Persistent strains of coagulase-negative staphylococci in a neonatal intensive care unit: virulence factors and invasiveness
| Autor: | J. Zorman, Michael Otto, Arild Rønnestad, A.S. Anderson, Trond Flægstad, J. U. Ericson Sollid, A. Villaruz, Tore G. Abrahamsen, Claus Klingenberg |
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| Rok vydání: | 2007 |
| Předmět: |
Coagulase
Microbiology (medical) Staphylococcus Bacterial Toxins virulence factors Virulence Microbiology Antibiotic resistance Vancomycin Staphylococcus epidermidis Intensive Care Units Neonatal Drug Resistance Bacterial Pulsed-field gel electrophoresis Humans Antibacterial agent Cross Infection biology endemic clones Infant Newborn typing Coagulase-negative staphylococci invasive capacity General Medicine Staphylococcal Infections biology.organism_classification neonates Electrophoresis Gel Pulsed-Field Infectious Diseases Biofilms Multilocus sequence typing Staphylococcus haemolyticus Infant Premature |
| Zdroj: | Clinical Microbiology and Infection. 13(11):1100-1111 |
| ISSN: | 1198-743X |
| DOI: | 10.1111/j.1469-0691.2007.01818.x |
| Popis: | Coagulase-negative staphylococci (CoNS) are the major cause of nosocomial bacteraemia in neonates. The aim of this study was to investigate whether persistent strains of CoNS possess specific bacterial characteristics as compared with sporadic non-cluster isolates. In total, 180 blood culture isolates (95 contaminants and 85 invasive isolates) obtained from a single neonatal unit over a 12-year period were studied. Pulsed-field gel electrophoresis (PFGE) identified 87 persistent CoNS strains (endemic clones). The two largest PFGE clusters belonged to a single clonal complex according to multilocus sequence typing. Patients colonised or infected with endemic clones were of lower gestational age than those infected with non-cluster strains. One Staphylococcus haemolyticus cluster appeared to selectively colonise and infect the most extreme pre-term infants. Endemic clones were characterised by high levels of antibiotic resistance and biofilm formation. All 51 isolates belonging to the two largest PFGE clusters were ica operon-positive. Genes encoding Staphylococcus epidermidis surface protein B and the production of phenol-soluble modulins (PSMs) were also more prevalent among endemic clones than among non-cluster strains. However, endemic clones were not more prevalent among invasive isolates than among contaminants. These findings indicate that multiple selective factors, including antibiotic resistance, biofilm formation, surface proteins with adhesive properties, and PSMs regulated by agr, increase the ability of CoNS to persist in a hospital environment. It may be more prudent, when searching for new therapeutic targets, to focus on ubiquitous components of CoNS instead of putative virulence factors that do not clearly contribute to increased invasive capacity. |
| Databáze: | OpenAIRE |
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