Community-acquired pneumonia: causes of treatment failure in patients enrolled in clinical trials

Streptococcus pneumoniae favors tolerance via metabolic adaptation over resistance to circumvent fluoroquinolones

Streptococcus pneumoniae is a major human pathogen of global health concern and the rapid emergence of antibiotic resistance poses a serious public health problem worldwide. Fluoroquinolone resistance in S. pneumoniae is an intriguing case because the prevalence of fluoroquinolone resistance does not correlate with increasing usage and has remained rare. Our data indicate that deleterious fitness costs in the mammalian host constrain the emergence of fluoroquinolone resistance both by de novo mutation and recombination. S. pneumoniae was able to circumvent such deleterious fitness costs via the development of antibiotic tolerance through metabolic adaptation that reduced the production of reactive oxygen species, resulting in a fitness benefit during infection of mice treated with fluoroquinolones. These data suggest that the emergence of fluoroquinolone resistance is tightly constrained in S. pneumoniae by fitness tradeoffs and that mutational pathways involving metabolic networks to enable tolerance phenotypes are an important contributor to the evasion of antibiotic-mediated killing.IMPORTANCEThe increasing prevalence of antibiotic resistant bacteria is a major global health concern. While many species have the potential to develop antibiotic resistance, understanding the barriers to resistance emergence in the clinic remains poorly understood. A prime example of this is fluroquinolone resistance in Streptococcus pneumoniae, whereby, despite continued utilization, resistance to this class of antibiotic remains rare. In this study, we found that the predominant pathways for developing resistance to this antibiotic class severely compromised the infectious capacity of the pneumococcus, providing a key impediment for the emergence of resistance. Using in vivo models of experimental evolution, we found that S. pneumoniae responds to repeated fluoroquinolone exposure by modulating key metabolic pathways involved in the generation of redox molecules, which leads to antibiotic treatment failure in the absence of appreciable shifts in resistance levels. These data underscore the complex pathways available to pathogens to evade antibiotic mediating killing via antibiotic tolerance.

Ten Issues for Updating in Community-Acquired Pneumonia: An Expert Review

Community-acquired pneumonia represents the third-highest cause of mortality in industrialized countries and the first due to infection. Although guidelines for the approach to this infection model are widely implemented in international health schemes, information continually emerges that generates controversy or requires updating its management. This paper reviews the most important issues in the approach to this process, such as an aetiologic update using new molecular platforms or imaging techniques, including the diagnostic stewardship in different clinical settings. It also reviews both the Intensive Care Unit admission criteria and those of clinical stability to discharge. An update in antibiotic, in oxygen, or steroidal therapy is presented. It also analyzes the management out-of-hospital in CAP requiring hospitalization, the main factors for readmission, and an approach to therapeutic failure or rescue. Finally, the main strategies for prevention and vaccination in both immunocompetent and immunocompromised hosts are reviewed.

Impact of severe lymphopenia on the early prediction of clinical outcome in hospitalized patients with pneumococcal community-acquired pneumonia

PURPOSE

To evaluate the impact of an optimal and reproducible cutoff value set according to a predefined lymphopenia scale as an early predictor of in-hospital mortality and other outcomes in patients hospitalized with pneumococcal pneumonia and positive urinary antigen at admission to the emergency department.

METHODS

An observational cohort study was conducted based on analysis of a prospective registry of consecutive immunocompetent adults hospitalized for pneumococcal pneumonia in two tertiary hospitals. Generalized additive models were constructed to assess the smooth relationship between in-hospital mortality and lymphopenia.

RESULTS

We included 1173 patients. Lymphopenia on admission was documented in 686 (58.4%). No significant differences were observed between groups regarding the presence of comorbidities. Overall, 299 (25.5%) patients were admitted to intensive care and 90 (7.6%) required invasive mechanical ventilation. Fifty-nine (5%) patients died, among them 23 (38.9%) in the first 72 h after admission. A lymphocyte count < 500/μL, documented in 282 (24%) patients, was the predefined cutoff point that best predicted in-hospital mortality. After adjustment, these patients had higher rates of intensive care admission (OR 2.9; 95% CI 1.9-4.3), invasive mechanical ventilation (OR 2.2; 95% CI 1.2-3.9), septic shock (OR 1.8; 95% CI 1.1-2.9), treatment failure (OR 2.1; 95% CI 1.2-3.5), and in-hospital mortality (OR 2.2; 95% 1.1-4.9). Severe lymphopenia outperformed PSI score in predicting early and 30-day mortality in patients classified in the higher-risk classes.

CONCLUSION

Lymphocyte count < 500/μL could be used as a reproducible predictor of complicated clinical course in patients with an early diagnosis of pneumococcal pneumonia.

A Nomogram for Early Diagnosis of Community-Acquired Pneumonia Based on Bronchoalveolar Lavage Fluid Metabolomics

Purpose

There is a high disease burden associated with community-acquired pneumonia (CAP) around the world. A timely and correct diagnosis of CAP can facilitate early treatment and prevent illness progression. The present study aimed to find some novel biomarkers of CAP by metabolic analysis and construct a nomogram model for precise diagnosis and individualized treatment of CAP patients.

