Nasopharyngeal colonization and penicillin resistance among pneumococcal strains: a worldwide 2004 update

Surveillance of nasopharyngeal pneumococcus has proven to be a valuable tool for the monitoring of antibiotic resistance. We reviewed the latest information on colonization rate and penicillin resistance by making a MEDLINE search, using the terms "nasopharyngeal carriage" and "Streptococcus pneumoniae". Out of 225 articles found, data from 109 recent publications (89% from 1996-2003) were analyzed. Data were reported from 41 countries of six continents. Individuals under the age of five (64.3%) or 10 years (85.7%) were enrolled, including children attending day-care centers (32.1%) or orphanages (3.6%), and healthy individuals (78.6%) or sick patients (43.6%); biological samples were collected mainly by nasopharyngeal swabs (89.3%). The highest colonization rates were reported from Africa (85-87.2%), where several authors did not find high rates of penicillin resistance. On the other hand, studies conducted in North and Central America reported high-level penicillin resistance at rates of approximately 20-30%. Great variation in the rates of pneumococcal colonization and penicillin resistance were observed within regions or continents. There were also considerable differences in similar populations located in different areas of the same country. Data regarding pneumococcal colonization and penicillin resistance are not available from most countries. We also examined the use of antibiotics to treat pneumococcal infections.