Colonization dynamics of Klebsiella pneumoniae in the pet animals and human owners in a single household.

Klebsiella pneumoniae resides in the gastrointestinal (GI) microbiota of humans and animals. To characterize the population dynamics of GI-colonizing K. pneumoniae, we examined the clonality of K. pneumoniae isolates, which were longitudinally collected from the fecal samplings of a healthy married couple and their pet animals during Sep. 2015 to Oct. 2016. As revealed by XbaI-PFGE analysis, the K. pneumoniae populations detected in the male owner and in one of the dogs, consisted of clonally diverse K. pneumoniae isolates; whereas, a dominant clone persisted in the GI tract of the female owner who was prone to chronic diarrhea. Whole-genome sequencing analysis of a representative strain of this pathobiont clone revealed a sequence type (ST) 29 lineage with the carriage of KL54 cps locus and a 192,603 bp IncHIB-type virulence plasmid. After probiotics intervention, the pathobiont K. pneumoniae diminished. The vacant niche was transiently occupied by other clones of K. pneumoniae, one of which was also present in the male owner. Besides the dog, the fecal carriage of K. pneumoniae was also detected in a pet turtle. This turtle isolate was resistant to multiple antimicrobials, including carbapenems. Possible transmission of drug-resistant K. pneumoniae through human-pet bonds warrants our attention.