Patients and Methods

42 CAP patients and 20 controls were enrolled in this study. The metabolic profiles of bronchoalveolar lavage fluid (BALF) samples were identified by untargeted LC-MS/MS analysis. With a VIP score ≥ 1 in OPLS-DA analysis and P < 0.05, the significantly dysregulated metabolites were estimated as potential biomarkers of CAP, which were further included in the construction of the diagnostic prediction model along with laboratory inflammatory indexes via stepwise backward regression analysis. Discrimination, calibration, and clinical applicability of the nomogram were evaluated by the C-index, the calibration curve, and the decision curve analysis (DCA) estimated by bootstrap resampling.

Results

The metabolic profiles differed obviously between CAP patients and healthy controls, as shown by PCA and OPLS-DA plots. Seven metabolites significantly dysregulated in CAP were established: dimethyl disulfide, oleic acid (d5), N-acetyl-a-neuraminic acid, pyrimidine, choline, LPC (12:0/0:0) and PA (20:4/2:0). Multivariate logistic regression revealed that the expression levels of PA (20:4/2:0), N-acetyl-a-neuraminic acid, and CRP were associated with CAP. After being validated by bootstrap resampling, this model showed satisfactory diagnostic performance.

Conclusion

A novel nomogram prediction model containing metabolic potential biomarkers in BALF that was developed for the early diagnosis of CAP offers insights into the pathogenesis and host response in CAP.

Quaternized Polysaccharide-Based Cationic Micelles as a Macromolecular Approach to Eradicate Multidrug-Resistant Bacterial Infections while Mitigating Antimicrobial Resistance

Microbial infections and microbial resistance lead to a high demand for new antimicrobial agents. Quaternized polysaccharides are cationic antimicrobial candidates; however, the limitation of homogeneous synthesis solvents that affect the molecular structure and biological activities, as well as their drug resistance remains unclear. Therefore, the authors homogeneously synthesize a series of quaternized chitin (QC) and quaternized chitosan (QCS) derivatives via a green and effective KOH/urea system and investigate their structure-activity relationship and biological activity in vivo and in vitro. Their study reveals that a proper match of degree of quaternization (DQ) and degree of deacetylation (DD') of QC or QCS is key to balance antimicrobial property and cytotoxicity. They identify QCS-2 as the optimized antimicrobial agent with a DQ of 0.46 and DD' of 82%, which exhibits effective broad-spectrum antimicrobial properties, good hemocompatibility, excellent cytocompatibility, and effective inhibition of bacterial biofilm formation and eradication of mature bacterial biofilms. Moreover, QCS-2 exhibits a low propensity for development of drug resistance and significant anti-infective effects on MRSA in vivo comparable to that of vancomycin, avoiding excessive inflammation and promoting the formation of new blood vessels, hair follicles, and collagen deposition to thus expedite wound healing.

Clinical effectiveness of cefoperazone-sulbactam versus piperacillin-tazobactam for the treatment of pneumonia in the elderly population

OBJECTIVES

Both cefoperazone-sulbactam (CFP-SUL) and piperacillin-tazobactam (PIP-TAZ) are β-lactam/β-lactamase inhibitor antibiotics and have a similar antimicrobial spectrum. However, comparative clinical efficacy and safety between CFP-SUL and PIP-TAZ for pneumonia treatment remain largely unknown, especially in the elderly population.

METHODS

Based on a multicenter, registry database, patients aged ≥65, diagnosed with severe community-acquired pneumonia (SCAP), hospital-acquired pneumonia (HAP), or ventilator-associated pneumonia (VAP), and given empirical therapy with CFP-SUL or PIP-TAZ were included for analysis. The primary outcome of interest was the proportion of patients achieving clinical cure. Multivariate logistic regression was conducted to compare the odds ratios (OR) for the outcome between patients received CFP-SUL and PIP-TAZ.

RESULTS

A total of 941 elderly patients, 624 with SCAP and 317 with either HAP or VAP, were included. The overall in-hospital mortality for the entire cohort was 19%. Clinical cure can be achieved in 81% and 83% of patients with SCAP and HAP/VAP, respectively. Multivariate logistic regression analysis showed similar odds for clinical cure between patients receiving CFP-SUL and PIP-TAZ whether they had SCAP (adjusted OR, 1.10; 95% CI, 0.71-1.70) or HAP/VAP (adjusted OR, 0.72; 95% CI, 0.30-1.76). Regarding the safety issue, both CFP-SUL and PIP-TAZ were generally well tolerated with few reported adverse events, even in this aged population.

CONCLUSIONS

Among the elderly patients with SCAP or HAP/VAP, empirical therapy with CFP-SUL is a viable alternative to PIP-TAZ, while considering antibiotic heterogeneity in antimicrobial stewardship.

Factors Associated With Treatment Failure in Moderately Severe Community-Acquired Pneumonia: A Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

Failure of treatment is the most serious complication in community-acquired pneumonia (CAP).

OBJECTIVE

To assess the potential risk factors for treatment failure in clinically stable patients with CAP.

