[Molecular epidemiology and antibiotic resistance of Pseudomonas aeruginosa isolated from blood in a hospital in Shandong Province from 2014 to 2021].

Objective: To identify the antibiotic resistance, virulence genes, and sequence types of Pseudomonas aeruginosa (P. aeruginosa) strains isolated from blood. Methods: From November 2014 to December 2021, a total of 94 nonrepetitive P. aeruginosa isolates were obtained from blood samples of patients at the First Affiliated Hospital of Shandong First Medical University in Shandong Province, China. The bacteria were identified using matrix-assisted laser desorption ionization time of flight mass spectrometry. Antibiotic resistance of the P. aeruginosa isolates was detected using Vitek 2 Compact system. Polymerase chain reaction (PCR) was conducted for the 18 virulence genes, and multi locus sequence typing (MLST) was performed to identify the sequence types of the P. aeruginosa strains. The resistance rates and distributions of virulence genes between carbapenem resistant pseudomonas aeruginosa (CRPA) and carbapenem susceptible pseudomonas aeruginosa (CSPA) isolates were compared using the Chi-square test. Results: Among 94 P. aeruginosa isolates, 19 (20.2%) isolates were found to be multidrug resistant (MDR) bacteria, of which 17 were CRPA isolates and 2 were CSPA isolates. All strains contained more than 10 virulence genes. Except for exoU gene, the detection rate of other genes was above 83%. MLST analysis revealed a total of 66 different STs, including 59 existing STs and 7 novel STs. Among them, ST244 (n=11, 11.7%) and ST270 (n=7, 7.4%) were the dominant STs. Although these two types of isolates harbored the same virulence genes, the resistance rates to carbapenem were different. 54.5% (6/11) ST244 isolates were CRPA but all 7 ST270 isolates were CSPA. Conclusion: Although the resistance rates of P. aeruginosa strains isolated from blood were at a low level, some MDR and CRPA isolates were detected. As the high virulence gene detection rates and genetic diversity were found for P. aeruginosa strains isolated from blood, close attention should be paid to avoid transmission and outbreaks.目的： 探讨引起血流感染铜绿假单胞菌（Pseudomonas aeruginosa，P. aeruginosa）的耐药性、毒力基因携带情况以及多位点序列分型（MLST）的型别。 方法： 回顾性收集2014年11月至2021年12月山东第一医科大学第一附属医院引起血流感染的铜绿假单胞菌94株。使用基质辅助激光解析/电离飞行时间质谱仪对铜绿假单胞菌进行菌种鉴定，使用Vitek 2 Compact 全自动细菌药敏分析系统对铜绿假单胞菌进行抗菌药物敏感性实验。应用聚合酶链式反应（PCR）方法对18种常见毒力基因的携带情况进行检测。应用MLST对分离菌株进行分型。采用卡方检验对碳青霉烯类抗生素耐药的铜绿假单胞菌（carbapenem resistant pseudomonas aeruginosa，CRPA）和碳青霉烯类抗生素敏感的铜绿假单胞菌（carbapenem susceptible pseudomonas aeruginosa，CSPA）菌株的耐药及毒力基因的携带情况进行比较。 结果： 在94株铜绿假单胞菌中，有19株（20.2%）为多重耐药（MDR）菌株，其中有17株为碳青霉烯类抗菌药物耐药株，2株为碳青霉烯类抗菌药物敏感株。所有菌株均包含10种以上的毒力基因，除exoU基因外，其余基因的检出率均在83%以上。本研究共发现66个ST型，包括59个已知ST型和7个新ST型。其中ST244（11株，11.7%）和ST270（7株，7.4%）为优势型别，两种型别的菌株具有相同的毒力基因分布，但对碳青霉烯类抗菌药物的耐药率有所差异，其中ST244型别的菌株中有54.5%（6株）的为CRPA，但7株ST270型别的菌株则均为CSPA。 结论： 引起血流感染铜绿假单胞菌的耐药性处于较低水平，但存在一定数量的碳青霉烯类抗菌药物耐药菌株和多重耐药菌株。这些菌株具有较高毒力基因携带率和分子多态性特征，在临床上应予以关注。.