Microcin PDI Inhibits Antibiotic-Resistant Strains of Escherichia coli and Shigella Through a Mechanism of Membrane Disruption and Protection by Homotrimer Self-Immunity.

Microcin PDI Inhibits Antibiotic-Resistant Strains of Escherichia coli and Shigella Through a Mechanism of Membrane Disruption and Protection by Homotrimer Self-Immunity. Appl Environ Microbiol. 2019 Mar 22;: Authors: Lu SY, Graça T, Avillan JJ, Zhao Z, Call DR Abstract Microcin PDI (MccPDI), a class IIa microcin that is produced by Escherichia coli strains 25 and 284, is known to inhibit foodborne pathogenic enterohemorrhagic E. coli (EHEC) serotypes O157:H7 and O26. Herein we demonstrate that MccPDI can inhibit Shigella strains and E. coli isolates that are multidrug resistant, the latter including strains known to cause urinary tract infections in people and companion animals. Two exceptions out of 17 strains were identified. One of the two resistant E. coli isolates (AR0349) has a mutation in a critical amino acid residue that was identified in prior work as requisite for the MccPDI precursor protein (McpM) to interact with the outer membrane porin F (OmpF) on susceptible cells. The second resistant E. coli strain (MAD 96) had no mutations in ompF, but it was PCR positive for two antimicrobial peptides of which colicin Ia/Ib likely inhibits the MccPDI-producing strain during co-culture. Recombinant McpM was still effective against strain MAD 96. To assess how MccPDI affects susceptible strains, results from both an extracellular ATP assay and a nucleic acid staining assay were consistent with membrane damage while addition of 20...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research