Epidemiology of pneumococcal infections in the elderly

Pneumolysin contributes to dysfunction of nasal epithelial barrier for promotion of pneumococcal dissemination into brain tissue

Streptococcus pneumoniae is one of the major pathogens responsible for bacterial meningitis and neurological sequelae. The present study was conducted to identify a non-hematogenous route used by S. pneumoniae to gain access to brain tissue without causing bacteremia or pneumonia, as well as bacterial and host factors involved in this process. To investigate the molecular mechanisms and dissemination pathways of pneumococcal infection in brain tissue, mice were intranasally inoculated with S. pneumoniae strain EF3030, a clinical isolate from a patient with otitis media. Pneumococci were isolated from the frontal olfactory bulb, caudal cerebrum, and cerebellum, with neither bacteremia nor pneumonia observed in the present model. Immunostaining imaging revealed the presence of S. pneumoniae organisms in olfactory nerve fibers. Knockout of the ply gene encoding pneumolysin (PLY) markedly compromised the ability of the bacterial organisms to disseminate into brain tissue, whereas the dissemination efficiency of the complemented strain was restored to nearly the same level as the wild type. Notably, distinct upregulation of Gli1 and Snail1, which are involved in the transcriptional repression of junctional proteins, along with downregulation of E-cadherin, was detected in nasal lavage samples from mice infected with the wild-type or complemented strain, but not in those from mice infected with the ply mutant. Taken together, the present findings indicate that PLY induces Gli1-Snail1-dependent dysfunction of the nasal epithelial barrier, thus allowing pneumococcal dissemination to brain tissue that occurs in a non-hematogenous manner.IMPORTANCEBacterial meningitis, considered to be caused by bacteremia, can lead to blood-brain barrier disruption and bacterial dissemination into the central nervous system. Despite the availability of intravenously administered antibiotics with cerebrospinal fluid transferability, bacterial meningitis remains associated with high rates of morbidity and mortality. Here, we utilized Streptococcus pneumoniae strain EF3030, clinically isolated from otitis media, for the construction of a murine infection model to investigate the molecular mechanisms by which nasally colonized pneumococci disseminate into brain tissue. The obtained findings indicate that pneumolysin (PLY) induces Gli1-Snail1-dependent dysfunction of the nasal epithelial barrier, which facilitates pneumococcal dissemination to brain tissue in a non-hematogenous manner. Our results support the existence of an alternative route by which S. pneumoniae can reach the central nervous system and indicate the need for the development of novel therapeutic strategies, which would be an important contribution to the clinical management of bacterial meningitis.

Mortality of Invasive Pneumococcal Disease following Introduction of the 13-Valent Pneumococcal Conjugate Vaccine in Greenland

Before the incorporation of the 13-valent pneumococcal conjugate vaccine (PCV13) into the childhood vaccination regimen in Greenland in 2010, Inuit populations experienced a substantial prevalence of invasive pneumococcal disease (IPD). The PCV13 introduction has been shown to markedly reduce the incidence of IPD. This current study estimated the impact of PCV13 introduction on IPD mortality in Greenland. This was a nationwide register-based study using all available data on IPD cases 1995-2020 in Greenland. Thirty-one-day IPD case fatality rates (CFR), and all-cause and mortality rates associated with IPD during the period before the introduction of PCV13 (January 1995 to September 2010) were compared with those observed in the post-PCV13 era (September 2010 to October 2020). Standardized mortality ratios (SMRs) expressed differences in mortality by sex, age, region, ethnicity, comorbidity, and serotype. IPD CFR decreased with 24.5% from the pre- to the post-PCV13 period. SMR in IPD patients decreased by 57% (95% CI, 36-75%), and a reduction occurred in all age groups. While SMR in IPD persons ≥60 years remained virtually unchanged, there were no IPD-related deaths in persons ≤39 years in the post-PCV13 period. In conclusion, IPD-related mortality has decreased in Greenland following PCV13 introduction in 2010 in the country.

The impact of respiratory infections and probiotic use on the nasal microbiota of frail residents in long-term care homes

Background

Residents in long-term care homes, who tend to be of advanced age and frail, are at increased risk of respiratory infections. The respiratory microbiota is known to change with age, but whether these changes contribute to the risk of infection is not known. Our goal was to determine how the nasal microbiota of frail older adults changes during symptoms of influenza-like illness (ILI) and how this may be impacted by enrolment in a placebo-controlled trial testing the feasibility of administering a Lactobacillus rhamnosus GG probiotic to prevent respiratory infection (2014-2017).

Methods

The microbiome of the nasal (mid-turbinate) of 150 residents of long-term care homes was interrogated using 16S rRNA gene sequencing.

Results

We identified a diverse and individualised microbiota which could be separated into nine distinct clusters based on Bray-Curtis distances. Samples collected during symptoms of ILI differed statistically from those collected pre- and post-cold and influenza season, and we observed decreased temporal stability (as measured by movement between clusters) in individuals who experienced ILI compared to those who did not.

Conclusions

The use of probiotics decreased ILI-induced changes to the microbiota; however, it is not clear whether this decrease is sufficient to prevent respiratory illness.

Proteins of Streptococcus pneumoniae Involved in Iron Acquisition

Streptococcus pneumoniae is a human pathogen bacterium capable of using hemoglobin (Hb) and haem as a single iron source but not in presence of lactoferrin. This bacterium has developed a mechanism through the expression of several membrane proteins that bind to iron sources, between them a lipoprotein of 37 kDa called Spbhp-37 (Streptococcus pneumoniae haem-binding protein) involved in iron acquisition. The Spbhp-37 role is to maintain the viability of S. pneumoniae in presence of Hb or haem. This mechanism is relevant during the invasion of S. pneumoniae to human tissue for the acquisition of iron from hemoglobin or haem as an iron source.

Autolysin (lytA) recombinant protein: a potential target for developing vaccines against pneumococcal infections

Purpose

N-acetylmuramoyl-l-alanine amidase known as lytA, is an immunogenic protein that plays an important role in the pathogenesis of Streptococcus pneumoniae. It is highly conserved among S. pneumoniae strains and is absent among other Streptococcus species. In the present study, the level of antibodies against the lytA recombinant protein was evaluated in healthy individuals' sera.

Materials and Methods

DNA was extracted from S. pneumoniae ATCC 49619 to amplify lytA gene by polymerase chain reaction assay. The lytA amplicon and pET28a vector were separately double digested using Nde-1 and Xho1 restriction enzymes and then ligated together with ligase enzyme. The recombinant plasmid was expressed in Escherichia coli BL21 strain and the lytA recombinant protein purified using nickel-nitrilotriacetic acid affinity chromatography. Western blot was carried to detect lytA recombinant protein. Sixty healthy individual's sera (at three age groups: group 1, <2; group 2, 2–40; and group 3, 60–90 years old) were collected and the titers of anti-lytA antibodies were determined.

Results

The lytA gene was highly expressed in E. coli BL21 host. The recombinant lytA protein was purified and confirmed by western blotting. Tukey test analysis showed that there were no significant differences among the age groups considering the anti-lytA titer of 10. However, at the anti-lytA titer of 60, significant differences were observed between group 1 vs. group 2 (p<0.001); group 1 vs. group 3 (p=0.003), and group 2 vs. group 3 (p=0.024).

Conclusion

The lytA protein seems to be a highly immunogenic antigen and a potential target for developing vaccines against pneumococcal infections.

Case Studies and Literature Review of Pneumococcal Septic Arthritis in Adults

We saw an increase in this condition related to emergence of Streptococcus pneumoniae serotype 23B.

