Clinical characteristics of the smooth tubercle bacilli 'Mycobacterium canettii' infection suggest the existence of an environmental reservoir.

Over a 3-year follow-up, 30 out of the 318 unique Mycobacterium tuberculosis complex isolates recovered in the Republic of Djibouti had a smooth-type morphology and were Niacine-negative, the characteristics of 'Mycobacterium canettii' strains. Unlike M. tuberculosis, 'M. canettii' grew on nutrient-poor media at 30°C, and possessed characteristic lipids. They were isolated from respiratory and extra-respiratory sites from patients with typical forms of tuberculosis. Most cases resolved with antibiotic therapy but in two human immunodeficiency virus-positive patients 'M. canettii' infection led to septicaemia and death. No cases of human-to-human transmission were observed. The proportion of tuberculosis cases caused by 'M. canettii' was higher among French patients than among Djiboutian patients. Patients with 'M. canettii' were significantly younger than those with tuberculosis caused by other M. tuberculosis complex strains. Smooth tubercle bacilli could be misidentified as non-tuberculous mycobacteria and appear to be limited to the Horn of Africa. Their characteristics are consistent with the existence of non-human sources of infection.

[Comparison of annual risk for tuberculosis infection (1994-2001) in school children in Djibouti: methodological limitations and epidemiological value in a hyperendemic context]. / Comparaison du risque annuel d'infection tuberculeuse (1994-2001) auprès d'enfants scolarisés à Djibouti: limites méthodologiques et intérêt épidémiologique dans un contexte hyperendémique.

The purpose of this report was to describe a tuberculin survey conducted in 2001 to assess the trend in the annual risk for tuberculosis infection in Djibouti and compare resulting data with those obtained in a previous survey conducted in 1994. In 2001 cluster sampling allowed selection of 5599 school children between the ages of 6 and 10 years including 31.2% (1747/5599) without BCG vaccination scar. In this sample the annual risk of infection (ARI) estimated using cutoff points of 6 mm, 10 mm, and 14 mm corrected by a factor of 1/0.82 and a mode value (18 mm) determined according to the "mirror" method were 4.67%, 3.64%, 3.19% and 2.66% respectively. The distribution of positive tuberculin skin reaction size was significantly different from the normal law. In 1994 a total of 5257 children were selected using the same method. The distribution of positive reactions was not significantly different from the gaussian distribution and 28.6% (1505/5257) did not have a BCG scar. The ARI estimated using cutoff points of 6 mm, 10 mm, and 14 mm corrected by a factor of 1/0.82 and a mode value (17 mm) determined according to the "mirror" method were 2.68%, 2.52%, 2.75% and 3.32 respectively. Tuberculin skin reaction size among positive skin test reactors was correlated with the presence of a BCG scar, and its mean was significantly higher among children with BCG scar. The proportion of positive skin test reactors was also higher in the BCG scar group regardless of the cutoff point selected. Comparison of prevalence rates and ARI values did not allow any clear conclusion to be drawn, mainly because of a drastic difference in the positive reaction distribution profiles between the two studies. The distribution of the skin test reaction's size 1994 study could be modelized by a gaussian distribution while it could not in 2001. A partial explanation for the positive reaction distribution observed in the 2001 study might be the existence of cross-reactions with environmental mycobacteria.

Prevalence and trends of infection with Mycobacterium tuberculosis in Djibouti, testing an alternative method.

SETTING: Djibouti, 1994 and 2001. OBJECTIVE: To estimate the prevalence of tuberculosis (TB) and average annual risk of TB infection (ARTI) and trends, and to test a new method for calculations. METHODS: Tuberculin surveys among schoolchildren and sputum smear-positive TB patients. Prevalence of infection was calculated using cut-off points, the mirror image technique, mixture analysis, and a new method based on the operating characteristics of the tuberculin test. Test sensitivity was derived from tuberculin reactions among TB patients and test specificity from a comparison of reaction size distributions among children with and without a BCG scar. RESULTS: The ARTI was estimated to lie between 2.6% and 3.1%, with no significant changes between 1994 and 2001. The close match of the distributions between children tested in 1994 and patients justifies the utilisation of the latter to determine test sensitivity. This new method gave very consistent estimates of prevalence of infection for any induration for values between 15 and 20 mm. Specificity was successfully determined for 1994, but not for 2001. Mixture analysis confirmed the estimates obtained with the new method. CONCLUSION: Djibouti has a high ARTI, and no apparent change over the observation time was found. Using operating test characteristics to estimate prevalence of infection looks promising.

