Draft Genome Sequence of the Methicillin-Resistant Staphylococcus aureus Isolate MRSA-M2.

2013

Harro JM, Daugherty S, Bruno VM, Jabra-Rizk MA, Rasko DA, Shirtliff ME.

Source

Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland, USA.

Abstract

We report the draft genome sequence of a methicillin-resistant strain of Staphylococcus aureus, designated MRSA-M2. This clinical isolate was obtained from an osteomyelitis patient undergoing treatment at the University of Texas Medical Branch (Galveston, TX). This strain is an ST30, spa type T019, agr III strain and has been utilized as a model S. aureus strain in a number of proteomic, transcriptomic, and animal model studies.

PubMed

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

Feb 2013

Vitko NP, Richardson AR.

Source

Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina.

Abstract

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. Curr. Protoc. Microbiol.

Full Text

Wiley Online

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

Jan 2013

Jackson CR, Davis JA, Barrett JB.

Source

Bacterial Epidemiology and Antimicrobial Resistance Research Unit, USDA-ARS, Russell Research Center, Athens, GA 30605.

Abstract

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 same geographic area using broth microdilution antimicrobial susceptibility testing, Multilocus sequence typing (MLST), spa typing, SCCmec typing, and Pulsed-Field Gel Electrophoresis (PFGE). S. aureus was isolated from 45% (45/100) of pork products and 63% (63/100) of beef products; mecA was detected in S. aureus from both pork (3/100; 3%) and beef (4/100; 4%). Fifty percent (50/100) of human S. aureus also contained mecA. Multidrug resistance was detected among MRSA from all sources. All MRSA (n=57) were SCCmec type IV and nine different spa types were present among the isolates (t002, t008, t012, t024, t179, t337, t548, t681, and t1062). Four sequence types (ST5, ST8, ST9, and ST30) were detected using MLST; the majority of MRSA were ST8 followed by ST5. One retail beef MRSA was ST8, while the remaining three were ST5. In retail pork MRSA, ST5, ST9, and ST30 were observed. The majority of human MRSA were ST8. Thirty-seven MRSA isolates were pvl+, one of which was a retail beefMRSA. Using PFGE, MLST, and spa typing, three retail beef MRSA were identical in PFGE pattern, ST, and spa type to two human clonal MRSA (USA100 and USA300). One additional retail beef MRSA had a similar PFGE pattern to a human MRSAisolate, whereas none of the retail pork MRSA had similar PFGE patterns to human MRSA. This data suggests that the retail beef samples were contaminated from a human source possibly during processing of the meat and may present a source ofMRSA to consumers and others who handle raw meat.

Methicillin-resistant Staphylococcus aureus - induced thrombo-inflammatory response is reduced with timely antibiotic administration.

Jan 2013

Franks Z, Campbell RA, Vieira de Abreu A, Holloway JT, Marvin JE, Kraemer BF, Zimmerman GA, Weyrich AS, Rondina MT.

Source

Matthew T. Rondina, MD, University of Utah, Department of Internal Medicine, 50 North Medical Drive, Room 4B120, SLC, Utah 84132, USA, Tel.: +1 801 581 7818, Fax: +1 801 585 1393, E-mail: matthew.rondina@hsc.utah.edu.

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA ) induces a pro-thrombotic and pro-inflammatory milieu. Although timely antibiotic administration in MRSA sepsis may improve outcomes by arresting bacterial growth, the effects of antibiotics on mitigating injurious thrombo-inflammatory cellular responses remains unexplored. Using a newly developed human whole blood model and an in vivo mouse model of MRSA infection, we examined how antibiotics inhibit MRSA induced thrombo-inflammatory pathways. Human whole blood was inoculated with MRSA. Thrombin generation and inflammatory cytokine synthesis was measured in the presence or absence of linezolid and vancomycin. C57BL/6 mice were injected with MRSAand the effect of vancomycin administration was examined. MRSA accelerated thrombin generation in a time- and concentration-dependent manner and induced the release of cytokines, including interleukin (IL)-6, IL-8, and monocyte chemotactic protein (MCP)-1. The increase in thrombin generation and inflammatory responses was mediated through the synthesis of tissue factor and cytokines, respectively, and the release of microparticles. The early administration of antibiotics restored normal thrombin generation patterns and significantly reduced the synthesis of cytokines. In contrast, when antibiotic administration was delayed, thrombin generation and cytokine synthesis were not significantly reduced. In mice infected with MRSA, early antibiotic administration reduced thrombin anti-thrombin complexes and cytokine synthesis, whereas delayed antibiotic administration did not. These data provide novel mechanistic evidence of the importance of prompt antibiotic administration in infectious syndromes.

