Non-Invasive Pneumococcal Pneumonia in Portugal—Serotype Distribution and Antimicrobial Resistance

Abstract

There is limited information on the serotypes causing non-invasive pneumococcal pneumonia (NIPP). Our aim was to characterize pneumococci causing NIPP in adults to determine recent changes in serotype prevalence, the potential coverage of pneumococcal vaccines and changes in antimicrobial resistance. Serotypes and antimicrobial susceptibility profiles of a sample of 1300 isolates recovered from adult patients (≥18 yrs) between 1999 and 2011 (13 years) were determined. Serotype 3 was the most frequent cause of NIPP accounting for 18% of the isolates. The other most common serotypes were 11A (7%), 19F (7%), 19A (5%), 14 (4%), 22F (4%), 23F (4%) and 9N (4%). Between 1999 and 2011, there were significant changes in the proportion of isolates expressing vaccine serotypes, with a steady decline of the serotypes included in the 7-valent conjugate vaccine from 31% (1999–2003) to 11% (2011) (P<0.001). Taking together the most recent study years (2009–2011), the potential coverage of the 13-valent conjugate vaccine was 44% and of the 23-valent polysaccharide vaccine was 66%. While erythromycin resistance increased from 8% in 1999–2003 to 18% in 2011 (P<0.001), no significant trend was identified for penicillin non-susceptibility, which had an average value of 18.5%. The serotype distribution found in this study for NIPP was very different from the one previously described for IPD, with only two serotypes in common to the ones responsible for half of each presentation in 2009–2011 – serotypes 3 and 19A. In spite of these differences, the overall prevalence of resistant isolates was similar in NIPP and in IPD.

Burden of pneumococcal community-acquired pneumonia in adults across Europe: A literature review

“…These publications are summarised in online Supplementary Table S1. Of the included publications, 31 were prospective or surveillance [5,21,25,28,30,33,38,40,41,46,49 National population-based epidemiologic surveillance data for pneumonia were available from Norway [54], Portugal [58] and Spain [59,75,77]. As observed by Tichopad and colleagues [29], epidemiologic data in Central and Eastern Europe were predominantly collected from hospital settings, and there was a lack of data on outpatient CAP, with the authors instead using inpatient-to-outpatient ratios from a retrospective chart review to estimate outpatient incidence in the Czech Republic, Hungary, Poland and Slovakia.…”

Serotype Replacement in Adult Pneumococcal Pneumonia after the Introduction of Seven-Valent Pneumococcal Conjugate Vaccines for Children in Japan: a Systematic Literature Review and Pooled Data Analysis

“…Therefore, it is a reasonable assumption that the serotype distribution of adult pneumococcal pneumonia in Japan will change during the post-PCV13 period (9,10). Sustaining a nationwide surveillance system and periodic reporting is therefore crucial for investigating the effect of routine PCV13 vaccinations for children on pneumococcal serotype distribution in Japan.…”

“…Numerous studies have reported that the serotype distribution among adult invasive pneumococcal disease (IPD) cases is influenced by the introduction of PCV vaccination in children (5-7), which is called "serotype replacement." However, few studies have shown serotype replacement in cases of adult pneumococcal pneumonia, all of which were from Europe (8)(9)(10). Because serotype distribution differs between pneumonia cases and IPD cases (8,10), it is crucial to clarify the impact of PCV introduction in children on the serotype distribution in adult pneumonia, which has a far greater disease burden than does IPD.…”

“…However, few studies have shown serotype replacement in cases of adult pneumococcal pneumonia, all of which were from Europe (8)(9)(10). Because serotype distribution differs between pneumonia cases and IPD cases (8,10), it is crucial to clarify the impact of PCV introduction in children on the serotype distribution in adult pneumonia, which has a far greater disease burden than does IPD. Furthermore, there is a geographic difference in the serotype distribution of adult pneumococcal pneumonia, even among European counties including the United Kingdom, Spain, and Portugal (8)(9)(10).…”

“…Because serotype distribution differs between pneumonia cases and IPD cases (8,10), it is crucial to clarify the impact of PCV introduction in children on the serotype distribution in adult pneumonia, which has a far greater disease burden than does IPD. Furthermore, there is a geographic difference in the serotype distribution of adult pneumococcal pneumonia, even among European counties including the United Kingdom, Spain, and Portugal (8)(9)(10). Serotype replacement in adult pneumococcal pneumonia has not been well studied in Asia, including in Japan.…”