Antibiotics for community acquired pneumonia in adult outpatients

Antimicrobial mitochondrial reactive oxygen species induction by lung epithelial immunometabolic modulation

Pneumonia is a worldwide threat, making discovery of novel means to combat lower respiratory tract infection an urgent need. Manipulating the lungs' intrinsic host defenses by therapeutic delivery of certain pathogen-associated molecular patterns protects mice against pneumonia in a reactive oxygen species (ROS)-dependent manner. Here we show that antimicrobial ROS are induced from lung epithelial cells by interactions of CpG oligodeoxynucleotides (ODN) with mitochondrial voltage-dependent anion channel 1 (VDAC1). The ODN-VDAC1 interaction alters cellular ATP/ADP/AMP localization, increases delivery of electrons to the electron transport chain (ETC), increases mitochondrial membrane potential (ΔΨm), differentially modulates ETC complex activities and consequently results in leak of electrons from ETC complex III and superoxide formation. The ODN-induced mitochondrial ROS yield protective antibacterial effects. Together, these studies identify a therapeutic metabolic manipulation strategy to broadly protect against pneumonia without reliance on antibiotics.

Antimicrobial mitochondrial reactive oxygen species induction by lung epithelial metabolic reprogramming

Pneumonia is a worldwide threat, making discovery of novel means to combat lower respiratory tract infections an urgent need. We have previously shown that manipulating the lungs' intrinsic host defenses by therapeutic delivery of a unique dyad of pathogen-associated molecular patterns protects mice against pneumonia in a reactive oxygen species (ROS)-dependent manner. Here we show that antimicrobial ROS are induced from lung epithelial cells by interactions of CpG oligodeoxynucleotides (ODNs) with mitochondrial voltage-dependent anion channel 1 (VDAC1) without dependence on Toll-like receptor 9 (TLR9). The ODN-VDAC1 interaction alters cellular ATP/ADP/AMP localization, increases delivery of electrons to the electron transport chain (ETC), enhances mitochondrial membrane potential (Δ Ψm ), and differentially modulates ETC complex activities. These combined effects promote leak of electrons from ETC complex III, resulting in superoxide formation. The ODN-induced mitochondrial ROS yield protective antibacterial effects. Together, these studies identify a therapeutic metabolic manipulation strategy that has the potential to broadly protect patients against pneumonia during periods of peak vulnerability without reliance on currently available antibiotics.

Author Summary

Pneumonia is a major cause of death worldwide. Increasing antibiotic resistance and expanding immunocompromised populations continue to enhance the clinical urgency to find new strategies to prevent and treat pneumonia. We have identified a novel inhaled therapeutic that stimulates lung epithelial defenses to protect mice against pneumonia in a manner that depends on production of reactive oxygen species (ROS). Here, we report that the induction of protective ROS from lung epithelial mitochondria occurs following the interaction of one component of the treatment, an oligodeoxynucleotide, with the mitochondrial voltage-dependent anion channel 1. This interaction alters energy transfer between the mitochondria and the cytosol, resulting in metabolic reprogramming that drives more electrons into the electron transport chain, then causes electrons to leak from the electron transport chain to form protective ROS. While antioxidant therapies are endorsed in many other disease states, we present here an example of therapeutic induction of ROS that is associated with broad protection against pneumonia without reliance on administration of antibiotics.

The REMAP-CAP (Randomized Embedded Multifactorial Adaptive Platform for Community-acquired Pneumonia) Study. Rationale and Design

There is broad interest in improved methods to generate robust evidence regarding best practice, especially in settings where patient conditions are heterogenous and require multiple concomitant therapies. Here, we present the rationale and design of a large, international trial that combines features of adaptive platform trials with pragmatic point-of-care trials to determine best treatment strategies for patients admitted to an intensive care unit with severe community-acquired pneumonia. The trial uses a novel design, entitled "a randomized embedded multifactorial adaptive platform." The design has five key features: 1) randomization, allowing robust causal inference; 2) embedding of study procedures into routine care processes, facilitating enrollment, trial efficiency, and generalizability; 3) a multifactorial statistical model comparing multiple interventions across multiple patient subgroups; 4) response-adaptive randomization with preferential assignment to those interventions that appear most favorable; and 5) a platform structured to permit continuous, potentially perpetual enrollment beyond the evaluation of the initial treatments. The trial randomizes patients to multiple interventions within four treatment domains: antibiotics, antiviral therapy for influenza, host immunomodulation with extended macrolide therapy, and alternative corticosteroid regimens, representing 240 treatment regimens. The trial generates estimates of superiority, inferiority, and equivalence between regimens on the primary outcome of 90-day mortality, stratified by presence or absence of concomitant shock and proven or suspected influenza infection. The trial will also compare ventilatory and oxygenation strategies, and has capacity to address additional questions rapidly during pandemic respiratory infections. As of January 2020, REMAP-CAP (Randomized Embedded Multifactorial Adaptive Platform for Community-acquired Pneumonia) was approved and enrolling patients in 52 intensive care units in 13 countries on 3 continents. In February, it transitioned into pandemic mode with several design adaptations for coronavirus disease 2019. Lessons learned from the design and conduct of this trial should aid in dissemination of similar platform initiatives in other disease areas.Clinical trial registered with www.clinicaltrials.gov (NCT02735707).

