Changes in nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis among healthy children attending a day-care centre before and after official financial support for the 7-valent pneumococcal conjugate vaccine and H. influenzae type b vaccine in Japan

Nasopharyngeal carriage of Haemophilus influenzae among adults with co-morbidities

After the widespread use of Haemophilus influenzae type b (Hib) vaccine, H. influenzae invasive disease is now commonly due to non-encapsulated (NTHi), affecting mostly the youngest and the elderly. The objective of this study was to investigate H. influenzae nasopharyngeal carriage rate in adults with co-morbidities and possible associated risk factors.

METHODS

Patients aged >50 years with co-morbidities attending medical centres were examined. A nasopharyngeal swab was analysed for H. influenzae presence by cultural and molecular methods (RT-PCR). Univariable and multivariable analysis of risk factors for H. influenzae carriage were performed. Serotype of isolates was determined by PCR capsular genotyping. Minimum inhibitory concentration (MIC) was determined by MIC gradient test and β-lactamase production was detected by the nitrocephin test. Genotyping was performed by Multilocus sequence typing (MLST). Phylogenetic relationships among carriage and invasive NTHi strains were assessed.

RESULTS

Among 248 enrolled patients (median age: 73 years), the carriage rate was 5.6% and 10.5% by cultural method or RT-PCR, respectively. Colonization with H. influenzae was significantly associated with the presence of acute respiratory symptoms (adjusted OR = 12.16, 95% CI: 3.05-48.58, p < 0.001). All colonizing isolates were NTHi. Three isolates (3/14, 21.4%) were resistant to ampicillin and beta-lactamase positive. MLST revealed a high degree of genetic diversity, with 11 different STs from 14 isolates. Eight out of the 11 (72.7%) STs were shared among carriage and invasive isolates.

CONCLUSIONS

Adults ≥50 years old with co-morbidities are occasionally colonized by H. influenzae, even if the presence of co-morbidities is not a risk factor for colonization. The presence of acute respiratory symptoms is the only factor associated with H. influenzae colonization. Colonizing H. influenzae are all NTHi. Colonizing H. influenzae often belong to the same STs of invasive disease isolates.

Study of normal flora in the pharynx of healthy children

To improve our current understanding of normal flora in children, we investigated bacterial isolates from pharynx and nasopharynx of 173 and 233 healthy children, respectively. The bacterial isolation rates were compared among three age groups: infants (<1 year), toddlers (1-5 years), and school-age children (6-15 years). Gram-positive cocci (GPC) were the predominant bacteria in the pharynx (Streptococcus mitis/oralis, 87.3%; Streptococcus salivarius, 54.3%; Rothia mucilaginosa, 41.6%; Staphylococcus aureus, 39.3%). Among infants, Streptococcus salivarius and Neisseria subflava, which are related to the development of teeth, were significantly lower than in the other age groups (p<0.0001, S. salivarius; p<0.01, N. subflava). Gram-negative rods (GNR) predominated the nasopharynx (Moraxella catarrhalis, 32.1%; and Moraxella nonliquefaciens, 28.3%) except for Corynebacterium pseudodiphtheriticum (44.2%) of gram-positive rods. Among toddlers, Moraxella catarrhalis and Streptococcus pneumoniae, which are the most common pathogens in acute otitis media, were significantly higher than in the infant group (p<0.05 for both). Among bacterial species implicated in pediatric respiratory infection, Streptococcus pyogenes was isolated in 3.5% of pharyngeal samples. S. pneumoniae and Haemophilus influenzae were isolated in 22.3% and 17.2% of nasopharyngeal samples, respectively. In conclusion, normal flora of the respiratory tract differs not only by sampling site but also by age group.

