Escherichia coli phylogenetic B2 subgroups in the infant gut microbiota: predominance of uropathogenic lineages in Swedish infants and enteropathogenic lineages in Pakistani infants
Project description:Escherichia coli segregates into phylogenetic groups, with group B2 containing both extraintestinal pathogenic E. coli (ExPEC) and enteropathogenic E. coli (EPEC) strains. Ten main B2 subgroups (subgroups I to X)/sequence type complexes (STcs), as well as EPEC lineages, have been identified. In the current study, we characterized ExPEC and EPEC strains of E. coli B2 phylogenetic subgroups/STcs that colonize Swedish and Pakistani infants. Gut commensal E. coli B2 strains, 120 from Swedish infants (n = 87) and 19 from Pakistani infants (n = 12), were assigned to B2 subgroups. Carriage of the bundle-forming pili and intimin adhesin was examined in the EPEC lineages. The ExPEC virulence markers and the time of persistence of the strains in the microbiota were previously determined. In total, 84% of the Swedish strains and 47% of the Pakistani strains belonged to 1 of the 10 main B2 subgroups (P = 0.001). Among the Swedish strains, the most common B2 subgroups were IX/STc95 (19%), II/STc73 (17%), VI/STc12 (13%), and III/STc127 (11%), with each subgroup carrying distinctive sets of ExPEC virulence markers. EPEC lineages with few ExPEC features constituted 47% of the Pakistani B2 strains but only 7% of the Swedish B2 strains (P = 0.0001). The subgroup distribution within phylogenetic group B2 strains colonizing the gut differed between Swedish and Pakistani infants. B2 subgroups with uropathogenic characteristics dominated the gut microbiota of Swedish infants, while EPEC lineage 1 strains frequently colonized the intestines of Pakistani infants. Moreover, within the B2 subgroups, ExPEC virulence genes were more prevalent in Swedish strains than in Pakistani strains. Thus, ExPEC traits exemplify the intestinal B2 strains from Western populations.IMPORTANCE The intestinal microbiota is an important reservoir for bacteria that cause extraintestinal infections. Escherichia coli is found ubiquitously in the gut microbiota, and it also causes urinary tract infections, infantile septicemia, and meningitis. Urinary tract infections are usually caused by E. coli strains that originate in the intestinal microbiota. E. coli also causes gastrointestinal infections and is a major cause of diarrhea in infants worldwide. The abilities of certain E. coli strains to cause infections are attributed to their virulence factors, i.e., bacterial components that contribute to the development of different diseases. Our study shows that different subtypes of potentially pathogenic E. coli strains dominate in the gut microbiota of infants in different geographical areas and expands our knowledge of the interplay between bacterial commensalism and pathogenicity.
Project description:Entomophthoromycota is one of six major phylogenetic lineages among the former phylum Zygomycota. These early terrestrial fungi share evolutionarily ancestral characters such as coenocytic mycelium and gametangiogamy as a sexual process resulting in zygospore formation. Previous molecular studies have shown the monophyly of Entomophthoromycota, thus justifying raising the taxonomic status of these fungi to a phylum. Multi-gene phylogenies have identified five major lineages of Entomophthoromycota. In this review we provide a detailed discussion about the biology and taxonomy of these lineages: I) Basidiobolus (Basidiobolomycetes: Basidiobolaceae; primarily saprobic); II) Conidiobolus (Entomophthoromycetes, Ancylistaceae; several clades of saprobes and invertebrate pathogens), as well as three rapidly evolving entomopathogenic lineages in the family Entomophthoraceae centering around; III) Batkoa; IV) Entomophthora and allied genera; and V) the subfamily Erynioideae which includes Zoophthora and allied genera. Molecular phylogenic analysis has recently determined the relationships of several taxa that were previously unresolved based on morphology alone: Eryniopsis, Macrobiotophthora, Massospora, Strongwellsea and two as yet undescribed genera of Basidiobolaceae.
