Carriage Of Streptococcus Research Articles

The Carrier Status of Streptococcus pneumoniae in a Multi-National Medical Student Population.

Nasopharyngeal carriage of Streptococcus pneumoniae (S. pneumoniae) is a well-established risk factor for invasive disease. An unnecessarily high incidence of morbidity attributed to S. pneumoniae is vaccine-preventable. The objectives of this study were to determine the prevalence of S. pneumoniae carriage and to analyze the different vaccination schemes in a multinational population of final-year medical students. An observational cross-sectional study including final-year medical students attending their Infectious Diseases rotation. One nasal and pharyngeal swab were collected from each participant who underwent a minimum eight-hour period of fasting and without rinsing or brushing teeth. Written informed consent was obtained from all participants. A univariate statistical analysis was carried out with statistical significance set at p <0.05. Fifty students agreed to participate in this study (age range: 23-35, average: 24.86 ± 2.12 years). Six (12%) students had the pneumococcal vaccine: four (16%) from the foreign group and two (8%) from the Romanian group (OR: 2.19, 95% CI: 0.36-13.21, p=0.39). The carrier status for S. pneumoniae was 0%. A total of 12 (24%) specimens yielded microbial presence: S. aureus (n=8), S. pyogenes (n=1), Group C Streptococcus (n=1), Group G Streptococcus (n=1) and K. pneumoniae (n=1). All 13 (26%) specimens of alpha-hemolysis were identified from foreign students (OR: 55.08, 95% CI: 3.02-1003.75, p=0.0068), but had no clinical relevance, S. pneumoniae being ruled out. The carrier status among vaccinated participants was 0%. The rate of microorganism isolation was twice that in Romanian students compared to foreign students.

Inappropriate treatment of community-acquired pneumonia among children under five years of age in Tanzania

ObjectiveTo describe the treatment of community-acquired pneumonia (CAP) in children under five years in Tanzania. MethodsBetween January and December 2017, children aged 2–59 months with chest radiography-confirmed CAP were enrolled. The parents were interviewed to collect information on the patients and home-based medication. Clinical information was derived from the patient files. Nasopharyngeal swab and blood samples were collected for isolation of the causative pathogens. Swab samples were analysed by quantitative PCR whereas blood samples were tested using BacT/Alert 3D. ResultsOverall, 109 children with CAP were included in this analysis. Provision of care to most children was delayed (median = 4.6 days). A quarter (26.6%) were given unprescribed/leftover antibiotics at home. Only one child had positive bacterial culture. Referrals were associated with nasopharyngeal carriage of Streptococcus pneumoniae (p = 0.003) and Haemophilus influenzae (p = 0.004). Of all admitted children, more than a quarter (n = 29) did not need to be hospitalised and inappropriately received injectable instead of oral antibiotics. ConclusionWe found high rates of home treatment, particularly with antibiotics. Appropriate health care was delayed for most children because of home treatment. Efforts are needed at the community level to improve awareness of antimicrobial resistance.

Exposure to diesel exhaust particles increases susceptibility to invasive pneumococcal disease

BackgroundThe World Health Organization estimates that air pollution is responsible for 7 million deaths per annum, with 7% of these attributable to pneumonia. Many of these fatalities have been linked to exposure to high levels of airborne particulates, such as diesel exhaust particles (DEPs).ObjectivesWe sought to determine whether exposure to DEPs could promote the progression of asymptomatic nasopharyngeal carriage of Streptococcus pneumoniae to invasive pneumococcal disease.MethodsWe used mouse models and in vitro assays to provide a mechanistic understanding of the link between DEP exposure and pneumococcal disease risk, and we confirmed our findings by using induced sputum macrophages isolated from healthy human volunteers.ResultsWe demonstrate that inhaled exposure to DEPs disrupts asymptomatic nasopharyngeal carriage of S pneumoniae in mice, leading to dissemination to lungs and blood. Pneumococci are transported from the nasopharynx to the lungs following exposure to DEPs, leading to increased proinflammatory cytokine production, reduced phagocytic function of alveolar macrophages, and consequently, increased pneumococcal loads within the lungs and translocation into blood. These findings were confirmed by using DEP-exposed induced sputum macrophages isolated from healthy volunteers, demonstrating that impaired innate immune mechanisms following DEP exposure are also at play in humans.ConclusionLung inhaled DEPs increase susceptibility to pneumococcal disease by leading to loss of immunological control of pneumococcal colonisation, increased inflammation, tissue damage, and systemic bacterial dissemination.

