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Sample records for acquired methicillin resistant

  1. 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

  2. Community-Acquired Methicillin-Resistant Pyogenic Liver Abscess

    PubMed Central

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

    2016-01-01

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

  3. 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…

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. Community-acquired methicillin-resistant Staphylococcus aureus in a Malaysian tertiary centre.

    PubMed

    Rashid, Zetti Zainol; Bahari, Norazlah; Othman, Amizah; Jaafar, Roslinda; Mohamed, Nurul Azmawati; Jabbari, Idimaz; Sulong, Anita; Hashim, Rohaidah; Ahmad, Norazah

    2013-01-01

    Abstract. Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a pathogen recognized to be distinct in both phenotype and genotype from hospital-acquired MRSA. We have identified CA-MRSA cases in Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia, including their antibiotic susceptibility patterns and genotypic characteristics. Cases were identified during January to December 2009 from routine clinical specimens, where culture and antibiotic susceptibility results yielded pauci-resistant MRSA isolates suspected as being CA-MRSA. The patients' clinical data were collected and their specimens were sent for molecular confirmation and analysis. Five cases of CA-MRSA were identified, which had a multi-sensitive pattern on antibiotic susceptibility tests and were resistant to only penicillin and oxacillin. All cases were skin and soft-tissue infections, including diabetic foot with gangrene, infected scalp hematoma, philtrum abscess in a healthcare worker, thrombophlebitis complicated with abscess and infected bedsore. All five cases were confirmed MRSA by detection of mecA. SCCmec typing (ccr and mec complex) revealed SCCmec type IV for all cases except the infected bedsore case. Panton-Valentine leukocidin gene was positive in all isolates. As clinical features among methicillin-sensitive Staphylococcus aureus, CA-MRSA and "nosocomial CA-MRSA" are indistinct, early recognition is necessary in order to initiate appropriate antibiotics and infection control measures. Continual surveillance of pauci-resistant MRSA and molecular analysis are necessary in order to identify emerging strains as well as their epidemiology and transmission, both in the community and in healthcare setting.

  9. Origin and Evolution of European Community-Acquired Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Wirth, Thierry; Andersen, Paal S.; Skov, Robert L.; De Grassi, Anna; Simões, Patricia Martins; Tristan, Anne; Petersen, Andreas; Aziz, Maliha; Kiil, Kristoffer; Cirković, Ivana; Udo, Edet E.; del Campo, Rosa; Vuopio-Varkila, Jaana; Ahmad, Norazah; Tokajian, Sima; Peters, Georg; Schaumburg, Frieder; Olsson-Liljequist, Barbro; Givskov, Michael; Driebe, Elizabeth E.; Vigh, Henrik E.; Shittu, Adebayo; Ramdani-Bougessa, Nadjia; Rasigade, Jean-Philippe; Price, Lance B.; Vandenesch, Francois; Larsen, Anders R.; Laurent, Frederic

    2014-01-01

    ABSTRACT Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) was recognized in Europe and worldwide in the late 1990s. Within a decade, several genetically and geographically distinct CA-MRSA lineages carrying the small SCCmec type IV and V genetic elements and the Panton-Valentine leukocidin (PVL) emerged around the world. In Europe, the predominant CA-MRSA strain belongs to clonal complex 80 (CC80) and is resistant to kanamycin/amikacin and fusidic acid. CC80 was first reported in 1993 but was relatively rare until the late 1990s. It has since been identified throughout North Africa, the Middle East, and Europe, with recent sporadic reports in sub-Saharan Africa. While strongly associated with skin and soft tissue infections, it is rarely found among asymptomatic carriers. Methicillin-sensitive S. aureus (MSSA) CC80 strains are extremely rare except in sub-Saharan Africa. In the current study, we applied whole-genome sequencing to a global collection of both MSSA and MRSA CC80 isolates. Phylogenetic analyses strongly suggest that the European epidemic CA-MRSA lineage is derived from a PVL-positive MSSA ancestor from sub-Saharan Africa. Moreover, the tree topology suggests a single acquisition of both the SCCmec element and a plasmid encoding the fusidic acid resistance determinant. Four canonical SNPs distinguish the derived CA-MRSA lineage and include a nonsynonymous mutation in accessory gene regulator C (agrC). These changes were associated with a star-like expansion into Europe, the Middle East, and North Africa in the early 1990s, including multiple cases of cross-continent imports likely driven by human migrations. PMID:25161186

  10. 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

  11. Effectiveness of various hospital-based solutions against community- acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Perona, Paul J; Johnson, Aaron J; Perona, John P; Issa, Kimona; Kapadia, Bhaveen H; Bonutti, Peter M; Mont, Michael A

    2013-01-01

    Periprosthetic infections with methicillin-resistant Staphylococcus aureus (MRSA) can be particularly burdensome and difficult to eradicate. One of the measures that infection control officers have emphasized in our hospitals has been the use of various hand sanitizers throughout the hospital. Our objective was to determine the level of growth inhibition of common hand sanitizers and surgical scrub solutions that are used to prevent the spread of community-acquired strains of MRSA. Various hospital and surgical agents (n = 13) were applied to community-acquired MRSA bacteria that had been cultured on agar plates. These different commercially available solutions were incubated for 48 h, and the plates were assessed to determine the level of growth inhibition (0, 25, 75, or 100%). The negative control was a test in which no agent was added to the MRSA culture, while a positive control tested 100% alcohol. Eight of the solutions tested had 100% growth inhibition, four solutions had partial growth inhibition effects, and one solution did not inhibit MRSA. Of the solutions with alcohol, the 62% solution did not kill MRSA, while the 80% solution only inhibited MRSA. Both the 95 and 100% alcohol solutions had 100% growth inhibition. Of the two surgical scrub solutions, only the one with iodine had 100% growth inhibition, whereas the solution with chloroxylenol (PCMX 3%) had only partial growth inhibition. This study suggests that the solutions with high levels of alcohol, chlorhexidine, or iodine appear to better kill MRSA and might best be used to prevent the spread of community-acquired MRSA in both the hospital and the surgical environment.

  12. Genomic analysis of ST88 community-acquired methicillin resistant Staphylococcus aureus in Ghana

    PubMed Central

    Buultjens, Andrew H.; Giulieri, Stefano; Owusu-Mireku, Evelyn; Aboagye, Samuel Y.; Baines, Sarah L.; Gonçalves da Silva, Anders; Howden, Benjamin P.; Pluschke, Gerd; Yeboah-Manu, Dorothy

    2017-01-01

    Background The emergence and evolution of community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) strains in Africa is poorly understood. However, one particular MRSA lineage called ST88, appears to be rapidly establishing itself as an “African” CA-MRSA clone. In this study, we employed whole genome sequencing to provide more information on the genetic background of ST88 CA-MRSA isolates from Ghana and to describe in detail ST88 CA-MRSA isolates in comparison with other MRSA lineages worldwide. Methods We first established a complete ST88 reference genome (AUS0325) using PacBio SMRT sequencing. We then used comparative genomics to assess relatedness among 17 ST88 CA-MRSA isolates recovered from patients attending Buruli ulcer treatment centres in Ghana, three non-African ST88s and 15 other MRSA lineages. Results We show that Ghanaian ST88 forms a discrete MRSA lineage (harbouring SCCmec-IV [2B]). Gene content analysis identified five distinct genomic regions enriched among ST88 isolates compared with the other S. aureus lineages. The Ghanaian ST88 isolates had only 658 core genome SNPs and there was no correlation between phylogeny and geography, suggesting the recent spread of this clone. The lineage was also resistant to multiple classes of antibiotics including β-lactams, tetracycline and chloramphenicol. Discussion This study reveals that S. aureus ST88-IV is a recently emerging and rapidly spreading CA-MRSA clone in Ghana. The study highlights the capacity of small snapshot genomic studies to provide actionable public health information in resource limited settings. To our knowledge this is the first genomic assessment of the ST88 CA-MRSA clone. PMID:28265515

  13. Panton-Valentine Leukocidin associated with community acquired methicillin resistant Staphylococcus aureus: a case report and review of interim guidelines.

    PubMed

    Baldwin, L N; Lowe, A D

    2008-07-01

    We report a case of community acquired methicillin resistant Staphylococcus aureus pneumonia. The causative organism was positive for the toxin Panton-Valentine Leukocidin. This resulted in a severe pneumonia requiring a prolonged stay on our intensive care unit. This infection is becoming more common in the United Kingdom. It can cause a far more aggressive illness than the hospital acquired infection with a high mortality if it becomes an invasive infection. The Department of Health has recently produced interim guidelines for its treatment which we have also reviewed.

  14. Ductus arteriosus aneurysm with community-acquired methicillin-resistant Staphylococcus aureus infection and spontaneous rupture: a potentially fatal quandary.

    PubMed

    Stewart, Audra; Dyamenahalli, Umesh; Greenberg, S Bruce; Drummond-Webb, Jonathan

    2006-06-01

    We present the case of a 6-month-old previously healthy girl who presented with high fever, labored breathing, and an enlarged cardiac silhouette on her chest radiograph. Comprehensive evaluation discovered a ductus arteriosus aneurysm and pericardial effusion with methicillin-resistant Staphylococcus aureus bacteremia. Despite pericardiocentesis and appropriate intravenous antibiotics, there was rapid enlargement of the aneurysm and accumulation of echogenic material within the ductus arteriosus aneurysm. Infected aneurysm rupture was identified during emergency surgery. This infant also had vocal cord paresis, a likely complication of the surgery. The clinical course, diagnosis, and treatment of this patient are discussed. Infection of a ductus arteriosus or an infected ductal arteriosus aneurysm is a rare and potentially fatal clinical entity. In the era of increasing community-acquired methicillin-resistant S aureus infections, this is a diagnosis that requires a high index of suspicion.

  15. Methicillin-resistant staphylococci.

    PubMed Central

    Chambers, H F

    1988-01-01

    Strains of staphylococci resistant to methicillin were identified immediately after introduction of this drug. Methicillin-resistant strains have unusual properties, the most notable of which is extreme variability in expression of the resistance trait. The conditions associated with this heterogeneous expression of resistance are described. Methicillin resistance is associated with production of a unique penicillin-binding protein (PBP), 2a, which is bound and inactivated only at high concentrations of beta-lactam antibiotics. PBP2a appears to be encoded by the mec determinant, which also is unique to methicillin-resistant strains. The relationships between PBP2a and expression of resistance and implications for the mechanism of resistance are discussed. The heterogeneous expression of methicillin resistance by staphylococci poses problems in the detection of resistant strains. Experience with several susceptibility test methods is reviewed and guidelines for performance of these tests are given. Treatment of infections caused by methicillin-resistant staphylococci is discussed. Vancomycin is the treatment of choice. Alternatives have been few because methicillin-resistant strains often are resistant to multiple antibiotics in addition to beta-lactam antibiotics. New agents which are active against methicillin-resistant staphylococci are becoming available, and their potential role in treatment is discussed. Images PMID:3069195

  16. Community-acquired necrotizing pneumonia caused by methicillin-resistant Staphylococcus aureus ST30-SCCmecIVc-spat019-PVL positive in San Antonio de Areco, Argentina.

    PubMed

    Fernandez, Silvina; Murzicato, Sofía; Sandoval, Orlando; Fernández-Canigia, Liliana; Mollerach, Marta

    2015-01-01

    Community-acquired methicillin-resistant Staphylococcus aureus is the first cause of skin and soft tissue infections, but can also produce severe diseases such as bacteremia, osteomyelitis and necrotizing pneumonia. Some S. aureus lineages have been described in cases of necrotizing pneumonia worldwide, usually in young, previously healthy patients. In this work, we describe a fatal case of necrotizing pneumonia due to community-acquired methicillin-resistant S. aureus clone ST30-SCCmecIVc-spat019-PVL positive in an immunocompetent adult patient.

  17. [Investigation of nasal carriage of community-acquired methicillin resistant Staphylococcus aureus in primary and high school students].

    PubMed

    Ozgüven, Atalay; Tünger, Ozlem; Cetin, Ciğdem Banu; Dinç, Gönül

    2008-10-01

    The aim of this study was to evaluate the carriage rate and risk factors of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) among the students in Manisa, Turkey. A total of 2015 students (1012 from the last phase of high schools and 1003 from the first phase of primary schools) were included in the study. None of the students had nasal MRSA carriage. Methicillin-sensitive S. aureus (MSSA) colonization rate was 14.7% (296/2015). Nasal carriage of MSSA was significantly higher in the primary school students (17.8%) than the high school students (11.6%) (p < 0.001). MSSA carriage was also higher in students of higher socioeconomical status than the students of lower status (p < 0.05). A statistically significant relationship was not determined between the nasal carriage and the risk factors (history of hospitalisation or surgical operation in the previous one year, use of antibiotics or history of skin/soft tissue infection in the last 6 months, presence of children < 15-years-old in the family, presence of healthcare workers in the same house, living in a crowded house). Penicillin and erythromycin resistance was found in 93.6% and 14.2% of MSSA strains, respectively. No resistance was detected against ciprofloxacin, co-trimoxazole, linezolid and vancomycin. There was a statistically significant difference between erythromycin resistance and antibiotic use within the last six months and the number of family members (p < 0.05). In conclusion, current treatment regimens still seem to be affective and safe for the empirical treatment of community-acquired S. aureus infections. Although CA-MRSA infections seem not to be a serious threat in our region yet, it is essential to carry out prevalence studies in the different populations of the community.

  18. Current role of community-acquired methicillin-resistant Staphylococcus aureus among children with skin and soft tissue infections.

    PubMed

    Teran, Carlos G; Sura, Sunitha; Mohamed, Tarek; Lin, Thant; Meadows, Marsha; Cynthia, Donkor; Wong, Sze H

    2012-01-02

    Community-acquired methicillin-resistant Staphylococcus aureus has become a well-established pathogen with alarming rates during the last decade. The current situation of this bacteria in pediatric infections is very limited and motivated us to conduct this study. This is a retrospective and analytical study including patients less than 18 years of age with the diagnosis of skin or soft tissue infections in 2008 and 2009 meeting the criteria of Community-acquired infection. A prevalence of 41.9% among skin and soft tissue infections was found. Inducible resistance to clindamycin was detected in 1.3% of the strains and the infection shows a seasonal predilection for summer (P=0.003); 57.8% of the cases required hospitalization with a mean stay of 3.3±2.5 days. The susceptibility to clindamycin and co-trimoxazole is 88 and 97% respectively. The resistance to erythromycin has reached 92%. The main diagnoses at presentation was gluteal abscess plus cellulitis (34.2%).The prevalence of CA-MRSA is trending up and seems to become a large burden for the health system in our community. Clindamycin is still an excellent option in the community setting since inducible clindamycin resistance is extremely low in this community. Co-trimoxazole should be kept as a reserved drug to avoid the rapid resurgence resistance in the community.

  19. Staphylococcal enterotoxin B toxic shock syndrome induced by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA).

    PubMed

    Kashiwada, Takeru; Kikuchi, Ken; Abe, Shinji; Kato, Hidehito; Hayashi, Hiroki; Morimoto, Taisuke; Kamio, Koichiro; Usuki, Jiro; Takeda, Shinhiro; Tanaka, Keiji; Imanishi, Ken'ichi; Yagi, Junji; Azuma, Arata; Gemma, Akihiko

    2012-01-01

    We herein report a case of toxic shock syndrome (TSS) associated with the 2009 pandemic H1N1 (pH1N1) influenza virus and a community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in a 16-year-old Vietnamese girl. Staphylococcal enterotoxin B (SEB) was detected in the patient's serum, and the level of anti-SEB antibodies was found to be elevated. A flow cytometric analysis showed evidence of activated SEB-reactive Vβ3+ and Vβ12+ T cells. These data suggest that the CA-MRSA-induced activation of SEB-reactive T cells may cause TSS in patients with pH1N1 virus infection. Moreover, this is the first report describing immunological confirmation of SEB contributing directly to TSS in a patient fulfilling the diagnostic criteria of TSS.

  20. Demography and Intercontinental Spread of the USA300 Community-Acquired Methicillin-Resistant Staphylococcus aureus Lineage

    PubMed Central

    Glaser, Philippe; Martins-Simões, Patrícia; Villain, Adrien; Barbier, Maxime; Tristan, Anne; Bouchier, Christiane; Ma, Laurence; Bes, Michele; Laurent, Frederic; Guillemot, Didier; Wirth, Thierry

    2016-01-01

    ABSTRACT Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) was recognized worldwide during the 1990s; in less than a decade, several genetically distinct CA-MRSA lineages carrying Panton-Valentine leukocidin genes have emerged on every continent. Most notably, in the United States, the sequence type 18-IV (ST8-IV) clone known as USA300 has become highly prevalent, outcompeting methicillin-susceptible S. aureus (MSSA) and other MRSA strains in both community and hospital settings. CA-MRSA bacteria are much less prevalent in Europe, where the European ST80-IV European CA-MRSA clone, USA300 CA-MRSA strains, and other lineages, such as ST22-IV, coexist. The question that arises is whether the USA300 CA-MRSA present in Europe (i) was imported once or on very few occasions, followed by a broad geographic spread, anticipating an increased prevalence in the future, or (ii) derived from multiple importations with limited spreading success. In the present study, we applied whole-genome sequencing to a collection of French USA300 CA-MRSA strains responsible for sporadic cases and micro-outbreaks over the past decade and United States ST8 MSSA and MRSA isolates. Genome-wide phylogenetic analysis demonstrated that the population structure of the French isolates is the product of multiple introductions dating back to the onset of the USA300 CA-MRSA clone in North America. Coalescent-based demography of the USA300 lineage shows that a strong expansion occurred during the 1990s concomitant with the acquisition of the arginine catabolic mobile element and antibiotic resistance, followed by a sharp decline initiated around 2008, reminiscent of the rise-and-fall pattern previously observed in the ST80 lineage. A future expansion of the USA300 lineage in Europe is therefore very unlikely. PMID:26884428

  1. Acute haematogenous community-acquired methicillin-resistant Staphylococcus aureus osteomyelitis in an adult: Case report and review of literature

    PubMed Central

    2012-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) has of late emerged as a cause of community-acquired infections among immunocompetent adults without risk factors. Skin and soft tissue infections represent the majority of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clinical presentations, whilst invasive and life-threatening illness like necrotizing pneumonia, necrotizing fasciitis, pyomyositis, osteomyelitis and sepsis syndrome are less common. Although more widely described in the pediatric age group, the occurrence of CA-MRSA osteomyelitis in adults is an uncommonly reported entity. Case presentation We describe an invasive CA-MRSA infection in a 28 year-old previously healthy male, manifesting with bacteraemia, osteomyelitis of femur, pyomyositis and septic arthritis of the knee. Initially a preliminary diagnosis of osteosarcoma was suggested by imaging studies and patient underwent a bone biopsy. MRSA was subsequently isolated from blood cultures taken on day of admission, bone, tissue and pus cultures. Incision and drainage of abscess was performed and patient was treated with vancomycin, with fusidic acid added later. It took 6 months for the inflammatory markers to normalize, warranting 6-months of anti-MRSA therapy. Patient was a fervent deer hunter and we speculate that he acquired this infection from extensive direct contact with deer. Molecular characterization of this isolate showed that it belonged to multilocus sequence type (MLST) ST30 and exhibited the staphylococcal chromosome cassette mec (SCCmec) type IV, staphylococcus protein A (spa) type t019, accessory gene regulator (agr) type III and dru type dt10m. This strain harbored Panton-Valentine leukocidin (pvl) genes together with 3 other virulent genes; sei (enterotoxin), hlg (hemolysin) and fnbA (fibronectin binding protein). Conclusion This case study alerts physicians that beyond the most commonly encountered skin and soft tissue infections, pvl

  2. Clinical and molecular epidemiology of community-acquired, healthcare-associated and nosocomial methicillin-resistant Staphylococus aureus in Spain.

    PubMed

    Rodríguez-Baño, J; Angeles Domínguez, M; Blas Millán, A; Borraz, C; Pau González, M; Almirante, B; Cercenado, E; Padilla, B; Pujol, M

    2009-12-01

    A prospective cohort study including all new cases of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection in 64 Spanish hospitals during June 2003 was performed to investigate the epidemiology of MRSA in Spain. Only patients who yielded clinical MRSA-positive samples were included. Epidemiological and clinical data for a total of 370 cases were collected. Genotyping was performed using pulsed-field gel electrophoresis and multilocus sequence typing. Panton-Valentine leukocidin genes and the staphylococcal chromosomal cassette mec (SCCmec) were identified in representative isolates. MRSA was considered to be nosocomially acquired in 202 cases (55%), healthcare-associated (HCA) in 139 cases (38%), community-acquired (CA) in three cases, and of uncertain mode of acquisition in 26 (7%) cases. The pooled population-based rate was 2.31 cases/100,000 population/month, and the pooled nosocomial rate was 0.21 cases/1000 hospital stays (20.2% of S. aureus). Peripheral vascular disease, respiratory tract infections, catheter infections, bloodstream infections and crude mortality were more frequent among HCA cases, whereas neoplasia and urinary tract infections were more frequent among nosocomially acquired cases. Two clones related to the paediatric clone ST5-IV accounted for 71% of the isolates; EMRSA-16 has emerged in two different geographical areas. Only one isolate belonged to the formerly predominant Iberian clone. The three CA isolates were related to the USA300 clone. SCCmec type IV was the most frequent type in nosocomial and HCA isolates. The epidemiology of MRSA has changed in Spain; outpatients with previous healthcare contact represent a very important reservoir of MRSA, and community isolates are emerging.

  3. A case of familial transmission of community-acquired methicillin-resistant Staphylococcus aureus carrying the Inu(A) gene in Santa Fe city, Argentina.

    PubMed

    Méndez, Emilce de Los A; Roldán, María L; Baroni, María R; Mendosa, María A; Cristóbal, Sabrina A; Virgolini, Stella M; Faccone, Diego

    2012-01-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is increasingly recognized as an important pathogen causing skin and soft tissue infections as well as necrotizing pneumonia. We describe a case of familial transmission of CA-MRSA between a 6-month-old boy and his mother in Santa Fe City, Argentina. Both isolates showed an identical antimicrobial susceptibility profile, carried type IV SCCmec and harboured the pvl and the lnu(A) genes. Isolates showed indistinguishable SmaI-PFGE patterns confirming their genetic relationship. These results corroborate the intrafamilial transmission of CA-MRSA and might associate this strain with the repetitive events of furunculosis within the family.

  4. The skin in the gym: a comprehensive review of the cutaneous manifestations of community-acquired methicillin-resistant Staphylococcus aureus infection in athletes.

    PubMed

    Cohen, Philip R

    2008-01-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CAMRSA) infection is currently a problem of epidemic proportion. Athletes represent a specific group of individuals who are at increased risk to develop CAMRSA skin infections. In this article, the previously published reports of cutaneous CAMRSA infections in athletes are categorized by sport and summarized. General treatment guidelines for the management of cutaneous CAMRSA infection and its associated lesions in athletes are discussed. Also, recommendations for the prevention of CAMRSA skin infection in sports participants are reviewed.

  5. Microbiology of skin and soft tissue infections in the age of community-acquired methicillin-resistant Staphylococcus aureus.

    PubMed

    Ray, G Thomas; Suaya, Jose A; Baxter, Roger

    2013-05-01

    The objectives of this study were to determine the etiology of skin and soft-tissue infections (SSTIs) in a general population, and to describe patient characteristics, SSTI types, frequency of microbiologic testing, and the role of methicillin-resistant Staphylococcus aureus (MRSA) over time. Using electronic databases, we identified SSTI episodes and microbiologic testing among members of a large US health plan. Between 2006 and 2009, 648699 SSTI episodes were identified, of which 23% had a specimen, of which 15% were blood. A pathogen was identified in 58% of SSTI cultures. S. aureus was the most common pathogen (80% of positive cultures). Half of S. aureus isolates were MRSA. Among cellulitis and abscess episodes with a positive blood culture, 21% were methicillin-sensitive S. aureus, 16% were MRSA, 21% were beta-hemolytic streptococci and 28% were Gram negative bacteria. Between 1998 and 2009, the percentage of SSTIs for which a culture was obtained increased from 11% to 24%. In SSTI episodes with a culture-confirmed pathogen, MRSA increased from 5% in 1998 to 9% in 2001 to 42% in 2005, decreasing to 37% in 2009. These data can inform the choice of antibiotics for treatment of SSTIs.

  6. Comparative genomics of community-acquired ST59 methicillin-resistant Staphylococcus aureus in Taiwan: novel mobile resistance structures with IS1216V.

    PubMed

    Hung, Wei-Chun; Takano, Tomomi; Higuchi, Wataru; Iwao, Yasuhisa; Khokhlova, Olga; Teng, Lee-Jene; Yamamoto, Tatsuo

    2012-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) with ST59/SCCmecV and Panton-Valentine leukocidin gene is a major community-acquired MRSA (CA-MRSA) lineage in Taiwan and has been multidrug-resistant since its initial isolation. In this study, we studied the acquisition mechanism of multidrug resistance in an ST59 CA-MRSA strain (PM1) by comparative genomics. PM1's non-β-lactam resistance was encoded by two unique genetic traits. One was a 21,832-bp composite mobile element structure (MES(PM1)), which was flanked by direct repeats of enterococcal IS1216V and was inserted into the chromosomal sasK gene; the target sequence (att) was 8 bp long and was duplicated at both ends of MES(PM1). MES(PM1) consisted of two regions: the 5'-end side 12.4-kb region carrying Tn551 (with ermB) and Tn5405-like (with aph[3']-IIIa and aadE), similar to an Enterococcus faecalis plasmid, and the 3'-end side 6,587-bp region (MES(cat)) that carries cat and is flanked by inverted repeats of IS1216V. MES(cat) possessed att duplication at both ends and additional two copies of IS1216V inside. MES(PM1) represents the first enterococcal IS1216V-mediated composite transposon emerged in MRSA. IS1216V-mediated deletion likely occurred in IS1216V-rich MES(PM1), resulting in distinct resistance patterns in PM1-derivative strains. Another structure was a 6,025-bp tet-carrying element (MES(tet)) on a 25,961-bp novel mosaic penicillinase plasmid (pPM1); MES(tet) was flanked by direct repeats of IS431, but with no target sequence repeats. Moreover, the PM1 genome was deficient in a copy of the restriction and modification genes (hsdM and hsdS), which might have contributed to the acquisition of enterococcal multidrug resistance.

  7. Invasive Community-Acquired Methicillin-Resistant Staphylococcus aureus in a Japanese Girl with Disseminating Multiple Organ Infection: A Case Report and Review of Japanese Pediatric Cases

    PubMed Central

    Yonezawa, Ryuta; Kuwana, Tsukasa; Kawamura, Kengo; Inamo, Yasuji

    2015-01-01

    Pediatric invasive community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection is very serious and occasionally fatal. This infectious disease is still a relatively rare and unfamiliar infectious disease in Japan. We report a positive outcome in a 23-month-old Japanese girl with meningitis, osteomyelitis, fasciitis, necrotizing pneumonia, urinary tract infection, and bacteremia due to CA-MRSA treated with linezolid. PCR testing of the CA-MRSA strain was positive for PVL and staphylococcal enterotoxin b and negative for ACME. SCC mec was type IVa. This case underscores the selection of effective combinations of antimicrobial agents for its treatment. We need to be aware of invasive CA-MRSA infection, which rapidly progresses with a serious clinical course, because the incidence of the disease may be increasing in Japan. PMID:26819794

  8. Community-acquired methicillin-resistant Staphylococcus aureus: skin infection presenting as an axillary abscess with cellulitis in a college athlete.

    PubMed

    Cohen, Philip R

    2005-01-01

    A healthy 19-year-old black man without any methicillin-resistant Staphylococcus aureus risk factors developed axillary boils after he began lifting weights at the university gym in Houston, TX. He presented with a large tender erythematous fluctuant abscess of his right axillae and a superiorly located smaller painful red indurated nodule; the surrounding cellulitis extended into the adjacent tissue (Figure). The abscess was incised, drained, and cultured. Empiric treatment with cephalexin 500 mg q.i.d. was given for 7 days. The culture grew methicillin-resistant S. aureus. Susceptibility testing of the S. aureus isolate was performed by Laboratory Corp. of America (Houston, TX); the Vitek system (Biomerieux, Hazelwood, MO) was used, and the specimen was incubated for 8 hours. Confirmation of methicillin resistance was performed using a methicillin-resistant S. aureus plate and the specimen was incubated for 24 hours. In addition to resistance to methicillin, the bacterial isolate was also resistant to ciprofloxacin, erythromycin, and penicillin. The S. aureus strain had intermediate susceptibility to levofloxacin and was susceptible to clindamycin, gentamicin, rifampin, tetracycline, trimethoprim/sulfamethoxazole, and vancomycin. The infection persisted and the antibiotic was changed to double strength trimethoprim/sulfamethoxazole, taken twice daily for 15 days. In addition, topical care included lesional and intranasal application of mupirocin 2% ointment and daily cleaning of the area with 10% povidone-iodine liquid soap. The skin infection completely resolved without recurrence within 2 weeks.

  9. Molecular characteristics of community-acquired methicillin-resistant Staphylococcus aureus strains isolated from outpatients with skin and soft tissue infections in Wuhan, China.

    PubMed

    Liu, Xiaoli; Liang, Jiansheng; Jiang, Yuanshan; Wang, Bin; Yuan, Hong; Zhang, Lihua; Zhou, Yanfei; Xu, Huiqiong; Zhou, Wang

    2016-06-01

    This study aims to investigate the antimicrobial susceptibility, molecular characteristics and virulence genes of community-acquired methicillin-resistant ITALIC! Staphylococcus aureus(CA-MRSA) isolates with skin and soft tissue infections (SSTIs). Outpatients with SSTIs visiting five medical and health institutions were enrolled from 2011 to 2013. Available ITALIC! S. aureus isolates were characterized by antimicrobial susceptibility testing, and detection of PVL genes. For CA-MRSA isolates, we performed typing of staphylococcal cassette chromosome ITALIC! mec(SCC ITALIC! mec), multi locus sequence typing (MLST) and carriage of 27 virulence genes. A total of 203 ITALIC! S. aureusstrains were isolated from 1400 outpatients with SSTIs, and 21 (10.3%) were CA-MRSA isolates. The positive rate of PVL genes among ITALIC! S. aureus, CA-MRSA and methicillin-susceptible ITALIC! S. aureus(MSSA) isolates were 39.4%, 71.4% and 35.7%, respectively. CA-MRSA strains had greater sensitivity to non-β-lactam antimicrobial agents. All CA-MRSA isolates belonged to SCC ITALIC! mecIV and V, accounting for 47.6% and 52.4%, respectively. ST59 was the most common lineage accounting for 76.2%; ST59-SCC ITALIC! mecIVa-PVL-positive clone was found to be the predominant clone, accounting for 38.1%. All CA-MRSA isolates were found to be positive for one or more virulence genes, 28.6% of isolates carried PVL, ITALIC! seb, ITALIC! sek, ITALIC! seq, ITALIC! hla, ITALIC! hlb, ITALIC! hldand ITALIC! hlg-2. CA-MRSA infections were relatively uncommon in outpatients with SSTIs, but they carried many virulence genes, ST59-SCC ITALIC! mecIV a-PVL-positive clone was the predominant clone in Wuhan, China.

  10. Clinical aspects of infection with methicillin-resistant Staphylococcus aureus USA300 strain, generally regarded as community-acquired, in Japan.

    PubMed

    Nakamura, Itaru; Yamaguchi, Tetsuo; Miura, Yuri; Shimizu, Hiroyuki; Fukushima, Shinji; Mizuno, Yasutaka; Matsumoto, Tetsuya

    2013-01-01

    The characteristics of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in Japan have not yet been completely established compared with those in Europe and the United States. CA-MRSA infections with the USA300 clone are very rare in Japan. In this study, we describe 4 cases of CA-MRSA infections, particularly the USA300 clone. Case 1 involved a 21-year-old man without any remarkable medical history or risk factors of CA-MRSA who suffered from a rapidly progressive infection in his left arm. Case 2 involved a 34-year-old man and Case 3 a 22-year-old man who presented with recurrent and refractory furuncles. Both men were members of a combat sports gym where other members also had skin infections. Case 4 involved a 60-year-old man with lumbar canal stenosis who suffered from surgical site infection 7 days after lumbar laminectomy and posterolateral fusion. Only 5 cases of USA300 infections were reported in Japan from 2007 to 2009, and 4 cases were detected at Tokyo Medical University Hospital from 2010 to 2011. The diversity of the routes of infection in these cases may indicate the possible spread of the USA300 clone in Japan.

  11. Prevalence, Antibiogram and Molecular Characterization of Comunity-Acquired Methicillin-Resistant Staphylococcus Aureus in AWKA, Anambra Nigeria

    PubMed Central

    Ike, Blessing; Ugwu, Malachy C.; Ikegbunam, Moses N.; Nwobodo, David; Ejikeugwu, Chika; Gugu, Thaddeus; Esimone, Charles O.

    2016-01-01

    Objectives: This study evaluated the prevalence, antibiogram and molecular features of CA-MRSA in Awka, Nigeria. Methods: Confirmation of MRSA was done by testing resistance to oxacillin (1µg), cloxacillin (5µg) and cefoxitin (30µg) on sterile Mueller Hinton agar supplemented with 4% sodium chloride. The MRSA strains were subjected to antimicrobial susceptibility testing using Kirby-Bauer disc diffusion method. Minimum inhibitory concentration was determined using agar dilution method. Penicillin binding protein 2a was detected through rapid latex agglutination assay while mecA gene was detected by polymerase chain reaction. A total of 142 S. aureus isolates were obtained from 261 samples sourced from Staff, students and fomites of the Faculty of Pharmaceutical Sciences Result: The overall prevalence of MRSA was 22.6%. The carriage rate was higher in females (56.5%) than male (43.5%) and was highest in individuals of 20-30 years of age (57.65%). The MIC of the oxacillin sodium salt ranged from 4-32 μg/ml. The multi-antibiotic resistance indices show that 53.4% had Multiple Antibiotic Resistance Indexing (MARI) higher than 0.2. Penicillin binding protein 2a was detected in 8.4% of MRSA isolates, all from nasal carriage while mecA gene was detected in 5 of isolates. Conclusion: This study showed a very high prevalence of MRSA carriage among studied subjects. PMID:28217194

  12. In vivo bioluminescence imaging to evaluate systemic and topical antibiotics against community-acquired methicillin-resistant Staphylococcus aureus-infected skin wounds in mice.

    PubMed

    Guo, Yi; Ramos, Romela Irene; Cho, John S; Donegan, Niles P; Cheung, Ambrose L; Miller, Lloyd S

    2013-02-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) frequently causes skin and soft tissue infections, including impetigo, cellulitis, folliculitis, and infected wounds and ulcers. Uncomplicated CA-MRSA skin infections are typically managed in an outpatient setting with oral and topical antibiotics and/or incision and drainage, whereas complicated skin infections often require hospitalization, intravenous antibiotics, and sometimes surgery. The aim of this study was to develop a mouse model of CA-MRSA wound infection to compare the efficacy of commonly used systemic and topical antibiotics. A bioluminescent USA300 CA-MRSA strain was inoculated into full-thickness scalpel wounds on the backs of mice and digital photography/image analysis and in vivo bioluminescence imaging were used to measure wound healing and the bacterial burden. Subcutaneous vancomycin, daptomycin, and linezolid similarly reduced the lesion sizes and bacterial burden. Oral linezolid, clindamycin, and doxycycline all decreased the lesion sizes and bacterial burden. Oral trimethoprim-sulfamethoxazole decreased the bacterial burden but did not decrease the lesion size. Topical mupirocin and retapamulin ointments both reduced the bacterial burden. However, the petrolatum vehicle ointment for retapamulin, but not the polyethylene glycol vehicle ointment for mupirocin, promoted wound healing and initially increased the bacterial burden. Finally, in type 2 diabetic mice, subcutaneous linezolid and daptomycin had the most rapid therapeutic effect compared with vancomycin. Taken together, this mouse model of CA-MRSA wound infection, which utilizes in vivo bioluminescence imaging to monitor the bacterial burden, represents an alternative method to evaluate the preclinical in vivo efficacy of systemic and topical antimicrobial agents.

  13. In Vivo Bioluminescence Imaging To Evaluate Systemic and Topical Antibiotics against Community-Acquired Methicillin-Resistant Staphylococcus aureus-Infected Skin Wounds in Mice

    PubMed Central

    Guo, Yi; Ramos, Romela Irene; Cho, John S.; Donegan, Niles P.; Cheung, Ambrose L.

    2013-01-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) frequently causes skin and soft tissue infections, including impetigo, cellulitis, folliculitis, and infected wounds and ulcers. Uncomplicated CA-MRSA skin infections are typically managed in an outpatient setting with oral and topical antibiotics and/or incision and drainage, whereas complicated skin infections often require hospitalization, intravenous antibiotics, and sometimes surgery. The aim of this study was to develop a mouse model of CA-MRSA wound infection to compare the efficacy of commonly used systemic and topical antibiotics. A bioluminescent USA300 CA-MRSA strain was inoculated into full-thickness scalpel wounds on the backs of mice and digital photography/image analysis and in vivo bioluminescence imaging were used to measure wound healing and the bacterial burden. Subcutaneous vancomycin, daptomycin, and linezolid similarly reduced the lesion sizes and bacterial burden. Oral linezolid, clindamycin, and doxycycline all decreased the lesion sizes and bacterial burden. Oral trimethoprim-sulfamethoxazole decreased the bacterial burden but did not decrease the lesion size. Topical mupirocin and retapamulin ointments both reduced the bacterial burden. However, the petrolatum vehicle ointment for retapamulin, but not the polyethylene glycol vehicle ointment for mupirocin, promoted wound healing and initially increased the bacterial burden. Finally, in type 2 diabetic mice, subcutaneous linezolid and daptomycin had the most rapid therapeutic effect compared with vancomycin. Taken together, this mouse model of CA-MRSA wound infection, which utilizes in vivo bioluminescence imaging to monitor the bacterial burden, represents an alternative method to evaluate the preclinical in vivo efficacy of systemic and topical antimicrobial agents. PMID:23208713

  14. 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.

