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International Journal of Environmental... Nov 2019Drinking water outbreaks occur worldwide and may be caused by several factors, including raw water contamination, treatment deficiencies, and distribution network...
Drinking water outbreaks occur worldwide and may be caused by several factors, including raw water contamination, treatment deficiencies, and distribution network failure. This study describes two drinking water outbreaks in Finland in 2016 (outbreak I) and 2018 (outbreak II). Both outbreaks caused approximately 450 illness cases and were due to drinking water pipe breakage and subsequent wastewater intrusion into the distribution system. In both outbreaks, the sapovirus was found in patient samples as the main causative agent. In addition, adenoviruses and (outbreak I), and noroviruses, astroviruses, enterotoxigenic and enterohemorragic (ETEC and EHEC, respectively) and (outbreak II) were detected in patient samples. Water samples were analyzed for the selected pathogens largely based on the results of patient samples. In addition, traditional fecal indicator bacteria and host-specific microbial source tracking (MST) markers (GenBac3 and HF183) were analyzed from water. In drinking water, sapovirus and enteropathogenic (EPEC) were found in outbreak II. The MST markers proved useful in the detection of contamination and to ensure the success of contaminant removal from the water distribution system. As mitigation actions, boil water advisory, alternative drinking water sources and chlorination were organized to restrict the outbreaks and to clean the contaminated distribution network. This study highlights the emerging role of sapoviruses as a waterborne pathogen and warrants the need for testing of multiple viruses during outbreak investigation.
Topics: Bacterial Infections; Disease Outbreaks; Drinking Water; Feces; Finland; Humans; Virus Diseases; Wastewater; Water Microbiology; Water Purification
PubMed: 31717479
DOI: 10.3390/ijerph16224376 -
BMC Veterinary Research Dec 2022Bacterial pathogens are a great threat to fish production. Gram-negative bacteria are among the major bacterial fish pathogens and are zoonotic with the potential to...
Isolation and identification of major bacteria from three Ethiopian rift valley lakes live and processed fish, and water samples: implications in sanitary system of fish products.
Bacterial pathogens are a great threat to fish production. Gram-negative bacteria are among the major bacterial fish pathogens and are zoonotic with the potential to infect humans. This cross-sectional study was conducted to isolate and identify major gram-negative bacteria from live and processed fish, and water samples from Lakes Hawassa, Langanoo and Ziway. A total of 674 different types of samples: 630 tissue samples (210 samples for each intestine, Kkidney and liver collected from 210 live fish (Oreochromis niloticus, Cyprinus carpio and Clarias gariepinus), 20 processed fish samples from lake Ziway fish processing center and 24 lake water samples were included in the study from each lake. The mean values of pH, temperature, dissolved oxygen and nitrate in all water samples were within the normal range at which most freshwater fish species become non-stressed. Of a total of 674 samples included in the study, bacteria were isolated from 154(22.8%) samples with significant difference (P < 0.05) observed in some isolates with respect to sample origin. Of these 154 isolates, 103(66.8%) isolates were gram-negative bacteria consisting of 15 species based on morphology and a range of biochemical tests. From live fish samples, Escherichia coli was the dominant species with 15 isolates followed by Edwardsiella tarda (12), Salmonella Paratyphi (10), Salmonella Typhi (9), Shigella dysenteriae (7), Shigella flexneri (7), Klebsiella pneumonia (7), Enterobacter aerogenes (6), Enterobacter cloacae (5), Pseudomonas aeruginosa (5), Vibrio parahemolyticus (5), Aeromonas sobria (4), Citrobacter freundii (4), Citrobacter koseri (4) and Plesiomonas shigelloides (3). The detection of the common fecal coliforms (E. coli, K. pneumoniae and E. aerogenes) and Salmonella spp. in processed fish indicates the potential danger of passage of pathogenic bacteria and/or their poisons to humans via infected and/or contaminated fish products. Human infection by pathogenic fish bacteria and food poisoning is possible through contamination of fish product in fish production chain due to inadequate handling, poor hygiene and contact with contaminated water. Therefore, producers, consumers and all other stakeholders need to be cautious during handling, processing and consumption of fish harvested from the study lakes.
Topics: Animals; Bacteria; Carps; Cross-Sectional Studies; Escherichia coli; Fish Products; Gram-Negative Bacteria; Lakes; Water; Ethiopia
PubMed: 36517783
DOI: 10.1186/s12917-022-03508-w -
BMC Microbiology Dec 2022RpoN, also known as σ, first reported in Escherichia coli, is a subunit of RNA polymerase that strictly controls the expression of different genes by identifying...
