Disseminated Mycobacterium gordonae infection in a child with cystic fibrosis

Nontuberculous Mycobacterial Infections in Cystic Fibrosis

Nontuberculous mycobacteria (NTM) are important pathogens, with a longitudinal prevalence of up to 20% within the cystic fibrosis (CF) population. Diagnosis of NTM pulmonary disease in people with CF (pwCF) is challenging, as a majority have NTM infection that is transient or indolent, without evidence of clinical consequence. In addition, the radiographic and clinical manifestations of chronic coinfections with typical CF pathogens can overlap those of NTM, making diagnosis difficult. Comprehensive care of pwCF must be optimized to assess the true clinical impact of NTM and to improve response to treatment. Treatment requires prolonged, multidrug therapy that varies depending on NTM species, resistance pattern, and extent of disease. With a widespread use of highly effective modulator therapy (HEMT), clinical signs and symptoms of NTM disease may be less apparent, and sensitivity of sputum cultures further reduced. The development of a disease-specific approach to the diagnosis and treatment of NTM infection in pwCF is a research priority, as a lifelong strategy is needed for this high-risk population.

Nontuberculous Mycobacterial Infections in Cystic Fibrosis

Nontuberculous mycobacteria (NTM) are important emerging cystic fibrosis (CF) pathogens, with estimates of prevalence ranging from 6% to 13%. Diagnosis of NTM disease in patients with CF is challenging, as the infection may remain indolent in some, without evidence of clinical consequence, whereas other patients suffer significant morbidity and mortality. Treatment requires prolonged periods of multiple drugs and varies depending on NTM species, resistance pattern, and extent of disease. The development of a disease-specific approach to the diagnosis and treatment of NTM infection in CF patients is a research priority, as a lifelong strategy is needed for this high-risk population.

Clinical course and significance of nontuberculous mycobacteria and its subtypes in cystic fibrosis

BACKGROUND

Nontuberculous mycobacteria (NTM) infections in patients with cystic fibrosis (CF) is increasing globally. However, the related epidemiology, comorbidities, and clinical impact of NTM infection remains unclear in the progress of CF lung disease and patient survival.

METHODS

We performed a retrospective, case-control, cohort study (10 years), comparing NTM culture-positive CF patients (N = 28) to matched controls (N = 26). NTM positive patients were divided in to two groups of slow-growing (N = 17) and rapid- growing NTM (N = 8). Three patients were positive for both slow and rapid NTM. For independent group comparisons, a non-parametric Mann-Whitney test (Kruskal-Wallis test for more than two groups) was used to compare the continuous variables, and a Fisher's exact test was used for the categorical variables. Paired comparisons were performed using a Wilcoxon signed-rank test.

RESULTS

The prevalence of NTM isolation was 8%. The age at CF diagnosis was significantly lower in the slow-growing NTM group compared to the rapidly growing NTM group (P = 0.04). The median percent predicted forced expiratory flow of 25% - 75% (FEF25-75) was significantly higher before NTM acquisition in slow-growing (P = 0.013) and rapidly growing NTM group (P = 0.028). The slow-growing NTM group received significantly more penicillin/beta lactamase (P = 0.010) and rifampin (P = 0.042) following isolation. Macrolide use was significantly higher after isolation in both the slow-growing NTM (P = 0.018) and rapidly growing NTM groups (P = 0.042).

CONCLUSIONS

An earlier CF diagnosis was associated with a higher isolation of slow-growing NTM and greater antimicrobial use after infection. NTM acquisition is associated with a worsening of FEF25-75. Thus, both the early diagnosis and treatment of an NTM infection in patients with CF may positively impact lung function.

Nontuberculous Mycobacterial Infections in Cystic Fibrosis

Nontuberculous mycobacteria (NTM) are important emerging cystic fibrosis (CF) pathogens, with estimates of prevalence ranging from 6% to 13%. Diagnosis of NTM disease in patients with CF is challenging, as the infection may remain indolent in some, without evidence of clinical consequence, whereas other patients suffer significant morbidity and mortality. Treatment requires prolonged periods of multiple drugs and varies depending on NTM species, resistance pattern, and extent of disease. The development of a disease-specific approach to the diagnosis and treatment of NTM infection in CF patients is a research priority, as a lifelong strategy is needed for this high-risk population.

False-positive QuantiFERON TB-Gold test due to Mycobacterium gordonae

We report a case of QuantiFERON TB-Gold conversion associated to Mycobacterium gordonae in an elderly male from an assisted living facility without known risk factors for tuberculosis. This knowledge of environmental mycobacteria causing positive quantiferon assays is important to avoid unnecessary treatment of false-positive latent tuberculosis, especially in the absence of well-established positive predictive value of quantiferon conversion.