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Si Palmer

Publications and source records attributed to Si Palmer.

7 recordsLinked to original sources
PubMed2006

Molecular analysis of human and bovine tubercle bacilli from a local setting in Nigeria.

To establish a molecular epidemiological baseline for the strains causing tuberculosis in Nigeria, a survey of isolates from humans and cattle was carried out. Spoligotyping and variable-number tandem-repeat analysis revealed that the majority of tuberculosis disease in humans in Ibadan, southwestern Nigeria, is caused by a single, closely related group of Mycobacterium tuberculosis strains. Using deletion typing, we show that approximately 13% of the disease in humans in this sample was caused by strains of Mycobacterium africanum and Mycobacterium bovis rather than M. tuberculosis. Molecular analysis of strains of M. bovis recovered from Nigerian cattle show that they form a group of closely related strains that show similarity to strains from neighboring Cameroon. Surprisingly, the strains of M. bovis recovered from humans do not match the molecular type of the cattle strains, and possible reasons for this are discussed. This is the first molecular analysis of M. tuberculosis complex strains circulating among humans and cattle in Nigeria, the results of which have significant implications for disease control.

Animals↗
PubMed2004

Genotypic analysis of Mycobacterium tuberculosis in Bangladesh and prevalence of the Beijing strain.

Genotypic analysis was performed on 48 Mycobacterium tuberculosis complex strains collected from a hospital in Dhaka city. Deletion analysis showed that the isolates were all M. tuberculosis; 13 of them were found to be of the "ancestral" type, while 35 were of the "modern" type, indicating that both endemic (ancestral type) and epidemic (modern type) strains cause tuberculosis in Bangladesh. Genotyping based on the spoligotype and variable-number tandem repeats (VNTR) of mycobacterial interspersed repetitive units (MIRU) was also done. A total of 34 strains (71%) were grouped by spoligotyping into nine different clusters; the largest comprised 15 isolates of the Beijing genotype, whereas the remaining eight clusters consisted of two to five isolates. MIRU-VNTR typing detected 32 different patterns among 44 tested strains, and the 15 Beijing strains were further discriminated by MIRU-VNTR typing (7 distinct patterns for the 15 isolates). These results indicate that MIRU-VNTR typing, along with spoligotyping and deletion analysis, can be used effectively for molecular epidemiological studies to determine ongoing transmission clusters; to our knowledge, this is the first report about the type of strains prevailing in Bangladesh.

Adult↗
PubMed2003

The population structure of Mycobacterium bovis in Great Britain: clonal expansion.

We have analyzed 11,500 isolates of Mycobacterium bovis (the cause of tuberculosis in cattle and other mammals) isolated in Great Britain (England, Wales and Scotland)] and characterized by spoligotype. Genetic exchange between cells is rare or absent in strains of the Mycobacterium tuberculosis complex so that, by using spoligotypes, it is possible to recognize "clones" with a recent common ancestor. The distribution of variable numbers of tandem repeats types in the most common clone in the data set is incompatible with random mutation and drift. The most plausible explanation is a series of "clonal expansions," and this interpretation is supported by the geographical distribution of different genotypes. We suggest that the clonal expansion of a genotype is caused either by the spread of a favorable mutation, together with all other genes present in the ancestral cell in which the mutation occurred, or by the invasion of a novel geographical region by a limited number of genotypes. A similar pattern is observed in M. tuberculosis (the main cause of tuberculosis in humans). The significance of clonal expansion in other bacteria that have recombination is discussed.

Bacterial Physiological Phenomena↗
PubMed2003

Genomic analysis of Mycobacterium tuberculosis complex strains used for production of purified protein derivative.

The genomes of the tuberculin production strains Mycobacterium bovis AN5 and Mycobacterium tuberculosis DT were compared to genome-sequenced tubercle bacilli by using DNA microarrays. Neither the AN5 nor DT strain suffered extensive gene deletions during in vitro passage. This suggests that bovine tuberculin made from M. bovis AN5 is suitable to detect infection with presently prevalent M. bovis strains.

Gene Deletion↗