Antibiotic resistance and phylogenetic profiling of Escherichia coli from dairy farm soils; organic versus conventional systems.

The prevalence and spread of antimicrobial resistance (AMR) as a result of the persistent use and/or abuse of antimicrobials is a key health problem for health authorities and governments worldwide. A study of contrasting farming systems such as organic versus conventional dairy farming may help to authenticate some factors that may contribute to the prevalence and spread of AMR in their soils. A case study was conducted in organic and conventional dairy farms in the South Canterbury region of New Zealand. A total of 814 dairy farm soil E. coli (DfSEC) isolates recovered over two years were studied. Isolates were recovered from each of two farms practicing organic, and another two practicing conventional husbandries. The E. coli isolates were examined for their antimicrobial resistance (AMR) against cefoxitin, cefpodoxime, chloramphenicol, ciprofloxacin, gentamicin, meropenem, nalidixic acid, and tetracycline. Phylogenetic relationships were assessed using an established multiplex PCR method. The AMR results indicated 3.7% of the DfSEC isolates were resistant to at least one of the eight selected antimicrobials. Of the resistant isolates, DfSEC from the organic dairy farms showed a lower prevalence of resistance to the antimicrobials tested, compared to their counterparts from the conventional farms. Phylogenetic analysis placed the majority (73.7%) of isolates recovered in group B1, itself dominated by isolates of bovine origin. The tendency for higher rates of resistance among strains from conventional farming may be important for future decision-making around farming practices Current husbandry practices may contribute to the prevalence and spread of AMR in the industry.

Proteomics and the stressful life of lactobacilli.

Lactobacilli occupy specific ecological niches, where they represent a major component of foods, human and animal microbial communities. Employing these bacteria in industrial fermentations or for human health benefits exposes them to certain life-threatening conditions where their ability to adapt plays a key role in their survival and continued microbial activity. Since the postgenomic era began, proteomics has become the first choice among research approaches available for environmental adaptation and stress response investigators. The latest developments in the applications of proteomics to understand physiological changes in Lactobacillus species under harsh conditions are remarkable.