Comparison of beta-lactam and macrolide combination therapy versus fluoroquinolone monotherapy in hospitalized Veterans Affairs patients with community-acquired pneumonia

Antibiotic Strategies for Severe Community-Acquired Pneumonia

Despite advancements in health systems and intensive care unit (ICU) care, along with the introduction of novel antibiotics and microbiologic techniques, mortality rates in severe community-acquired pneumonia (sCAP) patients have not shown significant improvement. Delayed admission to the ICU is a major risk factor for higher mortality. Apart from choosing the appropriate site of care, prompt and appropriate antibiotic therapy significantly affects the prognosis of sCAP. Treatment regimens involving ceftaroline or ceftobiprole are currently considered the best options for managing patients with sCAP. Additionally, several other molecules, such as delafloxacin, lefamulin, and omadacycline, hold promise as therapeutic strategies for sCAP. This review aims to provide a comprehensive summary of the key challenges in managing adults with severe CAP, focusing on essential aspects related to antibiotic treatment and investigating potential strategies to enhance clinical outcomes in sCAP patients.

Convergent impact of vaccination and antibiotic pressures on pneumococcal populations

Streptococcus pneumoniae is a remarkably adaptable and successful human pathogen, playing dual roles of both asymptomatic carriage in the nasopharynx and invasive disease including pneumonia, bacteremia, and meningitis. Efficacious vaccines and effective antibiotic therapies are critical to mitigating morbidity and mortality. However, clinical interventions can be rapidly circumvented by the pneumococcus by its inherent proclivity for genetic exchange. This leads to an underappreciated interplay between vaccine and antibiotic pressures on pneumococcal populations. Circulating populations have undergone dramatic shifts due to the introduction of capsule-based vaccines of increasing valency imparting strong selective pressures. These alterations in population structure have concurrent consequences on the frequency of antibiotic resistance profiles in the population. This review will discuss the interactions of these two selective forces. Understanding and forecasting the drivers of antibiotic resistance and capsule switching are of critical importance for public health, particularly for such a genetically promiscuous pathogen as S. pneumoniae.

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.

Antibiotic prescribing by age, sex, race, and ethnicity for patients admitted to the hospital with community-acquired bacterial pneumonia (CABP) in the All of Us database

Purpose

To assess the proportion of inpatients who received guideline-concordant antibiotics for community-acquired bacterial pneumonia (CABP) in special populations of the All of Us database.

Background

CABP contributes significantly to healthcare burden worldwide. The American Thoracic Society and Infectious Disease Society of America jointly published guidelines for the treatment of CABP. Guideline-concordant antibiotics for CABP are associated with better patient and cost outcomes.

Methods

This was a retrospective cohort study of patients with pneumonia (n = 1608; SNOMED 233604007) from 10/1/2018 to 1/01/22 in the All of Us database. Cases were excluded for treatment setting other than inpatient, prior (within 90 days) pneumonia, receipt of intravenous antibiotics, respiratory isolation of methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa, and/or other non-community-acquired types of pneumonia. Patients were grouped based on patient age, sex, race, and ethnicity. The proportion of patients on guideline-concordant therapy was compared within groups using chi-square statistics. Significant associations were assessed using multivariate logistic regression models.

Results

A total of 1608 cases were included, and 45% of these patients received guideline-concordant antibiotics. Non-Hispanic White (NHW) patients vs. Black patients were associated with a 36% higher likelihood for receiving guideline-concordant antibiotics (adjusted OR, 1.36; 95% CI 1.02-1.81), whereas NHW vs. Hispanic patients were associated with a 34% lower likelihood for receiving guideline-concordant antibiotics (aOR 0.66; 0.48-0.91).

Conclusion

Black patients with CABP in the All of Us database were less likely to receive guideline-concordant antibiotics, and Hispanic patients were more likely to receive guideline-concordant antibiotics, than NHW patients.

Ceftriaxone versus ampicillin for the treatment of community-acquired pneumonia. A propensity matched cohort study

OBJECTIVES

Ceftriaxone is recommended as first-line antibiotic treatment (with the addition of macrolide) for hospitalised adults with community acquired pneumonia (CAP). Narrower-spectrum β-lactam as ampicillin, may be associated with comparable clinical outcomes, with less emergence of resistant pathogens or Clostridioides difficile infection (CDI). We aimed to examine whether ampicillin and ceftriaxone (with the addition of macrolides for both arms) are comparable for the treatment of hospitalized adults due to CAP.

METHODS

This was a single center, observational cohort study. We included adult patients who were hospitalized in internal medicine wards due to CAP and were treated with either ceftriaxone or ampicillin with the addition of macrolide. A propensity-score model was used. The primary outcome was 30-day all-cause mortality. A multivariable logistic regression analysis and Kaplan-Meier survival analysis was performed. We performed subgroup analyses for the main outcome based on CURB-65 score and age.

RESULTS

A total of 1586 patients fulfilled the inclusion criteria. There was no difference in 30-day mortality rate in the total cohort (28/233 vs. 208/1353 in ampicillin and ceftriaxone arm, respectively; p = 0.184). In the propensity matched cohort (197 in ampicillin and 394 in ceftriaxone arm), there was no significant difference in 30-day all-cause mortality between treatment groups in multivariable analysis of the main model (OR 0.67, 95% CI, 0.37-1.2; p = 0.189) and Kaplan-Meier survival analysis (p = 0.108). Thirty-day mortality rate was (19/197 vs. 57/394, in ampicillin and ceftriaxone arms, respectively; p = 0.108) Patients who were treated with ampicillin experienced significantly lower rates of CDI (0/197, 0% vs. 8/394, 2%; p = 0.044).

