Cameroon Family Research Articles

Genetic pattern of the ST 61 cluster of the Cameroon family among Mycobacterium tuberculosis complex strains collected during the CANTAM I project in Cameroon

Tuberculosis (TB) remains one of the most outstanding diseases in global health concern. It is caused by Mycobacterium tuberculosis Complex (MTBC) strains. ST 61, a cluster of the LAM10_CAM family has been shown to be the most prevalent cluster implicated in TB transmission in Cameroon. The present study is aimed at revealing the most discriminative loci applied to this cluster and investigating the genetic pattern in the ST 61 cluster clinical samples. This was a 12 month cross- sectional study that included 45 randomly selected clinical specimens previously collected during the CANTAM 1 project. Following DNA extraction, amplification of 12-locus Mycobacterial Interspersed Repetitive Unit-Variable Tandem Repeat (MIRU-VNTR) analysis (MIRU 40, ETR A, QUB 26, Mtub 39, QUB 4156, MIRU26, MIRU 31, MIRU 16, MIRU 02, MIRU 04, MIRU 23, and MIRU 27) PCR assay and gel electrophoresis were performed. The amplicon sizes, the allele assignations, the allelic pattern and the technic discriminative potential were determined using MIRU-VNTR plus web application and a dendogram was generated. 45% genetic pattern, and 66,6% clustering rate were reported. Overall, ETR A, MIRU 4, MIRU 16, MIRU 23, MIRU 27 revealed as the most discriminating loci applied to the cluster ST 61. The identification of the most discriminative locus ETRA, MIRU 4, MIRU 16, MIRU 23, and MIRU 27 applied to a precise cluster is a safe economic and time gain option to enhance the difference between strains at the cluster level.

Mycobacterium tuberculosis strain diversity and non Tuberculous Mycobacteria isolates in the West and Central Africa

Aims and objectives: The prevalence of pulmonary tuberculosis as well as Non Tuberculous Mycobacteria (NTM), has been on the increase worldwide. In order to improve the control of the disease, genotyping and drug susceptibility of Mycobacterium tuberculosis complex (MTBC) are important. This study sought to determine drug susceptibility and genetic diversity of MTBC as well as NTM in three West/Central African countries. Methods: A collection of 503 isolates (158 from Cameroon, 202 from Nigeria and 143 from Ghana) obtained from culture using either Lowenstein–Jensen medium, Middlebrook 7H9 Broth and/or Xpert MTB/RIF were included in the study and some isolates tested for drug susceptibility using the proportion method, BACTEC MGIT 960 or Line Probe Assay (LPA). Isolates were further subjected to IS6110 typing, large sequence polymorphisms, and spoligotyping. All IS6110-negative strains suspected as NTM were tested using hsp65 gene amplification, DNA sequencing and blast analysis. Results: The Cameroon family was the most prevalent genetic strain [128/202 (63.4%) in Nigeria, 54/150 (36%) in Cameroon and 27/119 (22.7%) in Ghana] and SIT 61 the largest cluster with 111/202 (55%) and 43/150 (27%) isolates in Nigeria and Cameroon respectively. Multidrug resistance (MDR) was observed in 29/202 (14.4%) cases in Nigeria, and HIV positivity [37/202 (18.3%) patients] was associated with rifampicin 9/37 (24.3%) resistance (p=0.012), as well as gender (p=0.009). In Cameroon, 13/147 (8.8 %) were resistant to rifampicin (RIF), with 6 (46.2%) of the 13 RIF resistant isolates associated with UgandaI sublineage (p=0.0007). Other sublineages such as Haarlem, Ghana, West African 1 were recorded in the three countries. NTMs isolates included M. colombiense, M. engbaekii, M. intracellulare strain, M. gordonae, M. fortuitum, M. paraense and Nocardia veteran. Conclusion: Neglected NTM timely diagnosis should be reinforced in the study area. Drug resistance in TB/HIV co-infected patients and its association with a sublineage calls for a surveillance strategy to curb its expansion in the west/central Africa.

