Distribution of serotypes and patterns of antimicrobial resistance among commensal Streptococcus pneumoniae in nine European countries.

BACKGROUND: Streptococcus pneumoniae is a commensal of the human upper respiratory tract and a major cause of morbidity and mortality worldwide. This paper presents the distribution of serotypes and antimicrobial resistance in commensal S. pneumoniae strains cultured from healthy carriers older than four years of age in nine European countries. METHODS: Nasal swabs from healthy persons (age between 4 and 107 years old) were obtained by general practitioners from each country from November 2010 to August 2011. Swabs were cultured for S. pneumoniae using a standardized protocol. Antibiotic resistance was determined for isolated S. pneumoniae by broth microdilution. Capsular sequencing typing was used to identify serotypes, followed by serotype-specific PCR assays in case of ambiguous results. RESULTS: Thirty-two thousand one hundred sixty-one nasal swabs were collected from which 937 S. pneumoniae were isolated. A large variation in serotype distribution and antimicrobial resistant serotypes across the participating countries was observed. Pneumococcal vaccination was associated with a higher risk of pneumococcal colonization and antimicrobial resistance independently of country and vaccine used, either conjugate vaccine or PPV 23). CONCLUSIONS: Serotype 11A was the most common in carriage followed by serotypes 23A and 19A. The serotypes showing the highest resistance to penicillin were 14 followed by 19A. Serotype 15A showed the highest proportion of multidrug resistance.

Evaluation of phenotypic and molecular methods for identification of Streptococcus pneumoniae.

AIM: The objective of this study is to compare various Streptococcus pneumoniae identification methods. MATERIALS & METHODS: In total, 1371 putative S. pneumoniae isolates were tested with three phenotypic methods and a molecular-based method targeting a virulence factor (CpsA). We assessed the sensitivity and the specificity of each method and widely used S. pneumoniae identification algorithm. RESULTS: None of the methods or the identification algorithm used separately was able to correctly identify all S. pneumoniae isolates. Furthermore, a high rate of optochin resistance was found. CONCLUSIONS: We demonstrated the failure of the current S. pneumoniae identification methods and optochin susceptibility-based algorithm. In addition, the high rate of optochin resistance might justify the necessity of a close monitoring of optochin susceptibility.

Prevalence and antibiotic resistance of commensal Streptococcus pneumoniae in nine European countries.

The human microbiota represents an important reservoir of antibiotic resistance. Moreover, the majority of antibiotics are prescribed in primary care. For this reason, we assessed the prevalence and antibiotic resistance of nasal carriage strains of Streptococcus pneumoniae, the most prevalent bacterial causative agent of community-acquired respiratory tract infections, in outpatients in nine European countries. Nasal swabs were collected between October 2010 and May 2011, from 32,770 patients, recruited by general practices in nine European countries. Overall prevalence of S. pneumoniae nasal carriage in the nine countries was 2.9%. The carriage was higher in men (3.7%) than in women (2.7%). Children (4-9 years) had a higher carriage prevalence (27.2%) compared with those older than 10 years (1.9%). The highest resistance observed was to cefaclor. The highest prevalence of multidrug resistance was found in Spain and the lowest prevalence was observed in Sweden.