Treatment of atypical mycobacterial disease

Validation of a multistage asthma case-detection procedure for elementary school children

OBJECTIVE

The purpose of this study was to validate a 3-stage asthma case-detection procedure for elementary school-aged children.

METHODS

The study was performed in 10 elementary schools in 4 inner-city school systems, with a total enrollment of 3539 children. Results of the case-detection procedure were compared with the diagnosis of an asthma specialist study physician, to determine the sensitivity and specificity of the case-detection procedure.

RESULTS

Ninety-eight percent of children returned the asthma symptoms questionnaires, and 79% of those children consented to additional testing. Results indicated that the 3-stage procedure had good validity, with sensitivity, specificity, and predictive value of 82%, 93%, and 93%, respectively. A 2-stage procedure using questionnaires and spirometry had similar validity, with sensitivity, specificity, and predictive value of 78%, 93%, and 93%, respectively. However, given the time and expense associated with the 2- or 3-stage procedure and the difficulty of obtaining physician follow-up evaluation of the case-detection diagnosis, schools may prefer to use a 2-item questionnaire that has a lower sensitivity (66%) but higher specificity (96%) and predictive value (95%).

CONCLUSIONS

Case-detection programs are generally well received by school personnel and can identify children with unrecognized or undiagnosed disease, as well as those with a current diagnosis but poorly controlled disease. This study yields substantial information regarding the validity, yield, and specific types of children who might be identified with the use of such procedures. For the choice of the method of case detection used in a school, the strengths and weaknesses of each procedure, as well as the resources available for case detection, physician referral, and follow-up procedures, must be considered.

Imaging of Non-tuberculous (Atypical) Mycobacterial Pulmonary Infection

Pulmonary infections due to mycobacterial organisms are increasing in incidence. Non-tuberculous (atypical) mycobacteria (NTM) represent a significant proportion of mycobacterial infections and may prove difficult to diagnose due to their non-specific clinical and radiographic presentations. An increasing volume of radiological data is now available for the more common non-tuberculous mycobacterial infections, and we have summarized the imaging features found in such cases, identifying radiographic features that would favour the diagnosis of a non-tuberculous mycobacterium and that, in some cases, suggest a specific organism.

Management of non-tuberculous mycobacterial peri-sialadenitis in children: the Sheffield otolaryngology experience

Non-tuberculous mycobacterial infection (NTM) has been recognized as an important cause of infection in the head and neck in children since 1956. It is important to differentiate NTM from the more serious Mycobacterium tuberculosis (TB) since the management differs significantly. The causative organisms of NTM infection are resistant to the most commonly used anti-tuberculous preparations, though they do show sensitivity to the newer antibiotics such as clarithromycin, ciprofloxacin and azithromycin. Between 1986 and 1997, 15 patients with NTM infection involving the major salivary glands were treated at the Sheffield Children's Hospital Department of Otolaryngology. There were 11 girls and four boys. In all patients the onset of symptoms was between September and April. Resolution occurred in two patients without surgery. The remaining 13 underwent formal surgical exploration with excision of the mass, associated nodes and of the overlying skin if necessary. There were nine parotid explorations. There were no long-term facial nerve deficits as a result of surgery and no recurrence of the disease. Co-operation between the Paediatrician and the Otolaryngologist is important for effective management since NTM may also affect the lungs, soft tissues, bones and joints. Diagnosis relies upon culture, histology, chest radiography, purified protein derivative (PPD) testing, clinical features and skin testing. The use of antibiotics such as azithromycin with ciprofloxacin may be justified while waiting for the results of investigations, especially with small, early lesions, as resolution is possible. In patients who have no history of exposure to TB, are not immunocompromised, have a normal chest radiograph and have a Mantoux test with < 15 mm diameter induration, the treatment should be surgical excision rather than prolonged antibiotic therapy.

Treatment of pulmonary disease caused by Mycobacterium kansasii: results of 18 vs 12 months' chemotherapy

SETTING

Chest Clinic, Sant Pau Hospital, Barcelona, Spain.

OBJECTIVE

To assess the therapeutic response of pulmonary disease due to Mycobacterium kansasii to 12 and 18 months of chemotherapy.

DESIGN

28 patients with criteria of pulmonary disease caused by M. kansasii not associated with HIV-infection were identified in our department in the period 1985-91 (24 male, 4 female, mean age 56 +/- 12 years). 14 patients were treated with rifampicin-isoniazid-ethambutol daily for 12 months (ethambutol only for the first 6 months), and 14 with the same regimen for 18 months. The follow-up after treatment was 12-30 months.

RESULTS

All patients showed improvement of radiographic manifestation of disease and sputum conversion (mean time: 4.5 +/- 2 months). The adverse drug effects were minimal. No failures were detected, and only one patient (3.5%), in the group of 12-month chemotherapy, relapsed after finishing the treatment.