DESIGN, SETTING, AND PARTICIPANTS

This secondary analysis assesses data from a randomized clinical trial on CAP (Pneumonia Short Treatment [PTC] trial) conducted from December 19, 2013, to February 1, 2018. Data analysis was performed from July 18, 2019, to February 15, 2020. Patients hospitalized at 1 of 16 centers in France for moderately severe CAP who were clinically stable at day 3 of antibiotic treatment were included in the PTC trial and analyzed in the per-protocol trial population.

INTERVENTIONS

Patients were randomly assigned (1:1) on day 3 of antibiotic treatment to receive β-lactam (amoxicillin-clavulanate [1 g/125 mg] 3 times daily) or placebo for 5 extra days.

MAIN OUTCOMES AND MEASURES

The main outcome was failure at 15 days after first antibiotic intake, defined as a temperature greater than 37.9 °C and/or absence of resolution or improvement of respiratory symptoms and/or additional antibiotic treatment for any cause. The association among demographic characteristics, baseline clinical and biological variables available (ie, at the first day of β-lactam treatment), and treatment failure at day 15 among the per-protocol trial population was assessed by univariate and multivariable logistic regressions.

RESULTS

Overall, 310 patients were included in the study; this secondary analysis comprised 291 patients (174 [59.8%] male; mean [SD] age, 69.6 [18.5] years). The failure rate was 26.8%. Male sex (odds ratio [OR], 1.74; 95% CI, 1.01-3.07), age per year (OR, 1.03; 95% CI, 1.01-1.05), Pneumonia Severe Index score (OR, 1.01; 95% CI, 1.00-1.02), the presence of chronic lung disease (OR, 1.85; 95% CI, 1.03-3.30), and creatinine clearance (OR, 0.99; 95% CI, 0.98-1.00) were significantly associated with failure in the univariate analysis. When the Pneumonia Severe Index score was excluded to avoid collinearity with age and sex in the regression model, only male sex (OR, 1.92; 95% CI, 1.08-3.49) and age (OR, 1.02; 95% CI, 1.00-1.05) were associated with failure in the multivariable analysis.

CONCLUSIONS AND RELEVANCE

In this secondary analysis of a randomized clinical trial, among patients with CAP who reached clinical stability after 3 days of antibiotic treatment, only male sex and age were associated with higher risk of failure, independent of antibiotic treatment duration and biomarker levels. Another randomized clinical trial is needed to evaluate the impact of treatment duration in populations at higher risk for treatment failure.

Drug use evaluation of cefepime at Khartoum North Teaching Hospital in Sudan

BACKGROUND

Cefepime is essentially used for life-threatening infections. Although overutilisation of antibiotics is strongly discouraged around the world, they are still overused in developing countries including Sudan.

OBJECTIVES

This study aims to evaluate the rational use of cefepime at Khartoum North Teaching Hospital-Sudan.

METHODS

A retrospective cross-sectional, hospital-based study was conducted in the internal medicine ward at Khartoum North Teaching Hospital from August/2018 to April/2019. The study covered medical records of adult patients receiving cefepime during the study period. Patient's data were analysed using simple descriptive statistics (frequency and percentage) and inferential statistics (logistic regression) to describe the relationship between dependent and independent variables. P ≤ .05 was considered statistically significant.

RESULTS

Out of 90 patients, only 16.7% of patients were tested for antibiotic sensitivity. Cefepime was prescribed to 50% and 23.3% of patients for the treatment of UTIs/post-dialysis and sepsis, respectively. Although the majority of patients (72.2%) received cefepime with appropriate indication, only 21.1% and 15.6% received the drug with appropriate dose and duration, respectively. Cefepime had been prescribed appropriately in a correct dose, duration, and indications for only 7.8% of patients. The vast majority of patients tested for kidney functions had elevated creatinine levels (96.1%); however, cefepime dose had been adjusted for only 4.1% of them.

CONCLUSION

This study highlighted the irrational use of cefepime regarding inappropriate dose, duration, and inadequate antibiotic sensitivity tests. A lack of attention to dosage adjustment in patients with renal impairment had been observed. Positive clinical outcome was significantly associated with antibiotic sensitivity test.

Disease burden and prognostic factors for clinical failure in elderly community acquired pneumonia patients

Background

The study was to evaluate initial antimicrobial regimen and clinical outcomes and to explore risk factors for clinical failure (CF) in elderly patients with community-acquired pneumonia (CAP).

Methods

3011 hospitalized elderly patients were enrolled from 13 national teaching hospitals between January 1, 2014 and December 31, 2014 initiated by the CAP-China network. Risk factors for CF were screened by multivariable logistic regression analysis.

Results

The incidence of CF in elderly CAP patients was 13.1%. CF patients were older, longer hospital stays and higher treatment costs than clinical success (CS) patients. The CF patients were more prone to present hyperglycemia, hyponatremia, hypoproteinemia, pleural effusion, respiratory failure and cardiovascular events. Inappropriate initial antimicrobial regimens in CF group were significantly higher than CS group. Undertreatment, CURB-65, PH < 7.3, PaO₂/FiO₂ < 200 mmHg, sodium < 130 mmol/L, healthcare-associated pneumonia, white blood cells > 10,000/mm³, pleural effusion and congestive heart failure were independent risk factors for CF in multivariable logistic regression analysis. Male and bronchiectasis were protective factors.

Conclusions

Discordant therapy was a cause of CF. Early accurate detection and management of prevention to potential causes is likely to improve clinical outcomes in elderly patients CAP.

