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The American Journal of Tropical... Aug 2019is a member of the family Enterobacteriaceae that has been commonly implicated as a causative agent of diarrheal infection in humans and animals. Recent outbreaks of... (Review)
Review
is a member of the family Enterobacteriaceae that has been commonly implicated as a causative agent of diarrheal infection in humans and animals. Recent outbreaks of in both developing and developed countries have raised public health concerns. Several studies have suggested that can cause diarrhea by invading the intestinal mucosa, although its pathogenicity has not been well established. Often routine laboratory investigations that seek etiological agents of diarrhea do not actively pursue detection. Therefore, routine laboratory diagnosis should be given more attention for better understanding the epidemiology and pathogenicity of .
Topics: Animals; Diarrhea; Disease Outbreaks; Enterobacteriaceae Infections; Feces; Foodborne Diseases; Providencia
PubMed: 31218997
DOI: 10.4269/ajtmh.18-0376 -
PLoS Pathogens Sep 2022Bacteria from the genus Providencia are ubiquitous Gram-negative opportunistic pathogens, causing "travelers' diarrhea", urinary tract, and other nosocomial infections...
Lipopolysaccharide -mediated resistance to host antimicrobial peptides and hemocyte-derived reactive-oxygen species are the major Providencia alcalifaciens virulence factors in Drosophila melanogaster.
Bacteria from the genus Providencia are ubiquitous Gram-negative opportunistic pathogens, causing "travelers' diarrhea", urinary tract, and other nosocomial infections in humans. Some Providencia strains have also been isolated as natural pathogens of Drosophila melanogaster. Despite clinical relevance and extensive use in Drosophila immunity research, little is known about Providencia virulence mechanisms and the corresponding insect host defenses. To close this knowledge gap, we investigated the virulence factors of a representative Providencia species-P. alcalifaciens which is highly virulent to fruit flies and amenable to genetic manipulations. We generated a P. alcalifaciens transposon mutant library and performed an unbiased forward genetics screen in vivo for attenuated mutants. Our screen uncovered 23 mutants with reduced virulence. The vast majority of them had disrupted genes linked to lipopolysaccharide (LPS) synthesis or modifications. These LPS mutants were sensitive to cationic antimicrobial peptides (AMPs) in vitro and their virulence was restored in Drosophila mutants lacking most AMPs. Thus, LPS-mediated resistance to host AMPs is one of the virulence strategies of P. alcalifaciens. Another subset of P. alcalifaciens attenuated mutants exhibited increased susceptibility to reactive oxygen species (ROS) in vitro and their virulence was rescued by chemical scavenging of ROS in flies prior to infection. Using genetic analysis, we found that the enzyme Duox specifically in hemocytes is the source of bactericidal ROS targeting P. alcalifaciens. Consistently, the virulence of ROS-sensitive P. alcalifaciens mutants was rescued in flies with Duox knockdown in hemocytes. Therefore, these genes function as virulence factors by helping bacteria to counteract the ROS immune response. Our reciprocal analysis of host-pathogen interactions between D. melanogaster and P. alcalifaciens identified that AMPs and hemocyte-derived ROS are the major defense mechanisms against P. alcalifaciens, while the ability of the pathogen to resist these host immune responses is its major virulence mechanism. Thus, our work revealed a host-pathogen conflict mediated by ROS and AMPs.
Topics: Animals; Antimicrobial Peptides; Drosophila melanogaster; Hemocytes; Humans; Lipopolysaccharides; Oxygen; Providencia; Reactive Oxygen Species; Virulence Factors
PubMed: 36084158
DOI: 10.1371/journal.ppat.1010825 -
Microbiology Resource Announcements Feb 2022Eight Providencia alcalifaciens isolates from eight different dogs in Norway with acute hemorrhagic diarrhea were sequenced. Based on Illumina and Oxford Nanopore...
Eight Providencia alcalifaciens isolates from eight different dogs in Norway with acute hemorrhagic diarrhea were sequenced. Based on Illumina and Oxford Nanopore Technologies sequencing, all of the genomes were complete and closed after hybrid assembly.
PubMed: 35175129
DOI: 10.1128/mra.00955-21 -
Biology Feb 2023Parasitoids are promising biocontrol agents of the devastating fruit fly, . However, parasitoid performance is a function of several factors, including host-associated...
