Heavy metals have been implicated for their ability to increase antibiotic resistance in bacteria collected from polluted waters, independent of antibiotic exposure, reports M. Nisanian of the University of Georgia and co-authors in a paper in Poultry Science.

In their experiment, specific-pathogen-free Leghorn chickens were given lead acetate in the drinking water to expose the enteric bacteria to lead and to determine if antibiotic resistance changed in these bacteria.

Concentrations of lead used were 0.0, 0.01, 0.1, 1.0 or 10.0mM; birds given the highest two concentrations showed signs of moribundity and dehydration and were removed from the study.

Vent culture samples were collected for bacterial cultures on day 0 before lead exposure, days 7 and 14 and then birds were euthanised by carbon dioxide for necropsy on day 14, at which time intestinal contents were also collected for bacterial cultures.

Faecal swabs but not intestinal samples from lead-exposed birds contained isolates that had significantly elevated antibiotic resistance. Some of the isolates contained bacteria that were resistant to up to 20 antibiotics.

Nisanian and co-authors conclude their results suggest the need for repeated studies in chickens infected with zoonotic pathogens.

Reference

Nisanian M., S.D. Holladay, E. Karpuzoglu, R.P. Kerr, S.M. Williams, L. Stabler, J. Vaun McArthur, R.C. Tuckfield and R.M. Gogal Jr.2014. Exposure of juvenile Leghorn chickens to lead acetate enhances antibiotic resistance in enteric bacterial flora. Poultry Science. 93(4):891-897. doi: 10.3382/ps.2013-03600

Further Reading

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