Induction of the viable but nonculturable state of Salmonella enterica serovar Enteritidis deficient in (p)ppGpp synthesis

Rodrigues, Ramila Cristiane; Martins, Evandro Paulo Soares; Vanetti, Maria Cristina Dantas; Pinto, Uelinton Manoel; Santos, Marcilene dos

doi:10.1007/s13213-015-1057-6

Cited by 8 publications

(7 citation statements)

References 26 publications

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“…These authors considered that the time to Salmonella Typhimurium DT104 reach the VBNC state was higher than values previously reported with other Gramnegative enteric bacteria and attributed this result to the greater resilience of this serovar. The serovar PT4 578 of Salmonella Enteritidis maintained in PBS buffer with 0.6 M NaCl at 4°C reaches the VBNC state in 140 days [15], while Salmonella Typhimurium in VBNC state was obtained using residual water at 15 and 28°C after 200 days [23].…”

Section: Discussionmentioning

confidence: 99%

“…The viability of Salmonella cells on VBNC state was determined immediately after the culturability loss was detected in BHI broth and agar by culture-independent methods. The Live/Dead® BacLight™ (Invitrogen, OR, USA) kit and a fluorescence microscope were used [15,20]. Aliquots of 2 mL of cells submitted to different treatments to induce the VBNC status were centrifuged at 5000xg for 15 min at 4 ± 1°C, and to the pellet, 3 μL of Syto 9 and propidium iodide were added.…”

Section: Culturability and Cell Viability Assaymentioning

confidence: 99%

“…After the final wash, aliquots of 10 μL were placed onto sterilized glass slides (1 cm × 1 cm). The slides were air-dried in a laminar flow hood for adhesion of the cells [15].…”

Section: Morphology Evaluation Of Salmonella Cells In a Vbnc Status Bmentioning

confidence: 99%

“…The VBNC state is induced by several environmental factors, such as lack of nutrients, increase or decrease in temperature, or presence of antimicrobials, such as antibiotics, disinfectants, and sanitizers [13,14]. The entry in VNBC is accompanied by various cellular changes, such as reducing metabolic activity and gene expression, and morphological changes to allow its survival in the undergone adverse conditions [9,[14][15][16]. These physiological adaptations require a variable response time, depending on the intensity and abruptness of exposure to the stress-inducing factor(s).…”

Section: Introductionmentioning

confidence: 99%

“…Salmonella entry into VBNC state as a response to various stress conditions, such as nutritional [15,[17][18][19][20], low temperature [18,20], acid [21], osmotic [7,19] and, oxidative substances and sanitizers [22,23]. Disinfection or inactivation treatments such as the pulsed electric field [24], ultraviolet (UV) radiation [25], and copper sulfate [20] have also been linked to the induction VBNC state in Salmonella.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of stress conditions to induce viable but non-cultivable state in Salmonella

et al. 2020

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Salmonella can enter on the viable but non-culturable state (VBNC), characterized by the loss of ability to grow in routine culture media hindering detection by conventional methods and underestimation of the pathogen. Despite advances in research done so far, studies comparing conditions that lead Salmonella into the VBNC state are scarce. The main objective of this study was to evaluate different stresses to induce Salmonella to the VNBC state. Osmotic (1.2 M NaCl), acid (peracetic acid, 5.66 mg/mL) and oxidative (hydrogen peroxide, 1.20 mg/mL) stress were used at 4°C to induce Salmonella enterica serovars Enteritidis and Typhimurium to the VBNC state. The culturability loss was monitored in the brain heart infusion (BHI) broth and agar, and the viability was determined by fluorescence microscopy, using the Live/Dead® kit, and by flow cytometry. Besides, the morphological characterization by atomic force microscopy (AFM) was performed. Storage in 1.2 M NaCl at 4°C induced the VBNC state in Salmonella cells for periods longer than 121 days, and the percentage of viable cells has reached above 80.9%. More aggressive stress conditions promoted by peracetic acid and hydrogen peroxide induced the VBNC state in periods of, at most 0.14 day, and resulted in percentages of 8.5% to 45.5% viable cells, respectively. The counts of viable cells in the flow cytometer corroborate the results obtained by microscopic counts. The VBNC cells obtained in 1.2 M NaCl at 4°C showed morphological changes, reducing the size and changing the morphology from bacillary to coccoid. No morphological change was observed on the cells stressed by acid or oxidant compounds.

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Section: Discussionmentioning

confidence: 99%

Section: Culturability and Cell Viability Assaymentioning

confidence: 99%

“…After the final wash, aliquots of 10 μL were placed onto sterilized glass slides (1 cm × 1 cm). The slides were air-dried in a laminar flow hood for adhesion of the cells [15].…”

Section: Morphology Evaluation Of Salmonella Cells In a Vbnc Status Bmentioning

confidence: 99%