Sparfloxacin vs ofloxacin in the treatment of acute bacterial exacerbations of chronic bronchitis: a multicenter, double-blind, randomized, comparative study. Sparfloxacin Multicenter ABECB Study Group

Adverse events of fluoroquinolones vs. other antimicrobials prescribed in primary care: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Fluoroquinolones (FQs) are second-line antimicrobial agents. Once the decision to prescribe an antimicrobial is made, the choice of antimicrobial should be based on both the benefits and adverse effects. This systematic review quantifies the occurrence of common adverse events (AEs) related to FQs in relation to any other antimicrobial for any indication in primary care.

METHODS

We searched randomized controlled trials from Embase, PubMed, Cochrane Central Register of Controlled Trials and CINHAL. FQs had to be administered orally, for any indication, to adults and in primary care. Data were extracted independently in standard forms in "Covidence". Pooled estimates of the intervention effects for AEs were determined by the Peto odds ratios (ORs) and 95% confidence intervals (CIs) in Revman.

RESULTS

In the 39 studies selected, the most commonly reported AEs were nausea, vomiting, diarrhoea, headache, dizziness, and rash. A meta-analysis of 28 studies reporting AEs showed central nervous system (CNS)-related AEs (OR 1.40 (1.12-1.75) P = 0.003, heterogeneity (I²) = 0%) and gastrointestinal (GI)-related AEs (OR 1.20 (1.06-1.36) P = 0.005, I² = 80%) were significantly associated with FQs compared with other antimicrobials. Compared with FQs, co-amoxiclav showed significantly more total AEs (OR 0.70 (0.54-0.90) P = 0.006, I² = 78%) and GI-related AEs (OR 0.69 (0.52-0.91) P = 0.008, I² = 94%). Withdrawal or discontinuation due to drug-related AEs was higher for FQs (OR 1.19 (1.00-1.42) P = 0.05, I² = 5%). Sensitivity analyses did not change these results.

CONCLUSION

FQs are associated with more CNS- and GI-related AEs compared with other types of antimicrobial. This information is relevant to support decision making in relation to antimicrobial prescribing.

Review: Do we need new antibiotics for treating exacerbations of COPD?

Exacerbations may produce permanent impairment in lung function and health status in patients with COPD. Up to 70% of episodes have a bacterial etiology, being of mixed viral infection in some cases. The new, more active antibiotics have demonstrated better eradication of bacteria in the airways and, consequently, prolongation of the time to the next exacerbation. However, the ability of bacteria to develop resistance to the antibiotics currently used warrants novel research into new families of antimicrobials, and the adoption of new strategies such as the prevention of exacerbations, nebulized antibiotic treatment or the use of antibiotics in combination.

Pseudomonal Infections in Patients with COPD

COPD is a common disease with increasing prevalence. The chronic course of the disease is characterized by acute exacerbations that cause significant worsening of symptoms. Bacterial infections play a dominant role in approximately half of the episodes of acute exacerbations of COPD. The importance of pseudomonal infection in patients with acute exacerbations of COPD stems from its relatively high prevalence in specific subgroups of these patients, and particularly its unique therapeutic ramifications. The colonization rate of Pseudomonas aeruginosa in patients with COPD in a stable condition is low.A review of a large number of clinical series of unselected outpatients with acute exacerbations of COPD revealed that P. aeruginosa was isolated from the patients' sputum at an average rate of 4%. This rate increased significantly in COPD patients with advanced airflow obstruction, in whom the rate of sputum isolates of P. aeruginosa reached 8-13% of all episodes of acute exacerbations of COPD. However, the great majority of bacteria isolated in these patients were not P. aeruginosa, but the three classic bacteria Streptococcus pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis. The subgroup of patients, with acute exacerbations of COPD, with the highest rate of P. aeruginosa infection, which approaches 18% of the episodes, is mechanically ventilated patients. However, even in this subgroup the great majority of bacteria isolated are the above-mentioned three classic pathogens. In light of these epidemiologic data and other important considerations, and in order to achieve optimal antibacterial coverage for the common infectious etiologies, empiric antibacterial therapy should be instituted as follows. Patients with acute exacerbations of COPD with advanced airflow obstruction (FEV(1) <50% of predicted under stable conditions) should receive once daily oral therapy with one of the newer fluoroquinolones, i.e. levofloxacin, moxifloxacin, gatifloxacin, or gemifloxacin for 5-10 days. Patients with severe acute exacerbations of COPD who are receiving mechanical ventilation should receive amikacin in addition to one of the intravenous preparations of the newer fluoroquinolones or monotherapy with cefepime, a carbapenem or piperacillin/tazobactam. In both subgroups it is recommended that sputum cultures be performed before initiation of therapy so that the results can guide further therapy.

Magnitude of QT prolongation associated with a higher risk of Torsades de Pointes

PURPOSE

Drug induced Torsades de Pointes (TdP) is a major concern for new drugs seeking regulatory approval. Prolongation of QT intervals greater than 60 millisecond or to longer than 500 millisecond in an individual patient has been considered to be associated with a higher risk. The purpose of this study is to identify values inferred from a population that predict a stronger potential for TdP.

METHODS

Prolongation data of 30 non-antiarrhythmic QT prolonging drugs were analysed. Depending on how strong the drugs were associated with TdP, they were categorized as strong or borderline torsadogens. The differences in mean QTc increases between the two groups were compared and cut-off values that distinguished strong from borderline drugs were searched for.

RESULTS

The average QTc increase of 19.3 millisecond of strong torsadogens was significantly greater than the 8.0 millisecond of borderline torsadogens. Prolongation greater than 12 millisecond in the context of monotherapy or 25 millisecond in the presence of metabolic inhibition and an upper bound of 95% confidence interval (CI) for the mean QTc increase greater than 14 millisecond in monotherapy or 30.1 millisecond in combination therapy with metabolic inhibitors favoured a stronger association with TdP.

CONCLUSIONS

Drugs strongly associated with TdP have greater QTc increases than those with less concern. Several cut-off values have been noted to distinguish between them. These values may be helpful for evaluation of TdP risk for future QT prolonging drugs.

