A double-blind comparison of the effects of cefaclor and amoxycillin on respiratory tract and oropharyngeal flora and clinical response in acute exacerbations of bronchitis

Comparison of first-line with second-line antibiotics for acute exacerbations of chronic bronchitis: a metaanalysis of randomized controlled trials

BACKGROUND

Although acute exacerbations of chronic bronchitis (AECBs) are common, there has been no metaanalysis that focused on the optimum regimen.

METHODS

To evaluate the comparative effectiveness and safety of first-line antimicrobial agents (ie, amoxicillin, ampicillin, pivampicillin, trimethoprim/sulfamethoxazole, and doxycycline) and second-line antimicrobial agents (ie, amoxicillin/clavulanic acid, macrolides, second-generation or third-generation cephalosporins, and quinolones) for the treatment of patients with AECB, in an era of increasing antimicrobial resistance among the microbes responsible for AECB, we performed a metaanalysis of randomized controlled trials (RCTs) retrieved through searches of the PubMed and the Cochrane databases.

RESULTS

Twelve RCTs were included in the metaanalysis. First-line antibiotics were associated with lower treatment success compared to second-line antibiotics in the clinically evaluable patients (odds ratio [OR], 0.51; 95% confidence interval [CI], 0.34 to 0.75). There were no differences among the compared regimens regarding mortality (OR, 0.64; 95% CI, 0.25 to 1.66) or treatment success (OR, 0.56; 95% CI, 0.22 to 1.43) in microbiologically evaluable patients, or adverse effects in general (OR, 0.75; 95% CI, 0.39 to 1.45) or diarrhea in particular (OR, 1.58; 95% CI, 0.74 to 3.35).

CONCLUSIONS

Compared to first-line antibiotics, second-line antibiotics are more effective, but not less safe, when administered to patients with AECB. The available data did not allow for stratified analyses according to the presence of risk factors for poor outcome, such as increased age, impaired lung function, airway obstruction, and frequency of exacerbations; this fact should be taken into consideration when interpreting the findings of this metaanalysis.

One hundred years of chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is an increasing health problem and one of the leading causes of morbidity and mortality worldwide, but knowledge about its pathogenesis has increased substantially in recent years. The disease results from interaction between individual risk factors (like enzymatic deficiencies) and environmental exposures to noxious agents, like cigarette smoking, occupational dusts, air pollution and infections in childhood. The main mechanisms that may contribute to airflow limitation in COPD are fixed narrowing of small airways, emphysema and luminal obstruction with mucus secretions. COPD is characterised by a chronic inflammatory process in the pulmonary tissue, with a pattern different from bronchial asthma, associated with extrapulmonary effects and is considered now a complex, systemic disease. Optimal therapeutic targeting of COPD depends on a clear understanding of the precise mechanisms of these complex processes and on early and correct evaluation of disease severity. A combination of pharmacological and non-pharmacological approaches is used to treat COPD. Bronchodilators are the mainstay of COPD treatment and can be combined with inhaled corticosteroids for greater efficacy and fewer side effects. The use of LTOT for hypoxemic patients has resulted in increased survival, and expanded drug therapy options have effectively improved dyspnoea and quality of life. Recent studies have documented the benefits of pulmonary rehabilitation. In addition, non-invasive mechanical ventilation offers new alternatives for patients with acute or chronic failure.

Cefaclor into the millennium

We review the discovery and development of the cephalosporins and subsequently cefaclor. Cefaclor is active against a wide range of commonly encountered bacterial pathogens, acting by inhibiting cell wall synthesis. Its in vitro activity compares favourably with other beta-lactam antibiotics. Its pharmacokinetic properties indicate that an 8-hourly dosing schedule is appropriate. In addition a delayed release formulation allowing twice daily dosage has been developed. The efficacy of both formulations of cefaclor has been verified by many clinical trials. Cefaclor has been widely used in infections of the respiratory tract (including otitis media), urinary tract and soft tissues. The results of therapy are summarized. The low incidence of adverse events is highlighted and the beneficial influence of this on compliance is described. Finally, the pharmaco-economics of cefaclor are considered.

Infective exacerbations of chronic bronchitis: relation between bacteriologic etiology and lung function

STUDY OBJECTIVE

In patients with severe COPD, acute infective exacerbations are frequent. Streptococcus pneumoniae and Haemophilus influenzae are the most commonly isolated bacteria in sputum cultures from these patients. We hypothesized that in patients with advanced disease, Gram-negative bacteria other than H influenzae play at least an equally important role.

