Community-acquired pneumonia

Host genetic variants associated with susceptibility and severity of pneumococcal pneumonia in adult patients

BACKGROUND

Pneumococcal community-acquired pneumonia (P-CAP) is a major cause of morbidity and hospitalization. Several host genetics factors influencing risk of pneumococcal disease have been identified, with less information about its association with P-CAP. The aim of the study was to assess the influence of single nucleotide polymorphisms (SNP) within key genes involved in the innate immune response on the susceptibility to P-CAP and to study whether these polymorphic variants were associated with the severity and outcome of the episodes in a cohort of adult Caucasian patients.

METHODS

Seventeen SNPs from 7 genes (IL-R1, IL-4, IL-10, IL-12B, NFKBIA, NFKBIE, NFKBIZ) were analyzed. For susceptibility, a case-control study including a cohort of 57 adult with P-CAP, and 280 ethnically matched controls was performed. Genetic influence on clinical severity and outcome was evaluated in a prospective observational study including all consecutive adult P-CAP patients from November 2015 to May 2017.

RESULTS

The NFKBIA polymorphism rs696 and a haplotype combination were associated with susceptibility to P-CAP (OR = 0.62, p = 0.005 and OR = 0.63, p = 0.008, respectively). The SNP IL4 rs2227284 was associated with severe P-CAP (OR = 2.17, p = 0.04). IL-R1 (rs3917267) and IL-10 (rs3024509) variants were related with respiratory failure (OR = 3.31, p = 0.001 and OR = 0.18, p = 0.003, respectively) as well as several haplotype combinations in NFKBIA, NFKBIZ, IL-R1 and IL-10 (p = 0,02, p = 0,01, p = 0,001, p = 0,03, respectively). CURB-65 values were associated with the IL-10 rs3024509 variant (beta = - 0.4, p = 0.04), and with haplotype combinations of NFKBIZ and IL-10 (p = 0.05, p = 0.04, respectively). Genetic variants in IL-10 (rs3024509) and in IL-12B (rs730691) were associated with PSI values (beta = - 0.54, p = 0.01, and beta = - 0.28, p = 0.04, respectively), as were allelic combinations in IL-R1 (p = 0.02) and IL-10 (p = 0.01). Finally, several polymorphisms in the IL-R1 gene (rs13020778, rs2160227, & rs3917267) were associated with the time elapsed until clinical stability (beta = - 0.83, p = 0.03; beta = - 1, p = 0.02 and beta = 1.07, p = 0.008, respectively).

CONCLUSIONS

A genetic variant in NFKBIA was associated with susceptibility to P-CAP in adult Caucasian patients and genetic variants from key cytokines of the innate immune response (Il-4, IL-10, IL-R1 and IL-12B) and NF-κB inhibitors were associated with different phenotypes of severe P-CAP. If validated, these SNPs may help to identify people at risk of P-CAP or severe P-CAP on which preventive measures could be applied.

A novel biomarker for pleural effusion diagnosis: Interleukin-36γ in pleural fluid

BACKGROUND

Numerous studies have described the critical importance of interleukin (IL) -36γ in host defense against lung infections, but it is unknown whether it plays a role in infectious pleural effusion (IPE). This study aimed to examine the levels of IL-36γ in pleural effusions of different etiologies and evaluate the diagnostic accuracy of IL-36γ in the differential diagnosis of IPE.

METHODS

A total of 112 individuals was enrolled in this research. IL-36γ levels in pleural fluids of all 112 patients were measured by enzyme-linked immunosorbent assay (ELISA). We also characterized these markers' diagnostic values across various groups.

RESULTS

Patients with tuberculous pleural effusion (TPE) and parapneumonic effusion (PPE) had exhibited markedly higher IL-36γ levels in their pleural fluid than the malignant pleural effusion (MPE) and transudative effusion patients. Furthermore, the IL-36γ concentrations in TPE patients were evidently higher than in uncomplicated parapneumonic effusion (UPPE) patients but significantly lower than in complicated parapneumonic effusion (CPPE)/empyema patients. Pleural fluid IL-36γ is a useful marker to differentiate TPE from UPPE, at a cut-off value for 657.5 pg/ml (area under the curve = 0.904, p < 0.0001) with 70.0% sensitivity and 95.7% specificity.

CONCLUSIONS

The elevated IL-36γ in pleural effusion may be used as a novel biomarker for infectious pleural effusion diagnosis, particularly in patients with CPPE/empyema, and is a potentially promising biomarker to differentiate between TPE and UPPE.

