Severe community-acquired pneumonia

Exendin-4 blockade of T1R2/T1R3 activation improves Pseudomonas aeruginosa-related pneumonia in an animal model of chemically induced diabetes

OBJECTIVE

Poorly controlled diabetes frequently exacerbates lung infection, thereby complicating treatment strategies. Recent studies have shown that exendin-4 exhibits not only hypoglycemic but also anti-inflammatory properties. This study aimed to explore the role of exendin-4 in lung infection with diabetes, as well as its association with NOD1/NF-κB and the T1R2/T1R3 sweet taste receptor.

METHODS

16HBE human bronchial epithelial cells cultured with 20 mM glucose were stimulated with lipopolysaccharide (LPS) isolated from Pseudomonas aeruginosa (PA). Furthermore, Sprague‒Dawley rats were fed a high-fat diet, followed by intraperitoneal injection of streptozotocin and intratracheal instillation of PA. The levels of TNF-α, IL-1β and IL-6 were evaluated using ELISAs and RT‒qPCR. The expression of T1R2, T1R3, NOD1 and NF-κB p65 was assayed using western blotting and immunofluorescence staining. Pathological changes in the lungs of the rats were observed using hematoxylin and eosin (H&E) staining.

RESULTS

At the same dose of LPS, the 20 mM glucose group produced more proinflammatory cytokines (TNF-α, IL-1β and IL-6) and had higher levels of T1R2, T1R3, NOD1 and NF-κB p65 than the normal control group (with 5.6 mM glucose). However, preintervention with exendin-4 significantly reduced the levels of the aforementioned proinflammatory cytokines and signaling molecules. Similarly, diabetic rats infected with PA exhibited increased levels of proinflammatory cytokines in their lungs and increased expression of T1R2, T1R3, NOD1 and NF-κB p65, and these effects were reversed by exendin-4.

CONCLUSIONS

Diabetic hyperglycemia can exacerbate inflammation during lung infection, promote the increase in NOD1/NF-κB, and promote T1R2/T1R3. Exendin-4 can ameliorate PA-related pneumonia with diabetes and overexpression of NOD1/NF-κB. Additionally, exendin-4 suppresses T1R2/T1R3, potentially through its hypoglycemic effect or through a direct mechanism. The correlation between heightened expression of T1R2/T1R3 and an intensified inflammatory response in lung infection with diabetes requires further investigation.

Recovery Time From Severe Community Acquired Pneumonia and Risk Factors Among Pediatrics, Ethiopia: A Retrospective Follow-Up Study

Introduction. Severe community acquired pneumonia (CAP) is a life-threatening condition, with high rates of morbidity and mortality. This study aimed to determine the recovery time from severe CAP and risk factors among pediatric patients. Methods. A retrospective follow-up study was conducted among 412 pediatric medical charts with severe CAP enrolled at Asella Referral and Teaching Hospital between January 01, 2021 and December 31, 2022. EpiData version 4.6.0.6 and STATA version 14.2 were used for data entry and statistical analysis, respectively. Bivariable and multivariable Cox proportional hazards regression analyzes were performed. Result. The median recovery time from severe CAP among pediatric patients was 5 days (IQR = 3-8 days). IDR of recovery from severe CAP was 13.089 per 100 [95%CI: 11.82, 14.49] pediatric days observations. The cumulative incidence of recovery from severe CAP was 89.56% [n = 369, 95%CI: 86.20, 92.18]. Age [AHR = 1.55, 95%CI: 1.12, 2.13, P = .007], vaccination status [AHR = 1.29, 95%CI: 1.03, 1.63, P = .027], presence of danger signs [AHR = 1.61, 95%CI: 1.26, 2.05, P = .000], presence of comorbidity [AHR = 1.67, 95%CI: 1.33, 2.10, P = .000], duration of seeking care [AHR = 1.71, 95%CI: 1.18, 2.47, P = .004], and oxygen therapy [AHR = 1.45, 95%CI:1.12, 1.87, P = .004] were statistically significant risk factors for recovery time from severe CAP. Conclusions. The median recovery time of patients with severe CAP is relatively high. Age, vaccination status, presence of danger signs, presence of comorbidities, duration of seeking care, and oxygen therapy were statistically significant risk factors of recovery time from severe CAP.

The safety and efficacy of stem cells for the treatment of severe community-acquired bacterial pneumonia: A randomized clinical trial

PURPOSE

Evaluate the safety profile of expanded allogeneic adipose-derived mesenchymal stem cell (eASC) for the treatment of severe community-acquired bacterial pneumonia (CABP).

MATERIALS AND METHODS

Randomized, multicenter, double-blind, placebo-controlled, phase 1b/2a trial. Patients with severe CABP were enrolled to receive intravenous infusions of Cx611 or placebo. The primary objective was safety including hypersensitivity reactions, thromboembolic events, and immunological responses to Cx611. The secondary endpoints included the clinical cure rate, ventilation-free days, and overall survival (Day 90).

RESULTS

Eighty-three patients were randomized and received infusions (Cx611: n = 42]; placebo: n = 41]. The mean age was similar (Cx611: 61.1 [11.2] years; placebo: 63.4 [10.4] years). The number of AEs and treatment-emergent AEs were similar (243; 184 and 2; 1) in Cx611 and placebo respectively. Hypersensitivity reactions or thromboembolic events were similar (Cx611: n = 9; placebo: n = 12). Each study arm had similar anti-HLA antibody/DSA levels at Day 90. The clinical cure rate (Cx611: 86.7%; placebo: 93.8%), mean number of ventilator-free days (Cx611: 12.2 [10.29] days; placebo: 15.4 [10.75] days), and overall survival (Cx611: 71.5%; placebo: 77.0%) did not differ between study arms.

