The Effects on Human Health of Subtherapeutic Use of Antimicrobials in Animal Feeds (1980) / Chapter Skim
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Appendix E: Antimicrobial Residues and Resistant Organisms: Their Occurrence, Significance, and Stability
Appendix E: Antimicrobial Residues and Resistant Organisms: Their Occurrence, Significance, and Stability
Pages 158-181
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From page 158... ...
Because of the extreme variability in both the use of drugs and adherence to withdrawal periods, it is inevitable that residues would occur in a small but significant percent of animal products found in the marketplace. RESIDUE LEVELS FROM SUBTHERAPEUTIC ANTIBIOTIC USE Huber (1971)
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From page 159... ...
After a 5-day withdrawal period, there were no measurable levels in muscle, and only trace levels could be found in the liver. OTC residues occurring in poultry muscle from the continuous feeding of 25 to 200 g/ton were approximately 1/1,000 of the feeding level.
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From page 160... ...
160 TABLE l Violative Actions for Antibiotics and Sulfonamides Ant ibiot icViola- SulfonamideViola Species SamplesLions ~SamplesLions 1976: Cattle 54571.347640.9 Calves 1, 37 81 188.
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From page 161... ...
Approximately 98% of the penicillin activity was destroyed in the upper portion of the intestinal tract, and little or no activity reached the small intestine (Katz et al., 1974; Messersmith et al., 1967~. One of the major degradation products was penicilloic acid.
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From page 162... ...
FATE OF ANTIBIOTIC RESIDUES Residues of the tetracyclines in the muscle tissue of animals will not survive normal food preparation procedures. No residues will enter the diet of humans unless the muscle tissue is eaten raw or very rare.
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From page 163... ...
Such inactivation would undoubtedly lead to the formation of penicilloic acid and the possible adsorption and deposition of this compound into muscle tissue. The use of injectables and the residues resulting from them can always be a source of unwanted and potentially dangerous residues.
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From page 164... ...
However, it is known that the breakdown products of penicillin do have biological significance ranging from their ability to sensitize individuals to their action as selecting agents for the development of antibiotic resistance in _ colt. Since up to 10% of the population is potentially sensitive to penicillin and its breakdown products, the risk is too great to be ignored.
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From page 165... ...
Residue levels are usually low, contact tome in relation to the number of generations relatively short, the nutritional requirements too variable and usually insufficient for sustained growth, and the temperature of storage too low for growth. The selection process requires the inhibition of susceptible strains, thereby allowing the more resistant strains to grow.
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From page 166... ...
Only through monitoring and changes in agricultural practice can the problem be minimized. State Agricultural Experiment Stations, through their research and extension arms, should provide the farmer with the knowledge to develop proper agricultural practices.
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From page 167... ...
Van Dijck and Van de Voorde (1976) reported that 12 of 41 water samples showed inhibitory activity against Staphylococcus aureus, but believed that the low activity in the water samples posed no hazard.
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From page 168... ...
Although soluble, weakly absorbed, and potentially mobile in the soil, it is doubtful that the tetracyclines will be a strong selective agent. SHEDDING OF RES ISTANT ORGANISMS Animals fed antibiotics shed antibiotic-resistant organisms (Smith, 1969; Smith and Crabb, 1957~.
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From page 169... ...
Ketch and Lee (1978) noted that the antibiotic resistance pattern of Gram-negative bacteria of different genera correlated well with patterns found with E
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From page 170... ...
He reported that 48.7Z of the total coliform isolates from tainted wells were resistant to one or more antibiotics, 67.5% of the isolates from the freshwater mussel had multiple antibiotic resistance, and 71.5Z of the coliforms isolated from seawater were resistant. Because of these relatively high percentages of resistance, Cooke hypothesized that antibiotic-resistant bacteria may have a selective advantage for survival once these organisms are disseminated into natural waters.
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From page 171... ...
He suggested that the rapid decline in the resistant organisms resulted from an impaired vitality of the organisms rather than the loss of R factors from the cell. Although there is a difference of opinion regarding whether resistant strains have a selective advantage for survival in the environment over nonresistant strains, the evidence in favor of their not having a selective advantage is more compelling.
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From page 172... ...
The incidence of antibiotic residues in animal products will continue at a relatively modest rate regardless of surveys and enforcement procedures. The current surveillance procedures are extremely effective in identifying problem areas, but no regulatory system can guarantee a residue-free food supply.
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From page 173... ...
(7) Although animal agriculture contributes drug-resistant species to the environment, especially in rural areas, human beings rather than animals appear to be the main source of antibiotic-resistant organisms in the environment.
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From page 174... ...
1976a. Antibiotic resistance among coliform and faecal colifonm bacteria from natural waters and effluents.
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From page 175... ...
197 fib. Antibiotic resistance among coliform and fecal coliform bacteria isolated from the freshwater mussel Hydridella menziesii.
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From page 176... ...
1967. Disappearance of chlortetracycline residues from edible tissues of animals fed rations containing the drug.
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From page 177... ...
1978. Antibiotic resistance patterns of gram-negative bacteria isolated from environmental sources.
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From page 178... ...
1967. Safety and tissue residue evaluations in swine fed rations containing chlortetracycline, sulfamethazine, and penicillin.
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From page 179... ...
1969. The influence of antimicrobial drugs in animal feeds on the emergence of drug-resistant, diseaseproducing bacteria in animals.
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From page 180... ...
1974. Objective Phase Biological Residue Reports, January through December 1973.
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From page 181... ...
1978. Diagnosis of penicillin allergy by skin testing: The Manitoba experience.
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