CONCLUSIONS

Our findings suggest that pulmonary disease due to M. kansasii has an effective response to 12-month chemotherapy regimen and that it is not necessary to prolong the administration of ethambutol for more than 6 months.

Activities of clarithromycin against eight slowly growing species of nontuberculous mycobacteria, determined by using a broth microdilution MIC system

MICs of clarithromycin against 324 clinical isolates belonging to eight species of slowly growing nontuberculous mycobacteria were determined by using a broth microdilution system. Isolates were inoculated into twofold drug dilutions in Middlebrook 7H9 broth (pH corrected to 7.4) and then incubated at 30 degrees C for 7 days for Mycobacterium marinum and for 14 days for all other species. The MIC for 90% of the strains (MIC90) was less than or equal to 0.5 micrograms/ml for isolates of Mycobacterium gordonae (6 strains), Mycobacterium scrofulaceum (5 strains), Mycobacterium szulgai (6 strains), and Mycobacterium kansasii (35 strains). MICs for M. marinum (25 strains) and Mycobacterium avium complex (237 strains) were higher, but 100% and 89% of the strains, respectively, were susceptible to less than or equal to 4 micrograms/ml. In contrast, MICs for five of six M. simiae strains were greater than 8 micrograms/ml, and the range of MICs for Mycobacterium nonchromogenicum varied from less than or equal to 0.125 to 8 micrograms/ml. For the 237 isolates of M. avium complex, the MIC50 was 2 micrograms/ml and the MIC90 was 8 micrograms/ml. MICs for most isolates (77%) were in the 1- to 4-micrograms/ml range. For the 80 isolates in this group known to be from AIDS patients, the MIC50 was 4 micrograms/ml and the MIC90 was 8 micrograms/ml. These MIC studies combined with preliminary clinical trials suggest that clarithromycin may be useful for drug therapy of most species of the slowly growing nontuberculous mycobacteria except M. simiae.

Mycobacterium fortuitum lung abscess: resolution with prolonged trimethoprim/sulfamethoxazole therapy

Mycobacterium fortuitum rarely causes lung disease despite its sporadic isolation as a saprophytic colonizer from sputum or saliva. If pulmonary disease occurs, it is usually indolent in nature. The case presented appears to be the first reported case of a M. fortuitum lung abscess that was successfully treated with a prolonged course of trimethoprim/sulfamethoxazole. The patient remains well without evidence of recurrence nearly 2 yr after the cessation of therapy.

Treatment of pulmonary disease caused by opportunist mycobacteria

Opportunist mycobacterial infections localised to the chest may be treated with combinations of standard antimycobacterial drugs. The combination of rifampicin and ethambutol seems to be particularly effective, both in vivo and in vitro. In vitro sensitivity testing with single drugs may have a role in the future when the levels of in vitro resistance compatible with the clinical response to treatment are eventually established. Sensitivity testing against drugs in combination may prove useful for modifying treatment regimens in those patients who either fail to respond to initial chemotherapy or relapse. Further evidence on this will, it is hoped, emerge from the prospective studies currently in progress.

Nontuberculous mycobacterial lung disease. Substantiation of a less aggressive approach

A nonsurgical, less aggressive, less toxic chemotherapeutic protocol for the management of nontuberculous mycobacterial (NTB) pulmonary infections has been uniformly applied to patients in our institution between 1972 and 1985. Forty-three nonimmunocompromised patients with active lung disease caused by Mycobacterium avium-intracellulare (MAI) (n = 26), M kansasii (n = 16), and M xenopi (n = 1) were identified retrospectively. Eighteen MAI patients were treated with three or four antituberculosis agents resulting in sputum conversion and clinical improvement in 12 (67 percent). Additionally, 11 out of 16 (69 percent) patients completing therapy or still undergoing therapy for persistent MAI disease, achieved sputum conversion and clinical improvement after prolonged therapy (3.6 +/- 0.5 years [SEM]). When M kansasii was identified as the etiologic agent, all patients were treated with four or fewer antituberculosis agents and 14 out of 16 patients (88 percent) achieved sputum conversion and clinical improvement throughout the follow-up period. We conclude that the use of three or four chemotherapeutic agents in the treatment of NTM lung disease provides an excellent probability of successful outcome even in MAI infections.

Ankylosing spondylitis lung disease and Mycobacterium scrofulaceum

The development of apical pulmonary fibrosis and bullous disease is a rare but well recognized extra-articular manifestation of ankylosing spondylitis (AS). The fibrobullous disease is usually asymptomatic and diagnosed at an incidental radiological examination. When symptoms do develop, they are usually due to superimposed colonization or infection by bacteria, fungi or mycobacteria. Only six cases of non-tuberculous mycobacterial superinfection in AS have been reported. We report a patient with AS and progressive apical fibrobullous disease in whom Mycobacterium scrofulaceum was repeatedly cultured over a 12-year period.