CONCLUSION

Cx611 was well tolerated in severe CABP. These data provide insights for future stem cell clinical study designs, endpoints and sample size calculation.

TRIAL REGISTRATION

NCT03158727 (retrospectively registered: May 09, 2017). Full study protocol: https://clinicaltrials.gov/ProvidedDocs/27/NCT03158727/Prot_000.pdf.

Volatile organic compounds in headspace characterize isolated bacterial strains independent of growth medium or antibiotic sensitivity

INTRODUCTION

Early and reliable determination of bacterial strain specificity and antibiotic resistance is critical to improve sepsis treatment. Previous research demonstrated the potential of headspace analysis of volatile organic compounds (VOCs) to differentiate between various microorganisms associated with pulmonary infections in vitro. This study evaluates whether VOC analysis can also discriminate antibiotic sensitive from resistant bacterial strains when cultured on varying growth media.

METHODS

Both antibiotic-sensitive and -resistant strains of Pseudomonas aeruginosa, Staphylococcus aureus and Klebsiella pneumonia were cultured on 4 different growth media, i.e. Brain Heart Infusion, Marine Broth, Müller-Hinton and Trypticase Soy Agar. After overnight incubation at 37°C, the headspace air of the cultures was collected on stainless steel desorption tubes and analyzed by gas chromatography time-of-flight mass spectrometry (GC-tof-MS). Statistical analysis was performed using regularized multivariate analysis of variance and cross validation.

RESULTS

The three bacterial species could be correctly recognized based on the differential presence of 14 VOCs (p<0.001). This discrimination was not influenced by the different growth media. Interestingly, a clear discrimination could be made between the antibiotic-resistant and -sensitive variant of Pseudomonas aeruginosa (p<0.001) based on their species-specific VOC signature.

CONCLUSION

This study demonstrates that isolated microorganisms, including antibiotic-sensitive and -resistant strains of Pseudomonas aeruginosa, could be identified based on their excreted VOCs independent of the applied growth media. These findings suggest that the discriminating volatiles are associated with the microorganisms themselves rather than with their growth medium. This study exemplifies the potential of VOC analysis as diagnostic tool in medical microbiology. However, validation of our results in appropriate in vivo models is critical to improve translation of breath analysis to clinical applications.

Reprogramming of Amino Acid Metabolism Differs between Community-Acquired Pneumonia and Infection-Associated Exacerbation of Chronic Obstructive Pulmonary Disease

Amino acids and their metabolites are key regulators of immune responses, and plasma levels may change profoundly during acute disease states. Using targeted metabolomics, we evaluated concentration changes in plasma amino acids and related metabolites in community-acquired pneumonia (CAP, n = 29; compared against healthy controls, n = 33) from presentation to hospital through convalescence. We further aimed to identify biomarkers for acute CAP vs. the clinically potentially similar infection-triggered COPD exacerbation (n = 13). Amino acid metabolism was globally dysregulated in both CAP and COPD. Levels of most amino acids were markedly depressed in acute CAP, and total amino acid concentrations on admission were an accurate biomarker for the differentiation from COPD (AUC = 0.93), as were reduced asparagine and threonine levels (both AUC = 0.92). Reduced tryptophan and histidine levels constituted the most accurate biomarkers for acute CAP vs. controls (AUC = 0.96, 0.94). Only kynurenine, symmetric dimethyl arginine, and phenylalanine levels were increased in acute CAP, and the kynurenine/tryptophan ratio correlated best with clinical recovery and resolution of inflammation. Several amino acids did not reach normal levels by the 6-week follow-up. Glutamate levels were reduced on admission but rose during convalescence to 1.7-fold above levels measured in healthy control. Our data suggest that dysregulated amino acid metabolism in CAP partially persists through clinical recovery and that amino acid metabolism constitutes a source of promising biomarkers for CAP. In particular, total amino acids, asparagine, and threonine may constitute plasma biomarker candidates for the differentiation between CAP and infection-triggered COPD exacerbation and, perhaps, the detection of pneumonia in COPD.

Estimating the True Burden of Legionnaires' Disease

Over the past decade, the reported incidence of Legionnaires' disease (LD) in the northeastern United States has increased, reaching 1-3 cases per 100,000 population. There is reason to suspect that this is an underestimate of the true burden, since LD cases may be underdiagnosed. In this analysis of pneumonia and influenza (P&I) hospitalizations, we estimated the percentages of cases due to Legionella, influenza, and respiratory syncytial virus (RSV) by age group. We fitted mixed-effects models to estimate attributable percents using weekly time series data on P&I hospitalizations in Connecticut from 2000 to 2014. Model-fitted values were used to calculate estimates of numbers of P&I hospitalizations attributable to Legionella (and influenza and RSV) by age group, season, and year. Our models estimated that 1.9%, 8.8%, and 5.1% of total (all-ages) inpatient P&I hospitalizations could be attributed to Legionella, influenza, and RSV, respectively. Only 10.6% of total predicted LD cases had been clinically diagnosed as LD during the study period. The observed incidence rate of 1.2 cases per 100,000 population was substantially lower than our estimated rate of 11.6 cases per 100,000 population. Our estimates of numbers of P&I hospitalizations attributable to Legionella are comparable to those provided by etiological studies of community-acquired pneumonia and emphasize the potential for underdiagnosis of LD in clinical settings.

