A5012505852- Antimicrobial Resistance in Staphylococcus
- Escherichia coli research studies
- Bacterial Genetics and Biotechnology
- Bacterial biofilms and quorum sensing
- Urinary Tract Infections Management
- Biochemical and Structural Characterization
- Antibiotic Resistance in Bacteria
- Enterobacteriaceae and Cronobacter Research
- Bacteriophages and microbial interactions
- Salmonella and Campylobacter epidemiology
- Pediatric Urology and Nephrology Studies
- Bacterial Identification and Susceptibility Testing
- Antifungal resistance and susceptibility
- Tuberculosis Research and Epidemiology
- Listeria monocytogenes in Food Safety
- Streptococcal Infections and Treatments
- Cancer therapeutics and mechanisms
- Fungal Biology and Applications
- Viral gastroenteritis research and epidemiology
- Microbial Natural Products and Biosynthesis
- Urinary Bladder and Prostate Research
- Vibrio bacteria research studies
- Essential Oils and Antimicrobial Activity
- Clostridium difficile and Clostridium perfringens research
- Antimicrobial Peptides and Activities
University of Wisconsin–La Crosse
2013-2024
Czech Academy of Sciences, Institute of Microbiology
2006
Center for Biologics Evaluation and Research
1996-2000
Telesis Corporation (United States)
1998-1999
University of Würzburg
1994-1996
Northwestern University
1988-1994
Iowa State University
1986
The Gram-positive bacterium Staphylococcus aureus infects diverse tissues and causes a wide spectrum of diseases, suggesting that it possesses repertoire distinct molecular mechanisms promoting bacterial survival in disparate vivo environments. Signature-tag transposon mutagenesis screening 1520-member library identified numerous S. genetic loci affecting growth four complementary animal infection models including mouse abscess, bacteraemia wound rabbit endocarditis. Of total 237 attenuated...
The piliation and hemagglutination properties of 54 consecutive Escherichia coli isolates from women with recurrent urinary tract infections were studied. Mannose-sensitive (MSHA) guinea pig erythrocytes, characteristic type 1-piliated bacteria, was produced by 75% the isolates, 32% mannose-insensitive hemagglutination, 14% no reaction. production 1 pili examined in those strains that MSHA only. Studies antiserum prepared against purified suggested at least three subtypes hemagglutinins...
The role of type 1 pili and P adhesins during the in vivo growth Escherichia coli inoculated into urethras BALB/c mice was studied. Strains which produced when grown broth but lost this trait on agar (regulated variants) were tested. Broth-grown organisms colonized bladder every animal tested, with counts 10(3) to 10(4) viable recovered from homogenates. Agar-grown gave lower rates infection number bladders significantly reduced. degree inoculum piliation influenced colonization a direct...
A comparative study was performed to determine the effects of pH, osmolarity, and human urine on transcription several fim genes, as well overall expression type 1 pili. Several fim-lacZYA fusions were constructed single-copy plasmids test a range pHs osmolarities. Growth in acidic medium slightly reduced from all promoters (fimA, fimB, fimE). Increased osmolarity neutral-pH repressed fimA fimB by approximately 50% when 400 mM NaCl used nearly threefold 800 used, whereas fimE rose increased....
Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections in women, causing significant morbidity and mortality this population. Adherence to host epithelial cells a pivotal step pathogenesis UPEC. One most important virulence factors involved mediating attachment type 1 pilus (type fimbria) encoded by set fim genes arranged an operon. The expression pili controlled phenomenon known as phase variation, which reversibly switches between (Phase-ON) loss...
ABSTRACT Salmonella serovars are associated with human diseases that range from mild gastroenteritis to host-disseminated enteric fever. Human infections by enterica serovar Typhi can lead typhoid fever, but this does not typically cause disease in mice or other animals. In contrast, S. Typhimurium and Enteritidis, which usually linked localized humans some animal species, elicit a systemic infection mice. To better understand these observations, multiple strains of each several chosen were...
ABSTRACT It is not well understood why strains of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), a major cause skin and soft tissue infections, became successful so quickly, overtaking the place methicillin-sensitive S. (MSSA) in many communities. To evaluate genetic basis differences their virulence traits, 293 isolates consisting three cohorts, genotypically defined clinical CA-MRSA ( n = 77), MSSA 103), nasal carriage 113), collected over 19-year period two...
A sequencing project identified a putative copper homeostasis gene, cueA, in Pseudomonas aeruginosa strain PAO1. Strains with mutations of the cueA encoding P-type ATPase linked to P. putida, displayed greater sensitivity compared wild-type bacteria using MIC determinations and vitro passage growth media different concentrations added. An LD50 assay showed deletion mutant was 50-fold more attenuated than PAO1 bacteria. Complementation mutation restored tolerance virulence systemic model...
Staphylococcus aureus is an important pathogen of humans and other animals, causing bacteremia, abscesses, endocarditis, infectious syndromes. A signature-tagged mutagenesis (STM) system was adapted for use in studying the genes required vivo survival S. aureus. An STM library ultimately created RN6390, with Tn917 being used to create transposon mutations. Pools RN6390 mutants were screened mouse abscess, wound infection models growth attenuation after passage. One that identified displayed...
