Staphylococcus aureus nosocomial infections: the role of a rapid and low-cost characterization for the establishment of a surveillance system

New Microbiol. 2010 Jul;33(3):223-32.

Abstract

Continuous surveillance on resistance patterns and characterization of Staphylococcus aureus represent simple and low-cost techniques to understand and evaluate the effectiveness of infection control and antimicrobial prescribing measures. In this study we analyzed the antibiotic susceptibility and trends for S. aureus strains collected from bacteraemia cases in a five year period. Between 2004 and 2008 we noted a progressive decrease in the number of S. aureus isolates compared to all pathogens from clinical specimens and S. aureus bloodstream infections (BSI) reflected a similar trend. In particular we analyzed 185 isolates from blood cultures: 89 isolates were MSSA and 96 isolates were MRSA. Molecular SCCmec typing of these strains showed an absolute prevalence of types I and II, whereas five spa types from 96 isolates were obtained. Resistance pattern analysis allowed us to place MRSA strains into 12 antibiotypes and the major antibiotype was resistant to penicillin, gentamicin, erythromycin, clindamycin and ciprofloxacin. The predominant antibiotype among the MSSA isolates was resistant only to penicillin. In addition, 19.1% of MSSA are susceptible to all antibiotics tested. We also found a close association between antibiotyping 1 and genotyping t002/SCCmecI of MRSA strains, suggesting a nosocomial scenario dominated by a few particular clones.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Bacterial Typing Techniques
  • Cross Infection / microbiology*
  • Drug Resistance, Multiple, Bacterial
  • Infection Control / economics
  • Infection Control / methods*
  • Methicillin-Resistant Staphylococcus aureus / classification
  • Methicillin-Resistant Staphylococcus aureus / drug effects
  • Methicillin-Resistant Staphylococcus aureus / genetics
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Microbial Sensitivity Tests / economics
  • Microbial Sensitivity Tests / methods*
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / classification
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / isolation & purification*

Substances

  • Anti-Bacterial Agents