Pneumococcal carriage, density, and co-colonization dynamics: a longitudinal study in Indonesian infants (original) (raw)
Related papers
Bangladesh Journal of Infectious Diseases, 2020
Background: Detection and monitoring of nasopharyngeal carriage of Streptococcus pneumoniae is important to assess the impact and effectiveness of pneumococcal vaccine programs. Objective: The aims of this study were to assess the nasopharyngeal colonization rate, investigate some of the risk factors for nasopharyngeal colonization with S. pneumoniae from healthy children. Methodology: The study was conducted in the department of microbiology of Dhaka Medical College Hospital (DMCH). Data were collected among 200 under five healthy children in different age group (13 months to 36 months), from different socioeconomic status with cramped housing condition from Pediatric OPD of Dhaka Medical College Hospital. S. pneumoniae were isolated and identified by culture, Gram staining, biochemical test and polymerase chain reaction (PCR). Result: Out of 200 nasopharyngeal swabs, 67 (33.50%) were found to be carriers positive by culture and 92(46%) by PCR. The carrier rate was higher among 13 months to 36 months, low and middle socioeconomic groups and among with cramped housing condition. Conclusion: In conclusion various factors may affect the nasopharyngeal colonization with S. pneumoniae including early age of life, different socioeconomic and living condition.
Pan African Medical Journal, 2019
Introduction: streptococcus pneumonia is a leading cause of bacterial pneumonia, meningitis and sepsis in children, and pneumococcal carriage is an important source of horizontal spread of these pathogens within the community. Methods: a questionnaire was addressed to parents for the collection of sociodemographic and medical information. Nasopharyngeal swabbing was processed using a molecular method. We used logistic regression models to examine independent associations between pneumococcal carriage and potential risk factors. All associations with a p-value of < 0.25 in the bivariate regression analyses were subsequently entered in the multivariate regression model. Results: a total of 637 children aged 1 to 59 months admitted for acute respiratory infection were included. The rate of respiratory virus carriage was 76%, whereas that of bacteria was 47% and that of bacteria-virus co-colonization was 42%. A bivariate analysis showed that carriage was not related to gender, father's or mother's education level, father's occupation, type of housing or lighting, or passive exposure to cigarette smoking in the house. It was also not linked to complete vaccination with PCV-13 or PPSV-23 and antibiotic treatment prior to hospitalization. A multivariate analysis showed that carriage was related to age greater than 3 months, maternal occupation, house flooring type, and co-colonization of another bacterium and virus. Conclusion: these results can be helpful to understand the dynamics of pneumococcal nasopharyngeal colonization; they confirm the interest of vaccinating infants before the age of 3 months with appropriate vaccine to prevent spread nasopharyngeal colonization and pneumococcal diseases in children.
Nasopharyngeal carriage of resistant pneumococci in young South Indian infants
Epidemiology and Infection, 2002
Streptococcus pneumoniae is the leading bacterial cause of life-threatening infections in infants. Although antibiotic resistance affects management of pneumococcal infections, few data on patterns of resistance are available for India. We examined nasopharyngeal carriage of antibiotic-resistant pneumococci in 464 South Indian infants between 2 and 6 months. Newly acquired serotypes were screened for susceptibility to cotrimoxazole, erythromycin and penicillin using disk diffusion. Cumulative prevalence of pneumococcal carriage rose from 53·9% at 2 months to 70·2% at 6 months. The prevalence of strains that were not susceptible to penicillin, co-trimoxazole and erythromycin was 3·4, 81·1 and 37·2%, respectively. Carriage of erythromycin non-susceptible strains declined significantly between ages 4 months and 6 months (44·1 vs. 10·7%). More than 87% of the isolates screened were non-susceptible to [ges ]1 antibiotic. Serogroups/types that were most frequently non-susceptible to 1 or ...
