Genetic diversity and known virulence genes in strains isolated from cattle abortions and farm environment.

is considered as non-pathogenic bacteria living in an environment although several cases of immunocompromised humans and ruminant listeriosis infections have been reported. Previously, L. was identified as a potential pathogen and virulence in association with L.

Prevalence, virulence determinants, and genetic diversity in Yersinia enterocolitica isolated from slaughtered pigs and pig carcasses.

Yersinia enterocolitica is an important zoonotic foodborne pathogen that could be transferred from infected pigs to their carcasses at slaughter, with subsequent introduction of the pathogen into the food chain. The aim of the present study was to study the prevalence, virulence characteristics, and genetic diversity of Y. enterocolitica isolates present in slaughtered pig tonsils and carcasses by using the WGS approach.

Virulence Determinants and Genetic Diversity of Species Isolated from Retail Meat.

is an important foodborne pathogen, and the determination of its virulence factors and genetic diversity within the food chain could help understand the epidemiology of yersiniosis. The aim of the present study was to detect the prevalence, and characterize the virulence determinants and genetic diversity, of species isolated from meat. A total of 330 samples of retailed beef (n = 150) and pork (n = 180) in Latvia were investigated with culture and molecular methods.

Characterization and Genetic Diversity of Isolated from Cattle Abortions in Latvia, 2013-2018.

can cause disease in humans and in a wide range of animal species, especially in farm ruminants. The aim of the study was to determine the prevalence and genetic diversity of related to 1185 cattle abortion cases in Latvia during 2013-2018. The prevalence of among cattle abortions was 16.

Development of a Novel Method for Identification of Mesocercariae by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry.

() mesocercariae (AM) have increasingly appeared as incidental findings during the mandatory inspection of wild boars for in many European countries. An spp.-specific PCR is available for the identification of AM; however, it is time- and cost-intensive.

Prevalence, Genetic Diversity and Factors Associated with Distribution of and Other spp. in Cattle Farms in Latvia.

spp. is a diverse genus of Gram-positive bacteria commonly present in the environment while and are well known human and ruminant pathogens. The aim of the present study was to reveal the prevalence and genetic diversity of and other spp.

Determination of Fungi and Multi-Class Mycotoxins in and Herbal Teas and Dietary Exposure Assessment.

In this paper, a study of fungal and multi-mycotoxin contamination in 140 and 26 herbal teas marketed in Latvia is discussed. The analysis was performed using two-dimensional liquid chromatography with time-of-flight mass spectrometry (2D-LC-TOF-MS) and MALDI-TOF-MS. In total, 87% of the tea samples tested positive for 32 fungal species belonging to 17 genera, with the total enumeration of moulds ranging between 1.

Determination of methicillin-resistant and by MALDI-TOF MS in clinical isolates from Latvia.

Rapid identification of methicillin-resistant could ensure appropriate medical care. A total of 409 spp. strains were used to develop a reliable MALDI-TOF method for species identification.

Occurrence of Pathogenic and Potentially Pathogenic Bacteria in Microgreens, Sprouts, and Sprouted Seeds on Retail Market in Riga, Latvia.

Microgreens and sprouts have been used for raw consumption for a long time and are generally viewed as a healthy food. However, several serious outbreaks of foodborne illness have been recorded in European countries, Japan, and North America. Many companies in Latvia nowadays are producing this type of products.

species prevalence, characterisation of antimicrobial resistance and analysis of whole-genome sequence of isolates from livestock and humans, Latvia, 2008 to 2016.

Background is the main cause of bacterial gastroenteritis worldwide. The main transmission route is through consumption of food contaminated with species or contact with infected animals. In Latvia, the prevalence of campylobacteriosis is reported to be low (4.

Target-based antimicrobial drug discovery.

The continued increase in antibiotic resistance among bacterial pathogens, coupled with a decrease in infectious disease research among pharmaceutical companies, has escalated the need for novel and effective antibacterial chemotherapies. While current agents have emerged almost exclusively from whole-cell screening of natural products and small molecules that cause microbial death, recent advances in target identification and assay development have resulted in a flood of target-driven drug discovery methods. Whether genome-based methodologies will yield new classes of agents that conventional methods have been unable to is yet to be seen.

Development of an HPLC assay for Staphylococcus aureus sortase: evidence for the formation of the kinetically competent acyl enzyme intermediate.

Many bacterial surface proteins containing an LPXTG motif are anchored to the cell wall peptidoglycan by catalysis with the thiol transpeptidase sortase. The transpeptidation and hydrolysis reactions of sortase have been proposed to proceed through a common acyl enzyme intermediate. The reactions of Staphylococcus aureus sortase with fluorogenic substrate Abz-LPETG-Dnp in the presence or absence of triglycine were characterized in this study to gain additional insight into the kinetic mechanism of sortase.

Effect of srtA and srtB gene expression on the virulence of Staphylococcus aureus in animal models of infection.

Objective: The role that the surface proteins anchored by the srtA and srtB gene products play in the ability of Staphylococcus aureus bacteria to establish infection was investigated in several animal models.

Methods: Wild-type and corresponding mutants with deletions of the srtA and/or srtB genes were used in murine acute lethal infection, septic arthritis, kidney infection and rat endocarditis models.

Results: The LD(50) of the wild-type and srtB- knockout were comparable and approximately two- to four-fold lower than the required inoculum of the srtA- and srtA-B- strains.

Kinetic mechanism of Staphylococcus aureus sortase SrtA.