Multidrug-resistant patients receiving treatment in Niger who are infected with M. tuberculosis Cameroon family convert faster in smear and culture than those with M. tuberculosis Ghana family

In this study, we analyzed the M. tuberculosis complex (MTBc) population structure among multidrug-resistant TB (MDR-TB) patients in Niger and tested whether the Cameroon family displayed a slower response to MDR-TB treatment. We genotyped baseline clinical isolates that had been collected from pulmonary MDR-TB patients recruited consecutively between 2008 and 2016 in Niger. Spoligotyping was used to analyze the genetic diversity of mycobacterial lineages, and Kaplan Meier's analysis to compare treatment outcomes. A total of 222 MTBc isolates were genotyped; 204 (91,9%) were identified as the Euro-American L4 lineage, with the Ghana family (106, 47,4%) and the Cameroon family (63, 28,4%) being predominant. Patients infected by Cameroon family isolates 61(96,8%) showed faster conversion (log-rank p < 0.01) than those infected with Ghana family isolates (91,5%), and were more likely to experience favorable outcome (adjusted odds ratio [aOR] 4.4; 95%CI 1.1–17.9]; p = 0.015). We found no association between MTBc families and second-line drug resistance profiles (p > 0.05). Our findings show that MDR-TB in Niger is caused by major spoligotypes of the Euro-American L4; with more rapid smear and culture conversion in patients infected with the Cameroon family. These first insights may alert clinicians that slow conversion may be associated with the type of infecting strain.

GENOTYPIC DIVERSITY AND DRUG SUSCEPTIBILITY PATTERNS AMONG M. TUBERCULOSIS COMPLEX ISOLATES RESPONSIBLE OF EXTRAPULMONARY TUBERCULOSIS IN CAMEROON FROM 2006–2015

BackgroundExtrapulmonary tuberculosis can cause major irreversible health complications if it is diagnosed late and not well treated. In Cameroon, it remains neglected with very few data concerning its different forms,...

Genetic Structure and Drug Susceptibility Patterns of Mycobacterium tuberculosis Complex Strains Responsible of Human Pulmonary Tuberculosis in the Major Rearing Region in Cameroon.

Background. Cameroon this last decade continues to present a low contribution of M. africanum and M. bovis in human tuberculosis (TB), while M. bovis was prevalent in cattle but all these pieces of information only concerned West and Center regions. Methods. We carried out the first study in Adamaoua, one of the most rearing regions of Cameroon, on the genetic structure and drug susceptibility of the MTBC strains isolated from newly diagnosed sputum smear-positive patients aged 15 years and above. For that purpose, spoligotyping, a modified 15 standard MIRU/VNTR loci typing, and the proportion method were used. Results. Four hundred and thirty-seven MTBC isolates were analyzed by spoligotyping. Of these, 423 were identified as M. tuberculosis, within the Cameroon family being dominant with 278 (65.7%) isolates; twelve (2.75%) isolates were classified as M. africanum and two as M. bovis. MIRU/VNTR typing of the most prevalent sublineage (SIT 61) suggested that this lineage is not a unique clone as thought earlier but could constitute a group of strains implicated to different pocket of TB transmission. Only M. tuberculosis sublineages were associated with antituberculosis drug resistance. Conclusion. These results showed the weak contribution of M. africanum and M. bovis to human active pulmonary tuberculosis in Cameroon even in the rearing region.

FAMILIES' RESPONSE TO AIDS: NEW INSIGHTS INTO PARENTAL ROLES IN FOSTERING HIV/AIDS KNOWLEDGE.