Schattauer

Pharmacoeconomic analysis of the treatment of methicillin-resistant Staphylococcus aureus with daptomycin or vancomycin

Pharmacoeconomic analysis of the treatment of methicillin-resistant Staphylococcus aureus with daptomycin or vancomycin

Dec 2012

[Article in Spanish]

Rubio-Terrés C, Rubio-Rodríguez D, Majos N, Grau S.

Source

Carlos Rubio Terrés, Health value, C/ Virgen de Aránzazu, 21. 5ºB, 28034, Madrid, Spain. crubioterres@healthvalue.org.

Abstract

Introduction. 

The increased morbidity, mortality and high costs associated with bacteremia caused by methicillin-resistant Staphylococcus aureus (MRSA) is a major public health problem. Pharmacoeconomic analysis was performed to compare the efficiency of daptomycin (DAP) against vancomycin (VAN) in the treatment of this infection. 

Methods. 

Retrospective, deterministic and probabilistic cost-effectiveness analysis. The effectiveness of the treatments was estimated from the results of a randomized clinical trial, which compared DAP (6 mg / kg IV daily) and VAN (1 g IV every 12 hours), both with or without gentamicin (1 mg / kg IV every 8 hours). Resource utilization was estimated from the clinical trial of the drug datasheets and Spanish sources, the unit costs were obtained also from Spanish sources. Monte Carlo probabilistic analysis and deterministic analysis were performed. 

Results. 

The clinical trial cure rates were higher with DAP (44.4%, 95% CI 43.5 to 45.4%) than with VAN (31.8%, 95% CI 30.9 to 32.7%) not statistically significant (p = 0.2203) but with economic impact. With DAP would occur less costs due to treatment failure (rescue antibiotics, additional tests, prolonged hospital stay and adverse reactions) than with VAN. In the base case the average cost of disease per patient was € 12,329 to € 12,696 with DAP and VAN (difference of 367 €). DAP treatment was dominant (more effective, with lower costs than VAN) both in the deterministic and probabilistic analysis. In the Monte Carlo simulation, DAP was the most cost-effective treatment in 100% of the 10,000 simulations, for a willingness to pay € 12,000 per additional cure (approximate cost of MRSA bacteraemia episode). 

Conclusions. 

According to this model, daptomycin is more cost-effective than vancomycin in treating MRSA bacteremia. The higher cost of acquisition of daptomycin does not imply a higher cost of treating this infection.

PubMed

A case of refractory deep incisional surgical site infection due to methicillin-resistant Staphylococcus aureus(MRSA) and successfully treated with oral linezolid.

Nov 2012

[Article in Japanese]

Matsumoto H, Kawabata R, Kishimoto T, Yamamoto E, Kimura Y, Imamura H, Yamamoto T, Takemoto H, Fukunaga M,Ohzato H.

Source

Dept. of Surgery, Sakai City Hospital.

Abstract

We report a case of methicillin-resistant Staphylococcus aureus(MRSA) surgical site infection successfully treated with linezolid. A 66-year-old man had undergone total gastrectomy for gastric cancer after neoadjuvant chemotherapy. Three days after the operation, he was diagnosed with deep incisional surgical site infection due to MRSA, and wound care was started. After discharge, he received adjuvant chemotherapy and wound care, but the wound had not healed in 10 months. We started treatment with oral linezolid and nutritional support, and the wound was fully healed 12 months after the operation. Antibiotic treatment with oral linezolid may be effective for refractory deep incisional surgical site infection due to MRSA in outpatients.

PierOnline

Incidence and seasonal distribution of methicillin-resistant Staphylococcus aureus in adult outpatients at a clinic in Buenos Aires province: period 2006 to 2011

Oct 2012

[Article in Spanish]

Verón MT, Ojeda MG, Avino F, Spelzzini A, Barboza AL, Petrozzino Y.

