Tuesday, December 18, 2012

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.