Bacteriology Commons^™

Identification Of Novel Small Rnas And Characterization Of The 6s Rna Of Coxiella Burnetii, Indu Warrier, Linda D. Hicks, James M. Battisti, Rahul Raghavan, Michael F. Minnick

Biological Sciences Faculty Publications

Coxiella burnetii, an obligate intracellular bacterial pathogen that causes Q fever, undergoes a biphasic developmental cycle that alternates between a metabolically-active large cell variant (LCV) and a dormant small cell variant (SCV). As such, the bacterium undoubtedly employs complex modes of regulating its lifecycle, metabolism and pathogenesis. Small RNAs (sRNAs) have been shown to play important regulatory roles in controlling metabolism and virulence in several pathogenic bacteria. We hypothesize that sRNAs are involved in regulating growth and development of C. burnetii and its infection of host cells. To address the hypothesis and identify potential sRNAs, we subjected total RNA …

Investigating The Viability Of Two Stenotrophomonas Maltophilia Isolates After Air-Drying, Samantha Lane, Joanna Brooke

DePaul Discoveries

Abstract

Stenotrophomonas maltophilia is a water-borne infectious bacterium that is found in both clinical (hospitals) and non-clinical environments. This human pathogen is commonly recovered from respiratory tract infections. A recent study at a hospital in Taiwan suggested that dry patient charts can serve as a vehicle of transmission of this bacterium⁷. As S. maltophilia is not commonly isolated from dry surfaces, this current study tested the hypothesis that this pathogen can remain viable for some time on a dry surface. This study was designed to determine how long S. maltophilia could remain viable after air-drying by observing …

Large Scale Screening Of Digeneans For Neorickettsia Endosymbionts Using Real-Time Pcr Reveals New Neorickettsia Genotypes, Host Associations And Geographic Records, Stephen Greiman, Vasyl V. Tkach, Eric Pulis, Thomas J. Fayton, Stephen S. Curran

Faculty Publications

Digeneans are endoparasitic flatworms with complex life cycles including one or two intermediate hosts (first of which is always a mollusk) and a vertebrate definitive host. Digeneans may harbor intracellular endosymbiotic bacteria belonging to the genus Neorickettsia (order Rickettsiales, family Anaplasmataceae). Some Neorickettsia are able to invade cells of the digenean's vertebrate host and are known to cause diseases of wildlife and humans. In this study we report the results of screening 771 digenean samples for Neorickettsia collected from various vertebrates in terrestrial, freshwater, brackish, and marine habitats in the United States, China and Australia. Neorickettsia were detected using a …

Characterizing The Response Of Multidrug-Resistant Klebsiella Pneumoniae Species To The Application Of A Phage Cocktail, Steven Liu

Symposium

Project Summary: The application of bacteriophages to treat bacterial infections is known as phage therapy, which takes advantage of bacteriophage’s natural ability to infect and lyse bacterial hosts. Phages have been shaped by billions of years of evolution to be highly specialized deliverers of bactericidal agents to the cytoplasm of their target bacteria. Ever since discovery of bacteriophages in 1915, phage therapy was recognized as a potentially powerful tool for eliminating bacterial infections. The effectiveness of phage therapy can be increased by creating a mixture of multiple phages to target a wider variety of bacterial strains. Furthermore, phage therapy has …

Temporal Variations In The Abundance And Composition Of Biofilm Communities Colonizing Drinking Water Distribution Pipes, John J. Kelly, Nicole Minalt, Alessandro Culotti, Marsha Pryor, Aaron Packman

Biology: Faculty Publications and Other Works

Pipes that transport drinking water through municipal drinking water distribution systems (DWDS) are challenging habitats for microorganisms. Distribution networks are dark, oligotrophic and contain disinfectants; yet microbes frequently form biofilms attached to interior surfaces of DWDS pipes. Relatively little is known about the species composition and ecology of these biofilms due to challenges associated with sample acquisition from actual DWDS. We report the analysis of biofilms from five pipe samples collected from the same region of a DWDS in Florida, USA, over an 18 month period between February 2011 and August 2012. The bacterial abundance and composition of biofilm communities …