In vivo expression of pili by Escherichia coli in the urine 41 adults with lower urinary tract infections was analyzed immunostaining polyclonal antiserum to type 1 and P pili. Type were detected 31 specimens, while 6 18 specimens. The piliation status bacterial populations heterogeneous, varying from predominantly piliated a mixture nonpiliated cells. Bacteria frequently adhered exfoliated uroepithelial cells leukocytes urine. Expression did not always correlate hemagglutination phenotype...
Type 1 pili in Escherichia coli undergo phase variation which individual cells a population reversibly switch between piliated (Pil+) and nonpiliated (Pil-) states. The switching process is mediated by an invertible DNA fragment contains the promoter for fimA, gene encoding major structural subunit of type pili. Although randomly vary broth cultures, many clinical isolates E. do not express when cultured on agar media. We investigated role element upstream genes, fimB fimE, agar-mediated...
During the screening of a Staphylococcus aureus signature-tagged mutagenesis library, it was noted that nonhemolytic bacteria became more abundant as time passed in murine abscess and wound models, but not within organ tissues associated with systemic infections. To examine this further, mixed population hyperhemolytic, hemolytic, S. strain RN6390 cells were inoculated into mice using abscess, wound, models infection. After 7 days hyperhemolytic group markedly declined, whereas increased...
Anti−Bacillus cereus bioassay-guided fractionation of a crude extract the American mushroom, Fomitopsis pinicola, was performed using thin-layer chromatography, Sephadex LH-20 column and preparative-scale HPLC. Five lanostane triterpenoids (1–5) one ergostane steroid (6) were isolated identified. Compound 1 is new triterpenoid, its structure determined 1D 2D NMR experiments, HR‐MS, physical data. Each purified compounds (1–6) tested for antibacterial activity against B. standard MIC assays....
Uropathogenic Escherichia coli (UPEC) can grow in environments with significantly elevated osmolarities, such as murine and human urinary tracts. OmpR is the response regulator part of a two-component OmpR–EnvZ regulatory system that responds to osmotic stresses. To determine role UPEC survival, Δ ompR mutant was created clinical isolate NU149. The had growth defect compared wild-type strain under stress conditions; this complemented by full-length gene on plasmid, but not an alanine...
Uropathogenic Escherichia coli (UPEC) causes more than 90 % of all human urinary tract infections through type 1 piliated UPEC cells binding to bladder epithelial cells. The FimB and FimE site-specific recombinases orient the fimS element containing fimA structural gene promoter. Regulation fimB fimE depends on environmental pH osmolality. EnvZ/OmpR two-component system affects osmoregulation in E. coli. To ascertain if OmpR directly regulated promoters, gel mobility shift DNase I...
ABSTRACT Staphylococcus aureus causes a wide variety of invasive human infections. However, delineation the genes which are essential for in vivo survival this pathogen has not been accomplished to date. Using signature tag mutagenesis techniques and large mutant pool screens, previous investigators identified several major gene classes as candidate loci survival; these include amino acid transporters, oligopeptide lantibiotic synthesis (W. R. Schwan, S. N. Coulter, E. Y. W. Ng, M. H....
Blastomyces dermatitidis is the dimorphic fungal agent of blastomycosis, a disease that primarily affects humans and dogs. The clinical appearance this mycosis well characterized, but there still little known about its environmental niche, having been isolated from nature only 21 times. We have developed PCR-based assay to detect B. soil samples using primers specific portion promoter region BAD1 virulence gene. An internal standard control, pTJV2, was constructed validate results samples....
ABSTRACT The ability of Escherichia coli cells to produce type 1 pili depends upon the orientation fimA promoter. ratios FimB and FimE recombinases. Here, we report that two-component response regulator RcsB influences piliation state by controlling fimB fimE transcription.
Osmolyte transport is a pivotal part of bacterial life, particularly in high salt environments. Several low and affinity osmolyte systems have been identified various species. A lot research has centered on characterizing the Gram-negative bacteria, but less done to characterize same Gram-positive bacteria. This review will focus previous work that understand species Staphylococcus aureus how these transporters may serve dual functions allowing bacteria survive grow variety environments,...
We examined the effect of Listeria monocytogenes infection J774 macrophage-like mouse cells on induction several stress genes, including genes for heat shock proteins (HSPs) and a protein-tyrosine phosphatase (PTP), to understand host response in various steps bacterial invasion process. Exposure wild-type L. strain EGD elicited an early HSP70 mRNA with corresponding appearance protein. Cytochalasin D pretreatment prevented monocytogenes-infected macrophages. After 2-hr monocytogenes, PTP...
Staphylococcus aureus can grow virtually anywhere in the human body but needs to import proline through low- and high-affinity transporters survive. This study examined regulation of S. putP gene, which encodes a permease. putP::lacZ putP::lux transcriptional fusions were constructed integrated into genomes several strains. Enzyme activity was measured after growth media with various osmolyte concentrations. As osmolarity rose, expression increased, plateau at 2 M for NaCl strain LL3-1....