A5038425461- Reproductive tract infections research
- Clostridium difficile and Clostridium perfringens research
- Gut microbiota and health
- Urinary Tract Infections Management
- Streptococcal Infections and Treatments
- Reproductive System and Pregnancy
- Bacterial Identification and Susceptibility Testing
- Escherichia coli research studies
- Cervical Cancer and HPV Research
- Antimicrobial Resistance in Staphylococcus
- Toxin Mechanisms and Immunotoxins
- Probiotics and Fermented Foods
- Pharmacological Effects of Natural Compounds
- Botulinum Toxin and Related Neurological Disorders
- Listeria monocytogenes in Food Safety
- Microscopic Colitis
- Adolescent Sexual and Reproductive Health
- Viral gastroenteritis research and epidemiology
- Biotin and Related Studies
- Bacterial Genetics and Biotechnology
- Porphyrin Metabolism and Disorders
- Essential Oils and Antimicrobial Activity
- Plant and fungal interactions
- Postharvest Quality and Shelf Life Management
- Syphilis Diagnosis and Treatment
Southern Illinois University Carbondale
2015-2024
Uniformed Services University of the Health Sciences
2007-2015
University of Pittsburgh
2004-2014
Lebanon Valley College
2003
Duquesne University
2003
University of London
1987-1989
University College London
1987-1989
The Royal Free Hospital
1987-1989
Universidad de Londres
1987
Clostridium perfringens is a Gram-positive, anaerobic spore-forming bacterium commonly found in soil, sediments, and the human gastrointestinal tract. C. responsible for wide spectrum of disease, including food poisoning, gas gangrene (clostridial myonecrosis), enteritis necroticans, non-foodborne infections. The complete genome sequences strain ATCC 13124, isolate species type strain, enterotoxin-producing poisoning SM101, were determined compared with published 13 genome. Comparison three...
Summary Clostridium perfringens type C isolates, which cause enteritis necroticans in humans and enterotoxaemias of domestic animals, typically produce (at minimum) beta toxin (CPB), alpha (CPA) perfringolysin O (PFO) during log‐phase growth. To assist development improved vaccines therapeutics, we evaluated the contribution these three toxins to intestinal virulence disease isolate CN3685. Similar natural infection, vegetative cultures wild‐type CN3685 caused haemorrhagic necrotizing rabbit...
Summary Clostridium perfringens type A isolates carrying an enterotoxin ( cpe ) gene are important cause of human gastrointestinal diseases, including food poisoning, antibiotic‐associated diarrhoea (AAD) and sporadic (SD). Using polymerase chain reaction (PCR), the current study determined that cpb2 encoding recently discovered beta2 toxin is present in <15% poisoning isolates, which typically carry a chromosomal gene. However, >75% AAD/SD usually plasmid gene, tested + by PCR....
Chlamydia trachomatis is an obligate, intracellular bacterial pathogen that has until more recently remained recalcitrant to genetic manipulation. However, the field still remains hindered by absence of tools create selectable, targeted chromosomal mutations. Previous work with mobile group II introns demonstrated they can be retargeted altering DNA sequences within intron’s substrate recognition region site-specific gene insertions. This platform (marketed as TargeTron™, Sigma) been...
In developing Clostridium perfringens as a safe vaccine vector, the alpha toxin gene (plc) in bacterial chromosome must be permanently inactivated. Disrupting genes C. by traditional mutagenesis methods is very difficult. Therefore, we developed new strategy using group II intron-based Target-Tron technology to inactivate plc ATCC 3624. Western blot analysis showed no production of protein culture supernatant mutant. Advantages this technology, such site specificity, relatively high...
The obligate intracellular human pathogen Chlamydia trachomatis (Ctr) undergoes a complex developmental cycle in which the bacterium differentiates between two functionally and morphologically distinct forms: elementary body (EB) reticulate (RB). EB is smaller, infectious, nondividing form initiates infection of susceptible host cell, whereas RB larger, non-infectious replicates within membrane-bound vesicle called an inclusion. mechanism(s) drives differentiation these forms poorly...
Bacterial AAA+ unfoldases are crucial for bacterial physiology by recognizing specific substrates and, typically, unfolding them degradation a proteolytic component. The caseinolytic protease (Clp) system is one example where hexameric unfoldase (e.g., ClpC) interacts with the tetradecameric core ClpP. Unfoldases can have both ClpP-dependent and ClpP-independent roles in protein homeostasis, development, virulence, cell differentiation. ClpC an predominantly found Gram-positive bacteria...
Enterotoxin-producing Clostridium perfringens type A isolates are an important cause of food poisoning and non-food-borne human gastrointestinal diseases, e.g., sporadic diarrhea (SPOR) antibiotic-associated (AAD). The enterotoxin gene (cpe) is usually chromosomal in but plasmid-borne AAD/SPOR isolates. Previous studies determined that SPOR isolate F5603 has a plasmid (pCPF5603) carrying cpe, IS1151, the beta2 toxin (cpb2), while F4969 (pCPF4969) lacking cpb2 IS1151 cpe IS1470-like...
