Feed livestock with antibiotic-treated grass and produce more drug-resistant bacteria

By Maxwell Addo

Streptomycin in low concentration is used in arboriculture. When this low concentration is sprayed on grass and the grass is used for grazing sheep, there is an increase in drug-resistant bacterial populations in the feces and nasal cavity extract.  For example, percentage of Escherichia coli and Staphylococcus spp. obtained from feces and nasal cavities of sheep which graze on such fields increased as compared to those obtained before the streptomycin was applied. The E. coli was found to be resistant to sulfamethoxazole, ampicillin, tetracycline and chloramphenicol. The Staphylococcus spp. was also found to be resistant to tetracycline, fusidic acid and tiamulin.

This shows that bacteria in ruminants when exposed to antibiotics evolve into drug-resistant strains.

 

 

Figure from the article by Scherer A. et al., showing percentage of streptomycin-resistant E. coli isolated each sampling day from sheep grazing on the pasture sprayed with streptomycin (black columns) and from control sheep grazing on the untreated pasture (white) published in Environmental Mic robiology Journal, January 2013 edition.

Original Article: Scherer A, Vogt H, Vilei E. M, Frey J, Perreten V. (2012). Enhanced antibiotic multi-resistance in nasal and faecal bacteria after agricultural use of streptomycin.  Environ Microbiol 15: 297–304