Comparison of trimethoprim-sulfamethoxazole with ampicillin in acute infectious exacerbations of chronic bronchitis: a double-blind crossover study

Clinical Significance of the Infection-FreeInterval in the Management of Acute Bacterial Exacerbations of Chronic Bronchitis

Rational and appropriate antibiotic use for patients with acute exacerbation of chronic bronchitis (AECB) is a major concern, as approximately half of these patients do not have a bacterial infection. Typically, the result of antimicrobial therapy for patients with acute bacterial exacerbation of chronic bronchitis (ABECB) is not eradication of the pathogen but resolution of the acute symptoms. However, the length of time before the next bacterial exacerbation can be another important variable, as the frequency of exacerbations will affect the overall health of the patient and the rate of lung deterioration over time. Clinical trials comparing antimicrobial therapies commonly measure resolution of symptoms in AECB patients as the primary end point, regardless of whether the exacerbation is documented as bacterial in nature. Ideally, the scientific approach to assessing the efficacy of antibiotic therapy for ABECB should include a measurement of acute bacterial eradication rates in patients with documented bronchial bacterial infection followed by measurement of the infection-free interval (IFI), ie, the time to the next ABECB. The use of these variables can provide a standard for comparing various antimicrobial therapies. As we learn more about how antibiotics can affect the IFI, treatment decisions should be adapted to ensure optimal management of ABECB for the long-term.

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.

Use of quinolones for the treatment of acute exacerbations of chronic bronchitis

The availability of a new generation of quinolones expands the choices of antimicrobials for therapy of acute exacerbations of chronic bronchitis. These agents have broad antimicrobial activity, including good in vitro activity against respiratory pathogens, and advantageous pharmacokinetic characteristics, including bronchial tissue penetration. Ciprofloxacin, enoxacin, ofloxacin, and temafloxacin have been evaluated in a number of clinical trials, compared to the reference agents ampicillin, amoxicillin (with and without clavulanate), cefaclor, doxycycline, and erythromycin. Ciprofloxacin, ofloxacin, and temafloxacin have generally demonstrated greater clinical success than enoxacin. While these agents are effective against many respiratory pathogens, Streptococcus pneumoniae and Pseudomonas aeruginosa infections appear to pose problems. Temafloxacin and ciprofloxacin have been compared; temafloxacin eradicated S. pneumoniae more efficiently and did not interact with theophylline. Fluoroquinolones are an important addition to the agents useful for bacterial exacerbations of chronic bronchitis.

Trimethoprim-sulfamethoxazole

The antimicrobial combination of trimethoprim and sulfamethoxazole is active in vitro against various gram-positive and gram-negative bacteria. Clinically, it is useful for prophylaxis and treatment of selected infections of the genitourinary, respiratory, and gastrointestinal tracts. Trimethoprim-sulfamethoxazole by itself or in combination with other antimicrobial agents is indicated for most Nocardia asteroides infections and is the antimicrobial agent of choice for Pneumocystis carinii pneumonia. The drug is relatively nontoxic in patients who do not have the acquired immunodeficiency syndrome (AIDS) and is available in both oral and intravenous forms. The native compounds and the metabolites of trimethoprim and sulfamethoxazole are excreted primarily in the urine. When the creatinine clearance is less than 30 ml/min, the dosage of trimethoprim-sulfamethoxazole should be adjusted.

Comparison of ciprofloxacin with ampicillin in acute infectious exacerbations of chronic bronchitis. A double-blind crossover study

Two separate acute bacterial exacerbations of chronic bronchitis and/or asthma were treated in 22 patients in a double-blind crossover study. One course of treatment consisted of 750 mg of ciprofloxacin twice daily and the other of 500 mg of ampicillin four times a day; each drug was given for 14 days. Patients were observed initially, every three to four days during therapy, and weekly during the post-therapy period. Observations that were recorded included graded chest symptoms and physical findings, vital signs, hematologic parameters, and objective sputum measurements (daily volume, purulence, differential quantitative cytology, bacterial counts, and physical properties). Both antibiotic regimens were effective in resolving these acute bacterial exacerbations. Paired t test analysis revealed that ciprofloxacin is as clinically effective as ampicillin in the treatment of acute bacterial exacerbations in chronic bronchial disease, and appears to be superior in clearing bacterial pathogens from the sputum.

Trimethoprim-sulfamethoxazole and other sulfonamides

Trimethoprim-sulfamethoxazole continues to be a useful antibiotic for common outpatient problems such as urinary tract infections, prostatitis, acute exacerbations of chronic bronchitis, and acute otitis media as well as for serious infections of the hospitalized patient including Pneumocystis carinii pneumonia, acute pyelonephritis, and some forms of gram negative meningitis. The other sulfonamides have a limited role.

Trimethoprim-sulfamethoxazole

The antimicrobial combination of trimethoprim and sulfamethoxazole is active in vitro against a variety of gram-positive and gram-negative bacteria. Clinically, it is useful for treatment and prophylaxis of various infections of the genitourinary tract and certain infections of the respiratory and gastrointestinal tracts. Trimethoprim-sulfamethoxazole by itself or in combination with other antimicrobial agents is indicated for most Nocardia asteroides infections. It is the antimicrobial agent of choice for Pneumocystis carinii pneumonia. The drug is relatively nontoxic in patients who do not have acquired immunodeficiency syndrome (AIDS), and it is available in oral and intravenous forms. The native compounds and the metabolites of trimethoprim and sulfamethoxazole are excreted primarily in the urine. When the creatinine clearance decreases to less than 30 ml/min, the dosage of trimethoprim-sulfamethoxazole should be adjusted.

Chronic bronchitis. Managing the disease and related infections

Chronic bronchitis is characterized by chronic, productive cough present on most days for at least three months of the year. Differential diagnosis must exclude an endobronchial obstructive lesion, asthma, nocturnal aspiration, bronchiectasis, cystic fibrosis, and immotile cilia syndrome. The most characteristic finding in patients with chronic bronchitis is hypertrophy of the mucous glands and goblet cells.