Global Perspective of Legionella Infection in Community-Acquired Pneumonia: A Systematic Review and Meta-Analysis of Observational Studies

Legionnaires’ disease (LD) (Legionella) is a common cause of community-acquired pneumonia (CAP) in those requiring hospitalization. Geographical variation in the importance of Legionella species as an aetiologic agent of CAP is poorly understood. We performed a systematic review and meta-analysis of population-based observational studies that reported the proportion of Legionella infection in patients with CAP (1 January 1990 to 31 May 2020). Using five electronic databases, articles were identified, appraised and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The quality of the included studies was assessed using the Newcastle–Ottawa Scale. Univariate and multivariate meta-regression analyses were conducted using study design, WHO region, study quality and healthcare setting as the explanatory variables. We reviewed 2778 studies, of which 219 were included in the meta-analysis. The mean incidence of CAP was 46.7/100,000 population (95% CI: 46.6–46.8). The mean proportion of Legionella as the causative agent for CAP was 4.6% (95% CI: 4.4 to 4.7). Consequently, the mean Legionella incidence rate was 2.8/100,000 population (95% CI: 2.7–2.9). There was significant heterogeneity across all studies I² = 99.27% (p < 0.0001). After outliers were removed, there was a decrease in the heterogeneity (I² = 43.53%). Legionella contribution to CAP has a global distribution. Although the rates appear highest in high income countries in temperate regions, there are insufficient studies from low- and middle-income countries to draw conclusions about the rates in these regions. Nevertheless, this study provides an estimate of the mean incidence of Legionella infection in CAP, which could be used to estimate the regional and global burden of LD to support efforts to reduce the impact of this infection as well as to fill important knowledge gaps.

Interleukin-36 Cytokines in Infectious and Non-Infectious Lung Diseases

The IL-36 family of cytokines were identified in the early 2000’s as a new subfamily of the IL-1 cytokine family, and since then, the role of IL-36 cytokines during various inflammatory processes has been characterized. While most of the research has focused on the role of these cytokines in autoimmune skin diseases such as psoriasis and dermatitis, recent studies have also shown the importance of IL-36 cytokines in the lung inflammatory response during infectious and non-infectious diseases. In this review, we discuss the biology of IL-36 cytokines in terms of how they are produced and activated, as well as their effects on myeloid and lymphoid cells during inflammation. We also discuss the role of these cytokines during lung infectious diseases caused by bacteria and influenza virus, as well as other inflammatory conditions in the lungs such as allergic asthma, lung fibrosis, chronic obstructive pulmonary disease, cystic fibrosis and cancer. Finally, we discuss the current therapeutic advances that target the IL-36 pathway and the possibility to extend these tools to treat lung inflammatory diseases.

Improvement of pneumococcal pneumonia diagnosis using quantitative real-time PCR targeting lytA in adult patients: a prospective cohort study

OBJECTIVES

The aim of the study was to assess the performance of real-time PCR targeting the lytA gene (rtPCR-lytA) in plasma, urine and nasopharyngeal (NP) samples for the diagnosis of pneumococcal community-acquired pneumonia (P-CAP).

METHODS

Prospective observational study including all consecutive adults with CAP from November 2015 to May 2017. P-CAP was defined if pneumococcus was identified using conventional methods (CM) and/or a positive rtPCR-lytA was detected in blood, urine or NP samples (NP cut-off ≥8000 copies/mL). Diagnostic performance of each test was calculated.

RESULTS

A total of 133 individuals with CAP were included. Of these, P-CAP was diagnosed in 62 (46.6%). The proportion of P-CAP diagnosed by rtPCR-lytA methods was significantly higher than that diagnosed by CM (87.1% versus 59.7%, p 0.005). The rtPCR-lytA identified Streptococcus pneumoniae in 25 patients (40.3% of all individuals with P-CAP) whose diagnosis would have been missed by CM. NP-rtPCR-lytA allowed diagnosis of 62.3% of P-CAP. A nasopharyngeal colonization density ≥2351 copies/mL predicted P-CAP diagnosis (area under the curve = 0.82, sensitivity 83.3%, specificity 80.9%). There was a positive correlation between increasing bacterial load in blood and CURB-65 score (Spearman correlation coefficient r = 0.4, p 0.001), pneumonia severity index (r = 0.3, p 0.02) and time to clinical stability (r = 0.33, p 0.01). Median bacterial load in blood was higher in P-CAP patients with bacteraemia (0.65 × 10³ versus 0 × 10³ copies/mL, p 0.002), intensive care unit admission (0.68 × 10³ versus 0 × 10³ copies/mL, p 0.04) or mechanical ventilation (7.45 × 10³ versus 0 × 10³ copies/mL, p 0.04).

CONCLUSIONS

The use of rtPCR-lytA methods significantly increased the diagnosis of P-CAP compared with CM. Nasopharyngeal swabs rtPCR-lytA detection, with an accurate cut-off value, was the most promising among molecular methods for the diagnosis of P-CAP.

Related Factors to Streptococcus pneumoniae Invasive Infection and Clinical Manifestations: The Potential Role of Nasopharyngeal Microbiome

Infections of the lower respiratory tract, such as pneumonia, are one of the leading causes of death worldwide. Streptococcus pneumoniae might colonize the upper respiratory tract and is the main aetiological agent of community-acquired pneumonia (CAP). In the last decades, several factors related to the host, the microorganism and the antibiotic therapy have been investigated to identify risk factors associated with the development of invasive pneumococcal disease (IPD). Nevertheless, these factors themselves do not explain the risk of developing disease or its severity. Recently, some studies have focused on the importance of nasopharyngeal (NP) microbiome and its relation to respiratory health. This review presents existing evidence of the potential role of NP microbiome in the development of IPD.

