Epidemiology, Molecular Characteristics, and Virulence Factors of Carbapenem-Resistant Pseudomonas aeruginosa Isolated from Patients with Urinary Tract Infections

Abstract

Purpose

Pseudomonas aeruginosa is an important pathogen that causes urinary tract infections. Carbapenems are the drugs of choice for the treatment of P. aeruginosa infections. However, the emergence and spread of carbapenem-resistant P. aeruginosa (CRPA) is a serious global health threat. In this study, we investigated the epidemiology, molecular characteristics, drug resistance, and virulence factors of CRPA isolated from urine samples.

Methods

A total of 124 P. aeruginosa isolates were obtained from urine samples collected between March 2020 and February 2021. Clonal relatedness was evaluated using multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). We performed antimicrobial susceptibility tests and investigated the presence of carbapenemase genes and virulence factors in CRPA isolates.

Results

The carbapenem resistance rate of the isolated P. aeruginosa was 46.7% (59/124). A total of 54 (91.5%) out of the 59 CRPA isolates were identified as multidrug-resistant. The majority of the CRPA isolates (81.4%, 48/59) harbored carbapenemase genes, such as bla_IMP-6 or bla_NDM-1. In an epidemiological analysis using MLST, 88.1% of CRPA isolates were confirmed to be ST773 (50.8%, 30/59) or ST235 (37.3%, 22/59). The CRPA isolates harboring bla_IMP-6 and bla_NDM-1 belonged to ST235 (PFGE pulsotypes E1-E18, F) and ST773 (PFGE pulsotypes H1-H2, I1-I16) subtypes, respectively. The studied CRPA isolates simultaneously harbored 10 to 14 virulence factors of the 16 virulence factors examined. Nine virulence factor genes (toxA, exoT, plcH, plcN, phzM, phzS, lasB, aprA, and algD) were identified in all CRPA isolates.

Conclusion

Our study shows that P. aeruginosa ST235 harboring bla_IMP-6 and ST773 harboring bla_NDM-1—known internationally as high-risk clones with multiple virulence factors—are widely spread in the study area. These findings suggest that continuous monitoring is necessary to prevent the further spread of carbapenemase-producing CRPA.

Keywords:

• carbapenem resistance
• metallo-β-lactamase
• virulence factor
• urinary tract infection

Abbreviations

BLAST, Basic Local Alignment Search Tool; CFU, colony forming units; CRPA, carbapenem-resistant P. aeruginosa; ETA, exotoxin A; IMP, imipenemase; PCR, polymerase chain reaction; MBL, metallo-β-lactamase; MDR, multidrug resistance; MIC, minimum inhibitory concentration; MLST, multilocus sequence typing; NCBI, National Center for Biotechnology Information; NDM, New Delhi metallo-β-lactamase; PFGE, pulsed-field gel electrophoresis; STs, sequence types; T3SS, type III secretion system; UTI, urinary tract infection; VIM, Verona Integron-encoded Metallo-β-lactamase.

Ethics Approval and Informed Consent

The study was reviewed and approved by the Ethical Review Committee of the Konyang University Hospital (No. NON2021-001). The ethical review committee of Konyang University Hospital waived the requirement for informed consent. The retrospective study was considered exempt from the ethical review because only bacterial isolates were taken from patients and patient confidentiality was fully guaranteed. This study was conducted in accordance with the principles of the Declaration of Helsinki.

Consent for Publication

All authors approved the manuscript and gave their consent for submission and publication.

Author Contributions

All authors contributed to data analysis, drafting or revising the article, have agreed on the journal to which the article will be submitted, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that there are no conflicts of interest regarding the publication of this article.

Additional information

Funding

This work was supported by the Research Resettlement Fund for the new faculty of Konyang University Hospital.