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Frontiers in Microbiology 2015The bacterial proteins of the Dsb family-important components of the post-translational protein modification system-catalyze the formation of disulfide bridges, a... (Review)
Review
The bacterial proteins of the Dsb family-important components of the post-translational protein modification system-catalyze the formation of disulfide bridges, a process that is crucial for protein structure stabilization and activity. Dsb systems play an essential role in the assembly of many virulence factors. Recent rapid advances in global analysis of bacteria have thrown light on the enormous diversity among bacterial Dsb systems. While the Escherichia coli disulfide bond-forming system is quite well understood, the mechanisms of action of Dsb systems in other bacteria, including members of class Epsilonproteobacteria that contain pathogenic and non-pathogenic bacteria colonizing extremely diverse ecological niches, are poorly characterized. Here we present a review of current knowledge on Epsilonproteobacteria Dsb systems. We have focused on the Dsb systems of Campylobacter spp. and Helicobacter spp. because our knowledge about Dsb proteins of Wolinella and Arcobacter spp. is still scarce and comes mainly from bioinformatic studies. Helicobacter pylori is a common human pathogen that colonizes the gastric epithelium of humans with severe consequences. Campylobacter spp. is a leading cause of zoonotic enteric bacterial infections in most developed and developing nations. We focus on various aspects of the diversity of the Dsb systems and their influence on pathogenicity, particularly because Dsb proteins are considered as potential targets for a new class of anti-virulence drugs to treat human infections by Campylobacter or Helicobacter spp.
PubMed: 26106374
DOI: 10.3389/fmicb.2015.00570 -
Journal of Applied Microbiology Jan 2016The pathogenic potential of Arcobacter butzleri isolates on human (HT-29/B6) and porcine epithelial (IPEC-J2) cells was investigated by in vitro assays.
AIMS
The pathogenic potential of Arcobacter butzleri isolates on human (HT-29/B6) and porcine epithelial (IPEC-J2) cells was investigated by in vitro assays.
METHODS AND RESULTS
Five of six A. butzleri isolates were able to adhere and invade HT-29/B6 cells while only four isolates adhered and two invaded IPEC-J2 cells. Two non- or poorly invasive A. butzleri isolates were highly cytotoxic to differentiated HT-29/B6 cells but none to IPEC-J2 cells as determined by WST-assays. Epithelial integrity of cell monolayers, monitored by measurement of the transepithelial electrical resistance (TER), was decreased by all A. butzleri isolates in HT-29/B6 and IPEC-J2 cells to 30-15% and 90-50% respectively.
CONCLUSION
The A. butzleri strain-specific pathomechanisms observed with the human colon cell line HT-29/B6, like adhesion, invasion and cytotoxicity might all contribute to epithelial barrier dysfunction, which could explain a leak-flux type of diarrhoea in humans. In contrast, porcine cells seem to be less susceptible to A. butzleri.
SIGNIFICANCE AND IMPACT OF THE STUDY
Arcobacter butzleri has enteric pathogenic potential, characterized by defined interactions with human epithelial cells and strain-specific pathomechanisms.
Topics: Animals; Arcobacter; Diarrhea; Epithelial Cells; Gram-Negative Bacterial Infections; HT29 Cells; Humans; Intestines; Swine; Swine Diseases; Virulence
PubMed: 26481610
DOI: 10.1111/jam.12979 -
Journal of Applied Microbiology Jan 2016The present study aimed to determine, by multilocus sequence type (MLST), the heterogeneity level of Arcobacter butzleri isolates and to compare MLST and pulsed-field... (Comparative Study)
Comparative Study
AIMS
The present study aimed to determine, by multilocus sequence type (MLST), the heterogeneity level of Arcobacter butzleri isolates and to compare MLST and pulsed-field gel electrophoresis (PFGE) in terms of discriminatory power (DI) as well as unidirectional and bi-directional concordance.
