Nasopharyngeal Carriage Of Streptococcus Research Articles

Nasopharyngeal carriage of Streptococcus pneumoniae among healthy children in Kassena-Nankana districts of Northern Ghana

BackgroundPneumococcal vaccine immunizations may be responsible for alterations in serotype epidemiology within a region. This study investigated the pneumococcal carriage prevalence and the impact of the 13-valent pneumococcal conjugate vaccine (PCV-13) on circulating serotypes among healthy children in Northern Ghana.MethodsThis was a cross sectional study conducted in the Kassena-Nankana districts of Northern Ghana from November to December during the dry season of 2018. Nasopharyngeal swabs collected from 193 participants were cultured per standard microbiological protocols and pneumococcal isolates were serotyped using the latex agglutination technique and the capsular Quellung reaction test. We examined for any association between the demographic characteristics of study participants and pneumococcal carriage using chi-square test and logistic regression.ResultsOf the 193 participants that were enrolled the mean age was 8.6 years and 54.4% were females. The carriage rate among the participants was 32.6% (63/193), and twenty different serotypes were identified. These included both vaccine serotypes (VT), 35% (7/20) and non-vaccine serotypes (NVT), 65% (13/20). The predominant serotypes (34 and 11A), both of which were NVT, accounted for a prevalence of 12.8%. PCV-13 covered only 35% of serotypes identified whiles 40% of serotypes are covered by PPV 23.ConclusionPost-vaccination carriage of S. pneumoniae is high and is dominated by non-vaccine serotypes. There is therefore a need for the conduct of invasive pneumococcal disease surveillance (IPD) to find out if the high non-vaccine serotype carriage translates to disease. And in addition, a review of the currently used PCV-13 vaccine in the country would be considered relevant.

Nasopharyngeal Carriage of Streptococcus pneumoniae and Associated Factors among Children in Southwest Ethiopia

Background: In Ethiopia, Streptococcus pneumoniae is the predominant causative agent of pneumonia. About, 95% of bacterial pneumonia cases in under five years of children are caused by pneumococci. Objective: To assess the nasopharyngeal carriage of Streptococcus pneumoniae, its antibiotic susceptibility pattern, and associated factors among children in Southwest Ethiopia. Methods: A cross-sectional study was conducted from October 01, 2018, to December 30, 2018. A total of 293 children aged ≤15 years were included in the study using a systematic random sampling technique. A nasopharyngeal swab was collected using a sterile cotton swab and cultured on blood agar supplemented with 5μg/ml gentamicin. The antimicrobial susceptibility testing was performed using the Kirby-Bauer disc diffusion technique. Results: The ages of participants ranged from 5 months to 14 years. The carriage rate of Streptococcus pneumoniae was 74/293 (25.3%). Being within the age group <3 years, the habit of sleeping with parent(s)/guardians and numbers of rooms per household were significantly associated with pneumococcal carriage. Streptococcus pneumoniae showed the highest resistance to Tetracycline, 36 (48.65%), and Trimethoprim/sulfamethoxazole, 29 (39.2%), and was found to be susceptible to Chloramphenicol, 54 (77%), and Erythromycin, 38 (51.4%). Conclusion: The nasopharyngeal carriage rate of Streptococcus pneumoniae is considerably high. High antimicrobial resistance of Streptococcus pneumoniae against Tetracycline and Trimethoprim/sulfamethoxazole was observed. Living in a house with a single room, children’s habit of sleeping with parents/guardians and age are associated factors of high pneumococcal carriage. Strategies need to be designed to address the modifiable associated factors and the bacterium antibiotic resistance pattern should be monitored regularly.

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.