We conducted a retrospective study on all cases of pneumococcal septic arthritis (SA) in patients >18 years of age reported to the Picardie Regional Pneumococcal Network in France during 2005–2016. Among 1,062 cases of invasive pneumococcal disease, we observed 16 (1.5%) SA cases. Although SA is uncommon in adult patients, the prevalence of pneumococcal SA in the Picardie region increased from 0.69% during 2005–2010 to 2.47% during 2011–2016 after introduction of the pneumococcal 13-valent conjugate vaccine. We highlight the emergence of SA cases caused by the 23B serotype, which is not covered in the vaccine.

Bacteriophages Could Be a Potential Game Changer in the Trajectory of Coronavirus Disease (COVID-19)

The pandemic of the coronavirus disease (Covid-19) has caused the death of at least 270,000 people as of the 8th of May 2020. This work stresses the potential role of bacteriophages to decrease the mortality rate of patients infected by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The indirect cause of mortality in Covid-19 is miscommunication between the innate and adaptive immune systems, resulting in a failure to produce effective antibodies against the virus on time. Although further research is urgently needed, secondary bacterial infections in the respiratory system could potentially contribute to the high mortality rate observed among the elderly due to Covid-19. If bacterial growth, together with delayed production of antibodies, is a significant contributing factor to Covid-19's mortality rate, then the additional time needed for the human body's adaptive immune system to produce specific antibodies could be gained by reducing the bacterial growth rate in the respiratory system of a patient. Independently of that, the administration of synthetic antibodies against SARS-CoV-2 viruses could potentially decrease the viral load. The decrease of bacterial growth and the covalent binding of synthetic antibodies to viruses should further diminish the production of inflammatory fluids in the lungs of patients (the indirect cause of death). Although the first goal could potentially be achieved by antibiotics, I argue that other methods may be more effective or could be used together with antibiotics to decrease the growth rate of bacteria, and that respective clinical trials should be launched.

Both goals can be achieved by bacteriophages. The bacterial growth rate could potentially be reduced by the aerosol application of natural bacteriophages that prey on the main species of bacteria known to cause respiratory failure and should be harmless to a patient. Independently of that, synthetically changed bacteriophages could be used to quickly manufacture specific antibodies against SARS-CoV-2. This can be done via a Nobel Prize awarded technique called “phage display.” If it works, the patient is given extra time to produce their own specific antibodies against the SARS-CoV-2 virus and stop the damage caused by an excessive immunological reaction.

PspA facilitates evasion of pneumococci from bactericidal activity of neutrophil extracellular traps (NETs)

Pneumococcal strains are variably resistant to killing by neutrophil extracellular traps (NETs). We hypothesize that this variability in resistance is due to heterogeneity in pneumococcal surface protein A (PspA), a structurally diverse virulence factor of Streptococcus pneumoniae. Pneumococcal strains showed variability in induction of NETs and in susceptibility to killing by NETs. The variability in susceptibility to NETs-mediated killing of pneumococcal strains is attributed to PspA, as strains lacking the surface expression of PspA were significantly more sensitive to NETs-mediated killing compared to the wild-type strains. Using pspA switch mutants we were further able to demonstrate that NETs induction and killing by NETs is a function of PspA as mutants with switch PspA demonstrated donor phenotype. Antibody to PspA alone showed an increase in induction of NETs, and NETs thus generated were able to trap and kill pneumococci. Pneumococci opsonized with antibody to PspA showed increase adherence to NETs but a decrease susceptibility to killing by NETs. In conclusion we demonstrate a novel role for pneumococcal PspA in resisting NETs mediated killing and allowing the bacteria to escape containment by blocking binding of pneumococci to NETs.

Influence of Obesity on Pneumococcus Infection Risk in the Elderly

Obesity negatively affects immune function and host defense mechanisms. Obesity is associated with chronic activation of the innate immune system and consequent local and systemic inflammation which contribute to pathologic conditions such as type-2 diabetes mellitus, cancer, psoriasis, atherosclerosis, and inflammatory bowel disease. Individuals with obesity have increased susceptibility to contract viral, bacterial, and fungal infections and respond sub-optimally to vaccination. In this review, we summarize research findings on the effects of obesity on immune responses to respiratory tract infections (RTI), focusing on Streptococcus pneumoniae ("pneumococcus") infection, which is a major cause of morbidity and mortality in the US, causing community-acquired infections such as pneumonia, otitis media and meningitis. We show that the risk of infection is higher in elderly individuals and also in individuals of certain ethnic groups, although in a few reports obesity has been associated with better survival of individuals admitted to hospital with pneumococcus infection, a phenomenon known as "obesity paradox." We discuss factors that are associated with increased risk of pneumococcal infection, such as recent infection with RTI, chronic medical conditions, and immunosuppressive medications.

Persistence of antibodies 1 year after sequential administration of the 13-valent pneumococcal conjugate vaccine and the 23-valent pneumococcal polysaccharide vaccine in adults

Vaccination with the 13-valent pneumococcal conjugate vaccine (PCV13) followed ≥ 1 year by the 23-valent pneumococcal polysaccharide vaccine (PPSV23) is recommended for immunocompetent adults ≥ 65 years of age in the United States. This study assessed antipneumococcal opsonophagocytic activity (OPA) geometric mean titers (GMTs) to PCV13 in PPSV23-naive and PPSV23-preimmunized adults 1 year after a second vaccine dose. Two parent studies were conducted previously: (1) PPSV23 vaccine–naive subjects (60–64 years of age at enrollment) received PCV13 followed by PCV13 or PPSV23 1 year later or PPSV23 followed by PCV13 1 year later; and (2) subjects (≥ 70 years of age at enrollment) vaccinated with PPSV23 ≥ 5 years before study entry received PCV13 or PPSV23 followed by PCV13 1 year later. Overall, 962 subjects (PPSV23-naive, n = 519; PPSV23-preimmunized, n = 443) who received both vaccinations in the parent studies were enrolled. Numerically higher OPA GMTs persisted for at least 1 year after administration of PCV13 as the initial vaccine (PCV13/PPSV23 or PCV13/PCV13) compared with those who received PPSV23 either 1 or 5 years prior (PPSV23/PCV13). This impairment in antibody responses to subsequent PCV13 vaccination produced by initial PPSV23 vaccination persisted for at least 1 year. OPA GMTs were numerically higher for most serotypes 1 year after 2 doses of PCV13 compared with 1 year after the first PCV13 dose. These data suggest PCV13 should be given first if both vaccines are to be administered, higher immune responses were achieved when PCV13 was given first and persisted at least 1 year (ClinicalTrials.gov Identifier: NCT01025336).

The Epidemiology and Biostatistics of Pneumococcus

Invasive infections caused by Streptococcus pneumoniae, such as pneumonia, meningitis, and bacteremia, are a major cause of morbidity and mortality in young children and older adults worldwide. The introduction of pneumococcal conjugate vaccines into national childhood immunization programs has led to large and sustained reductions in the incidence of invasive pneumococcal disease across all age groups. Here we describe the epidemiology and biostatistics of pneumococcal disease as well as the impact of vaccination on the burden of pneumococcal disease globally.

