JAC Advance Access originally published online on September 26, 2008
Journal of Antimicrobial Chemotherapy 2008 62(6):1430-1433; doi:10.1093/jac/dkn413
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Original research |
Has the licensing of respiratory quinolones for adults and the 7-valent pneumococcal conjugate vaccine (PCV-7) for children had herd effects with respect to antimicrobial non-susceptibility in invasive Streptococcus pneumoniae?
1 Spanish National Reference Pneumococcal Laboratory, Instituto de Salud Carlos III, ctra. Majadahonda-Pozuelo Km. 2, 28220 Majadahonda, Madrid, Spain 2 Microbiology Department, School of Medicine, Univ. Complutense, Avda. Complutense s/n, 28040 Madrid, Spain 3 Grana Datos SL, c/ Demetrio de la Guerra 4, 28223 Pozuelo de Alarcón, Madrid, Spain 4 Medical Department, Wyeth Farma S.A., N-I Km. 23, Desvío Algete Km. 1, 28700 San Sebastián de los Reyes, Madrid, Spain
Received 9 June 2008; returned 20 July 2008; revised 18 August 2008; accepted 9 September 2008
* Corresponding author. Tel: +34-91-3941505; Fax: +34-91-3941511; E-mail: laguilar{at}med.ucm.es
Objectives: The aim of the study was to analyse the evolution of antibiotic non-susceptibility in Spanish invasive Streptococcus pneumoniae after licensure of respiratory-quinolones for adults and 7-valent pneumococcal conjugate vaccine (PCV-7) for immunization of children.
Methods: All invasive pneumococci received in the Reference Laboratory (January 2000–August 2007; n = 12 957 isolates) were serotyped, and susceptibility to penicillin/erythromycin/levofloxacin was determined. Antibiotic consumption and PCV-7 doses/year were provided by IMS and the manufacturer, respectively.
Results: In 2000–07, PCV-7 distribution (doses/1000 inhabitants 
59 months age/year) increased from 0.0 to 411.90, and antibiotic consumption (DDD/1000 inhabitants/day) was maintained for β-lactams (
16), decreased for macrolides (from 4.4 to 2.7) and increased for respiratory fluoroquinolones (from 0.3 to 2.7). The increase in PCV-7 distribution correlated with a decrease in PCV-7 serotypes prevalence among invasive isolates in children (r = –0.976; P < 0.001) and adults (r = –0.905; P = 0.002). This decrease in PCV-7 serotypes correlated with a decrease in penicillin non-susceptibility in children (r = 0.929; P < 0.001) and adults (r = 0.905; P = 0.002) and with erythromycin non-susceptibility in children (r = 0.833; P = 0.010). Penicillin/erythromycin non-susceptibility in 2000 was significantly higher in paediatric versus adult isolates (penicillin: 51.4% versus 29.2%; erythromycin: 39.5% versus 20.4%), but similar in 2006–07 (20% to 24%). The increase in respiratory quinolones consumption correlated with the increase in levofloxacin non-susceptibility in adults (r = 0.926; P = 0.008) but not in children, with different non-susceptibility rates in 2007 (1.6% versus 0.0%; P = 0.013).
Conclusions: This ecological analysis suggests that PCV-7 vaccination in children had a herd effect in adults, but consumption of respiratory quinolones in adults had no effect on pneumococcal susceptibility to levofloxacin in children. Penicillin/erythromycin non-susceptibility decreased along the studied period among paediatric invasive S. pneumoniae isolates to a level similar to that seen in adults.
Keywords: antibiotic consumption , PCV-7 distribution , pneumococcal resistances , vaccination