In this study, we investigated the prevalence of aminoglycosides modifying enzymes (AMEs)-encoding genes, including aac(3′)-ΙΙ, ant(3′′)-Ι, aph(3′)-VΙ, and aac(6′)-Ιb-cr and their potential effect on the development of resistance to aminoglycosides and fluoroquinolones in clinical isolates of Klebsiella pneumoniae. According to the phenotypic and biochemical characteristics of 150 clinical samples, 50 (33%) isolates were identified as K. pneumoniae. These isolates were collected from different clinical sources, including urine (15, 30%), blood (12, 24%), sputum (9, 18%), wounds (9, 18%), and burns (5, 10%). The minimum inhibitory concentrations (MICs) assay revealed that the resistance values of isolates were 25 (50%) to gentamicin (≥16µg/ml), 21 (42%) to amikacin (≥64 µg/ml), 15 (30%) to ciprofloxacin (≥4 µg/ml), and 11 (22%) to levofloxacin (≥8 µg/ml). Genotypic detection revealed that aac(3′)-ΙΙ, aac(6′)-Ιb-cr, aph(3′)-VΙ, and ant(3′′)-Ι were found in 47 (94%), 38 (76%), 18 (36%), and 8 (16%) of K. pneumoniae isolates, respectively. The co-resistance pattern for both aminoglycosides and fluoroquinolones was detected in 14 (28%) isolates, of these 10 (71.4%) harbored aac(6′)-Ιb-cr. DNA sequencing for some isolates revealed the presence of point and frameshift mutations in the studied genes. Our study findings suggest that the presence of missense and frameshift mutations may contribute to the elevated resistance to amikacin and gentamicin. The increased prevalence of AMEs-encoding genes among K. pneumoniae isolates could contribute in reducing susceptibility to amikacin and gentamicin. The co-resistance pattern for aminoglycosides and fluoroquinolones was highly associated with the presence of the aac(6′)-Ιb-cr gene.
This study investigated the prevalence of oqxA and oqxB genes and their effective roles in the development of multidrug resistant (MDR) phenotype among clinical isolates of Klebsiella pneumoniae. Out of 150 clinical samples, 50 (33%) isolates were recognized as K. pneumoniae according to the morphological and biochemical properties. The minimum inhibitory concentrations (MICs) assay revealed that the resistance values of the isolates were 43 (86%) against ceftriaxone (4- ≥64 µg/ml), 42 (84%) against ceftazidime (16- ≥64 µg/ml), 41 (82%) against cefepime (≥16 µg/ml), 21 (42%) against ertapenem (≥8 µg/ml), 18 (36%) against imipenem (4- ≥16 µg/ml), 15 (30%) against ciprofloxacin (≥4 µg/ml), 11 (22%) against levofloxacin (≥8 µg/ml), 45 (90%) against nitrofurantoin (128- ≥512 µg/ml), 36 (72%) against trimethoprime-sulfamethoxazole (≥320 µg/ml), and 4 (8%) against tigecycline (≥8 µg/ml). Genotype detection revealed that oqxA was found in 48 (96%) of K. pneumoniae isolates, whereas oqxB was found in 6 (12%) isolates. The MDR phenotype was observed in 40 (80%) isolates, of which 38 (95%) were harbored oqxA and/or oqxB genes. DNA sequencing of oqxA revealed the presence of three silent mutations. The phylogenetic tree of oqxA variants showed a significant deviation of these variants from K. pneumoniae species. The high prevalence of oqxA among K. pneumoniae isolates may contribute to the reduction of their susceptibility to multiple antimicrobial agents.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.