Prevalence Of Pneumococcal Nasopharyngeal Carriage Research Articles

Pneumococcal infections and homelessness

SummaryObjectiveTo assess the prevalence of pneumococcal nasopharyngeal carriage, the role of potential risk factors, and the pneumococcal vaccination coverage among sheltered homeless people in Marseille, France.MethodsDuring the winters 2015-2018, we enrolled 571 sheltered homeless males and 54 non-homeless controls. Streptococcus pneumoniae was directly searched from nasal/pharyngeal samples using real-time polymerase chain reaction.ResultsThe homeless people were mostly migrants from African countries, with a mean age of 43 years. Pneumococcal vaccination coverage was low (3.1%). The overall pneumococcal carriage rate was 13.0% and was significantly higher in homeless people (15.3% in 2018) than in controls (3.7%), with p = 0.033. Among homeless people, being aged ≥ 65 years (1.97, 95% CI; 1.01-3.87), living in a specific shelter (OR = 1.80, 95% CI: 1.06-3.05), and having respiratory signs and symptoms at the time of enrolment (OR = 2.55, 95% CI: 1.54-4.21) were independently associated with pneumococcal carriage.ConclusionPneumococcal nasopharyngeal carriage, which is a precursor for pneumococcal disease in at-risk individuals, is frequent among French homeless people. Studies conducted in other countries have also reported outbreaks of pneumococcal infections in homeless people. Pneumococcal vaccination should be systematically considered for sheltered homeless people in France, as is being done in Canada since 2008.

Relationship Between Prevalence of Pneumococcal Serotypes and Their Neuraminidases in Carriers, Predictive Facts?

: Streptococcus pneumoniae is one of the leading causes of morbidity and mortality worldwide that mainly colonizes the upper respiratory tract in children and produces invasive infections such as meningitis, bacteremia, pneumonia, and otitis media. Pneumococcus species harbor a number of virulent genes that influence disease severity. Neuraminidase is a virulence factor that cleaves sialic acid. Pneumococcal nasopharyngeal carriage is common among healthy individuals and is considered an important transmission source. This topic, however, is less regarded in research from Iran. Therefore, the current study aimed at investigating the prevalence of pneumococcal nasopharyngeal carriage among Iranian children under six years of age. The study also aimed at determining the frequency of pneumococcal serotypes and the neuraminidase virulence genes (nanA, nanB, and nanC) among carriers. A total of 384 nasopharyngeal samples were collected from children under six years of age referred to healthcare centers of six provinces in Iran, including Tehran, Fars, Ardebil, Lorestan, Khorasan, and Sistan va Baluchistan from 2013 to 2016. Of these, 92 carriers were identified (24.0%; 95% confidence interval [CI]: 20.0, 28.5%). Identified pneumococcal serotypes included 6A/B (14.1%), 14, 3, and 19A (each 12.1%), 4, 19F, 23F (each 5.4%), 11 (4.3%), 18C, 22F, 9V, 19, 12, and 33F (each 2.1%), 5, 12F (each 1.1%) and non-typable (14.1%). Frequency of neuraminidase nanA, nanB, and nanC genes among 92 carriers was 100% (95% CI: 96.0, 100%), 85.9% (95% CI: 77.3, 91.6), and 62.0% (95% CI: 51.8, 71.2), respectively. The results showed that about 25% of children (n = 92) were pneumococcus carriers. A wide range of serotypes, some of which are known as virulent, were seen in the population. Prevalence of neuraminidase genes was also considerable.

Prevalence of Pneumococcal Nasopharyngeal Carriage Among Children 2-18 Months of Age: Baseline Study Pre Introduction of Pneumococcal Vaccination in Cuba.

A new vaccine candidate against pneumococcus is being developed in Cuba, and it is a priority of the national health system. There is limited information on nasopharyngeal colonization burden, though it is essential for monitoring the impact of the vaccine. The study aims to estimate the prevalence of nasopharyngeal colonization in children 2-18 months of age and identify circulating serotypes, antimicrobial resistance and its association with selected risk factors. A cross-sectional study was conducted between October and December 2013 in Cienfuegos municipality. Inclusion criteria were evaluated, and informed consent was obtained from the parents. Clinical and epidemiologic data were collected through a semistructured questionnaire. Nasopharyngeal swabs according to established protocols were taken. Data analysis included frequency distributions and comparison of proportions. The association between colonization and selected risk factors was assessed by multivariate analysis. A total of 984 children (87.2% living in urban areas) were included. The overall prevalence of colonization was 21.6%. The most frequent serotypes isolated were 6A (23.1%), 23F (10.8%), 6B (10.3%), 19F (8.5%) and 14 (3.3%). We found no resistance to β-lactamases in circulating serotypes. Living with sibling younger than 5 years, previous respiratory infections, previous hospitalization and day-care attendance were determinants of nasopharyngeal carriage. The findings suggest that the burden of pneumococcal disease and colonization in Cuba could be significantly affected after vaccine introduction.