DISCUSSION

Ampicillin was associated with comparable clinical outcomes in comparison to ceftriaxone for patients who were hospitalized due to CAP. Ampicillin was associated with significantly lower rate of CDI. Results need to be confirmed by more robust study designs.

The Effect of Macrolides on Mortality in Bacteremic Pneumococcal Pneumonia: A Retrospective, Nationwide Cohort Study, Israel, 2009-2017

BACKGROUND

Previous cohort studies of pneumonia patients reported lower mortality with advanced macrolides. Our aim was to characterize antibiotic treatment patterns and assess the role of quinolones or macrolides in empirical therapy.

MATERIALS

An historical cohort, 1 July 2009 to 30 June 2017, included, through active surveillance, all culture-confirmed bacteremic pneumococcal pneumonia (BPP) among adults in Israel. Cases without information on antibiotic treatment were excluded. Logistic regression analysis was used to assess independent predictors of in-hospital mortality.

RESULTS

A total of 2016 patients with BPP were identified. The median age was 67.2 years (interquartile range [IQR] 53.2-80.6); 55.1% were men. Lobar pneumonia was present in 1440 (71.4%), multi-lobar in 576 (28.6%). Median length of stay was 6 days (IQR 4-11). A total of 1921 cases (95.3%) received empiric antibiotics with anti-pneumococcal coverage: ceftriaxone, in 1267 (62.8%). Coverage for atypical bacteria was given to 1159 (57.5%), 64% of these, with macrolides. A total of 372 (18.5%) required mechanical ventilation, and 397 (19.7%) died. Independent predictors of mortality were age (odds ratio [OR] 1.051, 95% confidence interval [CI] 1.039, 1.063), being at high-risk for pneumococcal disease (OR 2.040, 95% CI 1.351, 3.083), multi-lobar pneumonia (OR 2.356, 95% CI 1.741, 3.189). Female sex and macrolide therapy were predictors of survival: (OR 0.702, 95% CI .516, .955; and OR 0.554, 95% CI .394, .779, respectively). Either azithromycin or roxithromycin treatment for as short as two days was predictor of survival. Quinolone therapy had no effect.

CONCLUSIONS

Empirical therapy with macrolides reduced odds for mortality by 45%. This effect was evident with azithromycin and with roxithromycin. The effect did not require a full course of therapy.

Management of pneumonia in critically ill patients

Severe pneumonia is associated with high mortality (short and long term), as well as pulmonary and extrapulmonary complications. Appropriate diagnosis and early initiation of adequate antimicrobial treatment for severe pneumonia are crucial in improving survival among critically ill patients. Identifying the underlying causative pathogen is also critical for antimicrobial stewardship. However, establishing an etiological diagnosis is challenging in most patients, especially in those with chronic underlying disease; those who received previous antibiotic treatment; and those treated with mechanical ventilation. Furthermore, as antimicrobial therapy must be empiric, national and international guidelines recommend initial antimicrobial treatment according to the location's epidemiology; for patients admitted to the intensive care unit, specific recommendations on disease management are available. Adherence to pneumonia guidelines is associated with better outcomes in severe pneumonia. Yet, the continuing and necessary research on severe pneumonia is expansive, inviting different perspectives on host immunological responses, assessment of illness severity, microbial causes, risk factors for multidrug resistant pathogens, diagnostic tests, and therapeutic options.

Comparative efficacy of azithromycin versus clarithromycin in combination with beta-lactams to treat community-acquired pneumonia in hospitalized patients: a systematic review

OBJECTIVE

The objective was to compare the efficacy of azithromycin and clarithromycin in combination with beta-lactams to treat community-acquired pneumonia among hospitalized adults.

METHODS

Five databases (PubMed, Google Scholar, Trip, Medline, and Clinical Key) were searched to identify randomized clinical trials with patients exposed to azithromycin or clarithromycin in combination with a beta-lactam. All articles were critically reviewed for inclusion in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Seven clinical trials were included. The treatment success rate for azithromycin-beta-lactam after 10 to 14 days was 87.55% and that for clarithromycin-beta-lactam after 5 to 7 days of therapy was 75.42%. Streptococcus pneumoniae was commonly found in macrolide groups, with 130 and 80 isolates in the clarithromycin-based and azithromycin-based groups, respectively. The length of hospital stay was an average of 8.45 days for patients receiving a beta-lactam-azithromycin combination and 7.25 days with a beta-lactam-clarithromycin combination.

CONCLUSION

Macrolide inter-class differences were noted, with a higher clinical success rate for azithromycin-based combinations. However, a shorter length of hospital stay was achieved with a clarithromycin-beta-lactam regimen. Thus, a macrolide combined with a beta-lactam should be chosen using susceptibility data from the treating facility.

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.

Updates on community acquired pneumonia management in the ICU

While the world is grappling with the consequences of a global pandemic related to SARS-CoV-2 causing severe pneumonia, available evidence points to bacterial infection with Streptococcus pneumoniae as the most common cause of severe community acquired pneumonia (SCAP). Rapid diagnostics and molecular testing have improved the identification of co-existent pathogens. However, mortality in patients admitted to ICU remains staggeringly high.

The American Thoracic Society and Infectious Diseases Society of America have updated CAP guidelines to help streamline disease management. The common theme is use of timely, appropriate and adequate antibiotic coverage to decrease mortality and avoid drug resistance. Novel antibiotics have been studied for CAP and extend the choice of therapy, particularly for those who are intolerant of, or not responding to standard treatment, including those who harbor drug resistant pathogens. In this review, we focus on the risk factors, microbiology, site of care decisions and treatment of patients with SCAP.

