Carriage of respiratory tract pathogens and molecular epidemiology of Streptococcus pneumoniae colonization in healthy children attending day care centers in Lisbon, Portugal

In an effort to establish the rate of carriage of antibiotic resistant resp iratory pathogens in children attending urban day care centers (DCC) in Por tugal, seven DCC in Lisbon were selected for determining the rate of nasoph aryngeal colonization of children between the ages of 6 months to 6 years b y Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhal is, Of the 586 children studied between January and March 1996, 47% carried S, pneumoniae, 72% H, influenzae, and 54% M, catarrhalis, Twenty-four perc ent of the pneumococci had reduced susceptibility to penicillin, and most o f these belonged to serogroups 19, 23, 14, and 6, An additional 19% were fu lly susceptible to penicillin but showed decreased susceptibility to other antimicrobials, These isolates expressed serogroups 6, 11, 14, 18, 19, and 34, The majority (96%) of M, catarrhalis and 20% of H, influenzae were peni cillin resistant due to the production of beta-lactamases, Recent antimicro bial use was associated with carriage of penicillin non-susceptible pneumoc occi and beta-lactamase producing H, influenzae (p < 0.05), Individual DCC differed substantially from one another in their rates of carriage of antib iotic resistant H, influenzae and S, pneumoniae, Characterization of antibi otic resistant S. pneumoniae isolates by molecular fingerprinting technique s showed that each DCC had a unique microbiological profile, suggesting lit tle, if any, exchange of the resistant microbial flora among them. An excep tion to this was the presence of isolates belonging to two internationally spread epidemic clones: the multiresistant Spanish/USA clone expressing ser otype 23F, and the penicillin and sulfamethoxazole-trimethoprim resistant F rench/Spanish clone (serotype 14) which were detected in four and three DCC , respectively.