[Antibiotic resistance of S. pneumoniae and H. influenzae strains isolated from patients with community acquired respiratory tract infections. BACTRO multicenter, multidisciplinary study].

UNLABELLED: Community respiratory tract infections are common in clinical practice. Antimicrobial treatment should be promptly administered and guided by a probabilistic approach according to the clinical presentation and local patterns of bacterial resistance. Bacterial resistance is widespread, with large geographical variations related to behaviors in antibiotics prescription. S. pneumoniae and H. influenzae are the most frequent pathogens responsible for respiratory tract infections etiology.

METHODS: We assessed the antibiotics susceptibility of S. pneumoniae and H. influenzae strains isolated from patients with community respiratory tract infections, prospectively enrolled over a period of 3 consecutive years, by determining the MIC. Analysis was performed using both cutoffs provided by European Committee on Antimicrobial Susceptibility testing (EUCAST) and CLSI. Consequently we evaluated the influence of different factors associated with the development of bacterial resistance.

RESULTS: We analyzed 293 S. pneumoniae strains and 265 H. influenzae strains isolated during 1999-2001, mainly from sputum (68.3% and 74.9% respectively of total isolates). We observed a high proportion of S. pneumoniae resistant to penicillin (6.1% resistant and 48.5% with intermediate susceptibility) and to erythromycin (39% resistant strains). H. influenzae strains were resistant to amoxicillin in 26% of cases and the presence of betalactamase was certified in 13% of tested isolates; 18.3% of H. influenzae strains were resistant to amoxicillin through specific mechanisms other than by producing betalactamase. Other antibiotic resistances were assessed.

CONCLUSIONS: In Romania clinician must consider the high prevalence of antibiotic resistance, particulary of S. pneumoniae to macrolides and beta-lactams (thus requiring the use of high doses of betalactams) and the high proportion of beta-lactamase producing H. influenzae.