RESUMEN

We measured anti-pneumococcal serotype 19A vaccine-induced antibodies in 160 children (611 sera) after introduction of 13-valent pneumococcal conjugate vaccine and naturally-induced antibodies in 59 children (185 sera) after colonization and acute otitis media (AOM) episodes caused by strains expressing serotype 19A. Correlate of protection (COP) models were constructed using results from multiple prospectively-collected observations in individual children. Generalized estimating equations followed by logistic-regression was used. The COP derived from vaccine-induced antibody levels for prevention of colonization was 5 µg/mL and for AOM was 2.3 µg/mL. A COP for naturally-induced antibody levels for prevention of colonization or AOM could not be derived because an age gradient was not observed. Combining natural- and vaccine-induced antibody levels did not provide biologically plausible COP estimates. We conclude derivation of a COP for prevention of colonization and AOM using individual multi-point child data for pneumococcal serotype 19A can be estimated when an age-gradient is observed.

RESUMEN

Streptococcus pneumoniae serotype 19A is a highly diverse, often antimicrobial-resistant Gram-positive bacterium which can cause invasive pneumococcal disease (IPD). In 2021, public health authorities in the Canadian province of Québec observed an increase of serotype 19A IPD in children <5 years. The purpose of this study was to determine the clonal composition of serotype 19A isolates collected from this age group in Québec, from 2016 to 2021. Forty-one and 37 IPD isolates from children <5 years from Québec and the remainder of Canada, respectively, were sequenced using the Illumina NextSeq platform. Phylogenetic analysis using SNVPhyl identified three clusters, corresponding to three common clones of serotype 19A: CC199, CC320 and ST695. CC199, predominantly represented by ST416, accounted for similar proportions of serotype 19A isolates collected from children in Québec (19.5 %) and other Canadian jurisdictions (OCJs, 21.6 %), with significant presence of ermB (62.5 % and 60 % of ST416 isolates, respectively). CC320 was more commonly identified from OCJs in comparison to Québec (18.9 % vs. 7.3 %, respectively), but were highly antimicrobial-resistant regardless of region. ST695 was the most common clone of serotype 19A collected in Québec from children <5 years, representing 65.9 % of isolates collected over the study period (40.5 % of isolates collected in OCJs). Phylogenetic analysis identified geographical differences in ST695 across Canada; including a large clade specific to Québec (with both susceptible and macrolide-resistant [ermB] subclades), and a separate macrolide-resistant (mefA) clade associated with OCJs. The Québec-specific ermB-ST695 clone represented 48.1 % of ST695 collected from the province. Continued genomic surveillance of S. pneumoniae serotype 19A is required to: i) track the prevalence and clonal composition of serotype 19A in Québec in future years; ii) characterize the clonal distribution of serotype 19A in adult populations; and iii) monitor whether the currently geographically restricted ermB-ST695 clone observed in Québec expands to OCJs.

RESUMEN

INTRODUCTION: The introduction of pneumococcal conjugate vaccines (PCV) into the national immunization programs (NIPs) has significantly reduced the number of pneumococcal infections. However, infections caused by isolates of non-vaccine serotypes (NVT) started spreading shortly thereafter and strains of NVT 19A have become the main cause of invasive pneumococcal disease burden worldwide. The aim of the study was to characterize serotype 19A invasive pneumococci of GPSC1/CC320 circulating in Poland before the introduction of PCV into the Polish NIP in 2017 and to compare them to isolates from other countries where PCVs were implemented much earlier than in Poland. METHODS: All the GPSC1/CC320 isolates were analyzed by serotyping, susceptibility testing, and whole genome sequencing followed by analyses of resistome, virulome, and core genome multilocus sequence typing (cgMLST), including comparative analysis with isolates with publicly accessible genomic sequences (PubMLST). RESULTS: During continuous surveillance the NRCBM collected 4237 invasive Streptococcus pneumoniae isolates between 1997 and 2016, including 200 isolates (4.7%) of serotype 19A. The most prevalent among 19A pneumococci were highly resistant representatives of Global Pneumococcal Sequence Cluster 1/Clonal Complex 320, GPSC1/CC320 (n = 97, 48.5%). Isolates of GPSC1/CC320 belonged to three sequence types (STs): ST320 (75.2%) ST4768 (23.7%), and ST15047 (1.0%), which all represented the 19A-III cps subtype and had complete loci for both PI-1 and PI-2 pili types. On the basis of the cgMLST analysis the majority of Polish GPSC1/CC320 isolates formed a group clearly distinct from pneumococci of this clone observed in other countries. CONCLUSION: Before introduction of PCV in the Polish NIP we noticed an unexpected increase of serotype 19A in invasive pneumococcal infections, with the most common being representatives of highly drug-resistant GPSC1/CC320 clone, rarely identified in Europe both before and even after PCV introduction.