Teaching Shared Decision Making to Family Medicine Residents: A Descriptive Study of a Web-Based Tutorial

BACKGROUND

DECISION+2, a Web-based tutorial, was designed to train family physicians in shared decision making (SDM) regarding the use of antibiotics for acute respiratory infections (ARIs). It is currently mandatory for second-year family medicine residents at Université Laval, Quebec, Canada. However, little is known about how such tutorials are used, their effect on knowledge scores, or how best to assess resident participation.

OBJECTIVE

The objective of our study was to describe the usage of this Web-based training platform by family medicine residents over time, evaluate its effect on their knowledge scores, and identify what kinds of data are needed for a more comprehensive analysis of usage and knowledge acquisition.

METHODS

We identified, collected, and analyzed all available data about participation in and current usage of the tutorial and its before-and-after 10-item knowledge test. Residents were separated into 3 log-in periods (2012-2013, 2013-2014, and 2014-2015) depending on the day of their first connection. We compared residents' participation rates between entry periods (Cochran-Armitage test), assessed the mean rank of the difference in total scores and category scores between pre- and posttest (Wilcoxon signed-rank test), and compared frequencies of each. Subsequent to analyses, we identified types of data that would have provided a more complete picture of the usage of the program and its effect on knowledge scores.

RESULTS

The tutorial addresses 3 knowledge categories: diagnosing ARIs, treating ARIs, and SDM regarding the use of antibiotics for treating ARIs. From July 2012 to July 2015, all 387 second-year family medicine residents were eligible to take the Web-based tutorial. Out of the 387 eligible residents, 247 (63.8%) logged in at least once. Their participation rates varied between entry periods, most significantly between the 2012-2013 and 2013-2014 cohorts (P=.006). For the 109 out of 387 (28.2%) residents who completed the tutorial and both tests, total and category scores significantly improved between pre- and posttest (all P values <.001). However, the frequencies of those answering correctly on 2 of the 3 SDM questions did not increase significantly (P>.99, P=.25). Distribution of pre- or posttest total and category scores did not increase between entry periods (all P values >.1). Available data were inadequate for evaluating the associations between the tutorial and its impact on the residents' scores and therefore could tell us little about its effect on increasing their knowledge.

CONCLUSION

Residents' use of this Web-based tutorial appeared to increase between entry periods following the changes to the SDM program, and the tutorial seemed less effective for increasing SDM knowledge scores than for diagnosis or treatment scores. However, our results also highlight the need to improve data availability before participation in Web-based SDM tutorials can be properly evaluated or knowledge scores improved.

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.

Differences in distribution and drug sensitivity of pathogens in lower respiratory tract infections between general wards and RICU

BACKGROUND

Lower respiratory tract infections (LRTIs) are common among patients in hospitals worldwide, especially in patients over the age of 60. This study investigates the differences in distribution and drug sensitivity of pathogens in LRTIs.

METHODS

The clinical and laboratory data of 4,762 LRTI patients in the general ward and respiratory intensive care unit (RICU) of Xiangya Hospital (Changsha) were retrospectively analyzed.

