Longitudinal investigation of nasopharyngeal pneumococcal carriage in early childhood: The PATCH birth cohort study

Outcomes of pediatric community-acquired pneumonia before and after national pneumococcal immunization in Taiwan

OBJECTIVE

In Taiwan, the incidence of invasive pneumococcal disease (IPD) in children declined after the catch-up primary vaccination programs and the full national immunization program (NIP) with PCV13. The objective of the study was to investigate the clinical outcomes of pediatric community-acquired pneumonia (CAP) before and after the NIP.

METHODS

The study included patients aged 3 months to 17 years who were diagnosed with CAP and treated at the National Taiwan University Hospital between 2007 and 2019. Patients were assigned to three birth cohorts according to their birth years and vaccination eligibility: non-NIP, catch-up, and full NIP. We compared the rates of severe outcomes, including case fatality and pathogens.

RESULTS

A total of 6557 patients who met the CAP criteria were enrolled during the study period. The case-fatality rate decreased from 3.2% (94/2984) in the non-NIP cohort to 0.3% (7/2176) in the catch-up cohort and 0.8% (11/1397) in the full NIP cohort (p < 0.001). Furthermore, there was a significant decrease in invasive ventilation from the non-NIP (17.9%) to both catch-up (6.8%) and full NIP cohorts (9.1%). The rate of IPD declined from the non-NIP cohort to the catch-up cohort (1.8% vs. 0.6%, p < 0.001) and from the catch-up to the full NIP cohort (0.6% vs. 0.07%, p = 0.014). In contrast, the rates of infections with other pathogens increased after NIP.

CONCLUSION

The introduction of PCV13 showed significant reduction in case-fatality and IPD rates. The increasing rates of other pathogens warrant further surveillance for their clinical significance.

Clinical Presentation and Co-Detection of Respiratory Pathogens in Children Under 5 Years with Non-COVID-19 Bacterial and Viral Respiratory Tract Infections: A Prospective Study in Białystok, Poland (2021-2022)

BACKGROUND Respiratory tract infections (RTIs) in children often involve a complex interplay between viruses and bacteria. This study aimed to evaluate clinical presentation in children under 5 years old diagnosed with non-COVID-19 bacterial and viral respiratory tract co-infections between October 2021 and May 2022 in Białystok, Poland. MATERIAL AND METHODS We recruited 100 children under 5 years with RTIs who tested negative for SARS-CoV-2. Nasopharyngeal swabs were screened for 19 viruses and 7 bacterial strains using molecular assays. RESULTS Viral pathogens were detected in 71% of patients and bacterial pathogens were detected in 59%. The most common pathogens were Haemophilus influenzae (n=48), rhinoviruses (n=32), and Streptococcus pneumoniae (n=30). Single pathogens were detected in 36%, dual in 37%, triple in 15%, and quadruple in 2%. Bacterial pathogens were co-detected with viruses in 40 cases, mostly with rhinoviruses (n=15). Two different viruses were found in 14 children and the most common co-detection was adenovirus with rhinovirus (n=5); dyspnea (63% vs 11%) and wheezing (75% vs 22%) were more common in children with human bocavirus. Fever was a common symptom in children with human adenovirus (88% vs 58%). Detection of bacteria and multiple detections were more common in day-care attendees, but were not associated with clinical picture of RTI. CONCLUSIONS Consistent with previous studies, we found a high prevalence of rhinoviruses, despite ongoing implementation of non-pharmaceutical interventions to contain the COVID-19 pandemic. Co-detection of 2 different respiratory pathogens was frequent, but we found no evidence that this was associated with the severity of infections.

Pneumococcal serotypes and antibiotic resistance in healthy carriage children after introduction of PCV13 in Lima, Peru

OBJECTIVE

To determinate the frequency of Streptococcus pneumoniae nasopharyngeal carriers, serotypes and antimicrobial resistance in healthy children in Lima, Peru, post-PCV13 introduction and to compare the results with a similar study conducted between 2006 and 2008 before PCV7 introduction (pre-PCV7).

