Macrolides for better resolution of community-acquired pneumonia: A global meta-analysis of clinical outcomes with focus on microbial aetiology

OBJECTIVES

This meta-analysis examined the effect of macrolides on resolution of community-acquired pneumonia (CAP) and interpretation of clinical benefit according to microbiology; emphasis is given to data under-reported countries (URCs).

METHODS

This meta-analysis included 47 publications published between 1994 and 2022. Publications were analysed for 30-d mortality (58 759 patients) and resolution of CAP (6465 patients). A separate meta-analysis was done for the prevalence of respiratory pathogens in URCs.

RESULTS

Mortality after 30 d was reduced by the addition of macrolides (odds ratio [OR] 0.65, 95% confidence interval [CI] 0.51-0.82). The OR for CAP resolution when macrolides were added to the treatment regimen was 1.23 (95% CI 1.00-1.52). In the CAP resolution analysis, the most prevalent pathogen was Streptococcus pneumoniae (12.68%; 95% CI 9.36-16.95%). Analysis of the pathogen epidemiology from the URCs included 12 publications. The most prevalent pathogens were S. pneumoniae (24.91%) and Klebsiella pneumoniae (12.90%).

CONCLUSION

The addition of macrolides to the treatment regimen led to 35% relative decrease of 30-d mortality and to 23% relative increase in resolution of CAP.

[Management of Adult Community-Acquired Pneumonia and Prevention - Update 2021 - Guideline of the German Respiratory Society (DGP), the Paul-Ehrlich-Society for Chemotherapy (PEG), the German Society for Infectious Diseases (DGI), the German Society of Medical Intensive Care and Emergency Medicine (DGIIN), the German Viological Society (DGV), the Competence Network CAPNETZ, the German College of General Practitioneers and Family Physicians (DEGAM), the German Society for Geriatric Medicine (DGG), the German Palliative Society (DGP), the Austrian Society of Pneumology Society (ÖGP), the Austrian Society for Infectious and Tropical Diseases (ÖGIT), the Swiss Respiratory Society (SGP) and the Swiss Society for Infectious Diseases Society (SSI)]

The present guideline provides a new and updated concept of the management of adult patients with community-acquired pneumonia. It replaces the previous guideline dating from 2016.The guideline was worked out and agreed on following the standards of methodology of a S3-guideline. This includes a systematic literature search and grading, a structured discussion of recommendations supported by the literature as well as the declaration and assessment of potential conflicts of interests.The guideline has a focus on specific clinical circumstances, an update on severity assessment, and includes recommendations for an individualized selection of antimicrobial treatment.The recommendations aim at the same time at a structured assessment of risk for adverse outcome as well as an early determination of treatment goals in order to reduce mortality in patients with curative treatment goal and to provide palliation for patients with treatment restrictions.

Procalcitonin (PCT)-guided antibiotic stewardship in Asia-Pacific countries: adaptation based on an expert consensus meeting

Introduction Recently, an expert consensus on optimal use of procalcitonin (PCT)-guided antibiotic stewardship was published focusing mainly on Europe and the United States. However, for Asia-Pacific countries, recommendations may need adaptation due to differences in types of infections, available resources and standard of clinical care. Methods Practical experience with PCT-guided antibiotic stewardship was discussed among experts from different countries, reflecting on the applicability of the proposed Berlin consensus algorithms for Asia-Pacific. Using a Delphi process, the group reached consensus on two PCT algorithms for the critically ill and the non-critically ill patient populations. Results The group agreed that the existing evidence for PCT-guided antibiotic stewardship in patients with acute respiratory infections and sepsis is generally valid also for Asia-Pacific countries, in regard to proposed PCT cut-offs, emphasis on diagnosis, prognosis and antibiotic stewardship, overruling criteria and inevitable adaptations to clinical settings. However, the group noted an insufficient database on patients with tropical diseases currently limiting the clinical utility in these patients. Also, due to lower resource availabilities, biomarker levels may be measured less frequently and only when changes in treatment are highly likely. Conclusions Use of PCT to guide antibiotic stewardship in conjunction with continuous education and regular feedback to all stakeholders has high potential to improve the utilization of antibiotic treatment also in Asia-Pacific countries. However, there is need for adaptations of existing algorithms due to differences in types of infections and routine clinical care. Further research is needed to understand the optimal use of PCT in patients with tropical diseases.

Pneumococal community-acquired pneumonia in the intensive care unit: Azithromycin remains protective despite macrolide resistance

BACKGROUND

Streptococcus pneumoniae (SP) remains the leading pathogen in community-acquired pneumonia (CAP). Despite the increasing prevalence of macrolide resistance in SP, guidelines recommend the use of macrolides as part of a combination regiment for intensive care unit (ICU) patients with CAP. We sought to describe if macrolide resistance effects outcomes in SP CAP in the ICU and if macrolides remain associated with a mortality advantage in an era of greater resistance.

METHODS

We identified all patients with SP CAP admitted to the ICU between January 2012 and December 2016, and hospital mortality represented the primary endpoint. We recorded markers of acute and chronic disease severity (eg, Charlson score, need for mechanical ventilation and/or vasopressors) along with infection-related variables including the presence of macrolide resistance. We compared subjects treated with azithromycin to those not given this agent.

RESULTS

The cohort included 140 subjects (89.2% on mechanical ventilation, 14.3% crude mortality). Macrolide resistance occurred often (60.8%) and, in univariate analyses, was associated with higher mortality while azithromycin use appeared linked to fewer death. In multivariate analysis controlling for multiple confounders including macrolide resistance and the timeliness and appropriateness of antibiotic therapy, treatment with azithromycin resulted in fewer death (Adjusted odds ratio 0.27, 95% confidence interval: 0.09-0.85, p = 0.024). Macrolide resistance, however, was not independently related to mortality.

CONCLUSIONS

Macrolide resistance appears frequently in SP ICU CAP. The addition of azithromycin to the antibiotic regimen in this scenario is significantly associated with a reduction in in-hospital mortality independent of multiple co-variates.

