Lo Hsueh-Hsia, Nien Hao-Hsiang, Cheng Ya-Yu, Su Fang-Yi
Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan.
Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan.
J Microbiol Immunol Infect. 2015 Dec;48(6):613-7. doi: 10.1016/j.jmii.2014.04.003. Epub 2014 May 22.
BACKGROUND/PURPOSE: Information concerning antibiotics susceptibilities of beta-hemolytic group G Streptococcus dysgalactiae subspecies equisimilis (SDSE) clinical isolates in central Taiwan was limited.
Totally, 246 SDSE isolates were collected from mainly five regional hospitals, from February 2007 to August 2011. Disk diffusion method, broth microdilution method, and clindamycin induction test (D test) were respectively performed according to the guidelines of the Clinical and Laboratory Standards Institute. Polymerase chain reaction was used to detect the corresponding erythromycin resistance genes.
All isolates were susceptible to penicillin, cefotaxime, and vancomycin. The rate of erythromycin resistance was 24.0% (59/246), whereas that of clindamycin resistance was 12.2% (30/246). The resistance rates of isolates from different hospitals varied from 15.0% to 45.5% for erythromycin and from 7.1% to 36.4% for clindamycin. For erythromycin-resistant SDSE isolates, three different phenotypes with resistance to macrolides (M), lincosamides (L), and type B streptogramins (SB) were observed: M (49.2%), constitutive MLSB (cMLSB, 35.6%), and inducible MLSB (iMLSB, 15.3%). All M phenotypic isolates carried mefA. The most prevalent genotypes among cMLSB and iMLSB phenotypic isolates were ermB, followed by ermTR. One isolate with cMLSB phenotype carried both ermB and ermTR, whereas one isolate with iMLSB phenotype carried both ermB and ermC.
This is the first trial investigating the antimicrobial susceptibility pattern and erythromycin resistance mechanisms of beta-hemolytic group G SDSE isolates in central Taiwan. The resistance rates for both erythromycin and clindamycin varied significantly among hospitals located in this area and should be monitored continuously in the future.
背景/目的：台湾中部地区β-溶血性G群马链球菌似马亚种（SDSE）临床分离株的抗生素敏感性相关信息有限。
2007年2月至2011年8月期间，共从主要五家地区医院收集了246株SDSE分离株。根据临床和实验室标准协会的指南，分别采用纸片扩散法、肉汤微量稀释法和克林霉素诱导试验（D试验）。采用聚合酶链反应检测相应的红霉素耐药基因。
所有分离株对青霉素、头孢噻肟和万古霉素敏感。红霉素耐药率为24.0%（59/246），而克林霉素耐药率为12.2%（30/246）。不同医院分离株的红霉素耐药率在15.0%至45.5%之间，克林霉素耐药率在7.1%至36.4%之间。对于红霉素耐药的SDSE分离株，观察到三种对大环内酯类（M）、林可酰胺类（L）和B型链阳菌素（SB）耐药的不同表型：M（49.2%）、组成型MLSB（cMLSB，35.6%）和诱导型MLSB（iMLSB，15.3%）。所有M表型分离株均携带mefA。cMLSB和iMLSB表型分离株中最常见的基因型是ermB，其次是ermTR。一株cMLSB表型分离株同时携带ermB和ermTR，而一株iMLSB表型分离株同时携带ermB和ermC。
这是首次对台湾中部地区β-溶血性G群SDSE分离株的抗菌药物敏感性模式和红霉素耐药机制进行的研究。该地区各医院的红霉素和克林霉素耐药率差异显著，未来应持续监测。
