Expression of <i>hilA</i> in Response to Mild Acid Stress in <i>Salmonella enterica</i> is Serovar and Strain Dependent

González-Gil, Francisco; Bolloch, Alexandre Le; Pendleton, Sean; Zhang, Nan; Wallis, Audra; Hanning, Irene

doi:10.1111/j.1750-3841.2012.02684.x

Cited by 18 publications

(19 citation statements)

References 29 publications

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“…The second virulence gene evaluated in this study, hilA, regulates the expression of invasion genes in response to environmental stimuli including osmolarity, oxygen levels, and pH (Durant et al, 2000;Fluit, 2005;Chuanchuen et al, 2010;Park et al, 2011;Gonzalez-Gil et al, 2012). In the present study, there was an overall negative correlation between survival and upregulation of these 2 genes indicating that perhaps efforts for virulence were shifted away from these genes and instead focused on upregulation of stress responses (Gonzalez-Gil et al, 2012).…”

Section: Discussionmentioning

confidence: 73%

“…All quantitative reverse-transcription real-time PCR (qRT-PCR) reactions were performed as described by Gonzalez-Gil et al (2012) using the ABI 7100 RT-PCR system (Applied Biosystems, Carlsbad, CA). Briefly, a 20-µL total volume consisted of 10 µL of Power SYBR Green PCR Master Mix (Life Technologies Corporation, Carlsbad, CA), 300 nM of each primer, 100 ng of cDNA template, and water to volume.…”

Section: Quantitative Reverse-transcription Real-time Pcrmentioning

confidence: 99%

“…Total RNA was isolated from the samples as described by Gonzalez-Gil et al (2012) with some modification. At specific time points (0, 4, 8, and 24 h) and equal volume of RNA protect bacterial reagent (Qiagen, Valencia, CA) was added to a 2-mL microfuge tube containing the Salmonella feed suspensions and allowed to stand at room temperature for 5 min.…”

Section: Rna Preparationmentioning

confidence: 99%

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Survival of Salmonella enterica in poultry feed is strain dependent

et al. 2014

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Feed components have low water activity, making bacterial survival difficult. The mechanisms of Salmonella survival in feed and subsequent colonization of poultry are unknown. The purpose of this research was to compare the ability of Salmonella serovars and strains to survive in broiler feed and to evaluate molecular mechanisms associated with survival and colonization by measuring the expression of genes associated with colonization (hilA, invA) and survival via fatty acid synthesis (cfa, fabA, fabB, fabD). Feed was inoculated with 1 of 15 strains of Salmonella enterica consisting of 11 serovars (Typhimurium, Enteriditis, Kentucky, Seftenburg, Heidelberg, Mbandanka, Newport, Bairely, Javiana, Montevideo, and Infantis). To inoculate feed, cultures were suspended in PBS and survival was evaluated by plating samples onto XLT4 agar plates at specific time points (0 h, 4 h, 8 h, 24 h, 4 d, and 7 d). To evaluate gene expression, RNA was extracted from the samples at the specific time points (0, 4, 8, and 24 h) and gene expression measured with real-time PCR. The largest reduction in Salmonella occurred at the first and third sampling time points (4 h and 4 d) with the average reductions being 1.9 and 1.6 log cfu per g, respectively. For the remaining time points (8 h, 24 h, and 7 d), the average reduction was less than 1 log cfu per g (0.6, 0.4, and 0.6, respectively). Most strains upregulated cfa (cyclopropane fatty acid synthesis) within 8 h, which would modify the fluidity of the cell wall to aid in survival. There was a weak negative correlation between survival and virulence gene expression indicating downregulation to focus energy on other gene expression efforts such as survival-related genes. These data indicate the ability of strains to survive over time in poultry feed was strain dependent and that upregulation of cyclopropane fatty acid synthesis and downregulation of virulence genes were associated with a response to desiccation stress.