The role of quinolones in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is a disease state characterized by the presence of airflow obstruction due to chronic bronchitis and/or emphysema. The airflow obstruction is generally progressive. In the past asthma was often confused with chronic obstructive pulmonary disease but as the cellular inflammatory mechanisms are quite different to chronic bronchitis and emphysema it is prudent to separate this condition of airway hyper-responsiveness. Exacerbation of chronic obstructive pulmonary disease is a considerable burden on health service resources in terms of morbidity and mortality. Approximately one half of exacerbations can be attributed to bacterial pathogens, the major pathogens being Haemophilus influenzae, Streptococcus pnemoniae and Moraxella catarrhalis. Resistance to common first-line treatment antibiotics such as the beta-lactams can be variable. Newer fluoroquinolones such as grepafloxacin, levofloxacin, sparfloxacin, clinafloxacin, moxifloxacin, gatifloxacin and gemifloxacin are characterized by improved activity against Gram positive bacteria as well as their Gram negative properties. However, more randomized controlled trials need to be accomplished before the true role of quinolones in exacerbation of chronic obstructive pulmonary disease is clearly ascertained.

Role of infection and antimicrobial therapy in acute exacerbations of chronic obstructive pulmonary disease

Over the past several years, the significance of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in patients with chronic airflow obstruction has become increasingly apparent due to the impact these episodes have on the natural history of disease. It is now known that frequent AECOPD can adversely affect a patient's health-related quality of life and short- and long-term pulmonary function. The economic burden of these episodes is also substantial. AECOPDs represent a local and systemic inflammatory response to both infectious and noninfectious stimuli, but the majority of episodes are likely related to bacterial or viral pathogens. Patients with purulent sputum and multiple symptoms are the most likely to benefit from treatment with antibiotics. Antibiotic choice should be tailored to the individual patient, taking into account the severity of the episode and host factors which might increase the likelihood of treatment failure. Current evidence suggests that therapeutic goals not only include resolution of the acute episode, but also prolonging the time to the next event. In the future, preventing exacerbations will likely become increasingly accepted as an additional therapeutic goal in chronic obstructive pulmonary disease patients.

[Second consensus report on the use of antimicrobial agents in exacerbations of chronic obstructive pulmonary disease]

Aware of the importance of chronic obstructive pulmonary disease (COPD), a panel of experts belonging to the Spanish Society of Respiratory Medicine and Thoracic Surgery (SEPAR), the Spanish Society of Chemotherapy (SEQ) and the Spanish Society of Family and Community Medicine (SEMFyC) issued a statement of consensus in 2000 to serve as the basis for adequate antibiotic control of the disease. Three years later, in accordance with significant scientific progress made in this area, the statement has been thoroughly revised. The new paper in fact constitutes a second consensus statement on the use of antibiotics in COPD exacerbations. When several scientific associations expressed interest in joining the project and contributing to it the Spanish Society of Emergency Medicine (SEMES), the Spanish Society of General Medicine (SEMG) and the Spanish Society of Rural and General Medicine (SEMERGEN) their incorporation led SEPAR and SEMFyC to change the structure of the statement and certain aspects of its content. Additionally, a new group of antibiotics, the ketolides, has joined the therapeutic arsenal. Telithromycin, the single representative of the group for the moment, can be considered not only an alternative treatment but even the drug of choice in certain clinical settings that are analyzed in the new statement. Those developments, along with others, such as the increasingly recognized action of levofloxacin against Pseudomonas aeruginosa and the steady action of amoxicillin with clavulanic acid when administered at recommended doses every 8 hours, provide new antimicrobial therapeutic protocols for COPD. Finally, the statement includes a scientific analysis of other groups of antimicrobial agents (macrolides, oral cephalosporins, etc.) and guidelines for both primary care physicians and specialists to follow when prescribing them.

Randomised double-blind comparison of oral gatifloxacin and co-amoxiclav for acute exacerbation of chronic Bronchitis

Antimicrobial therapy can have a significant impact in the treatment of acute infectious exacerbations in patients with chronic bronchitis, in whom repeated episodes are common. The aim of this randomised, double-blind, double-dummy, parallel group study was to compare the efficacy and safety of oral gatifloxacin (200 and 400 mg once daily) administered for 5 days with co-amoxiclav (500 mg amoxicillin/125 mg clavulanic acid t.i.d.) administered for 10 days in 414 adult patients with acute exacerbation of chronic bronchitis. Overall clinical response rates (cure plus improvement) were 86.2%, 79.4% and 81.7% in the gatifloxacin 200 mg, gatifloxacin 400 mg and co-amoxiclav groups, respectively, and the equivalence hypothesis used for statistical analysis showed equivalent efficacy for both gatifloxacin 200 and 400 mg compared to co-amoxiclav. The same was true for rates of bacterial response, with eradication or presumed eradication of causative pathogens achieved in 87.5%, 87.3% and 79.1% of cases in the gatifloxacin 200 mg, gatifloxacin 400 mg and co-amoxiclav groups, respectively. All treatments were well tolerated, with the nature and frequency of treatment-related adverse events similar in all groups. The results of the study show that gatifloxacin is a safe and effective agent for the treatment of patients with chronic bronchitis experiencing an acute infectious exacerbation.

Telithromycin is as effective as amoxicillin/clavulanate in acute exacerbations of chronic bronchitis

This randomized, double-blind study evaluated the efficacy and safety of a short, 5-day course of telithromycin, a new ketolide antibacterial, compared with a standard 10-day course of amoxicillin/clavulanate, in the treatment of acute exacerbations of chronic bronchitis (AECB). The study enrolled 325 adult patients with AECB and a history of chronic obstructive pulmonary disease (COPD). Patients received either telithromycin 800 mg once daily (qd) for 5 days (followed by placebo for 5 days) or amoxicillin/clavulanate 500/125 mg three times daily (tid) for 10 days. Clinical cure rates for telithromycin post-therapy (Days 17-21, test-of-cure) and late post-therapy (Days 31-36) were 86.1 and 78.1%, respectively; 82.1 and 75.0% for amoxicillin/clavulanate. Excellent clinical cure rates were also observed for high-risk patients. Bacteriologic outcome was satisfactory for 69.2% of telithromycin recipients vs 70.0% for amoxicillin/clavulanate recipients. Both treatments were generally well tolerated, although the frequency of drug-related adverse events was almost two-fold higher for amoxicillin/clavulanate (25.0 vs. 13.1%). Thus, a 5-day course of telithromycin 800 mg qd is an effective and well-tolerated alternative to a standard 10-day course of amoxicillin/clavulanate 500/125 mg tid for first-line empiric treatment of AECB in adults with COPD.

