Maria Magana

Terms of endearment: Bacteria meet graphene nanosurfaces

Microbial multidrug resistance poses serious risks in returning the human species into the pre-antibiotic era if it remains unsolved. While conventional research approaches to combat infectious diseases have been inadequate, nanomaterials are a promising alternative for the development of sound antimicrobial countermeasures. Graphene, a two-dimensional ultra-thin nanomaterial, possesses excellent electronic and biocompatibility properties, which position it in the biotechnology forefront for diverse applications in biosensing, therapeutics, diagnostics, drug delivery and device development. Yet, several questions remain unanswered. For instance, the way these nanosurfaces interact with the microbial entities is poorly understood. The mechanistic elucidation of this interface seems critical to determine the feasibility of applications under development. Are graphene derivatives appropriate materials to design potent antimicrobial agents, vehicles or effective diagnostic microsensors? Has the partition of major microbial resistance phenotypic determinants been sufficiently investigated? Can toxicity become a limiting factor? Are we getting closer to clinical implementation? To facilitate research conducive to answer such questions, this review describes the features of the graphene-bacterial interaction. An overview on paradigms of graphene-microbial interactions is expected to shed light on the range of materials available, and identify possible applications, serving the ultimate goal to develop deeper understanding and collective conscience for the true capabilities of this nanomaterial platform.

Detecting the Diversity of Mycoplasma and Ureaplasma Endosymbionts Hosted by Trichomonas vaginalis Isolates

Objectives: The symbiosis of Trichomonas vaginalis and Mycoplasma hominis is the first described association between two obligate human parasites. Trichomonas is the niche and the vector for the transmission of M. hominis infection. This clinically significant symbiosis may affect T. vaginalis virulence and susceptibility to treatment. The aims of this study were to investigate the intracellularly present Mycoplasma and Ureaplasma species in T. vaginalis strains isolated from the vaginal discharge of infected women as well as to trace the diversity pattern among the species detected in the isolated strains. Methods: Hundred pure T. vaginalis cultures were isolated from ~7,500 patient specimens presented with clinical purulent vaginitis. PCR and sequencing for Mycoplasma/Ureaplasma spp. were performed in DNA extracted from the pure cultures. In addition, vaginal discharge samples were cultured for the presence of M. hominis and U. urealyticum. Phylogenetic analysis assisted the identification of interspecies relationships between the Mycoplasma and Ureaplasma isolates. Results: Fifty four percentage of T. vaginalis isolates were harboring Mycoplasma spp. Phylogenetic analysis revealed three distinct clusters, two with already characterized M. hominis and Ureaplasma spp. (37% of total Mycoplasma spp.), whereas one group formed a distinct cluster matched with the newly identified species Candidatus Mycoplasma girerdii (59.3%) and one or more unknown Mycoplasma spp. (3.7%). Conclusions: T. vaginalis strains associated with vaginal infection might host intracellular mycoplasmas or ureaplasmas. Intracellular Mollicutes that remain undetected in the extracellular environment when conventional diagnostic methods are implemented may comprise either novel species, such as Candidatus M. giredii, or unknown species with yet unexplored clinical significance.

Effects of Yeast and Bacterial Commensals and Pathogens of the Female Genital Tract on the Transepithelial Electrical Resistance of HeLa Cells

Commensals of the human body can shift to a pathogenic phase when the host immune system is impaired. This study aims to investigate the effect of seven yeast and two bacterial commensals and opportunistic pathogens isolated from blood and the female genital tract on the transepithelial electrical resistance (TER) of human cervical epithelial cell cultures (HeLa). The pathogens Candida tropicalis, C. parapsilosis, C. glabrata, C. krusei, C. albicans and Saccharomyces cerevisiae, caused a significant decrease in TER as compared to the controls; Lactobacillus spp caused a significant increase in TER versus the controls and Escherichia coli had no effect on the TER of the cell monolayers. The above data show that Candida spp., S. cerevisiae and Lactobacillus spp. have a non-selective effect on the TER of HeLa cell monolayers. These results are consistent with the in vivo non-selective action of these microorganisms on the various human mucosal epithelia.

Options and Limitations in Clinical Investigation of Bacterial Biofilms

SUMMARY Bacteria can form single- and multispecies biofilms exhibiting diverse features based upon the microbial composition of their community and microenvironment. The study of bacterial biofilm development has received great interest in the past 20 years and is motivated by the elegant complexity characteristic of these multicellular communities and their role in infectious diseases. Biofilms can thrive on virtually any surface and can be beneficial or detrimental based upon the communitys interplay and the surface. Advances in the understanding of structural and functional variations and the roles that biofilms play in disease and host-pathogen interactions have been addressed through comprehensive literature searches. In this review article, a synopsis of the methodological landscape of biofilm analysis is provided, including an evaluation of the current trends in methodological research. We deem this worthwhile because a keyword-oriented bibliographical search reveals that less than 5% of the biofilm literature is devoted to methodology. In this report, we (i) summarize current methodologies for biofilm characterization, monitoring, and quantification; (ii) discuss advances in the discovery of effective imaging and sensing tools and modalities; (iii) provide an overview of tailored animal models that assess features of biofilm infections; and (iv) make recommendations defining the most appropriate methodological tools for clinical settings.

Inquiring into the Gaps of Campylobacter Surveillance Methods

Campylobacter is one of the most common pathogen-related causes of diarrheal illnesses globally and has been recognized as a significant factor of human disease for more than three decades. Molecular typing techniques and their combinations have allowed for species identification among members of the Campylobacter genus with good resolution, but the same tools usually fail to proceed to subtyping of closely related species due to high sequence similarity. This problem is exacerbated by the demanding conditions for isolation and detection from the human, animal or water samples as well as due to the difficulties during laboratory maintenance and long-term storage of the isolates. In an effort to define the ideal typing tool, we underline the strengths and limitations of the typing methodologies currently used to map the broad epidemiologic profile of campylobacteriosis in public health and outbreak investigations. The application of both the old and the new molecular typing tools is discussed and an indirect comparison is presented among the preferred techniques used in current research methodology.

Defining the microbial effluxome in the content of the host-microbiome interaction

Anastasios Ioannidis, Maria Magana, Cristian G. Bologa, Tudor I. Oprea, Ian T. Paulsen and George P. Tegos* 1 Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, Greece 2 Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece 3 Translational Informatics Division, Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM, USA 4 Department of Systems Biology, Center for Biological Sequence Analysis, Technical University of Denmark, Lyngby, Denmark 5 Department of Chemistry and Biomolecular Sciences, Macquarie University, NSW, Australia 6 Torrey Pines Institute for Molecular Studies, Port St. Lucie, FL, USA 7 Department of Dermatology, Harvard Medical School, Boston, MA, USA 8 Wellman Center for Photomedicine, Massachusetts General Hospital, Boston MA, USA *Correspondence: gtegos@tpims.org