Correlating Drug-Target Residence Time and Post-antibiotic Effect: Insight into Target Vulnerability

Target vulnerability correlates the level of drug-target engagement required to generate a pharmacological response. High vulnerability targets are those that require only a relatively small fraction of occupancy to achieve the desired pharmacological outcome, whereas low vulnerability targets require high levels of engagement. Here, we demonstrate that the slope of the correlation between drug-target residence time and the post-antibiotic effect (PAE) can be used to define the vulnerability of bacterial targets. For macrolides, a steep slope is observed between residence time on the E. coli ribosome and the PAE, indicating that the ribosome is a highly vulnerable drug target. The analysis of the residence time-PAE data for erythromycin, azithromycin, spiramycin, and telithromycin using a mechanistic pharmacokinetic-pharmacodynamic model that integrates drug-target kinetics into predictions of drug activity lead to the successful prediction of the cellular PAE for tylosin, which has the longest residence time (7.1 h) and PAE (5.8 h). Although the macrolide data support a connection between residence time, PAE, and bactericidality, many bactericidal β-lactam antibiotics do not give a PAE, illustrating the role of factors such as protein resynthesis in the expression of target vulnerability.

Survival benefit associated with clarithromycin in severe community-acquired pneumonia: A matched comparator study

Although analysis of retrospective studies has documented survival benefit from the addition of a macrolide to the treatment regimen for community-acquired pneumonia (CAP), no data are available to determine if there is differential efficacy between members of the macrolide family. In order to investigate this, an analysis was undertaken of data from 1174 patients with CAP who met the new Sepsis-3 definitions and were enrolled prospectively in the data registry of the Hellenic Sepsis Study Group. Four well-matched treatment groups were identified with 130 patients per group: clarithromycin and β-lactam; azithromycin and β-lactam; respiratory fluoroquinolone and β-lactam monotherapy. The primary endpoint was comparison of the effects of clarithromycin with β-lactam monotherapy on 28-day mortality. The secondary endpoint was resolution of CAP. Mortality rates for the clarithromycin, azithromycin, respiratory fluoroquinolone and β-lactam groups were 20.8%, 33.8% (P=0.026 vs clarithromycin), 32.3% (P=0.049 vs clarithromycin) and 36.2% (P=0.009 vs clarithromycin), respectively. After stepwise Cox regression analysis among all groups, clarithromycin was the only treatment modality associated with a favourable outcome (hazard ratio 0.61; P=0.021). CAP resolved in 73.1%, 65.9% (P=0.226 vs clarithromycin), 58.5% (P=0.009 vs clarithromycin) and 61.5% (P=0.046 vs clarithromycin) of patients, respectively. It is concluded that the addition of clarithromycin to the treatment regimen of patients with severe CAP leads to better survival rates.

Treating bacterial pneumonia in people living with HIV

Introduction: Bacterial pneumonia remains an important cause of morbidity and mortality in people living with HIV (PLWH) in the antiretroviral therapy (ART) era. In addition to being immunocompromised, as reflected by low CD4 cell counts and elevated HIV viral loads, PLWH often have other behaviors associated with an increased risk of pneumonia including smoking and injected drug use. As PLWH are aging, comorbid conditions such as chronic obstructive pulmonary disease (COPD), cancers, and cardiovascular, renal and liver diseases are emerging as additional risk factors for pneumonia. Pathogens are often similar to those in HIV-uninfected individuals; however, PLWH are at risk for unusual and/or multi-drug resistant organisms causing bacterial pneumonia based, in part, on their CD4 cell counts and other exposures. Areas covered: In this review, we focus on the recognition and management of bacterial community-acquired pneumonia (CAP) in PLWH. Along with antimicrobial treatment, we discuss prevention strategies such as vaccination and smoking cessation. Expert opinion: Early initiation of ART after HIV infection can decrease the risk of pneumonia. Improved efforts at vaccination, smoking cessation, and reduction of other substance use are urgently needed in PLWH to decrease the risk for bacterial pneumonia. As PLWH are aging, comorbidities are additional risk factors for bacterial CAP.

Guideline for Antibiotic Use in Adults with Community-acquired Pneumonia

Community-acquired pneumonia is common and important infectious disease in adults. This work represents an update to 2009 treatment guideline for community-acquired pneumonia in Korea. The present clinical practice guideline provides revised recommendations on the appropriate diagnosis, treatment, and prevention of community-acquired pneumonia in adults aged 19 years or older, taking into account the current situation regarding community-acquired pneumonia in Korea. This guideline may help reduce the difference in the level of treatment between medical institutions and medical staff, and enable efficient treatment. It may also reduce antibiotic resistance by preventing antibiotic misuse against acute lower respiratory tract infection in Korea.

Mortality in patients with community-onset pneumonia at low risk of drug-resistant pathogens: Impact of β-lactam plus macrolide combination therapy

BACKGROUND AND OBJECTIVE

Drug-resistant pathogen (DRP) risk stratification is important for choosing a treatment strategy for community-onset pneumonia. Evidence for benefits of non-antipseudomonal β-lactam plus macrolide combination therapy (BLM) on mortality is limited in patients at low DRP risk. Risk factors for mortality remain to be clarified.

METHODS

Post hoc analysis using a prospective multicentre study cohort of community-onset pneumonia was performed to assess 30-day differences in mortality between non-antipseudomonal β-lactam monotherapy (BL) and BLM groups. Logistic regression analysis was performed to assess the therapeutic effect and risk factors for mortality in patients at low DRP risk.

RESULTS

In total, 594 patients with community-onset pneumonia at low DRP risk (369 BL and 225 BLM) were analysed. The 30-day mortality in BL and BLM was 13.8% and 1.8%, respectively (P < 0.001). Multivariate analysis showed that BLM reduced the 30-day mortality (adjusted odds ratio: 0.28, 95% CI: 0.09-0.87) compared with BL. Independent prognostic factors for 30-day mortality included arterial partial pressure of carbon dioxide (PaCO₂ ) > 50 mm Hg, white blood cell count < 4000/mm³ , non-ambulatory status, albumin < 3.0 g/dL, haematocrit < 30%, age ≥ 80 years, respiratory rate > 25/min and body temperature < 36°C.