Staphylococcus aureus sortase (SrtA) is a thiol transpeptidase. The enzyme catalyzes a cell wall sorting reaction in which a surface protein with a sorting signal containing a LPXTG motif is cleaved between the threonine and glycine residues. The resulting threonine carboxyl end of this protein is covalently attached to a pentaglycine cross-bridge of peptidoglycan.

Balofloxacin Choongwae.

Balofloxacin, an orally active fluoroquinolone antibiotic, has been developed by Choongwae Pharma in Korea, for the treatment of urinary tract infection (UTI). Chugai and Ciba were developing balofloxacin for respiratory tract infections (RTI) but discontinued development in 1995 due to changes in Chugai's R&D focus and a lack of efficacy of the drug. Following phase II trials, Choongwae bought the rights to develop balofloxacin in Korea from Chugai.

Virulence as a target for antimicrobial chemotherapy.

Bacterial resistance to present day antibiotics has become a dangerous threat to public health. Consequently, the pharmaceutical industry must provide new agents and novel classes to combat bacterial disease and to stay a step ahead of the rapid evolution of bacterial resistance mechanisms. The need for novel antibacterials has resulted in a search for previously unexplored targets for chemotherapy, utilising the new techniques of genomics to identify them.

Genomics in anti-infective drug discovery--getting to endgame.

Whole chromosome sequence of prokaryotes has provided the availability of multiple bacterial pathogen sequence data and it has become a widely used tool in the drug discovery process. However the sequence data in itself is merely a starting point for drug discovery of novel antibacterial targets and, eventually, drugs. In order to leverage this large amount of data it is necessary to match an understanding of the microbial physiology of pathogenic bacteria to disease processes and identifying the gene products for which intervention may reduce or eliminate the infectious state.

Anchoring of surface proteins to the cell wall of Staphylococcus aureus. Cysteine 184 and histidine 120 of sortase form a thiolate-imidazolium ion pair for catalysis.

Surface proteins of Staphylococcus aureus are anchored to the cell wall peptidoglycan by a mechanism requiring a C-terminal sorting signal with a LPXTG motif. Sortase cleaves polypeptides between the threonine and the glycine of the LPXTG motif. The carboxyl group of threonine is subsequently amide-linked to the amino group of peptidoglycan cross-bridges.

Bacterial virulence as a target for antimicrobial chemotherapy.

As bacterial resistance to currently used antibiotics increases, so too must efforts to identify novel agents and strategies for the prevention and treatment of bacterial infection. In the past, antimicrobial drug discovery efforts have focused on eradicating infection by either cidal or static agents, resulting in clearance of the bacterium from the infected host. To this end, drug discovery targets have been those proteins or processes essential for bacterial cell viability.

Identification and analysis of bacterial protein secretion inhibitors utilizing a SecA-LacZ reporter fusion system.

Protein secretion is an essential process for bacterial growth, yet there are few if any antimicrobial agents which inhibit secretion. An in vivo, high-throughput screen to detect secretion inhibitors was developed based on the translational autoregulation of one of the central protein components, SecA. The assay makes use of a SecA-LacZ fusion reporter construct in Escherichia coli which is induced when secretion is perturbed.

Expression of the AsbA1, OXA-12, and AsbM1 beta-lactamases in Aeromonas jandaei AER 14 is coordinated by a two-component regulon.

Aeromonas jandaei AER 14 (formerly Aeromonas sobria AER 14) expresses three inducible beta-lactamases, AsbA1, OXA-12 (AsbB1), and AsbM1. Mutant strains that constitutively overexpress all three enzyme simultaneously, suggesting that they share a common regulatory pathway, have been isolated. Detectable expression of the cloned genes of AsbA1 and OXA-12 in some Escherichia coli K-12 laboratory strains is achieved only in the presence of a blp mutation.

Mutations in yeast ribosomal proteins S28 and S4 affect the accuracy of translation and alter the sensitivity of the ribosomes to paromomycin.

Ribosomal proteins S12, S5 and S4 of Escherichia coli are essential for the control of translational accuracy. Their yeast equivalents, i.e.

A mutation in either dsbA or dsbB, a gene encoding a component of a periplasmic disulfide bond-catalyzing system, is required for high-level expression of the Bacteroides fragilis metallo-beta-lactamase, CcrA, in Escherichia coli.

The metallo-beta-lactamase gene, ccrA, from Bacteroides fragilis is functionally expressed in Escherichia coli only in the presence of a genomic mutation in iarA or iarB (increased ampicillin resistance), identified in this study as dsbA or dsbB, respectively. DsbA and DsbB are components of a periplasmic protein disulfide bond-catalyzing system. Data indicated that DsbA interacted with CcrA, creating aberrant disulfide bond linkages that render CcrA proteolytically unstable.

An accuracy center in the ribosome conserved over 2 billion years.

The accuracy of translation in Escherichia coli is profoundly influenced by three interacting ribosomal proteins, S12, S4, and S5. Mutations at lysine-42 of S12, originally isolated as causing resistance to streptomycin, increase accuracy. Countervailing "ribosomal ambiguity mutations" (ram) in S4 or S5 decrease accuracy.

A novel cloning strategy reveals the gene for the yeast homologue to Escherichia coli ribosomal protein S12.

Using a novel technique designed to identify genes of Saccharomyces cerevisiae which carry introns, we have cloned two genes encoding ribosomal protein S28. Although the genes differ by 15 nucleotides within their coding regions, they are predicted to encode identical proteins of 145 amino acids. The predicted amino acid sequence of S28 contains significant homology to ribosomal protein S25 of Tetrahymena thermophila and to ribosomal protein S12 of several archaebacteria, suggesting a relationship to S12 of Escherichia coli.