METHODS AND RESULTS
Arcobacter butzleri isolates (N = 133) from dairy products and environmental samples, collected from dairy plants, were characterized by MLST and PFGE with SacII and classified in 29 sequence types (STs), 47 PFGE and 62 type strains (TS). Among the 119 alleles, 19 were previously unreported and the same for all the STs but two. A significant linkage disequilibrium was detected when the complete ST data set was analysed The DIs of MLST, PFGE and their combination were 0·937, 0·953 and 0·965 respectively. The adjusted Wallace coefficients between MLST and PFGE as well as PFGE and MLST were 0·535 and 0·720 respectively; the adjusted Rand coefficient was 0·612.
CONCLUSIONS
The A. butzleri studied population showed recombination to some degree. PFGE showed a DI higher than MLST. Both methods presented good concordance. The TS analysis seems to show persistence of the same strain on time and possible cross-contaminations between food and environmental sites.
SIGNIFICANCE AND IMPACT OF THE STUDY
This study provides insights in the A. butzleri population found in raw milk, cheese, and dairy production plants. The data suggest that MLST and PFGE genotypes correlate reasonably well, although their combination results in optimal resolution.
Topics: Alleles; Arcobacter; Bacterial Typing Techniques; Dairy Products; Electrophoresis, Gel, Pulsed-Field; Food Handling; Genotype; Multilocus Sequence Typing
PubMed: 26481316
DOI: 10.1111/jam.12977 -
Frontiers in Microbiology 2023was recognized as an emerging enteropathogen and controversies regarding its classification persisted. This study aimed to reevaluate the taxonomy of utilizing the 16S...
was recognized as an emerging enteropathogen and controversies regarding its classification persisted. This study aimed to reevaluate the taxonomy of utilizing the 16S rRNA gene, 23S rRNA gene, single-copy orthologous genes, as well as genomic indices such as Average Nucleotide Identity (ANI) and DNA-DNA hybridization (). The taxonomy of this genus was reevaluated in this study using multiple indices with a dataset of 371 genomes comprising 34 known species and 14 potentially new species. Good discrimination could be achieved only in some species but not for the species with higher sequence similarity using the comparisons of the 16S rRNA gene and 23S rRNA gene sequences. A high-accuracy phylogenomic approach for was established using 84 single-copy orthologous genes obtained through various bioinformatics methods. One marker gene (gene711), which was found to possess the same distinguishing ability as ANI, and single-copy orthologous methods, was identified as a reliable locus for inferring the phylogeny of the genus. The effective species classification was achieved by employing gene711 with a sequence similarity exceeding 96%, even for species like , , and , which exhibited ambiguous classification using ANI and . Additionally, excellent subspecies categorizing among could be distinguished using gene711. In conclusion, this framework strategy had the potential advantage of developing rapid species identification, particularly for highly variable species, providing a novel insight into the behavior and characteristics of .
PubMed: 37881248
DOI: 10.3389/fmicb.2023.1278268 -
European Journal of Microbiology &... Mar 2016We have previously shown that Arcobacter butzleri induces intestinal, extra-intestinal, and systemic immune responses in perorally infected gnotobiotic IL-10(-/-) mice...
We have previously shown that Arcobacter butzleri induces intestinal, extra-intestinal, and systemic immune responses in perorally infected gnotobiotic IL-10(-/-) mice in a strain-dependent fashion. Here, we present a comprehensive survey of small and large intestinal expression profiles of inflammatory and regulatory mediators as well as of the matrix-degrading gelatinases MMP-2 and MMP-9 following murine A. butzleri infection. Gnotobiotic IL-10(-/-) mice were infected with A. butzleri strains CCUG 30485 or C1 of human and chicken origin, respectively. At day 6 following A. butzleri infection, mucin-2 mRNA, an integral part of the intestinal mucus layer, was downregulated in the colon, whereas TNF and IL-23p19 mRNA were upregulated in the ileum. Furthermore, IFN-γ, IL-17A, IL-1β, and IL-22 mRNA were upregulated in both colonic and ileal ex vivo biopsies at day 6 post strain CCUG 30485 infection. These changes were accompanied by downregulated colonic MMP-9 levels, whereas both MMP-2 and MMP-9 mRNA were upregulated in the ileum. In conclusion, these data indicate that A. butzleri infection induces changes in the expression of genes involved in pro-inflammatory and regulatory immune responses as well as in tissue degradation.
