Carriage of Streptococcus pneumoniae and Other Respiratory Bacterial Pathogens in Low and Lower-Middle Income Countries: A Systematic Review and Meta-Analysis

Abstract

BackgroundInfection with Streptococcus pneumoniae is a major cause of childhood morbidity and mortality worldwide, especially in low income countries where pneumococcal conjugate vaccines (PCVs) are still underused. In countries where PCVs have been introduced, much of their efficacy has resulted from their impact on nasopharyngeal carriage in vaccinated children. Understanding the epidemiology of carriage for S. pneumoniae and other common respiratory bacteria in developing countries is crucial for implementing appropriate vaccination strategies and evaluating their impact.Methods and FindingsWe have systematically reviewed published studies reporting nasopharyngeal or oropharyngeal carriage of S. pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, and Neisseria meningitidis in children and adults in low and lower-middle income countries. Studies reporting pneumococcal carriage for healthy children <5 years of age were selected for a meta-analysis. The prevalences of carriage for S. pneumoniae, H. influenzae, and M. catarrhalis were generally higher in low income than in lower-middle income countries and were higher in young children than in adults. The prevalence of S. aureus was high in neonates. Meta-analysis of data from young children before the introduction of PCVs showed a pooled prevalence estimate of 64.8% (95% confidence interval, 49.8%–76.1%) in low income countries and 47.8% (95% confidence interval, 44.7%–50.8%) in lower-middle income countries. The most frequent serotypes were 6A, 6B, 19A, 19F, and 23F.ConclusionsIn low and lower-middle income countries, pneumococcal carriage is frequent, especially in children, and the spectrum of serotypes is wide. However, because data are limited, additional studies are needed to adequately assess the impact of PCV introduction on carriage of respiratory bacteria in these countries.

Development of an Extended-Specificity Multiplex Immunoassay for Detection of Streptococcus pneumoniae Serotype-Specific Antigen in Urine by Use of Human Monoclonal Antibodies

“…The high sensitivity of this UAD assay allows for the possibility that it will also detect small amounts of polysaccharide antigen in urine as a result of carriage as well as disease. Pneumococcal carriage rates in children range from 30% to 86%, with higher rates in lower-income countries (65)(66)(67)(68)(69)(70)(71)(72), and studies have found positive BinaxNOW results in healthy children carrying pneumococci in their nasal pharynges (24)(25)(26)(27). Adult carriage rates are much lower than those of children; carriage in the United Kingdom is predicted to be approximately 3.4% (66).…”

Pneumococcal Carriage in Children under Five Years in Uganda-Will Present Pneumococcal Conjugate Vaccines Be Appropriate?

“…For the 2008 survey assumptions were 10% margin of error and an estimated prevalence of pneumococci that were resistant to antibiotics equal to 50% (to get the most conservative sample size), giving a sample size of 96 children colonised with pneumococci to estimate the true resistance prevalence. Given that an estimated 66% of the under-five population is colonized by pneumococci [9] a total sample of 152 children was needed, allowing for a drop-out rate of 5%. For the survey in 2009, the sample size calculations were set to estimate the true prevalence of children carrying pneumococci and the assumptions used were p equal to 50%, 5% margin of error, and a cluster effect of 1.7 was added, yielding a total number of 650 children to be swabbed for bacteria.…”

“…A range of 35–93% of healthy children aged under five years in low-income countries has been shown to be colonized with pneumococci in the nasopharynx [9,10]. Pneumococcal conjugate vaccine (PCV) reduces vaccine-type pneumococcal carriage and thereby the dynamics of serotype transmission and pneumococcal disease [11].…”

“…In the African studies included in a systematic review from 2014, between 36% and 56% of the carried pneumococcal serotypes in children less than 5 years old were of PCV7-types, between 37–56% for PCV10 and 50–64% for PCV13 [9]. However, serotype distribution in both IPD and carriage varies over time and updated knowledge on pneumococcal serotype distribution in carriage is needed in order to inform policy choices and to access baseline data prior to the introduction of PCV10 in Uganda.…”

Competitive Dominance within Biofilm Consortia Regulates the Relative Distribution of Pneumococcal Nasopharyngeal Density

“…Unlike strains belonging to serotype 1 or 5, which are highly prevalent in IPD cases but display low prevalence in carriage studies, serotype 6B, 19F, and 23F strains are also the most prevalent serotypes carried in the nasopharynx of children (6,32,33). While strains were able to form biofilms on both abiotic and biotic surfaces (i.e., human pharyngeal cells), only S6B and S23F dominated biofilm consortia when S19F colonized the same niche.…”