METHODS

A cross-sectional multicenter study was conducted between January 2018 and August 2019 in 1000 healthy children under two years of age. We use standard microbiological methods to determinate S. pneumoniae from nasopharyngeal swab, Kirby Bauer and minimum inhibitory concentration methods to determinate antimicrobial susceptibility and whole genomic sequencing to determinate pneumococcal serotypes.

RESULTS

The pneumococcal carriage rate was 20.8 % vs. 31.1 % in pre-PCV7 (p < 0.001). The most frequent serotypes were 15C, 19A and 6C (12.4 %, 10.9 % and 10.9 % respectively). The carriage of PCV13 serotypes after PCV13 introduction decreased from 59.1 % (before PCV7 introduction) to 18.7 % (p < 0.001). Penicillin resistance was 75.5 %, TMP/SMX 75.5 % and azithromycin 50.0 %, using disk diffusion. Penicillin resistance rates using MIC breakpoint for meningitis (MIC ≥ 0.12) increased from 60.4 % to 74.5 % (p = 0.001).

CONCLUSION

The introduction of PCV13 in the immunization program in Peru has decreased the pneumococcal nasopharyngeal carriage and the frequency of PCV13 serotypes; however, there has been an increase in non-PCV13 serotypes and antimicrobial resistance.

Longitudinal investigation of pathogenic bacterial colonization in early childhood: Emphasis on the determinants of Moraxella catarrhalis colonization

BACKGROUND

Moraxella catarrhalis is a common, potential pathogen colonizing the respiratory tract in children. However, there is little information regarding the determinants of M. catarrhalis colonization and disease development.

METHODS

A population-based cohort study was conducted to collect nasopharyngeal swabs from children aged 1, 2, 4, 6, 12, 18, 24, 36, and 60 months for the detection of four common respiratory tract pathogens, including Staphylococcus aureus, M. catarrhalis, Streptococcus pneumoniae, and Haemophilus influenzae. Questionnaires on breastfeeding status were administered during each visit.

RESULTS

A total of 921 children were enrolled between 2012 and 2018. S.aureus was the most common pathogen, although the rates declined during the initial 18 months of life; in contrast, the other three pathogens increased during the first 5 years of life. M. catarrhalis was the second most common colonizing pathogen in all age groups, with prevalence ranging from 0.8% (7/842) at one month to 20.4% (33/162) at 60 months of age. Breastfed children (odds ratio [OR]: 0.56; 95% confidence interval [CI]: 0.35-0.92; P = 0.02) had a lower potential for M. catarrhalis carriage; however, infants with a longer duration of exclusive breastfeeding (OR: 1.12; 95% CI: 1.01-1.25; P = 0.04), especially >12 months of age, had a higher rate of M. catarrhalis carriage.

CONCLUSION

Breastfeeding should be promoted because it may be correlated with a lower risk of M. catarrhalis carriage. However, an extended period of exclusive breastfeeding may be positively associated with M. catarrhalis colonization.

Distribution and Drug Resistance of Bacterial Pathogens Associated with Lower Respiratory Tract Infection in Children and the Effect of COVID-19 on the Distribution of Pathogens

