Pryce T M, Wilson R D, Kulski J K
Department of Microbiology and Infectious Diseases, Royal Perth Hospital, WA, Australia.
J Microbiol Methods. 1999 Jun;36(3):147-55. doi: 10.1016/s0167-7012(99)00026-3.
Enterococci are frequently associated with hospital-acquired infection. Identification of enterococci using conventional biochemical tests are often tedious to perform in a routine diagnostic laboratory and may give equivocal results. This study evaluates the usefulness of ribotyping by DNA hybridisation to identify 68 members of the bacterial genus Enterococcus characterised by a conventional test scheme. DNA probes (830 bp in size) were derived from the 16S rRNA gene of E. coli or E. faecalis by PCR, labelled with horseradish peroxidase and used in Southern blot hybridisations of enterococcal DNA digested with EcoRI. Unique ribotypes were obtained for 11 different species using 12 Enterococcus type strains. Ribotyping identified 44 E. faecalis isolates, 19 E. faecium isolates, two E. durans isolates and one E. avium isolate in concordance with results of the biochemistry tests. Two isolates that had ribotype patterns identical to the E. faecium type strain were unable to be definitively identified by biochemical tests. The results show that ribotyping is able to differentiate between E. faecium and E. faecalis and may be useful for identifying other enterococci in the hospital setting. In addition, ribotyping using DNA probes and enhanced chemiluminescence is a safe and more reproducible alternative to radiolabelling RNA in a clinical microbiology laboratory.
肠球菌常与医院获得性感染相关。在常规诊断实验室中，使用传统生化试验鉴定肠球菌往往操作繁琐，且可能得出模棱两可的结果。本研究评估了通过DNA杂交进行核糖体分型以鉴定68株经传统试验方案鉴定的肠球菌属细菌的实用性。DNA探针（大小为830 bp）通过PCR从大肠杆菌或粪肠球菌的16S rRNA基因中获得，用辣根过氧化物酶标记，并用于经EcoRI消化的肠球菌DNA的Southern印迹杂交。使用12株肠球菌标准菌株为11个不同物种获得了独特的核糖体分型。核糖体分型鉴定出44株粪肠球菌分离株、19株屎肠球菌分离株、2株耐久肠球菌分离株和1株鸟肠球菌分离株，与生化试验结果一致。两株核糖体分型模式与屎肠球菌标准菌株相同的分离株无法通过生化试验进行明确鉴定。结果表明，核糖体分型能够区分屎肠球菌和粪肠球菌，可能有助于在医院环境中鉴定其他肠球菌。此外，在临床微生物学实验室中，使用DNA探针和增强化学发光的核糖体分型是一种比放射性标记RNA更安全、更可重复的替代方法。
