It has been shown that the use of antibiotics promotes resistance to that antibiotic, and that colonization with resistant pathogens can be transmitted from companion animals to their human owners. There is an evolving concern that use of medically important antibiotics in pets can confer colonization by resistant organisms in their human owners.
In dogs receiving amoxicillin/clavulanate for 14 days for a diagnosed infection, we screened stool both at the time of antibiotic initiation and at the end of the course for the dog taking antibiotics and their human owner. Owners had to meet a closeness score of 3 or 4, meaning living in same household with frequent contact, with or without oral contact, and have no recent antibiotic exposure. Stool samples were quantitatively cultured for enteric flora and incubated on selective media for ampicillin/sulbactam resistance (A/S-r), ciprofloxacin resistance (CIP-r), ESBL, MRSA, and VRE.
We enrolled 8 dog-human pairs. All had enteric flora present at the time of antibiotic initiation (day 1), whereas 2 of the 7 dog samples that could be analyzed had no detectable enteric flora by the end of antibiotics (day 14). No humans or dogs acquired MRSA or VRE. One human lost colonization with CIP-r flora, whereas two dogs acquired CIP-r during antibiotic treatment that did not transmit to their owners. One dog and one unrelated human acquired ESBL colonization by day 14 that was not present at day 1. There were 3 humans colonized with A/S-r on day 1 which persisted through the treatment period. Of their 3 dogs, one had no A/S-r at either time point, one newly acquired high counts of A/S-r flora, and one did not provide enough stool at day 14 for A/S-r testing. There was one other dog that acquired A/S-r flora and one dog that had increasing counts of A/S-r, both of which had human owners with no A/S-r on day 1 or 14.
In this pilot study, we identified that use of amoxicillin-clavulanate, a common antibiotic prescribed to both humans and dogs, can lead to resistant colonization in the dog taking antibiotics, and may have some impact on their close human owners who may share or transmit colonization. Further study is under way to better understand this relationship.
K. R. Beaulac,
C. Fellman, None
A. Wayne, None
L. A. McDermott, CutisPharma Inc.: Research Contractor , Contractual agreement with Tufts Medical Center .
D. Snydman, None