SENSITIVITY PROFILES OF ANTIMICROBIAL PEPTIDES PRODUCED BY LACTIC-ACID BACTERIA AGAINST REGIONAL S. AUREUS STRAINS ISOLATED FROM BOVINE MASTITIS

AGUIRRE GABRIELA; LORENZUTTI AUGUSTO MATÍAS; ZARAZAGA MARÍA DEL PILAR; CAPELLO INGRID; GRAMAGLIA ALDANA; LITTERIO NICOLÁS JAVIER

Mar del Plata

Congreso; XLVIII REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE FARMACOLOGÍA EXPERIMENTAL; 2016

Sociedad Argentina de Farmacología Experimental

􀀫n response to the gro􀁙ing development of bacterial resistanceto antimicrobial agents 􀀊AT􀀯􀀋, the use of antimicrobial p eptides􀀊A􀀲􀀋 produced by lactic􀀏acid bacteria 􀀊LA􀀤􀀋 could be an a lternative.There is limited evidence about antimicrobial efficacy ofA􀀲s against bacteria that cause bovine mastitis. The objective ofthis study 􀁙as to assess the antimicrobial activity of A􀀲s againstS. aureus strains isolated from bovine mastitis in Cordoba,Argentina. S. aureus (n􀀟􀀖􀀘􀀋 and LA􀀤 􀀊n􀀟􀀗􀀖􀀋 strains 􀁙ere isolatedfrom mil􀁍 samples. The antimicrobial activity of substances incell􀀏free extracts of LA􀀤 against S. aureus strains 􀁙as evaluatedby agar diffusion technique. After treatment 􀁙ith proteinase 􀀭,four A􀀲s 􀁙ere recovered, 􀁙hich 􀁙ere concentrated and purifiedby adsorption􀀏desorption, dialysis, lyophilization and S􀀦S􀀏􀀲A􀀩Eelectrophoresis. The A􀀲s concentrations 􀁙ere estimated by􀀫mage􀀬􀅠 soft􀁙are. The minimum inhibitory concentration 􀀊􀀯􀀫C􀀋for A􀀲s 􀀊􀀕 produced by Lactobacillus spp and􀀓 by Enterococcusspp) against S. aureus 􀁙ere determined. A􀀲s concentrationsobtained from purification 􀁙ere unable to reach 􀀯􀀫C􀀗􀀒 and MIC90against S. aureus, but MIC􀀕􀀗 􀁙ere calculated for all peptides. 􀀱nlyone of the A􀀲s 􀁙as identified by mass spectrometry, pendingthe results of the remaining. The amino acid sequence of theidentified peptide 􀀗􀀒S􀀏L􀀕􀀔, corresponds to ribosome􀀏constitutiveLactobacillus brevis. There 􀁙as no reports of its antimicrobialactivity, and its amino acidic content is characteristic of cationicA􀀲s of bacterial origin. A 􀀕􀀗.􀀖􀀔􀀇 inhibition of S. aureus strains􀁙as achieved only 􀁙ith a relative high concentration of thepeptide 􀀊􀀒.􀀓􀀓􀀗 􀁺g/ml􀀋. 􀀷nderstanding thestructure􀀏activity relationshipof A􀀲s is essential for development of ne􀁙 therapeuticantimicrobial alternatives.