Pathogenic Microbiology Commons^™

Antibiotic Efficacy And Interaction In Escherichia Coli During Varying Nutrient Conditions, Kristina K. Millar

Scripps Senior Theses

Due to the recent rise in antibiotic resistant pathogens, and the difficulties surrounding the quest for new antibiotics, many researchers have started revisiting antibiotic interactions in hopes of finding new treatment options. The primary outcome of this project was to examine the efficacy of concomitant antibiotic use under varying nutrient conditions, to identify variations in antibiotic interactions. Antibiotic interactions were studied, utilizing E. coli as a model bacterial system, grown in four different media types. E. coli cultures were treated with streptomycin, tobramycin, erythromycin, and amikacin individually and in a pairwise fashion at varying doses. We found that at least …

Design And Testing Of Novel Anthrax Vaccines Utilizing A Tobacco Mosaic Virus Expression System, Ryan C. Mccomb

KGI Theses and Dissertations

Anthrax is a potentially fatal disease caused by the bacteria Bacillus anthracis. Infection and disease occur after spores gain entry into the body, germinate into vegetative bacteria, and produce toxin. Bacillus anthracis spores have been engineered as bioweapons and have been used repeatedly in warfare and terrorism to inflict casualties in military and civilian populations. Currently, only one vaccine has been approved for prevention of anthrax in the United States. This vaccine is an undefined product that is difficult to produce, requires a long vaccination schedule, and is reactogenic. Efforts to make an improved anthrax vaccine are being pursued. …

A Tail Of Two Phages: Genomic And Functional Analysis Of Listeria Monocytogenes Phages Vb_Lmos_188 And Vb_Lmos_293 Reveal The Receptor-Binding Proteins Involved In Host Specificity, Aidan Casey, Kieran Jordan, Horst Neve, Aidan Coffey, Olivia Mcauliffe

Department of Biological Sciences Publications

The physical characteristics of bacteriophages establish them as viable candidates for downstream development of pathogen detection assays and biocontrol measures. To utilize phages for such purposes, a detailed knowledge of their host interaction mechanisms is a prerequisite. There is currently a wealth of knowledge available concerning Gram-negative phage-host interaction, but little by comparison for Gram-positive phages and Listeria phages in particular. In this research, the lytic spectrum of two recently isolated Listeria monocytogenes phages (vB_LmoS_188 and vB_LmoS_293) was determined, and the genomic basis for their observed serotype 4b/4e host-specificity was investigated using comparative genomics. The late tail genes of these …

Tonb Not Directly Related To Efflux Of Antibiotics In E. Coli, Amber Gombash

Honors Projects

Studies in Pseudomonas aeruginosa have suggested that the TonB energy transduction system directly contributes to efflux-mediated antibiotic resistance, ostensibly by energizing one or more efflux systems. We have found ∆tonB strains of Escherichia coli to similarly be more sensitive to certain antibiotics relative to wild-type strains. To test the hypothesis that this enhanced sensitivity involved the energization of efflux systems, sensitivity patterns for a variety of antibiotics were evaluated using a set of strains differentially lacking genes encoding the Acr efflux system, the universal outer membrane efflux portal TolC, and TonB. No correlation was evident between the resistance phenotypes of …

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 …

Microbiota, Oral Microbiome, And Pancreatic Cancer, Dominique S. Michaud, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Only 30% of patients diagnosed with pancreatic cancer survive one year post-diagnosis. Progress in understanding the causes of pancreatic cancer has been made, including solidifying the associations with obesity and diabetes, and a proportion of cases should be preventable through lifestyle modifications. Unfortunately, identifying reliable biomarkers of early pancreatic cancer has been extremely challenging, and no effective screening modality is currently available for this devastating form of cancer. Recent data suggest the microbiota may play a role in the disease process, but many questions remain. Future studies focusing on the human microbiome, both etiologically and as a marker of disease …

