Background: The global emergence of plasmid-mediated colistin resistance (Col-R) conferred by mcr genes in gram-negative rods (GNRs) has jeopardized the last treatment option for multidrug-resistant bacterial infections in humans. This study aimed to assess the emergence of mcr gene-mediated Col-R in GNRs isolated from humans and animals in Pakistan. Methods: Animal and clinical specimens collected from various sources were prospectively analysed using standard microbiological procedures. Pathogens were identified using the API 20E and API 20NE systems (bioMerieux). Minimum inhibitory concentration (MIC) against colistin was determined using the MIC detection methods, and multiplex polymerase chain reaction (PCR) was used to amplify the mcr-1 to mcr-5 genes. Results: We isolated 126 (88.1%) animal and 17 (11.9%) human Col-R phenotypes, among which there was a significant association (P < 0.01) of Escherichia coli and Proteus mirabilis with animals and of Acinetobacter baumannii with humans. Animal strains exhibited statistically significant (P < 0.05) resistance to co-trimoxazole, chloramphenicol, and moxifloxacin, and the human pathogens exhibited statistically significant (P < 0.05) antibiotic resistance to cephalosporins, carbapenems, and piperacillin-tazobactam. For Col-R strains, MIC₅₀ values were > 6 µg/mL and > 12 µg/mL for human and animal isolates, respectively. mcr genes were detected in 110 (76.9%) bacterial strains, of which 108 (98.2%) were mcr-1 and 2 (1.8%) were mcr-2. Conclusions: The detection of a considerable number of mcr-1 and mcr-2 genes in animals is worrisome, as they are now being detected in clinical pathogens. The acquisition of mcr genes by colistin-susceptible bacteria could leave us in a post-antibiotic era.

Objective: The objective of this study was to determine the occurrence and antimicrobial profile of AmpC ?-lactamase producing bacteria.Methods: The study was conducted at The Children

Background: The emergence of AmpC beta-lactamase producing Enterobacter cloacae becomes a serious nosocomial menace due to wider resistance. The study aimed to know the existence of these superbugs in the hospital settings and to report the current trends in their antibiotic resistance. Methods: We chose a tertiary care pediatric hospital for this cross-sectional study and processed 27,000 clinical specimens for the isolation of E. cloacae using routine microbiological procedures. A total number of 96 E. cloacae isolates from various sources were screened for AmpC production with cefoxitin (30 μg) and confirmed by inhibitor based technique. The antibacterial drug resistance studied against various groups of antibiotics in vitro. Results : Boronic acid inhibitor based method revealed 63 (65.6%) pathogens as AmpC beta-lactamase producing E. cloacae. Most of the infected patients with AmpC producing E. cloacae were neonates (34; 54.0%) and infants (11; 17.5%). The primary source of AmpC producing E. cloacae was blood (43; 68.3%), and they were frequently distributed in the neonatal nursery unit (33; 52.4%) and medical ward (13; 20.6%). All of these bugs showed a high level of resistance (100%) against the co-amoxiclav and cephalosporin group.The organisms exhibited less resistance to levofloxacin, imipenem and colistin sulphate as 23 (36.5%), 20 (31.7%) and 17 (27.0%), respectively. Conclusion: The consistent emerging threat of Amp C harbouring E. cloacae could disseminate AmpC genes in other genera of the bacteria which lead to the therapeutic failure and leave the doctors with limited treatment options of levofloxacin, imipenem and colistin sulphate. Bangladesh Journal of Medical Science Vol.19(4) 2020 p.632-637