Procalcitonin (PCT)-guided antibiotic stewardship: an international experts consensus on optimized clinical use

Background Procalcitonin (PCT)-guided antibiotic stewardship (ABS) has been shown to reduce antibiotics (ABxs), with lower side-effects and an improvement in clinical outcomes. The aim of this experts workshop was to derive a PCT algorithm ABS for easier implementation into clinical routine across different clinical settings. Methods Clinical evidence and practical experience with PCT-guided ABS was analyzed and discussed, with a focus on optimal PCT use in the clinical context and increased adherence to PCT protocols. Using a Delphi process, the experts group reached consensus on different PCT algorithms based on clinical severity of the patient and probability of bacterial infection. Results The group agreed that there is strong evidence that PCT-guided ABS supports individual decisions on initiation and duration of ABx treatment in patients with acute respiratory infections and sepsis from any source, thereby reducing overall ABx exposure and associated side effects, and improving clinical outcomes. To simplify practical application, the expert group refined the established PCT algorithms by incorporating severity of illness and probability of bacterial infection and reducing the fixed cut-offs to only one for mild to moderate and one for severe disease (0.25 μg/L and 0.5 μg/L, respectively). Further, guidance on interpretation of PCT results to initiate, withhold or discontinue ABx treatment was included. Conclusions A combination of clinical patient assessment with PCT levels in well-defined ABS algorithms, in context with continuous education and regular feedback to all ABS stakeholders, has the potential to improve the diagnostic and therapeutic management of patients suspected of bacterial infection, thereby improving ABS effectiveness.

Outcomes of Macrolide Deescalation in Severe Community-acquired Pneumonia

PURPOSE

Current data suggest potential benefits with β-lactam plus macrolide combination therapy for empiric treatment of intensive care unit (ICU) patients with severe community-acquired pneumonia (CAP). However, it is unclear whether deescalation to β-lactam monotherapy in the absence of positive results on diagnostic tests, such as the BioFire FilmArray Respiratory Panel 2 (BioFire polymerase chain reaction [PCR]), affects clinical outcomes. The purpose of this study was to compare outcomes between patients with negative BioFire PCR results deescalated to β-lactam monotherapy with those not deescalated.

METHODS

This single-center, retrospective cohort study assessed the in-hospital mortality rates of critically ill adults with CAP treated for ≥48 h with combination β-lactam and azithromycin therapy. Additional end points included hospital length of stay (LOS), ICU LOS, duration of mechanical ventilatory support, 30-day readmission, and incidence of azithromycin-related adverse effects.

FINDINGS

A total of 94 patients were included: 53 in the deescalation group and 41 in the nondeescalation group. No difference was observed with respect to in-hospital mortality (2.4% vs 11.3%, P = 0.312), although patients in the deescalated group experienced shorter ICU (1.9 vs 3.4 days, P = 0.029) and hospital LOS (6 vs 7 days, P = 0.025). No differences were found between groups with respect to additional secondary end points. Simple logistic regression confirmed that deescalation was not associated with hospital mortality (odds ratio = 0.17, 95% CI, 0.02-1.70).

IMPLICATIONS

In this study of ICU patients with severe CAP and a negative BioFire PCR result, deescalation from combination β-lactam and macrolide therapy to β-lactam monotherapy was not associated with increased in-hospital mortality but was associated with decreased hospital and ICU LOS. Larger prospective studies are warranted to verify these findings.

Meta-analysis of Calibration, Discrimination, and Stratum-Specific Likelihood Ratios for the CRB-65 Score

BACKGROUND

The CRB-65 score is recommended as a decision support tool to help identify patients with community-acquired pneumonia (CAP) who can safely be treated as outpatients.

OBJECTIVE

To perform an updated meta-analysis of the accuracy, discrimination, and calibration of the CRB-65 score using a novel approach to calculation of stratum-specific likelihood ratios.

DESIGN

Meta-analysis of accuracy, discrimination, and calibration.

METHODS

We searched PubMed, Google, previous systematic reviews, and reference lists of included studies. Data was abstracted and quality assessed in parallel by two investigators. The quality assessment used an adaptation of the TRIPOD and PROBAST criteria. Measures of discrimination, calibration, and stratum-specific likelihood ratios are reported.

KEY RESULTS

Twenty-nine studies met our inclusion criteria and provided usable data. Most studies were set in Europe, none in North America, and 12 were judged to be at low risk of bias. The pooled estimate of area under the receiver operating characteristic curve was 0.74 (95% CI 0.71-0.77) for all studies. Calibration was good although there was significant heterogeneity; the pooled estimate of the ratio of observed to expected mortality for all studies was 1.04 (95% CI 0.91-1.19). The corresponding values for studies at low risk of bias where patients could be treated as outpatients or inpatients were 0.76 (0.70-0.81) and 0.88 (0.69-1.13). Summary estimates of stratum-specific likelihood ratios for all studies were 0.19 for the low-risk group, 1.1 for the moderate-risk group, and 4.5 for the high-risk group, and 0.13, 1.3, and 5.6 for studies at low risk of bias where patients could be treated as outpatients or inpatients.

CONCLUSIONS

The CRB-65 is useful for identifying low-risk patients for outpatient therapy. Given a 4% overall mortality risk, patients classified as low risk by the CRB-65 had an outpatient mortality risk of no more than 0.5%.

Guidelines to Manage Community-Acquired Pneumonia

Few guidelines have greater acceptance than that for management of community-acquired pneumonia (CAP). Despite this, areas remain controversial, and new challenges continue to emerge. Current guidelines differ from those of northern European countries predominantly in need for macrolide combination with β-lactams for hospitalized, non-intensive care unit patients. A preponderance of evidence favors combination therapy. Challenges for current and future CAP guidelines include new antibiotic classes, emergence of viruses as major causes for CAP, new diagnostic modalities, alternative risk stratification for pathogens resistant to usual CAP antibiotics, and evidence-based management of severe CAP, including immunomodulatory therapy such as corticosteroids.