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 …

The Effects Of Lipoxin A4 (Lxa4) On Neutrophil Biology In Sepsis, Benedict Wu

Graduate School of Biomedical Sciences Theses and Dissertations

During sepsis, neutrophils are inappropriately activated and have prolonged lifespans, thus becoming dysfunctional. Excessive neutrophil activation can lead to tissue injury while neutrophil dysfunction can lead to decreased free radical production and reduced phagocytosis, preventing the host from clearing preexisting infections. Lipoxin A4 (LXA4) is a specialized pro-resolution mediator which reduces neutrophil migration and expression of proinflammatory mediators. Intact neutrophil functions are critical for the host to efficiently clear invading pathogens. The effects of LXA4 on neutrophil function in sepsis have not been established. Using the cecal ligation and puncture (CLP) model of sepsis, LXA4 administered 1 h after sepsis …

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 …

Mycological Study For A Management Plan Of A Neotropical Show Cave (Brazil), Erika Linzi Silva Taylor, Maria Aparecida De Resende Stoianoff, Rodrigo Lopes Ferreira

International Journal of Speleology

Caves are stable environments with characteristics favoring the development of microorganisms. The allocthonous input of organic matter and microbes into the warm Neotropical caves may favor the development of filamentous fungi, including pathogenic species. Histoplasma capsulatum is a pathogenic species commonly found in caves and associated with bat and bird guano. Many Brazilian caves have been historically visited due to scenic and religious tourism. The objective of this study was to perform a microbiology study for a management plan of a show cave in Brazil, focusing on the presence and distribution of pathogenic and opportunistic fungi in the cave. Statistics …

Proteomic Studies Of The Influenza Virus-Human Cell Interactions: The Responses Of Host Cell Protein Expression To Viral Infection And The Novel Host Proteins That Interact With Virus Protein Ns1, Yimeng Wang

Graduate Theses and Dissertations

Influenza A viruses (IAVs) continue to be a threat to human health. Despite extensive studies, the mechanisms underlying the IAVs-host interactions during IAV infection remain elusive. We employed quantitative proteomic methods to systematically explore the host cell protein expression responses to IAV infection and examine the function of a critical IAV protein called NS1 by identifying its host binding partners. Specifically, we used a 2-dimentional gel electrophoresis (2-DE) based proteomic method to screen host proteins whose expression was substantially altered by IAV. One critical protein named IκB kinase-gamma (IKKγ) was found to be significantly down-regulated during IAV infection. Functional studies …

Neisseria Oralis Sp. Nov., Isolated From Healthy Gingival Plaque And Clinical Samples, William J. Wolfgang, Teresa V. Passaretti, Reashma Jose, Jocelyn Cole, An Coorevits, Andrea N. Carpenter, Sherly Jose, Anita Van Landschoot, Jacques Izard, Donna J. Kohlerschmidt, Peter Vandamme, Floyd E. Dewhirst, Mark A. Fisher, Kimberlee A. Musser

Department of Food Science and Technology: Faculty Publications

A polyphasic analysis was undertaken of seven independent isolates of gram-negative cocci collected from pathological clinical samples from New York, Louisiana, Florida, and Illinois and healthy subgingival plaque from a patient in Virginia, USA. The 16S rRNA gene sequence similarity among these isolates was 99.7–100 %, and the closest species with a validly published name was Neisseria lactamica (96.9 % similarity to the type strain). DNA–DNA hybridization confirmed that these isolates are of the same species and are distinct from their nearest phylogenetic neighbor, N. lactamica. Phylogenetic analysis of 16S and 23S rRNA gene sequences indicated that the …

Composition Of The Adult Digestive Tract Bacterial Microbiome Based On Seven Mouth Surfaces, Tonsils, Throat And Stool Samples, Nicola Segata, Susan Kinder Haake, Peter Mannon, Katherine P. Lemon, Levi Waldron, Dirk Gevers, Curtis Huttenhower, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Background: To understand the relationship between our bacterial microbiome and health, it is essential to define the microbiome in the absence of disease. The digestive tract includes diverse habitats and hosts the human body’s greatest bacterial density. We describe the bacterial community composition of ten digestive tract sites from more than 200 normal adults enrolled in the Human Microbiome Project, and metagenomically determined metabolic potentials of four representative sites.

