Fluctuations in <i>Escherichia coli</i> O‐serotypes in Pigs Throughout Life in the Presence and Absence of Antibiotic Treatment

Linton, A. H.; Handley, B.A.; Osborne, A. D.

doi:10.1111/j.1365-2672.1978.tb00801.x

Cited by 18 publications

(12 citation statements)

References 13 publications

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“…The relationship of age and antibiotic resistance of E. coli from the intestinal tract is difficult to explain, as young pigs have been exposed to the microflora of their dams. Other investigators, however, (Soogard 1973; Linton et al 1978;Hinton et al 1985;Hinton 1986) have reported higher levels of resistance and greater incidence of multiple resistance in young animals and in children than in older animals and adults. The relationship of age and antibiotic resistance may suggest that the gastrointestinal tract in younger animals may be colonized more readily than in older animals by antibiotic-resistant organisms in the absence of any antibiotic selection pressure (Hartley and Richmond 1975;Petrocheilou et al 1976Petrocheilou et al , 1977.…”

Section: Resultsmentioning

confidence: 96%

Effects of cold stress on the antimicrobial drug resistance of Escherichia coli of the intestinal flora of swine

Moro¹,

Beran²,

Hoffman³

et al. 1998

Lett Appl Microbiol

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Faecal samples were initially collected from pigs of different age groups, over periods considered to be seasonally normal and stable (baseline), and during times in which drastic drops in environmental temperature (cold stress) occurred. Baseline bacterial resistance to ampicillin and tetracycline were significantly higher (P < 0.05) in younger than in older pigs. Also, when animals were exposed to excessively cold conditions, there was a significant (P < 0.05) increase in ampicillin and tetracycline resistance in Escherichia coli for animals of all age groups. These results may indicate that factors other than feeding or use of antibiotics may play a role in establishing or maintaining the antibiotic resistance microflora of pigs, especially in those operations where animals are maintained outdoors, with minimal protection against extreme weather conditions.

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Section: Resultsmentioning

confidence: 96%

Effects of cold stress on the antimicrobial drug resistance of Escherichia coli of the intestinal flora of swine

Moro¹,

Beran²,

Hoffman³

et al. 1998

Lett Appl Microbiol

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

Effects of cold stress on the antimicrobial drug resistance ofEscherichia coliof the intestinal flora of swine

Moro

Beran

Hoffman

et al. 1998

Letters in Applied Microbiology

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M .H . M O RO , G . W. BE R AN , L . J. HO F FM AN A ND R. W . G RI F FI TH . 1998. Faecal samples were initially collected from pigs of different age groups, over periods considered to be seasonally normal and stable (baseline), and during times in which drastic drops in environmental temperature (cold stress) occurred. Baseline bacterial resistance to ampicillin and tetracycline were significantly higher (P ³ 0·05) in younger than in older pigs. Also, when animals were exposed to excessively cold conditions, there was a significant (P ³ 0·05) increase in ampicillin and tetracycline resistance in Escherichia coli for animals of all age groups. These results may indicate that factors other than feeding or use of antibiotics may play a role in establishing or maintaining the antibiotic resistance microflora of pigs, especially in those operations where animals are maintained outdoors, with minimal protection against extreme weather conditions.

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“…The more complex the E. coli flora the greater the number of colonies that has to be examined in order to obtain a reasonable estimate of the majority of O serogroups present in the sample. However, small samples have a value, as indicated in one study which showed that at least 76% of the majority of serotypes could be detected when 10 colonies were selected ( Linton et al . 1978 ).…”

Section: Resultsmentioning

confidence: 99%

Effects of heat stress on the antimicrobial drug resistance of Escherichia coli of the intestinal flora of swine

et al. 2000

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The effects of heat stress on the antimicrobial drug resistance of Escherichia coli of the intestinal tract of swine were studied in animals from a farm that had not been supplementing antimicrobials in feed for the past 10 years. In one study, 10 ®nisher hogs were heat stressed (34 C) for 24 h. Antimicrobial resistance levels after stress were signi®cantly higher (P < 0Á05) when compared with pre-stress levels for amikacin, ampicillin, cephalothin, neomycin and tetracycline from faecal samples. This high level of resistance persisted to slaughter that occurred at 10 days post-stress for most of the antimicrobials mentioned. In a second study, samples of different sections of the gastrointestinal tract were collected after heat stress and compared with control, non-stressed animals. Results indicated that E. coli which colonized the ileum and caecum had a higher level of resistance to ampicillin and tetracycline than the E. coli which colonized the colon and rectum. When animals were exposed to heat stress, resistance to ampicillin and tetracycline of E. coli in the lower digestive tract increased (P < 0Á05) to a level similar to that observed in the ileum and caecum. Based on these ®ndings, an investigation was made to test the hypothesis that (a) an increase in intestinal motility increases shedding of resistant E. coli and (b) heat stress induces a reduction in intestinal transit time in swine. For each study, two groups of three, randomly selected ®nisher hogs each were formed (treated and control groups). In study (a), induction of increased motility and peristalsis was obtained using an intramuscular injection of the cholinergic drug neostigmine methylsulphate. Escherichia coli isolates were obtained from the ileum, caecum, colon and rectum after animals were slaughtered. A higher level of ampicillin-resistant E. coli was found in the caecum (40%) than in other segments of the intestinal tract. In treated animals, level of resistance increased for organisms from the colon and rectum. Similar results were obtained for tetracycline resistance. In study (b), intestinal transit time was measured using chromium-EDTA as a marker. Swine were euthanized and samples were collected throughout the intestinal tract (duodenum to rectum) 8 h after administration of the marker to control and heat-stressed animals. Results indicated a reduced transit time for the stressed group. These ®ndings corroborate the initial hypothesis that an out¯ow of resistant organisms moves from the upper tract (ileum and caecum) to the lower tract (colon and rectum).

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Fluctuations in Escherichia coli O‐serotypes in Pigs Throughout Life in the Presence and Absence of Antibiotic Treatment

Cited by 18 publications

References 13 publications

Effects of cold stress on the antimicrobial drug resistance of Escherichia coli of the intestinal flora of swine

Effects of cold stress on the antimicrobial drug resistance of Escherichia coli of the intestinal flora of swine

Effects of cold stress on the antimicrobial drug resistance ofEscherichia coliof the intestinal flora of swine

Effects of heat stress on the antimicrobial drug resistance of Escherichia coli of the intestinal flora of swine

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