Structural Features Of The Pseudomonas Fluorescens Biofilm Adhesin Lapa Required For Lapg-Dependent Cleavage, Biofilm Formation, And Cell Surface Localization, Chelsea D. Boyd, T. Jarrod Smith, Sofiane El-Kirat-Chatel, Peter D. Newell, Yves F. Dufrêne, George A. O'Toole

Dartmouth Scholarship

The localization of the LapA protein to the cell surface is a key step required by Pseudomonas fluorescens Pf0-1 to irreversibly attach to a surface and form a biofilm. LapA is a member of a diverse family of predicted bacterial adhesins, and although lacking a high degree of sequence similarity, family members do share common predicted domains. Here, using mutational analysis, we determine the significance of each domain feature of LapA in relation to its export and localization to the cell surface and function in biofilm formation. Our previous work showed that the N terminus of LapA is required for …

Characterization Of Ftsa-Ftsn Interaction During Escherichia Coli Cell Division, [email protected] K. Busiek

Dissertations and Theses (Open Access)

Division of a bacterial cell into two equal daughter cells requires precise assembly and constriction of the division machinery, or divisome. The Escherichia coli divisome includes nearly a dozen essential cell division proteins that assemble at midcell between segregating sister chromosomes. FtsZ, a homolog of eukaryotic tubulin, is the first essential cell division protein to localize at midcell where it polymerizes into a ring-shaped scaffold (Z ring). Establishment of the Z ring is required for recruitment of downstream cell division proteins including FtsA, a cytoplasmic protein that tethers the Z ring to the inner membrane. Following localization of FtsA and …

The Adherence Of Escherichia Coli 0157:H7 On Lettuce Leaves Over Time And Removal Technique Using Chlorinated Water, Karenzha Huwae

Undergraduate Research Symposium

EHEC 0157:H7 causes hemorrhagic colitis (HUS) characterized by renal injury that leads to permanent kidney failure, impairment of the central nervous system, and ultimately death. Fresh leafy produce has carried the 10 organisms needed for illness. Thus understanding the behavior of EHEC on produce is essential. Previous research conducted in Spring 2013 showed that EHEC did not grow as well as E. coli lab strain on lettuce leaves. Both strains grew better at room temperature rather than at 4C temperature. This project examines the adherence of EHEC on the lettuce surface as a factor of time and the effectiveness of …

Role Of The Apee Esterase In The Growth Of Salmonella On Phospholipids As Phosphate Sources, Stella Menuba

Undergraduate Research Symposium

Salmonella enterica serovar Typhimurium, a bacterium frequently implicated in outbreaks of food poisoning, is able to survive in limiting phosphate environments by inducing a number of proteins that allow it to use a variety of compounds as phosphate sources. The gene apeE is induced when the cells are starved for phosphate. This gene encodes an outer membrane esterase that is not found in E. coli, and has been shown to be necessary for the growth of Salmonella Typhimurium in phosphate-limiting environments, such as those that may be encountered in an egg. To demonstrate the role of apeE in these environments, …

Carriage Of Methicillin Resistance In Coagulase-Negative Staphylococci, Christa Moller

Undergraduate Research Symposium

Methicillin-resistant Staphylococcus aureus (MRSA) is becoming more commonly encountered in clinical settings. The prevalence of methicillin resistance in Staphylococcus species other than Staphylococcus aureus, and therefore the potential for the former to serve as a reservoir for methicillin resistance has not been studied in great detail. Staphylococcus species isolated from students as part of a class exercise in Medical Microbiology in 2012 were screened for resistance to oxacillin, which is similar to methicillin and is prescribed much more frequently. The identification of isolates was verified, and isolates were screened on oxacillin screening agar plates. Isolates that screened positive for oxacillin …

Colonization Of Intestinal Pathogen Changes The Gut Microbiota, Kaitlyn Shondelmyer

