Occurrence and patterns of antibiotic resistance in vertebrates 1 off the Northeastern United States coast 2 3 4 5

2 3 The prevalence of antibiotic-resistant bacteria in the marine environment is a growing 4 concern, but the degree to which marine mammals, seabirds and fish harbor these organisms is 5 not well documented. This project sought to identify the occurrence and patterns of antibiotic 6 resistance in bacteria isolated from vertebrates of coastal waters in the northeastern United 7 States. 472 isolates of clinical interest were tested for resistance to a suite of 16 antibiotics. 8 Fifty-eight percent were resistant to at least one antibiotic, while 43% were resistant to multiple 9 antibiotics. A multiple antibiotic resistance (MAR) index value greater than or equal to 0.2 was 10 observed in 38% of the resistant pathogens, suggesting exposure of the animals to bacteria from 11 significantly contaminated sites. Groups of antibiotics were identified for which bacterial 12 resistance commonly co-occurred. Antibiotic resistance was more widespread in bacteria 13 isolated from seabirds than marine mammals, and was more widespread in stranded or bycaught 14 marine mammals than live marine mammals. Structuring of resistance patterns based on sample 15 type (live/stranded/bycaught) but not animal group (mammal/bird/fish) was observed. These 16 data indicate that antibiotic resistance is widespread in marine vertebrates, and they may be 17 important reservoirs of antibiotic resistant bacteria in the marine environment. 18 19