RESULTS

The infection rate of Gram-negative bacteria was significantly higher than that of Gram-positive bacteria in both the general ward and RICU (P<0.05). The incidence of Gram-negative bacteria infection was significantly higher in the RICU than in the general ward (P<0.05), whereas the incidence of Gram-positive bacteria infection is less in the RICU than in the general ward (P<0.05). In the general ward, the incidence of Gram-negative bacteria infection significantly increased (P<0.05) over time, whereas the incidence of Gram-positive bacteria infection significantly decreased from 1996 to 2011 (P<0.05). In the RICU, the incidence of Gram-positive bacteria infection decreased, while Gram-negative bacteria infections increased without statistical significance (P>0.05). Staphylococcus pneumoniae and Staphylococcus aureus were found to be the predominant Gram-positive strains in the general ward (34.70-41.18%) and RICU (41.66-54.87%), respectively (P>0.05). Pseudomonas aeruginosa and Acinetobacter baumannii were the predominant gram negative strains in the general ward (19.17-21.09%) and RICU (29.60-33.88%), respectively (P>0.05). Streptococcus pneumoniae is sensitive to most antibiotics with a sensitivity of more than 70%. Staphylococcus aureus is highly sensitive to vancomycin (100%), linezolid (100%), chloramphenicol (74.36-82.19%), doxycycline (69.57-77.33%), and sulfamethoprim (67.83-72.46%); however, its sensitivity to other antibiotics is low and decreased each year. Sensitivity of Pseudomonas aeruginosa to most β-lactam, aminoglycoside, and quinolone group antibiotics decreased each year.

CONCLUSIONS

The distribution and drug sensitivity of LRTI pathogens exhibit a high divergence between the general ward and RICU. Streptococcus pneumoniae may not be the predominant pathogen in LRTIs in some areas of China.

Evaluation of yield of currently available diagnostics by sample type to optimize detection of respiratory pathogens in patients with a community-acquired pneumonia

BACKGROUND

For the detection of respiratory pathogens, the sampling strategy may influence the diagnostic yield. Ideally, samples from the lower respiratory tract are collected, but they are difficult to obtain.

OBJECTIVES

In this study, we compared the diagnostic yield in sputum and oropharyngeal samples (OPS) for the detection of respiratory pathogens in patients with community-acquired pneumonia (CAP), with the objective to optimize our diagnostic testing algorithm.

METHODS

Matched sputum samples, OPS, blood cultures, serum, and urine samples were taken from patients (>18 years) with CAP and tested for the presence of possible respiratory pathogens using bacterial cultures, PCR for 17 viruses and five bacteria and urinary antigen testing.

RESULTS

When using only conventional methods, that is, blood cultures, sputum culture, urinary antigen tests, a pathogen was detected in 49·6% of patients (n = 57). Adding molecular detection assays increased the yield to 80%. A pathogen was detected in 77 of the 115 patients in OPS or sputum samples by PCR. The sensitivity of the OPS was lower than that of the sputum samples (57% versus 74%). In particular, bacterial pathogens were more often detected in sputum samples. The sensitivity of OPS for the detection of most viruses was higher than in sputum samples (72% versus 66%), except for human rhinovirus and respiratory syncytial virus.

CONCLUSION

Addition of PCR on both OPS and sputum samples significantly increased the diagnostic yield. For molecular detection of bacterial pathogens, a sputum sample is imperative, but for detection of most viral pathogens, an OPS is sufficient.

Chest radiographs for acute lower respiratory tract infections

BACKGROUND

Acute lower respiratory tract infections (LRTIs) (e.g. pneumonia) are a major cause of morbidity and mortality and management focuses on early treatment. Chest radiographs (X-rays) are one of the commonly used strategies. Although radiological facilities are easily accessible in high-income countries, access can be limited in low-income countries. The efficacy of chest radiographs as a tool in the management of acute LRTIs has not been determined. Although chest radiographs are used for both diagnosis and management, our review focuses only on management.

OBJECTIVES

To assess the effectiveness of chest radiographs in addition to clinical judgement, compared to clinical judgement alone, in the management of acute LRTIs in children and adults.

SEARCH METHODS

We searched CENTRAL 2013, Issue 1; MEDLINE (1948 to January week 4, 2013); EMBASE (1974 to February 2013); CINAHL (1985 to February 2013) and LILACS (1985 to February 2013). We also searched NHS EED, DARE, ClinicalTrials.gov and WHO ICTRP (up to February 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of chest radiographs versus no chest radiographs in acute LRTIs in children and adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the inclusion criteria, extracted data and assessed risk of bias. A third review author compiled the findings and any discrepancies were discussed among all review authors. We used the standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

