Past administration of β-lactam antibiotics and increase in the emergence of β-lactamase-producing bacteria in patients with orofacial odontogenic infections

Objective. The purpose of this study was to determine the current status of beta-lactamase-producing bacteria in orofacial odontogenic infections. Study design. Microbiologic data regarding purulent exudate from ill cases with orofacial odontogenic infections were analyzed in relation to the past administration of beta-lactams. Results. beta-lactamase-producing bacteria were isolated more frequently from the beta-lactam-administered group (38.5%) than from the beta-lactam-nonadministered group (10.9%; P < .005), and they were isolated more frequently as the duration of administration increased. The predominant bacteria isolated included Prevotella (the most frequent isolate), viridans streptococci, Peptostreptococcus, and Fusobacterium, and 7.1% of total isolates produced beta-lactamase. Penicillin and cefazolin worked well with beta-lactamase-nonproducing Prevotella but were remarkably affected by beta-lactamase-producing Prevotella. Cefmetazole, sulbactam/cefoperazone, and imipenem worked well against both types of Prevotella, Conclusions. beta-lactams are still suitable for the first antimicrobial therapy in the treatment of these infections. However, because past beta-lactam administration increases the emergence of beta-lactamase-producing bacteria, beta-lactamase-stable antibiotics should be prescribed to patients with unresolved infections who have received beta-lactams.