ВНУТРИГОДОВАЯ ДИНАМИКА УРОВНЕЙ НОСИТЕЛЬСТВА ПНЕВМОКОККА И ЗАБОЛЕВАЕМОСТИ ВНЕБОЛЬНИЧНОЙ ПНЕВМОНИЕЙ В Г. ХАБАРОВСКЕ В 2015 ГОДУ

The research objective was to study prevalence of pneumococcal nasopharyngeal carriage among different age-group populations as well as evaluate annual dynamics of nasopharyngeal carriage levels against incidence rates of community-acquired pneumonia in Khabarovsk city in 2015. The bacteriological research was conducted among 2429 people (1100 adults and 1329 children) suffering from respiratory diseases. The level of pneumococcal carriage of the whole group was equal to 12.3±0.67%. The pneumococcal carriage was registered in all age-groups; its highest levels were diagnosed in children from 1 to 3 years old and in children from 3 to 6 years old (27.0±2.16 and 23.1±1.97%, respectively). The incidence rates of community-acquired pneumonia equaled to 290.2 per 100000 of general population and 687.1 per 100000 of children population. The comparative analysis of annual dynamics of pneumococcal carriage and community-acquired pneumonia incidence rates among general population of Khabarovsk city and separately for children from 0 to 14 years old has shown a correlation between these epidemiologic manifestations. Typically, pneumococcal carriage and incidence rates are the lowest in August; they elevate in September due to influence of common factors that are associated with “mixing” of people. The peculiarity of annual dynamic of community-acquired pneumonia incidence rates is a double-wave course with maximum in April and September. The revealed trends show the correlation between epidemic process of community-acquired pneumonia and undetected epidemic process of pneumococcal infections manifested as pneumococcal carriage.

Effect on nasopharyngeal pneumococcal carriage of replacing PCV7 with PCV13 in the Expanded Programme of Immunization in The Gambia

IntroductionIn 2011, two years after the introduction of 7-valent Pneumococcal conjugate vaccine (PCV7), the Gambian immunization programme replaced PVC7 with PCV13 (13-valent). Our objective was to assess the additional impact of PCV13 on prevalence of pneumococcal nasopharyngeal carriage. MethodsWe recruited healthy Gambian infants who had received three PCV doses. Nasopharyngeal swabs were collected from infants and their mothers during two cross-sectional surveys (CSS) conducted in infants vaccinated with PCV7 (CSS1) and vaccinated with PCV13 (CSS2). Pneumococci were isolated and serotyped following standardized methods. Whole genome sequencing was performed on non-typable pneumococcus isolated in CSS1 and CSS2. Results339 and 350 infants and their mothers were recruited in CSS1 and CSS2, respectively. Overall prevalence of pneumococcal carriage was 85.4% in infants. Among infants, prevalence of vaccine type (VT) carriage was lower in CSS2 [9.4% versus 4.9% (p=0.025) for PCV7-VT; 33.3% versus 18.3% (p<0.001) for PCV13-VT and 23.9% versus 13.7% (p=0.001) for the 6 additional serotypes included in PCV13]. At CSS2, there was a decrease of serotypes 6A (from 15.3% to 5.7%, p<0.001) and 19F (from 5.6% to 1.7%, p=0.007), and an increase of non-typable pneumococci (0.3–6.0%, p<0.001), most of which (82.4%) were from typable serotype backgrounds that had lost the ability to express a capsule. Prevalence of overall and VT carriage in mothers was similar in CSS1 and CSS2. ConclusionsReplacing PCV7 for PCV13 rapidly decreased prevalence of VT carriage among vaccinated Gambian infants. An indirect effect in mothers was not observed yet. Vaccine-driven selection pressure may have been responsible for the increase of non-typable isolates.

Seasonality of Pneumococcal Nasopharyngeal Carriage in Rural Gambia Determined within the Context of a Cluster Randomized Pneumococcal Vaccine Trial.

