Influence of pneumococcal serotype group on outcome in adults with bacteraemic pneumonia

Global distribution and characteristics of pneumococcal serotypes in adults

The introduction of pneumococcal conjugate vaccines (PCVs) into pediatric national immunization programs (NIP) has significantly reduced invasive pneumococcal diseases and pneumococcal pneumonia caused by PCV serotypes in adults due to herd immunity. However, diseases caused by PCV13 serotypes persist, mainly serotype 3, known for its severity. With the reduction in PCV13 serotypes, diseases caused by non-PCV13 serotypes increased. Residual and emerging serotypes vary regionally; serotype 8 in Europe and South Africa, and serotype 4 in the US and Canada. PCV20 and PCV21 were recently developed, which can prevent residual and emerging pneumococcal diseases where herd immunity is well-established. In countries that have not introduced PCV into pediatric NIP, the pneumococcal disease burden due to PCV serotypes is still marked. Given that serotype distribution varies by region and evolves over time, this review aimed to discuss serotype distribution and disease severity in adults across countries to support future pneumococcal vaccine strategies.

Complicated pneumococcal pneumonia in the era of higher-valent pneumococcal conjugate vaccines: a systematic literature review and meta-analysis, 2001-2022

PURPOSE

To estimate pneumococcal conjugate vaccine (PCV) national program impact on pneumococcal complicated pneumonia (PnCP) based on changes in PnCP population-based incidence, PnCP proportion of all-cause complicated pneumonia (or invasive pneumococcal disease), and PnCP serotype distribution.

METHODS

MEDLINE, EMBASE, and Global Index Medicus articles (2001-March 2022) reporting laboratory-confirmed PnCP studies were stratified by age group, outcome measure, PCV program period(s) (pre-PCV, transition, and post-PCV), serotype distribution (based on serotyping methodology used), and PCV serotype formulation. Random effect meta-analysis of the total number of serotyped isolates within each study was used to calculate pooled serotype-specific percentages.

RESULTS

Of 1360 publications screened, the 134 studies included from 30 countries differed widely by methodological approaches. Pediatric PnCP incidence tended to decline from pre-PCV to post-PCV periods, as did PnCP as a proportion of all-cause complicated pneumonia from transition to post-PCV periods. Studies describing changes in serotype distribution by PCV program period applied detection methods that varied from pre-PCV period microbiological culture with Quellung serotyping to in the transition and post-PCV periods molecular methods like PCR. Meta-analysis revealed near elimination of pediatric PCV7-serotype PnCP between pre- and post-PCV, while the PCV13nonPCV7 percentage increased from 51.1% pre-PCV period to 76.5% in the transition period, remaining stable post-PCV period. Non-PCV13 serotypes increased slightly from low baseline numbers. Adult data were lacking or inconsistent.

CONCLUSIONS

Although studies were heterogeneous, pediatric PnCP incidence and proportion tended to decline from pre-PCV to post-PCV periods, and PCV13nonPCV7 serotype distribution percentage remained unchanged from transition to post-PCV period. Standardization of PnCP surveillance methods, definitions, and reporting is needed to evaluate accurately PCV program impact.

Systematic review on serotypes distribution of pneumococcal pneumonia in adults and the elderly

BACKGROUND

Pneumococcal pneumonia is a major cause of morbidity and mortality among adults, especially those over 65 years of age. Understanding pneumococcal serotype-specific epidemiology in adults and elderly is necessary to inform vaccination policies and to guide the inclusion of serotypes in pneumococcal vaccines. This study aimed to identify the serotypes causing pneumonia in the elderly.

METHODS

A systematic review search was performed using the PubMed database from 1984 to 2020. The search was limited to articles written in English. Studies assessing pneumococcal pneumonia in adults were included. Meta-analysis, other systematic literature reviews and case-reports were excluded. Studies published after the introduction of vaccines (PPSV23 and PCVs) were included.

RESULTS

Forty studies were included. The most common serotype identified in the majority of the articles in adults was the serotype 3 followed by serotypes 19A and 11A. Those serotypes are included in current vaccines. Emergence of non-vaccine serotypes was also observed.

CONCLUSION

Pneumococcal pneumonia remains a high burden in the elderly despite the existence of vaccines for many years. In 2019, nearly 1.4 million deaths were attributable to pneumococcal pneumonia (50% of whom were over 70 years old) and was the leading cause of deaths from infectious disease worldwide. The study highlights the importance of constant monitoring serotypes emerging in this population to better target vaccination strategies.

Mice fatal pneumonia model induced by less-virulent Streptococcus pneumoniae via intratracheal aerosolization

Aim: Animal models of fatal pneumonia caused by Streptococcus pneumoniae (Spn) have not been reliably generated using many strains of less virulent serotypes.Materials & methods: Pulmonary infection of a less virulent Spn serotype1 strain in the immunocompetent mice was established via the intratracheal aerosolization (ITA) route. The survival, local and systemic bacterial spread, pathological changes and inflammatory responses of this model were compared with those of mice challenged via the intratracheal instillation, intranasal instillation and intraperitoneal injection routes.Results: ITA and intratracheal instillation both induced fatal pneumonia; however, ITA resulted in better lung bacterial deposition and distribution, pathological homogeneity and delivery efficiency.Conclusion: ITA is an optimal route for developing animal models of severe pulmonary infections.

Impaired IgM Memory B Cell Function Is Common in Coeliac Disease but Conjugate Pneumococcal Vaccination Induces Robust Protective Immunity

Coeliac disease (CD) is associated with hyposplenism, an acquired impairment of spleen function associated with reduced IgM memory B cells and increased susceptibility to serious pneumococcal infection. Little is known about the immune implications of hyposplenism in CD or the optimal pneumococcal vaccination strategy. In this study, the immune effects of hyposplenism in CD, and the accuracy of screening approaches and protective responses induced by two different pneumococcal vaccines were examined. Active and treated CD cohorts, and healthy and surgically splenectomised controls underwent testing for the presence of Howell-Jolly bodies and pitted red cells, spleen ultrasound, and immune assessment of IgM memory B cell frequency and IgM memory B cell responses to T cell-dependent (TD) or T cell-independent (TI) stimulation. Responses following conjugate (TD) and polysaccharide (TI) pneumococcal vaccination were compared using ELISA and opsonophagocytic assays. Although hyposplenism is rare in treated CD (5.1%), functional B cell defects are common (28-61%) and are not detected by current clinical tests. Conjugate pneumococcal vaccination induced superior and sustained protection against clinically relevant serotypes. Clinical practice guidelines in CD should recommend routine pneumococcal vaccination, ideally with a conjugate vaccine, of all patients in lieu of hyposplenism screening.

Associated Factors of Pneumonia in Individuals with Chronic Obstructive Pulmonary Disease (COPD) Apart from the Use of Inhaled Corticosteroids

Inhaled corticosteroids (ICSs) are widely used in chronic obstructive pulmonary disease (COPD) and in combination with long-acting β2 agonists (LABAs) to reduce exacerbations and improve patient lung function and quality of life. However, ICSs have been associated with an increased risk of pneumonia in individuals with COPD, although the magnitude of this risk remains unclear. Therefore, it is difficult to make informed clinical decisions that balance the benefits and adverse effects of ICSs in people with COPD. There may be other causes of pneumonia in patients with COPD, and these causes are not always considered in studies on the risks of using ICSs in COPD. We consider it very useful to clarify these aspects in assessing the influence of ICSs on the incidence of pneumonia and their role in the treatment of COPD. This issue has important implications for current practice and the evaluation and management of COPD, since COPD patients may benefit from specific ICS-based treatment strategies. Many of the potential causes of pneumonia in patients with COPD can act synergistically, so they can be included in more than one section.

Promoting Fc-Fc interactions between anti-capsular antibodies provides strong immune protection against Streptococcus pneumoniae

Streptococcus pneumoniae is the leading cause of community-acquired pneumonia and an important cause of childhood mortality. Despite the introduction of successful vaccines, the global spread of both non-vaccine serotypes and antibiotic-resistant strains reinforces the development of alternative therapies against this pathogen. One possible route is the development of monoclonal antibodies (mAbs) that induce killing of bacteria via the immune system. Here, we investigate whether mAbs can be used to induce killing of pneumococcal serotypes for which the current vaccines show unsuccessful protection. Our study demonstrates that when human mAbs against pneumococcal capsule polysaccharides (CPS) have a poor capacity to induce complement activation, a critical process for immune protection against pneumococci, their activity can be strongly improved by hexamerization-enhancing mutations. Our data indicate that anti-capsular antibodies may have a low capacity to form higher-order oligomers (IgG hexamers) that are needed to recruit complement component C1. Indeed, specific point mutations in the IgG-Fc domain that strengthen hexamerization strongly enhance C1 recruitment and downstream complement activation on encapsulated pneumococci. Specifically, hexamerization-enhancing mutations E430G or E345K in CPS6-IgG strongly potentiate complement activation on S. pneumoniae strains that express capsular serotype 6 (CPS6), and the highly invasive serotype 19A strain. Furthermore, these mutations improve complement activation via mAbs recognizing CPS3 and CPS8 strains. Importantly, hexamer-enhancing mutations enable mAbs to induce strong opsonophagocytic killing by human neutrophils. Finally, passive immunization with CPS6-IgG1-E345K protected mice from developing severe pneumonia. Altogether, this work provides an important proof of concept for future optimization of antibody therapies against encapsulated bacteria.