Nasopharyngeal Carriage of Streptococcus pneumoniae and Related Risk Factors in Children Attending Day Care Centers

Nasopharyngeal Carriage of Streptococcus pneumoniae and Related Risk Factors in Children Attending Day Care Centers

Prevalence and serotype distribution of nasopharyngeal carriage of Streptococcus pneumoniae in China: a meta-analysis

BackgroundTo explore the overall prevalence and serotype distribution of nasopharyngeal carriage of Streptococcus pneumoniae(S. pneumoniae) among healthy children.MethodsA search for pneumococcal nasopharyngeal carriage studies including children published up to July 31th, 2016 was conducted to describe carriage in China. The review also describes antibiotic resistance in and serotypes of S. pneumoniae and assesses the impact of vaccination on carriage in this region. Summary measures for overall prevalence, antibiotic resistance, and serotype distributions extracted from the analyzed data were determined with 95% confidence intervals (CIs) using random-effects models. Heterogeneity was assessed using I2 test statistics.ResultsThirty-seven studies were included in this review, and the majority of studies (64.9%) were located in the pre-introduction period of 7-valent pneumococcal conjugate vaccine (PCV7) in China. The pooled prevalence of S. pneumoniae nasopharyngeal carriage was 21.4% (95% CI: 18.3–24.4%). Carriage was highest in children attending kindergartens [24.5%, (19.7–29.3%)] and decreased with increasing age. Before the introduction of PCV7 into China, the prevalence of S. pneumoniae nasopharyngeal carriage was 25.8% (20.7–30.9%), the pooled carriage of S. pneumoniae sharply dropped into the 14.1% (11.3–16.9%) by PCV7 vaccination period (P < 0.001). Before the pneumococcal conjugate vaccine (PCV) was introduced in China, the penicillin resistance rate in S. pneumoniae isolated from healthy children was 31.9% (21.2–42.6%); however, this rate sharply decreased after the introduction of PCV7 in China [21.6%, (7.4–35.9%)], and the difference between the rates during these two time periods was statistically significant (P value <0.05). Serotypes 19F, 6A and 23F were the most commonly isolated. Meta-analysis of data from young children showed a pooled rate estimate of 46.6% (38.8–54.4%) for PCV7 vaccine coverage and 66.2% (58.6–73.8%) for PCV13 vaccine coverage.ConclusionsThe prevalence of nasopharyngeal carriage among children was high in China. PCV7 immunization was found to be associated with reduction of nasopharyngeal colonization of S. pneumoniae. Conjugate vaccination coverage was slightly affected by the introduction of PCV7 into China because of low vaccination rate. The government should implement timely adjusted conjugate vaccination strategies based on our findings.

Serotyping of Streptococcus pneumoniae Isolates from Nasopharyngeal Samples: Use of an Algorithm Combining Microbiologic, Serologic, and Sequential Multiplex PCR Techniques

We evaluated nasopharyngeal carriage of Streptococcus pneumoniae (pneumococci) in nine Alaskan communities and used an algorithm combining microbiologic, serologic, and sequential multiplex PCR (MP-PCR) techniques to serotype the isolates. After microbiological identification as pneumococci, isolates (n = 1,135) were serotyped using latex agglutination and Quellung tests (LA/Q) as well as a series of six sequential MP-PCR assays. Results from the two methods agreed for 94% (1,064/1,135) of samples. Eighty-six percent (61/71) of the discordant results were resolved. Discordant results occurred because (i) the MP-PCR gel was misread (31/61 [51%]), (ii) the LA/Q agglutination was misinterpreted (13/61 [21%]), (iii) two serotypes or sets of serotypes were identified by MP-PCR and only one of the two was identified by LA/Q (9/61 [15%]), (iv) different serotypes or sets of serotypes were identified by LA/Q and MP-PCR and both were correct (7/61 [11%]), and (v) the capsular polysaccharide locus (cps) did not amplify during the initial MP-PCR but was present upon retesting (1/61 [2%]). Overall, isolation of pneumococci followed by MP-PCR quickly and accurately identified pneumococcal serotypes in >97% of samples and made available isolates for additional tests such as antimicrobial susceptibility. Misinterpretation of the MP-PCR gel was identified as the main source of discordance. Increasing the number of MP-PCRs from six to seven and reducing the number of serotypes in each reaction may reduce this error. This method may be of use to laboratories characterizing large numbers of S. pneumoniae samples, especially when antimicrobial susceptibility data are needed.

