Friday, December 28, 2012

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

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]


Dept. of Surgery, Sakai City Hospital.


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.

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

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]


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


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.

Sunday, December 23, 2012

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

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

Dec 2012


Division of Infectious Diseases.


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
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.

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

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

Dec 2012


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


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.

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.

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

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

Dec 2012


Pontchaillou Univ. Hosp., Rennes, France.


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:

Tuesday, December 18, 2012

Leg MRSA images

Continuous high-dose vancomycin combination therapy for methicillin-resistant staphylococcal prosthetic hip infection: a prospective cohort study.

Continuous high-dose vancomycin combination therapy for methicillin-resistant staphylococcal prosthetic hip infection: a prospective cohort study.

OCt 2012


Service de Médecine Interne et Rhumatologie, Paris, France.


Few data are available on treatment and outcome of methicillin-resistant (MR) staphylococcal prosthetic joint infections. Vancomycin remains the treatment of choice for these infections, but its efficacy and safety in bone-and-joint infections are insufficiently documented. We conducted a prospective cohort study on 60 patients treated between November 2002 and December 2008 for chronic MR staphylococcal (44 S. epidermidis, nine other coagulase-negative Staphylococcus and seven S. aureus) prosthetic hip infections (PHIs). Twenty-two patients had previously undergone surgery for their PHI and 21 had previously received antibiotics. All patients had surgery (exchange arthroplasty for 58 patients, resection arthroplasty for two) and received an antibiotic regimen combining high-dose continuous intravenous vancomycin infusion (target serum concentration 30-40 mg/L) with another antibiotic for 6 weeks, followed by an additional 6 weeks of oral intake. Two years after surgery, infection was considered cured in 41 (68%) patients and only two relapses occurred after one-stage exchange arthroplasty. Nineteen (32%) patients experienced nephrotoxicity that was generally mild (RIFLE class R for 14 patients, class I for four patients and class F for one patient) and most often reversible. Continuous high-dose intravenous vancomycin combination therapy is an effective, feasible and reasonably safe treatment of chronic MR staphylococcal PHI.

Methicillin resistance is not a predictor of severity in community-acquired Staphylococcus aureus necrotizing pneumonia-results of a prospective observational study.

Methicillin resistance is not a predictor of severity in community-acquired Staphylococcus aureus necrotizing pneumonia-results of a prospective observational study.

Sept 2012


 National Reference Centre for Staphylococci INSERM U851, Faculté de Médecine Lyon Est, Université de Lyon, Lyon  Biometry and Evolutionary Biology Laboratory, UMR 5558, CNRS, Université de Lyon, Lyon  Hygiene and Epidemiology Unit, Hospital Edouard Herriot, Hospices Civils de Lyon, Lyon  Division of Infectious Disease, Hospital Pitié Salpêtrière, Paris  Division of Paediatric Intensive Care, Hospital Femme Mère Enfant, Hospices Civils de Lyon, Bron, France.


Clin Microbiol Infect 


Staphylococcal necrotizing pneumonia (NP) is a severe disease associated with Panton-Valentine leucocidin (PVL). NP was initially described for methicillin-susceptible Staphylococcus aureus (MSSA) infection, but cases associated with methicillin-resistant S. aureus (MRSA) infection have increased concomitantly with the incidence of community-acquired MRSA worldwide. The role of methicillin resistance in the severity of NP remains controversial. The characteristics and outcomes of 133 patients with PVL-positive S. aureus community-acquired pneumonia (CAP) were compared according to methicillin resistance. Data from patients hospitalized for PVL-positive S. aureus CAP in France from 1986 to 2010 were reported to the National Reference Centre for Staphylococci and were included in the study. The primary end point was mortality. Multivariate logistic modelling and the Cox regression were used for subsequent analyses. We analysed 29 cases of PVL-MRSA and 104 cases of PVL-MSSA pneumonia. Airway haemorrhages were more frequently associated with PVL-MSSA pneumonia. However, no differences in the initial severity or the management were found between these two types of pneumonia. The rate of lethality was 39% regardless of methicillin resistance. By Cox regression analysis, methicillin resistance was not found to be a significant independent predictor of mortality at 7 or 30 days (p 0.65 and p 0.71, respectively). Our study demonstrates that methicillin resistance is not associated with the severity of staphylococcal necrotizing pneumonia.