Longitudinal Study on Pneumococcal Carriage During the First Year of Life in Bangladesh
Pediatric Infectious Disease Journal, 2007
Background: The strong herd immunity effect and the serotype replacement associated with the use of the pneumococcal conjugate vaccine have highlighted the importance of asymptomatic pneumococcal carriage. To describe the development of pneumoccoccal carriage in a developing country setting we carried out a longitudinal pneumococcal carriage study in Bangladesh. Methods: Ninety-nine children, born in Savar, Bangladesh between May 2000 and April 2001, were enrolled in the study with their families. Nasopharyngeal samples were collected at prescheduled 2-4 week intervals from the index children and from their family members. The nasopharyngeal swabs were cultured for pneumococcal growth and pneumococci were identified and serotyped by standard methods. Results: We collected 1459 samples (92% of those planned) from the 99 index children and 2865 samples from other family members. The data showed high point prevalences of pneumococcal carriage among newborns (40-50% from 8 weeks of age on), a rapid pneumococcal acquisition with age (50% of the children had been colonized by pneumococci at least once by the age of 8 weeks) and a wide range of different serogroups/types (SGT). SGT 6 and 19 accounted for 35% of the pneumococci isolated from children Ͻ1-year-old, followed by SGT 15, 23, and 10 for a total of 56%. The SGT distribution in children up to 9-year-old was similar to that among the Ͻ1 year olds, with SGT 6 and 19 predominating. Older children and adults differed from the younger children by not having clearly predominating SGTs. Conclusions: The features found in our study are typical of pneumococcal carriage in developing countries. We believe that results from longitudinal modeling of carriage based on these extensive data can have wide geographic application.
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2017
Previous studies suggested an association between upper airway pneumococcal colonization density and pneumococcal pneumonia, but data in children are limited. Using data from the Pneumonia Etiology Research for Child Health (PERCH) study, we assessed this potential association. PERCH is a case-control study in 7 countries: Bangladesh, The Gambia, Kenya, Mali, South Africa, Thailand, and Zambia. Cases were children aged 1-59 months hospitalized with World Health Organization-defined severe or very severe pneumonia. Controls were randomly selected from the community. Microbiologically confirmed pneumococcal pneumonia (MCPP) was confirmed by detection of pneumococcus in a relevant normally sterile body fluid. Colonization density was calculated with quantitative polymerase chain reaction analysis of nasopharyngeal/oropharyngeal specimens. Median colonization density among 56 cases with MCPP (MCPP cases; 17.28 × 106 copies/mL) exceeded that of cases without MCPP (non-MCPP cases; 0.75 × ...
PLoS ONE, 2014
Background: Among pneumococcal serotypes, some serotypes are more prevalent in the nasopharynx than others; determining factors for higher prevalence remain to be fully explored. As non-vaccine serotypes have emerged after the introduction of 7-valent conjugate vaccines, study of serotype specific epidemiology is in need. When two or more serotypes co-colonize, they evolve rapidly to defend host's immune responses; however, a clear association of cocolonization with a clinical outcome is lacking. Methods: Children less than 5 years old who were admitted to hospital due to acute respiratory infections (ARI) (n = 595) and healthy children (n = 350) were recruited. Carriage of pneumococcus was determined by culture and lytA PCR in the nasopharyngeal samples. Serotype/serogroup detection and its quantification were done by the nanofluidic real time PCR system. Spearman's correlation and logistic regression were used to examine a correlation of serotype/serogroup specific bacterial load with its prevalence and an association of co-colonization with ARI respectively. Results: Serotype/serogroup specific bacterial load was correlated with its prevalence, both in ARI cases (Spearman's rho = 0.44, n = 186; P,0.0001) and healthy children (Spearman's rho = 0.41, n = 115; P,0.0001). The prevalence of multiple serotypes was more common in ARI cases than in healthy children (18.5% vs 7.1%; aOR 2.92, 95% CI: 1.27-6.71; P = 0.01). The dominant serotype in the co-colonization had a 2 log10 higher bacterial load than the subdominant serotype, both in ARI cases (P,0.001) and healthy children (P,0.05). Conclusions: High bacterial load in the nasopharynx may help transmit pneumococci among hosts, and increase the chance of successful acquisition and colonization. Co-colonization of multiple serotypes of pneumococci is linked with ARI, which infers the interactions of multiple serotypes may increase their pathogenicity; however, they may compete for growth in number.
Frontiers in Pediatrics
Streptococcus pneumoniae (the pneumococcus) carriage precedes invasive disease and influences population-wide strain dynamics, but limited data exist on temporal carriage patterns of serotypes due to the prohibitive costs of longitudinal studies. Here, we report carriage prevalence, clearance and acquisition rates of pneumococcal serotypes sampled from newborn infants bi-weekly from weeks 1 to 27, and then bi-monthly from weeks 35 to 52 in the Gambia. We used sweep latex agglutination and whole genome sequencing to serotype the isolates. We show rapid pneumococcal acquisition with nearly 31% of the infants colonized by the end of first week after birth and quickly exceeding 95% after 2 months. Co-colonization with multiple serotypes was consistently observed in over 40% of the infants at each sampling point during the first year of life. Overall, the mean acquisition time and carriage duration regardless of serotype was 38 and 24 days, respectively, but varied considerably between s...