Nasopharyngeal carriage of Streptococcus pneumoniae in children from day-care centers in Smolensk

Objective. To investigate a nasopharyngeal carriage and serotypes of S. pneumoniae in children aged 3 to 6 years from day-care centers in Smolensk. Materials and Methods. A total of 245 isolates of S. pneumoniae from 1027 nasopharyngeal swabs from healthy children attending day-care centers was tested. Identification of S. pneumoniae was performed according morphological, cultural and antigenic characteristics (Slidex pneumo-Kit, bioMeriеux, France), susceptibility to optohin and bile. Extraction of S. pneumoniae DNA (338) from nasopharyngeal specimens and cultures was performed using nucleic acids extraction kit AmpliSens® DNA-sorb-В (Interlabservice, Russia). Molecular typing was performed using CDC-recommended PCR method with 22 pairs of primers. Results. Children without signs of infection diseases from 14 day-care centers were examined, whose parents have signed an informed consent. There were 245 (24.0%) isolates of S. pneumoniae from 1027 specimens of nasopharynx’s swabs. The partly vaccinated with PCV13 were children aged 3–4 years – 311 (30.3%), in 95 children were healthy carriage (38.2%) of S. pneumoniae. The majority of children under 4 years (716⁄69.7%) were non vaccinated, healthy carriage of S. pneumoniae were 216 (29.3%). The predominant serotypes of S. pneumoniae in partly vaccinated children were: 3 (9.8%), 6AB (17.9%), 19F (13.8%), 11AD (12.2%), 23F (5.3%), 19A (2%), 18ABCF (1.6%), 14 (2%), 9AV (1.2%), 6CD (0.8%). The coincidence of S. pneumoniae serotypes in vaccinated children and included in PCV13 were 54%. The most common serotypes of S. pneumoniae in non-vaccinated children were: 11AD (12.2%), 15A/F (2%), 23A (2%), 22AF (0.4%), 19A (1.3%), 33FA/37 (1.6%) and non-typeable serotypes (27.8%). Conclusions. The low coverage of pneumococcal vaccine in children under 6 years shows the initial process of its implementation in Health Care. We detect the reduction of vaccine serotypes in children with incomplete immunization (54%) and notable increase in non-typeable serotypes (27.8%) in nonvaccinated children.

Determinants of high residual post-PCV13 pneumococcal vaccine-type carriage in Blantyre, Malawi: a modelling study

BackgroundIn November 2011, Malawi introduced the 13-valent pneumococcal conjugate vaccine (PCV13) into the routine infant schedule. Four to 7 years after introduction (2015–2018), rolling prospective nasopharyngeal carriage surveys were performed in the city of Blantyre. Carriage of Streptococcus pneumoniae vaccine serotypes (VT) remained higher than reported in high-income countries, and impact was asymmetric across age groups.MethodsA dynamic transmission model was fit to survey data using a Bayesian Markov-chain Monte Carlo approach, to obtain insights into the determinants of post-PCV13 age-specific VT carriage.ResultsAccumulation of naturally acquired immunity with age and age-specific transmission potential were both key to reproducing the observed data. VT carriage reduction peaked sequentially over time, earlier in younger and later in older age groups. Estimated vaccine efficacy (protection against carriage) was 66.87% (95% CI 50.49–82.26%), similar to previous estimates. Ten-year projected vaccine impact (VT carriage reduction) among 0–9 years old was lower than observed in other settings, at 76.23% (CI 95% 68.02–81.96%), with sensitivity analyses demonstrating this to be mainly driven by a high local force of infection.ConclusionsThere are both vaccine-related and host-related determinants of post-PCV13 pneumococcal VT transmission in Blantyre with vaccine impact determined by an age-specific, local force of infection. These findings are likely to be generalisable to other Sub-Saharan African countries in which PCV impact on carriage (and therefore herd protection) has been lower than desired, and have implications for the interpretation of post-PCV carriage studies and future vaccination programs.

Factors associated with pneumococcal carriage and density in infants and young children in Laos PDR.

