Bacteriology Commons^™

Assesment Of Antibiotic Resistant Gene Expression In Clinical Isolates Of Pseudomonas Aeruginosa, Dustin Esmond

Biology Theses

Increasing prevalence of nosocomial infections by antimicrobial resistant pathogens resulting in higher mortality rates and financial burden is of great concern. Pseudomonas aeruginosa represents one of six highly virulent “ESKAPE” pathogens that exhibit considerable intrinsic drug resistance as well as mechanisms for acquiring further resistance. As many of these mechanisms are regulated through gene expression, we sought to identify regulatory strategies and patterns at play in 23 clinical isolates collected from Baku, Azerbaijan and Tyler, Texas, USA. Real-time quantitative polymerase chain reaction was performed on six gene targets implicated in resistance and contrasted with antibiotic phenotypes. We found AmpC cephalosporinase …

Biocontrol Of Foodborne Pathogens Using Bacteriophages, Dzhuliya Ignatova, Erion Hogan, Simone Dakare, Jean Lu

Symposium of Student Scholars

Biocontrol of Foodborne Pathogens Using Bacteriophages

Dzhuliya Ignatova, Erion Hogan, Simone Dakare, and Jean Lu

Department of Molecular and Cellular Biology

Abstract

Salmonella and Shigella are two important groups of foodborne bacterial pathogens. Salmonella cause an illness called salmonellosis while Shigella cause shigellosis (bacillary dysentery). The most common symptoms of these illnesses are abdominal cramps, diarrhea, and fever. Shigella can also cause bloody diarrhea. It was estimated that each year Salmonella cause 93.8 million cases of gastroenteritis and 155,000 deaths globally. Shigella causes 164.7 million cases and 1.1 million deaths throughout the world yearly. People get these illnesses mainly by …

Examining Effects Of The Dna Regulator Lrp On Quorum Sensing Gene Expression In Pseudomonas Aeruginosa, Bradley Lumsden

Symposium of Student Scholars

Pseudomonas aeruginosa is an opportunistic human pathogen that has the capacity to express multiple virulence factors that are regulated through an extensive quorum sensing network. Three major quorum sensing systems have been identified in Pseudomonas species: the acyl homoserine lactones of las and rhl, and the Pseudomonas Quinolone Signal (PQS). We seek to investigate the involvement of a global regulator, Lrp with the expression of these three networks. Specifically, we will compare expression levels of las, rhl, and pqs in wild type P. aeruginosa (MPAO1) with an lrp transposon insertion mutant using quantitative PCR. Through this comparative …

Insights Into Halophilic Microbial Adaptation: Analysis Of Integrons And Associated Genomic Structures And Characterization Of A Nitrilase In Hypersaline Environments, Sarah Sonbol

Theses and Dissertations

Hypersaline environments are extreme habitats that can be exploited as biotechnological resources. Here, we characterized a nitrilase (NitraS-ATII) isolated from Atlantis II Deep brine pool. It showed higher thermal stability and heavy metal tolerance compared to a closely related nitrilase.

We also studied integrons in halophiles and hypersaline environments. Integrons are genetic platforms in which an integron integrase (IntI) mediates the excision and integration of gene cassettes at specific recombination sites. In order to search for integrons in halophiles and hypersaline metagenomes, we used a PCR-based approach, in addition to different bioinformatics tools, mainly IntegronFinder.