Trial registration

A Retrospective Study on Hospitalized Patients With Community-acquired Pneumonia in China (CAP-China) (RSCAP-China), NCT02489578. Registered 16 March 2015, https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S0005E5S&selectaction=Edit&uid=U0000GWC&ts=2&cx=1bnotb

[Guidelines for the Management of Community Acquired Pneumonia in Children and Adolescents (Pediatric Community Acquired Pneumonia, pCAP) - Issued under the Responsibility of the German Society for Pediatric Infectious Diseases (DGPI) and the German Society for Pediatric Pulmonology (GPP)]

The present guideline aims to improve the evidence-based management of children and adolescents with pediatric community-acquired pneumonia (pCAP). Despite a prevalence of approx. 300 cases per 100 000 children per year in Central Europe, mortality is very low. Prevention includes infection control measures and comprehensive immunization. The diagnosis can and should be established clinically by history, physical examination and pulse oximetry, with fever and tachypnea as cardinal features. Additional signs or symptoms such as severely compromised general condition, poor feeding, dehydration, altered consciousness or seizures discriminate subjects with severe pCAP from those with non-severe pCAP. Within an age-dependent spectrum of infectious agents, bacterial etiology cannot be reliably differentiated from viral or mixed infections by currently available biomarkers. Most children and adolescents with non-severe pCAP and oxygen saturation > 92 % can be managed as outpatients without laboratory/microbiology workup or imaging. Anti-infective agents are not generally indicated and can be safely withheld especially in children of young age, with wheeze or other indices suggesting a viral origin. For calculated antibiotic therapy, aminopenicillins are the preferred drug class with comparable efficacy of oral (amoxicillin) and intravenous administration (ampicillin). Follow-up evaluation after 48 - 72 hours is mandatory for the assessment of clinical course, treatment success and potential complications such as parapneumonic pleural effusion or empyema, which may necessitate alternative or add-on therapy.

A boronic acid-functionalized phthalocyanine with an aggregation-enhanced photodynamic effect for combating antibiotic-resistant bacteria

Most existing photosensitizers (e.g., porphyrins) are often aggregated in aqueous solution because of their large conjugated molecular structures. This aggregation usually results in a lack or low levels of reactive oxygen species (ROS) generation due to aggregation-caused quenching, which severely hampers the application of photosensitizers in photodynamic therapy (PDT). Herein, we make an interesting finding that a boronic acid-functionalized phthalocyanine (PcN4-BA) displays an uncommon phenomenon, an aggregation-enhanced photodynamic effect. The combination of the ability to form uniform nanostructured self-assemblies in water, highly efficient ROS generation and boronic acid-induced targeting give PcN4-BA excellent performances in antimicrobial PDT.

Antibiotic Use and Outcomes in Children in the Emergency Department With Suspected Pneumonia

BACKGROUND AND OBJECTIVES

Antibiotic therapy is often prescribed for suspected community-acquired pneumonia (CAP) in children despite a lack of knowledge of causative pathogen. Our objective in this study was to investigate the association between antibiotic prescription and treatment failure in children with suspected CAP who are discharged from the hospital emergency department (ED).

METHODS

We performed a prospective cohort study of children (ages 3 months-18 years) who were discharged from the ED with suspected CAP. The primary exposure was antibiotic receipt or prescription. The primary outcome was treatment failure (ie, hospitalization after being discharged from the ED, return visit with antibiotic initiation or change, or antibiotic change within 7-15 days from the ED visit). The secondary outcomes included parent-reported quality-of-life measures. Propensity score matching was used to limit potential bias attributable to treatment selection between children who did and did not receive an antibiotic prescription.

RESULTS

Of 337 eligible children, 294 were matched on the basis of propensity score. There was no statistical difference in treatment failure between children who received antibiotics and those who did not (odds ratio 1.0; 95% confidence interval 0.45-2.2). There was no difference in the proportion of children with return visits with hospitalization (3.4% with antibiotics versus 3.4% without), initiation and/or change of antibiotics (4.8% vs 6.1%), or parent-reported quality-of-life measures.

CONCLUSIONS

Among children with suspected CAP, the outcomes were not statistically different between those who did and did not receive an antibiotic prescription.

A Supramolecular-Based Dual-Wavelength Phototherapeutic Agent with Broad-Spectrum Antimicrobial Activity Against Drug-Resistant Bacteria

With the ever-increasing threat posed by the multi-drug resistance of bacteria, the development of non-antibiotic agents for the broad-spectrum eradication of clinically prevalent superbugs remains a global challenge. Here, we demonstrate the simple supramolecular self-assembly of structurally defined graphene nanoribbons (GNRs) with a cationic porphyrin (Pp4N) to afford unique one-dimensional wire-like GNR superstructures coated with Pp4N nanoparticles. This Pp4N/GNR nanocomposite displays excellent dual-modal properties with significant reactive-oxygen-species (ROS) production (in photodynamic therapy) and temperature elevation (in photothermal therapy) upon light irradiation at 660 and 808 nm, respectively. This combined approach proved synergistic, providing an impressive antimicrobial effect that led to the complete annihilation of a wide spectrum of Gram-positive, Gram-negative, and drug-resistant bacteria both in vitro and in vivo. The study also unveils the promise of GNRs as a new platform to develop dual-modal antimicrobial agents that are able to overcome antibiotic resistance.