The role of adenosine in alcohol-induced respiratory suppression

Alcohol-related poisoning is the foremost cause of death resulting from excessive acute alcohol consumption. Respiratory failure is crucial to the pathophysiology of fatal alcohol poisoning. Alcohol increases accumulation of extracellular adenosine. Adenosine suppresses breathing. The goal of this investigation was to test the hypothesis that adenosine signaling contributes to alcohol-induced respiratory suppression. In the first experiment, the breathing of mice was monitored following an injection of the non-selective adenosine receptor antagonist caffeine (40 mg/kg), alcohol (5 g/kg), or alcohol and caffeine combined. Caffeine reduced alcohol-induced respiratory suppression suggesting that adenosine contributes to the effects of alcohol on breathing. The second experiment utilized the same experimental design, but with the blood brain barrier impermeant non-selective adenosine receptor antagonist 8-sulfophenyltheophylline (8-SPT, 60 mg/kg) instead of caffeine. 8-SPT did not reduce alcohol-induced respiratory suppression suggesting that adenosine is contributing to alcohol-induced respiratory suppression in the central nervous system. The third and fourth experiments used the same experimental design as the first, but with the selective A1 receptor antagonist DPCPX (1 mg/kg) and the selective A2A receptor antagonist istradefylline (3.3 mg/kg). Istradefylline, but not DPCPX, reduced alcohol-induced respiratory suppression indicating an A2A receptor mediated effect. In the fifth experiment, alcohol-induced respiratory suppression was evaluated in Adk+/- mice which have impaired adenosine metabolism. Alcohol-induced respiratory suppression was exacerbated in Adk+/- mice. These findings indicate that adenosinergic signaling contributes to alcohol-induced respiratory suppression. Improving our understanding of how alcohol affects breathing may lead to better treatment strategies and better outcomes for patients with severe alcohol poisoning.

Ethanol Consumption Induces Nonspecific Inflammation and Functional Defects in Alveolar Macrophages

Chronic alcohol drinking is associated with increased susceptibility to viral and bacterial respiratory pathogens. In this study, we use a rhesus macaque model of voluntary ethanol self-administration to study the effects of long-term alcohol drinking on the immunological landscape of the lung. We report a heightened inflammatory state in alveolar macrophages (AMs) obtained from ethanol (EtOH)-drinking animals that is accompanied by increased chromatin accessibility in intergenic regions that regulate inflammatory genes and contain binding motifs for transcription factors AP-1, IRF8, and NFKB p-65. In line with these transcriptional and epigenetic changes at the basal state, AMs from EtOH-drinking animals generate elevated inflammatory mediator responses to lipopolysaccharides and respiratory syncytial virus. However, the transcriptional analysis revealed an inefficient induction of interferon-stimulated genes with EtOH in response to the respiratory syncytial virus, suggesting disruption of antimicrobial defenses. Correspondingly, AMs from EtOH-drinking animals exhibited transcriptional shifts indicative of increased oxidative stress and oxidative phosphorylation, which was coupled with higher cytosolic reactive oxygen species and mitochondrial potential. This heightened oxidative stress state was accompanied by decreased ability to phagocytose bacteria. Bulk RNA and assay for transposase-accessible chromatin sequencing data further revealed reduced expression and chromatin accessibility of loci associated with tissue repair and maintenance with chronic EtOH drinking. Similarly, analysis of single-cell RNA sequencing data revealed shifts in cell states from tissue maintenance to inflammatory responses with EtOH. Collectively, these data provide novel insight into mechanisms by which chronic EtOH drinking increases susceptibility to infection in patients with alcohol use disorders.

Ethanol Intoxication Impairs Respiratory Function and Bacterial Clearance and Is Associated With Neutrophil Accumulation in the Lung After Streptococcus pneumoniae Infection

Alcohol consumption is commonplace in the United States and its prevalence has increased in recent years. Excessive alcohol use is linked to an increased risk of infections including pneumococcal pneumonia, mostly commonly caused by Streptococcus pneumoniae. In addition, pneumonia patients with prior alcohol use often require more intensive treatment and longer hospital stays due to complications of infection. The initial respiratory tract immune response to S. pneumoniae includes the production of pro-inflammatory cytokines and chemokines by resident cells in the upper and lower airways which activate and recruit leukocytes to the site of infection. However, this inflammation must be tightly regulated to avoid accumulation of toxic by-products and subsequent tissue damage. A majority of previous work on alcohol and pneumonia involve animal models utilizing high concentrations of ethanol or chronic exposure and offer conflicting results about how ethanol alters immunity to pathogens. Further, animal models often employ a high bacterial inoculum which may overwhelm the immune system and obscure results, limiting their applicability to the course of human infection. Here, we sought to determine how a more moderate ethanol exposure paradigm affects respiratory function and innate immunity in mice after intranasal infection with 10⁴ colony forming units of S. pneumoniae. Ethanol-exposed mice displayed respiratory dysfunction and impaired bacterial clearance after infection compared to their vehicle-exposed counterparts. This altered response was associated with increased gene expression of neutrophil chemokines Cxcl1 and Cxcl2 in whole lung homogenates, elevated concentrations of circulating granulocyte-colony stimulating factor (G-CSF), and higher neutrophil numbers in the lung 24 hours after infection. Taken together, these findings suggest that even a more moderate ethanol consumption pattern can dramatically modulate the innate immune response to S. pneumoniae after only 3 days of ethanol exposure and provide insight into possible mechanisms related to the compromised respiratory immunity seen in alcohol consumers with pneumonia.

Age-Related Intestinal Dysbiosis and Enrichment of Gut-specific Bacteria in the Lung Are Associated With Increased Susceptibility to Streptococcus pneumoniae Infection in Mice

The portion of the global population that is over the age of 65 is growing rapidly and this presents a number of clinical complications, as the aged population is at higher risk for various diseases, including infection. For example, advanced age is a risk factor for heightened morbidity and mortality following infection with Streptococcus pneumoniae. This increased vulnerability is due, at least in part, to age-related dysregulation of the immune response, a phenomenon termed immunosenescence. However, our understanding of the mechanisms influencing the immunosenescent state and its effects on the innate immune response to pneumonia remain incomplete. Recently, a role for the gut microbiome in age-specific alterations in immunity has been described. Here, we utilized a murine model of intranasal Streptococcus pneumoniae infection to investigate the effects of age on both the innate immune response and the intestinal microbial populations after infection. In aged mice, compared to their younger counterparts, infection with Streptococcus pneumoniae led to increased mortality, impaired lung function and inadequate bacterial control. This poor response to infection was associated with increased influx of neutrophils into the lungs of aged mice 24 h after infection. The exacerbated pulmonary immune response was not associated with increased pro-inflammatory cytokines in the lung compared to young mice but instead heightened expression of immune cell recruiting chemokines by lung neutrophils. Bacterial 16S-rRNA gene sequencing of the fecal microbiome of aged and young-infected mice revealed expansion of Enterobacteriaceae in the feces of aged, but not young mice, after infection. We also saw elevated levels of gut-derived bacteria in the lung of aged-infected mice, including the potentially pathogenic symbiote Escherichia coli. Taken together, these results reveal that, when compared to young mice, Streptococcus pneumoniae infection in age leads to increased lung neutrophilia along with potentially pathogenic alterations in commensal bacteria and highlight potential mechanistic targets contributing to the increased morbidity and mortality observed in infections in age.

Alcohol Use and the Risk of Communicable Diseases

The body of knowledge on alcohol use and communicable diseases has been growing in recent years. Using a narrative review approach, this paper discusses alcohol's role in the acquisition of and treatment outcomes from four different communicable diseases: these include three conditions included in comparative risk assessments to date-Human Immunodeficiency Virus (HIV)/AIDS, tuberculosis (TB), and lower respiratory infections/pneumonia-as well as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) because of its recent and rapid ascension as a global health concern. Alcohol-attributable TB, HIV, and pneumonia combined were responsible for approximately 360,000 deaths and 13 million disability-adjusted life years lost (DALYs) in 2016, with alcohol-attributable TB deaths and DALYs predominating. There is strong evidence that alcohol is associated with increased incidence of and poorer treatment outcomes from HIV, TB, and pneumonia, via both behavioral and biological mechanisms. Preliminary studies suggest that heavy drinkers and those with alcohol use disorders are at increased risk of COVID-19 infection and severe illness. Aside from HIV research, limited research exists that can guide interventions for addressing alcohol-attributable TB and pneumonia or COVID-19. Implementation of effective individual-level interventions and alcohol control policies as a means of reducing the burden of communicable diseases is recommended.

