Non-carbapenemase Producing Carbapenem-Resistant Klebsiella Pneumoniae Isolated from the Urinary Tract of a Dog

Objective Carbapenems are broad-spectrum beta-lactams with excellent activity against multidrug-resistant (MDR) Enterobacterales. Unfortunately, resistance to carbapenems within this bacterial family, known as carbapenemresistant Enterobacterales (CRE), occurs and challenges the ability to treat difficult MDR infections. Although the impact of carbapenem-resistance has been greatest in human medicine, reports in the veterinary literature are increasing especially as national veterinary antimicrobial resistance surveillance programs are now in place. In this brief communication, we report the isolation of a non-carbapenemase-producing, carbapenem-resistant Klebsiella pneumoniae from the urine of a dog, discuss the likely mechanism of resistance, and wider implications. Animal Canine Procedure Whole genome sequencing and phenotypic antimicrobial susceptibility testing was performed on a K. pneumoniae isolated from the urine of a dog. Results Antimicrobial susceptibility testing identified phenotypic resistance to imipenem and meropenem. Phenotypic detection of carbapenemase production was negative. Whole genome sequencing identified efflux pump genes associated with carbapenem resistance and point mutations in membrane porin genes. No carbapenemase gene was identified. Conclusion Phenotypic antimicrobial susceptibility testing identified the K. pneumoniae as a non- carbapenemase producing carbapenem-resistant organism with the proposed genotypic mechanism including alteration of efflux pumps and membrane porin activity and/or expression. Clinical significance Currently, there is limited use of carbapenem antimicrobial drugs in veterinary medicine, and practitioners may be unfamiliar or unaware of this type of resistance, its significance on routine antimicrobial susceptibility test reports, and implications for antimicrobial therapy and public health. Carbapenem-resistant Enterobacterales are infrequently isolated from companion animals; however, due to increasing adoption of advanced medical and surgical interventions, they may become more prevalent.