CONCLUSION

In patients with community-onset pneumonia at low DRP risk, BLM treatment reduced 30-day mortality compared with BL. Independent risk factors for mortality are potential confounding factors when assessing antibiotic effects in randomized clinical trials.

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.

Combination Susceptibility Testing of Common Antimicrobials in Vitro and the Effects of Sub-MIC of Antimicrobials on Staphylococcus aureus Biofilm Formation

The current study was conducted to evaluate the antibacterial combination efficacies, and whether the sub-inhibitory concentrations (sub-MIC) of antibiotics can influent on the biofilm formation of S. aureus. The minimum inhibitory concentration (MIC) of common antibacterial drugs was determined in vitro against clinical isolates of Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pasteurella multocida (P. multocida) alone and in combination with each other by using the broth microdilution method and the checkerboard micro-dilution method analyzed with the fractional inhibitory concentration index (FICI), respectively. Regarding these results, antibacterial drug combinations were categorized as synergistic, interacting, antagonistic and indifferent, and most of the results were consistent with the previous reports. Additionally, the effects of sub-MIC of seven antimicrobials (kanamycin, acetylisovaleryltylosin tartrate, enrofloxacin, lincomycin, colistin sulfate, berberine, and clarithromycin) on S. aureus biofilm formation were determined via crystal violet staining, scanning electron microscopy (SEM) and real-time PCR. Our results demonstrate that all antibiotics, except acetylisovaleryltylosin tartrate, effectively reduced the S. aureus biofilm formation. In addition, real-time reverse transcriptase PCR was used to analyze the relative expression levels of S. aureus biofilm-related genes such as sarA, fnbA, rbf, lrgA, cidA, and eno after the treatment at sub-MIC with all of the six antimicrobials. All antibiotics significantly inhibited the expression of these biofilm-related genes except for acetylisovaleryltylosin tartrate, which efficiently up-regulated these transcripts. These results provide the theoretical parameters for the selection of effective antimicrobial combinations in clinical therapy and demonstrate how to correctly use antibiotics at sub-MIC as preventive drugs.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pneumolysin as a potential therapeutic target in severe pneumococcal disease

Acute pulmonary and cardiac injury remain significant causes of morbidity and mortality in those afflicted with severe pneumococcal disease, with the risk for early mortality often persisting several years beyond clinical recovery. Although remaining to be firmly established in the clinical setting, a considerable body of evidence, mostly derived from murine models of experimental infection, has implicated the pneumococcal, cholesterol-binding, pore-forming toxin, pneumolysin (Ply), in the pathogenesis of lung and myocardial dysfunction. Topics covered in this review include the burden of pneumococcal disease, risk factors, virulence determinants of the pneumococcus, complications of severe disease, antibiotic and adjuvant therapies, as well as the structure of Ply and the role of the toxin in disease pathogenesis. Given the increasing recognition of the clinical potential of Ply-neutralisation strategies, the remaining sections of the review are focused on updates of the types, benefits and limitations of currently available therapies which may attenuate, directly and/or indirectly, the injurious actions of Ply. These include recently described experimental therapies such as various phytochemicals and lipids, and a second group of more conventional agents the members of which remain the subject of ongoing clinical evaluation. This latter group, which is covered more extensively, encompasses macrolides, statins, corticosteroids, and platelet-targeted therapies, particularly aspirin.

Efficacy of β-Lactam-plus-Macrolide Combination Therapy in a Mouse Model of Lethal Pneumococcal Pneumonia

Community-acquired pneumonia is a common disease with considerable morbidity and mortality, for which Streptococcus pneumoniae is accepted as a leading cause. Although β-lactam-plus-macrolide combination therapy for this disease is recommended in several guidelines, the clinical efficacy of this strategy against pneumococcal pneumonia remains controversial. In this study, we examined the effects of β-lactam-plus-macrolide combination therapy on lethal mouse pneumococcal pneumonia and explored the mechanisms of action in vitro and in vivo We investigated survival, lung bacterial burden, and cellular host responses in bronchoalveolar lavage fluids obtained from mice infected with pneumonia and treated with ceftriaxone, azithromycin, or both in combination. Although in vitro synergy was not observed, significant survival benefits were demonstrated with combination treatment. Lung neutrophil influx was significantly lower in the ceftriaxone-plus-azithromycin-treated group than in the ceftriaxone-treated group, whereas no differences in the lung bacterial burden were observed on day 3 between the ceftriaxone-plus-azithromycin-treated group and the ceftriaxone-treated group. Notably, the analysis of cell surface markers in the ceftriaxone-plus-azithromycin combination group exhibited upregulation of presumed immune checkpoint ligand CD86 and major histocompatibility complex class II in neutrophils and CD11b-positive CD11c-positive (CD11b(+) CD11c(+)) macrophages and dendritic cells, as well as downregulation of immune checkpoint receptors cytotoxic-T lymphocyte-associated antigen 4 and programmed death 1 in T helper and T regulatory cells. Our data demonstrate that the survival benefits of ceftriaxone-plus-azithromycin therapy occur through modulation of immune checkpoints in mouse pneumococcal pneumonia. In addition, immune checkpoint molecules may be a novel target class for future macrolide research.