Senior Honors Theses

Enterohemorrhagic Escherechia coli is a serious human pathogen causing bloody diarrhea and hemolytic uremic syndrome. It is difficult to study in animal models, but pathogenesis may be modeled in mice with the similar murine pathogen, Citrobacter rodentium. C. rodentium does not cause disease in streptomycin-treated mice, suggesting that it is competition with other facultative anaerobes that triggers pathogenesis. Streptomycin-treated mice were co-colonized with C. rodentium and a commensal E. coli strain. The intestinal microbiota of each group was observed over a 15-day period using quantitative PCR. Colon weights were also measured over the same period. Results indicate that the …

The Toxavapa Toxin-Antitoxin Locus Contributes To The Survival Of Nontypeable Haemophilus Influenzae During Infection, Dabin Ren, Alexis A. Kordis, Daniel E. Sonenshine, Dayle A. Daines

Biological Sciences Faculty Publications

Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that is a common cause of acute and recurrent mucosal infections. One uncharacterized NTHi toxin-antitoxin (TA) module, NTHI1912-1913, is a host inhibition of growth (higBA) homologue. We hypothesized that this locus, which we designated toxAvapA, contributed to NTHi survival during infection. We deleted toxAvapA and determined that growth of the mutant in defined media was not different from the parent strain. We tested the mutant for persistence during long-term in vitro co-culture with primary human respiratory tissues, which revealed that the DeltatoxAvapA mutant was attenuated for survival. We then …

Transcriptome Analysis Of Listeria Monocytogenes Exposed To Biocide Stress Reveals A Multi-System Response Involving Cell Wall Synthesis, Sugar Uptake, And Motility, Aidan Casey, Edward M. Fox, Stephan Schmitz-Esser, Aidan Coffey, Olivia Mcauliffe, Kieran Jordan

Department of Biological Sciences Publications

Listeria monocytogenes is a virulent food-borne pathogen most often associated with the consumption of “ready-to-eat” foods. The organism is a common contaminant of food processing plants where it may persist for extended periods of time. A commonly used approach for the control of Listeria monocytogenes in the processing environment is the application of biocides such as quaternary ammonium compounds. In this study, the transcriptomic response of a persistent strain of L. monocytogenes (strain 6179) on exposure to a sub-lethal concentration of the quaternary ammonium compound benzethonium chloride (BZT) was assessed. Using RNA-Seq, gene expression levels were quantified by sequencing …

Acanthamoeba And Bacteria Produce Antimicrobials To Target Their Counterpart, Junaid Iqbal, Ruqaiyyah Siddiqui, Naveed Ahmed Khan

Department of Biological & Biomedical Sciences

Background

In the microbial ecosystem, microbes compete for space and nutrients. Consequently, some have developed the ability to kill or inhibit the growth of other competing microbes by producing antimicrobial substances. As the ‘producer’ species are generally immune to these substances, their compounds act on the competing microbial species and give the producer more space and access to nutrients for growth. Many currently used antibiotics were developed by exploiting this potential of certain microbes.

Findings

Here, the free-living amoeba, Acanthamoeba castellanii, was investigated for its antibacterial activity against representative Gram positive and Gram negative bacteria, while bacterial isolates were …

Phages Of Non-Diary Lactococci: Isolation And Characterization Of Phi L47, A Phage Infecting The Grass Isolate Lactococcus Lactis Ssp Cremoris Dpc6860, Daniel Cavanagh, Caitríona M. Guinane, Horst Neve, Aidan Coffey, R. Paul Ross, Gerald F. Fitzgerald, Olivia Mcauliffe

Department of Biological Sciences Publications

Lactococci isolated from non-dairy sources have been found to possess enhanced metabolic activity when compared to dairy strains. These capabilities may be harnessed through the use of these strains as starter or adjunct cultures to produce more diverse flavor profiles in cheese and other dairy products. To understand the interactions between these organisms and the phages that infect them, a number of phages were isolated against lactococcal strains of non-dairy origin. One such phage, ΦL47, was isolated from a sewage sample using the grass isolate L. lactis ssp. cremoris DPC6860 as a host. Visualization of phage virions by transmission electron …

