Day 3 :
Keynote Forum
George L. Mendz
The University of Notre Dame, Australia
Keynote: The Vaginal Microbiome of Gravidae in Health and Disease
Time : 10.00AM
Biography:
Professor George L. Mendz has an MSc from the University of Barcelona (Spain), and a PhD from the University of NSW. He has been Lecturer at the College of Natural Sciences, the University of Puerto Rico (San Juan); Research Associate at the School of Chemistry and the Department of Biochemistry, the University of Sydney; ARC Senior Research Fellow and Associate Professor at the School of Biochemistry and Molecular Genetics, the University of NSW; Associate Professor at the Department of Bacteriology, the University of Bordeaux II; and Associate Professor at the School of Medical Sciences, the University of NSW.
Abstract:
Background: There is limited knowledge of the community structure of the vaginal microbiome of pregnant women. This work aimed to provide a more complete description the vaginal microbiome of pregnant women in late pregnancy, and to investigate differences between the microbiota of healthy gravidae women and those who experienced complications during pregnancy, in particular women giving birth at term or preterm. rnMethods: Upper vagina swabs were obtained from 225 women of Caucasian, Asian, Indian, Middle East, and Pacific Island racial backgrounds during the third trimester of pregnancy. Participating women were administered a questionnaire including demographic data and summarising the history of the pregnancy; 132 women of five ethnic backgrounds had no complications during the pregnancy. The identity of the taxa present was determined by ultrafast sequencing of the V1V3 regions of the 16S rDNA gene of DNA extracted from the swabs. The sequence data were analysed with MOTHUR and statistical analyses were performed employing various bioinformatics tools.rnResults and Discussion: The relative abundance of some phyla was different in pregnant and non-pregnant (from other studies) women. Multidimensional scaling analyses showed the bacterial populations of women without complications to cluster in four vaginotypes driven by four Lactobacillus species. This organisation was partially dependent on the racial background of the woman and was altered by complications during pregnancy. A CLUSTER analysis showed a fine structure in these vaginotypes created by taxa belonging to the genera Escherichia, Atopobium and Prevotella. The participants were stratified into two groups: with or without complications during pregnancy. Using univariate analysis, 9 genera were found significantly correlated with genital infections. PERMANOVA analyses yielded significant differences between the microbiomes of both groups
Keynote Forum
Mohamed Fakhr
University of Tulsa, USA
Keynote: Molecular Characterization of Staphylococci Isolated From Retail Mushrooms
Time : 10.30AM
Biography:
Mohamed K. Fakhr, is currently working as an Associate Professor of Molecular Microbiology in the Department of Biological Science at the University of Tulsa, USA. After obtaining his Ph.D. from Oklahoma State University in 2002, Dr. Fakhr, moved to North Dakota State University where he worked as a Postdoctoral Research Associate then a Research Assistant Professor at the Department of Veterinary and Microbiological Sciences. In 2008, Dr. Fakhr moved to Tulsa, where he currently runs an active research program in the area of Molecular Typing and Detection of Foodborne Bacterial Pathogens alongside exploring the mechanisms by which these foodborne pathogens develop resistance to antimicrobials
Abstract:
Staphylococcus spp. is a known cause of food poisoning in humans. The prevalence and virulence of staphylococci in retail mushrooms is understudied despite their proposed role as a mecA gene reservoir. One of the objectives of this study was to determine the prevalence of staphylococci in both conventional and organic retail mushrooms sold in the Tulsa, Oklahoma area. Characterizing the isolated strains for their possession of toxin and mecA genes was also aimed at. Molecular typing of the isolated strains to determine their origin and genetic diversity was also performed. A total of 420 samples of retail mushrooms were purchased from retail stores including Asian markets across the Tulsa area. Staphylococcus spp. was isolated from 14 different domestic and imported brands of fresh mushrooms. Prospective colonies of Staphylococcus aureus were identified by PCR and the presence of 18 toxin genes and the mecA gene were screened for by PCR. A total of 297/420 mushroom samples (70.71%) was positive for the presence of Staphylococcus spp. The prevalence of S. aureus in the tested mushroom samples was only 1.6%. The mecA gene was detected in 64/297 (21.55%) of the positive samples. A total of 552 isolated staphylococcal strains were also tested for the presence of 18 toxin genes. The prevalence of enterotoxins ranged from 0.1% to 2.1%. The see, sej and sei genes were the most detected enterotoxins among all isolates and the exfoliative toxin (eta) gene was detected in only one isolate. The genes of toxic shock syndrome toxin 1, leucocidins (lukE/lukD and lukM), and Panton-Valentine leucocidin (PVL) were not detected in any of the staphylococcal isolates screened. A subset of 120 staphylococcal isolates was subjected to 16S rDNA gene sequencing and was molecularly identified. A total of 10 different Staphylococcus species was detected including S. aureus, S. fleurettii, S. saprophyticus, S. vitulinus, S. sciuri, S. xylosus, S. succinus, S. pasteuri, S. warneri, and S. haemolyticus. More than half of the screened S. fleurettii strains carried the mecA gene. Genetic diversity among the identified staphylococci strains showed higher diversity reflecting the mushroom compost environment. Genetic diversity in the mecA gene among a selected number of isolated staphylococci in this study showed a higher degree of DNA homology among the isolates, indicating that these isolates can serve as a reservoir of this important gene in the environment. Molecular typing using PFGE for the identified staphylococci showed a high degree of diversity that varied according to the mushroom brand. PFGE, MLST and spa typing of the isolated S. aureus strains showed two distinct strains of a human origin, supporting that contamination with S. aureus was as a result of human handling of the mushrooms during packaging. In conclusion, the prevalence of Staphylococcus spp. in fresh mushrooms is high and a subset of the strains was shown to harbor enterotoxin genes, which might lead to foodborne poisoning. The mecA screening and genetic diversity results support the hypothesis that those staphylococci other than S. aureus can serve as reservoirs for this methicillin resistance gene.