Molecular Characteristics of Novel Phage vB_ShiP-A7 Infecting Multidrug-Resistant Shigella flexneri and Escherichia coli, and Its Bactericidal Effect in vitro and in vivo

Xu, Jianping; Zhang, Ruiyang; Yu, Xinyan; Zhang, Xuesen; Liu, Gen-Yan; Liu, Xiaoqiu

doi:10.3389/fmicb.2021.698962

Cited by 9 publications

(7 citation statements)

References 53 publications

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“…In general, a high burst value leads to higher lytic activity [21], a wanted feature in phages that will be used in biocontrol applications. In agreement with our findings, similar results were observed by Xu and coworkers for the Shigella phage vB_ShiP-A7 (100 PFU cell −1 , latent period of 35 min) [22] and by Ahamed et al [23] for Sfin-1 (28 PFU cell −1 , latent period of 5 min). On the contrary, several authors found phages with a high burst value and a short latent period such as phage vBSdyS-ISF003 (128 PFU cell −1 , 10 min) [24] and phage 2019SD1 (151 PFU cell −1 , 20 min) [20], and phages with a low burst value with a long latent period, e.g., phage pSf-2 (16 PFU cell −1 , 30 min) [19] and SGF2 (38 PFU cell −1 , 40 min) [25].…”

Section: Discussionsupporting

confidence: 94%

Influence of Physicochemical Factors on Adsorption of Ten Shigella flexneri Phages

Tomat

Aquili

Casabonne

et al. 2022

Viruses

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Bacterial viruses known as bacteriophages have been demonstrated to be effective in killing foodborne pathogens such as Shigella flexneri. Adsorption is the first step in the phage–host interaction. In the present work, 10 Shigella phages were used to characterize the adsorption process on Shigella flexneri ATCC12022 in several physicochemical conditions related to food and in a food matrix. One-step growth curves were drawn for all the Shigella-phages evaluated. Furthermore, the adsorption rate for each of the 10 phages was determined. In addition, the influence of temperature, Na+, Mg2+, pH, sucrose and glycerol on phage adsorption was investigated. Two phages (Shi22 and Shi30) showed higher burst sizes values (67 and 64 PFU cell−1, respectively) and burst times of 25 min to 30 min, while the other eight phages exhibited burst sizes ranging from 14 to 17 PFU cell−1 with slower burst times. Furthermore, most phages achieved a high adsorption rate, and the adsorption constants (k) ranged from ~10−9 to 10−10 mL min−1. Regarding the influence of temperature, cations and pH, a high or moderate percentage of adsorption was observed for most of the phages evaluated. The adsorption decreased at increasing concentrations of Na+, sucrose and glycerol, although at different levels, since adsorption was more affected by sucrose than by glycerol and Na+ for most phages. The adsorption obtained in Triptein soy broth (TSB) for most of the phages/strain systems evaluated was moderate or high, as well as those observed in a food matrix. Thus, our phages could potentially be used to improve food safety under a wide range of environmental conditions against foodborne pathogens.

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Section: Discussionsupporting

confidence: 94%

Influence of Physicochemical Factors on Adsorption of Ten Shigella flexneri Phages

Tomat

Aquili

Casabonne

et al. 2022

Viruses

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“…Similar results were obtained by other authors when they evaluated resistance of S. flexneri (Mallick et al, 2021; Shahin & Bouzari, 2018; Zhang et al, 2012) and S. dysenteriae (Kumar et al, 2021) phages at 40 and 50°C. In contrast, another phage lytic against S. flexneri was almost completely inactivated at 50°C (Xu et al, 2021). At 60°C, seven of the ten phages evaluated showed significant reductions, though the other three, namely Shi30, Shi33, and Shi93, showed a higher resistance even at 70°C.…”

Section: Resultsmentioning

confidence: 99%

“…Although many authors have studied phage viability at various physicochemical conditions such as thermal treatments (Jamal et al, 2015; Xu et al, 2021), varying pH (Mallick et al, 2021; Zhang et al, 2012), and salt concentrations (Kumar et al, 2021; Shahin & Bouzari, 2018), the activity of phage/ Shigella systems has never been evaluated in physicochemical conditions similar to those found in food matrices. Moreover, even though many phage–host studies have been previously performed, those focusing on Shigella strains have been scarcely documented.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical characterization of ten newly isolated phages against the foodborne pathogen Shigella flexneri

