Clonal dissemination of meticillin-resistant and vancomycin-intermediate Staphylococcus aureus in a Taiwanese hospital

Int J Antimicrob Agents. 2010 Oct;36(4):307-12. doi: 10.1016/j.ijantimicag.2010.06.035. Epub 2010 Aug 3.

Abstract

Meticillin-resistant and vancomycin-intermediate Staphylococcus aureus (VISA) has emerged worldwide. However, clonal dissemination of VISA in hospitals has rarely been reported. We investigated 43 isolates of meticillin-resistant VISA [vancomycin minimum inhibitory concentrations (MICs) of 4 microg/mL in 35 isolates and 8 microg/mL in 8 isolates) recovered from 21 hospitalised patients. A glycopeptide was given prior to isolation of VISA in 14 of the patients. Five patients (23.8%) died despite vancomycin therapy. All isolates were inhibited by tigecycline at 0.5 microg/mL, linezolid at 1 microg/mL and ceftobiprole at 2 microg/mL. Five isolates (11.6%) had reduced susceptibility to daptomycin (MICs of 1-2 microg/mL). In addition, 6 of the 43 VISA isolates had decreased susceptibility to autolysis by 0.05% Triton X-100. All 43 VISA isolates carried staphylococcal chromosome cassette mec (SCCmec) type III and accessory gene regulator (agr) group I but none carried the Panton-Valentine leukocidin gene (lukS-lukF). None of the enterococcal van genes were detected in the 43 VISA isolates. Molecular typing generated by pulsed-field gel electrophoresis revealed that all isolates belonged to one pulsotype, indicating clonal dissemination of VISA isolates in the hospital. The high rate of non-susceptibility to daptomycin amongst these VISA isolates is alarming and indicates the limitation of this agent for the treatment of infections due to VISA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / pharmacology
  • Female
  • Hospitals, University*
  • Humans
  • Male
  • Methicillin / pharmacology
  • Methicillin Resistance / genetics*
  • Methicillin-Resistant Staphylococcus aureus / drug effects
  • Methicillin-Resistant Staphylococcus aureus / genetics*
  • Microbial Sensitivity Tests
  • Middle Aged
  • Molecular Epidemiology
  • Staphylococcal Infections / epidemiology
  • Staphylococcal Infections / microbiology
  • Staphylococcal Infections / transmission*
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / genetics*
  • Taiwan / epidemiology
  • Vancomycin / pharmacology
  • Vancomycin Resistance / genetics*
  • Young Adult

Substances

  • Anti-Bacterial Agents
  • Vancomycin
  • Methicillin