RESUMEN

PURPOSE: This study aimed to evaluate and compare the presence of genes related to surface proteins between isolates of Streptococcus pneumoniae from healthy carriers (HC) and invasive pneumococcal disease (IPD) with a particular focus on serotype 19A. METHODS: The presence of these genes was identified by real-time PCR. Subsequently, we employed the Galleria mellonella larval infection model to study their effect on pathogenicity in vivo. RESULTS: The percentage of selected virulence genes was similar between the HC and IPD groups (p > 0.05), and the genes lytA, nanB, pavA, pcpA, phtA, phtB, phtE, rrgA, and sipA were all present in both groups. However, the virulence profile of the isolates differed individually between HC and IPD groups. The highest lethality in G. mellonella was for IPD isolates (p < 0.01), even when the virulence profile was the same as compared to the HC isolates or when the nanA, pspA, pspA-fam1, and pspC genes were not present. CONCLUSIONS: The occurrence of the investigated virulence genes was similar between HC and IPD S. pneumoniae serotype 19A groups. However, the IPD isolates showed a higher lethality in the alternative G. mellonella model than the HC isolates, regardless of the virulence gene composition, indicating that other virulence factors may play a decisive role in virulence. Currently, this is the first report using the in vivo G. mellonella model to study the virulence of clinical isolates of S. pneumoniae.

Asunto(s)

RESUMEN

Biofilm formation by Streptococcus pneumoniae is associated with colonization of the upper respiratory tract, including the carrier state, and with chronic respiratory infections in patients suffering from chronic obstructive pulmonary disease (COPD). The use of antibiotics alone to treat recalcitrant infections caused by biofilms is insufficient in many cases, requiring novel strategies based on a combination of antibiotics with other agents, including antibodies, enzybiotics, and antioxidants. In this work, we demonstrate that the third-generation oral cephalosporin cefditoren (CDN) and the antioxidant N-acetyl-l-cysteine (NAC) are synergistic against pneumococcal biofilms. Additionally, the combination of CDN and NAC resulted in the inhibition of bacterial growth (planktonic and biofilm cells) and destruction of the biofilm biomass. This marked antimicrobial effect was also observed in terms of viability in both inhibition (prevention) and disaggregation (treatment) assays. Moreover, the use of CDN and NAC reduced bacterial adhesion to human lung epithelial cells, confirming that this strategy of combining these two compounds is effective against resistant pneumococcal strains colonizing the lung epithelium. Finally, administration of CDN and NAC in mice suffering acute pneumococcal pneumonia caused by a multidrug-resistant strain was effective in clearing the bacteria from the respiratory tract in comparison to treatment with either compound alone. Overall, these results demonstrate that the combination of oral cephalosporins and antioxidants, such as CDN and NAC, respectively, is a promising strategy against respiratory biofilms caused by S. pneumoniae. IMPORTANCE Streptococcus pneumoniae is one of the deadliest bacterial pathogens, accounting for up to 2 million deaths annually prior to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Vaccines have decreased the burden of diseases produced by S. pneumoniae, but the rise of antibiotic-resistant strains and nonvaccine serotypes is worrisome. Pneumococcal biofilms are associated with chronic respiratory infections, and treatment is challenging, making the search for new antibiofilm therapies a priority as biofilms become resistant to traditional antibiotics. In this work, we used the combination of an antibiotic (CDN) and an antioxidant (NAC) to treat the pneumococcal biofilms of relevant clinical isolates. We demonstrated a synergy between CDN and NAC that inhibited and treated pneumococcal biofilms, impaired pneumococcal adherence to the lung epithelium, and treated pneumonia in a mouse pneumonia model. We propose the widely used cephalosporin CDN and the repurposed drug NAC as a new antibiofilm therapy against S. pneumoniae biofilms, including those formed by antibiotic-resistant clinical isolates.