Project description:Isolates of the Mycobacterium tuberculosis Beijing lineage are associated with high rates of transmission, hypervirulence and drug resistance. The Beijing lineage has been shown to dominate the tuberculosis (TB) epidemic in East Asia; however, the diversity and frequency of M. tuberculosis genotypes from Myanmar are unknown. We present the first comprehensive study describing the M. tuberculosis isolates circulating in Yangon, Myanmar. Thus, 310 isolates from pulmonary TB patients from Yangon, Myanmar, were genotyped by spoligotyping and IS6110-based restriction fragment length polymorphism analysis (IS6110 RFLP). The most frequent lineages observed were the East African-Indian (EAI; 48.4%; n = 150) and Beijing (31.9%; n = 99) lineages. Isolates belonging to the most frequent shared types (STs), ST1 (n = 98; Beijing), ST292 (n = 28; EAI), and ST89 (n = 11; EAI), had >or=75% similarity in their IS6110 patterns. Five of 11 Beijing isolates comprising five clusters with identical IS6110 RFLP patterns could be discriminated by mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) analysis. Of the 150 EAI isolates, 40 isolates (26.7%) had only one IS6110 copy, and 17 of these isolates could be discriminated by MIRU-VNTR analysis. The findings from this study suggest that although there is a predominance of the ancient EAI lineage in Yangon, the TB epidemic in Yangon is driven by clonal expansion of the ST1 genotype. The Beijing lineage isolates (21.4%) were more likely (P = 0.009) than EAI lineage isolates to be multidrug resistant (MDR) (1.3%; odds ratio, 3.2, adjusted for the patients' history of exposure to anti-TB drugs), suggesting that the spread of MDR Beijing isolates is a major problem in Yangon.
Project description:BackgroundWomen harboring BRCA1/2 germline mutations have high lifetime risk of developing breast/ovarian cancer. The recommendation to pursue BRCA1/2 testing is based on patient's family history of breast/ovarian cancer, age of disease-onset and/or pathologic parameters of breast tumors. Here, we investigated if diagnosis of triple-negative breast cancer (TNBC) independently increases risk of carrying a BRCA1/2 mutation in Pakistan.MethodsFive hundred and twenty-three breast cancer patients including 237 diagnosed ≤ 30 years of age and 286 with a family history of breast/ovarian cancer were screened for BRCA1/2 small-range mutations and large genomic rearrangements. Immunohistochemical analyses were performed at one center. Univariate and multiple logistic regression models were used to investigate possible differences in prevalence of BRCA1/2 mutations according to patient and tumor characteristics.ResultsThirty-seven percent of patients presented with TNBC. The prevalence of BRCA1 mutations was higher in patients with TNBC than non-TNBC (37 % vs. 10 %, P < 0.0001). 1 % of TNBC patients were observed to have BRCA2 mutations. Subgroup analyses revealed a larger proportion of BRCA1 mutations in TNBC than non-TNBC among patients 1) diagnosed at early-age with no family history of breast/ovarian cancer (14 % vs. 5 %, P = 0.03), 2) diagnosed at early-age irrespective of family history (28 % vs. 11 %, P = 0.0003), 3) had a family history of breast cancer (49 % vs. 12 %, P < 0.0001), and 4) those with family history of breast and ovarian cancer (81 % vs. 28 %, P = 0.0005). TNBC patients harboring BRCA1 mutations were diagnosed at a later age than non-carriers (median age at diagnosis: 30 years (range 22-53) vs. 28 years (range 18-67), P = 0.002). The association between TNBC status and presence of BRCA1 mutations was independent of the simultaneous consideration of family phenotype, tumor histology and grade in a multiple logistic regression model (Ratio of the probability of carrying BRCA1/2 mutations for TNBC vs. non-TNBC 4.23; 95 % CI 2.50-7.14; P < 0.0001).ConclusionGenetic BRCA1 testing should be considered for Pakistani women diagnosed with TNBC.
Project description:The Capnodiales incorporates plant and human pathogens, endophytes, saprobes and epiphytes, with a wide range of nutritional modes. Several species are lichenised, or occur as parasites on fungi, or animals. The aim of the present study was to use DNA sequence data of the nuclear ribosomal small and large subunit RNA genes to test the monophyly of the Capnodiales, and resolve families within the order. We designed primers to allow the amplification and sequencing of almost the complete nuclear ribosomal small and large subunit RNA genes. Other than the Capnodiaceae (sooty moulds), and the Davidiellaceae, which contains saprobes and plant pathogens, the order presently incorporates families of major plant pathological importance such as the Mycosphaerellaceae, Teratosphaeriaceae and Schizothyriaceae. The Piedraiaceae was not supported, but resolves in the Teratosphaeriaceae. The Dissoconiaceae is introduced as a new family to accommodate Dissoconium and Ramichloridium. Lichenisation, as well as the ability to be saprobic or plant pathogenic evolved more than once in several families, though the taxa in the upper clades of the tree lead us to conclude that the strictly plant pathogenic, nectrotrophic families evolved from saprobic ancestors (Capnodiaceae), which is the more primitive state.