Clinical characteristics of community-acquired pneumonia due to Moraxella catarrhalis in adults: a retrospective single-centre study

Background

Although Moraxella catarrhalis (M. catarrhalis) is a common cause of community-acquired pneumonia (CAP), studies investigating clinical manifestations of CAP due to M. catarrhalis (MC-CAP) in adults are limited. Since S. pneumoniae is the leading cause of CAP globally, it is important to distinguish between MC-CAP and CAP due to S. pneumoniae (SP-CAP) in clinical practice. However, no past study compared clinical characteristics of MC-CAP and SP-CAP by statistical analysis. We aimed to clarify the clinical characteristics of MC-CAP by comparing those of SP-CAP, as well as the utility of sputum Gram staining.

Methods

This retrospective study screened CAP patients aged over 20 years visiting or admitted to Okinawa Miyako Hospital between May 2013 and April 2018. Among these, we included patients whom either M. catarrhalis alone or S. pneumoniae alone was isolated from their sputum by bacterial cultures.

Results

We identified 134 MC-CAP and 130 SP-CAP patients. Although seasonality was not observed in SP-CAP, almost half of MC-CAP patients were admitted in the winter. Compared to those with SP-CAP, MC-CAP patients were older (p < 0.01) and more likely to have underlying pulmonary diseases such as asthma and bronchiectasis (p < 0.01). Approximately half of asthmatic MC-CAP and SP-CAP patients had asthma attacks. Although winter is an influenza season in Japan, co-infection with influenza virus was less common in MC-CAP compared to SP-CAP patients (3% vs. 15%, p < 0.01). Bronchopneumonia patterns on X-ray, as well as bronchial wall thickening, bilateral distribution, and segmental pattern on CT were more common in MC-CAP patients than in SP-CAP patients (p < 0.01). Sputum Gram stain was highly useful method for the diagnosis in both MC-CAP and SP-CAP (78.4% vs. 89.2%), and penicillins were most frequently chosen as an initial treatment for both pneumonias.

Conclusions

This is the first study to show that MC-CAP occurred in older people compared to SP-CAP, influenza virus co-infection was less common in MC-CAP than SP-CAP, and that MC-CAP frequently caused asthma attacks. Gram stain contributed for the appropriate treatment, resulting in conserving broad-spectrum antibiotics such as cephalosporins and fluoroquinolones in both MC-CAP and SP-CAP patients.

The prevalence and antimicrobial susceptibility of Streptococcus pneumoniae isolated from patients at Jikei University Hospitals after the implementation of the pneumococcal vaccination program in Japan

Studies have shown that pneumococcal vaccination reduces the incidence of Streptococcus pneumoniae infections but does not change the prevalence of S. pneumoniae nasopharyngeal colonization. To comprehensively and longitudinally assess the epidemiology of S. pneumoniae after the introduction of pneumococcal vaccination, we monitored the prevalence and antimicrobial susceptibility of S. pneumoniae, irrespective of its serotypes or pathogenicity, by analyzing specimens collected from a large number of patients at Jikei University Hospitals from 2009 to 2017. A total of 5763 S. pneumoniae isolates were identified out of 375,435 specimens from various sources of patients in different age groups. The prevalence of S. pneumoniae isolated only from patients <5 years old was significantly reduced with the widespread use of pneumococcal vaccines, although this reduction differed by areas where patients resided. The incidence of pneumococcal infections, including bacteremia and otitis media, clearly decreased among patients <5 years old after the introduction of pneumococcal vaccination, while the prevalence of S. pneumoniae isolated from blood specimens of patients 15-64 years old increased, suggesting the involvement of non-vaccine serotypes in the incidence of invasive pneumococcal infections. The antimicrobial susceptibility of S. pneumoniae improved after the introduction of pneumococcal vaccination. Our results show that pneumococcal vaccination has a suppressive effect on the prevalence of S. pneumoniae and the incidence of pneumococcal infections, at least for children <5 years old, in association with an improvement in the antimicrobial susceptibility of S. pneumoniae. However, further measures will be needed to control invasive pneumococcal infections caused by non-vaccine serotypes.