Impact of Prevnar vaccination on nasopharyngeal carriage of Streptococcus pneumoniae in healthy children in New Caledonia

We assessed the impact of the heptavalent pneumococcal conjugate vaccine (PCV7) on the nasopharyngeal carriage of Streptococcus pneumoniae in healthy children aged 2 to 24 months, four years after its implementation in New Caledonia. The data were compared with those obtained, before the introduction of the vaccine, in the same target population From February to October 2008, 592 children were enrolled prospectively, regardless of their vaccinal status. Between 2002 and 2008, the prevalence of the overall pneumococcal carriage and of vaccine type carriage decreased significantly, respectively 52.3% to 42.1% (p < 10-3) and 46.9% to 22.2% (p < 10-3). This reduction was offset by an increase (20.8% to 29.0%, p = 0.013) of the carriage of non-vaccine type pneumococci with reduced susceptibility to penicillin (PRSP), notably the serotypes 15B (p=0.027) and 19A (p=0.001). This increase in PRSP carriage was marked in the Northern Province (p = 0.005) and among Melanesian children (p = 0.009). Surprisingly this increase was mainly attributed to the vaccine type 19F (p < 10-3). In conclusion, as expected, the PCV7 vaccine led to a decrease of the pneumococcal carriage and the replacement of vaccine strains by non vaccine strains, however increasingly resistant to penicillin. In the Northern Province, the increasing carriage of penicillin resistant 19F strains escaping the vaccine is of concern and justifies a further comprehensive analysis using MLST genotyping.

Enhanced protection against nasopharyngeal carriage of Streptococcus pneumoniae elicited by oral multiantigen DNA vaccines delivered in attenuated Salmonella typhimurium

Developing carrier systems and choosing appropriate antigens are essential steps in improving the safety and efficacy of Streptococcus pneumoniae DNA vaccines, which have enhanced the mucosal protection against nasopharyngeal colonization. In this study, we reconstructed a Salmonella-based balanced-lethal host-eukaryotic vector system, which was used as carrier to orally deliver the Streptococcus pneumoniae multiantigen DNA vaccines encoding psaA (pneumococcal surface adhesion A) and pspA' (N-terminal of pneumococcal surface protein A) genes. The results showed that the multiantigen DNA vaccines using the new vector system as carrier afforded better protection than the vaccination with injected intramuscularly (i.m.) against Streptococcus pneumoniae D39 colonization infection in BALB/c mice models. This finding has associated with a high level of sIgA in the nasal mucosa as well as systemic IgG antibodies and a shift toward a Th1-mediated immune response. These studies have demonstrated the feasibility and advantage of using the new Salmonella-based balanced-lethal host-eukaryotic vector system as carrier to deliver S. pneumoniae DNA vaccines.

Nasopharyngeal Carriage of Streptococcus pneumoniae in the elderly: a comparative assessment of detection methods

Nasopharyngeal Carriage of Streptococcus pneumoniae in the elderly: a comparative assessment of detection methods

Indirect effects of childhood pneumococcal vaccination on pneumococcal carriage among adults and older children in Australian Aboriginal communities

Nasopharyngeal carriage of Streptococcus pneumoniae in unimmunised adults and older children in three remote Australian Aboriginal communities was compared in 2002 and 2004. Universal childhood pneumococcal vaccination with a catch-up program was introduced in late 2001. Carriage prevalence across all age groups of pneumococcal serotypes included in the 7-valent vaccine was 10% in both 2002 and 2004 (12 and 30 months after introduction of vaccination). This carriage prevalence was lower than anticipated. It is likely that indirect effects of childhood vaccination occurred before the 2002 survey. To further assess indirect effects on carriage of childhood pneumococcal vaccination, data prior to 2002 are required. Between 12 and 30 months following introduction of conjugate pneumococcal vaccination, indirect effects on carriage were unchanged.

