Impact of a 14-year screening programme on tuberculosis transmission among the homeless in Paris.

OBJECTIVE: To evaluate the impact of an active case-finding programme on tuberculosis (TB) transmission in homeless shelters in Paris, France. DESIGN: Between 1994 and 1997, an active case-finding programme was implemented in homeless shelters using a mobile radiological screening unit, and continued from 1997 to 2007. During these periods, the strains isolated from TB cases diagnosed in the homeless were genotyped by restriction fragment length polymorphism analysis using the insertion sequence IS6110 as a probe. RESULTS: Between 1994 and 2007, 313 new TB cases were diagnosed among the homeless population: 179 through the programme among shelter users, and 134 among homeless people not using shelters. Half of the strains were clustered in 35 distinct patterns (2-48 cases/cluster). The clustering of TB cases steadily decreased in shelters during the 13 years of the survey, from 14.3 to 2.7 related cases per year (P < 0.01) and from 75% to 30% of related cases among all TB cases (P < 0.01). In contrast, there was only a slight trend towards a decrease in homeless people not using shelters. CONCLUSION: Active case finding in homeless shelters resulted in a decrease in case clustering, mainly in shelter users. Genotyping contributed to confirming the positive impact of the intervention.

First isolation of Mycobacterium microti (Llama-type) from a dog.

We report the first isolation of Mycobacterium microti from a dog with lesions of acute peritonitis. The isolate was demonstrated to be M. microti of Llama-Type by spoligotyping. Epidemiological implications of the isolation of this possibly zoonotic agent from a dog are discussed.

[Mycobacterium fortuitum skin infection occurring after a facelift]. / Infection cutanée à Mycobacterium fortuitum après lifting.

INTRODUCTION: Mycobacterium fortuitum skin infections are rare and usually iatrogenic. We report a case with cervical involvement following a facelift. OBSERVATION: A 65 year-old woman, without past history, underwent bilateral surgical facelift, complicated by cutaneous necrosis and treated with directed healing at home. Six weeks later, an abscessed nodule appeared under the left maxillary and was drained surgically. Then other pre-auricular and left cervical inflammatory nodules appeared without adenopathy or fever. M. fortuitum was isolated in bacteriological samples. The initially probabilistic antibiotherapy with carithromycin, subsequently adapted with amikacine and cirprofloxacine and then imipeneme for a total duration of 3 months, led to the clinical cure. DISCUSSION: Mycobacterium fortuitum is a rapidly growing, ubiquitous, mycobacteria responsible for nosocomial infections in immunocompetent patients, notably following plastic surgery. Contamination occurs where there has been a rupture in the skin barrier through contact with a vector (water, surgical material, antiseptic.). Treatment, which is not codified, consists in the association of surgery and antibiotics for several months.

Impact of iron loading on the activity of isoniazid or ethambutol in the treatment of murine tuberculosis.

OBJECTIVE: To assess the impact of iron loading on the activity of isoniazid and ethambutol in the treatment of murine tuberculosis. DESIGN: Iron-loaded and iron-normal female Balb/C mice infected with 1.5 x 10(7) colony forming units of Mycobacterium tuberculosis were treated with either isoniazid or ethambutol for 28 days. RESULTS: For both treatments, the outcome was impaired by the iron loading: bactericidal activity of isoniazid was partially but significantly reduced and ethambutol bactericidal activity was totally inhibited. CONCLUSION: The treatment of tuberculosis in patients with iron loading should be longer than for normal patients or should contain an additional drug.

Multiple cerebral abscesses as a complication of Mycobacterium fortuitum infection.

Mycobacterium fortuitum is a rapidly growing, nontuberculous mycobacteria that has rarely been associated with central nervous system impairment. We describe the case of a patient who developed multiple cerebral abscesses revealing Mycobacterium fortuitum infection. Brain biopsy specimens showed suppurative, noncaseating, granulomatous inflammation consisting of epithelioid histiocytes and multinucleated giant cells. All clinical signs and CT scan cerebral lesions disappeared after institution of appropriate antimycobacterial therapy.

