Receptiveness of Salmonella and Arizona Strains to R Factor from Escherichia Coli in Vitro

1985

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Fifty-eight cultures of Salmonella arizonae isolated in 1983 from poultry sources and 21 cultures isolated in 1972 to 1974 were screened for resistance to nalidixic acid, chloramphenicol, triple sulfa, ampicillin, tetracycline, streptomycin, and kanamycin by the standardized disc susceptibility method. Sensitivity to all seven drugs was observed in 51% of the cultures tested (76% of the older cultures and 41% of the recent isolates). Resistance to two or more drugs was observed in 36% of the cultures tested (14% of the older cultures and 43% of the newer ones). The highest incidence of resistance was to streptomycin. Salmonella arizonae cultures sensitive to all seven drugs were tested for the ability conjugatively to acquire kanamycin, streptomycin, tetracycline, and ampicillin resistance determinants from a multiply resistant strain of Escherichia coli K12NA. Complete or intermediate resistance to all antibiotics was transferred to 93% of the sensitive cultures at 41 C and 85% at 28 C. Kanamycin resistance was transferred most frequently, and ampicillin resistance least frequently.

Section: Introductionmentioning

confidence: 96%

Incidence and In Vitro Acquisition of Transferable Drug Resistance in Salmonella arizonae

1985

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“…The rate of recovery of SAr from poults given no antibiotic in that study was much higher than that observed for the S7r recipient culture in the present study, suggesting that ST is a less effective plasmid recipient than SA. Variations in recipient competence between Salmonella strains have been previously reported (Lakhotia et al, 1972;Gast and Stephens, 1985). Differences in the abilities of various bacterial strains to act as recipients for the transfer of resistance genes can be due to a number of factors, including the presence of restriction systems that encode enzymes to degrade unmodified incoming DNA molecules (Lyon and Skurray, 1987).…”

Section: Discussionmentioning

confidence: 96%

Effects of Kanamycin Administration to Poultry on the Proliferation of Drug-Resistant Salmonella

1988

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Four experiments were conducted to examine the relationship between antibiotic administration to poultry and the in vivo proliferation of Salmonellae. The frequency of isolation of drug-resistant transconjugant S. arizonae from the livers of chicks inoculated per os with multiply drug-resistant Escherichia coli and drug-sensitive S. arizonae was directly related to the concentration of kanamycin administered to the chicks in their drinking water. Kanamycin administration was also associated with a significant (P less than .05) increase in the frequency of isolation of drug-resistant transconjugant S. typhimurium from the intestines and livers of poults inoculated with drug-sensitive S. typhimurium and multiply drug-resistant E. coli. Kanamycin administration significantly reduced the spread of drug-sensitive S. typhimurium to the livers of poults inoculated only with that strain. These experiments demonstrate that antibiotic administration to poultry can enhance the proliferation of drug-resistant Salmonella.

“…Conjugative transfer of resistance has been shown to occur in vitro at a high frequency (Lakhotia et al, 1972;Nivas et al, 1976 vivo transfer, however, has not been consistently demonstrated. Environmental factors such as temperature have been found to restrict the frequency of transfer in vivo (Smith, 1970).…”

Section: Introductionmentioning

confidence: 95%

In Vivo Transfer of Antibiotic Resistance to a Strain of Salmonella arizonae

1986

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Two trials were conducted to determine the transferability of antibiotic resistance in vivo between two strains of enteric bacteria. Newly hatched turkey poults were inoculated per os with a strain of Escherichia coli resistant to kanamycin, tetracycline, and ampicillin, a strain of Salmonella arizonae resistant to nalidixic acid and streptomycin, or both strains. Kanamycin was added to the drinking water of some poults. To test for S. arizonae cells which had received transferable resistance determinants in vivo from the E. coli strain, samples were collected by swabbing the recta of the poults and by removing segments of the intestines and livers after the birds were sacrificed. Nalidixic acid was added to the isolation media to prevent in vitro transfer from occurring after the samples were collected. Salmonella arizonae resistant to nalidixic acid, streptomycin, kanamycin, tetracycline, and ampicillin were isolated from 20% of the rectal samples taken from poults that had received both bacterial strains. S. arizonae cells which had received resistance determinants in vivo were also isolated from 73% of the intestinal samples and 8% of the liver samples taken from birds inoculated with both donor E. coli and recipient S. arizonae. Salmonella arizonae demonstrating resistance to all five antibiotics were recovered from all intestinal samples taken from birds given kanamycin in their drinking water immediately after the last S. arizonae inoculation but from only 43% of such samples taken from birds given no kanamycin.