Genetical and epidemiological analysis of enterococci resistant to vancomycin

Research Project

Project/Area Number	07672492
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Laboratory medicine
Research Institution	University of the Ryukyus (1996) Kumamoto University (1995)
Principal Investigator	YAMANE Nobuhisa University of the Ryukyus, Faculty of Medicine, Department of Laboratory Medicine, Professor, 医学部, 教授 (80125682)
Project Period (FY)	1995 – 1996
Project Status	Completed (Fiscal Year 1996)
Budget Amount *help	¥2,100,000 (Direct Cost: ¥2,100,000) Fiscal Year 1996: ¥600,000 (Direct Cost: ¥600,000) Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	Vancomycin-resistant enterococci / VanA resistance / VanB resistance / antimicrobial susceptibility testing / polymerase chain reaction / 耐性スクリーニング培地 / プラスミド解析 / パルス・フィールド電気泳動 / バンコマイシン / 腸球菌 / 耐性伝達 / 遺伝子解析 / 薬剤感受性検査 / 疫学調査
Research Abstract	The study was conducted to evaluate the test methods available in Japan to discriminate between the isolates of enterococci resistant to vancomycin (VRE) and those susceptible (VSE). Among the phenotypic test methods evaluated, an agar screening method which utilized 8 mug per ml of vancomycin in Mueller-Hinton agar appeared to have a sufficient accuracy, the results indicating 98.3% of sensitivity and 100% of specificity to detect VRE.Also, all the VRE isolates were interpreted as being resistant or intermediate by the E test when the results were read after 48 hr-incubation. Whereas, two disk diffusion tests, Showa disk and NCCLS-based Sensi-disc, were evaluated, but both failed to discriminate between VRE and VSE,in particular, between the isolates with vanB positive and negative. The automated system, Vitek GPS-TA produced high frequencies of very majior errors ; 8.7% for vanA positives and 58% for vanB positives. A total of 1,214 enterococcal isolates from multisite laboratories in Japan, comprising 7 different species, were first tested onto agar screening test plates, but none of isolates represented phenotypic vancomycin resistance.