Comparative Outcome Analysis of Penicillin-Based Versus Fluoroquinolone-Based Antibiotic Therapy for Community-Acquired Pneumonia: A Nationwide Population-Based Cohort Study

Community-acquired pneumonia (CAP) is a common but potentially life-threatening condition, but limited information exists on the effectiveness of fluoroquinolones compared to β-lactams in outpatient settings. We aimed to compare the effectiveness and outcomes of penicillins versus respiratory fluoroquinolones for CAP at outpatient clinics.This was a claim-based retrospective cohort study. Patients aged 20 years or older with at least 1 new pneumonia treatment episode were included, and the index penicillin or respiratory fluoroquinolone therapies for a pneumonia episode were at least 5 days in duration. The 2 groups were matched by propensity scores. Cox proportional hazard models were used to compare the rates of hospitalizations/emergence service visits and 30-day mortality. A logistic model was used to compare the likelihood of treatment failure between the 2 groups.After propensity score matching, 2622 matched pairs were included in the final model. The likelihood of treatment failure of fluoroquinolone-based therapy was lower than that of penicillin-based therapy (adjusted odds ratio [AOR], 0.88; 95% confidence interval [95%CI], 0.77-0.99), but no differences were found in hospitalization/emergence service (ES) visits (adjusted hazard ratio [HR], 1.27; 95% CI, 0.92-1.74) and 30-day mortality (adjusted HR, 0.69; 95% CI, 0.30-1.62) between the 2 groups.The likelihood of treatment failure of fluoroquinolone-based therapy was lower than that of penicillin-based therapy for CAP on an outpatient clinic basis. However, this effect may be marginal. Further investigation into the comparative effectiveness of these 2 treatment options is warranted.

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.

What Is New in Antibiotic Therapy in Community-Acquired Pneumonia? An Evidence-Based Approach Focusing on Combined Therapy

Despite all published literature, controversies remain about the optimal antibiotic treatment in community-acquired pneumonia. The most debated issue is whether it is necessary to empirically start one or two antibiotics, i.e. whether or not to cover atypical agents. A review of the literature published from 2005 to present was completed, searching for new insights in antibiotic treatment in community-acquired pneumonia (CAP) focusing on monotherapy versus combined therapy. Forty-one articles were identified enrolling outpatients, and patients admitted to the ward and to the intensive care unit: 11 were meta-analyses, 8 clinical trials and 22 observational-prospective and retrospective-studies. Although controversies remain in the treatment of CAP, the use of combination therapy seems to be associated with a lower mortality in case of severe CAP that requires intensive care unit (ICU) admission, especially when a beta-lactam-macrolide association is delivered. Moreover, combination therapy is associated with better outcomes-although not always with a lower mortality-in cases of non-ICU patients with risk factors for a poor outcome, bacteraemic pneumococcal pneumonia and high suspicion of infection by atypical agents. In this setting, it appears that the best choice of treatment may be a beta-lactam-macrolide regimen.

The management of severe community acquired pneumonia in the intensive care unit

Severe CAP (SCAP), accounting for 6% of admissions to intensive care units (ICUs) needs early diagnosis and aggressive interventions at the most proximal point of disease presentation. The prognostic scores as the ATS/IDSA rule, the systolic blood pressure, multilobar infiltrates, albumin, respiratory rate, tachycardia, confusion, oxygen and pH or SCAP system are appropriate in early identification of eligible patients requiring admission to ICU. Then the recommended initial resuscitation in SCAP in the ICU consists of fluid volume intake titrated to specific goals after a fluid challenge and hemodynamic optimization. The first selection of antimicrobial therapy should be started in the first hour and would be broad enough to cover all likely pathogens. Combination therapy may be useful in patients with non refractory septic shock and severe sepsis pneumococcal bacteremia as well. After 6 hours the patient would be reevaluated in terms of hemodynamic stability and antibiotic and therapy. Future developments will focus on sepsis biomarkers, molecular diagnostic techniques and the development of novel therapeutic immunomodulaty agents.

In Vitro Fractional Inhibitory Concentration (FIC) Study of Cefixime and Azithromycin Fixed Dose Combination (FDC) Against Respiratory Clinical Isolates

INTRODUCTION

Acute respiratory infections (ARI) contribute to more than 75% of health care seeking in primary health care facilities in India. Respiratory tract infections (RTIs) are managed frequently by β-lactam, macrolide and fluroquinolone class of antibiotics. However, these recommended classes of antibiotic have shown resistance in community settings. Antibiotic combinations may provide broader spectrum not only in terms of coverage but also to overcome multiple resistance mechanisms overcoming individual class limitations.

AIM

The study aimed to determine In vitro interactions interpreted according to calculated fractional inhibitory concentration (FIC) index between cefixime and azithromycin against common respiratory clinical isolates.

MATERIALS AND METHODS

Forty four bacterial respiratory clinical isolates from microbiology department of tertiary care hospital from Mumbai were used to determine the minimum inhibitory concentration (MIC) values of cefixime and azithromycin. Synergy testing of cefixime combination with azithromycin was performed by checkerboard method. Interaction was determined according to calculated FIC index.

RESULTS

MIC values were ranging from 2-128 μg/ml and 0.24-128 μg/ml for cefixime and azithromycin respectively against K.pneumoniae, M.catarrhalis, S.pneumoniae and H.influenzae isolates. All the tested isolates were resistant to cefixime. Azithromycin resistance was noted in all the isolates except six M. catarrhalis isolates. FIC index showed synergy and additive effect in 66% (29/44) and 34% (15/44) all bacterial clinical isolates. Maximum synergy between cefixime and azithromycin was observed against K. pneumoniae in 91% isolates.

CONCLUSION

This is one of the first attempts to check the rationality of fixed dose antibiotic combination of cefixime and azithromycin in India market. Though results of this study cannot be generalized considering the limitations of low sample size and in vitro model, our data provides stepping stone for further validation of cefixime and azithromycin fixed dose combinations (FDCs) in clinical setting by conducting randomized controlled trials. We think that judicious and rational use of FDCs may help to reduce the risk of selection of further drug resistance along with better clinical outcome.

