Hepatobiliary Helicobacters: recognized animal pathogens with suspected pathogenic potential in humans

2000 ◽  
pp. 83-104 ◽  
Author(s):  
J. G. Fox
Keyword(s):  
Pathogenic Potential ◽  
Animal Pathogens

scholarly journals Chlamydia gallinacea: genetically armed as a pathogen however a phenotypical commensal?

2020 ◽  
Author(s):  
Marloes Heijne ◽  
Martina Jelocnik ◽  
Alexander Umanets ◽  
Michael S.M. Brouwer ◽  
Annemieke Dinkla ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Clinical Signs ◽  
Chlamydia Psittaci ◽  
Pathogenic Potential ◽  
Animal Pathogens ◽  
The Family ◽  
Chicken Eggs ◽  
Sequence Types ◽  
Embryonated Chicken ◽  
Infection Experiments

AbstractChlamydia gallinacea is an obligate intracellular bacterium that has recently been added to the family of Chlamydiaceae. C. gallinacea is genetically diverse, widespread in poultry and a suspected cause of pneumonia in slaughterhouse workers. In poultry, C. gallinacea infections appear asymptomatic, but studies about the pathogenic potential are limited. In this study two novel sequence types of C. gallinacea were isolated from apparently healthy chickens. Both isolates (NL_G47 and NL_F725) were closely related to each other and showed 99.1% DNA sequence identity to C. gallinacea Type strain 08-1274/3. To gain further insight in the pathogenic potential, infection experiments in embryonated chicken eggs and comparative genomics with Chlamydia psittaci were performed. C. psittaci is an ubiquitous zoonotic pathogen of birds and mammals, and infection in poultry can result in severe systemic illness. In experiments with embryonated chicken eggs C. gallinacea induced mortality was observed, potentially strain dependent but lower compared to C. psittaci induced mortality. Comparative analyses confirmed all currently available C. gallinacea genomes possess the hallmark genes coding for known and potential virulence factors as found in C. psittaci albeit to a reduced number of orthologues or paralogs. The presence of (potential) virulence factors and the observed mortality in embryonated eggs indicates C. gallinacea should rather be considered as a (conditional) pathogen than an innocuous commensal.ImportanceChlamydiaceae are a family of bacteria comprising human and animal pathogens including the recently recognized Chlamydia gallinacea. C. gallinacea is widespread in poultry without causing clinical signs, which raises questions about its pathogenic potential. To assess this potential, two novel C. gallinacea strains were isolated, tested in infection experiments in embryonated chicken eggs and compared to C. psittaci. C. psittaci infection in poultry can result in severe systemic illness, depending on the conditions, and infections can be transmitted to humans. In the experiments C. gallinacea infection induced mortality of the embryo, but to a lower extent than infection with C. psittaci. Subsequent genome comparisons confirmed both C. gallinacea strains possess potential virulence genes typical for chlamydia, but fewer than C. psittaci. These results indicate C. gallinacea does have a pathogenic potential which warrants further research to elucidate its role as a poultry pathogen.

scholarly journals Staphylococcus ratti sp. nov. Isolated from a Lab Rat

Pathogens ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 51
Author(s):  
Vojtěch Kovařovic ◽  
Ivo Sedláček ◽  
Petr Petráš ◽  
Stanislava Králová ◽  
Ivana Mašlaňová ◽  
...  
Keyword(s):  
Species Group ◽  
Genomic Islands ◽  
Laboratory Animals ◽  
16S Rrna Sequence ◽  
Pathogenic Potential ◽  
Staphylococcus Intermedius ◽  
Animal Pathogens ◽  
Expert Annotation ◽  
Causative Agents ◽  
Taxonomic Approach

Staphylococci from the Staphylococcus intermedius-Staphylococcus hyicus species group include numerous animal pathogens and are an important reservoir of virulence and antimicrobial resistance determinants. Due to their pathogenic potential, they are possible causative agents of zoonoses in humans; therefore, it is important to address the properties of these strains. Here we used a polyphasic taxonomic approach to characterize the coagulase-negative staphylococcal strain NRL/St 03/464T, isolated from the nostrils of a healthy laboratory rat during a microbiological screening of laboratory animals. The 16S rRNA sequence, MALDI-TOF mass spectrometry and positive urea hydrolysis and beta-glucuronidase tests clearly distinguished it from closely related Staphylococcus spp. All analyses have consistently shown that the closest relative is Staphylococcus chromogenes; however, values of digital DNA-DNA hybridization <35.3% and an average nucleotide identity <81.4% confirmed that the analyzed strain is a distinct Staphylococcus species. Whole-genome sequencing and expert annotation of the genome revealed the presence of novel variable genetic elements, including two plasmids named pSR9025A and pSR9025B, prophages, genomic islands and a composite transposon that may confer selective advantages to other bacteria and enhance their survival. Based on phenotypic, phylogenetic and genomic data obtained in this study, the strain NRL/St 03/464T (= CCM 9025T = LMG 31873T = DSM 111348T) represents a novel species with the suggested name Staphylococcus ratti sp. nov.