Antibody Treatment against Angiopoietin-Like 4 Reduces Pulmonary Edema and Injury in Secondary Pneumococcal Pneumonia

Secondary bacterial lung infection by Streptococcus pneumoniae (S. pneumoniae) poses a serious health concern, especially in developing countries. We posit that the emergence of multiantibiotic-resistant strains will jeopardize current treatments in these regions. Deaths arising from secondary infections are more often associated with acute lung injury, a common consequence of hypercytokinemia, than with the infection per se Given that secondary bacterial pneumonia often has a poor prognosis, newer approaches to improve treatment outcomes are urgently needed to reduce the high levels of morbidity and mortality. Using a sequential dual-infection mouse model of secondary bacterial lung infection, we show that host-directed therapy via immunoneutralization of the angiopoietin-like 4 c-isoform (cANGPTL4) reduced pulmonary edema and damage in infected mice. RNA sequencing analysis revealed that anti-cANGPTL4 treatment improved immune and coagulation functions and reduced internal bleeding and edema. Importantly, anti-cANGPTL4 antibody, when used concurrently with either conventional antibiotics or antipneumolysin antibody, prolonged the median survival of mice compared to monotherapy. Anti-cANGPTL4 treatment enhanced immune cell phagocytosis of bacteria while restricting excessive inflammation. This modification of immune responses improved the disease outcomes of secondary pneumococcal pneumonia. Taken together, our study emphasizes that host-directed therapeutic strategies are viable adjuncts to standard antimicrobial treatments.IMPORTANCE Despite extensive global efforts, secondary bacterial pneumonia still represents a major cause of death in developing countries and is an important cause of long-term functional disability arising from lung tissue damage. Newer approaches to improving treatment outcomes are needed to reduce the significant morbidity and mortality caused by infectious diseases. Our study, using an experimental mouse model of secondary S. pneumoniae infection, shows that a multimodal treatment that concurrently targets host and pathogen factors improved lung tissue integrity and extended the median survival time of infected mice. The immunoneutralization of host protein cANGPTL4 reduced the severity of pulmonary edema and damage. We show that host-directed therapeutic strategies as well as neutralizing antibodies against pathogen virulence factors are viable adjuncts to standard antimicrobial treatments such as antibiotics. In view of their different modes of action compared to antibiotics, concurrent immunotherapies using antibodies are potentially efficacious against secondary pneumococcal pneumonia caused by antibiotic-resistant pathogens.

The dilemma of monotherapy or combination therapy in community-acquired pneumonia

SCOPE

To study the factors associated with mortality in hospitalized patients with community-acquired pneumonia treated with monotherapy or combination therapy.

METHODS

PubMed and Scopus were searched. Patients receiving macrolides, β-lactams and fluoroquinolones, as monotherapy or in combination, were included. Meta-analyses and meta-regressions were performed.

RESULTS

Fifty studies were included. Overall, monotherapy was not associated with higher mortality than combination (RR 1.14, 95% CI 0.99-1.32, I² 84%). Monotherapy was associated with higher mortality than combination in North American and retrospective studies. β-lactam monotherapy was associated with higher mortality than β-lactam/macrolide combination in the primary (1.32, 1.12-1.56, I² 85%) and most sensitivity analyses. There was no difference in mortality between fluoroquinolone monotherapy and β-lactam/macrolide combination (0.98, 0.78-1.23, I² 73%). In meta-regressions, the moderators that could partially explain the observed statistical heterogeneity were the frequency of cancer patients (P = .03) and Pneumonia Severity Index score IV (P = .008).

CONCLUSION

Due to the considerable heterogeneity and inclusion of unadjusted data, it is difficult to recommend a specific antibiotic regimen over another. Specific antibiotic regimens, study design and the characteristics of the population under study seem to influence the reported outcomes.

Investigational drugs in phase I and phase II clinical trials for the treatment of community-acquired pneumonia

INTRODUCTION

Community acquired pneumonia is one of the main infections, remaining as a global cause of considerable morbidity and mortality. Successful treatment hinges on expedient delivery of appropriate antibiotic therapy tailored to both the likely pathogens and the severity of disease. Although antibiotic resistance is increasing and pharmaceutical companies continue to debate the profitability of introducing new antibacterial agents, an encouraging number of new molecules have recently been unveiled which target multidrug-resistant bacteria. Areas covered: Herein, the authors summarize the actual situation of novel antibiotics for CAP in phase I & II of development. For each set of compounds, the medical significance and possible clinical placement are discussed. Current treatment options from the most important international guidelines are also reviewed. Expert opinion: Our review shows that the new antibiotics in the pipeline belong to existing antibiotic classes as β-lactams, macrolides, quinolones, oxazolidinones, tetracyclines, lipoglycopeptides, and cyclic lipopeptides and a few with a narrow spectrum of activity are novel compounds directed against novel targets. With rising outpatient antibiotic resistance in pneumonia, some of the compounds discussed are being considered for more rapid advancement in the pipeline, helping to increase the number of agents in later stages of development.

[CAPNETZ. The competence network for community-acquired pneumonia (CAP)]

CAPNETZ is a medical competence network for community-acquired pneumonia (CAP), which was funded by the German Ministry for Education and Research. It has accomplished seminal work on pneumonia over the last 15 years. A unique infrastructure was established which has so far allowed us to recruit and analyze more than 11,000 patients. The CAPNETZ cohort is the largest cohort worldwide and the results obtained relate to all relevant aspects of CAP management (epidemiology, risk stratification via biomarkers or clinical scores, pathogen spectrum, pathogen resistance, antibiotic management, prevention and health care research). Results were published in more than 150 journals and informed the preparation and update of the national S3-guideline. CAPNETZ was also the foundation for further networks like the Pneumonia Research Network on Genetic Resistance and Susceptibility for the Evolution of Severe Sepsis) (PROGRESS), the Systems Medicine of Community Acquired Pneumonia Network (CAPSyS) and SFB-TR84 (Sonderforschungsbereich - Transregio 84). The main recipients (Charité Berlin, University Clinic Ulm and the Hannover Medical School) founded the CAPNETZ foundation and transferred all data and materials rights to this foundation. Moreover, the ministry granted the CAPNETZ foundation the status of being eligible to apply for research proposals and receive research funds. Since 2013 the CAPNETZ foundation has been an associated member of the German Center for Lung Research (DZL). Thus, a solid foundation has been set up for CAPNETZ to continue its success story.