Biomarkers and clinical scoring systems in community-acquired pneumonia

Community-acquired pneumonia (CAP) is the third most common cause of death globally. Due to the complexity of CAP, it is widely accepted that, currently, clinical prognosis and diagnosis is inadequate for the assessment of the severity of the disease. With the aim to determining the initial treatment and the appropriate level of intervention, several clinical scores of severity and biomarkers have been developed. Both biomarkers and clinical scoring systems are expected to determine the different aspects of the host factor and the response to therapy, in order for physicians to be able to make an accurate benefit/risk assessment that will lead to proper diagnosis and correct prescription of antibiotics. This review aims to highlight the prognostic and diagnostic accuracy of various laboratory and clinical parameters in CAP and discuss the perspectives for the reduction of CAP mortality.

Biomarkers in Pneumonia-Beyond Procalcitonin

Pneumonia is the leading infectious cause of mortality worldwide and one of the most common lower respiratory tract infections that is contributing significantly to the burden of antibiotic consumption. Due to the complexity of its pathophysiology, it is widely accepted that clinical diagnosis and prognosis are inadequate for the accurate assessment of the severity of the disease. The most challenging task for a physician is the risk stratification of patients with community-acquired pneumonia. Herein, early diagnosis is essential in order to reduce hospitalization and mortality. Procalcitonin and C-reactive protein remain the most widely used biomarkers, while interleukin 6 has been of particular interest in the literature. However, none of them appear to be ideal, and the search for novel biomarkers that will most sufficiently predict the severity and treatment response in pneumonia has lately intensified. Although our insight has significantly increased over the last years, a translational approach with the application of genomics, metabolomics, microbiomics, and proteomics is required to better understand the disease. In this review, we discuss this rapidly evolving area and summarize the application of novel biomarkers that appear to be promising for the accurate diagnosis and risk stratification of pneumonia.

Measurement of selected preventable adverse drug events in electronic health records: Toward developing a complexity score

PURPOSE

The defining of a select number of high-priority preventable adverse drug events (pADEs) for measurement in the electronic health record (EHR) and the estimation of pADE incidences in two tertiary care facilities are described.

METHODS

This study was part of a larger effort aimed at developing an automated electronic health record (EHR)-based complexity-score (C-score) that ranks hospitalized patients according to their risk for pADEs for clinical intervention. We developed measures for 16 high-priority pADEs often deemed preventable using discrete clinical and administrative EHR data. For each pADE we specified inclusion and exclusion criteria that were used to define risk populations for each specific pADE. The incidence of each type of pADE was then measured during a designated follow-up period considering all adult admissions to 2 large academic tertiary care hospitals, who were eligible for the pADE-specific risk populations during any of their first 5 hospital days.

RESULTS

Utilizing the data from 83,787 admissions who were at risk for at least one pADE during at least one of their first five hospital days, we found that 27,193 admissions (32.5%) developed at least one pADE. Uncontrolled postsurgical pain, uncontrolled pneumonia, and drug-associated hypotension had the highest incidences with the following number of days with pADE per number of patients at risk: 13,484 of 19,640; 527 of 1,530; and 13,394 of 43,630, while drug-associated falls (446 of 75,036), drug-associated acute mental status changes (262 of 66,875) and venous thromboembolism (214 of 74,283) had the lowest incidence rates.

CONCLUSION

EHR-based definitions of clinically important pADEs were developed, and the incidence of the pADEs was estimated. These definitions will be advanced for the creation of prediction models to develop a C-score for identifying patients at risk for pADEs to prioritize pharmacist intervention.

Predictors of treatment failure and clinical stability in patients with community acquired pneumonia

Community acquired pneumonia (CAP) is the leading infectious cause of mortality worldwide with approximately 10% of patients hospitalized requiring intensive care unit (ICU) admission. The ability to predict clinical stability (CS) and treatment failure (TF) enables the clinician to alter antibiotics appropriately, facilitate a timely ICU admission, or arrange a suitable discharge. The detection of CS and TF can be difficult and changes in clinical signs may be subtle or delayed. Thus clinical scores and biomarkers are routinely used to identify severity and monitor clinical progression. The evidence, however, is vast and the definitive role of these systems is at times difficult to elucidate. The aim of this review is to analyse the current literature and to provide a rational and clinically focused view of the predictive utility of various systems used to identify CS and TF in CAP.

The management of community-acquired pneumonia in infants and children older than 3 months of age: clinical practice guidelines by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America

Evidenced-based guidelines for management of infants and children with community-acquired pneumonia (CAP) were prepared by an expert panel comprising clinicians and investigators representing community pediatrics, public health, and the pediatric specialties of critical care, emergency medicine, hospital medicine, infectious diseases, pulmonology, and surgery. These guidelines are intended for use by primary care and subspecialty providers responsible for the management of otherwise healthy infants and children with CAP in both outpatient and inpatient settings. Site-of-care management, diagnosis, antimicrobial and adjunctive surgical therapy, and prevention are discussed. Areas that warrant future investigations are also highlighted.

