scholarly journals Increased Persistence of Salmonella enterica Serovar Typhi in the Presence of Acanthamoeba castellanii

2011 ◽  
Vol 77 (21) ◽  
pp. 7640-7646 ◽  
Author(s):  
Frédéric Douesnard-Malo ◽  
France Daigle
Keyword(s):  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Systemic Disease ◽  
Acanthamoeba Castellanii ◽  
Selective Advantage ◽  
Viable Count ◽  
Physical Contact ◽  
Content Type ◽  
Contaminated Food ◽  
Cultured Bacteria

ABSTRACTSalmonella entericaserovar Typhi (S. Typhi) is the etiological agent of the systemic disease typhoid fever. Transmission occurs via ingestion of contaminated food or water.S. Typhi is specific to humans, and no animal or environmental reservoirs are known. As the free-living amoebaAcanthamoeba castellaniiis an environmental host for many pathogenic bacteria, this study investigates interactions betweenS. Typhi andA. castellaniiby using cocultures. Growth of both organisms was estimated by cell count, viable count, flow cytometry, and fluorescence microscopy. Results indicate thatS. Typhi can survive at least 3 weeks when grown withA. castellanii, as opposed to less than 10 days when grown as singly cultured bacteria under the same conditions. Interestingly, growth rates of amoebae after 14 days were similar in cocultures or when amoebae were singly cultured, suggesting thatS. Typhi is not cytotoxic toA. castellanii. Bacteria surviving in coculture were not intracellular and did not require a physical contact with amoebae for their survival. These results suggest thatS. Typhi may have a selective advantage when it is associated withA. castellaniiand that amoebae may contribute toS. Typhi persistence in the environment.

scholarly journals Specific Discrimination of Three Pathogenic Salmonella enterica subsp. enterica Serotypes bycarB-Based Oligonucleotide Microarray

2013 ◽  
Vol 80 (1) ◽  
pp. 366-373 ◽  
Author(s):  
Hwa Hui Shin ◽  
Byeong Hee Hwang ◽  
Jeong Hyun Seo ◽  
Hyung Joon Cha
Keyword(s):  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Detection System ◽  
Large Subunit ◽  
Cross Reactivity ◽  
Oligonucleotide Microarray ◽  
Carbamoyl Phosphate Synthetase ◽  
Carbamoyl Phosphate ◽  
Content Type ◽  
Contaminated Food

ABSTRACTIt is important to rapidly and selectively detect and analyze pathogenicSalmonella entericasubsp.entericain contaminated food to reduce the morbidity and mortality ofSalmonellainfection and to guarantee food safety. In the present work, we developed an oligonucleotide microarray containing duplicate specific capture probes based on thecarBgene, which encodes the carbamoyl phosphate synthetase large subunit, as a competent biomarker evaluated by genetic analysis to selectively and efficiently detect and discriminate threeS. entericasubsp.entericaserotypes: Choleraesuis, Enteritidis, and Typhimurium. Using the developed microarray system, three serotype targets were successfully analyzed in a range as low as 1.6 to 3.1 nM and were specifically discriminated from each other without nonspecific signals. In addition, the constructed microarray did not have cross-reactivity with other common pathogenic bacteria and even enabled the clear discrimination of the targetSalmonellaserotype from a bacterial mixture. Therefore, these results demonstrated that our novelcarB-based oligonucleotide microarray can be used as an effective and specific detection system forS. entericasubsp.entericaserotypes.

scholarly journals Packaging of Campylobacter jejuni into Multilamellar Bodies by the Ciliate Tetrahymena pyriformis

2016 ◽  
Vol 82 (9) ◽  
pp. 2783-2790 ◽  
Author(s):  
Hana Trigui ◽  
Valérie E. Paquet ◽  
Steve J. Charette ◽  
Sébastien P. Faucher
Keyword(s):  
Campylobacter Jejuni ◽  
Pathogenic Bacteria ◽  
Potable Water ◽  
Acanthamoeba Castellanii ◽  
Tetrahymena Pyriformis ◽  
Content Type ◽  
Multilamellar Bodies ◽  
Contaminated Food ◽  
Bacterial Gastroenteritis ◽  
Kinetics Of

ABSTRACTCampylobacter jejuniis the leading cause of bacterial gastroenteritis worldwide. Transmission to humans occurs through consumption of contaminated food or water. The conditions affecting the persistence ofC. jejuniin the environment are poorly understood. Some protozoa package and excrete bacteria into multilamellar bodies (MLBs). Packaged bacteria are protected from deleterious conditions, which increases their survival. We hypothesized thatC. jejunicould be packaged under aerobic conditions by the amoebaAcanthamoeba castellaniior the ciliateTetrahymena pyriformis, both of which are able to package other pathogenic bacteria.A. castellaniidid not produce MLBs containingC. jejuni. In contrast, when incubated withT. pyriformis,C. jejuniwas ingested, packaged in MLBs, and then expelled into the milieu. The viability of the bacteria inside MLBs was confirmed by microscopic analyses. The kinetics ofC. jejuniculturability showed that packaging increased the survival ofC. jejuniup to 60 h, in contrast to the strong survival defect seen in ciliate-free culture. This study suggests thatT. pyriformismay increase the risk of persistence ofC. jejuniin the environment and its possible transmission between different reservoirs in food and potable water through packaging.

