Department of Microbiology, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran.
Evidence-based Phytotherapy and Complementary Medicine Research Center, Alborz University of Medical Sciences, Karaj, Iran.
Ann Clin Microbiol Antimicrob. 2023 May 6;22(1):34. doi: 10.1186/s12941-023-00589-9.
Carbapenem-resistant Acinetobacter baumannii (CRAB) is a global health crisis. This study aimed to determine the clonal relatedness of antibiotic-resistant A. baumannii isolates in hospitalized patients who suffered from burn wound infection.
One hundred and six A. baumannii isolates from 562 patients with burn wound infections, were identified and examined for antimicrobial susceptibility. Detection and characterization of carbapenem-hydrolyzing class D OXA-type beta-lactamases (CHDLs) were performed by PCR assays. The clonal relatedness of A. baumannii isolates was determined by multilocus sequence typing (MLST) according to the Pasteur scheme, dual-sequence typing of bla-like and ampC genes, and RAPD-PCR method.
All isolates were carbapenem-resistant while susceptible to colistin, minocycline, doxycycline, and ampicillin-sulbactam. The intrinsic bla-like was detected in all isolates, and bla-like was identified in 92.5% of isolates. However, bla-like and bla-like genes were not detected among isolates. Four distinct bla-like alleles were determined as follows: bla (67.0%), bla (9.4%), bla (17.0%), and bla (6.6%) and four ampC (bla) allele types including ampC-25 (6.6%), ampC-39 (9.4%), ampC-1 (17.0%), and bla (67.0%) were identified. MLST (Pasteur scheme) analysis revealed four ST types including ST136 (singleton), ST1 (CC1), ST25 (CC25), and ST78 (singleton) in 71, 18, 7, and 10 of A. baumannii strains, respectively. Five RAPD clusters including A (1.9%), B (26.4%), C (57.5%), D (7.5%), and E (1.9%) were characterized and 5 (4.7%) strains were found to be singletons.
The present study demonstrated that there was a high prevalence of bla-like producing CRAB in the clinical setting. The majority of isolates belonged to ST136 (singleton). However, bla-like producing multi-drug resistant international clones including ST1, and emerging lineages (e.g. ST25 and ST78) were also identified. Interestingly, in this study ST2 was not detected.
耐碳青霉烯鲍曼不动杆菌（CRAB）是全球健康危机。本研究旨在确定住院烧伤患者感染创面分离的抗生素耐药鲍曼不动杆菌的克隆相关性。
从 562 例烧伤创面感染患者中分离出 106 株鲍曼不动杆菌进行鉴定和药敏试验。采用 PCR 法检测碳青霉烯水解类 D 型 OXA 型β-内酰胺酶（CHDLs）的检测和特征。根据巴斯德方案、bla 样和 ampC 基因的双重序列分型以及 RAPD-PCR 方法，采用多位点序列分型（MLST）确定鲍曼不动杆菌分离株的克隆相关性。
所有分离株均对碳青霉烯类药物耐药，但对多粘菌素、米诺环素、强力霉素和氨苄西林-舒巴坦敏感。所有分离株均检测到固有 bla 样，92.5%的分离株检测到 bla 样。然而，bla 样和 bla 样基因在分离株中未被检测到。确定了 4 种不同的 bla 样等位基因，分别为 bla（67.0%）、bla（9.4%）、bla（17.0%）和 bla（6.6%），4 种 ampC（bla）等位基因类型分别为 ampC-25（6.6%）、ampC-39（9.4%）、ampC-1（17.0%）和 bla（67.0%）。MLST（巴斯德方案）分析显示，71、18、7 和 10 株鲍曼不动杆菌分别为 ST136（单克隆）、ST1（CC1）、ST25（CC25）和 ST78（单克隆）。鉴定出 5 个 RAPD 聚类，包括 A（1.9%）、B（26.4%）、C（57.5%）、D（7.5%）和 E（1.9%），其中 5 株（4.7%）为单克隆。
本研究表明，临床环境中存在高产 bla 样的耐碳青霉烯鲍曼不动杆菌，大多数分离株属于 ST136（单克隆）。然而，也鉴定出了包括 ST1 在内的多药耐药国际克隆和新兴谱系（如 ST25 和 ST78）。有趣的是，在本研究中未检测到 ST2。