Co-carriage of Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis among three different age categories of children in Hungary

Background

The nasopharynx can from time to time accommodate otherwise pathogenic bacteria. This phenomenon is called asymptomatic carriage. However, in case of decreased immunity, viral infection or any other enhancing factors, severe disease can develop. Our aim in this study was to survey the nasal carriage rates of four important respiratory pathogens in three different age groups of children attending nurseries, day-care centres and primary schools. This is the first study from Hungary about the asymptomatic carriage of H. influenzae and M. catarrhalis.

Methods

Altogether 580 asymptomatic children were screened in three Hungarian cities. Samples were collected from both nostrils with cotton swabs. The identification was based on both colony morphology and species-specific PCRs. Serotyping was performed for S. pneumoniae, H. influenzae and M. catarrhalis. Antibiotic susceptibility was determined with agar dilution, according to the EUCAST guidelines. Clonality was examined by PFGE.

Results and conclusions

Whereas the carriage rates of S. pneumoniae, H. influenzae and M. catarrhalis clearly decreased with age, that of S. aureus showed an opposite tendency. Multiple carriage was least prevalent if S. aureus was one of the participants. The negative association between this bacterium and the others was statistically significant. For pneumococcus, the overall carriage rate was lower compared to earlier years, and PCV13 serotypes were present in only 6.2% of the children. The majority of H. influenzae isolates was non-typeable and no type b was detected; serotype A was dominant among M. catarrhalis. All four bacteria were more sensitive to antibiotics compared to clinical isolates. No MRSAs were detected, but we found three mupirocin resistant strains. The positive effect of Hib- and PCV-vaccination is undoubted. Continued surveillance of these pathogens is required.

The pharyngeal carriage of Haemophilus influenzae among healthy population in China: a systematic review and meta-analysis

BACKGROUND

A nationwide investigation on the carriage proportion of H. influenzae among healthy populations is lacking in China. The purpose of the study was to review the prevalence of pharyngeal carriage of H. influenzae among healthy populations in China, and explore its influencing factors. The serotypes distribution of H. influenzae was also analyzed.

METHODS

A systematic search was conducted with key words "Haemophilus influenzae", "Carriage", and "China" or "Chinese" from inception to March 2018. After careful screening, the data of included articles were extracted with a pre-designed excel form. Then, the pooled carriage proportion of H. influenzae was calculated using the random effect model.

RESULTS

A total of 42 studies with 17,388 participants were included. The overall pooled carriage proportion of H. influenzae was 0.17 (95% CI: 0.13-0.21), and the carriage proportion largely varied by province. Subgroup analysis indicated that the pooled carriage proportion was 0.17 (0.13-0.21) for children, and 0.14 (0.7-0.23) for adults. There were no statistically significant heterogeneity between subgroups by age (p = 0.65), sex (p = 0.88), and season (p = 0.10). The pooled carriage proportion of Hib was 0.01 (0-0.02), while the carriage proportion of NTHi was 0.22 (0.13-0.31).

CONCLUSION

In China, the carriage proportion of H. influenzae among healthy population was low, but it largely varied by provinces.

The complexity of serotype replacement of pneumococci

Pneumococci respond extremely rapidly to the vaccine pressure created by the conjugate vaccines (PCVs). Vaccine serotypes are disappearing, meanwhile new, often previously very rare types are emerging, and it is difficult to establish what makes certain serotypes more successful in replacement. The situation is very complex: every serotype has different antibiotic sensitivity or invasive capacity. However, despite this dynamic serotype rearrangement, the overall pneumococcal carriage rate remains quite stable, suggesting that these bacterial species can be considered as a commensal colonizer.

A nationwide population-based surveillance of invasive Haemophilus influenzae diseases in children after the introduction of the Haemophilus influenzae type b vaccine in Japan

BACKGROUND

Haemophilus influenzae type b (Hib) vaccine was introduced as a voluntary vaccine in December 2008 and was included in the national routine immunization program in April 2013 in Japan. Currently, no nationwide data are available to evaluate the effectiveness of Hib vaccine in Japan.