  15. THE FREQUENCY OF COMMUNITY-ACQUIRED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (CA-MRSA) AMONG SAMPLES IN INSTITUTE FOR PUBLIC HEALTH IN CANTON SARAJEVO

    PubMed Central

    Bektas, Sabaheta; Obradovic, Amina; Aljicevic, Mufida; Numanovic, Fatima; Hodzic, Dunja; Sporisevic, Lutvo

    2016-01-01

    Background: The increase in the incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections lacking risk factors for exposure to the health care system has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). These strains have been distinguished from health care-associated MRSA (HA-MRSA) strains by epidemiological, molecular and genetic means as well as by antibiotic susceptibility profile, tissue tropism and virulence traits. Objective: To assess prevalence and antibiotic susceptibility profile of CA-MRSA in Canton Sarajevo, Bosnia and Herzegovina. Results: Out of 1.905 positive Staphylococcus aureus isolates from various samples of outpatients collected during six months, 279 (14,64%) were MRSA isolates. Out of 279 MRSA samples, 133 (47,67%) were found in nasal swabs, from which 48 (36,09%) were in the age group <1 year and 39 (29,32 %) are in the age 1-5 year. Rate of the positive skin swabs was highest among the subject of age group <1 year (46 or 54,12 %) and 1-5 year (18 or 21,18 %). Predominantly antibiotic types among MRSA strains are resistant to penicillin and cefoxitin (36,90 %) and to penicillin, cefoxitin and erythromycin (61,35 %). Conclusion: Continued monitoring of epidemiology and emerging drug resistance data is critical for the effective management of these infections. PMID:27047271

  16. Application of monoclonal antibodies generated against Panton-Valentine Leukocidin (PVL-S) toxin for specific identification of community acquired methicillin resistance Staphylococcus aureus.

    PubMed

    Poojary, Niveditha Sundar; Ramlal, Shylaja; Urs, Radhika Madan; Sripathy, Murali Harishchandra; Batra, Harsh Vardhan

    2014-12-01

    Panton-Valentine Leukocidin (PVL) produced by community acquired methicillin Staphylococcus aureus (CA-MRSA) involved in skin and soft-tissue infections and necrotizing pneumonia comprised of two fractions, namely PVL S and PVL F. In the present study, three monoclonal antibodies designated as MAb1, MAb9 and MAb10 were generated against recombinant PVL-S (35kDa) protein of S. aureus. All the three MAbs specifically reacted to confirm PVL-S positive strains of S. aureus recovered from clinical samples in Western blot analysis. Similarly all the three MAbs did not show any binding to other tested 14 different pathogenic bacteria belonging to other genera and species in Western blot analysis. Furthermore, a simple dot-ELISA method was standardized for the identification of PVL-S toxin containing S. aureus strains. Initially in dot-ELISA, Protein A (Spa) of S. aureus posed background noise problems due to the non-specific binding of antibodies resulting in false positive reactions. With the addition of 10mM diethylpyrocarbonate (DEPC) along with 5% milk in PBS in the blocking step prevented this non-specific binding of Spa to mouse anti-PVL monoclonal antibodies in dot-ELISA. Once standardized, this simple dot-ELISA was evaluated with nine PVL positive strains recovered from food, environmental and clinical samples and the results were compared with PCR assay for the presence of PVL toxin genes and also with Western blot analysis. A 100% correlation was found between dot-ELISA, PCR assay and Western blot analysis. Collectively our results suggest the newly developed simple dot-ELISA system can be of immense help in providing, rapid detection of the PVL toxin containing S. aureus strains at a relatively low cost and will be a valuable tool for the reliable identification of CA-MRSA.

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

    PubMed

    Geria, Aanand N; Schwartz, Robert A

    2010-02-01

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

  18. 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.

  19. 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.

  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-Susceptible, Vancomycin-Resistant Staphylococcus aureus, Brazil.

    PubMed

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

    2015-10-01

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

  2. Methicillin-resistant staphylococci isolated from animals.

    PubMed

    van Duijkeren, E; Box, A T A; Heck, M E O C; Wannet, W J B; Fluit, A C

    2004-10-05

    Staphylococci isolated from animals (n=311) were screened for methicillin resistance by oxacillin agar screening. Oxacillin-resistant strains were tested for the presence of the mecA gene by PCR. Isolates were identified by standard techniques and 16S rDNA analysis, and their antimicrobial susceptibilities were tested using an agar diffusion method. MecA-positive strains were further analyzed using pulsed-field gel electrophoresis (PFGE). From 11 multidrug-resistant staphylococci, 6 were mecA-positive: 2 methicillin-resistant Staphylococcus aureus (MRSA) and 4 Staphylococcus haemolyticus. Screening of 300 staphylococci (100 S. aureus, 100 S. intermedius and 100 coagulase-negative staphylococci (CNS)) randomly chosen from the strain collection of the Veterinary Microbiological Diagnostic Center yielded five oxacillin-resistant coagulase-negative staphylococci, four of which were mecA-positive. PFGE showed that all mecA-positive staphylococci isolated from animals had distinct patterns. However, one MRSA isolated from a flank fistula of a dog showed homology to a human epidemic MRSA cluster, suggesting that transfer of MRSA between humans and dogs might occur.

  3. Lifestyle-Associated Risk Factors for Community-Acquired Methicillin-Resistant Staphylococcus aureus Carriage in the Netherlands: An Exploratory Hospital-Based Case-Control Study

    PubMed Central

    van Rijen, Miranda M. L.; Kluytmans-van den Bergh, Marjolein F. Q.; Verkade, Erwin J. M.; ten Ham, Peter B. G.; Feingold, Beth J.; Kluytmans, Jan A. J. W.

    2013-01-01

    Background Community-acquired MRSA (CA-MRSA) is rapidly increasing. Currently, it is unknown which reservoirs are involved. An exploratory hospital-based case-control study was performed in sixteen Dutch hospitals to identify risk factors for CA-MRSA carriage in patients not belonging to established risk groups. Methods Cases were in- or outpatients from sixteen Dutch hospitals, colonised or infected with MRSA without healthcare- or livestock-associated risk factors for MRSA carriage. Control subjects were patients not carrying MRSA, and hospitalised on the same ward or visited the same outpatients' clinic as the case. The presence of potential risk factors for CA-MRSA carriage was determined using a standardised questionnaire. Results Regular consumption of poultry (OR 2⋅40; 95% CI 1⋅08–5⋅33), cattle density per municipality (OR 1⋅30; 95% CI 1⋅00–1⋅70), and sharing of scuba diving equipment (OR 2⋅93 95% CI 1⋅19–7⋅21) were found to be independently associated with CA-MRSA carriage. CA-MRSA carriage was not related to being of foreign origin. Conclusions The observed association between the consumption of poultry and CA-MRSA carriage suggests that MRSA in the food chain may be a source for MRSA carriage in humans. Although sharing of scuba diving equipment was found to be associated with CA-MRSA carriage, the role played by skin abrasions in divers, the lack of decontamination of diving materials, or the favourable high salt content of sea water is currently unclear. The risk for MRSA MC398 carriage in areas with a high cattle density may be due to environmental contamination with MRSA MC398 or human-to-human transmission. Further studies are warranted to confirm our findings and to determine the absolute risks of MRSA acquisition associated with the factors identified. PMID:23840344

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Discrimination between methicillin-resistant and methicillin-susceptible Staphylococcus aureus using pyrolysis mass spectrometry and artificial neural networks.

    PubMed

    Goodacre, R; Rooney, P J; Kell, D B

    1998-01-01

    Curie-point pyrolysis mass spectra were obtained from 15 methicillin-resistant and 22 methicillin-susceptible Staphylococcus aureus strains. Cluster analysis showed that the major source of variation between the pyrolysis mass spectra resulted from the phage group of the bacteria, not their resistance or susceptibility to methicillin. By contrast, artificial neural networks could be trained to recognize those aspects of the pyrolysis mass spectra that differentiated methicillin-resistant from methicillin-sensitive strains. The trained neural network could then use pyrolysis mass spectral data to assess whether an unknown strain was resistant to methicillin. These results give the first demonstration that the combination of pyrolysis mass spectrometry with neural networks can provide a very rapid and accurate antibiotic susceptibility testing technique.

  13. 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

  14. Missense Mutations in PBP2A Affecting Ceftaroline Susceptibility Detected in Epidemic Hospital-Acquired Methicillin-Resistant Staphylococcus aureus Clonotypes ST228 and ST247 in Western Switzerland Archived since 1998

    PubMed Central

    Kelley, William L.; Jousselin, Ambre; Barras, Christine; Lelong, Emmanuelle

    2015-01-01

    The development and maintenance of an arsenal of antibiotics is a major health care challenge. Ceftaroline is a new cephalosporin with activity against methicillin-resistant Staphylococcus aureus (MRSA); however, no reports concerning MRSA ceftaroline susceptibility have been reported in Switzerland. We tested the in vitro activity of ceftaroline against an archived set of 60 MRSA strains from the University Hospital of Geneva collected from 1994 to 2003. Our results surprisingly revealed ceftaroline-resistant strains (MIC, >1 μg/ml in 40/60 strains; EUCAST breakpoints, susceptible [S], ≤1 μg/ml; resistant [R], >1 μg/ml) were present from 1998 to 2003. The detected resistant strains predominantly belonged to sequence type 228 (ST228) (South German clonotype) but also to ST247 (Iberian clonotype). A sequence analysis of these strains revealed missense mutations in the penicillin-binding protein 2A (PBP2A) allosteric domain (N146K or E239K and N146K-E150K-G246E). The majority of our ST228 PBP2A mutations (N146K or E150K) were distinct from ST228 PBP2A allosteric domain mutations (primarily E239K) recently described for MRSA strains collected in Thailand and Spain during the 2010 Assessing Worldwide Antimicrobial Resistance Evaluation (AWARE) global surveillance program. We also found that similar allosteric domain PBP2A mutations (N146K) correlated with ceftaroline resistance in an independent external ST228 MRSA set obtained from the nearby University Hospital of Lausanne, Lausanne, Switzerland, collected from 2003 to 2008. Thus, ceftaroline resistance was observed in our archived strains (including two examples of an MIC of 4 µg/ml for the Iberian ST247 clonotype with the triple mutation N146K/E150K/G246E), at least as far back as 1998, considerably predating the commercial introduction of ceftaroline. Our results reinforce the notion that unknown parameters can potentially exert selective pressure on PBP2A that can subsequently modulate ceftaroline

  15. Missense mutations in PBP2A Affecting ceftaroline susceptibility detected in epidemic hospital-acquired methicillin-resistant Staphylococcus aureus clonotypes ST228 and ST247 in Western Switzerland archived since 1998.

    PubMed

    Kelley, William L; Jousselin, Ambre; Barras, Christine; Lelong, Emmanuelle; Renzoni, Adriana

    2015-04-01

    The development and maintenance of an arsenal of antibiotics is a major health care challenge. Ceftaroline is a new cephalosporin with activity against methicillin-resistant Staphylococcus aureus (MRSA); however, no reports concerning MRSA ceftaroline susceptibility have been reported in Switzerland. We tested the in vitro activity of ceftaroline against an archived set of 60 MRSA strains from the University Hospital of Geneva collected from 1994 to 2003. Our results surprisingly revealed ceftaroline-resistant strains (MIC, >1 μg/ml in 40/60 strains; EUCAST breakpoints, susceptible [S], ≤1 μg/ml; resistant [R], >1 μg/ml) were present from 1998 to 2003. The detected resistant strains predominantly belonged to sequence type 228 (ST228) (South German clonotype) but also to ST247 (Iberian clonotype). A sequence analysis of these strains revealed missense mutations in the penicillin-binding protein 2A (PBP2A) allosteric domain (N146K or E239K and N146K-E150K-G246E). The majority of our ST228 PBP2A mutations (N146K or E150K) were distinct from ST228 PBP2A allosteric domain mutations (primarily E239K) recently described for MRSA strains collected in Thailand and Spain during the 2010 Assessing Worldwide Antimicrobial Resistance Evaluation (AWARE) global surveillance program. We also found that similar allosteric domain PBP2A mutations (N146K) correlated with ceftaroline resistance in an independent external ST228 MRSA set obtained from the nearby University Hospital of Lausanne, Lausanne, Switzerland, collected from 2003 to 2008. Thus, ceftaroline resistance was observed in our archived strains (including two examples of an MIC of 4 µg/ml for the Iberian ST247 clonotype with the triple mutation N146K/E150K/G246E), at least as far back as 1998, considerably predating the commercial introduction of ceftaroline. Our results reinforce the notion that unknown parameters can potentially exert selective pressure on PBP2A that can subsequently modulate ceftaroline

  16. 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.

  17. 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

  18. 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.

  19. Methicillin-Resistant Staphylococcus aureus (MRSA) Infections in the Department of Defense (DOD): Annual Summary 2013

    DTIC Science & Technology

    2015-01-06

    Methicillin-Resistant Staphylococcus aureus (MRSA) Infections in the Department of Defense (DOD): Annual Summary 2013 NMCPHC-EDC-TR-44...December 2014 EpiData Center Department Abstract Methicillin-resistant Staphylococcus aureus (MRSA) infections are a national concern for public...Navy (DON) beneficiary populations. This report provides a summary of Methicillin-resistant Staphylococcus aureus (MRSA) incidence and prevalence

  20. 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.

  1. 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

  2. Antimicrobial resistance in methicillin susceptible and methicillin resistant Staphylococcus pseudintermedius of canine origin: literature review from 1980 to 2013.

    PubMed

    Moodley, Arshnee; Damborg, Peter; Nielsen, Søren Saxmose

    2014-07-16

    Staphylococcus pseudintermedius is a commensal and a common opportunistic pathogen causing mainly infections of the integumentary system in dogs. The recent emergence of multidrug-resistant S. pseudintermedius isolates, in particular methicillin-resistant strains (MRSP) is a threat to small animal health and highlights the need for antimicrobial resistance surveillance to detect trends and potentially perform timeous interventions. We systematically reviewed 202 published articles to investigate temporal changes in antimicrobial resistance in clinical and commensal S. pseudintermedius isolated from dogs in 27 countries between 1980 and 2013. Resistance to the most common antimicrobials tested for in published studies and important for the treatment of staphylococcal infections in dogs were assessed separately for methicillin resistant (MRSP) and methicillin susceptible (MSSP) isolates. Stratified by MSSP and MRSP, no significant increases in antimicrobial resistance were observed over time, except for the penicillinase-labile penicillins (penicillin and ampicillin) among MSSP. However, in recent years, a few studies have reported higher-level of resistance to amikacin, gentamicin and enrofloxacin amongst MSSP. The review highlights inconsistencies between studies as a result of several factors, for example the use of different antimicrobial susceptibility testing methods and interpretation criteria. We recommend that data on susceptibility in important companion animal pathogens are collected and presented in a more harmonized way to allow more precise comparison of susceptibility patterns between studies. One way to accomplish this would be through systematic surveillance either at the country-level or at a larger scale across countries e.g. EU level.

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

    PubMed Central

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

    2009-01-01

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

  4. 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.

  5. 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

  6. 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

  7. 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

  8. [Relatedness of methicillin-resistant coagulase-negative staphylococci].

    PubMed

    Bogiel, Tomasz; Mikucka, Agnieszka; Deptuła, Aleksander; Gospodarek, Eugenia

    2009-01-01

    Many identification and relatedness studies methods had been commonly used for epidemiological studies in microbiological laboratories. Apart from phenotypic methods, genotypic are also often used. The aim of this study was to compare, obtained by PFGE chromosomal DNA patterns of methicillin-resistant S. epidermidis strains isolated from clinical material. 46 methicillin-resistant S. epidermidis strains were included in this study. Most of them were isolated from wound swabs (65.2%) and catheters (19.6%) from different surgical clinics (76.1%). To identify strains and receive biochemical profiles, ID 32 Staph tests and GPI cards of Vitek 1 system were used. Pulsed-field gel electrophoresis and Tenover et al. interpretation were used to compare chromosomal DNA patterns of examined strains. 44 and 42 PFGE patterns of chromosomal DNA were received, using visual interpretation classifying two pairs of strains as the same, two pairs as closely related and three pairs as probably related. Strains classified as identical and similar in visual evaluation were indistinguishable in Molecular Analyst DST interpretation, probably due to tolerance in bands location pattern. Strains probably related in visual interpretation represent at least 96% similarity in Molecular Analyst DST but different susceptibility and biochemical profiles obtained by ID 32 Staph and Vitek 1. PFGE analysis had foremost capacity to distinguish methicillin-resistant S. epidermidis strains using visual interpretation and Molecular Analyst DST (Bio-Rad) program and seems to be useful method in epidemiological studies. Strains with the same PFGE pattern, had different susceptibility and biochemical profiles.

  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. Molecular nature of methicillin-resistant Staphylococcus aureus derived from explosive nosocomial outbreaks of the 1980s in Japan.

    PubMed

    Taneike, Ikue; Otsuka, Taketo; Dohmae, Soshi; Saito, Kohei; Ozaki, Kyoko; Takano, Misao; Higuchi, Wataru; Takano, Tomomi; Yamamoto, Tatsuo

    2006-04-17

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) with Panton-Valentine leukocidin (PVL) genes is increasing worldwide. Nosocomial outbreak-derived (hospital-acquired) MRSA (HA-MRSA) in Japan in the 1980s was also largely PVL(+). PVL(+) HA-MRSA and CA-MRSA shared the same multi-locus sequence type (ST30) and methicillin resistance cassette (SCCmecIV), but were divergent in oxacillin resistance, spa typing, PFGE analysis or clfA gene analysis. PVL(+) HA-MRSA, which probably originated in PVL(+)S. aureus ST30, was highly adhesive (carrying cna and bbp genes), highly-toxic (carrying luk(PV) and sea genes) and highly drug-resistant. PVL(+) HA-MRSA was once replaced by other PVL(-) HA-MRSA (e.g., ST5), and is re-emerging as CA-MRSA.

  11. Detection of methicillin/oxacillin resistance and typing in aminoglycoside-susceptible methicillin-resistant and kanamycin-tobramycin-resistant methicillin-susceptible Staphylococcus aureus.

    PubMed

    Hamdad, F; Donda, F; Lefebvre, J F; Laurans, G; Biendo, M; Thomas, D; Canarelli, B; Rousseau, F; Eb, F

    2006-01-01

    Eighty-five atypical isolates of Staphylococcus aureus divided into 73 aminoglycoside-susceptible methicillinresistant (AS-MRSA) and 12 kanamycin-tobramycin-resistant methicillin-susceptible (KTR-MSSA) were phenotypically and genotypically examined for methicillin resistance. Among these tests, the diffusion method using the oxacillin and cefoxitin disks on Mueller-Hinton agar with and without NaCl, the incubation at 35 degrees C or 30 degrees C for 24 or 48 hr, respectively, and the determination of oxacillin MICs by E-test were performed. We also examined the presence of the mecA gene by PCR and its product PBP 2a by the Slidex MRSA Detection test after induction by cefoxitin disk. All of the AS-MRSA strains (100%) were detected by the cefoxitin disk in all conditions and by the oxacillin disk on Mueller-Hinton agar with 2% of NaCl at 35 degrees C. Without NaCl, the sensitivity fell to 97.2% by oxacillin disk. The oxacillin MICs for these isolates ranged from 2 to 128 mg/L. The mecA gene determinant and its product PBP 2a were detected in all AS-MRSA strains. All KTR-MSSA strains were phenotypically methicillin-susceptible and oxacillin MICs were below or borderline of breakpoint (< or =2 mg/L). The mecA gene determinant and its product were detected in one strain. Pulsed-field gel electrophoresis (PFGE) was applied and revealed the presence of two major patterns A (36.9%) and B (46.2%) in AS-MRSA isolates and seven patterns in the KTR-MSSA strains.

  12. 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.

  13. 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.

  14. 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

  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. Dissemination of metal resistance genes among animal methicillin-resistant coagulase-negative Staphylococci.

    PubMed

    Argudín, M Angeles; Butaye, Patrick

    2016-04-01

    The use of metals as feed supplement has been recognized as a potential driver for co-selection of methicillin-resistant Staphylococcus aureus in pigs. However, the prevalence of these determinants in methicillin-resistant coagulase-negative staphylococci (MRCoNS) is largely unknown. In this study, a collection of 130 MRCoNS from pigs and veal calves were investigated for the presence of metal-resistance genes (czrC, copB, cadD, arsA) associated to SCCmec. Near half of the isolates carried metal resistance genes (czrC 5.4%, copB 38.5%, cadD 7.7%, arsA 26.2%) regardless of their SCCmec type. The increased use of metals in livestock animals, especially zinc in pigs in several European countries may co-select for methicillin-resistance in several staphylococcal species.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-10-01

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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

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

    PubMed

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

    2015-09-26

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

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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

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

    NASA Astrophysics Data System (ADS)

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

    1998-04-01

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

  1. 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

  2. The differential detection of methicillin-resistant, methicillin-susceptible and borderline oxacillin-resistant Staphylococcus aureus by surface plasmon resonance.

    PubMed

    Tawil, Nancy; Mouawad, Flaviana; Lévesque, Simon; Sacher, Edward; Mandeville, Rosemonde; Meunier, Michel

    2013-11-15

    Two hundred fifty Staphylococcus aureus clinical isolates were studied to determine their susceptibilities to β-lactam antibiotics. Among these isolates, 16 were methicillin-sensitive S. aureus (MSSA), 207 were methicillin-resistant S. aureus (MRSA) and 27 were borderline oxacillin-resistant S. aureus (BORSA). Currently, the reported mechanism of methicillin resistance in S. aureus is the production of a distinctive penicillin binding protein 2a (PBP2a), which exhibits low affinity toward β-lactams. A surface plasmon resonance biosensor was evaluated for its ability to identify MRSA and to distinguish these strains from MSSA and BORSA, by specifically detecting PBP2a. We found that the system permits label-free, real-time, specific detection of pathogens for concentrations as low as 10 colony forming units/milliliter (CFU/ml), in less than 20 min. This system promises to become a diagnostic tool for bacteria that cause major public concern in clinical settings.

  3. 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.

  4. Phenotypic and genotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA) from different sources in China.

    PubMed

    Chao, Guoxiang; Zhang, Xiaoping; Zhang, Xiaorong; Huang, Yao; Xu, Lan; Zhou, Liping; Yang, Weixia; Jiang, Yuan; Xue, Feng; Wu, Yantao

    2013-03-01

    A diverse collection of 261 Staphylococcus aureus strains from human, animal, food, and environmental sources were tested for the presence and type of SCCmec elements, antibiotic susceptibility to various antibiotics, and non-ß-lactam antibiotic resistance genes. About 18.39% (48/261) of strains were methicillin-resistant S. aureus (MRSA) including 29.75% (36/121) human strains of which 29 strains were hospital-acquired MRSA (HA-MRSA) and 7 strains were community-associated MRSA (CA-MRSA) and 19.67% (12/61) animal strains that all were CA-MRSA strains. The percentage of CA-MRSA strains from animals was significantly higher than that from human (p<0.01). Most of MRSA strains and a part of methicillin-susceptible S. aureus (MSSA) strains harbored unique combinations of non-ß-lactamase genes aac(6')/aph(2″), aph(3')-III, ant (4',4″), ermA, ermC, mrsA, tetM, and tetK. Antibiotic resistance genes were detected more frequently in HA-MRSA strains than in CA-MRSA strains (p<0.01). MRSA strains and MSSA strains had 22 and 39 antibiotic profiles to 15 tested antibiotics, respectively. The resistant proportion was higher in HA-MRSA strains than in CA-MSSA strains for various antibiotics, as well as higher in MRSA strains than in MSSA strains. Animal MRSA reservoirs (particularly pigs and cows) might represent an important source of human CA-MRSA. CA-MRSA strains might acquire more different resistance genes gradually, depending on the selective pressure of antibiotics in different regions or environments. CA-MRSA is not yet endemic in China, but could be prevalent in future, contributing to its acquiring more resistance genes and huge animal sources. Infection with multidrug-resistant MSSA strains acquired from food, animal, and human sources might also become a significant problem for human medicine, which warrants further study.

  5. 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

  6. Acquired Antibiotic Resistance Genes: An Overview

    PubMed Central

    van Hoek, Angela H. A. M.; Mevius, Dik; Guerra, Beatriz; Mullany, Peter; Roberts, Adam Paul; Aarts, Henk J. M.

    2011-01-01

    In this review an overview is given on antibiotic resistance (AR) mechanisms with special attentions to the AR genes described so far preceded by a short introduction on the discovery and mode of action of the different classes of antibiotics. As this review is only dealing with acquired resistance, attention is also paid to mobile genetic elements such as plasmids, transposons, and integrons, which are associated with AR genes, and involved in the dispersal of antimicrobial determinants between different bacteria. PMID:22046172

  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. Current concepts in antimicrobial therapy against select gram-positive organisms: methicillin-resistant Staphylococcus aureus, penicillin-resistant pneumococci, and vancomycin-resistant enterococci.

    PubMed

    Rivera, Ana Maria; Boucher, Helen W

    2011-12-01

    Gram-positive bacteria cause a broad spectrum of disease in immunocompetent and immunocompromised hosts. Despite increasing knowledge about resistance transmission patterns and new antibiotics, these organisms continue to cause significant morbidity and mortality, especially in the health care setting. Methicillin-resistant Staphylococcus aureus poses major problems worldwide as a cause of nosocomial infection and has emerged as a cause of community-acquired infections. This change in epidemiology affects choices of empirical antibiotics for skin and skin-structure infections and community-acquired pneumonia in many settings. Throughout the world, the treatment of community-acquired pneumonia and other respiratory tract infections caused by penicillin-resistant Streptococcus pneumoniae has been complicated by resistance to β-lactam and macrolide antibacterial drugs. Vancomycin-resistant enterococci are a major cause of infection in the hospital setting and remain resistant to treatment with most standard antibiotics. Treatment of diseases caused by resistant gram-positive bacteria requires appropriate use of available antibiotics and stewardship to prolong their effectiveness. In addition, appropriate and aggressive infection control efforts are vital to help prevent the spread of resistant pathogens.

  9. 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

  10. 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

  11. [Methicillin resistance detection in Staphylococcus aureus: comparison between conventional methods and MRSA-Screen latex agglutination technique].

    PubMed

    Soloaga, R; Corso, A; Gagetti, P; Faccone, D; Galas, M

    2004-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen that has emerged over the last four decades, causing both nosocomial and community-acquired infections. Rapid and accurate detection of methicillin resistance in S. aureus is important for the use of appropriate antimicrobial therapy and for the control of nosocomial spread of MRSA strains. We evaluated the efficiency of conventional methods for detection of methicillin resistance such as the disk diffusion, agar dilution, oxacillin agar screen test, and the latex agglutination test MRSA-Screen latex, in 100 isolates of S. aureus, 79 mecA positive and 21 mecA negative. The MRSA-Screen latex (Denka Seiken, Niigata, Japón), is a latex agglutination method that detects the presence of PLP-2a, product of mecA gene in S. aureus. The PCR of the mecA gene was used as the "gold standard" for the evaluation of the different methods tested. The percentages of sensitivity and specificity were as follows: disk difusión 97 and 100%, agar dilution 97 and 95%, oxacillin agar screen test 100 and 100%, and MRSA-Screen latex, 100 and 100 %. All methods presented high sensitivity and specificity, but MRSA-Screen latex had the advantage of giving a reliable result, equivalent to PCR, in only 15 minutes.

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

    PubMed

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

    2015-11-01

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

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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.

  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. 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

  20. Natural and acquired macrolide resistance in mycobacteria.

    PubMed

    Doucet-Populaire, F; Buriánková, K; Weiser, J; Pernodet, J-L

    2002-12-01

    The genus Mycobacterium contains two of the most important human pathogens, Mycobacterium tuberculosis and Mycobacterium leprae, the etiologic agents of tuberculosis and leprosy, respectively. Other mycobacteria are mostly saprophytic organisms, living in soil and water, but some of them can cause opportunistic infections. The increasing incidence of tuberculosis as well as infections with non-tuberculous mycobacteria (NTM) in AIDS patients has renewed interest in molecular mechanisms of drug resistance in these pathogens. Mycobacteria show a high degree of intrinsic resistance to most common antibiotics. For instance, species from the M. tuberculosis complex (MTC) are intrinsically resistant to macrolides. Nevertheless, some semi-synthetic macrolides as the erythromycin derivatives clarithromycin, azithromycin and most recently the ketolides, are active against NTM, particularly Mycobacterium avium, and some of them are widely used for infection treatment. However, shortly after the introduction of these new drugs, resistant strains appeared due to mutations in the macrolide target, the ribosome. The mycobacterial cell wall with its specific composition and structure is considered to be a major factor in promoting the natural resistance of mycobacteria to various antibiotics. However, to explain the difference in macrolide sensitivity between the MTC and NTM, the synergistic contribution of a specific resistance mechanism might be required, in addition to possible differences in cell wall permeability. This mini-review summarizes the current knowledge on the natural and acquired macrolide resistance in mycobacteria, gives an overview of potential mechanisms implicated in the intrinsic resistance and brings recent data concerning a macrolide resistance determinant in the MTC.

  1. 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.

  2. 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.

  3. 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.

  4. 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

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

    PubMed Central

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

    2005-01-01

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

  6. 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.

  7. Genetic and phenotypic characterization of methicillin-resistant staphylococci isolated from veterinary hospitals in South Korea.

    PubMed

    Moon, Bo Youn; Youn, Jung-Ho; Shin, Sook; Hwang, Sun Young; Park, Yong Ho

    2012-05-01

    Staphylococci were isolated from veterinary staff, hospitalized animals, and medical equipment from 2 major tertiary veterinary hospitals in South Korea to investigate antimicrobial resistance and genetic relatedness. The detection rate for staphylococci was 55.2% (111/201 samples), and 11 species were identified among the collected staphylococcal strains. The most prevalent species were Staphylococcus pseudintermedius (52/111, 46.8%), Staphylococcus epidermidis (21/111, 18.9%), and Staphylococcus aureus (19/111, 17.1%). The methicillin-resistance rates of staphylococci isolated from veterinary staff and medical equipment were higher than those from hospitalized animals. The genotype of methicillin-resistant S. aureus (MRSA) strains in the current study was sequence type (ST)72-SCCmec IVc-t324, which is similar to the genotype of prevalent MRSA strains in human beings and food animals in South Korea. Among the mecA-positive S. pseudintermedius isolates, SCCmec V was most prevalent in strains originating from both veterinary staff and hospitalized animals. SCCmec IVa was detected in methicillin-resistant S. epidermidis, whereas SCCmec IVc was found in other methicillin-resistant, coagulase-negative staphylococci. The SCCmec typing, antimicrobial susceptibility tests, and pulsed field gel electrophoresis results showed that methicillin-resistant staphylococci dissemination between hospitalized animals and veterinary staff is possible in South Korean veterinary hospitals.

  8. Histones from Avian Erythrocytes Exhibit Antibiofilm activity against methicillin-sensitive and methicillin-resistant Staphylococcus aureus

    PubMed Central

    Rose-Martel, Megan; Kulshreshtha, Garima; Ahferom Berhane, Nahom; Jodoin, Joelle; Hincke, Maxwell T.

    2017-01-01

    Staphylococcus aureus, a human pathogen associated with many illnesses and post-surgical infections, can resist treatment due to the emergence of antibiotic-resistant strains and through biofilm formation. The current treatments for chronic biofilm infections are antibiotics and/or surgical removal of the contaminated medical device. Due to higher morbidity and mortality rates associated with overuse/misuse of antibiotics, alternate treatments are essential. This study reports the antibiofilm activity of avian erythrocyte histones against methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). Fluorescence and scanning electron microscopy revealed membrane damage to bacteria in histone-treated biofilms. Histones and indolicidin (positive control) increased the expression of apsS and apsR, which are associated with the Antimicrobial Peptide (AMP) sensor/regulator system in S. aureus. The expression of dltB, and vraF, associated with AMP resistance mechanisms, were under histone inducible control in the biofilm-embedded bacterial cells. The time kill kinetics for histones against S. aureus revealed a rapid biocidal activity (<5 min). Purified erythrocyte-specific histone H5 possessed 3–4 fold enhanced antimicrobial activity against planktonic cells compared to the histone mixture (H1, H2A, H2B, H3, H4, H5). These results demonstrate the promise of histones and histone-like derivatives as novel antibiotics against pathogens in their planktonic and biofilm forms. PMID:28378802

  9. 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

  10. 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.

  11. 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

  12. 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).

  13. 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

  14. 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.

  15. The role of primary care prescribers in the diagnosis and management of community-associated methicillin-resistant Staphylococcus aureus skin and soft tissue infections.

    PubMed

    Lawrence, Kenneth R; Golik, Monica V; Davidson, Lisa

    2009-01-01

    Nosocomial infections caused by methicillin-resistant Staphylococcus aureus were first reported in the United States in the early 1960s. Beginning in the 1990s, healthy individuals from the community with no risk factors for resistant bacteria began presenting with methicillin-resistant Staphylococcus aureus infections, acquiring the name "community-associated methicillin-resistant Staphylococcus aureus" (CA-MRSA). CA-MRSA has a tendency to affect the skin and skin structures, generally in the form of abscesses and furuncles, carbuncles, and cellulitis. Cases of invasive infections including bacteremia, endocarditis, and necrotizing pneumonia have also been reported. A patient complaint of a "spider bite" is frequently associated with CA-MRSA. CA-MRSA and the traditional health care-associated methicillin-resistant Staphylococcus aureus are distinguished by their genetic composition, virulence factors, and susceptibility patterns to non-beta-lactam antibiotics. Appropriate management of CA-MRSA skin and skin structure infections includes incision and drainage of infected tissue and appropriate antimicrobial therapy. It has been suggested that when prevalence of CA-MRSA within a community eclipses 10%-15%, empiric use of non-beta-lactam antibiotics with in vitro activity against CA-MRSA be initiated when treating skin and skin structure infections. CA-MRSA retains susceptibility to a range of older antibiotics available in oral formulations such as minocycline, doxycycline, sulfamethoxazole-trimethoprim, moxifloxacin, levofloxacin, and clindamycin. Local susceptibility patterns and individual patient factors should guide the selection of antibiotics.

  16. [Co-trimoxazole resistance in methicillin-resistant staphylococci isolated from clinical material in 2001-2003].

    PubMed

    Mikołajczyk, Dorota; Kaczmarek, Agnieszka; Budzytiska, Anna; Gospodarek, Eugenia

    2005-01-01

    The aim of this study was to determine resistance to co-trimoxazole among 476 strains of methicillin-resistant Staphylococus aureus (MRSA) and 2137 strains of methicillin resistant coagulase-negative staphylococci (MRCNS) isolation during three years (2001-2003). Their susceptibility testing were performed by the disc-diffusion techniques according to recomendation of NCCLS (National Committe for Clinical Laboratory Standards). Co-trimoxazole resistance was demonstrated more frequently among MRCNS (52,8%, 51,4%, 63,9% in 2001, 2002, 2003), than among MRSA (23,4%, 19,5%, 16,8% adequately).

  17. 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

  18. 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.

  19. 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

  20. 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

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

    PubMed

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

    2014-07-01

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

  2. Signal regulators of systemic acquired resistance

    PubMed Central

    Gao, Qing-Ming; Zhu, Shifeng; Kachroo, Pradeep; Kachroo, Aardra

    2015-01-01

    Salicylic acid (SA) is an important phytohormone that plays a vital role in a number of physiological responses, including plant defense. The last two decades have witnessed a number of breakthroughs related to biosynthesis, transport, perception and signaling mediated by SA. These findings demonstrate that SA plays a crictical role in both local and systemic defense responses. Systemic acquired resistance (SAR) is one such SA-dependent response. SAR is a long distance signaling mechanism that provides broad spectrum and long-lasting resistance to secondary infections throughout the plant. This unique feature makes SAR a highly desirable trait in crop production. This review summarizes the recent advances in the role of SA in SAR and discusses its relationship to other SAR inducers. PMID:25918514

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

    PubMed

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

    2015-04-01

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

  4. Incidence and treatment of methicillin-resistant S. aureus infection in cystic fibrosis patients: a cohort study.

    PubMed

    Bittencourt, Paloma Horejs; Pimentel, Carlos Sidney Silva; Bonfim, Bianca Sampaio; Marostica, Paulo José; Souza, Edna Lúcia

    In Brazil the knowledge about methicillin-resistant Staphylococcus aureus infection in cystic fibrosis patients is scarce. This study aimed to determine the incidence of respiratory tract colonization and the identification rates after a standardized treatment. A retrospective cohort was performed highlighting the history of respiratory colonizations between January 2008 and June 2015. Patients under the age of 21 years with cystic fibrosis confirmed by sweat test or genetic study receiving care at the outpatient clinics of a Teaching Hospital were included. The treatment consisted of trimethoprim/sulfamethoxazole, rifampicin, nasal mupirocin and chlorhexidine 2%. The mean follow-up period was of 22.2 months and those with ≥3 negative cultures were considered free of methicillin-resistant Staphylococcus aureus. Forty-two patients were included. Methicillin-resistant Staphylococcus aureus was identified in six patients. Most patients had methicillin-sensitive S. aureus isolation prior to methicillin-resistant Staphylococcus aureus. Five children used the standardized treatment, none presented side effects. Only one child had a new isolation of methicillin-resistant Staphylococcus aureus during follow-up (after 20 months). The incidence of methicillin-resistant Staphylococcus aureus infection was high and occurred in young patients. The therapeutic regimen was effective, safe and being a good option to treat methicillin-resistant Staphylococcus aureus infection.