Focused upon hybridization: rapid and high sensitivity detection of DNA using isotachophoresis and peptide nucleic acid probes

We present a novel assay for rapid and high sensitivity detection of nucleic acids without amplification. Utilizing the neutral backbone of peptide nucleic acids (PNA), our method is based on the design of low electrophoretic mobility PNA probes, which do not focus under isotachophoresis (ITP) unless bound to their target sequence. Thus, background noise associated with free probes is entirely eliminated, significantly improving the signal-to-noise ratio while maintaining a simple single-step assay requiring no amplification steps. We provide a detailed analytical model and experimentally demonstrate the ability to detect targets as short as 17 nucleotides (nt) and a limit of detection of 100 fM with a dynamic range of 5 decades. We also demonstrate that the assay can be successfully implemented for detection of DNA in human serum without loss of signal. The assay requires 15 min to complete, and it could potentially be used in applications where rapid and highly sensitive amplification-free detection of nucleic acids is desired.

Plasma-derived human C1-esterase inhibitor does not prevent mechanical ventilation-induced pulmonary complement activation in a rat model of Streptococcus pneumoniae pneumonia

Mechanical ventilation has the potential to cause lung injury, and the role of complement activation herein is uncertain. We hypothesized that inhibition of the complement cascade by administration of plasma-derived human C1-esterase inhibitor (C1-INH) prevents ventilation-induced pulmonary complement activation, and as such attenuates lung inflammation and lung injury in a rat model of Streptococcus pneumoniae pneumonia. Forty hours after intratracheal challenge with S. pneumoniae causing pneumonia rats were subjected to ventilation with lower tidal volumes and positive end-expiratory pressure (PEEP) or high tidal volumes without PEEP, after an intravenous bolus of C1-INH (200 U/kg) or placebo (saline). After 4 h of ventilation blood, broncho-alveolar lavage fluid and lung tissue were collected. Non-ventilated rats with S. pneumoniae pneumonia served as controls. While ventilation with lower tidal volumes and PEEP slightly amplified pneumonia-induced complement activation in the lungs, ventilation with higher tidal volumes without PEEP augmented local complement activation more strongly. Systemic pre-treatment with C1-INH, however, failed to alter ventilation-induced complement activation with both ventilation strategies. In accordance, lung inflammation and lung injury were not affected by pre-treatment with C1-INH, neither in rats ventilated with lower tidal volumes and PEEP, nor rats ventilated with high tidal volumes without PEEP. Ventilation augments pulmonary complement activation in a rat model of S. pneumoniae pneumonia. Systemic administration of C1-INH, however, does not attenuate ventilation-induced complement activation, lung inflammation, and lung injury.

The two-way relationship between medical illness and late-life depression

This article reviews some common medical conditions and the interaction between those illnesses and depression in the geriatric population. The authors aim to help clarify the 2-way interaction between depression and these medical conditions, especially in older individuals, and impart some important diagnostic and treatment considerations to the practicing physician. The presence of multiple conditions further complicates treatment, as does associated medication use, substance abuse problems (often underappreciated in the elderly), age-related changes in sleep architecture, and an array of other psychosocial and environmental factors that can contribute to the development of depression.

Lower Respiratory Tract Infections

Lower respiratory tract infections are common and are important in the critical care setting either because they precipitate admission to the critical care unit, e.g. severe viral pneumonia or because they complicate the course of a patient with significant underlying disease or following major surgery, e.g. after multiple trauma. Furthermore, respiratory failure requiring artifical ventialtion is a well recognised reason for critical care support but it can be difficult to determine if this is due to an underlying non-infectious condition such as chronic obstructive pulmonary disease (COPD), infection or a combination of both. The early diagnosis and management of respiratory infection combined with appropriate ventilatory support aids prognosis and the efficient use of critical care facilities given the number of patients affected.

Opportunity for healthy ageing: lessening the burden of adult pneumococcal disease in Central and Eastern Europe, and Israel

The population of the Region (Central Europe, Eastern Europe, and Israel) is ageing, necessitating preventative programmes to maintain a healthy and active lifestyle in older age groups. Invasive pneumococcal disease (including bacteremic pneumonia, bacteremia without a focus, and meningitis) has higher incidence, morbidity and mortality in older adults and is a substantial public health burden in the ageing population. Surveillance in the Region establishes a significant burden in older adults of invasive pneumococcal disease (IPD), which still appears to be under-estimated as compared with other countries, and this warrants an improvement in surveillance systems. The largest proportion of IPD in adults is bacteremic pneumonia. Community-acquired pneumonia (CAP), largely attributable to S. pneumoniae, can be bacteremic or non-bacteremic; the non-bacteremic forms of CAP also represent a significant burden in the Region. The burden of pneumococcal disease can be reduced with programmes of effective vaccination. Recommendations on pneumococcal vaccination in adults vary widely across the Region. The main barrier to implementation of vaccination programmes is low awareness among healthcare professionals on serious heatlh consequences of adult pneumococcal disease and of vaccination options. The Expert Panel calls on healthcare providers in the Region to improve pneumococcal surveillance, optimize and disseminate recommendations for adult vaccination, and support awareness and education programmes about adult pneumococcal disease.

