A case study of Streptococcus group G infection in a dairy herd.
In this paper an outbreak of bovine mastitis in a dairy herd caused by Streptococcus group G is described. Initial identification of the organism as Streptococcus agalactiae was based upon hemolysis, esculin reaction, and CAMP reaction observed on blood agar used for bulk milk analysis. Initial therapy with a penicillin-containing, lactating cow product cured 24.4% of all streptococcal infections. Definitive serogrouping by coagglutination determined that the majority of infections were due to a weakly-hemolytic, esculin-negative Streptococcus group G. Treatment with a cephalosporin, lactating cow product was only moderately successful (54.9%). Dry-cow therapy with 300 mg cephalosporin eliminated 69.5% of refractory infections. Animals remaining infected following dry-cow therapy were culled. Histopathological study of parenchymal tissue in the lower portion of infected quarters revealed mild damage and slight involutionary changes, whereas, deep parenchymal areas appeared relatively unaffected.
D000818:Animals; D002417:Cattle; D002511:Cephalosporins / Q000627:therapeutic use; D003612:Dairying; D004196:Disease Outbreaks / Q000662:veterinary; D005260:Female; D007774:Lactation; D008321:Mammary Glands, Animal / Q000382:microbiology / Q000473:pathology; D008414:Mastitis, Bovine / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology; D008892:Milk / Q000382:microbiology; D011247:Pregnancy; D012703:Serotyping; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D013291:Streptococcus / Q000145:classification / Q000302:isolation & purification*; D013292:Streptococcus agalactiae / Q000302:isolation & purification
D002511:Cephalosporins