METHODS

To evaluate the effectiveness of Hib vaccine in Japan, nationwide active population-based surveillance of culture-proven invasive infections caused by H. influenzae in children was performed in 2008-2017 in 10 prefectures in Japan (covering approximately 23% of the total Japanese population). Clinical data were recorded on a standardized case report form. Capsular type and antimicrobial susceptibility of the H. influenzae isolates were examined. The incidence rate ratio (IRR) and its confidence interval (CI) were calculated to compare data from 5 years before and that from after the introduction of the national routine Hib vaccine immunization program.

RESULTS

During the 10-year study period, 566 invasive H. influenzae disease cases including 336 meningitis cases were identified. The average number of invasive H. influenzae disease cases among children <5 years of age during 2013-2017 decreased by 93% (IRR: 0.07, 95%CI 0.05-0.10, p < 0.001) compared with those occurring during 2008-2012. Hib strains have not been isolated from invasive H. influenzae disease cases since 2014; however, non-typeable H. influenzae and H. influenzae type f isolates have been noted as causes of invasive H. influenzae diseases among children <5 years in the post-Hib vaccine era.

CONCLUSIONS

After the governmental subsidization of the Hib vaccine, invasive Hib disease cases decreased dramatically in the study population, as per our surveillance. Continuous surveillance is necessary to monitor the effectiveness of Hib vaccine and for detecting any emerging invasive capsular types.

Nosocomial Outbreak of Upper Respiratory Tract Infection With β-Lactamase-Negative Ampicillin-Resistant Nontypeable Haemophilus influenzae

OBJECTIVETo describe the epidemiologic features of an outbreak of an acute respiratory tract infection (ARI) caused by β-lactamase-negative ampicillin-resistant (BLNAR) nontypeable Haemophilus influenzae (NTHi) in an acute-care ward.DESIGNCross-sectional case-control study.SETTINGAn acute-care ward (ward A) in a general hospital of Kochi in western Japan.METHODSPatients who shared a room with an index patient and all staff in ward A were screened and followed from July 1 to August 31, 2015. Sputum or throat swab samples were collected from participants and tested by culture and polymerase chain reaction (PCR). The association between detected pathogens and ARI development among all participants was examined. A case-control study was conducted to identify risk factors for disease.RESULTSIn total, 78 participants, including the index patient, were enrolled. Of all participants, 27 (34.6%) developed mild respiratory symptoms during a 3-week period: 24 were diagnosed as upper respiratory tract infections, and 3 were diagnosed as lower respiratory tract infections. The presence of BLNAR NTHi was confirmed in 13 participants, and multilocus sequence typing demonstrated that these isolates belonged to sequence type 159. All isolates showed identical pulsed-field gel electrophoresis patterns. The presence of BLNAR NTHi was strongly associated with ARI development, whereas viruses were not associated with the disease. Multivariate analyses demonstrated that a history of contact with the index patient was independently associated with ARI caused by BLNAR NTHi.CONCLUSIONSBLNAR NTHi has the potential to cause upper respiratory tract infections among adults and to spread rapidly in hospital settings.Infect Control Hosp Epidemiol 2018;39:652-659.

Population density profiles of nasopharyngeal carriage of 5 bacterial species in pre-school children measured using quantitative PCR offer potential insights into the dynamics of transmission