BACKGROUND
RpoN, also known as σ, first reported in Escherichia coli, is a subunit of RNA polymerase that strictly controls the expression of different genes by identifying specific promoter elements. RpoN has an important regulatory function in carbon and nitrogen metabolism and participates in the regulation of flagellar synthesis, bacterial motility and virulence. However, little is known about the effect of RpoN in Plesiomonas shigelloides.
RESULTS
To identify pathways controlled by RpoN, RNA sequencing (RNA-Seq) of the WT and the rpoN deletion strain was carried out for comparison. The RNA-seq results showed that RpoN regulates ~ 13.2% of the P. shigelloides transcriptome, involves amino acid transport and metabolism, glycerophospholipid metabolism, pantothenate and CoA biosynthesis, ribosome biosynthesis, flagellar assembly and bacterial secretion system. Furthermore, we verified the results of RNA-seq using quantitative real-time reverse transcription PCR, which indicated that the absence of rpoN caused downregulation of more than half of the polar and lateral flagella genes in P. shigelloides, and the ΔrpoN mutant was also non-motile and lacked flagella. In the present study, the ability of the ΔrpoN mutant to kill E. coli MG1655 was reduced by 54.6% compared with that of the WT, which was consistent with results in RNA-seq, which showed that the type II secretion system (T2SS-2) genes and the type VI secretion system (T6SS) genes were repressed. By contrast, the expression of type III secretion system genes was largely unchanged in the ΔrpoN mutant transcriptome and the ability of the ΔrpoN mutant to infect Caco-2 cells was also not significantly different compared with the WT.
CONCLUSIONS
We showed that RpoN is required for the motility and contributes to the killing ability of P. shigelloides and positively regulates the T6SS and T2SS-2 genes.
Topics: Humans; RNA Polymerase Sigma 54; Gene Expression Regulation, Bacterial; Plesiomonas; Bacterial Proteins; Escherichia coli; Caco-2 Cells
PubMed: 36510135
DOI: 10.1186/s12866-022-02722-8 -
Virulence Dec 2023spp. are the causative agent of shigellosis (or bacillary dysentery), a diarrhoeal disease characterized for the bacterial invasion of gut epithelial cells. Among the 4... (Review)
Review
spp. are the causative agent of shigellosis (or bacillary dysentery), a diarrhoeal disease characterized for the bacterial invasion of gut epithelial cells. Among the 4 species included in the genus, is principally responsible for the disease in the developing world while is the main causative agent in high-income countries. Remarkably, as more countries improve their socioeconomic conditions, we observe an increase in the relative prevalence of . To date, the reasons behind this change in aetiology depending on economic growth are not understood. has been widely used as a model to study the pathogenesis of the genus, but as more research data are collected, important discrepancies with have come to light. In comparison to can be differentiated in numerous aspects; it presents a characteristic O-antigen identical to that of one serogroup of the environmental bacterium , a group 4 capsule, antibacterial mechanisms to outcompete and displace gut commensal bacteria, and a poorer adaptation to an intracellular lifestyle. In addition, the World Health Organization (WHO) have recognized the significant threat posed by antibiotic-resistant strains of , demanding new approaches. This review gathers knowledge on what is known about within the context of other spp. and aims to open the door for future research on understanding the increasing spread of this pathogen.
Topics: Humans; Shigella sonnei; Virulence; Prevalence; Anti-Bacterial Agents; Cell Differentiation; Dysentery, Bacillary
PubMed: 37994877
DOI: 10.1080/21505594.2023.2280838 -
MSystems Sep 2020is an emerging pathogen that has been shown to be involved in gastrointestinal diseases and extraintestinal infections in humans. However, the taxonomic position,...