Worldwide, there is a consensus that parents must be involved in children's HIV/AIDS education. However, there is little evidence that speaks to this advocacy for improving adolescent health. This study developed and tested four hypotheses about (i) the relationship between parents' and adolescents' knowledge of HIV/AIDS transmission routes and prevention strategies conditional upon (ii) parents' gender, (iii) communication about sexuality, and (iv) the parent-adolescent education gap. The sample consisted of 306 parent-adolescent dyads from the 2002 Cameroon Family and Health Survey. Adolescents were aged 12-19 years. Overall, fifteen items about HIV/AIDS transmission routes and prevention strategies were analysed. Descriptive results showed that parents fared better than adolescents regardless of the AIDS fact considered. An exception was the correct use of condoms (parents 57% vs adolescents 61%). The generation gap probably explains this result: parents are more conservative, reluctant and distant from condoms compared with adolescents, who are more receptive and open to discussing sex with peers. Multivariate ordered logistic regressions showed a significant positive effect of parents' HIV/AIDS knowledge on adolescents' HIV/AIDS knowledge, thus supporting the main hypothesis of direct parental influences. Parent-adolescent communication about sexuality showed positive and significant effects on adolescents' HIV/AIDS knowledge, suggesting an 'enhancing effect' when combined with the effect of parents' HIV/AIDS knowledge. Against the background that parents in sub-Saharan Africa do not teach their children about sexuality, the study demonstrated that families can play an important role in HIV/AIDS education. These findings have major implications for HIV/AIDS interventions involving adolescents, parents or both, in fostering accurate HIV/AIDS knowledge among adolescents, which could lead to protective sexual behaviours.

Influences of family structure experiences on the risk of premarital sexual initiation during adolescence in Cameroon.

The link between family structure experiences and premarital sexual initiation in sub-Saharan African settings has been investigated using primarily the socialization perspective. This article tests additional hypotheses using the perspectives of change and duration of exposure. The analyses are based on time-dependent retrospective data on family living arrangements from a sample of 1182 individuals aged 12-24 years old, drawn from the Cameroon Family and Health Survey. From the socialization perspective for both females and males: living without both biological parents does not necessarily increase the probability of premarital sexual initiation during adolescence; the timing of family structure experiences is an important factor to consider in life course transitions; and other relatives play a protective role during adolescence, especially among females living in mother-only families. Findings also provide some support for the instability and change hypothesis as well as for the duration of exposure conjecture: a change from other family structure types to a both biological parents structure between age 6 and age 12 (change perspective) and living with the biological mother only at all the time (duration of exposure perspective) are associated with lower risks of premarital sexual initiation during adolescence among females. Our results have implications for preventing risky sexual behaviours during adolescence.

Mycobacterium tuberculosisis the causative agent of tuberculosis in the southern ecological zones of Cameroon, as shown by genetic analysis

BackgroundTuberculosis (TB) is a major cause of mortality and suffering worldwide, with over 95% of TB deaths occurring in low- and middle-income countries. In recent years, molecular typing methods have been widely used in epidemiological studies to aid the control of TB, but this usage has not been the case with many African countries, including Cameroon. The aims of the present investigation were to identify and evaluate the diversity of the Mycobacterium tuberculosis complex (MTBC) isolates circulating in two ecological zones of Cameroon, seven years after the last studies in the West Region, and after the re-organization of the National TB Control Program (NTBCP). These were expected to shed light also on the transmission of TB in the country. The study was conducted from February to July 2009. During this period, 169 patients with symptomatic disease and with sputum cultures that were positive for MTBC were randomly selected for the study from amongst 964 suspected patients in the savannah mosaic zone (West and North West regions) and the tropical rainforest zone (Central region). After culture and diagnosis, DNA was extracted from each of the MTBC isolates and transported to the BecA-ILRI Hub in Nairobi, Kenya for molecular analysis.MethodsGenetic characterization was done by mycobacterial interspersed repetitive unit–variable number tandem repeat typing (MIRU-VNTR) and Spoligotyping.ResultsMolecular analysis showed that all TB cases reported in this study were caused by infections with Mycobacterium tuberculosis (98.8%) and Mycobacterium africanum (M. africanum) (1.2%) respectively. We did not detect any M. bovis. Comparative analyses using spoligotyping revealed that the majority of isolates belong to major clades of M. tuberculosis: Haarlem (7.6%), Latin American-Mediterranean (34.4%) and T clade (26.7%); the remaining isolates (31.3%) where distributed among the minor clades. The predominant group of isolates (34.4%) corresponded to spoligotype 61, previously described as the “Cameroon family. Further analysis based on MIRU-VNTR profiles had greater resolving power than spoligotyping and defined additional genotypes in the same spoligotype cluster.ConclusionThe molecular characterization of MTBC strains from humans in two ecological regions of Cameroon has shown that M. tuberculosis sensu stricto is the predominant agent of TB cases in the zones. Three decades ago, TB was reported to be caused by M. africanum in 56.0% of cases. The present findings are consistent with a major shift in the prevalence of M. tuberculosis in Cameroon.