Parasitoids are promising biocontrol agents of the devastating fruit fly, . However, parasitoid performance is a function of several factors, including host-associated symbiotic bacteria. , , and are among the symbiotic bacteria commonly associated with , and they influence the eco-physiological functioning of this pest. However, whether these bacteria influence the interaction between this pest and its parasitoids is unknown. This study sought to elucidate the nature of the interaction of the parasitoids, , , and with as mediated by symbiotic bacteria. Three types of fly lines were used: axenic, symbiotic, and bacteria-mono-associated (, , and ). The suitable stages of each fly line were exposed to the respective parasitoid species and reared until the emergence of adult flies/parasitoids. Thereafter, data on the emergence and parasitoid fitness traits were recorded. No wasps emerged from the fly lines exposed to . The highest emergence of . and was recorded in the fly lines. The parasitoid progeny from the and fly lines had the longest developmental time and the largest body size. Conversely, parasitoid fecundity was significantly lower in the lines, whereas the lines significantly improved fecundity. These results elucidate some effects of bacterial symbionts on host-parasitoid interactions and their potential in enhancing parasitoid-oriented management strategies against .
PubMed: 36829551
DOI: 10.3390/biology12020274 -
Journal of Veterinary Internal Medicine Sep 2021A severe form of acute hemorrhagic diarrhea syndrome (AHDS) occurred in dogs in the Oslo region of Norway during autumn 2019.
BACKGROUND
A severe form of acute hemorrhagic diarrhea syndrome (AHDS) occurred in dogs in the Oslo region of Norway during autumn 2019.
OBJECTIVES
To characterize the fecal microbiota of dogs with AHDS during the outbreak and compare it to that of healthy dogs from the same period and before the outbreak.
ANIMALS
Dogs with AHDS (n = 50), dogs with nonhemorrhagic diarrhea (n = 3), and healthy dogs (n = 11) were sampled during the outbreak. In addition, 78 healthy dogs from the same region were sampled before the outbreak between 2017 and 2018.
METHODS
Retrospective case-control study. The fecal microbiotas were characterized using 16S rRNA gene amplicon sequencing.
RESULTS
Dogs with AHDS had significantly different microbiota composition (R = .07, P < .001) and decreased intestinal diversity relative to healthy dogs from the outbreak period (median, 2.7; range, 0.9-3.5 vs median, 3.2; range, 2.6-4.0; P < .001). The microbiota in dogs with AHDS was characterized by a decrease of Firmicutes and an outgrowth of Proteobacteria, with increased numbers of Clostridium perfringens and Providencia spp. Among the Providencia spp., 1 showed 100% sequence identity with a Providencia alcalifaciens strain that was cultivated and isolated from the same outbreak. No Providencia spp. was found in healthy dogs sampled before the outbreak.
CONCLUSIONS AND CLINICAL IMPORTANCE
Dogs with AHDS had marked changes in fecal microbiota including increased numbers of Providencia spp. and C. perfringens, which may have contributed to the severity of this illness.
Topics: Animals; Case-Control Studies; Diarrhea; Disease Outbreaks; Dog Diseases; Dogs; Feces; Microbiota; Providencia; RNA, Ribosomal, 16S; Retrospective Studies
PubMed: 34288148
DOI: 10.1111/jvim.16201 -
Frontiers in Cellular and Infection... 2024Acute haemorrhagic diarrhoea syndrome (AHDS) in dogs is a condition of unknown aetiology. is suspected to play a role in the disease as it was commonly found in dogs...
INTRODUCTION
Acute haemorrhagic diarrhoea syndrome (AHDS) in dogs is a condition of unknown aetiology. is suspected to play a role in the disease as it was commonly found in dogs suffering from AHDS during a Norwegian outbreak in 2019. The role of this bacterium as a constituent of the canine gut microbiota is unknown, hence this study set out to investigate its occurrence in healthy dogs using metagenomics.
MATERIALS AND METHODS
To decrease the likelihood of false detection, we established a metagenomic threshold for by spiking culture-negative stool samples with a range of bacterial dilutions and analysing these by qPCR and shotgun metagenomics. The detection limit for was determined and used to establish a metagenomic threshold. The threshold was validated on naturally contaminated faecal samples with known cultivation status for . Finally, the metagenomic threshold was used to determine the occurrence of in shotgun metagenomic datasets from canine faecal samples (n=362) collected in the HUNT One Health project.