Severity and properties of cardiac damage caused by Streptococcus pneumoniae are strain dependent

Streptococcus pneumoniae is an opportunistic Gram-positive pathogen that can cause invasive disease. Recent studies have shown that S. pneumoniae is able to invade the myocardium and kill cardiomyocytes, with one-in-five adults hospitalized for pneumococcal pneumonia having a pneumonia-associated adverse cardiac event. Furthermore, clinical reports have shown up to a 10-year increased risk of adverse cardiac events in patients formerly hospitalized for pneumococcal bacteremia. In this study, we investigated the ability of nine S. pneumoniae clinical isolates, representing eight unique serotypes, to cause cardiac damage in a mouse model of invasive disease. Following intraperitoneal challenge of C57BL/6 mice, four of these strains (D39, WU2, TIGR4, and 6A-10) caused high-grade bacteremia, while CDC7F:2617-97 and AMQ16 caused mid- and low-grade bacteremia, respectively. Three strains did not cause any discernible disease. Of note, only the strains capable of high-grade bacteremia caused cardiac damage, as inferred by serum levels of cardiac troponin-I. This link between bacteremia and heart damage was further corroborated by Hematoxylin & Eosin and Trichrome staining which showed cardiac cytotoxicity only in D39, WU2, TIGR4, and 6A-10 infected mice. Finally, hearts infected with these strains showed varying histopathological characteristics, such as differential lesion formation and myocytolysis, suggesting that the mechanism of heart damage varied between strains.

Cost-effectiveness analysis of 13-valent pneumococcal conjugate vaccine versus 23-valent pneumococcal polysaccharide vaccine in an adult population in South Korea

In South Korea, the National Immunization Program offers a 23-valent pneumococcal polysaccharide vaccine (PPSV23) for the elderly; however, the 13-valent pneumococcal conjugate vaccine (PCV13) is not included, and vaccination is not offered to younger, at-risk populations. This study offers a comparative analysis of PCV13 and PPSV23 in Korea's adults, stratified by age and risk group. A Markov model with a lifetime horizon was developed from the healthcare perspective. Data sources included the Health Insurance Review & Assessment Service, Korea Centre for Disease Control & Prevention and Korean medical institutions. An expert panel tested data validity. The CAPiTA trial and Cochrane meta-analysis were used to obtain vaccine effectiveness data. Regardless of co-morbidity, when the sequential PCV13-PPSV23 strategy was compared to that using PPSV23-only, in elderly populations, the incremental cost-effectiveness ratio (ICER) was 3,300 USD per quality-adjusted life years (QALY). For the risk group aged ≥65 years, the ICER of the addition of PCV13 over the existing PPSV23-only strategy was 3,404 USD/QALY. However, on replacing PPSV23 with PCV13, for all elderly populations, an ICER of 1,421 USD/QALY resulted; for the risk group aged ≥65 years, the ICER was 1,736 USD/QALY. For the 18-64 year-old risk group, the sequential PCV13-PPSV23 strategy yielded an ICER of 3,629 USD/QALY over the PPSV23-only strategy, and 6,643 USD/QALY compared to no vaccination. Thus, the PCV13→PPSV23 combination strategy for elderly populations was found to be a cost-effective alternative to the current National Immunization Program regardless of co-morbidity. This finding was the same as that for younger, at-risk populations.

Exacerbation of Bronchiectasis

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Indirect (herd) protection, following pneumococcal conjugated vaccines introduction: A systematic review of the literature

BACKGROUND

Pneumococcal diseases are major causes of morbidity among adults, especially those over 50years of age. While pneumococcal conjugated vaccines (PCV's) impact on pneumococcal disease rates among children is well established, the extent of its impact on adult pneumococcal related illness remains unclear. The aim of this systematic literature review was to describe the impact of PCV introduction to childhood national immunization programs worldwide on PCV-naive adult population.

METHODS

A systematic literature search was performed using the PubMed database. The search was limited to articles written in English and published between January 2000 and February 2016. Studies evaluating pneumococcal disease rates in individuals over 5years of age were included. Independent extraction of articles was performed by the two authors. Search terms included: Pneumococcal conjugated vaccine, herd, indirect, adults, and pneumonia.

RESULTS

Forty-nine articles meeting the selection criteria were identified, 39 regarding invasive pneumococcal disease (IPD, one on meningitis only), 8 regarding pneumonia, and 2 on both IPD and pneumonia. The majority of reports were from the US, UK and Canada. Considerable variability in the data sources, quality and completeness was observed. While most studies reported either statistically significant reduction or insignificant changes in IPD and pneumonia disease rates in adults following PCV nationwide implementation, few studies reported statistically significant increase in pneumococcal disease rates, these were mainly from countries with low PCV coverage rates and/or inadequate surveillance.

CONCLUSION

Invasive pneumococcal diseases and pneumonia rates among the adult population decreased in most countries following PCV introduction into the NIP. This indirect effect on older population seems to be dependent on PCV coverage rates and time from PCV nationwide implementation. Adults >65years old seem to benefit the most from PCV introduction.

Characterization of Spbhp-37, a Hemoglobin-Binding Protein of Streptococcus pneumoniae

Streptococcus pneumoniae is a Gram-positive microorganism that is the cause of bacterial pneumonia, sinusitis and otitis media. This human pathogen also can cause invasive diseases such as meningitis, bacteremia and septicemia. Hemoglobin (Hb) and haem can support the growth and viability of S. pneumoniae as sole iron sources. Unfortunately, the acquisition mechanism of Hb and haem in this bacterium has been poorly studied. Previously we identified two proteins of 37 and 22 kDa as putative Hb- and haem-binding proteins (Spbhp-37 and Spbhp-22, respectively). The sequence of Spbhp-37 protein was database annotated as lipoprotein without any function or localization. Here it was immunolocalized in the surface cell by transmission electron microscopy using specific antibodies produced against the recombinant protein. The expression of Spbhp-37 was increased when bacteria were grown in media culture supplied with Hb. In addition, the affinity of Sphbp-37 for Hb was determined. Thus, in this work we are presenting new findings that attempt to explain the mechanism involved in iron acquisition of this pathogen. In the future these results could help to develop new therapy targets in order to avoid the secondary effects caused by the traditional therapies.

Pneumococcal vaccination: what have we learnt so far and what can we expect in the future?

Individuals <2 years and ≥ 50 years of age, as well as those with other specific risk factors, are especially vulnerable to invasive pneumococcal disease (IPD). Conjugate vaccines have been developed against encapsulated bacteria such as Streptococcus pneumoniae to provide improved immune responses. The 7-valent pneumococcal conjugate vaccine (PCV7) has significantly reduced the burden of vaccine-type pneumococcal diseases in children, including invasive disease and pneumonia and acute otitis media. There have also been significant declines in antimicrobial resistance in 7-valent vaccine serotypes and carriage of S. pneumoniae in the post-PCV7 era. Two to three years after the introduction of PCV13, there is emerging, global evidence of a reduced burden of pneumococcal diseases in children, including declines in IPD (UK and Germany) and nasopharyngeal carriage of PCV13 serotypes (Portugal and France). The functional immunogenicity of PCV13 in individuals ≥ 50 years of age has been demonstrated in clinical trials in comparison with the 23-valent pneumococcal polysaccharide vaccine and for children and adults 6 to 49 years of age. Between 2011 and 2013, PCV13 received market authorisation by the European Medicines Agency (EMA) for these additional age groups and is now available in Europe for the prevention of pneumococcal disease in all age groups.

