Antibiotic activities of a Pseudomonas aeruginosa supernatant

OROSCO, FRANCISCO; ADLER CONRADO; VINCENT PAULA

Villa Carlos Paz - Córdoba

Congreso; 44th anual meeting. Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.

An antibiotic producing strain was isolated from a human sample. Genus and speciation determination were carried out by 16SrDNA and gyrB sequencing and subsequent analysis of the sequences using BLAST. The strain was identified as Pseudomonas aeruginosa. The supernatant showed against different human and plant pathogens. The antimicrobial substance diffused through a dialysis membrane with a 12kDa cut off. The antibiotic activity in the supernatant was resistant to all proteases tested. The activity partially decreased after exposing the culture supernatant to 121 C for 30 minutes. When the supernatant was adsorbed on a C8 cartridge two different fractions, with antibiotic activity, were eluted at methanol/water (40:60) and methanol/water(80:20). The two fractions show dissimilar action spectra. The 40% fractionwas susceptible to high temperature whereas the 80% fraction was totally resistant. These last results indicated that the supernatant of this strain contains at least two different antibiotics. An E.coli strain mutant in tolC gene was hiper-susceptible to the two fractions suggesting a posssible role of TolC protein in the exportation of these antibiotics. Identification and characterization of this compound produced by Pseudomonas aeruginosa may represent a novel antibiotic discovery