Emaneini Mohammad, Jabalameli Fereshteh, Mirsalehian Akbar, Ghasemi Amir, Beigverdi Reza
Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Department of Microbiology and Immunology, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran.
Microb Pathog. 2016 Oct;99:119-122. doi: 10.1016/j.micpath.2016.08.016. Epub 2016 Aug 20.
Between January and December 2013, swab samples were taken for the throat and external ear canals of 1037 newborns for screening of Group B Streptococcus (GBS or S. agalactiae). Isolates were analyzed form Multilocus sequence typing (MLST), capsular type, virulence genes and antibiotic susceptibility. The MLST analysis of 19 GBS isolates showed 8 sequence types (STs). Overall the most common STs were ST19 and ST28. Other STs were ST1, ST4, ST8, ST12, ST335 and ST734 (a new ST). The most common clonal complexes (CCs) were CC19 (68.4%) and CC10 (21%). The scpB, hlyB and bca virulence genes were detected in all ST, while the bac gene was predominant in ST12 with capsular type (CT) Ib. The IS1548 and the rib genes were particularly prevalent in CTIII and were detected in isolates belong to ST19, ST335 and ST734 and were grouped in CC19. All isolates were susceptible to penicillin, vancomycin, linezolid and quinupristin-dalfopristin. Resistance to tetracycline was observed in all 19 (100%) strains and was correlated with presence of the tetM gene except for one isolate with ST12. All the ST8 and ST12 isolates were resistant to macrolide carrying two resistance genes; the ermTR and the ermB, respectively. The results of this study showed that the CC19 was a major clone in the neonatal intensive care unit (NICU) of Imam Khomeini hospital which can cause severe infections in susceptible neonates (particularly in premature infants). As a result, an intensive infection control policy is needed to prevent the spread of this clone.
2013年1月至12月期间，采集了1037名新生儿的咽喉和外耳道拭子样本，用于筛查B族链球菌（GBS或无乳链球菌）。对分离株进行多位点序列分型（MLST）、荚膜型、毒力基因和抗生素敏感性分析。对19株GBS分离株的MLST分析显示有8种序列类型（STs）。总体而言，最常见的STs是ST19和ST28。其他STs是ST1、ST4、ST8、ST12、ST335和ST734（一种新的ST）。最常见的克隆复合体（CCs）是CC19（68.4%）和CC10（21%）。在所有ST中均检测到scpB、hlyB和bca毒力基因，而bac基因在荚膜型（CT）Ib的ST12中占主导地位。IS1548和rib基因在CTIII中特别普遍，在属于ST19、ST335和ST734且归为CC19的分离株中检测到。所有分离株对青霉素、万古霉素、利奈唑胺和奎奴普丁-达福普汀敏感。在所有19株（100%）菌株中均观察到对四环素的耐药性，除一株ST12分离株外，均与tetM基因的存在相关。所有ST8和ST12分离株分别携带ermTR和ermB这两个耐药基因，对大环内酯类耐药。本研究结果表明，CC19是伊玛目霍梅尼医院新生儿重症监护病房（NICU）中的主要克隆株，可在易感新生儿（尤其是早产儿）中引起严重感染。因此，需要制定强化感染控制政策以防止该克隆株的传播。