Project description:Optical maps were generated for 33 uropathogenic Escherichia coli (UPEC) isolates. For individual genomes, the NcoI restriction fragments aligned into a unique chromosome map for each individual isolate, which was then compared with the in silico restriction maps of all of the sequenced E. coli and Shigella strains. All of the UPEC isolates clustered separately from the Shigella strains as well as the laboratory and enterohaemorrhagic E. coli strains. Moreover, the individual strains appeared to cluster into distinct subgroups based on the dendrogram analyses. Phylogenetic grouping of these 33 strains showed that 32/33 were the B2 subgroup and 1/33 was subgroup A. To further characterize the similarities and differences among the 33 isolates, pathogenicity island (PAI), haemolysin and virulence gene comparisons were performed. A strong correlation was observed between individual subgroups and virulence factor genes as well as haemolysis activity. Furthermore, there was considerable conservation of sequenced-strain PAIs in the specific subgroups. Strains with different antibiotic-resistance patterns also appeared to sort into separate subgroups. Thus, the optical maps distinguished the UPEC strains from other E. coli strains and further subdivided the strains into distinct subgroups. This optical mapping procedure holds promise as an alternative way to subgroup all E. coli strains, including those involved in infections outside of the intestinal tract and epidemic strains with distinct patterns of antibiotic resistance.
Project description:ObjectiveEarly detection of specific signs and symptoms to predict severe illness is essential to prevent infant mortality. As a continuation of the results from the multicenter Young Infants Clinical Signs and Symptoms (YICSS) study, we present here the performance of the seven-sign algorithm in 3 age categories (0-6 days, 7-27 days and 28-59 days) in Pakistani infants aged 0-59 days.ResultsFrom September 2003 to November 2004, 2950 infants were enrolled (age group 0-6 days = 1633, 7-27 days = 817, 28-59 days = 500). The common reason for seeking care was umbilical redness or discharge (29.2%) in the 0-6 days group. Older age groups presented with cough (16.9%) in the 7-27 age group and (26.9%) infants in the 28-59 days group. Severe infection/sepsis was the most common primary diagnoses in infants requiring hospitalization across all age groups. The algorithm performed well in every age group, with a sensitivity of 85.9% and specificity of 71.6% in the 0-6 days age group and a sensitivity of 80.5% and specificity of 80.2% in the 28-59 days group; the sensitivity was slightly lower in the 7-27 age group (72.4%) but the specificity remained high (83.1%).
Project description:Hybrid strains of Escherichia coli combine virulence traits of diarrheagenic (DEC) and extraintestinal pathogenic E. coli (ExPEC), but it is poorly understood whether these combined features improve the virulence potential of such strains. We have previously identified a uropathogenic E. coli (UPEC) strain (UPEC 252) harboring the eae gene that encodes the adhesin intimin and is located in the locus of enterocyte effacement (LEE) pathogenicity island. The LEE-encoded proteins allow enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) to form attaching and effacing (A/E) lesions in enterocytes. We sought to characterize UPEC 252 through whole-genome sequencing and phenotypic virulence assays. Genome analysis unveiled that this strain harbors a complete LEE region, with more than 97% of identity comparing to E2348/69 (EPEC) and O157:H7 Sakai (EHEC) prototype strains, which was functional, since UPEC 252 expressed the LEE-encoded proteins EspB and intimin and induced actin accumulation foci in HeLa cells. Phylogenetic analysis performed comparing 1,000 single-copy shared genes clustered UPEC 252 with atypical EPEC strains that belong to the sequence type 10, phylogroup A. Additionally, UPEC 252 was resistant to the bactericidal power of human serum and colonized cells of the urinary (T24 and HEK293-T) and intestinal (Caco-2 and LS174T) tracts. Our findings suggest that UPEC 252 is an atypical EPEC strain that emerges as a hybrid strain (aEPEC/UPEC), which could colonize new niches and potentially cause intestinal and extraintestinal infections.