The role of antimicrobial therapy in the treatment of ABECB remains controversial despite numerous therapeutic trials of antibiotics for more than 50 years. Most comparative trials have found equivalence in the use of antimicrobials. Differences in study end points, differences in patient groups studied, and variations in antibiotics used have made the comparison of these studies difficult. Not all antibiotics used to treat ABECB have the same spectrum of activity or pharmacokinetic properties. Therefore, numerous factors should be considered when selecting an antimicrobial agent.
Chronic bronchitis for research purposes is defined as a daily cough with sputum production for at least three months, two years in a row. Chronic bronchitis is a diagnosis usually made based on clinical findings of a long term persistent cough usually associated with tobacco abuse. From a pathologic standpoint, characteristic microscopic findings involving inflammatory cells in seen in airway tissue samples make the diagnosis. When referring to pulmonary function testing, a decrease in the ratio of the volume of airflow at 1 second when compared to total airflow is less than 70%. This confirms the presence of obstructive airways disease of which chronic bronchitis is one type. Certain findings can be seen on imaging studies ( chest X-ray , and CT or MRI of the lungs) to suggest the presence of chronic bronchitis; usually this involves an appearance of thickened tubes.