Changes in treatment strategies for acute otitis media after full implementation of the pneumococcal seven valent conjugate vaccine

Administration of the pneumococcal seven valent conjugate vaccine (PCV-7) results in significant reductions in the incidence of invasive pneumococcal disease and nasopharyngeal colonization rates; however, the reduction in the overall incidence of acute otitis media (AOM) is minimal. Despite an ongoing shortage of PCV-7 in the United States, during which children are receiving fewer doses at longer intervals than the recommended dosing schedule, the incidence of invasive pneumococcal disease in young children has continued to decrease. The purpose of this article is to review why the reported effect of PCV-7 on AOM infection rates does not match the reduction in invasive pneumococcal disease or the reduction in nasopharyngeal carriage of Streptococcus pneumoniae. The potential effect of a fully implemented PCV-7 schedule on AOM infections is calculated based on serotype-specific AOM reduction rates observed in clinical studies. Clinical success rates of various antimicrobials used in the treatment of AOM in children fully immunized with PCV-7 also are calculated based on projected PCV-7-induced changes in pathogen profiles and documented antimicrobial resistance rates. Questions regarding potential serotype substitution in children with AOM but not invasive pneumococcal disease, the increased incidence of infection with Haemophilus influenzae in children immunized with PCV-7 and the possibility of herd immunity also will be addressed. Although the majority of penicillin-nonsusceptible S. pneumoniae are included in PCV-7, AOM caused by these strains will not completely disappear, especially in children 24 months of age and younger. Consequently, clinicians must continue to consider penicillin-nonsusceptible pneumococci when prescribing antimicrobials for AOM.

Nasopharyngeal carriage of Streptococcus pneumoniae: a review of the potential role of pharmacokinetics and pharmacodynamics

Much antibiotic prescribing is based upon irrational practice rather than scientific principles. The advent and the better understanding of the pharmacokinetics and pharmacodynamics of antimicrobials are slowly leading to a change whereby antibiotics are prescribed with a better rationale. The fundamental understanding of the pharmacokinetics of the antimicrobial, for example how well it is absorbed, metabolized, distributed and eliminated from the body, should lead to an appreciation of the correct dosing interval. Pharmacodynamic factors, in particular, appreciation of the MIC of an antimicrobial for an infecting pathogen and whether time-independent or -dependent killing occurs, will also have a profound influence upon how an antimicrobial is used. This review attempts to consider these features as they apply to nasopharyngeal carriage of Streptococcus pneumoniae. The reason for the dosing and dosing frequency of a number of agents is discussed and an attempt is made to point the way to more judicious antibiotic prescribing so as to maximize clinical efficacy yet minimize the possibility of resistance emerging during therapy.

Short-Course, High-Dose Amoxicillin Better Against Pneumococcus

Asymptomatic nasopharyngeal carriage of Streptococcus pneumoniae in children can lead to severe clinical disease states including pneumonia,

Establishment of aStreptococcus pneumoniaenasopharyngeal colonization model in adult mice

Human nasopharyngeal carriage ofStreptococcus pneumoniaeconstitutes the major natural reservoir of pneumococci and is thought to be the prelude to virtually all pneumococcal disease. If carriage could be greatly reduced, pneumococcal transmission and disease could be largely eliminated. To facilitate the studies of mechanisms important in carriage and to identify immunogens that can elicit protection against carriage, we characterized an adult mouse model of nasopharyngeal carriage. Non-anaesthetized mice were inoculated intranasally with pneumococci in 10 μl of fluid. Nasopharyngeal carriage was observed with strains of capsular types 3, 4, 6A, 6B, 14, 19, and 23. Carriage was stable over time, and the numbers of pneumococci carried were relatively independent of inoculation dose; findings which indicate that the recovery of pneumococci from 1 day to 2 weeks post inoculation was dependent on colonization, rather than just temporary contamination. To ensure carriage in the largest percentage of mice, without causing sepsis or death, inoculations of 107colony forming units (cfu) should be used. In this model, carriage was generally observed without concomitant bacteremia or sepsis and carriage was observed even with strains that were avirulent when injected i.v. The model should be useful for the identification of protection-eliciting antigens, since intranasal immunization with heat-killed pneumococci or lysates of pneumococci protected against carriage.