Incidence of antibiotic resistance in the microbial community of the Tiber River (Rome)

The increased antibiotic use (for humans/animals, in clinics and agriculture) leads to the propagation of resistant variants in microbial communities. This phenomenon has been verified for bacterial communities in water and sediments of Tiber River. The heterotrophic aerobic isolates were checked for resistance to ampicillin, chloramphenicol, streptomycin, sulfadimethoxine and tetracycline. From 1 to 5 resistances were found in more than 80% of isolates. Sulfadimethoxine and tetracycline were ascertained to be the most and the least diffuse resistances, respectively. Resistance incidence is independent from the variation in total microbial count. Multiresistance was also observed, and 5-antibiotic-resistant isolates were mainly found in sediments. The resistance pattern has been explained in term of use and persistence of the different antimicrobials