Nasopharyngeal carriage of Streptococcus pneumoniae (the pneumococcus) is a precursor to pneumococcal disease. Several host and environmental factors have been associated with pneumococcal carriage, however few studies have examined the relationship between host factors and pneumococcal carriage density. We sought to identify risk factors for pneumococcal carriage and density using data from cross-sectional pneumococcal carriage surveys conducted in the Lao People's Democratic Republic before and after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13). Nasopharyngeal swabs were collected infants from aged 5-8 weeks old (n = 999) and children aged 12-23 months (n = 1,010), pneumococci detected by quantitative PCR, and a risk factor questionnaire completed. Logistic and linear regression models were used to evaluate associations between participant characteristics and pneumococcal carriage and density. In infants aged 5-8 weeks, living in a household with two or more children under the age of five years (aOR 1.97; 95% CI 1.39-2.79) and low family income (aOR 1.64; 95% CI 0.99-2.72) were positively associated with pneumococcal carriage. For children aged 12-23 months, upper respiratory tract infection (URTI) symptoms (aOR 2.64; 95% CI 1.97-3.53), two or more children under five in the household (aOR 2.40; 95% CI 1.80-3.20), and rural residence (aOR 1.84, 95% CI 1.35-2.50) were positively associated with pneumococcal carriage. PCV13 vaccination was negatively associated with carriage of PCV13 serotypes (aOR 0.60; 95% CI 0.44-0.83). URTI symptoms (p < 0.001), current breastfeeding (p = 0.005), rural residence (p = 0.012), and delivery by Caesarean section (p = 0.035) were associated with higher mean pneumococcal density in pneumococcal carriers (both age groups combined). This study provides new data on pneumococcal carriage and density in a high disease burden setting in southeast Asia.

Generation of protective pneumococcal-specific nasal resident memory CD4+ T cells via parenteral immunization.

The generation of tissue-resident memory T cells (TRM) is an essential aspect of immunity at mucosal surfaces, and it has been suggested that preferential generation of TRM is one of the principal advantages of mucosally administered vaccines. We have previously shown that antigen-specific, IL-17-producing CD4+ T cells can provide capsular antibody-independent protection against nasal carriage of Streptococcus pneumoniae; but whether pneumococcus-responsive TRM are localized within the nasal mucosa and are sufficient for protection from carriage has not been determined. Here, we show that intranasal administration of live or killed pneumococci to mice generates pneumococcus-responsive IL-17A-producing CD4+ mucosal TRM. Furthermore, we show that these cells are sufficient to mediate long-lived, neutrophil-dependent protection against subsequent pneumococcal nasal challenge. Unexpectedly, and in contrast with the prevailing paradigm, we found that parenteral administration of killed pneumococci also generates protective IL-17A+CD4+ TRM in the nasal mucosa. These results demonstrate a critical and sufficient role of TRM in prevention of pneumococcal colonization, and further that these cells can be generated by parenteral immunization. Our findings therefore have important implications regarding the generation of immune protection at mucosal surfaces by vaccination.

2703. Pneumococcal Carriage of 13-Valent Pneumococcal Conjugate Vaccine (PCV13) and Non-PCV13 Serotypes among Greek Children Vaccinated with PCV13 in a 3 + 1 Schedule During the First 6 years after the Fourth Dose of PCV13

BackgroundWe evaluated the long-term impact of full PCV13 vaccination in a 3 + 1 schedule on pneumococcal colonization patterns of children in order to clarify PCV13 serotype persistence/enhancement and re-colonization.MethodsFrom January 18 to August 29, 2017, consecutive children who had received the 4-dose course of PCV13, as per the National Immunization Program recommendations, were prospectively enrolled through 45 general pediatric practice facilities in 30 municipalities in Greece. A single oropharyngeal sample was obtained from each subject in a standardized manner (questionnaire, procedure). Based on the time interval since the fourth dose of PCV13, the children sampled were grouped for analysis in 6 groups: 26 days to 11 months; 12–23 months; 24–35 months; 36–47 months; 48–59 months, and 60–71 months. Carriage and distribution of Streptococcus pneumoniae serotypes was detected by RT–PCR.ResultsA total of 1212 children aged 14–83 months were investigated. S. pneumoniae was identified in the pharyngeal swab of 617 children (50.9%); 172/617 (27.9%) children carried > 1 pneumococcal serotypes. As a consequence of co-colonization, a total number of 718 S. pneumoniae (belonging to 28 serotypes) was identified. The carriage rate of non-PCV13 serotypes escalated within 3 years after the fourth dose and plateaued during the fourth and fifth year. The carriage rate of PCV13 serotypes escalated during the 4 years after the fourth dose and declined thereafter. 22/305 children (7.2%) carried one or more PCV13 serotypes in the first year after the fourth vaccine dose, 27/201 (13.4%) in the second year, 34/207 (16.4%) in the third year, 48/224 (21.4%) in the fourth year, 40/191 (20.9%) in the fifth year and 13/84 (15.5%) in the sixth year (P < 0.0001) (Figure 1). The colonization frequency of serotypes 3 and 19A increased with the rise of the vaccination time interval (Figure 2). Changes in the frequency of other PCV13 serotypes were not significant. Serotypes 7F, 14 and 23F were not recovered.ConclusionOur study suggests that S. pneumoniae is present in the pharynx of children 26 days to 71 months after the completion of PCV13 vaccination, and that non-PCV13 serotypes predominate throughout this period. The carriage rate of PCV13 serotypes 3 and 19A increases significantly as the time interval from the fourth dose of PCV13 increases. Disclosures All authors: No reported disclosures.

