Impact of pneumococcal conjugate vaccines introduction on antibiotic resistance of Streptococcus pneumoniae meningitis in children aged 5 years or younger, Israel, 2004 to 2016

Clinical features and antibiotic resistance in pediatric pneumococcal meningitis in Southern Vietnam, 2012-2023: A multicenter retrospective study

BACKGROUND

Streptococcus pneumoniae is a major cause of morbidity and mortality in children. This study investigates the clinical features, cerebrospinal fluid (CSF) findings, serotype distribution, and antibiotic resistance patterns in Vietnamese children aged 1-59 months with pneumococcal meningitis (PM).

METHODS

This retrospective study (2012-2023) was conducted at two tertiary pediatric hospitals in Ho Chi Minh City. CSF samples from probable bacterial meningitis (PBM) cases were analyzed using biochemistry, culture, and real-time polymerase chain reaction (rt-PCR). Serotyping and antibiotic-resistance genes were identified using quadriplex rt-PCR.

RESULTS

Among 2922 PBM cases, 155 (5.3 %) were confirmed as PM. Of these, 58.7 % occurred in children under one year and 62.6 % during the rainy season. Fever (98.1 %) and vomiting (67.7 %) were the most common symptoms. Infants under 12 months frequently exhibited nonspecific signs like convulsions (48.4 %) and bulging fontanels (34.1 %), while older children displayed classic symptoms such as neck stiffness (32.4 %) and behavioral changes (26.5 %). CSF analysis revealed turbid appearance, WBC ≥ 100 cells/mm³ (85.2 %), and protein ≥ 1 g/L (60.0 %) (p < 0.05). Severe outcomes were noted in 17.4 % of PM cases, with a 3.2 % fatality rate. The 13-valent pneumococcal conjugate vaccine (PCV13) serotypes caused 81.3 % of confirmed cases, predominantly serotypes 6 A/B (34.8 %) and 19 F (20.0 %). Among 137 isolates tested, high prevalence rates were observed for the pbp2b (68.6 %), mef(A)/erm(B) (93.4 %), and tetM (92.0 %) resistance genes. Additionally, 61.3 % of isolates showed multiple resistance genes, particularly in serotypes 6 A/B, 23 F, 9 V, and 13. Antibiotic resistance in non-PCV13 serotypes increased over time.

CONCLUSIONS

PM in Vietnamese children presents age-specific clinical presentations and is predominantly caused by highly resistant PCV13 serotypes. The rising resistance in non-PCV13 serotypes poses a formidable challenge in managing pneumococcal infections. These findings emphasize the urgent need for PCV introduction in the national immunization program and ongoing resistance surveillance.

Streptococcus pneumoniae serotypes and factors associated with antimicrobial resistance in Invasive pneumococcal disease cases in Latvia, 2012-2022

Background

Streptococcus pneumoniae is a major cause of Invasive pneumococcal disease (IPD), including bacteremic pneumonia, septicemia, and meningitis. The introduction of pneumococcal conjugate vaccines (PCVs) has significantly reduced the incidence of IPD caused by vaccine-covered serotypes. However, serotype replacement and antimicrobial resistance remain concerns. In Latvia, vaccination against pneumococcal disease was introduced into the NIP in 2010 with PCV7, later transitioning to PCV10 in 2012 and to PCV15 in 2024. This study aims is to determine the changes in S. pneumoniae antimicrobial resistance and its association with PCV10 serotypes in Latvia.

Materials and methods

We conducted a population-based cross-sectional study using IPD surveillance data from Latvia over an 11-year period (2012-2022). IPD cases were defined according to the European Union case definition. Serotyping and antimicrobial susceptibility testing were performed on isolates from normally sterile sites. We analyzed the differences in IPD incidence, serotype distribution, and antimicrobial resistance using chi-square tests and multivariable logistic regression was used to determine associations between antimicrobial resistance and risk factors.