Prognostic factors for mortality in invasive pneumococcal disease in adult: a system review and meta-analysis

Risk factors associated with mortality in invasive pneumococcal disease remain unclear. The present work is a meta-analysis of studies that enrolled only patients with invasive pneumococcal disease and reported on mortality. Potentially eligible reports were identified from PubMed, CHAHL, and Web of Science, comprising 26 reports in total. Overall mortality for invasive pneumococcal disease was reported as 20.8% (95% confidence interval (CI) 17.5–24%). Factors associated with mortality were age (odds ratio (OR) 3.04, 95% CI 2.5–3.68), nursing home (OR 1.62, 95% CI 1.13–2.32), nosocomial infection (OR 2.10, 95% CI 1.52–2.89), septic shock (OR 13.35, 95% CI 4.54–39.31), underlying chronic diseases (OR 2.34, 95% CI 1.78–3.09), solid organ tumor (OR 5.34, 95% CI 2.07–13.74), immunosuppressed status (OR 1.67, 95% CI 1.31–2.14), and alcohol abuse (OR 3.14, 95% CI 2.13–4.64). Mortality rates with invasive pneumococcal disease remained high, and these findings may help clinicians provide appropriate initial treatment for this disease.

Dual Substance Use of Electronic Cigarettes and Alcohol

Electronic cigarettes (ECs) are a modern nicotine delivery system that rapidly grew in widespread use, particularly in younger populations. Given the long history of the comorbidity of alcohol and nicotine use, the rising prevalence of ECs raises the question as to their role in the consumption of alcohol. Of the numerous models of ECs available, JUUL is the most popular. This narrative review aims to determine current trends in literature regarding the relationship between EC and alcohol dual use, as well as hypothesize potential pathogenic tissue damage and summarize areas for future study, including second-hand vapor exposure and calling for standardization among studies. In summary, EC users are more likely to participate in hazardous drinking and are at higher risk for alcohol use disorder (AUD). We surmise the pathogenic damage of dual use may exhibit an additive effect, particularly in pathogen clearance from the lungs, increased inflammation and decreased immune response, physical damage to epithelial cells, and exacerbation of chronic obstructive pulmonary disease (COPD)-like illnesses. A better understanding of pathogenic damages is critical to understand the risks placed on dual users when exposed to respiratory pathogens, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Chronic ethanol consumption compromises neutrophil function in acute pulmonary Aspergillus fumigatus infection

Chronic ethanol consumption is a leading cause of mortality worldwide, with higher risks to develop pulmonary infections, including Aspergillus infections. Mechanisms underlying increased susceptibility to infections are poorly understood. Chronic ethanol consumption induced increased mortality rates, higher Aspergillus fumigatus burden and reduced neutrophil recruitment into the airways. Intravital microscopy showed decrease in leukocyte adhesion and rolling after ethanol consumption. Moreover, downregulated neutrophil activation and increased levels of serum CXCL1 in ethanol-fed mice induced internalization of CXCR2 receptor in circulating neutrophils. Bone marrow-derived neutrophils from ethanol-fed mice showed lower fungal clearance and defective reactive oxygen species production. Taken together, results showed that ethanol affects activation, recruitment, phagocytosis and killing functions of neutrophils, causing susceptibility to pulmonary A. fumigatus infection. This study establishes a new paradigm in innate immune response in chronic ethanol consumers.

Alcoholism is a chronic disease that has many damaging effects on the body. Over long periods, excessive alcohol intake weakens the immune system, putting consumers at increased risk of getting lung infections such as pneumonia.

Some forms of pneumonia can be caused by the fungus Aspergillus fumigatus. This microbe does not tend to be a problem for healthy individuals, but it can be fatal for those with impaired immune systems. Here, Malacco et al. wanted to find out why excessive alcohol consumers are more prone to pneumonia.

To test this, the researchers used two groups of mice that were either fed plain water or water containing ethanol. After 12 weeks, both groups were infected with Aspergillus fumigatus. The results showed that alcohol-fed mice were more susceptible to the infection caused by strong inflammation of the lungs.

Normally, the immune system confronts a lung infection by activating a group of defense cells called neutrophils, which travel through the blood system to the infection site. Once in the right spot, neutrophils get to work by releasing toxins that kill the fungus. Malacco et al. discovered that after chronic alcohol consumption, neutrophils were less reactive to inflammatory signals and less likely to reach the lungs. They were also less effective in dealing with the infection. Neutrophil released fewer toxins and were thus less able to kill the microbial cells.

These findings demonstrate for the first time how alcohol can affect immune cells during infection and pave the way for new possibilities to prevent fatal lung infections in excessive alcohol consumers. A next step would be to identify how alcohol acts on other processes in the body and to find a way to modulate or even revert the changes it causes.

The Contribution of Genetic Variation of Streptococcus pneumoniae to the Clinical Manifestation of Invasive Pneumococcal Disease

Background

Different clinical manifestations of invasive pneumococcal disease (IPD) have thus far mainly been explained by patient characteristics. Here we studied the contribution of pneumococcal genetic variation to IPD phenotype.

Methods

The index cohort consisted of 349 patients admitted to 2 Dutch hospitals between 2000-2011 with pneumococcal bacteremia. We performed genome-wide association studies to identify pneumococcal lineages, genes, and allelic variants associated with 23 clinical IPD phenotypes. The identified associations were validated in a nationwide (n = 482) and a post-pneumococcal vaccination cohort (n = 121). The contribution of confirmed pneumococcal genotypes to the clinical IPD phenotype, relative to known clinical predictors, was tested by regression analysis.

Results

Among IPD patients, the presence of pneumococcal gene slaA was a nationwide confirmed independent predictor of meningitis (odds ratio [OR], 10.5; P = .001), as was sequence cluster 9 (serotype 7F: OR, 3.68; P = .057). A set of 4 pneumococcal genes co-located on a prophage was a confirmed independent predictor of 30-day mortality (OR, 3.4; P = .003). We could detect the pneumococcal variants of concern in these patients' blood samples.

Conclusions

In this study, knowledge of pneumococcal genotypic variants improved the clinical risk assessment for detrimental manifestations of IPD. This provides us with novel opportunities to target, anticipate, or avert the pathogenic effects related to particular pneumococcal variants, and indicates that information on pneumococcal genotype is important for the diagnostic and treatment strategy in IPD. Ongoing surveillance is warranted to monitor the clinical value of information on pneumococcal variants in dynamic microbial and susceptible host populations.

Structural, Biosynthetic, and Serological Cross-Reactive Elucidation of Capsular Polysaccharides from Streptococcus pneumoniae Serogroup 16

Capsular polysaccharides (CPS) are crucial virulence factors of Streptococcus pneumoniae The previously unknown CPS structures of the pneumococcal serogroup 16 (serotypes 16F and 16A) were thoroughly elucidated by nuclear magnetic resonance (NMR) spectroscopy and verified by chemical analysis. The following repeat unit structures were determined: 16F, -3)-α-l-Rhap-[4-P-1-Gro]-(1-3)-α-d-Glcp-[(6-P-1)-Gro]-(1-3)-β-l-Rhap-[2-OAc]-(1-4)-β-d-Glcp-(1-; 16A, -3)-β-d-Galf-[2-OAc (70%)]-(1-3)-α-l-Rhap-(1-2)-α-l-Rhap-(1-3)-α-d-Galp-[(6-P-1)-Gro]-(1-3)-β-d-Galp-(1-4)-β-d-Glcp-(1- (OAc, O-acetyl substitution; P-1-Gro, glycerol-1-phosphate substitution) A further analysis of CPS biosynthesis of serotypes 16F and 16A, in conjunction with published cps gene bioinformatics analysis and structures of related serotypes, revealed presumable specific function of glycosyltransferase, acetyltransferase, phosphotransferase, and polymerase. The functions of glycosyltransferases WcxN and WcxT were proposed for the first time, and they were assigned to catalyze linkage of α-l-Rhap-(1-3)-α-d-Glcp and α-l-Rhap-(1-2)-α-l-Rhap, respectively. Furthermore, since serotype 16F was genetically close to serogroup 28, cross-reactions between serogroup 16 and serogroup 28 were studied using diagnostic antisera, which provided further understanding of antigenic properties of CPS and diagnostic antisera. Interestingly, serotype 16F cross-reacted with factor antisera 28b and 11c. Meanwhile, serotype 16A cross-reacted with factor antiserum 11c.IMPORTANCE The vaccine pressure against Streptococcus pneumoniae could result in a change of prevalence in carriage and invasive serotypes. As such, it is necessary to monitor the distribution to achieve successful vaccination of the population, and similarly, it is important to increase the knowledge of even the currently less prevalent serotypes. The CPS are vital for the virulence of the pathogen, and antigenic properties of CPS are based on the structure. Consequently, a better understanding of the structure, biosynthesis, and serology of the capsular polysaccharides can be of great importance toward developing future diagnostic tools and vaccines.

Self-reported alcohol use in the cystic fibrosis community

INTRODUCTION

Excessive alcohol use (EAU), a harmful pattern of drinking that includes binge drinking and heavy use, occurs in 25% (binge) and 6% (heavy use) of the US population, respectively. Little is known about alcohol use in individuals with cystic fibrosis (CF). The objective of this investigation is to examine alcohol consumption patterns in individuals with CF using a health survey administered from a social media platform.

