Antibiotic Resistance in Yogurt Bacteria

Probiotics are live microorganisms that benefit gut health in their host. Antibiotic resistance refers to the ability of bacteria becoming tolerant to antibiotic treatments. As the antibiotics are now useless, this resistance can cause difficulties in the treatment of bacterial infections. This study investigated the difference in antibiotic resistance in bacteria found in a probiotic yogurt vs. greek yogurt by testing the effectiveness of five antibiotics: penicillin, ampicillin, tetracycline, streptomycin, and chloramphenicol. We are investigating the research question: Is there a significant difference in antibiotic resistance in bacteria from probiotic plain whole milk yogurt vs. non-probiotic greek yogurt? Using sterile techniques, we grew bacteria from yogurt solutions and exposed them to antibiotic-containing disks. We then measured zones of inhibition around each antibiotic disk as a measure of antibiotic resistance. Preliminary results show that there was more antibiotic resistance found in the bacteria from the greek yogurt samples when compared to the probiotic yogurt samples. Antibiotic resistance in these products could have public health implications if these bacteria transfer resistance genes to pathogens. Future experiments will investigate the specific bacteria present in probiotic yogurt, the genetic basis of their resistance, and the implications for human health.