Asunto(s)

RESUMEN

After switching from 13-valent to 10-valent pneumococcal conjugate vaccine (PCV10) (2015-2016) for children in Belgium, we observed rapid reemergence of serotype 19A invasive pneumococcal disease (IPD). Whole-genome sequencing of 166 serotype 19A IPD isolates from children (n = 54) and older adults (n = 56) and carriage isolates from healthy children (n = 56) collected after the vaccine switch (2017-2018) showed 24 sequence types (STs). ST416 (global pneumococcal sequence cluster [GPSC] 4) and ST994 (GPSC146) accounted for 75.9% of IPD strains from children and 65.7% of IPD (children and older adults) and carriage isolates in the PCV10 period (2017-2018). These STs differed from predominant 19A IPD STs after introduction of PCV7 (2011) in Belgium (ST193 [GPSC11] and ST276 [GPSC10]), which indicates that prediction of emerging strains cannot be based solely on historical emerging strains. Despite their susceptible antimicrobial drug profiles, these clones spread in carriage and IPD during PCV10 use.

Asunto(s)

RESUMEN

AIM: To present the results of whole genome sequencing (WGS) analysis of Streptococcus pneumoniae serotype 19A and to compare them with the respective data from Europe. The vaccine serotype 19A is widely distributed in the Czech Republic. MATERIAL AND METHODS: WGS was used in this study as the most powerful available method for detailed characterization of S. pneumoniae. Nineteen Czech isolates of S. pneumoniae 19A were analysed and compared with 415 European isolates included in the PubMLST database. RESULTS: S. pneumoniae serotype 19A causes all types of pathogen - host interaction, from carriage to noninvasive and invasive pneumococcal disease (IPD). In 2010 - 2019, 3872 cases of IPD were reported within the surveillance programme in the Czech Republic, with 323 of these caused by serotype 19A. WGS data of the Czech serotype 19A isolates show a numerous and genetically related subpopulation of three sequencing types: ST-199, ST-416, and ST-3017. Within this subpopulation, the largest is the cluster of nine ST-199 isolates. High relatedness of ST-199 isolates is also confirmed by the fact that all but one isolate, 117/2019 (novel rST- -137805), share the same ribosome sequencing profile - rST-11365. Outside the above-mentioned subpopulation, there are only four isolates that form three separate genetic lines of serotype 19A. A highly similar situation is observed across European countries, where about half of all serotype 19A isolates form a genetically closely related subpopulation (ST-199, ST-416, ST-450, ST-667, ST-3017, and ST-10360) while isolates which are not part of this subpopulation represent a large number of unrelated genetic lines. CONCLUSIONS: The study has shown a mostly homogeneous population of S. pneumoniae serotype 19A to circulate in the post-vaccination era in both the Czech Republic and Europe, with some unrelated isolates located outside this population.

Asunto(s)

