In selecting antimicrobial agents for oral infections, antimicrobial agents are determined taking into account presumed pathogenic bacteria, inflammation severity, and backgrounds of patients such as underlying disease. When the infections are treated, effectiveness of the treatment is increased by examining pharmacokinetics (PK) and pharmacodynamics (PD) such as in vivo absorption, distribution, metabolism and excretion of the antimicrobial agents, and by giving antimicrobial chemotherapy based on the PK-PD theory.
The oral infections are polymicrobial infections with anaerobes and aerobes. The most common species isolated are Prevotella, Peptostreptococcus and Streptococcus.
In severe oral infections, beta-lactamase producing bacteria are often involved, and the frequency to detect anaerobes increases with severity of the cases. Beta-lactamase in Prevotella degrades penicillin derivatives and cephem derivatives including the third generation. Anti-inflammatory treatment to decrease the number of pathogenic bacteria in infection foci and appropriate antimicrobial chemotherapy based on the PK-PD theory improve therapeutic efficacy and inhibit emergence of drug resistant bacteria.