Our aim was to investigate bacteremia caused by surgical extraction of partly erupted mandibular third molars. From 16 young adults, bacterial samples were taken from the third-molar pericoronal pocket and post-operatively from the extraction socket, and blood samples were drawn from the ante-cubital vein up to 30 min after surgery. Of the subjects, 88% had detectable bacteremia-50% 1 min after the incision, 44% immediately after extraction. The respective percentages at 10, 15, and 30 min were 44%, 25%, and 13%. Blood cultures contained 31 species (74% anaerobes), with 3.9 +/- 2.6 species isolated per subject. Most prevalent were the anaerobes Prevotella, Eubacterium, and Peptostreptococcus sp. and the aerobes viridans-group streptococci and Streptococcus milleri group. Any species found in the blood was also isolated from the mouth, from 93% of the pericoronal pockets and from 43% of the extraction sockets. Surgical dental extraction clearly causes bacteremia of a high frequency and lasting longer than thus far assumed.

The frequency of beta-lactamase production by oral pigmented Prevotella species isolated from 23 healthy young children and the minimal inhibitory concentrations (MICs) for 186 available beta-lactamase-positive isolates were examined by using the chromogenic cephalosporin disk test (AB BIODISK, Solna, Sweden) and the Etest (AB BIODISK) and/or the agar dilution method of the National Committee for Clinical Laboratory Standards (Villanova, PA, USA), respectively. beta-Lactamase-positive Prevotella melaninogenica strains were isolated from all children, and more than two-thirds of the Prevotella denticola and Prevotella loescheii strains isolated from the children were beta-lactamase-positive. The beta-lactamase-producing Prevotella intermedia group consisted of Prevotella nigrescens and the P. intermedia/ P. nigrescens-like organism (PINLO); P. intermedia was not found. Only two P. nigrescens isolates but most of the PINLO isolates produced beta-lactamase. The MICs for beta-lactamase-producing strains varied between 0.38 and 64 micrograms/mL. beta-Lactamase production by oral pigmented Prevotella species colonizing young children is already frequent. The phenomenon should be taken into account in the treatment of pediatric anaerobic infections of oral origin.