METHODS

Individuals with CF, 18 years of age or older, were recruited for participation through social media and internet-based platforms.

RESULTS

1135 individuals initially participated in the survey and 84% (n = 952) were eligible and completed the survey. Of the respondents, 77% (n = 729) currently consume alcohol, 18% (n = 171) formerly consumed alcohol, and 5% (n = 52) never consumed alcohol. Amongst the people with CF who currently consume alcohol, 54% (N = 391) met criteria for EAU. Thirty percent of current drinkers experienced symptoms of harmful alcohol use. Of those who met criteria for EAU, 7% wore oxygen, 6% had a lung transplant, 10% had liver disease and 32% had diabetes. Those with EAU reported more hospitalizations than those without EAU [244 (62%) vs 182 (54%), p = .034]. Characteristics associated with EAU after multivariable adjustment included younger age, unmarried status, male gender and younger age at initiation of drinking.

CONCLUSION

EAU is occurring at a much higher proportion in individuals with CF. A substantial percentage of CF individuals with EAU also have medical co-morbidities. Screening, brief intervention, and referral to treatment for EAU in CF clinics is warranted.

Analysis of Streptococcus pneumoniae using Fourier-transformed infrared spectroscopy allows prediction of capsular serotype

Determination of the capsule type of clinical isolates of Streptococcus pneumoniae is a prerequisite for epidemiological studies and further vaccine development. The Quellung reaction for serotyping is expensive and mostly done in reference centres. We wanted to evaluate whether Fourier-transformed infrared (FT-IR) spectroscopy is suitable for capsular type analysis and prediction of pneumococcal serotypes. We used the IR-Biotyper™ (Bruker) to create a database containing the spectra of 120 strains from invasive disease. The strains covered the 24 vaccine serotypes contained in the 13-valent conjugate vaccine (PCV13) and the 23-valent polysaccharide vaccine (PSV23). Hierarchical clustering analysis was performed. Finally, two different classification sets were created (PCV13 and PSV23). They were used to predict the serotype of 168 different challenge strains (invasive and non-invasive disease) covering 48 different serotypes (vaccine and non-vaccine types). FT-IR spectra from pneumococci (1300–800 cm⁻¹) clustered along their serotype as determined by the Quellung reaction (120 strains, 24 different serotypes). Strains with unknown serotype fell within the cluster of the correct serotype, as long as the latter was represented in the database (168 strains, 48 different serotypes). Concordance between the Quellung reaction and FT-IR spectroscopy was excellent (kappa ≥ 0.75). FT-IR spectroscopy is a fast and cost-effective method to predict the capsular serotype of pneumococci.

A Systematic Review and Metaanalysis of Antirheumatic Drugs and Vaccine Immunogenicity in Rheumatoid Arthritis

OBJECTIVE

Vaccination is a key strategy to reduce infection risk in patients with rheumatoid arthritis (RA) and is advocated in internationally recognized rheumatology society guidelines. The aim was to evaluate to the effect of antirheumatic drugs on influenza and pneumococcal vaccine immunogenicity.

METHODS

We conducted a systematic literature review and metaanalysis comparing the humoral response to influenza (pandemic and seasonal trivalent subunit vaccines) and pneumococcal (23-valent pneumococcal polysaccharide vaccine, 7- and 13-valent pneumococcal conjugated vaccines) vaccination in adult patients with RA treated with antirheumatic drugs. Vaccine immunogenicity was assessed by seroprotection rates measured 3 to 6 weeks postimmunization. Risk ratios (RR) and 95% CI were pooled.

RESULTS

Nine studies were included in the metaanalysis (7 studies investigating antirheumatic drug exposures and influenza humoral response, 2 studies investigating pneumococcal vaccine response). Influenza vaccine responses to all subunit strains (H1N1, H3N2, B strain) were preserved with methotrexate (MTX) and tumor necrosis factor inhibitor (TNFi) drug exposure. MTX but not TNFi drug exposure was associated with reduced 6B and 23F serotype pneumococcal vaccine response (RR 0.42, 95% CI 0.28-0.63 vs RR 0.98, 95% CI 0.58-1.67); however, limited data were available to draw any firm conclusions. Combination of MTX with tocilizumab or tofacitinib was associated with reduced pneumococcal and influenza vaccine responses.

CONCLUSION

Antirheumatic drugs may limit humoral responses to vaccination as evidenced by pneumococcal responses with MTX exposure; however, they are safe and should not preclude immunization against vaccine-preventable disease. Vaccination should be considered in all patients with RA and encouraged as part of routine care. (Systematic review registration number: PROSPERO 2016: CRD42016048093.).

Long-term mortality after IPD and bacteremic versus non-bacteremic pneumococcal pneumonia

BACKGROUND

Short-term mortality after invasive pneumococcal disease (IPD) and pneumococcal pneumonia is high but data on long-term mortality (including the comparison between bacteremic and non-invasive/non-bacteremic pneumococcal pneumonia) within the first years after diagnosis are scarce.

METHODS

Adult patients with 'non-pneumonia' IPD and 'invasive pneumonia' (from 2004 to 2012) and with 'bacteremic' vs 'non-invasive/non-bacteremic (NI/NB)' pneumococcal pneumonia (from 2008 to 2012) diagnosed by negative blood culture but a positive urinary antigen test (UAT) were identified in a Dutch hospital. Mortality of patients up to 10years after diagnosis was compared with age- and sex-matched life-expectancy data of the general population. Multivariable Cox regression analysis was used to study predictors for mortality in invasive pneumonia patients and to adjust for confounders comparing mortality between bacteremic and NI/NB/UAT-positive pneumonia patients.

RESULTS

Of 228 invasive pneumonia patients 17% died within 30days and in 30-day survivors cumulative long-term mortality at 1 and 5years were 16% and 39% as compared with 3% and 15% in age- and sex-matched persons. High mortality was largely dependent on pre-existent comorbidities. In invasive pneumonia patients who survived the first 30days, age, male gender, chronic cardiovascular disease, malignancy and PCV7 serotype disease were independent predictors for higher long-term mortality. For bacteremic pneumonia patients (n=128) 30-day mortality was 16% and almost similar to 14% in NI/NB/UAT-positive pneumococcal pneumonia patients (n=170). In 30-day survivors of bacteremic pneumonia (n=108, median age 66years), cumulative mortality at 1 and 3years were 13% and 29% as compared with 18% and 40% in NI/NB/UAT-positive pneumococcal pneumonia patients (n=146, median age 67years) without a significant difference in mortality.

CONCLUSIONS

Approximately 40% of all patients, who survived the first 30days after presentation with non-pneumonia IPD and pneumococcal pneumonia died within the following 5years. High long-term mortality was largely dependent on pre-existent comorbidity.

Influenza A Virus Infection Predisposes Hosts to Secondary Infection with Different Streptococcus pneumoniae Serotypes with Similar Outcome but Serotype-Specific Manifestation

Influenza A virus (IAV) and Streptococcus pneumoniae are major causes of respiratory tract infections, particularly during coinfection. The synergism between these two pathogens is characterized by a complex network of dysregulated immune responses, some of which last until recovery following IAV infection. Despite the high serotype diversity of S. pneumoniae and the serotype replacement observed since the introduction of conjugate vaccines, little is known about pneumococcal strain dependency in the enhanced susceptibility to severe secondary S. pneumoniae infection following IAV infection. Thus, we studied how preinfection with IAV alters host susceptibility to different S. pneumoniae strains with various degrees of invasiveness using a highly invasive serotype 4 strain, an invasive serotype 7F strain, and a carrier serotype 19F strain. A murine model of pneumococcal coinfection during the acute phase of IAV infection showed a significantly increased degree of pneumonia and mortality for all tested pneumococcal strains at otherwise sublethal doses. The incidence and kinetics of systemic dissemination, however, remained bacterial strain dependent. Furthermore, we observed strain-specific alterations in the pulmonary levels of alveolar macrophages, neutrophils, and inflammatory mediators ultimately affecting immunopathology. During the recovery phase following IAV infection, bacterial growth in the lungs and systemic dissemination were enhanced in a strain-dependent manner. Altogether, this study shows that acute IAV infection predisposes the host to lethal S. pneumoniae infection irrespective of the pneumococcal serotype, while the long-lasting synergism between IAV and S. pneumoniae is bacterial strain dependent. These results hold implications for developing tailored therapeutic treatment regimens for dual infections during future IAV outbreaks.

Pneumococcal vaccination

PURPOSE OF REVIEW

Pneumococcal diseases (invasive diseases, pneumonia, otitis media, and sinusitis) are among the most frequent preventable infectious diseases carrying a very high morbidity and case fatality rate worldwide. Pneumococcal vaccination is a key element to reduce the global burden of the disease in children and adult population. Our aim is to discuss current knowledge of the epidemiology of pneumococcal disease and pneumococcal vaccines.

