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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, GA, 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 100000 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 100000 in 1994 to 9.3 per 100 000 in 1999, fell to 2.9 per 100000 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. [ABSTRACT FROM AUTHOR]

Background: Five of seven serotypes in the pneumococcal conjugate vaccine, introduced for infants in the United States in 2000, are responsible for most penicillin-resistant infections. We examined the effect of this vaccine on invasive disease caused by resistant strains. Methods: We used laboratory-based data from Active Bacterial Core surveillance to measure disease caused by antibiotic-nonsusceptible pneumococci from 1996 through 2004. Cases of invasive disease, defined as disease caused by pneumococci isolated from a normally sterile site, were identified in eight surveillance areas. Isolates underwent serotyping and susceptibility testing. Results: Rates of invasive disease caused by penicillin-nonsusceptible strains and strains not susceptible to multiple antibiotics peaked in 1999 and decreased by 2004, from 6.3 to 2.7 cases per 100,000 (a decline of 57 percent; 95 percent confidence interval, 55 to 58 percent) and from 4.1 to 1.7 cases per 100,000 (a decline of 59 percent; 95 percent confidence interval, 58 to 60 percent), respectively. Among children under two years of age, disease caused by penicillin-nonsusceptible strains decreased from 70.3 to 13.1 cases per 100,000 (a decline of 81 percent; 95 percent confidence interval, 80 to 82 percent). Among persons 65 years of age or older, disease caused by penicillin-nonsusceptible strains decreased from 16.4 to 8.4 cases per 100,000 (a decline of 49 percent). Rates of resistant disease caused by vaccine serotypes fell 87 percent. An increase was seen in disease caused by serotype 19A, a serotype not included in the vaccine (from 2.0 to 8.3 per 100,000 among children under two years of age). Conclusions: The rate of antibiotic-resistant invasive pneumococcal infections decreased in young children and older persons after the introduction of the conjugate vaccine. There was an increase in infections caused by serotypes not included in the vaccine. N Engl J Med 2006;354:1455-63. [ABSTRACT FROM AUTHOR]