Fluoroquinolones for the treatment of outpatient community-acquired pneumonia

The increasing prevalence of beta-lactam and macrolide resistance in bacteria that cause respiratory infections has underscored the need for effective antimicrobial agents. The broad spectrum, excellent oral bioavailability, and once-daily dosing of fluoroquinolones contributed to the introduction of several new agents in the past decade. This class is among the world's most used antimicrobial therapies in community and hospital settings. Fluoroquinolones are generally well tolerated, but safety profiles differ widely among agents. Knowledge of in vitro activity, local microbiologic susceptibility and resistance patterns, adverse effects, and potential drug interactions should influence the selection of the best agent for individual patients. This overview of the fluoroquinolones directs particular attention to use in community-acquired pneumonia and safety.

Optimisation of antimicrobial therapy using pharmacokinetic and pharmacodynamic parameters

To understand the relationship between drug dose and efficacy, pharmacokinetic (PK) and pharmacodynamic (PD) characteristics need to be integrated. Patterns of antimicrobial activity fall into one of two major patterns: time-dependent killing and concentration-dependent killing. Time-dependent killing is characteristic of many antibiotic classes, such as beta-lactams and macrolides, and seeks to optimise the duration of exposure of a pathogen to an antimicrobial. The major PK/PD parameter correlating with efficacy of time-dependent antimicrobials is the serum concentration present for 40-50% of the dosing interval, and this concentration is the susceptibility limit or breakpoint for the dosing regimen used. The second pattern, concentration-dependent killing, seeks to maximise antimicrobial concentration and is seen with aminoglycosides, quinolones and azalides. The major PK/PD parameter correlating with efficacy of these agents is the 24-h area under the curve to MIC ratio, which should be > or =25 for less severe infections or in immunocompetent hosts, and > or =100 in more severe infections or in immunocompromised hosts. PK/PD breakpoints for concentration-dependent agents can therefore be calculated from the formula AUC divided by 25. This enables development of PK/PD breakpoints based on the above parameters for time- and concentration-dependent agents for defined dosing regimens. For an antimicrobial to be useful empirically, the MIC90s of the agent against the common pathogens responsible for the disease being treated should be below the PK/PD breakpoint. This is particularly important for oral dosing regimens for treating emerging resistant respiratory tract pathogens, where efficacy against the predominant pathogens, Streptococcus pneumoniae and Haemophilus influenzae, is required.

Fluoroquinolone adverse effects and drug interactions

Extensive pharmacologic and clinical development of quinolone antimicrobial agents has resulted in improved antimicrobial activity, pharmacokinetic features, toxicity, and drug-drug interaction profiles. Nalidixic acid and other early quinolones had limited use due to poor pharmacokinetics, relatively narrow antimicrobial spectrum of activity, and frequent adverse effects. Beginning with the development of fluoroquinolones, such as norfloxacin and ciprofloxacin, in the 1980s, the agents assumed a greatly expanded clinical role because of their broad antimicrobial spectrum of action, improved pharmacokinetic properties, and more acceptable safety profile. Although the pharmacokinetics and efficacy of the drugs have improved significantly, a major area of continued emphasis is to further reduce the frequency and severity of adverse events and drug-drug interactions. Older agents such as ciprofloxacin and ofloxacin are still extensively prescribed, but the focus of this article is on the newer fluoroquinolones (levofloxacin and other drugs that have been approved or have been under investigation since approximately 1997).

Selection of clinical, patient-reported, and economic end points in acute exacerbation of chronic bronchitis

BACKGROUND

Acute exacerbation of chronic bronchitis (AECB) places tremendous burden on patients, providers, employers, and health care systems.

OBJECTIVE

The purpose of this paper is to (1) review the clinical, patient-reported, and economic measures used to evaluate disease burden and treatment effectiveness in AECB in clinical trials and (2) propose a guide for selecting study end points in AECB that will help capture all the relevant disease outcomes.

METHODS

Two literature searches of the PubMed database were conducted to identify studies of clinical trials in bronchitis and evaluate the clinical, patient-reported, and economic end points used in these studies.

RESULTS

Previous studies have focused primarily on clinician-assessed outcomes, which do not capture the full impact of AECB on patients' lives. Reporting mechanisms for most end points have been inconsistent, limiting the ability to compare information or interpret differences. Previous studies have given limited attention to patient-reported outcomes and the economic implications of AECB. Patient-reported outcomes such as speed of symptom relief and work productivity are important parameters for assessing treatment effectiveness and provide practical information for treatment evaluation.

CONCLUSIONS

Additional research is needed to develop, examine, and validate patient-reported outcomes and the indirect costs of AECB. Measuring the relevant clinical, economic, and patient-reported outcomes in AECB patients using standardized methods may lead to a clearer understanding of the disease burden and the role, effectiveness, and cost-effectiveness of antibiotic treatment.

Is more than one quinolone needed in clinical practice?

OBJECTIVE

To review clinical information on fluoroquinolone antimicrobials to distinguish between these agents and help define their place in clinical practice.

DATA SOURCES

Primary and review articles on fluoroquinolones available commercially in the US as of August 2000 were identified through MEDLINE (from 1993-August 2000) and secondary sources.

STUDY SELECTION AND DATA EXTRACTION

All pertinent, published, clinical trials for levofloxacin, moxifloxacin, and gatifloxacin were included. Minimal data were included for quinolones with restricted or limited uses, including trovafloxacin, sparfloxacin, enoxacin, and lomefloxacin. Due to the quantity of data on ciprofloxacin, only more recent or pivotal trials or articles summarizing data on specific infections were included. Relevant information was included if it was believed to assist in differentiating between the fluoroquinolones for infections for which these agents would most commonly be considered.

DATA SYNTHESIS

Fluoroquinolones are a potent class of intravenous and oral broad-spectrum antimicrobial agents used for treating a wide range of community-acquired and nosocomial infections. More than 10 quinolones have been approved for use; although some of these have been withdrawn from the market, numerous others are under investigation. It has become increasingly important to be able to differentiate between these agents.

CONCLUSIONS

Differences in safety, antimicrobial spectrum of activity, and resistance development support the selective use of various fluoroquinolones in differing clinical situations.

Acute exacerbations of chronic bronchitis: what role for the new fluoroquinolones?

