[Efficacy and safety of pristinamycin vs amoxicillin in community acquired pneumonia in adults]

Streptogramins for the treatment of infections caused by Gram-positive pathogens

INTRODUCTION

Streptogramins (pristinamycin and quinupristin-dalfopristin) can be interesting options for the treatment of infections due to Gram-positive cocci, especially multidrug-resistant isolates.

AREAS COVERED

This review provides an updated overview of structural and activity characteristics, mechanisms of action and resistance, pharmacokinetic/pharmacodynamic, and clinical use of streptogramins.

EXPERT OPINION

The streptogramin antibiotics act by inhibition of the bacterial protein synthesis. They are composed of two chemically distinct compounds, namely type A and type B streptogramins, which exert a rapid bactericidal activity against a wide range of Gram-positive bacteria (including methicillin-resistant staphylococci and vancomycin-resistant enterococci). Several mechanisms of resistance have been identified in staphylococci and enterococci but the prevalence of streptogramin resistance among clinical isolates remains very low. Even if only a few randomized clinical trials have been conducted, the efficacy of pristinamycin has been largely demonstrated with an extensive use for 50 years in France and some African countries. Despite its effectiveness in the treatment of severe Gram-positive bacterial infections demonstrated in several studies and the low rate of reported resistance, the clinical use of quinupristin-dalfopristin has remained limited, mainly due to its poor tolerance. Altogether, streptogramins (especially pristinamycin) can be considered as potential alternatives for the treatment of Gram-positive infections.

Managing community acquired pneumonia in the elderly - the next generation of pharmacotherapy on the horizon

INTRODUCTION

Community acquired pneumonia (CAP) is associated with high rates of morbidity and mortality, especially among the elderly. Antibiotic treatment for CAP in the elderly is particularly challenging for many reasons, including compliance issues, immunosuppression, polypharmacy and antimicrobial resistance. There are few available antibiotics that are able to address these concerns. Areas covered: After a systematic review of the current literature, we describe seven novel antibiotics that are currently in advanced stages of development (phase 3 and beyond) and show promise for the treatment of CAP in those over the age of 65. These antibiotics are: Solithromycin, Pristinamycin, Nemonaxacin, Lefamulin, Omadacycline, Ceftobiprole and Delafloxacin. Using a novel conceptual framework designed by the present authors, known as the 'San Antonio NIPS model', we evaluate their strengths and weaknesses based on their ability to address the unique challenges that face the elderly. Expert opinion: All seven antibiotics have potential value for effective utilization in the elderly, but to varying degrees based on their NIPS model score. The goal of this model is to reorganize a clinician's focus on antibiotic choices in the elderly and bring attention to a seldom discussed topic that may potentially become a health-care crisis in the next decade.

Antibiotics for community-acquired pneumonia in adult outpatients

BACKGROUND

Lower respiratory tract infection (LRTI) is the third leading cause of death worldwide and the first leading cause of death in low-income countries. Community-acquired pneumonia (CAP) is a common condition that causes a significant disease burden for the community, particularly in children younger than five years, the elderly and immunocompromised people. Antibiotics are the standard treatment for CAP. However, increasing antibiotic use is associated with the development of bacterial resistance and side effects for the patient. Several studies have been published regarding optimal antibiotic treatment for CAP but many of these data address treatments in hospitalised patients. This is an update of our 2009 Cochrane Review and addresses antibiotic therapies for CAP in outpatient settings.

OBJECTIVES

To compare the efficacy and safety of different antibiotic treatments for CAP in participants older than 12 years treated in outpatient settings with respect to clinical, radiological and bacteriological outcomes.

SEARCH METHODS

We searched CENTRAL (2014, Issue 1), MEDLINE (January 1966 to March week 3, 2014), EMBASE (January 1974 to March 2014), CINAHL (2009 to March 2014), Web of Science (2009 to March 2014) and LILACS (2009 to March 2014).

