Decrease in antibiotic resistance of Streptococcus pneumoniae between 2003 and 2009 in France and changes in serotype distribution: Ongoing survey of the French Pneumococcus Surveillance Network
Résumé
Background:
The French regional pneumococcal observatories (ORP) network was created in 1995, it participates to the close monitoring of the trends in antimicrobial resistance and serotype distribution with the National Reference Centre for Pneumococci (NRCP) and the Institut de Veille Sanitaire (InVS). The aim of this survey was to assess the antibiotic resistance and the distribution of vaccine and non-vaccine serotypes in invasive pneumococcal disease (IPD) in adults and children as well in otitis in children in France in 2009.
Methods:
Antimicrobial susceptibility testing was performed on 5,194 isolates of S. pneumoniae recovered from cerebrospinal fluid (CSF), blood, middle ear fluid (MEF) and pleural fluid during the year 2009 by the 23 ORP. MICs of penicillin (P), amoxicillin (AMX) and cefotaxime (CTX) were determined by the agar dilution method and interpreted according to the Antibiotics Comity of the French Society of Microbiology breakpoints. Serotyping was performed at the NRCP with serotype-specific antisera, by latex agglutination test.
Results:
Results of susceptibility between 2003 and 2009 to P are presented in Table 1. The pneumococci with decreased susceptibility to penicillin G (PDSP) decreased significantly in all types of samples except for MEF’s isolates in children between 2007 and 2009. In the global population, the percentage of I+R (2003 vs 2009) decreased significantly for AMX (30.3% versus 9.6%) and for CTX (18.2% versus 10.5%). Strains highly resistant (MIC > 2 mg/L) remained rare: 0.4%, 1.1% and 0.2% for P, AMX and CTX respectively. The most frequent capsular types in CSF were 3, 7F, 19A, 6C, 23B for adults and 7F, 19A, 3, 33F and 15B for children. Serotypes included in the PCV-7 and PCV-13 vaccine accounted in children for 4% and 51% respectively and in adults for 12% and 48% respectively. By contrast, the serotype 19A remained highly predominant (80%) among MEF isolates.
Conclusions:
We observed a significant decrease of PDSP between 2003 and 2009 (50.2 to 33.0%). The decrease coincided with the introduction of PCV7 and with a general reduction in levels of antibiotic consumption in France. This continuous survey is necessary to underline modification in serotype distribution in France after PVC13 introduction (June 2010).