Beta-lactam plus macrolides or beta-lactam alone for community-acquired pneumonia: A systematic review and meta-analysis

It is unclear whether in the treatment of community-acquired pneumonia (CAP) beta-lactam plus macrolide antibiotics lead to better survival than beta-lactam alone. We report a systematic review and meta-analysis. Trials and observational studies published in English were included, if they provided sufficient data on odds ratio for all-cause mortality for a beta-lactam plus macrolide regimen compared with beta-lactam alone. Two investigators independently searched for eligible articles. Of 514 articles screened, 14 were included: two open-label randomized controlled trials (RCTs) comprising 1975 patients, one non-RCT interventional study comprising 1011 patients and 11 observational studies comprising 33 332 patients. Random-model meta-analysis yielded an odds ratio for all-cause death for beta-lactam plus macrolide compared with beta-lactam alone of 0.80 (95% CI 0.69-0.92, P = 0.002) with substantial heterogeneity (I(2)  = 59%, P for heterogeneity = 0.002). Severity-based subgroup analysis and meta-regression revealed that adding macrolide had a favourable effect on mortality only for severe CAP. Of the two RCTs, one suggested that macrolide plus beta-lactam lead to better outcome compared with beta-lactam alone, while the other did not. Subgrouping based on study design, that is, RCT versus non-RCT, which was almost identical to subgrouping based on severity, revealed substantial inter-subgroup heterogeneity. Compared with beta-lactam alone, beta-lactam plus macrolide may decrease all-cause death only for severe CAP. However, this conclusion is tentative because this was based mainly on observational studies.

Pneumococcal Pneumolysin Induces DNA Damage and Cell Cycle Arrest

Streptococcus pneumoniae produces pneumolysin toxin as a key virulence factor against host cells. Pneumolysin is a cholesterol-dependent cytolysin (CDC) toxin that forms lytic pores in host membranes and mediates pneumococcal disease pathogenesis by modulating inflammatory responses. Here, we show that pneumolysin, which is released during bacterial lysis, induces DNA double strand breaks (DSBs), as indicated by ataxia telangiectasia mutated (ATM)-mediated H2AX phosphorylation (γH2AX). Pneumolysin-induced γH2AX foci recruit mediator of DNA damage checkpoint 1 (MDC1) and p53 binding protein 1 (53BP1), to sites of DSBs. Importantly, results show that toxin-induced DNA damage precedes cell cycle arrest and causes apoptosis when DNA-dependent protein kinase (DNA-PK)-mediated non-homologous end joining is inhibited. Further, we observe that cells that were undergoing DNA replication harbored DSBs in greater frequency during pneumolysin treatment. This observation raises the possibility that DSBs might be arising as a result of replication fork breakdown. Additionally, neutralizing the oligomerization domain of pneumolysin with monoclonal antibody suppresses DNA damage and also cell cycle arrest, indicating that pneumolysin oligomerization is important for causing DNA damage. Taken together, this study reveals a previously unidentified ability of pneumolysin to induce cytotoxicity via DNA damage, with implications in the pathophysiology of S. pneumoniae infection.

Update on the combination effect of macrolide antibiotics in community-acquired pneumonia

Community-acquired pneumonia (CAP) is a leading cause of death from an infectious cause worldwide. Guideline-concordant antibiotic therapy initiated in a timely manner is associated with improved treatment responses and patient outcomes. In the post-antibiotic era, much of the morbidity and mortality of CAP is as a result of the interaction between bacterial virulence factors and host immune responses. In patients with severe CAP, or who are critically ill, there is a lot of emerging observational evidence demonstrating improved survival rates when treatment using combination therapy with a β-lactam and a macrolide is initiated, as compared to other antibiotic regimes without a macrolide. Macrolides in combination with a β-lactam antibiotic provide broader coverage for the atypical organisms implicated in CAP, and may contribute to antibacterial synergism. However, it has been postulated that the documented immunomodulatory effects of macrolides are the primary mechanism for improved patient outcomes through attenuation of bacterial virulence factors and host systemic inflammatory responses. Despite concerns regarding the limitations of observational evidence and the lack of confirmatory randomized controlled trials, the potential magnitude of mortality benefits estimated at 20-50% cannot be overlooked. In light of recent data from a number of trials showing that combination treatment with a macrolide and a suitable second agent is justified in all patients with severe CAP, such treatment should be obligatory for those admitted to an intensive care setting.

Antibiotic treatment strategies for community-acquired pneumonia in adults

BACKGROUND

The choice of empirical antibiotic treatment for patients with clinically suspected community-acquired pneumonia (CAP) who are admitted to non-intensive care unit (ICU) hospital wards is complicated by the limited availability of evidence. We compared strategies of empirical treatment (allowing deviations for medical reasons) with beta-lactam monotherapy, beta-lactam-macrolide combination therapy, or fluoroquinolone monotherapy.

METHODS

In a cluster-randomized, crossover trial with strategies rotated in 4-month periods, we tested the noninferiority of the beta-lactam strategy to the beta-lactam-macrolide and fluoroquinolone strategies with respect to 90-day mortality, in an intention-to-treat analysis, using a noninferiority margin of 3 percentage points and a two-sided 90% confidence interval.

RESULTS

A total of 656 patients were included during the beta-lactam strategy periods, 739 during the beta-lactam-macrolide strategy periods, and 888 during the fluoroquinolone strategy periods, with rates of adherence to the strategy of 93.0%, 88.0%, and 92.7%, respectively. The median age of the patients was 70 years. The crude 90-day mortality was 9.0% (59 patients), 11.1% (82 patients), and 8.8% (78 patients), respectively, during these strategy periods. In the intention-to-treat analysis, the risk of death was higher by 1.9 percentage points (90% confidence interval [CI], -0.6 to 4.4) with the beta-lactam-macrolide strategy than with the beta-lactam strategy and lower by 0.6 percentage points (90% CI, -2.8 to 1.9) with the fluoroquinolone strategy than with the beta-lactam strategy. These results indicated noninferiority of the beta-lactam strategy. The median length of hospital stay was 6 days for all strategies, and the median time to starting oral treatment was 3 days (interquartile range, 0 to 4) with the fluoroquinolone strategy and 4 days (interquartile range, 3 to 5) with the other strategies.

CONCLUSIONS

Among patients with clinically suspected CAP admitted to non-ICU wards, a strategy of preferred empirical treatment with beta-lactam monotherapy was noninferior to strategies with a beta-lactam-macrolide combination or fluoroquinolone monotherapy with regard to 90-day mortality. (Funded by the Netherlands Organization for Health Research and Development; CAP-START ClinicalTrials.gov number, NCT01660204.).