Results

A total of 811 IPD cases were reported, with significant differences observed across the study period (p < 0.001). The most common serotypes were 3 and 19A. The proportion of IPD cases caused by PCV10 serotypes significantly decreased over the years, while cases caused by PCV13, PCV15, and PPPV23 serotypes increased. Antimicrobial susceptibility testing revealed resistance rates of 3.8% to penicillin, 5.4% to erythromycin, and 1.2% to cefotaxime/ceftriaxone. Erythromycin resistance showed significant variation over time (p = 0.016), decreasing from 7.1% in 2012 to 4.8% in 2022. Multivariable logistic regression indicated that IPD cases with S. pneumoniae PCV10 serotypes and meningitis were significantly associated with an increased likelihood of penicillin and erythromycin resistance.

Conclusion

The study highlights a decrease in erythromycin resistance in IPD cases over time and significant associations between PCV10 serotypes and meningitis in IPD cases and penicillin and erythromycin resistance. The findings underscore the importance of continuous surveillance of S. pneumoniae serotypes and antimicrobial resistance patterns to inform treatment guidelines and vaccination policies. Further research is needed to assess the long-term impact of the PCV15 vaccine on S. pneumoniae serotype distribution and resistance.

Clinical and economic burden of acute otitis media caused by Streptococcus pneumoniae in European children, after widespread use of PCVs-A systematic literature review of published evidence

BACKGROUND

Acute otitis media (AOM) is a common childhood disease frequently caused by Streptococcus pneumoniae. Pneumococcal conjugate vaccines (PCV7, PCV10, PCV13) can reduce the risk of AOM but may also shift AOM etiology and serotype distribution. The aim of this study was to review estimates from published literature of the burden of AOM in Europe after widespread use of PCVs over the past 10 years, focusing on incidence, etiology, serotype distribution and antibiotic resistance of Streptococcus pneumoniae, and economic burden.

METHODS

This systematic review included published literature from 31 European countries, for children aged ≤5 years, published after 2011. Searches were conducted using PubMed, Embase, Google, and three disease conference websites. Risk of bias was assessed with ISPOR-AMCP-NPC, ECOBIAS or ROBIS, depending on the type of study.

RESULTS

In total, 107 relevant records were identified, which revealed wide variation in study methodology and reporting, thus limiting comparisons across outcomes. No homogenous trends were identified in incidence rates across countries, or in detection of S. pneumoniae as a cause of AOM over time. There were indications of a reduction in hospitalization rates (decreases between 24.5-38.8% points, depending on country, PCV type and time since PCV introduction) and antibiotic resistance (decreases between 14-24%, depending on country), following the widespread use of PCVs over time. The last two trends imply a potential decrease in economic burden, though this was not possible to confirm with the identified cost data. There was also evidence of an increase in serotype distributions towards non-vaccine serotypes in all of the countries where non-PCV serotype data were available, as well as limited data of increased antibiotic resistance within non-vaccine serotypes.

CONCLUSIONS

Though some factors point to a reduction in AOM burden in Europe, the burden still remains high, residual burden from uncovered serotypes is present and it is difficult to provide comprehensive, accurate and up-to-date estimates of said burden from the published literature. This could be improved by standardised methodology, reporting and wider use of surveillance systems.

The metabolic, virulence and antimicrobial resistance profiles of colonising Streptococcus pneumoniae shift after PCV13 introduction in urban Malawi

Streptococcus pneumoniae causes substantial mortality among children under 5-years-old worldwide. Polysaccharide conjugate vaccines (PCVs) are highly effective at reducing vaccine serotype disease, but emergence of non-vaccine serotypes and persistent nasopharyngeal carriage threaten this success. We investigated the hypothesis that following vaccine, adapted pneumococcal genotypes emerge with the potential for vaccine escape. We genome sequenced 2804 penumococcal isolates, collected 4-8 years after introduction of PCV13 in Blantyre, Malawi. We developed a pipeline to cluster the pneumococcal population based on metabolic core genes into "Metabolic genotypes" (MTs). We show that S. pneumoniae population genetics are characterised by emergence of MTs with distinct virulence and antimicrobial resistance (AMR) profiles. Preliminary in vitro and murine experiments revealed that representative isolates from emerging MTs differed in growth, haemolytic, epithelial infection, and murine colonisation characteristics. Our results suggest that in the context of PCV13 introduction, pneumococcal population dynamics had shifted, a phenomenon that could further undermine vaccine control and promote spread of AMR.

