and 70% ethyl alcohol (RF, 3.51) had significantly higher removal rates than plain liquid soap (RF, 1.96) and 4% chlorhexidine (RF, 1.91). In the second block, 10% PVP-I (RF, 4.39) and 70% ethyl alcohol (RF, 3.27) also were significantly more effective than plain liquid soap (RF, 1.77) and 4% chlorhexidine (RF, 1.37; P<.05). Plain liquid soap was significantly more effective than chlorhexidine (4%) detergent. The results suggest that 10% PVP-I and 70% ethyl alcohol may be the most effective hand-cleansing agents for removing methicillin-resistant S aureus strain from either lightly or heavily contaminated hands.

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

    PubMed

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

    2015-01-01

    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. 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. 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. 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 revealed a likely loss of viability as a result of the

  20. 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

  1. Microbial Susceptibility and Plasmid Profiles of Methicillin-Resistant Staphylococcus aureus and Methicillin-Susceptible S. aureus

    PubMed Central

    Shahkarami, Fatemeh; Rashki, Ahmad; Rashki Ghalehnoo, Zahra

    2014-01-01

    Background: Today, significant increase in the prevalence and emergence of methicillin-resistant Staphylococcus aureus (MRSA) is a serious public health concern and is likely to have a dramatic negative impact on many current medical practices. Therefore, identification of MRSA strains is important for both clinical and epidemiological implications. Objectives: The present study was carried out to determine the frequency of methicillin resistant; antibiotic susceptibility and plasmid profiles of S. aureus recovered from different types of clinical samples of patients in Zabol, Iran. Material and Methods: Clinical samples from 500 outpatient and hospitalized patients were tested for S. aureus. The susceptibility of 106 S. aureus to 11 antibiotics was evaluated by the disk diffusion method and Etest oxacillin strips. The presence of mecA gene was investigated by polymerase chain reaction (PCR). The plasmid profile patterns of all isolates were determined by a modified alkaline lysis method. Results: A total of 67 (63.20%) strains were found to be MRSA isolates. Most of MRSA isolates showed high level of resistance to ampicillin, erythromycin, nalidixic acid, penicillin, and tetracycline. Twenty-six percent of MRSA isolates showed high level of resistance to oxacillin (minimum inhibitory concentration [MIC] ≥ 256 μg/mL). mecA gene was detected among 62 MRSA isolates. Totally, 75 isolates of both strains harbored plasmid. Conclusions: Resistance to oxacillin and other antibiotics was high, and most of the isolates were found to be multi-drug resistance (MDR). Plasmid analysis of representative S. aureus isolates also demonstrates the presence of a wide range of plasmid sizes, with no consistent relationship between plasmid profiles and resistance phenotypes. Regular surveillance of hospital infections and monitoring of their antibiotic sensitivity patterns are required to reduce MRSA prevalence. High prevalence and multi-drug resistance of MRSA isolates in southeast

  2. Treatment of experimental endocarditis due to erythromycin-susceptible or -resistant methicillin-resistant Staphylococcus aureus with RP 59500.

    PubMed

    Entenza, J M; Drugeon, H; Glauser, M P; Moreillon, P

    1995-07-01

    RP 59500 is a new injectable streptogramin composed of two synergistic components (quinupristin and dalfopristin) which are active against erythromycin-susceptible and -resistant gram-positive pathogens. The present experiments compared the therapeutic efficacy of RP 59500 with that of vancomycin against experimental endocarditis due to either of two erythromycin-susceptible or two constitutively erythromycin-resistant isolates of methicillin-resistant Staphylococcus aureus. RP 59500 had low MICs for the four test organisms as well as for 24 additional isolates (the MIC at which 90% of the isolates were inhibited was < 1 mg/liter) which were mostly inducibly (47%) or constitutively (39%) erythromycin resistant. Aortic endocarditis in rats was produced with catheter-induced vegetations. Three-day therapy was initiated 12 h after infection, and the drugs were delivered via a computerized pump, which permitted the mimicking of the drug kinetics produced in human serum by twice-daily intravenous injections of 7 mg of RP 59500 per kg of body weight or 1 g of vancomycin. Both antibiotics reduced vegetation bacterial titers to below detection levels in ca. 70% of animals infected with the erythromycin-susceptible isolates (P < 0.05 compared with titers in controls). Vancomycin was also effective against the constitutively resistant strains, but RP 59500 failed against these isolates. Further experiments proved that RP 59500 failures were related to the very short life span of dalfopristin in serum (< or = 2 h, compared with > or = 6 h for quinupristin), since successful treatment was restored by artificially prolonging the dalfopristin levels for 6 h. Thus, RP 59500 is a promising alternative to vancomycin against methicillin-resistant S. aureus infections, provided that pharmacokinetic parameters are adjusted to afford prolonged levels of both of its constituents in serum. This observation is also relevant to humans, in whom the life span of dalfopristin in serum is also

  3. Evaluation of Antibiotics Active against Methicillin-Resistant Staphylococcus aureus Based on Activity in an Established Biofilm

    PubMed Central

    Meeker, Daniel G.; Beenken, Karen E.; Mills, Weston B.; Loughran, Allister J.; Spencer, Horace J.; Lynn, William B.

    2016-01-01

    We used in vitro and in vivo models of catheter-associated biofilm formation to compare the relative activity of antibiotics effective against methicillin-resistant Staphylococcus aureus (MRSA) in the specific context of an established biofilm. The results demonstrated that, under in vitro conditions, daptomycin and ceftaroline exhibited comparable activity relative to each other and greater activity than vancomycin, telavancin, oritavancin, dalbavancin, or tigecycline. This was true when assessed using established biofilms formed by the USA300 methicillin-resistant strain LAC and the USA200 methicillin-sensitive strain UAMS-1. Oxacillin exhibited greater activity against UAMS-1 than LAC, as would be expected, since LAC is an MRSA strain. However, the activity of oxacillin was less than that of daptomycin and ceftaroline even against UAMS-1. Among the lipoglycopeptides, telavancin exhibited the greatest overall activity. Specifically, telavancin exhibited greater activity than oritavancin or dalbavancin when tested against biofilms formed by LAC and was the only lipoglycopeptide capable of reducing the number of viable bacteria below the limit of detection. With biofilms formed by UAMS-1, telavancin and dalbavancin exhibited comparable activity relative to each other and greater activity than oritavancin. Importantly, ceftaroline was the only antibiotic that exhibited greater activity than vancomycin when tested in vivo in a murine model of catheter-associated biofilm formation. These results emphasize the need to consider antibiotics other than vancomycin, most notably, ceftaroline, for the treatment of biofilm-associated S. aureus infections, including by the matrix-based antibiotic delivery methods often employed for local antibiotic delivery in the treatment of these infections. PMID:27401574

  4. Tandem Amplification of the Staphylococcal Cassette Chromosome mec Element Can Drive High-Level Methicillin Resistance in Methicillin-Resistant Staphylococcus aureus.

    PubMed

    Gallagher, Laura A; Coughlan, Simone; Black, Nikki S; Lalor, Pierce; Waters, Elaine M; Wee, Bryan; Watson, Mick; Downing, Tim; Fitzgerald, J Ross; Fleming, Gerard T A; O'Gara, James P

    2017-09-01

    Hospital-associated methicillin-resistant Staphylococcus aureus (MRSA) strains typically express high-level, homogeneous (HoR) β-lactam resistance, whereas community-associated MRSA (CA-MRSA) more commonly express low-level heterogeneous (HeR) resistance. Expression of the HoR phenotype typically requires both increased expression of the mecA gene, carried on the staphylococcal cassette chromosome mec element (SCCmec), and additional mutational event(s) elsewhere on the chromosome. Here the oxacillin concentration in a chemostat culture of the CA-MRSA strain USA300 was increased from 8 μg/ml to 130 μg/ml over 13 days to isolate highly oxacillin-resistant derivatives. A stable, small-colony variant, designated HoR34, which had become established in the chemostat culture was found to have acquired mutations in gdpP, clpX, guaA, and camS Closer inspection of the genome sequence data further revealed that reads covering SCCmec were ∼10 times overrepresented compared to other parts of the chromosome. Quantitative PCR (qPCR) confirmed >10-fold-higher levels of mecA DNA on the HoR34 chromosome, and MinION genome sequencing verified the presence of 10 tandem repeats of the SCCmec element. qPCR further demonstrated that subculture of HoR34 in various concentrations of oxacillin (0 to 100 μg/ml) was accompanied by accordion-like contraction and amplification of the SCCmec element. Although slower growing than strain USA300, HoR34 outcompeted the parent strain in the presence of subinhibitory oxacillin. These data identify tandem amplification of the SCCmec element as a new mechanism of high-level methicillin resistance in MRSA, which may provide a competitive advantage for MRSA under antibiotic selection. Copyright © 2017 American Society for Microbiology.

  5. In vitro antibacterial activity of TOC-50, a new parenteral cephalosporin against methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis.

    PubMed

    Nomura, S; Hanaki, H; Unemi, N

    1996-01-01

    The in vitro activity of TOC-50, a new parenteral cephalosporin, was assessed against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE). TOC-50 showed excellent activity, which was stronger than that of methicillin, cloxacillin, the cephalosporins tested, imipenem, gentamycin, minocycline, ofloxacin and ciprofloxacin against MRSA and had a minimum inhibitory concentration (MIC) comparable to that of vancomycin (the MICs of TOC-50 and vancomycin for growth inhibition of 90% of the strains tested were 3.13 and 1.56 micrograms/ml, respectively). Against MRSE, TOC-50 exhibited excellent activity, which was stronger than that of methicillin, ampicillin, the cephalosporins tested and imipenem, and was twice as active as vancomycin. In terms of the bactericidal effect against MRSA, TOC-50 was superior to vancomycin.

  6. Comparison of bactericidal activities of various disinfectants against methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus.

    PubMed

    Yasuda, T; Yoshimura, S; Katsuno, Y; Takada, H; Ito, M; Takahashi, M; Yahazaki, F; Iriyama, J; Ishigo, S; Asano, Y

    1993-01-01

    Various disinfectants were compared in terms of the duration of bactericidal activity against methicillin-sensitive Staphylococcus aureus (MSSA), and methicillin-resistant Staphylococcus aureus (MRSA), among S. aureus isolated in our hospital. Strains of S. aureus which showed minimum inhibitory concentrations of cloxacillin of less than 1.56 micrograms/ml and of 3.13 micrograms/ml or higher were designated MSSA and MRSA respectively. There was no difference in sensitivity to disinfectants between MSSA and MRSA. There was a great variation in the duration of bactericidal activity of chlorhexidine gluconate against these species with the majority requiring contact times of between 2 minutes and over 20 minutes. All strains except for one strain of MRSA were killed within 20 seconds after disinfection with benzalkonium chloride. All strains were killed within 20 seconds after disinfection with alkyldiaminoethylglycine hydrochloride or povidone-iodine.

  7. Inhibition of the Carpobrotus edulis methanol extract on the growth of phagocytosed multidrug-resistant Mycobacterium tuberculosis and methicillin-resistant Staphylococcus aureus.

    PubMed

    Martins, Marta; Ordway, Diane; Kristiansen, Malthe; Viveiros, Miguel; Leandro, Clara; Molnar, Joseph; Amaral, Leonard

    2005-01-01

    The Carpobrotus edulis methanol extract, inactive against the methicillin-resistant Staphylococcus aureus or the multidrug-resistant Mycobacterium tuberculosis, does inhibit the growth of these two bacteria once they are phagocytosed by monocyte derived human macrophages.

  8. Methicillin-resistant Staphylococcus aureus: an emerging pathogen of pets in Egypt with a public health burden.

    PubMed

    Abdel-moein, K A; El-Hariri, M; Samir, A

    2012-08-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged to be a pathogen of public health burden causing infections with significant concern. This study was conducted to investigate methicillin-resistant Staphylococcus aureus (MRSA) infection in pet dogs and cats as an emerging zoonosis that could be disseminated in the community. A total of 184 (nasal, oral, ear and wound) swabs were collected from 70 pet dogs and 48 pet cats, whereas 50 nasal and oral swabs were collected from 28 apparently healthy companion persons in intimate contact with pets and without history of hospitalization. All samples were cultured for the isolation and identification of Staphylococcus aureus using selective media, biochemical and serological tests, while isolates were identified as MRSA after antimicrobial susceptibility testing and determination of the MIC. PCR was applied using specific primers to confirm MRSA. Three MRSA isolates have been recovered from two dogs of 70 (2.9%) and one isolate from 28 examined persons (3.6%), while none of the examined cats yielded MRSA. Furthermore, we found that two MRSA isolates recovered from one diseased dog seemed to be hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA), whereas the other dog isolate as well as the human isolate were considered as community-acquired (CA-MRSA). The occurrence of MRSA in apparently healthy and/or diseased pet dogs makes it an emerging veterinary pathogen which could be considered a public health burden if it is disseminated in our community outside hospitals.

  9. Bacteriological profiling of diphenylureas as a novel class of antibiotics against methicillin-resistant Staphylococcus aureus.

    PubMed

    Mohammad, Haroon; Younis, Waleed; Ezzat, Hany G; Peters, Christine E; AbdelKhalek, Ahmed; Cooper, Bruce; Pogliano, Kit; Pogliano, Joe; Mayhoub, Abdelrahman S; Seleem, Mohamed N

    2017-01-01

    Bacterial resistance to antibiotics remains an imposing global public health challenge. Of the most serious pathogens, methicillin-resistant Staphylococcus aureus (MRSA) is problematic given strains have emerged that exhibit resistance to several antibiotic classes including β-lactams and agents of last resort such as vancomycin. New antibacterial agents composed of unique chemical scaffolds are needed to counter this public health challenge. The present study examines two synthetic diphenylurea compounds 1 and 2 that inhibit growth of clinically-relevant isolates of MRSA at concentrations as low as 4 µg/mL and are non-toxic to human colorectal cells at concentrations up to 128 μg/mL. Both compounds exhibit rapid bactericidal activity, completely eliminating a high inoculum of MRSA within four hours. MRSA mutants exhibiting resistance to 1 and 2 could not be isolated, indicating a low likelihood of rapid resistance emerging to these compounds. Bacterial cytological profiling revealed the diphenylureas exert their antibacterial activity by targeting bacterial cell wall synthesis. Both compounds demonstrate the ability to resensitize vancomycin-resistant Staphylococcus aureus to the effect of vancomycin. The present study lays the foundation for further investigation and development of diphenylurea compounds as a new class of antibacterial agents.

  10. Staphylococcus aureus methicillin resistance detected by HPLC-MS/MS targeted metabolic profiling.

    PubMed

    Schelli, Katie; Rutowski, Joshua; Roubidoux, Julia; Zhu, Jiangjiang

    2017-03-15

    Recently, novel bioanalytical methods, such as NMR and mass spectrometry based metabolomics approaches, have started to show promise in providing rapid, sensitive and reproducible detection of Staphylococcus aureus antibiotic resistance. Here we performed a proof-of-concept study focused on the application of HPLC-MS/MS based targeted metabolic profiling for detecting and monitoring the bacterial metabolic profile changes in response to sub-lethal levels of methicillin exposure. One hundred seventy-seven targeted metabolites from over 20 metabolic pathways were specifically screened and one hundred and thirty metabolites from in vitro bacterial tests were confidently detected from both methicillin susceptible and methicillin resistant Staphylococcus aureus (MSSA and MRSA, respectively). The metabolic profiles can be used to distinguish the isogenic pairs of MSSA strains from MRSA strains, without or with sub-lethal levels of methicillin exposure. In addition, better separation between MSSA and MRSA strains can be achieved in the latter case using principal component analysis (PCA). Metabolite data from isogenic pairs of MSSA and MRSA strains were further compared without and with sub-lethal levels of methicillin exposure, with metabolic pathway analyses additionally performed. Both analyses suggested that the metabolic activities of MSSA strains were more susceptible to the perturbation of the sub-lethal levels of methicillin exposure compared to the MRSA strains.

  11. Identification of virulence genes carried by bacteriophages obtained from clinically isolated methicillin-resistant Staphylococcus aureus.

    PubMed

    Karasartova, Djursun; Cavusoglu, Zeynep Burcin; Turegun, Buse; Ozsan, Murat T; Şahin, Fikret

    2016-12-01

    Bacteriophages play an important role in the pathogenicity of Staphylococcus aureus (S. aureus) either by carrying accessory virulence factors or several superantigens. Despite their importance, there are not many studies showing the actual distribution of the virulence genes carried by the prophages obtained from the clinically isolated Staphylococcus. In this study, we investigated prophages obtained from methicillin-resistant S. aureus (MRSA) strains isolated from hospital- and community-associated (HA-CA) infections for the virulence factors. In the study, 43 phages isolated from 48 MRSA were investigated for carrying toxin genes including the sak, eta, lukF-PV, sea, selp, sek, seg, seq chp, and scn virulence genes using polymerase chain reaction (PCR) and Southern blot. Restriction fragment length polymorphism was used to analyze phage genomes to investigate the relationship between the phage profiles and the toxin genes' presence. MRSA strains isolated from HA infections tended to have higher prophage presence than the MRSA strains obtained from the CA infections (97% and 67%, respectively). The study showed that all the phages with the exception of one phage contained one or more virulence genes in their genomes with different combinations. The most common toxin genes found were sea (83%) followed by sek (77%) and seq (64%). The study indicates that prophages encode a significant proportion of MRSA virulence factors.

  12. Modeling Nosocomial Infections of Methicillin-Resistant Staphylococcus aureus with Environment Contamination().

    PubMed

    Wang, Lei; Ruan, Shigui

    2017-04-03

    In this work, we investigate the role of environmental contamination on the clinical epidemiology of antibiotic-resistant bacteria in hospitals. Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that causes infections in different parts of the body. It is tougher to treat than most strains of Staphylococcus aureus or staph, because it is resistant to some commonly used antibiotics. Both deterministic and stochastic models are constructed to describe the transmission characteristics of MRSA in hospital setting. The deterministic epidemic model includes five compartments: colonized and uncolonized patients, contaminated and uncontaminated health care workers (HCWs), and bacterial load in environment. The basic reproduction number R 0 is calculated, and its numerical and sensitivity analysis has been performed to study the asymptotic behavior of the model, and to help identify factors responsible for observed patterns of infections. A stochastic epidemic model with stochastic simulations is also presented to supply a comprehensive analysis of its behavior. Data collected from Beijing Tongren Hospital will be used in the numerical simulations of our model. The results can be used to provide theoretical guidance for designing efficient control measures, such as increasing the hand hygiene compliance of HCWs and disinfection rate of environment, and decreasing the transmission rate between environment and patients and HCWs.

  13. Evolving Rapid Methicillin-resistant Staphylococcus aureus Detection: Cover All the Bases

    PubMed Central

    Bakthavatchalam, Yamuna Devi; Nabarro, Laura E B; Veeraraghavan, Balaji

    2017-01-01

    The dissemination of methicillin-resistant (MR) Staphylococcus aureus (SA) in community and health-care settings is of great concern and associated with high mortality and morbidity. Rapid detection of MRSA with short turnaround time can minimize the time to initiate appropriate therapy and further promote infection control. Early detection of MRSA directly from clinical samples is complicated by the frequent association of MRSA with methicillin-susceptible SA (MSSA) and coagulase-negative Staphylococcus (CoNS) species. Infection associated with true MRSA or MSSA is differentiated from CoNS, requires target specific primers for the presence of SA and mec A or nuc or fem A gene for confirmation of MR. Recently, livestock-associated MRSA carrying mec C variant complicates the epidemiology of MRSA further. Several commercial rapid molecular kits are available with a different combination of these targets for the detection of MRSA or MSSA. The claimed sensitivity and specificity of the currently available commercial kits is varying, because of the different target combination used for detection of SA and MR. PMID:28250621

  14. Risk factors for methicillin-resistant Staphylococcus aureus bacteraemia differ depending on the control group chosen

    PubMed Central

    POGORZELSKA-MAZIARZ, M.; FURUYA, E. Y.; LARSON, E. L.