A retrospective analysis of hospital discharge records for S. pneumoniae diseases in the elderly population of Florence, Italy, 2010-2012

Invasive pneumococcal diseases (IPD) and community acquired pneumonia (CAP) represent two of the major causes of out-patient visits, hospital admissions and deaths in the elderly. In Tuscany (Italy), in the Local Health Unit of Florence, a project aimed at implementing an active surveillance of pneumococcal diseases in the hospitalized elderly population started in 2013. The aim of this study is to show the results of the retrospective analysis (2010-2012) on hospital discharge records (HDRs) related to diseases potentially due to S. pneumoniae, using a selection of ICD9-CM codes. All ordinary hospitalizations (primary and secondary diagnoses) of the elderly population were included (11 245 HDRs). Among a population of about 200 000 inhabitants ≥65 y, the hospitalization rate (HR) increased with increasing age and was higher in males in all age groups. Almost all hospitalizations (95%) were due to CAP, only 5% were invasive diseases. Only few cases of CAP were specified as related to S. pneumoniae, the percentage was higher in case of meningitis (100%) or septicemia (22%). In-hospital deaths over the three-year period were 1703 (case fatality rate: 15%). The risk of dying, being hospitalized for a disease potentially attributable to pneumococcus (as primary diagnosis) increased significantly with age (P < 0.001), the odds ratio (OR) per increasing age year was 1.06 (95% CI 1.05-1.07) and was higher in patients with co-existing medical conditions with respect to patients without comorbidities. Currently, an active surveillance system on S. pneumoniae diseases with the inclusion of bio-molecular tests (RT-PCR), is a key step to assess the effectiveness of the PCV13 vaccine (13-valent pneumococcal conjugate vaccine) in the elderly population after implementation of vaccination policies. The results of this study will provide the comparator baseline data for the evaluation of a possible immunization programme involving one or more cohorts of the elderly in Tuscany.

Recommendations for pneumococcal immunization outside routine childhood immunization programs in Western Europe

The global burden of pneumococcal diseases is high, with young children and adults ≥50 years of age at highest risk of infection. Two types of vaccine are available for the prevention of pneumococcal diseases caused by specific Streptococcus pneumoniae serotypes: the pneumococcal polysaccharide vaccine (PPV23) and the pneumococcal conjugate vaccine (PCV7, PCV10, and PCV13). Despite pneumococcal immunization programs in adults and children, the burden in adults has remained high. Most European countries have national or local/regional vaccination recommendations. The objective of this review was to provide an overview of the government recommendations for pneumococcal vaccination outside routine childhood vaccination programs for 16 Western European countries as of August 2014. We found that recommendations for pneumococcal immunization across Europe are complex and vary greatly among countries in terms of age groups and risk groups recommended for vaccination, as well as which vaccine should be administered. Clarifying or simplifying these recommendations and improving their dissemination could help to increase pneumococcal vaccine uptake and decrease the high burden of pneumococcal diseases in adults, both through a direct effect of the vaccine and via a herd effect in unvaccinated individuals.

Evolving role of 13-valent pneumococcal conjugate vaccine in clinical practice

Since the introduction of 7-valent pneumococcal conjugate vaccine (PCV7), PCVs with extended coverage have become available, and there is emerging global evidence that these vaccines, in particular PCV13, have further reduced rates of invasive pneumococcal disease compared with PCV7. The present article aims to address emerging topics related to PCV13 use in routine clinical practice; specifically: (1) the potential role of high-valent PCVs in reducing pneumococcal disease burden; (2) the impact of PCVs on nasopharyngeal carriage and how this may contribute to reductions in otitis media and pneumonia, as well as the prevalence of resistant pneumococcal strains; (3) new PCV13 indications and (4) importance of schedule adherence for PCV in the prevention of cases of vaccine serotype-specific invasive pneumococcal disease. The beneficial effects of PCVs in protecting individuals from a wide spectrum of pneumococcal diseases can be increased by improving the vaccine coverage and adhering to the recommended vaccination schedules. There is increasing evidence that PCV13 has reduced much of the post-PCV7 burden of pneumococcal diseases in the pediatric community, including reducing pneumococcal colonization and the incidence of invasive pneumococcal disease and mucosal diseases. This has also led to a reduction in antibiotic-resistant pneumococcal diseases. The role of PCV13 in clinical practice is evolving, with PCV13 now available for children and adolescents between the ages of 6 weeks and 17 years, thus ensuring that children in all age groups can be protected against vaccine-serotype pneumococcal diseases. Continued surveillance is warranted to monitor the impact of PCV13 on disease burden.

Estimating the burden of hospitalization for pneumococcal pneumonia in a general population aged 50 years or older and implications for vaccination strategies

Streptococcus pneumoniae is a major cause of human infectious diseases worldwide. Despite this documented evidence, data on pneumococcal disease rates among general populations are scant because of the frequent lack of cultural identification. In this study we propose a model for estimating the burden of pneumococcal pneumonia on hospitalizations. The study was performed by analyzing administrative and clinical data of patients aged 50 years or older, resident in Sicily, and hospitalized, from 2005 to 2012. Demographic information, admission/discharge dates, discharge status, and up to 6 discharge diagnoses coded according to ICD-9 CM were collected for each hospitalized patient. During the 8-year study period, a total of 72,372 hospitalizations with at least one ICD-9 CM diagnosis code suggestive of all-cause pneumonia were recorded. Of these, 1943 (2.7%) hospitalizations had specific ICD-9 CM diagnosis codes for pneumococcal pneumonia. According to the proposed model, 16,541 (22.9%) pneumonia out of all-cause pneumonia was estimated to be attributable to S. pneumoniae. Pneumococcal pneumonia and model-estimated pneumococcal pneumonia had mean hospitalization rates of 13.4 and 113.3/100,000, respectively, with a decreasing temporal trend. The risk of hospitalization for pneumococcal pneumonia was strongly correlated with age (P<0.001). Our model provides data usable to construct suitable decisional models for the decision-makers and could allow to the responsibles of healthcare facilities to assess the budget impact if they hypothesize to offer vaccination for pneumococcal disease to certain cohorts of subjects aged 50 years or older. In our area, the high estimated hospitalization rates among adults aged ≥65 years suggest the need to implement effective preventive strategies (e.g., vaccination) tailored for these groups.

A cross-sectional study to investigate pneumococcal vaccination in the elderly in a low income county: patient knowledge, awareness, and attitudes of vaccination and prevalence rates by socioeconomic status

BACKGROUND

Pneumonia represents the leading cause of infection-related death and the fifth cause of overall mortality, in the elderly. With increasing age, the human immune system undergoes characteristic changes which lead to increased incidence and severity of infectious diseases and to insufficient protection following vaccination as antibody response of elderly vaccines are weaker and decline faster.

OBJECTIVE

Knowledge and Attitude toward Pneumonia and its Vaccination in elderly patients.

RESULT

Among low SES, 54.9% (549/1000) while from high SES, 91.8% (918) responded that they had heard about pneumonia before (P<0.05). 79.5% (795/1000) patients of high SES had heard about pneumococcal vaccination while only 28.8% (288/1000) patients from low SES had heard about pneumococcal vaccine. Only 2.3% of low SES patients were immunized for pneumococcal vaccine while 16.5% high SES patients were vaccinated. Reported reason for not being immunized were; did not hear, no body advised, vaccine is too expensive, and ignored thinking it is not necessary.

METHOD

We conducted a cross-sectional study on 2000 elderly patients who were admitted in medicine and surgery wards of Civil Hospital Karachi and Aga Khan University Hospital Karachi from the period of October to December 2012 to determine their knowledge and attitude toward pneumonia and its vaccination in elderly. Study group was divided into low and high socio-economic status on the basis of patients coming to government Hospital i.e., civil hospital and private hospital i.e., Aga khan hospital. Data was collected through convenient sampling technique. Exclusion criteria were patients below 60 years and those who didn't give consent to be part of study.

CONCLUSION

Aside from introducing public awareness program about elderly vaccination at state level, free of cost vaccination of elderly individuals should be done.

Pneumococcal infection in adults: burden of disease

To overview the present global burden of pneumococcal disease is important because new preventive measures such as the pneumococcal conjugate vaccine 13 are currently being evaluated. Pneumococcal disease is roughly divided into non-invasive and invasive disease. The burden of non-invasive pneumococcal disease in adults is mainly determined by community-acquired pneumonia. Pneumococcal pneumonia has high incidence rates and carries a high mortality risk, especially in the elderly. Within the cluster of invasive pneumococcal diseases, pneumonia also represents the most common infectious source. Incidence and mortality rates of both non-invasive and invasive disease have changed as a result of pneumococcal vaccination in children. However, especially elderly patients with comorbidities remain vulnerable to morbidity and mortality caused by pneumococcal disease. The current review summarizes the current knowledge on the epidemiology including outcome of the main clinical forms of pneumococcal disease, with a special focus on elderly patients. Furthermore, the economic burden and future vaccine strategies are briefly discussed.