Acute exacerbations of chronic bronchitis (AECB) are a major cause of morbidity and mortality. Bacterial pathogens are implicated in about half the episodes of AECB. Empirical antibacterials have a significant benefit in AECB; however, several recent developments have considerably complicated antibacterial choice for this condition. New fluoroquinolone antibacterials introduced in the last decade are theoretically well suited for the treatment of AECB, as the in vitro antimicrobial spectrum of these drugs includes all the major pathogens involved. The pharmacokinetic and pharmacodynamic properties of the new fluoroquinolones are superior to many other antibacterials used to treat AECB. In trials, clinical success with the new fluoroquinolones was equivalent and bacteriological success was occasionally superior to nonfluoroquinolone comparators. However, these clinical trials did not assess several potentially important end-points for which the theoretical superiority of the fluoroquinolones may translate into differences in outcome. Rare but serious adverse effects with some of the new fluoroquinolones have shaken the confidence of prescribing physicians in this class of drugs. Emergence of the resistance of Streptococcus pneumoniae to fluoroquinolones has raised concerns about indiscriminate and widespread use of the new agents for trivial infections. Patients with AECB are a heterogeneous population who should be stratified in order to appropriately choose empirical antibacterial therapy. Highly efficacious antibacterial therapy, such as the new fluoroquinolones, is appropriate as a first-line choice for patients who have risk factors for a poor outcome or are in intensive care units. Such selected use of the new fluoroquinolones balances individual benefit with societal concerns of the use of these agents for AECB.

Factors associated with relapse after ambulatory treatment of acute exacerbations of chronic bronchitis. DAFNE Study Group

This study aimed to identify the risk factors for relapse after ambulatory treatment of acute exacerbations of chronic bronchitis (AECB) that can easily be used in a primary care setting. Data were prospectively collected on 2,414 ambulatory patients with AECB from 268 general practices located throughout Spain. A multivariate model to identify risk factors independently associated with failures was developed and validated from the information recorded at the inclusion visit and at 30-days follow-up visit. A total of 507 patients relapsed (21%); of these, 84 required admission (16.5%). The multivariate model for prediction of the risk of relapse included 2,414 cases: 1,689 for the developmental sample and 725 in the validation sample. The model obtained contained three readily-obtainable variables: ischaemic heart disease (odds ratio (OR)=1.63; 95% confidence interval (CI)=1.07-2.47), degree of dyspnoea (OR = 1.31; 1.14-1.50) and number of visits to the general practitioner the previous year (OR = 1.07; 1.04-1.10). The model calibrated well in developmental and validation samples (goodness-of-fit tests: p = 0.295 and p = 0.637, respectively). Severity of the exacerbation was not associated with increased risk of relapse in either univariate or multivariate analysis. The present results suggest that baseline characteristics of the patients such as degree of dyspnoea, coexisting ischaemic heart disease and number of previous visits to the general practitioner for respiratory problems are strongly associated with increased risk of relapse after ambulatory treatment of acute exacerbations of chronic bronchitis. In contrast, exacerbation severity was not associated with clinical failure. Guidelines for management of acute exacerbations of chronic bronchitis should consider such risk factors and advocate intensive broad spectrum treatment and closer follow-up of patients exhibiting them.

Bacterial infection in chronic obstructive pulmonary disease in 2000: a state-of-the-art review

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States. The precise role of bacterial infection in the course and pathogenesis of COPD has been a source of controversy for decades. Chronic bacterial colonization of the lower airways contributes to airway inflammation; more research is needed to test the hypothesis that this bacterial colonization accelerates the progressive decline in lung function seen in COPD (the vicious circle hypothesis). The course of COPD is characterized by intermittent exacerbations of the disease. Studies of samples obtained by bronchoscopy with the protected specimen brush, analysis of the human immune response with appropriate immunoassays, and antibiotic trials reveal that approximately half of exacerbations are caused by bacteria. Nontypeable Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae are the most common causes of exacerbations, while Chlamydia pneumoniae causes a small proportion. The role of Haemophilus parainfluenzae and gram-negative bacilli remains to be established. Recent progress in studies of the molecular mechanisms of pathogenesis of infection in the human respiratory tract and in vaccine development guided by such studies promises to lead to novel ways to treat and prevent bacterial infections in COPD.

Risk factors for acquisition of levofloxacin-resistant Streptococcus pneumoniae: a case-control study

A case-control study was conducted to identify the risk factors associated with levofloxacin-resistant Streptococcus pneumoniae (LRSP) colonization or infection. Twenty-seven case patients (patients with LRSP) were compared with 54 controls (patients with levofloxacin-susceptible S. pneumoniae). Risk factors that were significantly associated with LRSP colonization or infection, according to univariate analysis, included an older age (median age, 75 years for case patients versus 72.5 years for controls), residence in a nursing home (odds ratio [OR], 7.2), history of recent (OR, 4.6) and multiple (OR, 4.4) hospitalizations, prior exposure to fluoroquinolones (OR, 10.6) and beta-lactams (OR, 8.6), presence of chronic obstructive pulmonary disease (COPD; OR, 5.9), and nosocomial origin of the bacteria (OR, 5.7). Multivariate analysis showed that presence of COPD (OR, 10.3), nosocomial origin of the bacteria (OR, 16.2), residence in a nursing home (OR, 7.4), and exposure to fluoroquinolones (OR, 10.7) were independently associated with LRSP colonization or infection. Thus, a distinct group of patients with COPD is the reservoir of LRSP.

The new antibiotics

It is easy to become overwhelmed by the amount of information available on the new antibiotics and difficult to keep abreast of the appropriate indications for each of them. For most patients with community-acquired infections, the first-line agent is usually not one of the newer agents, but a standard regimen, or at times, no antibiotic at all. The development of resistance is likely to parallel the extent to which these agents are prescribed. They should be used only when standard treatment fails, when compliance with treatment is a real and serious issue, or when the patient has a real allergic reaction to the standard regimen.