Pneumococcal carriage among children under five in Accra, Ghana, five years after the introduction of pneumococcal conjugate vaccine

BackgroundThe study objective was to determine the carriage and serotype distribution of Streptococcus pneumoniae among children in Accra, Ghana, five years after the introduction of the pneumococcal conjugate vaccine (PCV-13) in 2012.MethodsNasopharyngeal swab samples were collected from 410 children below 5 years of age in Accra, Ghana, from September to December, 2016. Pneumococcal isolates were identified by optochin sensitivity and bile solubility. Serotyping was performed using the latex agglutination kit and Quellung reaction. The isolates were furthermore tested for antimicrobial susceptibility for different antimicrobials, including penicillin (PEN). Twelve isolates including seven non-typeable (NT) isolates were characterized using whole-genome sequencing analysis (WGS).ResultsThe overall carriage prevalence was found to be 54% (95% CI, 49–59%), and 20% (95% CI, 49–59%) of the children were carrying PCV-13 included serotypes, while 37% (95% CI, 33–42%) of the children were carrying non-PCV-13 serotypes. Based on the serotype distribution, 33% of all observed serotypes were included in PCV-13 while 66% were non-PCV-13 serotypes. The dominating non-PCV-13 serotypes were 23B, 16F, and 11A followed by PCV-13 serotypes 23F and 19F. The PCV-13 covers the majority of resistant isolates in Accra. A proportion of 22.3% of the isolates showed intermediate resistance to penicillin G, while only one isolate showed full resistance. Forty-five isolates (20.5%) were defined as multidrug-resistant (MDR) as they were intermediate/resistant to three or more classes of antimicrobials. Of the seven NT isolates characterized by WGS, four showed highest match to genotype 38, while the remaining three showed highest match to genotype 14. Four MDR serotype 19A isolates were found to be MLST 320.ConclusionPCV-13 introduced in Ghana did not eliminate PCV-13 covered serotypes, and the carriage rate of 54% in this study is similar to carriage studies from pre PCV-13 period. However, the penicillin non-susceptible isolates have been reduced from 45% of carriage isolates before PCV-13 introduction to 22.3% of the isolates in this study. Continuous monitoring of serotype distribution is important, and in addition, an evaluation of an alternative vaccination schedule from 3 + 0 to 2 + 1 will be important to consider.

Long-term effect of 10-valent pneumococcal conjugate vaccine on nasopharyngeal carriage of Streptococcus pneumoniae in children in Brazil

