Antimicrobial Susceptibility and Plasmid Genes Conferring Multi-Drug Resistance among Klebsiella Pneumoniae Isolated from patients attending Mulago National Referral Hospital from 2017 to 2018.

Abstract

Introduction: Antimicrobial Resistance results from exposure of microorganisms to antimicrobial substances, consequently with the ineffectiveness of treatments and exacerbating the risk of spread to others. Klebsiella pneumoniae is one of the carbapenem-resistant, ESBL-producing Enterobacteriaceae listed among the Priority 1 critical pathogens in the world by 2017 WHO report on the global status of antibacterial resistance. The dissemination of antimicrobial resistance in numerous gram-negative bacteria has majorly been attributed to inter- and intra-specific DNA exchange by horizontal transfer of plasmid-located antimicrobial resistance genes. Plasmids are extra-chromosomal elements of DNA present in bacteria that replicate independently of the host genome. Methodology: This was a laboratory-based cross-sectional study in which the susceptibility profiles and conjugative genes of all the Multidrug-resistant Klebsiella pneumoniae isolates previously obtained from individuals attending Mulago National Referral Hospital were used. Recovery of stored isolates from January 2017 to December 2018 for re-identification by biochemical methods as Klebsiella pneumoniae, was performed. Susceptibility profiles of Klebsiella pneumoniae isolated in the selected study period were generated to determine Multi-Drug resistance by using the Kirby Bauer disc diffusion method. The Imipenem-EDTA double-disk synergy test was then performed to detect carbapenemase production. Conjugation experiments on L.B broth media using E. coli J53 as a recipient strain was done. Plasmid DNA from transconjugants was then extracted for PCR before gel Electrophoresis. Results: 63/67 of the test isolates were ESBL producers. Increasing resistance rates were observed, 83.3% of the MDR isolates were resistant to Ceftazidime, 99% to cefotaxime, 80.3% to amoxicillin-clavulanic acid and 84.9% to Cefepime. blaCTX-M was the most predominant gene in this setting although it was not readily disseminated by conjugation. A novel efflux pump in this setting OQX-AB was identified in 12/24 of the isolates tested that is responsible for multi-drug resistance. PCR detected the presence of blaTEM and QNR-s, blaTEM and OXA-1, blaTEM and aac(3)-IIa variants being disseminated by plasmids in combination from the same isolates after conjugation experiments. These isolates were majorly from patients admitted to the ICU of Mulago National Referral Hospital (71.4%). Conclusion: There was a high prevalence of plasmid associated conjugative genes in this setting specifically blaTEM, OXA-1, QEP, QNR-s, QNR-b and aac(3)-IIa gene. These findings elucidate the need for an active surveillance network for gram negative bacteria in Uganda.