Chemical decontaminants could favour the emergence, selection and/or proliferation of antibiotic-resistant strains in microbial populations on poultry meat, according to Rosa Capita and colleagues at the Department of Food Hygiene and Food Technology at the University of León in Spain.

In a paper published online ahead of print in Food Microbiology, they report a study to determine the ability of various decontaminants to increase the prevalence of resistance to antibiotics in Escherichia coli populations on poultry.

Chicken legs were dipped for 15 minutes into aqueous solutions (wt/vol) of trisodium phosphate (TSP; 12 per cent), acidified sodium chlorite (ASC; 1200 ppm), ascorbic acid (AA; 2.0 per cent) or citric acid (CA; 2.0 per cent) or tap water (control).

Samples were analysed immediately after treatment (day 0) and after five days of storage at 7±1°C. A total of 250 E.coli isolates (50 from each group of samples; 25 on day 0 and 25 on day 5) were tested against 12 antibiotics of clinical significance by means of a standard disc-diffusion technique.

The researchers observed a high prevalence of resistance to antibiotics for E.coli strains from control samples, with three (6.0 per cent) isolates sensitive, three (6.0 per cent) resistant to one antibiotic and 44 (88.0 per cent) isolates resistant to two or more antibiotics.

Isolates from control samples had a lower prevalence of resistance than those from treated samples to ampicillin-sulbactam (P<0.01, samples treated with TSP), amoxicillin-clavulanic acid (P<0.001, ASC, AA and CA), cephotaxime (P<0.05, TSP), trimethoprim-sulphamethoxazole (P<0.05, AA; P<0.01, CA), tetracycline (P<0.01, CA), ciprofloxacin (P<0.001, ASC; P<0.05, AA; P<0.01, CA) and nitrofurantoin (P<0.01, TSP).

Trisodium phosphate, acidified sodium chlorite and two organic acids were all effective in reducing the microbial load on poultry during storage. However, the treatments increased the level of resistance to antibiotics in E.coli populations. Treated samples showed the highest prevalence of resistance for 58.33 per cent of antibiotics.

Capita and colleagues concluded their results suggest that the chemical decontaminants tested could favour the emergence, selection and/or proliferation of antibiotic-resistant strains in microbial populations on poultry meat.

Reference

Capita R., E. Álvarez-Fernández, E. Fernández-Buelta, J. Manteca and C. Alonso-Calleja. 2012. Decontamination treatments can increase the prevalence of resistance to antibiotics of Escherichia coli naturally present on poultry. Food Microbiology, 34 (1), May 2013: p112–117. [Online ahead of publication]. dx.doi.org/10.1016/j.fm.2012.11.011.

Further Reading You can view the full report by clicking here.