Streptococcus pneumoniae serotype epidemiology among PCV-10 vaccinated and unvaccinated children at Gertrude's Children's Hospital, Nairobi County: a cross-sectional study

Nasopharyngeal carriage of Streptococcus pneumoniae serotypes among sick and healthy children in northern India: A case-control study

BACKGROUND

Streptococcus pneumoniae is leading bacterial cause of community acquired pneumonia and according to World Health Organization, responsible for 14 % death in children. There is effective vaccine available against Streptococcus pneumoniae. Hence the primary objective was to isolate Streptococcus pneumoniae from nasopharyngeal swabs in children aged 2-59 months with and without community acquired pneumonia and to assess their serotypes.

METHODS

This case-control study was conducted in tertiary teaching institutes in northern India. Hospitalized children, aged 2-59 months, with World Health Organization-defined community acquired pneumonia were included as cases. Age matched healthy controls were recruited from immunization clinic. All enrolments were done after written informed parental consent. Nasopharyngeal swabs were taken from both cases and controls, and were cultured on 5 % sheep blood agar with gentamycin plate for growth of Streptococcus pneumoniae and incubated in a jar at 370 for 18-24 hrs. Quellung reaction test was used for serotyping.

RESULTS

From March 2017 to December 2022, 2693 children (1910 cases and 783 controls), were recruited. The median age of cases was 7 months and controls 10 months. Almost all the cases had received antibiotics prior to hospitalization. Streptococcus pneumoniae positivity in nasopharyngeal swab was 8.1 % in cases, of which 56.8 % were vaccine serotypes and 23.6 % in controls, of which 37.8 % were vaccine serotypes. Adjusted odds ratio of isolating vaccine serotypes among cases as compared to controls was 1.77 (95 % CI, 1.09-2.88).

CONCLUSION

Streptococcus pneumoniae isolation from nasopharyngeal was found to be in lower proportion in cases as compared to control, though colonization with vaccine serotypes was higher in cases as compared to control. Therefore, pneumococcal vaccine coverage must be increased to prevent community acquired pneumonia.

Molecular characterization of invasive Streptococcus pneumoniae clinical isolates from a tertiary children's hospital in eastern China

Streptococcus pneumoniae is a common opportunistic pathogen that causes invasive pneumococcal disease (IPD), especially in children. This study aimed to determine the prevalence and molecular characteristics of S. pneumoniae isolated from children with IPD. A total of 78 S. pneumoniae isolates from aseptic body fluids of 70 IPD patients were collected at the Children's Hospital of Nanjing Medical University (Jiangsu Province, China) during 2017-2021. Whole-genome sequencing technology was used to analyze the serotype, sequence type (ST), virulence, and antibiotic resistance of the 78 invasive S. pneumoniae clinical isolates. Our results showed that the pneumococcal infection rate declined after the COVID-19 outbreak in 2019. Serotypes 19F, 14, 6A, 23F, 19A, and 6B were the most common strains. The pneumococcal conjugate vaccine (PCV) 13 serotype coverage rate was 87.1%. All isolates were classified by multi-locus sequence typing (MLST) analysis into 27 different STs, including 3 novel STs (ST17941, ST17942, and ST17944) and 1 novel allele [recP (558)]. The most predominant ST was ST271, followed by ST320 and ST876. All isolates carried the following virulence genes: cbpG, lytB, lytC, pce (cbpE), pavA, slrA, plr (gapA), hysA, nanA, eno, piuA, psaA, cppA, iga, htrA (degP), tig (ropA), zmpB, and ply. All isolates were multidrug resistant and had high levels of resistance to macrolides, tetracyclines, and sulfonamides. Taken together, this study revealed extensive genetic diversity among S. pneumoniae isolates from a single Chinese hospital. Wearing masks, universal infant vaccination with PCV13, and the launch of recombinant protein vaccine development programs could reduce the burden of IPD in children. IMPORTANCE Invasive pneumococcal disease (IPD) caused by Streptococcus pneumoniae in children remains a global burden and should be given more attention due to the fact that the pneumococcal vaccine is not fully covered globally. The molecular epidemiological characteristics of S. pneumoniae are not so clear, especially in these years of COVID-19. In this study, we collected S. pneumoniae isolates from the aseptic body fluid of children with IPD from 2017 to 2021 in a tertiary children's hospital in China and revealed the extensive genetic diversity of these isolates. Most importantly, we first found that the rate of pneumococcal infection has declined since the COVID-19 outbreak in 2019, which means that wearing masks could reduce the transmission of S. pneumoniae. In addition, it was shown that universal infant vaccination with PCV13 seems essential for reducing the burden of IPD in children.

