RELATIONSHIP BETWEEN IN-VITRO SENSITIVITY OF COLIFORM PATHOGENS IN THE UDDER AND THE OUTCOME OF TREATMENT FOR CLINICAL MASTITIS

The relationship between in vitro sensitivity to antimicrobials and th e outcome of treatment was studied in 228 cows with coliform mastitis. All the cows were treated with a preparation containing sulphonamide and trimethoprim, and 197 of them were also treated with a non-steroid al anti-inflammatory drug (NSAID), The relationship between in vitro s ensitivity to sulphonamide/trimethoprim and recovery was analysed by m ultivariate logistic regression. The possible confounding effects of t reatment with an NSAID, days in lactation, parity, herd, and type of i nfecting organism were tested, Only treatment with an NSAID had a sign ificant confounding effect and was included in the final statistical m odel. The recovery rate of the 165 cows infected by coliforms that wer e sensitive to sulphonamide/trimethoprim (89.1 per cent) was higher th an that of the 63 cows infected by coliforms that were resistant to su lphonamide/trimethoprim (74.6 per cent),The odds ratio of recovery for the cases associated with organisms that were sensitive to sulphonami de/trimethoprim relative to the cases associated with organisms that w ere resistant to sulphonamide/trimethoprim was 2.75, with a 95 per cen t confidence from 1.25 to 5.85. The odds ratio of recovery for the cas es treated with an NSAID relative to the cases treated with sulphonami de/trimethoprim only was 2.76 with a 95 per cent confidence interval f rom 1.12 to 6.79.