Two RCTs involving 2024 patients (1502 adults and 522 children) were included in this review. Both RCTs excluded patients with suspected severe disease. It was not possible to pool the results due to incomplete data. Both included trials concluded that the use of chest radiographs did not result in a better clinical outcome (duration of illness and of symptoms) for patients with acute LRTIs. In the study involving children in South Africa, the median time to recovery was seven days (95% confidence interval (CI) six to eight days (radiograph group) and six to nine days (control group)), P value = 0.50, log-rank test) and the hazard ratio for recovery was 1.08 (95% CI 0.85 to 1.34). In the study with adult participants in the USA, the average duration of illness was 16.9 days versus 17.0 days (P value > 0.05) in the radiograph and no radiograph groups respectively. This result was not statistically significant and there were no significant differences in patient outcomes between the groups with or without chest radiograph.The study in adults also reports that chest radiographs did not affect the frequencies with which clinicians ordered return visits or antibiotics. However, there was a benefit of chest radiographs in a subgroup of the adult participants with an infiltrate on their radiograph, with a reduction in length of illness (16.2 days in the group allocated to chest radiographs and 22.6 in the non-chest radiograph group, P < 0.05), duration of cough (14.2 versus 21.3 days, P < 0.05) and duration of sputum production (8.5 versus 17.8 days, P < 0.05). The authors mention that this difference in outcome between the intervention and control group in this particular subgroup only was probably a result of "the higher proportion of patients treated with antibiotics when the radiograph was used in patient care".Hospitalisation rates were only reported in the study involving children and it was found that a higher proportion of patients in the radiograph group (4.7%) required hospitalisation compared to the control group (2.3%) with the result not being statistically significant (P = 0.14). None of the trials report the effect on mortality, complications of infection or adverse events from chest radiographs. Overall, the included studies had a low or unclear risk for blinding, attrition bias and reporting bias, but a high risk of selection bias. Both trials had strict exclusion criteria which is important but may limit the clinical practicability of the results as participants may not reflect those presenting in clinical practice.

AUTHORS' CONCLUSIONS

Data from two trials suggest that routine chest radiography does not affect the clinical outcomes in adults and children presenting to a hospital with signs and symptoms suggestive of a LRTI. This conclusion may be weakened by the risk of bias of the studies and the lack of complete data available.

Guidelines and quality measures: do they improve outcomes of patients with community-acquired pneumonia?

Community-acquired pneumonia (CAP) has a significant impact in terms of morbidity, mortality, and cost of care. Guidelines play an important role in the management of this disease, and evidence supporting the positive effects of guidelines on outcomes in patients with CAP is substantial. However, evidence supporting many of the CAP quality indicators is low, and pay-for-performance measures do not seem to influence clinically important outcomes. Future CAP quality indicators should incorporate evidence-based interventions.

Viral and bacterial aetiology of community-acquired pneumonia in adults

BACKGROUND

Modern molecular techniques reveal new information on the role of respiratory viruses in community-acquired pneumonia. In this study, we tried to determine the prevalence of respiratory viruses and bacteria in patients with community-acquired pneumonia who were admitted to the hospital.

METHODS

Between April 2008 and April 2009, 408 adult patients (aged between 20 and 94 years) with community-acquired pneumonia were tested for the presence of respiratory pathogens using bacterial cultures, real-time PCR for viruses and bacteria, urinary antigen testing for Legionella and Pneumococci and serology for the presence of viral and bacterial pathogens.

RESULTS

Pathogens were identified in 263 (64·5%) of the 408 patients. The most common single organisms in these 263 patients were Streptococcus pneumoniae (22·8%), Coxiella burnetii (6·8%) and influenza A virus (3·8%). Of the 263 patients detected with pathogens, 117 (44·5%) patients were positive for one or more viral pathogens. Of these 117 patients, 52 (44·4%) had no bacterial pathogen. Multiple virus infections (≥2) were found in 16 patients.

CONCLUSION

In conclusion, respiratory viruses are frequently found in patients with CAP and may therefore play an important role in the aetiology of this disease.

