Glycopeptide-intermediate Staphylococcus aureus:: Evaluation of a novel screening method and results of a survey of selected US hospitals
Glycopeptide-intermediate Staphylococcus aureus:: Evaluation of a novel screening method and results of a survey of selected US hospitals
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DOI：
10.1128/jcm.37.11.3590-3593.1999
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发表时间：
1999-11-01
影响因子：
9.4
通讯作者：
Tenover, FC
中科院分区：
文献类型：
--
作者：
Hubert, SK;Mohammed, JM;Tenover, FC
在美国和其他地方出现了对糖肽类抗菌剂，如万古霉素和替考拉宁敏感性降低的金黄色葡萄球菌分离株。先前的一项研究表明，商业制备的脑心输注琼脂(BHIA)每英里添加6毫克万古霉素可以检测糖肽中间体金黄色葡萄球菌(GISA)，具有高敏感性和特异性；然而，当该介质在内部配制时，偶尔会显示对万古霉素敏感的对照微生物的生长。这一限制可能会显著影响实验室在内部准备培养基时，特别是如果他们希望对GISA进行大规模监测研究的话，因此，用内部制备的含有万古霉素的Mueller-Hinton琼脂(MWA)代替商业制备的BHIA进行了一项检测GISA的中试研究，选择MNA进行这项研究，因为这种培养基普遍可用且标准化程度很好，试点研究的结果表明，在MHA中添加每英里5 MU万古霉素是筛选GISA分离株的一种敏感而特异的方法。用该方法对1997年从美国33家医院收集的630株耐甲氧西林金黄色葡萄球菌S进行GISA法筛选。14株金黄色葡萄球菌虽然在筛选琼脂上生长，但肉汤微量稀释法均为万古霉素敏感(MIC值小于或等于1µg/ml)。对5株万古霉素耐药菌株进行群体分析，发现其中2株具有万古霉素MIC为8微克/毫升的亚群。总之，自制的万古霉素MIC为万古霉素MIC为8微克/毫升的GISA的MHA筛查提供了一种灵敏而经济的方法。然而，确认为万古霉素耐药是至关重要的，这项研究表明，1997年GISA在美国并不普遍存在。
Isolates of Staphylococcus am eus with decreased susceptibilities to glycopeptide antimicrobial agents, such as vancomycin and teicoplanin, have emerged in the United States and elsewhere, Commercially prepared brain heart infusion agar (BHIA) supplemented with 6 mu g of vancomycin per mi was shown in a previous study to detect glycopeptide-intermediate S. aureus (GISA) with high sensitivity and specificity; however, this medium, when prepared in-house, occasionally showed growth of vancomycin-susceptible control organisms. This limitation could significantly impact laboratories that prepare media in-house, particularly if they wished to conduct large surveillance studies for GISA, Therefore, a pilot study to detect GISA was performed with vancomycin-containing Mueller-Hinton agar (MWA) prepared in-house in place of commercially prepared BHIA, MNA was selected for this study because this medium is widely available and well standardized, The results of the pilot study showed that supplementation of MHA with 5 mu g of vancomycin per mi was both a sensitive and a specific method for screening for GISA isolates. This method was used to screen for GISA among 630 clinical isolates of methicillin-resistant S, aureus collected during 1997 from 33 U.S. hospitals, Although 14 S. aureus isolates grew on the screening agar, all were vancomycin susceptible (MICs were less than or equal to 1 mu g/ml) by broth microdilution testing. Population analyses of five isolates revealed two with a subpopulation for which vancomycin MICs were 8 mu g/ml. In summary, the MHA screen plate containing 5 pg of vancomycin per mi prepared in-house provides a sensitive and cost-effective method for large-scale screening for GISA for which vancomycin MICs are 8 mu g/ml. However, confirmation of isolates as vancomycin resistant is critical, This study suggests that GISA was not a widespread problem in the United States in 1997.