Results: The microbiota of these diverse habitats formed four groups based on similar community compositions: buccal mucosa, keratinized gingiva, hard palate; saliva, tongue, tonsils, throat; sub- and supra-gingival plaques; …

Emerging Dynamics Of Human Campylobacteriosis In Southern Ireland, Susan Bullman, Daniel Corcoran, James O'Leary, Derry O'Hare, Brigid Lucey, Roy D. Sleator

Department of Biological Sciences Publications

Infections with Campylobacter spp. pose a significant health burden worldwide. The significance of Campylobacter jejuni/Campylobacter coli infection is well appreciated but the contribution of non-C. jejuni/C. coli spp. to human gastroenteritis is largely unknown. In this study, we employed a two-tiered molecular study on 7194 patient faecal samples received by the Microbiology Department in Cork University Hospital during 2009. The first step, using EntericBio® (Serosep), a multiplex PCR system, detected Campylobacter to the genus level. The second step, utilizing Campylobacter species-specific PCR identified to the species level. A total of 340 samples were confirmed as Campylobacter genus positive, 329 of …

An Investigation Of The Subtype Diversity Of Clinical Isolates Of Irish Clostridium Difficile Ribotypes 027 And 078 By Repetitive-Extragenic Palindromic Pcr, Denise Drudy, K. Solomon, S. Murray, L. Scott, S. Mcdermott,, A. Martin, C. O’Donoghue, M. Skally, K. Burns, L. Fenelon, F. Fitzpatrick,, L. Kyne, S. Fanning

Articles

A repetitive-extragenic palindromic PCR (rep-PCR) subtyping method (DiversiLab) in conjunction with ribotyping, toxinotyping and antimicrobial-susceptibility testing was used to detect subtypes within Clostridium difficile ribotypes 027 and 078. Clinical isolates of ribotypes 027 (toxinotype III) (n530) and 078 (toxinotype V) (n523) were provided by health-care facilities across the Republic of Ireland over 2 months in 2006 and 1 month in 2009. Ribotype 027 isolates were significantly more related to each other (9 different subtype profiles) when compared to ribotype 078 isolates (14 different profiles) (P50.001; cut-off .90 % similarity). Almost half of ribotype 078 isolates (45.5 %) showed no relationship …

Campylobacter Ureolyticus: An Emerging Gastrointestinal Pathogen?, Susan Bullman, Daniel Corcoran, James O'Leary, Brigid Lucey, Deirdre Byrne, Roy D. Sleator

Department of Biological Sciences Publications

A total of 7194 faecal samples collected over a 1-year period from patients presenting with diarrhoea were screened for Campylobacter spp. using EntericBios, a multiplex-PCR system. Of 349 Campylobacter-positive samples, 23.8% were shown to be Campylobacter ureolyticus, using a combination of 16S rRNA gene analysis and highly specific primers targeting the HSP60 gene of this organism. This is, to the best of our knowledge, the first report of C. ureolyticus in the faeces of patients presenting with gastroenteritis and may suggest a role for this organism as an emerging enteric pathogen.

Killing Of Treponema Denticola By Mouse Peritoneal Macrophages, P. Gaibani, C. Vocale, S. Ambretti, F. Cavrini, Jacques Izard, L. Miragliotta, M. T. Pellegrino, V. Sambri

Department of Food Science and Technology: Faculty Publications

Treponema denticola has been identified as an important cause of periodontal disease and hypothesized to be involved in extra-oral infections. The objective of this study was to investigate the role of T. denticola cell length and motility during mouse peritoneal macrophages in vitro uptake. Macrophages, incubated under aerobic and anaerobic conditions, produced a similar amount of TNF-α when stimulated with Escherichia coli LPS. The uptake of FlgE- and CfpA-deficient mutants of T. denticola was significantly increased compared with the wild-type strain, due to cell size or lack of motility. Opsonization with specific antibodies considerably improved the treponemes’ uptake. …

Cloning And Expression Of A Putative Exported Protein Coding Gene Sas1089 From An Invasive Community Associated Staphylococcus Aureus Strain Mssa476, Nailah Alzaki

All-Inclusive List of Electronic Theses and Dissertations

Originally, methicillin resistant Staphylococcus aureus (MRSA) occurred primarily in the hospital setting and was designated hospital- associated MRSA (HA-MRSA). In recent years, isolates of Staphylococcus aureus from the community (CA-MRSA), found to be methicillin resistant, are not as resistant tooth~ antibiotics as HA-MRSA. However, community strains are noted for their invasiveness causing soft tissue infections with propensity for invasion to deeper sites.

