High prevalence of multidrug-resistant international clones among macrolide-resistant Streptococcus pneumoniae isolates in immunocompromised patients in Tunisia
High prevalence of multidrug-resistant international clones among macrolide-resistant Streptococcus pneumoniae isolates in immunocompromised patients in Tunisia
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DOI：
10.1016/j.ijantimicag.2018.04.015
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发表时间：
2018-12-01
影响因子：
10.8
通讯作者：
Benhassen, Assia
中科院分区：
文献类型：
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作者：
Raddaoui, Anis;Ben Tanfous, Farah;Benhassen, Assia
目的：大环内酯类耐药肺炎链球菌分离株在过去十年中显著增加，在相关表型和基因型中具有重要的地理变异。本研究的目的是调查耐大环内酯类抗生素沙门氏菌的表型、基因型、血清型和遗传相关性。方法：采用纸片扩散法测定抗生素敏感性，Etest法测定红霉素和克林霉素对大环内酯类抗生素耐药菌株的MIC。通过PCR对ermB、mefA、tetM、tetO和Int-Tn 1545的大环内酯类耐药分离株进行分析。通过多重PCR和Quellung反应进行血清分型。结果：59株分离株中有41株（69.5%）对大环内酯类抗生素耐药。在41株分离株中，37株（90.2%）具有大环内酯-林可酰胺-链阳性菌素B（MLSB）耐药表型，以高水平诱导MLSB表型为主，并携带ermB基因。所有具有高水平诱导MLSB表型的分离株对红霉素和克林霉素高度耐药。4株（9.8%）具有大环内酯类（M）耐药表型，并携带mefA基因。红霉素耐药菌株中97.5%为多药耐药（MDR），12.2%为广泛耐药。分离株基本上属于4种血清型（19 F、23 F、14和6 B）。它们主要归属于3种序列类型（ST 81、ST 2918和ST 386）。结论：Tn 1545转座子和三个MDR国际克隆的高流行率是导致沙门氏菌多药耐药的重要原因。肺炎分离株。(c)2018 Elsevier B. V.和国际化疗学会。All rights reserved.
Objectives: Macrolide-resistant Streptococcus pneumoniae isolates have increased considerably in the last decade, with important geographical variations in involved phenotypes and genotypes. The aim of this study was to investigate phenotypes, genotypes, serotypes and genetic relatedness of macrolide-resistant S. pneumoniae isolated from immunocompromised patients in Tunisia.Methods: Antibiotic susceptibility was determined by disk diffusion, and MICs of erythromycin and clindamycin were determined for macrolide-resistant isolates by Etest. Macrolide-resistant isolates were analysed by PCR for ermB, mefA, tetM, tetO and Int-Tn 1545. Serotyping was done by multiplex PCR and the Quellung reaction. Multilocus sequence typing (MLST) was performed for molecular typing.Results: Macrolide resistance was observed in 41 (69.5%) of 59 isolates. Of the 41 isolates, 37 (90.2%) had a macrolide-lincosamide-streptogramin B (MLSB) resistance phenotype, with a predominance of high-level inducible MLSB phenotype, and harboured the ermB gene. All isolates with high-level inducible MLSB phenotype were highly resistant to erythromycin and clindamycin. Four isolates (9.8%) had a macrolide (M) resistance phenotype and harboured the mefA gene. Erythromycin-resistant isolates were multidrug-resistant (MDR) in 97.5% of cases and extensively drug-resistant in 12.2%. The isolates belonged essentially to four serotypes (19F, 23F, 14 and 6B). They were mainly assigned to three sequence types (ST81, ST2918 and ST386). Also, 65.9% of the isolates were grouped in three clonal complexes (CC81, CC838 and CC386).Conclusions: These data indicate a high prevalence of Tn 1545 transposon and of three MDR international clones contributing to the high frequency of multidrug resistance among S. pneumoniae isolates in our centre. (c) 2018 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.