Preventing pneumococcal disease in the elderly: recent advances in vaccines and implications for clinical practice

Streptococcus pneumoniae remains a major cause of morbidity and mortality throughout the world. To date, after the introduction of routine childhood immunization, elderly people (i.e., persons aged 65 years or older) suffer the greatest burden of pneumococcal disease in developed countries. At present, two anti-pneumococcal vaccines are available for use in adults: the 23-valent pneumococcal polysaccharide vaccine (PPV23) and the 13-valent protein-polysaccharide conjugate vaccine (PCV13). This article reviews current data about the burden of pneumococcal disease in the elderly, as well as evidence for immunogenicity, clinical efficacy, and possible cost-effectiveness of both vaccines. The main advantage of PCV13 is that it may be more effective than PPV23, but a major limitation is that it is directed against strains that are likely to be greatly reduced in the population since its introduction in childhood immunization. The main disadvantage of PPV23 is that it may be less effective than PCV13 against vaccine-type infections but a major advantage is that it may provide protection against ten additional serotypes. To date, expert committees have not changed recommendations for pneumococcal vaccination in adults. However, at present, they are evaluating different alternatives (basically, maintaining PPV23, changing from PPV23 to PCV13 in some groups, or adding PCV13 for all or some target adult population subgroups). Critical data (clinical efficacy reported in ongoing trials and magnitude of indirect effects of pediatric PCV13 programs) needed to make a well-informed decision could be available during 2013. Considering all concerns over indirect effects and replacement strains following the use of polysaccharide-based vaccines, efforts should be directed toward developing vaccines, such as protein-based pneumococcal vaccines, with potential serotype-independent protection. Meanwhile, according to current recommendations, PPV23 should continue to be used for high-risk adults and all elderly people (with and without additional high-risk conditions). Although it is only moderately effective, it has a considerable serotype coverage and at-risk persons can benefit from the vaccination. High-risk individuals could also obtain a benefit from adding PCV13, but more data are needed before a universal recommendation can be made.

The potential for pneumococcal vaccination in Hajj pilgrims: expert opinion

Hajj is the annual pilgrimage to Mecca in the Kingdom of Saudi Arabia, and is one of the largest mass gathering events in the world. Acute respiratory tract infections are very common during Hajj, primarily as a result of close contact among pilgrims, intense congestion, shared accommodation and air pollution. A number of vaccines are (or have been) recommended for Hajj pilgrims in recent years. Several additional vaccines could significantly reduce the morbidity and mortality at Hajj and should be considered in health recommendations for pilgrims. Pneumococcal vaccines (particularly for those aged >65 years) are widely available, and have been shown to reduce the burden of disease associated with Streptococcus pneumoniae infection. Importantly, a considerable percentage of Hajj pilgrims have pre-existing illnesses or are elderly, both important risk factors for pneumococcal infection. While there are substantial gaps that need to be addressed regarding our knowledge of the exact burden of disease in Hajj pilgrims and the effectiveness of pneumococcal vaccination in this population, S. pneumoniae may be an important cause of illness among this group of travelers. It can be assumed that the majority of pneumococcal serotypes circulating during Hajj are included in the existing pneumococcal vaccines.

Immunization for the elderly

The morbidity and mortality of vaccine-preventable diseases among older adults are high. Despite the benefits of elderly vaccination, vaccination rates remain low and especially among some minority groups. Specific strategies for improving the rate of vaccination have been developed for medical offices and clinics, hospitals, and other health care institutions. There are vaccines that are recommended routinely for the elderly while other vaccines are recommended in certain circumstances. Knowing the indications, contraindications, and adverse reactions to the recommended vaccines for the elderly is very important to the primary care physicians.

Pneumococcal carriage among indigenous Warao children in Venezuela: serotypes, susceptibility patterns, and molecular epidemiology

Little attention has been paid to pneumococcal carriage and disease in Amerindians from Latin America. The Warao people, an indigenous population from Venezuela, live in the delta of the Orinoco River in geographically isolated communities with difficult access to medical care. To obtain insight into pneumococcal carriage and the theoretical coverage of pneumococcal vaccines in this population, we investigated pneumococcal colonization, serotype, and genotype distribution among Warao children in 9 distinct, geographically isolated communities in the Delta Amacuro area in the northeast of Venezuela. From April 2004 through January 2005, a total of 161 Streptococcus pneumoniae isolates were recovered from single nasopharyngeal swab samples obtained from 356 children aged 0-72 months. The overall pneumococcal carriage rate was 49%, ranging from 13% to 76%, depending on the community investigated and the age of the children (50% among children aged <2 years and 25% among children aged >2 years). The most frequent serotypes were 23F (19.5% of isolates), 6A (19.5%), 15B (10.4%), 6B (9.1%), and 19F (7.2%). The theoretical coverage of the 7-valent pneumococcal conjugate vaccine, including the cross-reactive nonvaccine serotype 6A, was 65%. A total of 26% of the isolates were resistant to first-line antibiotics, with 70% of these strains being covered by the 7-valent pneumococcal conjugate vaccine. Restriction fragment end labelling analysis revealed 65 different genotypes, with 125 (80%) of the isolates belonging to 27 different genetic clusters, suggesting a high degree of horizontal spread of pneumococcal strains in and between the villages. The high colonization rates and high (registered) acute respiratory tract infection morbidity and mortality in this part of Venezuela suggest that Warao children are at increased risk for pneumococcal disease and, therefore, benefit from vaccination.

Cost-effectiveness of vaccinating for invasive pneumococcal disease in the elderly in the Lazio region of Italy

Pneumococcal vaccination among the elderly is currently recommended in several western countries. We estimated the cost-effectiveness of a hypothetical vaccination campaign of 65+ year olds in the Lazio region (Italy). Baseline net costs per event averted and life-year gained, at 2001 prices, were euro 34,681 (95%CI: euro 28,699 to euro 42,929) and euro 23,361, respectively (95%CI: euro 16,419 to euro 38,297). Lower bacteraemic pneumonia incidence and vaccine effectiveness increased the net cost per life-year gained (ICER) to euro 53,899 and euro 74,313, respectively; in the best-case scenario the ICER was euro 4249. The case definition of invasive pneumococcal disease and, consequently, vaccine effectiveness are major uncertainties in countries with low incidence of pneumonia.

Modelling hospital admissions for lower respiratory tract infections in the elderly in England

Despite the importance of lower respiratory-tract infection (LRI) in causing hospitalizations in elderly patients (>or=65 years of age) and recent advances in vaccine development, a complete picture of the causative organisms is not available. All hospital discharge diagnoses (ICD-10 code) for LRI in elderly patients in England during 1995-1998 were reviewed. Using known seasonality in potential causative agents of LRI, the contribution of different respiratory pathogens to hospitalizations coded as 'unspecified LRI' was estimated by multiple linear regression analysis. Ninety-seven per cent of 551633 LRI-associated diagnoses had no specific organism recorded. From the statistical model the estimated proportions of admissions attributable to different pathogens were applied to calculate estimated hospitalization rates: 93.9 hospitalizations/10000 population aged >or=65 years due to S. pneumoniae, 22.9 to influenza virus, 22.3 to H. influenzae, 17.0 to whooping cough, and 12.8 to respiratory syncytial virus. There is enormous potential to improve health using existing vaccines and those under development.

