THE ASSOCIATION OF ERYTHROMYCIN ETHYLSUCCINATE WITH ACUTE COLITIS IN HORSES IN SWEDEN

In Sweden there are several reports of mares developing acute colitis while their foals were being treated orally for Rhodococcus equi pneum onia with the combination of erythromycin and rifampicin. In this stud y 6 adult horses were given low oral dosages of these antibiotics, sin gly or in combination, Within 3 days post administration of erythromyc in, in one case in combination with rifampicin, 2 horses developed sev ere colitis (one fatal), Clostridium difficile was isolated from one o f the horses, whereas no specific pathogens were isolated from the oth er, Both horses had typical changes in blood parameters seen in acute colitis, Clostridium difficile was also isolated from the faeces of a third horse given an even lower dosage of erythromycin in combination with rifampicin, This horse developed very mild clinical symptoms and recovered spontaneously, In the fourth horse given erythromycin only, very high numbers of Clostridium perfringens were isolated, The horses given rifampicin only did not develop any clinical symptoms and there were no major changes in their faecal flora. In conclusion, it has be en demonstrated that low dosages of erythromycin ethylsuccinate can in duce severe colitis in horses associated with major changes of the int estinal microflora. Clostridium difficile has been demonstrated as a p otential aetiological agent in antibiotic-induced acute colitis.