scholarly journals Pathogenic Potential of Novel Chlamydiae and Diagnostic Approaches to Infections Due to These Obligate Intracellular Bacteria

2006 ◽  
Vol 19 (2) ◽  
pp. 283-297 ◽  
Author(s):  
Daniele Corsaro ◽  
Gilbert Greub
Keyword(s):  
Mammalian Cell Culture ◽  
Host Cells ◽  
The Novel ◽  
Human Pathogens ◽  
Pathogenic Potential ◽  
Obligate Intracellular ◽  
Animal Pathogens ◽  
Diagnostic Approaches ◽  
Obligate Intracellular Bacteria ◽  
Simkania Negevensis

SUMMARY Novel chlamydiae are newly recognized members of the phylum Chlamydiales that are only distantly related to the classic Chlamydiaceae, i.e., Chlamydia and Chlamydophila species. They also exibit an obligate biphasic intracellular life cycle within eukaryote host cells. Some of these new chlamydiae are currently considered potential emerging human and/or animal pathogens. Parachlamydia acanthamoebae and Simkania negevensis are both emerging respiratory human pathogens, Waddlia chondrophila could be a novel abortigenic bovine agent, and Piscichlamydia salmonis has recently been identified as an agent of the gill epitheliocystis in the Atlantic salmon. Fritschea spp. and Rhabdochlamydia spp. seem to be confined to arthropods, but some evidence for human exposure exists. In this review, we first summarize the data supporting a pathogenic potential of the novel chlamydiae for humans and other vertebrates and the interactions that most of these chlamydiae have with free-living amoebae. We then review the diagnostic approaches to infections potentially due to the novel chlamydiae, especially focusing on the currently available PCR-based protocols, mammalian cell culture, the amoebal coculture system, and serology.

Questions on the role of biofilms for the adaptation of microorganisms to unfavorable environmental factors by the example of P. aeruginosa

2020 ◽  
Vol 99 (4) ◽  
pp. 379-383
Author(s):  
Vasily N. Afonyushkin ◽  
N. A. Donchenko ◽  
Ju. N. Kozlova ◽  
N. A. Davidova ◽  
V. Yu. Koptev ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Environmental Factors ◽  
Barrier Function ◽  
Infectious Agent ◽  
Antagonistic Activity ◽  
The Body ◽  
Main Function ◽  
Pathogenic Potential ◽  
The Face

Pseudomonas aeruginosa is a widely represented species of bacteria possessing of a pathogenic potential. This infectious agent is causing wound infections, fibrotic cystitis, fibrosing pneumonia, bacterial sepsis, etc. The microorganism is highly resistant to antiseptics, disinfectants, immune system responses of the body. The responses of a quorum sense of this kind of bacteria ensure the inclusion of many pathogenicity factors. The analysis of the scientific literature made it possible to formulate four questions concerning the role of biofilms for the adaptation of P. aeruginosa to adverse environmental factors: Is another person appears to be predominantly of a source an etiological agent or the source of P. aeruginosa infection in the environment? Does the formation of biofilms influence on the antibiotic resistance? How the antagonistic activity of microorganisms is realized in biofilm form? What is the main function of biofilms in the functioning of bacteria? A hypothesis has been put forward the effect of biofilms on the increase of antibiotic resistance of bacteria and, in particular, P. aeruginosa to be secondary in charcter. It is more likely a biofilmboth to fulfill the function of storing nutrients and provide topical competition in the face of food scarcity. In connection with the incompatibility of the molecular radii of most antibiotics and pores in biofilm, biofilm is doubtful to be capable of performing a barrier function for protecting against antibiotics. However, with respect to antibodies and immunocompetent cells, the barrier function is beyond doubt. The biofilm is more likely to fulfill the function of storing nutrients and providing topical competition in conditions of scarcity of food resources.