Bacterial vaccines can reduce carriage rates. Colonization is usually a binary endpoint. Real time quantitative PCR (qPCR) can quantify bacterial DNA in mucosal samples over a wide range. Using culture and single-gene species-specific qPCRs for Streptococcus pneumoniae (lytA), Streptococcus pyogenes (ntpC), Moraxella catarrhalis (ompJ), Haemophilus influenzae (hdp) and Staphylococcus aureus (nuc) and standard curves against log-phase reference strain broth cultures we described frequency and peak density distributions of carriage in nasopharyngeal swabs from 161 healthy 2-4 y old children collected into STGG broth. In general, detection by qPCR and culture was consistent. Discordance mostly occurred at lower detection thresholds of both methods, although PCR assays for S. pyogenes and S. aureus were less sensitive. Density varied across 5-7 orders of magnitude for the 5 species with the abundant species skewed toward high values (modes: S. pneumoniae log3-4, M. catarrhalis & H. influenzae log4-5 CFU/ml broth). Wide ranges of bacterial DNA concentrations in healthy children carrying these bacteria could mean that different individuals at different times vary greatly in infectiousness. Understanding the host, microbial and environmental determinants of colonization density will permit more accurate prediction of vaccine effectiveness.

Why we need a vaccine for non-typeable Haemophilus influenzae

Nontypeable Haemophilus influenzae (NTHi) is increasingly recognized as emerging pathogen. The routine immunization of infants with conjugated vaccines against H. influenzae type b (Hib) has greatly reduced the incidence of invasive Hib disease; however a marked change in the predominant invasive serotype from Hib to NTHi has occurred. Localized infections where the role of H. influenzae is important, such as otitis media in children and acute exacerbations in chronic obstructive pulmonary disease (COPD) in adults, are almost exclusively associated with NTHi isolates. The implementation of pneumococcal conjugate vaccines has resulted in changes in frequency of nasopharynx colonizing pathogens with an increase of NTHi, although this data is yet under debate. An effective vaccine against NTHi is not currently available. The major challenge in developing a successful vaccine is the intrinsic heterogeneity of NTHi. H. influenzae protein D is used as carrier protein in the licensed 10-valent pneumococcal conjugate vaccine (Synflorix, GlaxoSmithKline), but no robust evidences for protective efficacy against NTHi otitis have been until now obtained. Several other vaccine candidates are under investigations and we hope that significant advancements in vaccine development will be achieved in the next future. Genome-based vaccine strategy might provide an additional useful tool for discovering further vaccine antigens.

Worldwide Lineages of Clinical Pneumococci in a Japanese Teaching Hospital Identified by DiversiLab System

Pneumococcal Molecular Epidemiology Network (PMEN) clones are representatives of worldwide-spreading pathogens. DiversiLab system, a repetitive PCR system, has been proposed as a less labor-and time-intensive genotyping platform alternative to conventional methods. However, the utility and analysis parameters of DiversiLab for identifying worldwide lineages was not established. To evaluate and optimize the performance of DiversiLab for identifying worldwide pneumococcal lineages, we examined 245 consecutive isolates of clinical Streptococcus pneumoniae from all age-group patients at a teaching hospital in Japan. The capsular swelling reaction of all isolates yielded 24 different serotypes. Intensive visual observation (VO) of DiversiLab band pattern difference divided all isolates into 73 clusters. Multilocus sequence typing (MLST) of representative 73 isolates from each VO cluster yielded 51 different STs. Among them, PMEN-related lineages accounted for 63% (46/73). Although the serotype of PMEN-related isolates was identical to that of the original PMEN clone in 70% (32/46), CC156-related PMEN lineages, namely Greece(6B)-22 and Colombia(23F)-26, harbored various capsular types discordant to the original PMEN clones. Regarding automated analysis, genotyping by extended Jaccard (XJ) with a 75% similarity index cutoff (SIC) showed the highest correlation with serotyping (adjusted Rand's coefficient, 0.528). Elevating the SIC for XJ to 85% increased the discriminatory power sufficient for distinguishing two major PMEN-related isolates of Taiwan(19F)-14 and Netherlands(3)-31. These results demonstrated a potential utility of DiversiLab for identifying worldwide lineage of pneumococcus. An optimized parameters of automated analysis should be useful especially for comparison for reference strains by "identification" function of DiversiLab.

