Emergence of a New Delhi Metallo--Lactamase (NDM-1)-Encoding Gene in Clinical Escherichia coli Isolates Recovered from Companion Animals in the United States

The rapid spread of extended-spectrum -lactamases (ESBLs)and quinolone resistance in Escherichia coli in companion an-imals (1, 2) has increased concern among veterinarians to find an alternative therapy to treat clinical infections caused by these re-sistant organisms. Up until now, the prevalence of carbapen-emases appeared to be restricted mainly to humans (3–5). More recently, studies have reported the presence of E. coli producing VIM-1 carbapenemase, isolated on a pig farm inGermany (6), and Acinetobacter baumannii expressing OXA-23, isolated from cattle in France (7). In the United States, carbapenems are not licensed for treatment of companion animals, and we are unaware of car-bapenemase producers from companion animals. In this study, we describe the first report of detection of a New Delhi metallo--lactamase (NDM)-encoding gene (NDM-1) in multidrug-re-sistant strains of E. coli recovered from companion animals in the United States