PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-6 (6)
 

Clipboard (0)
None

Select a Filter Below

Journals
Year of Publication
Document Types
1.  A non-sense mutation in the putative anti-mutator gene ada/alkA of Mycobacterium tuberculosis and M. bovis isolates suggests convergent evolution 
BMC Microbiology  2007;7:39.
Background
Previous studies have suggested that variations in DNA repair genes of W-Beijing strains may have led to transient mutator phenotypes which in turn may have contributed to host adaptation of this strain family. Single nucleotide polymorphism (SNP) in the DNA repair gene mutT1 was identified in MDR-prone strains from the Central African Republic. A Mycobacteriumtuberculosis H37Rv mutant inactivated in two DNA repair genes, namely ada/alkA and ogt, was shown to display a hypermutator phenotype. We then looked for polymorphisms in these genes in Central African Republic strains (CAR).
Results
In this study, 55 MDR and 194 non-MDR strains were analyzed. Variations in DNA repair genes ada/alkA and ogt were identified. Among them, by comparison to M. tuberculosis published sequences, we found a non-sense variation in ada/alkA gene which was also observed in M. bovis AF2122 strain. SNPs that are present in the adjacent regions to the amber variation are different in M. bovis and in M. tuberculosis strain.
Conclusion
An Amber codon was found in the ada/alkA locus of clustered M. tuberculosis isolates and in M. bovis strain AF2122. This is likely due to convergent evolution because SNP differences between strains are incompatible with horizontal transfer of an entire gene. This suggests that such a variation may confer a selective advantage and be implicated in hypermutator phenotype expression, which in turn contributes to adaptation to environmental changes.
doi:10.1186/1471-2180-7-39
PMCID: PMC1891112  PMID: 17506895
2.  Poor Performance of a Novel Serological Test for Diagnosis of Pulmonary Tuberculosis in Bangui, Central African Republic 
Clinical and Vaccine Immunology  2006;13(6):702-703.
We assessed the performance of a serological test for tuberculosis (SDHO Laboratories Inc., Canada) in our setting. Among 68 of 99 suspected pulmonary tuberculosis patients who were scored as having tuberculosis on the basis of Mycobacterium tuberculosis-positive culture, the sensitivity of the serological test was lower than that of sputum smear microscopic examination (20.6% versus 80.9%, respectively; P < 0.000001).
doi:10.1128/CDLI.00194-05
PMCID: PMC1489549  PMID: 16760330
3.  Multidrug-resistant Mycobacterium tuberculosis, Bangui, Central African Republic 
Emerging Infectious Diseases  2006;12(9):1454-1456.
We investigated multidrug-resistant (MDR) Mycobacterium tuberculosis strains in Bangui, Central African Republic. We found 39.6% with the same spoligotype and synonymous single nucleotide polymorphism in the mutT1 gene. However, strains had different rpoB mutations responsible for rifampin resistance. MDR strains in Bangui may emerge preferentially from a single, MDR-prone family.
doi:10.3201/eid1209.060361
PMCID: PMC3298286  PMID: 17073103
Tuberculosis; Antibiotic resistance; Molecular epidemiology; dispatch
4.  Human Herpesvirus 8 Serological Markers and Viral Load in Patients with AIDS-Associated Kaposi's Sarcoma in Central African Republic 
Journal of Clinical Microbiology  2005;43(9):4840-4843.
Epidemic Kaposi's sarcoma (KS) is one of the most frequent types of cancer in several African countries; however, very few data are available on human herpesvirus 8 (HHV-8) markers in KS patients from Central Africa. In a series of 36 AIDS-KS cases from Central African Republic, we showed, using a real-time PCR quantitative assay, the high frequency (82%) of detectable HHV-8 DNA in peripheral blood mononuclear cells (PBMCs). We also found that the level of antibodies directed against lytic or latent HHV-8 antigens is not correlated to the amount of HHV-8 viral load in the PBMCs, and finally, we demonstrated a much higher viral load in tumoral skin lesions (6.07 log copies/μg DNA) than in unaffected skin (2.93 log copies/μg DNA) or in PBMCs (2.55 log copies/μg DNA).
doi:10.1128/JCM.43.9.4840-4843.2005
PMCID: PMC1234088  PMID: 16145154
5.  Snapshot of Moving and Expanding Clones of Mycobacterium tuberculosis and Their Global Distribution Assessed by Spoligotyping in an International Study†  
Journal of Clinical Microbiology  2003;41(5):1963-1970.
The present update on the global distribution of Mycobacterium tuberculosis complex spoligotypes provides both the octal and binary descriptions of the spoligotypes for M. tuberculosis complex, including Mycobacterium bovis, from >90 countries (13,008 patterns grouped into 813 shared types containing 11,708 isolates and 1,300 orphan patterns). A number of potential indices were developed to summarize the information on the biogeographical specificity of a given shared type, as well as its geographical spreading (matching code and spreading index, respectively). To facilitate the analysis of hundreds of spoligotypes each made up of a binary succession of 43 bits of information, a number of major and minor visual rules were also defined. A total of six major rules (A to F) with the precise description of the extra missing spacers (minor rules) were used to define 36 major clades (or families) of M. tuberculosis. Some major clades identified were the East African-Indian (EAI) clade, the Beijing clade, the Haarlem clade, the Latin American and Mediterranean (LAM) clade, the Central Asian (CAS) clade, a European clade of IS6110 low banders (X; highly prevalent in the United States and United Kingdom), and a widespread yet poorly defined clade (T). When the visual rules defined above were used for an automated labeling of the 813 shared types to define nine superfamilies of strains (Mycobacterium africanum, Beijing, M. bovis, EAI, CAS, T, Haarlem, X, and LAM), 96.9% of the shared types received a label, showing the potential for automated labeling of M. tuberculosis families in well-defined phylogeographical families. Intercontinental matches of shared types among eight continents and subcontinents (Africa, North America, Central America, South America, Europe, the Middle East and Central Asia, and the Far East) are analyzed and discussed.
doi:10.1128/JCM.41.5.1963-1970.2003
PMCID: PMC154710  PMID: 12734235
6.  Global Distribution of Mycobacterium tuberculosis Spoligotypes 
Emerging Infectious Diseases  2002;8(11):1347-1349.
We present a short summary of recent observations on the global distribution of the major clades of the Mycobacterium tuberculosis complex, the causative agent of tuberculosis. This global distribution was defined by data-mining of an international spoligotyping database, SpolDB3. This database contains 11,708 patterns from as many clinical isolates originating from more than 90 countries. The 11,708 spoligotypes were clustered into 813 shared types. A total of 1,300 orphan patterns (clinical isolates showing a unique spoligotype) were also detected.
doi:10.3201/eid0811.020125
PMCID: PMC2738532  PMID: 12453368
Mycobacterium tuberculosis; spoligotyping

Results 1-6 (6)