伊朗伊斯法罕市孕妇和非孕妇定植和侵袭性无乳链球菌分离株中红霉素耐药株的流行率、人群结构、血清型分布、菌毛岛和耐药基因。
Prevalence, population structure, distribution of serotypes, pilus islands and resistance genes among erythromycin-resistant colonizing and invasive Streptococcus agalactiae isolates recovered from pregnant and non-pregnant women in Isfahan, Iran.
机构信息
Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Hezar-Jerib Street, Isfahan, Iran.
Department of Gynecology and Obstetrics, Al-Zahra university Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
出版信息
BMC Microbiol. 2021 May 4;21(1):139. doi: 10.1186/s12866-021-02186-2.
BACKGROUND
The information on antibiotic resistance and molecular features of Group B Streptococcus (GBS) are essential for epidemiological purposes as well as vaccine development. Therefore, we aimed to assess the antimicrobial resistance profiles and molecular characteristics of GBS isolates in Isfahan, Iran. A total number of 72 colonizing and invasive GBS were collected from pregnant and non-pregnant women. The GBS isolates were analyzed for resistance profiles, capsular genotyping, and detection of PI-1, PI-2a, PI-2b, hvgA, ermB, ermTR, lnuB and, mefA genes. Besides, erythromycin-resistant strains were subjected to multilocus sequence typing (MLST).
RESULTS
The prevalence of colonizing and invasive GBS were 11 and 0.05%, respectively. The frequency of capsular serotypes was as follows: III (26.3%), Ia (20.83%), Ib and V (each 15.2%), IV (9.7%), II (8.3%), VII (2.7%), and VI (1.3%). Overall frequencies of PIs were as follows: PI-1, 37.5%, PI-1 + PI-2a, 30.5%, PI-1 + PI-2b, 29.1% and PI-2b, 2.7%. Two maternal colonizing GBS (2.6%) were hvgA positive and were belonged to ST-17/CPS-III/PI-1 + PI-2b lineage. Among 30(41.6%) erythromycin resistant GBS, 21 isolates (70%) harbored ermB gene, followed by ermTR (23.3%) and mefA (10%). One clindamycin-resistant isolate harbored the lnuB gene. MLST analysis revealed the following five clonal complexes (CCs) and nine STs: (CC-19/ST-335, ST-19, and ST-197), (CC-12/ST-43, ST-12), (CC-23/ST-163, ST-23), (CC-17/ST-17) and (CC-4/ST-16).
CONCLUSION
The study shows an alarmingly high prevalence of erythromycin-resistant GBS in Iran. In addition, we report dissemination of ST-335/CPS-III clone associated with tetracycline and erythromycin resistance in our region. The distribution of capsular and pilus genotypes varies between invasive and colonizing GBS that could be helpful for vaccine development.
背景
了解 B 群链球菌（GBS）的抗生素耐药性和分子特征对于流行病学研究和疫苗开发至关重要。因此，我们旨在评估伊朗伊斯法罕地区 GBS 分离株的抗生素耐药谱和分子特征。从孕妇和非孕妇中采集了 72 株定植和侵袭性 GBS 进行研究。分析了 GBS 分离株的耐药谱、荚膜基因分型以及 PI-1、PI-2a、PI-2b、hvgA、ermB、ermTR、lnuB 和 mefA 基因的检测。此外，对红霉素耐药菌株进行了多位点序列分型（MLST）分析。
结果
定植和侵袭性 GBS 的检出率分别为 11%和 0.05%。荚膜血清型的频率如下：III 型（26.3%）、Ia 型（20.83%）、Ib 和 V 型（各 15.2%）、IV 型（9.7%）、II 型（8.3%）、VII 型（2.7%）和 VI 型（1.3%）。PI 的总频率如下：PI-1，37.5%；PI-1+PI-2a，30.5%；PI-1+PI-2b，29.1%；PI-2b，2.7%。2 株产妇定植 GBS（2.6%）hvgA 阳性，属于 ST-17/CPS-III/PI-1+PI-2b 谱系。在 30 株（41.6%）红霉素耐药 GBS 中，21 株（70%）携带 ermB 基因，其次是 ermTR（23.3%）和 mefA（10%）。1 株克林霉素耐药株携带 lnuB 基因。MLST 分析显示以下 5 个克隆复合体（CC）和 9 个 ST：（CC-19/ST-335、ST-19 和 ST-197）、（CC-12/ST-43、ST-12）、（CC-23/ST-163、ST-23）、（CC-17/ST-17）和（CC-4/ST-16）。
结论
本研究表明，伊朗红霉素耐药 GBS 的流行率令人震惊。此外，我们报告了与四环素和红霉素耐药相关的 ST-335/CPS-III 克隆在本地区的传播。定植和侵袭性 GBS 之间荚膜和菌毛基因型的分布不同，这可能有助于疫苗开发。
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