ANTIMICROBIAL SUSCEPTIBILITY OF SALMONELLA ISOLATES OBTAINED FROM WEST TEXAS SHEEP: A STUDY INTO BACTERIAL RESISTANCE

Antibiotic resistance is becoming an increasingly prevalent issue within the health and food production industries. The purpose of this study is to analyze antimicrobial susceptibility in Salmonella isolates from small ruminants due to the lack of available literature. Salmonella is one bacterial pathogen often found in sheep. Using Sensititre® susceptibility plates, 24 confirmed isolates of Salmonella spp. were tested against 15 of the most important antibiotics determined by the National Antimicrobial Resistance Monitoring System. The data obtained was compared against the NARMS determined breakpoints and analyzed using various processes of Statistical Analysis Software (SAS). Of the 24 isolates tested, 58.33% exhibited resistance to antibiotics, specifically 37.5% were found to be resistant to only one of the antimicrobials tested against, 4.17% were resistant to two antimicrobial drugs, 12.5% of the isolates were resistant to three antimicrobials and 4.17% were resistant to a total of five antimicrobials. The most commonly observed resistance was to Tetracycline at 50%. There were eight antimicrobials that the Salmonella isolates showed no significant resistance to, and seven antimicrobials where the minimum inhibitory concentration was found to be higher than the reported breakpoint. Results from this study show that some antibiotic resistance does exist within Salmonella obtained from sheep related sources, and prudent use of antibiotics should be advocated to help prevent further spread of resistance.