Microaerophilic streptococci as a significant pathogen: a twelve-year review

One hundred twenty three microaerophilic streptococci (MS) were isolated from 4,603 specimens submitted for the identification of anaerobic bacteria over the course of 12 years. The MS included 16 Streptococcus constellatus, 43 Streptococcus intermedius and 21 Gemella morbillorum. A total of 81 MS isolates (66%) identified from 75 patients were considered to cause infection. Predisposing or underlying conditions were noted in 48 (64%) patients. The most common conditions were previous surgery (15 instances), trauma (10), diabetes (9), immunodeficiency (6), malignancy, and prosthetic device (5 each). MS were the only bacterial isolates in 23 instances. Mixed infection was encountered in 52 (69%) patients, where the number of isolates varied between two and five (average 2.7). The organisms most commonly isolated with MS were anaerobic cocci, Bacteroides sp. and Enterobacteriaceae; their recovery varied at different sites. Significant infections caused by MS were associated with abscess (29 instances), sinuses (7), obstetrical and gynecological (OBG), chest and wounds (6 each), abdominal (5), and biliary infection (4). Antimicrobial therapy as administered to 71 patients; for 43 patients, in conjunction with surgical drainage or correction. Surgical drainage alone was performed in three patients. Four patients (5%) died. These data illustrate that MS can occasionally be associated with serious infection.