Ryu Hyejin, Park Yeon-Joon, Kim Yong-Kyun, Chang Jiyoung, Yu Jin Kyung
Department of Laboratory Medicine, Seoul St. Mary's Hospital, School of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
Department of Laboratory Medicine, Seoul St. Mary's Hospital, School of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
J Infect Chemother. 2014 Aug;20(8):509-11. doi: 10.1016/j.jiac.2014.03.005. Epub 2014 May 28.
Streptococcus agalactiae has emerged as an important cause of invasive infection in adults. Forty-nine S. agalactiae isolates (41 from adults and 8 from neonates) were collected during a 4-year period (2010-2013) and analyzed by multilocus sequence typing (MLST). Antibiotic susceptibility to erythromycin, clindamycin and levofloxacin was determined and the determinants of resistance (ermA, ermB, ermC, mefA, lnuB) were detected by PCR and mutation in gyrA, gyrB, parC and parE gene was investigated by sequence analysis. They were resolved into 14 sequence types (STs) and belonged to five clonal complexes (CCs). The distribution of CC was significantly different according to the age group; CC1 (18/41) and CC10 (13/41) was the most common among the adult isolates but CC19 (5/8) was predominant among the neonatal isolates. The resistance rate to erythromycin, clindamycin was 18.4% and 24.5%, respectively. Among the 13 strains resistant to erythromycin and/or clindamycin, two isolates harbored ermA and 10 isolates harbored ermB. The levofloxacin resistance rate was very high (32.7%) and was significantly higher in CC10 (71.4%). All the levofloxacin-resistant isolates had identical gyrA substitution (Ser81Leu) but parC substitution was different according to the CCs. The additional mutation in parE (His221Tyr) was found only in CC19. Continuous monitoring of the fluoroquinolone resistance and genotypic distribution among S. agalactiae is needed.
无乳链球菌已成为成人侵袭性感染的重要病因。在4年期间（2010 - 2013年）收集了49株无乳链球菌分离株（41株来自成人，8株来自新生儿），并通过多位点序列分型（MLST）进行分析。测定了对红霉素、克林霉素和左氧氟沙星的抗生素敏感性，并通过PCR检测耐药决定簇（ermA、ermB、ermC、mefA、lnuB），通过序列分析研究gyrA、gyrB、parC和parE基因中的突变。它们被分为14种序列类型（STs），并属于五个克隆复合体（CCs）。CC的分布根据年龄组有显著差异；CC1（18/41）和CC10（13/41）在成人分离株中最常见，但CC19（5/8）在新生儿分离株中占主导。对红霉素、克林霉素的耐药率分别为18.4%和24.5%。在13株对红霉素和/或克林霉素耐药的菌株中，2株分离株携带ermA，10株携带ermB。左氧氟沙星耐药率非常高（32.7%），在CC10中显著更高（71.4%）。所有左氧氟沙星耐药分离株具有相同的gyrA替代（Ser81Leu），但parC替代根据CCs不同。parE中的额外突变（His221Tyr）仅在CC19中发现。需要持续监测无乳链球菌中氟喹诺酮耐药性和基因型分布。