Short-course versus long-course therapy of the same antibiotic for community-acquired pneumonia in adolescent and adult outpatients

BACKGROUND

Community-acquired pneumonia (CAP) is a lung infection that can be acquired during day-to-day activities in the community (not while receiving care in a hospital). Community-acquired pneumonia poses a significant public health burden in terms of mortality, morbidity, and costs. Shorter antibiotic courses for CAP may limit treatment costs and adverse effects, but the optimal duration of antibiotic treatment is uncertain.

OBJECTIVES

To evaluate the efficacy and safety of short-course versus longer-course treatment with the same antibiotic at the same daily dosage for CAP in non-hospitalised adolescents and adults (outpatients). We planned to investigate non-inferiority of short-course versus longer-term course treatment for efficacy outcomes, and superiority of short-course treatment for safety outcomes.

SEARCH METHODS

We searched CENTRAL, which contains the Cochrane Acute Respiratory Infections Group Specialised Register, MEDLINE, Embase, five other databases, and three trials registers on 28 September 2017 together with conference proceedings, reference checking, and contact with experts and pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing short- and long-courses of the same antibiotic for CAP in adolescent and adult outpatients.

DATA COLLECTION AND ANALYSIS

We planned to use standard Cochrane methods.

MAIN RESULTS

Our searches identified 5260 records. We did not identify any RCTs that compared short- and longer-courses of the same antibiotic for the treatment of adolescents and adult outpatients with CAP.We excluded two RCTs that compared short courses (five compared to seven days) of the same antibiotic at the same daily dose because they evaluated antibiotics (gemifloxacin and telithromycin) not commonly used in practice for the treatment of CAP. In particular, gemifloxacin is no longer approved for the treatment of mild-to-moderate CAP due to its questionable risk-benefit balance, and reported adverse effects. Moreover, the safety profile of telithromycin is also cause for concern.We found one ongoing study that we will assess for inclusion in future updates of the review.

AUTHORS' CONCLUSIONS

We found no eligible RCTs that studied a short-course of antibiotic compared to a longer-course (with the same antibiotic at the same daily dosage) for CAP in adolescent and adult outpatients. The effects of antibiotic therapy duration for CAP in adolescent and adult outpatients remains unclear.

Optimising experimental research in respiratory diseases: an ERS statement

Experimental models are critical for the understanding of lung health and disease and are indispensable for drug development. However, the pathogenetic and clinical relevance of the models is often unclear. Further, the use of animals in biomedical research is controversial from an ethical perspective.The objective of this task force was to issue a statement with research recommendations about lung disease models by facilitating in-depth discussions between respiratory scientists, and to provide an overview of the literature on the available models. Focus was put on their specific benefits and limitations. This will result in more efficient use of resources and greater reduction in the numbers of animals employed, thereby enhancing the ethical standards and translational capacity of experimental research.The task force statement addresses general issues of experimental research (ethics, species, sex, age, ex vivo and in vitro models, gene editing). The statement also includes research recommendations on modelling asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, lung infections, acute lung injury and pulmonary hypertension.The task force stressed the importance of using multiple models to strengthen validity of results, the need to increase the availability of human tissues and the importance of standard operating procedures and data quality.

Comprehensive viral enrichment enables sensitive respiratory virus genomic identification and analysis by next generation sequencing

Next generation sequencing (NGS) technologies have revolutionized the genomics field and are becoming more commonplace for identification of human infectious diseases. However, due to the low abundance of viral nucleic acids (NAs) in relation to host, viral identification using direct NGS technologies often lacks sufficient sensitivity. Here, we describe an approach based on two complementary enrichment strategies that significantly improves the sensitivity of NGS-based virus identification. To start, we developed two sets of DNA probes to enrich virus NAs associated with respiratory diseases. The first set of probes spans the genomes, allowing for identification of known viruses and full genome sequencing, while the second set targets regions conserved among viral families or genera, providing the ability to detect both known and potentially novel members of those virus groups. Efficiency of enrichment was assessed by NGS testing reference virus and clinical samples with known infection. We show significant improvement in viral identification using enriched NGS compared to unenriched NGS. Without enrichment, we observed an average of 0.3% targeted viral reads per sample. However, after enrichment, 50%–99% of the reads per sample were the targeted viral reads for both the reference isolates and clinical specimens using both probe sets. Importantly, dramatic improvements on genome coverage were also observed following virus-specific probe enrichment. The methods described here provide improved sensitivity for virus identification by NGS, allowing for a more comprehensive analysis of disease etiology.

A survey of clinicians regarding respiratory physiotherapy intervention for intubated and mechanically ventilated patients with community-acquired pneumonia. What is current practice in Australian ICUs?