Prediction of severe community-acquired pneumonia: a systematic review and meta-analysis

Introduction

Severity assessment and site-of-care decisions for patients with community-acquired pneumonia (CAP) are pivotal for patients' safety and adequate allocation of resources. Late admission to the intensive care unit (ICU) has been associated with increased mortality in CAP. We aimed to review and meta-analyze systematically the performance of clinical prediction rules to identify CAP patients requiring ICU admission or intensive treatment.

Methods

We systematically searched Medline, Embase, and the Cochrane Controlled Trials registry for clinical trials evaluating the performance of prognostic rules to predict the need for ICU admission, intensive treatment, or the occurrence of early mortality in patients with CAP.

Results

Sufficient data were available to perform a meta-analysis on eight scores: PSI, CURB-65, CRB-65, CURB, ATS 2001, ATS/IDSA 2007, SCAP score, and SMART-COP. The estimated AUC of PSI and CURB-65 scores to predict ICU admission was 0.69. Among scores proposed for prediction of ICU admission, ATS-2001 and ATS/IDSA 2007 scores had better operative characteristics, with a sensitivity of 70% (CI, 61 to 77) and 84% (48 to 97) and a specificity of 90% (CI, 82 to 95) and 78% (46 to 93), but their clinical utility is limited by the use of major criteria.

ATS/IDSA 2007 minor criteria have good specificity (91% CI, 84 to 95) and moderate sensitivity (57% CI, 46 to 68). SMART-COP and SCAP score have good sensitivity (79% CI, 69 to 97, and 94% CI, 88 to 97) and moderate specificity (64% CI, 30 to 66, and 46% CI, 27 to 66). Major differences in populations, prognostic factor measurement, and outcome definition limit comparison. Our analysis also highlights a high degree of heterogeneity among the studies.

Conclusions

New severity scores for predicting the need for ICU or intensive treatment in patients with CAP, such as ATS/IDSA 2007 minor criteria, SCAP score, and SMART-COP, have better discriminative performances compared with PSI and CURB-65. High negative predictive value is the most consistent finding among the different prediction rules. These rules should be considered an aid to clinical judgment to guide ICU admission in CAP patients.

Towards a sensible comprehension of severe community-acquired pneumonia

Four different rules have been suggested and validated for intensive care unit (ICU) admission for community-acquired pneumonia: modified American Thoracic Society (ATS) rule, Infectious Diseases Society of America (IDSA)/ATS rule, España rule, and SMART-COP. Their performance varies, with sensitivity of around 70% and specificity of around 80-90%. Only negative predictive values are consistently high. Critical methodological issues include the appropriate reference for derivation, the populations studied, the variables included, and the time course of pneumonia. Severe community-acquired pneumonia (SCAP) may evolve because of acute respiratory failure or/and severe sepsis/septic shock. Pneumonia-related complications and decompensated comorbidities may be additional or independent reasons for a severe course. All variables included in predictive rules relate to the two principal reasons for SCAP. However, taken as major criteria, they are of little value for clinical assessment. Instead, a limited set of minor criteria reflecting severity seems appropriate. However, predictive rules may not meet principal needs of severity assessment because of failure in sensitivity, ignorance of the potential contribution of complications or decompensated comorbidity to pneumonia severity, and poor sensitivity for the lower extreme in the spectrum of severe pneumonia, i.e., patients at risk of SCAP. We therefore advocate an approach that refers to the evaluation of the need for intensified treatment rather than ICU, based on a set of minor criteria and sensitive to the dynamic nature of pneumonia. Intensified treatment such as monitoring and treatment of acute respiratory failure or/and severe sepsis/septic shock is thought to improve management and possibly outcomes by setting the focus on both patients with severity criteria at admission and those at risk for SCAP.

Community-acquired Legionella pneumonia: new insights from the German competence network for community acquired pneumonia

BACKGROUND

The Competence Network for Community Acquired Pneumonia (CAPNETZ) offers a unique opportunity to study the epidemiology of legionellosis throughout Germany, applying sophisticated diagnostic tools.

METHODS

The incidence, clinical characteristics, and outcome of Legionella pneumonia in 2503 adult patients with community-acquired pneumonia, participating in the German Multicenter Study of the CAPNETZ, were studied.

RESULTS

Legionella pneumonia was diagnosed in 94 patients (3.8%), thus identifying Legionella species as one of the most common pathogens to cause community-acquired pneumonia. It was equally common among ambulatory and hospitalized patients (3.7% and 3.8%, respectively). The predominant species causing community-acquired pneumonia was Legionella pneumophila; however, 10% of cases were caused by other species not detectable by the urinary antigen test. Patients whose disease was diagnosed by urinary antigen testing experienced a more severe clinical course. Compared with hospitalized patients, ambulatory patients with Legionella pneumonia showed an equal sex distribution, were younger, had fewer comorbidities, fewer cases of discordant initial antimicrobial treatment, and a milder clinical course without fatalities. Thirty percent of patients with Legionella pneumonia received discordant initial antimicrobial treatment without increased mortality.

CONCLUSIONS

Legionella is a leading cause of community-acquired pneumonia in Germany. It needs to be considered equally in hospitalized and ambulatory patients. A positive result of a urine antigen test is associated with a more severe clinical course and leads to a potentially relevant underrecognition of species other than L. pneumophila. Legionella pneumonia in outpatients differs significantly from that in hospitalized patients in terms of clinical presentation and outcome. There was an unacceptably high rate of discordant initial antimicrobial treatment.