Structural, biosynthetic and serological cross-reactive elucidation of capsular polysaccharides from Streptococcus pneumoniae serogroup 28

Capsular polysaccharides (CPS) are the key virulent factors in the pathogenesis of Streptococcus pneumoniae. The previously unknown CPS structures of the pneumococcal serotype 28F and 28A were thoroughly characterized by NMR spectroscopy, chemical analysis and AF4-MALS-dRI. The following repeat unit structures were determined: -4)[α-l-Rhap-[4-P-2-Gro]]-(1-3)-α-d-Sug-[6-P-Cho]-(1-3)-β-l-Rhap-[2-OAc]-(1-4)-β-d-Glcp-(1-; 28F: Sug = Glcp, Mw: 540.5 kDa; 28A: Sug = GlcpNAc, Mw: 421.9 kDa; The correlation of CPS structures with biosynthesis showed that glycosyltransferase WciU in serotypes 28F and 28A had different sugar donor specificity toward α-d-Glcp and α-d-GlcNAcp, respectively. Furthermore, latex agglutination tests of de-OAc and de-PO₄ CPS were conducted to understand cross-reactions between serogroup 28 with factor antiserum 23d. Interestingly, the de-OAc 28F and 28A CPS can still weakly react with factor antiserum 23d, while de-PO₄ CPS did not react with factor antiserum 23d. This indicated that OAc group could affect the affinity and P-2-Gro was crucial for cross-reacting with factor antiserum 23d.

Prevalence of pneumonia and its associated factors among under-five children in East Africa: a systematic review and meta-analysis

Background

Pneumonia is defined as an acute inflammation of the Lungs’ parenchymal structure. It is a major public health problem and the leading cause of morbidity and mortality in under-five children especially in developing countries. In 2015, it was estimated that about 102 million cases of pneumonia occurred in under-five children, of which 0.7 million were end up with death. Different primary studies in Eastern Africa showed the burden of pneumonia. However, inconsistency among those studies was seen and no review has been conducted to report the amalgamated magnitude and associated factors. Therefore, this review aimed to estimate the national prevalence and associated factors of pneumonia in Eastern Africa

Methods

Using PRISMA guideline, we systematically reviewed and meta-analyzed studies that examined the prevalence and associated factors of pneumonia from PubMed, Cochrane library, and Google Scholar. Heterogeneity across the studies was evaluated using the Q and the I² test. A weighted inverse variance random-effects model was applied to estimate the national prevalence and the effect size of associated factors. The subgroup analysis was conducted by country, study design, and year of publication. A funnel plot and Egger’s regression test were used to see publication bias. Sensitivity analysis was also done to identify the impact of studies.

Result

A total of 34 studies with 87, 984 participants were used for analysis. The pooled prevalence of pneumonia in East Africa was 34% (95% CI; 23.80–44.21). Use of wood as fuel source (AOR = 1.53; 95% CI:1.30–1.77; I² = 0.0%;P = 0.465), cook food in living room (AOR = 1.47;95% CI:1.16–1.79; I² = 0.0%;P = 0.58), caring of a child on mother during cooking (AOR = 3.26; 95% CI:1.80–4.72; I² = 22.5%;P = 0.26), Being unvaccinated (AOR = 2.41; 95% CI:2.00–2.81; I² = 51.4%;P = 0.055), Child history of Acute Respiratory Tract Infection (ARTI) (AOR = 2.62; 95% CI:1.68–3.56; I² = 11.7%;P = 0.337) were identified factors of pneumonia.

Conclusion

The prevalence of pneumonia in Eastern Africa remains high. This review will help policy-makers and program officers to design pneumonia preventive interventions.