Expression of ompR gene in the acid adaptation and thermal resistance of Salmonella Enteritidis SE86

  • Ana Carolina Ritter Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brasil
  • Donatella Bacciu Università Degli Studi di Sassari, Sassari, Sardegna, Italy
  • Lucelia Santi Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brasil
  • Salvatore Rubino Università Degli Studi di Sassari, Sassari, Sardegna, Italy
  • Sergio Uzzau Università Degli Studi di Sassari, Sassari, Sardegna, Italy
  • Eduardo Cesar Tondo Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brasil
Keywords: Salmonella Enteritidis, ompR, thermal resistance, acid adaptation

Abstract

Introduction: The objective of this study was to evaluate the involvement of the ompR gene in the acid adaptation and thermal resistance of S. Enteritidis SE86, responsible agent of more than 95 % of investigated food-borne diseases, throughout the last decade in Southern Brazil. In this study, we constructed a mutant strain of S. Enteritidis SE86 (ΔompR) that was attenuated by a knockout technique. The OmpR protein expression was determined in a tagged (3XFLAG) strain of S. Enteritidis SE86.

Methodology: The mutant strains were cultivated separately in nutrient broth and nutrient broth supplemented with 1% glucose (NBG) to induce acid adapted cells. The organisms were exposed to different temperature such as 37 ºC, 52 ºC, and 60ºC. The survival of the SE86 wild type (WT) and attenuated strain was determined by bacterial count, and the tagged protein (ompR::3XFLAG cat::FLAG) was detected by SDS-PAGE and immunoblotting with anti-FLAG antibodies.

Results: Results showed that when exposed at 52ºC, the acid-adapted SE86 WT cells were completely inactivated after 300 minutes; however, non-adapted cells (WT and ΔompR) and acid-adapted ΔompR demonstrated higher thermal sensitivity, since they were completely inactivated in 240 minutes. At 60ºC, the acid-adapted SE86 ΔompR also demonstrated higher sensitivity that SE86 WT, being totally inactivated after 15 minutes, while the WT cells were inactivated in 20 minutes.

Conclusion: The acid adapted cells showed increased expression of OmpR when exposed to 52 ºC and 60ºC, this confirmed the requirement of acid adaptation  for S. Enteritidis SE86 to resist elevated temperatures.

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Author Biographies

Donatella Bacciu, Università Degli Studi di Sassari, Sassari, Sardegna, Italy

Dipartamento di Scienze Biomediche

Salvatore Rubino, Università Degli Studi di Sassari, Sassari, Sardegna, Italy
Dipartamento di Schienze Biomediche
Sergio Uzzau, Università Degli Studi di Sassari, Sassari, Sardegna, Italy
Dipartamento di Schienze Biomediche
Eduardo Cesar Tondo, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brasil
Instituto de Ciência e Tecnologia de Alimentos- ICTA/UFRGS
Published
2014-04-15
How to Cite
1.
Ritter AC, Bacciu D, Santi L, Rubino S, Uzzau S, Tondo EC (2014) Expression of ompR gene in the acid adaptation and thermal resistance of Salmonella Enteritidis SE86. J Infect Dev Ctries 8:474-479. doi: 10.3855/jidc.3584
Section
Original Articles