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

    PubMed

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

    2014-11-01

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

  6. Mechanisms of polymyxin resistance: acquired and intrinsic resistance in bacteria

    PubMed Central

    Olaitan, Abiola O.; Morand, Serge; Rolain, Jean-Marc

    2014-01-01

    Polymyxins are polycationic antimicrobial peptides that are currently the last-resort antibiotics for the treatment of multidrug-resistant, Gram-negative bacterial infections. The reintroduction of polymyxins for antimicrobial therapy has been followed by an increase in reports of resistance among Gram-negative bacteria. Some bacteria, such as Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii, develop resistance to polymyxins in a process referred to as acquired resistance, whereas other bacteria, such as Proteus spp., Serratia spp., and Burkholderia spp., are naturally resistant to these drugs. Reports of polymyxin resistance in clinical isolates have recently increased, including acquired and intrinsically resistant pathogens. This increase is considered a serious issue, prompting concern due to the low number of currently available effective antibiotics. This review summarizes current knowledge concerning the different strategies bacteria employ to resist the activities of polymyxins. Gram-negative bacteria employ several strategies to protect themselves from polymyxin antibiotics (polymyxin B and colistin), including a variety of lipopolysaccharide (LPS) modifications, such as modifications of lipid A with phosphoethanolamine and 4-amino-4-deoxy-L-arabinose, in addition to the use of efflux pumps, the formation of capsules and overexpression of the outer membrane protein OprH, which are all effectively regulated at the molecular level. The increased understanding of these mechanisms is extremely vital and timely to facilitate studies of antimicrobial peptides and find new potential drugs targeting clinically relevant Gram-negative bacteria. PMID:25505462

  7. Lack of Involvement of Fenton Chemistry in Death of Methicillin-Resistant and Methicillin-Sensitive Strains of Staphylococcus aureus and Destruction of Their Genomes on Wet or Dry Copper Alloy Surfaces

    PubMed Central

    2016-01-01

    The pandemic of hospital-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has declined, but the evolution of strains with enhanced virulence and toxins and the increase of community-associated infections are still a threat. In previous studies, 107 MRSA bacteria applied as simulated droplet contamination were killed on copper and brass surfaces within 90 min. However, contamination of surfaces is often via finger tips and dries rapidly, and it may be overlooked by cleaning regimes (unlike visible droplets). In this new study, a 5-log reduction of a hardy epidemic strain of MRSA (epidemic methicillin-resistant S. aureus 16 [EMRSA-16]) was observed following 10 min of contact with copper, and a 4-log reduction was observed on copper nickel and cartridge brass alloys in 15 min. A methicillin-sensitive S. aureus (MSSA) strain from an osteomyelitis patient was killed on copper surfaces in 15 min, and 4-log and 3-log reductions occurred within 20 min of contact with copper nickel and cartridge brass, respectively. Bacterial respiration was compromised on copper surfaces, and superoxide was generated as part of the killing mechanism. In addition, destruction of genomic DNA occurs on copper and brass surfaces, allaying concerns about horizontal gene transfer and copper resistance. Incorporation of copper alloy biocidal surfaces may help to reduce the spread of this dangerous pathogen. PMID:26826226

  8. Lack of Involvement of Fenton Chemistry in Death of Methicillin-Resistant and Methicillin-Sensitive Strains of Staphylococcus aureus and Destruction of Their Genomes on Wet or Dry Copper Alloy Surfaces.

    PubMed

    Warnes, Sarah L; Keevil, C William

    2016-01-29

    The pandemic of hospital-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has declined, but the evolution of strains with enhanced virulence and toxins and the increase of community-associated infections are still a threat. In previous studies, 10(7) MRSA bacteria applied as simulated droplet contamination were killed on copper and brass surfaces within 90 min. However, contamination of surfaces is often via finger tips and dries rapidly, and it may be overlooked by cleaning regimes (unlike visible droplets). In this new study, a 5-log reduction of a hardy epidemic strain of MRSA (epidemic methicillin-resistant S. aureus 16 [EMRSA-16]) was observed following 10 min of contact with copper, and a 4-log reduction was observed on copper nickel and cartridge brass alloys in 15 min. A methicillin-sensitive S. aureus (MSSA) strain from an osteomyelitis patient was killed on copper surfaces in 15 min, and 4-log and 3-log reductions occurred within 20 min of contact with copper nickel and cartridge brass, respectively. Bacterial respiration was compromised on copper surfaces, and superoxide was generated as part of the killing mechanism. In addition, destruction of genomic DNA occurs on copper and brass surfaces, allaying concerns about horizontal gene transfer and copper resistance. Incorporation of copper alloy biocidal surfaces may help to reduce the spread of this dangerous pathogen.

  9. 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

  10. 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.

  11. 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.

  12. Identification of Functional Regulatory Residues of the β -Lactam Inducible Penicillin Binding Protein in Methicillin-Resistant Staphylococcus aureus.

    PubMed

    Mbah, Andreas N; Isokpehi, Raphael D

    2013-01-01

    Resistance to methicillin by Staphylococcus aureus is a persistent clinical problem worldwide. A mechanism for resistance has been proposed in which methicillin resistant Staphylococcus aureus (MRSA) isolates acquired a new protein called β -lactam inducible penicillin binding protein (PBP-2'). The PBP-2' functions by substituting other penicillin binding proteins which have been inhibited by β -lactam antibiotics. Presently, there is no structural and regulatory information on PBP-2' protein. We conducted a complete structural and functional regulatory analysis of PBP-2' protein. Our analysis revealed that the PBP-2' is very stable with more hydrophilic amino acids expressing antigenic sites. PBP-2' has three striking regulatory points constituted by first penicillin binding site at Ser25, second penicillin binding site at Ser405, and finally a single metallic ligand binding site at Glu657 which binds to Zn(2+) ions. This report highlights structural features of PBP-2' that can serve as targets for developing new chemotherapeutic agents and conducting site direct mutagenesis experiments.

  13. Bovine mastitis outbreak in Japan caused by methicillin-resistant Staphylococcus aureus New York/Japan clone.

    PubMed

    Hata, Eiji

    2016-05-01

    Many methicillin-resistant Staphylococcus aureus (MRSA) strains are multidrug-resistant; consequently, infectious diseases involving MRSA are recognized as troublesome diseases not only in human health care but also in animal health care. A bovine mastitis case caused by MRSA isolates of the New York/Japan clone (NJC), which occurred in Japan in 2005, was monitored in the current study. Isolates of the NJC are typical of hospital-acquired MRSA in Japan. The genetic backgrounds of these strains differ from those of bovine-associated S. aureus, which are typically of clonal complex (CC)97, CC705, and CC133. Moreover, the NJC isolates in this bovine outbreak possessed a β-hemolysin-converting bacteriophage and an immune evasion cluster, as found in the NJC isolates from humans, so it is possible that this clone was introduced into the dairy herd by a human carrier. Most bovine intramammary infections (IMIs) caused by the NJC isolates in our study were asymptomatic, and obvious clinical signs were recognized in only the first 3 infected cows. Of a total of 78 cows, 31 cows were MRSA carriers, and these carrier cows were detected by testing the milk of all lactating cows at 1-month intervals. These S. aureus carrier cows were culled or the infected quarter was dried off and no longer milked. Both IMI and mastitis caused by MRSA were completely eradicated after 5 months. Genotyping data suggested that exchanging of the staphylococcal cassette chromosome mec (the determining factor in methicillin resistance) occurred easily between MRSA and methicillin-sensitive S. aureus in the udders of carrier cows. This case study demonstrates an effective procedure against the spread of MRSA in a dairy herd, and highlights the risk of emergence of new MRSA strains in a dairy herd.

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

    PubMed

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

    2014-01-01

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

  15. Molecular surveillance and population structure analysis of methicillin-susceptible and methicillin-resistant Staphylococcus aureus in high-risk wards.

    PubMed

    Sergi, Simona; Donnarumma, Francesca; Mastromei, Giorgio; Goti, Emanuele; Nicoletti, Pierluigi; Pecile, Patrizia; Cecconi, Daniela; Mannino, Roberta; Fanci, Rosa; Bosi, Alberto; Bartolozzi, Benedetta; Casalone, Enrico

    2009-10-01

    In this study we report the results of analysis of 253 isolates of Staphylococcus aureus (132 methicillin [meticillin]-resistant S. aureus [MRSA] isolates and 121 methicillin-susceptible S. aureus [MSSA] isolates) from 209 patients admitted to 18 high-risk wards of six hospitals located in Florence, Italy, over an 8-month period during which a program of epidemiological surveillance of hospital-acquired infections was conducted. The majority (69%) of the 87 reported S. aureus infections were caused by MRSA. No outbreak events have been reported. All the isolates were typed by amplified fragment length polymorphism (AFLP), and AFLP profiles were analyzed in order to define similarity groups. The discriminatory power of AFLP is very high with MSSA (Simpson index of diversity [D], 95.9%), whereas its resolution capability with MRSA (D, 44.7%) is hampered by the well-known high clonality of these populations (the main MRSA group accounted for 74% of the MRSA isolates). Combining AFLP, improved by visual inspection of polymorphisms, with multiplex PCR greatly increases MRSA resolution (D, 85.5%), resolving the MRSA population to a level that is one of the highest reported in the literature. Widespread and sporadic clones of MSSA and MRSA were identified, and their diffusion in the different hospitals and wards over the surveillance period was studied. The understanding of MSSA and MRSA population structures should be the starting point for the design of a more rational surveillance program for S. aureus species, maximizing benefits and reducing the cost of infection control strategies.

  16. Typing of Panton-Valentine leukocidin-encoding phages carried by methicillin-susceptible and methicillin-resistant Staphylococcus aureus from Italy.

    PubMed

    Sanchini, A; Del Grosso, M; Villa, L; Ammendolia, M G; Superti, F; Monaco, M; Pantosti, A

    2014-11-01

    Panton-Valentine leukocidin (PVL) is the hallmark of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) but can also be found in methicillin-susceptible S. aureus (MSSA) sharing pathogenic and epidemiological characteristics of CA-MRSA. PVL is encoded by two co-transcribed genes that are carried by different staphylococcal bacteriophages. We applied an extended PCR-based typing scheme for the identification of two morphological groups (elongated-head group and icosahedral-head group I phages) and specific PVL phage types in S. aureus isolates recovered in Italy. We examined 48 PVL-positive isolates (25 MSSA and 23 MRSA) collected from different hospital laboratories from April 2005 to May 2011. spa typing, multilocus sequence typing and staphylococcal cassette chromosome mec typing were applied to categorize the isolates. Phage typeability was 48.0% in MSSA and 91.3% in MRSA, highlighting the limitation of the PCR typing scheme when applied to PVL-positive MSSA. Five different PVL phages and two variants of a known phage were detected, the most prevalent being ΦSa2usa, recovered in 15 out of 48 (31.2%) isolates, and carried by both MSSA and MRSA belonging to CC8 and CC5. The recently described ΦTCH60 was recovered in four isolates. A PVL phage (ΦSa119) from an ST772 MRSA, that was not detected using the previous typing scheme, was sequenced, and new primers were designed for the identification of the icosahedral-head group II PVL phages present in ST772 and ST59 MRSA. A comprehensive PVL-phage typing can contribute to the understanding of the epidemiology and evolution of PVL-positive MSSA and MRSA.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  20. 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.

  1. 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.

  2. 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…

  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. 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

  5. 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

  6. Draft Genome Sequence of a Canine Isolate of Methicillin-Resistant Staphylococcus haemolyticus

    PubMed Central

    Wigmore, Sarah M.; Wareham, David W.

    2017-01-01

    ABSTRACT Staphylococcus haemolyticus strain SW007 was isolated from a nasal swab taken from a healthy dog. The isolate is resistant to methicillin, mupirocin, macrolides, and sulfonamides. The SW007 draft genome is 2,325,410 bp and contains 2,277 coding sequences, including 60 tRNAs and nine complete rRNA-coding regions. PMID:28385855

  7. 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

  8. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Free radicals mediate systemic acquired resistance.

    PubMed

    Wang, Caixia; El-Shetehy, Mohamed; Shine, M B; Yu, Keshun; Navarre, Duroy; Wendehenne, David; Kachroo, Aardra; Kachroo, Pradeep

    2014-04-24

    Systemic acquired resistance (SAR) is a form of resistance that protects plants against a broad spectrum of secondary infections. However, exploiting SAR for the protection of agriculturally important plants warrants a thorough investigation of the mutual interrelationships among the various signals that mediate SAR. Here, we show that nitric oxide (NO) and reactive oxygen species (ROS) serve as inducers of SAR in a concentration-dependent manner. Thus, genetic mutations that either inhibit NO/ROS production or increase NO accumulation (e.g., a mutation in S-nitrosoglutathione reductase [GSNOR]) abrogate SAR. Different ROS function additively to generate the fatty-acid-derived azelaic acid (AzA), which in turn induces production of the SAR inducer glycerol-3-phosphate (G3P). Notably, this NO/ROS→AzA→G3P-induced signaling functions in parallel with salicylic acid-derived signaling. We propose that the parallel operation of NO/ROS and SA pathways facilitates coordinated regulation in order to ensure optimal induction of SAR.

  16. In vitro activities of rifapentine and rifampin, alone and in combination with six other antibiotics, against methicillin-susceptible and methicillin-resistant staphylococci of different species.

    PubMed Central

    Varaldo, P E; Debbia, E; Schito, G C

    1985-01-01

    The antistaphylococcal activity of rifapentine, a new rifamycin SV derivative, was evaluated in vitro and compared with that of rifampin. A total of 313 staphylococcal strains freshly isolated from clinical material and including representatives of all currently recognized Staphylococcus species of human origin were used. The susceptibility to methicillin of all the test strains was determined preliminarily. Despite minor differences with some species, the MICs of rifapentine were found to be substantially similar to those of rifampin. Methicillin-resistant strains of all species were most resistant to rifapentine and rifampin than were their methicillin-susceptible counterparts. For most strains tested, the MBCs of both rifamycins exceeded by twofold the respective MICs. Both the checkerboard dilution and time-kill methods were used to determine the interactions of rifapentine or rifampin with six different antibiotics: cefamandole, vancomycin, teicoplanin, gentamicin, erythromycin, and fusidic acid. No significant differences between the two rifamycins in the combinations were observed against either methicillin-susceptible or methicillin-resistant strains. Minor differences were noted depending on the second antibiotic tested or the staphylococcal species examined. Antagonism was never observed, and indifference was the prevalent response. Cases of synergism were observed occasionally with the checkerboard method and slightly more often with the time-kill method. PMID:3847272

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

    PubMed

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

    2015-12-01

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

  18. 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

  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. 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

  1. 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.

  2. Prevalence of Chlorhexidine-Resistant Methicillin-Resistant Staphylococcus aureus following Prolonged Exposure

    PubMed Central

    Millar, Eugene V.; Crawford, Katrina B.; Cui, Tianyuan; Lanier, Jeffrey B.; Tribble, David R.; Ellis, Michael W.

    2014-01-01

    Chlorhexidine has been increasingly utilized in outpatient settings to control methicillin-resistant Staphylococcus aureus (MRSA) outbreaks and as a component of programs for MRSA decolonization and prevention of skin and soft-tissue infections (SSTIs). The objective of this study was to determine the prevalence of chlorhexidine resistance in clinical and colonizing MRSA isolates obtained in the context of a community-based cluster-randomized controlled trial for SSTI prevention, during which 10,030 soldiers were issued chlorhexidine for body washing. We obtained epidemiological data on study participants and performed molecular analysis of MRSA isolates, including PCR assays for determinants of chlorhexidine resistance and high-level mupirocin resistance and pulsed-field gel electrophoresis (PFGE). During the study period, May 2010 to January 2012, we identified 720 MRSA isolates, of which 615 (85.4%) were available for molecular analysis, i.e., 341 clinical and 274 colonizing isolates. Overall, only 10 (1.6%) of 615 isolates were chlorhexidine resistant, including three from the chlorhexidine group and seven from nonchlorhexidine groups (P > 0.99). Five (1.5%) of the 341 clinical isolates and five (1.8%) of the 274 colonizing isolates harbored chlorhexidine resistance genes, and four (40%) of the 10 possessed genetic determinants for mupirocin resistance. All chlorhexidine-resistant isolates were USA300. The overall prevalence of chlorhexidine resistance in MRSA isolates obtained from our study participants was low. We found no association between extended chlorhexidine use and the prevalence of chlorhexidine-resistant MRSA isolates; however, continued surveillance is warranted, as this agent continues to be utilized for infection control and prevention efforts. PMID:24841265

  3. In vitro selection and characterization of ceftobiprole-resistant methicillin-resistant Staphylococcus aureus.

    PubMed

    Banerjee, Ritu; Gretes, Michael; Basuino, Li; Strynadka, Natalie; Chambers, Henry F

    2008-06-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to beta-lactam antibiotics because it expresses penicillin-binding protein 2a (PBP2a), a low-affinity penicillin-binding protein. An investigational broad-spectrum cephalosporin, ceftobiprole (BPR), binds PBP2a with high affinity and is active against MRSA. We hypothesized that BPR resistance could be mediated by mutations in mecA, the gene encoding PBP2a. We selected BPR-resistant mutants by passage in high-volume broth cultures containing subinhibitory concentrations of BPR. We used strain COLnex (which lacks chromosomal mecA) transformed with pAW8 (a plasmid vector only), pYK20 (a plasmid carrying wild-type mecA), or pYK21 (a plasmid carrying a mutant mecA gene corresponding to five PBP2a mutations). All strains became resistant to BPR by day 9 of passaging, but MICs continued to increase until day 21. MICs increased 256-fold (from 1 to 256 microg/ml) for pAW8, 32-fold (from 4 to 128 microg/ml) for pYK20, and 8-fold (from 16 to 128 mug/ml) for pYK21. Strains carrying wild-type or mutant mecA developed six (pYK20 transformants) or four (pYK21 transformants) new mutations in mecA. The transformation of COLnex with a mecA mutant plasmid conferred BPR resistance, and the loss of mecA converted resistant strains into susceptible ones. Modeling studies predicted that several of the mecA mutations altered BPR binding; other mutations may have mediated resistance by influencing interactions with other proteins. Multiple mecA mutations were associated with BPR resistance in MRSA. BPR resistance also developed in the strain lacking mecA, suggesting a role for chromosomal genes.

  4. The multifaceted resources and microevolution of the successful human and animal pathogen methicillin-resistant Staphylococcus aureus

    PubMed Central

    Figueiredo, Agnes Marie Sá; Ferreira, Fabienne Antunes

    2014-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important bacterial pathogens based on its incidence and the severity of its associated infections. In addition, severe MRSA infections can occur in hospitalised patients or healthy individuals from the community. Studies have shown the infiltration of MRSA isolates of community origin into hospitals and variants of hospital-associated MRSA have caused infections in the community. These rapid epidemiological changes represent a challenge for the molecular characterisation of such bacteria as a hospital or community-acquired pathogen. To efficiently control the spread of MRSA, it is important to promptly detect the mecA gene, which is the determinant of methicillin resistance, using a polymerase chain reaction-based test or other rapidly and accurate methods that detect the mecA product penicillin-binding protein (PBP)2a or PBP2’. The recent emergence of MRSA isolates that harbour a mecA allotype, i.e., the mecC gene, infecting animals and humans has raised an additional and significant issue regarding MRSA laboratory detection. Antimicrobial drugs for MRSA therapy are becoming depleted and vancomycin is still the main choice in many cases. In this review, we present an overview of MRSA infections in community and healthcare settings with focus on recent changes in the global epidemiology, with special reference to the MRSA picture in Brazil. PMID:24789555

  5. Community acquired multi drug resistant Staphylococcus aureus in a rural setting of North Western Ethiopia: a tough challenge.

    PubMed

    Tibebu, Martha; Embiyale, Wondimagegn

    2014-07-01

    Commnunity acquired Methicillin Resistant Staphylococcus aureus species are common causes of skin and soft tissue infections. Foot ulcer of former leprosy patients can be invaded by a multi-microbial infection. Cervicitis is usually caused by certain sexually transmitted agents. Here we report a series of cases of methicillin-resistant Staphylococcus aureus, isolated from two patients presenting with foot ulcer and cervicitis respectively, both in an outpatient or community setting (community onset) in rural North Western Ethiopia. The strains were resistant to all commonly available drugs such as trimethoprim-sulfamethoxazole, ciprofloxacin, erythromycin, chloramphenicol and tetracycline but sensitive to clindamycin. This is the first report of CA-MRSA in the study area.

  6. 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

  7. Prospective Analysis Methicillin-resistant Staphylococcus aureus and its Risk Factors

    PubMed Central

    Abdallah, Soad A; Al-Asfoor, Khulood K; Salama, Mona F; Al-Awadi, Bashayer M

    2013-01-01

    Background: Since the early nineties, a new methicillin-resistant Staphylococcus aureus (MRSA) has existed in a form correlating with community health personnel. Community-acquired MRSA (CA-MRSA) could be differentiated from healthcare-associated MRSA (HA-MRSA) microbiologically, epidemiologically, and molecularly. Aims: To determine the prevalence, risk factors of MRSA infections in community and hospital. Settings: The incidence and risk factors for CA-MRSA and HA-MRSA among patients of medical, surgical, and pediatrics wards and ICU at a Kuwaiti teaching hospital between 1 March 2011 and 30 November 2011 were studied. Materials and Methods: Cultures for MRSA were taken from nasal (nostril), groin, axilla, wound, sputum, or throat, and the inguinal area in all enrolled patients upon admission. All preserved isolates were examined for their susceptibility to different types of antibiotics. Results and Conclusion: A total of 71 MRSA patients admitted to different hospital wards were examined. Among these patients, 52 (73.2%) were carriers of MRSA before they were admitted to the hospital. Nineteen patients (26.8%) were found to have acquired MRSA during their stay in the hospital. Twenty-nine patients (40.8%) were given mupirocin local skin antibiotic. Binomial and the t-test (paired) were used to compare the prevalence of CA-MRSA and HA-MRSA; significant correlation (P < 0.05) between the type of MRSA and different wards, sites, and lengths of hospital stay was found. The level of serum albumin that is routinely measured at hospital admission is a predictor to MRSA infection. This study suggests that S. aureus and MRSA should become a national priority for disease control to avoid outbreaks. PMID:23599613

  8. Nasal carriage of methicillin resistant Staphylococcus aureus and their antibiotic susceptibility patterns in children attending day-care centers.

    PubMed

    Sedighi, Iraj; Moez, Hoda Jaefari; Alikhani, Mohammad Yousef

    2011-09-01

    Nasal colonization with community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) is being increasingly reported, especially in places where people are in close contact and in reduced hygiene, such as day-care centers. In this study we investigated the frequency of MRSA colonization and their antibiotic susceptibility patterns in 1-6 years old children of day-care centers in Hamadan, West of Iran.Five hundred nasal swabs were collected from children of 27 day-care centers that had no risk factors for colonization by S. aureus. The specimens were cultured for isolation of S. aureus by standard methods. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. For evaluation of the frequency of erythromycin induced clindamycin resistance, disk approximation test (D-test) was applied.Totally, 148 (29.6%) children were colonized by S. aureus. Out of 260 male, 94 (36.2%) and of 240 female, 54 (22.5%) cases were nasal carriers of S. aureus (P value = 0.001). Six (4.1%) of the 148 S. aureus isolated from children were MRSA strains. None of MRSA and methicillin susceptible S. aureus (MSSA) was resistant to vancomycin and clindamycin. Three of the 6 strains of MRSA and 7 (4.9%) of the 142 MSSA strains were resistant to erythromycin, and D-test was positive in all of them.We conclude that the rate of colonization by S. aureus is high in children attending day-care centers but colonization with MRSA is not common in our areas. Clindamycin or trimethoprim-sulfamethoxazol could be used in mild to moderataly severe diseases caused by CA-MRSA. However, if the CA-MRSA isolates are erythromycin resistant, D-test should be carried out for detection of inducible clindamycin resistance.

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

    PubMed

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

    2016-08-15

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

  10. Effect of United States buckwheat honey on antibiotic-resistant hospital acquired pathogens

    PubMed Central

    Hammond, Eric Nee-Armah; Duster, Megan; Musuuza, Jackson Ssentalo; Safdar, Nasia

    2016-01-01

    Introduction Due to an upsurge in antibiotic-resistant infections and lack of therapeutic options, new approaches are needed for treatment. Honey may be one such potential therapeutic option. We investigated the susceptibility of hospital acquired pathogens to four honeys from Wisconsin, United States, and then determined if the antibacterial effect of each honey against these pathogens is primarily due to the high sugar content. Methods Thirteen pathogens including: four Clostridium difficile, two Methicillin-resistant Staphylococcus aureus, two Pseudomonas aeruginosa, one Methicillin-Susceptible Staphylococcus aureus, two Vancomycin-resistance Enterococcus, one Enterococcus faecalis and one Klebsiella pneumoniae were exposed to 1-50% (w/v) four Wisconsin honeys and Artificial honey to determine their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the broth dilution method. Results Buckwheat honey predominantly exhibited a bactericidal mode of action against the tested pathogens, and this varied with each pathogen. C. difficile isolates were more sensitive to the Wisconsin buckwheat honey as compared to the other pathogens. Artificial honey at 50% (w/v) failed to kill any of the pathogens. The high sugar content of Wisconsin buckwheat honey is not the only factor responsible for its bactericidal activity. Conclusion Wisconsin buckwheat honey has the potential to be an important addition to therapeutic armamentarium against resistant pathogens and should be investigated further. PMID:28292167

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

    PubMed

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

    2015-04-08

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

  12. Comparative in vitro activity of oritavancin and other agents against methicillin-susceptible and methicillin-resistant Staphylococcus aureus.

    PubMed

    Sweeney, Debora; Shinabarger, Dean L; Arhin, Francis F; Belley, Adam; Moeck, Greg; Pillar, Chris M

    2017-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections constitute a threat to the public health due to their prevalence and associated mortality and morbidity. Several agents have been recently approved to treat MRSA skin infections including lipoglycopeptides (dalbavancin, oritavancin, and telavancin), ceftaroline, and tedizolid. This study compared the MIC, minimum bactericidal concentration (MBC), and time-kill of these agents alongside daptomycin, linezolid, and vancomycin against MRSA (n=15); meropenem, cefazolin, and nafcillin were also included against methicillin-susceptible S. aureus (MSSA [n=12]). MIC and MBC testing was conducted in accordance with Clinical and Laboratory Standards Institute guidelines, and time-kills were evaluated at multiples of the MIC and the free-drug maximum plasma concentration (fCmax) at both standard and high inoculum densities for a subset of MRSA (n=2) and MSSA (n=2). MRSA and MSSA were highly susceptible to all agents, with the lipoglycopeptides having the most potent activity by MIC50/90. All agents excluding tedizolid and linezolid were bactericidal by MBC for MRSA and MSSA, though dalbavancin and telavancin exhibited strain-specific bactericidal activity for MRSA. All agents excluding tedizolid and linezolid were bactericidal by time-kill at their respective fCmax against MRSA and MSSA at standard inoculum density, though oritavancin exhibited the most rapid bactericidal activity. Oritavancin and daptomycin at their respective fCmax maintained similar kill curves at high inoculum density. In contrast, the killing observed with other agents was typically reduced or slowed at high inoculum density. These data demonstrate the rapid bactericidal activity of oritavancin and daptomycin against S. aureus relative to other MRSA agents regardless of bacterial burden.

  13. Ventilator-associated pneumonia by Staphylococcus aureus. Comparison of methicillin-resistant and methicillin-sensitive episodes.

    PubMed

    Rello, J; Torres, A; Ricart, M; Valles, J; Gonzalez, J; Artigas, A; Rodriguez-Roisin, R

    1994-12-01

    All episodes of ventilator-associated pneumonia (VAP) caused by Staphylococcus aureus were prospectively analyzed for a 30-mo period. Methicillin-sensitive S. aureus (MSSA) was isolated in 38 episodes and methicillin-resistant S. aureus (MRSA) in 11 others. The two groups were similar regarding sex, severity of underlying diseases, prior surgery, and presence of renal failure, diabetes, cardiopathy, and coma. MRSA-infected persons were more likely to have received steroids before developing infection (relative risk [RR] = 3.45, 95% confidence interval [CI] = 1.38-8.59), to have been ventilated > 6 d (RR = 2.03, 95% CI = 1.36-3.03), to have been older than 25 yr (RR = 1.50, 95% CI = 1.09-2.06), and to have had preceding chronic obstructive pulmonary disease (RR = 2.76, 95% CI = 0.89-8.56) than MSSA-infected patients. MSSA-infected persons were more likely than MRSA-infected patients to have cranioencephalic trauma (RR = 1.94, 95% CI = 1.22-3.09). All patients with MRSA VAP had previously received antibiotics, compared with only 21.1% of those with MSSA infection (p < 0.000001). The incidence of empyema was similar in both groups; nevertheless, the presence of bacteremia and septic shock was more frequent in the MRSA group. Finally, mortality directly related to pneumonia was significantly higher among patients with MRSA episodes (RR = 20.72, 95% CI = 2.78-154.35). This analysis was repeated for monomicrobial episodes, and the difference remained statistically significant. We conclude that MRSA and MSSA strains infect patients with different demographic profiles; previous antibiotic therapy is the most important risk factor for developing MRSA infection.(ABSTRACT TRUNCATED AT 250 WORDS)

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

    PubMed

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

    2016-03-15

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

  15. Genotyping of coa and aroA Genes of Methicillin-Resistant Staphylococcus aureus Strains Isolated From Nasal Samples in Western Iran

    PubMed Central

    Mohajeri, Parviz; Azizkhani, Samira; Farahani, Abbas; Norozi, Baharak

    2016-01-01

    Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial pathogen frequently isolated in both hospital and community environments. Methicillin-resistant Staphylococcus aureus is considered a major nosocomial pathogen that causes severe morbidity and mortality. Objectives: The main objective of this study was to determine the genotypes of MRSA strains isolated from the nares of hospitalized and community patients in Kermanshah Hospital, western Iran, by PCR-restriction fragment length polymorphism (PCR-RFLP). Materials and Methods: Of 1387 patients, 1217 patients were screened for more than 48 hours after admission in hospital wards and 170 patients were screened in the hemodialysis unit of Kermanshah Hospital, which is the largest hospital in western Iran. S. aureus was identified by standard biochemical tests, including colonial morphology, production of coagulase, and DNase and the API20 Staph test. Methicillin-resistant Staphylococcus aureus was identified by the Oxacillin strip test. Results: In total, 258 S. aureus isolates were recovered from 1387 samples, of which 96 isolates were MRSA, 82 were hospital acquired, and 14 were community acquired. Digestion of the aro A gene revealed only one distinctive RFLP pattern in the 258 isolates. Conclusions: Methicillin-resistant Staphylococcus aureus is an increasingly common cause of nosocomial infections. Our results are in agreement with those of other studies reporting that a few specialized clones are responsible for most cases of MRSA nasal carriage. In this study, MRSA strains isolated from different wards of hospital were closely related when analyzed by coagulase gene typing. Identifying patients colonized with MRSA during hospitalization and rapidly typing them with these methods may facilitate detection of outbreaks and prevention of the spread of organisms in hospitals. PMID:27099680

  16. Assessment of methicillin and clindamycin resistance patterns in Staphylococcus aureus isolated from a tertiary hospital in Turkey.

    PubMed

    Tekin, Alicem; Dal, Tuba; Deveci, Ozcan; Tekin, Recep; Atmaca, Selahattin; Dayan, Saim

    2013-06-01

    In order to detect the methicillin susceptibility and determine the prevalence of constitutive and inducible clindamycin resistance in Staphylococcus aureus strains, a total of 254 S. aureus isolates, including 139 (54.7%) methicillin-sensitive and 115 (45.3%) methicillin-resistant, were tested for clindamycin and erythromycin by Kirby-Bauer disk diffusion method. The disk diffusion induction test or D-test was performed on erythromycin-resistant and clindamycin-sensitive strains using the disk diffusion method. The erythromycin-resistant and clindamycin-sensitive strains with a D-shaped zone around the clindamycin disk were considered positive for inducible clindamycin resistance. If a strain was found to be both erythromycin-resistant and clindamycin-resistant, it was considered to have constitutive clindamycin resistance. Overall, ten (3.9%) strains, including two methicillin-resistant S. aureus and eight methicillin-sensitive S. aureus, were found to be erythromycin-resistant and clindamycin-sensitive according to the disk diffusion method and all of these strains showed inducible clindamycin resistance by the D-test method. Constitutive clindamycin resistance was detected in 100 of all MRSA strains. In conclusion, the presence of inducible clindamycin-resistant strains may lead to clindamycin treatment failure in patients with S. aureus infection. The D-test method should be used for antimicrobial susceptibility testing of clindamycin.

  17. Characterization of methicillin resistant Staphylococcus aureus strains among inpatients and outpatients in a referral hospital in Tehran, Iran.

    PubMed

    Rahimi, Fateh; Shokoohizadeh, Leili

    2016-08-01

    Methicillin resistant Staphylococcus aureus is one of the most common causes of a variety of infections ranging from wound infections to urinary tract infections (UTI) in hospital and community. In this study during 3 years we characterized the antibiotic resistance patterns of 491 hospital acquired MRSA and community associated MRSA strains by the guidelines of clinical and laboratory standard institute. A combination of high resolution PhP typing method and SCCmec typing were used for clonal dissemination of isolates. Among all 491 MRSA strains, diverse PhP types consisting of 29 common types (CTs) and 4 single types (STs) and also 2 different SCCmec types (III and IVa) were detected. In addition, 18 CTs were common among CA- and HA-MRSA strains and the presence of all 4 STs was limited to HA-MRSA strains. All isolates were resistant to penicillin and high level resistance was observed against ciprofloxacin, erythromycin, tobramycin and kanamycin and the rate of resistance to most of the antibiotic tested among HA-MRSA was significantly higher than CA-MRSA isolates. Moreover, all isolates showed susceptibility to linezolid, vancomycin and quinupristin-dalfopristin and very low resistance to fusidic acid, nitrofurantoin and chloramphenicol were detected. Our findings illustrated the increasing rate of clonal dissemination and persistence of highly antibiotic resistant CA-MRSA strains in Tehran hospitals, and also indicated the important role of the hospitals as the reservoir of MRSA strains.

  18. 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.

  19. Carriage of Methicillin-Resistant Staphylococcus aureus by Wild Urban Norway Rats (Rattus norvegicus)

    PubMed Central

    Himsworth, Chelsea G.; Miller, Ruth R.; Montoya, Vincent; Hoang, Linda; Romney, Marc G.; Al-Rawahi, Ghada N.; Kerr, Thomas; Jardine, Claire M.; Patrick, David M.; Tang, Patrick; Weese, J. Scott

    2014-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of multi-drug-resistant infections in people, particularly indigent populations. MRSA can be transmitted between people and domestic animals, but the potential for transmission between people and commensal pests, particularly rodents, had not been investigated. The objective of this study was to identify the presence and characterize the ecology of MRSA in rats (Rattus spp.) from in an impoverished, inner-city neighborhood. Oropharyngeal swabs were collected from rats trapped in 33 city blocks and one location within the adjacent port. Bacterial culture was performed and MRSA isolates were characterized using a variety of methods, including whole-genome sequencing (WGS). The ecology of MRSA in rats was described using phylogenetic analysis, geospatial analysis, and generalized linear mixed models. MRSA was identified 22 of 637 (3.5%) rats tested, although prevalence varied from 0 – 50% among blocks. Isolates belonged to 4 clusters according to WGS, with the largest cluster (n = 10) containing isolates that were genetically indistinguishable from community-acquired USA300 MRSA strains isolated from people within the study area. MRSA strains demonstrated both geographic clustering and dispersion. The odds of an individual rat carrying MRSA increased with increased body fat (OR = 2.53, 95% CI = 1.33 – 4.82), and in the winter (OR = 5.29, 95% CI = 1.04 – 26.85) and spring (OR = 5.50, 95% CI = 1.10 – 27.58) compared to the fall. The results show that urban rats carried the same MRSA lineages occurring in local human and/or animal populations, supporting recent transmission from external sources. MRSA carriage was influenced by season, most likely as a result of temporal variation in rat behavior and rat-human interactions. PMID:24498421

  20. Carriage of methicillin-resistant Staphylococcus aureus by wild urban Norway rats (Rattus norvegicus).

    PubMed

    Himsworth, Chelsea G; Miller, Ruth R; Montoya, Vincent; Hoang, Linda; Romney, Marc G; Al-Rawahi, Ghada N; Kerr, Thomas; Jardine, Claire M; Patrick, David M; Tang, Patrick; Weese, J Scott

    2014-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of multi-drug-resistant infections in people, particularly indigent populations. MRSA can be transmitted between people and domestic animals, but the potential for transmission between people and commensal pests, particularly rodents, had not been investigated. The objective of this study was to identify the presence and characterize the ecology of MRSA in rats (Rattus spp.) from in an impoverished, inner-city neighborhood. Oropharyngeal swabs were collected from rats trapped in 33 city blocks and one location within the adjacent port. Bacterial culture was performed and MRSA isolates were characterized using a variety of methods, including whole-genome sequencing (WGS). The ecology of MRSA in rats was described using phylogenetic analysis, geospatial analysis, and generalized linear mixed models. MRSA was identified 22 of 637 (3.5%) rats tested, although prevalence varied from 0 - 50% among blocks. Isolates belonged to 4 clusters according to WGS, with the largest cluster (n = 10) containing isolates that were genetically indistinguishable from community-acquired USA300 MRSA strains isolated from people within the study area. MRSA strains demonstrated both geographic clustering and dispersion. The odds of an individual rat carrying MRSA increased with increased body fat (OR = 2.53, 95% CI = 1.33-4.82), and in the winter (OR = 5.29, 95% CI = 1.04-26.85) and spring (OR = 5.50, 95% CI = 1.10-27.58) compared to the fall. The results show that urban rats carried the same MRSA lineages occurring in local human and/or animal populations, supporting recent transmission from external sources. MRSA carriage was influenced by season, most likely as a result of temporal variation in rat behavior and rat-human interactions.