Acute infections as a means of cancer prevention: opposing effects to chronic infections?

PURPOSE

Epidemiological studies have found an inverse association between acute infections and cancer development. In this paper, we review the evidence examining this potentially antagonistic relationship.

METHODS

In addition to a review of the historical literature, we examined the recent epidemiological evidence on the relationship between acute infections and subsequent cancer development in adult life. We also discuss the impact of chronic infections on tumor development and the influence of the immune system in this process.

RESULTS

Exposures to febrile infectious childhood diseases were associated with subsequently reduced risks for melanoma, ovary, and multiple cancers combined, significant in the latter two groups. Epidemiological studies on common acute infections in adults and subsequent cancer development found these infections to be associated with reduced risks for meningioma, glioma, melanoma and multiple cancers combined, significantly for the latter three groups. Overall, risk reduction increased with the frequency of infections, with febrile infections affording the greatest protection. In contrast to acute infections, chronic infections can be viewed as resulting from a failed immune response and an increasing number have been associated with an elevated cancer risk.

CONCLUSION

Infections may play a paradoxical role in cancer development with chronic infections often being tumorigenic and acute infections being antagonistic to cancer.

Streptococcus pneumoniae: description of the pathogen, disease epidemiology, treatment, and prevention

Streptococcus pneumoniae causes significant morbidity and mortality. Children younger than 2 years and individuals older than 65 years experience the highest rates of pneumococcal disease. Efforts to treat pneumococcal disease have been complicated by increasing resistance to antimicrobials. Prevention efforts have included the pneumococcal polysaccharide vaccines and the pneumococcal conjugate vaccines, with use of these vaccines targeted to those at highest risk for disease. Information and background on S. pneumoniae and pneumococcal disease are provided. Vaccines targeted at this pathogen are reviewed, and the clinical trials that evaluated their safety, efficacy, and effectiveness are summarized. Also provided are recommendations for use of these vaccines.

Predictors of pneumococcal polysaccharide vaccination among patients at three inner-city neighborhood health centers

BACKGROUND

Despite the availability of pneumococcal polysaccharide vaccine (PPV), vaccination rates are modest, and racial disparity in these rates is known to occur.

OBJECTIVE

The purpose of this study was to identify determinants of patient-reported receipt of PPV among patients from 3 inner-city health centers that serve large numbers of minority and disadvantaged patients.

METHODS

In 2003, a random sample of patients from 3 inner-city health centers was surveyed by computer-assisted telephone interview concerning their vaccination status and their attitudes and beliefs about PPV. The questionnaire was based on the theory of reasoned action, which emphasizes the contributions to behavioral intention of cognitive beliefs (including the likelihood of consequences), the value of those consequences, and normative beliefs. Factor analysis was conducted to examine whether survey items specific to attitudes about PPV would group together; the variance of the components resulting from the factor analysis was expressed in eigenvalues. Logistic regression analyses were conducted to determine which factors, demographic characteristics, and health habits were independently associated with PPV status.

RESULTS

Of 674 patients sent introductory letters (13 of whom were ineligible), 325 (49%) completed the interview with usable data. These patients were primarily aged > or = 65 years (52% [168/325]), female (69% [223/325]), and white (57% [174/306]), and had an annual household income < 20,000 dollars (61% [174/287]). Vaccination status or intention to be vaccinated was unknown for 25 persons, reducing the sample to 300. Of these respondents, 59% (178) reported vaccination, 9% (26) intended to be vaccinated within 6 months, and 32% (96) had no intention of being vaccinated. Vaccination rates were 76% (119/157) for responders aged > or = 65 years and 41% (59/143) for responders aged 50 to 64 years (P < 0.001). Logistic regression analyses found 3 variables that were significantly associated with the likelihood of vaccination: age > or = 65 years; frequency of physician visits; and timing of the last complete physical examination. The factor analysis with varimax rotation identified 2 factors that increased the likelihood of reporting ever receiving PPV: attitudes about PPV and social influences (eigenvalue = 2.69), and beliefs about pneumonia risk and vaccine efficacy (eigenvalue = 1.24). When these factors were added to the model, the effects of age and frequency of seeing a physician became nonsignificant. Compared with those having a complete physical examination < 1 year ago, those having an examination 1 to 2 years ago (odds ratio [OR] = 0.16; 95% CI = 0.04-0.69) or > 2 years ago (OR = 0.10; 95% CI = 0.01-0.78) were less likely to be vaccinated. Those agreeing with the attitudes and social influence factor were more likely to be vaccinated (OR = 8.24; 95% CI = 3.97-17.12), as were those agreeing with the pneumonia risk and vaccine efficacy factor (OR = 2.63; 95% CI = 1.20-5.80).

CONCLUSIONS

Attitudes about vaccination and a clinician's recommendation are the most powerful predictors of PPV status. Efforts to raise rates of vaccination and reduce racial disparities should emphasize communication of clinicians' recommendations to patients.

Community-acquired bacteraemic pneumococcal pneumonia in adults: effect of diminished penicillin susceptibility on clinical outcome

Pneumococcal pneumonia remains a common disease with a high mortality rate. Between 1995 and 2000, we prospectively analyzed 95 consecutive adult cases of community-acquired bacteraemic pneumococcal pneumonia treated in a single centre. The incidence of pneumococcal resistance to penicillin increased from 19 to 50% during the study period. Multivariate analysis showed that only age and recent hospitalization were independently associated with fatal outcome. The proportion of penicillin-resistant strains was slightly but not significantly higher among patients who died before the fourth hospital day than among those who died later. Patients who died before D4 were more likely to have a recent history of hospitalization, cancer and/or chemotherapy. It thus appears that infection by a resistant pneumococcal strain is not in itself a gravity factor in this setting, but that their acquisition is associated with pejorative clinical features.

Pneumococcal immunization in older adults: implications for the long-term-care setting

OBJECTIVES

To compare the efficacy of the polysaccharide pneumococcal vaccine in older adults between clinical trial and observational studies and to discuss the implications for long-term-care facilities (LTCFs).

DATA SOURCE

A Medline search (to April 2003).

STUDY SELECTION

All meta-analyses of randomized and quasi-randomized trials of pneumococcal vaccines with placebo or no treatment were sought. All cohort or case-control studies were sought.

DATA SYNTHESIS

Of the 16 individual randomized clinical trials included in the reviews, 8 compared pneumococcal vaccine in individuals 55 years and older individuals. Only one study specifically addressed LTCF residents. Although no significant protective effect of the vaccine in elderly subpopulations was found, on the basis of wide confidence intervals and small subpopulation sample sizes, beneficial effects, particularly for pneumococcal bacteremia, could not be ruled out. Of the individual observational studies, 11 specifically evaluated vaccine efficacy in older adults. Vaccine efficacy was demonstrated in 9 of the 11 studies with no protective effect was shown in 2 studies.

CONCLUSION

Although the pooling of clinical trial data does not demonstrate significant efficacy of the pneumococcal polysaccharide vaccine in subgroups of older adults, these subgroup studies lacked power to show significant differences. Observational studies repeatedly demonstrate efficacy in older adults, and the vaccine has been demonstrated to be cost-effective and safe. It is strongly promoted by U.S. and Canadian advisory committees. On the basis of this available evidence, the pneumococcal polysaccharide vaccine should currently be recommended for older adults, especially those who are residents of LTCFs.

