Comparative evaluation of VITEK 2® for antimicrobial susceptibility testing of group B Streptococcus
Comparative evaluation of VITEK 2® for antimicrobial susceptibility testing of group B Streptococcus
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DOI：
10.1093/jac/dkm098
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发表时间：
2007-06-01
影响因子：
5.2
通讯作者：
Poyart, Claire
中科院分区：
文献类型：
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作者：
Tazi, Asmaa;Reglier-Poupet, Helene;Poyart, Claire
目的：产时抗生素预防被推荐用于预防定植妇女的新生儿B族链球菌（GBS）疾病，青霉素或氨基青霉素构成一线抗生素。大多数分离株对四环素耐药，对大环内酯类-林可酰胺链菌素（MLS）抗生素的耐药性正在增加。因此，现在建议对青霉素过敏患者进行GBS MLS耐药性的实验室检测。本研究的目的是比较GBS的抗菌药物敏感性的VITEK 2系统（bioMerieux，Marcy l 'Etoile，法国），琼脂扩散法和PCR-耐药基因的基因型检测。检测的抗生素（VITEK 2和琼脂扩散法）为苄青霉素、氨苄青霉素、红霉素、克林霉素、复方新诺明、四环素、卡那霉素、链霉素和万古霉素。对MLS抗生素进行标准化双纸片（DD）扩散试验。结果：所有菌株均对青霉素、氨苄青霉素和万古霉素敏感[VITEK 2与扩散法的分类一致率（CA）为100%]。95株（86%）对四环素耐药（CA为98.9%）。81株（73.6%）具有MLS抗性表型，50株（61.8%）具有MLSB组成型表型，25株（30.8%）具有MLSB诱导型表型，6株（7.4%）具有M表型。VITEK 2和DD扩散试验检测MLSB组成型、MLSB诱导型和M表型分离株的数据之间的一致性分别为76%、36%和100%。结论：VITEK 2能准确测定GBS对大多数抗生素的敏感性，但对红霉素的敏感性有待提高。因此，DD扩散试验仍然是最简单和可靠的方法，大环内酯类耐药检测链球菌种。
Objectives: Intrapartum antibiotic prophylaxis is recommended to prevent neonatal group B streptococcal (GBS) disease in colonized women, and penicillin or aminopenicillin constitute the first-line antibiotics. Most isolates are resistant to tetracycline, and resistance to macrolide-lincosamidestreptogramin (MLS) antibiotics is increasing. Therefore, laboratory testing for MLS resistance in GBS is now recommended for penicillin-allergic patients. The aim of this study was to compare the antimicrobial susceptibility of GBS as determined by the VITEK 2 system (bioMerieux, Marcy l'Etoile, France), agar diffusion methods and PCR-genotypic detection of resistance genes.Methods: One hundred and ten unrelated selected GBS clinical isolates were studied. The antibiotics tested (VITEK 2 and agar diffusion method) were benzylpenicillin, ampicillin, erythromycin, clindamycin, co-trimoxazole, tetracycline, kanamycin, streptomycin and vancomycin. A standardized double-disc (DD) diffusion test was performed for MLS antibiotics. Genotypic characterization of tetracycline, MLS and aminoglycoside resistance genes was performed by PCR.Results: All strains were susceptible to benzylpenicillin, ampicillin and vancomycin [category agreement (CA) between VITEK 2 and the diffusion method was 100%]. Ninety-five (86%) strains were resistant to tetracycline (CA was 98.9%). Eighty-one strains (73.6%) harboured an MLS resistance phenotype; 50 (61.8%) an MLSB-constitutive phenotype, 25 (30.8%) an MLSB-inducible phenotype and 6 (7.4%) an M phenotype. The agreement between data of VITEK 2 and the DD diffusion test for the detection of MLSB-constitutive, MLSB-inducible and M phenotype isolates was 76%, 36% and 100%, respectively. Almost all discrepancies were due to failure to detect erythromycin resistance by VITEK 2.Conclusions: VITEK 2 allows accurate determination of GBS susceptibility for the majority of antibiotics, but has to be improved for erythromycin. Thus, the DD diffusion test remains the most simple and reliable method for macrolide resistance detection among this streptococcal species.