Pulmonary Mycobacterium kansasii Infection in Israel, 1999-2004: Molecular Characterizations
Twenty M kansasii isolates underwent molecular characterization. Eighteen isolates were found to be M kansasii type I, and 2 isolates were M kansasii type II.
Table 2 summarizes the drug sensitivity of the M kansasii isolates. All isolates were sensitive to rifam-picin, all but one isolate (borderline) were sensitive to ethambutol and ofloxacin, and all but two isolates (borderline) were sensitive to clarithromycin. Sensitivity rates to ethionamide and cycloserine were 91% and 94%, respectively, with one isolate resistant to each. A high rate of resistance was noted for ciprofloxacin (10 isolates, 29%) and capreomycin (26 isolates, 74%); 2 isolates (6%) were highly resistant to capreomycin. add comment
All our patients were treated with rifampicin (600 mg), ethambutol (25 mg/kg for the first 2 months, then 15 mg/kg), and clarithromycin (1,000 mg/d) administered daily for at least 12 months of negative sputum culture results. The mean duration of treatment was 21 ± 7.2 months.
All 56 patients survived the M kansasii infection. The mean duration of positive culture results after the start of treatment was 8.9 ± 10.3 months. Older patients had more noncavitary disease than younger patients (p = 0.01, r = 0.35). Patients with bronchiectasis had a higher rate of hemoptysis than patients without bronchiectasis (p = 0.04, r = 0.30). Patients who had chronic underlying lung disease had more fever and night sweats than patients who did not (p = 0.0.3, r = 0.31).
Patients receiving immunosuppressive medication had cough as a presenting symptom less often than patients without a recognized immune defect, in addition to less cavitation and less upper-lobe predominance (p = 0.03, r = 0.31; p = 0.009, r = 0.49; and p = 0.03, r = 0.31, respectively). They also had lower sensitivity to ofloxacin (p = 0.006, r = 0.48).
The characterization of the pulmonary infections caused by M kansasii in nonendemic areas may have important implications for the early introduction of appropriate treatment. So far, data remain sparse. Our study is one of the largest conducted on the clinical features of M kansasii infection in a nonendemic area, and the first one to come from Israel.
Table 2—Drug Sensitivity of M kansasii (n = 56)
Drugs | Sensitive | Borderline | Resistant | HighlyResistant |
Rifampicin | 45 (100) | |||
Ethambutol | 42 (98) | 1(2) | ||
Clarithromycin | 34 (94) | 2 (6) | ||
Ciprofloxacin | 11 (32) | 13 (38) | 10 (29) | |
Capreomycin | 3(9) | 4(11) | 26 (74) | 2(6) |
Ethionamide | 33 (91) | 2 (6) | 1(3) | |
Cycloserine | 35 (94) | 1 (3) | 1 (3) | |
Ofloxacin | 33 (97) | 1 (3) |