METHODS

We evaluated clinical data and sputum culture results from 211 unselected COPD patients admitted to our hospital with an acute infective exacerbation of COPD. One hundred twelve patients fulfilled our protocol criteria of reliable microbiologic results and reproducible lung function tests; the patients were categorized according to the recently published three stages of severity.

RESULTS

Lung function tests revealed an FEV1 of > or =50% of the predicted value in 30 patients (stage I), an FEV1 of 35% to <50% of the predicted value in 30 patients (stage II), and an FEV1 of < or =35% of the predicted value in 34 patients (stage III). Bacteria were classified into three groups: group 1 contained S pneumoniae and other Gram-positive cocci; group 2, H influenzae and Moraxella catarrhalis; and group 3, Enterobacteriaceae and Pseudomonas spp. For all patients together, the most frequently isolated bacteria were group 3 organisms (Enterobacteriaceae and Pseudomonas spp, 48.2%), followed by group 1 organisms (S pneumoniae and other Gram-positive cocci, 30.4%), and group 2 organisms (H influenzae and M catarrhalis, 21.4%). In stage I patients, 14 of 30 had bacteria from group 1, seven of 30 had group 2, and nine of 30 had group 3. In stage II patients, eight of 30 had group 1 bacteria, 10 of 30 had group 2, and 12 of 30 had group 3. In stage III patients, 12 of 52 had group 1 bacteria, seven of 52 had group 2, and 22 of 52 had group 3. The three groups of bacteria causing infective exacerbations were unevenly distributed among the three severity stages of lung function (p=0.016).

CONCLUSION

There is a correlation between deterioration of lung function and the bacteria isolated from patients with infective exacerbations of COPD. In acute infective exacerbations, Enterobacteriaceae and Pseudomonas spp are the predominant bacteria in patients with an FEV1 < or =35% of the predicted value.

Changes in symptoms, peak expiratory flow, and sputum flora during treatment with antibiotics of exacerbations in patients with chronic obstructive pulmonary disease in general practice

BACKGROUND

Bacterial infections of the lower airways during an exacerbation in patients with asthma or chronic obstructive pulmonary disease (COPD) may be the cause of an exacerbation or the consequence of a viral infection or an increase in airways limitation. To determine whether bacterial infection is an important component in the pathogenesis of an exacerbation, the effects of antimicrobial treatment must be studied.

METHODS

Patients with asthma or COPD seen in general practice were studied in a double blind randomised manner to investigate whether the antimicrobial drugs amoxicillin (500 mg three times daily), cotrimoxazole (960 mg twice daily), or a placebo, each when added to a short course of oral corticosteroids, can accelerate recovery from exacerbations. Patients were instructed to contact their own physician early in the morning when complaints of increased shortness of breath, wheezing, or exacerbations of cough with or without sputum production occurred. Treatment effects were evaluated over the next 14 days by studying symptom scores (wheeze, dyspnoea, cough with and without mucus production, and awakening with dyspnoea), peak expiratory flow values (PEF, expressed as % predicted), and sublingual temperature. Bacteriological study of the sputum was made at the onset of an exacerbation and 7, 21 and 35 days afterwards.

RESULTS

Of 195 patients enrolled 71 (36%) contacted their physician for symptoms of an exacerbation. Symptoms improved in all three groups, improvements ranging from 0.54 to 0.75 points per day on a four point scale. PEF% predicted showed improvements in the three groups after the exacerbation, ranging from 0.34% to 0.78% predicted per day, finally returning to baseline values. Sublingual temperature did not change. Six of 71 patients consulted their physician because of a relapse between four and 24 days after the start of treatment. In only two of the 50 sputum samples, collected during an exacerbation, and which contained > or = 10(5) bacteria in culture sensitive to the chosen antibiotic given, did any benefit from antimicrobial treatment occur. During the recovery period sputum purulence improved irrespective of antibiotic treatment.

CONCLUSIONS

Antibiotics given with a short course of oral prednisolone during an exacerbation do not accelerate recovery as measured by changes in peak flow and symptom scores in ambulatory patients with mild to moderate asthma or COPD when treated by their general practitioners. Moreover, antibiotics do not reduce the number of relapses after treating an exacerbation.