Journal of Infectious Diseases, 2012
Background. To understand and model the impact of pneumococcal conjugate vaccines at the population level, we need to know the transmission dynamics of individual pneumococcal serotypes. We estimated serotypespecific clearance and acquisition rates of nasopharyngeal colonization among Kenyan children. Methods. Children aged 3-59 months who were identified as carriers in a cross-sectional survey were followed-up approximately 1, 2, 4, 8, 16, and 32 days later and monthly thereafter until culture of 2 consecutive swabs yielded an alternative serotype or no pneumococcus. Serotype-specific clearance rates were estimated by exponential regression of interval-censored carriage durations. Duration was estimated as the reciprocal of the clearance rate, and acquisition rates were estimated on the basis of prevalence and duration, assuming an equilibrium state. Results. Of 2840 children sampled between October 2006 and December 2008, 1868 were carriers. The clearance rate was 0.032 episodes/day (95% confidence interval [CI], .030-.034), for a carriage duration of 31.3 days, and the rate varied by serotype (P < .0005). Carriage durations for the 28 serotypes with ≥10 carriers ranged from 6.7 to 50 days. Clearance rates increased with year of age, adjusted for serotype (hazard ratio, 1.21; 95% CI, 1.15-1.27). The acquisition rate was 0.061 episodes/day (95% CI, .055-.067), which did not vary with age. Serotypespecific acquisition rates varied from 0.0002 to 0.0022 episodes/day. Serotype-specific acquisition rates correlated with prevalence (r = 0.91; P < .00005) and with acquisition rates measured in a separate study involving 1404 newborns in Kilifi (r = 0.87; P < .00005). Conclusions. The large sample size and short swabbing intervals provide a precise description of the prevalence, duration, and acquisition of carriage of 28 pneumococcal serotypes. In Kilifi, young children experience approximately 8 episodes of carriage per year. The declining prevalence with age is attributable to increasing clearance rates.
BMC Infectious Diseases, 2010
Background: Streptococcus pneumoniae is an important cause of community acquired pneumonia, sepsis, meningitis and otitis media globally and has been incriminated as a major cause of serious childhood bacterial infections in The Gambia. Better understanding of the dynamics of transmission and carriage will inform control strategies. Methods: This study was conducted among 196 mother-infant pairs recruited at birth from six villages in the West Kiang region of The Gambia. Nasopharyngeal swabs were collected from mother-infant pairs at birth (within 12 hours of delivery), 2, 5 and 12 months. Standard techniques of culture were used to identify carriage and serotype S. pneumoniae. Results: Of 46 serotypes identified, the 6 most common, 6A, 6B, 14, 15, 19F and 23F, accounted for 67.3% of the isolates from infants. Carriage of any serotype among infants rose from 1.5% at birth to plateau at approximately 80% by 2 m (prevalence at 2 m = 77%; 5 m = 86%; 12 m = 78%). Likewise, maternal carriage almost doubled in the first 2 months post-partum and remained elevated for the next 10 m (prevalence at birth = 13%; 2 m = 24%; 5 m = 22%; 12 m = 21%). Carriage was significantly seasonal in both infants and mothers with a peak in December and lowest transmission in August. The total number of different serotypes we isolated from each infant varied and less than would be expected had the serotypes assorted independently. In contrast, this variability was much as expected among mothers. The halflife of a serotype colony was estimated to be 1.90 m (CI 95% : 1.66-2.21) in infants and 0.75 m (CI 95% : 0.55-1.19) in mothers. While the odds for a serotype to be isolated from an infant increased by 9-fold if it had also been isolated from the mother, the population attributable fraction (PAF) of pneumococcal carriage in infants due to maternal carriage was only 9.5%. Some marked differences in dynamics were observed between vaccine and non-vaccine serotypes. Conclusions: Colonisation of the nasopharynx in Gambian infants by S. pneumoniae is rapid and highly dynamic. Immunity or inter-serotype competition may play a role in the dynamics. Reducing mother-infant transmission would have a minimal effect on infant carriage.