is an emerging pathogen that has been shown to be involved in gastrointestinal diseases and extraintestinal infections in humans. However, the taxonomic position, evolutionary dynamics, and pathogenesis of remain unclear. We reported the draft genome sequences of 12 strains representing different serogroups. We were able to determine a clear distinction between and other members of via core genome phylogeny, Neighbor-Net network, and average genome identity analysis. The pan-genome analysis of revealed extensive genetic diversity and presented large flexible gene repertoires, while the core genome phylogeny exhibited a low level of clonality. The discordance between the core genome phylogeny and the pan-genome phylogeny indicated that flexible accessory genomes account for an important proportion of the evolution of , which was subsequently characterized by determinations of hundreds of horizontally transferred genes (horizontal genes), massive gene expansions and contractions, and diverse mobile genetic elements (MGEs). The apparently high levels of horizontal gene transfer (HGT) in were conferred from bacteria with novel properties from other taxa (mainly and ), which caused the historical taxonomic confusion and shaped the virulence gene pools. Furthermore, genomes contain many macromolecular secretion system genes, virulence factor genes, and resistance genes, indicating its potential to cause intestinal and invasive infections. Collectively, our work provides insights into the phylogenetic position, evolutionary dynamic, and pathogenesis of at the genomic level, which could facilitate the observation and research of this important pathogen. The taxonomic position of has been the subject of debate for a long time, and until now, the evolutionary dynamics and pathogenesis of were unclear. In this study, pan-genome analysis indicated extensive genetic diversity and the presence of large and variable gene repertoires. Our results revealed that horizontal gene transfer was the focal driving force for the genetic diversity of the pan-genome and might have contributed to the emergence of novel properties. and were found to be the predominant donor taxa for horizontal genes, which might have caused the taxonomic confusion historically. Comparative genomic analysis revealed the potential of to cause intestinal and invasive diseases. Our results could advance the understanding of the evolution and pathogenesis of , particularly in elucidating the role of horizontal gene transfer and investigating virulence-related elements.
PubMed: 32934114
DOI: 10.1128/mSystems.00448-20 -
Japanese Journal of Infectious Diseases Jul 2022The genus Plesiomonas, represented by a single species, Plesiomonas shigelloides, is a gram-negative bacillus associated with gastrointestinal and extraintestinal...
The genus Plesiomonas, represented by a single species, Plesiomonas shigelloides, is a gram-negative bacillus associated with gastrointestinal and extraintestinal diseases in humans. In this study, 44 clinical isolates (gastrointestinal, n = 41; extraintestinal, n = 3) were genetically confirmed to be P. shigelloides using the hug gene. All 20 virulence genes were detected in the gastrointestinal isolates, ranging from 7.7% to 100%; however, only 12 genes were detected in the extra-gastrointestinal isolates, ranging from 33.3% to 100%. The phlA gene was significantly associated with the gastrointestinal isolates (P = 0.0216). The results of this study suggest that phlA may play a role in gastrointestinal infections. However, pilF, tolC, and fur were detected in both gastrointestinal and extraintestinal clinical isolates, and further investigations are warranted to elucidate their role in the pathogenesis of P. shigelloides.
Topics: Gram-Negative Bacterial Infections; Humans; Plesiomonas; Virulence
PubMed: 35095023
DOI: 10.7883/yoken.JJID.2021.477 -
Frontiers in Microbiology 2022Microorganisms play as fundamental contributors to maintain hosts' fitness, which can be shaped by external environment. Moreover, symbiotic microbiome also varied...
Microorganisms play as fundamental contributors to maintain hosts' fitness, which can be shaped by external environment. Moreover, symbiotic microbiome also varied within species (e.g., between sexes and developmental stages). However, we still need more studies to quantify whether the intraspecific variation patterns of symbiotic microbes can be modified with the change of environment. The Chinese giant salamander (CGS; ) is a Critically Endangered species. Despite quantitative captive bred individuals were released to rebuild wild populations, the effectiveness is limited. More importantly, no studies have revealed the adaptation of released CGSs to the complex field conditions. In the present study, we explored whether reintroduction can reshape the intraspecific variations of symbiotic microbiota in captive bred CGSs using high-throughput amplicon sequencing of the16S rRNA gene. We found no significant difference of symbiotic microbiome in captive bred males and females, but released males and females differed significantly in skin microbiome. Juveniles had higher diversity of microbial symbiont than adults in hatchery, but lower diversity in field. Moreover, dominant bacterial taxa differed between juveniles and adults in both hatchery and field. Importantly, this symbiotic microbiome variations within species can be modified (alpha and beta diversity, and community composition) when captive bred individuals were released to the field. Overall, we observed a lower alpha diversity and higher relative abundance of , , and in the bacterial community of captive bred individuals. Instead, higher alpha diversity of symbiotic microbiota and higher relative abundance of S24-7 and was detected in released individuals. These modifications may associate with the change of living environment, as well as the specific behavior within CGSs (e.g., movement patterns and foraging activities). Future studies can incorporate other approaches (e.g., blood physiology) to better evaluate the growth and health of reintroduced CGSs.