RESULTS
The metagenomic assay and qPCR had a detection limit of 1.1x10 CFU per faecal sample, which corresponded to a Cq value of 31.4 and 569 unique mer counts by shotgun metagenomics. Applying this metagenomic threshold to 362 faecal metagenomic datasets from healthy dogs, was found in only 1.1% (95% CI [0.0, 6.8]) of the samples, and then in low relative abundances (median: 0.04%; range: 0.00 to 0.81%). The sensitivity of the qPCR and shotgun metagenomics assay was low, as only 40% of culture-positive samples were also positive by qPCR and metagenomics.
DISCUSSION
Using our detection limit, the occurrence of in faecal samples from healthy dogs was low. Given the low sensitivity of the metagenomic assay, these results do not rule out a significantly higher occurrence of this bacterium at a lower abundance.
Topics: Dogs; Animals; Diarrhea; Feces; Metagenome; Providencia; Bacteria; Metagenomics
PubMed: 38481663
DOI: 10.3389/fcimb.2024.1305742 -
Journal of Insect Science (Online) May 2023Mexican fruit fly (Anastrepha ludens (Loew)) (Diptera: Tephritidae) represents a major threat to fruit production in the Western Hemisphere. Sterile insect technique is...
Mexican fruit fly (Anastrepha ludens (Loew)) (Diptera: Tephritidae) represents a major threat to fruit production in the Western Hemisphere. Sterile insect technique is used to suppress and eradicate wild populations. Success of this control method necessitates weekly production of hundreds of millions of flies, their sterilization by irradiation, and their aerial release. Diet needed to produce large fly numbers are conducive to the spread of bacteria. Pathogenic bacteria were isolated from 3 rearing facilities and from multiple sources: eggs, larvae, pupae and spent diet, and were found to include some isolates identified to the genus Providencia (Enterobacteriales: Morganellaceae). We identified 41 Providencia isolates and tested their pathogenicity to A. ludens. Based on 16s rRNA sequences, 3 groups were clustered into several species of Providencia with varying capacities to affect the Mexican fruit fly production. Isolates putatively identified as P. alcalifaciens/P. rustigianii were all pathogenic causing larval and pupal yield reduction of 46-64% and 37-57%, respectively. Among them, Providencia isolate 3006 was the most pathogenic reducing larval and pupae yield by 73 and 81%, respectively. Isolates identified as P. sneebia were not pathogenic. The final cluster, P. rettgeri/P. vermicola, were variable in pathogenicity with 3 isolates yielding like the control and the rest causing larval and pupal yield reduction of 26-53% and 23-51%, respectively. Isolates putatively identified as P. alcalifaciens/P. rustigianii were more virulent than P. rettgeri/P. vermicola. Accurate identification of species is needed to diagnose and monitor pathogenic versus nonpathogenic Providencia strains.
Topics: Animals; Tephritidae; Providencia; Virulence; RNA, Ribosomal, 16S; Ovum; Larva; Pupa
PubMed: 37220089
DOI: 10.1093/jisesa/iead024 -
Archives of Razi Institute Jun 2023Probiotics have been used for over a century to prevent and treat diseases. They can reduce the effects of gastroenteritis and are now used to treat acute diarrhea. This...
Probiotics have been used for over a century to prevent and treat diseases. They can reduce the effects of gastroenteritis and are now used to treat acute diarrhea. This study aimed to evaluate the co-aggregative effects of probiotics bacteria against diarrheal causative bacteria. For this purpose, 11 isolates of probiotic bacteria were used in the current study, including three , one , two , three , and two isolates. All isolates were tested for antibiotic susceptibility, autoaggregation ability, adhesion ability, antibacterial activity, acid tolerance, and bile salts tolerance. The results showed that most of them had the ability to autoaggregate after 4 h, with the highest percentage of 57.14% for . For the antibiotic susceptibility test, all the isolates showed resistance against trimethoprim/sulfamethoxazole, except one isolate. Moreover, all the isolates, except one, were susceptible to both vancomycin and tetracycline. All tested isolates had adhesion ability with different survival rates, which reached 34.57% for in acidic conditions. Besides, the highest survival rate was 85.17%, which belonged to , for bile salt tolerance. Probiotic isolates had an antibacterial effect against diarrhea-causative bacteria with an inhibition diameter of 17-49 mm for different spp. and spp. isolates. Furthermore, the co-aggregation ability of probiotic isolates against diarrhea-causative bacteria was studied, and results showed that probiotic isolates had a co-aggregative effect against diarrhea-causative bacteria, , , and , after 24 h of incubation. The highest co-aggregative effect of probiotics isolates belonged to and against with a co-aggregation percentage of 100%, while the lowest co-aggregation rate was 14.29% against . The findings revealed the probiotic properties and co-aggregative effects of probiotic bacteria against diarrhea-causative bacteria.