Effects of parenting practices on sexual risk-taking among young people in Cameroon

BackgroundThere is scanty evidence regarding the impact of parenting practices on young people’s sexual risk-taking in sub-Saharan Africa. Moreover, the extent to which such practices have enduring consequences on adolescents and young adults is little documented. This study uses repeated measures of parent–child relationships, parental monitoring, and parent–child communication about sexual matters to shed some light in these two areas.MethodsThe analysis is based on time-dependent retrospective data on parenting practices which were retrieved from the Cameroon Family and Health Survey (CFHS). The study sample includes 447 sexually active and unmarried individuals aged 15–24 years old. Correlation analysis and multivariate logistic regressions are used.ResultsYoung males and females reported high levels of parental monitoring, moderate quality of parent–child relationships and low levels of parent–child communication on sexual matters. This study substantiates that the higher the quality of parent–child relationships, the lower the odds of young males having multiple sexual partners (0.63, p < 0.05), and the lower the odds of young females being sexually active (0.52, p < 0.10) or of having multiple sexual partners (0.64, p < 0.10) or of having occasional sexual partners (0.51, p < 0.05). Living with the biological father only was associated with higher odds of having multiple sexual partners (3.21, p < 0.10) and higher odds of occasional concurrent sexual partners (3.26, p < 0.10) among young males. Compared with their out-of-school counterparts, young males still enrolled in school were less likely to be sexually active in the last 12 months (0.33, p < 0.05) and less likely to have occasional concurrent sexual partners (0.57, p < 0.10), whereas young females still enrolled in school were more likely to be sexually active (2.25, p < 0.10) and less likely to use contraceptive consistently (0.36, p < 0.001).ConclusionsReproductive health programs and interventions for preventing young people’s risky sexual behaviors in sub-Saharan African settings must take into account the protective effects of parent–child relationships and the significance of parental monitoring over time.

Timing of Premarital Intercourse in Bandjoun (West Cameroon)

This article examined the effects of family environment on the risks of premarital intercourse for male and female youth. Previous research in sub-Saharan Africa (SSA) on the linkages between family structures and sexual debut mainly utilized cross-sectional data. In a sample drawn from Cameroon Family and Health Survey ( N = 2,166), descriptive and multivariate results showed that youth who resided in nuclear two-parent families, those who reported higher levels of parental monitoring and higher quality of parent–child relationships during childhood and/or adolescence, had significantly lower rates of premarital intercourse. Polygynous families, parent–child communication, orphanhood, and change in family structure were significantly associated with higher rates of premarital intercourse. Programmatic implications for reproductive health interventions in SSA are discussed.

Population Dynamics of Tuberculous Bacilli in Cameroon as Assessed by Spoligotyping

Genetic assessment by spoligotyping of 565 Mycobacterium tuberculosis complex strains collected from the Western Region of Cameroon between 2004 and 2005 has confirmed the establishment of the "Cameroon family" as the leading cause of tuberculosis in 45.9% of cases and evidenced the rapid quasi extinction of Mycobacterium africanum, isolated in 3.3% of tuberculosis cases.

