A study conducted in Germany suggests the interaction between people and their pets is not a major factor in the spread of multidrug-resistant organisms (MDROs), researchers reported last week in Antimicrobial Resistance & Infection Control.
For the study, researchers at Charite University Hospital in Berlin performed whole-genome sequencing (WGS) and core genome multilocus sequence typing (cgMLST) on 252 human, 53 dog, and 10 cat isolates collected from a larger case-control study that examined MDRO risk factors among MDRO-positive and MDRO-negative patients. The analysis focused on pet owners and their pets. While several studies in recent years have reported the identification of genetically similar MDROs in people and pets living in the same household using WGS, the study authors say cgMLST, which offers greater discriminatory power and more precise strain typing, has rarely been used.
A total of 154 human isolates (24.6% of the 626 pet owners in the larger study) and 62 pet isolates (11.9% of the 514 pets in the larger study) tested positive for MDROs. Of the bacterial species detected in the isolates, five MDROs that were present in people and at least one pet species (methicillin-resistant Staphylococcus aureus [MRSA], vancomycin-resistant Enterococcus [VRE], and multidrug-resistant [MDR] Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae) were selected for comparison to identify potential transmission.
Most of the analyzed isolates showed high genetic diversity, with only minor overlaps between people and pets. Only two human-pet pairs were colonized with MDROs (VRE and MDR E coli), which showed no genetic difference, a finding the study authors say could indicate transmission or acquisition from a common source. In addition, significantly more pet owners than pets were MDRO-positive.
"This suggests that the interaction between humans and their pets appears to play a minor role in the spread of the MDROs," the authors wrote. "Pets might act as spillover hosts rather than reservoirs for MDROs with transmission potential to humans. Yet, the possibility of transmission from a shared source remains."
They add that future studies should include other possible transmission routes and common sources of resistant strains.