RATIONALE, AIMS, AND OBJECTIVES

Community-acquired pneumonia (CAP) is a common cause for intensive care unit (ICU) admission resulting in high morbidity and mortality. There is a paucity of evidence regarding respiratory physiotherapy for intubated and mechanically ventilated patients with CAP, and anecdotally clinical practice is variable in this cohort. The aims of this study were to identify the degree of variability in physiotherapy practice for intubated adult patients with CAP and to explore ICU physiotherapist perceptions of current practice for this cohort and factors that influence physiotherapy treatment mode, duration, and frequency.

METHOD

A survey was developed based on common aspects of assessment, clinical rationale, and intervention for intubated and mechanically ventilated patients. Senior ICU physiotherapists across 88 Australian public and private hospitals were recruited.

RESULTS

The response rate was 72%. Respondents (n = 75) stated their main rationale for providing a respiratory intervention were improved airway clearance (98%, n = 60/61), alveolar recruitment (74%, n = 45/61), and gas exchange (33%, n = 20/61). Respondents estimated that average intervention lasted between 16 and 30 minutes (70% of respondents, n = 41/59) and would be delivered once (44%) or twice (44%) daily. Results indicated large variability in reported practice; however, trends existed regarding positioning in alternate side-lying (81%, n = 52/64) or affected lung uppermost (83%, n = 53/64) and use of hyperinflation techniques (81%, 52/64). Decisions regarding duration were reported to be based on sputum volume (95%), viscosity (93%) and purulence (88%), cough effectiveness (95%), chest X-ray (87%), and auscultation (84%). Sixty percent reported that workload and staffing affected intervention duration and frequency. Intervention time was more likely increased when there was greater staffing (P = .03).

CONCLUSION

Respiratory physiotherapy treatment varies for intubated patients with CAP. Further research is required to determine what is considered best practice for this patient population.

Efficacy of a respiratory physiotherapy intervention for intubated and mechanically ventilated adults with community acquired pneumonia: a systematic review protocol

REVIEW OBJECTIVES

The objective of the review is to map evidence on the efficacy of a respiratory physiotherapy intervention for intubated and mechanically ventilated adults with community acquired pneumonia (CAP). Specifically, the review seeks to investigate if respiratory physiotherapy interventions can achieve the following for intubated and mechanically ventilated adults with CAP.

Antibiotic Prescribing for Adults Hospitalized in the Etiology of Pneumonia in the Community Study

BACKGROUND

Community-acquired pneumonia (CAP) 2007 guidelines from the Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) recommend a respiratory fluoroquinolone or beta-lactam plus macrolide as first-line antibiotics for adults hospitalized with CAP. Few studies have assessed guideline-concordant antibiotic use for patients hospitalized with CAP after the 2007 IDSA/ATS guidelines. We examine antibiotics prescribed and associated factors in adults hospitalized with CAP.

METHODS

From January 2010 to June 2012, adults hospitalized with clinical and radiographic CAP were enrolled in a prospective Etiology of Pneumonia in the Community study across 5 US hospitals. Patients were interviewed using a standardized questionnaire, and medical charts were reviewed. Antibiotics prescribed were classified according to defined nonrecommended CAP antibiotics. We assessed factors associated with nonrecommended CAP antibiotics using logistic regression.

RESULTS

Among enrollees, 1843 of 1874 (98%) ward and 440 of 446 (99%) ICU patients received ≥1 antibiotic ≤24 hours after admission. Ward patients were prescribed a respiratory fluoroquinolone alone (n = 613; 33%), or beta-lactam plus macrolide (n = 365; 19%), beta-lactam alone (n = 240; 13%), among other antibiotics, including vancomycin (n = 235; 13%) or piperacillin/tazobactam (n = 157; 8%) ≤24 hours after admission. Ward patients with known risk for healthcare-associated pneumonia (HCAP), recent outpatient antibiotic use, and in-hospital antibiotic use <6 hours after admission were significantly more likely to receive nonrecommended CAP antibiotics.

CONCLUSIONS

Although more than half of ward patients received antibiotics concordant with IDSA/ATS guidelines, a number received nonrecommended CAP antibiotics, including vancomycin and piperacillin/tazobactam; risk factors for HCAP, recent outpatient antibiotic, and rapid inpatient antibiotic use contributed to this. This hypothesis-generating descriptive epidemiology analysis could help inform antibiotic stewardship efforts, reinforces the need to harmonize guidelines for CAP and HCAP, and highlights the need for improved diagnostics to better equip clinicians.

Increase in fitness of Streptococcus pneumoniae is associated with the severity of necrotizing pneumonia

BACKGROUND

The incidence of necrotizing pneumococcal pneumonia has increased during the past 2 decades. We hypothesized that increased pneumococcal load or augmented inflammatory cytokine production might lead to destructive pneumococcal lung disease.

