Abstract
Antibiotics are fundamental to modern medicine. Unfortunately, antimicrobial resistance threatens the continued effectiveness of these tools for human and veterinary medicine.1 The aquatic environment is a particularly important source of emerging antimicrobial resistance, due to both natural and human-origin drivers.2 Because of their natural history, gray seals (Halichoerus grypus) are an ideal sentinel species and have previously contributed to surveillance studies of antimicrobial resistance in the nearshore marine environment of the northwest Atlantic.3,4 To continue surveillance for antimicrobial resistant pathogens of concern for both wildlife and human public health from the nearshore ecosystem, this study cultured nasal and rectal swabs collected from gray seal pups shortly after weaning along Cape Cod, Massachusetts. By sampling very young and apparently healthy individuals, instead of sick, injured, or stranded individuals, this study aimed to identify pathogens of interest with antimicrobial resistance that may colonize individuals regardless of health status and immunocompetency. One hundred forty-nine isolates were grown from 48 rectal swabs and 101 isolates were grown from 47 nasal swabs. For each isolate tested for antimicrobial resistance a Multiple Antimicrobial Resistance (MAR) index was calculated. 57 rectal isolates (56 Enterococcus sp. and one Proteus sp. isolate), and only 1 nasal isolate (Staphylococcus pseudintermedius) had a MAR above 0.2, the level considered significant.5 The results of this study were consistent with previous broad surveillance conducted in the Massachusetts marine nearshore ecosystem.4 These results highlight the significance of Enterococci species as pathogens of potential concern for significant antimicrobial resistant infections, and continue to demonstrate the potential risk of environmentally acquired infections for both wildlife and humans.6–8
Acknowledgments
The authors thank the Gorey Foundation, the Tufts Institute for the Environment, and NIH NIAID for funding (grant HHSN272201400008C) as well as the National Marine Fisheries Service Northeast Science Center, Monomoy National Wildlife Refuge, and all members of the field team who assisted with sample collection.
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