Occurrence of intI1-associated VIM-5 carbapenemase and co-existence of all four classes of β-lactamase in carbapenem-resistant clinical Pseudomonas aeruginosa DMC-27b

Abstract

Objectives Emergence of carbapenem-resistant Pseudomonas aeruginosa is limiting current treatment options. Carbapenemases and their association with integrons can cause rapid dissemination of resistance traits. We report here the co-existence and chromosomal inheritance of all four classes of β-lactamase and the presence of a unique class 1 integron (intI1) harbouring blaVIM-5 within a single isolate of P. aeruginosa, DMC-27b. Methods DMC-27b, isolated from urine, was characterized for carbapenem resistance both phenotypically and genotypically. The orientation of gene cassette structures of class 1 integrons was determined using referenced and designed overlapping primers and complete genome sequence (CGS) data. The antimicrobial resistance profile, porin protein mutations and the presence of active efflux activity were studied from the CGS. Results P. aeruginosa DMC-27b was resistant to a total of 20 antibiotics, with imipenem and meropenem MIC90s of >512 mg/L. The isolate harboured all four classes of β-lactamase: VEB-1 (class A), VIM-5 (class B), PDC-35 (class C) and OXA-2 and OXA-50 (both class D). Chromosomal harbouring of blaVIM-5 was associated with the intI1 gene cassette as the sole gene, a unique cassette so far reported. A total of 11 mutations, among them some mutations causing extra folds and changes in binding sites, in porin protein OprD might also affect its functionality regarding the transportation of antibiotics. Conclusions This is one of the earliest reports of its kind on the co-existence of all four β-lactamase classes in P. aeruginosa DMC-27b. Acquisition of multiple resistance determinants is paving the way for the development of MDR. This superbug is a model for rapid dissemination of resistance traits both horizontally and vertically.

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

“…These strains showed a wider resistance spectrum and higher resistance levels to the β-lactam antibiotics tested in this study. Co-occurrence of β-lactamase genes displays high rates of resistance to broad-spectrum cephalosporins owing to induced expression of ampC β-lactamase gene, and an increasing number of organisms harboring plasmid-encoded extended-spectrum b-lactamase (ESBL) or/and carbapenemase genes have been described ( Jahan et al, 2020 ). Co-occurrence of β-lactamase genes has been reported worldwide.…”

Molecular Detection of Multidrug Resistant Salmonella Species Isolated from Broiler Farm in Bangladesh

“…Detection of mobile genetic elements, such as integron in these isolates make the situation more aggravated. Integrons are directly associated with resistance to antibiotics [50] and there are possibilities of their transmission to other bacterial species horizontally inside the broiler chicken gut. The present findings highlight the importance of practicing strict biosecurity, hygienic measures, proper litter management and safe storage of feed to reduce the load and spread of MDR Salmonella in broiler chicken and to ensure consumers' health and safety.…”

Genomic diversity and molecular epidemiology of a multidrug-resistant Pseudomonas aeruginosa DMC30b isolated from a hospitalized burn patient in Bangladesh

“…P. aeruginosa is one of the most common bacteria isolated from chronic wounds [6], and is highly prevalent in chronic wounds, estimated to be present in about 25% of all cases [7]. Infections caused by P. aeruginosa are usually difficult to treat and persistent due to the characteristic high frequency of emergence of MDR or extensively drug-resistant (XDR) strains [8][9][10]. The World Health Organization and Centers for Disease Control and Prevention have both designated P. aeruginosa as one of the major (critical) pathogens for which new antibiotics are desperately needed [11,12].…”