Pathogenic potential of Parabacteroides distasonis revealed in a splenic abscess case: a truth unfolded

2020 ◽  
Vol 13 (12) ◽  
pp. e236701
Author(s):  
Anitha Gunalan ◽  
Rakhi Biswas ◽  
Balamurugan Sridharan ◽  
Thirthar Palanivelu Elamurugan
Keyword(s):  
Abdominal Pain ◽  
Case Report ◽  
Antimicrobial Therapy ◽  
Splenic Abscess ◽  
Rare Entity ◽  
Normal Flora ◽  
Pathogenic Role ◽  
Pathogenic Potential ◽  
Open Splenectomy

Splenic abscess is a rare entity, however if unrecognised or left untreated, it is invariably fatal. We herein report a case of splenic abscess in a 40-year-old man presenting with fever, left-sided abdominal pain, altered sensorium and vomiting. On clinical examination, hepatosplenomegaly was noted and the ultrasound of the abdomen showed multiple hypoechoic regions in the upper pole of spleen, and the diagnosis of splenic abscess was made. The patient received antimicrobial therapy and underwent an open splenectomy with full recovery. Pus aspirated from the splenic abscess grew an unusual organism named Parabacteroides distasonis. In the literature, there are only a few recorded cases of P. distasonis causing splenic abscess. Through this case report, we would like to emphasise the pathogenic role of P. distasonis in causing clinical disease, as this organism is typically known to constitute a part of the normal flora.

scholarly journals Detection of three pandemic causing coronaviruses from non-respiratory samples: systematic review and meta-analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chandan Mishra ◽  
Suneeta Meena ◽  
Jitendra Kumar Meena ◽  
Suman Tiwari ◽  
Purva Mathur
Keyword(s):  
Systematic Review ◽  
Detection Rate ◽  
Meta Analysis ◽  
Total Sample ◽  
Urine Samples ◽  
Pathogenic Potential ◽  
Clinical Specimens ◽  
Qrt Pcr ◽  
Corona Virus ◽  
Positive Rate

AbstractSARS-CoV-2 has posed an unprecedented challenge to the world. Pandemics have been caused previously by viruses of this family like Middle East Respiratory Corona Virus (MERS CoV), Severe Acute Respiratory Syndrome Corona Virus (SARS CoV). Although these viruses are primarily respiratory viruses, but they have been isolated from non-respiratory samples as well. Presently, the detection rate of SARS‐CoV‐2 RNA from different clinical specimens using Real Time Reverse Transcriptase Polymerized Chain Reaction (qRT‐PCR) after onset of symptoms is not yet well established. Therefore, the aim of this systematic review was to establish the profile of detecting SARS‐CoV‐2, MERS CoV, SARS CoV from different types of clinical specimens other than the respiratory using a standard diagnostic test (qRT‐PCR). A total of 3429 non-respiratory specimens were recorded: SARS CoV (total sample—802), MERS CoV (total sample—155), SARS CoV-2 (total sample—2347). Out of all the samples studied high positive rate was seen for saliva with 96.7% (14/14; 95% CI 87.6–100.0%) for SARS CoV and 57.5% (58/250; 95% CI − 1.2 to 116.2%) for SARS CoV-2, while low detection rate in urine samples for SARS CoV-2 with 2.2% (8/318; 95% CI 0.6–3.7%) and 9.6% (12/61; 95% CI − 0.9 to 20.1%) for SARS CoV but there was relatively higher positivity in urine samples for MERS CoV with detection rate of 32.4% (2/38; 95% CI − 37.3 to 102.1%). In Stool sample positivity was 54.9% (396/779; 95% CI 41.0–68.8%), 45.2% (180/430; 95% CI 28.1–62.3%) and 34.7% (4/38; 95% CI − 29.5 to 98.9%) for SARS CoV-2, MERS CoV, and SARS CoV, respectively. In blood sample the positivity was 33.3% (7/21; 95% CI 13.2–53.5%), 23.7% (42/277; 95% CI 10.5–36.9%) and 2.5% (2/81; 95% CI 0.00–5.8%) for MERS CoV, SARS CoV-2 and SARS CoV respectively. SARS‐CoV‐2 along with previous two pandemic causing viruses from this family, were highly detected stool and saliva. A low positive rate was recorded in blood samples. Viruses were also detected in fluids along with unusual samples like semen and vaginal secretions thus highlighting unique pathogenic potential of SARS‐CoV‐2.

scholarly journals ITN—VIROINF: Understanding (Harmful) Virus-Host Interactions by Linking Virology and Bioinformatics

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 766
Author(s):  
Winfried Goettsch ◽  
Niko Beerenwinkel ◽  
Li Deng ◽  
Lars Dölken ◽  
Bas E. Dutilh ◽  
...  
Keyword(s):  
Control Strategies ◽  
Fundamental Importance ◽  
Viral Growth ◽  
International Training ◽  
Host Interactions ◽  
Animal Pathogens ◽  
Interdisciplinary Nature ◽  
Common Goals