    2014-01-01

    SUMMARY Methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia cause significant morbidity and mortality in hospitalized patients. Using a nested case-control design, 204 MRSA bacteraemia cases were compared to 301 unmatched methicillin-susceptible Staphylococcus aureus (MSSA) bacteraemia controls and were matched 1:2 with non-infected controls. The independent risk factors for MRSA bacteraemia compared to MSSA bacteraemia were older age (P=0·048), major organ transplant during current hospital stay (P=0·016) and quinolone use (P=0·016). Cases were more likely than non-infected controls to have renal failure (P=0·003), cirrhosis (P=0·013), and a central venous catheter (P=0·003) after controlling for other risk factors. This large case-control study made it possible to assess risk factors for MRSA bacteraemia using two sets of controls and showed that risk factors differed greatly depending on the control group chosen. These results confirm the need for careful selection of appropriate control groups and the need to carefully adjust for underlying severity of illness. PMID:23425708

  15. IsaB inhibits autophagic flux to promote host transmission of methicillin-resistant Staphylococcus aureus

    PubMed Central

    Liu, Pei-Feng; Cheng, Jin-Shiung; Sy, Cheng-Len; Huang, Wei-Chun; Yang, Hsiu-Chen; Gallo, Richard L.; Huang, Chun-Ming; Shu, Chih-Wen

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major nosocomial pathogen that is widespread in both health care facilities and the community at large as a result of direct host-to-host transmission. Several virulence factors are associated with pathogen transmission to naive hosts. Immunodominant surface antigen B (IsaB) is a virulence factor that helps Staphylococcus aureus to evade the host defense system. However, the mechanism of IsaB on host transmissibility remains unclear. We found that IsaB expression was elevated in transmissible MRSA. Wild-type isaB strains inhibited autophagic flux to promote bacterial survival and elicit inflammation in THP-1 cells and mouse skin. MRSA isolates with increased IsaB expression showed decreased autophagic flux, and the MRSA isolate with the lowest IsaB expression showed increased autophagic flux. In addition, recombinant IsaB rescued the virulence of the isaB deletion strain and increased the Group A streptococcus (GAS) virulence in vivo. Together, these results reveal that IsaB diminishes autophagic flux, thereby allowing MRSA to evade host degradation. These findings suggest that IsaB is a suitable target for preventing or treating MRSA infection. PMID:26134948

  16. A study of the prevalence of methicillin-resistant Staphylococcus aureus in dermatology inpatients

    PubMed Central

    Vijayamohan, N.; Nair, S. Pradeep

    2014-01-01

    Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a cause of increased morbidity and mortality in debilitated and immunocompromised patients. Aims and Objectives: To study the prevalence of MRSA among dermatology inpatients and elucidate its predisposing factors and antibiotic sensitivity pattern. Materials and Methods: This prospective study involved all the inpatients in the dermatology ward with suspected bacterial infections, both primary and secondary. Gram's stain, pus culture, and antibiotic sensitivity were the main tests done. Results: There were 61 patients in this study, with 36 males (59%) and 25 females (41%). The age group maximally affected was 41-50 years (21.6%). Vesiculobullous disorders (22, 36.1%) and eczemas (16, 26.2%) were the commonest dermatoses with secondary infection. Extremities (72.1%) and the trunk (26.2%) were the commonest sites involved. Diabetes mellitus (DM) was the commonest systemic illness (11.5%). Staphylococcus aureus was the commonest isolate, grown in 52 patients (85.2%) of whom 16 (30.80%) were MRSA positive. MRSA constituted 22.2% of the total bacterial isolates. All the MRSA isolates (100%) were resistant to cloxacillin and oxacillin, while all the isolates (100%) were sensitive to vancomycin and linezolid. Conclusions: The prevalence of MRSA in this study was high. It was most commonly seen in patients with vesiculobullous disorders. A high sensitivity of MRSA was found to amikacin. There was no relation between prolonged antibiotic therapy and MRSA in this study. PMID:25396125

  17. Risk factors for nosocomial bacteremia due to methicillin-resistant Staphylococcus aureus.

    PubMed

    Pujol, M; Peña, C; Pallares, R; Ayats, J; Ariza, J; Gudiol, F

    1994-01-01

    In a prospective surveillance study (February 1990-December 1991) performed at a 1000-bed teaching hospital to identify risk factors for nosocomial methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, 309 patients were found to be colonized (n = 103; 33%) or infected (n = 206; 67%) by MRSA. Sixty-three of them developed bacteremia. Compared with 114 patients who had nosocomial bacteremia caused by methicillin-sensitive Staphylococcus aureus during the same period of time, MRSA bacteremic patients had more severe underlying diseases (p < 0.01), were more often in intensive care units (p < 0.01) and had received prior antibiotic therapy more frequently (p < 0.01). To further identify risk factors for MRSA bacteremia, univariate and multivariate analyses of this series of 309 patients were performed using the occurrence of MRSA bacteremia as the dependent variable. Among 14 variables analyzed, intravascular catheterization, defined as one or more intravascular catheters in place for more than 48 h, was the only variable selected by a logistic regression model as an independent risk factor (OR = 2.7, CI = 1.1-6.6). The results of this study reinforce the concept that recent antibiotic therapy may predispose patients to MRSA infection and suggest that among patients colonized or infected by MRSA, those with intravascular catheters are at high risk of developing MRSA bacteremia.

  18. The inhibitory potential of Thai mango seed kernel extract against methicillin-resistant Staphylococcus aureus.

    PubMed

    Jiamboonsri, Pimsumon; Pithayanukul, Pimolpan; Bavovada, Rapepol; Chomnawang, Mullika T

    2011-07-25

    Plant extracts are a valuable source of novel antibacterial compounds to combat pathogenic isolates of methicillin-resistant Staphylococcus aureus (MRSA), a global nosocomial infection. In this study, the alcoholic extract from Thai mango (Mangifera indica L. cv. 'Fahlun') seed kernel extract (MSKE) and its phenolic principles (gallic acid, methyl gallate and pentagalloylglucopyranose) demonstrated potent in vitro antibacterial activity against Staphylococcus aureus and 19 clinical MRSA isolates in studies of disc diffusion, broth microdilution and time-kill assays. Electron microscopy studies using scanning electron microscopy and transmission electron microscopy revealed impaired cell division and ultra-structural changes in bacterial cell morphology, including the thickening of cell walls, of microorganisms treated with MSKE; these damaging effects were increased with increasing concentrations of MSKE. MSKE and its phenolic principles enhanced and intensified the antibacterial activity of penicillin G against 19 clinical MRSA isolates by lowering the minimum inhibitory concentration by at least 5-fold. The major phenolic principle, pentagalloylglucopyranose, was demonstrated to be the major contributor to the antibacterial activity of MSKE. These results suggest that MSKE may potentially be useful as an alternative therapeutic agent or an adjunctive therapy along with penicillin G in the treatment of MRSA infections.

  19. Anti bacterial activity of Nigella sativa against clinical isolates of methicillin resistant Staphylococcus aureus.

    PubMed

    Hannan, Abdul; Saleem, Sidrah; Chaudhary, Saadia; Barkaat, Muhammad; Arshad, Muhammad Usman

    2008-01-01

    Methicillin resistant Staphylococcus aureus (MRSA) continues to be one of the commonest pathogens encountered in clinical as well as laboratory practice. It has become a major health problem worldwide. Newer antimicrobials/agents are urgently needed to combat this problem MRSA resistance to various anti-staphylococcal agents. In the back-drop of this difficult situation Nigella sativa commonly known as black seed (ethanolic extract) was aimed at to evaluate if it had any anti-staphylococcal activity. The extract was prepared by reflux extraction method. Disc diffusion and in agar dilution methods were performed to assess the antibacterial activity. Staphylococcus aureus ATCC 25923 was used as the standard reference strain. All tested strains of MRSA were sensitive to N. sativa extract at a concentration of 4 mg/disc while the extract had an MIC range of 0.2-0.5 mg/ml. The results indicated that N. sativa has inhibitory effect on MRSA. This finding warrants necessity of further investigation of this product of folk medicine.

  20. [Economic burden of methicillin-resistant Staphylococcus aureus bacteremia in critical care patients in hospitals in Bogotá].

    PubMed

    Barrero, Liliana I; Castillo, Juan S; Leal, Aura L; Sánchez, Ricardo; Cortés, Jorge A; Alvarez, Carlos A; González, Andrés L

    2014-01-01

    Resistant infections, especially those involving the bloodstream, are associated with a greater use of resources. Their estimates are variable and depend on the methodology used. Staphylococcus aureus is the main pathogen isolated in blood in our hospitals. There is no consolidated data about economic implications of methicillin-resistant S. aureus infection. To describe the cost of care of methicillin-resistant S. aureus bacteremia in a reference population from nine hospitals in Bogotá. Materials y methods: A multicenter cohort study included 204 patients in a 1:1 ratio according to resistance. Direct medical costs were calculated from hospitalization bills, while the bacteremia period was calculated by applying microcosting based on standard fares. We found no significant differences between groups in demographic and clinical characteristics, except for resistance risk factors. Fifty-three percent of patients died during hospitalization. Hospital stay and total invoiced value during hospitalization were significantly higher in the group with methicillin-resistant S. aureus bacteremia. For this group, higher costs in ICU stay, antibiotics use, intravenous fluids, laboratory tests and respiratory support were recorded. A crude increase of 31% and an adjusted increase of 70% in care costs associated with methicillin resistance were registered. Our study supports decision makers in finding and funding infection prevention programs, especially those infections caused by resistant organisms.

  1. The Plasmin-Sensitive Protein Pls in Methicillin-Resistant Staphylococcus aureus (MRSA) Is a Glycoprotein

    PubMed Central

    Pohlentz, Gottfried; Xia, Guoqing; Hussain, Muzaffar; Foster, Simon; Peters, Georg

    2017-01-01

    Most bacterial glycoproteins identified to date are virulence factors of pathogenic bacteria, i.e. adhesins and invasins. However, the impact of protein glycosylation on the major human pathogen Staphylococcus aureus remains incompletely understood. To study protein glycosylation in staphylococci, we analyzed lysostaphin lysates of methicillin-resistant Staphylococcus aureus (MRSA) strains by SDS-PAGE and subsequent periodic acid-Schiff’s staining. We detected four (>300, ∼250, ∼165, and ∼120 kDa) and two (>300 and ∼175 kDa) glycosylated surface proteins with strain COL and strain 1061, respectively. The ∼250, ∼165, and ∼175 kDa proteins were identified as plasmin-sensitive protein (Pls) by mass spectrometry. Previously, Pls has been demonstrated to be a virulence factor in a mouse septic arthritis model. The pls gene is encoded by the staphylococcal cassette chromosome (SCC)mec type I in MRSA that also encodes the methicillin resistance-conferring mecA and further genes. In a search for glycosyltransferases, we identified two open reading frames encoded downstream of pls on the SCCmec element, which we termed gtfC and gtfD. Expression and deletion analysis revealed that both gtfC and gtfD mediate glycosylation of Pls. Additionally, the recently reported glycosyltransferases SdgA and SdgB are involved in Pls glycosylation. Glycosylation occurs at serine residues in the Pls SD-repeat region and modifying carbohydrates are N-acetylhexosaminyl residues. Functional characterization revealed that Pls can confer increased biofilm formation, which seems to involve two distinct mechanisms. The first mechanism depends on glycosylation of the SD-repeat region by GtfC/GtfD and probably also involves eDNA, while the second seems to be independent of glycosylation as well as eDNA and may involve the centrally located G5 domains. Other previously known Pls properties are not related to the sugar modifications. In conclusion, Pls is a glycoprotein and Pls glycosyl

  2. Methicillin-resistant Staphylococcus aureus of lineage ST398 as cause of mastitis in cows.

    PubMed

    Silva, N C C; Guimarães, F F; Manzi, M P; Júnior, A Fernandes; Gómez-Sanz, E; Gómez, P; Langoni, H; Rall, V L M; Torres, C

    2014-12-01

    The objective of this study was to analyse the prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) in milk of cows with mastitis. The California mastitis test (CMT) was used to detect the presence of mastitis in all 100 cows of a farm in Brazil. The CMT was positive in milk of 115 mammary quarters from 36 cows (36%). MRSA isolates were recovered from 4 of these 36 cows with mastitis (11%), and they were further characterized (one MRSA/sample). The four MRSA isolates were typed as t011-ST398-agr1-SCCmecV and presented two different pulsed-field-gel-electrophoresis-ApaI patterns. These four MRSA isolates showed resistance to tetracycline, streptomycin and ciprofloxacin, carried the mecA, blaZ, tet(K), and tet(M) resistance genes, and presented the S84L and S80F amino acid substitutions in GyrA and GrlA proteins, respectively. Two ST398 isolates exhibited resistance to gentamicin and tobramycin [with aac(6)-aph(2") and ant(4)-Ia genes] and one isolate resistance to clindamycin [with lnu(B) and lsa(E) genes]; this latter isolate also carried the spectinomycin/streptomycin resistance genes spw and aadE. MRSA of lineage ST398 is worldwide spread, normally multidrug resistant and may be responsible for bovine mastitis. To our knowledge, this is the first detection of MRSA-ST398 in Brazil. Few studies on the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) from bovine isolates have been performed in Brazil. MRSA of lineage ST398 is worldwide spread and associated with farm animals. Multidrug-resistant MRSA-ST398 isolates were recovered in 11% of mastitic cows from a single farm, with one isolate carrying the unusual lsa(E), spw and aadE genes. To our knowledge, this is the first detection of MRSA-ST398 isolates in milk samples of cows with mastitis in Brazil. © 2014 The Society for Applied Microbiology.

  3. Methicillin-resistant Staphylococcus aureus: a controversial food-borne pathogen.

    PubMed

    Sergelidis, D; Angelidis, A S

    2017-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of severe healthcare-associated (HA) infections. Although during the last decade the incidence of HA invasive infections has dropped, the incidence of community-associated MRSA (CA-MRSA) infections has risen among the general population. Moreover, CA-MRSA, livestock-associated MRSA (LA-MRSA) and HA-MRSA (HA-MRSA) can be found in foods intended for human consumption. Several studies from different geographical areas have reported the presence of enterotoxin genes in several MRSA food isolates. Molecular typing studies have revealed genetic relatedness of these enterotoxigenic isolates with isolates incriminated in human infections. The contamination sources for foods, especially animal-origin foods, may be livestock as well as humans involved in animal husbandry and food-processing. Under favourable environmental conditions for growth and enterotoxin production, enterotoxigenic S. aureus isolates present in foods can cause staphylococcal food poisoning (SFP), irrespective of the contamination origin. Owing to the typically moderate clinical manifestations of SFP, the S. aureus strains responsible for SFP (cases or outbreaks) are frequently either not identified or not further characterized. Antimicrobial susceptibility testing is rarely performed, because administration of antimicrobial therapy is not required in the vast majority of cases. Staphylococcal food poisoning is the result of consumption of foods with preformed enterotoxins. Hence, similar to methicillin-sensitive enterotoxigenic S. aureus, enterotoxigenic MRSA can also act as food-borne pathogens upon favourable conditions for growth and enterotoxin production. The severity of the intoxication is not related to the antimicrobial resistance profile of the causative S. aureus strain and therefore MRSA food-borne outbreaks are not expected to be more severe. This review evaluates the potential of methicillin-resistant Staphylococcus

  4. The Plasmin-Sensitive Protein Pls in Methicillin-Resistant Staphylococcus aureus (MRSA) Is a Glycoprotein.

    PubMed

    Bleiziffer, Isabelle; Eikmeier, Julian; Pohlentz, Gottfried; McAulay, Kathryn; Xia, Guoqing; Hussain, Muzaffar; Peschel, Andreas; Foster, Simon; Peters, Georg; Heilmann, Christine

    2017-01-01

    Most bacterial glycoproteins identified to date are virulence factors of pathogenic bacteria, i.e. adhesins and invasins. However, the impact of protein glycosylation on the major human pathogen Staphylococcus aureus remains incompletely understood. To study protein glycosylation in staphylococci, we analyzed lysostaphin lysates of methicillin-resistant Staphylococcus aureus (MRSA) strains by SDS-PAGE and subsequent periodic acid-Schiff's staining. We detected four (>300, ∼250, ∼165, and ∼120 kDa) and two (>300 and ∼175 kDa) glycosylated surface proteins with strain COL and strain 1061, respectively. The ∼250, ∼165, and ∼175 kDa proteins were identified as plasmin-sensitive protein (Pls) by mass spectrometry. Previously, Pls has been demonstrated to be a virulence factor in a mouse septic arthritis model. The pls gene is encoded by the staphylococcal cassette chromosome (SCC)mec type I in MRSA that also encodes the methicillin resistance-conferring mecA and further genes. In a search for glycosyltransferases, we identified two open reading frames encoded downstream of pls on the SCCmec element, which we termed gtfC and gtfD. Expression and deletion analysis revealed that both gtfC and gtfD mediate glycosylation of Pls. Additionally, the recently reported glycosyltransferases SdgA and SdgB are involved in Pls glycosylation. Glycosylation occurs at serine residues in the Pls SD-repeat region and modifying carbohydrates are N-acetylhexosaminyl residues. Functional characterization revealed that Pls can confer increased biofilm formation, which seems to involve two distinct mechanisms. The first mechanism depends on glycosylation of the SD-repeat region by GtfC/GtfD and probably also involves eDNA, while the second seems to be independent of glycosylation as well as eDNA and may involve the centrally located G5 domains. Other previously known Pls properties are not related to the sugar modifications. In conclusion, Pls is a glycoprotein and Pls glycosyl

  5. In vitro comparison of A-56619, A-56620, amifloxacin, ciprofloxacin, enoxacin, norfloxacin, and ofloxacin against methicillin-resistant Staphylococcus aureus.

    PubMed Central

    Smith, S M

    1986-01-01

    Seven quinolone antibiotics were tested against 115 isolates of methicillin-resistant Staphylococcus aureus. The MICs for 90% of the strains tested were 0.5 microgram/ml for A-56619, A-56620, ciprofloxacin, and ofloxacin; 2.0 micrograms/ml for amifloxacin and enoxacin; and 4.0 micrograms/ml for norfloxacin. Killing kinetic studies showed a similar killing rate for all seven antibiotics. PMID:2940966

  6. Staphylococcal Cassette Chromosome mec and Panton-Valentine Leukocidin Characterization of Methicillin-Resistant Staphylococcus aureus Clones▿

    PubMed Central

    Moroney, Shannon M.; Heller, Loree C.; Arbuckle, Jesse; Talavera, Monica; Widen, Ray H.

    2007-01-01

    Staphylococcal cassette chromosome mec (SCCmec) types and Panton-Valentine leukocidin (PVL) gene carriage were compared among suspected community-associated methicillin-resistant Staphylococcus aureus MRSA (CA-MRSA) and health care-associated MRSA (HA-MRSA) isolates. CA-MRSA isolates carried the SCCmec type IV complex, and most were PVL positive. The HA-MRSA isolates carried the SCCmec type II complex and did not harbor the PVL genes. PMID:17192420

  7. Draft Genome Sequence of Methicillin-Resistant Staphylococcus aureus Strain LC33 Isolated from Human Breast Milk.

    PubMed

    de Almeida, Jéssica B; de Carvalho, Suzi P; de Freitas, Leandro M; Guimarães, Ana Marcia S; do Nascimento, Naíla C; Dos Santos, Andrea P; Messick, Joanne B; Timenetsky, Jorge; Marques, Lucas M

    2017-04-13

    Here, we report the draft genome sequence of Staphylococcus aureus strain LC33, isolated from human breast milk in Brazil. This microorganism has been typed as ST1/t127/sccmecV. To our knowledge, this is the first draft genome sequence of a methicillin-resistant S. aureus strain isolated from human breast milk. Copyright © 2017 de Almeida et al.

  8. Draft Genome Sequences of Two Clinical Methicillin-Resistant Staphylococcus aureus Strains Isolated from Healthy Children in Brazil

    PubMed Central

    de Carvalho, Suzi P.; de Almeida, Jéssica B.; de Freitas, Leandro M.; Guimaraes, Ana Marcia S.; do Nascimento, Naíla C.; dos Santos, Andrea P.; Messick, Joanne B.; Timenetsky, Jorge

    2017-01-01

    ABSTRACT We report here the draft genome sequences of two community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains, C18 and C80, isolated from healthy children from day care centers. To our knowledge, these are the first draft genome sequences of CA-MRSA ST398/CC398/SccmecV and CA-MRSA ST5/CC5/SccmecIVa isolated from healthy children in Brazil. PMID:28408675

  9. Draft Genome Sequences of Two Clinical Methicillin-Resistant Staphylococcus aureus Strains Isolated from Healthy Children in Brazil.

