Prevalence of NDM-1 metallo-β-lactamase-producing Brevundimonas diminuta/vesicularis isolated from bloodstream infections in Iraq

Background and aim: Brevundimonas spp. are ubiquitous in the environment, but they are infrequently isolated from clinical specimens. Brevundimonas spp. cause bacteremia and sepsis, less frequently pneumonia, which resist numerous antibiotics, such as fluoroquinolone and beta lactams. The aim of this study was to investigate the epidemiological distribution of the NDM-1 gene in metallo-β-lactamase-producing Brevundimonas diminuta/vesicularis clinical isolates from pediatric patients with bloodstream infections. Methods: Totally, 384 blood samples were collected from children aged ≤10 years old attended Baghdad hospital children, Baghdad, Iraq. The blood samples were screened for bacterial species by cultural, biochemical methods and Vitek-2 system. Nine isolates were confirmed to be Brevundimonas diminuta/vesicularis had been selected to be screened for antimicrobial susceptibility, extended-spectrum β-lactamase (EsβL) production and Molecular characterization of antibiotic resistance genes ( bla NDM-1 , bla SHV , IMP-1 , aac(6’)-Ib- , qnrB , and VIM ). Results: Totally, 382 pure isolates were obtained in this study belonging to different 48 bacterial species. The highest occurrence was for Escherichia coli (55 isolates), followed by Klebsiella pneumonia (44 isolates), and 9 isolates were identified as Brevundimonas diminuta/vesicularis . From antimicrobial susceptibility test to the isolated Brevundimonas diminuta/vesicularis strains, two isolates were resistant to Imipenem, one isolate was resistant to eight antibiotics from three different classes of antibiotics and considered as multidrug resistant strains. Also, four isolates gave positive results in the screening of βL. The results of molecular assay of resistance genes was variable thus, two isolates have blaNDM-1 gene, one isolate was positive for IMP-1 gene, three isolates were positive for VIM gene, five isolates were positive for blaSHV gene, two isolates were positive for qnrB gene and one isolate was positive for aac(6’)-Ib gene. Conclusions: Carbapenem-resistant Gram-negative bacteria are a major public health threat, and Brevundimonas diminuta/vesicularis is an emerging pathogen that can be particularly resistant to these antibiotics. So, the fact that this is the first report about the clonal diversity of these isolates from blood in Baghdad. Overall, this study is an important contribution to our understanding of carbapenem resistance in Iraq. It sheds light on a previously understudied pathogen and could have significant implications for patient care in the region.