[Tarragona strategy--appropriate antibiotic therapy in the ICU]

BACKGROUND

Appropriate antibiotic initial therapy remarkably decreases the mortality of patients with infections in the ICU. The establishment of an appropriate initial therapy follows empirical aspects. This practice was first done for the treatment of nosocomial pneumonia. Since that time the practice became known as Tarragona strategy.

RESULTS

The basic elements of the strategy are based on the initial antibiotic treatment of patients with infections in the ICU in general and include the following: view the patient and his/her medical history, consider the microbiologic environment, in which the patient became ill, test for possible causative microorganisms and initiate high-dose antibiotics immediately, evaluate pharmacokinetic/pharmacodynamic aspects influenced by the pathophysiologic processes in the critically ill patient, the specifics of the microorganisms, the peculiarity of the antibiotics in the patient and due to therapeutic procedures, and tailor the initial broad spectrum therapy as necessary according to the microbiological results.

CONCLUSION

This procedure is safe, reduces mortality, limits the development of resistance, and is economic.

Azithromycin: mechanisms of action and their relevance for clinical applications

Azithromycin is a macrolide antibiotic which inhibits bacterial protein synthesis, quorum-sensing and reduces the formation of biofilm. Accumulating effectively in cells, particularly phagocytes, it is delivered in high concentrations to sites of infection, as reflected in rapid plasma clearance and extensive tissue distribution. Azithromycin is indicated for respiratory, urogenital, dermal and other bacterial infections, and exerts immunomodulatory effects in chronic inflammatory disorders, including diffuse panbronchiolitis, post-transplant bronchiolitis and rosacea. Modulation of host responses facilitates its long-term therapeutic benefit in cystic fibrosis, non-cystic fibrosis bronchiectasis, exacerbations of chronic obstructive pulmonary disease (COPD) and non-eosinophilic asthma. Initial, stimulatory effects of azithromycin on immune and epithelial cells, involving interactions with phospholipids and Erk1/2, are followed by later modulation of transcription factors AP-1, NFκB, inflammatory cytokine and mucin release. Delayed inhibitory effects on cell function and high lysosomal accumulation accompany disruption of protein and intracellular lipid transport, regulation of surface receptor expression, of macrophage phenotype and autophagy. These later changes underlie many immunomodulatory effects of azithromycin, contributing to resolution of acute infections and reduction of exacerbations in chronic airway diseases. A sub-group of post-transplant bronchiolitis patients appears to be sensitive to azithromycin, as may be patients with severe sepsis. Other promising indications include chronic prostatitis and periodontitis, but weak activity in malaria is unlikely to prove crucial. Long-term administration of azithromycin must be balanced against the potential for increased bacterial resistance. Azithromycin has a very good record of safety, but recent reports indicate rare cases of cardiac torsades des pointes in patients at risk.

Nemonoxacin (TG-873870) for treatment of community-acquired pneumonia

With a broad-spectrum of activity, fluoroquinolones have been widely and successfully used for decades for the treatment of and prophylaxis against various bacterial infections, including community-acquired pneumonia (CAP). However, the use of fluoroquinolones has been compromised by the emergence and spreading of bacterial resistance and the potential for adverse effects. Therefore, there is an unmet need for newer compounds that have a broader spectrum of activity to overcome existing bacterial resistance as well as the potential to minimize the risk of adverse effects. Nemonoxacin (TG-873870), a newly developed quinolone, has demonstrated broad-spectrum activity against Gram-positive, Gram-negative and atypical pathogens, including drug-resistant Streptococcus pneumoniae and methicillin-resistant Staphylococcus aureus. Results from Phases I and II studies of treatment of CAP are encouraging. This article reviews the updated data on nemonoxacin, including the bacterial susceptibility, the pharmacologic characteristics, and toxicities, and clinical trials using nemonoxacin for treatment of CAP.

Combination therapy with ampicillin and azithromycin in an experimental pneumococcal pneumonia is bactericidal and effective in down regulating inflammation in mice

Objectives

Emergence of multidrug resistance among Streptococcus pneumoniae (SP), has limited the available options used to treat infections caused by this organism. The objective of this study was to compare the role of monotherapy and combination therapy with ampicillin (AMP) and azithromycin (AZM) in eradicating bacterial burden and down regulating lung inflammation in a murine experimental pneumococcal infection model.

Methods

Balb/C mice were infected with 10⁶ CFU of SP. Treatments with intravenous ampicillin (200 mg/kg) and azithromycin (50 mg/kg) either alone or in combination was initiated 18 h post infection, animals were sacrificed from 0 – 6 h after initiation of treatment. AMP and AZM were quantified in serum by microbiological assay. Levels of TNF-α, IFN-γ IL-6, and IL-10 in serum and in lungs, along with myeloperoxidase, inflammatory cell count in broncho alveolar lavage fluid, COX-2 and histopathological changes in lungs were estimated.

Results

Combination therapy down regulated lung inflammation and accelerated bacterial clearance. This approach also significantly decreased TNF-α, IFN-γ, IL-6 and increased IL-10 level in serum and lungs along with decreased myeloperoxidase, pulmonary vascular permeability, inflammatory cell numbers and COX-2 levels in lungs.

Conclusions

Combinatorial therapy resulted in comparable bactericidal activity against the multi-drug resistant isolate and may represent an alternative dosing strategy, which may help to alleviate problems with pneumococcal pneumonia.

β-Lactam/macrolide dual therapy versus β-lactam monotherapy for the treatment of community-acquired pneumonia in adults: a systematic review and meta-analysis

OBJECTIVES

Several studies have compared the clinical effect of β-lactam/macrolide (BLM) dual therapy versus β-lactam (BL) monotherapy in community-acquired pneumonia (CAP) patients. However, the results remain controversial. Thus, we did this meta-analysis to determine which treatment was more effective.

METHODS

Databases comprising PubMed, Embase and the Cochrane Register of Controlled Trials were searched to find relevant studies. The primary outcome was mortality. The Newcastle-Ottawa scale was used to evaluate the methodological quality of included studies. Multivariable-adjusted ORs with 95% CIs were pooled in the random effects model.

