Detection of the sensitivity phage preparation Stafal and its ability to reduce biofilm formation of Staphylococcus aureus

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DVOŘÁČKOVÁ Milada RŮŽIČKA Filip DVOŘÁKOVÁ HEROLDOVÁ Monika

Rok publikování 2013
Druh Konferenční abstrakty
Citace
Popis In these days we find that the current antibiotics therapy fails in more and more cases, this due to bacterias getting resistant. One of the possible fields for investigation is an introduction of phage therapy. Phage therapy is applied on infections caused by S. aureus. Treatment of these infections may get complicated also by formation of bacterial biofilms. Objectives: The goal was to find out how the preparate interacts with planktonic forms of bacteria and bacteria growing in biofilms. Methods 271 strains of S. aureus from various clinical materials were tested for sensitivity to Stafal by bilayer agar method, we as well tested biofilm production according Stepanovic method using microplates for tissue culture. 25 strains with the greatest biofilm formation were afterwards separately tested on the effectiveness of Stafal on the biofilm. Biofilm was grown in microtitre plates, planktonic forms were removed, the wells were pipetting Stafal with phages at a concentration of 10E+9, 10E+8, 10E+7 10E+6 10E+5 PFU/ml and distilled water. Biofilm was detected by Stepanovic after 24-hour cultivation. In these strains, after cultivation with different dilution of Stafal we detected life planktonic bakteria by inoculating them on blood agar and enzymatic activity of biofilm using resazorin. Results: 99% of the tested strains were sensitive to the Stafal. Out of the 271 strains 219 showed strong, 31 moderate and 10 weak biofilm production and 11 without producing biofilm. MRSA strains according to the measured OD showed higher biofilm formation oOD 1.95 and MSSA were oOD 1.41. By using Stepanovic method, we have proved a statistically signifficant biofilm reduction. On the 25 chosen strains we have found out that concentration needed to interact with the planktonic forms of stafylococs reaches 10E+9, 10E+8 a 10E+7 PFU/ml, however some strains growing in the biofilm survives concentrations 10 to 100 higher, which was indicated by enzymatic activity. Conclusion: Our experiments indicate that the Stafal’s sensitivity to S.aureus is very high 269 sensitive strains (99%), moreover it is also fully sensitive to MRSA 95 strains (100%). It turned out, however, that preparation works perfectly on planktonic forms of staphylococci and less efficient on bacterias growing in biofilms.
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