METHODS

This study enrolled prospectively 0- to 18-year-old children with a diagnosis of community-acquired pneumonia with pleural effusion admitted to 6 medical centers from March 2010 to April 2012. Children were diagnosed with pneumococcal empyema if the pleural fluid tested positive for quantitative pneumococcal (lytA) detection by real-time polymerase chain reaction. Pneumococcal empyema cases were further divided into 4 groups according to necrosis severity: (0) nonnecrosis, (1) mild necrosis, (2) cavitation and (3) bronchopleural fistula. Nasopharyngeal and pleural pneumococcal load, as well as levels of proinflammatory cytokines (TNF-α, IL-1β, IL-6, IL-8), Th1-(IL-2, IFN-γ), Th2-(IL-4, IL-10) and Th17-cytokines (IL-17), in the pleural fluid was measured.

RESULTS

Serotypes 19A and 3 accounted for 69.4% and 12.5%, respectively, of 72 cases of pneumococcal empyema. Pleural pneumococcal load was significantly higher in serotypes 19A and 3 infection than in the other strains causing infection (P = 0.006). There was a correlation between nasopharyngeal and pleural pneumococcal load (ρ = 0.35; P = 0.05). In multivariate ordinal logistic regression analysis, pleural pneumococcal load (adjusted odds ratio: 1.79; 95% confidence interval: 1.03-3.06) and IL-8 (adjusted odds ratio: 2.64; 95% confidence interval: 1.21-5.75) were independent factors associated with the severity of lung necrosis.

CONCLUSIONS

Evolution of Streptococcus pneumoniae toward increased fitness in their interaction with host and exaggerated IL-8 expression may be responsible for the increase of necrotizing pneumococcal pneumonia.

Impact of the glpQ2 gene on virulence in a Streptococcus pneumoniae serotype 19A sequence type 320 strain

Glycerophosphodiester phosphodiesterase (GlpQ) metabolizes glycerophosphorylcholine from the lung epithelium to produce free choline, which is transformed into phosphorylcholine and presented on the surfaces of many respiratory pathogens. Two orthologs of glpQ genes are found in Streptococcus pneumoniae: glpQ, with a membrane motif, is widespread in pneumococci, whereas glpQ2, which shares high similarity with glpQ in Haemophilus influenzae and Mycoplasma pneumoniae, is present only in S. pneumoniae serotype 3, 6B, 19A, and 19F strains. Recently, serotype 19A has emerged as an epidemiological etiology associated with invasive pneumococcal diseases. Thus, we investigated the pathophysiological role of glpQ2 in a serotype 19A sequence type 320 (19AST320) strain, which was the prevalent sequence type in 19A associated with severe pneumonia and invasive pneumococcal disease in pediatric patients. Mutations in glpQ2 reduced phosphorylcholine expression and the anchorage of choline-binding proteins to the pneumococcal surface during the exponential phase, where the mutants exhibited reduced autolysis and lower natural transformation abilities than the parent strain. The deletion of glpQ2 also decreased the adherence and cytotoxicity to human lung epithelial cell lines, whereas these functions were indistinguishable from those of the wild type in complementation strains. In a murine respiratory tract infection model, glpQ2 was important for nasopharynx and lung colonization. Furthermore, infection with a glpQ2 mutant decreased the severity of pneumonia compared with the parent strain, and glpQ2 gene complementation restored the inflammation level. Therefore, glpQ2 enhances surface phosphorylcholine expression in S. pneumoniae 19AST320 during the exponential phase, which contributes to the severity of pneumonia by promoting adherence and host cell cytotoxicity.

[Clinical features and outcome of community-acquired methicillin-resistant Staphylococcus aureus pneumonia]

INTRODUCTION

The aim of this study is to describe the epidemiological and clinical features, treatment and prognosis of community-acquired pneumonia (CAP) caused by methicillin-resistant Staphylococcus aureus (MRSA) in two different geographic regions where community-acquired MRSA (CA-MRSA) infections have different frequencies.

METHODS

Observational study of patients admitted to two hospitals (one in Argentina, the other in Spain) between March 2008 and June 2012.

RESULTS

We documented 16 cases of CAP caused by MRSA. MRSA accounted for 15 of 547 (2.7%) cases of CAP in Hospital Rodolfo Rossi and 1 of 1258 (0,08%) cases at the Hospital Universitari de Bellvitge (P ≤ .001). Most patients were young and previously healthy. Multilobar infiltrates, cavitation and skin and soft tissue involvement were frequent. All patients had positive blood cultures. Five patients required admission to the intensive care unit. Early mortality (≤ 48 hours) was 19%, and overall mortality (≤ 30 days) was 25%.

CONCLUSION

CAP caused by MRSA causes high morbidity and mortality rates. It should be suspected in areas with a high prevalence of CA-MRSA infections, and especially in young and healthy patients who present with multilobar pneumonia with cavitation. Mortality is mainly related to septic shock and respiratory failure and occurs early in most cases.