Persistence of antibody response to pneumococcal capsular polysaccharides in vaccinated long term-care residents in Brazil

To evaluate the immunogenicity of 23-valent pneumococcal polysaccharide vaccine in 52 nursing homes residents aged > or = 60 years, IgG antibodies to serotypes 1, 5, 6B, and 8 were measured by ELISA and compared before, and 1 and 12 months following vaccination. A significant immunological response for all serotypes was observed at 1 month after vaccination. The mean increase in antibody concentration was highly variable and ranged from 1.6 to 2.7. After 1 year, the mean concentrations remained significantly higher than prior to vaccination for serotypes 1, 6B, and 8, although there was a decrease in all mean IgG concentrations. Antibody levels were higher in men than in women, before and after immunisation. Post-vaccination values tended to be lower among subjects aged >75 years. Reduction in IgG concentrations by 33% 1 year after vaccination suggests that revaccination of institutionalised elderly people may be needed.

Drug Therapy in Transplant Recipients

Elderly patients with end-stage organ failure are now more frequently undergoing transplantation. Medication management in this population is challenging because of the combination of multiple comorbidities, polypharmacy, and immunological, pharmacokinetic and pharmacodynamic changes attributable to the aging process. Immunosuppressive medications can exacerbate pre-existing medical conditions and promote the development of disease processes. Cardiovascular disorders, such as hypertension, coronary artery disease, congestive heart failure and arrhythmias are common in elderly transplant recipients, and account for most of the deaths in this population. Blood pressure, blood glucose and cholesterol control is of particular concern because elderly transplant recipients frequently have or develop these complications. Elderly transplant recipients are commonly receiving anticoagulation therapy with warfarin and are at a higher risk of bleeding, especially if they have renal dysfunction. Infectious complications occur frequently in the transplanted population, with pneumonia being the most common infection seen in hospitalised patients. Attention to vaccination for the prevention of influenza and pneumococcal infections is important because of the increased risk of these diseases in this population. Depression itself has been associated with decreased survival in older individuals, and depression in elderly transplant recipients may be reversible with the administration of pharmacological agents. Effective long-term care of transplant recipients demands an understanding of how particular medications affect clinical evaluation and treatment. This article addresses some of the practical issues surrounding medication management and prevention of these particular problems in elderly transplant recipients.

Pneumococcal carriage results in ganglioside-mediated olfactory tissue infection

Streptococcus pneumoniae cause considerable morbidity and mortality, with persistent neurological sequelae, particularly in young children and the elderly. It is widely assumed that carriage occurs through direct mucosal colonization from the environment whereas meningitis results from invasion from the blood. However, the results of published studies can be interpreted that pneumococci may enter the brain directly from the nasal cavity by axonal transport through olfactory nerves. This hypothesis is based on findings that (i) teichoic acid of the pneumococcal cell wall interact with gangliosides (GLS), (ii) the interaction of GLS with cholera toxin leads to axonal transport through the olfactory nerves into the brain, and (iii) viruses enter the brain through axonal transport into olfactory nerves. After nasal inoculation, we observe high numbers of pneumococci in nasal washes and the olfactory nerves and epithelium. Significant numbers of pneumococci also infected the olfactory bulbs, brain, and the trigeminal ganglia. The absence of bacteremia in this model makes it unlikely that the bacteria entered the brain from the blood stream. Recovery of colony-forming units from the brain, lungs, olfactory nerves, and epithelium and nasal washes was inhibited by incubating pneumococci with GLS before nasal inoculation. These findings, confirmed by PCR and immunohistochemistry, support a GLS-mediated process of infection and are consistent with pneumococci reaching the brain through retrograde axonal transport.

Pneumococcal vaccination and revaccination of older adults

As individuals advance in age, the risk of infection, bacteremia, and mortality caused by Streptococcus pneumoniae rises. Retrospective data demonstrate that the licensed penumococcal polysaccharide vaccine (PPV) is effective in older persons in reducing serotype-specific invasive disease. PPV demonstrates good immunogenicity in older adults, generally comparable to that in younger subjects, although certain cohorts respond less well. The response to PPV is T cell independent, however, and does not elicit immunologic memory. The duration of the anti-capsular polysaccharide antibody response appears to wane as early as 3 years after vaccination. In older persons, revaccination induces an antibody response, although it may not be as strong as that from the initial vaccine. While revaccination of older adults has been recommended, clinical efficacy has not yet been proven. Measures of antibody function may be at least as important in determining protection as are quantitative antibody levels. Additional studies of immunogenicity, particularly regarding revaccination, will facilitate the design of an optimal pneumococcal vaccination policy. Research into conjugate- and protein-based pneumococcal vaccines, which elicit T-cell-dependent responses and induce immunologic memory, is needed in older persons. In the meantime, administering to PPV to recommended groups should be a public health priority.

Prevalence of penicillin non-susceptible invasive pneumococcal disease in the elderly in Scotland, 1992-99

Penicillin resistance of Pneumococci is a problem in several European countries. Therefore, we examined 510 invasive pneumococcal isolates, collected between 1992 and 1999 via a national network of diagnostic laboratories covering the entire population of Scotland, for penicillin susceptibility, in order to determine the prevalence, site of infection and serogroup/type distribution of penicillin-resistant Pneumococci in the elderly (> or = 65 y). Of the 510 isolates, 91.6% (n = 467) were from blood, 4.7% (n = 24) from other sterile sites and 3.7% (n = 19) from cerebrospinal fluid. The prevalence of penicillin non-susceptible isolates during the study period was 9%. An increase in the proportion of Pneumococci non-susceptible to penicillin was detected from 1996 onwards, from 10.8% in 1996 to 14.3% in 1999. There were 2 isolates with high-level penicillin resistance, both of which were of serotype 14, accounting for 4.3% (2/46) of all non-susceptible isolates. Penicillin non-susceptible isolates belonged to the following serogroups: 14 (32.6%); 9 (30.4%); 6 (19.6%); 23 (10.9%); and 19 (6.5%). The leading non-susceptible serotype/group varied according to the specimen type: serotype 14 for blood and serogroup 9 for all other sterile sites. Current polysaccharide and new 7-, 9- and 11-valent conjugate vaccine formulations included the serogroups responsible for all the penicillin non-susceptible isolates detected. Therefore vaccination represents the most effective strategy for decreasing the burden of drug resistance. Constant surveillance of the patterns of antibiotic non-susceptible isolates, the site of infection and the serogroup/type are necessary in order to select antibiotic therapy and establish vaccination policy for the prevention of invasive pneumococcal disease.

Pneumococcal polysaccharide revaccination: immunoglobulin g seroconversion, persistence, and safety in frail, chronically ill older subjects

OBJECTIVES

To determine the 1-month postpneumococcal polysaccharide-revaccination immunoglobulin G (IgG) antibody response, its persistence at 1 year, and tolerability of revaccination in frail, chronically ill older nursing facility residents.

DESIGN

Prospective study conducted between December 1998 and July 2000.

SETTING

Six skilled nursing facilities in the Minneapolis-St. Paul, Minnesota, metropolitan area.

PARTICIPANTS

Sixty-seven subjects aged 65 and older having received primary vaccination with pneumococcal polysaccharide vaccine (PPV) at least 5 years before enrollment.

INTERVENTION

Revaccination with one dose of 23-valent PPV.

MEASUREMENTS

Adverse events and concentrations of seven individual pneumococcal polysaccharide type-specific IgG antibodies (against serotypes 4, 6B, 9V, 14, 18C, 19F, 23F) and their aggregate before and 1 and 12 months after revaccination.

RESULTS

A significant increase in all individual and aggregate median antibody concentrations over baseline was observed 1 month after revaccination. However, after 1 year, the increase remained significant only for serotypes 6B and 18C and the aggregate parameter. One month after revaccination, the mean increase in antibody concentration over baseline was significantly greater than 1.4-fold for six of the seven serotypes and the aggregate. However, the increase was not significantly greater than 1.4 at 1 year for any of the serotypes or the aggregate. Minor, self-limited localized adverse reactions and systemic reactions occurred in 11.3% of the subjects.

