Advanced

Acetic acid increases the phage-encoded enterotoxin A expression in Staphylococcus aureus

Wallin-Carlquist, Nina LU ; Cao, Rong LU ; Marta, Dora; da Silva, Ayla Sant'Ana; Schelin, Jenny LU and Radstrom, Peter LU (2010) In BMC Microbiology 10.
Abstract
Background: The effects of acetic acid, a common food preservative, on the bacteriophage-encoded enterotoxin A (SEA) expression and production in Staphylococcus aureus was investigated in pH-controlled batch cultures carried out at pH 7.0, 6.5, 6.0, 5.5, 5.0, and 4.5. Also, genomic analysis of S. aureus strains carrying sea was performed to map differences within the gene and in the temperate phage carrying sea. Results: The sea expression profile was similar from pH 7.0 to 5.5, with the relative expression peaking in the transition between exponential and stationary growth phase and falling during stationary phase. The levels of sea mRNA were below the detection limit at pH 5.0 and 4.5, confirmed by very low SEA levels at these pH values.... (More)
Background: The effects of acetic acid, a common food preservative, on the bacteriophage-encoded enterotoxin A (SEA) expression and production in Staphylococcus aureus was investigated in pH-controlled batch cultures carried out at pH 7.0, 6.5, 6.0, 5.5, 5.0, and 4.5. Also, genomic analysis of S. aureus strains carrying sea was performed to map differences within the gene and in the temperate phage carrying sea. Results: The sea expression profile was similar from pH 7.0 to 5.5, with the relative expression peaking in the transition between exponential and stationary growth phase and falling during stationary phase. The levels of sea mRNA were below the detection limit at pH 5.0 and 4.5, confirmed by very low SEA levels at these pH values. The level of relative sea expression at pH 6.0 and 5.5 were nine and four times higher, respectively, in the transitional phase than in the exponential growth phase, compared to pH 7.0 and pH 6.5, where only a slight increase in relative expression in the transitional phase was observed. Furthermore, the increase in sea expression levels at pH 6.0 and 5.5 were observed to be linked to increased intracellular sea gene copy numbers and extracellular sea-containing phage copy numbers. The extracellular SEA levels increased over time, with highest levels produced at pH 6.0 in the four growth phases investigated. Using mitomycin C, it was verified that SEA was at least partially produced as a consequence of prophage induction of the sea-phage in the three S. aureus strains tested. Finally, genetic analysis of six S. aureus strains carrying the sea gene showed specific sea phage-groups and two versions of the sea gene that may explain the different sea expression and production levels observed in this study. Conclusions: Our findings suggest that the increased sea expression in S. aureus caused by acetic acid induced the sea-encoding prophage, linking SEA production to the lifecycle of the phage. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
BMC Microbiology
volume
10
publisher
BioMed Central
external identifiers
  • wos:000279927800002
  • scopus:77952361176
ISSN
1471-2180
DOI
10.1186/1471-2180-10-147
language
English
LU publication?
yes
id
7cea185f-b423-4c76-9f22-451e8974e1a6 (old id 1657618)
date added to LUP
2010-08-23 14:37:10
date last changed
2018-06-11 13:10:04
@article{7cea185f-b423-4c76-9f22-451e8974e1a6,
  abstract     = {Background: The effects of acetic acid, a common food preservative, on the bacteriophage-encoded enterotoxin A (SEA) expression and production in Staphylococcus aureus was investigated in pH-controlled batch cultures carried out at pH 7.0, 6.5, 6.0, 5.5, 5.0, and 4.5. Also, genomic analysis of S. aureus strains carrying sea was performed to map differences within the gene and in the temperate phage carrying sea. Results: The sea expression profile was similar from pH 7.0 to 5.5, with the relative expression peaking in the transition between exponential and stationary growth phase and falling during stationary phase. The levels of sea mRNA were below the detection limit at pH 5.0 and 4.5, confirmed by very low SEA levels at these pH values. The level of relative sea expression at pH 6.0 and 5.5 were nine and four times higher, respectively, in the transitional phase than in the exponential growth phase, compared to pH 7.0 and pH 6.5, where only a slight increase in relative expression in the transitional phase was observed. Furthermore, the increase in sea expression levels at pH 6.0 and 5.5 were observed to be linked to increased intracellular sea gene copy numbers and extracellular sea-containing phage copy numbers. The extracellular SEA levels increased over time, with highest levels produced at pH 6.0 in the four growth phases investigated. Using mitomycin C, it was verified that SEA was at least partially produced as a consequence of prophage induction of the sea-phage in the three S. aureus strains tested. Finally, genetic analysis of six S. aureus strains carrying the sea gene showed specific sea phage-groups and two versions of the sea gene that may explain the different sea expression and production levels observed in this study. Conclusions: Our findings suggest that the increased sea expression in S. aureus caused by acetic acid induced the sea-encoding prophage, linking SEA production to the lifecycle of the phage.},
  articleno    = {147},
  author       = {Wallin-Carlquist, Nina and Cao, Rong and Marta, Dora and da Silva, Ayla Sant'Ana and Schelin, Jenny and Radstrom, Peter},
  issn         = {1471-2180},
  language     = {eng},
  publisher    = {BioMed Central},
  series       = {BMC Microbiology},
  title        = {Acetic acid increases the phage-encoded enterotoxin A expression in Staphylococcus aureus},
  url          = {http://dx.doi.org/10.1186/1471-2180-10-147},
  volume       = {10},
  year         = {2010},
}