Usefulness of gram-stained sputum obtained just after administration of antimicrobial agents as the earliest therapeutic indicator for evaluating the effectiveness of empiric therapy in community-acquired pneumonia caused by pneumococcus or Moraxella catarrhalis

We present here three cases in which morphological changes and/or a decreased number of Streptococcus pneumoniae or Moraxella catarrhalis could be observed in gram-stained sputum obtained just after the first administration of an antimicrobial agent. Case 1 was a 53-year-old man with pneumonia caused by gram-positive diplococcus, identified as S. pneumoniae, who was administered 2 g of ampicillin over a period of 1 h. Gram-stained sputum showed smaller or gram-negative pneumococci at the completion of administration of the agent, a decreased number of cocci at 1 h after administration, and almost no cocci at 12 h after the completion of administration. Case 2 was a 72-year-old woman with pneumonia caused by diplococcus, identified as S. pneumoniae, who was administered 2 g of ampicillin over a period of 1 h. Gram-stained sputum showed weakly stained, small cocci at the completion of administration of the agent and few cocci at 1 h after the completion of administration. Case 3 was a 58-year-old woman with pneumonia caused by a gram-negative diplococcus, identified as Moraxella catarrhalis, who was administered 1 g of cefotaxime over a period of 30 min. Gram-stained sputum showed few extracellular cocci and some intracellular cocci inside neutrophils 1 h after administration and no cocci 2 h after the completion of administration. These three cases showed that gram-stained sputum obtained just after and/or 1 h after administration of the first antimicrobial agent were suitable as the quickest therapeutic indicator of the effectiveness of empiric therapy, with the effectiveness of the agent being shown much earlier than with markers such as the white blood cell count and C-reactive protein level.

Activity of ceftaroline against serotyped Streptococcus pneumoniae isolates from Europe and South Africa associated with community-acquired bacterial pneumonia (2007-08)

OBJECTIVES

To determine the activity of ceftaroline (the active metabolite of the prodrug ceftaroline fosamil), a new cephalosporin recently approved in the USA for the treatment of community-acquired bacterial pneumonia, against serotyped Streptococcus pneumoniae causing community-acquired bacterial pneumonia from Europe and South Africa.

METHODS

During 2007-08, 74 centres submitted 857 isolates of S. pneumoniae from patients with community-acquired bacterial pneumonia. These were re-identified and serotyped. MICs of ceftaroline and 12 comparators were determined by CLSI broth microdilution at a central laboratory.

RESULTS

Ceftaroline was very active against all 857 S. pneumoniae isolates (MIC(90) 0.12 mg/L). The MIC(50) for South African isolates was 0.06 mg/L compared with 0.004 or 0.008 mg/L for isolates from elsewhere. Antibiotic resistance was also higher in South Africa than other countries. Serotypes 3, 1, 7 and 11 were more susceptible to ceftaroline (MIC(90) = 0.008 mg/L) and the reference antibiotics than the population as a whole. Ceftaroline showed a biphasic MIC distribution (associated with cefuroxime susceptibility), the extent of which differed between isolate populations. Nevertheless, the highest ceftaroline MIC observed was only 0.5 mg/L (two isolates: one from the UK and one from South Africa).

CONCLUSIONS

These data from a large collection of S. pneumoniae isolates during 2007-08 from Europe and South Africa with varying serotype and antibiotic susceptibility, confirm the excellent in vitro activity of ceftaroline against S. pneumoniae causing community-acquired bacterial pneumonia in both adults and children.

Aetiology of community-acquired pneumonia among adults in an H1N1 pandemic year: the role of respiratory viruses

This study aimed to determine the aetiology of community-acquired pneumonia (CAP) by adding polymerase chain reaction (PCR) to conventional methods and to describe the clinical and laboratory features between patients with bacterial pneumonia (BP) and viral pneumonia (VP). Adults with CAP admitted from November 2009 to October 2010 were included. Demographics, comorbidities, severity and clinical features were recorded. Conventional microbiological methods included blood and sputum cultures, acute and convalescent serologic samples, and antigen urinary detection. New methods included multiplex PCR for Mycoplasma pneumoniae, Legionella pneumophila, Chlamydophila pneumoniae, Bordetella pertussis and 15 respiratory viruses. A total of 169 patients were included. Using conventional methods, we identified a pathogen in 51 % of cases. With PCR, up to 70 % of cases had an aetiological diagnosis. Forty-five patients had BP (34 %), 22 had VP (17 %) and 25 (19 %) had co-infection (BP and VP). Pneumococci and respiratory syncytial virus (RSV) were the most frequently identified pathogens. Procalcitonin (PCT) and C-reactive protein (CRP) median values were significantly higher in BP than in VP patients. Shaking chills, higher CURB score and shock were significantly more frequent in BP. A viral infection was identified in more than one-third of patients with CAP. Clinical and laboratory features could help to differentiate between VP and BP and to guide empirical therapy.