We found that integrons and …

The Staphylococcus Aureus Lrgab Operon Encodes A Holin-Like Protein Involved In Pyruvate Transport, Jennifer L. Endres

Theses & Dissertations

The Staphylococcus aureus cidABC and lrgAB operons encode a well-conserved family of proteins involved in programmed cell death (PCD) during biofilm development. Based on the structural similarities that CidA and LrgA share with bacteriophage holins, we have hypothesized that these proteins function by forming pores within the cytoplasmic membrane. To test this, we utilized a “lysis cassette” system that demonstrated the abilities of the cidA and lrgA genes to support bacteriophage endolysin-induced cell lysis. In addition, the CidA and LrgA proteins were shown to localize to the surface of membrane vesicles and cause leakage of small molecules, providing direct evidence …

Role Of A Cryptic Trna Gene Operon In Survival Under Translational Stress, Javier Santamaría-Gómez, Miguel Ángel Rubio, Rocío López-Igual, Ana B. Romero-Losada, Fernando M. Delgado-Chaves, Roque Bru-Martínez, Francisco J. Romero-Campero, Antonio Herrero, Michael Ibba, Jesús A. G. Ochoa De Alda, Ignacio Luque

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

As compared to eukaryotes, bacteria have a reduced tRNA gene set encoding between 30 and 220 tRNAs. Although in most bacterial phyla tRNA genes are dispersed in the genome, many species from distinct phyla also show genes forming arrays. Here, we show that two types of arrays with distinct evolutionary origins exist. This work focuses on long tRNA gene arrays (L-arrays) that encompass up to 43 genes, which disseminate by horizontal gene transfer and contribute supernumerary tRNA genes to the host. Although in the few cases previously studied these arrays were reported to be poorly transcribed, here we show that …

You Are What You Eat — Exploring The Microbiome Through Inquiry-Based Labs. Microbiome Lesson Plans, Karla S. Fuller

Open Educational Resources

If these commonly used spices have the ability to inhibit pathogenic bacterial growth, could they also potentially inhibit the growth of normal, harmless bacteria that live in your body? In this lab, we will test common bacteria for resistance to food additives.

Antibacterial Properties Of Citric Acid/Β-Alanine Carbon Dots Against Gram-Negative Bacteria, Anju Pandey, Asmita Devkota, Zeinab Yadegari, C. Korsi Dumenyo, Ali Taheri

Agricultural and Environmental Sciences Faculty Research

While multi-drug resistance in bacteria is an emerging concern in public health, using carbon dots (CDs) as a new source of antimicrobial activity is gaining popularity due to their antimicrobial and non-toxic properties. Here we prepared carbon dots from citric acid and β-alanine and demonstrated their ability to inhibit the growth of diverse groups of Gram-negative bacteria, including E. coli, Salmonella, Pseudomonas, Agrobacterium, and Pectobacterium species. Carbon dots were prepared using a one-pot, three-minute synthesis process in a commercial microwave oven (700 W). The antibacterial activity of these CDs was studied using the well-diffusion method, and their minimal inhibitory concentration …

The Role Of The Msaabcr Operon In Cell Wall Integrity And Programmed Cell Death During Biofilm Development, Bibek G C

Dissertations

Staphylococcus aureus is an important human pathogen in both community and health care settings. Biggest challenges with S. aureus as a pathogen is its ability to acquire antibiotic resistance and produce robust biofilms. In this work, we investigated the nature of the cell wall defect in the msaABCR operon mutant in the Mu50 (VISA) and USA300 LAC methicillin-resistant Staphylococcus aureus (MRSA) strains. Results showed that msaABCR-mutant cells had decreased cell wall thickness and cell wall crosslinking in both strains. These defects are most likely due to increased murein hydrolase activity and/or nonspecific processing of murein hydrolases mediated by increased …

Calibration Study Of A Bacterial Quantification Technique Using Transport Swabs And Line Inoculations On Agar Growth Medium, Seth Larue

Honors Theses

Enumeration of bacteria has been the subject of research for over a century. Some of the techniques that have been developed include viable plate counts, the most probable number assessment, and more modern molecular techniques. Many of the newer molecular-based techniques provide little or no information about the viability of the cells being counted, and are generally not quantitative. Having quantitative data for potentially pathogenic bacteria on surfaces can be very useful in many settings, particularly in healthcare facilities. Knowing the numbers of bacterial cells present on surfaces within healthcare facilities may be important to attempt to study the cause …