Biomarkers in the management of pneumonia

A novel approach to improve diagnosis and prognosis of pneumonia is the use of biomarkers. An ideal diagnostic biomarker for pneumonia should allow an early diagnosis and differential diagnosis from other, noninfectious conditions. Procalcitonin (PCT) has emerged as a reliable diagnostic marker in pneumonia, and is better when compared with other markers, namely C-reactive protein, leukocyte count and proinflammatory cytokines. A PCT-based diagnostic and therapeutic strategy can reduce antibiotic usage in patients with pneumonia, mainly by reducing the duration of antibiotic courses. However, PCT should not be used as a substitute for a careful clinical assessment. PCT levels may remain low in localized infections in the context of pneumonia, especially in patients with localized empyema. An ideal prognostic biomarker should be informative about the course and outcome of a disease. Various biomarkers, namely pro-adrenomedullin, natriuretic peptides, endothelin-1 precursor peptides, as well as copeptin and cortisol levels, are promising in this respect. Future studies will show whether an assessment with those novel biomarkers is able to guide prognostic decision-making and improve the allocation of healthcare resources and hospitalization costs.

Procalcitonin and pneumonia: is it a useful marker?

An ideal biomarker for pneumonia should allow an early diagnosis and differential diagnosis from noninfectious conditions and should inform about the course and prognosis of the disease. Procalcitonin (PCT) covers these features better as compared to more commonly used biomarkers like C-reactive protein or leukocyte count. PCT complements and improves the assessment of pneumonia based on careful patient history, dedicated physical examination, and appropriate cultures. Importantly, a PCT-based therapeutic strategy can safely and markedly reduce antibiotic courses in community-acquired pneumonia. However, as is the cast with all diagnostic surrogate markers, PCT can be increased in noninfectious conditions and may remain low in bacterial infections, especially localized infections. This stresses the importance of follow-up measurements, because PCT levels in these patients often show a gradual increase during follow-up. Although PCT is -better than more common biomarkers for the prognosis of pneumonia and to predict survival and outcome, novel biomarkers show an even better prognostic accuracy.

[Severe form of Legionnaires' disease in an immunocompetent patient]

BACKGROUND

Legionnaires' disease (LD) is a pneumonia caused by Legionella pneumophila (LP). The disease occurs more often in immunocompromised persons and can be manifested by severe pneumonia, multiple organ failure and has a high mortality.

CASE REPORT

Immunocompetent patient, male, 53-year old, with severe form of LB had fever, cough, weakness and diarrhea as the initial symptoms of the disease. Laboratory results showed increased number of leukocytes, increased values of acute phase proteins, liver enzymes and hyponatremia. Computed tomography of the chest showed the marked inflammatory lessions on both sides. Pathohistological analysis of the samples retrieved by bronchoscopy pointed to a pneumonia, and diagnosis of LD was confirmed by positive urine test for LP antigen. Later, the disease was complicated by acute adult respiratory distress syndrome (ARDS). Treatment with antibiotics (erythromycin, rifampicin, azithromycin) combined with ARDS treatment led to a clinical recovery of the patient together with complete resolution of inflammatory lesions seen on chest radiography.

CONCLUSION

In severe pneumonias it is necessary to consider LD in differential diagnosis, perform tests with aim of detecting LP and apply adequate antibiotic treatment in order to accomplish positive outcome of the therapy and prevent complications.

Measuring acceptable treatment failure rates for community-acquired pneumonia: potential for reducing duration of treatment and antimicrobial resistance

OBJECTIVE

This study was designed to establish the rates of treatment failure for community-acquired pneumonia that are acceptable to knowledgeable and experienced physicians, in order to facilitate the interpretation of existing studies and the design of new studies aimed at optimizing the duration of antibiotic therapy. Reducing the duration of antibiotic therapy is one strategy for reducing antibiotic exposure and thereby minimizing the potential for the emergence of antimicrobial resistance.

DESIGN

Survey soliciting the acceptable failure rate for treatment given to an adult patient with uncomplicated community-acquired pneumonia treated with standard-of-care therapy in the outpatient setting. Analysis was performed using a modification of established methods of contingent valuation analysis.

PARTICIPANTS

Six hundred eighty infectious diseases physicians in North America who were also members of the Emerging Infections Network of the Infectious Diseases Society of America.

RESULTS

Three hundred seventy-five (55.1%) of 680 physicians responded to the survey. The median acceptable failure rate for treatment was 13.5%. Five hundred ten respondents (75.0%) found a failure rate of 7.3% acceptable, and 170 respondents (25.0%) found a failure rate of 19.8% acceptable.

CONCLUSIONS

This study identified the failure rates for treatment of community-acquired pneumonia that were acceptable to infectious disease physicians. This range of acceptable treatment failure rates may facilitate the design of studies aimed at optimizing the duration of antimicrobial therapy for community-acquired pneumonia.

Predictive value of serial measurements of sTREM-1 in the treatment response of patients with community-acquired pneumonia

BACKGROUND/PURPOSE

To evaluate the roles of plasma sTREM-1 (soluble triggering receptor expressed on myeloid cells-1) and C-reactive protein (CRP) in predicting treatment response in patients with community-acquired pneumonia (CAP).

