1Department of Clinical Laboratory, Weifang People's Hospital, Weifang, Shandong, China.
2Department of ICU, Weifang People's Hospital, Weifang, Shandong, China.
Acta Microbiol Immunol Hung. 2024 Sep 3;71(3):220-227. doi: 10.1556/030.2024.02347. Print 2024 Sep 18.
This study examined the prevalence and antibiotic resistance pattern of blaCTX-M extended-spectrum β-lactamase positive Salmonella species isolated from a hospital in Weifang. Salmonella strains were isolated from hospitalized patients from January 2018 to April 2023. Whole-genome sequencing was performed by Illumina platform. CTX-M-producing Salmonella were identified by Comprehensive Antibiotic Research Database (CARD). Strain susceptibility to six antimicrobial agents was assessed by BD Phoenix™ M50 System. MLST analysis confirmed sequence types and additionally, serotypes were determined by SeqSero2. Genetic environments of blaCTX-M genes were analyzed by Isfinder and BLASTn. Single nucleotide polymorphisms were used to construct a phylogenetic tree to analyze homology. A total of 34 CTX-M-producing Salmonella were detected. The most prevalent serotype was Salmonella enterica subsp. enterica 1,4,[5],12:i:- (14/34, 41.18%), belonging to ST34, followed by Salmonella Enteritidis (10/34, 29.41%), belonging to ST11. The highest resistance rate was detected to ampicillin (97.06%), followed by ceftriaxone (94.12%) and ceftazidime (58.83%). In CTX-M-producing Salmonella five types of blaCTX-M genes were identified, the most prevalent was blaCTX-M-55 (47.06%, 16/34), followed by blaCTX-M-14, blaCTX-M-65, blaCTX-M-125, and blaCTX-M-27 at 26.47% (9/34), 11.77% (4/34), 8.82% (3/34), and 5.88% (2/34), respectively. Apart from blaCTX-M, 40 antibiotic resistance genes were also detected, conveying resistance to multiple drugs and the most frequent genes were namely, mcr-1.1, aph(6)-Id, aph(3″)-Ib, oqxAB, qnrB6, qnrS1. According to genetic environment analysis, the insertion sequence ISEcp1 was prevalent upstream of the blaCTX-M gene. Our study demonstrates that multiple resistance genes are carried by clinical isolates of Salmonella spp. however, the dominant ESBL genotype is CTX-M-55, that is associated with ISEcp1.
本研究调查了从潍坊一家医院分离的 blaCTX-M 型扩展谱β-内酰胺酶阳性沙门氏菌属的流行情况和抗生素耐药模式。沙门氏菌株从 2018 年 1 月至 2023 年 4 月住院患者中分离得到。采用 Illumina 平台进行全基因组测序。通过 Comprehensive Antibiotic Research Database (CARD) 鉴定产 CTX-M 的沙门氏菌。采用 BD Phoenix™ M50 系统评估菌株对 6 种抗菌药物的敏感性。MLST 分析确认序列类型，另外通过 SeqSero2 确定血清型。采用 Isfinder 和 BLASTn 分析 blaCTX-M 基因的遗传环境。单核苷酸多态性用于构建系统发育树以分析同源性。共检测到 34 株产 CTX-M 的沙门氏菌。最常见的血清型是肠炎沙门氏菌亚种。肠沙门氏菌 1,4,[5],12:i:-（14/34，41.18%），属于 ST34，其次是肠炎沙门氏菌（10/34，29.41%），属于 ST11。对氨苄西林的耐药率最高（97.06%），其次是头孢曲松（94.12%）和头孢他啶（58.83%）。在产 CTX-M 的沙门氏菌中，鉴定出 5 种 blaCTX-M 基因，最常见的是 blaCTX-M-55（47.06%，16/34），其次是 blaCTX-M-14、blaCTX-M-65、blaCTX-M-125 和 blaCTX-M-27，分别占 26.47%（9/34）、11.77%（4/34）、8.82%（3/34）和 5.88%（2/34）。除了 blaCTX-M 外，还检测到 40 种抗生素耐药基因，对多种药物产生耐药性，最常见的基因是 mcr-1.1、aph(6)-Id、aph(3″)-Ib、oqxAB、qnrB6 和 qnrS1。根据遗传环境分析，blaCTX-M 基因上游普遍存在插入序列 ISEcp1。本研究表明，临床分离的沙门氏菌携带多种耐药基因，但主要的 ESBL 基因型是 CTX-M-55，与 ISEcp1 相关。