RESULTS

Four prospective cohort studies and 12 retrospective cohort studies were included (n = 42 942). Compared with BL monotherapy, BLM dual therapy was significantly associated with reduced mortality (adjusted OR 0.67, 95% CI 0.61-0.73, P < 0.001, I(2) = 3%). Subsequent subgroup analyses confirmed that BLM dual therapy was statistically superior to BL monotherapy in reduction of mortality. Sensitivity analyses strengthened the validity of the results.

CONCLUSIONS

In comparison with BL monotherapy, BLM dual therapy might reduce mortality risk in patients with CAP. Because this finding is based on observational studies, randomized controlled trials are required to demonstrate the usefulness of BLM dual therapy in the treatment of CAP.

Risk factors for drug-resistant pathogens in community-acquired and healthcare-associated pneumonia

RATIONALE

Identification of patients with drug-resistant pathogens at initial diagnosis is essential for treatment of pneumonia.

OBJECTIVES

To elucidate clinical features of community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP), and to clarify risk factors for drug-resistant pathogens in patients with CAP and HCAP.

METHODS

A prospective observational study was conducted in hospitalized patients with pneumonia at 10 institutions in Japan. Pathogens identified as not susceptible to ceftriaxone, ampicillin-sulbactam, macrolides, and respiratory fluoroquinolones were defined as CAP drug-resistant pathogens (CAP-DRPs).

MEASUREMENTS AND MAIN RESULTS

In total, 1,413 patients (887 CAP and 526 HCAP) were analyzed. CAP-DRPs were more frequently found in patients with HCAP (26.6%) than in patients with CAP (8.6%). Independent risk factors for CAP-DRPs were almost identical in patients with CAP and HCAP. These included prior hospitalization (adjusted odds ratio [AOR], 2.06; 95% confidence interval [CI], 1.23-3.43), immunosuppression (AOR, 2.31; 95% CI, 1.05-5.11), previous antibiotic use (AOR, 2.45; 95% CI, 1.51-3.98), use of gastric acid-suppressive agents (AOR, 2.22; 95% CI, 1.39-3.57), tube feeding (AOR, 2.43; 95% CI, 1.18-5.00), and nonambulatory status (AOR, 2.45; 95% CI, 1.40-4.30) in the combined patients with CAP and HCAP. The area under the receiver operating characteristic curve for counting the number of risk factors was 0.79 (95% CI, 0.74-0.84).

CONCLUSIONS

The clinical profile of HCAP was different from that of CAP. However, physicians can predict drug resistance in patients with either CAP or HCAP by taking account of the cumulative number of the risk factors. Clinical trial registered with https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000004001&language=E ; number UMIN000003306.

Community-acquired pneumonia at the Hospital de Clínicas de Porto Alegre: evaluation of a care protocol

To assess the adequacy of medical prescriptions for community-acquired pneumonia at the emergency department of the Hospital de Clínicas de Porto Alegre, we conducted a prospective cohort study, from January through April 2011. All patients with suspected pneumonia were selected from the first prescription of antimicrobials held in the emergency room. Patients with a description of pneumonia, community-acquired pneumonia, respiratory infection, or other issues related to community-acquired pneumonia were selected for review. Two-hundred and fifteen patients were studied. Adherence to the hospital care protocol was: 11.2% for the initial recommended tests (chest X-ray and collection of sputum sample), 34.4% for blood cultures, and 92.1% for the antimicrobial choice. Sixty percent of the prescriptions consisted of a combination of drugs, and the association of beta-lactam and macrolide was the most common. The Hospital Infection Control Committee evaluated patients' prescriptions within a median time of 23.5h (IQR 25-75%, 8-24). Negative evaluations accounted for 10% of prescriptions (n=59). Fourteen percent of the patients died during hospitalization. In the multivariate analysis, Pneumonia Severity Index Score and use of ampicillin+sulbactam alone were independently related to in-hospital mortality. There was a high adherence to the hospital's CAP protocol, in relation to antimicrobial choice. Severity score and use of ampicillin+sulbactam alone were independently associated to in-hospital death.

Azithromycin and survival in Streptococcus pneumoniae pneumonia: a retrospective study

OBJECTIVE

Streptococcus pneumoniae (SP) represents a major pathogen in pneumonia. The impact of azithromycin on mortality in SP pneumonia remains unclear. Recent safety concerns regarding azithromycin have raised alarm about this agent's role with pneumonia. We sought to clarify the relationship between survival and azithromycin use in SP pneumonia.

DESIGN

Retrospective cohort.

SETTING

Urban academic hospital.

PARTICIPANTS

Adults with a diagnosis of SP pneumonia (January-December 2010). The diagnosis of pneumonia required a compatible clinical syndrome and radiographic evidence of an infiltrate.

INTERVENTION

None.

PRIMARY AND SECONDARY OUTCOME MEASURES

Hospital mortality served as the primary endpoint, and we compared patients given azithromycin with those not treated with this. Covariates of interest included demographics, severity of illness, comorbidities and infection-related characteristics (eg, appropriateness of initial treatment, bacteraemia). We employed logistic regression to assess the independent impact of azithromycin on hospital mortality.

RESULTS

The cohort included 187 patients (mean age: 67.0±8.2 years, 50.3% men, 5.9% admitted to the intensive care unit). The most frequently utilised non-macrolide antibiotics included: ceftriaxone (n=111), cefepime (n=31) and moxifloxacin (n=22). Approximately two-thirds of the cohort received azithromycin. Crude mortality was lower in persons given azithromycin (5.6% vs 23.6%, p<0.01). The final survival model included four variables: age, need for mechanical ventilation, initial appropriate therapy and azithromycin use. The adjusted OR for mortality associated with azithromycin equalled 0.26 (95% CI 0.08 to 0.80, p=0.018).

CONCLUSIONS

SP pneumonia generally remains associated with substantial mortality while azithromycin treatment is associated with significantly higher survival rates. The impact of azithromycin is independent of multiple potential confounders.

Macrolide-based regimens in absence of bacterial co-infection in critically ill H1N1 patients with primary viral pneumonia

PURPOSE

To determine whether macrolide-based treatment is associated with mortality in critically ill H1N1 patients with primary viral pneumonia.

METHODS

Secondary analysis of a prospective, observational, multicenter study conducted across 148 Intensive Care Units (ICU) in Spain.