Source

Servicio de Infectología y Microbiología Clínica, Clínica Privada Independencia. Luis María Drago 5681 (1605) Munro, Provincia de Buenos Aires, Argentina. E-mail: mtveron@gmail.com.

Abstract

In the last decade there was a significant growth of community-acquired methicillin-resistant Staphylococcus aureus(ca-MrSa). We herein describe the annual incidence, seasonal distribution, antimicrobial resistance and phenotypes of MrSain adult outpatients. From january 2006 to december 2011, 173 strains of S. aureus were studied, 77 (45 %) of which wereMrSa. The annual incidence per 100 processed materials increased from 0.13 in 2006 to 0.62 in 2011 due to the oxacillin-resistant phenotype, showing peaks in springsummer until december 2008 and subsequent peaks in autumn-winter. The antimicrobial resistance profile was: erythromycin 24 (31 %), clindamycin 22 (29 %), gentamicin 23 (30 %), ciprofloxacin 13 (17 %), trimethoprim-sulfamethoxazole 3 (4 %), chloramphenicol 2 (3 %), rifampicin 2 (3 %), and minocycline 0. Sixteen phenotypes were identified; the oxacillin-resistant phenotype being the most common, accounting for 53 % (41 isolates) and exhibiting an increase ranging from 31 % to 65 %. The empirical treatment of infections was changed and prevention measures were implemented among contacts.

PubMed

Long-Term Risk for Readmission, Methicillin-resistant Staphylococcus aureus (MRSA) Infection, and Death among MRSA-Colonized Veterans.

Dec 2012

Quezada Joaquin NM, Diekema DJ, Perencevich EN, Bailey G, Winokur PL, Schweizer ML.

Source

Division of Infectious Diseases.

Abstract

Background: 

While numerous studies assessed outcomes of MRSA colonization over the short term, little is known about longer-term outcomes after discharge. An assessment of long-term outcomes could inform the utility of various MRSA prevention approaches.Methods: A matched cohort study was performed among Veterans Affairs (VA) patients screened for MRSA colonization between the years 2007 and 2009 and followed to evaluate outcomes until 2010. Cox proportional hazard models were used to evaluate the association between MRSA colonization and long-term outcomes such as infection-related readmission, and crude mortality.Results: 404 veterans were included, 206 of whom were MRSA carriers and 198 who were non-carriers. There were no culture-proven MRSA infections on readmission among the non-carriers, but 13% of MRSA-carriers were readmitted with culture proven MRSA infections on readmission  MRSA carriers were significantly more likely to be readmitted, be readmitted more than once due to proven or probable MRSA infections, and be readmitted within 90 days of discharge compared to non-carriers. Infection-related readmission (adjusted hazard ratio [AHR] =4.07; 95% confidence interval [CI]: 2.16, 7.67) and mortality (AHR=2.71; 95% CI: 1.87, 3.91) were significantly higher amongMRSA carriers compared to non-carriers, after statistically adjusting for potential confounders

Conclusions: 

Among a cohort of VA patients, MRSA carriers are at high risk of infection-related readmission, MRSA infection and mortality compared to non-carriers. Non- carriers are at very low risk of subsequent MRSA infection. Future studies should address whether interventions such as nasal or skin decolonization could result in improved outcomes for MRSA carriers.

Antimicrobial Agents and Chemotherapy

A Trial of Discontinuation of Empiric Vancomycin Therapy in Patients with Suspected Methicillin-Resistant Staphylococcus aureus Healthcare-Associated Pneumonia.

Dec 2012

Boyce JM, Pop OF, Abreu-Lanfranco O, Hung WY, Fisher A, Karjoo A, Thompson B, Protopapas Z.

Source

Hospital Epidemiology and Infection Control Program, Yale-New Haven Hospital, New Haven, CT.