  1. Comparison of Culture-Based Methods for Identification of Colonization with Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus in the Context of Cocolonization

    PubMed Central

    Hu, Baofeng; Carroll, Karen C.; Bilker, Warren B.; Tolomeo, Pam; Cluzet, Valerie C.; Baron, Patrick; Ferguson, Jacqueline M.; Morris, Daniel O.; Rankin, Shelley C.; Lautenbach, Ebbing

    2016-01-01

    Two screening methods to detect staphylococcal colonization in humans were compared. Direct plating to CHROMagar (BD Diagnostics) was compared to a broth preenrichment followed by plating to Baird-Parker agar. The broth-enrichment method was comparable to CHROMagar for methicillin-resistant Staphylococcus aureas (MRSA) detection, but the enrichment method was optimum for recovery of coagulase-positive Staphylococcus spp. PMID:27122377

  2. Comparison of Culture-Based Methods for Identification of Colonization with Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus in the Context of Cocolonization.

    PubMed

    Davis, Meghan F; Hu, Baofeng; Carroll, Karen C; Bilker, Warren B; Tolomeo, Pam; Cluzet, Valerie C; Baron, Patrick; Ferguson, Jacqueline M; Morris, Daniel O; Rankin, Shelley C; Lautenbach, Ebbing; Nachamkin, Irving

    2016-07-01

    Two screening methods to detect staphylococcal colonization in humans were compared. Direct plating to CHROMagar (BD Diagnostics) was compared to a broth preenrichment followed by plating to Baird-Parker agar. The broth-enrichment method was comparable to CHROMagar for methicillin-resistant Staphylococcus aureas (MRSA) detection, but the enrichment method was optimum for recovery of coagulase-positive Staphylococcus spp.

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

    PubMed

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

    2014-09-01

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

  4. 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.

  5. [A simple method for differentiating methicillin-resistant, penicillinase-positive and -negative staphylococci by agardiffusion test (author's transl)].

    PubMed

    Hirschl, A; Stanek, G; Rotter, M

    1980-01-01

    Coagulase-positive staphylococci (41 methicillin-resistant strains, 28 penicillinase-positive and 12 penicillinase-negative strains) were tested against most types of penicillines commercially available on the Austrian market using both broth-dilution test (incubated during 48 hours at 35 degrees C) and agardiffusion tests (incubated during 24 hours at 30, 35 and 37 degrees C) employing Mueller-Hinton-broth and -agar, respectively, in order to find out the most convenient way of detecting methicillin-resistant strains. Consecutively, the conclusions drawn from these experiments were verified for tests on Isosensitest-agar (Oxoid). It was demonstrated that methicillin-resistant strains could be detected easily with discs of methicillin and oxacillin at 30 degrees C (Fig. 1). At 35 degrees C this was nearly as easily possible for methicillin but oxacillin discs had to be used at amounts of 1 microgram instead of 5 microgram. Excepting penicillin G-discs with the other penicillines differing numbers of methicillin-resistant strains would have been missed at 37 degrees C (Fig. 1, 2). Only with discs containing 6 microgram penicillin G methicillin-resistant strains were unequivocally identifiable in the agardiffusion test at all 3 incubation-temperatures (Fig. 3), the largest inhibition zone diameter being 12 mm. Penicillinase-positive but methicillin-sensitive strains always produced larger inhibition zones up to 30 mm. From these strains again penicillinase-negative strains were equally well distinguishable by much larger inhibition zones. So, the conclusion was drawn that on Mueller-Hinton agar one disc loaded with 6 microgram of penicillin G allows proper distinction not only of methicillin-resistant and -sensitive but also of penicillinase-positive and -negative strains of staphylococci. On Isosensitest-agar this is true for an incubation-temperature of 35 but not 37 degrees C (Tab. 1).

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

    PubMed Central

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

    2002-01-01

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

  8. [Effectiveness of alcoholic hand disinfectants against methicillin resistant Staphylococcus aureus].

    PubMed

    Kampf, G; Jarosch, R; Rüden, H

    1997-03-01

    In order to determine the efficacy of hand disinfectants based on alcohol against three MRSA strains and 3 methicillin-susceptible S. aureus strains (MSSA), 1-propanol (60%) as well as Sterillium and Spitaderm were investigated in the quantitative suspension test at various dilutions and reactions times (15, 30 and 60s). All undiluted disinfectants revealed reduction factors > 6 against MRSA and MSSA after 30s. Diluted disinfectants (50%) were significantly less effective against MRSA at short reaction times (15 s) (p < 0.05). Sterillium in a dilution of 50% did not reach 5 reduction factors against either MRSA or MSSA after 30 s. The impact of an appropriate use of hand disinfectants in order to break chains of infections with MRSA is obvious.

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

    PubMed

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

    2009-06-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  12. 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.

  13. 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

  14. 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.

  15. 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.

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

    PubMed

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

    2016-03-01

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

  17. 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.

  18. 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.

  19. 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

  20. Staphylococci isolated from carriage sites and infected sites of dogs as a reservoir of multidrug resistance and methicillin resistance.

    PubMed

    Garbacz, Katarzyna; Żarnowska, Sabina; Piechowicz, Lidia; Haras, Krystyna

    2013-02-01

    The aim of this study was to compare the spread of multidrug-resistant (MDR) and methicillin-resistant (MR) staphylococci in healthy dogs and in dogs with evident symptoms of infection. The samples from 172 healthy and 197 infected dogs were examined. The staphylococci were identified with conventional methods and by means of the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method (MboI). Susceptibility to 15 antibiotics from 10 different antimicrobial classes was tested. Resistance to methicillin was confirmed by the presence of Staphylococcus aureus mecA and S. sciuri mecA genes. Multidrug resistance was defined as resistance to three or more antimicrobial classes. The oral mucosa to be the most frequent site of staphylococcal colonization (55.8 %), followed by nasal cavity (44.2 %), and anus (32.6 %). The prevalence of MDR staphylococci in infected dogs was significantly higher than in the healthy animals (74/137 vs. 34/95, P = 0.006). The MR strains of S. pseudintermedius (2.9 %) originated solely from infected dogs. In contrast, the MR coagulase-negative strains (7.4 %) were isolated solely from healthy dogs. S. aureus strains originated from nasal swabs, MRSA strains were not isolated. MDR staphylococci and MR S. pseudintermedius are more common among infected dogs, but coagulase-negative staphylococci (mostly S. sciuri) seem to be a reservoir of methicillin resistance in healthy dogs.

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Clinical significance of methicillin-resistant coagulase-negative staphylococci obtained from sterile specimens.

    PubMed

    Tashiro, Masato; Izumikawa, Koichi; Ashizawa, Nobuyuki; Narukawa, Munetoshi; Yamamoto, Yoshihiro

    2015-01-01

    Distinguishing true coagulase-negative staphylococci bacteremia from contamination remains a challenge. We conducted a retrospective analysis of 183 patients with methicillin-resistant coagulase-negative staphylococci (MR-CoNS)-positive and methicillin-resistant Staphylococcus aureus-positive cultures obtained from sterile sites such as blood, synovial fluid, ascitic fluid, and cerebrospinal fluid. Of the 209 MR-CoNS isolates, 83 (39.7%) were considered infection associated, and 126 (60.3%) were considered contamination. MR-CoNS isolates cultured from synovial fluid were more likely to be infection associated (P = 0.009). The median interval from insertion of a central venous catheter to onset of infection tended to be longer in MR-CoNS infection cases than in methicillin-resistant S. aureus infection cases (41 days versus 14 days, P = 0.055). In conclusion, our results suggest that the proportion of cases of true MR-CoNS infection may be higher than previously reported.

  14. Methicillin-resistant Staphylococcus aureus Bacterial Nitric-oxide Synthase Affects Antibiotic Sensitivity and Skin Abscess Development*

    PubMed Central

    van Sorge, Nina M.; Beasley, Federico C.; Gusarov, Ivan; Gonzalez, David J.; von Köckritz-Blickwede, Maren; Anik, Sabina; Borkowski, Andrew W.; Dorrestein, Pieter C.; Nudler, Evgeny; Nizet, Victor

    2013-01-01

    Staphylococcus aureus infections present an enormous global health concern complicated by an alarming increase in antibiotic resistance. S. aureus is among the few bacterial species that express nitric-oxide synthase (bNOS) and thus can catalyze NO production from l-arginine. Here we generate an isogenic bNOS-deficient mutant in the epidemic community-acquired methicillin-resistant S. aureus (MRSA) USA300 clone to study its contribution to virulence and antibiotic susceptibility. Loss of bNOS increased MRSA susceptibility to reactive oxygen species and host cathelicidin antimicrobial peptides, which correlated with increased MRSA killing by human neutrophils and within neutrophil extracellular traps. bNOS also promoted resistance to the pharmaceutical antibiotics that act on the cell envelope such as vancomycin and daptomycin. Surprisingly, bNOS-deficient strains gained resistance to aminoglycosides, suggesting that the role of bNOS in antibiotic susceptibility is more complex than previously observed in Bacillus species. Finally, the MRSA bNOS mutant showed reduced virulence with decreased survival and smaller abscess generation in a mouse subcutaneous infection model. Together, these data indicate that bNOS contributes to MRSA innate immune and antibiotic resistance phenotypes. Future development of specific bNOS inhibitors could be an attractive option to simultaneously reduce MRSA pathology and enhance its susceptibility to commonly used antibiotics. PMID:23322784

  15. Acquired resistance of Mycobacterium tuberculosis to bedaquiline.

    PubMed

    Andries, Koen; Villellas, Cristina; Coeck, Nele; Thys, Kim; Gevers, Tom; Vranckx, Luc; Lounis, Nacer; de Jong, Bouke C; Koul, Anil

    2014-01-01

    Bedaquiline (BDQ), an ATP synthase inhibitor, is the first drug to be approved for treatment of multi-drug resistant tuberculosis in decades. In vitro resistance to BDQ was previously shown to be due to target-based mutations. Here we report that non-target based resistance to BDQ, and cross-resistance to clofazimine (CFZ), is due to mutations in Rv0678, a transcriptional repressor of the genes encoding the MmpS5-MmpL5 efflux pump. Efflux-based resistance was identified in paired isolates from patients treated with BDQ, as well as in mice, in which it was confirmed to decrease bactericidal efficacy. The efflux inhibitors verapamil and reserpine decreased the minimum inhibitory concentrations of BDQ and CFZ in vitro, but verapamil failed to increase the bactericidal effect of BDQ in mice and was unable to reverse efflux-based resistance in vivo. Cross-resistance between BDQ and CFZ may have important clinical implications.

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

    PubMed Central

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

    2015-01-01

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

  17. Prevalence of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus in Retail Ready-to-Eat Foods in China

    PubMed Central

    Yang, Xiaojuan; Zhang, Jumei; Yu, Shubo; Wu, Qingping; Guo, Weipeng; Huang, Jiahui; Cai, Shuzhen

    2016-01-01

    Staphylococcus aureus, particularly methicillin-resistant S.aureus (MRSA), is a life-threatening pathogen in humans, and its presence in food is a public health concern. MRSA has been identified in foods in China, but little information is available regarding MRSA in ready-to-eat (RTE) foods. We aimed to investigate the prevalence of S. aureus and MRSA in Chinese retail RTE foods. All isolated S. aureus were tested for antimicrobial susceptibility, and MRSA isolates were further characterized by multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) typing. Of the 550 RTE foods collected from 2011 to 2014, 69 (12.5%) were positive for S. aureus. Contamination levels were mostly in the range of 0.3–10 most probable number (MPN)/g, with five samples exceeding 10 MPN/g. Of the 69 S. aureus isolates, seven were identified as MRSA by cefoxitin disc diffusion test. Six isolates were mecA-positive, while no mecC-positive isolates were identified. In total, 75.8% (47/62) of the methicillin-susceptible S. aureus isolates and all of the MRSA isolates were resistant to three or more antibiotics. Amongst the MRSA isolates, four were identified as community-acquired strains (ST59-MRSA-IVa (n = 2), ST338-MRSA-V, ST1-MRSA-V), while one was a livestock-associated strain (ST9, harboring an unreported SCCmec type 2C2). One novel sequence type was identified (ST3239), the SCCmec gene of which could not be typed. Overall, our findings showed that Chinese retail RTE foods are likely vehicles for transmission of multidrug-resistant S. aureus and MRSA lineages. This is a serious public health risk and highlights the need to implement good hygiene practices. PMID:27375562

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

    Cercenado, Emilia; Morosini, María Isabel

    2014-03-01

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

  20. 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

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

    SciTech Connect

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

    2010-01-01

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

  2. Structure-function studies of the staphylococcal methicillin resistance antirepressor MecR2.

    PubMed

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

    2013-07-19

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

  3. Evolution and Molecular Characterization of Methicillin-Resistant Staphylococcus aureus Epidemic and Sporadic Clones in Cordoba, Argentina

    PubMed Central

    Sola, Claudia; Cortes, Paulo; Saka, Hector A.; Vindel, Ana; Bocco, José Luis

    2006-01-01

    Since 1999, a new, epidemic, methicillin-resistant Staphylococcus aureus (MRSA) strain, named the “Cordobes clone,” has emerged in Argentina and coexists with the pandemic Brazilian clone. The purpose of this study was to determine the stability over time of the new clone and to investigate its evolutionary relationship with epidemic international MRSA lineages and with other MRSA and methicillin-susceptible S. aureus (MSSA) major clones distributed in this region. One hundred three MRSA isolates recovered in 2001 from Cordoba, Argentina, hospitals and 31 MSSA strains collected from 1999 to 2002 were analyzed by their antibiotic resistance patterns, phage typing, and pulsed-field gel electrophoresis. Additionally, representative members of most MRSA defined genotypes (A, B, C, E, K, and I) were characterized by multilocus sequence typing (MLST) and spaA and SCCmec typing. The most prevalent MSSA pulsotypes were also analyzed by MLST. Our results support the displacement of the Brazilian clone (sequence type [ST] 239, spaA type WGKAOMQ, SCCmec type IIIA) by the Cordobes clone (ST5, spaA type TIMEMDMGMGMK, SCCmec type I) in the hospital environment. MRSA and MSSA isolates shared only ST5. The data support the origin of the Cordobes clone as a member of a lineage that includes the pediatric and New York/Japan international clones and that is genetically related to the British EMRSA-3 strain. Interestingly, the pediatric clone, isolated from most community-acquired infections in Cordoba, was characterized by ST100, a single-locus variant of ST5 and a new variant of SCCmec type related to SCCmec type IVc. PMID:16390969

  4. 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

  5. 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

  6. 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.

  7. Reliability of the Kirby-Bauer disc diffusion method for detecting methicillin-resistant strains of Staphylococcus aureus.

    PubMed

    Drew, W L; Barry, A L; O'Toole, R; Sherris, J C

    1972-08-01

    The resistance of Staphylococcus aureus to methicillin and related drugs can be reliably determined by using the Kirby-Bauer method of susceptibility testing if the incubation temperature is 35 C or below, but resistance may be missed at 37 C. The 1-mug discs of oxacillin and nafcillin or the 5-mug discs of methicillin may be used for this purpose but not the 1-mug discs of cloxacillin. The latter fail to discriminate between sensitive and resistant staphylococci by zone measurement; some resistant strains of staphylococci may show larger zones of inhibition than sensitive strains. Stability of these antibiotic-containing discs was studied under conditions of temperature and humidity variation that might be encountered in a clinical laboratory refrigerator. Oxacillin discs were the most stable and are to be preferred for susceptibility testing. Nafcillin discs were less stable, and methicillin discs lose their potency rapidly unless carefully stored in a refrigerator with a desiccant.

  8. 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.

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

    PubMed Central

    Thiébaut, Anne C. M.; Lawrence, Christine; Bouchiat, Coralie; Herrmann, Jean-Louis; Salomon, Jérôme

    2015-01-01

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

  10. 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.

  11. Biocide and antimicrobial susceptibility of methicillin-resistant staphylococcal isolates from horses.

    PubMed

    Couto, Natacha; Belas, Adriana; Tilley, Paula; Couto, Isabel; Gama, Luís T; Kadlec, Kristina; Schwarz, Stefan; Pomba, Constança

    2013-09-27

    The aim of this study was to evaluate the biocide and antimicrobial susceptibility of methicillin-resistant staphylococcal isolates from horses. Fourteen methicillin-resistant staphylococci (MRS) were subjected to an extensive genotype characterization, including SCCmec, dru, spa, PFGE and MLST typing. Antimicrobial susceptibility testing was performed and resistance genes were detected by PCR. Minimum bactericidal concentrations (MBCs) of four biocides [chlorhexidine acetate (CHA), benzalkonium chloride (BAC), triclosan (TCL) and glutaraldehyde (GLA)] were determined following the recommendations of document NF EN 1040. The presence of qac and sh-fabI genes was investigated by PCR. Several antimicrobial resistance patterns and genes were detected. When MRS strains were exposed for a longer period of time, a lower concentration of the biocide was needed to achieve lethality. TCL had the lowest MBC values. All MBC values were lower than the recommended in-use concentrations for veterinary medicine. S. haemolyticus and S. cohnii subsp. cohnii carried plasmid-borne qacA and sh-fabI or qacB and a qacH-like genes, respectively. Biocides appear to be a reliable antiseptic option against MRS, since even in the presence of bacterial efflux mechanisms, the recommended concentration is much higher than the in vitro MBC.

  12. 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.

  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. Comparison of Multi-Drug Resistant Environmental Methicillin-Resistant Staphylococcus aureus Isolated from Recreational Beaches and High Touch Surfaces in Built Environments.

    PubMed

    Roberts, Marilyn C; Soge, Olusegun O; No, David

    2013-01-01

    Over the last decade community-acquired methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major cause of disease in the general population with no health care exposure or known classical risk factors for MRSA infections. The potential community reservoirs have not been well defined though certain strains such as ST398 and USA300 have been well studied in some settings. MRSA has been isolated from recreational beaches, high-touch surfaces in homes, universities, and other community environmental surfaces. However, in most cases the strains were not characterized to determine if they are related to community-acquired or hospital-acquired clinical strains. We compared 55 environmental MRSA from 805 samples including sand, fresh, and marine water samples from local marine and fresh water recreational beaches (n = 296), high touch surfaces on the University of Washington campus (n = 294), surfaces in UW undergraduate housing (n = 85), and the local community (n = 130). Eleven USA300, representing 20% of the isolates, were found on the UW campus surfaces, student housing surfaces, and on the community surfaces but not in the recreational beach samples from the Northwest USA. Similarly, the predominant animal ST133 was found in the recreational beach samples but not in the high touch surface samples. All USA300 isolates were multi-drug resistant carrying two to six different antibiotic resistance genes coding for kanamycin, macrolides and/or macrolides-lincosamides-streptogramin B, and tetracycline, with the majority (72%) carrying four to six different antibiotic resistance genes. A surprising 98% of the 55 MRSA isolates were resistant to other classes of antibiotics and most likely represent reservoirs for these genes in the environment.

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

    PubMed

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

    2016-08-31

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

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

    PubMed Central

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

    2015-01-01

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

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. [Methicillin-resistant Staphylococcus aureus in pig breeders and cattle breeders].

    PubMed

    Vandenbroucke-Grauls, C M J E; Beaujean, D J M A

    2006-08-05

    It was recently observed that pig breeders in The Netherlands often carry methicillin-resistant Staphylococus aureus (MRSA). These MRSA strains are related to MRSA strains found in pigs. A case-control study showed that not only pig breeders but also cattle breeders are at risk of carrying MRSA. It is advised to keep pig breeders, if they are admitted to a hospital, in isolation until surveillance cultures are proven negative. This also applies to veterinarians and slaughterhouse personnel. For cattle breeders screening without isolation on admission to a hospital is sufficient.

  8. A Research-Inspired Laboratory Sequence Investigating Acquired Drug Resistance

    ERIC Educational Resources Information Center

    Taylor, Elizabeth Vogel; Fortune, Jennifer A.; Drennan, Catherine L.

    2010-01-01

    Here, we present a six-session laboratory exercise designed to introduce students to standard biochemical techniques in the context of investigating a high impact research topic, acquired resistance to the cancer drug Gleevec. Students express a Gleevec-resistant mutant of the Abelson tyrosine kinase domain, the active domain of an oncogenic…

  9. Genomic Basis for Methicillin Resistance in Staphylococcus aureus

    PubMed Central

    Ito, Teruyo; Tsubakishita, Sae; Sasaki, Takashi; Takeuchi, Fumihiko; Morimoto, Yuh; Katayama, Yuki; Matsuo, Miki; Kuwahara-Arai, Kyoko; Hishinuma, Tomomi; Baba, Tadashi

    2013-01-01

    Since the discovery of the first strain in 1961 in England, MRSA, the most notorious multidrug-resistant hospital pathogen, has spread all over the world. MRSA repeatedly turned down the challenges by number of chemotherapeutics, the fruits of modern organic chemistry. Now, we are in short of effective therapeutic agents against MRSA prevailing among immuno-compromised patients in the hospital. On top of this, we recently became aware of the rise of diverse clones of MRSA, some of which have increased pathogenic potential compared to the classical hospital-associated MRSA, and the others from veterinary sources. They increased rapidly in the community, and started menacing otherwise healthy individuals by causing unexpected acute infection. This review is intended to provide a whole picture of MRSA based on its genetic makeup as a versatile pathogen and our tenacious colonizer. PMID:24265961

  10. 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.

  11. Detection and characterization of methicillin-resistant Staphylococcus pseudintermedius in healthy dogs in La Rioja, Spain.

    PubMed

    Gómez-Sanz, Elena; Torres, Carmen; Lozano, Carmen; Sáenz, Yolanda; Zarazaga, Myriam

    2011-09-01

    The objective was to identify the methicillin-resistant coagulase-positive staphylococci (MRCoPS) nasal carriage rate of healthy dogs in La Rioja (Spain) and to characterize the recovered isolates by different molecular techniques. Nasal samples from 196 dogs were obtained (98 household-dogs, 98 pound-dogs). Isolates were identified and characterized by spa-, SCCmec- and MLST-typing, SmaI-PFGE, antimicrobial susceptibility, determination of antimicrobial resistance and toxin genes profiling. S. pseudintermedius was the only species recovered. Nine methicillin-resistant S. pseudintermedius (MRSP) were obtained from 9 of 196 sampled dogs (8% pound-dogs, 1% household-dogs). MRSP isolates were typed (MLST/PFGE/spa/SCCmec) as: ST71/A/t02/II-III (7 isolates), ST92/C/t06/V (1 isolate), and ST26/B/non-typable/non-typable (1 isolate). All MRSP were resistant to [resistance gene/number isolates]: β-lactams [mecA+blaZ/9], tetracycline [tet(K)/7, tet(M)/2], macrolides and lincosamides [erm(B)/9], aminoglycosides [aacA-aphD+aadE+aphA-3/9], and co-trimoxazol [dfr(G)/9]. Eight MRSP isolates showed also resistance to fluoroquinolones and amino acid changes in GyrA [Ser84Leu+Glu714Lys, 7 isolates; Ser84Leu, 1 isolate] and GrlA [Ser80Ile, 8 isolates] proteins were detected. The remaining isolate was chloramphenicol resistant and harboured cat(pC221) gene. All MRSP isolates harboured the aadE-sat4-aphA-3 multiresistance-gene-cluster linked to erm(B) gene as well as the siet, si-ent and lukS/F-I toxin genes. MRSP is a moderately common (4.6%) colonizer of healthy dogs in Spain. A major MRSP lineage (ST71) was detected and its future evolution should be tracked.

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

    PubMed

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

    2016-03-01

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

  13. Structural basis for the beta lactam resistance of PBP2a from methicillin-resistant Staphylococcus aureus.

    PubMed

    Lim, Daniel; Strynadka, Natalie C J

    2002-11-01

    The multiple antibiotic resistance of methicillin-resistant strains of Staphylococcus aureus (MRSA) has become a major clinical problem worldwide. The key determinant of the broad-spectrum beta-lactam resistance in MRSA strains is the penicillin-binding protein 2a (PBP2a). Because of its low affinity for beta-lactams, PBP2a provides transpeptidase activity to allow cell wall synthesis at beta-lactam concentrations that inhibit the beta-lactam-sensitive PBPs normally produced by S. aureus. The crystal structure of a soluble derivative of PBP2a has been determined to 1.8 A resolution and provides the highest resolution structure for a high molecular mass PBP. Additionally, structures of the acyl-PBP complexes of PBP2a with nitrocefin, penicillin G and methicillin allow, for the first time, a comparison of an apo and acylated resistant PBP. An analysis of the PBP2a active site in these forms reveals the structural basis of its resistance and identifies features in newly developed beta-lactams that are likely important for high affinity binding.

  14. 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.

  15. The evolution of resistance through costly acquired immunity.

    PubMed Central

    Boots, Michael; Bowers, Roger G.

    2004-01-01

    We examine the evolutionary dynamics of resistance to parasites through acquired immunity. Resistance can be achieved through the innate mechanisms of avoidance of infection and reduced pathogenicity once infected, through recovery from infection and through remaining immune to infection: acquired immunity. We assume that each of these mechanisms is costly to the host and find that the evolutionary dynamics of innate immunity in hosts that also have acquired immunity are quantitatively the same as in hosts that possess only innate immunity. However, compared with resistance through avoidance or recovery, there is less likely to be polymorphism in the length of acquired immunity within populations. Long-lived organisms that can recover at intermediate rates faced with fast-transmitting pathogens that cause intermediate pathogenicity (mortality of infected individuals) are most likely to evolve long-lived acquired immunity. Our work emphasizes that because whether or not acquired immunity is beneficial depends on the characteristics of the disease, organisms may be selected to only develop acquired immunity to some of the diseases that they encounter. PMID:15209105

  16. Clonality and Antimicrobial Susceptibility of Staphylococcus aureus and Methicillin-Resistant S. aureus Isolates from Food Animals and Other Animals

    PubMed Central

    Chow, Kin-Hung; Lai, Eileen L.; Law, Pierra Y. T.; Chan, Pui-Ying; Ho, Alex Y. M.; Ng, Tak-Keung; Yam, Wing-Cheong

    2012-01-01

    Out of 3,081 animals studied, 24.9% of pigs, 4.7% of chickens, 6.3% of dogs, 10.5% of cats, and 7.1% of rodents were Staphylococcus aureus positive. Prevalence of methicillin-resistant S. aureus (MRSA) was high in pigs (animals, 21.3%; batches, 46.5%), with all MRSA isolates and most methicillin-sensitive S. aureus isolates belonging to clonal complex 9 (CC9) and being multidrug resistant. The predominant S. aureus CCs among dog and cat isolates were similar. Among rodent isolates, CC398 predominated, with spa t034 the most frequent spa type detected. PMID:22895044

  17. Clonality and antimicrobial susceptibility of Staphylococcus aureus and methicillin-resistant S. aureus isolates from food animals and other animals.

    PubMed

    Ho, Pak-Leung; Chow, Kin-Hung; Lai, Eileen L; Law, Pierra Y T; Chan, Pui-Ying; Ho, Alex Y M; Ng, Tak-Keung; Yam, Wing-Cheong

    2012-11-01

    Out of 3,081 animals studied, 24.9% of pigs, 4.7% of chickens, 6.3% of dogs, 10.5% of cats, and 7.1% of rodents were Staphylococcus aureus positive. Prevalence of methicillin-resistant S. aureus (MRSA) was high in pigs (animals, 21.3%; batches, 46.5%), with all MRSA isolates and most methicillin-sensitive S. aureus isolates belonging to clonal complex 9 (CC9) and being multidrug resistant. The predominant S. aureus CCs among dog and cat isolates were similar. Among rodent isolates, CC398 predominated, with spa t034 the most frequent spa type detected.

  18. Antibacterial activity of extracellular compounds produced by a Pseudomonas strain against methicillin-resistant Staphylococcus aureus (MRSA) strains

    PubMed Central

    2013-01-01

    Background The emergence of multidrug-resistant bacteria is a world health problem. Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) strains, is one of the most important human pathogens associated with hospital and community-acquired infections. The aim of this work was to evaluate the antibacterial activity of a Pseudomonas aeruginosa-derived compound against MRSA strains. Methods Thirty clinical MRSA strains were isolated, and three standard MRSA strains were evaluated. The extracellular compounds were purified by vacuum liquid chromatography. Evaluation of antibacterial activity was performed by agar diffusion technique, determination of the minimal inhibitory concentration, curve of growth and viability and scanning electron microscopy. Interaction of an extracellular compound with silver nanoparticle was studied to evaluate antibacterial effect. Results The F3 (ethyl acetate) and F3d (dichloromethane- ethyl acetate) fractions demonstrated antibacterial activity against the MRSA strains. Phenazine-1-carboxamide was identified and purified from the F3d fraction and demonstrated slight antibacterial activity against MRSA, and synergic effect when combined with silver nanoparticles produced by Fusarium oxysporum. Organohalogen compound was purified from this fraction showing high antibacterial effect. Using scanning electron microscopy, we show that the F3d fraction caused morphological changes to the cell wall of the MRSA strains. Conclusions These results suggest that P. aeruginosa-produced compounds such as phenazines have inhibitory effects against MRSA and may be a good alternative treatment to control infections caused by MRSA. PMID:23773484

  19. Sanitary status and incidence of methicillin-resistant Staphylococcus aureus and Clostridium difficile within Canadian hotel rooms.

    PubMed

    Xu, Changyun; Weese, Scott J; Namvar, Azadeh; Warriner, Keith

    2015-04-01

    The study described in this article aimed at establishing a baseline assessment of the sanitary status of ice and guest rooms within Canadian hotels. Collectively, 54 hotel rooms belonging to six different national chains were sampled. High-contact surfaces (comforter, alarm clock, bedside lamp, TV remote, bathroom countertop, faucet, and toilet seat) were sampled using adenosine triphosphate (ATP) swabs and replicate organism detection and counting plates. ATP swab readings ranged from 2.12 to 4.42 log relative light units. Coliforms were recovered from 36% of surfaces with high prevalence being recovered from the comforter, TV remote, bathroom countertop, faucet, and toilet seat. Oxacillin-resistant bacteria were recovered from 19% of surfaces with 46% of isolates confirmed as methicillin-resistant Staphylococcus aureus. Two toxigenic Clostridium difficile isolates were recovered in the course of the study. Collectively, 24% of the ice samples harbored coliforms with a single sample testing positive for E. coli. The authors' study demonstrates that hotel rooms represent a potential source of community-acquired infections and the need for enhanced sanitation practices.

  20. Molecular Types of Methicillin-Resistant Staphylococcus aureus and Methicillin-Sensitive S. aureus Strains Causing Skin and Soft Tissue Infections and Nasal Colonization, Identified in Community Health Centers in New York City

    PubMed Central

    Pardos de la Gandara, Maria; Raygoza Garay, Juan Antonio; Mwangi, Michael; Tobin, Jonathan N.; Tsang, Amanda; Khalida, Chamanara; D'Orazio, Brianna; Kost, Rhonda G.; Leinberger-Jabari, Andrea; Coffran, Cameron; Evering, Teresa H.; Coller, Barry S.; Balachandra, Shirish; Urban, Tracie; Parola, Claude; Salvato, Scott; Jenks, Nancy; Wu, Daren; Burgess, Rhonda; Chung, Marilyn; de Lencastre, Herminia

    2015-01-01

    In November 2011, The Rockefeller University Center for Clinical and Translational Science (CCTS), the Laboratory of Microbiology and Infectious Diseases, and Clinical Directors Network (CDN) launched a research and learning collaborative project with six community health centers in the New York City metropolitan area to determine the nature (clonal type) of community-acquired Staphylococcus aureus strains causing skin and soft tissue infections (SSTIs). Between November 2011 and March 2013, wound and nasal samples from 129 patients with active SSTIs suspicious for S. aureus were collected and characterized by molecular typing techniques. In 63 of 129 patients, the skin wounds were infected by S. aureus: methicillin-resistant S. aureus (MRSA) was recovered from 39 wounds and methicillin-sensitive S. aureus (MSSA) was recovered from 24. Most—46 of the 63–wound isolates belonged to the CC8/Panton-Valentine leukocidin-positive (PVL+) group of S. aureus clone USA300: 34 of these strains were MRSA and 12 were MSSA. Of the 63 patients with S. aureus infections, 30 were also colonized by S. aureus in the nares: 16 of the colonizing isolates were MRSA, and 14 were MSSA, and the majority of the colonizing isolates belonged to the USA300 clonal group. In most cases (70%), the colonizing isolate belonged to the same clonal type as the strain involved with the infection. In three of the patients, the identity of invasive and colonizing MRSA isolates was further documented by whole-genome sequencing. PMID:26063853

  1. Molecular Types of Methicillin-Resistant Staphylococcus aureus and Methicillin-Sensitive S. aureus Strains Causing Skin and Soft Tissue Infections and Nasal Colonization, Identified in Community Health Centers in New York City.

    PubMed

    Pardos de la Gandara, Maria; Raygoza Garay, Juan Antonio; Mwangi, Michael; Tobin, Jonathan N; Tsang, Amanda; Khalida, Chamanara; D'Orazio, Brianna; Kost, Rhonda G; Leinberger-Jabari, Andrea; Coffran, Cameron; Evering, Teresa H; Coller, Barry S; Balachandra, Shirish; Urban, Tracie; Parola, Claude; Salvato, Scott; Jenks, Nancy; Wu, Daren; Burgess, Rhonda; Chung, Marilyn; de Lencastre, Herminia; Tomasz, Alexander

    2015-08-01

    In November 2011, The Rockefeller University Center for Clinical and Translational Science (CCTS), the Laboratory of Microbiology and Infectious Diseases, and Clinical Directors Network (CDN) launched a research and learning collaborative project with six community health centers in the New York City metropolitan area to determine the nature (clonal type) of community-acquired Staphylococcus aureus strains causing skin and soft tissue infections (SSTIs). Between November 2011 and March 2013, wound and nasal samples from 129 patients with active SSTIs suspicious for S. aureus were collected and characterized by molecular typing techniques. In 63 of 129 patients, the skin wounds were infected by S. aureus: methicillin-resistant S. aureus (MRSA) was recovered from 39 wounds and methicillin-sensitive S. aureus (MSSA) was recovered from 24. Most-46 of the 63-wound isolates belonged to the CC8/Panton-Valentine leukocidin-positive (PVL(+)) group of S. aureus clone USA300: 34 of these strains were MRSA and 12 were MSSA. Of the 63 patients with S. aureus infections, 30 were also colonized by S. aureus in the nares: 16 of the colonizing isolates were MRSA, and 14 were MSSA, and the majority of the colonizing isolates belonged to the USA300 clonal group. In most cases (70%), the colonizing isolate belonged to the same clonal type as the strain involved with the infection. In three of the patients, the identity of invasive and colonizing MRSA isolates was further documented by whole-genome sequencing.

  2. 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.

  3. Comparison of Methicillin Resistant Staphylococcus Aureus in Healthy Community Hospital Visitors [CA-MRSA] and Hospital Staff [HA-MRSA

    PubMed Central

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

    2015-01-01

    Background The prevalence of community-associated methicillin-resistant Staphylococcus aureus [CA-MRSA] is unknown in Oman. Methods Nasal and cell phones swabs were collected from hospital visitors and health-care workers on sterile polyester swabs and directly inoculated onto a mannitol salt agar containing oxacillin, allowing growth of methicillin-resistant microorganisms. Antibiotic susceptibility tests were performed using Kirby Bauer’s disc diffusion method on the isolates. Minimum inhibitory concentration (MIC) was determined for vancomycin and teicoplanin against the resistant isolates of MRSA by the Epsilometer [E] test. A brief survey questionnaire was requested be filled to ascertain the exposure to known risk factors for CA-MRSA carriage. Results Overall, nasal colonization with CA-MRSA was seen in 34 individuals (18%, 95% confidence interval [CI] =12.5%–23.5%), whereas, CA-MRSA was additionally isolated from the cell phone surface in 12 participants (6.3%, 95% CI =5.6%–6.98%). Nasal colonization prevalence with hospital-acquired [HA] MRSA was seen in 16 individuals (13.8%, 95% confidence interval [CI] =7.5%–20.06%), whereas, HA-MRSA was additionally isolated from the cell phone surface in 3 participants (2.6%, 95% CI =1.7–4.54). Antibiotic sensitivity was 100% to linezolid and rifampicin in the CA-MRSA isolates. Antibiotic resistance to vancomycin and clindamycin varied between 9–11 % in the CA-MRSA isolates. Mean MIC for vancomycin amongst CA- and HA-MRSA were 6.3 and 9.3 μg/ml, whereas for teicoplanin they were 13 and 14 μg/ml respectively by the E-test. There was no statistically significant correlation between CA-MRSA nasal carriage and the risk factors (P>0.05, Chi-square test). Conclusions The prevalence of CA-MRSA in the healthy community hospital visitors was 18 % (95% CI, 12.5% to 23.5%) as compared to 13.8% HA-MRSA in the hospital health-care staff. Despite a significant prevalence of CA-MRSA, these strains were mostly sensitive

  4. 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.