RESUMEN

Streptococcus pneumoniae serotype 19A prevalence has increased after the implementation of the PCV7 and PCV10 vaccines. In this study, we have provided, with high accuracy, the genetic diversity of the 19A serotype in a cohort of Dutch invasive pneumococcal disease patients and asymptomatic carriers obtained in the period from 2004 to 2016. The whole genomes of the 338 pneumococcal isolates in this cohort were sequenced and their capsule (cps) loci compared to examine their diversity and determine the impact on the production of capsular polysaccharide (CPS) sugar precursors and CPS shedding. We discovered 79 types with a unique cps locus sequence. Most variation was observed in the rmlB and rmlD genes of the TDP-Rha synthesis pathway and in the wzg gene, which is of unknown function. Interestingly, gene variation in the cps locus was conserved in multiple alleles. Using RmlB and RmlD protein models, we predict that enzymatic function is not affected by the single-nucleotide polymorphisms as identified. To determine if RmlB and RmlD function was affected, we analyzed nucleotide sugar levels using ultrahigh-performance liquid chromatography-mass spectrometry (UHPLC-MS). CPS precursors differed between 19A cps locus subtypes, including TDP-Rha, but no clear correlation was observed. Also, significant differences in multiple nucleotide sugar levels were observed between phylogenetically branched groups. Because of indications of a role for Wzg in capsule shedding, we analyzed if this was affected. No clear indication of a direct role in shedding was found. We thus describe genotypic variety in rmlB, rmlD, and wzg in serotype 19A in the Netherlands, for which we have not discovered an associated phenotype.

Asunto(s)

RESUMEN

BACKGROUND: Streptococcus pneumoniae serotype 19A remains a significant cause of invasive pneumococcal disease (IPD) in Ireland despite the successful introduction of a 13-valent pneumococcal conjugate vaccine (PCV13) in 2010 which reduced the overall incidence of IPD in children. METHODS: Invasive Streptococcus pneumoniae serotype 19A isolates from the Irish reference laboratory between 2007-08 and 2017-18 were analysed using whole genome sequencing (WGS) to investigate the persistence of this vaccine-preventable serotype. We compared the entire national 19A collection to other international collections using a standardised nomenclature of Global Pneumococcal Sequencing Clusters (GPSC). RESULTS: Expansion of GPSCs and clonal complexes (CCs) may have been associated with vaccine introduction and antimicrobial prescribing policies. A sub-clade of GPSC1-CC320 (n = 25) unique to Ireland, included five of the ten vaccine failures/breakthrough cases identified (p = 0.0086). This sub-clade was not observed in a global GPSC1-CC320 collection. All isolates within the sub-clade (n = 25) contained a galE gene variant rarely observed in a global pneumococcal collection (n = 37/13454, p < 0.001) nor within GPSC1-CC320 (n = 19/227) (p < 0.001). The sub-clade was estimated to have emerged at the start of the PCV-vaccine era (ancestral origin 2000, range 1995-2004) and expanded in Ireland, with most isolated after PCV13 introduction (n = 24/25). CONCLUSIONS: The identification of a sub-clade/variant of serotype 19A highlights the benefit of using WGS to analyse genotypes associated with persistence of a preventable serotype of S. pneumoniae. Particularly as this sub-clade identified was more likely to be associated with IPD in vaccinated children than other 19A genotypes. It is possible that changes to the galE gene, which is involved in capsule production but outside of the capsular polysaccharide biosynthesis locus, may affect bacterial persistence within the population. Discrete changes associated with vaccine-serotype persistence should be further investigated and may inform vaccine strategies.

Asunto(s)

RESUMEN

BACKGROUND: In several countries, introduction of the pneumococcal conjugate vaccine (PCV) has led to a decline in antimicrobial-resistant pneumococcal disease but has also resulted in a concomitant increase in antimicrobial-resistant, non-vaccine serotypes of Streptococcus pneumoniae. We sought to determine the magnitude of penicillin and macrolide resistance among pneumococcal serotypes and the mechanisms of macrolide resistance in Ethiopia, 5 years after the introduction of PCV10 in the country. METHODS: Susceptibility to penicillin and erythromycin of 119 pneumococcal isolates collected from pediatric patients aged 0-15 years in Addis Ababa, Ethiopia, was tested using disc diffusion, and minimum inhibitory concentration (MIC) was also determined by Etest. Pneumococcal serotypes were determined by sequencing the cpsB gene and using Quellung reaction. Polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism analysis were used to detect and differentiate the macrolide resistance genes erm(B), mef(A), and mef(B). RESULTS: Among the 119 isolates, 2.5% (3/119) were resistant to penicillin, while 58% (69/119) were intermediate. Resistance to erythromycin was observed in 33.6% (40/119) of the isolates with the highest level of resistance among isolates from middle ear discharge, i.e., 53.3% (8/15). Half (19/40) of the erythromycin resistant isolates were serotype 19A and among serotype 19A isolates, the majority i.e., 54.3% (19/35) were resistant to erythromycin. The most common macrolide resistance determinant was mef(E) with a prevalence of 50% (20/40). CONCLUSION: Five years after introduction of PCV10 in Ethiopia, we observed that the prevalence of penicillin-resistant S. pneumoniae was low. However, there was a high level of macrolide resistance which was mostly in serotype 19A, and the resistance was mainly mediated by efflux pumps. Introduction of PCV13 (which covers serotype 19A) would significantly improve coverage of the macrolide-resistant serotypes. Continued surveillance of pneumococcal serotype distribution and their antibiotic resistance pattern in Ethiopia is warranted.