PubMed: 27141315
DOI: 10.1556/1886.2016.00005 -
Le Infezioni in Medicina 2024(formerly ), is a newly recognized like emerging foodborne pathogen worldwide, usually causing gastrointestinal symptoms in young children. A 4-year-old boy was...
(formerly ), is a newly recognized like emerging foodborne pathogen worldwide, usually causing gastrointestinal symptoms in young children. A 4-year-old boy was admitted to the Department of Pediatrics, University Hospital of Split, Croatia, because of malnutrition, lost appetite and prolonged watery diarrhea. A comprehensive diagnostics, including biochemistry, haematology, allergology, microbiology and radiology, were performed. The only positive microbiology result was unexpected isolation of on selective media for , after 48 hours of incubation on 42°C, among microaerophilic atmosphere. Clinical course was favorable and after symptomatic therapy child was discharged in good clinical condition and normal peristalsis to home care, with the recommendation of taking high-protein preparations to improve nutritional status. In addition, we performed a literature review of clinical cases caused by infection. The first report of isolated from stool sample in a 4-year old boy in Croatia, along with other clinical reports in literature, highlights the importance of standardisation and improvement of microbiological analysis, especially implementation of new methods for the identification of emerging pathogens.
PubMed: 38827827
DOI: 10.53854/liim-3202-12 -
Journal of Environmental Management Jan 2022Woodchip bioreactors are being successfully applied to remove nitrate from commercial land-based recirculating aquaculture system (RAS) effluents. In order to understand...
Woodchip bioreactors are being successfully applied to remove nitrate from commercial land-based recirculating aquaculture system (RAS) effluents. In order to understand and optimize the overall function of these bioreactors, knowledge on the microbial communities, especially on the microbes with potential for production or mitigation of harmful substances (e.g. hydrogen sulfide; HS) is needed. In this study, we quantified and characterized bacterial and fungal communities, including potential HS producers and consumers, using qPCR and high throughput sequencing of 16S rRNA gene. We took water samples from bioreactors and their inlet and outlet, and sampled biofilms growing on woodchips and on the outlet of the three full-scale woodchip bioreactors treating effluents of three individual RAS. We found that bioreactors hosted a high biomass of both bacteria and fungi. Although the composition of microbial communities of the inlet varied between the bioreactors, the conditions in the bioreactors selected for the same core microbial taxa. The HS producing sulfate reducing bacteria (SRB) were mainly found in the nitrate-limited outlets of the bioreactors, the main groups being deltaproteobacterial Desulfobulbus and Desulfovibrio. The abundance of HS consuming sulfate oxidizing bacteria (SOB) was 5-10 times higher than that of SRB, and SOB communities were dominated by Arcobacter and other genera from phylum Epsilonbacteraeota, which are also capable of autotrophic denitrification. Indeed, the relative abundance of potential autotrophic denitrifiers of all denitrifier sequences was even 54% in outlet water samples and 56% in the outlet biofilm samples. Altogether, our results show that the highly abundant bacterial and fungal communities in woodchip bioreactors are shaped through the conditions prevailing within the bioreactor, indicating that the bioreactors with similar design and operational settings should provide similar function even when conditions in the preceding RAS would differ. Furthermore, autotrophic denitrifiers can have a significant role in woodchip biofilters, consuming potentially produced HS and removing nitrate, lengthening the operational age and thus further improving the overall environmental benefit of these bioreactors.