The impact of the introduction of ten- or thirteen-valent pneumococcal conjugate vaccines on antimicrobial-resistant pneumococcal disease and carriage: A systematic literature review

Background

A systematic review in 2019 found reductions in antimicrobial resistance (AMR) of pneumococcal vaccine serotypes following pneumococcal conjugate vaccine (PCV) introduction. However, few low- or middle-income countries were included as not many had introduced higher valent PCVs (PCV10 or PCV13). The aim of our review is to describe AMR rates in these samples following the introduction of PCV10 or PCV13.

Methods

We conducted a systematic literature review of published papers that compared AMR for invasive pneumococcal disease (IPD), otitis media (OM) and nasopharyngeal carriage (NPC) samples following introduction of PCV10 or PCV13 to the pre-PCV period. Included studies published from July 2017 to August 2020 had a post-licensure observational study design and reported on our defined outcomes: IPD, OM, NPC and other (sputum or mixed invasive and non-invasive pneumococcal) isolates from people of all ages. Rates of AMR in the pre- and post-period were extracted.

Results

Data were extracted from 31 studies. Among IPD isolates, penicillin AMR rates following PCV10 or PCV13 introduction declined in 32% (n = 9/29) of included studies, increased in 34% (n = 10/29) and showed no change in 34% (n = 10/29). Cephalosporins AMR declined in 32% (n = 6/19) of studies, increased in 21% (n = 4/19) and showed no change in 47% (n = 9/19). Macrolides AMR declined in 33% (n = 4/12) of studies, increased in 50% (n = 6/12), and showed no change in 17% (n = 2/12). AMR to other antibiotics (including multidrug resistance) declined in 23% (n = 9/39) of studies, increased in 41% (n = 16/39) and showed no change in AMR in 36% (n = 14/39). There were no obvious differences between AMR; in setting which used PCV10 vs PCV13, according to time since PCV introduction or by World Bank income status of the respective country. The only study including OM isolates found no change in penicillin resistance. There were few studies on AMR in NPC (four studies), OM (one study) or other isolates (five studies). The results followed similar patterns to IPD isolates.

Conclusions

We observed considerable heterogeneity in the findings between and within studies, e.g. no evidence of reduction in amoxicillin AMR with an increase in macrolides AMR. Reasons for such diverse findings include the period covered by different studies and variation in other pressures towards AMR.

Characteristics of endovascular pneumococcal infections; a decade of nationwide surveillance study

In order to characterize pneumococcal endovascular infection in the post-vaccination era, a retrospective nationwide study based on the Israeli Adult IPD database was conducted. Between 2010 and 2019, 0.6% (23 cases) of IPD cases were of endovascular type, occurring mainly in males (72.3%) with underlying medical conditions (78.2%). Additional pneumococcal source (10 patients) and concomitant infections were not uncommon. Penicillin and ceftriaxone susceptibility rates were 65.2% and 91.3%, respectively; 60.9% of the isolates were not covered by the pneumococcal conjugate vaccine. 21.7% of patients died during hospitalization. In conclusion, pneumococcal endovascular infections still carry significant morbidity and mortality.

Clinical and Bacteriological Analysis of Pediatric Pneumococcal Meningitis after 13-Valent Pneumococcal Conjugate Vaccine Introduction in Japan

Streptococcus pneumoniae is one of the leading causes of meningitis in children. In Japan, since the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13), the number of pneumococcal meningitis due to non-PCV13 serotypes in children has increased. To clarify the clinical outcomes, serotype distributions, and antimicrobial susceptibility of isolated S. pneumoniae strains from pediatric pneumococcal meningitis, we clinically and bacteriologically analyzed 34 cases of pediatric pneumococcal meningitis that were reported after the PCV13 introduction era in Japan. The median age at diagnosis was 1 year (range: 3 months–13 years). Ten (29.4%) patients had underlying diseases. Twenty-nine (85.3%) patients had received at least one dose of any pneumococcal vaccine. Of the 34 patients with pneumococcal meningitis, 6 had sequelae, and 4 died. Nine (26.5%) strains were resistant to penicillin; five (15%) strains to meropenem, with an MIC of 0.5 μg/mL. All strains were susceptible to vancomycin and linezolid. Daptomycin’s MIC₅₀ was 0.064 μg/mL and MIC₉₀ was 0.094 μg/mL. Among the tested strains, only four were PCV13 serotypes. Penicillin-resistant S. pneumoniae was isolated from 30.0% of the patients with sequelae and death. Particularly, the proportion of serotype 10A in the sequelae and deceased cases was significantly higher than that in the complete recovery cases. We should carefully monitor the serotype and drug susceptibility of S. pneumoniae strains isolated from patients with meningitis after the PCV13 era and reconsider the treatment strategy to prepare against further drug-resistant pneumococcal strains.