RESUMEN

Since the introduction of the pneumococcal conjugate vaccine, an increase in the incidence of Streptococcus pneumoniae serotype 19A and sequence type 320 (19A-ST320) isolates have been observed worldwide including in South Korea. We conducted a genome-wide analysis to investigate the temporal genetic changes in 26 penicillin-non-susceptible 19A-ST320 pneumococcal isolates from a hospital in South Korea over a period of 17 years (1999; 2004 to 2015). Although the strains were isolated from a single hospital and showed the same genotype and serotype, a whole-genome sequencing (WGS) analysis revealed that the S. pneumoniae isolates showed more extensive genetic variations compared with a reference isolate obtained in 1999. A phylogenetic analysis based on single nucleotide polymorphisms (SNPs) showed that the pneumococcal isolates from South Korea were not grouped together into limited clusters among the 19A-ST320 isolates from several continents. It was predicted that recombination events occurred in 11 isolates; larger numbers of SNPs were found within recombination blocks compared with point mutations identified in five isolates. WGS data indicated that S. pneumoniae 19A-ST320 isolates might have been introduced into South Korea from various other countries. In addition, it was revealed that recombination may play a great role in the evolution of pneumococci even in very limited places and periods.

RESUMEN

INTRODUCTION: Streptococcus pneumoniae is a major cause of morbidity and mortality, especially amongst young children and the elderly. Childhood implementation of pneumococcal conjugate vaccines (PCVs) significantly reduced the incidence of invasive pneumococcal disease (IPD), while several nonvaccine serotypes remained substantial. Although there is evidence of the impact of higher-valent PCVs on serotype 19A, 19A IPD burden and antibiotic resistance remain a major concern post-vaccination. AREAS COVERED: We performed a systematic literature review to analyze the frequency and clonal distribution of serotype 19A isolates in the pre- and post-PCV era worldwide providing a scientific background on the factors that influence multidrug resistance in pneumococcal isolates. EXPERT COMMENTARY: Serotype 19A IPD incidence increased in all regions following the introduction of the 7-valent PCV. The higher-valent PCVs have reduced the rates of 19A IPD isolates, but several circulating strains with diverse antibiotic resistance prevailed. Heterogeneous clonal distribution in serotype 19A was observed within countries and regions, irrespective of higher-valent PCV used. An increase of 19A isolates from pre- to post-vaccination periods were associated with frequently occurring serotype switching events and with the prevalence of multidrug resistant strains. Rational antibiotic policies must be implemented to control the emergence of resistance.Plain Language SummaryWhat is the context?Streptococcus pneumoniae is a major cause of pneumococcal diseases especially amongst young children and the elderly. Vaccination with pneumococcal conjugate vaccines has significantly reduced the incidence of invasive pneumococcal disease worldwide. However, the invasive pneumococcal disease remains an important health problem due to the increase of nonvaccine serotypes. Serotype 19A is predominant in many countries worldwide. Factors contributing to its prevalence include serotype replacement, the emergence of clones with multidrug resistance due to antibiotic overuse, and potential bacteria adaptation in response to the vaccine.What is new?We performed a systematic literature review to 1) analyze the incidence and clonal distribution of serotype 19A isolates pre- and post-vaccination worldwide, and to collect data evaluating antimicrobial resistance patterns displayed by the clones of serotype 19A. We found that 1) clonal distribution in serotype 19A was heterogeneous within countries and regions, irrespective of the vaccine used; 2) the diversity of 19A isolates increased after vaccination. It was associated with frequent serotype switching events and with the prevalence of multidrug resistant strains.What is the impact?Implementation of policies to educate on sustainable antibiotic use and infectious prevention measures may help control the emergence of antibiotic resistance. High-quality active surveillance and future molecular epidemiology studies are needed to understand rapid genetic changes.