Brazil introduced the 10-valent pneumococcal vaccine (PCV10) to the routine national immunization program (NIP) in March 2010. In 2017, we investigated the effects of PCV10 on nasopharyngeal carriage of vaccine-types (VT) and non-vaccine-types (NVT) of Streptococcus pneumoniae (Spn) among children living in São Paulo city. We also compared the prevalence of VT and NVT with previous carriage surveys performed in 2010 (baseline) and 2013. MethodThe carriage survey was conducted among 531 children, aged 12 months to <24 months, recruited from public Primary Health Units during the immunization campaign, using previous surveys methodology, except for qPCR, which was performed in the 2017 survey only. ResultsNo statistical difference was found in the prevalence of Spn either by culture (59.7%) or by qPCR (61.2%). Spn carriage increased from 40.3% (baseline) to 59.7% (2017 survey) (p < 0.001). Colonization by VT isolates significantly decreased by 90.9% (19.8–1.8%) and 95.5% (19.8–0.9%) in the 2013 and 2017 surveys, respectively, compared to that at baseline. NVT isolates increased significantly by 128% (19.6–44.8%) and 185% (19.6–55.9%) in the respective post-PCV10 surveys, most led to high prevalence of serotypes 6C (27%), 15B (9.8%), 19A (9.2%), 15A (6.0%), and 16F (5.7%). In 2017, reduction in serotype 6A (4.2–0.6%, p < 0.001) and increase in serotype 19A (1.8–6.0%, p = 0.001) were found; serotype 3 isolate was not detected in the present survey. We identified the emergence of 19A isolates CC320, associated with high penicillin (MIC ≥ 2.0 mg/L) and cefotaxime (MIC ≥ 1.0 mg/L) values. ConclusionAfter 7 years of PCV10 introduction in the NIP, colonization by VT among toddlers decreased substantially to a residual level, along with substantial serotype replacement by novel serotypes not present in any current conjugated pneumococcal vaccine and serotype 19A. The present findings can assist policy decisions in Brazil.

Prevalence of nasopharyngeal carriage of Streptococcus pneumoniae in children 7 to 14 years in 2016: A survey before pneumococcal conjugate vaccine introduction in Iran

ABSTRACT Streptococcus pneumoniae is a common cause of community-acquired pneumonia, meningitis, and otitis media in children. The aim of this study was to determine the prevalence of nasopharyngeal carriage of Streptococcus pneumoniae among children in the city of Hamadan, west of Iran. In this cross-sectional study, 532 students aged 7 to 14 years old from Hamadan were enrolled during the period from February to April 2016. Children were recruited using multi-stage sampling method. Informed consent form was obtained from parents of children. A researcher developed checklist was completed for every child by interviewer and samples of the throat of children were taken by swap method from the nasopharyngeal area. Descriptive statistics and chi square test were used to describe the study population. This study was approved by the Committee on Ethics of Hamadan University of Medical Sciences (IR.UMSHA.REC.1394.66). Prevalence of nasopharyngeal carriage of S. pneumoniae in children was 12.03% (95%CI: 9.38–15.10). About 37% (196 persons) of study population were male and 63% were female. Sixty four percent (345 people) of the studied population were from district two in Hamadan and others from District one. Prevalence of nasopharyngeal carriage of S. pneumoniae by sex was 13.77% (95% CI: 9.27–19.40) in males and 11.02 % (95% CI: 7.87–14.85) in females (P = 0.345). Considering the high prevalence of nasopharyngeal carriage of Streptococcus pneumoniae in children studied in Hamadan, pneumococcal conjugate vaccine (PCV) is recommended to be integrated into the Iran’s National Immunization Program.

Nasopharyngeal carriage of Streptococcus pneumoniae serotypes among children in India prior to the introduction of pneumococcal conjugate vaccines: a cross-sectional study

BackgroundStreptococcus pneumoniae is a major cause of pneumonia, meningitis, and other serious infections among children in India. India introduced the 13-valent pneumococcal conjugate vaccine (PCV) in several states in 2017, and is expected to expand to nationwide coverage in the near future. To establish a baseline for measuring the impact of PCV in India, we assessed overall and serotype-specific nasopharyngeal carriage in two pediatric populations.MethodsA cross-sectional study was conducted in Palwal District, Haryana, from December 2016 to July 2017, prior to vaccine introduction. Children 2–59 months of age with clinical pneumonia seeking healthcare and those in the community with no clear illness were targeted for enrollment. A nasopharyngeal swab was collected and tested for pneumococcus using conventional culture and sequential multiplex PCR. Isolates were tested for antimicrobial resistance using an E test. Children were considered colonized if pneumococcus was isolated by culture or PCR. The prevalence of pneumococcal and serotype-specific colonization was compared between groups of children using log-binomial regression.ResultsAmong 601 children enrolled, 91 had clinical pneumonia and 510 were community children. The proportion colonized with S. pneumoniae was 74.7 and 54.5% among children with clinical pneumonia and community children, respectively (adjusted prevalence ratio: 1.38; 95% confidence interval: 1.19, 1.60). The prevalence of PCV13 vaccine-type colonization was similar between children with clinical pneumonia (31.9%) and community children (28.0%; p = 0.46). The most common colonizing serotypes were 6A, 6B, 14, 19A, 19F, and 23F, all of which are included in the PCV13 vaccine product. Antimicrobial resistance to at least one drug was similar between isolates from children with clinical pneumonia (66.1%) and community children (61.5%; p = 0.49); while resistance to at least two drugs was more common among isolates from children with clinical pneumonia (25.8% vs. 16.4%; p = 0.08). Resistance for all drugs was consistently higher for PCV13 vaccine-type serotypes compared to non-vaccine serotypes in both groups.ConclusionThis study provides baseline information on the prevalence of serotype-specific pneumococcal colonization among children prior to the introduction of PCV in India. Our results suggest a role for pneumococcal vaccines in reducing pneumococcal colonization and antimicrobial resistant isolates circulating in India.

