Antibiotic-resistant coliforms in the waste of piggeries and dairy farms.

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Abstract
To examine incidence of coliforms and drug-resistant Escherichia coli, a total of 22 swine and 19 bovine waste samples were collected from 8 piggeries and 9 dairy farms in Japan in 1976 and 1977. Chemical oxygen demand (COD), suspended solid (SS), pH values and the number of coliforms with or without antibiotic resistance were measured to analyze for the correlation function. Except for the correlation between the coliform count and the pH value of bovine urine storage samples, no significant correlation was observed. Coliforms in bovine urine storage samples of alkalinity were fewer than other samples. Waste treatment on a piggery (farm E) was effective in decreasing COD and coliforms in the waste. A total of 449 (97%) of 465 E. coli strains isolated from swine samples and 180 (78%) of 230 strains from bovine samples were resistant to at least one of the following: ampicillin, furatrizine, chloramphenicol, kanamycin, streptomycin(Sm), sulfonamide(Su) and tetracycline(Tc). Resistance to Tc, Sm and Su was common in E. coli strains from swine and bovine samples but incidence of resistant strains from swine samples was generally higher than that from bovine samples. The drug resistance patterns (47 patterns) of swine E. coli strains were more complicated than those (24 patterns) of bovine strains. Conjugative R plasmids were detected in swine (56%) and bovine samples (33%). Thirteen (22%) thermosensitive R plasmids were found only in swine samples. Animal waste heavily contaminated with drug resistant coliforms can be a potential source of environmental pollution.