IMPORTANCE We analyzed 34 cases of pediatric pneumococcal meningitis that were reported after the 13-valent pneumococcal conjugate vaccine (PCV13) introduction era in Japan. Our study revealed that pneumococcal meningitis in children was mainly caused by non-PCV13 serotypes; all cases with sequelae and death were caused by non-PCV13 serotypes. Moreover, all serotypes of penicillin resistant Streptococcus pneumoniae strains (26.5%; 9/34) were non-PCV13 serotypes. We also analyzed antimicrobial susceptibilities of glycopeptides, linezolid (LZD), and daptomycin (DAP) of isolated S. pneumoniae strains. All tested strains were susceptible to vancomycin, teicoplanin, LZD, and DAP. Especially. DAP demonstrated the best outcome among the tested antibiotics, with MIC₉₀ of 0.094 μg/mL. Pneumococcal meningitis in children continues to persist and is difficult to control with the current conjugate vaccines. Therefore, it is important to monitor the serotype and antimicrobial susceptibility of S. pneumoniae strains isolated from patients with meningitis and accordingly reconsider the treatment strategy.

Nasopharyngeal Carriage of Streptococcus pneumoniae Among Young Children in Haiti Before Pneumococcal Conjugate Vaccine Introduction

BACKGROUND

Streptococcus pneumoniae, or pneumococcus, is a leading cause of morbidity and mortality in children worldwide. Pneumococcal conjugate vaccines (PCV) reduce carriage in the nasopharynx, preventing disease. We conducted a pneumococcal carriage study to estimate the prevalence of pneumococcal colonization, identify risk factors for colonization, and describe antimicrobial susceptibility patterns among pneumococci colonizing young children in Port-au-Prince, Haiti, before introduction of 13-valent PCV (PCV13).

METHODS

We conducted a cross-sectional study of children aged 6-24 months at an immunization clinic in Port-au-Prince between September 2015 and January 2016. Consenting parents were interviewed about factors associated with pneumococcal carriage; nasopharyngeal swabs were collected from each child and cultured for pneumococcus after broth enrichment. Pneumococcal isolates were serotyped and underwent antimicrobial susceptibility testing. We compared frequency of demographic, clinical, and environmental factors among pneumococcus-colonized children (carriers) to those who were not colonized (noncarriers) using unadjusted bivariate analysis and multivariate logistic regression.

RESULTS

Pneumococcus was isolated from 308 of the 685 (45.0%) children enrolled. Overall, 157 isolates (50.8%) were PCV13 vaccine-type serotypes; most common were 6A (13.3%), 19F (12.6%), 6B (9.7%), and 23F (6.1%). Vaccine-type isolates were significantly more likely to be nonsusceptible to ≥1 antimicrobial (63.1% vs 45.4%, P = .002). On bivariate analysis, carriers were significantly more likely than noncarriers to live in a household without electricity or running water, to share a bedroom with ≥3 people, to have a mother or father who did not complete secondary education, and to have respiratory symptoms in the 24 hours before enrollment (P < .05 for all comparisons). On multivariable analysis, completion of the pentavalent vaccination series (targeting diphtheria, pertussis, tetanus, hepatitis B, and Haemophilus influenzae type b) remained significantly more common among noncarriers.

CONCLUSIONS

Nearly a quarter of healthy children surveyed in Haiti were colonized with vaccine-type pneumococcal serotypes. This baseline carriage study will enable estimation of vaccine impact following nationwide introduction of PCV13.

Dynamics of antimicrobial resistance of Streptococcus pneumoniae following PCV10 introduction in Brazil: Nationwide surveillance from 2007 to 2019

BACKGROUND

Brazil introduced 10-valent pneumococcal conjugate vaccine (PCV10) into its immunization program in 2010. We assessed antimicrobial susceptibility of Streptococcus pneumoniae (Spn) obtained from a national surveillance system for invasive pneumococcal diseases (IPD) before/after PCV10 introduction.