Tomat

González

Aquili

et al. 2022

Food Processing Preservation

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Ten bacteriophages with lytic activity against Shigella flexneri were tested for their resistance to physicochemical conditions found in food matrices. Phage viability and activity were evaluated at different temperatures, pH values, and NaCl concentrations.In addition, challenge tests with each individual phage against ATCC 12022 were conducted to evaluate their use as biocontrol agents. Although phages showed high resistance up to 60°C, Shi30, Shi33, and Shi93 showed higher thermal resistance (70°C).The ten phages endured pH treatments, being more resistant to alkaline conditions. The NaCl concentrations evaluated showed no significant influence on phage counts. Furthermore, challenge tests against ATCC 12022 resulted in significant CFU ml −1 reductions. The results showed that the phages evaluated were resistant to a wide range of temperatures and pH and to all the concentrations of NaCl tested. Therefore, the phages evaluated in this study could potentially be used with biocontrol purposes in various food matrices prior further characterization.Novelty impact statement: Ten newly isolated phages against the foodborne pathogen Shigella flexneri remained viable after different physicochemical treatments. Furthermore, their activity was maintained after thermal and chemical treatments. Also, the ten phages were effective against pathogenic Shigella flexneri strains in challenge tests.

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“…The experiment was repeated thrice, and one-step growth curves were plotted using GraphPad Prism 8 (San Diego, CA, USA) software. The burst size of the phage is equal to the amount of phage at the end of lysis divided by the initial number of bacterial cells at the time of infection ( Xu et al, 2021 ).…”

Section: Methodsmentioning

confidence: 99%

Topically applied bacteriophage to control multi-drug resistant Pseudomonas aeruginosa-infected wounds in a New Zealand rabbit model

Wang

Meng²,

Zhang³

et al. 2022

Front. Microbiol.

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Pseudomonas aeruginosa (P. aeruginosa) is a widespread, gram-negative, pathogenic bacterium that causes serious internal and external infections in humans and other animals. The increasing antibiotic resistance has complicated bacterial infection treatment, and current antibiotic therapies cannot cure all infections. Owing to this, bacteriophages (phages) have regained attention as potential therapeutics for bacterial infections. In this study, the phage “PaVOA” was isolated from hospital sewage and characterized. Next, a New Zealand rabbit skin infection model was used to determine the therapeutic efficacy of PaVOA as compared to a phage cocktail or the cephalosporin antibiotic ceftriaxone. Characterization results demonstrated that phage PaVOA belongs to the Myoviridae family, has a double-stranded DNA genome, is resistant to low temperatures (−20°C), is most optimal at 40°C, has good acid–base tolerance, and remains stable for 30 min under 20 W ultraviolet (UV) intensity. The optimal multiplicity of infection of PaVOA was 0.1, and a one-step growth curve showed a short latency period (10 min), thus demonstrating its ability to rapidly kill bacteria. Furthermore, the addition of calcium (Ca) and magnesium (Mg) ions significantly increased the PaVOA titer. An in vivo phage kinetic curve showed that PaVOA was rapidly inactivated within the blood of New Zealand rabbits (undetectable after 12 h), and no animals died due to phage treatment. Wound healing studies showed that the phage cocktail induced a high healing rate and an acceleration of the skin remodeling process, and was more efficacious than ceftriaxone. Therefore, phage cocktail therapy represents a novel therapeutic approach in the treatment of traumatic skin infections caused by multi-drug resistant P. aeruginosa.

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Molecular Characteristics of Novel Phage vB_ShiP-A7 Infecting Multidrug-Resistant Shigella flexneri and Escherichia coli, and Its Bactericidal Effect in vitro and in vivo

Cited by 9 publications

References 53 publications

Influence of Physicochemical Factors on Adsorption of Ten Shigella flexneri Phages

Influence of Physicochemical Factors on Adsorption of Ten Shigella flexneri Phages

Physicochemical characterization of ten newly isolated phages against the foodborne pathogen Shigella flexneri

Topically applied bacteriophage to control multi-drug resistant Pseudomonas aeruginosa-infected wounds in a New Zealand rabbit model

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