scholarly journals Protozoan Cysts Act as a Survival Niche and Protective Shelter for Foodborne Pathogenic Bacteria

2015 ◽  
Vol 81 (16) ◽  
pp. 5604-5612 ◽  
Author(s):  
Ellen Lambrecht ◽  
Julie Baré ◽  
Natascha Chavatte ◽  
Wim Bert ◽  
Koen Sabbe ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Acanthamoeba Castellanii ◽  
Bacterial Survival ◽  
Free Living ◽  
Active Growth ◽  
Content Type ◽  
Foodborne Pathogenic Bacteria ◽  
Adverse Environmental Conditions ◽  
Species Specific

ABSTRACTThe production of cysts, an integral part of the life cycle of many free-living protozoa, allows these organisms to survive adverse environmental conditions. Given the prevalence of free-living protozoa in food-related environments, it is hypothesized that these organisms play an important yet currently underinvestigated role in the epidemiology of foodborne pathogenic bacteria. Intracystic bacterial survival is highly relevant, as this would allow bacteria to survive the stringent cleaning and disinfection measures applied in food-related environments. The present study shows that strains of widespread and important foodborne bacteria (Salmonella enterica,Escherichia coli,Yersinia enterocolitica, andListeria monocytogenes) survive inside cysts of the ubiquitous amoebaAcanthamoeba castellanii, even when exposed to either antibiotic treatment (100 μg/ml gentamicin) or highly acidic conditions (pH 0.2) and resume active growth in broth media following excystment. Strain- and species-specific differences in survival periods were observed, withSalmonella entericasurviving up to 3 weeks inside amoebal cysts. Up to 53% of the cysts were infected with pathogenic bacteria, which were located in the cyst cytosol. Our study suggests that the role of free-living protozoa and especially their cysts in the persistence and epidemiology of foodborne bacterial pathogens in food-related environments may be much more important than hitherto assumed.

scholarly journals Behavior of Yersinia enterocolitica in the Presence of the Bacterivorous Acanthamoeba castellanii

2013 ◽  
Vol 79 (20) ◽  
pp. 6407-6413 ◽  
Author(s):  
E. Lambrecht ◽  
J. Baré ◽  
I. Van Damme ◽  
W. Bert ◽  
K. Sabbe ◽  
...  
Keyword(s):  
Yersinia Enterocolitica ◽  
Pathogenic Bacteria ◽  
Acanthamoeba Castellanii ◽  
Ecological Niches ◽  
Free Living ◽  
Content Type ◽  
Food Borne ◽  
Transmission Electron ◽  
Set Up ◽  
The Impact

ABSTRACTFree-living protozoa play an important role in the ecology and epidemiology of human-pathogenic bacteria. In the present study, the interaction betweenYersinia enterocolitica, an important food-borne pathogen, and the free-living amoebaAcanthamoeba castellaniiwas studied. Several cocultivation assays were set up to assess the resistance ofY. enterocoliticatoA. castellaniipredation and the impact of environmental factors and bacterial strain-specific characteristics. Results showed that allY. enterocoliticastrains persist in association withA. castellaniifor at least 14 days, and associations withA. castellaniienhanced survival ofYersiniaunder nutrient-rich conditions at 25°C and under nutrient-poor conditions at 37°C. Amoebae cultivated in the supernatant of oneYersiniastrain showed temperature- and time-dependent permeabilization. Intraprotozoan survival ofY. enterocoliticadepended on nutrient availability and temperature, with up to 2.8 log CFU/ml bacteria displaying intracellular survival at 7°C for at least 4 days in nutrient-rich medium. Transmission electron microscopy was performed to locate theYersiniacells inside the amoebae. AsYersiniaandAcanthamoebashare similar ecological niches, this interaction identifies a role of free-living protozoa in the ecology and epidemiology ofY. enterocolitica.

scholarly journals Quinazoline-Based Antivirulence Compounds Selectively Target Salmonella PhoP/PhoQ Signal Transduction System

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
María Ayelén Carabajal ◽  
Christopher R. M. Asquith ◽  
Tuomo Laitinen ◽  
Graham J. Tizzard ◽  
Lucía Yim ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Catalytic Domain ◽  
Kinase Inhibitor ◽  
Adaptive Responses ◽  
Antibacterial Compounds ◽  
Content Type ◽  
Two Component ◽  
Serovar Typhimurium

