Staphylococcus aureus is a major food-borne pathogen due to the production of enterotoxin and is particularly prevalent in contaminated milk and dairy products. The lactic acid bacteria (LAB) are widely used as biocontrol agents in fermented foods which can inhibit pathogenic flora. In our work, we investigated the influence of three strains of LAB (Lactobacillus plantarum, Streptococcus thermophilus and Enterococcus durans) on the relative expression of three enterotoxin genes (sea, sec, sell) and eight virulence and/or regulatory genes (sarA, saeS, codY, srrA, rot, hld/RNAIII, agrA/RNAII, sigB) in two S. aureus strains (MW2 and Sa1612) in TSB and reduced-fat milk (1.5 %) at 30 °C over a 24-h period. The tested LAB and S. aureus strains proved to be mutually non-competitive or only slightly competitive during co-cultivation. In addition, under the above-mentioned conditions, differential gene expression between the S. aureus MW2 and Sa1612 strains was well documented. S. aureus growth was changed in mixed culture with LAB; however, its effect on the repression of sea and sec expression correlated with production of these virulence factors. In comparison, the presence of LAB strains generally inhibited the expression of sec, sell, sarA, seaS, agrA/RNAII and hld/RNAIII genes. The effect of LAB strains presence on the expression of sea, codY, srrA, rot and sigB genes was medium, time, LAB and S. aureus strain specific. SEA and SEC production was significantly reduced in milk compared to TSB in pure culture. After the 24-h cultivation, S. aureus MW2 and Sa1612 SEC production was 187 and 331 times lower in milk compared to TSB, respectively (0.07 and 0.39 ng/mL in milk, versus 13.1 and 129.2 ng/mL in TSB, respectively). At the same time S. aureus MW2 and Sa1612 SEA production was 77 and 68 times lower in milk compared to TSB, respectively (0.99 and 0.17 ng/mL in milk, versus 76.4 and 11.5 ng/mL in TSB, respectively). This study has revealed new insights into the interaction between S. aureus and LAB (L. plantarum, S. thermophilus, E. durans) on the level of the expression and/or production of S. aureus enterotoxins, regulatory and virulence genes in different media, including milk. This study provides data which may improve the quality of food production.

• Klíčová slova
• ELISA, RT-qPCR, SEA, SEC, Staphylococcus aureus, Virulence genes,
• MeSH
• Enterococcus fyziologie   MeSH
• enterotoxiny biosyntéza   genetika   MeSH
• faktory virulence genetika   MeSH
• kokultivační techniky MeSH
• kultivační média MeSH
• Lactobacillus plantarum fyziologie   MeSH
• mikrobiální interakce MeSH
• mléko * MeSH
• potravinářská mikrobiologie MeSH
• regulační geny MeSH
• Staphylococcus aureus genetika   růst a vývoj   metabolismus   patogenita   MeSH
• Streptococcus thermophilus fyziologie   MeSH
• transkriptom MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• enterotoxiny MeSH
• faktory virulence MeSH
• kultivační média MeSH

Exfoliative toxin A (ETA)-coding temperate bacteriophages are leading contributors to the toxic phenotype of impetigo strains of Staphylococcus aureus. Two distinct eta gene-positive bacteriophages isolated from S. aureus strains which recently caused massive outbreaks of pemphigus neonatorum in Czech maternity hospitals were characterized. The phages, designated ϕB166 and ϕB236, were able to transfer the eta gene into a prophageless S. aureus strain which afterwards converted into an ETA producer. Complete phage genome sequences were determined, and a comparative analysis of five designed genomic regions revealed major variances between them. They differed in the genome size, number of open reading frames, genome architecture, and virion protein patterns. Their high mutual sequence similarity was detected only in the terminal regions of the genome. When compared with the so far described eta phage genomes, noticeable differences were found. Thus, both phages represent two new lineages of as yet not characterized bacteriophages of the Siphoviridae family having impact on pathogenicity of impetigo strains of S. aureus.

• MeSH
• DNA virů chemie   genetika   MeSH
• DNA viry genetika   izolace a purifikace   MeSH
• epidemický výskyt choroby MeSH
• exfoliatiny genetika   MeSH
• fylogeneze MeSH
• genom virový * MeSH
• impetigo epidemiologie   mikrobiologie   MeSH
• infekce spojené se zdravotní péčí epidemiologie   MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• novorozenec MeSH
• otevřené čtecí rámce MeSH
• polymorfismus délky restrikčních fragmentů MeSH
• pořadí genů MeSH
• porodnice MeSH
• přenos genů horizontální MeSH
• profágy klasifikace   genetika   izolace a purifikace   MeSH
• sekvenční analýza DNA MeSH
• sekvenční homologie MeSH
• shluková analýza MeSH
• stafylokokové bakteriofágy klasifikace   genetika   izolace a purifikace   MeSH
• stafylokokové infekce epidemiologie   mikrobiologie   MeSH
• Staphylococcus aureus izolace a purifikace   virologie   MeSH
• syntenie MeSH
• transdukce genetická MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Názvy látek
• DNA virů MeSH
• exfoliatiny MeSH