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Section: Discussionmentioning

confidence: 73%

Section: Quantitative Reverse-transcription Real-time Pcrmentioning

confidence: 99%

Section: Rna Preparationmentioning

confidence: 99%

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Survival of Salmonella enterica in poultry feed is strain dependent

et al. 2014

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“…Using quantitative reverse transcriptase real-time PCR, Gonzalez-Gil et al reported that expression of the virulence gene regulator hilA was both serovar and strain dependent when isolates were exposed to either mild acetic or HCl acid stress. Responses were dependent on the type of acid used and were time dependent, with hilA being upregulated after a 2-h exposure to the respective acid (350). When Milillo et al compared S. Typhimurium transcriptome responses to sodium acetate and sodium propionate exposure after 1 min (55°C at pH 4.0), the respective gene expression patterns were similar, with no increases in expression levels of rpoS, phoPQ, or virulence factors despite their established roles in organic and inorganic acid stress (35,327,328,338).…”

Section: Salmonella Virulence Response and Organic Acidsmentioning

confidence: 99%

Salmonella Pathogenicity and Host Adaptation in Chicken-Associated Serovars

Foley

Johnson

Ricke

et al. 2013

Microbiol Mol Biol Rev

263

218

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SUMMARY Enteric pathogens such as Salmonella enterica cause significant morbidity and mortality. S. enterica serovars are a diverse group of pathogens that have evolved to survive in a wide range of environments and across multiple hosts. S. enterica serovars such as S . Typhi, S . Dublin, and S . Gallinarum have a restricted host range, in which they are typically associated with one or a few host species, while S . Enteritidis and S . Typhimurium have broad host ranges. This review examines how S. enterica has evolved through adaptation to different host environments, especially as related to the chicken host, and continues to be an important human pathogen. Several factors impact host range, and these include the acquisition of genes via horizontal gene transfer with plasmids, transposons, and phages, which can potentially expand host range, and the loss of genes or their function, which would reduce the range of hosts that the organism can infect. S . Gallinarum, with a limited host range, has a large number of pseudogenes in its genome compared to broader-host-range serovars. S. enterica serovars such as S . Kentucky and S . Heidelberg also often have plasmids that may help them colonize poultry more efficiently. The ability to colonize different hosts also involves interactions with the host's immune system and commensal organisms that are present. Thus, the factors that impact the ability of Salmonella to colonize a particular host species, such as chickens, are complex and multifactorial, involving the host, the pathogen, and extrinsic pressures. It is the interplay of these factors which leads to the differences in host ranges that we observe today.

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“…In their research, González et al (2012) compared hilA gene expression in response to acid stress between different Salmonella serovars and strains. Results showed that there are serovar and strain differences in virulence gene expression and acid tolerance; regulation of hilA showed to be serovar and strain dependent as well as dependent on acid type (González et al, 2012). In an extensive genome analysis comparison between UK-1 and other S. Typhimurium strains, Luo et al (2012) reported that virulence factors pertaining to one strain might increase or decrease virulence when present in a different strain.…”

Section: Resultsmentioning

confidence: 99%

Salmonella Heidelberg Strain Responses to Essential Oil Components

Calo¹,

Baker²,

Park³

et al. 2015

JFR

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Salmonella are one of the more prominent foodborne pathogens that represent a major health risk to humans. Salmonella serovar Heidelberg strains are increasingly becoming an important public health concern, since they have been identified as one of the primary Salmonella serovars responsible for human outbreaks. Over the years, Salmonella Heidelberg isolates have exhibited higher rates of resistance to multiple antimicrobial agents compared to other Salmonella serovars. Essential oils (EOs) have been widely used as alternatives to chemical-based antimicrobials. In the current research, five EOs were screened to determine their antimicrobial activity against 15 S. Heidelberg strains from different sources. Oils tested were R(+)-limonene, orange terpenes, cold compressed orange oil, trans-cinnamaldehyde and carvacrol. EOs were stabilized in nutrient broth by adding 0.15% (w/v) agar. Tube dilution assays and minimal inhibitory concentrations (MIC) were determined by observing color changes in samples during exposure to EOs. Carvacrol and trans-cinnamaldehyde completely inhibited the growth of S. Heidelberg strains, while R(+)-limonene and orange terpenes did not show any inhibitory activity against the strains tested. Cold compressed orange oil only inhibited growth of two of the strains exhibiting an MIC of 1%. All S. Heidelberg isolates evaluated exhibited similar responses to the respective EOs. The use of all natural antimicrobials such as specific EOs offers the potential to limit the majority of S. Heidelberg isolates that may occur in food production.

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Expression of hilA in Response to Mild Acid Stress in Salmonella enterica is Serovar and Strain Dependent

Cited by 18 publications

References 29 publications

Survival of Salmonella enterica in poultry feed is strain dependent

Survival of Salmonella enterica in poultry feed is strain dependent

Salmonella Pathogenicity and Host Adaptation in Chicken-Associated Serovars

Salmonella Heidelberg Strain Responses to Essential Oil Components

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