  5. Community-Associated Methicillin-Resistant Staphylococcus aureus Infections in the Athlete

    PubMed Central

    2009-01-01

    Context: Community-associated methicillin-resistant Staphlococcus aureus (CA-MRSA) has become of increasing concern in the athletic setting. Appropriate recognition, treatment, and prevention measures are all paramount to protect individual athletes and teamwide outbreaks. Evidence Acquisition: Relevant electronic databases (Medline or PubMed) through 2008 were searched. Articles and studies relevant to this topic were reviewed for pertinent clinical information. Study Type: Clinical review. Results: CA-MRSA is an increasing problem both in the community at large and in the athletic population. Conclusion: Early infections based on methicillin-resistant Staphlococcus aureus are often misidentified, leading to delay in appropriate treatment. A high level of suspicion, prompt recognition, and appropriate treatment can minimize morbidity associated with CA-MRSA. Careful selection of antibiotics in suspected cases is important, with more severe infections requiring hospitalization and intravenous antibiotics. Eradication of bacteria in colonized patients has not yet proven to be effective. Prevention of infections is multifaceted, and it includes education, proper personal hygiene, routine cleaning of equipment, and proper wound care. PMID:23015900

  6. 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

  7. 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

  8. 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.

  9. 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.

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

    PubMed

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

    2016-09-15

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

  11. Potential targets by pentacyclic triterpenoids from Callicarpa farinosa against methicillin-resistant and sensitive Staphylococcus aureus.

    PubMed

    Chung, Pooi Yin; Chung, Lip Yong; Navaratnam, Parasakthi

    2014-04-01

    The evolution of antibiotic resistance in Staphylococcus aureus showed that there is no long-lasting remedy against this pathogen. The limited number of antibacterial classes and the common occurrence of cross-resistance within and between classes reinforce the urgent need to discover new compounds targeting novel cellular functions not yet targeted by currently used drugs. One of the experimental approaches used to discover novel antibacterials and their in vitro targets is natural product screening. Three known pentacyclic triterpenoids were isolated for the first time from the bark of Callicarpa farinosa Roxb. (Verbenaceae) and identified as α-amyrin [3β-hydroxy-urs-12-en-3-ol], betulinic acid [3β-hydroxy-20(29)-lupaene-28-oic acid], and betulinaldehyde [3β-hydroxy-20(29)-lupen-28-al]. These compounds exhibited antimicrobial activities against reference and clinical strains of methicillin-resistant (MRSA) and methicillin-sensitive S. aureus (MSSA), with minimum inhibitory concentration (MIC) ranging from 2 to 512 μg/mL. From the genome-wide transcriptomic analysis to elucidate the antimicrobial effects of these compounds, multiple novel cellular targets in cell division, two-component system, ABC transporters, fatty acid biosynthesis, peptidoglycan biosynthesis, aminoacyl-tRNA synthetases, ribosomes and β-lactam resistance pathways are affected, resulting in destabilization of the bacterial cell membrane, halt in protein synthesis, and inhibition of cell growth that eventually lead to cell death. The novel targets in these essential pathways could be further explored in the development of therapeutic compounds for the treatment of S. aureus infections and help mitigate resistance development due to target alterations.

  12. High prevalence of methicillin resistant staphylococci strains isolated from surgical site infections in Kinshasa

    PubMed Central

    Iyamba, Jean-Marie Liesse; Wambale, José Mulwahali; Lukukula, Cyprien Mbundu; Takaisi-Kikuni, Ntondo za Balega

    2014-01-01

    Introduction Surgical site infections (SSIs) after surgery are usually caused by Staphylococcus aureus and coagulase-negative staphylococci (CNS). In low income countries, methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase-negative staphylococci (MR-CNS) surgical site infections are particularly associated with high treatment cost and remain a source of mortality and morbidity. This study aimed to determine the prevalence and the sensitivity to antibiotics of MRSA and MR-CNS isolated from SSIs. Methods Wound swabs were collected from 130 hospitalized surgical patients in two major hospitals of Kinshasa. S. aureus and CNS strains were identified by standard microbiological methods and latex agglutination test (Pastorex Staph-Plus). The antibiotic susceptibility of all staphylococcal strains was carried out using disk-diffusion method. Results Eighty nine staphylococcal strains were isolated. Out of 74 S. aureus and 15 CNS isolated, 47 (63.5%) and 9 (60%) were identified as MRSA and MR-CNS respectively. Among the MRSA strains, 47 strains (100%) were sensitive to imipenem, 39 strains (89%) to amoxycillin-clavulanic acid and 38 strains (81%) to vancomycin. All MR-CNS were sensitive to imipenem, amoxycillin-clavulanic acid and vancomycin. The isolated MRSA and MR-CNS strains showed multidrug resistance. They were both resistant to ampicillin, cotrimoxazole, erythromycin, clindamycin, ciprofloxacin, cefotaxime and ceftazidime. Conclusion The results of the present study showed a high prevalence of MRSA and MR-CNS. Imipenem, amoxycillin-clavulanic acid and vancomycin were the most active antibiotics. This study suggests that antibiotic surveillance policy should become national priority as MRSA and MR-CNS were found to be multidrug resistant. PMID:25478043

  13. SCC mec typing and antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) from pigs of Northeast India.

    PubMed

    Rajkhowa, S; Sarma, D K; Pegu, S R

    2016-12-01

    Staphylococcus aureus is one of the most important pathogens of both humans and animal. Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen that causes serious infections both in hospitals and communities due to its multidrug resistance tendency. This study was undertaken to characterize the MRSA isolates from pigs and to determine the antimicrobial resistance of these isolates. Forty nine MRSA strains (one strain per positive pig) isolated from pigs of Northeast India were characterized by SCCmec typing and antimicrobial resistance. The overall prevalence of MRSA was 7.02 % with the highest prevalence recorded in pigs aged 1-3 months (P = 0.001) and in nasal samples (P = 0.005). Two SCC mec types (type III and V) were found in Indian pigs with predominance of type V. All isolates were resistant to penicillin. Seventeen resistance groups were observed where 87.75 % isolates showed multidrug resistance (showed resistance to three or more classes of antimicrobials). The most predominant resistance pattern observed was Oxytetracycline + Penicillin + Sulfadiazine + Tetracycline accounting 12.24 % of the isolates. The present study contributes to the understanding of characteristics and antimicrobial resistance of porcine MRSA isolates which in turn will help in devising strategy for the control of this pathogen. Findings of the study also throw light on multidrug resistance MRSA and emphasize the need for judicious use of antimicrobials in animal practice.

  14. 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.

  15. 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.

  16. 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.

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  19. Antimicrobial Selection in the Face of Nasal Methicillin-Resistant Staphylococcus aureus-Polymerase Chain Recombination Testing in Thermal Injury Patients.

    PubMed

    Haith, Linwood R; Patton, Mary L; Guilday, Robert E; Stair-Buchmann, Megan E; Reigart, Cynthia L; Young, Christine; Ackerman, Bruce H

    2016-01-01

    Emergence of resistance to vancomycin and the increasing incidence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) warrant careful initiation of antimicrobial agents after nasal swab polymerase chain recombination (PCR) MRSA positive screen. Current MRSA PCR nasal swab (PCR) screening does not distinguish non-hospital-acquired strains. A retrospective, institutional review board-approved study of collected PCR screenings among 826 burn center admissions over a 23-month period assessed culture results, antimicrobial agents chosen, and patient demographics. Seventy-seven of the 826 were known chronic carriers (n = 11); had MRSA on initial PCR (n = 48); or converted to positive PCR screen on later testing (n = 18). The 48 patients with initial positive PCR were decolonized with mupirocin. MRSA carriers were not decolonized. The 18 patients who became PCR positive were also not decolonized with 10 having positive cultures. The 48 initial PCR nasal swab positive patients represented 5.8% of admissions. Demographic data did not differ among chronic carriers, initial PCR positive patients, nor those converting to PCR positive. Length of stay was shorter for initial PCR positive decolonized patients (P < .05) and they had a 35% of decrease in MRSA infection. All 11 chronic carriers became infected with MRSA; however, five had non-hospital-acquired MRSA and two solely non-hospital-acquired MRSA. For the 48 PCR positive patients, 17 had isolated MRSA and one having exclusively non-hospital-acquired MRSA. Of the 39 patients with isolated MRSA, 20 (43%) non-hospital-acquired MRSA. Non-hospital-acquired MRSA was 43%, however PCR fails to distinguish hospital-acquired MRSA from community-acquired MRSA.

  20. The role of mecA and blaZ regulatory elements in mecA expression by regional clones of methicillin-resistant Staphylococcus pseudintermedius.

    PubMed

    Black, C C; Eberlein, L C; Solyman, S M; Wilkes, R P; Hartmann, F A; Rohrbach, B W; Bemis, D A; Kania, S A

    2011-08-05

    Two major regional clones of methicillin-resistant Staphylococcus pseudintermedius (MRSP) have been identified in Europe and North America. They are designated multilocus sequence types (ST) 71 and 68 and contain staphylococcal chromosome cassette (SCCmec) types II-III and V(T), respectively. One notable difference between the two clones is a deletion in the mecI/mecR1 regulatory apparatus of ST 68 SCCmec V(T). This deletion in analogous methicillin-resistant Staphylococcus aureus (MRSA) results in more responsive and greater expression of the mecA encoded penicillin-binding protein 2a, and is associated with SCCmec types occurring in community-acquired MRSA lineages. The aim of this study was to characterize mec and bla regulatory apparatuses in MRSP and determine their effects on expression of mecA. Seventeen S. pseudintermedius isolates representing nine methicillin-resistant ST lineages were screened for the presence of the repressors blaI and mecI and sensors blaR1 and mecR1. The bla and mec operons for each isolate were sequenced and compared for homology between the repressor open-reading frames (ORF), sensor ORFs, and mecA promoter regions. A real-time reverse transcriptase PCR expression assay was developed, validated and applied to nine isolates determining the effect of oxacillin induction on mecA transcription. Significant differences were found in mecA expression between isolates with a full regulatory complement (mecI/mecR1 and blaI/blaR1) and those with truncated and/or absent regulatory elements. Isolates representative of European and North American MRSP ST regional clones have dissimilar mecA responses to oxacillin.

  1. Impact of Antibiotic Exposure Patterns on Selection of Community-Associated Methicillin-Resistant Staphylococcus aureus in Hospital Settings▿†

    PubMed Central

    Kardaś-Słoma, Lidia; Boëlle, Pierre Yves; Opatowski, Lulla; Brun-Buisson, Christian; Guillemot, Didier; Temime, Laura

    2011-01-01

    Community-associated methicillin-resistant S. aureus (CA-MRSA) is increasingly common in hospitals, with potentially serious consequences. The aim of this study was to assess the impact of antibiotic prescription patterns on the selection of CA-MRSA within hospitals, in a context of competition with other circulating staphylococcal strains, including methicillin-sensitive (MSSA) and hospital-associated methicillin-resistant (HA-MRSA) strains. We developed a computerized agent-based model of S. aureus transmission in a hospital ward in which CA-MRSA, MSSA, and HA-MRSA strains may cocirculate. We investigated a wide range of antibiotic prescription patterns in both intensive care units (ICUs) and general wards, and we studied how differences in antibiotic exposure may explain observed variations in the success of CA-MRSA invasion in the hospitals of several European countries and of the United States. Model predictions underlined the influence of antibiotic prescription patterns on CA-MRSA spread in hospitals, especially in the ICU, where the endemic prevalence of CA-MRSA carriage can range from 3% to 20%, depending on the simulated prescription pattern. Large antibiotic exposure with drugs effective against MSSA but not MRSA was found to promote invasion by CA-MRSA. We also found that, should CA-MRSA acquire fluoroquinolone resistance, a major increase in CA-MRSA prevalence could ensue in hospitals worldwide. Controlling the spread of highly community-prevalent CA-MRSA within hospitals is a challenge. This study demonstrates that antibiotic exposure strategies could participate in this control. This is all the more important in wards such as ICUs, which may play the role of incubators, promoting CA-MRSA selection in hospitals. PMID:21788461

  2. Targets for Combating the Evolution of Acquired Antibiotic Resistance.

    PubMed

    Culyba, Matthew J; Mo, Charlie Y; Kohli, Rahul M

    2015-06-16

    Bacteria possess a remarkable ability to rapidly adapt and evolve in response to antibiotics. Acquired antibiotic resistance can arise by multiple mechanisms but commonly involves altering the target site of the drug, enzymatically inactivating the drug, or preventing the drug from accessing its target. These mechanisms involve new genetic changes in the pathogen leading to heritable resistance. This recognition underscores the importance of understanding how such genetic changes can arise. Here, we review recent advances in our understanding of the processes that contribute to the evolution of antibiotic resistance, with a particular focus on hypermutation mediated by the SOS pathway and horizontal gene transfer. We explore the molecular mechanisms involved in acquired resistance and discuss their viability as potential targets. We propose that additional studies into these adaptive mechanisms not only can provide insights into evolution but also can offer a strategy for potentiating our current antibiotic arsenal.

  3. Targets for Combating the Evolution of Acquired Antibiotic Resistance

    PubMed Central

    2015-01-01

    Bacteria possess a remarkable ability to rapidly adapt and evolve in response to antibiotics. Acquired antibiotic resistance can arise by multiple mechanisms but commonly involves altering the target site of the drug, enzymatically inactivating the drug, or preventing the drug from accessing its target. These mechanisms involve new genetic changes in the pathogen leading to heritable resistance. This recognition underscores the importance of understanding how such genetic changes can arise. Here, we review recent advances in our understanding of the processes that contribute to the evolution of antibiotic resistance, with a particular focus on hypermutation mediated by the SOS pathway and horizontal gene transfer. We explore the molecular mechanisms involved in acquired resistance and discuss their viability as potential targets. We propose that additional studies into these adaptive mechanisms not only can provide insights into evolution but also can offer a strategy for potentiating our current antibiotic arsenal. PMID:26016604

  4. Trypanosoma congolense: Natural and Acquired Resistance in the Bovine

    DTIC Science & Technology

    1980-08-01

    of Immune or natural and acquired Immunity In cattle to partially Immune dams (Whiteside 1962). trypanosomiasis . It has been postulated Certain breeds...of cattle also appear to be that young animals are more resistant to naturally resistant to trypanosome infection trypanosomiasis than adults (Fiennes...1970), Murray el al. (1979). Attempts to induce immunity to trypanosomiasis under field I Reprint requests should be addressed to B. T, conditions

  5. β-Lactam Resistance in Methicillin-Resistant Staphylococcus aureus USA300 Is Increased by Inactivation of the ClpXP Protease

    PubMed Central

    Bæk, Kristoffer T.; Gründling, Angelika; Mogensen, René G.; Thøgersen, Louise; Petersen, Andreas; Paulander, Wilhelm

    2014-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) has acquired the mecA gene encoding a peptidoglycan transpeptidase, penicillin binding protein 2a (PBP2a), which has decreased affinity for β-lactams. Quickly spreading and highly virulent community-acquired (CA) MRSA strains recently emerged as a frequent cause of infection in individuals without exposure to the health care system. In this study, we found that the inactivation of the components of the ClpXP protease substantially increased the β-lactam resistance level of a CA-MRSA USA300 strain, suggesting that the proteolytic activity of ClpXP controls one or more pathways modulating β-lactam resistance. These pathways do not involve the control of mecA expression, as the cellular levels of PBP2a were unaltered in the clp mutants. An analysis of the cell envelope properties of the clpX and clpP mutants revealed a number of distinct phenotypes that may contribute to the enhanced β-lactam tolerance. Both mutants displayed significantly thicker cell walls, increased peptidoglycan cross-linking, and altered composition of monomeric muropeptide species compared to those of the wild types. Moreover, changes in Sle1-mediated peptidoglycan hydrolysis and altered processing of the major autolysin Atl were observed in the clp mutants. In conclusion, the results presented here point to an important role for the ClpXP protease in controlling cell wall metabolism and add novel insights into the molecular factors that determine strain-dependent β-lactam resistance. PMID:24867990

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

    PubMed

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

    2013-01-01

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

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

    PubMed

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

    2014-07-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  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. 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.

  11. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  13. 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.

  14. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    PubMed Central

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

    2015-01-01

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

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. Phenotypic and genotypic characteristics of methicillin/oxacillin-resistant Staphylococcus intermedius isolated from clinical specimens during routine veterinary microbiological examinations.

    PubMed

    Zubeir, I E M El; Kanbar, T; Alber, J; Lämmler, C; Akineden, O; Weiss, R; Zschöck, M

    2007-03-31

    Methicillin/oxacillin resistance of 10 S. intermedius strains was investigated by conventional and molecular methods. The strains tested had been isolated in Germany during routine veterinary microbiological examinations of specimens from a small animal clinic between May and September 2005. Epidemiological relationships of the strains were studied by macrorestriction analysis of their chromosomal DNA using pulsed field gel electrophoresis (PFGE). Species identity of the 10 S. intermedius strains was confirmed by conventional methods and by PCR mediated amplification of S. intermedius specific segments of thermonuclease encoding gene nuc. As controls, four methicillin/oxacillin resistant S. intermedius (MRSI) strains obtained from specimens sent by four veterinarians and three selected methicillin/oxacillin sensitive S. intermedius (MSSI), also obtained from the small animal clinic, were tested. The 10 strains, representing approximately 6% of all S. intermedius isolated from the clinic throughout the time period mentioned above, and the four MRSI obtained from veterinarians, were methicillin/oxacillin and penicillin resistant using disk diffusion tests and could be cultivated on oxacillin resistant screening agar base (ORSAB). Both resistances could be confirmed by multiplex PCR detecting the resistance genes mecA and blaZ. The three MSSI were methicillin/oxacillin sensitive in all tests. Epidemiological investigation by macrorestriction analysis of the chromosomal DNA of the strains by pulsed field gel electrophoresis revealed that all 10 MRSI strains obtained from the clinic and the four MRSI strains obtained from veterinarians, in contrast to the three MSSI strains, represent identical or closely related bacterial clones possibly indicating a cross-infection of the animals in the clinic and the distribution of a single MRSI clone in the pet population.

  2. 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

  3. 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.

  4. Methicillin-resistant Staphylococcus aureus carriage among veterinary staff and dogs in private veterinary clinics in Hokkaido, Japan.

    PubMed

    Ishihara, Kanako; Saito, Mieko; Shimokubo, Natsumi; Muramatsu, Yasukazu; Maetani, Shigeki; Tamura, Yutaka

    2014-03-01

    To explore the prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) in veterinary medical practices, MRSA carriage was tested among 96 veterinarians (Vets), 70 veterinary technicians (VTs) and 292 dogs with which they had contact at 71 private veterinary clinics (VCs) in Hokkaido, Japan. MRSA isolates were obtained from 22 Vets [22.9%] and 7 VTs [10%]. The prevalence of MRSA among Vets was as high as that found in an academic veterinary hospital in our previous study. In contrast, only two blood donor dogs and one dog with liver disease (1.0%, 3/292) yielded MRSA. All MRSA-positive dogs were reared or treated in different VCs, in each of which at least one veterinary staff member carrying MRSA worked. Sequence types (ST) identified by multilocus sequence typing, spa types, and SCCmec types for canine MRSA isolates (ST5-spa t002-SCCmec II [from two dogs] or ST30-spa t021-SCCmec IV [from a dog]) were concordant with those from veterinary staff members in the same clinics as the MRSA-positive dogs, with which they had potentially had contact. Most MRSA isolates from veterinary staff were the same genotype (SCCmec type II and spa type t002) as a major hospital-acquired MRSA clone in Japan. The remaining MRSA was the same genotypes as domestic and foreign community-associated MRSA. Measures against MRSA infection should be provided in private VCs.

  5. Effects of microgravity on the virulence of Listeria monocytogenes, Enterococcus faecalis, Candida albicans, and methicillin-resistant Staphylococcus aureus.

    PubMed

    Hammond, Timothy G; Stodieck, Louis; Birdsall, Holly H; Becker, Jeanne L; Koenig, Paul; Hammond, Jeffrey S; Gunter, Margaret A; Allen, Patricia L

    2013-11-01

    To evaluate effects of microgravity on virulence, we studied the ability of four common clinical pathogens--Listeria monocytogenes, methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, and Candida albicans--to kill wild type Caenorhabditis elegans (C. elegans) nematodes at the larval and adult stages. Simultaneous studies were performed utilizing spaceflight, clinorotation in a 2-D clinorotation device, and static ground controls. The feeding rate of worms for killed E. coli was unaffected by spaceflight or clinorotation. Nematodes, microbes, and growth media were separated until exposed to true or modeled microgravity, then mixed and grown for 48 h. Experiments were terminated by paraformaldehyde fixation, and optical density measurements were used to assay residual microorganisms. Spaceflight was associated with reduced virulence for Listeria, Enterococcus, MRSA, and Candida for both larval and adult C. elegans. These are the first data acquired with a direct in vivo assay system in space to demonstrate virulence. Clinorotation reproduced the effects of spaceflight in some, but not all, virulence assays: Candida and Enterococcus were less virulent for larval worms but not adult worms, whereas virulence of MRSA and Listeria were unaffected by clinorotation in tests with both adult and larval worms. We conclude that four common clinical microorganisms are all less virulent in space.

  6. Significant antibacterial activity and synergistic effects of camel lactoferrin with antibiotics against methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Redwan, Elrashdy M; El-Baky, Nawal Abd; Al-Hejin, Ahmed M; Baeshen, Mohammed N; Almehdar, Hussein A; Elsaway, Abdulrahman; Gomaa, Abu-Bakr M; Al-Masaudi, Saad Berki; Al-Fassi, Fahad A; AbuZeid, Isam Eldin; Uversky, Vladimir N

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) causes major healthcare problems in many countries, as it is present as several hospital- and community-associated strains. Hospital-associated MRSA is one of the most prevalent nosocomial pathogens throughout the world and infections caused by community-acquired MRSA are rising. This emphasizes the need for new and efficient anti-MRSA agents. We evaluated the antibacterial effects of camel lactoferrin (cLf) and human lactoferrin (hLf) alone and in combination with several antibiotics against MRSA. Antimicrobials were tested against MRSA and an S. aureus control strain by the agar disc diffusion method. The minimum inhibitory concentration (MIC) was determined for antimicrobials by the broth microdilution method. Synergy between cLf or hLf and antibiotics was examined by checkerboard and time-kill assays. The agar disc diffusion assay showed that MRSA growth was inhibited by cLf at 0.25-3 mg/ml and hLf at 1-3 mg/ml. cLf demonstrated 3 times higher inhibitory activity against MRSA than hLf in terms of MIC values (250 vs. 750 μg/ml, respectively). Biotinylated cLf was recognized by two membrane proteins of MRSA, 66-67 KDa. Combinations of cLf or hLf and oxacillin or vancomycin at sub-MIC levels enhanced in vitro antibacterial activity against MRSA compared with each agent alone.

  7. Phenotypic and genotypic correlates of daptomycin-resistant methicillin-susceptible Staphylococcus aureus clinical isolates.

    PubMed

    Kang, Kyoung-Mi; Mishra, Nagendra N; Park, Kun Taek; Lee, Gi-Yong; Park, Yong Ho; Bayer, Arnold S; Yang, Soo-Jin

    2017-02-01

    Daptomycin (DAP) has potent activity in vitro and in vivo against both methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains. DAP-resistance (DAP-R) in S. aureus has been mainly observed in MRSA strains, and has been linked to single nucleotide polymorphisms (SNPs) within the mprF gene leading to altered cell membrane (CM) phospholipid (PL) profiles, enhanced positive surface charge, and changes in CM fluidity. The current study was designed to delineate whether these same genotypic and phenotypic perturbations are demonstrated in clinically-derived DAP-R MSSA strains. We used three isogenic DAP-susceptible (DAP-S)/DAP-R strainpairs and compared: (i) presence of mprF SNPs, (ii) temporal expression profiles of the two key determinants (mprF and dltABCD) of net positive surface charge, (iii) increased production of mprF-dependent lysinylated-phosphatidylglycerol (L-PG), (iv) positive surface charge assays, and (v) susceptibility to cationic host defense peptides (HDPs) of neutrophil and platelet origins. Similar to prior data in MRSA, DAP-R (vs DAP-S) MSSA strains exhibited hallmark hot-spot SNPs in mprF, enhanced and dysregulated expression of both mprF and dltA, L-PG overproduction, HDP resistance and enhanced positive surface charge profiles. However, in contrast to most DAP-R MRSA strains, there were no changes in CM fluidity seen. Thus, charge repulsion via mprF-and dlt-mediated enhancement of positive surface charge may be the main mechanism to explain DAP-R in MSSA strains.

  8. Bullous impetigo in children infected with methicillin-resistant Staphylococcus aureus alone or in combination with methicillin-susceptible S. aureus: analysis of genetic characteristics, including assessment of exfoliative toxin gene carriage.

    PubMed

    Shi, Da; Higuchi, Wataru; Takano, Tomomi; Saito, Kohei; Ozaki, Kyoko; Takano, Misao; Nitahara, Yoshiyuki; Yamamoto, Tatsuo

    2011-05-01

    Among bullous impetigo isolates, exfoliative toxin (ET) gene carriage was found in 61.5% of methicillin-resistant Staphylococcus aureus (MRSA) isolates versus 90.6% of methicillin-susceptible S. aureus (MSSA) isolates. MRSA-only cases were ETB or ETA positive, while MRSA/MSSA coinfection cases were ET negative for MRSA but ETA positive for MSSA. Collagen adhesin may facilitate some MRSA infections.

  9. The action of NIR (808nm) laser radiation and gold nanorods labeled with IgA and IgG human antibodies on methicillin-resistant and methicillin sensitive strains of Staphylococcus aureus

    NASA Astrophysics Data System (ADS)

    Tuchina, Elena S.; Petrov, Pavel O.; Ratto, Fulvio; Centi, Sonia; Pini, Roberto; Tuchin, Valery V.

    2015-03-01

    The effect of NIR laser radiation (808 nm) on methicillin-sensitive and methicillin resistant strains of Staphylococcus aureus incubated with gold nanorods is studied. Nanorods having length of 44 (± 4) nm and diameter of 10 (± 3) nm with the absorption maximum in the NIR (800 nm), functionalized with human immunoglobulins IgA and IgG, were synthesized and used in the studies. The killing ability up to 97% of the microorganism populations by using this nanotechnology was shown.

  10. PBP2a Mutations Causing High-Level Ceftaroline Resistance in Clinical Methicillin-Resistant Staphylococcus aureus Isolates

    PubMed Central

    Long, S. Wesley; Olsen, Randall J.; Mehta, Shrenik C.; Palzkill, Timothy; Cernoch, Patricia L.; Perez, Katherine K.; Musick, William L.; Rosato, Adriana E.

    2014-01-01

    Ceftaroline is the first member of a novel class of cephalosporins approved for use in the United States. Although prior studies have identified eight ceftaroline-resistant methicillin-resistant Staphylococcus aureus (MRSA) isolates in Europe and Asia with MICs ranging from 4 to 8 mg/liter, high-level resistance to ceftaroline (>32 mg/liter) has not been described in MRSA strains isolated in the United States. We isolated a ceftaroline-resistant (MIC > 32 mg/liter) MRSA strain from the blood of a cystic fibrosis patient and five MRSA strains from the respiratory tract of this patient. Whole-genome sequencing identified two amino acid-altering mutations uniquely present in the ceftaroline-binding pocket of the transpeptidase region of penicillin-binding protein 2a (PBP2a) in ceftaroline-resistant isolates. Biochemical analyses and the study of isogenic mutant strains confirmed that these changes caused ceftaroline resistance. Thus, we identified the molecular mechanism of ceftaroline resistance in the first MRSA strain with high-level ceftaroline resistance isolated in the United States. PMID:25155594

  11. Diversity of antimicrobial resistance and virulence genes in methicillin-resistant non-Staphylococcus aureus staphylococci from veal calves.

    PubMed

    Argudín, M Angeles; Vanderhaeghen, Wannes; Butaye, Patrick

    2015-04-01

    In this study we determined whether methicillin-resistant non-Staphylococcus aureus (MRNAS) from veal calves may be a potential reservoir of antimicrobial-resistance and virulence genes. Fifty-eight MRNAS were studied by means of DNA-microarray and PCR for detection of antimicrobial resistance and virulence genes. The isolates carried a variety of antimicrobial-resistance genes [aacA-aphD, aadD, aph3, aadE, sat, spc, ampA, erm(A), erm(B), erm(C), erm(F), erm(T), lnu(A), msr(A)-msr(B), vga(A), mph(C), tet(K), tet(M), tet(L), cat, fexA, dfrA, dfrD, dfrG, dfrK, cfr, fusB, fosB, qacA, qacC, merA-merB]. Some isolates carried resistance genes without showing the corresponding resistance phenotype. Most MRNAS carried typical S. aureus virulence factors like proteases (sspP) and enterotoxins (seg) genes. Most Staphylococcus epidermidis isolates carried the arginine catabolic element, and nearly 40% of the Staphylococcus sciuri isolates carried leukocidins, and/or fibronectin-binding protein genes. MRNAS were highly multi-resistant and represent an important reservoir of antimicrobial resistance and virulence genes.

  12. 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.

  13. Mutations in mmpL and in the cell wall stress stimulon contribute to resistance to oxadiazole antibiotics in methicillin-resistant Staphylococcus aureus.

    PubMed

    Xiao, Qiaobin; Vakulenko, Sergei; Chang, Mayland; Mobashery, Shahriar

    2014-10-01

    Staphylococcus aureus is a leading cause of hospital- and community-acquired infections, which exhibit broad resistance to various antibiotics. We recently disclosed the discovery of the oxadiazole class of antibiotics, which has in vitro and in vivo activities against methicillin-resistant S. aureus (MRSA). We report herein that MmpL, a putative member of the resistance, nodulation, and cell division (RND) family of proteins, contributes to oxadiazole resistance in the S. aureus strain COL. Through serial passages, we generated two S. aureus COL variants that showed diminished susceptibilities to an oxadiazole antibiotic. The MICs for the oxadiazole against one strain (designated S. aureus COL(I)) increased reproducibly 2-fold (to 4 μg/ml), while against the other strain (S. aureus COL(R)), they increased >4-fold (to >8 μg/ml, the limit of solubility). The COL(R) strain was derived from the COL(I) strain. Whole-genome sequencing revealed 31 mutations in S. aureus COL(R), of which 29 were shared with COL(I). Consistent with our previous finding that oxadiazole antibiotics inhibit cell wall biosynthesis, we found 13 mutations that occurred either in structural genes or in promoters of the genes of the cell wall stress stimulon. Two unique mutations in S. aureus COL(R) were substitutions in two genes that encode the putative thioredoxin (SACOL1794) and MmpL (SACOL2566). A role for mmpL in resistance to oxadiazoles was discerned from gene deletion and complementation experiments. To our knowledge, this is the first report that a cell wall-acting antibiotic selects for mutations in the cell wall stress stimulon and the first to implicate MmpL in resistance to antibiotics in S. aureus.

  14. An in vitro analysis of the effects of various topical antimicrobial agents on methicillin-resistant and methicillin-sensitive strains of Staphylococcus aureus.

    PubMed

    Kaiser, Michael; Gil, Joel; Treu, Ryan; Valdes, Jose; Davis, Stephen

    2014-04-01

    Infections of acute and chronic wounds have a substantial negative impact on patient outcomes. Because bacterial resistance to traditional antimicrobials continues to increase, an in vitro study was conducted to examine current sensitivities of various methicillin-resistant and methicillin-sensitive strains of Staphylococcus aureus (MRSA and MSSA) to commonly used topical antimicrobial agents. Using fresh cultures of eight strains of MRSA and MSSA, the area of the zone of inhibition produced by various topical antimicrobials, including an aminoglycoside antibiotic, monocarboxylic acid antibiotic, pleuromutilin antibiotic, triple antibiotic ointment, and petrolatum ointment, was examined. Six culture plates per antimicrobial were prepared using the Kirby Bauer method; soy blood culture plates were inoculated with the bacteria, incubated for 24 hours at 37˚ C, and their zones of inhibition measured and calculated. Data were analyzed using ANOVA testing. Mupirocin treatment was the most effective antimicrobial, with areas of inhibition ranging from 30.34 cm2 to 61.70 cm2 (P <0.05), as compared to the next most effective, retapamulin, with areas of inhibition ranging from 11.97 cm2 to 23.54 cm2. This study provides current scientific data to help the development of a thoughtful rationale for the use of topical antimicrobials in wounds. Additional in vivo studies to substantiate these findings are needed.

  15. Characterization of canine and feline methicillin-resistant Staphylococcus pseudintermedius (MRSP) from Thailand.

    PubMed

    Kadlec, Kristina; Weiß, Sonja; Wendlandt, Sarah; Schwarz, Stefan; Tonpitak, Walaiporn

    2016-10-15

    Methicillin-resistant Staphylococcus pseudintermedius (MRSP) in small animal practice are very difficult to treat due to multi-resistance. In contrast to other countries, little is known about MRSP from Thailand. In particular, information on feline MRSP isolates in general is rare. In total, 39 MRSP isolates from dogs (n=28) and cats (n=11) from Thailand collected from independent clinical cases were used. Oxacillin resistance and presence of the mecA gene was confirmed. Susceptibility to additional 29 antimicrobial agents was tested according to CLSI recommendations. Antimicrobial resistance genes were detected by PCR assays. Molecular typing comprised spa typing, dru typing and macrorestriction analysis with subsequent pulsed-field gel electrophoresis (PFGE). For selected isolates, multi-locus sequence typing (MLST) was performed. All isolates were multi-resistant with resistance to at least six classes of antimicrobial agents. In all cases corresponding resistance genes were detected. In addition to mecA, the genes blaZ, catpC221, aacA/aphD, erm(B), dfrG, tet(M) and tet(K) were identified. Six spa types (t02, t05, t09, t10, t23, t72), eleven dru types (dt8ak, dt10ao, dt10cp, dt10cq, dt11a, dt11bo, dt11cb, dt11cj, dt11v, dt11y, dt11z) and 27 PFGE types (designated as A1-A10, B1-B8, C1-C2, D, E, F, G, H, I, J) were identified. MLST for one isolate of each main PFGE pattern A-J revealed seven types [ST45 (n=3), ST112, ST155, ST282 and the novel types ST432, ST433 (n=2) and ST434]. This study showed that MRSP isolates from clinical cases in individual dogs and cats in Thailand are multi-resistant with similar resistance genes and characteristics as isolates from Europe and North America.

  16. Emergence of methicillin-resistant Staphylococcus pseudintermedius in Switzerland: three cases of urinary tract infections in cats.

    PubMed

    Wettstein, K; Descloux, S; Rossano, A; Perreten, V

    2008-07-01

    Methicillin resistance has emerged in clinical isolates of Staphylococcus pseudintermedius from cats in Switzerland. Three cats suffering from urinary tract infections were infected with methicillin-resistant S. pseudintermedius (MRSP). Phenotypic and genotypic characterization of the resistance profile showed that the isolates displayed resistance to all beta-lactams and cephalosporins (blaZ, mecA), fluoroquinolones, tetracyclines [tet(K)], macrolides, lincosamides and streprogramins B [erm(B)], chloramphenicol (catpC221), trimethoprim [dfr(G)] and the aminoglycosides gentamicin [aac(6')-Ie-aph(2')-Ia], kanamycin and neomycin [aph(3')-III] and streptomycin [ant(6)-Ia]. They also harbor the leukocidin gene lukS-I. MRSP represents a new challenge for antibiotic therapy and this zoonotic bacteria may rapidly spread to animals and humans.

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. Surface plasmon resonance detection of E. coli and methicillin-resistant S. aureus using bacteriophages.

    PubMed

    Tawil, Nancy; Sacher, Edward; Mandeville, Rosemonde; Meunier, Michel

    2012-01-01

    Early diagnosis and appropriate treatment of Escherichia coli (E. coli) O157:H7 and methicillin-resistant Staphylococcus aureus (MRSA) are key elements in preventing resultant life-threatening illnesses, such as hemorrhagic colitis, hemolytic uremic syndrome, and septicemia. In this report, we describe the use of surface plasmon resonance (SPR) for the biodetection of pathogenic bacteria, using bacteriophages as the recognition elements. T4 bacteriophages were used to detect E. coli, while a novel, highly specific phage was used to detect MRSA. We found that the system permits label-free, real-time, specific, rapid and cost-effective detection of pathogens, for concentrations of 10(3) colony forming units/milliliter, in less than 20 min. This system promises to become a diagnostic tool for bacteria that cause major public concern for food safety, bioterrorism, and nosocomial infections.

  2. 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

  3. 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

  4. 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.

  5. 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

  6. Distribution of genes encoding aminoglycoside-modifying enzymes among clinical isolates of methicillin-resistant staphylococci.