PubMed: 36532427
DOI: 10.3389/fmicb.2022.1062604 -
Infectious Diseases (London, England) Sep 2019
Topics: Adolescent; Adult; Aeromonas; Aged; Aged, 80 and over; Child; Child, Preschool; Drug Resistance, Multiple, Bacterial; Female; Gram-Negative Bacterial Infections; Humans; Hungary; Male; Middle Aged; Plesiomonas; Retrospective Studies; Tertiary Care Centers; Young Adult
PubMed: 31298069
DOI: 10.1080/23744235.2019.1640389 -
Tropical Diseases, Travel Medicine and... 2019Traveler's diarrhea (TD) is a common health problem among visitors from developed to developing countries. Although global and regional estimates of pathogen...
BACKGROUND
Traveler's diarrhea (TD) is a common health problem among visitors from developed to developing countries. Although global and regional estimates of pathogen distribution are available, the etiology of diarrhea among non-military travelers to Thailand is largely unknown.
METHODS
A prospective TD case-control study was conducted among adult travelers from developed countries at a prominent hospital in Bangkok, Thailand during 2001-2003. Stool samples were collected from acute TD cases and non-diarrheal controls and analyzed for bacterial, viral, and protozoan pathogens by microbiology, ELISA or PCR methods. Calculation of adjusted odd ratios for risk factors was performed by logistic regression using STATA statistical software.
RESULTS
Stool samples were collected and analyzed from 389 TD cases and 400 non-diarrhea controls. At least one pathogen was detected in 227 (58%) cases and 124 (31%) controls. (14%), (14%), (14%), and norovirus (12%) were the most frequently isolated pathogens among cases and significantly associated with diarrhea at = 0.006, < 0.001, < 0.001, < 0.001, respectively. (3%) and ETEC (8%), detected in lower prevalence, also showed significant association with TD at < 0.001 and = 0.002, respectively. Travelers from East Asian countries had an increased risk of infection (Crude odds ratio: 3.1, -value = 0.001); travelers from the United States, Canada, and Europe had an increased risk of infection (Crude odds ratio: 2.6, -value = 0.001); and travelers from Australia and New Zealand had an increased risk of infection (Crude odds ratio: 3.2, -value = 0.009).
CONCLUSIONS
Etiology of TD in Thailand is mainly of bacterial origin. and norovirus are underappreciated diarrheagenic pathogens. In our study, the origin of the traveler plays an important role in diarrhea etiology. Understanding variations in TD severity and etiology among travelers from different regions warrants further study.
PubMed: 31183159
DOI: 10.1186/s40794-019-0085-9 -
Genome Biology and Evolution Feb 2022About 10% of bacteria have a multichromosome genome with a primary replicon of bacterial origin, called the chromosome, and other replicons of plasmid origin, the...
About 10% of bacteria have a multichromosome genome with a primary replicon of bacterial origin, called the chromosome, and other replicons of plasmid origin, the chromids. Studies on multichromosome bacteria revealed potential points of coordination between the replication/segregation of chromids and the progression of the cell cycle. For example, replication of the chromid of Vibrionales (called Chr2) is initiated upon duplication of a sequence carried by the primary chromosome (called Chr1), in such a way that replication of both replicons is completed synchronously. Also, Chr2 uses the Chr1 as a scaffold for its partition in the daughter cells. How many of the features detected so far are required for the proper integration of a secondary chromosome in the cell cycle? How many more features remain to be discovered? We hypothesized that critical features for the integration of the replication/segregation of a given chromid within the cell cycle program would be conserved independently of the species in which the chromid has settled. Hence, we searched for a chromid related to that found in Vibrionales outside of this order. We identified one in Plesiomonas shigelloides, an aquatic and pathogenic enterobacterium that diverged early within the clade of Enterobacterales. Our results suggest that the chromids present in P. shigelloides and Vibrionales derive from a common ancestor. We initiated in silico genomic and proteomic comparative analyses of P. shigelloides, Vibrionales, and Enterobacterales that enabled us to establish a list of features likely involved in the maintenance of the chromid within the host cell cycle.
Topics: Chromosomes, Bacterial; Genome, Bacterial; Plesiomonas; Proteomics; Vibrio
PubMed: 35078241
DOI: 10.1093/gbe/evac011