Pneumococcal carriage, density, and co-colonization dynamics: A longitudinal study in Indonesian infants

ObjectivesNasopharyngeal carriage of Streptococcus pneumoniae underpins disease development and transmission. This study was performed to examine pneumococcal carriage dynamics, including density and multiple serotype carriage, in Indonesian infants during the first year of life. MethodsTwo hundred healthy infants were enrolled at 2 months of age. Eight nasopharyngeal swabs were collected from enrolment until 12 months of age. Pneumococci were detected using quantitative PCR and serotyped by microarray. Regression models assessed factors influencing pneumococcal carriage and density. ResultsEighty-five percent of infants carried pneumococci at least once during the study. The median age at first acquisition was 129 days (interquartile range 41–216 days). The median duration of carriage was longer for the first pneumococcal acquisition compared with subsequent acquisitions (151 days vs. 95 days, p<0.0001). Of the 166 infants who carried pneumococci during the study, the majority (63.9%) carried a single pneumococcal serotype at a time. Pneumococcal carriage density was higher when upper respiratory tract infection symptoms were present, lower during antibiotic usage, decreased with age, and tended to decrease over time during a carriage episode. ConclusionsThe majority of Indonesian infants carry pneumococcus at least once during the first year of life. Pneumococcal carriage is a dynamic process, with pneumococcal density varying during a carriage episode.

Pneumococcal carriage in children in Ulaanbaatar, Mongolia before and one year after the introduction of the 13-valent pneumococcal conjugate vaccine

BackgroundNasopharyngeal carriage of Streptococcus pneumoniae precedes disease, is the source of pneumococcal community spread, and the mechanism for herd protection provided by pneumococcal conjugate vaccines (PCVs). There are few PCV impact studies in low- and middle-income countries, particularly in Asia. In 2016, Mongolia introduced the 13-valent PCV (PCV13) in a phased manner using a 2 + 1 schedule, with catch-up. We aimed to assess the impact of PCV13 introduction on nasopharyngeal pneumococcal carriage and density in children in Mongolia. MethodsWe conducted two cross-sectional carriage surveys (pre- and one year post-PCV) at community health clinics in two districts of the capital city, Ulaanbaatar in both May-July 2015 and 2017. The study analysis included 961 children too young to be vaccinated (5–8 weeks old) and 989 children eligible for vaccination (12–23 months old). Pneumococci were detected by quantitative real-time PCR and molecular serotyping performed using DNA microarray. FindingsOne year post-PCV introduction, PCV13 serotype carriage reduced by 52% in 12–23 month olds (adjusted prevalence ratio [aPR] 0.48 [95% confidence interval [CI] 0.39–0.59]), with evidence of non-PCV13 serotype replacement (aPR 1.55 [95% CI 1.30–1.85]), compared with the pre-PCV period. In 5–8 week olds, PCV13 serotype carriage reduced by 51% (aPR 0.49 [95% CI 0.33–0.73]) with no significant change in non-PCV13 serotype carriage (aPR 1.10 [95% CI 0.83–1.46]). An increase was observed in both PCV13 and non-PCV13 pneumococcal density post-PCV introduction. Antimicrobial resistance (AMR) genes were common, with 82.3% of samples containing at least one of the 10 AMR genes assessed. ConclusionThis study demonstrates substantive PCV13 impact on pneumococcal carriage one year post-vaccine introduction in Mongolia. The reductions in PCV13 serotype carriage are likely to result in reductions in pneumococcal disease including indirect effects. Increases in non-PCV13 serotypes require further monitoring.

Impact of PCV7 vaccination on nasopharyngeal carriage and antimicrobial resistance among children in Turkey.