Native Cellular Architecture Of Treponema Denticola Revealed By Cryo-Electron Tomography, Jacques Izard, Chyong-Ere Hsieh, Ronald J. Limberger, Carmen A. Mannella, Michael Marko

Department of Food Science and Technology: Faculty Publications

Using cryo-electron tomography, we are developing a refined description of native cellular structures in the pathogenic spirochete Treponema denticola. Tightly organized bundles of periplasmic flagella were readily observed in intact plunge-frozen cells. The periplasmic space was measured in both wild-type and aflagellate strains, and found to widen by less than the diameter of flagella when the latter are present. This suggests that a structural change occurs in the peptidoglycan layer to accommodate the presence of the flagella. In dividing cells, the flagellar filaments were found to bridge the cytoplasmic cylinder constriction site. Cytoplasmic filaments, adjacent to the inner membrane, …

An Evaluation Of Methicillin Resistant Staphylococcus Aureus Survival On Five Environmental Surfaces Under Two Different Humidities, With And Without The Addition Of Bovine Serum Albumin, Courtney Ann Coughenour

UNLV Theses, Dissertations, Professional Papers, and Capstones

The spread of antibiotic resistant bacteria is a major public health concern, as they result in greater healthcare costs and increased morbidity and mortality rates. Methicillin resistant Staphylococcus aureus (MRSA) is one organism of particular concern, with the number of infections increasing in epidemic proportion. Bacterial surface contamination with MRSA is significant, as it may serve as a reservoir for transmission and have negative health implications. The purpose of this study was to evaluate survival of MRSA on five environmental surface materials; glass, wood, vinyl, plastic, and cloth. The effect of relative humidity (RH) and bovine serum albumin (BSA) were …

Pyramidobacter Piscolens Gen. Nov., Sp. Nov., A Member Of The Phylum ‘Synergistetes’ Isolated From The Human Oral Cavity, Julia Downes, Sonia R. Vartoukian, Floyd E. Dewhirst, Jacques Izard, Tsute Chen, Wen-Han Yu, Iain C. Sutcliffe, William G. Wade

Department of Food Science and Technology: Faculty Publications

Four strains of anaerobic, gram-negative bacilli isolated from the human oral cavity were subjected to a comprehensive range of phenotypic and genotypic tests and were found to comprise a homogeneous group distinct from any species with validly published names. 16S rRNA and 23S rRNA gene sequence analyses and DNA–DNA reassociation data revealed that the strains constituted a novel group within the phylum ‘Synergistetes’ and were most closely related to Jonquetella anthropi. Two libraries of randomly cloned DNA were prepared from strain W5455T and were sequenced to provide a genome survey as a resource for metagenomic studies. A new genus …

Cryo-Electron Tomography Elucidates The Molecular Architecture Of Treponema Pallidum, The Syphilis Spirochete, Jacques Izard, Christian Renken, Chyong-Ere Hsieh, Daniel C. Desrosiers, Star Dunham-Ems, Carson La Vake, Linda L. Gebhardt, Ronald J. Limberger, David L. Cox, Michael Marko, Justin D. Radolf

Department of Food Science and Technology: Faculty Publications

Cryo-electron tomography (CET) was used to examine the native cellular organization of Treponema pallidum, the syphilis spirochete. T. pallidum cells appeared to form flat waves, did not contain an outer coat and, except for bulges over the basal bodies and widening in the vicinity of flagellar filaments, displayed a uniform periplasmic space. Although the outer membrane (OM) generally was smooth in contour, OM extrusions and blebs frequently were observed, highlighting the structure’s fluidity and lack of attachment to underlying periplasmic constituents. Cytoplasmic filaments converged from their attachment points opposite the basal bodies to form arrays that ran roughly …

