α-Hemolysin Activity of Methicillin-Susceptible Staphylococcus aureus Predicts Ventilator-associated Pneumonia
| Autor: | Stefan Malafa, Agnes Sonnevend, Harald Rouha, Eszter Nagy, Donald E. Craven, Jana Hudcova, Bence Z. Henics, Lukas Stulik |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Male
Methicillin-Resistant Staphylococcus aureus Pulmonary and Respiratory Medicine Staphylococcus aureus Virulence Factors Bacterial Toxins Virulence Critical Care and Intensive Care Medicine medicine.disease_cause Microbiology Cohort Studies Hemolysin Proteins Mice Risk Factors Genotype medicine Animals Humans Typing Bronchitis Aged Aged 80 and over business.industry Ventilator-associated pneumonia Pneumonia Ventilator-Associated Middle Aged Staphylococcal Infections respiratory system bacterial infections and mycoses medicine.disease Hemolysis respiratory tract diseases Disease Models Animal Pneumonia Immunology Female business Methicillin Susceptible Staphylococcus Aureus |
| Zdroj: | American Journal of Respiratory and Critical Care Medicine. 190:1139-1148 |
| ISSN: | 1535-4970 1073-449X |
| DOI: | 10.1164/rccm.201406-1012oc |
| Popis: | Colonization of lower airways by Staphylococcus aureus is a risk factor for the development of ventilator-associated tracheobronchitis (VAT) and ventilator-associated pneumonia (VAP). However, little is known about the virulence factors of methicillin-sensitive and -resistant S. aureus (MSSA and MRSA) that may influence host colonization and progression to VAT and VAP.We evaluated MRSA and MSSA endotracheal aspirates (ETA) for genotype and α-hemolysin activity in relation to the development of VAT and VAP.Serial S. aureus ETA isolates from ventilated patients were analyzed for methicillin resistance, molecular type by Multi-Locus Sequence Typing and spa-typing, and α-hemolysin activity by semiquantitative analysis of hemolysis on sheep blood agar and quantitative measurement of cytolysis of human lung epithelial cells. The virulence of selected strains was assessed in mice by intranasal challenge.We detected S. aureus from ETA samples in a quarter of the 231 ventilated patients analyzed; one-third of them developed VAP. VAP patients (n = 15) were mainly infected by MSSA strains (87%), whereas colonized individuals (n = 18) not progressing to disease mainly carried MRSA strains (68%). MSSA isolates from colonized or VAT patients exhibited significantly lower α-hemolysin activity than those from VAP cases; however, no such relationship was found with MRSA strains. α-Hemolysin activity of S. aureus isolates was predictive for virulence in mouse pneumonia model.MSSA strains with strong blood agar hemolysis and high α-hemolysin activity are markers for VAP, but not VAT, and might be considered in differential diagnosis and initiation of therapy. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|