台湾一家医学中心耐异质性万古霉素中介金黄色葡萄球菌菌血症的分子流行病学和临床特征。
Molecular epidemiology and clinical characteristics of hetero-resistant vancomycin intermediate Staphylococcus aureus bacteremia in a Taiwan Medical Center.
机构信息
Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
出版信息
J Microbiol Immunol Infect. 2012 Dec;45(6):435-41. doi: 10.1016/j.jmii.2012.05.004. Epub 2012 Jun 30.
BACKGROUND
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.
METHODS
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.
RESULTS
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.
CONCLUSION
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.
背景
异质性万古霉素中介金黄色葡萄球菌（hVISA）在最近十年在全球范围内出现。本研究的目的是调查糖肽使用趋势、耐甲氧西林金黄色葡萄球菌（MRSA）对万古霉素敏感性降低的流行率、对新型抗菌药物的敏感性率、分子流行病学、临床特征以及台湾一家医疗中心金黄色葡萄球菌菌血症患者的预后。
方法
在台湾一家医疗中心，从 2009 年 3 月至 12 月期间，对 118 株金黄色葡萄球菌血培养分离株进行了研究，用 Etest 宏法筛选了 62 株 MRSA 分离株 hVISA，并进一步用改良的群体分析谱法进行了确认。对 hVISA 分离株进行了分子分型。
结果
有 5（4.2%）株分离株为 hVISA。与非 hVISA-MRSA 相比，hVISA 分离株对环丙沙星、庆大霉素、复方新诺明和四环素的耐药率更高。在感染 MRSA 的患者中，hVISA 感染患者的住院死亡率高于非 hVISA 组（60%比 17.5%，p=0.025）。所有 hVISA 分离株均为医院获得性感染，且脉冲场凝胶电泳带型不同。4 株 hVISA 分离株携带 III 型葡萄球菌盒式染色体 mec（SCCmec），其余分离株携带 SCCmec 型 II。5 株 hVISA 分离株中有 3 株属于 239 型序列，这是台湾最常见的类型。研究医院糖肽使用量增加；然而，这些 hVISA 感染患者在最近 6 个月内没有接受糖肽治疗。
结论
我们的研究结果表明，在我们观察到台湾 hVISA 最高发生率之前，hVISA 可能已经在医院中传播，并且增加糖肽的使用可能是选择压力。迫切需要采取措施防止传播耐万古霉素敏感性降低的 MRSA 并治疗此类感染。
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