RESULTS

Primary viral pneumonia was present in 733 ICU patients with pandemic influenza A (H1N1) virus infection with severe respiratory failure. Macrolide-based treatment was administered to 190 (25.9 %) patients. Patients who received macrolides had chronic obstructive pulmonary disease more often, lower severity on admission (APACHE II score on ICU admission (13.1 ± 6.8 vs. 14.4 ± 7.4 points, p < 0.05), and multiple organ dysfunction syndrome less often (23.4 vs. 30.1 %, p < 0.05). Length of ICU stay in survivors was not significantly different in patients who received macrolides compared to patients who did not (10 (IQR 4-20) vs. 10 (IQR 5-20), p = 0.9). ICU mortality was 24.1 % (n = 177). Patients with macrolide-based treatment had lower ICU mortality in the univariate analysis (19.2 vs. 28.1 %, p = 0.02); however, a propensity score analysis showed no effect of macrolide-based treatment on ICU mortality (OR = 0.87; 95 % CI 0.55-1.37, p = 0.5). Moreover, the sensitivity analysis revealed very similar results (OR = 0.91; 95 % CI 0.58-1.44, p = 0.7). A separate analysis of patients under mechanical ventilation yielded similar results (OR = 0.77; 95 % CI 0.44-1.35, p = 0.4).

CONCLUSION

Our results suggest that macrolide-based treatment was not associated with improved survival in critically ill H1N1 patients with primary viral pneumonia.

Community-acquired pneumonia

Community-acquired pneumonia (CAP) is one of the most common acute infections requiring admission to hospital. The main causative pathogens of CAP are Streptococcus pneumoniae, influenza A, Mycoplasma pneumoniae and Chlamydophila pneumoniae, and the dominant risk factors are age, smoking and comorbidities. The incidence of CAP and its common complications, such as the requirement for intensive care and complicated parapneumonic effusions, are increasing, making it essential for all physicians to have a good understanding of the management of CAP. Although the diagnosis and treatment of CAP is straightforward in most cases, it can be more complex, and recent data indicate that the mortality of CAP in the UK is surprisingly high. In the future, routine use of biomarkers to improve risk stratification and tailor management to individual patients could improve outcomes, and there is some evidence that modulation of CAP-associated inflammation could also be beneficial. Both research into host-microbial interactions in the lung and clinical trials of different management and preventative treatments are urgently needed to combat the increasing morbidity and mortality associated with CAP.

Antibiotic prescription patterns in the empiric therapy of severe sepsis: combination of antimicrobials with different mechanisms of action reduces mortality

Introduction

Although early institution of adequate antimicrobial therapy is lifesaving in sepsis patients, optimal antimicrobial strategy has not been established. Moreover, the benefit of combination therapy over monotherapy remains to be determined. Our aims are to describe patterns of empiric antimicrobial therapy in severe sepsis, assessing the impact of combination therapy, including antimicrobials with different mechanisms of action, on mortality.

Methods

This is a Spanish national multicenter study, analyzing all patients admitted to ICUs who received antibiotics within the first 6 hours of diagnosis of severe sepsis or septic shock. Antibiotic-prescription patterns in community-acquired infections and nosocomial infections were analyzed separately and compared. We compared the impact on mortality of empiric antibiotic treatment, including antibiotics with different mechanisms of action, termed different-class combination therapy (DCCT), with that of monotherapy and any other combination therapy possibilities (non-DCCT).

Results

We included 1,372 patients, 1,022 (74.5%) of whom had community-acquired sepsis and 350 (25.5%) of whom had nosocomial sepsis. The most frequently prescribed antibiotic agents were β-lactams (902, 65.7%) and carbapenems (345, 25.1%). DCCT was administered to 388 patients (28.3%), whereas non-DCCT was administered to 984 (71.7%). The mortality rate was significantly lower in patients administered DCCTs than in those who were administered non-DCCTs (34% versus 40%; P = 0.042). The variables independently associated with mortality were age, male sex, APACHE II score, and community origin of the infection. DCCT was a protective factor against in-hospital mortality (odds ratio (OR), 0.699; 95% confidence interval (CI), 0.522 to 0.936; P = 0.016), as was urologic focus of infection (OR, 0.241; 95% CI, 0.102 to 0.569; P = 0.001).

Conclusions

β-Lactams, including carbapenems, are the most frequently prescribed antibiotics in empiric therapy in patients with severe sepsis and septic shock. Administering a combination of antimicrobials with different mechanisms of action is associated with decreased mortality.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Swedish guidelines on the management of community-acquired pneumonia in immunocompetent adults--Swedish Society of Infectious Diseases 2012

This document presents the 2012 evidence based guidelines of the Swedish Society of Infectious Diseases for the in- hospital management of adult immunocompetent patients with community-acquired pneumonia (CAP). The prognostic score 'CRB-65' is recommended for the initial assessment of all CAP patients, and should be regarded as an aid for decision-making concerning the level of care required, microbiological investigation, and antibiotic treatment. Due to the favourable antibiotic resistance situation in Sweden, an initial narrow-spectrum antibiotic treatment primarily directed at Streptococcus pneumoniae is recommended in most situations. The recommended treatment for patients with severe CAP (CRB-65 score 2) is penicillin G in most situations. In critically ill patients (CRB-65 score 3-4), combination therapy with cefotaxime/macrolide or penicillin G/fluoroquinolone is recommended. A thorough microbiological investigation should be undertaken in all patients, including blood cultures, respiratory tract sampling, and urine antigens, with the addition of extensive sampling for more uncommon respiratory pathogens in the case of severe disease. Recommended measures for the prevention of CAP include vaccination for influenza and pneumococci, as well as smoking cessation.

Pathogen- and host-directed anti-inflammatory activities of macrolide antibiotics

Macrolide antibiotics possess several, beneficial, secondary properties which complement their primary antimicrobial activity. In addition to high levels of tissue penetration, which may counteract seemingly macrolide-resistant bacterial pathogens, these agents also possess anti-inflammatory properties, unrelated to their primary antimicrobial activity. Macrolides target cells of both the innate and adaptive immune systems, as well as structural cells, and are beneficial in controlling harmful inflammatory responses during acute and chronic bacterial infection. These secondary anti-inflammatory activities of macrolides appear to be particularly effective in attenuating neutrophil-mediated inflammation. This, in turn, may contribute to the usefulness of these agents in the treatment of acute and chronic inflammatory disorders of both microbial and nonmicrobial origin, predominantly of the airways. This paper is focused on the various mechanisms of macrolide-mediated anti-inflammatory activity which target both microbial pathogens and the cells of the innate and adaptive immune systems, with emphasis on their clinical relevance.