Microbiologic efficacy of moxifloxacin for the treatment of community-acquired pneumonia due to Chlamydia pneumoniae

Nasopharyngeal specimens for culture of Chlamydia pneumoniae were obtained from patients participating in two pneumonia treatment studies: an open study of 400 mg moxifloxacin orally, qds for 10 days and a randomized, double-blind comparison of moxifloxacin, 400 mg orally, qds versus clarithromycin, 500 mg orally, bd, both for 10 days. C. pneumoniae was eradicated from the nasopharynx of seven of ten (70%) microbiologically evaluable patients who were treated with moxifloxacin and four of four who were treated with clarithromycin. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of 21 isolates of C. pneumoniae from 18 patients obtained before and after therapy were performed against moxifloxacin and clarithromycin. The MIC(90)s and MBC(90)s for moxifloxacin and clarithromycin were 1 and 0.06 mg/l, respectively. The MICs and MBCs against moxifloxacin of six isolates from three persistently infected patients who were treated with the drug were the same at baseline and follow-up. The persistence of C. pneumoniae after treatment with moxifloxacin was probably not due to the emergence of resistance.

Do bacteria cause exacerbations of COPD?

Exacerbations of COPD, which include combinations of dyspnea, cough, wheezing, increased sputum production (and a change in its color to green or yellow), are common. The role of bacterial infection in causing these episodes and the value of antibiotic therapy for them are debated. An assessment of the microbiological studies indicates that conventional bacterial respiratory pathogens, such as Streptococcus pneumoniae and Haemophilus influenzae, are absent in about 50% of attacks. The frequency of isolating these organisms, which often colonize the bronchi of patients in stable condition, does not seem to increase during exacerbations, and their density typically remains unchanged. Serologic studies generally fail to show rises in antibody titers to H influenzae; the only report available demonstrates none to Haemophilus parainfluenzae; and the sole investigation of S pneumoniae is inconclusive. Trials with vaccines against S pneumoniae and H influenzae show no clear benefit in reducing exacerbations. The histologic findings of bronchial biopsies and cytologic studies of sputum show predominantly increased eosinophils, rather than neutrophils, contrary to what is expected with bacterial infections. The randomized, placebo-controlled trials generally show no benefit for antibiotics, but most have studied few patients. A meta-analysis of these demonstrated no clinically significant advantage to antimicrobial therapy. The largest trials suggest that antibiotics confer no advantage for mild episodes; with more severe attacks, in which patients should receive systemic corticosteroids, the addition of antimicrobial therapy is probably not helpful.

Relationship of sputum color to nature and outpatient management of acute exacerbations of COPD

STUDY OBJECTIVES

To stratify COPD patients presenting with an acute exacerbation on the basis of sputum color and to relate this to the isolation and viable numbers of bacteria recovered on culture.

DESIGN

Open, longitudinal study of sputum characteristics and acute-phase proteins.

SETTING

Patients presenting to primary-care physicians in the United Kingdom. Patients were followed up as outpatients in specialist clinic.

PATIENTS

One hundred twenty-one patients with acute exacerbations of COPD were assessed together with a single sputum sample on the day of presentation (89 of whom produced a satisfactory sputum sample for analysis). One hundred nine patients were assessed 2 months later when they had returned to their stable clinical state.

INTERVENTIONS

The expectoration of green, purulent sputum was taken as the primary indication for antibiotic therapy, whereas white or clear sputum was not considered representative of a bacterial episode and the need for antibiotic therapy.

RESULTS

A positive bacterial culture was obtained from 84% of patients sputum if it was purulent on presentation compared with only 38% if it was mucoid (p < 0.0001). When restudied in the stable clinical state, the incidence of a positive bacterial culture was similar for both groups (38% and 41%, respectively). C-reactive protein concentrations were significantly raised (p < 0.0001) if the sputum was purulent (median, 4.5 mg/L; interquartile range [IQR], 6. 2 to 35.8). In the stable clinical state, sputum color improved significantly in the group who presented with purulent sputum from a median color number of 4.0 (IQR, 4.0 to 5.0) to 3.0 (IQR, 2.0 to 4. 0; p < 0.0001), and this was associated with a fall in median C-reactive protein level to 2.7 mg/L (IQR, 1.0 to 6.6; p < 0.0001).

CONCLUSIONS

The presence of green (purulent) sputum was 94.4% sensitive and 77.0% specific for the yield of a high bacterial load and indicates a clear subset of patient episodes identified at presentation that is likely to benefit most from antibiotic therapy. All patients who produced white (mucoid) sputum during the acute exacerbation improved without antibiotic therapy, and sputum characteristics remained the same even when the patients had returned to their stable clinical state.

Sparfloxacin: a review

BACKGROUND

The continuing increase in the rate of penicillin and cephalosporin resistance among respiratory pathogens and of cross-resistance to macrolide antibiotics has led to the recommendation that fluoroquinolone antibiotics be used to treat high-risk patients with community-acquired pneumonia (CAP) and acute bacterial exacerbations of chronic bronchitis (ABECB).

OBJECTIVE

This review focuses on sparfloxacin, an oral fluoroquinolone, discussing its mechanism of action, activity, pharmacokinetic characteristics, safety, and efficacy in CAP and ABECB.

METHODS

Studies were identified by a MEDLINE search of the literature from 1990 to 1999, supplemented by educational materials from conferences and symposia.

RESULTS

Sparfloxacin is active against the major respiratory pathogens and against the atypical pathogens in pneumonia that are being reported with increasing frequency. Its long half-life permits once-daily dosing. In large trials in CAP and ABECB in which all isolates were susceptible to both comparators, sparfloxacin was found to have similar efficacy to erythromycin, cefaclor, amoxicillin, ofloxacin, and clarithromycin. Its safety profile is similar to that of the macrolides and other quinolone antimicrobial agents. Photosensitivity, nausea, and diarrhea are the most common adverse events reported in clinical trials of sparfloxacin. Its use is contraindicated in patients with QTc-interval prolongation.

CONCLUSION

The increasing prevalence of beta-lactam- and macrolide-resistant bacteria in respiratory infections emphasizes the need for newer agents such as the fluoroquinolones. The choice between agents should be based on activity against the relevant respiratory pathogens in high-risk patients.

Clinical efficacy and antimicrobial pharmacodynamics

Changes in the susceptibility of bacterial pathogens and the availability of new antimicrobial drugs mean that physicians need to understand the underlying pharmacodynamics of each antimicrobial therapy. Antimicrobial pharmacodynamics determine clinical efficacy and should therefore be carefully considered when selecting appropriate antibiotic agents in the therapeutic setting.