Directed Genome Evolution To Identify Genes For Macrophage Survival By Staphylococcus Agnetis, Sonali Lakshika Anne Lenaduwe Lokuge

Graduate Theses and Dissertations

Bacterial Chondronecrosis with Osteomyelitis (BCO) is a debilitating infection that negatively impacts animal welfare and costs the broiler industry billions of dollars annually. We have previously isolated Staphylococcus agnetis 908 from BCO samples obtained from broilers at the University of Arkansas research farm. This isolate can induce BCO lameness at greater than 50% in broilers exposed to the pathogen in drinking water. We found that S. agnetis 908 is capable of surviving and escaping macrophages compared to a closely related cattle isolate,1379. Through Directed Genome Evolution (DGE) we identified that this difference is at least partially associated with an alanine …

A Bacterial Inflammation Sensor Regulates C-Di-Gmp Signaling, Adhesion, And Biofilm Formation, Arden Perkins, Dan A. Tudorica, Raphael D. Teixeira, Tilman Schirmer, Lindsay Zumwalt, O. Maduka Ogba, C. Keith Cassidy, Phillip J. Stansfeld, Karen Guillemin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Bacteria that colonize animals must overcome, or coexist, with the reactive oxygen species products of inflammation, a front-line defense of innate immunity. Among these is the neutrophilic oxidant bleach, hypochlorous acid (HOCl), a potent antimicrobial that plays a primary role in killing bacteria through nonspecific oxidation of proteins, lipids, and DNA. Here, we report that in response to increasing HOCl levels, Escherichia coli regulates biofilm production via activation of the diguanylate cyclase DgcZ. We identify the mechanism of DgcZ sensing of HOCl to be direct oxidation of its regulatory chemoreceptor zinc-binding (CZB) domain. Dissection of CZB signal transduction reveals that …

Deacylated Trna Accumulation Is A Trigger For Bacterial Antibiotic Persistence Independent Of The Stringent Response, Whitney N. Wood, Kyle Mohler, Jesse Rinehart, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Bacterial antibiotic persistence occurs when bacteria are treated with an antibiotic and the majority of the population rapidly dies off, but a small subpopulation enters into a dormant, persistent state and evades death. Diverse pathways leading to nucleoside triphosphate (NTP) depletion and restricted translation have been implicated in persistence, suggesting alternative redundant routes may exist to initiate persister formation. To investigate the molecular mechanism of one such pathway, functional variants of an essential component of translation (phenylalanyltRNA synthetase [PheRS]) were used to study the effects of quality control on antibiotic persistence. Upon amino acid limitation, elevated PheRS quality control led …

Prophylactic Phage Therapy In Infant Rabbits Model Of Cholera, Sadeq Ag Kaabi Asst Prof Dr

Karbala International Journal of Modern Science

A number of 8 phages lytic of V. cholerae O1- biotype-EI-Tor, serotype Inaba were selected for the formulation of a phage cocktail. A phage cocktail composed of 8 phages was prepared and showed 100% inhibition of V. cholerae isolates comparing with a percentage ranged from 0-75% for every single phage in growth inhibition assay. The potential activity of phage cocktail of prophylactic therapy for infant rabbits model of cholera was evaluated through phage retention time and length of phage prophylaxis studies. Results have been showed that phage cocktail was potent in the prevention of development of cholera in infant rabbits …

Non-B Dna-Forming Motifs Promote Mfd-Dependent Stationary-Phase Mutagenesis In Bacillus Subtilis, Tatiana Ermi, Carmen Vallin, Ana Gabriela Regalado García, Moises Bravo, Ismaray Fernandez Cordero, Holly Anne Martin, Mario Pedraza-Reyes, Eduardo Robleto