    PubMed

    de Carvalho, Suzi P; de Almeida, Jéssica B; de Freitas, Leandro M; Guimaraes, Ana Marcia S; do Nascimento, Naíla C; Dos Santos, Andrea P; Messick, Joanne B; Timenetsky, Jorge; Marques, Lucas M

    2017-04-13

    We report here the draft genome sequences of two community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains, C18 and C80, isolated from healthy children from day care centers. To our knowledge, these are the first draft genome sequences of CA-MRSA ST398/CC398/SccmecV and CA-MRSA ST5/CC5/SccmecIVa isolated from healthy children in Brazil. Copyright © 2017 de Carvalho et al.

  10. Survival of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus spp. for an extended period of transport.

    PubMed

    Robinson, Gwen L; Harris, Anthony D; Morgan, Daniel J; Pineles, Lisa; Belton, Beverly M; Johnson, J Kristie

    2012-07-01

    This study determined the survivability of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) for extended periods of time and temperatures using a standard swab for assessment. Our study showed that transportation in Liquid Amies medium could be performed at room temperature or 4°C for up to 14 days without a decrease in recovery of MRSA or VRE.

  11. 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

  12. Methicillin-Resistant Staphylococcus aureus (MRSA) Infections in the Department of Defense (DOD): Annual Summary Report 2014

    DTIC Science & Technology

    2015-10-01

    NAVY AND MARINE CORPS PUBUC IEAI.TI CINTIR PREVENTION AND PROTECTION START HERE Methicillin-Resistant Staphylococcus aureus IMRSAJ Infections in...Chukwuma Navy and Marine Corps PWiic Heatth Center EpiData Center Department 620 John Paul Jones Circle, Suite 1100 Portsmou1h, VA 23708 Navy and... Marine Corps Pulllic Heatth Center EpiData Center Department 620 John Paul Jones Circle, Suite 1100 Portsmou1h, VA 23708 Approved fa Public Release

  13. 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

  14. Prospective Two-Center Comparison of Three Chromogenic Agars for Methicillin-Resistant Staphylococcus aureus Screening in Hospitalized Patients

    PubMed Central

    Verhulst, Carlo; Nonhoff, Claire; Nagant, Carole; Denis, Olivier; Kluytmans, Jan

    2015-01-01

    Three chromogenic media, chromID MRSA SMART (SMART), chromID MRSA first generation (chromID), and Brilliance MRSA (OX2), were evaluated for methicillin-resistant Staphylococcus aureus (MRSA) screening using 1,220 samples. The sensitivity at 24 h was significantly better with the SMART agar (66.4%) than that with chromID agar (50.5%). Enrichment and incubation until 48 h are still needed for an optimal yield. PMID:26109446

  15. Amplitude-integrated electroencephalography and MRI findings in a case of severe neonatal methicillin-resistant Staphylococcus aureus meningitis

    PubMed Central

    Olischar, Monika; Hunt, Rod W; Daley, Andrew J; Clifford, Vanessa; Tingay, David G

    2010-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) can cause serious infection among hospitalised patients. The emergence of community acquired strains of MRSA (CA-MRSA) increases the potential exposure of newborns. The high incidence of reported meningitis in neonates in large CA-MRSA outbreaks suggests increased virulence in the neonatal population. The authors describe a case of severe meningitis due to MRSA in a previously healthy neonate and include findings from amplitude-integrated electroencephalography (aEEG) and MRI. PMID:22802366

  16. Tertiary amides of Salinomycin: A new group of antibacterial agents against Bacillus anthracis and methicillin-resistant Staphylococcus epidermidis.

    PubMed

    Stefańska, Joanna; Antoszczak, Michał; Stępień, Karolina; Bartoszcze, Michał; Mirski, Tomasz; Huczyński, Adam

    2015-01-01

    For the first time, a series of tertiary amides of polyether antibiotic-Salinomycin have been obtained and screened for their antibacterial activity against different strains of bacteria, including Bacillus anthracis and clinical methicillin-resistant Staphylococcus epidermidis (MRSE). Moreover, biofilm inhibition of MRSE and genotoxicity tests against Bacillus subtilis have been performed. Our studies show that Salinomycin and its some derivatives are active against tested bacteria and exhibited definitely bacteriostatic, not bactericidal activity.

  17. Survival of Methicillin-Resistant Staphylococcus aureus and Vancomycin-Resistant Enterococcus spp. for an Extended Period of Transport

    PubMed Central

    Robinson, Gwen L.; Harris, Anthony D.; Morgan, Daniel J.; Pineles, Lisa; Belton, Beverly M.

    2012-01-01

    This study determined the survivability of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) for extended periods of time and temperatures using a standard swab for assessment. Our study showed that transportation in Liquid Amies medium could be performed at room temperature or 4°C for up to 14 days without a decrease in recovery of MRSA or VRE. PMID:22535993

  18. Potentiating activity of luteolin on membrane permeabilizing agent and ATPase inhibitor against methicillin-resistant Staphylococcus aureus.

    PubMed

    Joung, Dae-Ki; Lee, Young-Seob; Han, Sin-Hee; Lee, Sang-Won; Cha, Seon-Woo; Mun, Su-Hyun; Kong, Ryong; Kang, Ok-Hwa; Song, Ho-Jun; Shin, Dong-Won; Kwon, Dong-Yeul

    2016-01-01

    To investigate the mechanism of antibacterial activity of luteolin (LUT) against methicillin-resistant Staphylococcus aureus (MRSA). The mechanism of anti-MRSA activity of LUT was analyzed by the viability assay in membrane permeabilizing agent, ATPase inhibitors, and peptidoglycan (PGN) derived from Staphylococcus aureus (S. aureus). Also, transmission electron microscopy was used to monitor survival characteristics and changes in S. aureus morphology. Compared to the LUT alone, the optical density of suspensions treated with the combination of 125 μg/mL Tris and 250 μg/mL N,N'-dicyclohexylcarbodiimide were reduced to 60% and 46% of the control, respectively. PGN (15.6 μg/mL) gradually impeded the activity of LUT, and PGN (62.5 μg/mL) completely blocked the activity of LUT on S. aureus. Increased susceptibility to LUT with the Tris-dicyclohexylcarbodiimide combinations is evident in all tested MRSA isolates. The results indicate LUT synergy in increasing cytoplasmic membrane permeability and inhibiting ATPase. S. aureus PGN directly blocks the antibacterial activity of LUT, suggesting the direct binding of LUT with PGN. These findings may be validated for the development of antibacterial agent for low MRSA resistance. Copyright © 2016 Hainan Medical College. Production and hosting by Elsevier B.V. All rights reserved.

  19. Antibiotic susceptibilities and prevalence of Methicillin resistant Staphylococcus aureus (MRSA) isolated from bovine milk in Pakistan.

    PubMed

    Aqib, Amjad Islam; Ijaz, Muhammad; Anjum, Aftab Ahmad; Malik, Muhammad Abdul Rauf; Mehmood, Khalid; Farooqi, Shahid Hussain; Hussain, Kashif

    2017-08-07

    The study was designed to investigate bovine milk for prevalence of an emerging zoonotic pathogen Methicillin resistant Staphylococcus aureus (MRSA), and in-vitro therapeutic response of various antibiotics against MRSA. Nine hundred (900) milk samples were collected (half from cattle and half from buffalo) from private and public farms located in various tehsils of district Faisalabad, using the convenient sampling method. Milk samples were put to biochemical identification of Staphylococcus aureus and later oxacilline disk sensitivity testing for confirmation of MRSA. The MRSA isolates were confirmed by PCR targeting mecA gene in Staphylococcus aureus. The study found 34% prevalence of MRSA in overall bovine milk from district Faisalabad with 30% and 38% prevalence in cattle and buffalo, respectively. Tehsil Samundari presented comparatively higher MRSA prevalence followed by tehsil Jaranwala and tehsil Faisalabad. However, there was non-significant difference of MRSA prevalence between cattle and buffalo, and among different tehsils. All assumed risk factors except specie were significantly associated with mastitis spread. The in-vitro drug trial against MRSA from buffalo milk presented 100% efficacy of Ciprofloxcin, Moxifloxacin, Linezolid, and Trimethoprim plus Sulphamethoxazole combination, followed by Gentamicin and Levofloxacin presenting 90%, and Amikacin becoming 80% efficacious against MRSA from buffalo milk. The MRSA isolates of cattle milk presented similar pattern with some variations of higher susceptibility against Oxytetracycline, and Fusidic acid. The conclusion of the study states uniform prevalence of MRSA in cattle and buffalo milk in study area having assumed risk factors positively associated with disease spread, while Ciprofloxcin, Moxifloxacin, Linezolid, and Trimethoprim plus Sulphamethoxazole drugs showed the highest efficacy to combat this pathogen. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Short communication: Prevalence of Staphylococcus aureus and methicillin-resistant S. aureus in bulk tank milk from dairy goat farms in Northern Italy.

    PubMed

    Cortimiglia, C; Bianchini, V; Franco, A; Caprioli, A; Battisti, A; Colombo, L; Stradiotto, K; Vezzoli, F; Luini, M

    2015-04-01

    Staphylococcus aureus is regarded as a leading cause of mastitis in goats. However, few data are available on the presence of methicillin-resistant S. aureus (MRSA) in this species. The aim of this study was to assess the prevalence of S. aureus and MRSA in bulk tank milk samples from dairy goat farms in Northern Italy. Eighty-five out of 197 samples (43.1%) tested positive for S. aureus with counts ranging from 10 to more than 1.5 × 10(4) cfu/mL. The MRSA was screened by both direct plating followed by a disk diffusion test to evaluate methicillin resistance and a selective enrichment method. Methicillin-resistance was confirmed by mecA-specific PCR. Methicillin-resistant S. aureus was identified in 4 samples (2.0%) and multilocus sequence typing (MLST) showed the presence of livestock-associated MRSA belonging to lineages ST398 (n = 3) and ST1 (n = 1). In one case we demonstrated that the same MRSA strain was able to persist over time on the farm, being isolated from both bulk tank milk and the udder of 3 goats 1 yr after the first isolation. The high prevalence of S. aureus-positive herds detected in this study and the presence of MRSA strains belonging to livestock-associated genotypes is of concern, and represents a novel finding in the Italian dairy goat production system. The application of stringent measures for the control of S. aureus mastitis at the farm level seems appropriate to reduce the economic losses, and to minimize the risk of foodborne illness and the transmission of MRSA to humans by occupational exposure.

  1. Topological pattern for the search of new active drugs against methicillin resistant Staphylococcus aureus.

    PubMed

    Bueso-Bordils, Jose I; Perez-Gracia, Maria T; Suay-Garcia, Beatriz; Duart, Maria J; Martin Algarra, Rafael V; Lahuerta Zamora, Luis; Anton-Fos, Gerardo M; Aleman Lopez, Pedro A

    2017-09-29

    Molecular topology was used to develop a mathematical model capable of classifying compounds according to antimicrobial activity against methicillin resistant Staphylococcus aureus (MRSA). Topological indices were used as structural descriptors and their relation to antimicrobial activity was determined by using linear discriminant analysis. This topological model establishes new structure activity relationships which show that the presence of cyclopropyl, chlorine and ramification pairs at a distance of two bonds favor this activity, while the presence of tertiary amines decreases it. This model was applied to a combinatorial library of a thousand and one 6-fluoroquinolones, from which 117 theoretical active molecules were obtained. The compound 10 and five new quinolones were tested against MRSA. They all showed some activity against MRSA, although compounds 6, 8 and 9 showed anti-MRSA activity similar to ciprofloxacin. This model was also applied to 263 theoretical antibacterial agents described by us in a previous work, from which 34 were predicted as theoretically active. Anti-MRSA activity was found bibliographically in 9 of them (ensuring at least 26% of success), and from the rest, 3 compounds were randomly chosen and tested, finding mitomycin C to be more active than ciprofloxacin. The results demonstrate the utility of the molecular topology approaches for identifying new drugs active against MRSA. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. Upregulated effects of miR-7 in methicillin-resistant Staphylococcus aureus

    PubMed Central

    Zhang, Hong; Li, Haiqing; Liu, Yan; Li, Qingyan; Bi, Yufang; Fang, Guiqing

    2016-01-01

    The aim of the study was to investigate the characteristic function of the upregulated effects of miR-7 in methicillin-resistant Staphylococcus aureus (MRSA). After separating the MRSA in clinic, the expression of miR-7 mRNA was tested by reverse transcription polymerase chain reaction. The overexpression, inhibition of miR-7, and control group were established by plasmid in vitro. Following transfection of the bacterial strain, the effect of β-lactam antibiotics in minimum inhibitory concentration (MIC) was observed using the microporous dilution method, and antibacterial effects in vitro were observed using the dynamic growth curve method. The expression of miR-7 in sensitive MRSA was upregulated distinctly, with significant difference (P<0.05). MIC and the number of bacteria in the miR-7 overexpression group significantly increased while the inhibition group decreased prominently, with significant difference (P<0.05). The control and null plasmid groups revealed no significant difference. In conclusion, miR-7 upregulated the antimicrobial activity of MRSA, and the intervention of its expression may become a possible antibacterial target. PMID:28101153

  3. 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

  4. 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.

  5. 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.

  6. Susceptibility profile of methicillin-resistant Staphylococcus aureus to linezolid in clinical isolates

    PubMed Central

    Shariq, Ali; Tanvir, Syed Bilal; Zaman, Atif; Khan, Salman; Anis, Armeena; Khan, Misha Aftab; Ahmed, Sumaira

    2017-01-01

    Objective: To determine the resistance and sensitivity pattern of methicillin-resistant Staphylococcus aureus (MRSA) isolates to linezolid (LZD) along with its prevalence in a tertiary care hospital of Karachi, Pakistan. Materials and Methods: A cross-sectional study was carried out. This study lasted for about 1 year. Prevalence and sensitivity of LZD, vancomycin, and oxacillin was tested against isolates of MRSA. Results: Out of total 369 specimens 165 were found to be MRSA making the prevalence in our study 44.7%. All of the isolates which were tested positive for MRSA were susceptible to LZD and no resistance was noted when compared with previous studies performed in Europe and USA. Conclusion: Stringent implementation of infection control measures along with screening for resistance in patients on prolonged LZD therapy or who previously went under LZD therapy should be performed, coupled with judicious usage of the aforementioned antibiotic should be undertaken, as sufficient data is not available at this point for the clinical spectrum of LZD resistant S. aureus, antimicrobial resistance. PMID:28293153

  7. Methicillin-resistant Staphylococcus aureus in public transportation vehicles (buses): another piece to the epidemiologic puzzle.

    PubMed

    Lutz, Jonathan K; van Balen, Joany; Crawford, John Mac; Wilkins, John R; Lee, Jiyoung; Nava-Hoet, Rocio C; Hoet, Armando E

    2014-12-01

    Little is known about the occurrence and epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in public transportation in the United States. This research sought to determine the background prevalence and phenotypic and genotypic characteristics of MRSA strains circulating on buses from a large, metropolitan transportation agency. Electrostatic wipes were used to collect 237 surface samples from 40 buses randomly selected from July-October 2010. Six samples were collected from each bus immediately postservice and before any cleaning and disinfection. Positive isolates were analyzed for antibiotic resistance, staphylococcal cassette chromosome mec (SCCmec) type, and pulsed-field gel electrophoresis; and potential epidemiologic factors were examined. Of the buses, 68% (27/40) were contaminated with S aureus, and 63% (25/40) were contaminated with MRSA. Seats and seat rails were the surfaces most frequently contaminated, followed by the back door and stanchions. Most (62.9%) of the MRSA isolates were classified as community-associated MRSA clones (SCCmec type IV), and 22.9% were health care-associated MRSA clones (SCCmec type II). Of the MRSA strains, 65% (5/20) were multidrug resistant. MRSA was frequently isolated from commonly touched surfaces in buses serving both hospital and community routes. Phenotypic and genotypic analysis demonstrated that buses may be effective mixing vessels for MRSA strains of both community and health care-associated origin. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  8. Disease Burden, Characteristics, and Outcomes of Methicillin-Resistant Staphylococcus aureus Bloodstream Infection in Hong Kong.

    PubMed

    You, Joyce H S; Choi, Kin-Wing; Wong, Tin-Yau; Ip, Margaret; Ming, Wai-Kit; Wong, Rity Yee-Kwan; Chan, Sze-Ngai; Tse, Hoi-Tung; Chau, Carrie T S; Lee, Nelson L S

    2017-07-01

    We aimed to describe disease burden, characteristics, and outcomes of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) in Hong Kong. A retrospective, observational study was conducted in 26 Hong Kong public hospitals between January 2010 and December 2012. The primary outcome measures were 30-day mortality rate and infection-related hospital cost. Of 1133 patients reviewed, 727 (64.17%) were male, 1075 (94.88%) had health care-associated community-onset and 44 (3.88%) had hospital-onset MRSA infection. The mean age of patients was 76 (SD = 15) years, including 172 (15.18%) aged 20 to 59 years and 961 (84.8%) aged ≥60 years. The annual incidence rates in age groups of 20 to 59 years and ≥60 years were 0.96 to 1.148 per 100 000 and 22.7 to 24.8 per 100 000, respectively. The 30-day mortality was 367 (32.39%). Older patients (>79 years), chronic lung disease, and prior hospitalization were associated with increased mortality. The mean cost was US$10 565 (SD = 11 649; US$1 = HK$7.8). MRSA BSI was a significant burden in Hong Kong.

  9. 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

  10. Prevalence of methicillin resistant Staphylococcus aureus [MRSA] colonization or carriage among health-care workers.

    PubMed

    Pathare, Nirmal A; Asogan, Harshini; Tejani, Sara; Al Mahruqi, Gaitha; Al Fakhri, Salma; Zafarulla, Roshna; Pathare, Anil V

    2016-01-01

    In Oman, the prevalence of health care associated methicillin resistant Staphylococcus aureus [HA-MRSA] is unknown. Therefore, to estimate the prevalence of HA-MRSA, we collected nasal swabs and swabs from cell phones on sterile polyester swabs and immediately inoculated on the mannitol salt agar containing oxacillin from medical students and hospital health care providers. Antibiotic susceptibility testing of the isolates was then performed using the Kirby Bauer's disc diffusion method. Additionally, a brief survey questionnaire was used to acquire demographic data. Amongst the 311 participants enrolled, nasal colonization with HA-MRSA was found in 47 individuals (15.1%, 95% confidence interval [CI]=11.1%, 19.1%). HA-MRSA was also isolated from the cell phone surfaces in 28 participants (9.0%, 95% CI=8.6%, 9.3%). 5 participants (1.6%) showed positive results both from their nasal swabs and from their cell phones. Antibiotic resistance to erythromycin [48%] and clindamycin [29%] was relatively high. 9.3% HA-MRSA isolates were vancomycin resistant [6.6% nasal carriage]. There was no statistically significant correlation between HA-MRSA isolates and the demographic characteristics or the risk factors namely gender, underlying co-morbidities like diabetes, hypertension, skin/soft tissue infections, skin ulcers/wounds, recent exposure to antibiotics, or hospital visits (p>0.05, Chi-square test). Copyright © 2015 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

  11. Synergistic effects of the combination of galangin with gentamicin against methicillin-resistant Staphylococcus aureus.

    PubMed

    Lee, Young-Seob; Kang, Ok-Hwa; Choi, Jang-Gi; Oh, You-Chang; Chae, Hee-Sung; Kim, Jong Hak; Park, Hyun; Sohn, Dong Hwan; Wang, Zheng-Tao; Kwon, Dong-Yeul

    2008-06-01

    The antimicrobial killing activity toward methicillin-resistant Staphylococcus aureus (MRSA) has been a serious emerging global issue. New effective antimicrobials and/or new approaches to settle this issue are urgently needed. The oriental herb, Alpinia officinarum, has been used in Korea for several hundreds of years to treat various infectious diseases. As it is well known, one of the active constituents of Alpinia officinarum is galangin. Against the 17 strains, the minimum inhibitory concentrations (MICs) of galangin (GAL) were in the range of 62.5 ~ 125 microg/ml, and the MICs of gentamicin (GEN) ranged from 1.9 microg/ml to 2,000 microg/ml. The fractional inhibitory concentrations (FICs) of GAL, in combination with GEN, against 3 test strains were 0.4, 3.9, and 250 microg/ml, and were all 15.62 microg/ml in GEN. The FIC index showed marked synergism in the value range of 0.19 to 0.25. By determining time-kill curves, also confirmed the low synergism of the GAL and GEN combination against 4 h, 8 h, 12 h, and 24 h cultured MRSA. The time-kill study results indicated a low synergistic effect against 3 test strains. Thus, the mixture of GAL and GEN could lead to the development of new combination antibiotics against MRSA infection.