The bacterial pneumonias: a new treatment paradigm

Pneumonia is a common disease that carries a high mortality. Traditionally, pneumonia has been classified and treated according to the setting where the pneumonia develops, namely community-acquired pneumonia, health-care-associated pneumonia, and hospital-acquired pneumonia. This classification was based on the risk of a patient being infected with a hospital-acquired drug-resistant pathogen. A new treatment paradigm has been proposed based on the risk of the patient being infected with a community-acquired drug-resistant pathogen. The risk factors for infection with a community-acquired drug-resistant pathogen include (1) hospitalization for > 2 days during the previous 90 days, (2) antibiotic use during the previous 90 days, (3) nonambulatory status, (4) tube feeds, (5) immunocompromised status, (6) use of acid-suppressive therapy, (7) chronic hemodialysis during the preceding 30 days, (8) positive methicillin-resistant Staphylococcus aureus history within the previous 90 days, and (9) present hospitalization > 2 days. This article reviews this new treatment paradigm and other issues relevant to the diagnosis and management of pneumonia based on information from MEDLINE, EMBASE, and the Cochrane Register of Controlled Trials.

Levofloxacin-ceftriaxone combination attenuates lung inflammation in a mouse model of bacteremic pneumonia caused by multidrug-resistant Streptococcus pneumoniae via inhibition of cytolytic activities of pneumolysin and autolysin

In this study, our objective was to determine whether a synergistic antimicrobial combination in vitro would be beneficial in the downregulation of pneumococcal virulence genes and whether the associated inflammation of the lung tissue induced by multidrug-resistant Streptococcus pneumoniae infection in vivo needs to be elucidated in order to consider this mode of therapy in case of severe pneumococcal infection. We investigated in vivo changes in the expression of these virulence determinants using an efficacious combination determined in previous studies. BALB/c mice were infected with 10(6) CFU of bacteria. Intravenous levofloxacin at 150 mg/kg and/or ceftriaxone at 50 mg/kg were initiated 18 h postinfection; the animals were sacrificed 0 to 24 h after the initiation of treatment. The levels of cytokines, chemokines, and C-reactive protein (CRP) in the serum and lungs, along with the levels of myeloperoxidase and nitric oxide the inflammatory cell count in bronchoalveolar lavage fluid (BALF), changes in pneumolysin and autolysin gene expression and COX-2 and inducible nitric oxide synthase (iNOS) protein expression in the lungs were estimated. Combination therapy downregulated inflammation and promoted bacterial clearance. Pneumolysin and autolysin expression was downregulated, with a concomitant decrease in the expression of COX-2 and iNOS in lung tissue. Thus, the combination of levofloxacin and ceftriaxone can be considered for therapeutic use even in cases of pneumonia caused by drug-resistant isolates.

Burden of antibiotic resistance in common infectious diseases: role of antibiotic combination therapy

Globally, antimicrobial resistance is alarming concern especially in commonly reported disease entities like respiratory tract infection, enteric fever and infections associated with gram-negative bacilli (GNB). Rational use of antimicrobial drugs reported significant decrease in bacterial burden and may also reduce the risk of disease progression. However, at times in particular indication, certain patient and pathogen factor limits the selection and use of specific antibiotic therapy while in some case, due to presence of additional risk factor, aggressive therapy is required to achieve clinical reemission and prevent complications. Delay in start of suitable antibiotic therapy is another imperative factor for treatment failure and rise of drug resistance. With rapidly increasing antibiotic resistance and decline in new antibiotic drug development, the toughest challenge remains to maintain and preserve the efficacy of currently available antibiotics. Therefore, the best rational approach to fight these infections is to 'hit early and hit hard' and kills drug-susceptible bacteria before they become resistant. The preferred approach is to deploy two antibiotics that produce a stronger effect in combination than if either drug were used alone. Various society guidelines in particular indications also justify and recommend the use of combination of antimicrobial therapy. Combination therapies have distinct advantage over monotherapy in terms of broad coverage, synergistic effect and prevention of emergence of drug resistance.

Clinical characteristics of severe community-acquired pneumonia among younger patients: an analysis of 18 years at a community hospital

Unlike elderly patients with community-acquired pneumonia whose outcomes are markedly affected by their background characteristics, it appears that the severity of the infection itself contributes to outcomes in younger patients with community-acquired pneumonia. In order to identify clinical characteristics of severe community-acquired pneumonia in younger patients under 60 years old, among such cases prospectively collected at our hospital over a period of 18 years, those meeting the criteria for severe community-acquired pneumonia, as defined in the Infectious Diseases Society of America/American Thoracic Society Guidelines for community-acquired pneumonia, were retrospectively examined and compared to elderly patients with severe community-acquired pneumonia. Younger patients with severe pneumonia accounted for 12.9% of younger hospitalized patients. Although the incidence of severe pneumonia in younger patients was lower than that in elderly patients, its severity may be underestimated by severity assessment based on the conventional guidelines. Thus, attention is required. While Streptococcus pneumoniae and Legionella species were important causative pathogens, atypical pathogens and viruses were also frequently detected. There were only 11 deaths over a period of 18 years. Based on multivariate analysis, the risk factors for aggravation of community-acquired pneumonia among younger patients were age 50 years or older, diabetes mellitus, chronic liver disease, and Legionella pneumonia. Although the mortality rate from community-acquired pneumonia is extremely low in previously healthy younger patients, outcomes might be poor for patients with underlying diseases and those with rapid progression. Multimodal treatments including respiratory management may be appropriate.

Association of azithromycin with mortality and cardiovascular events among older patients hospitalized with pneumonia

IMPORTANCE

Although clinical practice guidelines recommend combination therapy with macrolides, including azithromycin, as first-line therapy for patients hospitalized with pneumonia, recent research suggests that azithromycin may be associated with increased cardiovascular events.

