1. Academic Validation
  2. Plasmid-Borne AFM Alleles in Pseudomonas aeruginosa Clinical Isolates from China

Plasmid-Borne AFM Alleles in Pseudomonas aeruginosa Clinical Isolates from China

  • Microbiol Spectr. 2022 Aug 24;e0203522. doi: 10.1128/spectrum.02035-22.
Minhua Chen  # 1 Heng Cai  # 2 3 4 Yue Li 2 3 4 Nanfei Wang 2 3 4 Piaopiao Zhang 2 3 4 Xiaoting Hua 2 3 4 Yunsong Yu 2 3 4 Renhua Sun 1
Affiliations

Affiliations

  • 1 Emergency and Critical Care Center, Intensive Care Unit, Zhejiang Provincial People's Hospital (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou, Zhejiang, People's Republic of China.
  • 2 Department of Infectious Diseases, Sir Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.
  • 3 Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, People's Republic of China.
  • 4 Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China.
  • # Contributed equally.
Abstract

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a pathogen of global concern due to the fact that therapeutic drugs are limited. Metallo-β-lactamase (MBL)-producing P. aeruginosa has become a critical part of CRPA. Alcaligenes faecalis Metallo-β-lactamase (AFM) is a newly identified subclass B1b MBL. In this study, 487 P. aeruginosa strains isolated from patients and the environment in an intensive care unit were screened for AFM alleles. Five AFM-producing strains were identified, including four AFM-2-producing strains (ST262) and one AFM-4-producing strain (ST671). AFM-2-producing strains were isolated from rectal and throat swabs, and AFM-4-producing strains were isolated from the water sink. The blaAFM-2 carrying plasmids belonged to the IncP-2 type, while the blaAFM-4 carrying plasmid pAR19438 was a pSTY-like megaplasmid. Plasmid pAR19438 was acquired blaAFM-4 by the integration of the Tn1403-like transposon. All blaAFM genes were embedded in an ISCR29-blaAFM unit core module flanked by class 1 integrons. The core module of blaAFM-2 was ISCR29groL-blaAFM-2-bleMBLtrpF-ΔISCR, while the core module of blaAFM-4 was ISCR29groL-blaAFM-2-bleMBLtrpF-ISCR-msrB-msrA-yfcG-corA-ΔISCR. The flanking sequences of ISCR29-blaAFM units also differed. The expression of AFM-2 and AFM-4 in DH5α and PAO1 illustrated the same effect for the evaluation of the MICs of β-lactams, except for aztreonam. Identification of AFM-4 underscores that the quick spread and emerging development of mutants of MBLs require continuous surveillance in P. aeruginosa. IMPORTANCE Acquiring Metallo-β-lactamase genes is one of the important carbapenem resistance mechanisms of P. aeruginosa. Alcaligenes faecalis Metallo-β-lactamase is a newly identified Metallo-β-lactamase, the prevalence and genetic context of which need to be explored. In this study, we identified AFM-producing P. aeruginosa strains among clinical isolates and found a new mutant of AFM, AFM-4. The blaAFM-4 carrying plasmid pAR19438 was a pSTY-like megaplasmid, unlike the plasmids encoding other blaAFM alleles. The genetic context of blaAFM-4 was also different. However, AFM-2 and AFM-4 had the same impacts on Antibiotic susceptibility. The presence and transmission of AFM alleles in P. aeruginosa pose a challenge to clinical practice.

Keywords

AFM-2; AFM-4; Pseudomonas aeruginosa; metallo-β-lactamase; plasmid.

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