Invasive Streptococcus pneumoniae infections in children and older adults in the north of Spain before and after the introduction of the heptavalent pneumococcal conjugate vaccine

Abstract

In the last two decades, an increasing trend in the incidence of pneumococcal disease in Europe has been reported. We investigated the effect of the use of the heptavalent pneumococcal conjugate vaccine (PCV7) in an area of northern Spain, where all recorded cases of invasive pneumococcal diseases (IPD) were included (n = 450; 91 between 1996-2007 in children aged <5 years and 359 between 1998-2007 in adults aged >64 years). All isolates were serotyped. In children, the overall IPD incidence did not significantly decrease after the introduction, in late 2001, of PCV7. However, the incidence of PCV7 serotypes significantly decreased by 137.2% from 31.59 cases/100,000 population in 1996-2001 to 13.42 in 2002-2007 (95% confidence interval [CI] -27.2 to -342.4%), as did the overall rates of penicillin resistance (from 45.6 to 18.6%) and multiresistance (from 30.3 to 11%). In older adults, the overall IPD incidence showed a non-significant increase due to non-PCV7 serotypes, which seemed to continue a previous trend in our region.

Antimicrobial Resistance among Respiratory Pathogens in Spain: Latest Data and Changes over 11 Years (1996-1997 to 2006-2007)

“…The decline in the prevalence of resistance of S. pneumoniae to penicillin and, to a lesser degree, to erythromycin is in accordance with other reports (14,16,17,38). Several factors could have influenced the decrease in the prevalence of nonsusceptibility and resistance to penicillin observed in this study.…”

“…Several factors could have influenced the decrease in the prevalence of nonsusceptibility and resistance to penicillin observed in this study. First, after the introduction of PCV-7 in Spain (16,17,38) and other countries (6,22), significant reductions in the rates of penicillin resistance, erythromycin resistance, and multiresistance have been observed. The shift in the pneumococcal resistant population affects not only vaccinated children but also unvaccinated children and adults, as a result of a herd immunity effect (10,25,31), probably due to the fact that children are mainly responsible for the transmission of drug-resistant S. pneumoniae in the community (10,33).…”

“…Following the widespread use of the new conjugated heptavalent pneumococcal vaccine (PCV-7), a decrease in antibiotic resistance in pediatric pneumococcal isolates causing disease has been reported in several countries (5,38), not only in vaccinated individuals but also in unvaccinated individuals, as a result of the herd immunity effect (16). Nevertheless, some recent studies have observed an increase in the prevalence of drug-resistant S. pneumoniae as a result of an increase in the prevalence of the more resistant nonvaccine serotypes (27).…”

Serotype and antimicrobial profile distribution of invasive pneumococcal isolates in the pre-vaccine introduction era in Pretoria, South Africa, 2005 through 2009

“…This is similar to what has been reported from developed countries such as Spain, as well as from developing countries such as The Gambia and South Africa (Perez-Trallero et al, 2009;Cutts et al, 2005;Zar et al, 2008). The introduction of the PCV-7 vaccine will likely lead to a significant reduction of IPD especially in our region with its high burden of HIV.…”

Molecular characterization of Streptococcus pneumoniae invasive serotype 19A isolates from adults in two Spanish regions (1994–2009)

“…The incidence rates of invasive serotype 19A infections were calculated using the population attended by each hospital per year as the denominator. The identification of isolates and antimicrobial susceptibility methods were performed as previously reported [6,14]. Isolates were serotyped by the Quellung reaction and by polymerase chain reaction (PCR) [15].…”