Abstract
Serratia marcescens was isolated in pure culture from cases of septic abortion in 4 cows on one farm and 10 buffaloes on two other farms. A reddish vaginal discharge was observed after abortion in all animals and in the internal organs of the aborted fetuses. All but two of the isolates produced prodigiosin, and two of the isolates from buffaloes were atypical in that they fermented raffinose. O-serological, bacteriophage and bacteriocin typing revealed four different strains. All cows were infected by the same strain, and this strain was also isolated from the semen of a breeding bull on the same farm. In another farm a strain of serotype O 14 was isolated from 6 of 10 buffaloes, and two other distinct strains were isolated from the remainder. The strain from the cattle was sensitive to gentamicin and so were two of the buffalo isolates. The infected cows were treated with intra-uterine gentamicin and the organism disappeared from cervical mucus after 3 days. Each animal after abortion showed a raised titre of agglutinating antibody to their respective isolate. A survey of 1172 healthy buffaloes and cattle gave an incidence of 1.8% with raised titres towards S. marcescens.