Guidelines for the management of adult lower respiratory tract infections--summary

This document is an update of Guidelines published in 2005 and now includes scientific publications through to May 2010. It provides evidence-based recommendations for the most common management questions occurring in routine clinical practice in the management of adult patients with LRTI. Topics include management outside hospital, management inside hospital (including community-acquired pneumonia (CAP), acute exacerbations of COPD (AECOPD), acute exacerbations of bronchiectasis) and prevention. The target audience for the Guideline is thus all those whose routine practice includes the management of adult LRTI.

Guideline adherence and macrolides reduced mortality in outpatients with pneumonia

BACKGROUND

For outpatients with pneumonia, guidelines recommend empiric antibiotics and some suggest macrolides are preferred agents. We hypothesized that both guideline-concordant antibiotics and macrolides would be associated with reduced mortality.

METHODS

All outpatients with pneumonia assessed at 7 Emergency Departments in Edmonton, Alberta, Canada were enrolled in a population-based registry that included clinical-radiographic data, Pneumonia Severity Index (PSI) and treatments. Guideline-concordant regimens included macrolides and respiratory fluoroquinolones; other regimens were "discordant". Main outcome was 30-day all-cause mortality.

RESULTS

The study included 2973 outpatients; mean age 51 years, 47% female, most had mild pneumonia (73% PSI Class I-II). Over 30-days, 38 (1%) patients died, 228 (8%) were hospitalized, and 253 (9%) reached the endpoint of death or hospitalization. Most (2845 [96%]) patients received guideline-concordant antibiotics. Compared to patients receiving discordant antibiotics, those receiving guideline-concordant antibiotics were less likely to die within 30-days (8 [6%] versus 30 [1%], adjusted OR 0.23, 95% CI 0.09-0.59, p = 0.002). Within the guideline-concordant subgroup, compared to the 947 (33%) patients treated with fluoroquinolones, those receiving macrolides [1847 (64%)] were less likely to die (25 [3%] versus 4 [0.2%], adjusted OR 0.28, 95% CI 0.09-0.86, p = 0.03).

CONCLUSIONS

In outpatients with pneumonia, treatment with guideline-concordant antibiotics and macrolides were both associated with mortality reduction.

Combination antibiotic therapy for community-acquired pneumonia

Community-acquired pneumonia (CAP) is a common and potentially serious illness that is associated with morbidity and mortality. Although medical care has improved during the past decades, it is still potentially lethal. Streptococcus pneumoniae is the most frequent microorganism isolated. Treatment includes mandatory antibiotic therapy and organ support as needed. There are several antibiotic therapy regimens that include β-lactams or macrolides or fluoroquinolones alone or in combination. Combination antibiotic therapy achieves a better outcome compared with monotherapy and it should be given in the following subset of patients with CAP: outpatients with comorbidities and previous antibiotic therapy, nursing home patients with CAP, hospitalized patients with severe CAP, bacteremic pneumococcal CAP, presence of shock, and necessity of mechanical ventilation. Better outcome is associated with combination therapy that includes a macrolide for wide coverage of atypical pneumonia, polymicrobial pneumonia, or resistant Streptococcus pneumoniae. Macrolides have shown different properties other than antimicrobial activity, such as anti-inflammatory properties. Although this evidence comes from observational, most of them retrospective and nonblinded studies, the findings are consistent. Ideally, a prospective, multicenter, randomized trial should be performed to confirm these findings.

Guidelines for the management of adult lower respiratory tract infections--full version

This document is an update of Guidelines published in 2005 and now includes scientific publications through to May 2010. It provides evidence-based recommendations for the most common management questions occurring in routine clinical practice in the management of adult patients with LRTI. Topics include management outside hospital, management inside hospital (including community-acquired pneumonia (CAP), acute exacerbations of COPD (AECOPD), acute exacerbations of bronchiectasis) and prevention. Background sections and graded evidence tables are also included. The target audience for the Guideline is thus all those whose routine practice includes the management of adult LRTI.

Modern Management of Community-Acquired Pneumonia: Is It Cost-Effective and are Outcomes Acceptable?

Community-acquired pneumonia (CAP) is the most important cause of death from infectious diseases in the developed world and is associated with a high economic burden. Researchers have therefore sought ways to improve CAP outcomes while reducing costs. In this review, we highlight the current evidence supporting modern approaches to CAP management, including the use of severity indices to safely increase the proportion of patients treated at home, the use of procalcitonin to decrease antibiotic use, early intravenous to oral switch of antibiotic therapy, streamlining antimicrobials, and approaches to shorten antibiotic treatment duration. Although promising evidence exists for these modern strategies, there is still a considerable lack of high-quality evidence proving noninferiority of clinical outcomes and cost-effectiveness.

Mechanisms of action and clinical application of macrolides as immunomodulatory medications

Macrolides have diverse biological activities and an ability to modulate inflammation and immunity in eukaryotes without affecting homeostatic immunity. These properties have led to their long-term use in treating neutrophil-dominated inflammation in diffuse panbronchiolitis, bronchiectasis, rhinosinusitis, and cystic fibrosis. These immunomodulatory activities appear to be polymodal, but evidence suggests that many of these effects are due to inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and nuclear factor kappa B (NF-kappaB) activation. Macrolides accumulate within cells, suggesting that they may associate with receptors or carriers responsible for the regulation of cell cycle and immunity. A concern is that long-term use of macrolides increases the emergence of antimicrobial resistance. Nonantimicrobial macrolides are now in development as potential immunomodulatory therapies.

Advances in the prevention, management, and treatment of community-acquired pneumonia

Despite the availability of powerful antibiotics, community-acquired pneumonia (CAP) remains one of the leading reasons for morbidity and mortality worldwide, and despite the availability of powerful antibiotics, there has been only little improvement in case fatality rates for many years. Consequently, it cannot be expected that novel antibiotics will substantially improve outcomes in CAP. Therefore, this review focuses on novel approaches that may reduce CAP-related mortality: the impact of immunomodulation by macrolides and fluoroquinolones and the prevention of CAP by pneumococcal vaccines.