infectious diseases
Nontuberculous Mycobacterial Infections
Pulmonary disease
 complex (MAC) also causes pulmonary disease in middle-aged or older White men with previous lung problems such as Chronic Obstructive Pulmonary Disease (COPD) , Another important population subject to NTM infection and disease is patients with Cystic Fibrosis . With better management of CF, patients are living longer and therefore are more likely to develop complications such as NTM disease. Cough and expectoration are common, often associated with fatigue, weight loss, and low-grade fever. The course may be slowly progressive or stable for long periods. Respiratory insufficiency and persistent hemoptysis may develop. Fibronodular infiltrates on chest x-ray resemble those of pulmonary TB, but cavitation tends to be thin-walled, and pleural effusion is rare. So-called tree-and-bud infiltrates, seen on chest CT, are also characteristic of MAC disease. Sputum examination and culture are done to diagnosis MAC and to distinguish MAC infection from tuberculosis. Determination of drug susceptibility may be helpful for certain organism/drug combinations but can be done only in highly specialized laboratories. For MAC, susceptibility toclarithromycinis a predictor of therapeutic response. For moderately symptomatic disease due to MAC with positive sputum smears and cultures,clarithromycin500 mg orally 2 times a day orazithromycin600 mg orally once/day,rifampin(RIF) 600 mg orally once/day, andethambutol(EMB) 15 to 25 mg/kg orally once/day should be used for 12 to 18 months or until cultures are negative for 12 months. For progressive cases unresponsive to standard drugs, combinations of 4 to 6 drugs that includeclarithromycin500 mg orally 2 times a day orazithromycin600 mg orally once/day,rifabutin300 mg orally once/day,ciprofloxacin250 to 500 mg orally or IV 2 times a day,clofazimine100 to 200 mg orally once/day, andamikacin10 to 15 mg/kg IV once/day may be tried. Resection surgery is recommended in exceptional cases involving well-localized disease in young, otherwise healthy patients. M. kansasiiandM. xenopiinfections respond toisoniazid,rifabutin, and EMB, with or withoutstreptomycinorclarithromycin, given for 18 to 24 months.M. abscessusis a multidrug-resistant organism. Its isolates have in vitro resistance to most oral antibiotics but generally are susceptible to a limited number of parenteral antibiotics, includingtigecycline, imipenem,cefoxitin, andamikacin; treatment with at least 3 active drugs is recommended (see the2020 practice guideline on the treatment of nontuberculous mycobacterial pulmonary disease). All nontuberculous mycobacteria are resistant topyrazinamide. 