BlaNDM gene identified from clinical samples of companion animals: First description in Brazil

Abstract

Background: Emergence of acquired carbapenemases and their worldwide dissemination are a major global threat to antibiotic era and represent a major clinical challenge in both human and veterinary contexts. Carbapenems are broad-spectrum beta-lactam antibiotics employed for treatment of serious infections, usually considered as the last-line available therapy against multidrug-resistant (MDR) Gram-negative bacterial infections like those caused by extended spectrum beta-lactamase (ESBL) pathogens. The New Delhi metallo-beta-lactamase (NDM) was named after being discovered in India, in 2009, and has been isolated in several parts of the world. Until now, the occurrence of NDM appeared to be restricted mainly to humans, however the prevalence and characteristics of MDR genes in Enterobacteriaceae originating from companion animals are still not well known. Thus, this study aimed to investigate the occurrence of carbapenemase encoding genes in bacteria resistant to carbapenems, isolated from clinical samples of companion animals. Methods and materials: There were considered bacterial isolates from dogs (97 strains) and cats (24 isolates) showing phenotypic resistance to carbapenems, identified during routine microbiological investigation between July 2018 and April 2019 in Joinville, Southern Brazil. Phenotypic resistance to carbapenems and the susceptibility profile to other common antimicrobials were determined by the disc-diffusion agar method. In addition, Modified Carbapenem Inactivation Method (mCIM) was used for phenotypic confirmation of carbapenemases in Enterobacteriaceae. The presence of blaNDM gene was confirmed by Real-time Polymerase Chain Reaction employing TaqMan probes. Results: In this study, there were identified two MDR isolates (Klebsiella pneumoniae and Enterobacter cloacae) carrying the blaNDM gene derived from dogs urine. Conclusion: To our knowledge, this is the first report of NDM identified in clinical isolates derived from companion animals in Brazil. Of note, the blaNDM gene may be located in readily transferable plasmids, increasing the variety of transmission vectors of resistance to carbapenems, also considering that the species carrying the gene identified in this study are widely distributed and shared among the environment, animals and humans.