Streptococcus pneumoniae causes many clinical syndromes, depending on the site of infection (e.g., acute otitis media, pneumonia, bacteremia, or meningitis).
Laboratory Criteria For Diagnosis
- Isolation of S. pneumoniae from a normally sterile site (e.g., blood, cerebrospinal fluid, or, less commonly, joint, pleural, or pericardial fluid), AND
- "Nonsusceptible" isolate (i.e., intermediate- or high-level resistance of the S. pneumoniae isolate to at least one antimicrobial agent currently approved for use in treating pneumococcal infection*1,2
A clinically compatible case caused by laboratory-confirmed culture of S. pneumoniae identified as "nonsusceptible" (i.e., an oxacillin zone size of less than 20 mm) when oxacillin screening is the only method of antimicrobial susceptibility testing performed
A clinically compatible case that is laboratory confirmed
*Resistance defined by National Committee for Clinical Laboratory Standards (NCCLS)-approved methods and NCCLS-approved interpretive minimum inhibitory concentration (MIC) standards (µg/mL) for S. pneumoniae. NCCLS recommends that all invasive S. pneumoniae isolates found to be "possibly resistant" to beta-lactams (i.e., an oxacillin zone size of less than 20 mm) by oxacillin screening should undergo further susceptibility testing by using a quantitative MIC method acceptable for penicillin, extended-spectrum cephalosporins, and other drugs as clinically indicated.1
- National Committee for Clinical Laboratory Standards (NCCLS). Performance standards for antimicrobial susceptibility testing. Villanova, PA: National Committee for Clinical Laboratory Standards, 1994;14(16); NCCLS document M100-S5.
- CDC. Defining the public health impact of drug-resistant Streptococcus pneumoniae: Report of a working group. MMWR 1996;45(No. RR-1).