Short-course moxifloxacin therapy for treatment of acute bacterial exacerbations of chronic bronchitis. The Bronchitis Study Group

Chronic bronchitis is common among adults and infectious exacerbations contribute considerably to morbidity and mortality. We aimed to compare the safety and efficacy of moxifloxacin to clarithromycin for the treatment of patients with acute bacterial exacerbations of chronic bronchitis (ABECB) using a prospective, randomized, double-blind, parallel group trial. Between November 21, 1996 and April 7, 1998, 936 patients with acute exacerbations of chronic bronchitis (AECB) were enrolled at 56 centers across the United States of which 491 (52%) had ABECB (i.e. pretherapy pathogen). Patients were randomized to either oral moxifloxacin 400 mg administer once daily, for either 5 or 10 days, or clarithromycin 500 mg bid for 10 days. For the purpose of study blinding, the patients taking moxifloxacin received placebo to maintain uniform dosing. The main outcome measures were bacteriological response at the end of therapy (post-therapy days 0-6) and follow-up (7-17 days post-therapy) visits, as well as overall clinical response, clinical response at the end of therapy and clinical response at follow-up. Two patient populations were analyzed: efficacy-valid (i.e., those with a pretherapy pathogen) and intent-to-treat (i.e., all subjects that took drug). In 420 efficacy valid patients with a pretherapy organism, overall clinical resolution was 89% for 5 days moxifloxacin vs. 91% for 10 day moxifloxacin vs. 91% for 10 day clarithromycin. Bacteriological eradication rates at the end of therapy were 94% and 95% for 5-day moxifloxacin and 10-day moxifloxacin, respectively, and 91% for the clarithromycin group. Eradication rates at follow-up were 89% and 91% for 5-day moxifloxacin and 10-day moxifloxacin respectively, and 85% for the clarithromycin group. Among 926 intent-to-treat patients (312 5-day moxifloxacin, 302 10-day moxifloxacin and 312 clarithromycin), drug-related events were reported for 26%, 30% and 35%, respectively. Moxifloxacin 400 mg once daily, as a 5 or 10 day regimen, was found to be clinically and bacteriologically equivalent to 10 day clarithromycin for the treatment of ABECB. Given its favorable safety and tolerability profile, moxifloxacin administered once daily for 5 days may be as effective and a more convenient treatment than a standard course of clarithromycin for patients with ABECB.

Activity of quinolones against Chlamydia pneumoniae

Quinolones are currently being used as empirical therapy for the treatment of community-acquired pneumonia and other respiratory infections as they cover a broad range of conventional bacterial and 'atypical' pathogens, including Chlamydia pneumoniae. C. pneumoniae has been associated with 10 to 20% of community-acquired pneumonia in adults and recently has been implicated as being associated with several nonrespiratory conditions, including atherosclerosis. However, data on the treatment of even respiratory infection due to C. pneumoniae are limited. Although currently available quinolones have good activity against C. pneumoniae in vitro, all published treatment studies have relied on serological diagnosis, thus microbiological efficacy has not been assessed. Anecdotal experience suggests that in vitro activity may not always correlate with efficacy in vivo.

Chlamydia pneumoniae, asthma, and COPD: what is the evidence?

LEARNING OBJECTIVES

Reading this article will familiarize the reader with (1) the unique chlamydial intracellular life cycle and the propensity for human chlamydial infections to become persistent and to result in immunopathologic (inflammatory) damage in target organs and (2) current evidence linking Chlamydia pneumoniae (Cpn) infection to obstructive lung diseases (asthma and chronic obstructive pulmonary disease, COPD). Potential therapeutic implications of the Cpn-asthma association are also discussed.

DATA SOURCES

All Medline articles (January 1985 to March 1999) that cross-referenced the exploded MESH headings "lung diseases, obstructive" and "Chlamydia pneumoniae" (N = 76). Additional referenced articles, published abstracts, book chapters, and conference proceedings were also utilized.

STUDY SELECTION

(1) Case reports and case series that identified Cpn infection in asthma and/or COPD and (2) epidemiologic studies of markers for Cpn infection in asthma and/or COPD that included one or more control groups.

RESULTS

Of 18 controlled epidemiologic studies (over 4000 cases/controls), 15 found significant associations between Cpn infection and asthma using organism detection (polymerase chain reaction (PCR) testing (n = 2 studies) or fluorescent antigen testing (n = 1)), Cpn-specific secretory IgA (sIgA) antibody testing (n = 1), and/or specific serum IgE (n = 2), IgA (n = 4), IgG (n = 3) or other antibody criteria (n = 7). Eight case reports and 13 case series of Cpn infection in asthma (over 100 patients) also include descriptions of improvement or complete disappearance of asthma symptoms after prolonged antibiotic therapy directed against Cpn. Significant associations with COPD (over 1000 cases/controls) were reported in 5 of 6 studies. Results of treating chronic chlamydial infections in COPD patients have not been reported.

CONCLUSIONS

Although the full clinical significance of these Cpn-obstructive lung disease associations remains to be established, reports of asthma improvement after treatment of Cpn infection deserve further investigation. Clinicians who manage asthma should be aware of this information since it may help to manage difficult cases. The hypothesis that Cpn infection in COPD can amplify smoking-associated inflammation and worsen fixed obstruction also deserves further study.

Potential interactions of the extended-spectrum fluoroquinolones with the CNS

The new generation fluoroquinolones -- sparfloxacin, levofloxacin, grepafloxacin and trovafloxacin -- have been designed to respond to the clinical need for extended antimicrobial cover in the face of increasing global microbial resistance. Their main focus is in the treatment of respiratory infections, particularly those acquired in the community. CNS adverse effects, such as dizziness and headache, are known to occur relatively commonly with some fluoroquinolones and are not, in general, well tolerated by patients. The structural component of the fluoroquinolone molecule believed to be responsible for improved gram-positive activity is also believed to be implicated in the production of CNS adverse effects, including those arising from drug interactions with theophylline and NSAIDs. Inhibition of brain gamma-aminobutyric acid (GABA) receptor binding appears to be a strong indicator of CNS activity, though N-methyl-D-aspartate receptor binding has also been implicated. In accordance with the results of these predictive studies, clinical trials have found sparfloxacin, levofloxacin and grepafloxacin to be associated with a low incidence of CNS events. Trovafloxacin has been found to be associated with a higher incidence of CNS events (particularly lightheadedness and dizziness) than the other 3 agents. Ongoing and future clinical studies will help to define the usefulness of the predictive models, as well as reveal the full CNS adverse event profile of these and other investigational fluoroquinolones.