By studying the distribution and drug resistance of bacterial pathogens associated with lower respiratory tract infection (LRTI) in children in Chengdu and the effect of the COVID-19 on the distribution of pathogens and by analyzing the epidemic trend and drug resistance changes of the main pathogens of LRTI, this research is supposed to provide a useful basis for the prevention of LRTI in children and the rational use of drugs in clinical practice. Hospitalized children clinically diagnosed with LRTI in Chengdu Women and Children's Central Hospital from 2011 to 2020 were selected as the study subjects. The pathogens of LRTI in children and the distribution of pathogens in different ages, genders, seasons, years, and departments and before and after the pandemic situation of COVID-19 were counted. The drug resistance distribution of the top six pathogens with the highest infection rate in the past three years and the trend of drug resistance in the past decade were analyzed. A total of 26,469 pathogens were isolated. Among them, 6240 strains (23.6%) were Gram-positive bacteria, 20152 strains (76.1%) were Gram-negative bacteria, and 73 strains (0.3%) were fungi. Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, and Staphylococcus aureus were highly isolated in the group of infants aged 0-1 (P < 0.01), Moraxella catarrhalis and Streptococcus pneumoniae were highly isolated in children aged 1–6 (P < 0.01), and Haemophilus influenzae was highly isolated in children over 1 (P < 0.01). The isolation rates of Enterobacteriaceae, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Staphylococcus aureus, and Candida albicans in the lower respiratory tract of 0-1 year-old male infants were higher than those of female infants (p < 0.05). Haemophilus influenzae was highly isolated in spring and summer, and Moraxella catarrhalis was highly isolated in autumn and winter, while the infection of Streptococcus pneumoniae was mainly concentrated in winter. This difference was statistically significant (P < 0.01). Affected by the COVID-19 pandemic, the isolation rates of Haemophilus influenzae and Streptococcus pneumoniae were significantly lower than those before the pandemic, and the isolation rate of Moraxella catarrhalis was significantly higher. The difference was statistically significant (P < 0.01). The proportion of isolated negative bacteria in NICU and PICU was higher than that in positive bacteria, and the infection rates of Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, and Acinetobacter baumannii were higher than those in other departments. The differences were statistically significant (P < 0.01). The results of drug sensitivity test showed that the drug resistance of Haemophilus influenzae and Moraxella catarrhalis was mainly concentrated in Ampicillin, First- and Second-generation cephalosporins, and Cotrimoxazole, with stable sensitivity to Third-generation cephalosporins, while the drug resistance of Streptococcus pneumoniae was concentrated in Macrolides, Sulfonamides, and Tetracyclines, with stable sensitivity to Penicillin. Staphylococcus aureus is highly resistant to penicillins and macrolides and susceptible to vancomycin. Enterobacteriaceae resistance is concentrated in cephalosporins, with a low rate of carbapenem resistance. From 2018 to 2020, 1557 strains of Staphylococcus aureus were isolated, of which 416 strains were MRSA, accounting for 27% of the isolates; 1064 strains of Escherichia coli were isolated, of which 423 strains were ESBL and 23 strains were CRE, accounting for 40% and 2% of the isolates, respectively; and 1400 strains of Klebsiella pneumoniae were isolated, of which 385 strains were ESBL and 402 strains were CRE, accounting for 28% and 29% of the isolates, respectively. Since 2011, the resistance of Escherichia coli and Klebsiella pneumoniae to Third-generation cephalosporins has increased, peaking in 2017, and has decreased after 2018, years after which carbapenem resistance has increased significantly, corresponding to an increase in the detection rate of Carbapenem-resistant Enterobacteriaceae CRE. Findings from this study revealed that there are significant differences in community-associated infectious pathogens before and after the COVID-19 pandemic, and there are significant age differences, seasonal epidemic trends, and high departmental correlation of pathogens related to lower respiratory tract disease infection in children. There was a significant gender difference in the isolation rate of pathogens associated with LRTI in infants under one year. Vaccination, implementation of isolation measures and social distance, strengthening of personal protective measures, aseptic operation of invasive medical treatment, hand hygiene, and environmental disinfection are beneficial to reducing community-associated pathogen infection, opportunistic pathogen infection, and an increase in resistant bacteria. The strengthening of bacterial culture of lower respiratory tract samples by pediatricians is conducive to the diagnosis of respiratory tract infections caused by different pathogens, contributing to the selection of effective drugs for treatment according to drug susceptibility results, which is important for the rational use of antibiotics and curbing bacterial resistance.

Community-Associated Methicillin-Resistant Staphylococcus Aureus Colonization in a Birth Cohort of Early Childhood: The Role of Maternal Carriage

Background: Methicillin-resistant Staphylococcus aureus (MRSA) colonization in infants may pose a risk for subsequent infection in children. The study aimed to determine S. aureus colonization patterns in infancy, and strain relatedness between maternal and infant colonization.

Methods: A prospective cohort study was conducted for nasopharyngeal S. aureus detection in neonates at delivery; in children at 1, 6, 12, 24, 36, and 60 months of age; and from mothers immediately after the delivery of their baby and when their child is 1 month old. A questionnaire for infants and mothers was administered at each planned visit.

