ACTIVIDAD DEL PEPTIDO ANTIMICROBIANO MccJ25 EN MATRICES BIOLOGICAS

LÓPEZ, F.E; ZENOFF, A.M; SALOMÓN, R.A; FARIAS, R.N

Puerto Iguazú - Misiones

Congreso; SAIB 2004; 2004

Sociedad Argentina de Investigaciones Bioquimicas

  MccJ25 is a plasmid-encoded antibiotic consisting of 21 amino acid residues. MccJ25 has extreme resistance to heat, denaturing agents and proteases. The latter property led us to predict that it could survive in vivo proteolytic activity. To test this hypothesis, MccJ25 antimicrobial activity after incubation in different biomatrices and LB medium (as a control) was compared. No significant difference was found between the activity of biomatrix-treated MccJ25 and that of the control after 24-h incubation at 37ºC.  MccJ25 (0.1 mM) exerted potent antimicrobial activity on Salmonella newport when co-incubated with blood and blood fractions, since viable cell counts drop from 106 CFU/ml to 104 CFU/ml after 2 h incubation at 37ºC. When the same concentration of MccJ25 incubated in LB with an inoculum of 106 cells, the mean final viable count was 103 cells. For comparison, the antimicrobial activity of 1 mM MccJ25, which gave complete killing of S. newport in biomatrices, was greater than that of  ampicillin and rifampicin at the same concentration. Incubation with biomatrices alone caused no significant reduction in S. newport viability. We conclude that MccJ25 retains antimicrobial efficacy in complex biomatrices, including whole blood, plasma and serum. The present results are useful to establish conditions for an animal infection model in which to study in vivo the therapeutic action of MccJ25.10