Listeria Monocytogenes Can Utilize Both M Cell Transcytosis And Inla-Mediated Uptake To Cross The Epithelial Barrier Of The Intestine During An Oral Infection Model Of Listeriosis, Hilary Denney

Theses and Dissertations--Medical Sciences

The invasive pathways, InlA- and InB-mediated uptake and M cell transcytosis, that Listeria monocytogenes uses to invade the intestine have mainly been studied using infection models that do not truly replicate what occurs during a natural infection. Recently, our lab has developed an oral infection model that is more physiolocally relevant to what occurs during food borne listeriosis. We have sought to evaluate the relative roles of the previously defined invasive pathways, in our oral model of infection. We have done this by utilizing an InlAmCG Lm strain that is able to bind murine E-cadherin, knockout Lm strains, ΔinlA Lm …

Sporulation In Bacteria: Beyond The Standard Model, Elizabeth Hutchison

Biology

Endospore formation follows a complex, highly regulated developmental pathway that occurs in a broad range of Firmicutes. Although Bacillus subtilis has served as a powerful model system to study the morphological, biochemical, and genetic determinants of sporulation, fundamental aspects of the program remain mysterious for other genera. For example, it is entirely unknown how most lineages within the Firmicutes regulate entry into sporulation. Additionally, little is known about how the sporulation pathway has evolved novel spore forms and reproductive schemes. Here, we describe endospore and internal offspring development in diverse Firmicutes and outline progress in characterizing these programs. Moreover, …

Anaplasma Phagocytophilum Nutritional Virulence Mechanisms Target The Host Cell Secretory Pathway, Hilary Kay Truchan

Theses and Dissertations

Obligate intracellular pathogens must acquire host cell-derived nutrients to facilitate their survival. One such bacterial pathogen, Anaplasma phagocytophilum, replicates within neutrophils and non-phagocytic cells in a bacterial-modified, host cell-derived vacuole. The bacterium exploits host cell vesicular trafficking pathways to route nutrients to its vacuole and utilizes Rab GTPases, guanine nucleotide-dependent, vesicular trafficking regulators, to do so. We previously discovered that the A. phagocytophilum vacuolar membrane is decorated with a specific subset of Rab GTPases - Rab1, Rab4A, Rab10, Rab11, Rab14, Rab22A and Rab35. Rab1 is exclusively found on the endoplasmic reticulum (ER) and thus its localization suggests that the …

The Prevalence And Effect Of Wolbachia Infection On The Brown Widow Spider (Latrodectus Geometricus), Brittany Dane' Arrington

College of Graduate Studies: Theses & Dissertations

Wolbachia was recently identified in the Brown Widow Spider (Latrodectus geometricus). This symbiont has not previously been found in this genus, therefore the consequences on the host’s population dynamics are unknown. The frequency of endosymbiont infection can provide insight into the population dynamics of the host as this bacteria is known to alter host life history. In my 1^st chapter I determine the prevalence of Wolbachia pipentis infection in in the Brown Widow Spider (Latrodectus geometricus) from five locations in the Southeastern United States. Infection frequency differed significantly among sampling locations, ranging from 20% to …

A Prospective Study Of Periodontal Disease And Risk Of Gastric And Duodenal Ulcer In Male Health Professionals, Matthew R. Boylan, Hamed Khalili, Edward S. Huang, Dominique S. Michaud, Jacques Izard, Kaumudi J. Joshipura, Andrew T. Chan

Department of Food Science and Technology: Faculty Publications

Periodontal disease is characterized by microbial shifts within the oral cavity and chronic inflammation of the gingival tissue, and can lead to tooth loss. Several studies support an association between periodontal disease and risk of chronic systemic conditions, including vascular disease, chronic obstructive pulmonary disease, diabetes mellitus, and cancer, including gastric adenocarcinoma. These associations may be mediated by systemic inflammation, the immune response to periodontal infection, or direct invasion by pathogens. Previous studies of periodontal disease and risk of peptic ulcer have been limited by cross-sectional design, diagnoses that were not confirmed by medical record review, and a lack of …