  12. Methicillin-resistant Staphylococcus aureus (MRSA) on the skin of long-term hospitalised horses.

    PubMed

    Van den Eede, A; Hermans, K; Van den Abeele, A; Floré, K; Dewulf, J; Vanderhaeghen, W; Crombé, F; Butaye, P; Gasthuys, F; Haesebrouck, F; Martens, A

    2012-08-01

    Given the significance of methicillin-resistant Staphylococcus aureus (MRSA) infections for both horses and staff in equine veterinary hospitals, protocols are required to minimise the risk of nosocomial transmission, including the screening of the skin and nasal chambers of equine patients for evidence of infection. The objective of this study was to clarify the potential existence and extent of MRSA on the skin of horses requiring long-term hospitalisation (≥ 6 months). Thirty such horses were sampled at eight different locations on their skin and from their nasal chambers. MRSA was isolated from 12 animals (40%), with all sample sites testing positive on at least one occasion. Organisms were most frequently detected in the nasal chambers (relative sensitivity, 83.3%; 34.5% positive horses; isolation rate 33.3%). Skin presence was found in 30% of animals with the highest isolation rates found at the carpus (16.7%), neck, withers and croup (13.3% each). To achieve a relative screening sensitivity of >90%, at least one skin site was required in addition to nasal sampling. This evidence of skin as well as nasal reservoirs of MRSA in long-term hospitalised horses should facilitate the design of effective screening and containment protocols.

  13. 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

  14. 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

  15. Comparative Genomics of Canadian Epidemic Lineages of Methicillin-Resistant Staphylococcus aureus▿ †

    PubMed Central

    Christianson, Sara; Golding, George R.; Campbell, Jennifer; Mulvey, Michael R.

    2007-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen that has disseminated throughout Canadian hospitals and communities. Pulsed-field gel electrophoresis of over 9,300 MRSA isolates obtained from the Canadian Nosocomial Infection Surveillance Program has identified 10 epidemic strain types in Canada (CMRSA1 to CMRSA10). In an attempt to determine specific genetic factors that have contributed to their high prevalence in community and/or hospital settings, the genomic content of representative isolates for each of the 10 Canadian epidemic types was compared using comparative genomic hybridizations. Comparison of the community-associated Canadian epidemic isolates (CMRSA7 and CMRSA10) with the hospital-associated Canadian epidemic isolates revealed one open reading frame (ORF) (SACOL0046) encoding a putative protein belonging to a metallo-beta-lactamase family, which was present only in the community-associated Canadian epidemic isolates. A more restricted comparison involving only the most common hospital-associated Canadian epidemic isolates (CMRSA1 and CMRSA2) with the community-associated Canadian epidemic isolates did reveal additional factors that might be contributing to their prevalence in the community and hospital settings, which included ORFs encoding potential virulence factors involved in capsular biosynthesis, serine proteases, epidermin, adhesion factors, regulatory functions, leukotoxins, and exotoxins. PMID:17428941

  16. 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

  17. Ceftaroline: A New Cephalosporin with Activity against Methicillin-Resistant Staphylococcus aureus (MRSA)

    PubMed Central

    Duplessis, Christopher; Crum-Cianflone, Nancy F.

    2011-01-01

    Microbial resistance has reached alarming levels, threatening to outpace the ability to counter with more potent antimicrobial agents. In particular, methicillin-resistant Staphylococcus aureus (MRSA) has become a leading cause of skin and soft-tissue infections and PVL-positive strains have been associated with necrotizing pneumonia. Increasing reports of growing resistance to glycopeptides have been noted, further limiting the efficacy of standard antibiotics, such as vancomycin. Ceftaroline is a novel fifth-generation cephalosporin, which exhibits broad-spectrum activity against Gram-positive bacteria, including MRSA and extensively-resistant strains, such as vancomycin-intermediate S. aureus (VISA), heteroresistant VISA (hVISA), and vancomycin-resistant S. aureus (VRSA). In addition to being an exciting new agent in the anti-MRSA armamentarium, ceftaroline provides efficacy against many respiratory pathogens including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Ceftaroline (600 mg intravenously every 12 hours) has been shown effective in phase III studies in the treatment of complicated skin and soft tissue infections and community-acquired pneumonia. To date, this unique antibiotic exhibits a low propensity for inducing resistance and has a good safety profile, although further post-marketing data and clinical experience are needed. In summary, ceftaroline provides an additional option for the management of complex multidrug resistant infections, including MRSA. PMID:21785568

  18. Interactions of Methicillin Resistant Staphylococcus aureus USA300 and Pseudomonas aeruginosa in Polymicrobial Wound Infection

    PubMed Central

    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. PMID:23451098

  19. 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

  20. 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.

  1. Rapid screening for carriage of methicillin-resistant Staphylococcus aureus by PCR and associated costs.

    PubMed

    Bühlmann, Manuela; Bögli-Stuber, Katja; Droz, Sara; Mühlemann, Kathrin

    2008-07-01

    PCR tests for the rapid and valid detection of methicillin-resistant Staphylococcus aureus (MRSA) are now available. We evaluated the costs associated with contact screening for MRSA carriage in a tertiary-care hospital with low MRSA endemicity. Between 1 October 2005 and 28 February 2006, 232 patients were screened during 258 screening episodes (644 samples) for MRSA carriage by GenoType MRSA Direct (Hain Lifescience GmbH, Nehren, Germany). Conventional culture confirmed all PCR results. According to in-house algorithms, 34 of 258 screening episodes (14.7%) would have qualified for preemptive contact isolation, but such isolation was not done upon negative PCR results. MRSA carriage was detected in 4 (1.5%) of 258 screening episodes (i.e., in four patients), of which none qualified for preemptive contact isolation. The use of PCR for all 258 screening episodes added costs (in Swiss francs [CHF]) of CHF 104,328.00 and saved CHF 38,528.00 (for preemptive isolation). The restriction of PCR screening to the 34 episodes that qualified for preemptive contact isolation and screening all others by culture would have lowered costs for PCR to only CHF 11,988.00, a savings of CHF 38,528.00. Therefore, PCR tests are valuable for the rapid detection of MRSA carriers, but high costs require the careful evaluation of their use. In patient populations with low MRSA endemicity, the broad use of PCR probably is not cost-effective.

  2. 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

  3. Tricuspid and mitral endocarditis due to methicillin-resistant Staphylococcus aureus exhibiting vancomycin-creep phenomenon.

    PubMed

    Sundaragiri, Pranathi Rao; Vallabhajosyula, Saraschandra; Haddad, Toufik Mahfood; Esterbrooks, Dennis J

    2015-11-03

    Right-sided infective endocarditis (RIE) is commonly due to Staphylococcus aureus and often involves the tricuspid valve (TV). A 31-year-old man with prior intravenous drug use presented with substernal pain, cough, dyspnoea and fever. Examination revealed a febrile, tachycardic male with peripheral infective endocarditis stigmata and right-heart failure. Laboratory parameters demonstrated leucocytosis, lactic acidosis and methicillin-resistant S. aureus (MRSA) bacteraemia. Echocardiography demonstrated multiple TV echodensities and chest imaging confirmed septic emboli. The MRSA species demonstrated 'vancomycin-creep', necessitating therapy with daptomycin and ceftaroline. Owing to persistent bacteraemia and septic shock, the patient underwent TV surgery, but continued to have a poor postoperative course with subsequent death. Indications for surgical therapy of RIE are limited to the European guidelines and most data are extrapolated from left-heart disease. MRSA exhibiting vancomycin-creep portends a poorer prognosis and requires aggressive therapy. We advocate the use of ceftaroline salvage therapy with daptomycin, pending further trials. 2015 BMJ Publishing Group Ltd.

  4. Necrotizing fasciitis caused by Staphylococcus aureus: the emergence of methicillin-resistant strains.

    PubMed

    Cheng, Nai-Chen; Wang, Jann-Tay; Chang, Shan-Chwen; Tai, Hao-Chih; Tang, Yueh-Bih

    2011-12-01

    Staphylococcus aureus is an uncommon causative agent of monomicrobial necrotizing fasciitis, but we have noted several cases over the years. The patients treated for necrotizing fasciitis between January 1998 and December 2008 in our institution were identified, and their medical records were reviewed. Of 105 necrotizing fasciitis cases during the study period, 18 were caused by monomicrobial S. aureus infection (17%). The median age was 62 years (range, 12-81 years). Among this cohort, 10 patients had coexisting medical conditions or risk factors, including diabetes and hypertension. Lower limbs and upper limbs are the most commonly involved sites. Among the bacterial isolates from these cases, 8 were methicillin-sensitive S. aureus (MSSA) and 10 were methicillin-resistant S. aureus (MRSA). One patient died in the MSSA group, and 5 patients died in the MRSA group. The mortality rate and other clinical characteristics were not significantly different between the 2 groups. However, all MRSA necrotizing fasciitis developed after the year 2000, and it was significantly different from MSSA necrotizing fasciitis that predominantly took place before the year 2000. In conclusion, S. aureus is an important pathogen of monomicrobial necrotizing fasciitis, and MRSA has emerged as the predominant causative agent in recent years. Therefore, MRSA-directed antibiotic therapy should be considered when treating patients suspected with necrotizing fasciitis in endemic areas.

  5. Responses in the expression of extracellular proteins in methicillin-resistant Staphylococcus aureus treated with rhodomyrtone.

    PubMed

    Visutthi, Monton; Srimanote, Potjanee; Voravuthikunchai, Supayang Piyawan

    2011-12-01

    Rhodomyrtone from a medicinal plant species, Rhodomyrtus tomentosa, is a challenged effective agent against Gram-positive bacteria, especially methicillin-resistant Staphylococcus aureus (MRSA). The present study was undertaken to provide insight into MRSA extracellular protein expression following rhodomyrtone treatment. Secreteomic approach was performed on a representative clinical MRSA isolate exposing to subinhibitory concentration rhodomyrtone (0.174 μg/ml). The identified extracellular proteins of a response of MRSA to rhodomyrtone treated condition were both suppressed and overexpressed. Staphylococcal antigenic proteins, immunodominant antigen A (IsaA) and staphylococcal secretory antigen (SsaA) involved in cell wall hydrolysis were downregulated after the treatment. The results suggested that rhodomyrtone may interfere with WalK/WalR (YycG/YycF) system. Other enzymes such as lipase precursor and another lipase, glycerophosphoryl diester phosphodiesterase, were absent. In contrast, cytoplasmic proteins such as SpoVG and glycerol phosphate lipoteichoic acid synthase, and ribosomal proteins were found in the treated sample. Appearance of several cytoplasmic proteins in the treated culture supernatant revealed that the bacterial cell wall biosynthesis was disturbed. This finding provides a proteomic mapping of extracellular proteins after rhodomytone treatment. Extensive investigation is required for this natural compound as it has a great potency as an alternative anti-MRSA drug.

  6. Novel and uncommon antimicrobial resistance genes in livestock-associated methicillin-resistant Staphylococcus aureus.

    PubMed

    Kadlec, K; Fessler, A T; Hauschild, T; Schwarz, S

    2012-08-01

    Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) isolates have been the subject of numerous studies during recent years. The characterization of such isolates has usually also included the determination of their resistance phenotypes and associated resistance genotypes. Analysis of the resistance genes present in LA-MRSA isolates has revealed a number of genes commonly found in S. aureus and coagulase-negative staphylococci of humans and animals. In addition, novel resistance genes and/or resistance genes that have been rarely detected in staphylococci so far have been encountered. These include the phenicol exporter gene fexA, the multiresistance gene cfr, the tetracycline resistance gene tet(L), the trimethoprim resistance gene dfrK, the macrolide-lincosamide-streptogramin B resistance gene erm(T), the lincosamide-streptogramin A-pleuromutilin resistance genes vga(C) and vga(E), and the apramycin resistance gene apmA. Most of these genes were located on multiresistance plasmids in LA-MRSA. The co-localization of these resistance genes with other resistance genes enables their co-selection and persistence. LA-MRSA can therefore act as a donor and a recipient of antimicrobial resistance genes within the Gram-positive gene pool. © 2012 The Authors. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.

  7. A novel molecular pattern for methicillin-resistant Staphylococcus aureus in Milwaukee, WI clinical isolates.

    PubMed

    Burlage, Robert S; Mahdi, Nader

    2009-03-01

    Methicillin-resistant Staphylococcus aureus is a significant problem in healthcare settings around the world. To effectively track different strains, we used a number of genetic procedures. In this study, 252 clinical isolates from the Milwaukee, WI, area were analyzed by the multiplex polymerase chain reaction (PCR) method to determine which of the described types were present. Most strains were categorized into one of the known groups, although types III and IIIA strains were not found. An unusual variant was found in 17% of the samples. This variant (v1) contains an 800-base pair amplimer that was created from a unique configuration of 2 primers from different sets in the multiplex PCR procedure. Although superficially similar to a type I pattern, sequencing of the amplimer demonstrated that it is identical to a sequence from the USA300 strain, a type IV strain. It is suggested that this variant may have resulted from acquisition of an IS431 element near the dcs region. There is potential for misidentification of strains because of slight genetic alterations such as this one. Statistical analysis using a chi(2) contingency table demonstrated that amoxicillin/clavulanic acid resistance was significantly lower in types I and IA when compared with the other types, whereas erythromycin resistance was significantly lower in type I when compared with other types. However, there was not a significant difference for any of the new variants.

  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. Methicillin-Resistant Staphylococcus aureus Keratitis after Descemet's Stripping Automated Endothelial Keratoplasty

    PubMed Central

    Miyamoto, Tatsuro; Eguchi, Hiroshi; Tserennadmid, Ehkhmaa; Mitamura-Aizawa, Sayaka; Hotta, Fumika; Mitamura, Yoshinori

    2013-01-01

    Purpose We report a case of methicillin-resistant Staphylococcus aureus (MRSA) keratitis after Descemet's stripping automated endothelial keratoplasty (DSAEK). Case Report An 87-year-old woman who had undergone a DSAEK 4 months previously was referred to Tokushima University Hospital with a diagnosis of infectious keratitis after DSAEK. A white abscess and infiltration in the inferior cornea of the right eye were observed. We started an empiric therapy using topical levofloxacin and chloramphenicol on the basis of the microscopic findings of the corneal scraping concurrently with cultivation of the cornea. Results A strain of MRSA was isolated from the corneal sample. Although the strain was susceptible to chloramphenicol, it was resistant to quinolone. The keratitis improved rapidly due to empiric therapy, and topical steroids could be resumed 6 days after initiation of the empiric therapy. Conclusions To our knowledge, this is the first case of MRSA keratitis, and the second case of bacterial keratitis, after DSAEK. MRSA keratitis can occur following uneventful DSAEK. The empiric therapy on the basis of results from a light microscopic examination of a Gram-stained corneal scraping and restarting topical steroids in the early stages of medication contributed to the good clinical course of this case. PMID:24348415

  10. Enteral vancomycin and probiotic use for methicillin-resistant Staphylococcus aureus antibiotic-associated diarrhoea

    PubMed Central

    Sizemore, Elizabeth Nicole; Rivas, Kenya Maria; Valdes, Jose; Caballero, Joshua

    2012-01-01

    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. PMID:22847566

  11. Methicillin-resistant Staphylococcus aureus from Northwest Marine and Fresh Water Recreational Beaches

    PubMed Central

    Levin-Edens, Emily; Soge, Olusegun O.; No, David; Stiffarm, Amy; Meschke, J. Scott; Roberts, Marilyn C.

    2011-01-01

    The aim of the study was to determine the spatial distribution of methicillin-resistant Staphylococcus aureus [MRSA] at two marine and one fresh water recreational beaches in the Seattle area. Fifty-six marine water, 144 fresh water, and 96 sand samples were collected from June through August 2010. Isolates were biochemically verified as MRSA. Staphylococcal cassette chromosome mec (SCCmec) typing, multilocus sequence typing [MLST], pulse field gel electrophoresis [PFGE] and the presence of other antibiotic resistance genes were determined. Twenty-two fresh water [15.3%; n = 144], one dry sand [1.9%; n = 53], six wet sand [14%; n = 43], and 2 marine water samples [3.6%; n = 56] were MRSA positive. Of the 27 fresh water stream sites sampled multiple times, 37% of the sites were positive for MRSA and/or S. aureus ≥ 2 times. Twenty-one (67.7%) of 31 MRSA were SCCmec type IV, fifteen (48.4%) of the isolates had MLST types not previously associated with humans, and 29 (93.5%) of the isolates carried other antibiotic resistance genes. This study is the first to report and characterize repeated MRSA positive samples from fresh water drainages and creeks surrounding popular recreational beaches. PMID:22092827

  12. Treatment of experimental osteomyelitis by methicillin resistant Staphylococcus aureus with bone cement system releasing grepafloxacin.

    PubMed

    Efstathopoulos, Nicolas; Giamarellos-Bourboulis, Evangellos; Kanellakopoulou, Kyriaki; Lazarettos, Ioannis; Giannoudis, Peter; Frangia, Konstantina; Magnissalis, Evangellos; Papadaki, Maria; Nikolaou, Vassilios S

    2008-12-01

    The authors examined the effectiveness of the local anti-microbial treatment on methicillin resistant Staphylococcus aureus (MRSA) experimental osteomyelitis. Thirty-six rabbits with chronic MRSA osteomyelitis of the right femur were treated with local grepafloxacin delivery system prepared by a mixture of acrylic bone cement (polymethyl methacrylate, PMMA) plus 4% grepafloxacin. Osteomyelitis was induced by inoculating MRSA (100 microl of cultured bacteria; 10(7)) and the local insertion of a needle, serving as a foreign body, at the upper third of the femur. The course of the infection was followed by clinical, radiographic and microbiological examination. In the third week, all animals were re-operated, needles were removed, and antibiotic containing acrylic cement was implanted. Thereafter, one control and five treated animals were sacrificed per week, within 6 weeks. Osteomyelitis was found in all rabbits. In vitro grepafloxacin levels remained high throughout the 6 weeks of the experiment. Histologically tissue reaction against the cement was not observed. Osteomyelitis lesions and bone structure were progressively repaired after cement implantation. Biomechanical analysis showed no significant influence on the mechanical properties of acrylic cement due to grepafloxacin. The above mixture could prove to be an important supplementary method for the treatment of bone infections. Such a system could replace the use of gentamycin PMMA beads in the treatment of patients with chronic osteomyelitis due to MRSA. Furthermore, the proposed method could be used as a spacer after removal septic loosened prostheses in combination with systemic administration of antibiotics.

  13. 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.

  14. Methicillin-resistant Staphylococcus aureus and Vancomycin-resistant Enterococci in Rural Communities, Western United States

    PubMed Central

    Searle, Katy; Stoddard, Gregory; Samore, Matthew H.