Topics: Aquaculture; Bioreactors; Denitrification; Microbiota; Nitrates; RNA, Ribosomal, 16S
PubMed: 34592671
DOI: 10.1016/j.jenvman.2021.113852 -
Journal of Food Protection Dec 2002Arcobacter butzleri is a pathogenic bacterium that has been found in dairy cattle, pigs, poultry, and humans. As of this writing, there are no data on the incidence of... (Comparative Study)
Comparative Study
Arcobacter butzleri is a pathogenic bacterium that has been found in dairy cattle, pigs, poultry, and humans. As of this writing, there are no data on the incidence of A. butzleri in beef cattle. Given the differences in rearing practices used for feedlot cattle and those used for dairy cattle, differences in the incidences of this organism in various types of cattle may also exist. Numerous culture methods have been used to isolate A. butzleri, but there are few data on the comparative efficacies of these methods. The objectives of this study were to determine the incidence of A. butzleri in cattle from Texas and to compare the effectiveness levels of the Johnson-Murano (JM) method (consisting of enrichment in JM broth followed by plating on JM agar) and the Collins method (consisting of enrichment in EMJH-P80 broth followed by plating on Cephalothin, Vancomycin, and Amphotericin B [CVA] agar) in the isolation of this organism. Fifty cattle each from two feedlots, a dairy, and a stocker yard were sampled. Fecal swabs were obtained from cattle, and each sample was cultured by the JM method, the Collins method, and combinations of the two methods with the broth of one method being used with the agar of the other. Polymerase chain reaction was used to identify the isolates for confirmation of A. butzleri. Samples from 18 of 200 cattle tested positive for A. butzleri. This organism was detected by the JM method in 4.5% of the samples and by the Collins method in 2.5% of the samples. An incidence of 4.0% was found when JM broth was used with CVA agar, while no samples tested positive for A. butzleri when EMJH-P80 broth was used with JM agar.
Topics: Agar; Animals; Arcobacter; Cattle; Colony Count, Microbial; Culture Media; Feces; Female; Food Contamination; Food Microbiology; Incidence; Male; Polymerase Chain Reaction; Sensitivity and Specificity; Texas
PubMed: 12495000
DOI: 10.4315/0362-028x-65.12.1849 -
Applied and Environmental Microbiology Oct 2020Rapid and accurate identification of is of great importance because it is considered an emerging food- and waterborne pathogen and potential zoonotic agent. Raman...
Rapid and accurate identification of is of great importance because it is considered an emerging food- and waterborne pathogen and potential zoonotic agent. Raman spectroscopy can differentiate bacteria based on Raman scattering spectral patterns of whole cells in a fast, reagentless, and easy-to-use manner. We aimed to detect and discriminate bacteria at the species level using confocal micro-Raman spectroscopy (785 nm) coupled with neural networks. A total of 82 reference and field isolates of 18 species from clinical, environmental, and agri-food sources were included. We determined that the bacterial cultivation time and growth temperature did not significantly influence the Raman spectral reproducibility and discrimination capability. The genus could be successfully differentiated from the closely related genera and using principal-component analysis. For the identification of to the species level, an accuracy of 97.2% was achieved for all 18 species using Raman spectroscopy combined with a convolutional neural network (CNN). The predictive capability of Raman-CNN was further validated using an independent data set of 12 strains. Furthermore, a Raman spectroscopy-based fully connected artificial neural network (ANN) was constructed to determine the actual ratio of a specific species in a bacterial mixture ranging from 5% to 100% by biomass (regression coefficient >0.99). The application of both CNN and fully connected ANN improved the accuracy of Raman spectroscopy for bacterial species determination compared to the conventional chemometrics. This newly developed approach enables rapid identification and species determination of within an hour following cultivation. Rapid identification of bacterial pathogens is critical for developing an early warning system and performing epidemiological investigation. is an emerging foodborne pathogen and has become more important in recent decades. The incidence of species in the agro-ecosystem is probably underestimated mainly due to the limitation in the available detection and characterization techniques. Raman spectroscopy combined with machine learning can accurately identify at the species level in a rapid and reliable manner, providing a promising tool for epidemiological surveillance of this microbe in the agri-food chain. The knowledge elicited from this study has the potential to be used for routine bacterial screening and diagnostics by the government, food industry, and clinics.