BackgroundWe conducted an ancillary study among individuals who had participated in a PCV-7 trial in rural Gambia, to determine the influence of season on the prevalence of pneumococcal carriage.Methods636 individuals above 30 months of age were followed from 4 to 20 months after vaccination with PCV-7 or meningococcal-conjugate-vaccine. Nasopharyngeal swabs were collected periodically between November 2006 and June 2008. Overall, 4,495 NPS were collected.ResultsPrevalence of pneumococcal nasopharyngeal carriage in the study subjects (median age 11 years) was 55.0%; this prevalence decreased linearly with increasing age (p = 0.001). Prevalence of carriage was significantly higher during the dry than the rainy season for any pneumococcal carriage [57.6% versus 47.8% (p<0.001)], pneumococcal vaccine serotype carriage [10.3% versus 6.5% (p< 0.001)] and non-vaccine serotype carriage [49.7% versus 42.7% (p<0.001)]. Differences remained significant in the adjusted analysis.ConclusionsIn areas of Africa with marked variation in rainfall, seasonality of pneumococcal carriage needs to be considered when interpreting carriage data.

Changes in Streptococcus pneumoniae serotype distribution in invasive disease and nasopharyngeal carriage after the heptavalent pneumococcal conjugate vaccine introduction in Bogotá, Colombia

BackgroundIn Bogotá, the Heptavalent Conjugate Vaccine (PCV7) was introduced into childhood immunization schedule since 2009. The aim of this study was to assess the changes in serotype distribution and penicillin susceptibility of Streptococcus pneumoniae isolates recovered from nasopharyngeal samples and invasive disease among children living in Bogotá, before and after PCV7 introduction. MethodsNasopharyngeal swabs were collected from healthy children aged between 12 and 18 months of age before (years 2005–2006) and after (2011) PCV7 introduction. Identification of S. pneumoniae was performed by multiplex PCR. Serotype was determined by PCR and Quellung reaction. Susceptibility to penicillin, ceftriaxone, trimethoprim-sulfamethoxazole, chloramphenicol, tetracycline and erythromycin was evaluated. In addition, distribution of serotypes and antimicrobial susceptibility before and after vaccine introduction among invasive isolates recovered from children ≤2 years old living in Bogotá was analyzed. ResultsPrevalence of pneumococcal nasopharyngeal carriage declined from 55.7% (137/246) in unvaccinated to 44.2% (87/197) (p=0.01) in vaccinated children. The proportion of children carrying PCV7 serotypes decreased from 23.6% (58/246) to 7.6% (15/197) (p<0.001). The decrease was counterbalanced by an increase in the proportion of non-PCV7 serotypes. The most prevalent among emerging serotypes were 15A, 15B, 15C, 11A and 35B. Among IPD isolates, PCV7 serotypes decreased from 69.1% (235/340) in 2005/2009 to 38.0% (32/84) in 2010/2011 (p<0.001). The increase of non-PCV7 serotypes was significant. Resistance to penicillin among invasive isolates recovered from meningitis decreased from 41.1% (30/73) in the pre-vaccine period to 14.2% (2/14) in post-vaccine period (p=0.02). ConclusionsA decrease in the prevalence of pneumococcal nasopharyngeal carriage following the introduction of PCV7 vaccine, have been overshadowed by an important surge in the prevalence of non-PCV7 serotypes. Systematic surveillance combining nasopharyngeal carriage surveys and IPD detection could help in evaluating the impact of conjugate vaccines.

Prevalence of nasopharyngeal carriage of pneumococcus in preschool children attending day care in London

Objective:To estimate the prevalence of nasopharyngeal (NP) carriage of pneumococcus (Streptococcus pneumoniae) and describe the antibiotic resistance patterns and serotypes in young children attending group day care in London.Design and...

Étude du portage rhinopharyngé de Streptococcus pneumoniae chez les enfants sains âgés de 2 à 24 mois en Nouvelle-Calédonie

The aims of this study were to determine the prevalence of pneumococcal nasopharyngeal carriage in New-Caledonian children less than two years of age, to define risk factors for carriage, and to document the serotypes present in New Caledonia prior to the implementation of the conjugate pneumococcal vaccine. From August 2002 to April 2003, nasopharyngeal samples were collected on 1040 children less than two years of age during scheduled visits to dispensaries for routine immunization. Of the 1040 samples, 544 (52%) were positive for Streptococcus pneumoniae. The percentage of pneumococcal strains with reduced susceptibility to penicillin (PRSP) was 21%. Several risk factors for pneumococcal carriage were identified. These included the Province that the child lived in, the ethnic group, age, and having a sibling less than 6 years of age. Risk factors for carriage of PRSP carriage were similar but also included additional risk factors such as attendance at day care and a history of antibiotic treatment. The eight most frequent serotypes were 6B, 19F, 14, 23F, 6A, 19A, 11A, and 16F. These serotypes accounted for 60% of all strains detected. The most frequent serotypes of PRSP were 14, 9 V, 19F, 23F, and 6B. They were more often identified in european children and 80% were vaccine serotypes. However, overall 250/544 (46%) of all pneumococcal isolates were those included in the 7 serotype vaccine.