Temperature shock, injury and transient sensitivity to nisin in Gram negatives

Boziaris, Ioannis S.; Adams, M. R.

doi:10.1046/j.1365-2672.2001.01433.x

Cited by 50 publications

(27 citation statements)

References 30 publications

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“…Furthermore, the high MccJ25 concentration required to inhibit S. Typhimurium growth at low pH or within macrophages is indicative of the unspecific nature of the antibiotic uptake. Our interpretation is supported by the observation that a variety of stresses can produce a modification in the outer membrane barrier of Gram-negative bacteria [12-15]. Alakomi et al [16] reported that lactic acid (pH 4) was capable of permeabilizing E. coli , Pseudomonas aeruginosa and S. Typhimurium by disrupting the outer membrane.…”

Section: Resultssupporting

confidence: 74%

Macrophage environment turns otherwise MccJ25-resistant Salmonella into sensitive

et al. 2013

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BackgroundMicrocin J25 (MccJ25) is a plasmid-encoded antibiotic peptide produced by Escherichia coli (E. coli). MccJ25 enters into the sensitive E. coli strains by the outer membrane receptor FhuA and the inner membrane proteins TonB, ExbB, ExbD and SbmA. The resistance of Salmonella enterica serovar Typhimurium (S. Typhimurium) to MccJ25 is attributed to the inability of its FhuA protein to incorporate the antibiotic into the cell.ResultsIn this work we demonstrate that S. Typhimurium becomes notably susceptible to MccJ25 when replicating within macrophages. In order to determine the possible cause of this phenomenon, we studied the sensitivity of S. Typhimurium to MccJ25 at conditions resembling those of the internal macrophage environment, such as low pH, low magnesium and iron deprivation. We observed that the strain was only sensitive to the antibiotic at low pH, leading us to attribute the bacterial sensitization to this condition. A MccJ25-resistant E. coli strain in which fhuA is deleted was also inhibited by the antibiotic at low pH. Then, we could assume that the MccJ25 sensitivity change observed in both E. coli fhuA and S. Typhimurium is mediated by a MccJ25 uptake independent of the FhuA receptor. Moreover, low pH incubation also sensitized S. Typhimurium to the hydrophobic antibiotic novobiocin, which does not affect enteric bacteria viability because it is unable to penetrate the bacterial outer membrane. This observation supports our hypothesis about low pH producing a modification in the bacterial membrane permeability that allows an unspecific MccJ25 uptake. On the other hand, MccJ25 inhibited S. Typhimurium when cells were preincubated in acidic pH medium and then treated at neutral pH with the antibiotic.ConclusionsOur results suggest that acidic condition does not alter MccJ25 hydrophobicity but irreversibly modifies bacterial membrane permeability. This would allow an unspecific antibiotic uptake into the cell.From our data it is possible to infer that intracellular pathogenic strains, which are in vitro resistant to MccJ25, could become susceptible ones in vivo. Therefore, the MccJ25 action spectrum would be broader than what in vitro experiments indicate.

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Section: Resultssupporting

confidence: 74%

Macrophage environment turns otherwise MccJ25-resistant Salmonella into sensitive

et al. 2013

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“…We did not observe in our experiments an effect of the bacteriocins on Gram-negative bacteria. Most of the studies reporting the effective use of LABbacteriocins against Gram-negative bacteria are those in which bacteriocins were used in combination with treatments that permeate the outer membrane (Stevens et al, 1991;Vaara, 1992) or cause sub-lethal damage (Boziaris & Adams, 2001;Kalchayanand, Hanlin, & Ray, 1992). Combination of reuterin with any of the LAB-bacteriocins studied did not enhance the antimicrobial effect of reuterin on Gram-negative pathogens in milk in the present work.…”

Section: Discussionmentioning

confidence: 45%

Combined effect of reuterin and lactic acid bacteria bacteriocins on the inactivation of food-borne pathogens in milk

Arqués¹,

Rodríguez²,

Núñez³

et al. 2011

Food Control

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“…In this study heat stress increased the effectiveness of subtilosin against selected Gramnegative bacteria, similarly to that reported with nisin and Gramnegative bacteria. 9 This increased susceptibility could reduce the survival of these pathogens in the presence of subtilosin.…”

Section: Discussionmentioning

confidence: 99%

The spectrum of antimicrobial activity of the bacteriocin subtilosin A

Shelburne

An²,

Dholpe

et al. 2006

Journal of Antimicrobial Chemotherapy

180

118

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Background: Bacterocins are antimicrobial peptides produced by bacteria with a relatively narrow range of activity against closely related organisms. Subtilosin A is a bacteriocin produced by Bacillus subtilis that has activity against Listeria monocytogenes, which might indicate antimicrobial activity unusual for bacteriocins.Objectives: To examine the antimicrobial activity and factors affecting the activity of subtilosin A against a range of potentially pathogenic bacteria. Methods:The peptide was purified from cultures of B. subtilis and the MIC determined for 18 species of bacteria using a microdilution methodology. The extent of capsule formation was determined using microscopic examination of cells mounted in India ink. Protease mutants of a susceptible bacteria and mild heat shock were used to examine the effect of environmental stress on subtilosin A activity.Results: Subtilosin A proved to have antimicrobial activity against a wide range of bacteria including Gram-positive and Gram-negative bacteria and both aerobes and anaerobes. The peptide was less effective against capsulated forms of two Gram-negative bacteria than the non-capsulated strains of either. Heat shock but not protease activity also altered the effectiveness of the bacteriocin.Conclusions: Subtilosin A has limited antimicrobial activity against a number of human pathogens which, combined with its relative ineffectiveness against some capsulated pathogens, may limit its usefulness as a human therapeutic.

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Temperature shock, injury and transient sensitivity to nisin in Gram negatives

Cited by 50 publications

References 30 publications

Macrophage environment turns otherwise MccJ25-resistant Salmonella into sensitive

Macrophage environment turns otherwise MccJ25-resistant Salmonella into sensitive

Combined effect of reuterin and lactic acid bacteria bacteriocins on the inactivation of food-borne pathogens in milk

The spectrum of antimicrobial activity of the bacteriocin subtilosin A

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