Prevalence and risk factors for nasopharyngeal carriage of Streptococcus pneumoniae among adolescents

Abstract

Data on the prevalence of pneumooccal nasopharyngeal carriage and its risk factors among adolescents are scarce. The aim of this study was to provide such information. A cross-sectional, population-based prospective study was conducted. Participants were 1013 adolescents (age range 10-19 years) randomly recruited in 22 public schools. Those schools were randomly chosen among 307 public schools from 11 Sanitary Districts of Salvador, Brazil. Nasopharyngeal samples were assessed by standard procedures to recover and identify Streptococcus pneumoniae. Data on potential risk factors were gathered by confidential interview based on a standardized questionnaire. Pneumococci were recovered from 8.2 % [83/1013, 95 % confidence interval (CI) 6.6-10.0]. By stepwise logistic regression, pneumococcal colonization was independently associated with younger age [odds ratio (OR) 0.85, 95 % CI 0.77-0.94, P50.001], being male (OR 1.78, 95 % CI 1.11-2.85, P50.02), exposure to passive smoke in the household (OR 1.76, 95 % CI 1.10-2.79, P50.02), having an upper respiratory infection during recruitment (OR 2.67, 95 % CI 1.67-4.28, P,0.001) and having a history involving an episode of acute asthma during the last year (OR 2.89, 95 % CI 1.18-7.08, P50.03). The estimated probability of pneumococcal colonization decreased with age (x 2 for trend58.52, P50.003). These findings provide tools for increasing the use of prevention strategies for pneumococcal diseases, such as pneumococcal vaccination among asthmatic patients and public health measures to stop smoking. INTRODUCTIONThe incidence of invasive pneumococcal disease is highest among children and the elderly (CDC, 1997). However, respiratory infections are an important cause of morbidity and mortality among adolescents (Benguigui, 1992). Among children, Streptococcus pneumoniae is a major causative agent of such infections (Heiskanen-Kosma et al., 1998). The nasopharynx is known to be the main ecological reservoir of S. pneumoniae, from where it can give rise to disease after extending to other areas of the respiratory tract or penetrating normally sterile body fluids (Austrian, 1986). Although nasopharyngeal isolates are not useful for predicting the causative agent of invasive disease in individuals, they reflect epidemiological aspects of pneumococcal disease in the community (Brueggemann et al., 2003).Studies conducted over the last decades have gradually revealed the connection between pneumococcal carriage, and mucosal and invasive infections caused by the (Inostroza et al., 1998). Thus, we estimated that 900 participants would be sufficient to detect a prevalence and the respective 95 % confidence interval (CI) of nasopharyngeal colonization ranging from 8-12 % (point prevalence510 %, 2 % error). We assumed a 12 % refusal to participate, so the sample size was established as 1000 participants. Demographic, clinical and epidemiological data were collected by a standardized questionnaire.Bacteriological data. Two trained biochemists collected nasopharyngeal specimens by rotat...

Nasopharyngeal bacterial colonization during the first wheezing episode is associated with longer duration of hospitalization and higher risk of relapse in young children

“…Moreover, among the cases with recurrent wheezing, children who had coexisted non-invasive bacterial colonization and virus infection presented more frequent cyanosis, longer duration of hospitalization, higher concentration of IL-10, and higher percentage of neutrophil compared with children with virus infection but without bacterial colonization. In a population-based study on adolescents, pneumococcal colonization was independently associated with a history of an exacerbation of asthma during the preceding year (25). The association to allergies was not reported.…”

“…Although there is variability in the peak age during childhood between studies, the nasopharyngeal colonization is much less during early adulthood compared to childhood (23,25). An increase in respiratory bacterial colonization has been associated with low socio-economic status, autumn-winter seasons, exposure to other children, prone sleeping position, upper respiratory or otitis media infection, immunosuppression or lack of immunization, use of pacifiers, hospitalization and xylitol consumption (21, 24, 2 6 ).…”

Current Trends in Streptococcus pneumoniae Infections and Their Treatment

“…Highest carriage rates (40-60 %) are observed in young children, especially those attending day care centers [6]. Carriage rates decrease with increasing age ranging from 12 % in older children to 6-10 % in adolescents and 3-4 % in adults [33]. Carriage rates in children can vary from 21 % in resource-rich settings to [90 % in LMIC [28].…”

Desenvolvimento e avaliação da resposta imune humoral de uma vacina anti-pneumocócica conjugada: polissacarídeo capsular sorotipo 14 - proteína de superfície pneumocócica A.

“…Portanto, pode-se inferir que a idade é um importante fator de risco para colonização pneumocócica e que a sua influência varia de acordo com a fase de crescimento ao longo da vida. De forma semelhante, a distribuição dos sorotipos pneumocócicos também pode variar de acordo com a região geográfica, o tempo e a apresentação clínica dos pacientes, onde a população negra, índios americanos e nativos do Alasca, indivíduos tabagistas, alcoolistas ou com condições médicas crônicas como diabetes, doença falciforme, doenças cardíacas, pulmonares e renais, doenças imunossupressoras, particularmente a AIDS, também fazem parte do grupo de risco (BEREZIN et al, 2007;CARDOZO et al, 2008;DAGAN;LIPSITCH, 2004;RUBINS et al, 1998).…”

“…No Brasil, a taxa de colonização pneumocócica em crianças de 8 a 71 meses varia de 21,2-55%, onde na população total foi relatada uma prevalência de colonização pneumocócica de 19-43% (CARDOZO et al, 2008).…”