CRISPRs are present in many foodborne pathogens. The researchers demonstrated that CRISPR sequences can be used to identify populations of Salmonella with common antibiotic-resistance patterns in both animals and humans.
"Specifically, we were able to use CRISPRs to separate isolates by their propensity for resistance to seven common veterinary and human clinical antibiotics," DiMarzio said. "Our research demonstrates that CRISPRs are a novel tool for tracing the transmission of antibiotic-resistant Salmonella Typhimurium from farm to fork."
DiMarzio found that several subtypes of Salmonella Typhimurium showed up repeatedly in the frozen collection of Salmonella samples taken from cows, pigs and chickens in Penn State's Animal Diagnostic Laboratory. In this case, researchers looked at 84 unique Salmonella Typhimurium isolates collected from 2008 to 2011.
"We know those strains are widely disbursed, and the thing they have in common is that they have noticeably higher levels of antibiotic resistance," he said. "So we examined clinical samples of Salmonella taken from humans, and it turned out that we see an overlap -- the ones we see in humans are the ones we see a lot in animals. You would expect that, but it is confirmation that our method works."
DiMarzio noted that the researchers identified subsets of the overall Salmonella bacteria population that seem to be more prone to acquiring antibiotic resistance.
"Our challenge now is to learn what makes those strains different -- why do some strains acquire resistance while others don't, even though both are circulating wid
|Contact: A'ndrea Elyse Messer|