We aimed to evaluate the effects of 7-valent pneumococcal conjugate vaccine on nasopharyngeal carriage of Streptococcus pneumoniae and antibiotic resistance in children in a well-child clinic in a tertiary children's hospital in Turkey. We collected nasopharyngeal (NP) specimens from 557 two-month-old babies before vaccination. After the study population had received PCV7, NP samples were obtained from 135 babies. Antimicrobial susceptibility testing and serotyping were performed. S. pneumoniae colonized in 48 (8.6%) of the 557 two-month-old babies before vaccination. The follow-up cohort consisted of 135 subjects. The prevalence of PCV7 strain decreased from 33.3% to 19.3% after vaccination. However, non-PCV7 types increased from 66.6% to 80.6% (p = 0.02). Of PCV7 serotypes, 19F was the most frequent serotype before and after vaccination. There was an increase in 6A and 15 of non-PCV7 serotypes after vaccination. Penicillin non-susceptible increased from 56.3% to 80.6% after vaccination (p =0.03). Serotypes 14, 18C, 9V and 6B, which were identified before vaccination, never colonized afterwards. Number of siblings and having sibling with older age of five were determined to be significant effective factors for SP colonization presence after vaccination and antibiotic use was negatively associated with pneumococcal carriage but associated with penicillin non-susceptibility. Nasopharyngeal carriage rate of S. pneumoniae dropped after PCV7 vaccination, and replacement by NVT pneumococci were also observed. Risk factors for nasopharyngeal carriage included household crowding and having a sibling age five years or older. Penicillin non-susceptibility increased in both VT and NVT strains.

PCV7- and PCV10-Vaccinated Otitis-Prone Children in New Zealand Have Similar Pneumococcal and Haemophilus influenzae Densities in Their Nasopharynx and Middle Ear.

Otitis media (OM) is a major reason for antibiotic consumption and surgery in children. Nasopharyngeal carriage of otopathogens, Streptococcus pneumoniae and nontypeable Haemophilus influenzae (NTHi), is a prerequisite for development of OM, and increased nasopharyngeal otopathogen density correlates with disease onset. Vaccines can reduce or eliminate otopathogen carriage, as demonstrated for pneumococcal serotypes included in pneumococcal conjugate vaccines (PCV). The 10-valent PCV (PCV10) includes an NTHi carrier protein, and in 2011 superseded 7-valent PCV on the New Zealand Immunisation Program. Data are conflicting on whether PCV10 provides protection against NTHi carriage or disease. Assessing this in otitis-prone cohorts is important for OM prevention. We compared otopathogen density in the nasopharynx and middle ear of New Zealand PCV7-vaccinated and PCV10-vaccinated otitis-prone and non-otitis-prone children to determine PCV10 impact on NTHi and S. pneumoniae carriage. We applied qPCR to specimens collected from 217 PCV7-vaccinated children (147 otitis-prone and 70 non-otitis-prone) and 240 PCV10-vaccinated children (178 otitis-prone and 62 non-otitis-prone). After correcting for age and day-care attendance, no difference was observed between NTHi density in the nasopharynx of PCV7-vaccinated versus PCV10-vaccinated otitis-prone (p = 0.563) or non-otitis-prone (p = 0.513) children. In contrast, pneumococcal nasopharyngeal density was higher in PCV10-vaccinated otitis-prone children than PCV7-vaccinated otitis-prone children (p = 0.003). There was no difference in otopathogen density in middle ear effusion from PCV7-vaccinated versus PCV10-vaccinated otitis-prone children (NTHi p = 0.918; S. pneumoniae p = 0.415). When pneumococcal carriage was assessed by vaccine serotypes (VT) and non-vaccine serotypes (NVT), there was no difference in VT density (p = 0.546) or NVT density (p = 0.315) between all PCV7-vaccinated versus all PCV10-vaccinated children. In summary, PCV10 did not reduce NTHi density in the nasopharynx or middle ear, and was associated with increased pneumococcal nasopharyngeal density in otitis-prone children in New Zealand. Development of therapies that prevent or reduce otopathogen colonisation density in the nasopharynx are warranted to reduce the burden of OM.

Carriage of Streptococcus pneumoniae in ages 2–4 years in the winter season of 2017-2018 in the local cities of Jordan

Carriage of Streptococcus pneumoniae in ages 2–4 years in the winter season of 2017-2018 in the local cities of Jordan

Asymptomatic carriage of Streptococcus pneumoniae detected by qPCR on the palm of hands of populations in rural Senegal.

