Bacteria isolated from the airways of patients presenting with an acute exacerbation of non-cystic fibrosis bronchiectasis: a prospective study
Background: There is little information available on the precipitating bacteria in acute exacerbation of bronchiectasis in developing countries. The Standard treatment guidelines and essential medicine list for South Africa’s1, recommendations for treating acute exacerbation of bronchiectasis relies on data from non-developing countries, which may not reflect the South African situation. Therefore a study was preformed to identify the most common bacteria occuring in our setting and determine the appropriateness of the current recommended empiric antibiotic choices. Empiric therapy that is currently based on the Guidelines for non-cystic fibrosis Bronchiectais published in 2010 by Thorax, an International journal on respiratory medicine.2 Objective: 1. Identify and document the frequency of bacteria cultured from the sputum samples of patients presenting with acute exacerbation of non-cystic fibrosis bronchiectasis at the Helen Joseph Hospital. 2. Determine the appropriateness of current standard treatment guidelines’ first line antibiotic choices for the bacteria cultured in our patients that present with acute exacerbation of non-cystic fibrosis bronchiectasis. Methods: A prospective cohort study of 81 patients that presented with acute exacerbation of non-cystic fibrosis bronchiectasis. The diagnosis of bronchiectasis was suspected on a combination of clinical manifestations and chest radiography. Where possible definite diagnosis or confirmation of suspected diagnosis was made by HRCT. Patients was classified as definite or suspected bronchiectasis, if outpatient HRCT was still pending. Three sputum samples were collected on admission from these patients. The sputum samples were obtained prior to the initiation of antibiotics. The samples were tested for Tuberculosis using Gene Expert, Acid-Fast Bacillus microscopy and culture. A Bartlett score and bacterial microscopy, culture and sensitivity was also performed. (These investigations are part of the normal standard of care as described in the National Department of Health Standard Treatment Guidelines and Essential medicinelist.1) Results: A pathogenic bacteria was isolated in only 30% of cases. The most common bacteria cultured from the sputum samples of patients presenting with acute exacerbation of non-cystic fibrosis bronchiectasis were Haemophilus influenzae (7.4%), Pseudomonas aeruginosa (4.9%), Klebsiella pneumoniae (3.7%), Escherichia coli (1.2%) and Acinetobacter baumannii (1.2%). Of the subjects 7.4% had Mycobacterium tuberculosis isolated from their sputum. The 60% of the pathogenic bacteria isolated were sensitive to the first line antimicrobials recommended. Conclusion: The most common bacteria cultured from the sputum samples of patients presenting with acute exacerbation of non-cystic fibrosis bronchiectasis at the Helen Joseph Hospital is comparable to previous studies done in developed countries.3,5,22 Since our yield of positive cultures was lower then that obtained in other studies, there will definetly be value in re-attempting this study on a larger scale. The results suggest that the current South African treatment guidelines are appropriate for the treatment of acute exacerbation of bronchiectasis in our setting, as more then 60% of the pathogenic bacteria was sensitive to the fist line antimicrobial.
A research report submitted in partial fulfillment of the requirements for the degree of Master of Science in Medicine (Internal Medicine) to the Faculty of Health Sciences, School of Clinical Medicine, University of Witwatersrand, Johannesburg, 2022