[Analysis of Non-serotype b Encapsulated Haemophilus influenzae Isolated from Pediatric Patients]

We analyzed non-serotype b encapsulated Haemophilus influenzae (non-b Hi) isolated from pediatric patients at Chiba Children's Hospital during 2000-2012. Among 3,532 clinical isolates of H. influenzae, there were 57 (1.6%) strains of non-b Hi, 152 (4.3%) of serotype b H. influenzae (Hib), and 3,323 (94.1%) of non-typeable H. influenzae (NTHi). Fifty-seven strains of non-b Hi were serotyped useing the slide agglutination test and PCR. Twenty-nine strains were identified as type e (Hie) and 28 as type f (Hif), and the results according to the slide agglutination test and PCR were completely identical. Whereas 52 of 57 strains (91.2%) were isolated from respiratory specimen, only one Hif strain (1.8%) was isolated from a sterile site. There were 47 (82.4%) β-lactamase-non-producing ampicillin (ABPC)-sensitive strains (BLNAS), 5 (8.8%) β-lactamase-producing strains (BLP), and only 1 (1.8%) β-lactamase-non-producing ABPC-resistant strain (BLNAR). Thus the frequency of non-b Hi was lower than that of Hib. The source of non-b Hi was similar to that of NTHi, which was mainly isolated from respiratory specimen. Antimicrobial resistant pattern of non-b Hi was different from that of Hib in which the frequency of BLP was relatively high, and NTHi in which that of BLNAR was high. An increase of invasive H. influenzae infections caused by NTHi, Hie, and Hif was reported in the countries where Hib vaccine had been widely used. Because it is assumed that invasive non-Hib infection will be predominant in the near future in Japan, serotyping of invasive strains is crucial. Continuous monitoring of distribution of non-b Hi in the clinical isolates of H. influenzae is also important.

The impact of heptavalent pneumococcal conjugate vaccine on the incidence of childhood community-acquired pneumonia and bacteriologically confirmed pneumococcal pneumonia in Japan

Heptavalent pneumococcal conjugate vaccine (PCV7) was introduced to Japan in 2010. We investigated the impact of PCV7 on childhood community-acquired pneumonia (CAP) and pneumococcal pneumonia (PP). Children aged <5 years living in Chiba city, Japan, who were admitted to hospitals were enrolled to estimate the incidence of CAP based on the mid-year population. PP was determined by the presence of Streptococcus pneumoniae in cultured blood and/or sputum samples of CAP patients. The incidence of CAP and S. pneumoniae isolated from PP patients was compared before (April 2008-March 2009) and after (April 2012-March 2013) the introduction of PCV7 immunization. The annual incidence of CAP was reduced [incidence rate ratio 0·81, 95% confidence interval (CI) 0·73-0·90]. When comparing post-vaccine with pre-vaccine periods, the odds ratio for PP incidence was 0·60 (95% CI 0·39-0·93, P = 0·024). PCV7-covered serotypes markedly decreased (66·6% in pre-vaccine vs. 15·6% in post-vaccine, P < 0·01), and serotypes 6C, 15A, 15C and 19A increased. Multidrug-resistant international clones in the pre-vaccine period (Spain6B-2/ST90, Taiwan19F-14/ST236) decreased, while Sweden15A-25/ST63 was the dominant clone in the post-vaccine period. A significant reduction in the incidence of both CAP hospitalizations and culture-confirmed PP of vaccine serotypes was observed at 2 years after PCV7 vaccination.