CONCLUSIONS

In frail, chronically ill older nursing facility residents, revaccination with 23-valent PPV at least 5 years after primary vaccination (whether primary vaccination occurred before or after age 65) is associated with a significant, albeit brief, immunological response for most of the serotypes tested. Revaccination was well tolerated.

The changing epidemiology of bacterial meningitis and invasive non-meningitic bacterial disease in scotland during the period 1983-99

We reviewed population-based laboratory reports of invasive meningococcal, pneumococcal, Haemophilus influenzae, Group B Streptococcus (GBS) and Listeria monocytogenes isolates in order to examine the changing epidemiology of meningitis and invasive non-meningitic disease (INMD) caused by these 5 pathogens in the 2 periods before (1983-91) and after (1992-99) routine use of H. influenzae type B conjugate vaccine (Hib) in Scotland. Neissieria meningitidis was the most common cause of meningitis, accounting for 39.2% of cases of meningitis in 1983-91 and 47% of cases in 1992-99, followed by H. influenzae (31%), Streptococcus pneumoniae (22.4%), GBS (3.9%) and L. monocytogenes (3.5%) in 1983-91 and S. pneumoniae (36.3%), H. influenzae (7.8%), GBS (6.1%) and L. monocytogenes (2.8%) in 1992-99. The important epidemiological features of meningitis and INMD caused by these 5 pathogens between 1983-91 and 1992-99 include: 1. The incidence of bacterial meningitis due to S. pneumoniae and GBS was stable; 2. S. pneumoniae was the predominant cause of INMD in both periods; 3. The incidences of INMD caused by N. meningitidis, GBS and S. pneumoniae increased, by 27%, 55% and 56%, respectively; 4. Decreases in the incidences of bacterial meningitis (by 50%) and INMD (by 50%) due to L. monocytogenes were detected; and 5. There were dramatic reductions in the proportions of bacterial meningitis (by 92%) and INMD (by 56%) due to H. influenzae in vaccinated and non-vaccinated individuals. Continued surveillance is necessary to monitor the disease trend, population at risk, serotype distribution and antimicrobial susceptibility in order to implement appropriate public health interventions against invasive bacterial disease.

A direct comparison of the antigen-specific antibody profiles of intravenous immunoglobulins derived from US and UK donor plasma

BACKGROUND AND OBJECTIVES

Intravenous immunoglobulin (IVIG) is used in a range of immunodeficiency states that require a broad spectrum of protective antibodies to a range of common pathogens. A comparison of the antigen-specific antibody profile of preparations of an IVIG (Vigam) derived from US and UK sourced plasma was performed, and these preparations were also compared with three other IVIG products from different manufacturers.

MATERIALS AND METHODS

Antibodies against a range of bacterial and viral pathogens were measured by immunoassay.

RESULTS

Similar profiles were found for Vigam made from UK and US source plasma and also for the other three IVIGs tested, but some specific differences were observed.

CONCLUSIONS

IVIG preparations have a similar therapeutic spectrum of antibodies when prepared from plasma sourced either from the UK or the US.

Influenza and pneumococcal vaccination in Scottish nursing homes: coverage, policies and reasons for receipt and non-receipt of vaccine

A national survey was carried out to determine the coverage of influenza and pneumococcal vaccines, policies, reasons for receipt, non-receipt of vaccine and strategies to improve vaccine coverage in Scottish nursing homes. Of the 550 nursing homes, 72% (394) participated in the study. Overall coverage was 85% for influenza vaccine in 2001-2002 season and 11% for pneumococcal vaccine in the last 5-year period. Only 6% (23/394) of homes were reported to have a systematic immunization record. The most frequently stated reasons for improved coverage of both vaccines were clear immunization policies (76%), awareness and education for staff and residents (68%), and consent on behalf of the incompetent residents (66%). The presence of vaccination policies was higher for influenza vaccine than pneumococcal vaccine expressed as verbal agreement (27% versus 3%), written policies with set target (24% versus 5%) and written policies without set target (17% versus 2%). Advice from the members of the community health care team was the principal reason for the receipt of both vaccines. The predominant reasons for non-receipt of vaccine were refusal by residents and family members (both vaccines) and lack of advice from general practitioners (pneumococcal vaccine). The substantial disparity in coverage of influenza and pneumococcal vaccine reflects the lack of national recommendations and policies for reimbursements for pneumococcal vaccination. These data suggest that greater efforts are needed to improve prevention behaviors of health care professionals and the public, organized vaccine delivery strategies and systematic vaccination documents to increase influenza and pneumococcal vaccination rates in nursing homes and other long-term care facilities.

Rethinking recommendations for use of pneumococcal vaccines in adults

Streptococcus pneumoniae remains a major cause of disease worldwide; the emergence of antibiotic-resistant strains emphasizes the importance of disease prevention by use of vaccines. Recent studies have provided information that is useful for the evaluation of current vaccine recommendations. Recommendations target most people who are at high risk for invasive pneumococcal disease. However, higher risk has also been identified for African Americans and smokers, but these groups are not specifically targeted by current recommendations. The vaccine is effective against invasive disease in immunocompetent people, although studies in immunocompromised subjects have found few subgroups in which the vaccine appears to be effective. Questions with regard to optimal timing and indications for revaccination remain a challenge, because the duration of protection and effectiveness of revaccination remain unknown. New pneumococcal vaccines appear promising but will need to be tested against the performance of the polysaccharide vaccine. Improving delivery of the currently available pneumococcal polysaccharide vaccine to adults who will benefit should be a high priority.

Exponentially increased risk of infectious death in older renal transplant recipients

BACKGROUND

The benefit of renal transplantation for patients with end-stage renal disease (ESRD) has been well documented. This benefit is seen throughout all age ranges of patients. However, it has been documented that older renal transplant recipients are at increased risk for death because of infectious causes when compared with younger recipients. The present study addresses whether this increased risk merely parallels an age-related increase in infectious mortality or is reflective of a particular vulnerability in older renal transplant recipients.

METHODS

Patients wait-listed and transplanted between 1988 and 1997 were analyzed utilizing the United States Renal Data System (USRDS) database. The primary study end point was patient death secondary to infection. Secondary end points included death secondary to cardiovascular cause and malignancy. Cox-proportional hazard models were utilized with all pertinent variables.

RESULTS

Death related to infectious cause increased exponentially in transplanted patients with increasing age (slope = 2.90.34x), while it increased linearly (slope = 1.9x + 8.6) with increasing age for those patients on the waiting list. Overall mortality increases with age were equal between the wait-listed and transplanted groups.

CONCLUSIONS

The overall survival benefit of transplantation is maintained in the older age groups. However, renal transplantation is associated with an increased risk for infectious death beyond the expected age-related increased risk in patients on the renal transplant waiting list. This may have an impact on future immunosuppressive regimens in this population.

Pneumococcal infection and vaccination in the elderly

The burden of pneumococcal disease among elderly people is not widely known. In most countries, the annual incidence of invasive pneumococcal disease in elderly people is most probably >50 cases/100000 persons. Over the past 20 years, only the United States has used pneumococcal vaccine to any appreciable extent, yet among all vaccine-preventable diseases, pneumococcal infections account for the largest proportion of still unprevented illness in Western Europe. Retrospective studies show that vaccination prevents invasive pneumococcal disease. Pneumococcal vaccination appears to be more cost-effective than any other medical intervention commonly used in the elderly. As new data confirm the benefits of vaccination of the elderly against pneumococcal infections, vaccine use has increased in recent years associated with a decline in invasive disease.