ABSTRACT
Helicobacter pylori is the pathogenic bacterium linked to gastric and duodenal ulcers and gastric carcinoma. Genomic diversity of the organism has enabled new insights into its population biology through comparative genomics. genoBASE pylori is an online databank of several virulence-linked and phylogenetic markers of H. pylori strains obtained from different human populations. This knowledgebase is built upon a relational database management system which is connected to visualize the presence of known, pathogenicity markers such as the co-ordinates within the cag pathogenicity island (cagPAI), the cagA gene and motifs surrounding it, the vacA allotypes and the oipA gene frame status, together with genotypic details in the form of DNA profiling traces and candidate gene sequences for individual strains. This flexible search tool allows inter-laboratory comparison of DNA fingerprinting data in the form of fluorescent amplified fragment length polymorphism (FAFLP), enterobacterial repetitive intergenic consensus (ERIC) and repetitive extragenic palindromic (REP) signature profiles. Besides this, the database also displays diversity of strains based on nucleotide sequences of several house keeping genes and two membrane proteins. Being the first of its kind, genoBASE pylori is expected to be a helpful online tool in strengthening the concept of 'geographic genomics' and will be useful to molecular epidemiologists, clinical laboratory scientists and those interested in diagnostic development for H. pylori. The database can be accessed through its website (http://www.cdfd.org.in/amplibase/HP).
Subject(s)
Computational Biology/methods , Databases, Nucleic Acid , Helicobacter pylori/genetics , Software , Stomach/microbiology , Genetic Markers , Genotype , Humans , User-Computer InterfaceABSTRACT
BACKGROUND: Genomic diversity of H. pylori from many different human populations is largely unknown. We compared genomes of 65 H. pylori strains from Nottingham, England. Molecular analysis was carried out to identify rearrangements within and outside the cag-pathogenicity-island (cag PAI) and DNA sequence divergence in candidate genes. Phylogenetic analysis was carried out based on various high-resolution genotyping techniques. RESULTS: Analyses of virulence genes (cagT, cagE, cagA, vacA, iceA, oipA and babB) revealed that H. pylori strains from England are genetically distinct from strains obtained from other countries. The toxigenic vacA s1m1 genotype was found to be less common and the plasticity region cluster was found to be disrupted in all the isolates. English isolates showed a predominance of iceA1 alleles and a functional proinflammatory oipA gene. The English H. pylori gene pool revealed several Asian/oriental features. This included the predominance of cagA - glr (cagA right junction) motif types III and II (up to 42%), presence of vacA m1c alleles and phylogenetic affinity towards East Asian / Amerindian gene pools based on fluorescent amplified fragment length polymorphism (FAFLP) analysis and glmM sequence analysis. CONCLUSION: Overall, our results demonstrated genetic affinities of H. pylori in England with both European and the Asian gene pools and some distinctive genetic features of virulence genes that may have evolved in this important European population.
Subject(s)
Genomics , Helicobacter Infections/microbiology , Helicobacter pylori/genetics , Helicobacter pylori/isolation & purification , Stomach Ulcer/microbiology , Bacterial Proteins/genetics , England/epidemiology , Genetic Variation , Genome, Bacterial , Helicobacter Infections/epidemiology , Humans , Phylogeny , Stomach Ulcer/epidemiology , Virulence FactorsABSTRACT
AmpliBASE MT is an online databank of high-resolution DNA fingerprints representing fluorescent amplified fragment length polymorphism (FAFLP) profiles or amplitypes developed for the Mycobacterium tuberculosis complex strains from 48 different countries. AmpliBASE MT is based on a relational database management system that is hyperlinked to visualize genotyping results in the form of DNA fingerprint images for individual strains. A flexible search system based on systematic comparisons of fragment sizes in base pairs allows inter-laboratory comparison of FAFLP profiles. Besides this, the database also displays previously published data on IS6110 profiles, spoligotypes, MIRU-VNTRs and large sequence polymorphisms along with the FAFLP records that will give the overall comparisons. Being the first of its kind, AmpliBASE MT is expected to be a very helpful tool in strengthening the concept of 'geographic genomics' and will be very helpful to molecular epidemiologists and those interested in diagnostic development for tuberculosis.
Subject(s)
DNA Fingerprinting/methods , Database Management Systems , Databases, Nucleic Acid , Gene Expression Profiling/methods , Information Storage and Retrieval/methods , Mycobacterium tuberculosis/genetics , User-Computer Interface , Genetic Variation/genetics , Internet , Phenotype , SoftwareABSTRACT
Genome sequence-based fluorescent amplified-fragment length polymorphism (FAFLP) analysis was investigated for fingerprinting and subtyping 42 multiple drug resistant (MDR) isolates of Pseudomonas aeruginosa from post-surgical endophthalmitis. The FAFLP profiles derived from EcoRI/MseI restricted fragments differentiated clinical isolates and were found to be extremely reproducible. Seventeen different amplification patterns (amplitypes) were observed for all the 42 isolates from 11 different patients. Also, we were able to genotype the isolates based on the differential amplification of a total of 31 FAFLP markers representing genomic fragments from the P. aeruginosa chromosome. This data appears to provide clues to the genetic diversity of endopthalmitis associated strains and could be converted into digitised fingerprints suitable for electronic manipulations and archiving.