Asunto(s)

RESUMEN

Streptococcus pneumoniae (S. pneumoniae) colonizes asymptomatically the human nasopharynx. This pathogen is responsible for sinusitis, otitis media, pneumonia, bacteremia and meningitis. We report the case of a 35-year-old female patient who developed a surgical wound infection by a multi drug resistant S. pneumoniae serotype 19A after a total coloprotectomy. This first found in Morocco shows the implication of multidrug resistant S. pneumoniae in surgical wound infections.

Asunto(s)

RESUMEN

Community-acquired pneumonia (CAP) is a leading cause of childhood mortality and morbidity worldwide. PCV-13 has implemented incidence of CAP undoubtedly in a very good way but continuous surveillance for vaccine failures is still very important for future vaccination programs. To support this opinion we report seven children (age of the seven patients ranged between 10 months and 5 y, 10 months old patients were vaccinated 3 times with PCV13 whereas others were fully vaccinated as 3 + 1) infected with Streptococcus pneumoniae Serotype 19A in last 4 y (2015-2018).

Asunto(s)

RESUMEN

The routine use of pneumococcal conjugated vaccines (PCVs) in childhood has significantly reduced the frequency of invasive pneumococcal diseases (IPDs). Serotype replacement has occurred, resulting in an increase in nonvaccine serotypes. Despite this changing profile, both invasive and noninvasive cases continue to be seen with strains within the scope of PCV coverage. Although older children with comorbid disease are described as a risky group for vaccine insufficiency, vaccine failure patterns should be described in detail.

Asunto(s)

RESUMEN

Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide, especially among children and the elderly. S. pneumoniae serotype 19A has emerged as a major cause of invasive disease in many countries, regardless of whether pneumococcal conjugate vaccines are used. The aim of this study was molecular characterization of invasive S. pneumoniae serotype 19A isolates recovered between 2000 and 2015 from 13 National Laboratories through the laboratory-based surveillance of invasive S. pneumoniae program SIREVA II in Latin American countries. The isolates were submitted with antimicrobial susceptibility tests and were genotyped by a combination of pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Of the 185 isolates assayed, notable rates of resistance to penicillin (MIC ≥ 0.125 µg/mL; 68.6%), tetracycline (63.7%), trimethoprim-sulfamethoxazole (63.2%), and erythromycin (43.2%) were observed, while 44.3% of isolates were multidrug resistant. The most frequently observed sequence types (ST) were ST320 (32.4%), ST199 (14.1%), ST172 (10.8%) and ST5204 (7.1%). The distribution of STs indicated regional differences in the epidemiology of the clonal groups. The present study showed a diverse genetic background of the pneumococcal population in Latin American countries. Continuous surveillance of the pneumococcal serotype 19A population in the region will be necessary to obtain information about geographical differences and changes in the spread and the establishment of particular clones.

Asunto(s)

