Feeding livestock with streptomycin-treated grass leads to an increase in drug-resistant bacterial populations in the body of ruminants

By Maxwell Addo

Streptomycin in low concentration is used in arboriculture. When this low concentration is sprayed on grass and the grass is use to graze 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.

 

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 Microbiology 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. Environmental Microbiology  15: 297–304