ABSTRACT
AIMS: To determine the production of bacteriocin by Shigella flexneri strains, to relate their production to the presence of dysenteric diarrhoea and to asses the genetic determination of the bacteriocin. METHODS AND RESULTS: One hundred and sixteen strains of Sh. flexneri were isolated from patients with diarrhoea and 49 of them produced bacteriocin active against several Escherichia coli and abacteriocinogenic Sh. flexneri strains. The extrachromosomal DNA isolated from bacteriocinogenic Sh. flexneri strains were used as a substrate to transform E. coli HB-101 cells by means of electroporation. CONCLUSIONS: Only the Sh. flexneri strains isolated from dysenteric diarrhoea produced bacteriocin. It was demonstrated that a plasmid of approx. 3 kb was responsible for the genetic determination of these anti-bacterial substances. SIGNIFICANCE AND IMPACT OF THE STUDY: A 3-kb plasmid that harboured information for the production of bacteriocin by Sh. flexneri strains was described. The production of this bacteriocin may be related to dysenteric diarrhoea produced by these bacterial strains.
Subject(s)
Anti-Bacterial Agents/metabolism , Bacteriocins/metabolism , Dysentery, Bacillary/microbiology , Escherichia coli/metabolism , Plasmids , Shigella flexneri/genetics , Shigella flexneri/metabolism , Adolescent , Adult , Anti-Bacterial Agents/pharmacology , Bacteriocins/genetics , Bacteriocins/pharmacology , Child , Child, Preschool , Humans , Middle Aged , Plasmids/chemistry , Recombinant Proteins/biosynthesis , Shigella flexneri/drug effects , Transformation, BacterialABSTRACT
OBJECTIVE: To analyse the antimicrobial activity of the peptide PsVP-10 against 67 resistant Enterococcus faecalis strains isolated from clinical samples. METHODS: The qualitative disc diffusion method and MIC determinations were used. RESULTS: The presence of several multidrug-resistant phenotypes of E. faecalis was demonstrated, in which there were high MICs to chloramphenicol, tetracycline, vancomycin, cefaloridine, ampicillin and gentamicin. In comparison, the peptide PsVP-10 showed lower MICs against all the multidrug-resistant and susceptible E. faecalis. CONCLUSIONS: There is an urgent need for the development of novel antimicrobial agents against the highly resistant E. faecalis. The present study shows that the peptide PsVP-10 might make a contribution to the solution of this serious problem.