Abstract

Background:

Healthcare-associated pneumonia (HCAP) guidelines recommend de-escalating initial antibiotic therapy based on results of lower respiratory tract cultures. In the absence of adequate lower respiratory cultures, physicians are sometimes reluctant to discontinue empiric vancomycin given for suspected methicillin-resistant Staphylococcus aureus (MRSA) HCAP. We evaluated a strategy of discontinuing vancomycin if both nasal and throat cultures were negative for MRSA when lower respiratory cultures were not available.Methods:An antimicrobial stewardship team identified patients receiving empiric vancomycin for suspected or proven HCAP, but for whom adequate lower respiratory cultures were not available. Nasal and throat swab specimens were obtained and plated on MRSA selective media. If both nasal and throat MRSA cultures were negative, the stewardship team recommended discontinuation of empiric vancomycin. Demographic and clinical aspects, a clinical pulmonary infection score (CPIS) on the day of the stewardship recommendation, and mortality of patients for whom vancomycin was discontinued were obtained by retrospective chart review.Results:A convenience sample of 91 patients with nasal and throat cultures negative for MRSA in the absence of adequate respiratory cultures had empiric vancomycin therapy discontinued. A retrospective review revealed that 88 (97%) of patients had a CPIS ≤ 6 on the day of the stewardship recommendation. In-hospital mortality (7.7%) was similar to a previous study of de-escalation of antibiotics in pneumonia patients without adequate cultures.

Conclusion:

In the absence of adequate lower respiratory cultures, it is reasonable to discontinue empiric vancomycin HCAP therapy in patients with negative MRSA nasal and throat cultures and CPIS.

 Antimicrobial Agents and Chemotherapy

Comparison of six Generic Vancomycin Products for the Treatment of Methicillin-Resistant Staphylococcus aureus, Experimental Endocarditis in Rabbits.

Dec 2012

Tattevin P, Saleh-Mghir A, Davido B, Ghout I, Massias L, Garcia de la Maria C, Miró JM, Perronne C, Laurent F, Crémieux AC.

Source

Pontchaillou Univ. Hosp., Rennes, France.

Abstract

Concerns have recently emerged about the potency and the quality of generic vancomycin (VAN) products approved for use in humans, based on experiments in a neutropenic mouse thigh infection model. However, other animal models may be more appropriate to decipher VAN generics bactericidal activity in vivo, and to predict their efficacy in humans. We aimed to compare the bactericidal activity of six generic VAN products currently used in France (Mylan, Sandoz), Spain (Hospira), Switzerland (Teva), and United States (Akorn-Strides, and APP), in a rabbit model of aortic valve endocarditis induced by 8 × 10(7) CFU of methicillin-resistant S. aureus (MRSA) COL strain (VAN MIC, 1.5 μg/ml). In vitro, there were no significant differences in the time-kill curve studies performed with the six generic VAN products. Ten rabbits in each group were treated with i.v. VAN, 60 mg/kg b.i.d., during 4 days. Mean peak serum VAN levels, measured 45 mn after the last injection, ranged from 35.5 (APP) to 45.9 μg/ml (Teva). Mean trough serum VAN levels, measured 12 h after the last injection, ranged from 2.3 (Hospira) to 9.2 μg/ml (APP). All generic VAN products were superior to controls (no treatment) in terms of residual organisms in vegetations (P < 0.02 for each comparison), and in spleen (P < 0.005 for each comparison). Pairwise comparisons of generic VAN products found no significant differences. In conclusion, a stringent MRSA endocarditis model found no significant differences in the bactericidal activity of six generic VAN products currently used in Europe and America

Full text:

Antimicrobial Agents and Chemotherapy

Methicillin-Resistant Staphylococcus aureus: A Food-Borne Pathogen?

Nov 2012

Wendlandt S, Schwarz S, Silley P.

Source

Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, 31535 Newstadt-Matieusee, Germany; email: sarah.wendlandt@fli.bund.de.

Abstract

Prior to the 1990s, most methicillin-resistant Staphylococcus aureus (MRSA) was hospital-associated (HA-MRSA); community-associated MRSA (CA-MRSA) then began to cause infections outside the health-care environment. The third significant emergence of MRSA has been in livestock animals [livestock-associated MRSA (LA-MRSA)]. The widespread and rapid growth in CA-MRSA and LA-MRSA has raised the question as to whether MRSA is indeed a food-borne pathogen. The observations on animal-to-animal and animal-to-human transfer of LA-MRSA have prompted research examining the origin of LA-MRSA and its capacity to cause zoonotic disease in humans. This review summarizes the current knowledge aboutMRSA from foodproducing animals and foods with respect to the role of these organisms to act as food-borne pathogens and considers the available tools to track the spread of these organisms. It is clear thatLA-MRSAandCA-MRSAand even HA-MRSA can be present in/on food intended for human consumption, but we conclude on the basis of the published literature that this does not equate to MRSA being considered a food-borne pathogen. Expected final online publication date for the Annual Review of Food Science and Technology Volume 4 is February 28, 2013. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.

