Lu J J, Perng C L, Ho M F, Chiueh T S, Lee W H
Division of Clinical Pathology and Experimental Pathology, Department of Pathology, Tri-Service General Hospital and National Defense Medical Center, No. 325, Section 2, Chengkung Rd., Taipei 114, Taiwan, Republic of China.
J Clin Microbiol. 2001 Jun;39(6):2140-5. doi: 10.1128/JCM.39.6.2140-2145.2001.
Thirty-six VanB glycopeptide-resistant Enterococcus faecium isolates were collected from patients in five different hospitals in Taiwan. The vancomycin resistance genes were amplified by the long vanB PCR, which amplifies the 6,373-bp vanB gene cluster including the vanR(B2), vanS(B2), vanY(B2), vanW(B2), vanH(B2), vanB2, and vanX(B2) genes. The deduced amino acid sequences were found to be 95 to 98% homologous to those of the vanB1 gene cluster: VanR(B1), 97%; VanS(B1), 97%; VanY(B1), 96%; VanH(B1), 95%; VanB1, 96%; and VanX(B1), 98%. Restriction enzyme analysis of the long vanB PCR products revealed that all 36 isolates had the same vanB2-specific pattern. DNA sequence analysis of the vanB2 gene, which is a D-Ala-D-Lac ligase gene, revealed that none of the 36 sequences were identical to the previously published vanB2 sequence. Thirty-one isolates had 1 nucleotide different from the published vanB2 sequence. The sequences of the other five isolates differed from the published vanB2 sequence by 2 or 3 nucleotides. Four isolates with a low or moderate resistance to vancomycin (MIC = 4 to 32 microg/ml) were found to have the same leucine-to-methionine change at amino acid position 308 of the vanB2 gene. The genomic DNAs of all 36 isolates were digested with SmaI and then typed by pulsed-field gel electrophoresis (PFGE). Eight different PFGE types (I to VIII) were observed, and type I was found to be prevalent in all hospitals examined in this study. This result suggests that intra- and interhospital dissemination of this E. faecium strain has occurred in Taiwan.
从台湾五家不同医院的患者中收集了36株耐万古霉素的粪肠球菌VanB分离株。通过长vanB PCR扩增万古霉素抗性基因,该方法可扩增包含vanR(B2)、vanS(B2)、vanY(B2)、vanW(B2)、vanH(B2)、vanB2和vanX(B2)基因的6373 bp vanB基因簇。推导的氨基酸序列与vanB1基因簇的氨基酸序列同源性为95%至98%:VanR(B1)为97%;VanS(B1)为97%;VanY(B1)为96%;VanH(B1)为95%;VanB1为96%;VanX(B1)为98%。对长vanB PCR产物进行限制性酶切分析表明,所有36株分离株具有相同的vanB2特异性模式。对作为D - Ala - D - Lac连接酶基因的vanB2基因进行DNA序列分析发现,36个序列中没有一个与先前发表的vanB2序列相同。31株分离株与已发表的vanB2序列有1个核苷酸不同。其他5株分离株的序列与已发表的vanB2序列相差2或3个核苷酸。发现4株对万古霉素低或中度耐药(MIC = 4至32 μg/ml)的分离株在vanB2基因的第308位氨基酸处有相同的亮氨酸到甲硫氨酸的变化。用SmaI消化所有36株分离株的基因组DNA,然后通过脉冲场凝胶电泳(PFGE)进行分型。观察到8种不同的PFGE类型(I至VIII),并且发现I型在本研究中检测的所有医院中都很普遍。这一结果表明,这种粪肠球菌菌株已在台湾医院内和医院间传播。