ABSTRACT The rapid emergence of multidrug resistance among bacterial pathogens has become a significant challenge to human health in our century. Therefore, development of next-generation antibacterial compounds is an urgent need. Two-component signal transduction systems (TCS) are stimulus-response coupling devices that allow bacteria to sense and elaborate adaptive responses to changing environmental conditions, including the challenges that pathogenic bacteria face inside the host. The differential presence of TCS, present in bacteria but absent in the animal kingdom, makes them attractive targets in the search for new antibacterial compounds. In Salmonella enterica, the PhoP/PhoQ two-component system controls the expression of crucial phenotypes that define the ability of the pathogen to establish infection in the host. We now report the screening of 686 compounds from a GlaxoSmithKline published kinase inhibitor set in a high-throughput whole-cell assay that targets Salmonella enterica serovar Typhimurium PhoP/PhoQ. We identified a series of quinazoline compounds that showed selective and potent downregulation of PhoP/PhoQ-activated genes and define structural attributes required for their efficacy. We demonstrate that their bioactivity is due to repression of the PhoQ sensor autokinase activity mediated by interaction with its catalytic domain, acting as competitive inhibitors of ATP binding. While noncytotoxic, the hit molecules exhibit antivirulence effect by blockage of S. Typhimurium intramacrophage replication. Together, these features make these quinazoline compounds stand out as exciting leads to develop a therapeutic intervention to fight salmonellosis.

scholarly journals ElyC and Cyclic Enterobacterial Common Antigen Regulate Synthesis of Phosphoglyceride-Linked Enterobacterial Common Antigen

mBio ◽  
2021 ◽  
Author(s):  
Ashutosh K. Rai ◽  
Joseph F. Carr ◽  
David E. Bautista ◽  
Wei Wang ◽  
Angela M. Mitchell
Keyword(s):  
Klebsiella Pneumoniae ◽  
Yersinia Pestis ◽  
Outer Membrane ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Permeability Barrier ◽  
Common Antigen ◽  
Content Type ◽  
Enterobacterial Common Antigen ◽  
The Many

Enterobacterial common antigen (ECA) is a conserved polysaccharide present on the surface of the outer membrane (OM) and in the periplasm of the many pathogenic bacteria belonging to Enterobacterales , including Klebsiella pneumoniae , Salmonella enterica , and Yersinia pestis . As the OM is a permeability barrier that excludes many antibiotics, synthesis pathways for OM molecules are promising targets for antimicrobial discovery.

scholarly journals Endogenous Metabolites Released by Sanitized Sprouting Alfalfa Seed Inhibit the Growth of Salmonella enterica

mSystems ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Ga-Hee Ban ◽  
Yue Dai ◽  
Tao Huan ◽  
Alfred Ke ◽  
Pascal Delaquis ◽  
...  
Keyword(s):  
Food Safety ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
The United States ◽  
Antimicrobial Treatment ◽  
Human Consumption ◽  
Content Type ◽  
Alfalfa Seed ◽  
The Impact ◽  
Combinatorial Treatment

ABSTRACT Sprouts are the leading cause of foodborne disease outbreaks globally, mainly because the specialized conditions required to germinate seed sprouts for human consumption contribute to an environment that allows pathogenic bacteria to flourish. To reduce risk of illness, current food safety guidelines in the United States and Canada recommend hypochlorite treatment for seed sanitation. However, many growers and consumers have become wary of the impact of hypochlorite on human health and the environment and are actively seeking less caustic approaches. Here, we evaluated the effects of both the traditional hypochlorite treatment and a milder alternative on nontyphoidal Salmonella enterica colonization of germinating alfalfa seed. Moreover, we explored three biological factors as potential contributors for inhibition of S. enterica growth: colonization by indigenous bacteria, seed composition changes, and seed metabolite release. In this experimental setting, we found that a combinatorial treatment of heat, peroxide, and acetic acid was as effective as hypochlorite for inhibiting S. enterica growth. Notably, we pinpointed N-acetyl-spermidine as an endogenous metabolite exuded by treated seeds that strongly inhibits S. enterica growth. In doing so, we both elucidated one of the mechanisms of chemical sanitation and highlighted a potential seed-derived mode of antimicrobial treatment that may apply to modernized food safety protocols. IMPORTANCE Warm, humid, and nutrient-rich conditions that are used to produce sprouts encourage Salmonella enterica to proliferate. However, many disparate sanitation methods exist, and there is currently no single treatment that can guarantee pathogen-free seeds. Here, we compared the ability of traditional hypochlorite treatment against a combinatorial treatment of heat, peroxide, and vinegar (HPA) commonly used in organic farming practices to inhibit S. enterica colonization and growth during alfalfa germination and found HPA to be at least as effective. Furthermore, we explored seed-based changes following sanitization treatments using metabolomics and identified polyamines as strong inhibitors of Salmonella growth on germinating alfalfa. Our findings enable a better understanding of host-pathogen interactions in sprout microbial communities and promote in-depth, evidence-based research in seed sprout safety.