METHODS

Patients with CAP were enrolled prospectively at a medical center in central Taiwan from September 1, 2004 to July 31, 2005. They were treated according to the guidelines proposed by the American Thoracic Society. Patients were noted as nonresponsive to initial treatment if they had one of the following: persistent fever for more than 3 days, progression on chest radiograph, switching to other antibiotics, or need of mechanical ventilation and/or chest tube drainage.

RESULTS

Fifty-eight patients (43 males/15 females; mean age, 67 +/- 21 years) with CAP were enrolled. Twelve (12/58, 21%) were nonresponsive. In the response group, CRP was reduced up to 58% from day 1 to day 3 (from 18.8 to 7.8 mg/dL), whereas sTREM-1 was reduced by only 15% (from 32.8 to 28.1 pg/mL). In the nonresponse group, CRP still declined 20% (from 22.2 to 17.7 mg/dL), whereas sTREM-1 was persistently high (from 61.7 to 63.7 pg/mL). Using multivariate logistic regression analysis, both CRP (p = 0.006) and sTREM-1 (p = 0.046) on day 3 predicted treatment response significantly, but CRP on day 3 had stronger statistic power.

CONCLUSION

Both CRP and sTREM-1 on day 3 could be useful in predicting nonresponsive CAP patients. Differential trends between sTREM-1 and CRP in nonresponsive CAP suggest that sTREM-1 could be an adjuvant biomarker to CRP in predicting CAP patients without response to empiric treatment.

Diagnostic and prognostic accuracy of clinical and laboratory parameters in community-acquired pneumonia

Background

Community-acquired pneumonia (CAP) is the most frequent infection-related cause of death. The reference standard to diagnose CAP is a new infiltrate on chest radiograph in the presence of recently acquired respiratory signs and symptoms. This study aims to evaluate the diagnostic and prognostic accuracy of clinical signs and symptoms and laboratory biomarkers for CAP.

Methods

545 patients with suspected lower respiratory tract infection, admitted to the emergency department of a university hospital were included in a pre-planned post-hoc analysis of two controlled intervention trials. Baseline assessment included history, clinical examination, radiography and measurements of procalcitonin (PCT), highly sensitive C-reactive protein (hsCRP) and leukocyte count.

Results

Of the 545 patients, 373 had CAP, 132 other respiratory tract infections, and 40 other final diagnoses. The AUC of a clinical model including standard clinical signs and symptoms (i.e. fever, cough, sputum production, abnormal chest auscultation and dyspnea) to diagnose CAP was 0.79 [95% CI, 0.75–0.83]. This AUC was significantly improved by including PCT and hsCRP (0.92 [0.89–0.94]; p < 0.001). PCT had a higher diagnostic accuracy (AUC, 0.88 [0.84–0.93]) in differentiating CAP from other diagnoses, as compared to hsCRP (AUC, 0.76 [0.69–0.83]; p < 0.001) and total leukocyte count (AUC, 0.69 [0.62–0.77]; p < 0.001). To predict bacteremia, PCT had a higher AUC (0.85 [0.80–0.91]) as compared to hsCRP (p = 0.01), leukocyte count (p = 0.002) and elevated body temperature (p < 0.001). PCT, in contrast to hsCRP and leukocyte count, increased with increasing severity of CAP, as assessed by the pneumonia severity index (p < 0.001).

Conclusion

PCT, and to a lesser degree hsCRP, improve the accuracy of currently recommended approaches for the diagnosis of CAP, thereby complementing clinical signs and symptoms. PCT is useful in the severity assessment of CAP.

Biochemical and immunologic features of an outbreak of Legionnaires disease: comparative study between community-acquired pneumonias

Legionella pneumophila has been recognized as an important cause of community- and hospital-acquired pneumonia. This study evaluates the interrelationship between that patients group with Legionnaires disease (LD) and the possible factors that may predispose hosts to acquire this infection. Likewise, we search for preliminary biochemical and immunologic evidences that could help physicians to differentiate between LD and other pneumonias. We analyzed biochemical parameters and immunoglobulin levels in 61 LD patients and a control group (n = 30) who were non-Legionella pneumonia diagnosed. We observed statistically significant differences in LD patients versus control group in serum sodium, albumin, gamma-band, IgG levels, (P < .01) and for total proteins, aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) (P < .05). Our study shows a trend between the presence of LD and immunoglobulin deficiencies in the group studied. Deficit in IgG or IgG plus IgM, during the exposure period, may predispose individuals to suffer legionellosis (P < .05). Overall, hypoalbuminemia, hyponatremia, and high AST and LDH levels can represent a useful prognostic marker in patients with severe pulmonary infection suspected to be legionellosis.

Procalcitonin Guidance of Antibiotic Therapy in Community-acquired Pneumonia

RATIONALE

In patients with community-acquired pneumonia, guidelines recommend antibiotic treatment for 7 to 21 d. Procalcitonin is elevated in bacterial infections, and its dynamics have prognostic implications.

OBJECTIVE

To assess procalcitonin guidance for the initiation and duration of antibiotic therapy in community-acquired pneumonia.