The gram-positive anaerobe Clostridium perfringens produces a large arsenal of toxins that are responsible for histotoxic and enteric infections, including enterotoxemias, in humans domestic animals. C. type C isolates, which cause rapidly fatal diseases animals enteritis necroticans humans, contain the genes alpha toxin (plc), perfringolysin O (pfoA), beta (cpb), sometimes beta2 (cpb2) and/or enterotoxin (cpe). Due to economic impact C-induced diseases, commonly vaccinated with crude toxoid...
Currently, the factors/toxins responsible for Clostridium perfringens-associated avian enteritis are not well understood. To assess whether specific C. perfringens' toxinotypes associated with enteritis, isolates of perfringens from 31 cases necrotic or ulcerative submitted between 1997 and 2005 were selected retrospective analysis using multiplex PCR. was isolated chickens, turkeys, quail, psittacines. The diseased birds compared against toxinotype 19 no evidence clostridial enteritis. All...
Clostridium perfringens type C isolates cause enterotoxemias and enteritis in humans livestock. While the major disease signs lesions of are usually attributed to beta toxin (CPB), these bacteria typically produce several different lethal toxins. Since understanding pathogenesis development improved vaccines is hindered by lack small animal models mimicking lethality caused isolates, this study we developed two mouse C. C-induced lethality. When inoculated into BALB/c mice intragastric...
C hlamydia spp. are obligate, intracellular bacteria that infect humans and animals. Research on these important pathogens has been hindered due to a paucity of genetic tools. We recently adapted group II intron (GII) mutagenesis platform for creation ampicillin-selectable gene insertions in C. trachomatis L2. The aims this study were: (1) assess the stability intron-insertion an vivo infection model gauge efficacy tool long term animal studies (2) expand upon utility method by validating...
Chlamydia trachomatis is an obligate intracellular human pathogen that exhibits stage-specific gene transcription throughout a biphasic developmental cycle. The mechanisms control modulation in and associated phenotypic changes are poorly understood. This study provides evidence switch-protein kinase regulatory network controls availability of σ66, the main sigma subunit for Chlamydia. In vitro analysis revealed putative regulator, RsbW, capable interacting directly with as well...
ABSTRACT Obligate intracellular bacteria comprising the order Chlamydiales lack ability to synthesize nucleotides de novo and must acquire these essential compounds from cytosol of host cell. The environmental protozoan endosymbiont Protochlamydia amoebophila UWE25 encodes five nucleotide transporters with specificities for different substrates, including ATP, GTP, CTP, UTP, NAD. In contrast, human pathogen Chlamydia trachomatis only two transporters, ATP/ADP translocase C. Npt1 (Npt1 Ct )...
Despite having a highly reduced genome, Chlamydia trachomatis undergoes complex developmental cycle in which the bacteria differentiate between following two functionally and morphologically distinct forms: infectious, nonreplicative elementary body (EB) noninfectious, replicative reticulate (RB). The transitions EBs RBs are not mediated by division events that redistribute intracellular proteins. Rather, both primary (EB to RB) secondary (RB EB) differentiation likely require bulk protein...
Clostridium perfringens type D enterotoxemias have significant economic impact by causing rapid death of several domestic animal species. Consequently, animals are commonly vaccinated, at varying efficacy, with inactivated vegetative supernatants. Improved vaccines might become possible if the lethal toxins produced isolates were characterized and contributions those to supernatant-induced lethality established. Therefore, current study evaluated presence in supernatants prepared from...
Summary The behaviour of strains Klebsiella aerogenes capsular serotype K21 and Escherichia coli producing a structurally related polysaccharide (colanic acid) was analysed by phagocytic serum-killing assays. cell-surface characteristics these non-capsulate derived from them were also investigated partitioning experiments in aqueous two-polymer phase systems. possession K21-type capsule K. or colanic-acid E. conferred strong negative charge on capsulate bacteria. Negatively charged bacteria...
Clostridium perfringens is capable of producing up to 15 toxins, including alpha-toxin (CPA), beta-toxin (CPB), epsilon-toxin (ETX), enterotoxin, beta2-toxin (CPB2), and perfringolysin O. Type B isolates, which must produce CPA, CPB, ETX, are associated with animal illnesses characterized by sudden death or acute neurological signs, without intestinal damage. pathogenesis in ruminants poorly understood, some animals showing lesions clinical signs similar those caused either type C D...
Chlamydia spp. are obligate intracellular Gram-negative bacterial pathogens that cause disease in humans and animals. Minor variations metabolic capacity between species have been causally linked to host tissue tropisms. Analysis of the highly conserved genomes reveals divergence metabolism essential vitamin biotin with genes for either synthesis (bioF_2ADB) and/or transport (bioY). Streptavidin blotting confirmed presence a single biotinylated protein Chlamydia. As first step unraveling...
ABSTRACT The ability of Clostridium perfringens type C to cause human enteritis necroticans (EN) is attributed beta toxin (CPB). However, many EN strains also express C. enterotoxin (CPE), suggesting that CPE could be another contributor EN. Supporting this possibility, lysate supernatants from modified Duncan-Strong sporulation (MDS) medium cultures three CPE-positive caused enteropathogenic effects in rabbit small intestinal loops, which significant since produced only during and can...