A newly published report by researchers at Penn State University’s College of Agricultural Sciences in the USA describes a new approach to studying the development and spread of antibiotic resistance in Salmonella Typhimurium strains.
Lead researchers Michael DiMarzio and his colleagues used a subtyping method based on regions of the bacterial genome called clustered regularly interspaced short palindromic repeats (CRISPRs), which are found in many foodborne pathogens. The method, CRISPR-multi-virulence-locus sequence typing (CRISPR-MVLST), is able to differentiate between strains of several common Salmonella serovars and was used to identify 22 sequence types within a collection of 76 S. Typhimurium isolates from animals.
Further experiments showed that the technique could also identify populations with common antibiotic resistance patterns in animals and humans and could differentiate isolates by their propensity for resistance to seven commonly used antibiotics.
The report’s authors suggest that the technique could be useful for tracing the spread of antibiotic resistance in S. Typhimurium throughout the food supply chain. This has been very difficult to achieve up to now because resistance patterns in bacteria evolve so rapidly.
The report is published in the journal Antimicrobial Agents and Chemotherapy and an abstract can be found here.