Topics: Arcobacter; Bacteriological Techniques; Neural Networks, Computer; Spectrum Analysis, Raman
PubMed: 32801186
DOI: 10.1128/AEM.00924-20 -
Microorganisms Apr 2024In contrast to "frank" pathogens, like , , and , that always have a probability of disease, "opportunistic" pathogens are organisms that cause an infectious disease in a... (Review)
Review
In contrast to "frank" pathogens, like , , and , that always have a probability of disease, "opportunistic" pathogens are organisms that cause an infectious disease in a host with a weakened immune system and rarely in a healthy host. Historically, drinking water treatment has focused on control of frank pathogens, particularly those from human or animal sources (like , , or ), but in recent years outbreaks from drinking water have increasingly been due to opportunistic pathogens. Characteristics of opportunistic pathogens that make them problematic for water treatment include: (1) they are normally present in aquatic environments, (2) they grow in biofilms that protect the bacteria from disinfectants, and (3) under appropriate conditions in drinking water systems (e.g., warm water, stagnation, low disinfectant levels, etc.), these bacteria can amplify to levels that can pose a public health risk. The three most common opportunistic pathogens in drinking water systems are , , and . This report focuses on these organisms to provide information on their public health risk, occurrence in drinking water systems, susceptibility to various disinfectants, and other operational practices (like flushing and cleaning of pipes and storage tanks). In addition, information is provided on a group of nine other opportunistic pathogens that are less commonly found in drinking water systems, including , , , , , , , and several free-living amoebae including and species of The public health risk for these microbes in drinking water is still unclear, but in most cases, efforts to manage , mycobacteria, and risks will also be effective for these other opportunistic pathogens. The approach to managing opportunistic pathogens in drinking water supplies focuses on controlling the growth of these organisms. Many of these microbes are normal inhabitants in biofilms in water, so the attention is less on eliminating these organisms from entering the system and more on managing their occurrence and concentrations in the pipe network. With anticipated warming trends associated with climate change, the factors that drive the growth of opportunistic pathogens in drinking water systems will likely increase. It is important, therefore, to evaluate treatment barriers and management activities for control of opportunistic pathogen risks. Controls for primary treatment, particularly for turbidity management and disinfection, should be reviewed to ensure adequacy for opportunistic pathogen control. However, the major focus for the utility's opportunistic pathogen risk reduction plan is the management of biological activity and biofilms in the distribution system. Factors that influence the growth of microbes (primarily in biofilms) in the distribution system include, temperature, disinfectant type and concentration, nutrient levels (measured as AOC or BDOC), stagnation, flushing of pipes and cleaning of storage tank sediments, and corrosion control. Pressure management and distribution system integrity are also important to the microbial quality of water but are related more to the intrusion of contaminants into the distribution system rather than directly related to microbial growth. Summarizing the identified risk from drinking water, the availability and quality of disinfection data for treatment, and guidelines or standards for control showed that adequate information is best available for management of . For , the risk for this organism has been clearly established from drinking water, cases have increased worldwide, and it is one of the most identified causes of drinking water outbreaks. Water management best practices (e.g., maintenance of a disinfectant residual throughout the distribution system, flushing and cleaning of sediments in pipelines and storage tanks, among others) have been shown to be effective for control of in water supplies. In addition, there are well documented management guidelines available for the control of the organism in drinking water distribution systems. By comparison, management of risks for from water are less clear than for . Treatment of is difficult due to its resistance to disinfection, the tendency to form clumps, and attachment to surfaces in biofilms. Additionally, there are no guidelines for management of in drinking water, and one risk assessment study suggested a low risk of infection. The role of tap water in the transmission of the other opportunistic pathogens is less clear and, in many cases, actions to manage (e.g., maintenance of a disinfectant residual, flushing, cleaning of storage tanks, etc.) will also be beneficial in helping to manage these organisms as well.
PubMed: 38792751
DOI: 10.3390/microorganisms12050916