Elderly patients with community-acquired pneumonia: optimal treatment strategies

Community-acquired pneumonia (CAP) is a common infectious disease that still causes substantial morbidity and mortality. Elderly people are frequently affected, and several issues related to care of this condition in the elderly have to be considered. This article reviews current recommendations of guidelines with a special focus on aspects of the care of elderly patients with CAP. The most common pathogen in CAP is still Streptococcus pneumoniae, followed by other pathogens such as Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella species. Antimicrobial resistance is an increasing problem, especially with regard to macrolide-resistant S. pneumoniae and fluoroquinolone-resistant strains. With regard to β-lactam antibacterials, resistance by H. influenzae and Moraxella catarrhalis is important, as is the emergence of multidrug-resistant Staphylococcus aureus. The main management decisions should be guided by the severity of disease, which can be assessed by validated clinical risk scores such as CURB-65, a tool for measuring the severity of pneumonia based on assessment of confusion, serum urea, respiratory rate and blood pressure in patients aged ≥65 years. For the treatment of low-risk pneumonia, an aminopenicillin such as amoxicillin with or without a β-lactamase inhibitor is frequently recommended. Monotherapy with macrolides is also possible, although macrolide resistance is of concern. When predisposing factors for special pathogens are present, a β-lactam antibacterial combined with a β-lactamase inhibitor, or the combination of a β-lactam antibacterial, a β-lactamase inhibitor and a macrolide, may be warranted. If possible, patients who have undergone previous antibacterial therapy should receive drug classes not previously used. For hospitalized patients with non-severe pneumonia, a common recommendation is empirical antibacterial therapy with an aminopenicillin in combination with a β-lactamase inhibitor, or with fluoroquinolone monotherapy. With proven Legionella pneumonia, a combination of β-lactams with a fluoroquinolone or a macrolide is beneficial. In severe pneumonia, ureidopenicillins with β-lactamase inhibitors, broad-spectrum cephalosporins, macrolides and fluoroquinolones are used. A combination of a broad-spectrum β-lactam antibacterial (e.g. cefotaxime or ceftriaxone), piperacillin/tazobactam and a macrolide is mostly recommended. In patients with a predisposition for Pseudomonas aeruginosa, a combination of piperacillin/tazobactam, cefepime, imipenem or meropenem and levofloxacin or ciprofloxacin is frequently used. Treatment duration of more than 7 days is not generally recommended, except for proven infections with P. aeruginosa, for which 15 days of treatment appears to be appropriate. Further care issues in all hospitalized patients are timely administration of antibacterials, oxygen supply in case of hypoxaemia, and fluid management and dose adjustments according to kidney function. The management of elderly patients with CAP is a challenge. Shifts in antimicrobial resistance and the availability of new antibacterials will change future clinical practice. Studies investigating new methods to detect pathogens, determine the optimal antimicrobial regimen and clarify the duration of treatment may assist in further optimizing the management of elderly patients with CAP.

The impact of guidelines on the outcomes of community-acquired and ventilator-associated pneumonia

The correct implementation of the current guidelines for the management of community-acquired pneumonia is associated with less mortality, faster clinical stabilization, and lower costs in these patients. By contrast, implementing the current guidelines for the management of hospital-acquired pneumonia has been followed by an increase in initially adequate antibiotic treatment but has not been accompanied by a consistently improved outcome in patients.

Comparative antibiotic failure rates in the treatment of community-acquired pneumonia: Results from a claims analysis

INTRODUCTION

Antibiotic treatment failure contributes to the economic and humanistic burdens of community-acquired pneumonia (CAP) by increasing morbidity, mortality, and healthcare costs. This study compared treatment failure rates of levofloxacin with those of other antibiotics in a large US sample.

METHODS

Medical and pharmacy claims in the nationally representative SDI database were used to identify adults with a new outpatient diagnosis of CAP receiving a study antibiotic (levofloxacin, amoxicillin/clavulanate, azithromycin, moxifloxacin) between September 1, 2005 and March 31, 2008. Treatment failure was defined as ≥1 of the following events ≤30 days after index date: a refill for the index antibiotic after completed days of therapy, a different antibiotic dispensed >1 day after the index prescription, or hospitalization with a pneumonia diagnosis or emergency department visit >3 days postindex. Cohorts were propensity score matched for demographic and clinical characteristics. Treatment failure rates were compared between pairs of cohorts for the full sample and for high-risk patients (age ≥65 and/or on Medicaid).

RESULTS

Among the 3994 study patients, the numbers of dispensed index prescriptions were 268 for amoxicillin/clavulanate, 1609 for azithromycin, 1460 for levofloxacin, and 657 for moxifloxacin. Unadjusted treatment failure rates for the sample were 20.8% for levofloxacin, 23.9% for amoxicillin/clavulanate, 23.9% for azithromycin, and 19.9% for moxifloxacin. For high-risk patients, unadjusted treatment failure rates were 19.1% for levofloxacin, 26.1% for amoxicillin/clavulanate, 26.3% for azithromycin, and 24.3% for moxifloxacin. Propensity score-matched treatment failure rates were significantly lower with levofloxacin than azithromycin (19.8% vs. 24.5%, odds ratio [OR] comparator vs. levofloxacin 1.38; 95% CI: 1.14, 1.67), a difference amplified in high-risk patients (19.0% vs. 26.4%, OR 1.61; 95% CI: 1.22, 2.13). No significant differences were observed for other paired comparisons.

CONCLUSION

In a large US sample, treatment failure in CAP appeared to be less likely with quinolones (such as levofloxacin) than azithromycin, an effect particularly marked in high-risk patients (age ≥65 and/or on Medicaid).