Sensitivity of Sublethally Injured Gram‐negative Bacteria to Pediocin P

Abstract

All Gram‐negative bacteria tested were normally resistant to the bactericidal action of pediocin P of Pediococcus pentosaceous Pep1, which had been isolated from vacuum‐packaged sausages. However, when they were subjected to sublethal stress (exposure to physical and chemical stresses such as freezing, heating and acid treatment) and were treated with pediocin P, gram‐negative bacterial cells that were normally resistant to pediocin P developed sensitivity to it and pediocin P reduced the viability of bacterial cells surviving sublethal stresses, although the extent of reduction varied with strain and type of treatment. When the combined effect of ethylenediaminetetraacetic acid (EDTA), sublethal heat and pediocin P was studied by adding EDTA and pediocin P to cell suspensions right before heating them, there was a considerable reduction in the number of viable cells, even at the lowest concentration of pediocin P tested. The results of our preliminary studies showed that sublethal injury can make the gram‐negative bacterial cells sensitive to pediocin P.

EFFECT OF PEDIOCIN DT10 ON LEUCONOSTOC MESENTEROIDES OZ‐N3 CELLS

“…1. However, pediocin DT10 was not effective in killing Gram‐negative bacteria unless they are sublethally injured (Osmanagaoglu 2005; our unpublished data).…”

“…1. However, pediocin DT10 was not effective in killing Gram-negative bacteria unless they are sublethally injured (Osmanagaoglu 2005;our unpublished data). Changes in viable counts of L. mesenteroides OZ-N3 during incubation at 30C in TGE broth containing different concentrations of pediocin DT10 were assessed (Fig.…”

Inhibitory effect of enterocin KP in combination with sublethal factors on Escherichia coli O157:H7 or Salmonella Typhimurium in BHI broth and UHT milk

“…The enhanced effect of chelators such as EDTA, disodium pyrophosphate, trisodium phosphate, hexametaphosphate, or citrate against gram-negative bacteria has been demonstrated for nisin both under laboratory conditions and in foods (Stevens et al, 1991;Siragusa, 1995a, 1995b;Carneiro De Melo et al, 1998;Boziaris and Adams, 1999;Fang and Tsai, 2003). Brochrocin C, enterocin AS-48, pediocin P, cerein 8A, carnocyclin A, and carnobacteriocin BM1 also showed an increased antimicrobial activity on EDTA or STTP-treated gram-negative bacteria (Abriouel et al, 1998;Gao et al, 1999; Ananou et al, 2005;Osmanağaoğlu, 2005;Lappe et al, 2009;Martin-Visscher et al, 2011). Application of enterocin KP together with sublethal heating caused the cell reduction of E. coli O157:H7 or S. Typhimurium by 3.39 and 3.64 log cycles, respectively.…”

“…These changes can cause sensitivity to hydrophobic compounds, efflux of periplasmic enzymes, and small molecules (Ter steeg et al, 1999;Boziaris and Adams, 2000;Cao-Hoang et al, 2008). The enhanced effect of cold shock and bacteriocins against gram-negative bacteria such as Aeromonas hydrophila, S. Typhimurium, Yersinia enterocolitica, E. coli 0157:H7, and Pseudomonas fluorescens has been demonstrated for nisin and pediocin AcH (Kalchayanand et al, 1992;Boziaris and Adams, 2000;Boziaris and Adams, 2001) and pediocin P (Osmanağaoğlu, 2005). Cao-Hoang et al (2008) reported that the combining effect of rapid chilling and nisin application caused a dose-dependent reduction in the population of E. coli cells in both exponential and stationary growth phases.…”

“…Our data are in accord with earlier findings that organic acids can sensitize gramnegative bacteria to bacteriocins by causing sublethal injury. Therefore, bacteriocins became active against gram-negative bacteria when used together with organic acids (Kalchayanand et al, 1992;Alakomi et al, 2000;Helander and Mattila-Sandholm, 2000;Osmanağaoğlu, 2005;Ananou et al, 2007).…”