SELECTION CRITERIA

We looked for randomised controlled trials (RCTs), fully published in peer-reviewed journals, of antibiotics versus placebo as well as antibiotics versus another antibiotic for the treatment of CAP in outpatient settings in participants older than 12 years of age. However, we did not find any studies of antibiotics versus placebo. Therefore, this review includes RCTs of one or more antibiotics, which report the diagnostic criteria and describe the clinical outcomes considered for inclusion in this review.

DATA COLLECTION AND ANALYSIS

Two review authors (LMB, TJMV) independently assessed study reports in the first publication. In the 2009 update, LMB performed study selection, which was checked by TJMV and MMK. In this 2014 update, two review authors (SP, SM) independently performed and checked study selection. We contacted trial authors to resolve any ambiguities in the study reports. We compiled and analysed the data. We resolved differences between review authors by discussion and consensus.

MAIN RESULTS

We included 11 RCTs in this review update (3352 participants older than 12 years with a diagnosis of CAP); 10 RCTs assessed nine antibiotic pairs (3321 participants) and one RCT assessed four antibiotics (31 participants) in people with CAP. The study quality was generally good, with some differences in the extent of the reporting. A variety of clinical, bacteriological and adverse events were reported. Overall, there was no significant difference in the efficacy of the various antibiotics. Studies evaluating clarithromycin and amoxicillin provided only descriptive data regarding the primary outcome. Though the majority of adverse events were similar between all antibiotics, nemonoxacin demonstrated higher gastrointestinal and nervous system adverse events when compared to levofloxacin, while cethromycin demonstrated significantly more nervous system side effects, especially dysgeusia, when compared to clarithromycin. Similarly, high-dose amoxicillin (1 g three times a day) was associated with higher incidence of gastritis and diarrhoea compared to clarithromycin, azithromycin and levofloxacin.

AUTHORS' CONCLUSIONS

Available evidence from recent RCTs is insufficient to make new evidence-based recommendations for the choice of antibiotic to be used for the treatment of CAP in outpatient settings. Pooling of study data was limited by the very low number of studies assessing the same antibiotic pairs. Individual study results do not reveal significant differences in efficacy between various antibiotics and antibiotic groups. However, two studies did find significantly more adverse events with use of cethromycin as compared to clarithromycin and nemonoxacin when compared to levofloxacin. Multi-drug comparisons using similar administration schedules are needed to provide the evidence necessary for practice recommendations. Further studies focusing on diagnosis, management, cost-effectiveness and misuse of antibiotics in CAP and LRTI are warranted in high-, middle- and low-income countries.

Assessment of bias in outcomes reported in trials on pneumonia: a systematic review

Subjective outcomes may exaggerate intervention effects compared to objectively measured outcomes. We compared effect estimates for clinical failure and all-cause mortality clinical trials of antibiotic treatment for pneumonia. A systematic review of randomized controlled trials assessing adults with pneumonia, comparing different antibiotics, published between 2005 and 2012 was undertaken. We compared the intervention to the control arm. The all-cause mortality in the intention-to-treat population and clinical failure as defined by the study investigators for the primary analyzed population were the primary outcomes examined. Risk ratios (RRs) with 95 % confidence intervals (CIs) were pooled, using a fixed effect model. Meta-regression was used to examine the impact of clinical failure on the mortality effect size. Thirty-six trials were included, of which 30 were industry-sponsored and 30 were non-inferiority trials. There was no difference between the effect on mortality for intervention versus control (RR 1.02, 95 % CI 0.91-1.16) and clinical failure (RR 1.01, 95 % CI 0.93-1.10), without significant heterogeneity in both analyses. In double-blind trials with adequate sequence generation and concealment, there was a significant advantage to the intervention for clinical failure (RR 0.86, 95 % CI 0.76-0.98), but not for mortality (RR 0.96, 95 % CI 0.76-1.21). RRs for clinical failure did not explain the variability in the RRs for mortality significantly, with a meta-regression coefficient of 0.32 (95 % CI -0.21-0.85). In non-inferiority trials of antibiotic treatment for pneumonia, we did not find evidence for bias induced by the use of a subjective outcome overall. The small number of trials without sponsorship precludes an adequate assessment of sponsorship effects.

