A nationwide multicenter susceptibility surveillance study which included 1,684 Streptococcus pneumoniae and 2,039 S. pyogenes isolates was carried out over 1 year in order to assess the current resistance patterns for the two most important gram-positive microorganisms responsible for community-acquired infections in Spain. Susceptibility testing was done by a broth microdilution method according to National Committee for Clinical Laboratory Standards M100-S10 interpretative criteria. For S. pneumoniae, the prevalences of highly resistant strains were 5% for amoxicillin and amoxicillin-clavulanic acid; 7% for cefotaxime; 22% for penicillin; 31% for cefuroxime; 35% for erythromycin, clarithromycin, and azithromycin; and 42% for cefaclor. For S. pyogenes, the prevalence of erythromycin resistance was 20%. Efflux was encountered in 90% of S. pyogenes and 5% of S. pneumoniae isolates that exhibited erythromycin resistance. Erythromycin resistance was associated with clarithromycin and azithromycin in both species, regardless of phenotype. Despite the different nature of the mechanisms of resistance, a positive correlation (r ‫؍‬ 0.612) between the two species in the prevalence of erythromycin resistance was found in site-by-site comparisons, suggesting some kind of link with antibiotic consumption. Regarding ciprofloxacin, the MIC was >4 g/ml for 7% of S. pneumoniae and 3.5% of S. pyogenes isolates. Ciprofloxacin resistance (MIC, >4 g/ml) was significantly (P < 0.05) associated with macrolide resistance in both S. pyogenes and S. pneumoniae and with penicillin nonsusceptibility in S. pneumoniae.

A multicenter susceptibility surveillance (the S.A.U.C.E. project) including 2,721 Streptococcus pneumoniae, 3,174 Streptococcus pyogenes, and 2,645 Haemophilus influenzae consecutive isolates was carried out in 25 hospitals all over Spain from November 2001 to October 2002 to evaluate the current epidemiology of resistance of the main bacteria involved in community-acquired respiratory tract infections. Susceptibility testing was performed in a single centralized laboratory by a broth microdilution method. The prevalence of resistant S. pneumoniae strains was 0.4% for cefotaxime, 4.4% for amoxicillin and amoxicillin-clavulanic acid, 25.6% for cefuroxime-axetil, 34.5% for erythromycin, clarithromycin, and azithromycin, and 36.0% for cefaclor. Phenotypes of resistance to erythromycin were MLS B (macrolide-lincosamide-streptogramin B) in 89.9% (gene ermB) and M (macrolide) in 9.7% of cases (gene mefA). No strain harbored both genes simultaneously. Serotypes 19, 6, 23, 14, and 3 were the most prevalent, accounting for 54.6% of the total isolates. Resistance to macrolides seems to be the most alarming point, since among penicillin-susceptible isolates it reached 15.1% compared to 55.8% among penicillin-resistant strains. Geographically, a number of regions had rates of erythromycin resistance above 40% (even higher in children). Resistance to erythromycin was also high in S. pyogenes isolates: mean regional 33.2%, beta-lactamase-producing H. influenzae were 20%, whereas 4.4% had a beta-lactamase-negative, ampicillin-resistant phenotype. We highlight the importance of different geographical frequencies of coresistance (associations of resistance to different drugs within the same species) and coupled resistance (association of resistance between different species) probably resulting from different local coselective events.Surveillance of antimicrobial resistance should be considered an important tool helping clinicians tailor empirical prescriptions for common infectious diseases. Surveillance data also serve as sentinel checkpoints for emerging phenotypes of resistance and enable performance of studies aiming at characterizing molecular resistance determinants alongside the possibility of tracking the genotypic or clonal relatedness of the isolates harboring the resistance traits detected (4). Besides, when coupled with appropriate data of antimicrobial consumption, they contribute to the understanding of the complex dynamics of the pharmacoepidemiology of resistance. Ideally, they should also serve to assess the impact of measures implemented in response to resistance warnings.The most prevalent bacteria causing community-acquired respiratory tract infections are Streptococcus pneumoniae, Streptococcus pyogenes, and Haemophilus influenzae. In all of

The study presented here determined the relationship between antimicrobial resistance in Streptococcus pneumoniae and the use of antimicrobial agents in 15 different European countries. Pneumococcal isolates (n = 1974) recovered from patients with community-acquired respiratory tract infections during the winter of 2004-2005 in 15 European countries were characterized. The overall percentages of isolates demonstrating intermediate or complete resistance to penicillin, erythromycin, tetracycline, trimethoprim-sulfamethoxazole (TMP-SMX) and ciprofloxacin were 24, 24.6, 19.8, 26.7 and 2%, respectively, as determined using the broth microdilution MIC method recommended by the Clinical and Laboratory Standards Institute. The overall and mean antimicrobial consumption levels (ACL)--i.e., the defined daily doses per 1,000 inhabitants per day--were obtained from the European Surveillance of Antimicrobial Consumption project for each of the 15 countries for the years 1998-2004. Using linear regression analysis, the mean annual ACL for beta-lactams, macrolides, tetracyclines, TMP-SMX and fluoroquinolones in each country was compared to the country-specific resistance rates determined in 2004-2005. The rate of overall antimicrobial use in all 15 European countries was significantly associated with antimicrobial resistance in S. pneumoniae. There was variation among the different antimicrobial classes as drivers of resistance, with beta-lactams having the strongest association.

A nationwide multicenter susceptibility surveillance study (Susceptibility to the Antimicrobials Used in the Community in España [SAUCE] project), SAUCE-4, including 2,559 Streptococcus pneumoniae, 2,287 Streptococcus pyogenes, and 2,736 Haemophilus influenzae isolates was carried out from May 2006 to June 2007 in 34 Spanish hospitals. Then, the results from SAUCE-4 were compared to those from all three previous SAUCE studies carried out in 1996-1997, 1998-1999, and 2001-2002 to assess the temporal trends in resistance and the phenotypes of resistance over the 11-year period. In SAUCE-4, on the basis of the CLSI breakpoints, penicillin (parenteral, nonmeningitis breakpoint) and cefotaxime were the antimicrobials that were the most active against S. pneumoniae (99.8% and 99.6%, respectively). Only 0.9% of isolates had a penicillin MIC of >2 g/ml. In S. pyogenes, nonsusceptibility to erythromycin was observed in 19.4% of isolates. Among the H. influenzae isolates, a ␤-lactamase-positive prevalence of 15.7% was found. A statistically significant temporal decreasing trend over the 11-year period was observed for nonsusceptibility (from 60.0% to 22.9%) and resistance (from 36.5% to 0.9%) to penicillin and for the proportion of erythromycin-resistant isolates of S. pneumoniae of the macrolide-lincosamide-streptogramin B (MLS B ) phenotype (from 98.4% to 81.3%). A similar trend was observed for the prevalence of ampicillin resistance (from 37.6% to 16.1%), ␤-lactamase production (from 25.7% to 15.7%), and ␤-lactamase-negative ampicillin resistance (BLNAR) in H. influenzae (from 13.5% to 0.7%). Among erythromycin-resistant isolates of S. pyogenes, a significant increasing trend in the prevalence of MLS B was observed (from 7.0% to 35.5%). SAUCE-4 confirms a generalized decline in the resistance of the main respiratory pathogens to the antimicrobials as well as a shift in their resistance phenotypes.

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