    PubMed

    Perumal, N; Murugesan, S; Krishnan, P

    2016-01-01

    The objective of this study was to determine the distribution of genes encoding aminoglycoside-modifying enzymes (AMEs) and staphylococcal cassette chromosome mec (SCCmec) elements among clinical isolates of methicillin-resistant staphylococci (MRS). Antibiotic susceptibility test was done using Kirby-Bauer disk diffusion method. The presence of SCCmec types and AME genes, namely, aac (6')-Ie-aph (2''), aph (3')-IIIa and ant (4')-Ia was determined using two different multiplex polymerase chain reaction. The most encountered AME genes were aac (6')-Ie-aph (2'') (55.4%) followed by aph (3')-IIIa (32.3%) and ant (4')-Ia gene (9%). SCCmec type I (34%) was predominant in this study. In conclusion, the aac (6')-Ie-aph (2'') was the most common AME gene and SCCmec type I was most predominant among the MRS isolates.

  7. [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.

  8. In vitro and in vivo efficacy of the combination trimethoprim-sulfamethoxazole against clinical isolates of methicillin-resistant Staphylococcus aureus.

    PubMed Central

    Elwell, L P; Wilson, H R; Knick, V B; Keith, B R

    1986-01-01

    The in vitro susceptibilities of 16 independent, geographically distinct clinical isolates of methicillin-resistant Staphylococcus aureus to trimethoprim (TMP) in combination with sulfamethoxazole (SMX) were evaluated. Although methicillin-resistant S. aureus strains appear to be universally resistant to SMX, the combination TMP-SMX was found to be synergistic in vitro (in combination, the MICs of both drugs decreased 6- to 25-fold) as well as in vivo (5- to 6-fold reduction in TMP at 50% effective doses). PMID:3488022

  9. SpoVG Regulates Cell Wall Metabolism and Oxacillin Resistance in Methicillin-Resistant Staphylococcus aureus Strain N315

    PubMed Central

    Liu, Xiaoyu; Zhang, Shijie

    2016-01-01

    Increasing cases of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains in healthy individuals have raised concerns worldwide. MRSA strains are resistant to almost the entire family of β-lactam antibiotics due to the acquisition of an extra penicillin-binding protein, PBP2a. Studies have shown that spoVG is involved in oxacillin resistance, while the regulatory mechanism remains elusive. In this study, we have found that SpoVG plays a positive role in oxacillin resistance through promoting cell wall synthesis and inhibiting cell wall degradation in MRSA strain N315. Deletion of spoVG in strain N315 led to a significant decrease in oxacillin resistance and a dramatic increase in Triton X-100-induced autolytic activity simultaneously. Real-time quantitative reverse transcription-PCR revealed that the expression of 8 genes related to cell wall metabolism or oxacillin resistance was altered in the spoVG mutant. Electrophoretic mobility shift assay indicated that SpoVG can directly bind to the putative promoter regions of lytN (murein hydrolase), femA, and lytSR (the two-component system). These findings suggest a molecular mechanism in which SpoVG modulates oxacillin resistance by regulating cell wall metabolism in MRSA. PMID:27001809

  10. 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

  11. Enhanced adherence of methicillin-resistant Staphylococcus pseudintermedius sequence type 71 to canine and human corneocytes.

    PubMed

    Latronico, Francesca; Moodley, Arshnee; Nielsen, Søren Saxmose; Guardabassi, Luca

    2014-06-24

    The recent worldwide spread of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in dogs is a reason for concern due to the typical multidrug resistance patterns displayed by some MRSP lineages such as sequence type (ST) 71. The objective of this study was to compare the in vitro adherence properties between MRSP and methicillin-susceptible (MSSP) strains. Four MRSP, including a human and a canine strain belonging to ST71 and two canine non-ST71 strains, and three genetically unrelated MSSP were tested on corneocytes collected from five dogs and six humans. All strains were fully characterized with respect to genetic background and cell wall-anchored protein (CWAP) gene content. Seventy-seven strain-corneocyte combinations were tested using both exponential- and stationary-phase cultures. Negative binomial regression analysis of counts of bacterial cells adhering to corneocytes revealed that adherence was significantly influenced by host and strain genotype regardless of bacterial growth phase. The two MRSP ST71 strains showed greater adherence than MRSP non-ST71 (p < 0.0001) and MSSP (p < 0.0001). This phenotypic trait was not associated to any specific CWAP gene. In general, S. pseudintermedius adherence to canine corneocytes was significantly higher compared to human corneocytes (p < 0.0001), but the MRSP ST71 strain of human origin adhered equally well to canine and human corneocytes, suggesting that MRSP ST71 may be able to adapt to human skin. The genetic basis of the enhanced in vitro adherence of ST71 needs to be elucidated as this phenotypic trait may be associated to the epidemiological success and zoonotic potential of this epidemic MRSP clone.

  12. 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.

  13. Acquired resistance to gemcitabine and cross-resistance in human pancreatic cancer clones.

    PubMed

    Yoneyama, Hiroshi; Takizawa-Hashimoto, Asako; Takeuchi, Osamu; Watanabe, Yukiko; Atsuda, Koichiro; Asanuma, Fumiki; Yamada, Yoshinori; Suzuki, Yukio

    2015-01-01

    The efficacy of gemcitabine (GEM), a standard treatment agent for pancreatic cancer, is insufficient because of primary or acquired resistance to this drug. Patients with tumors intrinsically sensitive to GEM gradually acquire resistance and require a shift to second agents, which are associated with the risk of cross-resistance. However, whether cross-resistance is actually present has long been disputed. Using six GEM-resistant and four highly GEM-resistant clones derived from the pancreatic cancer cell line BxPC-3, we determined the resistance of each clone and parent cell line to GEM and four anticancer agents (5-FU, CDDP, CPT-11, and DTX). The GEM-resistant clones had different resistances to GEM and other agents, and did not develop a specific pattern of cross-resistance. This result shows that tumor cells are heterogeneous. However, all highly GEM-resistant clones presented overexpression of ribonucleotide reductase subunit M1 (RRM1), a target enzyme for metabolized GEM, and showed cross-resistance with 5-FU. The expression level of RRM1 was high; therefore, resistance to GEM was high. We showed that a tumor cell acquired resistance to GEM, and cross-resistance developed in one clone. These results suggest that only cells with certain mechanisms for high-level resistance to GEM survive against selective pressure applied by highly concentrated GEM. RRM1 may be one of the few factors that can induce high resistance to GEM and a suitable therapeutic target for GEM-resistant pancreatic cancer.

  14. A persistent antimicrobial resistance pattern and limited methicillin-resistance-associated genotype in a short-term Staphylococcus aureus carriage isolated from a student population.

    PubMed

    Mat Azis, Norhidayah; Pung, Hui P; Abdul Rachman, Abdul R; Amin Nordin, Syafinaz; Sarchio, Seri N E; Suhaili, Zarizal; Mohd Desa, Mohd N

    The aim of the present study was to assess and compare the antimicrobial susceptibility pattern against a panel of antibiotics and molecular and methicillin resistance-associated genotypes of 120 carriage S. aureus isolates previously isolated from a student population at two isolation events within a one-month interval. The antibiotic susceptibility of isolates was determined using the Kirby-Bauer disc-diffusion method (cefoxitin by Etest). The MRSA was screened using polymerase chain reaction for the presence of the mecA gene. The mecA-positive isolates were subjected to staphylococcal cassette chromosome (SCC) mec typing, multilocus sequence typing (MLST) and eBURST analysis. All isolates were characterized for the presence of the Panton-Valentine leukocidin (PVL) gene, an enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) pattern and the spa type. For the two occasions where S. aureus was isolated, the highest frequency of resistance was observed for penicillin (70% and 65%, respectively), with a lower rate against erythromycin and tetracycline (<12%). All isolates were susceptible to ciprofloxacin and gentamycin. As for methicillin resistance, eight isolates had minimum inhibitory concentrations (MIC) of resistant categories, but 10 isolates (8.33%) were positive for the mecA gene. The mecA-positive isolates belonged to SCCmec types I (n=9) and V (n=1). MLST was resolved for only three MRSAs, ST508 (n=1), ST88 (n=1) and ST96 (n=1). The results of the eBURST analysis showed that the MRSA isolates analyzed in the present study were potentially related to MRSA identified in other countries. Approximately half of the persistent S. aureus carriers harbored S. aureus of a similar spa type in the respective individuals during both isolation events. A persistent antimicrobial pattern and limited distinct MRSAs were observed over the short study period. The latter frequently exhibited SCCmec type I, commonly associated with hospital-acquired

  15. 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

  16. 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.

  17. Diaryltriazenes as antibacterial agents against methicillin resistant Staphylococcus aureus (MRSA) and Mycobacterium smegmatis.

    PubMed

    Vajs, Jure; Proud, Conor; Brozovic, Anamaria; Gazvoda, Martin; Lloyd, Adrian; Roper, David I; Osmak, Maja; Košmrlj, Janez; Dowson, Christopher G

    2017-02-15

    Diaryltriazene derivatives were synthesized and evaluated for their antimicrobial properties. Initial experiments showed some of these compounds to have activity against both methicillin-resistant strains of Staphylococus aureus (MRSA) and Mycobacterium smegmatis, with MICs of 0.02 and 0.03 μg/mL respectively. Those compounds with potent anti-staphylococcal and anti-mycobacterial activity were not found to act as growth inhibitors of mammalian cell lines or yeast. Furthermore, we demonstrated that one of the most active anti-MRSA diaryltriazene derivatives was subject to very low frequencies of resistance at <10(-9). Whole genome sequencing of resistant isolates identified mutations in the enzyme that lysylates phospholipids. This could result in the modification of phospholipid metabolism and consequently the characteristics of the staphylococcal cell membrane, ultimately modifying the sensitivity of these pathogens to triazene challenge. Our work has therefore extended the potential range of triazenes, which could yield novel antimicrobials with low levels of resistance.

  18. Crystal Structures of Wild-type and Mutant Methicillin-resistant Staphylococcus aureus Dihydrofolate Reductase Reveal an Alternative Conformation of NADPH that may be Linked to Trimethoprim Resistance

    SciTech Connect

    Frey, K.; Liu, J; Lombardo, M; Bolstad, D; Wright, D; Anderson, A

    2009-01-01

    Both hospital- and community-acquired Staphylococcus aureus infections have become major health concerns in terms of morbidity, suffering and cost. Trimethoprim-sulfamethoxazole (TMP-SMZ) is an alternative treatment for methicillin-resistant S. aureus (MRSA) infections. However, TMP-resistant strains have arisen with point mutations in dihydrofolate reductase (DHFR), the target for TMP. A single point mutation, F98Y, has been shown biochemically to confer the majority of this resistance to TMP. Using a structure-based approach, we have designed a series of novel propargyl-linked DHFR inhibitors that are active against several trimethoprim-resistant enzymes. We screened this series against wild-type and mutant (F98Y) S. aureus DHFR and found that several are active against both enzymes and specifically that the meta-biphenyl class of these inhibitors is the most potent. In order to understand the structural basis of this potency, we determined eight high-resolution crystal structures: four each of the wild-type and mutant DHFR enzymes bound to various propargyl-linked DHFR inhibitors. In addition to explaining the structure-activity relationships, several of the structures reveal a novel conformation for the cofactor, NADPH. In this new conformation that is predominantly associated with the mutant enzyme, the nicotinamide ring is displaced from its conserved location and three water molecules complete a network of hydrogen bonds between the nicotinamide ring and the protein. In this new position, NADPH has reduced interactions with the inhibitor. An equilibrium between the two conformations of NADPH, implied by their occupancies in the eight crystal structures, is influenced both by the ligand and the F98Y mutation. The mutation induced equilibrium between two NADPH-binding conformations may contribute to decrease TMP binding and thus may be responsible for TMP resistance.

  19. Antimicrobial activity of zinc and titanium dioxide nanoparticles against biofilm-producing methicillin-resistant Staphylococcus aureus

    NASA Astrophysics Data System (ADS)

    Jesline, A.; John, Neetu P.; Narayanan, P. M.; Vani, C.; Murugan, Sevanan

    2015-02-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major nosocomial pathogens responsible for a wide spectrum of infections and the emergence of bacterial resistance to antibiotics has lead to treatment drawbacks towards large number of drugs. Formation of biofilms is the main contributing factor to antibiotic resistance. The development of reliable processes for the synthesis of zinc oxide nanoparticles is an important aspect of nanotechnology today. Zinc oxide and titanium dioxide nanoparticles comprise well-known inhibitory and bactericidal effects. Emergence of antimicrobial resistance by pathogenic bacteria is a major health problem in recent years. This study was designed to determine the efficacy of zinc and titanium dioxide nanoparticles against biofilm producing methicillin-resistant S. aureus. Biofilm production was detected by tissue culture plate method. Out of 30 MRSA isolates, 22 isolates showed strong biofilm production and 2 showed weak and moderate biofilm formation. Two strong and weak biofilm-producing methicillin-resistant S. aureus isolates were subjected to antimicrobial activity using commercially available zinc and titanium dioxide nanoparticles. Thus, the nanoparticles showed considerably good activity against the isolates, and it can be concluded that they may act as promising, antibacterial agents in the coming years.

  20. Changes in the Population of Methicillin-Resistant Staphylococcus pseudintermedius and Dissemination of Antimicrobial-Resistant Phenotypes in the Netherlands

    PubMed Central

    Verstappen, Koen M.; Broens, Els M.; Laarhoven, Laura M.; van Duijkeren, Engeline; Hordijk, Joost; de Heus, Phebe; Spaninks, Mirlin; Timmerman, Arjen J.; Wagenaar, Jaap A.

    2015-01-01

    Methicillin-resistant Staphylococcus pseudintermedius (MRSP), which is often multidrug resistant (MDR), has recently emerged as a threat to canine health worldwide. Knowledge of the temporal distribution of specific MRSP lineages, their antimicrobial resistance phenotypes, and their association with clinical conditions may help us to understand the emergence and spread of MRSP in dogs. The aim of this study was to determine the yearly proportions of MRSP lineages and their antimicrobial-resistant phenotypes in the Netherlands and to examine possible associations with clinical conditions. MRSP was first isolated from a canine specimen submitted for diagnostics to the Faculty of Veterinary Medicine of Utrecht University in 2004. The annual cumulative incidence of MRSP among S. pseudintermedius increased from 0.9% in 2004 to 7% in 2013. MRSP was significantly associated with pyoderma and, to a lesser extent, with wound infections and otitis externa. Multilocus sequence typing (MLST) of 478 MRSP isolates yielded 39 sequence types (ST) belonging to 4 clonal complexes (CC) and 15 singletons. CC71 was the dominant lineage that emerged since 2004, and CC258, CC45, and several unlinked isolates became more frequent during the following years. All but two strains conferred an MDR phenotype, but strains belonging to CC258 or singletons were less resistant. In conclusion, our study showed that MDR CC71 emerged as the dominant lineage from 2004 and onward and that less-resistant lineages were partly replacing CC71. PMID:26582835

  1. Changes in the Population of Methicillin-Resistant Staphylococcus pseudintermedius and Dissemination of Antimicrobial-Resistant Phenotypes in the Netherlands.

    PubMed

    Duim, Birgitta; Verstappen, Koen M; Broens, Els M; Laarhoven, Laura M; van Duijkeren, Engeline; Hordijk, Joost; de Heus, Phebe; Spaninks, Mirlin; Timmerman, Arjen J; Wagenaar, Jaap A

    2016-02-01

    Methicillin-resistant Staphylococcus pseudintermedius (MRSP), which is often multidrug resistant (MDR), has recently emerged as a threat to canine health worldwide. Knowledge of the temporal distribution of specific MRSP lineages, their antimicrobial resistance phenotypes, and their association with clinical conditions may help us to understand the emergence and spread of MRSP in dogs. The aim of this study was to determine the yearly proportions of MRSP lineages and their antimicrobial-resistant phenotypes in the Netherlands and to examine possible associations with clinical conditions. MRSP was first isolated from a canine specimen submitted for diagnostics to the Faculty of Veterinary Medicine of Utrecht University in 2004. The annual cumulative incidence of MRSP among S. pseudintermedius increased from 0.9% in 2004 to 7% in 2013. MRSP was significantly associated with pyoderma and, to a lesser extent, with wound infections and otitis externa. Multilocus sequence typing (MLST) of 478 MRSP isolates yielded 39 sequence types (ST) belonging to 4 clonal complexes (CC) and 15 singletons. CC71 was the dominant lineage that emerged since 2004, and CC258, CC45, and several unlinked isolates became more frequent during the following years. All but two strains conferred an MDR phenotype, but strains belonging to CC258 or singletons were less resistant. In conclusion, our study showed that MDR CC71 emerged as the dominant lineage from 2004 and onward and that less-resistant lineages were partly replacing CC71.

  2. Genotypic and phenotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) clones with high-level mupirocin resistance.

    PubMed

    González-Domínguez, María; Seral, Cristina; Potel, Carmen; Sáenz, Yolanda; Álvarez, Maximiliano; Torres, Carmen; Castillo, Francisco Javier

    2016-06-01

    A high proportion of methicillin-resistant Staphylococcus aureus isolates recovered in one year period showed high-level mupirocin-resistance (HLMUPR-MRSA) in our environment (27.2%). HLMUPR-MRSA isolates were mainly collected from skin and soft tissue samples, and diabetes was the main related comorbidity condition. These isolates were more frequently found in vascular surgery. HLMUPR-MRSA was more resistant to aminoglycosides than mupirocin-susceptible MRSA, linked to the presence of bifunctional and/or nucleotidyltransferase enzymes with/without macrolide resistance associated with the msr(A) gene. Most of HLMUPR-MRSA isolates belonged to ST125/t067. Nine IS257-ileS2 amplification patterns (p3 was the most frequent) were observed in HLMUPR-MRSA isolates, suggesting the presence of several mupirocin-resistance-carrying plasmids in our environment and promoting the emergence of mupirocin resistance. The presence of the same IS257-ileS2 amplification pattern p3 in 65% of HLMUPR-MRSA, all of them ST125/t067, suggests a clonal spread in our hospital and community environment which could explain the high prevalence of HLMUPR-MRSA during the study period. An outbreak situation or an increase in mupirocin consumption was not observed.

  3. [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 and agrCA) were investigated by polymerase chain reaction (PCR). The phenotypic properties of the isolates such as biofilm formation, antibiotic susceptibility, extracellular protease and lipase production were also evaluated. None of the isolates were found to be biofilm and/or slime producers, however, all strains were found to have icaA gene which is responsible for biofilm formation. Nevertheless the presence of icaC and bap genes that are also responsible for biofilm formation were not detected. All the strains have had mecA gene and were resistant to oxacillin, penicilin G and gentamicin, while 10 were also resistant to erythromycin and nine were also resistant to ofloxacin. The isolates were susceptible to vancomycin, teicoplanin and co-trimoxazole. Screening of toxin and regulatory genes revealed that all the strains harboured sea, set1, hla, hlb and sarA genes. The phenotypic tests for the determination of extracellular protease production revealed that all the strains formed very weak zones on skim milk and milk agar plates, and yielded negative results on casein agar plates. Furthermore, all strains were found to harbour sspA, sspB, aur and serine

  4. Excretion of antimicrobials used to treat methicillin-resistant Staphylococcus aureus infections during lactation: safety in breastfeeding infants.

    PubMed

    Mitrano, Jennifer A; Spooner, Linda M; Belliveau, Paul

    2009-09-01

    Community-acquired strains of methicillin-resistant Staphylococcus aureus (MRSA) have become a common cause of skin and soft tissue infections in the United States. These infections sometimes require treatment with antibiotics, and with the increasing resistance of pathogens to these agents, choosing the appropriate drug can be difficult. In lactating women who develop these infections, selecting an antibiotic is even more challenging, as clinicians need to be aware of risks to the infant from the drug excreted during lactation. To our knowledge, no review has addressed the safety of antibiotics in breastfeeding infants when the drugs are used to treat maternal skin and soft tissue infections from MRSA. Thus, we performed a literature search of the PubMed-MEDLINE and EMBASE databases (1974-March 2009), reviewed reference citations from identified publications, researched antibiotic prescribing information, and corresponded with drug manufacturers. Case reports, case series, and both in vivo and in vitro clinical trials were evaluated for the following antibiotics: clindamycin, daptomycin, linezolid, quinupristin-dalfopristin, rifampin, tetracycline, doxycycline, minocycline, tigecycline, trimethoprim-sulfamethoxazole, and vancomycin. Information for the newer antibiotics (linezolid, quinupristin-dalfopristin, tigecycline, and daptomycin) was limited. Despite heterogeneity in the data for the older antibiotics (clindamycin, rifampin, tetracyclines, trimethoprim-sulfamethoxazole, and vancomycin), all appear to be relatively safe in the minimal quantities nursing infants ingest through breast milk. Although the risk to infants seems to be relatively low for most of the agents we explored, the paucity of data indicates a need for close monitoring of breastfed infants whose mothers are receiving an antibiotic for an MRSA skin and soft tissue infection.

  5. Genotypic and phenotypic characteristics of Methicillin-resistant Staphylococcus aureus (MRSA) strains, isolated on three different geography locations

    PubMed Central

    Ostojić, Maja; Hukić, Mirsada

    2015-01-01

    Staphylococcus aureus is a major cause of hospital-acquired infections worldwide. Increased frequency of methicillin-resistant Staphylococcus aureus (MRSA) in hospitalized patients and possibility of vancomycin resistance requires rapid and reliable characterization of isolates and control of MRSA spread in hospitals. Typing of isolates helps to understand the route of a hospital pathogen spread. The aim of this study was to investigate and compare genotypic and phenotypic characteristics of MRSA samples on three different geography locations. In addition, our aim was to evaluate three different methods of MRSA typing: spa-typing, agr-typing and GenoType MRSA. We included 104 samples of MRSA, isolated in 3 different geographical locations in clinical hospitals in Zagreb, Mostar, and Heidelberg, during the period of six months. Genotyping and phenotyping were done by spa-typing, agr-typing and dipstick assay GenoType MRSA. We failed to type all our samples by spa-typing. The most common spa-type in clinical hospital Zagreb was t041, in Mostar t001, and in Heidelberg t003. We analyzed 102/104 of our samples by agr-typing method. We did not find any agr-type IV in our locations. We analyzed all our samples by the dipstick assay GenoType MRSA. All isolates in our study were MRSA strains. In Zagreb there were no positive strains to PVL gene. In Mostar we have found 5/25 positive strains to PVL gene, in Heidelberg there was 1/49. PVL positive isolates were associated with spa-type t008 and agr-type I, thus, genetically, they were community-associated MRSA (CA-MRSA). Dipstick assay GenoType MRSA has demonstrated sufficient specificity, sensibility, simple performance and low cost, so we could introduce it to work in smaller laboratories. Using this method may expedite MRSA screening, thus preventing its spread in hospitals. PMID:26295294

  6. Genotypic and phenotypic characteristics of Methicillin-resistant Staphylococcus aureus (MRSA) strains, isolated on three different geography locations.

    PubMed

    Ostojić, Maja; Hukić, Mirsada

    2015-08-04

    Staphylococcus aureus is a major cause of hospital-acquired infections worldwide. Increased frequency of methicillin-resistant Staphylococcus aureus (MRSA) in hospitalized patients and possibility of vancomycin resistance requires rapid and reliable characterization of isolates and control of MRSA spread in hospitals. Typing of isolates helps to understand the route of a hospital pathogen spread. The aim of this study was to investigate and compare genotypic and phenotypic characteristics of MRSA samples on three different geography locations. In addition, our aim was to evaluate three different methods of MRSA typing: spa-typing, agr-typing and GenoType MRSA.  We included 104 samples of MRSA, isolated in 3 different geographical locations in clinical hospitals in Zagreb, Mostar, and Heidelberg, during the period of six months. Genotyping and phenotyping were done by spa-typing, agr-typing and dipstick assay GenoType MRSA. We failed to type all our samples by spa-typing.  The most common spa-type in clinical hospital Zagreb was t041, in Mostar t001, and in Heidelberg t003.We analyzed 102/104 of our samples by agr-typing method. We did not find any agr-type IV in our locations. We analyzed all our samples by the dipstick assay GenoType MRSA. All isolates in our study were MRSA strains. In Zagreb there were no positive strains to PVL gene. In Mostar we have found 5/25 positive strains to PVL gene, in Heidelberg there was 1/49. PVL positive isolates were associated with spa-type t008 and agr-type I, thus, genetically, they were community-associated MRSA (CA-MRSA). Dipstick assay GenoType MRSA has demonstrated sufficient specificity, sensibility, simple performance and low cost, so we could introduce it to work in smaller laboratories. Using this method may expedite MRSA screening, thus preventing its spread in hospitals.

  7. Predictors of community-associated Staphylococcus aureus, methicillin-resistant and methicillin-susceptible Staphylococcus aureus skin and soft tissue infections in primary-care settings.

    PubMed

    Lee, G C; Hall, R G; Boyd, N K; Dallas, S D; DU, L C; Treviño, L B; Retzloff, C; Treviño, S B; Lawson, K A; Wilson, J P; Olsen, R J; Wang, Y; Frei, C R

    2016-11-01

    Skin and soft tissue infections (SSTIs) due to Staphylococcus aureus have become increasingly common in the outpatient setting; however, risk factors for differentiating methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) SSTIs are needed to better inform antibiotic treatment decisions. We performed a case-case-control study within 14 primary-care clinics in South Texas from 2007 to 2015. Overall, 325 patients [S. aureus SSTI cases (case group 1, n = 175); MRSA SSTI cases (case group 2, n = 115); MSSA SSTI cases (case group 3, n = 60); uninfected control group (control, n = 150)] were evaluated. Each case group was compared to the control group, and then qualitatively contrasted to identify unique risk factors associated with S. aureus, MRSA, and MSSA SSTIs. Overall, prior SSTIs [adjusted odds ratio (aOR) 7·60, 95% confidence interval (CI) 3·31-17·45], male gender (aOR 1·74, 95% CI 1·06-2·85), and absence of healthcare occupation status (aOR 0·14, 95% CI 0·03-0·68) were independently associated with S. aureus SSTIs. The only unique risk factor for community-associated (CA)-MRSA SSTIs was a high body weight (⩾110 kg) (aOR 2·03, 95% CI 1·01-4·09).

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Vancomycin for the treatment of methicillin-resistant staphylococcal and enterococcal infections in 15 horses

    PubMed Central

    2005-01-01

    Abstract We retrospectively reviewed the cases of 15 foals and adult horses in which vancomycin was used, alone or in combination with an aminoglycoside, to treat methicillin-resistant staphylococcal and enterococcal infections. Signalment, presenting complaint, history (including history of treatment for the current complaint), results of bacterial culture and antimicrobial susceptibility testing, treatment, and outcome were reviewed. The average vancomycin dosage was 7.5 mg/kg q8h, administered by intravenous infusion over 30 min. The infection resolved in all 7 horses with soft tissue infections and in 6 of the 8 horses with infections involving a bone or a joint, or both. No adverse effects of vancomycin therapy were noted. Although the number of cases is small, our findings suggest that vancomycin, alone or in combination with an aminoglycoside, is safe and effective for the treatment of resistant staphylococcal and enterococcal infections in horses and foals. However, owing to the importance of staphylococci and enterococci in human medicine and the problems with emerging resistance, we recommend that the use of vancomycin in horses be limited to cases in which culture and susceptibility results clearly indicate that this agent is likely to be effective and in which there is no reasonable alternative. PMID:16479726

  15. 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.

  16. 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.

  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. Spread of methicillin-resistant Staphylococcus aureus belonging to the Brazilian epidemic clone in a general hospital and emergence of heterogenous resistance to glycopeptide antibiotics among these isolates.

    PubMed

    dos Santos Soares, M J; da Silva-Carvalho, M C; Ferreira-Carvalho, B T; Figueiredo, A M

    2000-04-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections have been increasing at an alarming rate world-wide. MRSA epidemics due to the clonal spread of multi-resistant isolates have been described. In this paper we show the absolute predominance of MRSA strains from the Brazilian epidemic clone in a hospital in the Northeast region of Brazil and the emergence of a vancomycin and teicoplanin heterogeneous resistant subpopulation among these isolates.

  19. Methicillin-Resistant Staphylococcus aureus in Commercial Swine Herds Is Associated with Disinfectant and Zinc Usage

    PubMed Central

    Friendship, Robert M.; Weese, J. Scott

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) originating from swine is concerning for public health, but an understanding of the emergence and persistence of MRSA in nursery herds is lacking. The aim of this study was to determine whether MRSA in nursery pigs is associated with particular herd-level parameters, including the use of antimicrobials, disinfectants, and heavy metals, which may be driving the selection and persistence of antimicrobial resistance. Nasal cultures for MRSA were completed for 390 pigs from 26 farms at the end of the suckling phase and again at 3 weeks postweaning. Herd-level information was collected, and a random subset of MRSA isolates was screened for resistance to zinc and quaternary ammonium compounds (QACs). Multivariate analysis revealed that in-feed concentrations of zinc (P < 0.001) and frequent disinfection of nursery pens (P < 0.001) are associated with MRSA shedding in nursery pigs. Furthermore, 62.5% (25/40) of MRSA isolates carried the zinc resistance gene czrC and demonstrated decreased susceptibility to zinc. All MRSA isolates carried at least 1 QAC resistance gene. The most common genotype was qacG qacH smr, which occurred in 32.5% (13/40) of isolates. Seven isolates (17.5%) demonstrated a significant tolerance to benzalkonium chloride, indicating a potential to survive commercial QAC exposure in the presence of organic matter. Overall, these findings indicate that high levels of in-feed zinc and QAC-based disinfectants are important drivers in the selection and persistence of MRSA in commercial swine herds, and these agents may be coselecting for other antimicrobial resistance genes. PMID:25662976

  20. The effect of essential oils on methicillin-resistant Staphylococcus aureus using a dressing model.

    PubMed

    Edwards-Jones, V; Buck, R; Shawcross, S G; Dawson, M M; Dunn, K

    2004-12-01

    Patchouli, tea tree, geranium, lavender essential oils and Citricidal (grapefruit seed extract) were used singly and in combination to assess their anti-bacterial activity against three strains of Staphylococcus aureus: Oxford S. aureus NCTC 6571 (Oxford strain), Epidemic methicillin-resistant S. aureus (EMRSA 15) and MRSA (untypable). The individual essential oils, extracts and combinations were impregnated into filter paper discs and placed on the surface of agar plates, pre-seeded with the appropriate strain of Staphylococcus. The effects of the vapours of the oils and oil combinations were also assessed using impregnated filter paper discs that were placed on the underside of the Petri dish lid at a distance of 8mm from the bacteria. The most inhibitory combinations of oils for each strain were used in a dressing model constructed using a four layers of dressings: the primary layer consisted of either Jelonet or TelfaClear with or without Flamazine; the second was a layer of gauze, the third a layer of Gamgee and the final layer was Crepe bandage. The oil combinations were placed in either the gauze or the Gamgee layer. This four-layered dressing was placed over the seeded agar plate, incubated for 24h at 37 degrees C and the zones of inhibition measured. All experiments were repeated on three separate occasions. No anti-bacterial effects were observed when Flamazine was smeared on the gauze in the dressing model. When Telfaclear was used as the primary layer in the dressing model compared to Jelonet, greater zones of inhibition were observed. A combination of Citricidal and geranium oil showed the greatest-anti-bacterial effects against MRSA, whilst a combination of geranium and tea tree oil was most active against the methicillin-sensitive S. aureus (Oxford strain). This study demonstrates the potential of essential oils and essential oil vapours as antibacterial agents and for use in the treatment of MRSA infection.

  1. Combinations of β-Lactam or Aminoglycoside Antibiotics with Plectasin Are Synergistic against Methicillin-Sensitive and Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Hu, Yanmin; Liu, Alexander; Vaudrey, James; Vaiciunaite, Brigita; Moigboi, Christiana; McTavish, Sharla M.; Kearns, Angela; Coates, Anthony

    2015-01-01

    Bacterial infections remain the leading killer worldwide which is worsened by the continuous emergence of antibiotic resistance. In particular, methicillin-sensitive (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) are prevalent and the latter can be difficult to treat. The traditional strategy of novel therapeutic drug development inevitably leads to emergence of resistant strains, rendering the new drugs ineffective. Therefore, rejuvenating the therapeutic potentials of existing antibiotics offers an attractive novel strategy. Plectasin, a defensin antimicrobial peptide, potentiates the activities of other antibiotics such as β-lactams, aminoglycosides and glycopeptides against MSSA and MRSA. We performed in vitro and in vivo investigations to test against genetically diverse clinical isolates of MSSA (n = 101) and MRSA (n = 115). Minimum inhibitory concentrations (MIC) were determined by the broth microdilution method. The effects of combining plectasin with β-lactams, aminoglycosides and glycopeptides were examined using the chequerboard method and time kill curves. A murine neutropenic thigh model and a murine peritoneal infection model were used to test the effect of combination in vivo. Determined by factional inhibitory concentration index (FICI), plectasin in combination with aminoglycosides (gentamicin, neomycin or amikacin) displayed synergistic effects in 76-78% of MSSA and MRSA. A similar synergistic response was observed when plectasin was combined with β-lactams (penicillin, amoxicillin or flucloxacillin) in 87–89% of MSSA and MRSA. Interestingly, no such interaction was observed when plectasin was paired with vancomycin. Time kill analysis also demonstrated significant synergistic activities when plectasin was combined with amoxicillin, gentamicin or neomycin. In the murine models, plectasin at doses as low as 8 mg/kg augmented the activities of amoxicillin and gentamicin in successful treatment of MSSA and MRSA infections. We

  2. Daptomycin efficacy in the central nervous system of a patient with disseminated methicillin-resistant Staphylococcus aureus infection: a case report

    PubMed Central

    2012-01-01

    Introduction Staphylococcus aureus has emerged as a major nosocomial pathogen in the last decades and also represents the second most common pathogen isolated from patients in outpatient settings. Although methicillin-resistant S.aureus infections were traditionally limited to hospitals, community-associated cases of methicillin-resistant S.aureus infections have been reported. In our case, we observed an unexpected event during treatment. Case presentation A 60-year-old Caucasian man developed fever and multiple muscle and brain abscesses caused by Panton-Valentine leukocidin-negative community-associated methicillin-resistant S. aureus. Conclusion Although our patient was given antimicrobials active against the isolated methicillin-resistant S. aureus strain, it was only after the introduction of daptomycin that his skin, soft tissue and muscle lesions and also brain manifestations improved. PMID:22938025

  3. Co-infection of methicillin-resistant Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus and extended spectrum β-lactamase producing Escherichia coli in bovine mastitis--three cases reported from India.

    PubMed

    Bandyopadhyay, Samiran; Samanta, Indranil; Bhattacharyya, Debaraj; Nanda, Pramod Kumar; Kar, Debasish; Chowdhury, Jayanta; Dandapat, Premanshu; Das, Arun Kumar; Batul, Nayan; Mondal, Bimalendu; Dutta, Tapan Kumar; Das, Gunjan; Das, Bikash Chandra; Naskar, Syamal; Bandyopadhyay, Uttam Kumar; Das, Suresh Chandra; Bandyopadhyay, Subhasish

    2015-03-01

    Emergence of antimicrobial resistance among bovine mastitis pathogens is the major cause of frequent therapeutic failure and a cause of concern for veterinary practitioners. This study describes intra-mammary infection of methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum β-lactamase (ESBL) producing Escherichia coli in two Holstein Friesian crossbred cows with subclinical mastitis and one non-descript cow with clinical mastitis in two different districts of West Bengal, India. In total, three MRSE, one MRSA and three ESBL producing E. coli were isolated from these cases. Both the crossbreds were detected with MRSE (HFSE1 and HFSE2) and ESBL producing E. coli (HFEC1 and HFEC2), whereas, simultaneous infection of three pathogens viz. MRSA (NDSA1), MRSE (NDSE1) and ESBL producing E. coli (NDEC1) was found in the non-descript cow. The methicillin-resistant isolates possessed mecA gene and exhibited resistance to various antibiotics such as amikacin, tetracycline and glycopeptides. The ESBL producers were positive for blaCTX-M and blaTEM genes; in addition, HFEC1 and HFEC2 were positive for blaSHV and possessed the genes for class I integron (int1), sulphonamide resistance (sul1), quinolone resistance (qnrS) and other virulence factors (papC, iucD and ESTA1). All the ESBL producers exhibited resistance to a variety of antibiotics tested including third- and fourth-generation cephalosporins and were also intermediately resistant to carbapenems. This is the first ever report on simultaneous occurrence of MRSE, MRSA and ESBL producing E. coli in bovine mastitis indicating a major concern for dairy industry and public health as well.

  4. Differences in hospital- and ventilator-associated pneumonia due to Staphylococcus aureus (methicillin-susceptible and methicillin-resistant) between Europe and Latin America: A comparison of the EUVAP and LATINVAP study cohorts

    PubMed Central

    Rello, J.; Molano, D.; Villabon, M.; Reina, R.; Rita-Quispe, R.; Previgliano, I.; Afonso, E.; Restrepo, M.I.

    2014-01-01

    Purpose A comparison is made of epidemiological variables (demographic and clinical characteristics) and outcomes in patients with hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP) caused by methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) in the Latin American VAP (LATINVAP) vs. the European Union VAP (EUVAP) cohorts of patients admitted to intensive care units (ICUs). Methods The EUVAP project was a prospective, multicenter observational study reporting 827 patients with HAP/VAP in 27 ICUs from 9 European countries. The LATINVAP project was a multicenter prospective observational study, with an identical design, performed in 17 ICUs from 4 Latin American countries involving 99 patients who developed HAP/VAP. Episodes of VAP/HAP caused by S. aureus, MSSA, and MRSA were compared in both cohorts. Results Forty-five patients had S. aureus HAP/VAP in the EUVAP cohort vs. 11 patients in the LATINVAP cohort. More patients had MRSA in the LATINVAP study than in the EUVAP (45% vs. 33%). ICU mortality among patients with MSSA HAP/VAP in EUVAP was 10% vs. 50% for LATINVAP (OR = 9.75, p = 0.01). Fifteen patients in the EUVAP cohort developed MRSA HAP/VAP as opposed to 5 in LATINVAP. In the EUVAP study there was an ICU mortality rate of 33.3%. In the LATINVAP cohort, the ICU mortality rate was 60% (OR for death = 3.0; 95%CI 0.24–44.7). Conclusion MRSA pneumonia was associated with poorer outcomes in comparison with MSSA. Our study suggests significant variability among European and Latin American ICU practices that may influence clinical outcomes. Furthermore, patients with pneumonia in Latin America have different outcomes. PMID:22749536

  5. Fermentation of Propionibacterium acnes, a commensal bacterium in the human skin microbiome, as skin probiotics against methicillin-resistant Staphylococcus aureus.

