Previous studies have shown that pretreatment of E. coli with low doses of kanamycin have generated an increase in the resistance to high doses of kanamycin as well as induced cross resistance to a broad range of unrelated antibiotics, and that multiantibiotic-resistant E. coli had lower levels of OmpF porin. In this study, the role of OmpC and OmpF porins in the development of cross resistance...

A patient with Salmonella muenchen sepsis was unsuccessfully treated with ampicillin. During therapy, four strains that showed stepwise ampicillin resistance and affected other beta-lactams and unrelated antibiotics were isolated sequentially. Resistance was caused by decreased outer membrane permeability associated with diminished expression of porin OmpF. Furthermore, the most resistant isola...

Pathway I. Group A nuclease colicins parasitize and bind tightly (Kd ≤ 10(-9) M) to the vitamin B12 receptor on which they diffuse laterally in the OM (outer membrane) and use their long (≥100 Å; 1 Å=0.1 nm) receptor-binding domain as a 'fishing pole' to locate the OmpF porin channel for translocation. Crystal structures of OmpF imply that a disordered N-terminal segment of the colicin T-domain...

BACKGROUND Despite evidence that altered membrane porins may impair microbial drug uptake thereby potentially compounding efflux pump-mediated multidrug resistance, few studies have evaluated gene transcription to identify multidrug-resistance-associated porins and other potential drug targets. METHODS Genes that encode six membrane porins (fadL, lamB, ompC, ompF, ompW and yiaT) and two membr...