Activity of grepafloxacin and other fluoroquinones and newer macrolides against recent clinical isolates of Chlamydia pneumoniae

Chlamydia pneumoniae is a frequent cause of community-acquired respiratory tract infection including pneumonia and bronchitis. Quinolones have attracted interest as potential therapy for community-acquired respiratory tract infections because they are active against a wide range of pathogens including C. pneumoniae and Mycoplasma pneumoniae. The in vitro susceptibilities of C. pneumoniae were determined for grepafloxacin, levofloxacin, moxifloxacin, trovafloxacin, clarithromycin and azithromycin. Isolates of C. pneumoniae tested included two reference strains, TW-183 and CM-1, and 12 recent clinical isolates from adults with community-acquired pneumonia. Susceptibility testing was performed in HEp-2 cells grown in 96-well microtiter plates. The MIC was the lowest antibiotic concentration at which no inclusions were seen. The MBC was the lowest concentration which resulted in no inclusions after passage in antibiotic-free medium. Grepafloxacin was the most active quinolone tested with an MIC50 of 0.125 mg/l, MIC90 and MBC90 of 0.5 mg/l. Grepafloxacin may have a role in the treatment of C. pneumoniae infections, but prospective clinical studies utilizing culture are lacking.

Treating acute bacterial exacerbations of chronic bronchitis in patients unresponsive to previous therapy: sparfloxacin versus clarithromycin

The optimal antibiotic therapy for patients with acute bacterial exacerbations of chronic bronchitis (ABECB) who have failed to respond to previous oral antimicrobial therapy is not known; however, newer macrolide and fluoroquinolone antibiotics may be appropriate. This multicenter, randomized, double-masked, double-dummy study was undertaken to compare the efficacy and tolerability of sparfloxacin with those of clarithromycin in the treatment of ABECB. In 43 centers in the United States, 298 patients (52% male; age range, 19 to 92 years) were randomly allocated to receive a 400-mg loading dose of sparfloxacin, followed by 200 mg once daily, or clarithromycin 500 mg twice daily, for a total of 10 days. Signs and symptoms of ABECB were assessed at each of 4 visits, including a follow-up visit approximately 1 month after the completion of therapy. Efficacy was determined on the basis of the clinical and bacteriologic response rates in the clinically assessable population. Tolerability was assessed on the basis of patient reports, clinical evaluations, and laboratory tests. Of the 266 clinically assessable patients, 109 (85.2%) of 128 patients receiving sparfloxacin and 115 (83.3%) of 138 patients receiving clarithromycin had a clinically successful outcome (cure or improvement). The bacteriologic success rate (eradication of pathogen) was 88.9% (64 of 72 isolates) in the sparfloxacin group and 84.7% (83 of 98 isolates) in the clarithromycin group. Adverse events possibly or probably related to study drug included photosensitivity in 12 (8.3%) and rash in 6 (4.1%) of 145 patients in the sparfloxacin group, and diarrhea in 10 (6.5%), taste perversion in 9 (5.9%), and nausea in 8 (5.2%) of 153 patients in the clarithromycin group. Thus sparfloxacin was as well tolerated and as effective as clarithromycin in the treatment of patients with ABECB unresponsive to previous oral antimicrobial therapy. The overall rate of adverse events was comparable for the 2 study drugs, but the types of events differed.

Effects of food on the pharmacokinetics of sparfloxacin

Sparfloxacin, a fluoroquinolone with a broad antimicrobial spectrum and long elimination half-life, is indicated for the treatment of community-acquired pneumonia and acute bacterial exacerbations of chronic bronchitis in adult patients. The present study was undertaken to determine the effects of skim milk and a high-fat breakfast without milk on the single-dose pharmacokinetic characteristics of this antibiotic. The pharmacokinetics of a single 200-mg dose of sparfloxacin were assessed in a 3-way crossover study that included 23 healthy male volunteers who had fasted, had ingested 240 mL of skim milk, or had consumed a standard high-fat breakfast. The subjects' mean age and weight were 26.5 years and 73.2 kg, respectively; 17 were white, 5 Hispanic, and 1 black. Neither skim milk nor the high-fat breakfast had a statistically significant effect on sparfloxacin absorption, as reflected in the maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC). Ninety percent confidence limits for logarithmically transformed AUC from time zero to infinity and Cmax were within the 80% to 125% range, demonstrating that the rate and extent of sparfloxacin absorption with skim milk or a high-fat breakfast were not different from those under fasted conditions. As indicated by an increase in the time to Cmax from 3.6 to 5.4 hours, the high-fat breakfast slightly delayed the onset of sparfloxacin absorption. Skim milk and the high-fat breakfast did not significantly affect the elimination kinetics of sparfloxacin. Sparfloxacin was well tolerated in all 3 treatment groups. Despite the apparent delay in the onset of absorption, the bioavailability of sparfloxacin in the healthy male subjects in this study population was not affected by concomitant administration with skim milk or a high-fat meal. Accordingly, the results suggest that sparfloxacin can be administered without regard to the ingestion of milk or meals.

Comparison of the in vitro activity of and pathogen responses to sparfloxacin with those of other agents in the treatment of respiratory tract, urinary tract, and skin and skin-structure infections

The in vitro activity of and pathogen responses to sparfloxacin were compared with those of standard therapies for the treatment of patients with community-acquired pneumonia, complicated skin or skin-structure infections, urinary tract infections, acute bacterial exacerbations of chronic bronchitis, and acute maxillary sinusitis in 7 multicenter controlled trials in North America. Sparfloxacin was administered orally as a 400-mg loading dose followed by 200 mg once daily for up to 10 days. The bacteriologic efficacy of sparfloxacin (84% to 95%) was comparable to that of comparator drugs (77% to 100%). Sparfloxacin was generally 2 to 8 times more active (minimum inhibitory concentration for 90% of strains tested [MIC90]: 0.03 to 0.5 microg/mL) than comparators against common pathogens isolated in community-acquired infections, especially Streptococcus pneumoniae, including penicillin-resistant strains; Moraxella catarrhalis; Haemophilus influenzae; Streptococcus pyogenes; and Staphylococcus aureus. Sparfloxacin was also effective against Chlamydia and Mycoplasma species. The emergence of resistance was uncommon during sparfloxacin therapy (0.3% of 1100 cases). Higher area under the plasma concentration-time curve/MIC and maximum plasma concentration/MIC ratios for sparfloxacin were associated with clinical and bacteriologic efficacy, whereas lower ratios were associated with clinical and bacteriologic failure. The clinical efficacy of sparfloxacin (80% to 95%) was comparable to that obtained with the comparator drugs (71% to 92%). In addition, sparfloxacin was well tolerated and had an overall frequency of related adverse events similar to that of the comparators. There was a higher frequency of photosensitivity reactions but a lower level of digestive adverse events with sparfloxacin compared with comparators. Sparfloxacin is a suitable therapeutic alternative for the empiric treatment of respiratory tract infections owing to its favorable pharmacokinetic profile and activity against typical and atypical respiratory tract pathogens, even in geographic areas with a high incidence of penicillin resistance.

