Case of Antibiotic-Resistant Swine Dysentery

UK - The latest Monthly Disease Surveillance Report (August 2008) from the Veterinary Laboratories Agency (VLA) describes three cases of swine dysentery. The first caused the deaths of 30 pigs, and another was caused by a bacterial strain resistant to three antibiotics commonly used to control the disease.
calendar icon 22 October 2008
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An investigation was carried out into an outbreak of swine dysentery in an indoor all-in all-out 1,800 pig finisher unit receiving pigs at approximately 12 weeks old from three sources. Approximately 100 of 460 pigs were affected, with 30 dying over a week. Two dead pigs were submitted for post-mortem examination which revealed severe colitis in both. Brachyspira hyodysenteriae was identified by FAT, culture and PCR. The unit had no recent history of swine dysentery and it was suspected that the source of infection was a finishing unit approximately half a mile away.

In another case, faeces samples were submitted as part of an investigation into increased incidence of clinical signs of bloody mucoid scour affecting approximately 20 per cent of 8-week-old grower pigs on a 100-sow farrow-to-finish indoor unit, despite in-feed medication with tiamulin at 100ppm. The unit was known to have swine dysentery. Tylosin had been used in-feed in the past with limited success. Testing for minimum inhibitory concentration (MIC) of antibiotics revealed values of >200µg/ml for tylosin (no inhibition), 32-64µg/ml for tiamulin (acceptable control range 0.062-0.125µg/ml) and lincomycin 200µg/ml (acceptable control range 25-50µg/ml). The results suggest full or partial resistance to three commonly used antimicrobials for the treatment of swine dysentery.

Sutton Bonnington also diagnosed the condition as the cause of colitis and dysentery affecting adult sows. No further history was provided. Brachyspira hyodysenteriae was confirmed following isolation of the organism on specific culture media along with a positive FAT result.

Further Reading

- You can view the full report by clicking here.
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