A simplified procedure is described for screening meat and poultry tissues for the presence of antibiotic residues. The method involved inserting a cotton swab directly into meat or poultry tissues, allowing it to absorb tissue fluids. The swab is then removed and placed on a test plate using Antibiotic Medium No.5 (BBL) and a seed layer of Bacillus subtilis ATCC 6633 spores. The plate is incubated overnight at 29 C, then observed for evidence of inhibition around the swab. The method was compared with the conventional bioassay procedures using routing meat and poultry tissues submitted for analysis. Of a total 1,780 tissues tested, the screening procedure was either in agreement with or detected inhibition was not found by the conventional procedures in 99.4% of the samples. The test was shown to have equal sensitivity to conventional procedures for detection of chlortetracycline, oxytetracycline, tetracycline, erythromycin, neomycin, penicillin, streptomycin and tylosin.

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Klebsiella pneumoniae strains isolated from different clinical and environmental sources were examined for resistance to antibiotics, pentachlorophenol, and heavy metals using intracellular ATP measurements. Resistance to kanamycin, neomycin, gentamicin, and tobramycin was noted for the hospital strain but not for the environmentally derived isolates. On the other hand, strains isolated from pulp and paper mill effluents and receiving waters exhibited a higher degree of pentachlorophenol and heavy metal resistance. Chromosomal restriction endonuclease analysis (REA) digests of three environmental strains produced patterns that were different and readily distinguishable. Plasmids were detectable in these same environmental isolates; two of the three carried a 70 × 106 Da plasmid that is thought to mediate both antibiotic and heavy metal resistance.