Brown Derek F J, Walpole Enid
Clinical Microbiology and Public Health Laboratory, Addenbrooke's Hospital, Cambridge CB2 2QW, UK.
J Antimicrob Chemother. 2003 Feb;51(2):289-96. doi: 10.1093/jac/dkg076.
Vancomycin-resistant enterococcus enrichment broth (VEB) and vancomycin-resistant enterococcus selective agar with vancomycin 6 mg/L (VSA) are novel azide-aesculin agar-based media that contain meropenem as an additional selective agent. The media were compared with enterococcosel broth (EB) and enterococcosel agar with vancomycin 6 mg/L (EA) for the isolation of glycopeptide-resistant enterococci (GRE) from routine faecal screening specimens.
Two hundred and eighteen routine faecal screening specimens from patients at Addenbrooke's Hospital were examined. The majority were from patients on haematology wards (155) or the intensive therapy unit (ITU) (21). Specimens were inoculated on to VSA and EA directly, and after enrichment in VEB and EB, respectively.
One hundred and twenty-eight GRE isolates were recovered from 93 (43%) specimens with enterococci carrying vanA or vanB genes. There were no statistically significant differences between media (specimens positive; numbers of GRE isolates) on direct plating on VSA (87; 104) or EA (86; 97) or following 24 h enrichment in VEB (89; 103) or EB (86; 98). There was no significant advantage to enrichment compared with direct plating. Incubation of enrichment broth cultures for only 6 h appeared detrimental. Enterococci with vanC were isolated significantly less frequently from VEB and VSA than from EB and EA. Growth of organisms other than GRE was more common on VSA than on EA.
VEB and VSA were at least as effective as EB and EA for the recovery of GRE from faecal screening specimens, but substantially more non-GRE grew on VSA than on EA. Enrichment culture offered no significant advantages over direct plating.
耐万古霉素肠球菌增菌肉汤（VEB）和含6mg/L万古霉素的耐万古霉素肠球菌选择性琼脂（VSA）是新型的基于叠氮硫酸铁琼脂的培养基，其中含有美罗培南作为额外的选择剂。将这些培养基与肠球菌肉汤（EB）和含6mg/L万古霉素的肠球菌琼脂（EA）进行比较，用于从常规粪便筛查标本中分离耐糖肽肠球菌（GRE）。
对来自阿登布鲁克医院患者的218份常规粪便筛查标本进行检测。大多数标本来自血液科病房的患者（155份）或重症监护病房（ITU）的患者（21份）。标本分别直接接种于VSA和EA上，并分别在VEB和EB中增菌后接种。
从93份（43%）标本中分离出128株GRE，这些标本中的肠球菌携带vanA或vanB基因。在VSA（87；104）或EA（86；97）上直接接种，或在VEB（89；103）或EB（86；98）中增菌24小时后，各培养基之间（标本阳性；GRE分离株数量）无统计学显著差异。与直接接种相比，增菌没有显著优势。仅将增菌肉汤培养物孵育6小时似乎有害。与EB和EA相比，从VEB和VSA中分离出携带vanC的肠球菌的频率显著更低。VSA上非GRE菌的生长比EA上更常见。
VEB和VSA在从粪便筛查标本中回收GRE方面至少与EB和EA一样有效，但VSA上生长的非GRE菌比EA上多得多。增菌培养相对于直接接种没有显著优势。