Iron and Mycobacterium tuberculosis infection.

BACKGROUND: iron is known to play a role in the susceptibility to and outcome of several infections. In view of the increasing worldwide problem of tuberculosis, it may be important to ascertain whether this is also the case with this infection. OBJECTIVES: (1) to review studies conducted in vitro, in experimental animals, and in humans that provide evidence that iron status may influence the occurrence and outcome of tuberculosis. (2) To perform an in vivo study in mice, examining the effect of iron loading on experimental infection caused by a virulent strain of Mycobacterium tuberculosis. RESULTS: we studied the effect of iron loading on the growth in spleen and lungs of a virulent strain of M. tuberculosis, injected i.v. in female Balb/C mice. At sacrifice on day 42 after the experimental infection, the iron-loaded mice presented a significantly enhanced multiplication of M. tuberculosis in both the spleen and the lungs, when compared to the mice without iron loading. CONCLUSION: Most of the studies, including our experimental study in mice, tend to suggest that an excess of iron may enhance the growth of M. tuberculosis and worsen the outcome of human tuberculosis.

Evaluation of the new MB redox system for detection of growth of mycobacteria.

We evaluated a new mycobacterial culture system, MB Redox, for recovery rate and time to detection of mycobacteria from 742 consecutive respiratory specimens and compared the results to those found with Löwenstein-Jensen (LJ) medium. Twenty specimens (2.7%) were positive for M. tuberculosis: 17 on LJ medium and 19 in MB Redox, with 16 specimens positive in both media. In addition, 24 specimens (3.2%) were positive for nontuberculous mycobacteria (NTM), 20 on LJ medium, 18 in MB Redox, and 14 in both media. For M. tuberculosis, the mean times to detection were 28.9 days on LJ medium and 23.6 days in MB Redox, and for NTM, the mean times to detection were 40.6 days on LJ medium and 32.3 days in MB Redox.

Mycobacterial lung disease in cystic fibrosis: a prospective study.

BACKGROUND: Patients with cystic fibrosis (CF) may be predisposed to airway infections with unusual organisms, such as mycobacteria. The aim of the study was to determine the incidence and clinical picture of mycobacterial infection in CF children. METHODS: At least 2 acid-fast bacillus (AFB) smears and mycobacterial cultures were performed on a prospective basis on 682 sputum specimens from 106 patients during a 1-year period. RESULTS: Thirty-three percent of the cultures were contaminated with other bacteria. Seven children had at least one sputum culture positive for one mycobacterium. Five children had only one positive AFB culture. Their clinical status and lung function remained stable during follow-up. Two teenagers with severe lung disease had several positive AFB smears and cultures for Mycobacterium chelonae and Mycobacterium abscessus. The isolation of M. chelonae and M. abscessus was associated with a clinical and functional decline. Clarithromycin treatment resulted in temporary improvement with the disappearance of the mycobacteria after 6 months of treatment. This prospective study shows an incidence of 2.3% for positive cultures. The prevalence was 6.6% for mycobacterial colonization but only 1.9% for mycobacterial lung disease in our pediatric population. CONCLUSIONS: We recommend performing AFB smears and cultures in CF children with severe lung disease and/or during a lung exacerbation. In these patients persistence of M. chelonae or M. abscessus in sputum should lead to consideration of treatment with clarithromycin.

Tuberculosis caused by Mycobacterium africanum associated with involvement of the upper and lower respiratory tract, skin, and mucosa.

Cutaneous tuberculosis is rarely seen in industrialized countries and is usually caused by Mycobacterium tuberculosis. We report a case of cutaneous tuberculosis with bilateral nodular scleritis, nasal sinus invasion, and nasal septum perforation (confirmed by computed tomography scans of the sinuses), associated with pulmonary infiltrates and mediastinal adenopathy, in an African woman. Mycobacterium africanum was recovered from the sputum after 8 weeks of culture in Löwenstein-Jensen medium. To our knowledge, this is the first description of M. africanum associated with cutaneous tuberculosis and nasal sinus invasion.