Periplasm Organization In Treponema Denticola As Studied By Cryo-Electron Tomography, Jacques Izard, C.-E. Hsieh, C. A. Mannella, Ronald J. Limberger, M. Marko

Department of Food Science and Technology: Faculty Publications

As a spirochete, the genus Treponema is one of the few major bacterial groups whose natural phylogenic relationships are evident at the level of gross phenotypic characteristics such as their morphology. Treponema spp. are highly invasive due to their unique motility in dense media, and their ability to penetrate cell layers. This feature is associated with the helical cell body and the presence of flagellar filaments in the periplasm. Treponema denticola is an oral pathogen involved in endodontic infections and periodontal diseases. The presence and quantity of T. denticola in the subgingival biofilm is correlated with the severity of periodontal …

Tomographic Reconstruction Of Treponemal Cytoplasmic Filaments Reveals Novel Bridging And Anchoring Components, Jacques Izard, Bruce F. Mcewen, Rita M. Barnard, Thomas Portuese, William A. Samsonoff, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

An understanding of the involvement of bacterial cytoplasmic filaments in cell division requires the elucidation of the structural organization of those filamentous structures. Treponemal cytoplasmic filaments are composed of one protein, CfpA, and have been demonstrated to be involved in cell division. In this study, we used electron tomography to show that the filaments are part of a complex with a novel molecular organization that includes at least two distinct features decorating the filaments. One set of components appears to anchor the filaments to the cytoplasmic membrane. The other set of components appears to bridge the cytoplasmic filaments on the …

Integronlike Structures In Campylobacter Spp. Of Human And Animal Origin, Brigid Lucey, D. Crowley, P. Moloney, B. Cryan, M. Daly, F. O'Halloran, E. J. Threlfall, S. Fanning

Department of Biological Sciences Publications

Resistance to antimicrobial agents used to treat severe Campylobacter spp. gastroenteritis is increasing worldwide. We assessed the antimicrobial resistance patterns of Campylobacter spp. isolates of human and animal origin. More than half (n = 32) were resistant to sulphonamide, a feature known to be associated with the presence of integrons. Analysis of these integrons will further our understanding of Campylobacter spp. epidemiology.

Genetic And Structural Analyses Of Cytoplasmic Filaments Of Wild-Type Treponema Phagedenis And A Flagellar Filament-Deficient Mutant, Jacques Izard, William A. Samsonoff, Mary Beth Kinoshita, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

Unique cytoplasmic filaments are found in the treponeme genus of spirochete bacteria. Their function is unknown, but their location underneath the periplasmic flagellar filaments (PFF) suggests a role in motility and/or cell structure. To better understand these unique structures, the gene coding for the cytoplasmic filaments, cfpA, was identified in various treponemal species. Treponema phagedenis cfpA was 2,037 nucleotides long, and the encoded polypeptide showed 78 to 100% amino acid sequence identity with the partial sequence of CfpA from T. denticola, T. vincentii, and T. pallidum subsp. pertenue. Wild-type T. phagedenis and a …

Insertional Inactivation Of Treponema Denticola Tap1 Results In A Nonmotile Mutant With Elongated Flagellar Hooks, Ronald J. Limberger, Linda L. Slivienski, Jacques Izard, William A. Samsonoff

Department of Food Science and Technology: Faculty Publications

The treponemal fla operon is comprised of numerous motility-related genes; however, the initial gene of this operon, tap1, has no known function. A recently developed system to generate specific mutants in Treponema denticola was utilized to determine if Tap1 was essential for motility. T. denticola tap1 and flanking DNA were identified, cloned, and sequenced, and a suicide plasmid that contained tap1 interrupted with an erythromycin resistance cassette (ermF and ermAM) was constructed. Because of potential polar effects from this cassette, a second plasmid that contained tap1 interrupted with a modified erythromycin resistance cassette that lacked the putative ermF transcription …