Clinical and microbiological characteristics of community-acquired pneumonia among human immunodeficiency virus-infected patients in northern Thailand

Human immunodeficiency virus (HIV) infections are prevalent in Thailand. However, the clinical and microbiological characteristics of community-acquired pneumonia (CAP) in such patients are not completely clear at present. In the present study, we analyzed the characteristics of CAP in 191 HIV-infected patients (192 episodes, 130 males and 61 females, mean age 32.9 years, range: 20-62) who had been admitted to Nakornping Hospital in northern Thailand between December 1996 and January 2002. The mean peripheral blood CD4 lymphocyte count was 68.5/mm3 (range: 0-791). The most common organisms detected in the blood of the subjects were as follows: Penicillium marneffei, 13, Salmonella spp., 5, Cryptococcus neoformans, 4, Staphylococcus aureus, 3, and Rhodococcus equi, 3, and the most common organisms detected in sputum included Haemophilus influenzae, 38, P. marneffei, 10, Streptococcus pneumoniae, 10, R. equi, 9, and S. aureus, 9. Life-threatening meningitis in 5 (cryptococcal in 3 and tuberculous in 2), pneumothorax in 2, and tuberculous lymphadenitis in 1 were also noted, resulting in 21 fatalities (10.9%). The mean peripheral blood CD4 lymphocyte count for cases in which the subject died was 74.8/mm3 (range: 0-340). Logistic regression analysis demonstrated that high age (odds ratio of over 40 years: 15.62) and R. equi infection (odds ratio: 8.14) are related to death of HIV-infected patients with CAP. The above findings indicate that various types of organisms, including mixed organisms, cause CAP in HIV-infected patients in northern Thailand, and high age and R. equi infection seem to be risk factors for death.

A quantitative microbial risk assessment model for Legionnaires' disease: animal model selection and dose-response modeling

Legionnaires' disease (LD), first reported in 1976, is an atypical pneumonia caused by bacteria of the genus Legionella, and most frequently by L. pneumophila (Lp). Subsequent research on exposure to the organism employed various animal models, and with quantitative microbial risk assessment (QMRA) techniques, the animal model data may provide insights on human dose-response for LD. This article focuses on the rationale for selection of the guinea pig model, comparison of the dose-response model results, comparison of projected low-dose responses for guinea pigs, and risk estimates for humans. Based on both in vivo and in vitro comparisons, the guinea pig (Cavia porcellus) dose-response data were selected for modeling human risk. We completed dose-response modeling for the beta-Poisson (approximate and exact), exponential, probit, logistic, and Weibull models for Lp inhalation, mortality, and infection (end point elevated body temperature) in guinea pigs. For mechanistic reasons, including low-dose exposure probability, further work on human risk estimates for LD employed the exponential and beta-Poisson models. With an exposure of 10 colony-forming units (CFU) (retained dose), the QMRA model predicted a mild infection risk of 0.4 (as evaluated by seroprevalence) and a clinical severity LD case (e.g., hospitalization and supportive care) risk of 0.0009. The calculated rates based on estimated human exposures for outbreaks used for the QMRA model validation are within an order of magnitude of the reported LD rates. These validation results suggest the LD QMRA animal model selection, dose-response modeling, and extension to human risk projections were appropriate.

Polmoniti

Non è semplice ordinare una materia così articolata come la patologia infettiva respiratoria. La gestione delle polmoniti si presenta complessa per le problematiche ad esse connesse (aspetti epidemiologici, microbiologici, farmacoeconomici, ecc.) per cui è necessario confrontare costantemente le conoscenze di quanti hanno dimestichezza in questo settore per proporre e condividere linee strategiche che tengano in considerazione da un lato i suggerimenti contenuti nelle linee guida più accreditate e dall’altro le esperienze prodotte dalla pratica quotidiana al fine di migliorare potenzialità e metodi di cura e razionalizzare i percorsi diagnostico-terapeutici più idonei a fronteggiarle. L’incremento costante delle infezioni respiratorie sostenute dai patogeni emergenti e interessate dal fenomeno delle resistenze batteriche è oggi un elemento preoccupante che rischia, tra l’altro, di vanificare, in carenza di un adeguamento costante, tutti gli schemi, le linee guida e i protocolli diagnostico-terapeutici elaborati in questi ultimi anni per un razionale trattamento delle patologie pneumoinfettivologiche. Il trattamento delle polmoniti acquisite in comunità (CAP) rappresenta uno degli argomenti più dibattuti in pneumologia negli ultimi anni, sottoposto a continue revisioni, aggiornamenti, precisazioni dottrinarie.

Impact of rapid detection of viral and atypical bacterial pathogens by real-time polymerase chain reaction for patients with lower respiratory tract infection

Background. Rapid diagnostic tests with a high sensitivity for lower respiratory tract infection (LRTI) could lead to improved patient care and reduce unnecessary antibiotic use and associated costs. Diagnostic yields, feasibility, and costs of real-time polymerase chain reaction (PCR) of nasopharyngeal and oropharyngeal swab specimens in the routine diagnostic work-up for LRTI were determined.

Methods. In a randomized controlled trial, nasopharyngeal and oropharyngeal swab specimens from patients admitted for antibiotic treatment of LRTI were evaluated by means of real-time PCR for respiratory viruses and atypical pathogens, as well as by conventional diagnostic procedures. Real-time PCR results for patients in the intervention group were reported to the treating physician; results for patients in the control group were not made available.

