Evidence of Sharing of Klebsiella pneumoniae Strains between Healthy Companion Animals and Cohabiting Humans

Abstract

This study aimed to characterize the fecal colonization and sharing of <i>Klebsiella pneumoniae</i> strains between companion animals and humans living in close contact. Fecal samples were collected from 50 healthy participants (24 humans, 18 dogs, and 8 cats) belonging to 18 households. Samples were plated onto MacConkey agar (MCK) plates with and without cefotaxime or meropenem supplementation. Up to five <i>K. pneumoniae</i> colonies per participant were compared by pulsed-field gel electrophoresis (PFGE) after XbaI restriction. <i>K. pneumoniae</i> strains with unique pulse types from each participant were characterized for antimicrobial susceptibility, virulence genes, and multilocus sequence type (MLST). Fecal <i>K. pneumoniae</i> pulse types were compared to those of clinical <i>K. pneumoniae</i> strains from animal and human patients with urinary tract infections (<i>n</i> = 104). <i>K. pneumoniae</i> colonization was detected in nonsupplemented MCK in around 38% of dogs (<i>n</i> = 7) and humans (<i>n</i> = 9). <i>K. pneumoniae</i> strains isolated from dogs belonged to sequence type 17 (ST17), ST188, ST252, ST281, ST423, ST1093, ST1241, ST3398, and ST3399. None of the <i>K. pneumoniae</i> strains were multidrug resistant or hypervirulent. Two households included multiple colonized participants. Notably, two colonized dogs within household 15 (H15) shared a strain each (ST252 and ST1241) with one coliving human. One dog from H16 shared one PFGE-undistinguishable <i>K. pneumoniae</i> ST17 strain with two humans from different households; however, the antimicrobial susceptibility phenotypes of these three strains differed. Two main virulence genotypes were detected, namely <i>fimH-1 mrkD ycfM entB kfu</i> and <i>fimH-1 mrkD ycfM entB kpn</i> These results highlight the potential role of dogs as a reservoir of <i>K. pneumoniae</i> to humans and vice versa. Furthermore, to our best knowledge, this is the first report of healthy humans and dogs sharing <i>K. pneumoniae</i> strains that were undistinguishable by PFGE/MLST.