Fostering accurate HIV/AIDS knowledge among unmarried youths in Cameroon: do family environment and peers matter?

BackgroundThe last three decades have seen a series of HIV interventions in sub-Saharan Africa. However, youths still have a mixture of correct and incorrect HIV/AIDS knowledge of transmission routes and prevention strategies. Previous studies have identified parents and peers as the most important socializing agents for youths. This paper assesses the relationships between family structure, family/peer communication about sexuality and accurate knowledge of transmission routes and prevention strategies.MethodsData were drawn from the Cameroon Family Life and Health Survey (CFHS) conducted in 2002. The CFHS collected information on a representative sample of 4 950 people aged 10 years and over nested within 1 765 selected households from the 75 localities forming the administrative prefecture of Bandjoun, using detailed questionnaires about family, HIV/AIDS/STDs knowledge, sexual behaviors, contraception, health, media exposure, household assets and neighborhood characteristics. The survey cooperation rates were high (97%). For the purpose of this study, a sub-sample of 2 028 unmarried youths aged 12 - 29 years was utilized.ResultsOverall, 42% of respondents reported accurate knowledge of documented HIV transmission routes whereas 21% of them had inaccurate knowledge such as AIDS can be transmitted through mosquito bites or casual contact with an infected person. Only 9% of respondents were knowledgeable about all HIV prevention strategies. Multivariate analyses showed that family structure, communication with parents/guardians and peers about sexual topics were significantly associated with accurate HIV knowledge. Additionally, age, education, sexual experience and migration had significant effects on accurate knowledge. Finally, living in poor households and disadvantaged neighborhoods significantly increased inaccurate knowledge of HIV transmission modes and prevention strategies.ConclusionsThis paper evidenced the limited effects of HIV interventions/programmes in sub-Saharan Africa. Indeed, few respondents reported accurate knowledge about HIV transmission routes and prevention strategies. Findings showed that the role of family environment as source of accurate HIV knowledge transmission routes and prevention strategies is of paramount significance; however, families have been poorly integrated in the design and implementation of the first generation of HIV interventions. There is an urgent need that policymakers work together with families to improve the efficiency of these interventions. Peer influences is likely controversial because of the double positive effect of peer-to-peer communication on both accurate and inaccurate knowledge of HIV transmission routes.

The Guinea-Bissau Family of Mycobacterium tuberculosis Complex Revisited

The Guinea-Bissau family of strains is a unique group of the Mycobacterium tuberculosis complex that, although genotypically closely related, phenotypically demonstrates considerable heterogeneity. We have investigated 414 M. tuberculosis complex strains collected in Guinea-Bissau between 1989 and 2008 in order to further characterize the Guinea-Bissau family of strains. To determine the strain lineages present in the study sample, binary outcomes of spoligotyping were compared with spoligotypes existing in the international database SITVIT2. The major circulating M. tuberculosis clades ranked in the following order: AFRI (n = 195, 47.10%), Latin-American-Mediterranean (LAM) (n = 75, 18.12%), ill-defined T clade (n = 53, 12.8%), Haarlem (n = 37, 8.85%), East-African-Indian (EAI) (n = 25, 6.04%), Unknown (n = 12, 2.87%), Beijing (n = 7, 1.68%), X clade (n = 4, 0.96%), Manu (n = 4, 0.97%), CAS (n = 2, 0.48%). Two strains of the LAM clade isolated in 2007 belonged to the Cameroon family (SIT61). All AFRI isolates except one belonged to the Guinea-Bissau family, i.e. they have an AFRI_1 spoligotype pattern, they have a distinct RFLP pattern with low numbers of IS6110 insertions, and they lack the regions of difference RD7, RD8, RD9 and RD10, RD701 and RD702. This profile classifies the Guinea-Bissau family, irrespective of phenotypic biovar, as part of the M. africanum West African 2 lineage, or the AFRI_1 sublineage according to the spoligtyping nomenclature. Guinea-Bissau family strains display a variation of biochemical traits classically used to differentiate M. tuberculosis from M. bovis. Yet, the differential expression of these biochemical traits was not related to any genes so far investigated (narGHJI and pncA). Guinea-Bissau has the highest prevalence of M. africanum recorded in the African continent, and the Guinea-Bissau family shows a high phylogeographical specificity for Western Africa, with Guinea-Bissau being the epicenter. Trends over time however indicate that this family of strains is waning in most parts of Western Africa, including Guinea-Bissau (p = 0.048).

