AUTHOR=Lin Hailong , Feng Chunlin , Zhu Tingting , Li Anqi , Liu Shuang , Zhang Lei , Li Qiaoling , Zhang Xueya , Lin Li , Lu Junwan , Lin Xi , Li Kewei , Zhang Hailin , Xu Teng , Li Changchong , Bao Qiyu 

TITLE=Molecular Mechanism of the β-Lactamase Mediated β-Lactam Antibiotic Resistance of Pseudomonas aeruginosa Isolated From a Chinese Teaching Hospital

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.855961

DOI=10.3389/fmicb.2022.855961

ISSN=1664-302X

ABSTRACT=<p><italic>Pseudomonas aeruginosa</italic> can cause infections in the blood, lungs (pneumonia), or other parts of the body after surgery. To investigate the molecular characteristics of β-lactam antibiotic resistance of <italic>P. aeruginosa</italic> isolated from a hospital population between 2015 and 2017, in this study, the antimicrobial susceptibility and the resistance gene profile of the bacteria were determined. The Pulsed-field gel electrophoresis (PFGE) was used to characterize the clonal relatedness and sequencing and comparative genomic analysis were performed to analyze the structure of the resistance gene-related sequences. As a result, of the 260 <italic>P</italic>. <italic>aeruginosa</italic> strains analyzed, the resistance rates for 6 β-lactam antibiotics ranged from 4.6 to 9.6%. A total of 7 genotypes of 44 β-lactamase genes were identified in 23 isolates (8.9%, 23/260). Four transconjugants from different donors carrying <italic>bla</italic><sub>CARB-3</sub> exhibited a phenotype of reduced susceptibility to piperacillin–tazobactam, ceftazidime, and cefepime, and 2 transconjugants harboring <italic>bla</italic><sub>IMP-45</sub> exhibited a phenotype of reduced susceptibility to carbapenems. <italic>bla</italic><sub>CARB</sub> positive isolates (<italic>n</italic> = 12) presented six PFGE patterns, designated groups A to F. Two <italic>bla</italic> genes (<italic>bla</italic><sub>IMP-45</sub> and <italic>bla</italic><sub>OXA-1</sub>) in PA1609 related to a class 1 integron (<italic>intI1</italic>-<italic>bla</italic><sub>IMP-45-</sub><italic>bla</italic><sub>OXA-1</sub>-<italic>aac(6′)-Ib7</italic>-<italic>catB3</italic>-<italic>qacE∆1</italic>-<italic>sul1</italic>) were encoded on a plasmid (pPA1609-475), while the <italic>bla</italic><sub>CARB-3</sub> gene of PA1616 also related to a class 1 integron was located on the chromosome. The results suggest that β-lactam antibiotic resistance and clonal dissemination exist in this hospital population. It indicates the necessity for molecular surveillance in tracking β-lactamase-producing strains and emphasizes the need for epidemiological monitoring.</p>