    2005-01-01

    The impact and prevalence of antimicrobial drug resistance in rural community healthcare settings is uncertain. Prospective surveillance in 51 rural hospitals in Idaho and Utah examined the epidemiologic features of clinical cases of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Thirty-two cases of VRE were reported; for 6, the patient had no prior healthcare exposure or coexisting condition. Among the 724 MRSA cases available for evaluation, 405 (56%) were healthcare-associated (HA-MRSA), and 319 (44%) were community-associated (CA-MRSA). The characteristics of HA-MRSA and CA-MRSA patients with coexisting factors were similar, which suggests community transmission of healthcare strains. CA-MRSA cases without coexisting factors, however, demonstrated features previously reported for community strains. MRSA infections were substantially more frequent than VRE in rural communities in the western United States. Based on epidemiologic criteria, a large proportion of MRSA cases were community-associated. CA-MRSA rates were predictive of institutional MRSA rates. PMID:15963285

  15. Methicillin-resistant Staphylococcus aureus in tertiary care institutions on the Canadian prairies 1990-1992.

    PubMed

    Embil, J; Ramotar, K; Romance, L; Alfa, M; Conly, J; Cronk, S; Taylor, G; Sutherland, B; Louie, T; Henderson, E

    1994-10-01

    To review experience with methicillin-resistant Staphylococcus aureus (MRSA) in tertiary acute-care teaching hospitals on the Canadian prairies. Retrospective review for a 36-month period, 1990 through 1992. Five tertiary acute-care teaching hospitals in three Canadian prairie provinces. MRSA isolates and susceptibility were identified through the clinical microbiology laboratory at each institution. For each patient, data collected included duration of institutional residence prior to isolation, patient ethnic background, age, sex, and antimicrobial susceptibility. Epidemiologic typing of strains used restriction fragment length polymorphism analysis by pulsed-field gel electrophoresis. Two hundred fifty-nine MRSA isolates were identified in 135 patients during the 36 months, with substantial institutional variation in number of isolates. No consistent increase in yearly numbers of isolates was apparent. Patients usually had MRSA identified at admission (62%); only one of five centers had the majority of isolates acquired nosocomially. Patients with MRSA present at admission were more frequently of aboriginal (First Nations) ethnicity (62% compared with 14% of nosocomial; P < 0.001). Pulsed-field gel electrophoresis of 167 isolates from 135 patients revealed 46 different strains with little interprovincial or interinstitutional identity of strains. MRSA isolated in patients in tertiary care institutions in these three Canadian provinces usually is acquired prior to admission. A disproportionate number of isolates are identified in aboriginal Canadians. Epidemiologic typing was consistent with a polyclonal origin of MRSA in this geographic area.

  16. Molecular characterization of methicillin-resistant Staphylococcus aureus isolates in Algeria.

    PubMed

    Ouchenane, Z; Smati, F; Rolain, J-M; Raoult, D

    2011-12-01

    The epidemiology of Staphylococcus aureus has changed radically since 1999, in particular, methicillin-resistant S. aureus (MRSA), originally restricted to hospital, has emerged as a significant pathogen in the community, and true community-acquired MRSA (CA-MRSA) infections have been reported in patients with no clear risk factors. CA-MRSA strains frequently produce Panton-Valentine leukocidin (PVL). The objectives of this study were: (i) to monitor the prevalence of PVL and toxic shock syndrome toxin-1 (TSST-1) isolates MRSA; (ii) to identify the staphylococcal cassette chromosome (SCCmec) types of MRSA isolates. Sixty-four isolates, collected between 2005 and 2007 in Didouche Mourad hospital of Algeria. The isolates were identified by conventional methods. The antibiotic susceptibility of the isolates was performed using the disk diffusion method and automat Vitek2. The presence of gene mecA, the genes encoding SCCmec type, PVL and TSST-1 toxins were investigated by real-time PCR. All strains were gene mecA positives, 32 (50%) harboured SCCmec IV type, 28 (43.75%) harboured SCCmec V type. 19 (29.68%) have been identified positive for the leukocidin toxin (PVL), they harboured SCCmec type IV. The virulence factor TSST-1 was not present among these isolates. These results show a high prevalence of PVL-positive H-MRSA in our wards. Copyright © 2010. Published by Elsevier SAS.

  17. Real-time optical detection of methicillin-resistant Staphylococcus aureus using lytic phage probes.

    PubMed

    Guntupalli, Rajesh; Sorokulova, Iryna; Krumnow, April; Pustovyy, Oleg; Olsen, Eric; Vodyanoy, Vitaly

    2008-09-15

    Staphylococcus aureus (S. aureus)-specific bacteriophage was used as a probe for detection of methicillin-resistant S. aureus (MRSA) in aqueous solution using a novel optical method. Biorecognition phage monolayers transferred to glass substrates using Langmuir-Blodgett (LB) technique were exposed individually to MRSA in solution at logarithmic concentrations ranging from 10(6) to 10(9)cfu/ml, and observed for real-time binding using a CytoViva optical light microscope system. Results indicate that LB monolayers possessed high levels of elasticity (K), measuring 22 and 29 mN/m for 10(9) and 10(11)pfu/ml phage concentrations, respectively. Near-instantaneous MRSA-phage binding produced 33+/-5%, 10+/-1%, 1.1+/-0.1%, and 0.09+/-0.01% coverage of the substrate that directly correlated to a decrease in MRSA concentrations of 10(9), 10(8), 10(7), and 10(6)cfu/ml. The exclusive selectivity of phage monolayers was verified with Salmonella enterica subsp. enterica serovar typhimurium (S. typhimurium) and Bacillus subtilis.

  18. Antibacterial effect of essential oils from two medicinal plants against Methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Tohidpour, A; Sattari, M; Omidbaigi, R; Yadegar, A; Nazemi, J

    2010-02-01

    Antimicrobial properties of plants essential oils (EOs) have been investigated through several observations and clinical studies which purpose them as potential tools to overcome the microbial drug resistance problem. The aim of this research is to study the antibacterial effect of two traditional plants essential oils, Thymus vulgaris and Eucalyptus globulus against clinical isolates of Methicillin resistant Staphylococcus aureus (MRSA) and other standard bacterial strains through disk diffusion and agar dilution methods. Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GC/MS) analysis examined the chemical composition of the oils. Results revealed both of oils to possess degrees of antibacterial activity against Gram (+) and Gram (-) bacteria. T. vulgaris EO showed better inhibitory effects than E. globulus essential oil. GC analysis of T. vulgaris resulted in thymol as the oil major compound whereas GC/MS assay exhibited eucalyptol as the most abundant constitute of E. globulus EO. These results support previous studies on these oils and suggest an additional option to treat MRSA infections. Clinical and further analytical trials of these data are necessary to confirm the obtained outcomes. Copyright 2009. Published by Elsevier GmbH.

  19. Epidemiological Validation of Pulsed-Field Gel Electrophoresis Patterns for Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Blanc, D. S.; Struelens, M. J.; Deplano, A.; De Ryck, R.; Hauser, P. M.; Petignat, C.; Francioli, P.

    2001-01-01

    To determine the stability of pulsed-field gel electrophoresis (PFGE) patterns of methicillin-resistant Staphylococcus aureus in the nosocomial setting, we analyzed isolates from long-term carriers (>1 month) and from patients involved in well-defined nosocomial epidemics. The number of fragment differences between the first isolate and subsequent isolates in long-term carriers showed a bimodal distribution, with one group having 0 to 6 fragment differences and the other group having 14 to 24 fragment differences. The PFGE patterns of isolates involved in epidemics also presented a similar bimodal distribution of the number of fragment differences. Typing these isolates with another molecular method (inter-IS256 PCR) showed that isolates of the first group (i.e., with 1 to 6 fragment differences) were clonally related, whereas the second group (with 14 to 24 fragment differences) could be considered genetically different. Among long-term carriers with clonally related isolates, 74 of 84 (88%) of consecutive isolates showed indistinguishable patterns, whereas 10 of 84 (12%) showed related patterns differing by one to six fragments. Moreover, the frequency of apparition of related patterns is higher when the time between the first and the subsequent isolate is longer. During seven nosocomial epidemics lasting from 1 to 15 months, only 2 of 120 isolates (1.7%) showed a pattern which was different, although related, from the predominant one involved in each of these outbreaks. PMID:11574553

  20. Reconsidering contact precautions for endemic methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus.

    PubMed

    Morgan, Daniel J; Murthy, Rekha; Munoz-Price, L Silvia; Barnden, Marsha; Camins, Bernard C; Johnston, B Lynn; Rubin, Zachary; Sullivan, Kaede V; Shane, Andi L; Dellinger, E Patchen; Rupp, Mark E; Bearman, Gonzalo

    2015-10-01

    Whether contact precautions (CP) are required to control the endemic transmission of methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) in acute care hospitals is controversial in light of improvements in hand hygiene, MRSA decolonization, environmental cleaning and disinfection, fomite elimination, and chlorhexidine bathing. To provide a framework for decision making around use of CP for endemic MRSA and VRE based on a summary of evidence related to use of CP, including impact on patients and patient care processes, and current practices in use of CP for MRSA and VRE in US hospitals. A literature review, a survey of Society for Healthcare Epidemiology of America Research Network members on use of CP, and a detailed examination of the experience of a convenience sample of hospitals not using CP for MRSA or VRE. Hospital epidemiologists and infection prevention experts. No high quality data support or reject use of CP for endemic MRSA or VRE. Our survey found more than 90% of responding hospitals currently use CP for MRSA and VRE, but approximately 60% are interested in using CP in a different manner. More than 30 US hospitals do not use CP for control of endemic MRSA or VRE. Higher quality research on the benefits and harms of CP in the control of endemic MRSA and VRE is needed. Until more definitive data are available, the use of CP for endemic MRSA or VRE in acute care hospitals should be guided by local needs and resources.

  1. Evaluation of antiseptics by the modified phenol coefficient method: sensitivity of methicillin-resistant Staphylococcus aureus.

    PubMed

    Sasatsu, M; Shimizu, K; Noguchi, N; Kono, M

    1994-01-01

    The relationship between an effective concentration and the duration of exposure to antiseptics was evaluated in strains of Staphylococcus aureus with a known genetic background, which include methicillin-resistant strains, using a modified version of the phenol coefficient method as part of an effort to investigate the antiseptic resistance of S. aureus. Chlorhexidine digluconate killed an antiseptic-sensitive strain within 1.5 min at 22 degrees C at a standard concentration (0.1%), whereas resistant strains still survived after 1.5 min. Povidone-iodine killed the sensitive strain within 1.5 min at a concentration of 0.1%, whereas it took this agent 3.0 and 4.5 min to kill low- and high-level resistant strains, respectively, at a concentration of 0.8%. These results indicate that the modified phenol coefficient method used is suitable for the evaluation of the sensitivity of microorganisms to antiseptics. An antiseptic-resistant chain that was associated with the ebr gene exhibited cross-resistance to povidone-iodine.

  2. Fulminant necrotising fasciitis by community-acquired methicillin-resistant Staphylococcus aureus

    PubMed Central

    Non, Lemuel; Kosmin, Aaron

    2015-01-01

    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. PMID:25824286

  3. 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

  4. Antimicrobial Drugs and Community-acquired Methicillin-Resistant Staphylococcus aureus, United Kingdom

    PubMed Central

    Schneider-Lindner, Verena; Delaney, J. A.; Dial, Sandra; Dascal, Andre

    2007-01-01

    We report results of a case–control study of the association between receipt of antimicrobial agents and diagnosis of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) in the United Kingdom. Eligible adults, selected from the General Practice Research Database, had no previous diagnosis of MRSA, no hospitalization in the past 2 years, and >2 years of follow-up recorded in the database. For 2000–2004, we identified 1,981 MRSA case-patients and 19,779 matched control-patients. The odds ratios (ORs) and 95% confidence intervals (CIs) of MRSA diagnosis for patients who were prescribed 1, 2–3, or >4 antimicrobial drugs were 1.57 (CI 1.36–1.80), 2.46 (CI 2.15–2.83), and 6.24 (CI 5.43–7.17), respectively. Risk for community-acquired MRSA increased with number of antimicrobial drug prescriptions, appeared to vary according to antimicrobial drug classes prescribed the previous year, and was highest for quinolones (OR 3.37, CI 2.80–4.09) and macrolides (OR 2.50, CI 2.14–2.91). PMID:18214170

  5. Commercially Distributed Meat as a Potential Vehicle for Community-Acquired Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Narimatsu, Hiroshi; Suzuki, Masahiro; Higuchi, Wataru; Yamamoto, Tatsuo; Taniguchi, Hatsumi

    2012-01-01

    The incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection has been increasing; however, the sources of infection remain unclear. Therefore, we investigated the involvement of meat as a possible mediator of CA-MRSA infection. We examined the distribution of MRSA strains in commercially distributed raw meat samples (n = 197) and diarrheal stool samples of outpatients (n = 1,287) that were collected in Oita Prefecture, Japan, between 2003 and 2009 for routine legal inspections. Fourteen MRSA strains were isolated from three meat and 11 stool samples. Among these, seven isolates from three meat and four stool samples exhibited the same epidemiological marker profiles [coagulase type III, staphylococcal enterotoxin C, staphylococcal chromosomal cassette mec (SCCmec) type IV, ST8, spa type 606 (t1767), and toxic shock syndrome toxin-1 (TSST-1) producing type]. Furthermore, of the seven strains, three isolates from two meat samples and one stool sample collected in 2007 exhibited completely identical characteristics with respect to phage open reading frame (ORF) typing, pulsed-field gel electrophoresis, and drug susceptibility profiles. The results suggest that commercially distributed meat could play a role in the prevalence of CA-MRSA in the community. PMID:22307310

  6. Virulence gene typing of methicillin-resistant Staphylococcus aureus as a complement in epidemiological typing.

    PubMed

    Nowrouzian, Forough L; Karami, Nahid; Welinder-Olsson, Christina; Ahrén, Christina

    2013-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) has widely spread to all parts of the world. For surveillance and effective infection control molecular typing is required. We have evaluated the utility of virulence gene determination as a complementary tool for epidemiological typing of MRSA in relation to spa-typing and pulsed-field gel electrophoresis (PFGE). We assessed 63 community-acquired MRSA (CA-MRSA) isolates detected in the West part of Sweden for 30 virulence factor genes (VF) and agr allele variations by serial polymerase chain reaction (PCR) assays. These isolates belonged to sequence types (ST) 8, 80, 45 and 30 as classified by multilocus sequence typing. The isolates in each spa-type and PFGE-type were examined over an extended time-period and constituted a varying number of PFGE-subtypes (5-14) and spa-types (3-11) within four major PFGE types. Each ST had a unique VF profile. For isolates within a major PFGE type showing high diversity both in PFGE subtypes and spa the VF profile varied as well in contrast to those with low diversity where no alterations were seen. Thus, the accuracy of each typing method does not only vary by the method per se but is rather dependent on the genetic repertoire of the typed strains and genes evaluated. For strains demonstrating high diversity VF typing may be a useful complement in the epidemiological investigations, and may highlight the accurate discriminatory power of spa or PFGE typing.

  7. Nosocomial methicillin-resistant Staphylococcus aureus endocarditis with splenic abscess in a pregnant woman.

    PubMed

    Ozkurt, Zulal; Erkut, Bilgehan; Kadanali, Ayten; Ates, Azman; Yekeler, Ibrahim

    2005-10-01

    A 36-year-old, 7-week-gravida patient with catheter-related nosocomial infective endocarditis due to methicillin-resistant Staphylococcus aureus (MRSA) is presented in this paper. The patient was admitted to our hospital because of carbon monoxide intoxication. After 14 days, MRSA catheter-related bacteremia developed. The central venous catheter was immediately removed, and teicoplanin therapy was started. Because of persistent fever, leukocytosis, and high C-reactive protein values, endocarditis was suspected. A transesophageal echocardiogram revealed 19-mm vegetation on her mitral valve, confirming the diagnosis of endocarditis. Gentamicin and rifampicin were added to the therapy regimen, and the dose of teicoplanin was increased to 12 mg/kg-day. After 8 days, a splenic abscess was detected by ultrasonography. Vegetation excision, mitral valve replacement by open-heart surgery and splenectomy were performed in the same operation. Antibiotherapy was continued for 6 weeks after surgery, and the patient's condition improved. The development of endocarditis could be prevented by proper clinical practices.

  8. [Methicillin-resistant Staphylococcus aureus endocarditis following patch closure of ventricular septal defect].

    PubMed

    Imoto, Y; Sese, A; Ueno, Y; Todoroki, H; Ueda, Y; Joho, K

    1992-02-01

    Mediastinitis due to methicillin-resistant Staphylococcus aureus was found on the ninth postoperative day after patch closure of ventricular septal defect (VSD) in a six-month-old girl. Intravenous administration of vancomycin and debridement of the wound followed by irrigation with povidone iodine and vancomycin led to wound disinfection, but blood cultures continued positive. On the 22nd postoperative day, an echocardiographic examination revealed vegetations in the right ventricle. An emergency open heart operation was undergone. The largest vegetation was 1 x 2 cm in size, originating from the intracardiac patch used for closure of the VSD. The pulmonary and tricuspid valves were also involved. After removal of the infected tissues, including the two cusps of the pulmonary valve and a part of the tricuspid valve, the ventricular septal defect was closed again with a woven Dacron patch. The defect in the tricuspid valve was repaired. Postoperative examinations revealed severe pulmonary regurgitation and mild tricuspid regurgitation, but the cardiac function was good and neither vegetation nor leakage around the patch was recognized.

  9. 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

  10. 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.

  11. Activity of the thiopeptide antibiotic nosiheptide against contemporary strains of methicillin-resistant Staphylococcus aureus.

    PubMed

    Haste, Nina M; Thienphrapa, Wdee; Tran, Dan N; Loesgen, Sandra; Sun, Peng; Nam, Sang-Jip; Jensen, Paul R; Fenical, William; Sakoulas, George; Nizet, Victor; Hensler, Mary E

    2012-12-01

    The rapid rise in antimicrobial resistance in bacteria has generated an increased demand for the development of novel therapies to treat contemporary infections, especially those caused by methicillin-resistant Staphylococcus aureus (MRSA). However, antimicrobial development has been largely abandoned by the pharmaceutical industry. We recently isolated the previously described thiopeptide antibiotic nosiheptide from a marine actinomycete strain and evaluated its activity against contemporary clinically relevant bacterial pathogens. Nosiheptide exhibited extremely potent activity against all contemporary MRSA strains tested including multiple drug-resistant clinical isolates, with MIC values 0.25 mg l(-1). Nosiheptide was also highly active against Enterococcus spp. and the contemporary hypervirulent BI/NAP1/027 strain of Clostridium difficile but was inactive against most Gram-negative strains tested. Time-kill analysis revealed nosiheptide to be rapidly bactericidal against MRSA in a concentration- and time-dependent manner, with a nearly 2-log kill noted at 6 h at 10 × MIC. Furthermore, nosiheptide was found to be non-cytotoxic against mammalian cells at >100 × MIC, and its anti-MRSA activity was not inhibited by 20% human serum. Notably, nosiheptide exhibited a significantly prolonged post-antibiotic effect against both healthcare- and community-associated MRSA compared with vancomycin. Nosiheptide also demonstrated in vivo activity in a murine model of MRSA infection, and therefore represents a promising antibiotic for the treatment of serious infections caused by contemporary strains of MRSA.

  12. Genetics of staphylococcal enterotoxin B in methicillin-resistant isolates of Staphylococcus aureus.

    PubMed Central

    Shafer, W M; Iandolo, J J

    1979-01-01

    Biophysical and genetic analysis of staphylococcal enterotoxin B (SEB) synthesis in 16 methicillin-resistant (Mecr) Staphylococcus aureus isolates demonstrated that the toxin gene (entB) can occupy either a plasmid or chromosomal locus. Biophysical analysis of the plasmid deoxyribonucleic acid content of these strains by agarose gel electrophoresis revealed the presence of a 1.15-megadalton plasmid in six isolates that appears to contain the entB gene. Genetic manipulation of SEB synthesis by transduction and elimination procedures demonstrated that this plasmid is critical for enterotoxigenesis. Nevertheless, the majority of the Mecr SEB+ isolates (62.5%) analyzed in this investigation were found to lack the 1.15-megadalton plasmid. In at least two of these strains (COL and 57-dk), transduction and elimination procedures showed that entB was chromosomal. Genetic studies involving strains harboring either a plasmid or chromosomal entB gene demonstrated that toxin synthesis was coeliminated with mec. However, analysis of the entB and mec loci by transformation or transduction showed that the genes are not closely linked. On the other hand, transduction of entB, regardless of the donor, was observed when both mec and the Tcr plasmid were jointly cotransduced. This finding suggests that, during transduction, a transient association between entB, mec, and the Tcr plasmid may exist. Images PMID:259057

  13. Interpretation of Epithelial Lining Fluid Concentrations of Antibiotics against Methicillin Resistant Staphylococcus aureus.