Clinical evaluation of the gen-probe amplified mycobacterium tuberculosis direct test for rapid diagnosis of tuberculosis lymphadenitis.

This prospective study evaluated the performance of the Amplified Mycobacterium Tuberculosis Direct Test (MTD) for the diagnosis of lymph node tuberculosis in Djibouti, Republic of Djibouti. Of 197 specimens sampled from 153 patients, 123 were from 95 tuberculous patients. The sensitivity and specificity of MTD were 93 and 100%, respectively. The sensitivity of culture was 89%.

Decentralisation of directly observed treatment in a large African city: evaluation of the experience of Djibouti.

SETTING: Decentralisation of directly observed treatment (DOT) for tuberculosis patients in three public centres in Djibouti city from April 2000. OBJECTIVES: To evaluate decentralisation based on the success rate by site of treatment and according to certain critical variables. METHODS: Comparative evaluation of the success rate of smear-positive patients followed in all treatment centres from 1 May 2000 to 31 March 2001. RESULTS: The success rate was 58% for the main centre, Centre Paul Faure, and 81% for all the peripheral centres together (P < 10.6). It was 80% for the three new centres and 85% for the established centres (P > 0.05). Age under 20 years, female sex and treatment centre were factors linked to success. After stratification, sex was shown to be the confounding variable. Multivariate analysis shows that non-Djibouti nationality is related to treatment success (P = 0.02). In the groups of established and new centres, there is an inverse linear relationship between success rate and workload, with greater capacity in the established centres. CONCLUSIONS: Urban decentralisation of DOT increases the chances of treatment success among smear-positive patients. Another centre for supervised treatment needs to be created in one of the public health centres in Djibouti city.

[Epidemiology of resistance to antituberculosis drugs in Mycobacterium tuberculosis complex strains isolated from adenopathies in Djibouti. Prospective study carried out in 1999]. / Epidemiologie de la resistance aux antituberculeux des souches du complexe Mycobacterium tuberculosis isolees d'adenopathies a Djibouti. Etude prospective realisee en 1999.

Tuberculosis is a major cause of death in the Republic of Djibouti. Tuberculous lymphadenitis represents about 25% of the clinical forms of tuberculosis in this country. Between January 1999 and April 1999, 196 lymph node specimens were consecutively collected from 153 patients living in Djibouti. Testing of susceptibility to the major anti-tuberculosis drugs was performed by the proportion method. Growth of Mycobacterium tuberculosis complex strains was obtained from specimens of 85 patients including 9 with prior treatment. Strains were identified as Mycobacterium tuberculosis in 78 cases, Mycobacterium canetti in 3, Mycobacterium africanum in 3, and Mycobacterium bovis in 1. Prevalence of HIV infection was 15%. Assessment of primary resistance demonstrated that the overall resistance rate, i.e., resistance to 1 or more drugs, was 18 (21.2%). Results showed resistance to isoniazid (H) in 6 cases (7.1%), rifampicin (R) in 3 (3.5%), ethambutol (E) in 1 (1.2%), streptomycin (S) in 13 (15.3%) and pyrazinamide (Z) in 1 (1.2%). Multidrug resistance (MDR) was found in 2 cases (2.4%). Assessment of acquired resistance demonstrated resistance to H in 4 cases (44%), R in 2 (22%), S in 2 (22%), E in 0, Z in 0 and MDR in 1 (11%). These findings were not significantly different from data obtained from sputum samples analysed between 1997 and 2000 or from those described in a study conducted in 1985.