METHODS

In a randomized intervention trial, 302 consecutive patients with suspected community-acquired pneumonia were included. Data were assessed at baseline, after 4, 6, and 8 d, and after 6 wk. The control group (n = 151) received antibiotics according to usual practice. In the procalcitonin group (n = 151), antibiotic treatment was based on serum procalcitonin concentrations as follows: strongly discouraged, less than 0.1 microg/L; discouraged, less than 0.25 microg/L; encouraged, greater than 0.25 microg/L; strongly encouraged, greater than 0.5 microg/L. The primary endpoint was antibiotic use; secondary endpoints were measures of clinical, laboratory, and radiographic outcome.

RESULTS

At baseline, both groups were similar regarding clinical, laboratory, and microbiology characteristics, and Pneumonia Severity Index. Procalcitonin guidance reduced total antibiotic exposure (relative risk, 0.52; 95% confidence interval, 0.48-0.55; p < 0.001), antibiotic prescriptions on admission (85 vs. 99%; p < 0.001), and antibiotic treatment duration (median, 5 vs. 12 d; p < 0.001) compared with patients treated according to guidelines. After adjustment for Pneumonia Severity Index, the hazard ratio of antibiotic discontinuation was higher in the procalcitonin group than in the control group (3.2; 95% confidence interval, 2.5 to 4.2). Outcome was similar in both groups, with an overall success rate of 83%.

CONCLUSIONS

Procalcitonin guidance substantially reduces antibiotic use in community-acquired pneumonia. These findings may have important clinical and public health implications.

Analysis of factors that contribute to treatment failure in patients with community-acquired pneumonia

To determine the causes of treatment failure and to evaluate the prognostic factors in patients hospitalized for community-acquired pneumonia, a prospective, observational study of 228 adult patients hospitalized for a community-acquired pneumonia in the University Hospital of Geneva and the La Chaux-de-Fonds Community Hospital, Switzerland, was conducted. The percentage of patients who failed to improve (as defined by guidelines of the Infectious Disease Society of America) and the causes of treatment failure were assessed, and patients who failed to improve under antimicrobial therapy were compared with those who did improve. In the 54 (24%) patients who failed to improve, a mean increase in length of hospitalization of 4 days was observed. Most causes of treatment failure could be attributed to host factors (61%) rather than to the pathogen (16%) or to an inappropriate antibiotic regimen (3%). After adjusting for potentially confounding variables, concomitant neoplasia (OR 3.25; 95%CI 1.11-9.56), neurological disease (OR 2.34; 95%CI 1.07-5.13), and aspiration pneumonia (OR 2.97; 95%CI 29-6.86]) were associated with failure to improve, whereas monocytosis improved prognosis (OR 0.40; 95%CI 0.20-0.80). Almost one out of four patients hospitalized for community-acquired pneumonia failed to respond to empirical antibiotic treatment. Aspiration pneumonia, concomitant neoplasia, and neurological disease were factors positively associated with failure to improve, whereas monocytosis was linked to a better prognosis.

Treatment with Sequential Intravenous or Oral Moxifloxacin Was Associated with Faster Clinical Improvement than Was Standard Therapy for Hospitalized Patients with Community-Acquired Pneumonia Who Received Initial Parenteral Therapy

BACKGROUND

Although third-generation cephalosporins, such as ceftriaxone (CTRX), and pneumococcal fluoroquinolones, such as moxifloxacin (MXF), are currently recommended first-line antibiotics for empirical treatment of inpatients with community-acquired pneumonia, CTRX and MXF have never undergone a head-to-head comparison. We therefore compared the efficacy, safety, and speed and quality of defervescence of sequential intravenous or oral MXF and high-dose CTRX with or without erythromycin (CTRX+/-ERY) for patients with community-acquired pneumonia requiring parenteral therapy.

METHODS

In this prospective, multicenter, randomized, controlled, nonblinded study, 397 patients were randomly assigned to receive either MXF (400 mg once daily intravenously, possibly followed by oral tablets) or CTRX (2 g intravenously once daily) with or without ERY (1 g intravenously every 6-8 h) for 7-14 days.

RESULTS

Among 317 patients evaluable for efficacy and safety, 138 (85.7%) of 161 MXF-treated patients and 135 (86.5%) of 156 CTRX+/-ERY-treated patients (59 [37.8%] of whom received CTRX and ERY) achieved continued clinical resolution. Defervescence and relief of symptoms, such as chest pain, occurred significantly earlier in the MXF-treated group than in the CTRX+/-ERY-treated group. Both regimens were generally well tolerated.

CONCLUSIONS

For adult patients hospitalized with community-acquired pneumonia, sequential MXF therapy was clinically equivalent to high-dose CTRX+/-ERY therapy but led to a faster clinical improvement.

Nonresponses and treatment failures with conventional empiric regimens in patients with community-acquired pneumonia

Although most patients with suspected CAP respond to empiric therapy,a small number of patients do not respond in the expected fashion. Age and underlying comorbid conditions have a strong influence on the course of illness. Less common causes of treatment failures include overwhelming infection, antimicrobial resistance, and misdiagnosis. It is a common practice for empiric antimicrobial treatment of CAP to be initiated without microbiologic studies. Clinicians carefully should observe these patients for unusual or slow responses and should be ready to pursue a more extensive search for the cause of treatment failure.