Aside from malaria, infectious diseases are an important cause of death in sub-Saharan Africa and continue to pose major public health problems in African countries, notably pneumonia. Streptococcus pneumoniae remains the most common bacterial cause of pneumonia in all age groups. The skin is one of the main infection sites followed by the oropharynx. The skin carriage of certain pathogenic bacteria such as S. pneumoniae is often ignored or under-diagnosed. Finally, the mode of transmission of these infections remains uncertain. Here, we hypothesized that skin could play a role in the transmission of these infections. We collected 649 cotton swabs from a healthy population in Dielmo and Ndiop, rural Senegal. The sampling was carried out on the palm of the hands. After DNA extraction and actin control, qPCR targeting eight different bacteria was performed on 614 skin samples. We detected Streptococcus pneumoniae in 33.06% (203/614), Staphylococcus aureus in 18.08% (111/614) and Streptococcus pyogenes in 1.95% (12/614) of samples. A skin S. pneumoniae carriage was detected in more than a third of a rural population in rural Africa, highlighting the need to develop hand disinfection programs in order to reduce the burden of infections.

Nasopharyngeal carriage of Streptococcus pneumoniae in children under 5 years of age before introduction of pneumococcal vaccine (PCV10) in urban and rural districts in Pakistan

BackgroundBenefits of pneumococcal conjugate vaccine programs have been linked to the vaccine’s ability to disrupt nasopharyngeal carriage and transmission. The 10-valent pneumococcal vaccine (PCV10) was included in the Expanded Program on Immunization (EPI) in Sindh, Pakistan in February 2013. This study was carried out immediately before PCV10 introduction to establish baseline pneumococcal carriage and prevalent serotypes in young children and to determine if carriage differed in urban and rural communities.MethodsNasopharyngeal specimens were collected from a random sample of children 3-11 and 12-59 months of age in an urban community (Karachi) and children 3-11 months of age in a rural community (Matiari). Samples were processed in a research laboratory in Karachi. Samples were transported in STGG media, enriched in Todd Hewitt broth, rabbit serum and yeast extract, cultured on 5% sheep blood agar, and serotyped using the CDC standardized sequential multiplex PCR assay. Serotypes were categorized into PCV10-type and non-vaccine types.ResultsWe enrolled 670 children. Pneumococci were detected in 73.6% and 79.5 % of children in the infant group in Karachi and Matiari, respectively, and 78.2% of children 12 to 59 months of age in Karachi. In infants, 38.9% and 33.5% of those carrying pneumococci in Karachi and Matiari, respectively, had PCV10 types. In the older age group in Karachi, the proportion was 30.7%, not significantly different from infants. The most common serotypes were 6A, 23F, 19A, 6B and 19F.ConclusionWe found that about 3 of 4 children carried pneumococci, and this figure did not vary with age group or urban or rural residence. Planned annual surveys in the same communities will inform change in carriage of PCV10 serotype pneumococci after the introduction and uptake of PCV10 in these communities

Probiotics and carriage of Streptococcus pneumoniae serotypes in Danish children, a double-blind randomized controlled trial

This study examined the carriage of Streptococcus pneumoniae in healthy Danish children aged 8–19 months and assessed the effect of the probiotics Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp lactis on the pneumococcal carriage during daycare enrolment. Potential risk factors of pneumococcal carriage were analysed and the carriage study was compared with registered invasive pneumococcal disease (IPD) data. This study is a part of the ProbiComp study, which was a double-blind, randomized controlled trial, including 290 children allocated to probiotics or placebo for 6 months and recruited during two autumn seasons (2014/2015). Pneumococci were identified by optochin sensitivity, bile solubility, α-hemolysis and/or capsular reaction. Serotyping was performed by latex agglutination kit and Quellung reaction. The carriage rate of S. pneumoniae was 26.0% at baseline and 67.4% at the end of intervention. No significant difference was observed between the placebo group and the probiotics group (p = 0.508). Children aged 8–19 months were carriers of non-pneumococcal vaccine serotypes causing IPD in children aged 0–4 years. However, serotypes causing most IPD cases in Danish elderly were either not found or found with low prevalence suggesting that children are not the main reservoir of those serotypes and other age groups need to be considered as carriers.