Incidence of macrolide resistance in Streptococcus pneumoniae after introduction of the pneumococcal conjugate vaccine:: population-based assessment

Background The prevalence of macrolide resistance in Streptococcus pneumoniae has risen in recent years after the introduction of new macrolides and their increased use. We assessed emergence of macrolide-resistant invasive S pneumoniae disease in Atlanta, CA, USA, before and after the licensing, in February 2000, of the heptavalent pneumococcal conjugate vaccine for young children. Methods Prospective population-based surveillance was used to obtain pneumococcal isolates and demographic data from patients with invasive pneumococcal disease. We calculated cumulative incidence rates for invasive pneumococcal disease for 1994-2002 using population estimates and census data from the US Census Bureau. Findings The incidence of invasive pneumococcal disease in Atlanta fell from 30.2 per 100 000 population (mean annual incidence 1994-99) to 13.1 per 100 000 in 2002 (p < 0.0001). Striking reductions were seen in children younger than 2 years (82% decrease) and in those 2-4 years (71% decrease), age-groups targeted to receive pneumococcal conjugate vaccine. Significant declines were also noted in adults aged 20-39 (54%), 40-64 (25%), and 65 years and older (39%). Macrolide resistance in invasive S pneumoniae disease in Atlanta, after increasing steadily from 4.5 per 100 000 in 1994 to 9.3 per 100 000 in 1999, fell to 2.9 per 100 000 by 2002. Reductions in disease caused by mefE-mediated and erm-mediated macrolide-resistant isolates of conjugate-vaccine serotypes 6B, 9V, 19F, and 23F, and the vaccine-associated serotype 6A were also recorded. Interpretation Vaccines can be a powerful strategy for reducing antibiotic resistance in a community.