RECENT FINDINGS

After the introduction of conjugate vaccines (PCV7 and PCV13), rates of pneumococcal diseases because of vaccine serotypes have decreased considerably among children in the vaccine target and among nonvaccinated children and adults. Results of the Community-Acquired Pneumonia Immunization Trial in Adults demonstrated 45.6% efficacy of PCV13 against the first episode of pneumonia, 45% against first-episode nonbacteremic pneumococcal pneumonia, and 75% against the first episode of invasive pneumococcal diseases in adults older than 65 years. Recommendations for pneumococcal vaccination have changed recently in both the United States and Europe.

SUMMARY

The changing epidemiology of pneumococcal diseases should be closely investigated to assess the effectiveness and the usefulness of the current vaccination policies, and to identify future directions for preventing pneumococcal infections.

The Roles of the Charlson Comorbidity Index and Time to First Antibiotic Dose as Predictors of Outcome in Pneumococcal Community-Acquired Pneumonia

PURPOSE

In this retrospective study, we aimed to investigate the role of comorbidities using the Charlson comorbidity index (CCI) and time to first antibiotic dose (TFAD) in patients with pneumococcal community-acquired pneumonia (PCAP).

METHODS

All consecutive ER admissions with PCAP who were hospitalized in the University Hospital, Zurich between 2006 and 2012 were included. The primary outcome was to determine possible determinants of all-cause in-hospital mortality (ACIHM). The second endpoint was to detect risk factors for adverse events (AEs) and determinants of length of stay (LOS).

RESULTS

108 subjects (mean age 57.6 years) were included. The median (IQR) CCI was 4 (1, 8). The median (IQR) TFAD was 210 (150, 280) min. ACIHM was 6.5 % (7/108), and median (IQR) LOS was 9 (6, 14) days. PCAP-related AEs were observed in 57 cases (52.8 %). In the multivariable analysis, neither CCI nor TFAD was associated with the outcome measures. Pneumonia severity index (PSI) was the only statistically significant predictor of ACIHM (HR 1.31/10 point increase, 95 % CI 1.12-1.53, p = 0.001) and AE rate (OR 1.31, 95 % CI 1.15-1.50, p < 0.001).

CONCLUSIONS

In this study including comparatively young patients with rather mild disease severity, we found no strong evidence supporting that CCI or TFAD influenced short-term outcome measures of PCAP. Yet, pneumonia severity appears to be the most important factor for the outcome.

Clinical and microbiological implications of invasive pneumococcal disease in hospitalized patients (1998-2013)

INTRODUCTION

Infections caused by Streptococcus pneumoniae (pneumococcus) still represent a challenge for health systems around the world.

OBJECTIVE

The objective of this study was to assess microbiological and clinical aspects in hospitalized patients with invasive pneumococcus disease between 1998 and 2013.

MATERIALS AND METHODS

This was a retrospective study that analyzed the results of pneumococcus identification, serotyping, and susceptibility testing found in the Adolfo Lutz Institute databank. Personal variables, medical history and clinical outcome of patients admitted with invasive pneumococcal disease were analyzed. These were obtained from records of a public teaching hospital - Hospital das Clínicas Faculdade de Medicina Ribeirão Preto.

RESULTS

The sample comprised 332 patients. Patient age ranged from less than one month to 89 years old (mean 20.3 years) and the sample was predominately male. Pneumonia (67.8%) was the most common disease, accounting for 18.2% of deaths. Serotypes 14, 1, 3, 9V, 6B, 6A, 23F, 19A, 18C, 19F, 12F, and 4 were the most common (75.3%). Most patients, or 67.5%, were cured without any complication (success), 6.9% had some type of sequela (failure), and 25.6% died (failure). In the case of deaths due to meningitis, strains of fully penicillin resistant pneumococcus were isolated. Furthermore, 68.2% of patients who died presented some type of comorbidity. The 60 and older age group presented the most significant association (Odds Ratio=4.2), with outcome failure regardless of the presence of comorbidity. Serotype 18C was the most significant risk factor both in raw analysis (Odds Ratio=3.8) and when adjusted for comorbidity (Odds Ratio=5.0) or age (Odds Ratio=5.4). The same occurred with serotype 12F (respectively, Odds Ratio=5.1, Odds Ratio=5.0, and Odds Ratio=4.7) CONCLUSION: The present findings highlight the importance of IPD among young adults and older adults. In the era of conjugate vaccines, monitoring serotypes in different age groups is essential to assess the impact and adequacy of immunization.

The potential role of 13-valent pneumococcal conjugate vaccine in preventing respiratory complications in bacteraemic pneumococcal community-acquired pneumonia

INTRODUCTION

Pneumococcal 13-valent vaccine (PCV-13) has a potential role in preventing bacteraemic pneumococcal pneumonia and its complications, but little is known about its ability to specifically prevent respiratory complications. Our aim were to analyse the pneumococcal serotypes associated with the development of respiratory complications and the potential role of PCV-13 in preventing respiratory complications in bacteraemic pneumococcal pneumonia.

MATERIAL AND METHODS

We analysed demographic characteristics, comorbidities, antibiotic resistances and the outcomes of a cohort of 65 vaccine-naïve bacteraemic pneumococcal pneumonias, stratified by the pneumococcal serotypes included in PCV13 vs. those not included. Complications were clustered as follows: respiratory complications (hypoxemic respiratory failure; mechanical ventilation), systemic complications (septic shock; multiorgan failure), suppurative complications (empyema; pleural effusion; lung abscess).

RESULTS

From a population of 65 CAP-SP, 47.7% of the isolates belonged to PCV-13 serotypes group. No differences in comorbidities or clinical manifestations were found between groups. With regard to biochemical parameters, we found more profound hypoxemia levels in PCV-13 serotypes group comparing to non-vaccine group [PaO2/FiO2 209 (63) vs. 268 (57); p=0.007]. Global complications were identified in 69.2% (45 patients), and the most frequent were respiratory complications, found in 47.7%. Respiratory complications were detected more frequently in PCV-13 groups compared to non-vaccine groups (61.3% vs. 35.3%; p=0.036). Overall 30-day mortality was 30.8%. Mortality was similar between both groups (25.8% vs. 35.3%; p=0.408).

CONCLUSIONS

Pneumococcal 13-valent conjugate vaccine includes the serotypes which cause more respiratory complications in our series; these serotypes were not associated with higher mortality in our series. PCV-13 may have a potential role in preventing respiratory complications due to bacteraemic pneumonoccal pneumonia.

The host immune dynamics of pneumococcal colonization: implications for novel vaccine development

The human nasopharynx (NP) microbiota is complex and diverse and Streptococcus pneumoniae (pneumococcus) is a frequent member. In the first few years of life, children experience maturation of their immune system thereby conferring homeostatic balance in which pneumococci are typically rendered as harmless colonizers in the upper respiratory environment. Pneumococcal carriage declines in many children before they acquire capsular-specific antibodies, suggesting a capsule antibody-independent mechanism of natural protection against pneumococcal carriage in early childhood. A child's immune system in the first few years of life is Th2-skewed so as to avoid inflammation-induced immunopathology. Understanding Th1/Th2 and Th17 ontogeny in early life and how adjuvant vaccine formulations shift the balance of T helper-cell differentiation, may facilitate the development of new protein-based pneumococcal vaccines. This article will discuss the immune dynamics of pneumococcal colonization in infants. The discussion aims to benefit the design and improvement of protein subunit-based next-generation pneumococcal vaccines.

First report of an outbreak of pneumonia caused by Streptococcus pneumoniae serotype 6A

Five patients in a geropsychiatric unit of a psychiatric hospital became abruptly ill with pneumonia caused by Streptococcus pneumoniae serotype 6A. Four other residents were colonized with the same serotype, which has previously not been reported in association with pneumonia outbreaks. Furthermore, serotype 6A is not included in all vaccine types, which may be important for the choice of vaccine in some settings. All isolates showed identical pulsed-field gel electrophoresis restriction patterns.

Risk factors for death from invasive pneumococcal disease, Europe, 2010

Risk varies by Streptococcus pneumoniae serotype.

We studied the possible association between patient age and sex, clinical presentation, Streptococcus pneumoniae serotype, antimicrobial resistance, and death in invasive pneumococcal disease cases reported by 17 European countries during 2010. The study sample comprised 2,921 patients, of whom 56.8% were men and 38.2% were >65 years of age. Meningitis occurred in 18.5% of cases. Death was reported in 264 (9.0%) cases. Older age, meningitis, and nonsusceptibility to penicillin were significantly associated with death. Non–pneumococcal conjugate vaccine (PCV) serotypes among children <5 years of age and 7-valent PCV serotypes among persons 5–64 years of age were associated with increased risk for death; among adults >65 years of age, risk did not differ by serotype. These findings highlight differences in case-fatality rates between serotypes and age; thus, continued epidemiologic surveillance across all ages is crucial to monitor the long-term effects of PCVs.