Timing of antibiotic administration and outcomes of hospitalized patients with community-acquired and healthcare-associated pneumonia

The effects of antibiotic timing on outcomes of patients with community-acquired pneumonia (CAP) are controversial. Moreover, no information is available regarding this issue in healthcare-associated pneumonia (HCAP). We aimed to determine the impact of antibiotic timing on 30-day mortality of patients with CAP and HCAP. Non-immunocompromised adults admitted to hospital through the emergency department (ED) with community-onset pneumonia were prospectively observed from 2001 to 2009. Patients who received prior antibiotics were excluded. Of 1593 patients with pneumonia who were analyzed, 1274 had CAP and 319 HCAP. The mean time from patient arrival at the ED until antibiotic administration was 5.8 h (standard deviation (SD) 3.5) in CAP and 6.1 h (SD 3.8) in HCAP (p 0.30). Mortality was higher in patients with HCAP (5.5% vs. 13.5%; p <0.001). After adjusting for confounding factors in a logistic regression analysis, the antibiotic administration ≤4 h was not associated with decreased 30-day mortality in patients with CAP (odds ratio (OR) 1.12, 95% confidence interval (CI) 0.57-2.21) and in patients with HCAP (OR 0.59, 95% CI 0.19-1.83). Similarly, antibiotic administration ≤8 h was not associated with decreased 30-day mortality in CAP (OR 1.58, 95% CI 0.64-3.88) and HCAP patients (OR 0.59, 95% CI 0.19-1.83). In conclusion, antibiotic administration within 4 or 8 h of arrival at the ED did not improve 30-day survival in hospitalized adults for CAP or HCAP.

Results of a cohort model analysis of the cost-effectiveness of routine immunization with 13-valent pneumococcal conjugate vaccine of those aged > or =65 years in the Netherlands

BACKGROUND

Community-acquired pneumonia and invasive pneumococcal disease are common among older people (ie, those aged > or =65 years). A new 13-valent pneumococcal conjugate vaccine (PCV-13) is under study in the Netherlands.

OBJECTIVE

The aim of this work was to model the cost-effectiveness of PCV-13 vaccination among those aged > or =65 years in the Netherlands, both in the total population and in those at increased risk for pneumonia, for various levels of efficacy (30%-90%) assumed.

METHODS

Our previously published cost-effectiveness model was updated to include age-specific epidemiologic data and health-care utilization and costs for a hypothetical cohort of adults aged > or =65 years in the Netherlands. This cohort was followed twice-once as unvaccinated and once as vaccinated-over a time period of 5 years, with differences between both analyses reported. Outcome measures included costs, life-years gained (LYGs), quality-adjusted life-years, and incremental cost-effectiveness ratios (ICERs). All analyses were performed from a societal perspective.

RESULTS

In the model, the ICER for vaccination remained below euro80,000/LYG, except when the vaccine was assumed to protect only against bacteremic pneumonia, with a relatively low effectiveness (40%) in combination with a high vaccine price (euro65), and indirect effects of serotype replacement would largely offset the direct effect of vaccination. For various assumptions, introduction of widespread PCV-13 vaccination (assuming a 60% efficacy against invasive and noninvasive disease because of vaccine serotypes, and a cost of euro50 per vaccinated person) was associated with the ICERs varying from cost-saving to euro50,676/LYG.

CONCLUSIONS

In this model analysis of a hypothetical cohort in the Netherlands, vaccination with PCV-13 might be considered cost-effective, both for the total population and for the high-risk population aged > or =65 years, from a societal perspective, over a 5-year time horizon. The main limitation of this study was uncertainty regarding how great a proportion of pneumonia could be attributed to pneumococcal disease.

Aetiology of community-acquired pneumonia in hospitalized adult patients in New Caledonia

OBJECTIVE

To describe the aetiology of community-acquired pneumonia (CAP) in hospitalized adult patients in New Caledonia, a French archipelago in the South Pacific.

METHODS

Confirmed CAP patients (n=137) were enrolled prospectively. Pathogens were detected by culture, molecular methods, serology on paired sera, immunofluorescence on nasopharyngeal swabs and antigen detection in urine.

RESULTS

The aetiology of CAP was determined in 82 of 137 cases (59.8%), of which 31 exhibited two or more pathogens (37.8%). Hundred and seventeen pathogens were detected: Streptococcus pneumoniae was the most common one (41.0%), followed by influenza virus A (22.1%) and Haemophilus influenzae (10.2%). The frequency of atypical bacteria was low (6.0%). The most frequent and significant coinfection was S. pneumoniae with influenza A virus (P=0.004). Influenza virus was detected from nasopharyngeal swabs in four patients (15.4% of patients tested for influenza) and by PCR from pulmonary specimens in 15 patients (57.7%). CONCLUSIONS : Pneumoniae is the leading cause of CAP in New Caledonian adults. Viral-bacterial co-infections involving S. pneumoniae and influenza virus are very common during the winter. Such adult patients hospitalized with CAP are a clear sentinel group for surveillance of influenza. Vaccination against influenza and S. pneumoniae should be strengthened when risk factors are identified.

Usefulness of triggering receptor expressed on myeloid cells-1 in differentiating between typical and atypical community-acquired pneumonia

OBJECTIVES

The purpose of this study is to investigate the clinical use of inflammatory marker triggering receptor expressed on myeloid cells (TREM)-1 at admission for differentiating between typical and atypical bacterial community-acquired pneumonia (CAP).

METHODS

A prospective, noninterventional study of patients with CAP hospitalized through the emergency department was performed. Surface expression of TREM-1 was analyzed using flow cytometry on peripheral blood cells, and soluble TREM-1 (sTREM-1) concentration was determined in plasma.