    PubMed

    Shu, Muya; Wang, Yanhan; Yu, Jinghua; Kuo, Sherwin; Coda, Alvin; Jiang, Yong; Gallo, Richard L; Huang, Chun-Ming

    2013-01-01

    Bacterial interference creates an ecological competition between commensal and pathogenic bacteria. Through fermentation of milk with gut-friendly bacteria, yogurt is an excellent aid to balance the bacteriological ecosystem in the human intestine. Here, we demonstrate that fermentation of glycerol with Propionibacterium acnes (P. acnes), a skin commensal bacterium, can function as a skin probiotic for in vitro and in vivo growth suppression of USA300, the most prevalent community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). We also promote the notion that inappropriate use of antibiotics may eliminate the skin commensals, making it more difficult to fight pathogen infection. This study warrants further investigation to better understand the role of fermentation of skin commensals in infectious disease and the importance of the human skin microbiome in skin health.

  6. Detection and molecular characterization of a gentamicin-susceptible, methicillin-resistant Staphylococcus aureus (MRSA) clone in Rio de Janeiro that resembles the New York/Japanese clone.

    PubMed

    Melo, M C N; Silva-Carvalho, M C; Ferreira, R L; Coelho, L R; Souza, R R; Gobbi, C N; Rozenbaum, R; Solari, C A; Ferreira-Carvalho, B T; Figueiredo, A M S

    2004-12-01

    Staphylococcus aureus is the leading cause of hospital-acquired infections in many countries, and multiple factors contribute to the ability of these bacteria to disseminate and spread in hospitals. In Brazil it has been demonstrated that a multiresistant methicillin-resistant S. aureus clone, the so-called Brazilian epidemic clone, is widespread geographically. This clone was first detected in 1992 in Brazil, and recently from many other countries within South America, Europe and Asia. The study describes the detection of a gentamicin-susceptible heterogeneous MRSA clone that resembles another MRSA clone widely spread in US and Japanese hospitals, and supports the premise that the detection of heterogeneous MRSA isolates by some recommended methods is a challenging task that may, occasionally, result in MRSA misidentification.

  7. Occurrence, species distribution, antimicrobial resistance and clonality of methicillin- and erythromycin-resistant staphylococci in the nasal cavity of domestic animals.

    PubMed

    Bagcigil, Funda A; Moodley, Arshnee; Baptiste, Keith E; Jensen, Vibeke F; Guardabassi, Luca

    2007-04-15

    beta-Lactams and macrolides are important antibiotics for treatment of staphylococcal infections in both humans and animals. The aim of the study was to investigate the occurrence, species distribution and clonality of methicillin- and erythromycin-resistant staphylococci in the nasal cavity of dogs, horses, pigs, and cattle in Denmark. Nasal swabs were collected from a total of 400 animals, including 100 individuals of each species. Methicillin- and erythromycin-resistant staphylococci were isolated on selective media, identified by 16S rDNA sequencing, and typed by pulsed field gel electrophoresis (PFGE). Methicillin-resistant coagulase-negative staphylococci (MRCoNS) harbouring mecA were isolated from horses (50%) and dogs (13%), but not from food animals. The species identified were S. haemolyticus (n=21), S. vitulinus (n=19), S. sciuri (n=13), S. epidermidis (n=8), and S. warneri (n=2). mecA-mediated methicillin resistance in S. vitulinus was described for the first time. Methicillin-resistant S. aureus was not detected. PFGE analysis revealed the presence of specific MRCoNS clones in samples originating from the same veterinary hospital or equine farm. Erythromycin-resistant S. aureus (ERSA) was detected in 38% of pigs and all isolates harboured a constitutively expressed erm(C) gene. The vast majority (37/38) of pigs carrying ERSA originated from a farm characterized by frequent use of macrolides. Most ERSA isolates (28/38) displayed indistinguishable or closely related PFGE patterns, indicating clonal distribution within the farm. Based on the analysis of data on antimicrobial consumption, the occurrence of MRCoNS in companion animals and that of ERSA in pigs reflected national and local patterns of antimicrobial usage.

  8. Antimicrobial resistance and virulence markers in methicillin sensitive Staphylococcus aureus isolates associated with nasal colonization.

    PubMed

    Sarkar, Abdullah; Raji, Adeola; Garaween, Ghada; Soge, Olusegun; Rey-Ladino, Jose; Al-Kattan, Wael; Shibl, Atef; Senok, Abiola

    2016-04-01

    Most Staphylococcus aureus infections occur in previously colonized persons who also act as reservoirs for continued dissemination. This study aimed to investigate the carriage of antimicrobial resistance and virulence markers in S. aureus isolates associated with nasal colonization. The study was conducted from December 2013-April 2014. Nasal swabs were collected and questionnaires administered to 97 medical students in Riyadh Saudi Arabia. Bacterial culture, identification and antimicrobial susceptibility testing were performed by conventional methods and chromogenic agar was used for methicillin resistant S. aureus (MRSA) screening. Molecular characterization of isolates was carried out using the StaphyType DNA microarray. Thirty two students (43%) had S. aureus nasal carriage (MSSA = 31; MRSA = 1). Seventeen clonal complexes (CC) were identified namely: CC15-MSSA (n = 5), CC1-MSSA-SCCfus (n = 4), CC8-MSSA (n = 3), CC22-MSSA (n = 3), CC25-MSSA (n = 3), CC101-MSSA (n = 2). Other CC found as single isolates were CC5-MSSA, CC6-MSSA, CC30-MSSA, CC45-MSSA, CC96-MSSA, CC188-MSSA, CC398-MSSA, CC942-MSSA/PVL+, CC1290-MSSA, ST2482-MSSA, CC80-MRSA-IV/PVL+. The CC1-SCCfus isolates harbored the Staphylococcal cassette chromosome (SCC) with ccrA-1; ccrB-1 and ccrB-3 genes plus the putative fusidic acid resistance marker Q6GD50. One MSSA isolate was genotyped as coagulase negative Staphylococcus spp with an irregular composite SCCmec element. Majority of the isolates harbored various virulence genes including the hemolysin, enterotoxin, and exfoliative genes as well as various adhesive protein producing genes. Although there was low carriage of MRSA, the MSSA isolates harbored various resistance and virulence genes including those usually seen in MRSA isolates. The presence of isolates with incomplete SCCmec elements plus putative resistance and virulence genes is of concern.

  9. Isolation and characterization of methicillin-resistant Staphylococcus aureus from pork farms and visiting veterinary students.

    PubMed

    Frana, Timothy S; Beahm, Aleigh R; Hanson, Blake M; Kinyon, Joann M; Layman, Lori L; Karriker, Locke A; Ramirez, Alejandro; Smith, Tara C

    2013-01-01

    In the last decade livestock-associated methicillin-resistant S. aureus (LA-MRSA) has become a public health concern in many parts of the world. Sequence type 398 (ST398) has been the most commonly reported type of LA-MRSA. While many studies have focused on long-term exposure experienced by swine workers, this study focuses on short-term exposures experienced by veterinary students conducting diagnostic investigations. The objectives were to assess the rate of MRSA acquisition and longevity of carriage in students exposed to pork farms and characterize the recovered MRSA isolates. Student nasal swabs were collected immediately before and after farm visits. Pig nasal swabs and environmental sponge samples were also collected. MRSA isolates were identified biochemically and molecularly including spa typing and antimicrobial susceptibility testing. Thirty (30) veterinary students were enrolled and 40 pork farms were visited. MRSA was detected in 30% of the pork farms and in 22% of the students following an exposure to a MRSA-positive pork farm. All students found to be MRSA-positive initially following farm visit were negative for MRSA within 24 hours post visit. Most common spa types recovered were t002 (79%), t034 (16%) and t548 (4%). Spa types found in pork farms closely matched those recovered from students with few exceptions. Resistance levels to antimicrobials varied, but resistance was most commonly seen for spectinomycin, tetracyclines and neomycin. Non-ST398 MRSA isolates were more likely to be resistant to florfenicol and neomycin as well as more likely to be multidrug resistant compared to ST398 MRSA isolates. These findings indicate that MRSA can be recovered from persons visiting contaminated farms. However, the duration of carriage was very brief and most likely represents contamination of nasal passages rather than biological colonization. The most common spa types found in this study were associated with ST5 and expands the range of livestock

  10. Antibiotic reduction campaigns do not necessarily decrease bacterial resistance: the example of methicillin-resistant Staphylococcus aureus.

    PubMed

    Kardas-Sloma, Lidia; Boëlle, Pierre-Yves; Opatowski, Lulla; Guillemot, Didier; Temime, Laura

    2013-09-01

    Interventions designed to reduce antibiotic consumption are under way worldwide. While overall reductions are often achieved, their impact on the selection of antibiotic-resistant selection cannot be assessed accurately from currently available data. We developed a mathematical model of methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) transmission inside and outside the hospital. A systematic simulation study was then conducted with two objectives: to assess the impact of antibiotic class-specific changes during an antibiotic reduction period and to investigate the interactions between antibiotic prescription changes in the hospital and the community. The model reproduced the overall reduction in MRSA frequency in French intensive-care units (ICUs) with antibiotic consumption in France from 2002 to 2003 as an input. However, the change in MRSA frequency depended on which antibiotic classes changed the most, with the same overall 10% reduction in antibiotic use over 1 year leading to anywhere between a 69% decrease and a 52% increase in MRSA frequency in ICUs and anywhere between a 37% decrease and a 46% increase in the community. Furthermore, some combinations of antibiotic prescription changes in the hospital and the community could act in a synergistic or antagonistic way with regard to overall MRSA selection. This study shows that class-specific changes in antibiotic use, rather than overall reductions, need to be considered in order to properly anticipate the impact of an antibiotic reduction campaign. It also highlights the fact that optimal gains will be obtained by coordinating interventions in hospitals and in the community, since the effect of an intervention in a given setting may be strongly affected by exogenous factors.

  11. Characterization of Methicillin-Resistant Staphylococcus aureus Isolated from Healthy Turkeys and Broilers Using DNA Microarrays.

    PubMed

    El-Adawy, Hosny; Ahmed, Marwa; Hotzel, Helmut; Monecke, Stefan; Schulz, Jochen; Hartung, Joerg; Ehricht, Ralf; Neubauer, Heinrich; Hafez, Hafez M

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a major human health problem and recently, domestic animals are described as carriers and possible reservoirs. Twenty seven S. aureus isolates from five turkey farms (n = 18) and two broiler farms (n = 9) were obtained by culturing of choana and skin swabs from apparently healthy birds, identified by Taqman-based real-time duplex nuc-mecA-PCR and characterized by spa typing as well as by a DNA microarray based assay which covered, amongst others, a considerable number of antibiotic resistance genes, species controls, and virulence markers. The antimicrobial susceptibility profiles were tested by agar diffusion assays and genotypically confirmed by the microarray. Five different spa types (3 in turkeys and 2 in broilers) were detected. The majority of MRSA isolates (24/27) belonged to clonal complex 398-MRSA-V. The most frequently occurring spa types were accordingly t011, t034, and t899. A single CC5-MRSA-III isolated from turkey and CC398-MRSA with an unidentified/truncated SCCmec element in turkey and broiler were additionally detected. The phenotypic antimicrobial resistance profiles of S. aureus isolated from both turkeys and broilers against 14 different antimicrobials showed that all isolates were resistant to ampicillin, cefoxitin, oxacillin, doxycycline, and tetracycline. Moreover, all S. aureus isolated from broilers were resistant to erythromycin and azithromycin. All isolates were susceptible to gentamicin, chloramphenicol, sulphonamides, and fusidic acid. The resistance rate against ciprofloxacin was 55.6% in broiler isolates and 42.1% in turkey isolates. All tetracycline resistant isolates possessed genes tetK/M. All erythromycin-resistant broiler isolates carried ermA. Only one broiler isolate (11.1%) carried genes ermA, ermB, and ermC, while 55.6% of turkey isolates possessed ermA and ermB genes. Neither PVL genes (lukF/S-PV), animal-associated leukocidin (lukM and luk-P83) nor the gene encoding

  12. Characterization of Methicillin-Resistant Staphylococcus aureus Isolated from Healthy Turkeys and Broilers Using DNA Microarrays

    PubMed Central

    El-Adawy, Hosny; Ahmed, Marwa; Hotzel, Helmut; Monecke, Stefan; Schulz, Jochen; Hartung, Joerg; Ehricht, Ralf; Neubauer, Heinrich; Hafez, Hafez M.

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a major human health problem and recently, domestic animals are described as carriers and possible reservoirs. Twenty seven S. aureus isolates from five turkey farms (n = 18) and two broiler farms (n = 9) were obtained by culturing of choana and skin swabs from apparently healthy birds, identified by Taqman-based real-time duplex nuc-mecA-PCR and characterized by spa typing as well as by a DNA microarray based assay which covered, amongst others, a considerable number of antibiotic resistance genes, species controls, and virulence markers. The antimicrobial susceptibility profiles were tested by agar diffusion assays and genotypically confirmed by the microarray. Five different spa types (3 in turkeys and 2 in broilers) were detected. The majority of MRSA isolates (24/27) belonged to clonal complex 398-MRSA-V. The most frequently occurring spa types were accordingly t011, t034, and t899. A single CC5-MRSA-III isolated from turkey and CC398-MRSA with an unidentified/truncated SCCmec element in turkey and broiler were additionally detected. The phenotypic antimicrobial resistance profiles of S. aureus isolated from both turkeys and broilers against 14 different antimicrobials showed that all isolates were resistant to ampicillin, cefoxitin, oxacillin, doxycycline, and tetracycline. Moreover, all S. aureus isolated from broilers were resistant to erythromycin and azithromycin. All isolates were susceptible to gentamicin, chloramphenicol, sulphonamides, and fusidic acid. The resistance rate against ciprofloxacin was 55.6% in broiler isolates and 42.1% in turkey isolates. All tetracycline resistant isolates possessed genes tetK/M. All erythromycin-resistant broiler isolates carried ermA. Only one broiler isolate (11.1%) carried genes ermA, ermB, and ermC, while 55.6% of turkey isolates possessed ermA and ermB genes. Neither PVL genes (lukF/S-PV), animal-associated leukocidin (lukM and luk-P83) nor the gene encoding

  13. Characteristics of methicillin resistant Staphylococcus aureus isolated from chicken meat and hospitalized dogs in Korea and their epidemiological relatedness.

    PubMed

    Kwon, Nam Hoon; Park, Kun Taek; Jung, Woo Kyung; Youn, Hwa Young; Lee, Yeonhee; Kim, So Hyun; Bae, Wonki; Lim, Ji Youn; Kim, Ji Yeon; Kim, Jun Man; Hong, Soon Keun; Park, Yong Ho

    2006-10-31

    Methicillin resistant Staphylococcus aureus (MRSA) is one of the most important pathogens in human and veterinary hospitals. The isolation of MRSA from animals and foodstuffs has been reported with an increased incidence. However, methicillin (oxacillin) is not used in animal husbandry or in animal hospitals in Korea. In this study, three pre-MRSA and one silent mecA-carrying methicillin susceptible S. aureus (smMSSA) were isolated from retail chicken meat, and three MRSA were isolated from hospitalized dogs in Korea. The three pre-MRSA isolates were determined to have a staphylococcal cassette chromosome mec (SCCmec) type III, and the smMSSA isolate was not classified. The animal hospital isolates were found to contain SCCmec type II. Seven and 15 S. aureus isolated from hospitalized humans and bovine milk, respectively, were also examined in this study in order to determine the epidemiological origins of MRSA. Multilocus sequencing typing (MLST) revealed that the chicken meat and bovine milk isolates were closely related to the animal hospital isolates. The SCCmec characteristics and MLST analyses indicated the possibility of the human to animal transmission of MRSA. These results highlight the importance of identifying MRSA carriers as well as intercepting MRSA transmission because MRSA is becoming increasingly widespread without any plausible relationship with the use of methicillin (oxacillin).

  14. Discrimination of methicillin-resistant Staphylococcus aureus from methicillin-susceptible Staphylococcus aureus or coagulase-negative staphylococci by detection of penicillin-binding protein 2 and penicillin-binding protein 2' using a bioluminescent enzyme immunoassay.

    PubMed

    Shiga, Kazuki; Gomi, Keiko; Nishimura, Motoi; Watanabe, Masaharu; Nomura, Fumio; Kajiyama, Naoki

    2013-02-28

    For the discrimination of methicillin-resistant S. aureus (MRSA) from methicillin-susceptible S. aureus (MSSA) or coagulase-negative staphylococci (CNS), we developed a bioluminescent enzyme immunoassay (BLEIA) for detecting penicillin-binding protein 2 (PBP2) and penicillin-binding protein 2' (PBP2') using biotinylated firefly luciferase. The BLEIA was able to detect recombinant PBP2 at 50 pg/ml and recombinant PBP2' at 500 pg/ml. PBP2 and PBP2' present in the membranes of S. aureus were extracted by acid and detergent treatment. The method was able to detect PBP2 or PBP2' extracted from 10(6) colony forming units of S. aureus because of efficient extraction and the high sensitivity of luciferase. In a study of clinical isolates previously characterized as either MRSA or MSSA by antibiotic susceptibility testing, all 34 specimens identified as MRSA were both PBP2 and PBP2' positive. The 34 MSSA specimens were PBP2 positive and PBP2' negative. Moreover, the BLEIA could detect PBP2' extracted from four species of methicillin-resistant CNS, but not PBP2 extracted from four species of methicillin-resistant and methicillin-susceptible CNS. This result suggested that PBP2 could be a unique marker for discrimination of S. aureus from CNS. A BLEIA that is able to detect PBP2 and PBP2' may be useful in clinical diagnostics.

  15. Detection of methicillin-resistant Staphylococcus aureus directly by loop-mediated isothermal amplification and direct cefoxitin disk diffusion tests.

    PubMed

    Metwally, L; Gomaa, N; Hassan, R

    2014-05-01

    We evaluated the utility of 2 methods for detection of methicillin-resistant Staphylococcus aureus (MRSA) directly from signal-positive blood culture bottles: loop-mediated isothermal amplification (LAMP) assay, and direct cefoxitin disk diffusion (DCDD) test using a 30 μg cefoxitin disk. In parallel, standard microbiological identification and oxacillin susceptibility testing with MecA PCR was performed. Of 60 blood cultures positive for Gram-positive cocci in clusters, LAMP (via detection of the FemA and MecA genes) showed 100% sensitivity and specificity for identification of MRSA/MSSA. When coagulase-negative staphylococci were tested, sensitivity for detection of methicillin resistance was 91.7% and specificity was 100%. DCDD along with direct tube coagulase assay detected only 80.6% of MRSA/MSSA. LAMP showed higher diagnostic accuracy although DCDD was more cost-effective and did not require additional reagents or supplies.

  16. Daptomycin and rifampin for the treatment of methicillin-resistant Staphylococcus aureus septic pulmonary emboli in the absence of endocarditis.

    PubMed

    Gomez, Eric O; Jafary, Ahmar; Dever, Lisa L

    2010-09-01

    Daptomycin has demonstrated clinical efficacy in the treatment of methicillin-resistant Staphylococcus aureus-associated bacteremia and right-sided infective endocarditis. Although daptomycin is not approved for treatment of gram-positive pneumonia, clinical evidence suggests that it may be effective therapy for S. aureus-associated septic pulmonary emboli (SPE). We present our clinical experience with the use of daptomycin in combination with rifampin in four patients with SPE in the absence of infective endocarditis. Three of the patients had a history of injection drug use; two of these patients also had soft-tissue infections. All patients had clinical resolution of their infections. Daptomycin and rifampin appear to have a role in the treatment of methicillin-resistant S. aureus bacteremia with SPE in the absence of infective endocarditis and should be considered in patients that have failed therapy with vancomycin.

  17. PBP-2 Negative Methicillin Resistant Staphylococcus schleiferi Bacteremia from a Prostate Abscess: An Unusual Occurrence

    PubMed Central

    Merchant, Chandni; Villanueva, Daphne-Dominique; Lalani, Ishan; Eng, Margaret; Kang, Yong

    2016-01-01

    Staphylococcus schleiferi subsp. schleiferi is a coagulase-negative Staphylococcus which has been described as a pathogen responsible for various nosocomial infections including bacteremia, brain abscess, and infection of intravenous pacemakers. Recently, such bacteria have been described to be found typically on skin and mucosal surfaces. It is also believed to be a part of the preaxillary human flora and more frequently found in men. It is very similar in its pathogenicity with Staphylococcus aureus group and expresses a fibronectin binding protein. Literature on this pathogen reveals that it commonly causes otitis among dogs because of its location in the auditory meatus of canines. Also, it has strong association with pyoderma in dogs. The prime concern with this organism is the antibiotic resistance and relapse even after appropriate treatment. Very rarely, if any, cases have been reported about prostatic abscess (PA) with this microbe. Our patient had a history of recurrent UTIs and subsequent PA resulting in S. schleiferi bacteremia in contrast to gram negative bacteremia commonly associated with UTI. This organism was found to be resistant to methicillin, in spite of being negative for PBP2, which is a rare phenomenon and needs further studies. PMID:27092283

  18. 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.

  19. 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

  20. 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

  1. 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

  2. Antibacterial activity of oxyresveratrol against methicillin-resistant Staphylococcus aureus and its mechanism

    PubMed Central

    Joung, Dae-Ki; Mun, Su-Hyun; Choi, Sung-Hoon; Kang, Ok-Hwa; Kim, Sung-Bae; Lee, Young-Seob; Zhou, Tian; Kong, Ryong; Choi, Jang-Gi; Shin, Dong-Won; Kim, Youn-Chul; Lee, Dong-Sung; Kwon, Dong-Yeul

    2016-01-01

    Oxyresveratrol (ORV) is a naturally occurring compound found in mulberries that exhibits a wide spectrum of biological activities. However, the underlying mechanism of the action of ORV against the methicillin-resistant S. aureus (MRSA) pathogen has not yet been reported. MRSA is multidrug-resistant, causing skin and other types of infections. The aim of the present study was to examine the antimicrobial activity of ORV and the underlying mechanism of its action on MRSA. The antibacterial activity of ORV was evaluated using a minimum inhibitory concentration (MIC) assay, and the mechanism of its antibacterial action on S. aureus was investigated using a combination of ORV with detergent, ATPase inhibitors and peptidoglycan (PGN). In addition, the survival characteristics and changes in MRSA morphology were monitored using transmission electron microscopy (TEM). The MIC value of ORV against all S. aureus strains was found to be 125 µg/ml. The optical density at 600 nm of each suspension treated using a combination of ORV with Triton X-100, N,N'-dicyclohexylcarbodiimide or sodium azide was reduced by 68.9–89.8% compared with the value upon treatment with ORV alone. In the ORV and PGN combination assay, direct binding of ORV with PGN from S. aureus was evident. Furthermore, TEM examination of MRSA treated with ORV showed alterations in septa formation. In conclusion, these results showed that ORV has a strong antibacterial effect against S. aureus, mainly by increasing membrane permeability and inhibiting ATPase when combined with other drugs. PMID:27588079

  3. 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

  4. 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

  5. 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

  6. [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.

  7. 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.

  8. Staphylococcal cassette chromosome mec elements in methicillin-resistant coagulase-negative staphylococci from a Brazilian neonatal care unit.

    PubMed

    Salgueiro, Vivian Carolina; Azevedo, Milena Borgo; Iorio, Natalia Lopes Pontes; Amorim, Efigênia de Lourdes Teixeira; dos Santos, Kátia Regina Netto

    2014-10-01

    To characterize 46 methicillin-resistant coagulase-negative staphylococci from Brazilian neonates, we investigated their SCCmec type, susceptibility and clonality. Staphylococcus epidermidis and Staphylococcus haemolyticus were the prevalent species. SCCmec types III or IV were detected in 53.3% S. epidermidis, whereas 63.6% S. haemolyticus were nontypeable. Despite the diversity, specific clones carried specific SCCmec elements, highlighting that effective typing can help in epidemiological analysis.

  9. 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

  10. 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

  11. 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.

  12. 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

  13. Characterization of methicillin-resistant Staphylococcus pseudintermedius isolated from dogs and cats.

    PubMed

    Bardiau, Marjorie; Yamazaki, Kazuko; Ote, Isabelle; Misawa, Naoaki; Mainil, Jacques G

    2013-07-01

    The aim of this study was to explore the presence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in a collection of S. pseudintermedius strains isolated from dogs and cats with dermatitis in Japan and to compare their genotypic and phenotypic characteristics. Clonal relationships were determined by pulse field gel electrophoresis (PFGE), staphylococcal chromosomal cassette mec (SCCmec) typing, and multilocus sequence typing (MLST). Biofilm formation assay was performed using safranin staining in microplates. Three virulence genes coding for S. intermedius exfoliative toxin and Panton-Valentine leukocidin (siet, lukS-PV and lukF-PV) were searched for in a collection of strains. Antimicrobial resistance against 15 antibiotics was studied by a disc diffusion method. Twenty-seven MRSP were isolated. According to PFGE results the isolates were not closely related except for a few strains. MLST showed that the strains belonged to five groups, ST71 and ST26 being the two most prevalent. Three types of SCCmec (II, II-III and V) were identified. All isolates were siet-positive but PVL-negative. Most strains (except for two) produced strong biofilm in tryptic soy broth with glucose. Seventy-eight percent of the isolates were resistant or intermediate to twelve or more antibiotics. Our study demonstrates that the ST71 lineage is widespread in Japan and that ST26 could represent an emerging lineage. Moreover, most of our strains are capable of forming strong biofilm and possess siet gene, two virulence characteristics that probably help the bacteria to persist and spread. Finally, our MRSP strains show a strong resistance profile to antibiotics commonly used in veterinary medicine.

  14. Identification and characterization of methicillin-resistant Staphylococcus aureus (MRSA) from Austrian companion animals and horses.

    PubMed

    Loncaric, Igor; Künzel, Frank; Licka, Theresia; Simhofer, Hubert; Spergser, Joachim; Rosengarten, Renate

    2014-01-31

    The aim of this study was to investigate the antimicrobial resistance, resistance gene patterns and genetic relatedness of a collection of Austrian methicillin-resistant Staphylococcus aureus (MRSA) isolates from companion animals and horses. A total of 89 non-repetitive MRSA isolates collected during routine veterinary microbiological examinations from April 2004 to the end of 2012, and one isolate from 2013 were used for this study. The presence of mecA and other resistance genes was confirmed by PCR. Isolates were genotyped by spa typing, two multiple-locus variable-number tandem repeat analyses (MLVA) analyses, SCCmec typing and multilocus sequence typing (MLST). PCR targeting Panton-Valentine leukocidin (PVL) and detection of staphylococcal enterotoxins (SE), toxic shock syndrome toxin (TSST) was performed using PCR assays. Antimicrobial susceptibility testing was performed. Five sequence types (STs-ST398, ST254, ST22, ST5 and ST1), SCCmec types II, IVa, V, and non-type-abele, 8 spa-types (t003, t011, t036, t127, t386, t1348, and t4450), and two isolates could not be assigned, 21 MLVA-14Orsay types Multiplex-PCR MLVA (mMLVA) displayed 17 different MLVA types. The present study is the most comprehensive dealing with MRSA from Austrian companion animals and horses. The results confirm that MRSA ST398 is present in a wide range of animal species and is predominant especially in horses. In other companion animals it is unclear whether the infections with the different MRSA isolates investigated in the present study truly represents a rare phenomenon or may be an emerging problem in companion animals.

  15. 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

  16. Methicillin-Resistant Staphylococcus aureus from Brazilian Dairy Farms and Identification of Novel Sequence Types.

    PubMed

    Oliveira, C J B; Tiao, N; de Sousa, F G C; de Moura, J F P; Santos Filho, L; Gebreyes, W A

    2016-03-01

    The aim of this study was to investigate the phenotypic and genotypic diversity and anti-microbial resistance among staphylococci of dairy herds that originated from Paraiba State, north-eastern Brazil, a region where such studies are rare. Milk samples (n = 552) were collected from 15 dairy farms. Isolates were evaluated for anti-microbial susceptibility by Kirby-Bauer disc diffusion method. Confirmation of methicillin-resistant Staphylococcus aureus (MRSA) was performed using multiplex PCR targeting mecA and nuc genes in addition to phenotypic assay based on PBP-2a latex agglutination. Clonal relatedness of isolates was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) genotyping. Staphylococci were detected in 269 (49%) of the samples. Among these, 65 (24%) were S. aureus. The remaining 204 isolates were either coagulase-negative staphylococci (n = 188; 70%) or coagulase positive other than S. aureus (n = 16; 6%). Staphylococci were cultured in seven (35%) of the 20 hand swab samples, from which five isolates were S. aureus. The isolates were most commonly resistant against penicillin (43%), ampicillin (38%) and oxacillin (27%). The gene mecA was detected in 21 S. aureus from milk and in one isolate from a milker's hand. None of the isolates were resistant to vancomycin. PFGE findings showed high clonal diversity among the isolates. Based on MLST, we identified a total of 11 different sequence types (STs 1, 5, 6, 83, 97, 126, 1583, 1622, 1623, 1624 and 1625) with four novel STs (ST1622-ST1625). The findings show that MRSA is prevalent in milk from semi-extensive dairy cows in north-eastern Brazil, and further investigation on its extent in various types of milk production systems and the farm-to-table continuum is warranted.

  17. Identification of pyruvate kinase in methicillin-resistant Staphylococcus aureus as a novel antimicrobial drug target.

    PubMed

    Zoraghi, Roya; See, Raymond H; Axerio-Cilies, Peter; Kumar, Nag S; Gong, Huansheng; Moreau, Anne; Hsing, Michael; Kaur, Sukhbir; Swayze, Richard D; Worrall, Liam; Amandoron, Emily; Lian, Tian; Jackson, Linda; Jiang, Jihong; Thorson, Lisa; Labriere, Christophe; Foster, Leonard; Brunham, Robert C; McMaster, William R; Finlay, B Brett; Strynadka, Natalie C; Cherkasov, Artem; Young, Robert N; Reiner, Neil E

    2011-05-01

    Novel classes of antimicrobials are needed to address the challenge of multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA). Using the architecture of the MRSA interactome, we identified pyruvate kinase (PK) as a potential novel drug target based upon it being a highly connected, essential hub in the MRSA interactome. Structural modeling, including X-ray crystallography, revealed discrete features of PK in MRSA, which appeared suitable for the selective targeting of the bacterial enzyme. In silico library screening combined with functional enzymatic assays identified an acyl hydrazone-based compound (IS-130) as a potent MRSA PK inhibitor (50% inhibitory concentration [IC50] of 0.1 μM) with >1,000-fold selectivity over human PK isoforms. Medicinal chemistry around the IS-130 scaffold identified analogs that more potently and selectively inhibited MRSA PK enzymatic activity and S. aureus growth in vitro (MIC of 1 to 5 μg/ml). These novel anti-PK compounds were found to possess antistaphylococcal activity, including both MRSA and multidrug-resistant S. aureus (MDRSA) strains. These compounds also exhibited exceptional antibacterial activities against other Gram-positive genera, including enterococci and streptococci. PK lead compounds were found to be noncompetitive inhibitors and were bactericidal. In addition, mutants with significant increases in MICs were not isolated after 25 bacterial passages in culture, indicating that resistance may be slow to emerge. These findings validate the principles of network science as a powerful approach to identify novel antibacterial drug targets. They also provide a proof of principle, based upon PK in MRSA, for a research platform aimed at discovering and optimizing selective inhibitors of novel bacterial targets where human orthologs exist, as leads for anti-infective drug development.

  18. 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

  19. Antimicrobial susceptibility and molecular characteristics of methicillin-resistant Staphylococcus aureus in a Japanese secondary care facility.

    PubMed

    Kimura, Yumiko; Morinaga, Yoshitomo; Akamatsu, Norihiko; Matsuda, Junichi; Yamaryo, Takeshi; Kawakami, Kenji; Matsuo, Hidenori; Kosai, Kosuke; Uno, Naoki; Hasegawa, Hiroo; Yanagihara, Katsunori

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is prevalent in Japan, and the Staphylococcus cassette chromosome mec (SCCmec) type II is common among hospital-acquired MRSA isolates. Information pertaining to MRSA characteristics is limited, including SCCmec types, in primary or secondary care facilities. A total of 128 MRSA isolates (90 skin and soft tissue isolates and 38 blood isolates) were collected at a secondary care facility, Kawatana Medical Center, from 2005 to 2011. Antimicrobial susceptibility testing for anti-MRSA antibiotics and molecular testing for SCCmec and virulence genes (tst, sec, etb, lukS/F-PV) were performed. Strains positive for lukS/F-PV were analyzed by multilocus sequence typing and phage open-reading frame typing. SCCmec typing in skin and soft tissue isolates revealed that 65.6% had type IV, 22.2% had type II, 8.9% had type I, and 3.3% had type III. In blood isolates, 50.0% had type IV, 47.4% had type II, and 2.6% had type III. Minimum inhibitory concentrations, MIC(50)/MIC(90), against vancomycin, teicoplanin, linezolid, and arbekacin increased slightly in SCCmec II isolates from skin and soft tissue. MICs against daptomycin were similar between sites of isolation. SCCmec type II isolates possess tst and sec genes at a greater frequently than SCCmec type IV isolates. Four lukS/F-PV-positive isolates were divided into two clonal patterns and USA300 was not included. In conclusion, SCCmec type IV was dominant in blood, skin, and soft tissue isolates in a secondary care facility in Japan. Because antimicrobial susceptibility varies with the SCCmec type, SCCmec typing of clinical isolates should be monitored in primary or secondary care facilities.

  20. 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/ .

  1. Elderly infection in the community due to ST5/SCCmecII methicillin-resistant Staphylococcus aureus (the New York/Japan clone) in Japan: Panton-Valentine leukocidin-negative necrotizing pneumonia.

    PubMed

    Khokhlova, Olga; Tomita, Yusuke; Hung, Wei-Chun; Takano, Tomomi; Iwao, Yasuhisa; Higuchi, Wataru; Nishiyama, Akihito; Reva, Ivan; Yamamoto, Tatsuo

    2015-06-01

    An 89-year-old man suffered from and died of necrotizing pneumonia with rapid progression and cavity formation due to methicillin-resistant Staphylococcus aureus (MRSA). He was at no risk for hospital-acquired MRSA infection. His MRSA exhibited genotype ST5/spa2(t002)/agr2/SCCmecII/coagulaseII and was negative for Panton-Valentine leukocidin, indicating the New York/Japan clone (the predominant epidemic hospital-acquired MRSA clone in Japan). However, this strain expressed the cytolytic peptide (phenol-soluble modulin or δ-hemolysin) genes at high level, similar to USA300 (the most common community-acquired MRSA in the United States), indicating a variant of the New York/Japan clone with an important feature of community-acquired MRSA.

  2. Augmented HR Repair Mediates Acquired Temozolomide Resistance in Glioblastoma.

    PubMed

    Gil Del Alcazar, Carlos Rodrigo; Todorova, Pavlina Krasimirova; Habib, Amyn A; Mukherjee, Bipasha; Burma, Sandeep

    2016-10-01

    Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults and is universally fatal. The DNA alkylating agent temozolomide is part of the standard-of-care for GBM. However, these tumors eventually develop therapy-driven resistance and inevitably recur. While loss of mismatch repair (MMR) and re-expression of MGMT have been shown to underlie chemoresistance in a fraction of GBMs, resistance mechanisms operating in the remaining GBMs are not well understood. To better understand the molecular basis for therapy-driven temozolomide resistance, mice bearing orthotopic GBM xenografts were subjected to protracted temozolomide treatment, and cell lines were generated from the primary (untreated) and recurrent (temozolomide-treated) tumors. As expected, the cells derived from primary tumors were sensitive to temozolomide, whereas the cells from the recurrent tumors were significantly resistant to the drug. Importantly, the acquired resistance to temozolomide in the recurrent lines was not driven by re-expression of MGMT or loss of MMR but was due to accelerated repair of temozolomide-induced DNA double-strand breaks (DSB). Temozolomide induces DNA replication-associated DSBs that are primarily repaired by the homologous recombination (HR) pathway. Augmented HR appears to underpin temozolomide resistance in the recurrent lines, as these cells were cross-resistant to other agents that induced replication-associated DSBs, exhibited faster resolution of damage-induced Rad51 foci, and displayed higher levels of sister chromatid exchanges (SCE). Furthermore, in light of recent studies demonstrating that CDK1 and CDK2 promote HR, it was found that CDK1/2 inhibitors countered the heightened HR in recurrent tumors and sensitized these therapy-resistant tumor cells to temozolomide.

  3. Staphylococcal cassette chromosome mec typing and mecA sequencing in methicillin-resistant staphylococci from Algeria: a highly diversified element with new mutations in mecA.

