We analyzed DNA polymorphisms in 455 Mycobacterium tuberculosis complex isolates from 455 patients to evaluate the biodiversity of tubercle bacilli in Ouest province, Cameroon. The phenotypic and genotypic identification methods gave concordant results for 99.5% of M. tuberculosis isolates (413 strains) and for 90% of Mycobacterium africanum isolates (41 strains). Mycobacterium bovis was isolated from only one patient. Analysis of regions of difference (RD4, RD9, and RD10) proved to be an accurate and rapid method of distinguishing between unusual members of the M. tuberculosis complex. Whereas M. africanum strains were the etiologic agent of tuberculosis in 56% of cases 3 decades ago, our results showed that these strains now account for just 9% of cases of tuberculosis. We identified a group of closely genetically related M. tuberculosis strains that are currently responsible for >40% of smear-positive pulmonary tuberculosis cases in this region of Cameroon. These strains shared a spoligotype lacking spacers 23, 24, and 25 and had highly related IS6110 ligation-mediated (LM) PCR patterns. They were designated the "Cameroon family." We did not find any significant association between tuberculosis-causing species or strain families and patient characteristics (sex, age, and human immunodeficiency virus status). A comparison of the spoligotypes of the Cameroon strains with an international spoligotype database (SpolDB3) containing 11,708 patterns from >90 countries, showed that the predominant spoligotype in Cameroon was limited to West African countries (Benin, Senegal, and Ivory Coast) and to the Caribbean area.In 1993, the World Health Organization declared tuberculosis (TB) a global emergency. One-third of the world's population is infected by Mycobacterium tuberculosis complex strains, the etiologic agents of TB. Although Ͻ10% of infected people actually develop active TB during their lifetimes, this represents 8 million new cases of TB each year, including 3.5 million (44%) cases of smear-positive pulmonary disease, leading to 1.9 million deaths per year (5, 6). Ninety-five percent of cases occur in developing countries, where the lack of proper health care systems leads to incomplete case and contact tracing, incomplete treatment, and an increase in drug resistance. Due to the powerful interaction between TB and human immunodeficiency virus (HIV) disease, together with the problems of poverty and malnutrition, the incidence of TB is increasing dramatically in sub-Saharan Africa (22).In Cameroon, a country with 15 million inhabitants, the incidence of TB in 2000 was estimated at Ͼ300 cases per 100,000 inhabitants in the last World Health Organization report (29), with an estimated 21,594 new sputum smear-positive cases. Although there is a paucity of information regarding the distribution of M. tuberculosis complex strains in Cameroon, one study performed 30 years ago (14) reported that 56% of cases of TB were due to Mycobacterium africanum strains in Ouest and Sud provinces, Cameroon.Several intervention s...

To assess the magnitude of the Buruli ulcer (BU) problem in Cameroon, we conducted a cross-sectional survey in the Nyong River basin and identified on clinical grounds a total of 436 cases of active or inactive BU (202 and 234, respectively). Swab specimens were taken from 162 active cases with ulcerative lesions and in 135 of these (83.3%) the clinical diagnosis was confirmed by the IS2404 polymerase chain reaction. Most lesions (93%) were located on the extremities, with lower limbs being twice as commonly involved as upper limbs. The age of patients with active BU ranged from 2 to 90 years with a median age of 14.5 years. Vaccination with bacilli Calmette-Guérin appeared to protect children against more severe forms of BU with multiple lesions. We conclude that in Cameroon BU is endemic, at least in the study area, and that a comprehensive control program for BU in Cameroon is urgently needed.

A preliminary investigation of the genetic biodiversity of Mycobacterium tuberculosis complex strains in Cameroon, a country with a high prevalence of tuberculosis, described a group of closely related M. tuberculosis strains (the Cameroon family) currently responsible for more than 40% of smear-positive pulmonary tuberculosis cases. Here, we used various molecular methods to study the genetic characteristics of this family of strains. Cameroon family M. tuberculosis strains (i) are part of the major genetic group 2 and lack the TbD1 region like other families of epidemic strains, (ii) lack spacers 23, 24, and 25 in their direct repeat ( Molecular epidemiology methods revolutionized the fields of research, prevention, and control of tuberculosis (TB), allowing the differentiation between strains, assessment of the overall diversity of Mycobacterium tuberculosis complex strains including differences by region and population, and measurement of the prevalence of endemic strains (28). However, few molecular epidemiological studies have been conducted in countries with a high incidence of TB. The available data suggest that families of closely related strains are common in these areas (12). The "Beijing family" is one of the most well-known families, highly prevalent in East Asia and widespread around the world (11).Molecular analysis based on several variable genomic regions is required for a good definition of strains belonging to different families. Restriction fragment length polymorphism (RFLP) analysis based on the insertion sequence IS6110 results in a unique genotype since both the number of copies of this genetic element and its positions in the genome are variable (25,26). Precise IS6110 insertion site mapping provides additional information on the fitness of the strain (1) given that IS6110 insertion can modify the expression of the gene involved. Another genetic element useful for characterizing tubercle bacilli is the direct repeat (DR) locus (13), a polymorphic insertion preferential locus (ipl) for IS6110. DR polymorphism can be analyzed by spoligotyping, a method involving PCR-reverse hybridization (14). The DR locus is likely to evolve more slowly than IS6110, making spoligotyping less adequate than IS6110-RFLP for discriminating strains but more convenient for investigating the biogeographic distribution of families of M. tuberculosis complex strains (32). Variable-number tandem repeats, named mycobacterial interspersed repetitive units (MIRU-VNTR), are another type of variable element in the M. tuberculosis complex genome showing extensive polymorphism (17) with a discrimination power close to that of IS6110-RFLP (6). Because of their stability, they can be used for a clear definition of families of tubercle bacilli as well.Strains of the M. tuberculosis complex exhibit very little genome sequence diversity except in repeat sequences. Consequently, insignificant and rare genome alterations inherited and maintained through long-term evolution can be of phylogenetic value. On the basis of polymorphi...

The sensitivity of culture in Bactec TM Plus Aerobic=F Ã culture vials of body¯uids from adult patients at a university hospital was compared with that of conventional culture methods, including enrichment in Schaedler broth. Previous antibiotic therapy was recorded at the time of sampling. Analysis of culture results took account of the clinical signi®cance of isolates and impact on therapy. Of 336 specimens evaluated, 81 (24%) yielded positive cultures, of which 50 cultures (15%) were considered to be clinically signi®cant (yielding 71 isolates) and 31 (9%) were considered contaminated. Of the 71 pathogens, 16 (23%) were isolated in the Bactec system only, whereas 13 (18%) grew in conventional media only; 12 of the latter were strict anaerobes. Among clinically signi®cant positive specimens, 19 (38%) were from patients receiving antibiotic therapy. In 27 cases (8% of all specimens and 54% of signi®cantly positive cultures), the isolation of a pathogen led to modi®cation of therapy. Overall, culture in the Bactec system showed higher sensitivity for the isolation of aerobic micro-organisms than Schaedler broth. Most of the difference was due to a better recovery of Streptococcaceae. Additional pathogens found only in resin-containing Bactec media led to 30% of all culture-in¯uenced modi®cations of empirical therapy. These data con®rm that culture of normally sterile body¯uids frequently yields results that are useful for guiding therapy. Although more costly than standard enrichment broth, the resin-containing Bactec Plus Aerobic=F Ã vial can be advantageous for culture of aerobic pathogens from these specimens, particularly in patients receiving antibiotic therapy.