The Incidence of Antibiotic Resistance in Mesophilic Aeromonas Isolated from the Buffalo River and from a Non-Urban Site Upstream

Antibiotics are commonly used in agriculture and industry and their discharge is commonly seen in rivers, like the Buffalo River. This antibiotic discharge may cause a selective environment which favors the growth of antibiotic resistant Aeromonas. To study the effect of urban pollution on the antibiotic resistance in Aeromonas, 229 Aeromonas isolates were collected from fish tissues as well as sediment and water samples collected from the Buffalo River and a non-urban site (Cazenovia Creek). Seven different Aeromonas taxa were identified using biochemical tests. There were 124 (54%) isolates that were classified as atypical, which was the most commonly seen taxon. Aeromonas veronii biovar sobria was the most common species identified (63 isolates, 28%). All Aeromonas isolates were tested for their resistance to six different antibiotics (cephalothin, cefoxitin, ceftriaxone, nalidixic acid, piperacillin, and tetracycline). A total of 104 of 105 (\u3e 99%) antibiotic-resistant isolates were resistant to cephalothin. All of the tested Aeromonas isolates had a cephalothin MIC greater than 32µg/ml. The cephalothin resistant isolates from the non-urban site all had an MIC greater than 256µg/ml. This study can be used to guide future studies in antibiotic resistance from the Buffalo River watershed