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

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.

Hsueh PR ，Lee SY ，Perng CL ，Chang TY ，Lu JJ ... -  《-》

Clinical isolates of Staphylococcus aureus from the Arkhangelsk region, Russia: antimicrobial susceptibility, molecular epidemiology, and distribution of Panton-Valentine leukocidin genes.

Vorobieva V ，Bazhukova T ，Hanssen AM ，Caugant DA ，Semenova N ，Haldorsen BC ，Simonsen GS ，Sundsfjord A ... -  《-》

Molecular epidemiology and clinical characteristics of hetero-resistant vancomycin intermediate Staphylococcus aureus bacteremia in a Taiwan Medical Center.

Hetero-resistant vancomycin intermediate Staphylococcus aureus (hVISA) emerges worldwide in recent decade. The purpose of this study was to investigate the glycopeptide usage trend, the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) with reduced vancomycin susceptibility, the susceptible rates to newer antimicrobials, molecular epidemiology, clinical characteristics, as well as patient outcome among S. aureus bacteremia cases in a Taiwanese medical center. From March to December 2009, among 118 S. aureus blood isolates in a Taiwanese medical center, 62 MRSA isolates were screened for hVISA by Etest macromethod and further confirmed with modified population analysis profiling method. Molecular typing of hVISA isolates was performed. Five (4.2%) isolates were hVISA. Compared with non-hVISA MRSA, hVISA isolates had higher resistant rates to ciprofloxacin, gentamicin, trimethoprim/sulfamethoxazole, and tetracycline. Among the MRSA infected, patients infected with hVISA had a higher in-hospital mortality rate than non-hVISA group (60% vs. 17.5%, p = 0.025). All hVISA isolates were nosocomial and had different pulsed field gel electrophoresis pulsotype. Four hVISA isolates carried type III staphylococcal cassette chromosome mec (SCCmec) and the remaining isolate carried SCCmec type II. Three of the 5 hVISA isolates belonged to sequence type 239, which is the most common type in Taiwan. Glycopeptide usage increased in the study hospital; however, these hVISA-infected patients did not receive glycopeptide treatment in the recent 6 months. Our results suggested hVISA might have disseminated in the hospital before we observed this highest hVISA rate in Taiwan and increasing glycopeptide usage might serve as selection pressure. Measures to prevent the transmission of MRSA with reduced vancomycin susceptibility and to treat such infection were urgently needed.

Lin SY ，Chen TC ，Chen FJ ，Chen YH ，Lin YI ，Siu LK ，Lu PL ... -  《-》

Nationwide surveillance study of vancomycin intermediate Staphylococcus aureus strains in Korean hospitals from 2001 to 2006.

Chung G ，Cha J ，Han S ，Jang H ，Lee K ，Yoo J ，Yoo J ，Kim H ，Eun S ，Kim B ，Park O ，Lee Ys ... -  《JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY》

Polyclonal emergence and importation of community-acquired methicillin-resistant Staphylococcus aureus strains harbouring Panton-Valentine leucocidin genes in Belgium.

Denis O ，Deplano A ，De Beenhouwer H ，Hallin M ，Huysmans G ，Garrino MG ，Glupczynski Y ，Malaviolle X ，Vergison A ，Struelens MJ ... -  《JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY》