SPI-9 of Salmonella enterica serovar Typhi is constituted by an operon positively regulated by RpoS and contributes to adherence to epithelial cells in culture

Velásquez, Juan D.; Hidalgo, Alejandro A.; Villagra, Nicolás A.; Santiviago, Carlos A.; Mora, Gabriela; Fuentes, Juan A.

doi:10.1099/mic.0.000319

Cited by 32 publications

(24 citation statements)

References 55 publications

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“…Adhesion of pathogenic bacteria to the mucus of host animals is often the initial step of infection (Cai et al., ). As one of the key virulence factors, although the adherence pattern in E. coli and Salmonella enterica serovar Typhi was proved to be regulated by rpoS (Adnan et al., ; Velásquez et al., ), the function of rpoS in the V. alginolyticus adhesion regulation was never concerned. In the present study, after stable gene knockdown, the mRNA level of rpoS was markedly impaired as well as adhesion in V. alginolyticus .…”

Section: Discussionmentioning

confidence: 99%

The role of rpoS in the regulation of Vibrio alginolyticus virulence and the response to diverse stresses

Huang

Guo

et al. 2019

Journal of Fish Diseases

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Vibrio alginolyticus is a leading aquatic pathogen, causing huge losses to aquaculture. rpoS has been proven to play a variety of important roles in stress response and virulence in several bacteria. In our previous study, upon treatment with Cu2+, Pb2+, Hg2+ and low pH, the expression levels of rpoS were downregulated as assessed by RNA‐seq, while impaired adhesion ability was observed, indicating that rpoS might play roles in the regulation of adhesion. In the present study, the RNAi technology was used to knockdown rpoS in V. alginolyticus. In comparison with wild‐type V. alginolyticus, RNAi‐treated bacteria showed significantly impaired abilities of adhesion, growth, haemolytic, biofilm production, movement and virulence. Meanwhile, alterations of temperature, salinity, pH and starvation starkly affected rpoS expression. The present data suggested that rpoS is a critical regulator of virulence in V. alginolyticus; in addition, rpoS regulates bacterial adhesion in response to temperature, pH and nutrient content changes. These are helpful to explore its pathogenic mechanism and provide reference for disease control.

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Section: Discussionmentioning

confidence: 99%

The role of rpoS in the regulation of Vibrio alginolyticus virulence and the response to diverse stresses

Huang

Guo

et al. 2019

Journal of Fish Diseases

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“…Typhimurium, SPI-9, encoding a type I secretion system, was reported to contribute to the adhesion of S . Typhi to epithelial cells [18], and biofilm formation and invasion in S . Enteritidis [19].…”

Section: Introductionmentioning

confidence: 99%

Signal transduction pathway mediated by the novel regulator LoiA for low oxygen tension induced Salmonella Typhimurium invasion

et al. 2017

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Salmonella enterica serovar Typhimurium (S. Typhimurium) is a major intestinal pathogen of both humans and animals. Salmonella pathogenicity island 1 (SPI-1)-encoded virulence genes are required for S. Typhimurium invasion. While oxygen (O2) limitation is an important signal for SPI-1 induction under host conditions, how the signal is received and integrated to the central SPI-1 regulatory system in S. Typhimurium is not clear. Here, we report a signal transduction pathway that activates SPI-1 expression in response to low O2. A novel regulator encoded within SPI-14 (STM14_1008), named LoiA (low oxygen induced factor A), directly binds to the promoter and activates transcription of hilD, leading to the activation of hilA (the master activator of SPI-1). Deletion of loiA significantly decreased the transcription of hilA, hilD and other representative SPI-1 genes (sipB, spaO, invH, prgH and invF) under low O2 conditions. The response of LoiA to the low O2 signal is mediated by the ArcB/ArcA two-component system. Deletion of either arcA or arcB significantly decreased transcription of loiA under low O2 conditions. We also confirmed that SPI-14 contributes to S. Typhimurium virulence by affecting invasion, and that loiA is the virulence determinant of SPI-14. Mice infection assays showed that S. Typhimurium virulence was severely attenuated by deletion of either the entire SPI-14 region or the single loiA gene after oral infection, while the virulence was not affected by either deletion after intraperitoneal infection. The signal transduction pathway described represents an important mechanism for S. Typhimurium to sense and respond to low O2 conditions of the host intestinal tract for invasion. SPI-14-encoded loiA is an essential element of this pathway that integrates the low O2 signal into the SPI-1 regulatory system. Acquisition of SPI-14 is therefore crucial for the evolution of S. Typhimurium as an intestinal pathogen.

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“…While BIg28 is likely most distal to the outer membrane core, BIg1 is most proximal to the outer membrane and less likely to contact potential ligands. Moreover, bapABCD is highly conserved among S. enterica serovars (with some variations in bapA ) indicating an important purpose during S. enterica lifestyle (47). Contribution of BapA encoded by other S. enterica serovars in adhesion to various salad species has to be tested in addition to the influence of longer infection times and involvement of BapA affecting biofilm formation on salad leaves.…”

Section: Discussionmentioning

confidence: 99%

Factors required for adhesion ofSalmonella entericaserovar Typhimurium to lettuce (Lactuca sativa)

Hensel

Elpers

2020

Preprint

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Salmonella enterica serovar Typhimurium (STM) is a major cause of food-borne gastroenteritis. Recent outbreaks of infections by STM are often associated with non-animal related food, i.e. vegetables, fruits, herbs, sprouts and nuts. One main problem related to consumption of fresh produce is the minimal processing, especially for leafy salads such as corn salad, rocket salad, or lettuce. In this study, we focused on lettuce (Lactuca sativa) which is contaminated by STM at higher rates compared to corn salad, resulting in prolonged persistence. We previously described the contribution of Saf fimbriae, type 1 secretion system (T1SS)-secreted BapA, intact LPS, and flagella-mediated motility to adhesion to corn salad leaves. We systematically analyzed factors contributing to adhesion of STM to lettuce leaves. We used the previously established reductionist, synthetic approach to identify factors that contribute to the surface binding of STM to leaves of lettuce by expressing all known adhesive structure by the Tet-on system. The analyses revealed contributions of Lpf fimbriae, Sti fimbriae, autotransported adhesin MisL, T1SS-secreted BapA, intact LPS, and flagella-mediated motility to adhesion of STM to lettuce leaves. In addition, we identified BapA is a potential adhesin involved in binding to corn salad and lettuce leaf surfaces.ImportanceGastrointestinal pathogens can be transmitted by animal products, as well as by fresh produce of non-animal origin. The numbers of outbreaks by fresh produce contaminated with gastrointestinal pathogens are increasing, and underline the relevance to human health. The mechanisms involved in the colonization of, persistence on, and transmission by fresh produce are poorly understood and have to be part of further research. Here, we investigated the contribution of adhesive factors of STM in the initial phase of plant colonization, i.e. the binding to the plant surface. Usage of a reductionist, synthetic approach including the controlled surface expression of specific adhesive structures of STM, one at a time, allowed the determination of relevant fimbrial and non-fimbrial adhesins, the O-antigen of lipopolysaccharide, the flagella, and chemotaxis to binding to lettuce leaves.

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SPI-9 of Salmonella enterica serovar Typhi is constituted by an operon positively regulated by RpoS and contributes to adherence to epithelial cells in culture

Cited by 32 publications

References 55 publications

The role of rpoS in the regulation of Vibrio alginolyticus virulence and the response to diverse stresses

The role of rpoS in the regulation of Vibrio alginolyticus virulence and the response to diverse stresses

Signal transduction pathway mediated by the novel regulator LoiA for low oxygen tension induced Salmonella Typhimurium invasion

Factors required for adhesion ofSalmonella entericaserovar Typhimurium to lettuce (Lactuca sativa)

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