OBJECTIVE

To examine the association of azithromycin use with all-cause mortality and cardiovascular events for patients hospitalized with pneumonia.

DESIGN

Retrospective cohort study comparing older patients hospitalized with pneumonia from fiscal years 2002 through 2012 prescribed azithromycin therapy and patients receiving other guideline-concordant antibiotic therapy.

SETTING

This study was conducted using national Department of Veterans Affairs administrative data of patients hospitalized at any Veterans Administration acute care hospital.

PARTICIPANTS

Patients were included if they were aged 65 years or older, were hospitalized with pneumonia, and received antibiotic therapy concordant with national clinical practice guidelines.

MAIN OUTCOMES AND MEASURES

Outcomes included 30- and 90-day all-cause mortality and 90-day cardiac arrhythmias, heart failure, myocardial infarction, and any cardiac event. Propensity score matching was used to control for the possible effects of known confounders with conditional logistic regression.

RESULTS

Of 73,690 patients from 118 hospitals identified, propensity-matched groups were composed of 31,863 patients exposed to azithromycin and 31,863 matched patients who were not exposed. There were no significant differences in potential confounders between groups after matching. Ninety-day mortality was significantly lower in those who received azithromycin (exposed, 17.4%, vs unexposed, 22.3%; odds ratio [OR], 0.73; 95% CI, 0.70-0.76). However, we found significantly increased odds of myocardial infarction (5.1% vs 4.4%; OR, 1.17; 95% CI, 1.08-1.25) but not any cardiac event (43.0% vs 42.7%; OR, 1.01; 95% CI, 0.98-1.05), cardiac arrhythmias (25.8% vs 26.0%; OR, 0.99; 95% CI, 0.95-1.02), or heart failure (26.3% vs 26.2%; OR, 1.01; 95% CI, 0.97-1.04).

CONCLUSIONS AND RELEVANCE

Among older patients hospitalized with pneumonia, treatment that included azithromycin compared with other antibiotics was associated with a lower risk of 90-day mortality and a smaller increased risk of myocardial infarction. These findings are consistent with a net benefit associated with azithromycin use.

Fluoroquinolone- and ceftriaxone-based therapy of community-acquired pneumonia in hospitalized patients: the risk of subsequent isolation of multidrug-resistant organisms

A retrospective cohort study was performed on 175 adult patients treated for community-acquired pneumonia with moxifloxacin or ceftriaxone/azithromycin in a nonintensive care unit. Both cohorts were very similar with regard to a wide range of characteristics including age, severity of disease, comorbidities, length of stay, and mortality. Multidrug-resistant organisms were subsequently isolated from 6 (15%) moxifloxacin-treated patients and 5 (4%) ceftriaxone/azithromycin-treated patients within 90 days after beginning of therapy (P = .026 on logistic regression analysis).

Efficacy of combination therapy with oseltamivir phosphate and azithromycin for influenza: a multicenter, open-label, randomized study

Background

Macrolides have antibiotic and immunomodulatory activities, which may have a favorable effect on the clinical outcome of patients with infections, including influenza. This study aimed to evaluate the effects of combination therapy with an anti-influenza agent, oseltamivir, and a single-dose formulation of azithromycin (AZM), which has been used for influenza-related secondary pneumonia, on influenza patients. The primary endpoint was a change in the expression levels of inflammatory cytokines. Secondary endpoints were the time required for resolution of influenza-related symptoms, incidence of complications, and adverse reactions.

Methods

Patients with seasonal influenza were enrolled in this multicenter, open-label, randomized study. Patients were stratified according to the presence of a high risk factor and were randomized to receive combination therapy with oseltamivir plus an extended-release formulation of AZM (combo-group) or oseltamivir monotherapy (mono-group).

Results

We enrolled 107 patients and randomized them into the mono-group (56 patients) or the combo-group (51 patients). All patients were diagnosed with influenza A infection, and none of the patients had comorbid pneumonia. Statistically significant differences were not observed in the expression levels of inflammatory cytokines and chemokines between the 2 groups. The maximum temperature in the combo-group was lower than that in the mono-group on day 3 through day 5 (p = 0.048), particularly on day 4 (p = 0.037).

Conclusion

To our knowledge, this is the first prospective, randomized, clinical trial of oseltamivir and AZM combination therapy for influenza. Although the difference in inflammatory cytokine expression level was not statistically significant, combination therapy showed an early resolution of some symptoms.

Name of registry

University hospital Medical Information Network (UMIN).

Trial Registration no

UMIN000005371

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.

Initial use of one or two antibiotics for critically ill patients with community-acquired pneumonia: impact on survival and bacterial resistance

INTRODUCTION

Several guidelines recommend initial empirical treatment with two antibiotics instead of one to decrease mortality in community-acquired pneumonia (CAP) requiring intensive-care-unit (ICU) admission. We compared the impact on 60-day mortality of using one or two antibiotics. We also compared the rates of nosocomial pneumonia and multidrug-resistant bacteria.

METHODS

This is an observational cohort study of 956 immunocompetent patients with CAP admitted to ICUs in France and entered into a prospective database between 1997 and 2010.

RESULTS

Initial adequate antibiotic therapy was significantly associated with better survival (subdistribution hazard ratio (sHR), 0.63; 95% confidence interval (95% CI), 0.42 to 0.94; P = 0.02); this effect was strongest in patients with Streptococcus pneumonia CAP (sHR, 0.05; 95% CI, 0.005 to 0.46; p = 0.001) or septic shock (sHR: 0.62; 95% CI 0.38 to 1.00; p = 0.05). Dual therapy was associated with a higher frequency of initial adequate antibiotic therapy. However, no difference in 60-day mortality was found between monotherapy (β-lactam) and either of the two dual-therapy groups (β-lactam plus macrolide or fluoroquinolone). The rates of nosocomial pneumonia and multidrug-resistant bacteria were not significantly different across these three groups.

