Bacteriology and Inflammation in Bronchiectasis

Bronchiectasis is a chronic disease arises from progressive airway inflammation and infection. It has been postulated that bacterial infection triggers intense airway inflammation leading to acute exacerbation of bronchiectasis. Antibiotics have been the most potent medications for the treatment of bronchiectasis, however, the sputum bacterial load and inflammatory indices at steady-state and exacerbation remain largely unknown. The investigation might shed light on the roles that antibiotics play in acute exacerbation of bronchiectasis and uncover the mechanisms on why a subgroup of individuals do not respond satisfactorily.

Bronchiectasis is a chronic disease arises from progressive airway inflammation and infection. Pro-inflammatory mediators, the products of activated neutrophils recruited to the inflamed sites, are released in bronchiectatic airways and mediate cascades of neutrophil infiltration. This suggests that bacterial infection plays a pivotal role in the neutrophil-derived inflammation leading to the vicious cycle that perpetuates the development of airway destruction and might result in acute exacerbation. Treatments targeting at bacterial infection is therefore necessary, particularly for those with acute exacerbation of bronchiectasis.

Although short- and long-term administration of antibiotics have been evidenced to markedly suppress bacterial colonization and inflammatory indices, the roles that potent antibiotics play in patients with exacerbation of bronchiectasis are unclear. The assessment of bacterial infection and sputum and systemic inflammation during steady-state, acute exacerbation and recovery from exacerbation of bronchiectasis may clinically shed light on and indicate the efficacy of antibiotic treatments.

Furthermore, a subgroup of patients may experience the acute exacerbation that may stem from non-bacterial pathogens. There has been a dire need to compare the changes in sputum bacterial load and inflammatory indices based on sputum bacteriology. This may help uncover the mechanism of different responses to antibiotic treatment in patients who had varying bacteriologic profiles.

Unlike assessment of chronic obstructive pulmonary disease, few clinical indices for appraisal of onset of exacerbation and efficacy of treatments are available. Of these, the 24-hour sputum volume, microbial clearance, C-reactive protein (CRP) and St George's Respiratory Questionnaire have been validated. In the present study, we employed sputum bacteriology and inflammatory indices, including the aforementioned parameters, for assessment.

Eligibility Criteria:
Inclusion Criteria:

* Patients of either sex and age between 18 and 70 years

Exclusion Criteria:

* Patient judged to have poor compliance
* Female patient who is lactating or pregnant
* Patients having concomitant severe systemic illnesses (i.e. coronary heart disease, cerebral stroke, uncontrolled hypertension, active gastric ulcer, malignant tumor, hepatic dysfunction, renal dysfunction)
* Miscellaneous conditions that would potentially influence efficacy assessment, as judged by the investigators
* Participation in another clinical trial within the preceding 3 months