Empiric antibiotic coverage of atypical pathogens for community-acquired pneumonia in hospitalized adults

BACKGROUND

Community-acquired pneumonia (CAP) is caused by various pathogens, traditionally divided into 'typical' and 'atypical'. Initial antibiotic treatment of CAP is usually empirical, customarily covering both typical and atypical pathogens. To date, no sufficient evidence exists to support this broad coverage, while limiting coverage is bound to reduce toxicity, resistance and expense.

OBJECTIVES

The main objective was to estimate the mortality and proportion with treatment failure using regimens containing atypical antibiotic coverage compared to those that had typical coverage only. Secondary objectives included the assessment of adverse events.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) Issue 3, 2012 which includes the Acute Respiratory Infection Group's Specialized Register, MEDLINE (January 1966 to April week 1, 2012) and EMBASE (January 1980 to April 2012).

SELECTION CRITERIA

Randomized controlled trials (RCTs) of adult patients hospitalized due to CAP, comparing antibiotic regimens with atypical coverage (quinolones, macrolides, tetracyclines, chloramphenicol, streptogramins or ketolides) to a regimen without atypical antibiotic coverage.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias and extracted data from included trials. We estimated risk ratios (RRs) with 95% confidence intervals (CIs). We assessed heterogeneity using a Chi(2) test.

MAIN RESULTS

We included 28 trials, encompassing 5939 randomized patients. The atypical antibiotic was administered as monotherapy in all but three studies. Only one study assessed a beta-lactam combined with a macrolide compared to the same beta-lactam. There was no difference in mortality between the atypical arm and the non-atypical arm (RR 1.14; 95% CI 0.84 to 1.55), RR < 1 favors the atypical arm. The atypical arm showed an insignificant trend toward clinical success and a significant advantage to bacteriological eradication, which disappeared when evaluating methodologically high quality studies alone. Clinical success for the atypical arm was significantly higher for Legionella pneumophilae (L. pneumophilae) and non-significantly lower for pneumococcal pneumonia. There was no significant difference between the groups in the frequency of (total) adverse events, or those requiring discontinuation of treatment. However, gastrointestinal events were less common in the atypical arm (RR 0.70; 95% CI 0.53 to 0.92). Although the trials assessed different antibiotics, no significant heterogeneity was detected in the analyses.

AUTHORS' CONCLUSIONS

No benefit of survival or clinical efficacy was shown with empirical atypical coverage in hospitalized patients with CAP. This conclusion relates mostly to the comparison of quinolone monotherapy to beta-lactams. Further trials, comparing beta-lactam monotherapy to the same combined with a macrolide, should be performed.

Antibiotics for community acquired pneumonia in adult outpatients

BACKGROUND

Community-acquired pneumonia (CAP), the sixth most common cause of death worldwide, is a common condition representing a significant disease burden for the community, particularly in the elderly. Antibiotics are helpful in treating CAP and are the standard treatment. CAP contributes significantly to antibiotic use, which is associated with the development of bacterial resistance and side-effects. Several studies have been published concerning treatment for CAP. Available data arises mainly hospitalized patients studies. This is an update of our 2004 Cochrane Review.

OBJECTIVES

To summarize current evidence from randomized controlled trials (RCTs) concerning the efficacy of different antibiotic treatments for CAP in participants older than 12.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2009, issue 1) which contains the Cochrane Acute Respiratory Infections Group's Specialized Register; MEDLINE (January 1966 to February week 2, 2009), and EMBASE (January 1974 to February 2009).

