Aix Marseille University, IRD, SSA, Vitrome, IHU Mediterranee Infection, 19-21 Bd Jean Moulin, 13005 Marseille, France.
Microbiology Laboratory, A. Mami Hospital of Pneumology, UR12/SP18, Ariana, Tunisia.
J Med Microbiol. 2020 Apr;69(4):505-520. doi: 10.1099/jmm.0.001151.
. is responsible for many community infections, with the main ones being pneumonia and meningitis. Pneumococcus has developed increased resistance to multiple classes of antibiotics. The evolution of antibiotic resistance in pneumococcus was influenced by changes in serotype distribution under vaccine selection pressure.. The aim of this study was to determine the genes involved in macrolide resistance, the antimicrobial susceptibility, the serotype distribution and the spread of international antibiotic-resistant clones among clinical isolates of .. We investigated 86 erythromycin-resistant strains isolated from respiratory (=74) or non-respiratory (=12) samples in Tunisia. Antimicrobial susceptibility was tested using the disk diffusion method. Macrolide-resistant strains were analysed by polymerase chain reaction (PCR) for , , and . We also investigated the macrolide resistance mechanisms in eight isolates (9.3%) by sequencing the L4 and L22 riboprotein-coding genes, plus relevant segments of the three 23S rRNA genes. Capsular serotypes were detected by multiplex PCR. Sequence types (STs) were explored using multilocus sequence typing (MLST).. Among the 86 studied strains, 70 (81.4 %) were resistant to penicillin G. The prevalent serotypes were 19F, 14, 19A and 23F. We observed that the cMLSB phenotype (66/86, 76.7%) was the most common in these pneumococci. In addition, was the most frequent resistance gene. No mutation in ribosomal protein L22 or L4 or 23S rRNA was detected. Overall, 44 STs were identified in this study, including 16 that were described for the first time. Resistance to lincomycin, tetracycline and trimethoprim/sulfamethoxazole was observed in 55 (64 %), 34 (39.5 %) and 31 (36 %) isolates, respectively. Furthermore, an increase in fluoroquinolone use in particular may lead to the emergence of levofloxacin-resistant strains. Multidrug resistance was observed in 83 isolates (96.5%). Three global antibiotic-resistant clones were identified: Denmark ST230, Portugal ST177 and Spain ST156.. This study shows that macrolide resistance among isolated in Tunisia is mainly related to target site modification. Our observations demonstrate a high degree of genetic diversity and capsular types among strains resistant to macrolides.
肺炎链球菌是许多社区感染的罪魁祸首，主要为肺炎和脑膜炎。肺炎链球菌对多种类别的抗生素产生了耐药性。肺炎链球菌抗生素耐药性的演变受到疫苗选择压力下血清型分布变化的影响。本研究旨在确定参与大环内酯类耐药的基因、抗菌药物敏感性、血清型分布以及国际抗生素耐药克隆在突尼斯临床分离株中的传播情况。我们调查了 86 株从突尼斯呼吸道（=74）或非呼吸道（=12）样本中分离的红霉素耐药菌株。采用纸片扩散法检测抗菌药物敏感性。聚合酶链反应（PCR）分析大环内酯类耐药菌株的 、 、 和 。我们还通过测序 L4 和 L22 核糖体蛋白编码基因以及三个 23S rRNA 基因的相关片段，在 8 株（9.3%）分离株中研究了大环内酯类耐药机制。通过多重 PCR 检测荚膜血清型。采用多位点序列分型（MLST）研究序列型（ST）。在研究的 86 株菌株中，70 株（81.4%）对青霉素 G 耐药。主要血清型为 19F、14、19A 和 23F。我们观察到这些肺炎链球菌中 cMLSB 表型（66/86，76.7%）最为常见。此外， 是最常见的耐药基因。未检测到核糖体蛋白 L22 或 L4 或 23S rRNA 突变。本研究共鉴定出 44 种 ST，其中 16 种为首次描述。55 株（64%）、34 株（39.5%）和 31 株（36%）分离株对林可霉素、四环素和复方磺胺甲噁唑耐药。此外，特别是氟喹诺酮类药物的使用增加可能导致左氧氟沙星耐药株的出现。83 株（96.5%）分离株表现出多重耐药性。鉴定出 3 种全球抗生素耐药克隆：丹麦 ST230、葡萄牙 ST177 和西班牙 ST156。本研究表明，突尼斯分离的 株对大环内酯类药物的耐药性主要与靶位修饰有关。我们的观察结果表明，对大环内酯类耐药的菌株具有高度的遗传多样性和荚膜型。
