Study of the determination of minimum inhibitory concentration of the mucus of Achatina fulica on Staphylococcus aureus ATCC 25923

Author(s)

Paula Adriane Piccolo Pieruzzi

• Document type: Master's Dissertation
• Press: Pirassununga.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2012-11-30

Examining board members

Maria de Fátima Martins; Marcos Veiga dos Santos; Arlindo Saran Netto

• Advisor: Maria de Fátima Martins

Abstract

The bovine mastitis is highly prevalent in dairy herds and antibiotic therapy is the procedure most commonly used to treat it. Staphylococcus aureus is the most frequently isolated etiologic agent in cases of mastitis and it has been shown in several studies the pattern of increasing antimicrobial resistance. Due to the development of resistant bacterias and the presence of antimicrobial residues in the milk the development of new treatments to solve those problems are required. The mucus of the molluscs Achatina fulica contains a glycoprotein called achacin that presents antimicrobial activity against Gram positive bacteria. The aim of this study was the evaluation of the in vitro antimicrobial activity of the A. fulica mucus of on S. aureus, as well the determination of the minimum inhibitory concentration (MIC) of A. fulica mucus purified on S. aureus ATCC 25923 and isolates of S. aureus from bovine intramammary infections. The mucus was purified by high performance liquid chromatography. The protein content in portion presenting the was quantified and microdiluted. The MIC determined for the purified mucus strain ATCC 25923 was 50 µg/mL and for the isolates of S. aureus ranged between 12,5 and 100 µg/mL. Among these samples, two isolates (6,7 %) showed MIC of 12,5 µg/mL, three (10 %) of MIC 25 µg/mL, twenty-three (76,6 %) MIC of 50 µg/mL and two (6,7 %) had an MIC of 100 µg/mL. The MIC50 for isolates was 50 µg/mL and MIC90 to100 µg/mL. It was found that the purified mucus showed bactericidal activity. The results showed in the present work improved the understanding and optimization of the biopharmaceutical microbiological potential that could be applied in new protocols in future veterinary therapy for the control of intramammary infections caused by S. aureus. (AU)

• FAPESP's process: 11/03794-2 - Study of determination of minimum inhibitory concentration of the mucus of Achatina sp on Staphylococcus aureus ATCC 29213
• Grantee: Paula Adriane Piccolo Pieruzzi
• Support Opportunities: Scholarships in Brazil - Master