    PubMed

    Kiem, Sungmin; Schentag, Jerome J

    2014-12-01

    Although antibiotics whose epithelial lining fluid (ELF) concentrations are reported high tend to be preferred in treatment of pneumonia, measurement of ELF concentrations of antibiotics could be misled by contamination from lysis of ELF cells and technical errors of bronchoalveolar lavage (BAL). In this review, ELF concentrations of anti-methicillin resistant Staphylococcus aureus (MRSA) antibiotics were interpreted considering above confounding factors. An equation used to explain antibiotic diffusion into CSF (cerebrospinal fluid) was adopted: ELF/free serum concentration ratio = 0.96 + 0.091 × ln (partition coefficient / molecular weight(1/2)). Seven anti-MRSA antibiotics with reported ELF concentrations were fitted to this equation to see if their ELF concentrations were explainable by the penetration capacity only. Then, outliers were modeled under the assumption of varying contamination from lysed ELF cells (test range 0-10% of ELF volume). ELF concentrations of oritavancin, telavancin, tigecycline, and vancomycin were well described by the diffusion equation, with or without additional impact from cell lysis. For modestly high ELF/free serum concentration ratio of linezolid, technical errors of BAL should be excluded. Although teicoplanin and iclaprim showed high ELF/free serum ratios also, their protein binding levels need to be cleared for proper interpretation. At the moment, it appears very premature to use ELF concentrations of anti-MRSA antibiotics as a relevant guide for treatment of lung infections by MRSA.

  14. 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

  15. An outbreak of methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit.

    PubMed

    Saiman, Lisa; Cronquist, Alicia; Wu, Fann; Zhou, Juyan; Rubenstein, David; Eisner, William; Kreiswirth, Barry N; Della-Latta, Phyllis

    2003-05-01

    To describe the epidemiologic and molecular investigations that successfully contained an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in a neonatal intensive care unit (NICU). Isolates of MRSA were typed by pulsed-field gel electrophoresis (PFGE) and S. aureus protein A (spa). A level III-IV, 45-bed NICU located in a children's hospital within a medical center. Incident cases had MRSA isolated from clinical cultures (eg, blood) or surveillance cultures (ie, anterior nares). Infected and colonized infants were placed on contact precautions, cohorted, and treated with mupirocin. Surveillance cultures were performed for healthcare workers (HCWs). Colonized HCWs were treated with topical mupirocin and hexachlorophene showers. From January to March 2001, the outbreak strain of MRSA, PFGE clone B, was harbored by 13 infants. Three (1.3%) of 235 HCWs were colonized with MRSA. Two HCWs, who rotated between the adult and the pediatric facility, harbored clone C. One HCW, who exclusively worked in the children's hospital, was colonized with clone B. From January 1999 to November 2000, 22 patients hospitalized in the adult facility were infected or colonized with clone B. Spa typing and PFGE yielded concordant results. PFGE clone B was identified as spa type 16, associated with outbreaks in Brazil and Hungary. A possible route of MRSA transmission was elucidated by molecular typing. MRSA appears to have been transferred from our adult facility to our pediatric facility by a rotating HCW. Spa typing allowed comparison of our institution's MRSA strains with previously characterized outbreak clones.

  16. Nosocomial transmission of methicillin-resistant Staphylococcus aureus from a mother to her preterm quadruplet infants.

    PubMed

    Morel, Anne-Sophie; Wu, Fann; Della-Latta, Phyllis; Cronquist, Alicia; Rubenstein, David; Saiman, Lisa

    2002-05-01

    Patient-to-patient transmission of methicillin-resistant Staphylococcus aureus (MRSA) in neonatal intensive care units (NICUs) has been well described. We report the first documented outbreak of probable transmission of MRSA from a mother to 3 of her preterm quadruplet infants postnatally. Routine surveillance of clinical microbiologic laboratory reports revealed an increased incidence of MRSA infections in our NICU, including 3 of 4 preterm quadruplets. Surveillance cultures of the anterior nares of all patients and the quadruplets' parents were performed to detect MRSA carriage. The isolates were typed by pulsed-field gel electrophoresis with the restriction endonuclease SmaI. Infection control strategies included mupirocin treatment and contact isolation precautions for infected/colonized infants. Clinical cultures from infants A, C, and D and surveillance cultures of the quadruplets' mother and 2 additional unrelated infants grew the same clone of MRSA. The mother's only identified risk factors for MRSA acquisition were 2 prepartum hospitalizations related to the multiple gestation and previous treatment with antibiotics. All anterior nares cultures were negative for MRSA after mupirocin treatment. Use of gowns and gloves by the family members of women with multiple gestations should be recommended to prevent transmission of potential pathogens in the NICU.

  17. Methicillin-resistant Staphylococcus aureus screening by online immunometric monitoring of bacterial growth under selective pressure.

    PubMed

    Stenholm, Teppo; Hakanen, Antti J; Vaarno, Jonne; Pihlasalo, Sari; Terho, Perttu; Hänninen, Pekka E; Vuopio-Varkila, Jaana; Huovinen, Pentti; Kotilainen, Pirkko

    2009-12-01

    Rapid, high-throughput screening tools are needed to contain the spread of hospital-acquired methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) strains. Most techniques used in current clinical practice still require time-consuming culture for primary isolation of the microbe. We present a new phenotypic assay for MRSA screening. The technique employs a two-photon excited fluorescence (TPX) detection technology with S. aureus-specific antibodies that allows the online monitoring of bacterial growth in a single separation-free process. Different progressions of fluorescence signals are recorded for methicillin-susceptible and -resistant strains when the growth of S. aureus is monitored in the presence of cefoxitin. The performance of the new technique was evaluated with 20 MRSA strains, 6 methicillin-susceptible S. aureus strains, and 7 coagulase-negative staphylococcal strains and two different monoclonal S. aureus-specific antibodies. When either of these antibodies was used, the sensitivity and the specificity of the TPX assay were 100%. All strains were correctly classified within 8 to 12 h, and up to 70 samples were simultaneously analyzed on a single 96-well microtiter plate. As a phenotypic method, the TPX assay is suited for screening purposes. The final definition of methicillin resistance in any S. aureus strain should be based on the presence of the mecA gene. The main benefit afforded by the initial use of the TPX methodology lies in its low cost and applicability to high-throughput analysis.

  18. Methicillin-Resistant Staphylococcus aureus Screening by Online Immunometric Monitoring of Bacterial Growth under Selective Pressure▿

    PubMed Central

    Stenholm, Teppo; Hakanen, Antti J.; Vaarno, Jonne; Pihlasalo, Sari; Terho, Perttu; Hänninen, Pekka E.; Vuopio-Varkila, Jaana; Huovinen, Pentti; Kotilainen, Pirkko

    2009-01-01

    Rapid, high-throughput screening tools are needed to contain the spread of hospital-acquired methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) strains. Most techniques used in current clinical practice still require time-consuming culture for primary isolation of the microbe. We present a new phenotypic assay for MRSA screening. The technique employs a two-photon excited fluorescence (TPX) detection technology with S. aureus-specific antibodies that allows the online monitoring of bacterial growth in a single separation-free process. Different progressions of fluorescence signals are recorded for methicillin-susceptible and -resistant strains when the growth of S. aureus is monitored in the presence of cefoxitin. The performance of the new technique was evaluated with 20 MRSA strains, 6 methicillin-susceptible S. aureus strains, and 7 coagulase-negative staphylococcal strains and two different monoclonal S. aureus-specific antibodies. When either of these antibodies was used, the sensitivity and the specificity of the TPX assay were 100%. All strains were correctly classified within 8 to 12 h, and up to 70 samples were simultaneously analyzed on a single 96-well microtiter plate. As a phenotypic method, the TPX assay is suited for screening purposes. The final definition of methicillin resistance in any S. aureus strain should be based on the presence of the mecA gene. The main benefit afforded by the initial use of the TPX methodology lies in its low cost and applicability to high-throughput analysis. PMID:19752281

  19. Biofilm density and detection of biofilm-producing genes in methicillin-resistant Staphylococcus aureus strains.

    PubMed

    Szczuka, Ewa; Urbańska, Katarzyna; Pietryka, Marta; Kaznowski, Adam

    2013-01-01

    Many serious diseases caused by Staphylococcus aureus appear to be associated with biofilms. Therefore, we investigated the biofilm-forming ability of the methicillin-resistant S. aureus (MRSA) isolates collected from hospitalized patients. As many as 96 % strains had the ability to form biofilm in vitro. The majority of S. aureus strains formed biofilm in ica-dependent mechanism. However, 23 % of MRSA isolates formed biofilm in ica-independent mechanism. Half of these strains carried fnbB genes encoding surface proteins fibronectin-binding protein B involved in intercellular accumulation and biofilm development in S. aureus strains. The biofilm structures were examined via confocal laser scanning microscopy (CLSM) and three-dimensional structures were reconstructed. The images obtained in CLSM revealed that the biofilm created by ica-positive strains was different from biofilm formed by ica-negative strains. The MRSA population showed a large genetic diversity and we did not find a single clone that occurred preferentially in hospital environment. Our results demonstrated the variation in genes encoding adhesins for the host matrix proteins (elastin, laminin, collagen, fibronectin, and fibrinogen) and in the gene involved in biofilm formation (icaA) within the majority of S. aureus clones.

  20. 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.

  1. Modeling methicillin-resistant Staphylococcus aureus in hospitals: transmission dynamics, antibiotic usage and its history.

    PubMed

    Chamchod, Farida; Ruan, Shigui

    2012-06-27

    Methicillin-resistant Staphylococcus aureus (MRSA) is endemic in many hospital settings, posing substantial threats and economic burdens worldwide. We propose mathematical models to investigate the transmission dynamics of MRSA and determine factors that influence the prevalence of MRSA infection when antibiotics are given to patients to treat or prevent infections with either MRSA itself or other bacterial pathogens. Our results suggest that: (i) MRSA always persists in the hospital when colonized and infected patients are admitted; (ii) the longer the duration of treatment of infected patients and the lower the probability of successful treatment will increase the prevalence of MRSA infection; (iii) the longer the duration of contamination of health care workers (HCWs) and the more their contacts with patients may increase the prevalence of MRSA infection; (iv) possible ways to control the prevalence of MRSA infection include treating patients with antibiotic history as quickly and efficiently as possible, screening and isolating colonized and infected patients at admission, and compliance with strict hand-washing rules by HCWs. Our modeling studies offer an approach to investigating MRSA infection in hospital settings and the impact of antibiotic history on the incidence of infection. Our findings suggest important influences on the prevalence of MRSA infection which may be useful in designing control policies.

  2. Modeling methicillin-resistant Staphylococcus aureus in hospitals: Transmission dynamics, antibiotic usage and its history

    PubMed Central

    2012-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) is endemic in many hospital settings, posing substantial threats and economic burdens worldwide. Methods We propose mathematical models to investigate the transmission dynamics of MRSA and determine factors that influence the prevalence of MRSA infection when antibiotics are given to patients to treat or prevent infections with either MRSA itself or other bacterial pathogens. Results Our results suggest that: (i) MRSA always persists in the hospital when colonized and infected patients are admitted; (ii) the longer the duration of treatment of infected patients and the lower the probability of successful treatment will increase the prevalence of MRSA infection; (iii) the longer the duration of contamination of health care workers (HCWs) and the more their contacts with patients may increase the prevalence of MRSA infection; (iv) possible ways to control the prevalence of MRSA infection include treating patients with antibiotic history as quickly and efficiently as possible, screening and isolating colonized and infected patients at admission, and compliance with strict hand-washing rules by HCWs. Conclusion Our modeling studies offer an approach to investigating MRSA infection in hospital settings and the impact of antibiotic history on the incidence of infection. Our findings suggest important influences on the prevalence of MRSA infection which may be useful in designing control policies. PMID:22738359

  3. Efficacy of Combined Vancomycin and Fosfomycin against Methicillin-Resistant Staphylococcus aureus in Biofilms In Vivo

    PubMed Central

    Wang, Li; Zhang, Han-Bo; Chen, Qian; Liu, Hua; Tang, Xun; Jin, Tao; Zhu, Chong-Tao; Li, Fu-Bing; Sun, Lin-Hui; Xu, Xin-Ming; Xu, Yong-Qing

    2014-01-01

    Infection by methicillin-resistant Staphylococcus aureus (MRSA) is a life-threatening condition, and formation of biofilms can lead to treatment failure in a clinical setting. The aim of this study was to demonstrate the in vivo bactericidal effects of a combination of vancomycin (VAN) and fosfomycin (FOS) against MRSA in a rat carboxymethyl cellulose-pouch biofilm model. The results of the time-kill assay showed that the combination therapy was capable of killing at low minimal inhibitory concentrations (MIC) (½× MIC VAN +1× MIC FOS and 1× MIC VAN + 1× MIC FOS). In the in vivo study, a synergistically bactericidal effect was observed when using the combination therapy on MRSA embedded in the mature biofilm model. In comparison with the untreated control group and the groups receiving either VAN or FOS alone, the rats treated with combination therapy had lower MRSA colony counts in exudates from the pouch, lower white blood cell and neutrophil counts, and C-reactive protein (CRP) in peripheral blood. Furthermore, histological analysis of the pouch wall indicated combination therapy resulted in disappearance of biofilm-like structures, marked decrease in necrosis, and formation of granular tissue. In conclusion, the combination of VAN with FOS had a synergistic bactericidal effect on chronic MRSA infection embedded in biofilm, providing an alternative approach to treating this condition. PMID:25551618

  4. Rapid detection of methicillin-resistant Staphylococcus aureus strains not identified by slide agglutination tests.

    PubMed Central

    Kuusela, P; Hildén, P; Savolainen, K; Vuento, M; Lyytikäinen, O; Vuopio-Varkila, J

    1994-01-01

    Seventy-nine methicillin-resistant Staphylococcus aureus (MRSA) strains, isolated during 1980 to 1990, were classified as MRSA Aggl- (14 strains) and MRSA Aggl+ (65 strains) strains on the basis of test results in slide agglutination assays designed to detect fibrinogen-binding protein (clumping factor) and protein A on the staphylococcal surface. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that lysostaphin digests of MRSA Aggl- strains contained a high-molecular-weight protein which was not detected in digests of MRSA Aggl+ strains. Immunization of rabbits with an MRSA Aggl- strain produced an antiserum which agglutinated all MRSA Aggl- strains and also 64 of 65 MRSA Aggl+ strains. Only 1 of 68 coagulase-negative staphylococci showed agglutination in this assay. The anti-MRSA Aggl- antiserum reacted mainly with a 230-kDa staphylococcal surface protein but also with a 175-kDa protein, probably formed by proteolysis of the former and a few slightly smaller proteins. These could not be immunologically detected in lysostaphin digests of MRSA Aggl+ strains. Purified antibodies reacting with the 230-kDa protein agglutinated all MRSA Aggl- strains, indicating that the protein is located on the surfaces of staphylococci. The results suggest a tentative role for the 230-kDa protein or its fragments as a novel target to develop more efficient rapid identification methods for S. aureus, including MRSA. Images PMID:8126170

  5. Methicillin-resistant Staphylococcus aureus and infection control for restorative dental treatment in nursing homes.

    PubMed

    Hall, David L

    2003-01-01

    The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in nursing home residents now averages 20-35%. This includes both numerous asymptomatic mostly unidentified carriers, and the occasional patient with an active infection. Among the most common sites for positive MRSA colonization are the nares and mouth (saliva). Ohio State University (OSU) dental students perform routine restorative dental care onsite in local nursing homes using portable equipment including handpieces that can generate aerosols. Using a series of cultured test swabs and plates, this pilot study suggests that protection for both dental health care personnel and patients are provided by the following: 1. universal barrier precautions (for example, gloves, gowns, masks, hats, facial shields, glasses), 2. surface disinfectants, 3. pre-op 0.12% chlorhexidene mouth rinses, 4. high volume evacuation, 5. perioral skin scrubs. Additional infection control methods, techniques and equipment were evaluated and compared including rubber dam isolation, hand excavation and bond technique, high-speed air turbine and electric "high" speed handpiece. There was no indication of a special tendency or heightened ability of MRSA to aerosolize.

  6. [Clinical features and outcome of community-acquired methicillin-resistant Staphylococcus aureus pneumonia].

    PubMed

    Obed, Mora; García-Vidal, Carolina; Pessacq, Pedro; Mykietiuk, Analia; Viasus, Diego; Cazzola, Laura; Domínguez, M Angeles; Calmaggi, Anibal; Carratalà, Jordi

    2014-01-01

    The aim of this study is to describe the epidemiological and clinical features, treatment and prognosis of community-acquired pneumonia (CAP) caused by methicillin-resistant Staphylococcus aureus (MRSA) in two different geographic regions where community-acquired MRSA (CA-MRSA) infections have different frequencies. Observational study of patients admitted to two hospitals (one in Argentina, the other in Spain) between March 2008 and June 2012. We documented 16 cases of CAP caused by MRSA. MRSA accounted for 15 of 547 (2.7%) cases of CAP in Hospital Rodolfo Rossi and 1 of 1258 (0,08%) cases at the Hospital Universitari de Bellvitge (P ≤ .001). Most patients were young and previously healthy. Multilobar infiltrates, cavitation and skin and soft tissue involvement were frequent. All patients had positive blood cultures. Five patients required admission to the intensive care unit. Early mortality (≤ 48 hours) was 19%, and overall mortality (≤ 30 days) was 25%. CAP caused by MRSA causes high morbidity and mortality rates. It should be suspected in areas with a high prevalence of CA-MRSA infections, and especially in young and healthy patients who present with multilobar pneumonia with cavitation. Mortality is mainly related to septic shock and respiratory failure and occurs early in most cases. Copyright © 2012 Elsevier España, S.L. All rights reserved.

  7. 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

  8. Livestock Origin for a Human Pandemic Clone of Community-Associated Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Spoor, Laura E.; McAdam, Paul R.; Weinert, Lucy A.; Rambaut, Andrew; Hasman, Henrik; Aarestrup, Frank M.; Kearns, Angela M.; Larsen, Anders R.; Skov, Robert L.; Fitzgerald, J. Ross

    2013-01-01

    ABSTRACT The importance of livestock as a source of bacterial pathogens with the potential for epidemic spread in human populations is unclear. In recent years, there has been a global increase in community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections of healthy humans, but an understanding of the different evolutionary origins of CA-MRSA clones and the basis for their recent expansion is lacking. Here, using a high-resolution phylogenetic approach, we report the discovery of two emergent clones of human epidemic CA-MRSA which resulted from independent livestock-to-human host jumps by the major bovine S. aureus complex, CC97. Of note, one of the new clones was isolated from human infections on four continents, demonstrating its global dissemination since the host jump occurred over 40 years ago. The emergence of both human S. aureus clones coincided with the independent acquisition of mobile genetic elements encoding antimicrobial resistance and human-specific mediators of immune evasion, consistent with an important role for these genetic events in the capacity to survive and transmit among human populations. In conclusion, we provide evidence that livestock represent a reservoir for the emergence of new human-pathogenic S. aureus clones with the capacity for pandemic spread. These findings have major public health implications highlighting the importance of surveillance for early identification of emergent clones and improved transmission control measures at the human-livestock interface. PMID:23943757

  9. The Economic Burden of Community-Associated Methicillin-Resistant Staphylococcus aureus (CA-MRSA)

    PubMed Central

    Lee, Bruce Y.; Singh, Ashima; David, Michael Z.; Bartsch, Sarah M.; Slayton, Rachel B.; Huang, Susan S.; Zimmer, Shanta M.; Potter, Margaret A.; Macal, Charles M.; Lauderdale, Diane S.; Miller, Loren G.; Daum, Robert S.