METHODS

Antimicrobial non-susceptible isolates were defined as intermediate or resistant. Minimum inhibitory concentrations (MICs) to penicillin and ceftriaxone were analyzed by year. Antimicrobial susceptibility rates were assessed for each three-year-period using the pre-PCV10-period as reference. Susceptibility of vaccine-types was evaluated for 2017-2019.

RESULTS

11,380 isolates were studied. Spn with penicillin ≥ 0.125 mg/L and ceftriaxone ≥ 1.0 mg/L decreased in the three-years after PCV10 introduction (2011-2013: penicillin, 28.1-22.5%; ceftriaxone, 11.3%-7.6%) versus pre-PCV10-years (2007-2009: penicillin, 33.8-38.1%; ceftriaxone, 17.2%-15.6%). After 2013, the proportion of Spn with those MICs to penicillin and ceftriaxone increased to 39.4% and 19.7% in 2019, respectively. Non-susceptibility to penicillin and ceftriaxone increased in 2014-2016, and again in 2017-2019 especially among children < 5 years with meningitis (penicillin, 53.9%; ceftriaxone, 28.0%); multidrug-resistance reached 25% in 2017-2019. Serotypes 19A, 6C and 23A were most associated with antimicrobial non-susceptibility.

CONCLUSIONS

Antimicrobial non-susceptible Spn decreased in the three-years after vaccination but subsequently increased and was associated with non-PCV10-types. Antimicrobial susceptibility surveillance is fundamental for guiding antibiotic therapy policies.

Invasive pneumococcal disease incidence in children and adults in France during the pneumococcal conjugate vaccine era: an interrupted time-series analysis of data from a 17-year national prospective surveillance study

BACKGROUND

The long-term benefits of pneumococcal conjugate vaccines (PCVs) remain unknown because of serotype replacement. We aimed to estimate the effect of PCV implementation on invasive pneumococcal disease incidence in France.

METHODS

We did a quasi-experimental interrupted time-series analysis using data from a French national prospective surveillance system. We included all invasive pneumococcal disease cases in children and adults from more than 250 participating hospitals between Jan 1, 2001, and Dec 31, 2017. The primary outcome was incidence of invasive pneumococcal disease (meningitis and non-meningitis) over time, analysed by segmented regression with autoregressive error. Isolates were serotyped by latex agglutination with antiserum samples.

FINDINGS

We included 75 903 patients with invasive pneumococcal disease, including 4302 (5·7%) children younger than 2 years and 37 534 (49·4%) adults aged 65 years or older. Before PCV7 implementation, the estimated monthly incidence of invasive pneumococcal disease was 0·78 cases per 100 000 inhabitants, which did not change significantly up to May, 2010. PCV13 implementation in 2010 was followed by a significant decrease in the incidence of invasive pneumococcal disease (-1·5% per month, 95% CI -2·2 to -0·8), reaching an estimated monthly incidence of 0·52 cases per 100 000 inhabitants in December, 2014. From January, 2015, the incidence rebounded (1·8% per month, 95% CI 1·0 to 2·6), reaching an estimated monthly incidence of 0·73 cases per 100 000 inhabitants in December, 2017. The estimated monthly incidence increased from 0·93 cases per 100 000 in December, 2014, to 1·73 cases per 100 000 in December, 2017, for children younger than 2 years, and from 1·54 cases per 100 000 in December, 2014, to 2·08 cases per 100 000 in December, 2017, for adults aged 65 years or older. The main non-PCV13 serotypes involved in the increase were 24F in young children and 12F, 22F, 9N, and 8 in adults aged 65 years or older.

INTERPRETATION

PCV13 implementation led to a major reduction in the incidence of invasive pneumococcal disease. However, a rebound in cases among children and adults since 2015, driven by several emerging non-PCV13 serotypes, jeopardises the long-term PCV benefits. These findings, if confirmed in the coming years, should be considered in the development of next-generation PCVs and might guide policy makers in the selection of future pneumococcal vaccines.

FUNDING

Foundation for Medical Research; Pfizer, BioMérieux, Sanofi for the Regional Observatory of Pneumococci.