Original scientific paper
https://doi.org/10.15567/mljekarstvo.2018.0102
Expression of toxic shock syndrome toxin-1 gene of Staphylococcus aureus in milk: Proof of concept
Milijana Babić
; Faculty of Veterinary Medicine, University of Belgrade, Bul. Oslobođenja 18, 11000 Belgrade, Serbia
Marija Pajić
; Faculty of Agriculture, University of Novi Sad, Trg Dositeja Obradovića 8, 21000 Novi Sad, Serbia
Aleksandra Nikolić
; Institute of Meat Hygiene and Technology, Kaćanskog 13, 11040 Belgrade, Serbia
Vlado Teodorović
; Faculty of Veterinary Medicine, University of Belgrade, Bul. Oslobođenja 18, 11000 Belgrade, Serbia
Milorad Mirilović
; Faculty of Veterinary Medicine, University of Belgrade, Bul. Oslobođenja 18, 11000 Belgrade, Serbia
Lazar Milojević
; Institute of Meat Hygiene and Technology, Kaćanskog 13, 11040 Belgrade, Serbia
Branko Velebit
orcid.org/0000-0002-7577-8074
Abstract
The aim of this study was to assess the expression of a toxic shock syndrome toxin-1 (TSST-1) gene of Staphylococcus aureus in different types of milk, depending on inadequate temperature and storage conditions. Pasteurized and UHT milk were inoculated with monotoxic TSST-1 strain of S. aureus and growth kinetics was determined by the drop plate method using Baird-Parker agar medium in accordance with EN ISO 6888-1. The patterns of gene regulation were detected by quantitative reverse transcriptase PCR. Relative quantification method for statistical significance testing was used to detect significant gene expression responses. The results of experiments showed the dependence of the growth rate and consequent up-regulation of TSST-1 encoding gene on storage time-temperature and type of milk. In contaminated pasteurized and UHT milk kept at both 15 °C and 22 °C S. aureus significantly increased its virulent potential over time. This effect was a bit more emphasized in UHT milk serving as a “proof of concept”. Possible explanation could be a presence of lactic acid bacteria in pasteurized milk which is known to have down-regulatory effect on TSST-1 gene. Maintenance of the milk storage temperature below 8 °C and employment of microbiological control measures in hygienic practices, from milk producer through retailer and on to the consumer is of utmost importance to decrease risk of non-emetic staphylococcal poisoning.
Keywords
S. aureus; toxic shock syndrome toxin-1; milk
Hrčak ID:
192295
URI
Publication date:
10.1.2018.
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