Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Department of Microbiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
BMC Infect Dis. 2024 Oct 7;24(1):1117. doi: 10.1186/s12879-024-10018-7.
This study aims to investigate the frequency of cas1 and cas3 and CRISPR1,2,3 genes in Klebsiella pneumoniae isolates, as well as their connection with antibiotic resistance.
106 K. pneumoniae isolates were identified by biochemical assays and PCR. The susceptibility to antibiotics was determined by Kirby-Bauer disk diffusion method. Screening of ESBLs was undertaken by using double disk diffusion and standard disk diffusion methods. The E-test and mCIM techniques was used to confirm the disc diffusion-based carbapenem resistance profiles. CRISPR-Cas system genes were identified using PCR.
ESBL production was found in 19% of isolates. Carbapenemase production was found in 46% of the isolates. Furthermore, the bacteria were classified as multidrug (76%), extensively drug-resistant (4%), or pan-drug-resistant (2%). When CRISPR/Cas systems were present, antibiotic resistance was lower; conversely, when they were absent, resistance was higher.
If the CRISPR/Cas modules aren't present, the bacteria can still acquire foreign DNA, including antibiotic resistance genes. K. pneumoniae isolates with a CRISPR-Cas system were less likely to carry antibiotic-resistance genes than those lacking this defense system.
本研究旨在调查肺炎克雷伯菌分离株中 cas1 和 cas3 以及 CRISPR1、2、3 基因的频率，以及它们与抗生素耐药性的关系。
通过生化试验和 PCR 鉴定 106 株肺炎克雷伯菌。采用 Kirby-Bauer 纸片扩散法测定抗生素敏感性。采用双纸片扩散和标准纸片扩散法筛选 ESBLs。使用 E 试验和 mCIM 技术确认基于纸片扩散的碳青霉烯类耐药表型。采用 PCR 鉴定 CRISPR-Cas 系统基因。
19%的分离株产生 ESBL。46%的分离株产生碳青霉烯酶。此外，细菌被分类为多药耐药（76%）、广泛耐药（4%）或全耐药（2%）。当存在 CRISPR/Cas 系统时，抗生素耐药性较低；相反，当不存在时，耐药性较高。
如果不存在 CRISPR/Cas 模块，细菌仍然可以获得包括抗生素耐药基因在内的外源 DNA。与缺乏这种防御系统的菌株相比，携带 CRISPR-Cas 系统的肺炎克雷伯菌分离株携带抗生素耐药基因的可能性较小。