Many recent studies highlight the fundamental importance of viruses. Besides their important role as human and animal pathogens, their beneficial, commensal or harmful functions are poorly understood. By developing and applying tailored bioinformatical tools in important virological models, the Marie Skłodowska-Curie Initiative International Training Network VIROINF will provide a better understanding of viruses and the interaction with their hosts. This will open the door to validate methods of improving viral growth, morphogenesis and development, as well as to control strategies against unwanted microorganisms. The key feature of VIROINF is its interdisciplinary nature, which brings together virologists and bioinformaticians to achieve common goals.

scholarly journals The growing repertoire of genetic tools for dissecting chlamydial pathogenesis

2021 ◽  
Author(s):  
Arkaprabha Banerjee ◽  
David E Nelson
Keyword(s):  
Genetic Engineering ◽  
Intracellular Bacteria ◽  
Human Pathogens ◽  
Pathogenic Potential ◽  
Host Preferences ◽  
Genetic Tools ◽  
Obligate Intracellular ◽  
Obligate Intracellular Bacteria ◽  
Multiple Species

Abstract Multiple species of obligate intracellular bacteria in the genus Chlamydia are important veterinary and/or human pathogens. These pathogens all share similar biphasic developmental cycles and transition between intracellular vegetative reticulate bodies and infectious elementary forms, but vary substantially in their host preferences and pathogenic potential. A lack of tools for genetic engineering of these organisms has long been an impediment to the study of their biology and pathogenesis. However, the refinement of approaches developed in C. trachomatis over the last ten years, and adaptation of some of these approaches to other Chlamydia spp. in just the last few years, has opened exciting new possibilities for studying this ubiquitous group of important pathogens.

scholarly journals MetR-Regulated Vibrio cholerae Metabolism Is Required for Virulence

mBio ◽  
2012 ◽  
Vol 3 (5) ◽  
Author(s):  
Ryan W. Bogard ◽  
Bryan W. Davies ◽  
John J. Mekalanos
Keyword(s):  
Amino Acid ◽  
Vibrio Cholerae ◽  
Virulence Factor ◽  
Current Knowledge ◽  
Intestinal Colonization ◽  
Wild Type ◽  
Pathogenic Potential ◽  
Content Type ◽  
Mouse Intestine

ABSTRACTLysR-type transcriptional regulators (LTTRs) are the largest, most diverse family of prokaryotic transcription factors, with regulatory roles spanning metabolism, cell growth and division, and pathogenesis. Using a sequence-defined transposon mutant library, we screened a panel ofV. choleraeEl Tor mutants to identify LTTRs required for host intestinal colonization. Surprisingly, out of 38 LTTRs, only one severely affected intestinal colonization in the suckling mouse model of cholera: the methionine metabolism regulator, MetR. Genetic analysis of genes influenced by MetR revealed thatglyA1andmetJwere also required for intestinal colonization. Chromatin immunoprecipitation of MetR and quantitative reverse transcription-PCR (qRT-PCR) confirmed interaction with and regulation ofglyA1, indicating that misregulation ofglyA1is likely responsible for the colonization defect observed in themetRmutant. TheglyA1mutant was auxotrophic for glycine but exhibited wild-type trimethoprim sensitivity, making folate deficiency an unlikely cause of its colonization defect. MetJ regulatory mutants are not auxotrophic but are likely altered in the regulation of amino acid-biosynthetic pathways, including those for methionine, glycine, and serine, and this misregulation likely explains its colonization defect. However, mutants defective in methionine, serine, and cysteine biosynthesis exhibited wild-type virulence, suggesting that these amino acids can be scavenged in vivo. Taken together, our results suggest that glycine biosynthesis may be required to alleviate an in vivo nutritional restriction in the mouse intestine; however, additional roles for glycine may exist. Irrespective of the precise nature of this requirement, this study illustrates the importance of pathogen metabolism, and the regulation thereof, as a virulence factor.IMPORTANCEVibrio choleraecontinues to be a severe cause of morbidity and mortality in developing countries. Identification ofV. choleraefactors critical to disease progression offers the potential to develop or improve upon therapeutics and prevention strategies. To increase the efficiency of virulence factor discovery, we employed a regulator-centric approach to multiplex our in vivo screening capabilities and allow whole regulons inV. choleraeto be interrogated for pathogenic potential. We identified MetR as a new virulence regulator and serine hydroxymethyltransferase GlyA1 as a new MetR-regulated virulence factor, both required byV. choleraeto colonize the infant mouse intestine. Bacterial metabolism is a prerequisite to virulence, and current knowledge of in vivo metabolism of pathogens is limited. Here, we expand the known role of amino acid metabolism and regulation in virulence and offer new insights into the in vivo metabolic requirements ofV. choleraewithin the mouse intestine.

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