Sparfloxacin versus ciprofloxacin for the treatment of community-acquired, complicated skin and skin-structure infections

Fluoroquinolones have been shown to be effective in the treatment of complicated skin and skin-structure infections, in part because of their broad-spectrum antibacterial activity against causative pathogens that are resistant to older antimicrobial agents. We enrolled 603 adult patients (>58% male, >85% white) in a double-masked, double-dummy, randomized, multicenter trial to compare the efficacy and tolerability of sparfloxacin (400-mg loading dose followed by 200 mg once daily) with those of ciprofloxacin (750 mg twice daily) for 10 days in the treatment of community-acquired, complicated skin and skin-structure infections. The primary efficacy variable was clinical response, based on assessment of signs and symptoms, in the clinically assessable population. Patients in the sparfloxacin and ciprofloxacin groups were comparable with respect to demographic characteristics, underlying diseases, medical history, and laboratory test results. Wound infection was the most common diagnosis, and Staphylococcus aureus was the most frequently isolated pathogen. For the 475 clinically assessable patients, the clinical success rate (percentage of patients cured or improved) was 90.1% (210/233) with sparfloxacin and 87.2% (211/242) with ciprofloxacin. In this analysis (95% confidence interval [CI], -2.8 to 8.6) and the intent-to-treat analyses (95% CI, -4.2 to 6.2), results with sparfloxacin were statistically equivalent to those with ciprofloxacin (95% CI, -1 to 15.3). For bacteriologically assessable patients, eradication rates were 87.0% (141/162) with sparfloxacin and 79.9% (123/154) with ciprofloxacin (95% CI, -1 to 15.3). Eradication rates of S. aureus and coagulase-negative staphylococcal infections were 90.2% (101/112) with sparfloxacin and 77.9% (88/113) with ciprofloxacin. For patients with 2 or more pathogens at baseline (mixed infections), bacteriologic success was 87.6% for sparfloxacin and 77.9% for ciprofloxacin. Pseudomonas aeruginosa infections were eradicated or presumed eradicated in 71.4% (10/14) of sparfloxacin-treated patients and 87.5% (7/8) of ciprofloxacin-treated patients. Overall success rates in the bacteriologically assessable patients for sparfloxacin (84.6% [137/162]) and ciprofloxacin (78.6% [121/154]) were statistically equivalent (95% CI, -2.5 to 14.5). Tolerability was assessed in all patients who received study medication. The overall frequency of treatment-related adverse events was comparable in the 2 treatment groups (26.5% sparfloxacin, 23.3% ciprofloxacin). Drug-related adverse events involving the digestive system occurred in 7.1% of sparfloxacin-treated patients and 19.0% of ciprofloxacin-treated patients; photosensitivity reactions were reported in 11.1% of patients in the sparfloxacin group and 0.7% of patients in the ciprofloxacin group (P < 0.001). The mean change in QTc interval from baseline to the maximum on-treatment value was greater in the sparfloxacin group (9 milliseconds) than in the ciprofloxacin group (3 milliseconds) (P = 0.005; 95% CI, 0.002 to 0.010). The efficacy of sparfloxacin was comparable to that of ciprofloxacin in the treatment of community-acquired, complicated skin and skin-structure infections, including those caused by staphylococci, the most common pathogens. Sparfloxacin's once-daily regimen, high skin-tissue penetration, and improved activity against gram-positive cocci make it a therapeutic alternative to ciprofloxacin for patients who are not at risk for photosensitivity reactions or adverse events associated with prolongation of the QTc interval.

Safety profile of sparfloxacin, a new fluoroquinolone antibiotic

The safety profile of sparfloxacin, a newer fluoroquinolone antibiotic, was examined through an integrated analysis of safety data from 6 multicenter phase III trials. These consisted of 5 double-masked, randomized, comparative trials of sparfloxacin (a 400-mg oral loading dose followed by 200 mg/d for 10 days) versus standard therapies (erythromycin, cefaclor, ofloxacin, clarithromycin, and ciprofloxacin) and I open-label trial (noncomparative) in patients with: community-acquired pneumonia (2 trials); acute bacterial exacerbations of chronic bronchitis (1 trial); acute maxillary sinusitis (2 trials, one of which was the noncomparative trial); and complicated skin and skin-structure infections (1 trial). Overall, 401 (25.3%) of 1585 patients treated with sparfloxacin and 374 (28.1%) of 1331 receiving a comparator regimen experienced at least 1 adverse event considered to be related to the study medication. Photosensitivity reactions, usually of mild-to-moderate severity, were seen more frequently with sparfloxacin (7.4%) than with comparator agents (0.5%), whereas gastrointestinal reactions (diarrhea, nausea, dyspepsia, abdominal pain, vomiting, and flatulence), insomnia, and taste perversion were more common in patients taking comparator drugs (22.3% vs 12.1%, 4.3% vs 1.5%, and 2.9% vs 1.2%, respectively). Analysis of electrocardiographic findings showed that the mean change from baseline in QT interval corrected for heart rate (QTc) was significantly greater in sparfloxacin-treated patients (10 msec) than in patients given comparator drugs (3 msec), but no associated ventricular arrhythmias were detected. Adverse events led to discontinuation of study medication in 104 (6.6%) patients receiving sparfloxacin and 118 (8.9%) given com parator drugs. Sparfloxacin may be considered an appropriate choice for the treatment of certain community-acquired infections for patients who are not at risk for photosensitivity reactions or adverse events associated with prolongation of the QTc interval.