Life Sciences Faculty Research

Transcription-induced mutagenic mechanisms limit genetic changes to times when expression happens and to coding DNA. It has been hypothesized that intrinsic sequences that have the potential to form alternate DNA structures, such as non-B DNA structures, influence these mechanisms. Non-B DNA structures are promoted by transcription and induce genome instability in eukaryotic cells, but their impact in bacterial genomes is less known. Here, we investigated if G4 DNA-and hairpin-forming motifs influence stationary-phase mutagenesis in Bacillus subtilis. We developed a system to measure the influence of non-B DNA on B. subtilis stationary-phase mutagenesis by deleting the wild-type argF at its chromosomal …

Draft Genome Sequences Of 13 Vibrio Cholerae Strains From The Rio Grande Delta, Jeffrey W. Turner, Jorge Duran-Gonzalez, David A. Laughlin, Daniel Unterweger, David Silva, Boris Ermolinsky, Stefan Pukatzki, Daniele Provenzano

Publications and Research

Vibrio cholerae is the etiologic agent of cholera, an acute and often fatal diarrheal disease that affects millions globally. We report the draft genome sequences of 13 non-O1/O139 V. cholerae strains isolated from the Rio Grande Delta in Texas. These genomes will aid future analyses of environmental serovars.

Antibiotic Resistance In Mucosal Bacteria From High Arctic Migratory Salmonids, Kristy Moniz, Virginia K. Walker, Vishal Shah

Biology Faculty Publications

Two related salmonids, Arctic char (Salvelinus alpinus) and lake whitefish (Coregonus clupeaformis) sampled from the high Arctic region of Nunavut, Canada are anadromous fish, migrating annually from the same ice-covered freshwater waterbodies to spend summers in the marine waters of the Arctic Ocean. Microbiota associated with the skin-associated mucus undergo community change coincident with migration, and irrespective of this turnover, antibiotic resistance was detected in mixed bacterial cultures initiated with mucus samples. Although as expected most bacteria were unculturable, however, 5/7 isolates showed susceptibility to a panel of five common antibiotics. The fish were sampled under severe conditions and at …

Investigating Distribution Of Legionella Pneumophila In Urban And Suburban Watersheds, Azlan Maqbool

Student Theses

The presence of Legionella pneumophila was assessed using a cultivation-based approach in New York City waterways, a freshwater portion of the lower Hudson River Estuary near Kingston NY, and in urban and suburban street water. Legionella pneumophila was detected in 51% of brackish New York City Estuary samples, most with concentrations near minimum detection (=>1 organism/ mL). In contrast, it was detected in 22% of suburban freshwater Hudson River Estuary samples. Levels of the bacterium were found to be higher during wet weather compared to dry weather in the highly dense urban setting, but not in the less dense …

Design, Synthesis, And Evaluation Of Carbapenem And Cephalosporin Antibiotics To Counter Resistant 21st Century Pathogens, Maha Alqurafi

Chemistry Theses and Dissertations

Antibiotics represent one of mankind’s most important discoveries, enabling longer, more productive lives. Carbapenem antibiotics are one of the most potent classes of β-lactams and often represent the last resort used to treat patients who are seriously stricken by bacterial infections. Carbapenems possess a broad spectrum of antibacterial activity including efficacy against the majority of Gram-positive and Gram–negative bacteria. Unfortunately, the emergence of antibiotic resistant strains is posing a serious threat to existing antibiotics. New discoveries in the antibiotic field are desperately needed to counter the threat of rapidly evolving bacterial resistance. Despite the investment of billions of dollars, and …

Role And Regulation Of Staphylococcal Cell Death, Abdulelah Ahmed Alqarzaee S

Theses & Dissertations

The transition from growth to stationary phase is a natural response of bacteria to starvation and stress. When stress is alleviated and more favorable growth conditions return, bacteria resume proliferation without a significant loss in fitness. Although specific adaptations that enhance persistence and survival of bacteria in stationary phase have been identified, mechanisms that help maintain the competitive fitness potential of non-dividing bacterial populations have remained obscure. This dissertation demonstrates that staphylococci entering stationary phase following growth in excess glucose undergo regulated cell death to maintain the competitive fitness potential of the population. Upon a decrease in extracellular pH, the …