Results: In total, 521 and 135 infant–mother dyads underwent nasopharyngeal swab collection at 1 month and immediately after delivery, respectively. Among the 521 dyads at 1 month of age, concordant S. aureus colonization was found in 95 dyads, including MRSA in 48.4% (46/95). No concordant MRSA carriage was present among the 135 dyads at delivery. The genetic relatedness of concurrent MRSA-colonized dyads showed that more than two-thirds (32/46 [69.6%]) had identical genotypes, mainly ST 59/PVL-negative/SCCmec IV. Infants aged 1 month had the highest incidence of S. aureus, and the trend declined to a nadir at the age of 12 months. Carrier mothers who smoked cigarettes may increase the risk of infant Staphylococcus colonization (odds ratio, 2.12; 95% confidence interval, 1.23–3.66; p < 0.01).

Conclusions: Maternal–infant horizontal transmission may be the primary source of MRSA acquisition in early infancy. The avoidance of passive smoking could be recommended for the prevention of S. aureus carriage.

Respiratory Colonization and Short-Term Temporal Changes in the Urinary Metabolome of Children

The human metabolome may vary based on age, over time, and in the presence of viral carriage and bacterial colonization—a common scenario in children. We used nuclear magnetic resonance spectroscopy to identify and quantify urinary metabolites of children without signs or symptoms of respiratory illness. A urine sample and two nasopharyngeal swabs were collected to test for respiratory viral pathogens and colonization by Streptococcus pneumoniae (Sp). Urine samples were collected at the initial visit, 24 h post-enrollment, and 10–14 days post-enrollment. Of the 122 children enrolled, 24% had a virus detected and 19.7% had Sp detected. Intraclass correlation coefficients demonstrated greater within-subject versus between-subject variability for all metabolites detected. In linear mixed models adjusted for age, time, history of asthma, Sp, and viruses, 1-methylnicotinamide was increased by 50% in children with Sp and decreased by 35% in children with rhinovirus/enterovirus. Children with Sp had 83% higher levels of trimethylamine-N-oxide compared with those without Sp. However, when adjusting for multiple comparisons, the association was no longer statistically significant. In conclusion, there appear to be short-term changes within the urinary metabolome of healthy children, but levels of metabolites did not statistically differ in children with viral carriage or Sp detected.

Nasopharyngeal carriage of Streptococcus pneumoniae in healthy children aged less than five years

PURPOSE

In Turkey, pneumococcal conjugate vaccine (PCV) was introduced to the national immunization program as PCV7 in 2008, and was replaced with PCV13 in 2011. The aim of the study was to demonstrate the pneumococcal carriage rate and the serotype distribution in healthy children under 5 years in Turkey who were vaccinated with PCV13.

METHODS

We conducted a cross-sectional study including the collection of questionnaire data and nasopharyngeal (NP) specimens among children aged <5 years from five centers from March 2019 to March 2020. Pneumococcal isolates were identified using optochin sensitivity and bile solubility. Serotyping was performed using a latex agglutination kit and Quellung reaction.

RESULTS

NP swab samples were collected from 580 healthy children. The observed overall carriage rate was 17.8%. None of the hypothesised predictors of S. pneumoniae carriage, except maternal education level was statistically significant (p = 0.017). High maternal education level appeared to decrease the risk (lower vs. higher maternal education OR: 1.992 [95% CI; 1.089-3.643], p = 0.025). The overall NP S. pneumoniae carriage prevalence for the PCV13-vaccinated children was 17.8% (103/580). The most common serotypes detected were serotype 15B (n = 10, 9.7%), serotype 23F (n = 9, 8.7%), serotype 23A (n = 9, 8.7%), serotype 11A (n = 7, 6.7%), serotype 19F (n = 5, 4.8%) and serotype 15F (n = 5, 4.8%). Of the isolates, 28 (27.2%) were in PCV13 vaccine strains (VSs), and 75 (72.8%) strains were non-VS. The serotype coverage rate was 27.2% for PCV13.

CONCLUSION

The overall S. pneumoniae carriage rate was higher than in earlier studies from Turkey. Post-vaccine era studies from around the world have reported a decrease in VS serotypes and a 'serotype replacement' to non-VS serotypes, as we determined in our study.