Results. A total of 107 patients (mean age [± standard deviation], 63.6 ± 16.3 years) were included, of whom 55 were allocated to the intervention group. The pathogens detected most frequently were influenza virus (14 patients), Streptococcus pneumoniae (8), coronavirus (6), Staphylococcus aureus (5), and rhinoviruses (5). Real-time PCR increased the diagnostic yield from 23 cases (21% of patients) to 47 cases (43% of patients), compared with conventional diagnostic tests. The detection of viral pathogens by PCR was associated with the winter season, less infiltrates on chest radiographs, lower C-reactive protein levels, and shorter duration of symptoms. Use of real-time PCR results resulted in partial or total cessation of antibiotic treatment for 6 patients (11%; 95% confidence interval, 2–19), but overall antibiotic use was comparable in the intervention group and the control group (median duration of treatment, 10.0 vs. 9.0 days; P = not significant). Use of real-time PCR increased treatment and diagnostic costs with €318.17 per patient.

Conclusions. Implementation of real-time PCR for the etiological diagnosis of LRTI increased the diagnostic yield considerably, but it did not reduce antibiotic use or costs.

Sputum bacteriology in patients with acute exacerbations of COPD in Hong Kong

STUDY OBJECTIVE

To study the demographics and sputum microbiology of patients admitted to a teaching hospital with acute exacerbations of chronic obstructive pulmonary disease (AECOPD).

DESIGN

A retrospective study.

SETTING

A tertiary university hospital in Hong Kong.

PATIENTS

All episodes of AECOPD, patient demographics, length of stay, sputum culture and radiological results admitted in the first half of the year 2000 were retrieved from hospital records.

RESULTS

There were 329 patients with 418 episodes of AECOPD without concomitant pneumonia. The age of the patients was 74.4+/-8.3 years. The acute hospital length of stay for an episode of AECOPD was 7.3+/-6.5 days. Haemophilus influenzae was the commonest organism found in sputum (23.1%), followed by Pseudomonas aeruginosa (6.3%) and Streptococcus pneumoniae (4.0%). Mycobacterium tuberculosis was found in 1.1% of the admissions. Presence of organisms in sputum had no association with the hospital length of stay and intensive care unit admissions. In patients whose FEV1 was >50% of predicted values, there was a higher chance of positive sputum growth of H. influenzae than those with FEV1 <50% (16/44 vs. 31/162 episodes, respectively, P=0.02).

CONCLUSIONS

H. influenzae was the commonest bacterium isolated in sputum in patients with AECOPD. In areas endemic of tuberculosis, it is advisable to use fluoroquinolones for AECOPD with caution.

[Clinical picture and prognostic factors for severe community-acquired pneumonia in adults admitted to the intensive care unit]

OBJECTIVE

In Chile very little information is available on severe community-acquired pneumonia treated in intensive care units. This study describes the clinical picture, prognostic factors, and treatment of adult patients admitted to the intensive care unit for severe community-acquired pneumonia.

PATIENTS AND METHODS

A total of 113 consecutive patients were included in this prospective, descriptive study.

RESULTS

The mean (SD) age of the 113 patients was 73 (15). Of these, 95% had associated comorbidity, and 81% were in the high-risk classes of the Pneumonia Severity Index. Etiology was identified in 31%, and the most common pathogens were Streptococcus pneumoniae (40%), gram negative bacilli (17%), and Mycoplasma pneumoniae (6%). The main complications were the need for mechanical ventilation (45%), septic shock (26%), heart failure (24%), and arrhythmias (15%). Mortality at 30 days was 16.8%, and multivariate analysis revealed the following factors to be associated with a greater risk of death: acute renal failure (odds ratio: 5.1), and glycemia above 300 mg/dL (odds ratio: 7.2).

CONCLUSIONS

The patients with severe pneumonia admitted to the intensive care unit are elderly, with a high level of comorbidity and complications, but most survive.

Validation of the 2001 American Thoracic Society criteria for severe community-acquired pneumonia

STUDY OBJECTIVE

Ewig et al. proposed a new definition of severe community-acquired pneumonia in 1999, which was adopted by the American Thoracic Society in 2001. We evaluated this definition in an independent population of emergency department patients.

DESIGN

We compared the 2001 American Thoracic Society definition of severe community-acquired pneumonia using emergency department data to intensive care unit (ICU) admission, use of mechanical ventilation, and administration of vasopressors.

SETTING

LDS Hospital, a tertiary care, university-affiliated hospital with 520 total beds and 68 ICU beds in Salt Lake City, UT.

PATIENTS

We studied 980 consecutive emergency department patients with a radiographically confirmed diagnosis of pneumonia between June 1995 and June 1999. Of these patients, 498 were admitted to the hospital, immunocompetent, and without a "do-not-resuscitate" order within 24 hrs of admission.

MEASUREMENTS AND MAIN RESULTS

Forty-seven patients met the criteria for severe community-acquired pneumonia in the emergency department and were admitted to the ICU. Three hundred eighty patients did not meet the criteria and were admitted to a hospital unit. Nineteen patients met the definition but were admitted to a hospital unit; only one required subsequent ICU admission. Two of the 19 died after a do-not-resuscitate order was entered >24 hrs after admission; the remainder recovered. Fifty-two patients were triaged to the ICU but did not initially meet the definition of severe pneumonia. Sixteen of these 52 patients required mechanical ventilation, 13 of the 16 within 24 hrs of admission to the ICU. The sensitivity for the 2001 American Thoracic Society definition in our population was 44%, specificity was 95%, positive predictive value was 71%, and negative predictive value was 88%.