CONCLUSIONS

Initial adequate antibiotic therapy markedly decreased 60-day mortality. Dual therapy improved the likelihood of initial adequate therapy but did not predict decreased 60-day mortality. Dual therapy did not increase the risk of nosocomial pneumonia or multidrug-resistant bacteria.

Effect of clarithromycin in experimental empyema by multidrug-resistant Pseudomonas aeruginosa

Evidence from a recent randomized study of our group suggests that intravenous clarithromycin resulted in earlier resolution of ventilator-associated pneumonia. The need to understand the mechanism of action of clarithromycin guided to the study of a model of experimental empyema by multidrug-resistant Pseudomonas aeruginosa in 40 rabbits. Animals were randomized into controls (group A); treatment with clarithromycin (group B); treatment with piperacillin/tazobactam (group C); and treatment with both agents (group D). Pleural fluid was collected at regular time intervals for quantitative culture, estimation of cell apoptosis and of concentrations of tumour necrosis factor-alpha (TNFα). After 7 days, animals were euthanized for estimation of tissue growth. Bacterial growth in the pleural fluid of group D was significantly decreased compared with the other groups on day 5. Lung growth of group D was lower than group A. That was also the case of cytokine stimulation by pleural fluid samples on U937 monocytes. It is concluded that administration of clarithromycin enhanced the antimicrobial efficacy of piperacillin/tazobactam and decreased bacterial growth in the pleural fluid and in tissues. It also attenuated the pro-inflammatory phenomena induced by the β-lactam.

Comparative effectiveness of empiric β-lactam monotherapy and β-lactam-macrolide combination therapy in children hospitalized with community-acquired pneumonia

OBJECTIVE

To determine the comparative effectiveness of β-lactam monotherapy and β-lactam and macrolide combination therapy on clinical outcomes in the treatment of children hospitalized with community-acquired pneumonia (CAP).

STUDY DESIGN

This multicenter retrospective cohort study included children aged 1-18 years who were hospitalized with CAP and received β-lactam antibiotic therapy either alone or in combination with a macrolide. Data were obtained from the Pediatric Health Information System. Associations between empiric antibiotic therapy and hospital readmission for the same episode of pneumonia were estimated using exact logistic regression. Associations between empiric antibiotic therapy and length of hospital stay were estimated using a generalized estimating equation with negative binomial distribution.

RESULTS

There were 20 743 patients hospitalized with CAP. Of these, 24% received β-lactam and macrolide combination therapy on admission. Compared with children who received β-lactam monotherapy, children who received β-lactam plus macrolide combination therapy were 20% less likely to stay in the hospital an additional day (adjusted relative risk 0.80; 95% CI, 0.75-0.86) but did not have a different readmission rate (relative risk 0.69; 95% CI, 0.41-1.12). An effect of combination treatment on reduced length of stay was not evident in children <6 years of age but increased with increasing age groups thereafter.

CONCLUSION

School-aged patients hospitalized with CAP who received β-lactam plus macrolide combination therapy have a shorter length of stay and similar rates of readmission compared with school-aged patients who receive β-lactam monotherapy.

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.

Audit of physicians' adherence to a preprinted order set for community-acquired pneumonia

BACKGROUND

Community-acquired pneumonia is the seventh leading cause of death in Canada. Previous studies have shown reductions in both mortality rate and length of hospital stay with the use of guideline-concordant empiric therapy and standardized preprinted orders.

OBJECTIVES

The primary objective was to determine adherence to the preprinted order for community-acquired pneumonia at the University Hospital of Northern British Columbia (UHNBC). The study also had the following secondary objectives: to assess the appropriateness of prescribing of levofloxacin in relation to institutional recommendations; to determine adherence with recent guidelines from the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) for the treatment of community-acquired pneumonia; and to determine all-cause mortality, duration of IV antibiotic therapy, and length of stay for the various regimens reviewed.

METHODS

A retrospective observational chart review was conducted of patients with community-acquired pneumonia who were admitted between November 2007 and February 2008. Exclusion criteria were designed to eliminate patients who did not have this condition. Descriptive statistics were used to assess adherence with the preprinted order. Secondary outcomes were analyzed with the Pearson χ(2) test, t tests, and analysis of variance.

RESULTS

In total, the charts for 113 patients were reviewed, and 58 patients were included in the study. The preprinted order for community-acquired pneumonia was used for 25 (43%) of the 58 patients; however, for only 4 (7%) of these admissions were all sections of the preprinted order used correctly. No statistically significant differences in length of stay were found for any of the antibiotic combinations assessed. However, the proportion of patients treated according to the IDSA-ATS guidelines was significantly greater when the preprinted order was used (p = 0.012). In addition, use of the preprinted order encouraged assessment of the patient's pneumococcal vaccination status (9 [25%] of 25 patients versus 3 [9%] of 33 patients) and utilization of the pneumonia severity index (13 [52%] of 25 patients versus 0 [0%] of 33 patients).

CONCLUSION

The preprinted order for community-acquired pneumonia at UHNBC was not being utilized to its fullest. However, when it was used, it increased guideline-concordant empiric therapy and encouraged assessment of patients' pneumococcal vaccination status and pneumonia severity index.

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.

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.

Antimicrobial therapy of sepsis and septic shock--when are two drugs better than one?

In clinical practice, physicians frequently use combination therapy despite the conflicting evidence for its effectiveness. The results of recent studies have contributed to our understanding of this important issue. In this article, we examine the evidence for, or against, the use of combination drug therapy compared with monotherapy in the management of serious infections, sepsis, and septic shock.