    2012-01-01

    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 $2,277 – $3,200 and society $7,070 – $20,489, depending on patient age. In the United States (US), CA-MRSA imposes an annual burden of $478 million - 2.2 billion on third-party payers and $1.4 billion - 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), respectively. Hospitalization rates and mortality are important cost drivers. CA-MRSA confers a substantial economic burden to 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. PMID:22712729

  10. 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

  11. Detection of Small Colony Variants Among Methicillin-Resistant Staphylococcus aureus Blood Isolates.

    PubMed

    Yagci, Server; Sancak, Banu; Hascelik, Gulsen

    2016-12-01

    Staphylococcus aureus small colony variants (SCVs) are associated with chronic and persistent infections. Methicillin-resistant S. aureus (MRSA) SCVs cause more severe infections and mortality rates are higher in comparison with infections caused by MRSA. Our objective was to document the prevalence and phenotypical characteristics of SCVs among MRSA blood isolates. MRSA strains isolated from blood during 1999-2009 were evaluated retrospectively. Among 299 MRSA isolates, suspected colonies were inoculated onto Columbia blood agar and Schaedler agar. Columbia blood agar was incubated in normal atmosphere and Schaedler agar in 5-10% CO2, both at 35°C. If the small, nonpigmented, nonhemolytic colonies on Columbia blood agar were seen as normal-sized, hemolytic, and pigmented colonies on Schaedler agar, they were considered as MRSA SCVs. Six MRSA SCVs were detected. When subcultures were made, four of them reversed to phenotypically normal S. aureus, but two isolates were stable as SCV phenotype. The prevalence of SCVs among MRSA blood isolates was found as 6/299 (2%) with 2 (0.67%) stable. The detection of SCVs among MRSA blood isolates was reported from Turkey for the first time in this study. As the clinical significance of MRSA infections is well documented, evaluation of MRSA SCVs in clinical samples, especially from intensive care patients and those who have chronic and persistent infections are important to consider.

  12. Frequent isolation of methicillin resistant Staphylococcus aureus (MRSA) ST398 among healthy pigs in Portugal.

    PubMed

    Conceição, Teresa; de Lencastre, Hermínia; Aires-de-Sousa, Marta

    2017-01-01

    Although livestock-associated ST398 methicillin-resistant Staphylococcus aureus (MRSA) has been widely reported in different geographic regions, MRSA carriage studies among healthy pigs in Portugal are very limited. In total, 101 swine nasal samples from two Portuguese farms were screened for MRSA. In addition five swine workers (including one veterinary and one engineer) and four household members were nasally screened. The isolates were characterized by spa typing, SCCmec typing and MLST. All isolates were tested for antimicrobial susceptibility, presence of mecA and mecC genes, and virulence determinants. MRSA prevalence in swine was 99% (100/101), 80% (4/5) in swine workers and 25% (1/4) in household members. All isolates belonged to ST398 distributed over two spa types-t011 (57%) and t108 (42%). SCCmec type V was present in most of the isolates (n = 95; 82%) while 21 isolates amplified the mecA gene only and were classified as nontypeable. The majority of the isolates were resistant to tetracycline (100%), clindamycin (97%), erythromycin (96%), chloramphenicol (84%) and gentamycin (69%). Notably, 12% showed resistance to quinupristin-dalfopristin (MICs 3-8 μg/mL). Beta-hemolysin (81%) and gamma-hemolysin (74%) were the unique virulence determinants detected. None of the isolates harboured PVL or mecC gene. This study showed a massive occurrence of ST398-MRSA in two independent swine farms, highlighting its establishment among healthy pigs in Portugal.

  13. Methicillin-resistant Staphylococcus aureus isolates from surfaces and personnel at a hospital laundry facility.

    PubMed

    Michael, K E; No, D; Roberts, M C

    2016-09-01

    Examine a clinical laundry facility for the presence of methicillin-resistant Staphylococcus aureus (MRSA) on environmental surfaces and among personnel. Nasal and face samples along with surface samples were collected four times in 2015. MRSA isolates were confirmed using standardized biochemical assays and molecular characterization. MRSA was identified in 33/120 (28%) samples from the dirty and 3/120 (3%) samples from the clean environmental areas. MRSA isolates included: (dirty) ST5 SCCmec type II, ST8 SCCmec type IV, ST231 SCCmec type II, ST239 SCCmec type III, ST239 SCCmec type IV, ST256 SCCmec type IV and (clean) ST5 SCCmec type II and ST8 SCCmec type IV. Five different employees were MRSA positive, 4/8 (50%) from the dirty: and 1/15 (6·7%) from the clean, but there was a 10-fold higher MRSA carriage 6/22 (27%) dirty vs 1/38 (2·6%) clean when all 50 human samples were combined. MRSA prevalence was significantly higher (28 vs 3%) in dirty vs clean areas within the laundry facility suggesting a greater risk for personnel on the dirty side. This is the first report of isolation and characterization of MRSA from surfaces and personnel from a clinical laundry facility. © 2016 The Society for Applied Microbiology.

  14. 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

  15. Characteristics of SCCmec IV and V Methicillin-Resistant Staphylococcus aureus (MRSA) in Israel.

    PubMed

    Shitrit, Pnina; Openhaim, Michal; Reisfeld, Sharon; Paitan, Yossi; Regev-Yochay, Gili; Carmeli, Yehuda; Chowers, Michal

    2015-08-01

    Isolation of methicillin-resistant Staphylococcus aureus (MRSA) in healthy individuals is not common in Israel. In our hospital, about 30% of MRSA isolates were SCCmec types IV and V. To identify the demographic and clinical characteristics of patients carrying MRSA SCCmec type IV or V, and to compare them with each other and with those of patients with SCCmec types I-III. We conducted a case-control study that included 501 patients from whom MRSA was isolated: 254 with SCCmec type I, II, or III, and 243 isolates from SCCmec types IV or V. MRSA was isolated from surveillance cultures in 75% of patients and from a clinical site in 25%. The majority of our study population was elderly, from nursing homes, and with extensive exposure to health care. First, we compared characteristics of patients identified through screening. Statistically significant predictors of SCCmec V vs. IV were Arab ethnicity (OR 7.44, 95% CI 1.5-37.9) and hospitalization in the year prior to study inclusion (OR 5.7, 95% CI 1.9-16.9). No differences were found between patients with SCCmec types I-III and patients with SCCmec type IV or V. Analysis of the subset of patients who had clinical cultures yielded similar results. SCCmec types IV and V were common in the hospital setting although rare in the community. It seems that in Israel, SCCmec IV and V are predominantly health care-associated MRSA.

  16. MALDI-TOF MS fingerprinting allows for discrimination of major methicillin-resistant Staphylococcus aureus lineages.

    PubMed

    Wolters, Manuel; Rohde, Holger; Maier, Thomas; Belmar-Campos, Cristina; Franke, Gefion; Scherpe, Stefanie; Aepfelbacher, Martin; Christner, Martin

    2011-01-01

    Early detection of outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) and initiation of adequate infection control measures are important objectives in hospital hygiene. To reach these goals, prompt determination of epidemiologic relatedness of clinical MRSA isolates is essential. Genetic typing methods like pulsed-field gel electrophoresis (PFGE), spa typing, or multilocus sequence typing (MLST) have a high discriminatory power, however, these methods are time consuming and cost intensive. The aim of this study was to investigate the potential of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for discrimination of major MRSA lineages. By analysis of mass spectra from 25 representative MRSA isolates belonging to the 5 major hospital-acquired (HA) MRSA clonal complexes (CC5, CC8, CC22, CC30, CC45; deduced from spa typing), reproducible spectrum differences were observed at 13 characteristic m/z values allowing robust discrimination of the clonal complexes. When 60 independent clinical MRSA isolates were tested for the presence or absence of the 13 characteristic MALDI-TOF MS peaks, 15 different profiles (MALDI types) could be detected. Hierarchical clustering of the MALDI types showed high concordance with the clonal complexes. Our results suggest that MALDI-TOF MS has the potential to become a valuable first-line tool for inexpensive and rapid typing of MRSA in infection control.

  17. 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.

  18. Fluoroquinolones and the Risk for Methicillin-resistant Staphylococcus aureus in Hospitalized Patients1

    PubMed Central

    Gold, Howard S.; Hooper, David C.; Karchmer, A.W.; Carmeli, Yehuda

    2003-01-01

    To determine whether fluoroquinolone exposure is a risk factor for the isolation of Staphylococcus aureus and whether the effect is different for methicillin-resistant S. aureus (MRSA) versus methicillin-susceptible S. aureus (MSSA), we studied two case groups. The first case group included 222 patients with nosocomially acquired MRSA. The second case group included 163 patients with nosocomially acquired MSSA. A total of 343 patients admitted concurrently served as controls. Outcome measures were the adjusted odds ratio (OR) for isolation of MRSA and MSSA after fluoroquinolone exposure. Exposure to both levofloxacin (OR 5.4; p < 0.0001) and ciprofloxacin (OR 2.2; p < 0.003) was associated with isolation of MRSA but not MSSA. After adjustment for multiple variables, both drugs remained risk factors for MRSA (levofloxacin OR 3.4; p < 0.0001; ciprofloxacin OR 2.5; p = 0.005) but not MSSA. Exposure to levofloxacin or ciprofloxacin is a significant risk factor for the isolation of MRSA, but not MSSA. PMID:14718085

  19. 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.

  20. Staphylococcal chromosomal cassettes mec (SCCmec): A mobile genetic element in methicillin-resistant Staphylococcus aureus.

    PubMed

    Liu, Junyan; Chen, Dingqiang; Peters, Brian M; Li, Lin; Li, Bing; Xu, Zhenbo; Shirliff, Mark E

    2016-12-01

    Considered to be a potential "superbug", methicillin-resistant Staphylococcus aureus (MRSA) has been one of the major recent infectious pathogens and thus poses a challenge to hospital infection control. The mobile genetic element staphylococcal chromosomal cassette mec (SCCmec) carries both the mecA or mecC gene, encoding for a novel specific penicillin-binding protein (PBP2a), and site-specific recombinase genes ccrAB or/and ccrC. In MRSA, the acquisition of SCCmec leads to the resistance to the β-lactam antibiotics. As SCCmec plays a core role in the antimicrobial resistance characteristics, molecular epidemiology and evolution of MRSA, a thorough summary and comprehensive understanding of the prevalence and structural characteristics of SCCmec may aid in global surveillance, implementation and investigation on MRSA isolates, as well as further development of preventive and therapeutic approaches. Consequently, this review is aimed at describing the history, prevalence, types and subtypes, and current typing methods of SCCmec, with the focus on the typical structures of the SCCmec cassette.

  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. Molecular characterization of methicillin-resistant Staphylococcus aureus nasal isolates from Turkey.

    PubMed

    Kilic, Abdullah; Mert, Gurkan; Senses, Zeynep; Bedir, Orhan; Aydogan, Hakan; Basustaoglu, A Celal; Appelbaum, Peter C

    2008-11-01

    Methicillin-resistant Staphylococcus aureus (MRSA) colonize most frequently in the anterior nares of the nose and cause serious infections all over the world. The aim of this study was to determine the nasal carriage rate of S. aureus and MRSA strains in Turkish elementary school children. We also analyzed molecular characterizations of MRSA strains by using pulse field gel electrophoresis (PFGE), multi locus sequence typing (MLST), staphylococcal chromosomal cassette mec (SCCmec) typing, and detection of the Panton-valentine leucocidin (PVL) gene. The nasal swabs were obtained from 4,050 children during a 4 month period in Ankara. In vitro antimicrobial susceptibility testing to 1 mug oxacillin and 30 mug cefoxitin was determined by a disk diffusion method. We found that the 1,001 of 4,050 (24.7%) children were colonized with S. aureus. Three S. aureus strains were resistant to oxacillin and cefoxitin. The rate of MRSA among all children was 0.07%. The MRSA strains revealed three different PFGE pattern. All MRSA isolates by harbored the SCCmec type IV element, but not the PVL gene. The two MRSA isolate belonged to sequence type (ST) 30, whereas the other one was a unique type. The results of this study demonstrated that S. aureus nasal carriage rate was consistent with previous studies. However, MRSA carriage rate was low. This study also indicated that the ST30-type IV without PVL gene MRSA clone may be expected to spread in Turkish community.

  3. Synergism between Medihoney and Rifampicin against Methicillin-Resistant Staphylococcus aureus (MRSA)

    PubMed Central

    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

  4. 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

  5. Global Distribution of Panton-Valentine Leukocidin–positive Methicillin-resistant Staphylococcus aureus, 2006

    PubMed Central

    Bes, Michele; Meugnier, Helene; Lina, Gerard; Bozdogan, Bülent; Courvalin, Patrice; Reverdy, Marie-Elisabeth; Enright, Mark C.; Vandenesch, François; Etienne, Jerome

    2007-01-01

    We determined the agr type, multilocus sequence type, protein A gene type (spa typing), toxin gene profile, and antimicrobial drug resistance profile of 469 isolates of Panton-Valentine leukocidin–positive community-acquired methicillin-resistant Staphylococcus aureus isolates (PVL-positive CA-MRSA). The isolates had been collected from around the world from 1999 through 2005 by the French National Reference Center for Staphylococci. We found that some continent-specific clones described in 2003, such as clone ST8, have now spread all over the world. Likewise, some PVL-positive CA-MRSA have spread to several countries on various continents. New clones have emerged (e.g., ST377) on new genetic backgrounds. PVL-positive CA-MRSA that were usually susceptible to most antistaphylococcal antimicrobial agents have acquired new resistance determinants (e.g., to gentamicin) in certain countries. The major trait shared by all these clones is a short staphylococcal chromosomal cassette mec element of type IV or V. PMID:17553275

  6. Methicillin-resistant Staphylococcus aureus infected gluteal compartment syndrome with rhabdomyolysis in a bodybuilder.

    PubMed

    Woon, Colin Yl; Patel, Kushal R; Goldberg, Benjamin A

    2016-05-18

    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.

  7. Antimicrobial resistance pattern of methicillin-resistant Staphylococcus aureus in the food industry.

    PubMed

    Paludi, D; Vergara, A; Festino, A R; Di Ciccio, P; Costanzo, C; Conter, M; Zanardi, E; Ghidini, S; Ianieri, A

    2011-01-01

    There is increasing concern about the impact on public health of methicillin-resistant Staphylococcus aureus (MRSA) associated with animal food products. MRSA remains a serious problem because of the high incidence and multidrug resistance of the strains, even for strains isolated from foods, food environments and food handlers. The objectives of this study are: (i) to evaluate the susceptibility of S. aureus strains isolated from food, food handlers and food-processing environments to 14 antibiotics currently used in veterinary and human therapy; (ii) to assess the presence of the mecA gene. A total of 1007 samples were collected from food, food handlers, and environments and were analyzed for the presence of S. aureus. S. aureus was present in 165 of the 1007 samples. A total of 157 isolates were methicillin-susceptible S. aureus (MSSA) and 8 isolates were MRSA. In particular, out of 8 MRSA strains detected, 4 strains harboured the mecA gene. All MRSA strains were resistant to at least one of the tested antibiotics and 6 strains demonstrated multi-resistance. Considering the high level of resistances in S. aureus and the isolation of MRSA strains, the surveillance of antimicrobial resistance and the spreading of this pathogen is of crucial importance in the food production chain. These data are useful in improving background data on antimicrobial resistance of S. aureus isolated from food, processing environments and food handlers, supporting the prudent use of antibiotics and the development of international control programs.

  8. 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.

  9. Emergence of Community-Associated Methicillin-Resistant Staphylococcus aureus Carriage in Children in Cambodia

    PubMed Central

    Nickerson, Emma K.; Wuthiekanun, Vanaporn; Kumar, Varun; Amornchai, Premjit; Wongdeethai, Nattavut; Chheng, Kheng; Chantratita, Narisara; Putchhat, Hor; Thaipadungpanit, Janjira; Day, Nicholas P.; Peacock, Sharon J.

    2011-01-01

    We previously described the first reported isolation of methicillin-resistant Staphylococcus aureus (MRSA) (a case series of pediatric community-associated MRSA infections) in Cambodia. We define the rate of pediatric MRSA carriage in the same population and characterize the associated bacterial genotypes by using pulsed-field gel electrophoresis and multilocus sequence typing. A prospective cohort study of MRSA carriage conducted over one month at the Angkor Hospital for Children, Siem Reap, Cambodia, identified MRSA carriage in 87 (3.5%) of 2,485 children who came to the outpatient department, and 6 (4.1%) of 145 inpatients, including at least two with cases of nosocomial acquisition. Genotyping of all 93 MRSA isolates resolved 5 genotypes. Most (91%) isolates were assigned to sequence type 834. Only 28 (32%) of 87 MRSA carriers identified in the outpatient department had no history of recent healthcare contact. The study findings have important implications for healthcare in a setting where diagnostic microbiology and access to antimicrobial drugs with efficacy against MRSA are limited. PMID:21292906

  10. Methicillin-Resistant Staphylococcus aureus (MRSA) in Iran: A Systematic Review and Meta-analysis.

    PubMed

    Dadashi, Masoud; Nasiri, Mohammad Javad; Fallah, Fatemeh; Owlia, Parviz; Hajikhani, Bahareh; Emaneini, Mohammad; Mirpour, Mirsasan

    2017-09-20

    Methicillin-resistant Staphylococcus aureus (MRSA) remains one of the most prevalent multidrug-resistant organisms causing health care- infections. In Iran, limited data are available about how the prevalence of MRSA has changed over the past years. In the present study, we aimed to determine the exact prevalence of MRSA in different parts of Iran. Several databases including Medline, Embase, Web of sciences and Iranian databases were searched from Mar 2000 to Jan 2016 to identify studies addressing the prevalence of MRSA in Iran. Comprehensive meta-analysis (V2.2, Biostat) software was used to analyze the data. Of the 725 records identified from the databases, 31 studies fulfilled the eligibility criteria. The analyses showed that the prevalence of MRSA infections was 43.0% [95% confidence interval (95% CI) 36.3-50.0] among culture-positive cases of S. aureus in different parts of Iran. The further stratified analyses indicated that the prevalence of MRSA was higher in studies that were done after year 2000. Since high rates of MRSA infections was seen in our analysis, the regular surveillance of hospital associated infection, monitoring of antibiotic sensitivity pattern and formulation of definite antibiotic policy may facilitate more accurate action for prevention and control of MRSA. In particular, the introduction of MRSA screening based on rapid and reliable diagnosis during inpatient admission of patients is indispensable. Copyright © 2017. Published by Elsevier Ltd.

  11. [Antibiotic efficacies of combined uses of arbekacin and various antibiotics against methicillin-resistant Staphylococcus aureus].

    PubMed

    Deguchi, K; Yokota, N; Koguchi, M; Suzuki, Y; Suzuki, K; Fukayama, S; Ishihara, R; Oda, S

    1994-06-01

    Efficacies of combined uses of arbekacin(ABK) with other antibiotics against between 57 and 76 clinically isolated methicillin-resistant Staphylococcus aureus(MRSA) were examined. Other antibiotics tested were fosfomycin(FOM), 5 cephems(CEPs), 2 penicillins(PCs) and imipenem. Percentages of strains that grew at various combination of serially diluted drugs in a microdilution method were scored, and for each pair of drugs > or = MIC50 or > or = MIC90 was determined. FIC-indices were calculated at > or = MIC50. Bacterial growth was inhibited by low concentrations of ABK dose-dependently, while most of the strains tested were resistant to 9 other drugs. FIC-indices with ABK were lowest when used together with ampicillin (ABPC) (0.516) followed by combinations with cefotiam (CTM) and cefuzonam (CZON) (each, 0.53), and FOM (0.625). When combined with 0.5 microgram/ml of ABK, 0.5 microgram/ml of ABPC inhibited more than 50% of MRSA strains. CTM or CZON in combination with the same amount of ABK to 2 micrograms/ml inhibited more than 50% of MRSA. Thus ABPC was found to be the most efficient in combined use with ABK to inhibit clinical MRSA strains.

  12. Evolution and diversity of community-associated methicillin-resistant Staphylococcus aureus in a geographical region

    PubMed Central

    2011-01-01

    Background Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) was first reported in remote regions of Western Australia and is now the predominant MRSA isolated in the state. The objective of this study is to determine the genetic relatedness of Western Australian CA-MRSA clones within different multilocus sequence type (MLST) clonal clusters providing an insight into the frequency of S. aureus SCCmec acquisition within a region. Results The CA-MRSA population in Western Australia is genetically diverse consisting of 83 unique pulsed-field gel electrophoresis strains from which 46 MLSTs have been characterised. Forty five of these sequence types are from 18 MLST clonal clusters and two singletons. While SCCmec IV and V are the predominant SCCmec elements, SCCmec VIII and several novel and composite SCCmec elements are present. The emergence of MRSA in diverse S. aureus clonal clusters suggests horizontal transmission of the SCCmec element has occurred on multiple occasions. Furthermore DNA microarray and spa typing suggests horizontal transfer of SCCmec elements has also occurred within the same CC. For many single and double locus variant CA-MRSA clones only a few isolates have been detected. Conclusions Although multiple CA-MRSA clones have evolved in the Western Australian community only three clones have successfully adapted to the Western Australian community environment. These data suggest the successful evolution of a CA-MRSA clone may not only depend on the mobility of the SCCmec element but also on other genetic determinants. PMID:21955438

  13. 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

  14. Prevalence of Methicillin-resistant Staphylococcus pseudintermedius isolated from clinical samples of companion animals and equidaes.

