Staphylococcus intermedius: clinical presentation of a new human dog bite pathogen.
Staphylococcus intermedius is a Gram-positive, coagulase-positive coccus that can be distinguished from Staphylococcus aureus by routine microbiological testing. Whereas S intermedius is recognized as flora and pathogen of dogs, it has never been isolated from human infections. We hypothesized that S intermedius may cause human dog bite wound infections and that it has been previously misidentified as S aureus. Fourteen isolates from clinically infected dog bite wounds that were originally identified as S aureus were subjected to further testing; three (22%) were found to be S intermedius. The clinical and microbiological characteristics of these three S intermedius cases are described. All three patients were nonimmunocompromised persons seen within 24 hours for bites on the upper extremity. All patients developed cellulitis within one to three days. All S intermedius isolates were distinguished from S aureus by the lack of acetoin production and by the presence of beta-galactosidase activity. S intermedius was susceptible to a wide range of antibiotics; one isolate was resistant to penicillin. Two patients were treated with penicillin, one with amoxicillin-clavulanate, and all were clinically cured. These are the first three reported human infections involving S intermedius. Further study is necessary to define its clinical importance as a potential human pathogen.
Talan
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UCLA School of Medicine, Department of Emergency Medicine, Sylmar, California 91342.
Goldstein
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EJ
Staatz
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Overturf
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D000328:Adult; D000818:Animals; D001733:Bites and Stings / Q000150:complications*; D004285:Dogs; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013203:Staphylococcal Infections / Q000382:microbiology; D013210:Staphylococcus / Q000145:classification / Q000302:isolation & purification; D014946:Wound Infection / Q000209:etiology* / Q000382:microbiology