SELECTION CRITERIA

RCTs in which one or more antibiotics were tested for the treatment of CAP in ambulatory adolescents or adults. Studies testing one or more antibiotics and reporting the diagnostic criteria as well as the clinical outcomes achieved, were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors (LMB, TJMV) independently assessed study reports in the first publication. In this update, LMB performed study selection, which was checked by TJMV and MMK. Study authors were contacted to resolve any ambiguities in the study reports. Data were compiled and analyzed. Differences between review authors were resolved by discussion and consensus.

MAIN RESULTS

Six RCTs assessing five antibiotic pairs (1857 participants aged 12 years and older diagnosed with CAP) were included. The study quality was generally good, with some differences in the extent of the reporting. A variety of clinical, radiological and bacteriological diagnostic criteria and outcomes were reported. Overall, there was no significant difference in the efficacy of the various antibiotics.

AUTHORS' CONCLUSIONS

Currently available evidence from RCTs is insufficient to make evidence-based recommendations for the choice of antibiotic to be used for the treatment of CAP in ambulatory patients. Pooling of study data was limited by the very low number of studies assessing the same antibiotic pairs. Individual study results do not reveal significant differences in efficacy between various antibiotics and antibiotic groups. Multi-drug comparisons using similar administration schedules are needed to provide the evidence necessary for practice recommendations.

[Antibiotherapy for acute CAP in adults]

Community acquired pneumonia is one of the most frequent infections. With time, bacterial epidemiology and bacterial resistance evolve and new antibiotics become available. So an up-date on adequate antibiotic use is necessary. We reviewed the epidemiology of pneumonia and the evolution of bacterial resistance. We also collected data on new antibiotics which can be used for this infection such as levofloxacin, moxifloxacin, telithromycin, and pristinamycin. All these drugs are effective on bacteria involved in pneumonia. At this time, only few Streptococcus pneumoniae strains have developed resistance to these drugs. However, resistance to fluoroquinolones is not easily detected with common laboratory techniques. There is no effectiveness difference between the 2 new fluoroquinolones (levofloxacin, moxifloxacin) in clinical studies. However, in bacteriological and pharmacological studies, moxifloxacin seems to be more effective than levofloxacin (500 mg/day). For the treatment of pneumonia due to Legionella pneumophila, fluoroquinolones are now widely recommended. For Streptococcus pneumonia, amoxicillin remain the drug of choice, even for bacteria with a decreased susceptibility to penicillin. The importance of treating atypical pathogens remains to be documented.

Pneumonies aiguës communautaires : analyse critique des essais cliniques

Optimal antibiotic treatment of community-acquired pneumonia (CAP) remains controversial. The clinical impact of S. pneumoniae resistance to macrolides is well documented. By contrast high dosage amoxicillin (1 g tid) remains active against such strains and no failure has been reported. The aim of this paper was to review clinical trials in community-acquired pneumonia, published from January 1, 1999, to December 31, 2005. One hundred seventy-three articles were collected, using Medline, 35 of which were analyzed, and 16 finally used. Telithromycin and pristinamycin may be used in mild to moderate CAP. Anti-pneumococcal fluoroquinolones such as levofloxacin and moxifloxacin may be used in at risk patients, but levofloxacin has only been investigated in patients with severe CAP and patients with Legionnaire's disease. Amoxicillin 1 g tid remains the drug of choice for pneumococcal CAP.

[Resistance of infectious agents involved in low respiratory tract infections in France]

This review concerning the major lower respiratory tract pathogens in France has for aim to describe the epidemiology of resistance to beta-lactams, macrolides, ketolides, and fluoroquinolones especially in Streptococcus pneumoniae and Haemophilus influenzae. It should also provide new insights on the mechanisms of acquired resistance and the level of resistance conferred, highlighting the related ecological impact. In the context of this XVth consensus conference, this review should contribute to the elaboration of guidelines for the treatment of lower respiratory tract infections in adults.