    PubMed

    Djoudi, Ferhat; Bonura, Celestino; Touati, Abdelaziz; Aléo, Aurora; Benallaoua, Said; Mammina, Caterina

    2016-11-01

    Genetic mechanisms of methicillin resistance are still relevant in staphylococci. The aims of this study are to assess the possible exchanges of staphylococcal cassette chromosome mec (SCCmec) among isolates of methicillin-resistant staphylococci (MRS) and to check for known or new mutations in mecA DNA. A total of 35 MRS non-repetitive isolates were recovered, including 20 Staphylococcushaemolyticus, 7 Staphylococcusaureus, 4 Staphylococcussciuri, 2 Staphylococcussaprophyticus and 1 isolate each of Staphylococcusxylosus and Staphylococcuslentus. Only 16 of the 35 strains were assigned to known SCCmec types: 7 SCCmec VII, 6 SCCmec IV and 3 SCCmec III, with possible horizontal transfer of the SCCmec VII from methicillin-resistant S. haemolyticus to methicillin-susceptible S. aureus. mecA gene sequencing in ten selected isolates allowed description of nine punctual mutations, seven of which were reported for the first time. The most frequent mutation was G246E, identified in isolates of methicillin-resistant S. aureus, S. sciuri, S. saprophyticus and S. lentus. These results emphasized the high degree of genetic diversity of SCCmec element in MRS and describe new missense mutations in mecA, which might be important in understanding the evolution of methicillin and new β-lactam resistance.

  4. Clinical and epidemiological factors associated with methicillin resistance in community-onset invasive Staphylococcus aureus infections: prospective multicenter cross-sectional study in Korea.

    PubMed

    Kim, Eu Suk; Kim, Hong Bin; Kim, Gayeon; Kim, Kye-Hyung; Park, Kyung-Hwa; Lee, Shinwon; Choi, Young Hwa; Yi, Jongyoun; Kim, Chung Jong; Song, Kyoung-Ho; Choe, Pyoeng Gyun; Kim, Nam-Joong; Lee, Yeong-Seon; Oh, Myoung-Don

    2014-01-01

    Successful empirical therapy of Staphylococcus aureus infections requires the ability to predict methicillin resistance. Our aim was to identify predictors of methicillin resistance in community-onset (CO) invasive S. aureus infections. Sixteen hospitals across Korea participated in this study from May to December 2012. We prospectively included cases of S. aureus infection in which S. aureus was isolated from sterile clinical specimens ≤ 72 hours after hospitalization. Clinical and epidemiological data were gathered and compared in methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) cases. Community-associated (CA) infections were defined as in previous studies. In total, there were 786 cases of community-onset S. aureus infection, 102 (13.0%) of which were CA-MRSA. In addition to known risk factors, exposure to 3rd generation cephalosporins in the past 6 months [odds ratio (OR), 1.922; 95% confidence interval (CI), 1.176-3.142] and close contact with chronically ill patients in the past month (OR, 2.647; 95% CI, 1.189-5.891) were independent risk factors for MRSA infection. However, no clinical predictors of CA-MRSA were identified. Methicillin resistance, CO infection, and appropriateness of empirical antibiotics were not significantly related to 30-day mortality. MRSA infection should be suspected in patients recently exposed to 3rd generation cephalosporins or chronically-ill patients. There were no reliable predictors of CA-MRSA infection, and mortality was not affected by methicillin resistance.

  5. Cfr-mediated linezolid-resistance among methicillin-resistant coagulase-negative staphylococci from infections of humans.

    PubMed

    Cui, Lanqing; Wang, Yang; Li, Yun; He, Tao; Schwarz, Stefan; Ding, Yujing; Shen, Jianzhong; Lv, Yuan

    2013-01-01

    Four methicillin-resistant coagulase-negative staphylococci (MRCoNS), one Staphylococcus haemolyticus and three Staphylococcus cohnii, from infections of humans collected via the Ministry of Health National Antimicrobial Resistance Surveillance Net (Mohnarin) program in China were identified as linezolid-resistant. These four isolates were negative for the 23S rRNA mutations, but positive for the gene cfr. Mutations in the gene for the ribosomal protein L3, which resulted in the amino acid exchanges Gly152Asp and Tyr158Phe, were identified in S. haemolyticus 09D279 and S. cohnii NDM113, respectively. In each isolate, the cfr gene was located on a plasmid of ca. 35.4 kb, as shown by S1 nuclease pulsed-field gel electrophoresis and Southern blotting experiments. This plasmid was indistinguishable from the previously described plasmid pSS-02 by its size, restriction pattern, and a sequenced 14-kb cfr-carrying segment. Plasmid pSS-02 was originally identified in staphylococci isolated from pigs. This is the first time that a cfr-carrying plasmid has been detected in MRCoNS obtained from intensive care patients in China. Based on the similarities to the cfr-carrying plasmid pSS-02 from porcine coagulase-negative staphylococci, a transmission of this cfr-carrying plasmid between staphylococci from pigs and humans appears to be likely.

  6. Bacteria-Activated Theranostic Nanoprobes against Methicillin-Resistant Staphylococcus aureus Infection.

    PubMed

    Zhao, Zhiwei; Yan, Rong; Yi, Xuan; Li, Jingling; Rao, Jiaming; Guo, Zhengqing; Yang, Yanmei; Li, Weifeng; Li, Yong-Qiang; Chen, Chunying

    2017-03-30

    Despite numerous advanced imaging and sterilization techniques available nowadays, the sensitive in vivo diagnosis and complete elimination of drug-resistant bacterial infections remain big challenges. Here we report a strategy to design activatable theranostic nanoprobes against methicillin-resistant Staphylococcus aureus (MRSA) infections. This probe is based on silica nanoparticles coated with vancomycin-modified polyelectrolyte-cypate complexes (SiO2-Cy-Van), which is activated by an interesting phenomenon of bacteria-responsive dissociation of the polyelectrolyte from silica nanoparticles. Due to the aggregation of hydrophobic cypate fluorophores on silica nanoparticles to induce ground-state quenching, the SiO2-Cy-Van nanoprobes are nonfluorescent in aqueous environments. We demonstrate that MRSA can effectively pull out the vancomycin-modified polyelectrolyte-cypate complexes from silica nanoparticles and draw them onto their own surface, changing the state of cypate from off (aggregation) to on (disaggregation) and leading to in vitro MRSA-activated near-infrared fluorescence (NIRF) and photothermal elimination involving bacterial cell wall and membrane disruption. In vivo experiments show that this de novo-designed nanoprobe can selectively enable rapid (4 h postinjection) NIRF imaging with high sensitivity (10(5) colony-forming units) and efficient photothermal therapy (PTT) of MRSA infections in mice. Remarkably, the SiO2-Cy-Van nanoprobes can also afford a long-term tracking (16 days) of the development of MRSA infections, allowing real-time estimation of bacterial load in infected tissues and further providing a possible way to monitor the efficacy of antimicrobial treatment. The strategy of bacteria-activated polyelectrolyte dissociation from nanoparticles proposed in this work could also be used as a general method for the design and fabrication of bacteria-responsive functional nanomaterials that offer possibilities to combat drug-resistant

  7. 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

  8. Methicillin-resistant Staphylococcus aureus isolates in a hospital of Shanghai

    PubMed Central

    Wang, Xiaoguang; Ouyang, Lin; Luo, Lingfei; Liu, Jiqian; Song, Chiping; Li, Cuizhen; Yan, Hongjing; Wang, Ping

    2017-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) strains are now common both in the health care setting and in the community. Active surveillance is critical for MRSA control and prevention. Specimens of patients (200 patients with 1119 specimens) as well as medical staff and hospital setting (1000 specimens) were randomly sampled in a level 2 hospital in Shanghai from September 2011 to August 2012. Isolation, cultivation and identification of S. aureus were performed. Totally, 67 S. aureus strains were isolated. 32 S. aureus strains were isolated from patient samples; 13 (13/32, 40.6%) of the 32 S. aureus isolates were MRSA; sputum sample and patients in the department of general internal medicine were the most frequent specimen and patient group for S. aureus strains isolation. Remaining 35 S. aureus strains were isolated from the medical staff and hospital setting; 20 (20/35, 57.1%) of the 35 S. aureus isolates were MRSA; specimens sampled from doctors and nurses’ hands and nose and hospital facilities were the most frequent samples to isolate S. aureus. Resistant and virulent genes detection showed that, all 33 MRSA strains were mecA positive which accounts for 49.3% of the 67 S. aureus strains; 38 isolates were Panton-Valentine leukocidin (PVL) gene positive which accounts for 56.7% of the 67 S. aureus strains; and 17 (17/67, 25.4%) isolates are mecA and PVL genes dual positive. Multidrug-resistant strains of MRSA and PVL positive S. aureus are common in patients, medical staff and hospital setting, the potential health threat is worthy of our attention. PMID:28030828

  9. Methicillin-resistant staphylococcus aureus isolates in a hospital of shanghai.

    PubMed

    Wang, Xiaoguang; Ouyang, Lin; Luo, Lingfei; Liu, Jiqian; Song, Chiping; Li, Cuizhen; Yan, Hongjing; Wang, Ping

    2017-01-24

    Methicillin-resistant Staphylococcus aureus (MRSA) strains are now common both in the health care setting and in the community. Active surveillance is critical for MRSA control and prevention. Specimens of patients (200 patients with 1119 specimens) as well as medical staff and hospital setting (1000 specimens) were randomly sampled in a level 2 hospital in Shanghai from September 2011 to August 2012. Isolation, cultivation and identification of S. aureus were performed. Totally, 67 S. aureus strains were isolated. 32 S. aureus strains were isolated from patient samples; 13 (13/32, 40.6%) of the 32 S. aureus isolates were MRSA; sputum sample and patients in the department of general internal medicine were the most frequent specimen and patient group for S. aureus strains isolation. Remaining 35 S. aureus strains were isolated from the medical staff and hospital setting; 20 (20/35, 57.1%) of the 35 S. aureus isolates were MRSA; specimens sampled from doctors and nurses' hands and nose and hospital facilities were the most frequent samples to isolate S. aureus. Resistant and virulent genes detection showed that, all 33 MRSA strains were mecA positive which accounts for 49.3% of the 67 S. aureus strains; 38 isolates were Panton-Valentine leukocidin (PVL) gene positive which accounts for 56.7% of the 67 S. aureus strains; and 17 (17/67, 25.4%) isolates are mecA and PVL genes dual positive. Multidrug-resistant strains of MRSA and PVL positive S. aureus are common in patients, medical staff and hospital setting, the potential health threat is worthy of our attention.

  10. Clinical inquiries. When should you suspect community-acquired MRSA? How should you treat it?

    PubMed

    May, Todd J; Safranek, Sarah

    2009-05-01

    There are no clinical or epidemiologic features that will help you to clearly distinguish community-acquired methicillin-resistant Staphylococcus aureus infections (CA-MRSA) from methicillin-sensitive (CA-MSSA) infections. Incision and drainage is the primary therapy for purulent skin and soft tissue infections. There are inadequate data evaluating the role of oral antibiotics for MRSA.

  11. Clonal Complexes and Diversity of Exotoxin Gene Profiles in Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Isolates from Patients in a Spanish Hospital▿

    PubMed Central

    Argudín, M. A.; Mendoza, M. C.; Méndez, F. J.; Martín, M. C.; Guerra, B.; Rodicio, M. R.

    2009-01-01

    Molecular epidemiology studies have allowed the identification of the methicillin (meticillin)-resistant (MRSA) and methicillin-susceptible (MSSA) clonal complexes (CCs) and clones of Staphylococcus aureus circulating in a Spanish hospital recently. Of 81 isolates tested, 32.1% were MRSA. Most of them carried staphylococcal cassette chromosome mec (SCCmec) IVc (88.5%) and belonged to CC5 (88.5%; multilocus sequence typing types ST125 [mainly associated with spa type t067], ST5, and ST228). A higher diversity was found among MSSA isolates (67.9%). Eighty percent shared the genetic background of major MRSA lineages (CC5 [38.2%; ST125 and ST5], CC30 [25.5%; ST30], CC45 [14.5%; ST45 and ST47], and CC8 [1.8%; ST8]), but CC12, CC15, CC51, and CC59 were also detected. Many exotoxin genes were present in each of the 81 isolates, independent of whether they were involved in sepsis (11 to 22) or other types of infections (13 to 21), and they appeared in 73 combinations. The relevant data are that (i) all isolates were positive for hemolysin and leukotoxin genes (98.8% for lukED and 25.9% for lukPV); (ii) all contained an enterotoxin gene cluster (egc with or without seu), frequently with one or more genes encoding classical enterotoxins; (iii) about half were positive for tst and 95% were positive for exfoliatin-encoding genes (eta, etb, and/or etd); and (iv) the four agr groups were detected, with agrII (55.6%) and agrIII (23.5%) being the most frequent. Taken together, results of the present study suggest a frequent acquisition and/or loss of exotoxin genes, which may be mediated by efficient intralineage transfer of mobile genetic elements and exotoxin genes therein and by eventual breakage of interlineage barriers. PMID:19458176

  12. Rifampicin-fosfomycin coating for cementless endoprostheses: antimicrobial effects against methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Alt, Volker; Kirchhof, Kristin; Seim, Florian; Hrubesch, Isabelle; Lips, Katrin S; Mannel, Henrich; Domann, Eugen; Schnettler, Reinhard

    2014-10-01

    New strategies to decrease infection rates in cementless arthroplasty are needed, especially in the context of the growing incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections. The purpose of this study was to investigate the antimicrobial activity of a rifampicin-fosfomycin coating against methicillin-sensitive Staphylococcus aureus (MSSA) and MRSA in a rabbit infection prophylaxis model. Uncoated or rifampicin-fosfomycin-coated K-wires were inserted into the intramedullary canal of the tibia in rabbits and contaminated with an inoculation dose of 10(5) or 10(6) colony-forming units of MSSA EDCC 5055 in study 1 and MRSA T6625930 in study 2, respectively. After 28days the animals were killed and clinical, histological and microbiological assessment, including pulse-field gel electrophoresis, was conducted. Positive culture growth in agar plate testing and/or clinical signs and/or histological signs were defined positive for infection. Statistical evaluation was performed using Fisher's exact test. Both studies showed a statistically significant reduction of infection rates for rifampicin-fosfomycin-coated implants compared to uncoated K-wires (P=0.015). In both studies none of the 12 animals that were treated with a rifampicin-fosfomycin-coated implant showed clinical signs of infection or a positive agar plate testing result. In both studies, one animal of the coating group showed the presence of sporadic bacteria with concomitant inflammatory signs in histology. The control groups in both studies exhibited an infection rate of 100% with clear clinical signs of infection and positive culture growth in all animals. In summary, the rifampicin-fosfomycin-coating showed excellent antimicrobial activity against both MSSA and MRSA, and therefore warrants further clinical testing.

  13. Broad-spectrum acquired resistance in barley induced by the Pseudomonas pathosystem shares transcriptional components with Arabidopsis systemic acquired resistance.

    PubMed

    Colebrook, E H; Creissen, G; McGrann, G R D; Dreos, R; Lamb, C; Boyd, L A

    2012-05-01

    Inducible resistance responses play a central role in the defense of plants against pathogen attack. Acquired resistance (AR) is induced alongside defense toward primary attack, providing broad-spectrum protection against subsequent pathogen challenge. The localization and molecular basis of AR in cereals is poorly understood, in contrast with the well-characterized systemic acquired resistance (SAR) response in Arabidopsis. Here, we use Pseudomonas syringae as a biological inducer of AR in barley, providing a clear frame of reference to the Arabidopsis-P. syringae pathosystem. Inoculation of barley leaf tissue with the nonadapted P. syringae pv. tomato avrRpm1 (PstavrRpm1) induced an active local defense response. Furthermore, inoculation of barley with PstavrRpm1 resulted in the induction of broad-spectrum AR at a distance from the local lesion, "adjacent" AR, effective against compatible isolates of P. syringae and Magnaporthe oryzae. Global transcriptional profiling of this adjacent AR revealed similarities with the transcriptional profile of SAR in Arabidopsis, as well as transcripts previously associated with chemically induced AR in cereals, suggesting that AR in barley and SAR in Arabidopsis may be mediated by analogous pathways.

  14. Isolation, Virulence, and Antimicrobial Resistance of Methicillin-Resistant Staphylococcus aureus (MRSA) and Methicillin Sensitive Staphylococcus aureus (MSSA) Strains from Oklahoma Retail Poultry Meats.

    PubMed

    Abdalrahman, Lubna S; Stanley, Adriana; Wells, Harrington; Fakhr, Mohamed K

    2015-05-29

    Staphylococcus aureus is one the top five pathogens causing domestically acquired foodborne illness in the U.S. Only a few studies are available related to the prevalence of S. aureus and MRSA in the U.S. retail poultry industry. The objectives of this study were to determine the prevalence of S. aureus (MSSA and MRSA) in retail chicken and turkey meats sold in Tulsa, Oklahoma and to characterize the recovered strains for their antimicrobial resistance and possession of toxin genes. A total of 167 (114 chicken and 53 turkey) retail poultry samples were used in this study. The chicken samples included 61 organic samples while the rest of the poultry samples were conventional. The overall prevalence of S. aureus was 57/106 (53.8%) in the conventional poultry samples and 25/61 (41%) in the organic ones. Prevalence in the turkey samples (64.2%) was higher than in the chicken ones (42.1%). Prevalence of S. aureus did not vary much between conventional (43.4%) and organic chicken samples (41%). Two chicken samples 2/114 (1.8%) were positive for MRSA. PFGE identified the two MRSA isolates as belonging to PFGE type USA300 (from conventional chicken) and USA 500 (from organic chicken) which are community acquired CA-MRSA suggesting a human based source of contamination. MLST and spa typing also supported this conclusion. A total of 168 Staphylococcus aureus isolates (101 chicken isolates and 67 turkey isolates) were screened for their antimicrobial susceptibility against 16 antimicrobials and their possession of 18 different toxin genes. Multidrug resistance was higher in the turkey isolates compared to the chicken ones and the percentage of resistance to most of the antimicrobials tested was also higher among the turkey isolates. The hemolysin hla and hld genes, enterotoxins seg and sei, and leucocidins lukE-lukD were more prevalent in the chicken isolates. The PVL gene lukS-lukF was detected only in chicken isolates including the MRSA ones. In conclusion, S. aureus is

  15. 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.

  16. Evaluation of commercial selective agars in screening for methicillin-resistant Staphylococcus aureus.

    PubMed

    Yang, Hee-Young; Suh, Jin-Tae; Lee, Hee-Joo

    2010-01-01

    To evaluate methicillin-resistant S. aureus (MRSA) detection methods, we compared (a) mannitol salt agar with cefoxitin (MSA-FX), (b) MRSASelect agar (Bio-Rad), (c) MRSA ID (bioMerieuex), and (d) CHROMagar MRSA (BD Diagnostics) as selective media for culturing nasal swab specimens collected from intensive care unit (ICU) patients and healthcare personnel. A total of 99 (17.1%) cases of MRSA were recovered from 578 specimens. Four (5.5%) cases were identified from healthcare personnel and 95 (18.8%) were from ICU patients. The sensitivity of MSA-FX, MRSASelect, MRSA ID, and CHROMagar MRSA was 83.8, 87.9, 80.8, and 84.8% after 18 hr; 92.9, 94.9, 90.9, and 91.9% after 24 hr; and 96.0, 100, 99.0, and 99.0% after 48 hr, respectively. The specificity of MSA-FX, MRSASelect, MRSA ID, and CHROMagar MRSA was 97.7, 99.0, 98.7. and 99.8% after 18 hr; 97.1, 98.5, 98.1, and 99.5% after 24 hr; and 95.2, 97.7, 97.9, and 99.0% after 48 hr, respectively. In conclusion, all four media showed good results after the 24 hr readings, but MRSA ID and CHROMagar MRSA media required readings at 48 hr due to increased sensitivity at this time point.

  17. 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.

  18. [Antibiotics for treatment of infections by methicillin-resistant Staphylococcus aureus (MRSA)].

    PubMed

    Stahlmann, R

    2014-10-01

    Over the last 50 years methicillin-resistant S. aureus (MRSA) spread globally. Vancomycin is still the most recommended antibiotic for MRSA-infections. Teicoplanin is an alternative glycopeptide with longer elimination half-life. Telavancin is a more recently developed derivative of vancomycin with similar clinical efficacy as vancomycin. It is not recommended for treatment of patients with renal insufficiency. Nephrotoxicity limits the therapeutic use of glycopeptide antibiotics. The oxazolidinone linezolid exhibits similar to superior therapeutic efficacy. Hematologic controls are necessary during treatment with this antibacterial agent. Neurotoxic effects have been observed mainly in patients who received prolonged linezolid treatment. Attention must be paid to possible interactions with concomitantly given drugs acting on the serotonergic system. New therapeutic options arise with ceftaroline, the first β-lactam antibiotic with activity against MRSA. However, controlled clinical trials with pulmonary MRSA infections have not been conducted with ceftaroline. Daptomycin, a lipopeptide, and tigecycline, a glycylcyclin are active in vitro against MRSA as well, but are also not indicated in pulmonary MRSA infections. These antibiotics show in an exemplary manner that antibacterial activity in vitro is an important prerequisite, but relevant data for a therapeutic decision should be derived from randomized controlled clinical double-blind trials.

  19. 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.

  20. 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

  1. 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

  2. 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

  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. 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

  5. An Unusual Occurrence of Methicillin Resistant Staphylococcal Endocarditis with Vancomycin Creep Phenomenon – A Therapeutic Challenge

    PubMed Central

    Sneha, S; Venishetty, Shanthan; Seshadri, Shubha; Mukhopadhyay, Chiranjay

    2016-01-01

    Infective endocarditis by Methicillin Resistant Staphylococcus aureus (MRSA) bacteraemia is a common association and carries a high mortality. However, rising Minimum Inhibitory Concentrations (MICs) for vancomycin amongst MRSA strains is an emerging threat which carries poor prognosis and higher mortality. Here, we report a case of 41-year-old young non-addict gentleman presenting with fever of 3 days duration following recovery from an acute kidney injury necessitating haemodialysis. Systemic examination revealed signs of mitral regurgitation and left sided cerebellar signs. Laboratory investigations revealed anaemia, MRSA bacteraemia and transthoracic echocardiogram showed a mitral valve vegetation. He was diagnosed with MRSA mitral valve endocarditis with acute left cerebellar infarct. He was initially treated with intravenous vancomycin based on MIC at the dose of one gram every twelfth hourly. As the MRSA strain was shown to demonstrate a vancomycin creep phenomemon along with worsening clinical condition of the patient, treatment was changed to intravenous daptomycin at dose of 9mg/kg as per blood culture and sensitivity pattern which was administered for 6 weeks. Following initiation of daptomycin patient became afebrile and vegetations reduced in size and finally disappeared. PMID:28208915

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  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. 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.

  1. 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

  2. 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.

  3. 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

  4. Characterization of methicillin-resistant coagulase-negative staphylococci (MRCoNS) in retail meat.

    PubMed

    Bhargava, Kanika; Zhang, Yifan

    2014-09-01

    This study was to understand the extent of methicillin-resistant coagulase-negative staphylococci (MRCoNS) serving as a mecA reservoir in retail meat. MRCoNS were isolated from retail meat (beef, chicken, and turkey) in Detroit and characterized by sodA gene sequencing for species identification, staphylococcal cassette chromosome mec (SCCmec) typing, and pulsed-field gel electrophoresis (PFGE). Unique MRCoNS isolates recovered from 25 meat samples were comprised of Staphylococcus sciuri (n = 13), Staphylococcus fleuretti (n = 4), Staphylococcus lentus (n = 3), Staphylococcus epidermidis (n = 2), Staphylococcus vitulinus (n = 1), Staphylococcus saprophyticus (n = 1) and Staphylococcus pasteuri (n = 1). Heterogeneous and composite SCCmec types, including I, III, IV, V, I + V and III + V were identified in 16 isolates. Same SCCmec types were recovered in different staphylococcal species and meat sources. Indistinguishable PFGE patterns were also observed in S. sciuri isolated from beef, chicken, and turkey, and with different SCCmec types. In conclusion, multiple CoNS species can serve as reservoirs for mecA. In addition to the clonal transmission of MRCoNS in meat, horizontal occurrence of SCCmec is observed in staphylococcal species.

  5. 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

  6. 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.

  7. 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.

  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. 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

  11. Cellular memory of acquired stress resistance in Saccharomyces cerevisiae.

    PubMed

    Guan, Qiaoning; Haroon, Suraiya; Bravo, Diego González; Will, Jessica L; Gasch, Audrey P

    2012-10-01

    Cellular memory of past experiences has been observed in several organisms and across a variety of experiences, including bacteria "remembering" prior nutritional status and amoeba "learning" to anticipate future environmental conditions. Here, we show that Saccharomyces cerevisiae maintains a multifaceted memory of prior stress exposure. We previously demonstrated that yeast cells exposed to a mild dose of salt acquire subsequent tolerance to severe doses of H(2)O(2). We set out to characterize the retention of acquired tolerance and in the process uncovered two distinct aspects of cellular memory. First, we found that H(2)O(2) resistance persisted for four to five generations after cells were removed from the prior salt treatment and was transmitted to daughter cells that never directly experienced the pretreatment. Maintenance of this memory did not require nascent protein synthesis after the initial salt pretreatment, but rather required long-lived cytosolic catalase Ctt1p that was synthesized during salt exposure and then distributed to daughter cells during subsequent cell divisions. In addition to and separable from the memory of H(2)O(2) resistance, these cells also displayed a faster gene-expression response to subsequent stress at >1000 genes, representing transcriptional memory. The faster gene-expression response requires the nuclear pore component Nup42p and serves an important function by facilitating faster reacquisition of H(2)O(2) tolerance after a second cycle of salt exposure. Memory of prior stress exposure likely provides a significant advantage to microbial populations living in ever-changing environments.

  12. Antibacterial activities of macrolactin A and 7-O-succinyl macrolactin A from Bacillus polyfermenticus KJS-2 against vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus.

    PubMed

    Kim, Dong Hee; Kim, Hye Kyung; Kim, Kang Min; Kim, Chun Kyu; Jeong, Min Ho; Ko, Chan Young; Moon, Kyung Ho; Kang, Jae Seon

    2011-01-01

    The principal objective of this study was to evaluate the antibacterial activities of macrolactin A (MA) and 7-O-succinyl macrolactin A (SMA) generated from Bacillus polyfermenticus KJS-2 against vancomycin-resistant enterococci (VREs) and methicillin-resistant Staphylococcus aureus. The minimal inhibitory concentrations (MICs) of MA and SMA against VREs were 16 and 2∼1 μg/mL, respectively, and the MICs of MA and SMA against methicillin-resistant Staphylococcus aureus were 2 and < 0.25 μg/mL, respectively. Their MIC values were comparable or superior to those of teicoplanin. In evaluating the inhibitory effects of intestinal VRE colonization in mice, the oral MA and SMA effected a rapid inhibition of intestinal VRE colonization in mice, and the intraperitoneal SMA also inhibited VRE colonization, whereas intraperitoneal MA did not.

  13. Annotation of the Staphylococcus aureus Metabolome Using Liquid Chromatography Coupled to High-Resolution Mass Spectrometry and Application to the Study of Methicillin Resistance.

    PubMed

    Aros-Calt, Sandrine; Muller, Bruno H; Boudah, Samia; Ducruix, Céline; Gervasi, Gaspard; Junot, Christophe; Fenaille, François

    2015-11-06

    Staphylococcus aureus can cause a variety of severe disease patterns and can readily acquire antibiotic resistance; however, the mechanisms by which this commensal becomes a pathogen or develops antibiotic resistance are still poorly understood. Here we asked whether metabolomics can be used to distinguish bacterial strains with different antibiotic susceptibilities. Thus, an efficient and robust method was first thoroughly implemented to measure the intracellular metabolites of S. aureus in an unbiased and reproducible manner. We also placed special emphasis on metabolome coverage and annotation and used both hydrophilic interaction liquid chromatography and pentafluorophenyl-propyl columns coupled to high-resolution mass spectrometry in conjunction with our spectral database developed in-house to identify with high confidence as many meaningful S. aureus metabolites as possible. Overall, we were able to characterize up to 210 metabolites in S. aureus, which represents a substantial ∼50% improvement over previously published data. We then preliminarily compared the metabolic profiles of 10 clinically relevant methicillin-resistant and susceptible strains harvested at different time points during the exponential growth phase (without any antibiotic exposure). Interestingly, the resulting data revealed a distinct behavior of "slow-growing" resistant strains, which show modified levels of several precursors of peptidoglycan and capsular polysaccharide biosynthesis.

  14. Eradication of Methicillin-Resistant Staphylococcus aureus and of Enterobacteriaceae Expressing Extended-Spectrum Beta-Lactamases on a Model Pig Farm

    PubMed Central

    Kellner, Sophia Ricarda; Schulze-Geisthoevel, Sophia Veronika; Hack, Sylvia; Engelhart, Steffen; Bodenstein, Isabel; Al-Sabti, Nahed; Reif, Marion; Fimmers, Rolf; Körber-Irrgang, Barbara; Harlizius, Jürgen; Hoerauf, Achim; Exner, Martin; Bierbaum, Gabriele; Petersen, Brigitte

    2015-01-01

    Colonization of livestock with bacteria resistant to antibiotics is considered a risk for the entry of drug-resistant pathogens into the food chain. For this reason, there is a need for novel concepts to address the eradication of drug-resistant commensals on farms. In the present report, we evaluated the decontamination measures taken on a farm contaminated with methicillin-resistant Staphylococcus aureus (MRSA) and Enterobacteriaceae expressing extended-spectrum β-lactamases (ESBL-E). The decontamination process preceded the conversion from piglet breeding to gilt production. Microbiological surveillance showed that the decontamination measures eliminated the MRSA and ESBL-E strains that were detected on the farm before the complete removal of pigs, cleaning and disinfection of the stable, and construction of an additional stable meeting high-quality standards. After pig production was restarted, ESBL-E remained undetectable over 12 months, but MRSA was recovered from pigs and the environment within the first 2 days. However, spa (Staphylococcus aureus protein A gene) typing revealed acquisition of an MRSA strain (type t034) that had not been detected before decontamination. Interestingly, we observed that a farmworker who had been colonized with the prior MRSA strain (t2011) acquired the new strain (t034) after 2 months. In summary, this report demonstrates that decontamination protocols similar to those used here can lead to successful elimination of contaminating MRSA and ESBL-E in pigs and the stable environment. Nevertheless, decontamination protocols do not prevent the acquisition of new MRSA strains. PMID:26341200

  15. The Allosteric Site for the Nascent Cell Wall in Penicillin-Binding Protein 2a: An Achilles' Heel of Methicillin-Resistant Staphylococcus aureus.

    PubMed

    Acebrón, Iván; Chang, Mayland; Mobashery, Shahriar; Hermoso, Juan A

    2015-01-01

    The ability to resist the effect of a wide range of antibiotics makes methicillin-resistant Staphylococcus aureus (MRSA) a leading global human pathogen. A key determinant of resistance to β-lactam antibiotics in this organism is penicillin-binding protein 2a (PBP2a), an enzyme that catalyzes the crosslinking reaction between two adjacent peptide stems during the peptidoglycan biosynthesis. The recently published crystal structure of the complex of PBP2a with ceftaroline, a cephalosporin antibiotic that shows efficacy against MRSA, has revealed the allosteric site at 60-Å distance from the transpeptidase domain. Binding of ceftaroline to the allosteric site of PBP2a triggers conformational changes that lead to the opening of the active site from a closed conformation, where a second molecule of ceftaroline binds to give inhibition of the enzyme. The discovery of allostery in MRSA remains the only known example of such regulation of cellwall biosynthesis and represents a new paradigm in fighting MRSA. This review summarizes the present knowledge of the allosteric mechanism, the conformational changes allowing PBP2a catalysis and the means by which some clinical strains have acquired resistance to ceftaroline by disrupting the allosteric mechanism.

  16. Short communication: Prevalence of methicillin resistance in coagulase-negative staphylococci and Staphylococcus aureus isolated from bulk milk on organic and conventional dairy farms in the United States.

    PubMed

    Cicconi-Hogan, K M; Belomestnykh, N; Gamroth, M; Ruegg, P L; Tikofsky, L; Schukken, Y H

    2014-05-01

    The objective of this study was to evaluate the presence of methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus spp. in bulk tank milk samples from 288 organic and conventional dairy farms located in New York, Wisconsin, and Oregon from March 2009 to May 2011. Due to recent publications reporting the presence mecC (a mecA homolog not detected by traditional mecA-based PCR methods), a combination of genotypic and phenotypic approaches was used to enhance the recovery of methicillin-resistant organisms from bulk tank milk. In total, 13 isolates were identified as methicillin resistant: Staph. aureus (n=1), Staphylococcus sciuri (n=5), Staphylococcus chromogenes (n=2), Staphylococcus saprophyticus (n=3), Staphylococcus agnetis (n=1), and Macrococcus caseolyticus (n=1). The single methicillin-resistant Staph. aureus isolate was identified from an organic farm in New York, for an observed 0.3% prevalence at the farm level. The methicillin-resistant coagulase-negative staphylococci prevalence was 2% in the organic population and 5% in the conventional population. We did not identify mecC in any of the isolates from our population. Of interest was the relatively high number of methicillin-resistant Staph. sciuri recovered, as the number of isolates from our study was considerably higher than those recovered from other recent studies that also assessed milk samples. Our research suggests that the presence of a potential methicillin-resistant Staphylococcus reservoir in milk, and likely the dairy farm population in the United States, is independent of the organic or conventional production system.

  17. Characterization of methicillin-resistant Staphylococcus aureus isolates from fitness centers in the Memphis metropolitan area, Tennessee.

    PubMed

    Mukherjee, Nabanita; Sulaiman, Irshad M; Banerjee, Pratik

    2016-12-01

    Indoor skin-contact surfaces of public fitness centers may serve as reservoirs of potential human transmission of methicillin-resistant Staphylococcus aureus (MRSA). We found a high prevalence of multidrug-resistant (MDR) MRSA of clonal complex 59 lineage harboring a variety of extracellular toxin genes from surface swab samples collected from inanimate surfaces of fitness centers in the Memphis metropolitan area, Tennessee. Our findings underscore the role of inanimate surfaces as potential sources of transmission of MDR MRSA strains with considerable genetic diversity.

  18. Detection of methicillin-resistant staphylococci by biosensor assay consisting of nanoscale films on optical fiber long-period gratings.

    PubMed

    Bandara, Aloka B; Zuo, Ziwei; Ramachandran, Siddharth; Ritter, Alfred; Heflin, James R; Inzana, Thomas J

    2015-08-15

    Methicillin-resistance among Staphylococcus species is a major health problem in hospitals, communities, and animals. There is a need for culture-free diagnostic assays that can be carried out rapidly, and maintain a high degree of sensitivity and specificity. To address this need an ionic self-assembled multilayer (ISAM) film was deposited on the surface of a long-period grating (LPG) optical fiber by immersion alternately in poly-allylamine hydrochloride and in poly-1-[p-(3'-carboxy-4'-hydroxyphenylazo) benzenesulfonamido]-1,2-ethandiyl (PCBS), resulting in terminal carboxyl groups on the LPG-ISAM. The terminal carboxyl groups were covalently conjugated to monoclonal antibodies (MAb) specific to penicillin-binding-protein 2a of methicillin resistant (MR) staphylococci. After exposure of the LPG-ISAM to 10(2) colony forming units (CFU)/ml of MR S. aureus (MRSA) for 50 min., light transmission was reduced by 19.7%. In contrast, after exposure to 10(6) CFU/ml of methicillin-sensitive S. aureus (MSSA) attenuation of light transmission was less than 1.8%. Exposure of the LPG-ISAM to extracts of liver, lungs, or spleen from mice infected with MRSA attenuated light transmission by 11.7-73.5%. In contrast, exposure of the biosensor to extracts from MSSA-infected mice resulted in 5.6% or less attenuation of light transmission. When the sensor was tested with 36 strains of MR staphylococci, 15 strains of methicillin-sensitive staphylococci, 10 strains of heterologous genera (all at 10(4) CFU/ml), or tissue samples from mice infected with MRSA, there was complete agreement between MR and non-MR bacteria determined by antibiotic susceptibility testing and the biosensor assay when the cutoff value for attenuation of light transmission was 6.3%. Thus, the biosensor described has the potential to detect MR staphylococci in clinical samples with a high degree of sensitivity and specificity.

  19. Rapid detection of methicillin-resistant Staphylococcus aureus in pork using a nucleic acid-based lateral flow immunoassay.

    PubMed

    Zhang, Hongwei; Ma, Luyao; Ma, Lina; Hua, Marti Z; Wang, Shuo; Lu, Xiaonan

    2017-02-21

    Methicillin-resistant Staphylococcus aureus (MRSA) is considered as one of the leading causes of food poisonings worldwide. Due to the high prevalence and extensive challenges in clinical treatment, a rapid and accurate detection method is required to differentiate MRSA from other S. aureus isolated from foods. Since the methicillin resistance of S. aureus is due to the acquisition of the mecA gene from staphylococcal chromosome cassette, the presence of the mecA gene is interpreted as a marker for the identification of MRSA. In this study, a low-cost lateral flow immunoassay (LFI) strip was used to detect the mecA amplicons subsequent to polymerase chain reaction (PCR). The specificity of this PCR-LFI assay was tested between MRSA and methicillin-susceptive S. aureus. Both the test line and control line were shown up on the LFI strip for MRSA, whereas only the control line developed for methicillin-susceptive S. aureus. The detection limit of PCR-LFI assay was 20fg for genomic DNA (100 times more sensitive than gel electrophoresis) and 2×10(0)CFU per 100g