Topics: Animals; Escherichia coli; Lactobacillus; Anti-Bacterial Agents; Bile Acids and Salts; Diarrhea; Probiotics
PubMed: 38028859
DOI: 10.22092/ARI.2022.359870.2494 -
Animals : An Open Access Journal From... Nov 2021An outbreak investigation was initiated in September 2019, following a notification to the Norwegian Food Safety Authority (NFSA) of an unusually high number of dogs...
An outbreak investigation was initiated in September 2019, following a notification to the Norwegian Food Safety Authority (NFSA) of an unusually high number of dogs with acute haemorrhagic diarrhoea (AHD) in Oslo. Diagnostic testing by reporting veterinarians had not detected a cause. The official investigation sought to identify a possible common cause, the extent of the outbreak and prevent spread. Epidemiological data were collected through a survey to veterinarians and interviews with dog owners. Diagnostic investigations included necropsies and microbiological, parasitological and toxicological analysis of faecal samples and food. In total, 511 dogs with acute haemorrhagic diarrhoea were registered between 1 August and 1 October. Results indicated a common point source for affected dogs, but were inconclusive with regard to common exposures. A notable finding was that 134 of 325 faecal samples (41%) cultured positive for . Whole genome sequencing (WGS) of 75 isolates from 73 dogs revealed that strains from 51 dogs belonged to the same WGS clone. Findings point to as implicated in the outbreak, but investigations are needed to reveal the pathogenic potential of in dogs and its epidemiology.
PubMed: 34827932
DOI: 10.3390/ani11113201 -
Journal of Bacteriology Aug 2020Chlorogenic acid (CGA) is a phenolic compound with well-known antibacterial properties against pathogens. In this study, structural and biochemical characterization was...
Chlorogenic acid (CGA) is a phenolic compound with well-known antibacterial properties against pathogens. In this study, structural and biochemical characterization was used to show the inhibitory role of CGA against the enzyme of the shikimate pathway, a well-characterized drug target in several pathogens. Here, we report the crystal structures of dehydroquinate synthase (DHQS), the second enzyme of the shikimate pathway, from (DHQS), in binary complex with NAD and ternary complex with NAD and CGA. Structural analyses reveal that CGA occupies the substrate position in the active site of DHQS, which disables domain movements, leaving the enzyme in an open and catalysis-incompetent state. The binding analyses by isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR) show that CGA binds to DHQS with (equilibrium dissociation constant) values of 6.3 μM and 0.5 μM, respectively. nzyme inhibition studies show that CGA inhibits DHQS with a of 235 ± 21 μM, while it inhibits the growth of , , , and with MIC values of 60 to 100 μM. In the presence of aromatic amino acids supplied externally, CGA does not show the toxic effect. These results, along with the observations of the inhibition of the 3-deoxy-d-arabino-heptulosonate-7-phosphate (DAHP) regulatory domain by CGA in our previous study, suggest that CGA binds to shikimate pathway enzymes with high affinity and inhibits their catalysis and can be further exploited for designing novel drug-like molecules. The shikimate pathway is an attractive target for the development of herbicides and antimicrobial agents, as it is essential in plants, bacteria, and apicomplexan parasites but absent in humans. The enzymes of shikimate pathway are conserved among bacteria. Thus, the inhibitors of the shikimate pathway act on wide range of pathogens. We have identified that chlorogenic acid targets the enzymes of the shikimate pathway. The crystal structure of dehydroquinate synthase, the second enzyme of the pathway, in complex with chlorogenic acid and enzymatic inhibition studies explains the mechanism of inhibition of chlorogenic acid. These results suggest that chlorogenic acid has a good chemical scaffold and have important implications for its further development as a potent inhibitor of shikimate pathway enzymes.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Binding Sites; Catalytic Domain; Chlorogenic Acid; Kinetics; Phosphorus-Oxygen Lyases; Protein Binding; Providencia; Shikimic Acid
PubMed: 32661075
DOI: 10.1128/JB.00248-20