For Cystic Fibrosis Patients, Targeted Bacterial Testing Could Decrease Premature Death
Cystic Fibrosis (CF) is the most frequent, lethal genetic disorder, affecting roughly 30,000 people in the United States. Early death occurs mainly from chronic lung disease caused by persistent lower airway infection and inflammation. There are several important airway pathogens that are detrimental to CF patients, such as Staphylococcus aureus and Pseudomonas aeruginosa. However, isolation of mycobacteria in the sputum of patients with CF has been significantly increasing over the past 15 years, especially resistant nontuberculous mycobacteria (NTM) strains. This is probably a consequence of a certain degree of immunoincompetence resultant from long-term antimicrobial treatment. In single-center studies, the prevalence of NTM infection has varied from 3 to 28%, depending on the patient population studied, and in a multi center study of American CF patients aged 10 years or older conducted from 1992 to 1998, the overall prevalence of NTM was 13%.
A team of researchers from Istanbul Medical Faculty recently set out to determine the prevalence of mycobacterium species (spp.) and antimicrobial susceptibility in Turkish CF patients, analyzing 376 sputa from 130 CF patients in a 5.5-year period, using the Bactec 460 TB System, a semi-automated radiometric mycobacterial growth detection method, and the E test, a well-established method for antimicrobial resistance testing.
The study, entitled, “Prevalence and drug resistance of mycobacteria in Turkish cystic fibrosis patients” and published in the Annals of Clinical Microbiology and Antimicrobials journal, discovered that in total, 28 (7.44%) Mycobacterium spp. were isolated from 8 (6.15%) CF patients, of these, 5 isolates (17.9%) were identified as Mycobacterium tuberculosis complex, 14 (50%) as Mycobacterium abscesses and nine (32.1%) as Mycobacterium lentiflavum. Additionally, all of these Mycobacterium tuberculosis complex isolates were susceptible to different types of antibiotics, such as streptomycin, isoniazid, rifampicin, and ethambutol, a bacteriostatic antimycobacterial drug.
However, in some NTM strains, resistance to some antibiotics was detected.
The authors conclude that in pediatric CF patients, it should become common practice to preform specific mycobacterial analysis of sputum specimens and susceptibility testing, since it could allow early detection and identification of these bacteria, leading to its eradication at an early stage, therefore decreasing the probability of premature death in CF patients.