Serotype 1 and 8 Pneumococci Evade Sensing by Inflammasomes in Human Lung Tissue

Streptococcus pneumoniae is a major cause of pneumonia, sepsis and meningitis. The pore-forming toxin pneumolysin is a key virulence factor of S. pneumoniae, which can be sensed by the NLRP3 inflammasome. Among the over 90 serotypes, serotype 1 pneumococci (particularly MLST306) have emerged across the globe as a major cause of invasive disease. The cause for its particularity is, however, incompletely understood. We therefore examined pneumococcal infection in human cells and a human lung organ culture system mimicking infection of the lower respiratory tract. We demonstrate that different pneumococcal serotypes differentially activate inflammasome-dependent IL-1β production in human lung tissue and cells. Whereas serotype 2, 3, 6B, 9N pneumococci expressing fully haemolytic pneumolysins activate NLRP3 inflammasome-dependent responses, serotype 1 and 8 strains expressing non-haemolytic toxins are poor activators of IL-1β production. Accordingly, purified haemolytic pneumolysin but not serotype 1-associated non-haemolytic toxin activates strong IL-1β production in human lungs. Our data suggest that the evasion of inflammasome-dependent innate immune responses by serotype 1 pneumococci might contribute to their ability to cause invasive diseases in humans.

[Influence of age on the clinical manifestations of invasive pneumococcal disease and antibiotic resistance rates]

BACKGROUND AND OBJECTIVE

Invasive pneumococcal disease (IPD) shows different epidemiological characteristics depending on age and pneumococcus serotype. The aims of the work were to analyze the clinical manifestations and mortality associated with IPD, the serotype isolated and the antibiotic resistance rates in different age groups.

PATIENTS AND METHOD

Retrospectively, 141 patients with IPD diagnosed between 2002 and 2008 were studied. Patients were classified in 4 age groups: ≤ 2 year-old, 3-14 year-old, 15-64 year-old and ≥ 65 year-old.

RESULTS

Pneumonia was the most common manifestation in all age groups (71%). Pneumococcal meningitis was more prevalent in patients ≤ 2 year-old (28 vs. 9%, P=.054) and empyema was more frequent in those between 3-14 year-old (31 vs. 5%, P<.001). Mortality was associated with age ≥ 65 year-old (odds ratio [OR] 7, 95% confidence interval [95% CI] 1.9-28.9), primary bacteremia (OR 7, 95% CI 1.9-28.9) and orotracheal intubation (OR 9, 95% CI 1.9-41.1). The more prevalent serotypes among patients ≤ 2 year-old were 14, 19A and 19F. The serotype 1 was most common in patients between 3-14 year-old and serotype 3 in those ≥ 65 year-old. A higher rate of non-susceptible penicillin strains was observed in pediatric population (42 vs. 19%, P=.007).

CONCLUSIONS

Age was related to the clinical manifestations, mortality and antibiotic resistance rates. Primary bacteremia was one of the risk factors of mortality.

Decrease in mortality in severe community-acquired pneumococcal pneumonia: impact of improving antibiotic strategies (2000-2013)

OBJECTIVE

The objective of the present study was to compare antibiotic prescribing practices and survival in the ICU for patients with pneumococcal severe community-acquired pneumonia (SCAP) between 2000 and 2013.

METHODS

This was a matched case-control study of two prospectively recorded cohorts in Europe. Eighty patients from the Community-Acquired Pneumonia en la Unidad de Cuidados Intensivos (CAPUCI) II study (case group) were matched with 80 patients from CAPUCI I (control group) based on the following: shock at admission, need of mechanical ventilation, COPD, immunosuppression, and age.

RESULTS

Demographic data were comparable in the two groups. Combined antibiotic therapy increased from 66.2% to 87.5% (P < .01), and the percentage of patients receiving the first dose of antibiotic within 3 h increased from 27.5% to 70.0% (P < .01). ICU mortality was significantly lower (OR, 0.82; 95% CI, 0.68-0.98) in cases, both in the whole population and in the subgroups of patients with shock (OR, 0.67; 95% CI, 0.50-0.89) or receiving mechanical ventilation (OR, 0.73; 95% CI, 0.55-0.96). In the multivariate analysis, ICU mortality increased in patients requiring mechanical ventilation (OR, 5.23; 95% CI, 1.60-17.17) and decreased in patients receiving early antibiotic treatment (OR, 0.36; 95% CI, 0.15-0.87) and combined therapy (OR, 0.19; 95% CI, 0.07-0.51).

CONCLUSIONS

In pneumococcal SCAP, early antibiotic prescription and use of combination therapy increased. Both were associated with improved survival.

Effects of 7-valent pneumococcal conjugate 1 vaccine on the severity of adult 2 bacteremic pneumococcal pneumonia

PURPOSE

The introduction of a 7-valent conjugate pneumococcal vaccine (PCV7) in children largely affected the prevalence of adult pneumococcal pneumonia. In this study we investigated whether the clinical severity of adult bacteremic pneumococcal pneumonia has also altered following the introduction of pediatric PCV7 vaccination.

METHODS

Adults hospitalized with bacteremic pneumococcal pneumonia between 2001 and June 2011 at two Dutch hospitals were included retrospectively. Clinical data on patient characteristics, comorbidities and severity of disease were obtained and pneumococcal serotypes were determined.

RESULTS

Among 343 patients investigated, those infected with PCV7 serotypes had a higher PSI score (p=0.0072) and mortality rate (p=0.0083) compared with the remainder of the cohort. Since the introduction of PCV7 the proportion of pneumococcal pneumonias caused by serotypes 1 and 7F (p-values 0.037 and 0.025) increased, as well as the rate of pleural effusion and empyema (p-values 0.011 and 0.049). Whilst de proportion of adults infected with PCV7 serotypes decreased after the introduction of PCV7 (p=0.015), PSI scores in these patients remained higher (p=0.030), although mortality rates between PCV7 and non PCV7 types equalized. After the introduction of PCV7 a marked shortening in hospital stay was observed only among patients infected with non PCV7 serotypes (p=0.019).

CONCLUSIONS

The introduction of pediatric PCV7 vaccination was accompanied by subtle changes in clinical severity of adult bacteremic pneumococcal pneumonia. Expansion of serotypes covered by pneumococcal vaccination may again influence the clinical presentation of disease.

The role of vaccination in preventing pneumococcal disease in adults

Pneumococcal infections, including pneumonia and invasive disease, are major sources of morbidity and mortality worldwide. Prevention of the first acquisition of Streptococcus pneumoniae through the use of vaccines represents an effective method to reduce the burden of the disease in both children and adults. Two vaccines are currently available in adults: a pneumococcal polysaccharide vaccine (PPV23) that includes 23 purified capsular polysaccharide antigens and a pneumococcal protein-conjugate vaccine (PCV13) that includes capsular polysaccharide antigens covalently linked to a non-toxic protein. The PPV23 induces a humoral immune response and since it has been licensed has been the subject of debates and controversies. Numerous studies and meta-analyses have shown that PPV23 protects against invasive pneumococcal disease, although there are conflicting data regarding its efficacy for the prevention of pneumonia. Vaccination with PCV13 stimulates good antibody responses as well as mucosal immunity and suppresses colonization. A conjugate vaccine can be expected to have benefits over a polysaccharide vaccine because of the characteristics of a T-cell-dependent response in terms of affinity, maturation of antibodies with repeated exposure, induction of immunological memory and long-lasting immunity. PCV13 has demonstrated all of these characteristics in children and fundamental differences in adults are not expected. The efficacy in adults is currently being investigated and results will be available soon.

Differences in serious clinical outcomes of infection caused by specific pneumococcal serotypes among adults

BACKGROUND

Infections due to Streptococcus pneumoniae serotypes differ in clinical manifestations among adults, varying in propensity for severity, invasiveness, and lethality. To characterize differences in serious outcomes between pneumococcal serotypes, we systematically reviewed the literature.

METHODS

After distilling 676 hits to 28 relevant articles, statistically significant differences in individual serotypes associated with serious clinical outcomes were assessed. Serotypes associated with elevated risk of serious clinical outcomes were evaluated in terms of serotypes included in licensed adult pneumococcal vaccines (i.e., 23-valent pneumococcal polysaccharide vaccine (PPSV23) and 13-valent pneumococcal conjugate vaccine (PCV13)). Repeated findings were considered a measure of robustness.

RESULTS

Among adult studies evaluating serious clinical outcomes, the following serotypes were associated with elevated risk: Empyema (serotypes 1, 3, 5, 7F, 8, 19A), necrotizing pneumonia (serotype 3), septic shock (serotypes 3, 19A), meningitis (repeatedly serotypes 10A, 15B, 19F, 23F), reduced quality-adjusted life years (QALYs, serotypes 15B, 3, 10A, 9N, 19F, 11A, 31), and increased case-fatality rates (repeatedly serotypes 3, 6B, 9N, 11A, 16F, 19F, 19A).

CONCLUSION

Both vaccine formulations include multiple pneumococcal serotypes associated with increased risk for serious clinical outcomes. Three studies found elevated risk from serotype 6A (unique to PCV13). Fourteen studies found elevated risk from nine serotypes unique to PPSV23 (repeatedly: case-fatality-11A & 9N, meningitis-10A & 15B). Seven studies found elevated risk from serotypes not represented in either vaccine formulation (notably 16F). The pneumococcal serotypes repeatedly associated with elevated risk of serious outcomes in adults are an important consideration for vaccine policy making.