First Molecular Epidemiology Study ofMycobacterium tuberculosisin Burkina Faso

We conducted a molecular epidemiology study on 120 Mycobacterium tuberculosis isolates from patients presenting pulmonary tuberculosis (TB) in Burkina Faso. Classical antibiogram studies and genetic characterization, using mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) typing and spoligotyping, were applied after culture. Molecular analysis of specific signatures showed that all TB cases reported in this study were caused by M. tuberculosis and identified no Mycobacterium bovis or Mycobacterium africanum isolates. This result is unexpected, as M. africanum strains were reportedly the etiologic agent in 20% of TB cases 2 decades ago. The comparison of spoligotypes from Burkina Faso with an international spoligotype database (SpolDB4) showed that the majority of isolates belong to major clades of M. tuberculosis (Haarlem, 9%; Latin American-Mediterranean, 30%; and T, 20%). The predominant group of isolates (30%) corresponds to spoligotype 61, described in Cameroon as the "Cameroon family." In Burkina Faso, as in Cameroon, this family could be associated with recent transmission of TB, suggesting a recent expansion in West Africa. Our data suggest a low level of primary drug resistance that may be a positive result of the Directly Observed Therapy Shortcourse program. Besides, based on spoligotyping plus MIRU-VNTR, data showed a high number of clusters in our sample, suggesting a high level of recent TB transmission in Burkina Faso. Nevertheless, an important genetic polymorphism was observed in this country, reflecting an endemicity situation where the control of TB would have less impact in the main towns.

Molecular characterization and drug resistance testing of Mycobacterium tuberculosis isolates from Chad.

The molecular characterizations of the first 40 Mycobacterium tuberculosis isolates from Chad revealed a high proportion of isolates of the Cameroon family (33%), of which one isolate showed a monodrug resistance. In total, 9/33 (27%) isolates were resistant to isoniazid. The implications of these findings are discussed.

Molecular Characteristics of Strains of the Cameroon Family, the Major Group of Mycobacterium tuberculosis in a Country with a High Prevalence of Tuberculosis

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 (DR) region, (iii) have an identical number of repeats in 8 of 12 variable-number tandem repeats of mycobacterial interspersed repetitive unit (MIRU-VNTR) loci, (iv) have similar IS6110-restriction fragment length polymorphism (RFLP) multiband patterns (10 to 15 copies) with seven common IS6110 bands, (v) do not have an IS6110 element in their DR locus, and (vi) have four IS6110 elements in open reading frames (adenylate cyclase, phospholipase C, moeY, and ATP binding genes). Analysis by spoligotyping, MIRU-VNTR, and IS6110-RFLP typing methods revealed differences not observed in previous studies; polymorphism as assessed by MIRU-VNTR typing was lower than suggested by spoligotyping, and in rare cases, strains with identical IS6110-RFLP patterns had spoligotypes differing by as much as 15 spacers. Our findings confirm the recent expansion of this family in Cameroon and indicate that the interpretation of molecular typing results has to be adapted to the characteristics of the strain population within each setting. The knowledge of this particular genotype, with its large involvement in tuberculosis in Cameroon, allows greater refinement of tuberculosis transmission studies by interpreting data in the context of this geographic area.

Genetic biodiversity of Mycobacterium tuberculosis complex strains from patients with pulmonary tuberculosis in Cameroon.

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.