scholarly journals Draft Genome Sequences of 112 Salmonella enterica Serovar Dublin Strains Isolated from Humans and Animals in Brazil

2018 ◽  
Vol 6 (24) ◽  
Author(s):  
Fábio Campioni ◽  
Felipe Pinheiro Vilela ◽  
Guojie Cao ◽  
George Kastanis ◽  
Daniela Miller ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Systemic Disease ◽  
Draft Genome ◽  
Genome Sequences ◽  
Content Type ◽  
Salmonella Enterica Serovar Dublin

ABSTRACT Salmonella enterica serovar Dublin is a strongly adapted serovar that causes enteritis and/or systemic disease in cattle and results in high rates of mortality. Here, we report the draft genome sequences of 112 S. Dublin strains isolated from humans and animals in Brazil. These draft genome sequences will help enhance our understanding of this serovar in Brazil.

scholarly journals Persistent Infection and Long-Term Carriage of Typhoidal and Nontyphoidal Salmonellae

2018 ◽  
Vol 32 (1) ◽  
Author(s):  
Ohad Gal-Mor
Keyword(s):  
Persistent Infection ◽  
Salmonella Enterica ◽  
Host Response ◽  
Pathogenic Bacteria ◽  
Current Knowledge ◽  
Laboratory Diagnosis ◽  
Human Pathogens ◽  
Content Type ◽  
Persistent Infections

SUMMARYThe ability of pathogenic bacteria to affect higher organisms and cause disease is one of the most dramatic properties of microorganisms. Some pathogens can establish transient colonization only, but others are capable of infecting their host for many years or even for a lifetime. Long-term infection is called persistence, and this phenotype is fundamental for the biology of important human pathogens, includingHelicobacter pylori,Mycobacterium tuberculosis, andSalmonella enterica. Both typhoidal and nontyphoidal serovars of the speciesSalmonella entericacan cause persistent infection in humans; however, as these twoSalmonellagroups cause clinically distinct diseases, the characteristics of their persistent infections in humans differ significantly. Here, following a general summary ofSalmonellapathogenicity, host specificity, epidemiology, and laboratory diagnosis, I review the current knowledge aboutSalmonellapersistence and discuss the relevant epidemiology of persistence (including carrier rate, duration of shedding, and host and pathogen risk factors), the host response toSalmonellapersistence,Salmonellagenes involved in this lifestyle, as well as genetic and phenotypic changes acquired during prolonged infection within the host. Additionally, I highlight differences between the persistence of typhoidal and nontyphoidalSalmonellastrains in humans and summarize the current gaps and limitations in our understanding, diagnosis, and curing of persistentSalmonellainfections.

scholarly journals Bistable Expression of CsgD in Salmonella enterica Serovar Typhimurium Connects Virulence to Persistence

2015 ◽  
Vol 83 (6) ◽  
pp. 2312-2326 ◽  
Author(s):  
Keith D. MacKenzie ◽  
Yejun Wang ◽  
Dylan J. Shivak ◽  
Cynthia S. Wong ◽  
Leia J. L. Hoffman ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Single Cells ◽  
Smooth Transition ◽  
Intestinal Cell ◽  
Planktonic Cells ◽  
Multicellular Aggregate ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Cell Subpopulations

Pathogenic bacteria often need to survive in the host and the environment, and it is not well understood how cells transition between these equally challenging situations. For the human and animal pathogenSalmonella entericaserovar Typhimurium, biofilm formation is correlated with persistence outside a host, but the connection to virulence is unknown. In this study, we analyzed multicellular-aggregate and planktonic-cell subpopulations that coexist whenS. Typhimurium is grown under biofilm-inducing conditions. These cell types arise due to bistable expression of CsgD, the central biofilm regulator. Despite being exposed to the same stresses, the two cell subpopulations had 1,856 genes that were differentially expressed, as determined by transcriptome sequencing (RNA-seq). Aggregated cells displayed the characteristic gene expression of biofilms, whereas planktonic cells had enhanced expression of numerous virulence genes. Increased type three secretion synthesis in planktonic cells correlated with enhanced invasion of a human intestinal cell line and significantly increased virulence in mice compared to the aggregates. However, when the same groups of cells were exposed to desiccation, the aggregates survived better, and the competitive advantage of planktonic cells was lost. We hypothesize that CsgD-based differentiation is a form of bet hedging, with single cells primed for host cell invasion and aggregated cells adapted for persistence in the environment. This allowsS. Typhimurium to spread the risks of transmission and ensures a smooth transition between the host and the environment.

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