Chloroquine does not enhance the activity of clarithromycin against multiplication of Mycobacterium avium within human macrophages.

SETTING: Chloroquine, an alkalinizing lysosomotropic agent, enhances the intracellular activity of antibiotics against Mycobacterium tuberculosis or Coxiella burnetii. OBJECTIVE: To determine if chloroquine modifies the activity of clarithromycin, less effective at acidic pH, against intracellular Mycobacterium avium. DESIGN: The activity of clarithromycin (4 micrograms/ml) against the MO-1 strain of M. avium was evaluated within human macrophages in presence of chloroquine (5 micrograms/ml). The minimal inhibitory concentration of clarithromycin for the strain was 2 micrograms/ml. RESULTS: While clarithromycin alone did decrease the intracellular infection at day 7 of culture (P < 0.01), chloroquine alone did not impede the intracellular growth of M. avium, and did not enhance the activity of clarithromycin. CONCLUSION: Chloroquine should not improve clarithromycin treatment against M. avium infection.

Activities of sparfloxacin, azithromycin, temafloxacin, and rifapentine compared with that of clarithromycin against multiplication of Mycobacterium avium complex within human macrophages.

The activities of sparfloxacin, azithromycin, temafloxacin, and rifapentine against two virulent strains of the Mycobacterium avium complex isolated from patients with AIDS were evaluated in a model of intracellular infection and were compared with that of clarithromycin. Human monocyte-derived macrophages were infected with the M. avium complex at day 6 of culture. The intracellular CFU was counted 60 min after inoculation. The intracellular and supernatant CFU was counted on days 4 and 7 after inoculation. The concentrations used, which were equal to peak levels in serum, were 10 micrograms of rifapentine per ml (MICs for the two strains, 4 and 16 micrograms/ml), 4 micrograms of clarithromycin per ml (MICs, 8 and 4 micrograms/ml), 1 microgram of azithromycin per ml (MICs, 32 and 16 micrograms/ml), 4 micrograms of temafloxacin per ml (MICs, 2 and 16 micrograms/ml), and 1 microgram of sparfloxacin per ml (MICs, 0.5 and 2 micrograms/ml). Compared with controls on day 7 after inoculation, clarithromycin (P less than 0.001), sparfloxacin (P less than 0.001), and azithromycin (P less than 0.001 for the first strain, P less than 0.02 for the second) slowed intracellular replication. Rifapentine (P less than 0.001) and temafloxacin (P less than 0.001) slowed intracellular replication of the first strain but not of the second strain. Azithromycin plus sparfloxacin was as effective as sparfloxacin alone. In this macrophage model, sparfloxacin or clarithromycin (difference not significant) exhibited a better efficacy than rifapentine, azithromycin, or temafloxacin against intracellular M. avium complex infection.

Activities of clarithromycin, sulfisoxazole, and rifabutin against Mycobacterium avium complex multiplication within human macrophages.

The activities of clarithromycin, sulfisoxazole, and rifabutin against three virulent strains of Mycobacterium avium complex isolated from patients with acquired immunodeficiency syndrome were evaluated in a model of intracellular infection. Human monocyte-derived macrophages were infected at day 6 of culture with M. avium complex. Intracellular bacteria were counted 60 min after inoculation. Extra- and intracellular bacteria were counted at days 4 and 7 after inoculation. The concentrations used were 4 micrograms of clarithromycin per ml (MICs for the three strains, 4, 4, and 4 micrograms/ml), 50 micrograms of sulfisoxazole per ml (MICs, 50, 25, and 25 micrograms/ml), and 0.5 micrograms of rifabutin per ml (MICs, 2, 0.5, and 0.5 micrograms/ml). Compared with controls, clarithromycin and rifabutin slowed the intracellular replication of the three strains (at day 7 after inoculation, P was less than 0.01 for the first strain and less than 0.001 for the two others). Sulfisoxazole was ineffective against the three strains. Clarithromycin was as effective as rifabutin. Clarithromycin plus rifabutin was as effective as each single agent. Clarithromycin plus sulfisoxazole was as effective as clarithromycin alone.