Isolation and characterization of Escherichia coli strains producing microcins of B and C types

Abstract

A screening of 11956 enterobacteria isolates resulted in selection of seven active microcin-producing strains. The microcins were shown to be peptides or their derivatives with a rather broad spectrum of activity, mainly against Gram-negative bacteria. According to cross-immunity criteria, the microcins studied belonged to two of the previously suggested types, B (five strains) and C (two strains). Those of type B could be further classified into two subtypes on the account of differences in the spectrum of antibacterial activity. In five cases out of seven the microcin-producing ability has been attributed to plasmids that the strains harboured. The effect of microcins on sensitive cells was shown to depend on ompR and ompF gene products.

Structural and Functional Diversity of Microcins, Gene-Encoded Antibacterial Peptides from Enterobacteria

“…MccC7/C51 is active against several genera and species of enterobacteria such as Escherichia , Klebsiella , Salmonella , Shigella, Yersinia and Proteus [66][67][68] . It inhibits the growth of E. coli strains at 100-500 n M .…”

Microcin C51 Plasmid Genes: Possible Source of Horizontal Gene Transfer

“…Microcin C51 (MccC51) belongs to the modified microcin class. It is a nucleotide-peptide antibiotic (1,178 Da) produced by a natural strain of Escherichia coli isolated in Moscow (Russia) from the feces of a healthy child (14). A recent reinvestigation of the MccC51 structure (3) showed that it differs from the previously published structure (18).…”

“…MccC51 exhibits a strong antibacterial activity, since it inhibits the growth of different E. coli strains when present at 0.1 to 0.5 g/ml. The spectrum of MccC51 activity includes various genera and species of Enterobacteriaceae such as Enterobacter, Citrobacter, Klebsiella, Salmonella, Shigella, and Yersinia (14,17). MccC51 inhibits protein synthesis (I.…”

Inhibition of Vibrio parahaemolyticus by a bacteriocin-like inhibitory substance (BLIS) produced by Vibrio mediterranei 1

“…Experiments carried out using proteolytic enzymes confirmed the proteinaceous nature of BLIS-400. Trypsin and a-chymotrypsin did not hydrolyse polypeptides in BLIS-400 preparation, probably due to the presence of enzyme inhibitors (Khmel et al 1993). On the contrary, gel electrophoresis indicated that proteinase K was able to degrade BLIS-400, although a residual antimicrobial activity remained after treatment, as reported by others (Risøen et al 2004;Kang and Lee 2005), suggesting partial digestion of the active compound, or production of free active peptide(s) able to kill the sensitive strain.…”