Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan, Iran.
Department of Microbiology, Faculty of Medicine, Golestan University of Medical Sciences, P.O. Box: 4934174515, Gorgan, Iran.
Int Microbiol. 2022 Nov;25(4):709-721. doi: 10.1007/s10123-022-00256-7. Epub 2022 Jun 14.
Pseudomonas aeruginosa is an important nosocomial pathogen with a capacity of resistance to multiple antibiotics and production of various extracellular and cell-associated virulence factors that clearly contribute to its pathogenicity. The objective of this study was to investigate the antibiotic susceptibility, virulence factors, and clonal relationship among clinical isolates of P. aeruginosa. Different clinical specimens from hospitalized patients were investigated for P. aeruginosa. Susceptibility of the isolates was evaluated by disc diffusion and broth microdilution methods, as described by the Clinical and Laboratory Standards Institute (CLSI) guideline. A total of 97 P. aeruginosa isolates were recovered from clinical specimens. The percentage of isolates resistant to antimicrobials was imipenem 25.77%, meropenem 15.46%, gentamicin 16.49%, tobramycin 15.46%, amikacin 16.49%, ciprofloxacin 20.61%, levofloxacin 24.74, ceftazidime 20.61%, piperacillin 15.46%, piperacillin/tazobactam 12.37%, colistin 9.27%, and polymyxin B 11.34%. Of isolates, 87.62% possessed β-hemolytic activity, 78.35% lecithinase, 59.8% elastase, 37.11% DNase, and 28.86% twitching motility. The frequency of virulence genes in isolates was lasB 82.47%, plcH 82.47%, exoA 58.76%, exoS 56.7%, and pilA 10.3%. ERIC-PCR typing clustered P. aeruginosa isolates to 19 common types (CT1-CT19) containing isolates from different hospitals and 43 single types (ST1-ST43). Colistin and polymyxin B were the most effective agents against the majority of P. aeruginosa isolates, emphasizing the effort to maintain their antibacterial activity as last-line therapy. The frequency of some virulence factors and genes was noticeably high, which is alarming. In addition, more effective strategies and surveillance are necessary to confine and prevent the inter-hospital and/or intra-hospital dissemination of P. aeruginosa between therapeutic centers.
铜绿假单胞菌是一种重要的医院获得性病原体，具有多种抗生素耐药性和产生多种细胞外和细胞相关毒力因子的能力，这些毒力因子显然有助于其致病性。本研究的目的是研究临床分离株铜绿假单胞菌的抗生素敏感性、毒力因子和克隆关系。从住院患者的不同临床标本中检测到铜绿假单胞菌。采用 CLSI 指南所述的纸片扩散和肉汤微量稀释法评估分离株的药敏性。从临床标本中分离出 97 株铜绿假单胞菌。对各种抗生素的耐药率分别为亚胺培南 25.77%、美罗培南 15.46%、庆大霉素 16.49%、妥布霉素 15.46%、阿米卡星 16.49%、环丙沙星 20.61%、左氧氟沙星 24.74%、头孢他啶 20.61%、哌拉西林 15.46%、哌拉西林/他唑巴坦 12.37%、多粘菌素 B 9.27%和黏菌素 9.27%。87.62%的分离株具有β-溶血活性，78.35%具有卵磷脂酶活性，59.8%具有弹性蛋白酶活性，37.11%具有 DNA 酶活性，28.86%具有扭动运动性。在分离株中，lasB 基因的频率为 82.47%，plcH 基因的频率为 82.47%，exoA 基因的频率为 58.76%，exoS 基因的频率为 56.7%，pilA 基因的频率为 10.3%。ERIC-PCR 分型将铜绿假单胞菌分离株聚类为 19 种常见型（CT1-CT19），包含来自不同医院的分离株和 43 种单型（ST1-ST43）。多粘菌素 B 和黏菌素对大多数铜绿假单胞菌分离株最有效，强调要努力保持其抗菌活性作为最后一线治疗药物。一些毒力因子和基因的频率明显较高，令人警惕。此外，还需要采取更有效的策略和监测措施，以限制和防止铜绿假单胞菌在治疗中心之间的医院间和/或院内传播。
