CDC, several states, and the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS) are investigating a multistate outbreak of multidrug-resistant Campylobacter infections.
Campylobacter bacteria isolated from clinical samples from people sickened in this outbreak are resistant to commonly recommended, first-line antibiotics. This means it may be difficult to treat these infections with the antibiotics usually prescribed for Campylobacter infections.
As of December 12, 2017, 97 people with laboratory-confirmed infections or symptoms consistent with Campylobacter infection have been linked to this outbreak. Illnesses have been reported from 17 states. Twenty-two (24%) of 91 ill people with available information have been hospitalized. No deaths have been reported.
Epidemiologic and laboratory evidence indicates that contact with puppies sold through Petland stores is a likely source of this outbreak.
Of 89 people interviewed, 87 (98%) reported contact with a puppy in the week before illness started. Of 88 people interviewed, 79 (90%) reported they had contact with a puppy from a Petland store, or had contact with a person who became sick after contact with a puppy from a Petland store. Twenty-one ill people worked at a Petland store.
Whole genome sequencing (WGS) showed that the Campylobacter isolates from sick people in this outbreak and isolates from pet store puppies were closely related genetically, providing additional evidence that people got sick from contact with pet store puppies.
Antibiotic resistance may be associated with increased risk of hospitalization, development of a bloodstream infection, or treatment failure in patients.
Using WGS, we identified multiple antimicrobial resistance genes and mutations in most isolates from 35 ill people and 9 puppies in this outbreak. This finding matches results from standard antibiotic susceptibility testing methods used by CDC’s National Antimicrobial Resistance Monitoring System laboratory on isolates from five ill people and seven puppies in this outbreak.
The 12 isolates tested by standard methods were resistant to azithromycin, ciprofloxacin, clindamycin, erythromycin, nalidixic acid, telithromycin, and tetracycline. In addition, 10 were resistant to gentamicin, and 2 were resistant to florfenicol.
This investigation is ongoing and we will provide updates as more information becomes available.