Pneumococcal empyema and complicated pneumonias: global trends in incidence, prevalence, and serotype epidemiology

This review evaluates the serotype epidemiology of complicated pneumococcal pneumonia (CPP) during the period 1990–2012. PubMed and EMBASE were searched using the terms “empyema”, “complicated pneumonia”, “pleural infection”, “necrotizing pneumonia”, “pleural effusion”, “parapneumonic effusion”, “pneumatocele”, or “lung abscess”; “pneumococcal” or “Streptococcus pneumoniae”; and “serotype” for studies on the epidemiology of complicated pneumonias published from January 1, 1990 to October 1, 2013. Studies with data on incidence and serotypes were included; reviews, case reports, and conference abstracts were excluded. Of 152 papers, 84 fitted the inclusion criteria. A few pneumococcal serotypes were predominant causes of CPP, particularly serotypes 1, 19A, 3, 14, and 7F. CPP was a more common manifestation of pneumococcal disease among older (>2 years old) than younger children. The data support increases in both reported incidence rates and proportions of CPP in children and adults during the period 1990–2012; specific increases varied by geographic region. The proportions of serotype 3 and, particularly in Asia, serotype 19A CPP have increased, whereas most studies show declines in serotype 14. Serotype 1 has been a predominant cause of CPP since 1990, while antibiotic resistance was infrequent among serotype 1 isolates. The reported incidence and proportions of CPP among pneumonia cases steadily increased from 1990 to 2012. Several factors might account for these increases, including enhanced disease detection due to a higher index of suspicion, more sophisticated diagnostic assays, and changes in the prevalence of serotypes with capacity to invade the pleural space that were not targeted by the 7-valent pneumococcal conjugate vaccine (PCV7).

Clinical features of adults with seven-valent-conjugated-vaccine-serotype pneumococcal pneumonia

BACKGROUND

Despite the reduction in adult invasive pneumococcal disease through 'herd protection' consequent to the introduction of childhood pneumococcal conjugate vaccination (PCV), a significant proportion of adults continue to develop pneumococcal pneumonia caused by one of the seven serotypes included in the seven-valent conjugated pneumococcal vaccine (PCV7). The clinical features and outcomes of these adults have not been previously reported.

METHODS

Adults recruited over a three year period to a large prospective cohort study of community acquired pneumonia (CAP) were investigated for pneumococcal serotypes using a validated multiplex immunoassay (Bio-plex). The baseline characteristics and outcomes of adults with PCV7-serotype CAP in comparison to those with non-PCV7-serotype CAP were established.

RESULTS

Pneumococcal aetiology was identified in 415 of 1166 (35.6%) individuals, and a serotype determined in 287 (69.2%). Following exclusion of three individuals with both a PCV7 and non-PCV7 serotype, 77 of the remaining 284 (27.1%) adults had CAP due to PCV7 serotypes. Adults with PCV7-serotype CAP were older (median years (inter-quartile range) 73.3 (60.8-84.4) versus 65.0 (46.1-78.0); p=0.001) and were more likely to have a World Health Organisation performance status ≥1 (odds ratio (OR) 2.05, 95% confidence interval (CI) 1.21-3.50).The presence of stroke (adjusted OR 2.84, 95% CI 1.36-5.95) and dementia (adjusted OR 3.55, 95% CI 1.26-9.94) as underlying co-morbid illnesses were independently associated with PCV7-serotype CAP; 30-day mortality was significantly greater in adults with PCV7-serotype CAP (adjusted OR 4.38, 95% CI 1.85-10.34).

CONCLUSION

A significant proportion of adults continue to develop PCV7-serotype CAP in the era of childhood pneumococcal conjugate vaccination. These adults are more likely to have stroke and dementia as underlying co-morbid illnesses, and have a higher 30-day mortality. A combination of pneumococcal transmission factors, host factors and pneumococcal serotype specific characteristics are likely to explain these findings.

Pneumococcal serotypes before and after introduction of conjugate vaccines, United States, 1999-2011(1.)

Serotyping data for pneumococci causing invasive and noninvasive disease in 2008-2009 and 2010-2011 from >43 US centers were compared with data from preconjugate vaccine (1999-2000) and postconjugate vaccine (2004-2005) periods. Prevalence of 7-valent pneumococcal conjugate vaccine serotypes decreased from 64% of invasive and 50% of noninvasive isolates in 1999-2000 to 3.8% and 4.2%, respectively, in 2010-2011. Increases in serotype 19A stopped after introduction of 13-valent pneumococcal vaccine (PCV13) in 2010. Prevalences of other predominant serotypes included in or related to PCV13 (3, 6C, 7F) also remained similar for 2008-2009 and 2010-2011. The only major serotype that increased from 2008-2009 to 2010-2011 was nonvaccine serotype 35B. These data show that introduction of the 7-valent vaccine has dramatically decreased prevalence of its serotypes and that addition of serotypes in PCV13 could provide coverage of 39% of isolates that continue to cause disease.

The Epidemiology of Alcohol Abuse and Pneumonia

The association between alcohol abuse and pneumonia has been recognized for more than two centuries and represents an enormous health burden worldwide. The first published notation of alcohol as a clinical risk factor for the development of pneumonia is now over 200 years old, and since then there have been over a 1,000 references in the medical literature confirming these observations. Even in this modern era of medicine pneumonia remains a common infection that afflicts over 450 million persons worldwide annually and causes 7 % of all deaths. When one considers that alcohol is the most commonly abused substance in the world, the enormous excessive burden that alcohol contributes to the morbidity and mortality of pneumonia represents a major public health consideration. In this chapter we review the foundational literature that has chronicled the evolution of our understanding of the association between pneumonia and alcohol abuse over the past century. In addition, we discuss some of the specific pathogens that are particularly associated with serious lung infections in individuals with alcohol use disorders. Finally, we consider some of the specific guidelines for the treatment and prevention of pneumonia in the setting of alcohol abuse.

Treating paediatric community-acquired pneumonia in the era of antimicrobial resistance

Increasing levels of paediatric community-acquired pneumonia (CAP), caused by drug-resistant bacteria and antimicrobial resistance, vary with age and countries and, in some cases, serotypes. When empirical first-line treatment administration fails, paediatricians should consider second-line treatments based on the prevalence of local resistance. A more judicious use of antimicrobial agents is also required.

CONCLUSION

Knowledge of local epidemiology and an appropriate use of antimicrobial drugs are necessary to treat CAP in this era of antimicrobial resistance.

Effects of immunocompromise and comorbidities on pneumococcal serotypes causing invasive respiratory infection in adults: implications for vaccine strategies

BACKGROUND

The 13-valent pneumococcal conjugate vaccine (PCV13) has recently been approved for use in immunocompromised adults. However, it is unclear whether there is an association between specific underlying conditions and infection by individual serotypes. The objective was to determine the prevalence of serotypes covered by PCV13 in a cohort of patients with invasive pneumococcal disease of respiratory origin and to determine whether there are specific risk factors for each serotype.

METHODS

An observational study of adults hospitalized with invasive pneumococcal disease in 2 Spanish hospitals was conducted during the period 1996-2011. A multinomial regression analysis was performed to identify conditions associated with infection by specific serotypes (grouped according their formulation in vaccines and individually).

RESULTS

A total of 1094 patients were enrolled; the infecting serotype was determined in 993. In immunocompromised patients, 64% of infecting serotypes were covered by PCV13. After adjusting for age, smoking, alcohol abuse, and nonimmunocompromising comorbidities, the group of serotypes not included in either PCV13 or PPV23 were more frequently isolated in patients with immunocompromising conditions and cardiopulmonary comorbidities. Regarding individual serotypes, 6A, 23F, 11A, and 33F were isolated more frequently in patients with immunocompromise and specifically in some of their subgroups. The subgroup analysis showed that serotype10A was also associated with HIV infection.

CONCLUSIONS

Specific factors related to immunocompromise seem to determine the appearance of invasive infection by specific pneumococcal serotypes. Although the coverage of serotypes in the 13-valent conjugate pneumococcal vaccine (PCV13) was high, some non-PCV13-emergent serotypes are more prevalent in immunocompromised patients.

Serotype distribution and antibiotic susceptibility of invasive Streptococcus pneumoniae isolates in patients aged 50 years or older in Thailand

As the 13-valent pneumococcal conjugate vaccine (PCV13) has been approved for use in adults aged 50 y and older, we evaluated vaccine-serotype coverage rate in Thai adult patients with invasive pneumococcal infections before the vaccine was widely used. Of the 157 S. pneumoniae isolates from normal sterile sites during January 2005 to September 2012, 150 (95%) from blood, mean patients' age 69.6 (range 50-89) years, the overall serotype coverage by PCV13 was 58%. The vaccine covered 50%, 56%, 59%, and 68% of the invasive isolates from patients aged 50-59, 60-69, 70-79, and ≥80 y, respectively. The most common vaccine serotypes were 6B (17%), 19A (9%), 18C (5%), and 23F (4%). The susceptibility rates of penicillin and ceftriaxone were 95% and 96% for nonmeningitis criteria; and 46% and 92% for meningitis criteria, respectively. The susceptibilities to other antibiotics were: chloramphenicol 76%, clindamycin 80%, erythromycin 57%, levofloxacin 100%, ofloxacin 94%, tetracycline 39%, trimethoprim/sulfamethoxazole 37%, linezolid 99%, and vancomycin 100%, respectively. These data served as a reference for monitoring of vaccine serotype coverage with future increased vaccine utilization.