Radical serotype rearrangement of carried pneumococci in the first 3 years after intensive vaccination started in Hungary

Streptococcus pneumoniae is responsible for a significant amount of morbidity and mortality worldwide. Healthy carriers, mainly young children, are the most important sources of infections. In the current study, we aimed to determine the changes that have occurred since the introduction of PCV-7 in Hungary. Nasal specimens were collected from 1,022 healthy children aged 3-6 years attending day-care centres. After thorough identification, pneumococcal isolates were serotyped, and their antibiotic sensitivity was determined. The carriage rate was found to be 34.9%. A huge serotype rearrangement was detected compared to earlier results, with the previously leading serotype 14 having completely disappeared. Serotypes 11A, 35F, 19A, 6B, 15B, 3 and 38 were most prevalent, and 29 different types were identified in total. The PCV-7 types were responsible for 16.5% of all serotypes, and 36.0% are not covered by any pneumococcal vaccines. The isolates were sensitive to most tested antibiotics, except erythromycin (resistance was 21.6%). Only one penicillin-resistant strain was found. The newly and rapidly emerging non-vaccine serotypes are much more sensitive, except serotype 19A.

CONCLUSION

Due to PCV vaccination, a complete serotype arrangement occurred also in Hungary. The old "paediatric" serotypes were replaced by serotypes 11A, 35F, 19A, 6B, 15B, 3 and 38.

Cost-Effectiveness Evaluation of the 10-Valent Pneumococcal Non-typeable Haemophilus influenzae Protein D Conjugate Vaccine and 13-Valent Pneumococcal Vaccine in Japanese Children

INTRODUCTION

Diseases caused by Streptococcus pneumoniae represent a major public health problem. The purpose of this study was to compare, in the Japanese context, the projected health benefits, costs and cost-effectiveness of the latest generation of pneumococcal conjugate vaccines which may provide important insight into the potential public health impact of interventions in the context of local disease-specific epidemiology.

METHODS

A Markov model was used to compare two vaccination strategies which involve routine infant immunization with either the 13-valent pneumococcal conjugate vaccine (PCV-13; Prevenar 13™, Pfizer, Pearl River, NY, USA) or the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV; Synflorix™, GlaxoSmithKline Biologicals SA, Rixensart, Belgium) over a time horizon of 5 years from the healthcare provider and societal perspectives. Estimates for key model parameters were obtained from locally available databases and published literature. Incremental benefits in terms of costs and quality-adjusted life-year and cost-effectiveness were assessed.

RESULTS

A 3 + 1 vaccination schedule for infants with PHiD-CV is expected to have a similar impact on invasive pneumococcal disease and pneumonia and a larger impact on acute otitis media-related outcomes compared with PCV-13. Assuming price parity for these vaccines, the model projected that vaccination with PHiD-CV would result in cost savings of 1.9 and 3.9 billion Japanese yen from the provider and societal perspectives, respectively. This was largely due to a reduction in highly prevalent acute otitis media. Vaccination with PHiD-CV was expected to generate a gain of 433 quality-adjusted life-years compared to PCV-13 translating into dominance over PCV-13. Sensitivity analyses showed robustness of model outcome to changes in key model parameters and substantiated that the model outcome was consistently driven by the incremental benefit of PHiD-CV in averting acute otitis media.

CONCLUSION

In comparison to PCV-13, vaccination with PHiD-CV is projected to be cost saving for Japan from both the healthcare provider and societal perspectives.

Pathogens penetrating the central nervous system: infection pathways and the cellular and molecular mechanisms of invasion

The brain is well protected against microbial invasion by cellular barriers, such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). In addition, cells within the central nervous system (CNS) are capable of producing an immune response against invading pathogens. Nonetheless, a range of pathogenic microbes make their way to the CNS, and the resulting infections can cause significant morbidity and mortality. Bacteria, amoebae, fungi, and viruses are capable of CNS invasion, with the latter using axonal transport as a common route of infection. In this review, we compare the mechanisms by which bacterial pathogens reach the CNS and infect the brain. In particular, we focus on recent data regarding mechanisms of bacterial translocation from the nasal mucosa to the brain, which represents a little explored pathway of bacterial invasion but has been proposed as being particularly important in explaining how infection with Burkholderia pseudomallei can result in melioidosis encephalomyelitis.