CONCLUSION

The 2001 American Thoracic Society definition of severe community-acquired pneumonia had high specificity but lower sensitivity in our population compared with the derivation population. Additional factors not reflected in the definition may contribute to ICU admission and the need for mechanical ventilation.

Recomendações de abordagem diagnóstica e terapêutica da pneumonia da comunidade em adultos imunocompetentes

The Portuguese Respiratory Society makes a series of recommendations as to the state of the art of the diagnostic, therapeutic and preventive approach to community-acquired pneumonia in immunocompetent adults in Portugal. These proposals should be regarded as general guidelines and are not intended to replace the clinical sense used in resolving each individual case. Our main goal is to stratify the patients according to the risk of morbidity and mortality in order to justify the following decisions more rationally: the choice of place of treatment (outpatient or inpatient), diagnostic tests and antimicrobial therapy. We also make a set of recommendations for the prevention of CAP. We plan to conduct multi-centre prospective studies, preferably in collaboration with other scientific societies, in order to be able to characterise the situation in Portugal more accurately and regularly update this document.

Telithromycin in the treatment of community-acquired pneumonia: a pooled analysis

The efficacy of telithromycin has been assessed in six Phase III studies involving adults with mild to moderate community-acquired pneumonia (CAP) with a degree of severity compatible with oral therapy. Patients received telithromycin 800 mg once daily for 7-10 days in three open-label studies (n=870) and three randomized, double-blind, comparator-controlled studies (n=503). Comparator antibacterials were amoxicillin 1000 mg three-times daily, clarithromycin 500 mg twice daily and trovafloxacin 200 mg once daily. Clinical and bacteriological outcomes were assessed 7-14 days post-therapy. Among telithromycin-treated patients, per-protocol clinical cure rates were 93.1 and 91.0% for the open-label and comparative studies, respectively. Telithromycin treatment was as effective as the comparator agents. High eradication and clinical cure rates were observed for infections caused by key pathogens: Streptococcus pneumoniae including isolates resistant to penicillin G and/or erythromycin A (95.4%), Haemophilus influenzae (89.5%) and Moraxella catarrhalis (90%). Telithromycin was also highly effective in patients with infections caused by atypical and/or intracellular pathogens and those at increased risk of morbidity. Telithromycin was generally well tolerated. Telithromycin 800 mg once daily for 7-10 days offers a convenient and well-tolerated first-line oral therapy for the empirical treatment of mild to moderate CAP.

Impaired pulmonary inflammatory responses are a prominent feature of streptococcal pneumonia in mice with experimental emphysema

Little is known about why patients with chronic obstructive pulmonary disease are susceptible to bacterial infections. Using an animal model of pulmonary emphysema, we investigated the inflammatory responses to bacterial infection. After intratracheal infection with Streptococcus pneumoniae (10(3)-10(7) cfu/mouse), the control mice did not die. However, the mice with emphysema died in a dose-dependent manner. Bronchoalveolar lavage fluid, examined 24 hours after infection showed that the numbers of total cells and neutrophils, in addition to murine tumor necrosis factor-alpha and macrophage inflammatory protein-2 concentrations, were significantly less in the mice with emphysema compared with the control mice. Histopathologic findings revealed that the alveoli were filled with inflammatory cells and exudate in the control mice but not in the mice with emphysema. Seventy-two hours after infection, serum cytokine levels were significantly higher in the mice with emphysema, and significant numbers of S. pneumoniae were detected in both the whole lung tissues and the blood of mice with emphysema. These findings suggest that the inflammatory response in mice with emphysema was impaired at the site of bacterial infection despite the bacteremia, which accelerated severe systemic inflammatory responses. Accordingly, intra-alveolar but not systemic immune responses to bacterial infection were impaired in the presence of experimental emphysema.

Prospective epidemiologic survey of patients with community-acquired pneumonia requiring hospitalization in Switzerland

BACKGROUND

Community-acquired pneumonia (CAP) is a common problem and the principal infection requiring hospitalization, but its treatment is complicated by the difficulty in microbiological diagnosis and the increasing incidence of antibiotic resistance among respiratory pathogens. The purpose of this paper is to present the main epidemiologic features of patients with CAP requiring hospitalization in our country.

METHODS

We enrolled three hundred and eighteen adult patients with CAP requiring hospitalization in seven large medical centers in Switzerland during two winter periods. The patients' mean age was 70.4 years. This study describes the epidemiology of these patients. Clinical, radiologic and microbiological evaluations were performed at study entry during treatment, and at 4 weeks post-therapy. For microbiological diagnostic purposes, sputum culture, throat swab culture, PCR, blood cultures, Legionella urinary antigen and serologic evaluations were also performed.

RESULTS

Despite the higher mean age, the overall mortality rate was 8%, lower than in other comparable studies. The most common underlying diseases present at study entry were cardiac failure (23%), chronic obstructive pulmonary disease (20%), renal failure (15%), and diabetes (12%); 40% of the patients were smokers. Although dyspnea, cough and positive pulmonary auscultation findings were present in about 90% of patients, fever >38 degrees C was present in only 64%. The most frequently isolated respiratory pathogens were Streptococcus pneumoniae (12.6%), Haemophilus influenzae (6%), Staphylococcus aureus (1.6%), and Moraxella catarrhalis (1.6%). Atypical pathogens were frequently found, with the following distribution: Mycoplasma pneumoniae, 7.5%; Chlamydia pneumoniae, 5.3%; and Legionella pneumophila, 4.4%. The mean duration between onset of symptoms and hospital admission was 4.8 days, and the mean treatment duration was 12.1 days. Two weeks after the start of therapy, although clinical symptoms were absent, radiologic infiltrates were still present in 24% of patients.

