Objectives:

Establish the susceptibility pattern of S. pneumoniae and the beta-lactamase production of H. influenzae and M. catarrhalis isolated from patients with community-acquired respiratory tract infections through an international surveillance study.

Methods:

During 2002, six centres in Brazil collected bacterial isolates from patients with one of the following infections: pneumonia, acute bacterial exacerbation of chronic bronchitis, acute exacerbation of chronic obstructive airways disease, acute/chronic sinusitis, pharyngitis, and acute otitis media. S. pneumoniae isolates were tested against penicillin, amoxacillin, amoxacillin/clavulanic acid, cefuroxime axetil, cefaclor, and azithromycin. Minimal inhibitory concentrations (MIC) were determined by broth microdilution in a central lab. Interpretative criteria used were those described by NCCLS documents M100-S13. H. influenzae and M. catarrhalis isolates were tested for beta-lactamase production by chromogenic cephalosporin method (Cefinase[R]).

Results:

There were 687 isolates as follows: S. pneumoniae (35%); H. influenzae (31%); S. aureus (15%); S. pyogenes (12%); M. catarrhalis (7%). Among H. influenzae and M. catarrhalis 10 and 100% were beta-lactamase producers, respectively. Among S. pneumoniae 67.6% were susceptible (S), 17.2% were intermediate resistant (I), and 15.1% were fully resistant (R) to penicillin.

Conclusions:

The production of beta-lactamase among M. catharralis and H. influenzae strains was similar to that found by other local studies. The prevalence of penicillin resistant pneumococci has increased dramatically compared with previous local data, suggesting, among other factors, a possible methodological issues. Empiric therapy with penicillins alone or in low dose should be avoided in this population.