PubMed

Complete Genome Sequence of Wide-Host-Range Staphylococcus aureus Phage JD007.

Dec 2012

Cui Z, Song Z, Wang Y, Zeng L, Shen W, Wang Z, Li Q, He P, Qin J, Guo X.

Source

Department of Medical Microbiology and Parasitology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.

Abstract

Methicillin-resistant Staphylococcus aureus-related infections have become a serious problem worldwide. Bacteriophage therapy is an alternative approach against this threat. S. aureus phage JD007, which belongs to the Myoviridae family according to transmission electron microscopic imaging, could lyse nearly 30% of the S. aureus strains from Ruijin Hospital, Shanghai, China, and was isolated from chicken feces in Shanghai, China. The complete genome showed that JD007 is a linear, double-stranded DNA phage 141,836 bp in length with a GC content of 30.4% encoding 217 open reading frames. A BLAST search of the JD007 genome revealed that it was very similar to that of phage GH15.

PubMed

Riccardin C derivatives as anti-MRSA agents: Structure-activity relationship of a series of hydroxylated bis(bibenzyl)s.

Oct 2012

Sawada H, Okazaki M, Morita D, Kuroda T, Matsuno K, Hashimoto Y, Miyachi H.

Source

Division of Pharmaceutical Sciences, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan.

Abstract

Members of a series of macrocyclic bis(bibenzyl) riccardin-class derivatives were found to exhibit antibacterial activity towards methicillin-resistant Staphylococcus aureus (anti-MRSA activity). Structure-activity relationship (SAR) studies were conducted, focusing on the number and position of the hydroxyl groups. The minimum essential structure for anti-MRSAactivity was also investigated.

Elsevier

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

Nov 2012

Goldstein RE, Micallef SA, Gibbs SG, Davis JA, He X, George A, Kleinfelter LM, Schreiber NA, Mukherjee S, Sapkota A,Joseph SW, Sapkota AR.

Source

Maryland Institute for Applied Environmental Health, University of Maryland School of Public Health, College Park, Maryland, USA.

Abstract

Background: The incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections is increasing in the United States, and it is possible that municipal wastewater could be a reservoir of this microorganism. To date, no U.S. studies have evaluated the occurrence of MRSA in wastewater.

Objective: We examined the occurrence ofMRSA and methicillin-susceptible S. aureus (MSSA) at U.S. wastewater treatment plants.

Methods: We collected wastewater samples from two Mid-Atlantic and two Midwest wastewater treatment plants between October 2009 and October 2010. 

Samples were analyzed for MRSA and MSSA using membrane filtration. Isolates were confirmed using biochemical tests and PCR (polymerase chain reaction). Antimicrobial susceptibility testing was performed by Sensititre® microbroth dilution. Staphylococcal cassette chromosome mec (SCCmec) typing, Panton-Valentine leucocidin (PVL) screening, and pulsed field gel electrophoresis (PFGE) were performed to further characterize the strains.

Data were analyzed by two-sample proportion tests and analysis of variance.

Results: We detected MRSA (n = 240) and MSSA (n = 119) in 22 of 44 (50%) and 24 of 44 (55%) wastewater samples, respectively. The odds of samples being MRSA-positive decreased as treatment progressed: 10 of 12 (83%) influent samples were MRSA-positive, while only one of 12 (8%) effluent samples was MRSA-positive. Ninety-three percent and 29% of unique MRSA and MSSA isolates, respectively, were multidrug resistant. SCCmec types II and IV, the pvl gene, and USA types 100, 300, and 700 (PFGE strain types commonly found in the United States) were identified among the MRSA isolates.

Conclusions: Our findings raise potential public health concerns for wastewater treatment plant workers and individuals exposed to reclaimed wastewater. Because of increasing use of reclaimed wastewater, further study is needed to evaluate the risk of exposure to antibiotic-resistant bacteria in treated wastewater.

PubMed