RESULTS

Eighty-eight patients with clinical suspicion of CAP were eligible. The causative pathogen was identified in 39 patients (44.3%). After excluding 4 mixed pneumonia cases, 21 typical and 14 atypical bacterial infections were enrolled. Patients with typical bacterial CAP demonstrated increased TREM-1 surface expression on monocytes and neutrophils. Median plasma sTREM-1 levels at admission were 65.2 pg/mL (range, 17.6-138.1 pg/mL) in patients with typical CAP and 25.9 pg/mL (range, 11.5-54.8 pg/mL) in patients with atypical CAP (P < .001). Soluble TREM-1 had good discriminative value to differentiate typical from atypical pathogens with an area under the receiver operating characteristic curve of 0.87 (95% confidence interval, 0.75-0.98). At a cutoff level of 44.2 pg/mL, sTREM-1 yielded a sensitivity of 81%, a specificity of 79%, a positive likelihood ratio of 3.79, and a negative likelihood ratio of 0.24.

CONCLUSIONS

In newly admitted patients with CAP, determination of the TREM-1 levels may provide useful additional diagnostic information on the bacterial etiology.

Reduced immunoglobulin M is associated with sinus mucosal thickening, osteitis and sinus surgery in patients with common variable immunodeficiency

BACKGROUND

Although common variable immunodeficiency (CVID) is associated with sinopulmonary disease, there are no previous systematic evaluations comparing computed tomographic (CT) sinus imaging with immunoglobulin measurements in patients with this condition.

METHODS

We performed a retrospective review by a blinded observer using the Lund-Mackay numerical scoring scale as well as a visual scale for remodeling changes in the paranasal sinus bone on CT scans in CVID patients.

RESULTS

The sinus CT scans of 19 subjects (9 males, 10 females; median age at diagnosis 34 years) are described. There was an inverse relationship between serum IgM and sinus mucosal thickening as described by the Lund-Mackay scale (R = -0.6398; p = 0.0032). Osteitis of the paranasal sinus bone was almost exclusively found in patients with a reduced serum IgM level of less than 25 mg/dl (p = 0.0074).

CONCLUSION

This is the first study to show that sinus mucosal thickening on CT in patients with CVID is inversely related to serum IgM levels.

Aetiology of, and risk factors for, recurrent community-acquired pneumonia

Recurrent community-acquired pneumonia (CAP) requiring hospitalization is a matter of particular concern. However, current information on its prevalence, aetiology and risk factors is lacking. To address these issues, we performed an observational analysis of a prospective cohort of hospitalized adults with CAP. Recurrence was defined as two or more episodes of CAP 1 month apart within 3 years. Patients with severe immunosuppression or local predisposing factors were excluded. Of the 1556 patients, 146 (9.4%) had recurrent CAP. The most frequent causative organism was Streptococcus pneumoniae, both in patients with recurrent CAP and in those without recurrence. Haemophilus influenzae, other Gram-negative bacilli and aspiration pneumonia were more frequent among patients with recurrent CAP, whereas Legionella pneumophila was rarely identified in this group. Independent factors associated with recurrent CAP were greater age, lack of pneumococcal vaccination, chronic obstructive pulmonary disease (COPD) and corticosteroid therapy. In a sub-analysis of 389 episodes of pneumococcal pneumonia, the only independent risk factor for recurrence was lack of pneumococcal vaccination. Recurrence of CAP is not a rare clinical problem and it occurs mainly in the elderly, patients with COPD, and those receiving corticosteroids. Our study provides support for recommending pneumococcal vaccination for adults at risk of pneumonia, including those with a first episode of CAP.

Therapy for pneumococcal bacteremia: monotherapy or combination therapy?

PURPOSE OF REVIEW

The issue of whether the outcome of bacteremic pneumococcal infections is improved with the use of combination antibiotic therapy versus monotherapy is still not resolved. This review highlights recent studies that have addressed this issue.

RECENT FINDINGS

Some studies have indicated benefit of combination antibiotic therapy in severely ill patients with community-acquired pneumonia of all-cause. Conversely, in less severely ill hospitalized patients, fluoroquinolone monotherapy was as effective as fluoroquinolone combination regimens and a propensity analysis failed to show benefit of beta-lactam/macrolide combination over beta-lactam monotherapy. Studies across the world have shown a more favorable outcome in patients with community-acquired pneumonia treated with guideline-compliant therapy, mostly beta-lactam/macrolide combination regimens. The only recent study of patients with bacteremic pneumococcal pneumonia failed, however, to show benefit of combination therapy. A large number of investigations have yielded observations that address possible mechanisms by which combination therapy may have benefit, investigating issues such as cover for atypical pathogens, attenuation of pneumococcal virulence factors, and anti-inflammatory activity of the macrolide group of antibiotics.

SUMMARY

Despite a number of recent studies, the definitive decision regarding the need for combination antibiotic therapy for the effective management of bacteremic pneumococcal infections has not yet been formally resolved.