CONCLUSIONS

The microbiological diagnosis in CAP can be established in only about 50% of cases with the combination of several diagnostic tools. Epidemiologic surveys of CAP should be performed on a regular basis, regionally, as a way to improve the management of these infections.

Severe community-acquired pneumonia

Although several pneumonia severity criteria have been firmly established, the exact definition of severe community-acquired pneumonia (CAP) remains elusive. Mortality from CAP remains high, reaching 50% in some series. The particular role of and spp. in severe CAP has been defined more clearly. Microbial diagnosis in the individual patient remains a difficult task. Despite promising new diagnostic tools, concerns about possible mixed origins preclude a change from the currently advocated broad-spectrum approach of antimicrobial treatment. Although there is some evidence that guidelines may optimize outcomes, their role in limiting the spread of resistance has only recently received attention. Finally, although there are promising data on the use of noninvasive positive pressure ventilation to treat pneumonia in patients without chronic obstructive pulmonary disease, its place in the management of acute respiratory failure remains to be defined in randomized studies.

Treatment of community-acquired pneumonia in hospitalised patients

Community-acquired pneumonia (CAP) can be life-threatening. The prognosis is generally poorest in elderly patients and/or those with underlying chronic conditions, but fatalities can occur in all age groups. Current challenges in the clinical management of CAP are discussed, and the criteria for identifying those patients who should be treated in hospital with initial intravenous therapy are considered. Rapid initiation of therapy is important, using an agent that provides coverage against the most likely pathogens--Streptococcus pneumoniae and the atypical organisms. There is an increasing tendency to minimise the duration of intravenous therapy, with an early transition to oral therapy and the rapid return of the patient to the community. The efficacy of oral macrolides in the treatment of CAP is well established. Evidence for the use of intravenous azithromycin to provide effective and well-tolerated, first-line intervention in the hospitalized CAP patient is summarised.

The pulmonary physician in critical care . 3: critical care management of community acquired pneumonia

Severe community acquired pneumonia carries a high mortality. Early recognition of the severity of the illness, rapid and appropriate resuscitation, targeted antibiotic treatment, and the critical care support of multiple failing organ systems are all important in this group of patients. Only by improving all these aspects of care is it likely that survival will increase.

Managing antiinfective therapy of community-acquired pneumonia in the hospital setting: focus on switch therapy

Targeting patients for early switch from intravenous to oral antibiotic therapy and early hospital discharge is an important strategy in the management of community-acquired pneumonia (CAP). This strategy can reduce costs due to drug administration and length of hospital stay. We show that switch therapy can be implemented safely when four criteria are met: cough and respiratory distress improve, fever abates for at least 8 hours, white blood cell count is returning to normal, and patient can take drugs orally In prospective clinical studies conducted at our institution, the clinical cure rate with switch therapy was 99%, and mean length of hospital stay was reduced by more than 2 days. Early switch, coupled with hospital discharge, may be possible in nearly half of all CAP patients. Universal use of switch therapy in the United States could result in the total reduction of about 440,000 hospital days annually and an overall savings of $400 million.

Aspiration pneumonia: dental and oral risk factors in an older veteran population

OBJECTIVES

To investigate the importance of medical and dental factors in aspiration pneumonia in an older veteran population.

DESIGN

Prospective enrollment of subjects with retrospective analysis of data.

SETTING

Department of Veterans Affairs outpatient clinic, inpatient ward, and nursing home.

PARTICIPANTS

358 veterans age 55 and older; 50 subjects with aspiration pneumonia.

MEASUREMENTS

Demographic and medical data; functional status; health-related behaviors; dental care utilization; personal oral hygiene; comprehensive dental examination; salivary assays including IgA antibodies; and cultures of saliva, throat, and dental plaques.

RESULTS

Two logistic regression models produced estimates of significant risk factors. One model using dentate patients included: requiring help with feeding (odds ratio (OR) = 13.9), chronic obstructive pulmonary disease (COPD) (OR = 4.7), diabetes mellitus (OR = 3.5), number of decayed teeth (OR = 1.2), number of functional dental units (OR = 1.2), presence of important organisms for decay, Streptococcus sobrinus in saliva (OR = 6.2), and periodontal disease, Porphyromonous gingivalis in dental plaque (OR = 4.2), and Staphylococcus aureus presence in saliva (OR = 7.4). The second model, containing both dentate and edentulous patients included: requiring help with feeding (OR = 4.7), COPD (OR = 2.5), diabetes mellitus (OR = 1.7), and presence of S. aureus in saliva (OR = 8.3).

CONCLUSION

This study supports the significance of oral and dental factors while controlling for established medical risk factors in aspiration pneumonia incidence.

Radiological-pathological correlation: alveolar pattern

This review summarizes important pathological lesions of the lung that typically present radiographically with an 'alveolar pattern'. For each entity, the latest findings as to its pathogenesis, aetiology and pathology are reviewed in the introductory remarks. We then present the typical radiological appearances alongside macroscopic and microscopic pathological photographs. It is hoped that the parallel presentation of radiological image with the pathology will enhance the understanding of the diverse range of diseases the aevolar pattern comprises.