    PubMed

    Ruscher, Claudia; Lübke-Becker, Antina; Wleklinski, Claus-G; Soba, Alexandra; Wieler, Lothar H; Walther, Birgit

    2009-04-14

    In this study the prevalence of Methicillin-resistant Staphylococcus pseudintermedius (MRSP) in clinical specimens of different animal species was defined by investigating a total of 16,103 clinical samples originating from veterinary facilities of five German federal states in 2007. Of all samples examined, 72 were positive for MRSP, giving an overall prevalence of 0.45%. In clinical specimens originating from small animals the prevalence was 0.58% (n=67; dogs n=61 and cats n=6), while samples from equidaes revealed a prevalence of 0.10% (n=5; horses n=4, donkey n=1). Forty-six representative phenotypically identified MRSP were further differentiated by DNA-based species assignment, PCR detection of mecA, SCCmec-typing and MIC determination. As expected, all 46 isolates were unambiguously proven to be MRSP by sequencing of housekeeping genes pta and cpn60 and being positive for mecA. Furthermore, all isolates harboured the mobile staphylococcal cassette chromosome mec (SCCmec) SCCmecIII. Antibiotic susceptibility testing for 20 different conventional antimicrobial agents disclosed a high rate of multidrug-resistant isolates (45 of 46) displaying an identical or at least similar resistance pattern for non-beta-lactam antimicrobials. The recognized prevalence of MRSP, which have already been shown to be potential zoonotic agents, reflects the recently emerging development of these serious and often multidrug-resistant pathogens in Germany.

  15. Tandem repeat sequence analysis of staphylococcal protein A (spa) gene in methicillin-resistant Staphylococcus pseudintermedius.

    PubMed

    Moodley, Arshnee; Stegger, Marc; Ben Zakour, Nouri L; Fitzgerald, J Ross; Guardabassi, Luca

    2009-03-30

    A putative staphylococcal protein A (spa) gene was discovered in the genome of Staphylococcus pseudintermedius and used for developing a species-specific spa typing protocol. Thirty-one clinical methicillin-resistant S. pseudintermedius (MRSP) isolates from dogs and cats in four countries were characterized by spa typing, pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome (SCCmec) typing. The results indicated the occurrence of two MRSP clones that acquired distinct SCCmec elements in Europe (t02, PFGE type A, SCCmec type III,) and California (t06, PFGE type B, SCCmec type V). Sequence analysis of mecA revealed the occurrence of four alleles (mecA1 to mecA4), which correlated with the geographical origin of the isolates and enabled discrimination of two distinct subtypes within the European clone. The newly developed spa typing method appeared to be a promising tool for easy and rapid typing of MRSP, either alone or in combination with SCCmec and mecA typing for fine-structure epidemiological analysis.

  16. Methicillin-Resistant Staphylococcus aureus Biofilms and Their Influence on Bacterial Adhesion and Cohesion

    PubMed Central

    Dakheel, Khulood Hamid; Abdul Rahim, Raha; Hun, Tan Geok

    2016-01-01

    Twenty-five methicillin-resistant Staphylococcus aureus (MRSA) isolates were characterized by staphylococcal protein A gene typing and the ability to form biofilms. The presence of exopolysaccharides, proteins, and extracellular DNA and RNA in biofilms was assessed by a dispersal assay. In addition, cell adhesion to surfaces and cell cohesion were evaluated using the packed-bead method and mechanical disruption, respectively. The predominant genotype was spa type t127 (22 out of 25 isolates); the majority of isolates were categorized as moderate biofilm producers. Twelve isolates displayed PIA-independent biofilm formation, while the remaining 13 isolates were PIA-dependent. Both groups showed strong dispersal in response to RNase and DNase digestion followed by proteinase K treatment. PIA-dependent biofilms showed variable dispersal after sodium metaperiodate treatment, whereas PIA-independent biofilms showed enhanced biofilm formation. There was no correlation between the extent of biofilm formation or biofilm components and the adhesion or cohesion abilities of the bacteria, but the efficiency of adherence to glass beads increased after biofilm depletion. In conclusion, nucleic acids and proteins formed the main components of the MRSA clone t127 biofilm matrix, and there seems to be an association between adhesion and cohesion in the biofilms tested. PMID:28078291

  17. Two cases of corneal ulcer due to methicillin-resistant Staphylococcus aureus in high risk groups.

    PubMed

    Lee, Kyung-Min; Lee, Hyun-Soo; Kim, Man-Soo

    2010-08-01

    Considering the popular use of antibiotic-containing eyedrops in Korea, it is important to know the emerging antibiotic-resistant strains of bacteria before treating infectious eye diseases. This is especially important in high-risk groups because of the high incidence of resistant infections and the subsequent treatment requirements. We report two cases of methicillin-resistant Staphylococcus aureus (MRSA) corneal ulcers in high-risk groups. The first case involved a patient who had keratitis after using antibiotic- and steroid-containing eyedrops to treat a corneal opacity that developed after repeated penetrating keratoplasty. The second case involved a patient who used antibiotic-containing eyedrops and a topical lubricant on a regular basis for >1 month to treat exposure keratitis due to lagophthalmos. The second patient's problems, which included a persistent superficial infiltration, developed after brain tumor surgery. Both cases showed MRSA on corneal culture, and the corneal ulcers improved in both patients after the application of vancomycin-containing eyedrops. In conclusion, MRSA infection should be considered in corneal ulcers that have a round shape, mild superficial infiltration, and slow progression, especially in high-risk groups. This report includes descriptions of the characteristic features, antibiotic sensitivities, prevention, and successful treatment with vancomycin-containing eyedrops for MRSA corneal ulcers.

  18. Methicillin-Resistant Staphylococcus aureus Carriage and Risk Factors for Skin Infections, Southwestern Alaska, USA

    PubMed Central

    Stevens, A. Michal; Baggett, Henry C.; Bruden, Dana; Parks, Debbie; Klejka, Joseph

    2010-01-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are common in southwestern Alaska. Outbreak strains have been shown to carry the genes for Panton-Valentine leukocidin (PVL). To determine if carriage of PVL-positive CA-MRSA increased the risk for subsequent soft tissue infection, we conducted a retrospective cohort study by reviewing the medical records of 316 persons for 3.6 years after their participation in a MRSA nasal colonization survey. Demographic, nasal carriage, and antimicrobial drug use data were analyzed for association with skin infection risk. Skin infections were more likely to develop in MRSA carriers than in methicillin-susceptible S. aureus carriers or noncarriers of S. aureus during the first follow-up year, but not in subsequent years. Repeated skin infections were more common among MRSA carriers. In an area where PVL-containing MRSA is prevalent, skin infection risk was increased among MRSA nasal carriers compared with methicillin-susceptible S. aureus carriers and noncarriers, but risk differential diminished over time. PMID:20409369

  19. Methicillin-Resistant Staphylococcus aureus Biofilms and Their Influence on Bacterial Adhesion and Cohesion.

    PubMed

    Dakheel, Khulood Hamid; Abdul Rahim, Raha; Neela, Vasantha Kumari; Al-Obaidi, Jameel R; Hun, Tan Geok; Yusoff, Khatijah

    2016-01-01

    Twenty-five methicillin-resistant Staphylococcus aureus (MRSA) isolates were characterized by staphylococcal protein A gene typing and the ability to form biofilms. The presence of exopolysaccharides, proteins, and extracellular DNA and RNA in biofilms was assessed by a dispersal assay. In addition, cell adhesion to surfaces and cell cohesion were evaluated using the packed-bead method and mechanical disruption, respectively. The predominant genotype was spa type t127 (22 out of 25 isolates); the majority of isolates were categorized as moderate biofilm producers. Twelve isolates displayed PIA-independent biofilm formation, while the remaining 13 isolates were PIA-dependent. Both groups showed strong dispersal in response to RNase and DNase digestion followed by proteinase K treatment. PIA-dependent biofilms showed variable dispersal after sodium metaperiodate treatment, whereas PIA-independent biofilms showed enhanced biofilm formation. There was no correlation between the extent of biofilm formation or biofilm components and the adhesion or cohesion abilities of the bacteria, but the efficiency of adherence to glass beads increased after biofilm depletion. In conclusion, nucleic acids and proteins formed the main components of the MRSA clone t127 biofilm matrix, and there seems to be an association between adhesion and cohesion in the biofilms tested.

  20. Clinical outcomes of osteomyelitis patients infected with methicillin-resistant Staphylococcus aureus USA-300 strains.

    PubMed

    Peyrani, P; Allen, M; Seligson, D; Roberts, C; Chen, A; Haque, N; Zervos, M; Wiemken, T; Harting, J; Christensen, D; Ramirez, R

    2012-03-01

    Methicillin-resistant Staphylococcus aureus (MRSA) USA-300 strains have emerged as an important cause of community-acquired infections. These strains have been recognized as an etiology of osteomyelitis but data on their incidence and outcomes are limited. We retrospectively studied the incidence and clinical outcomes of MRSA USA-300 osteomyelitis in patients at the University of Louisville Hospital and the Henry Ford Health System between January 2007 and March 2008. Pulsed-field gel electrophoresis was used to determine USA type. Clinical outcomes were defined as management success versus failure at 12 months. Chi-square tests, Fisher exact tests, and Mann-Whitney tests were used to compare patient characteristics on the basis of clinical outcomes and USA type. Of the 50 patients with MRSA osteomyelitis, 27 (54%) had the USA-300 strain. Clinical failure was identified in 22% (6/27) of the patients with MRSA USA-300 and in 30% (7/23) of the patients with MRSA non-USA-300 osteomyelitis (P = .509). Our results showed that MRSA USA-300 is a significant etiology of MRSA osteomyelitis. With current surgical and medical management, outcomes of patients with MRSA USA-300 osteomyelitis are similar to those of patients with MRSA non-USA-300 osteomyelitis.

  1. Eradication of carriage with methicillin-resistant Staphylococcus aureus: effectiveness of a national guideline.

    PubMed

    Ammerlaan, Heidi S M; Kluytmans, Jan A J W; Berkhout, Hanneke; Buiting, Anton; de Brauwer, Els I G B; van den Broek, Peterhans J; van Gelderen, Paula; Leenders, Sander A C A P; Ott, Alewijn; Richter, Clemens; Spanjaard, Lodewijk; Spijkerman, Ingrid J B; van Tiel, Frank H; Voorn, G Paul; Wulf, Mireille W H; van Zeijl, Jan; Troelstra, Annet; Bonten, Marc J M

    2011-10-01

    We evaluated the effectiveness of eradication of methicillin-resistant Staphylococcus aureus (MRSA) carriage in the Netherlands after the introduction of a guideline in 2006. The guideline distinguishes complicated (defined as the presence of MRSA infection, skin lesions, foreign-body material, mupirocin resistance and/or exclusive extranasal carriage) and uncomplicated carriage (not meeting criteria for complicated carriage). Mupirocin nasal ointment and chlorhexidine soap solution are recommended for uncomplicated carriers and the same treatment in combination with two oral antibiotics for complicated carriage. A prospective cohort study was performed in 18 Dutch centres from 1 October 2006 until 1 October 2008. Six hundred and thirteen MRSA carriers underwent one or more decolonization treatments during the study period, mostly after hospital discharge. Decolonization was achieved in 367 (60%) patients with one eradication attempt and ultimately 493 (80%) patients were decolonized, with a median time until decolonization of 10 days (interquartile range 7-43 days). Three hundred and twenty-seven (62%) carriers were treated according to the guideline, which was associated with an absolute increase in treatment success of 20% [from 45% (91/203) to 65% (214/327)]. Sixty percent of MRSA carriers were successfully decolonized after the first eradication attempt and 62% were treated according to the guideline, which was associated with an increased treatment success.

  2. Staphylococcal Enterotoxin P Predicts Bacteremia in Hospitalized Patients Colonized With Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Calderwood, Michael S.; Desjardins, Christopher A.; Sakoulas, George; Nicol, Robert; DuBois, Andrea; Delaney, Mary L.; Kleinman, Ken; Cosimi, Lisa A.; Feldgarden, Michael; Onderdonk, Andrew B.; Birren, Bruce W.; Platt, Richard; Huang, Susan S.

    2014-01-01

    Background. Methicillin-resistant Staphylococcus aureus (MRSA) colonization predicts later infection, with both host and pathogen determinants of invasive disease. Methods. This nested case-control study evaluates predictors of MRSA bacteremia in an 8–intensive care unit (ICU) prospective adult cohort from 1 September 2003 through 30 April 2005 with active MRSA surveillance and collection of ICU, post-ICU, and readmission MRSA isolates. We selected MRSA carriers who did (cases) and those who did not (controls) develop MRSA bacteremia. Generating assembled genome sequences, we evaluated 30 MRSA genes potentially associated with virulence and invasion. Using multivariable Cox proportional hazards regression, we assessed the association of these genes with MRSA bacteremia, controlling for host risk factors. Results. We collected 1578 MRSA isolates from 520 patients. We analyzed host and pathogen factors for 33 cases and 121 controls. Predictors of MRSA bacteremia included a diagnosis of cancer, presence of a central venous catheter, hyperglycemia (glucose level, >200 mg/dL), and infection with a MRSA strain carrying the gene for staphylococcal enterotoxin P (sep). Receipt of an anti-MRSA medication had a significant protective effect. Conclusions. In an analysis controlling for host factors, colonization with MRSA carrying sep increased the risk of MRSA bacteremia. Identification of risk-adjusted genetic determinants of virulence may help to improve prediction of invasive disease and suggest new targets for therapeutic intervention. PMID:24041793

  3. Avoiding the Perfect Storm: The Biologic and Clinical Case for Reevaluating the 7-Day Expectation for Methicillin-Resistant Staphylococcus aureus Bacteremia Before Switching Therapy

    PubMed Central

    Goldstein, Ellie J. C.; Kullar, Ravina; McKinnell, James A.; Sakoulas, George

    2014-01-01

    Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia (MRSAB) is associated with poor outcomes and serious complications. The MRSA guidelines define treatment failure and persistent bacteremia as lasting ≥7 days; however, this definition requires reevaluation. Aggressively reducing the bacterial inoculum promptly is critical because factors already in place before clinical presentation are driving resistance to the few antibiotics that are available to treat MRSAB. Alternative approaches to treat MRSAB should be considered within 3–4 days of persistent MRSAB. With rapid molecular diagnostics emerging in clinical microbiology laboratories and biomarkers as a potential for early patient risk stratification, a future shorter threshold may become possible. PMID:25048852

  4. Detection of Methicillin-Resistant Staphylococcus aureus by a Duplex Droplet Digital PCR Assay

    PubMed Central

    Kelley, KaShonda; Cosman, Angela; Belgrader, Phillip; Chapman, Brenda

    2013-01-01

    Health care-associated infections with methicillin-resistant Staphylococcus aureus (MRSA) contribute to significant hospitalization costs. We report here a droplet digital PCR (ddPCR) assay, which is a next-generation emulsion-based endpoint PCR assay for high-precision MRSA analysis. Reference cultures of MRSA, methicillin-susceptible S. aureus (MSSA), and confounders were included as controls. Copan swabs were used to sample cultures and collect specimens for analysis from patients at a large teaching hospital. Swab extraction and cell lysis were accomplished using magnetic-driven agitation of silica beads. Quantitative PCR (qPCR) (Roche Light Cycler 480) and ddPCR (Bio-Rad QX100 droplet digital PCR system) assays were used to detect genes for the staphylococcal protein SA0140 (SA) and the methicillin resistance (mecA) gene employing standard TaqMan chemistries. Both qPCR and ddPCR assays correctly identified culture controls for MRSA (76), MSSA (12), and confounder organisms (36) with 100% sensitivity and specificity. Analysis of the clinical samples (211 negative and 186 positive) collected during a study of MRSA nasal carriage allowed direct comparison of the qPCR and ddPCR assays to the Cepheid MRSA GeneXpert assay. A total of 397 clinical samples were examined in this study. Cepheid MRSA GeneXpert values were used to define negative and positive samples. Both the qPCR and ddPCR assays were in good agreement with the reference assay. The sensitivities for the qPCR and ddPCR assays were 96.8% (95% confidence interval [CI], 93.1 to 98.5%) and 96.8% (95% CI, 93.1 to 98.5%), respectively. Both the qPCR and ddPCR assays had specificities of 91.9% (95% CI, 87.5 to 94.9%) for qPCR and 91.0% (95% CI, 86.4 to 94.2%) for ddPCR technology. PMID:23596244

  5. Phenotypic and molecular characteristics of methicillin-resistant Staphylococcus aureus isolates from Ekiti State, Nigeria

    PubMed Central

    Olowe, Olugbenga Adekunle; Kukoyi, Olayinka Oluwatoyin; Taiwo, Samuel Sunday; Ojurongbe, Olusola; Opaleye, Oluyinka Oladele; Bolaji, Oloyede Samuel; Adegoke, Abiodun Adebimpe; Makanjuola, Olufunmilola Bamidele; Ogbolu, David Olusoga; Alli, Oyebode Terry

    2013-01-01

    Introduction The characteristics and antimicrobial resistance profiles of Staphylococcus aureus differs according to geographical regions and in relation to antibiotic usage. The aim of this study was to determine the biochemical characteristics of the prevalent S. aureus from Ekiti State, Nigeria, and to evaluate three commonly used disk diffusion methods (cefoxitin, oxacillin, and methicillin) for the detection of methicillin resistance in comparison with mecA gene detection by polymerase chain reaction. Materials and methods A total of 208 isolates of S. aureus recovered from clinical specimens were included in this study. Standard microbiological procedures were employed in isolating the strains. Susceptibility of each isolate to methicillin (5 μg), oxacillin (1 μg), and cefoxitin (30 μg) was carried out using the modified Kirby–Bauer/Clinical and Laboratory Standard Institute disk diffusion technique. They were also tested against panels of antibiotics including vancomycin. The conventional polymerase chain reaction method was used to detect the presence of the mecA gene. Results Phenotypic resistance to methicillin, oxacillin, and cefoxitin were 32.7%, 40.3%, and 46.5%, respectively. The mecA gene was detected in 40 isolates, giving a methicillin-resistant S. aureus (MRSA) prevalence of 19.2%. The S. aureus isolates were resistant to penicillin (82.7%) and tetracycline (65.4%), but largely susceptible to erythromycin (78.8% sensitive), pefloxacin (82.7%), and gentamicin (88.5%). When compared to the mecA gene as the gold standard for MRSA detection, methicillin, oxacillin, and cefoxitin gave sensitivity rates of 70%, 80%, and 100%, and specificity rates of 76.2%, 69.1%, and 78.5% respectively. Conclusion When compared with previous studies employing mecA polymerase chain reaction for MRSA detection, the prevalence of 19.2% reported in Ekiti State, Nigeria in this study is an indication of gradual rise in the prevalence of MRSA in Nigeria. A cefoxitin (30

  6. [Investigation of the virulence genes in methicillin-resistant Staphylococcus aureus strains isolated from biomaterial surfaces].

    PubMed

    Sudağidan, Mert; Cavuşoğlu, Cengiz; Bacakoğlu, Feza

    2008-01-01

    Staphylococci are the most important agents of nosocomial infections originating from biomaterials. The aim of this study was to investigate the presence of virulence genes and their phenotypic expressions in 11 methicillin-resistant Staphylococcus aureus strains isolated from the surfaces of clinically used biomaterials of 48 thorasic intensive-care unit patients. By the use of specific primers, the presence of genes encoding the attachment and biofilm production (icaA, icaC, bap), methicillin resistance (mecA), enterotoxins A-E (sea, seb, sec, sed, see), toxic shock syndrome toxin (tst), exfoliative toxins A and B (eta and etb), alpha- and beta-hemolysins (hla and hlb), staphylococcal exotoxin-like protein-1 (set1), proteases (sspA, sspB, aur, serine proteaz gene), lipase (geh) and the regulatory genes (sarA