Dog-associated bacterial infections in humans: isolates submitted to an Australian reference laboratory, 1981-1992

Over the period 1981-92, 32 bacterial isolates were referred to the Microbiological Diagnostic Unit from infected dog-bite wounds and 10 isolates were submitted from blood cultures after dog bites or close contact with dogs. The isolates from the bite wounds were identified, or confirmed, as Pasteurella multocida (11 isolates), Pasteurella dagmatis (3), CDC group M-5 (9), CDC group EF-4a (8) and Streptococcus anginosus (1). Five of the 9 patients from whom CDC group M-5 was cultured had mixed infections: 2 with P. multocida one of which also had Bacteroides sp., one with P. dagmatis, one with CDC group EF-4a and another with Bacteroides sp. Nine of the 10 blood isolates were identified as Capnocytophaga canimorsus. The remaining one of Streptobacillus moniliformis, which is typically associated with rat-bite fever, was the result of a bite from a breed of dog (greyhound) that eats rodents. Clinical notes are provided for infections caused by the more unusual bacterial isolates and their laboratory identification is described.