Antimicrobial susceptibility testing in the office laboratory.

The performance, quality control and interpretation of antimicrobial susceptibility tests are a complex affair. Fortunately empiric oral antimicrobial therapy usually suffices for most nonsystemic pediatric bacterial infections which would ordinarily be treated on an outpatient basis (e.g. otitis media, streptococcal pharyngitis, pyoderma, UTI). Common pediatric pathogens such as H. influenzae and S. pneumoniae require uncommon expertise and complex systems for appropriate susceptibility testing. Direct susceptibility testing of urine specimens is the only current antimicrobial test that can be practically and reliable performed in most office laboratories. Access to a reliable reference laboratory with appropriate quality control systems is essential for other antimicrobial susceptibility testing needs.