RESUMEN

Introduction: With the use of pneumococcal conjugate vaccines(PCV), the behavior of invasive pneumococcal disease(IPD) has changed relative to serotype distribution. The introduction of these vaccines in national immunization programs has reduced the incidence of IPD, with a marked decrease in the circulation of the serotypes included in the vaccine used in each country. However, the subsequent emergence of other serotypes not included in the vaccine, such 19A in case of PCV7 and PCV10, has been documented. Materials and methods: This was case series study (2008-2017) in pediatric patients admitted to 10 hospitals in Bogota who were diagnosed with IPD. It was conducted during the transitional period of implementing the PCV10 vaccine in Colombia in 2012. Cases of bacteremic pneumococcal pneumonia, meningitis, primary bacteremia and osteoarticular infection were included. A descriptive analysis of the demographic, clinical and laboratory variables of patients with IPD by Spn19A, its trend over time, profiles of antimicrobial susceptibility and clinical outcomes was performed. Results: There were 463 cases of IPD, 315(68%) with known serotypes. The prevalence of IPD by Spn19A was 17.7%(56 cases), tending to increase over time. During 2008-2011, the prevalence was 4.4%, and during 2014-2017, it was 32.4%, The most frequent diagnosis was pneumonia(80.4%). In nonmeningeal isolates, 39.6% were not susceptible to penicillin. An increase in the resistance was observed over time. Conclusion: Spn19A is a prevalent cause of IPD in the pediatric population of the analyzed cohort, with an increasing trend of this serotype during the surveillance period after the introduction of PCV10, being the most common serotype identified in recent years.

Asunto(s)

RESUMEN

Introduction: By preventing nasopharyngeal carriage acquisition among vaccinated persons, and thus reducing transmission, pneumococcal conjugate vaccines (PCVs) provide protection against pneumococcal vaccine serotypes among unvaccinated individuals. This systematic review assessed PCVs containing serotype 19A or cross-reactive 19F for 19A carriage effects.Areas covered: Peer-reviewed literature was searched for manuscripts published between 1/1/2000 and 06/18/2018 assessing the impact of PCV on 19A carriage.Expert opinion: Fifty-five, 12, and 32 articles were identified for PCV7, PCV10, and PCV13, respectively. In two of four PCV7 randomized controlled trials (RCTs), 19A carriage was significantly higher in PCV7-vaccinated vs control subjects; in two of two PCV10 RCTs, there was no significant difference in 19A carriage and acquisition between PCV10-vaccinated (2 + 1 schedule) vs control subjects, apart from one timepoint (3 + 1 schedule); and one of one RCTs of PCV13 showed significant decreases in 19A carriage and acquisition in PCV13- vs PCV7-vaccinated (3 + 1 schedule) children. These findings were consistent with observational studies in which an increase or no change in 19A carriage was observed in 91% and 67% of PCV7 and PCV10 studies, respectively, whereas 87% of PCV13 studies documented a decrease. Countries in which serotype 19A transmission is substantial should consider the use of vaccines containing serotype 19A.

Asunto(s)

RESUMEN

Pneumococcal conjugate vaccines (PCV) have been widely used in high-income countries for more than a decade, resulting in a dramatic reduction in pneumococcal disease caused by vaccine serotypes. PCV has been included in Turkey's National Immunization Programme since 2009 with PCV7 and continued with PCV13 from 2011. We presented a three-month-old infant who developed mastoiditis secondary to S. pneumoniae serotype 19A after acute otitis media.

Asunto(s)

RESUMEN

Introduction: Streptococcus pneumoniae is a leading cause of morbidity and mortality worldwide. Widespread infant vaccination with pneumococcal conjugate vaccines (PCVs) substantially reduced vaccine-serotype pneumococcal disease by direct protection of immunized children and indirect protection of the community via decreased nasopharyngeal carriage and transmission. Essential to grasping the public health implications of pediatric PCV immunization is an understanding of how PCV formulations impact carriage. Areas covered: Using clinical evidence, this review examines how the immune response to PCVs is associated with subsequent nasopharyngeal carriage reduction in vaccinated infants and toddlers. By combining direct and indirect protection, carriage reduction results in a reduced spread of vaccine serotypes, and eventually, a decrease in vaccine serotype disease incidence in community members of all ages. Expert opinion: The current review presents some of the aspects that influence the overall impact of PCVs on vaccine-serotype carriage, and thus, spread. The link between reduction of vaccine-serotype carriage and the eventual reduction of vaccine-serotype disease in the wider community is described by comparing data from current PCVs, specifically with respect to their ability to reduce carriage of some cross-reacting serotypes (i.e. 6A versus 6B and 19A versus 19F).

Asunto(s)