Introduction: We studied the richness and abundance of ant species, their bacteria and the bacteria isolated from patient clinical samples.
Methods: Ants were collected with baited traps at 64 sites in a public hospital in São Luis, State of Maranhão, Brazil.
Results: In total, 1,659 ants from 14 species were captured. The most frequent species were Crematogaster victima, Solenopsis saevissima, Tapinoma melanocephalum, Camponotus vittatus and Paratrechina fulva. Forty-one species of bacteria were isolated from the ants and 18 from patients.
Conclusions: Ants are potential vehicles for pathogenic and opportunistic bacteria, and they can represent a risk factor in nosocomial infections.