Compared effectiveness of the 7-valent pneumococcal conjugate vaccine in children with the 13-valent vaccine in adults

13-valent-pneumococcal conjugated vaccine was recently approved in the USA and Europe for adults 50 years of age or more. But this approval was followed by recommendations limiting its use to immunocompromised and asplenic patients. The extension of indications to adults was based on the well-demonstrated clinical effectiveness in infants less than 2 years of age, and on a better immune response either quantitatively or qualitatively with conjugated vaccines compared to the immunogenicity of plain polysaccharide vaccines. Nevertheless, the issue was to know whether results observed with the 7-valent pneumococcal conjugate vaccine in children are reproducible in adults with the 13-valent. The answer was given by comparing the epidemiological and physiopathological data, and the immunological response of the two populations. Very few clinical effectiveness studies in adults are available. We had for aim to assess these various issues in infants and adults. A lot of questions remain, such as the unknown impact of serotype replacement with the 13-valent pneumococcal conjugated vaccine on the clinical epidemiology and emergent Streptococcus pneumoniae pathogenicity, while waiting for the CAPITA study results expected in 2014.

Dynamics of Streptococcus pneumoniae serotypes causing acute otitis media isolated from children with spontaneous middle-ear drainage over a 12-year period (1999-2010) in a region of northern Spain

The aim of this study was to determine the serotype and clonal distribution of pneumococci causing acute otitis media (AOM) and their relationship with recurrences and mixed infections with other microorganisms under the influence of the 7-valent pneumococcal conjugate vaccine (PCV7). To do this, all pneumococcal isolates collected from the spontaneous middle-ear drainage of children <5 years old diagnosed of AOM by their pediatrician or their general practitioner from 1999 to 2010 were phenotypically characterized and the most frequent serotypes were genotyped. In the 12-year study, 818 episodes of pneumococcal AOM were detected, mostly (70.5%) in children younger than 2 years old. In 262 episodes (32%), the pneumococci were isolated with another bacterium, mainly (n = 214) Haemophilus influenzae. Mixed infections were similar in children under or over 2 years old. The most frequent serotypes were 19A (n = 227, 27.8%), 3 (n = 92, 11.2%) and 19F (n = 74, 9%). Serotypes included in the PCV7 sharply decreased from 62.4% in the pre-vaccination (1999–2001) to 2.2% in the late post-vaccination period (2008–2010). Serotype diversity steadily increased after the introduction of the PCV7 but decreased from 2008–2010 due to the predominant role of serotype 19A isolates, mostly ST276 and ST320. The prevalence of serotype 3 doubled from 6.1% (20/326) in 1999–2004 to 14.6% (72/492) in 2005–2010. Relapses mainly occurred in male infants infected with isolates with diminished antimicrobial susceptibility. Reinfections caused by isolates with the same serotype but different genotype were frequent, highlighting the need for genetic studies to differentiate among similar strains. In conclusion, the main change in pneumococcal AOM observed after the introduction of the PCV7 was the sharp decrease in vaccine serotypes. Also notable was the high burden of serotype 19A in total pneumococcal AOM before and especially after the introduction of the PCV7, as well as in relapses and reinfections.

Increased paediatric hospitalizations for empyema in Australia after introduction of the 7-valent pneumococcal conjugate vaccine

OBJECTIVE

To examine rates of paediatric hospitalization for empyema and pneumonia in Australia before and after the introduction of the seven-valent pneumococcal conjugate vaccine (PCV7).

METHODS

Rates of paediatric hospitalization for empyema and pneumonia (bacterial, viral and all types) were calculated following the codes of the International Classification of Diseases, tenth revision (ICD-10) as a principal diagnosis. The expected number of hospitalizations after the PCV7 was introduced was estimated on the basis of the observed number of hospitalizations before the introduction of the PCV7. Incidence rate differences (IRDs) and incidence rate ratios (IRRs) were calculated. Hospitalization incidence in each study period was expressed as the number of hospitalizations per million (10(6)) person-years. The population of children aged 0-19 years in Australia from 1998 to 2004 and from 2005 to 2010, as reported by the Australian Bureau of Statistics, was used to calculate the number of person-years in each period.

FINDINGS

In the 5 years following the introduction of the PCV7, hospitalizations for pneumonia were fewer than expected (15 304 fewer; 95% confidence interval, CI: 14 646-15 960; IRD: -552 per 10(6) person-years; 95% CI: -576 to -529 per 10(6) person-years; IRR: 0.78; 95% CI: 0.77-0.78). Hospitalizations for empyema, on the other hand, were more than expected (83 more; 95% CI: 37-128; IRD: 3 per 10(6) person-years; 95% CI: 1-5 per 10(6) person-years; IRR: 1.35; 95% CI: 1.14-1.59). Reductions in hospitalizations were observed for all ICD-10 pneumonia codes across all age groups. The increase in empyema hospitalizations was only significant among children aged 1 to 4 years.

CONCLUSION

The introduction of the PCV7 in Australia was associated with a substantial decrease in hospitalizations for childhood pneumonia and a small increase in hospitalizations for empyema.

Epidemiology and outcome of severe pneumococcal pneumonia admitted to intensive care unit: a multicenter study

INTRODUCTION

Community-acquired pneumonia (CAP) account for a high proportion of ICU admissions, with Streptococcus pneumoniae being the main pathogen responsible for these infections. However, little is known on the clinical features and outcomes of ICU patients with pneumococcal pneumonia. The aims of this study were to provide epidemiological data and to determine risk factors of mortality in patients admitted to ICU for severe S. pneumoniae CAP.

METHODS

We performed a retrospective review of two prospectively-acquired multicentre ICU databases (2001-2008). Patients admitted for management of severe pneumococcal CAP were enrolled if they met the 2001 American Thoracic Society criteria for severe pneumonia, had life-threatening organ failure and had a positive microbiological sample for S. pneumoniae. Patients with bronchitis, aspiration pneumonia or with non-pulmonary pneumococcal infections were excluded.

RESULTS

Two hundred and twenty two patients were included, with a median SAPS II score reaching 47 [36-64]. Acute respiratory failure (n = 154) and septic shock (n = 54) were their most frequent causes of ICU admission. Septic shock occurred in 170 patients (77%) and mechanical ventilation was required in 186 patients (84%); renal replacement therapy was initiated in 70 patients (32%). Bacteraemia was diagnosed in 101 patients. The prevalence of S. pneumoniae strains with decreased susceptibility to penicillin was 39.7%. Although antibiotherapy was adequate in 92.3% of cases, hospital mortality reached 28.8%. In multivariate analysis, independent risk factors for mortality were age (OR 1.05 (95% CI: 1.02-1.08)), male sex (OR 2.83 (95% CI: 1.16-6.91)) and renal replacement therapy (OR 3.78 (95% CI: 1.71-8.36)). Co-morbidities, macrolide administration, concomitant bacteremia or penicillin susceptibility did not influence outcome.

CONCLUSIONS

In ICU, mortality of pneumococcal CAP remains high despite adequate antimicrobial treatment. Baseline demographic data and renal replacement therapy have a major impact on adverse outcome.

Pharmacodynamics for predicting therapeutic outcome and countering resistance spread: The cefditoren case

The relationship between pharmacokinetics and pharmacodynamics is a key instrument to improve antimicrobial stewardship and should be aimed to identification of the drug exposure measure that is closely associated not only with the ability to kill organisms but also to suppress the emergence of resistant subpopulations. This article reviews published studies for efficacy prediction with cefditoren and those aimed to explore its potential for countering resistance spread, focusing on the three most prevalent community-acquired isolates from respiratory infections: Streptococcus pneumoniae (S. pneumoniae), Haemophilus influenzae (H. influenzae) and Streptococcus pyogenes (S. pyogenes). Studies for efficacy prediction include in vitro pharmacodynamic simulations (using physiological concentrations of human albumin) and mice models (taking advantage of the same protein binding rate in mice and humans) to determine the value of the pharmacodynamic indices predicting efficacy, and Monte Carlo simulations to explore population pharmacodynamic coverage, as weapons for establishing breakpoints. Studies exploring the potential of cefditoren (free concentrations obtained with 400 mg cefditoren bid administration) for countering spread of resistance showed its capability for countering (1) intra-strain spread of resistance linked to ftsI gene mutations in H. influenzae; (2) the spread of H. influenzae resistant strains (with ftsI gene mutations) in multi-strain H. influenzae niches or of S. pneumoniae strains with multiple resistance traits in multi-strain S. pneumoniae niches; and (3) for overcoming indirect pathogenicity linked to β-lactamase production by H. influenzae that protects S. pyogenes in multibacterial niches. This revision evidences the ecological potential for cefditoren (countering resistance spread among human-adapted commensals) and its adequate pharmacodynamic coverage of respiratory pathogens (including those resistant to previous oral compounds) producing community-acquired infections.