Occurrence of Metallo-β-lactamase Variants Among Heterogeneous Population of Carbapenem Resistant Clinical Pseudomonas aeruginosa from Savar, Bangladesh

Background and Objectives: Worldwide dissemination of Metallo-β-Lactamases (MBLs) has been reported as a major mechanism of resistance to carbapenems in clinical Gram-negative isolates, including Pseudomonas aeruginosa (P. aeruginosa). The present study aimed to investigate the occurrence of MBL variants in carbapenem resistant P. aeruginosa isolates from Dhaka, Bangladesh. Methods: Samples from patients (n=۲۳۸) with urinary tract infections, wound infections, and catheter-associated infections from two academic hospitals of Savar, Dhaka were investigated. Carbapenem susceptibility of the isolates was tested against imipenem and meropenem. MBL-mediated carbapenem resistance was investigated phenotypically and through PCR amplification of four MBL variants. Plasmid extraction was conducted to observe association with MBL carriage. ERIC-PCR was carried out to determine possible epidemiological linkages. Results: The presence of P. aeruginosa was detected in ۲۲% (۵۳/۲۳۸) of the collected clinical samples. Resistance to carbapenems was present among ۳۰% (۱۶/۵۳) of these clinical isolates, which is more than ۲-fold higher compared to that of previous studies. Phenotypic expression of MBL was detected in ۹۰% (۱۴/۱۶) of resistant isolates. Molecular analysis revealed that ۶۳% (۱۰/۱۶) of the carbapenem-resistant isolates carried at least one of the MBL variants, either bla-VIM or bla-NDM-۱. All positive bla-NDM-۱ variants carried a ۰.۵ MDa plasmid. ERIC-PCR revealed highly heterogeneous nature of P. aeruginosa isolates indicating multiple sources of infection within the hospital. Conclusion: These findings indicate an increased MBL-mediated resistance to carbapenem in P. aeruginosa, which poses a serious threat to the treatment of infections among hospitalized patients.

کلیدواژه ها:

Carbapenem-resistance ، Genetic Variants ، Metallo-β-lactamase ، Nosocomial Infection ، Pseudomonas aeruginosa ، مقاومت به کارباپنم ، واریانت های ژنتیکی ، متالو بتالاکتاماز ، عفونت بیمارستانی ، سودوموناس آئروژینوزا