Permeability of Gentamicin and Polymyxin B into the Inside of Bacillus subtilis Spores

Abstract

The penetration of gentamicin and polymyxin B into the inside of Bacillus subtilis spores was examined by an immunoelectron microscopy method with colloidalThe colloidal gold particles were located predominantly in the coat region of both gentamicin-treated and polymyxin Btreated spores and were hardly observed in the other regions, i.e., the cortex and core regions.When these antibiotic-treated spores were subsequently treated with CaCl2, the number of gold particles bound to the coat region was greatly decreased. These results suggest that these two antibiotics are able to penetrate into the spore coat but not into the cortex or core, that is, the primary permeability barrier to them exists between the coat and the cortex regions.

Characterization of the interaction of undomesticatedBacillus subtilis spores with Caco-2 cell line

“…According to the obtained results in the present study, the complete cell culture medium containing 400 μg/ml of gentamicin sulphate was determined as an efficient concentration relevant for the killing of all of the inoculated spores after 2.5 and 5 h in MBC assay. The probable mechanism of gentamicin entry into the B. subtilis spores, have previously been explained (Fujita et al, 1990). …”

Identification and Characterization of Sporulation-Dependent Promoters Upstream of the Enterotoxin Gene ( cpe ) of Clostridium perfringens

“…Similarly, only a few gold particles were seen with wild-type and cotS mutant spores in assays using preimmune serum (data not shown). To confirm the localization of CotS in wild-type spores, a statistical analysis of 20 photographs of wild-type and cotS mutant spores was carried out as described previously (15). The numbers of gold particles per 0.2 m 2 were clearly highest in the inner spore coat of the wild-type strain and were much higher than in the inner coats of cotS mutant spores (Fig.…”

Quantitative Analysis of Polymyxin B Released from Polymyxin B‐Treated Dormant Spores of Bacillus subtilis and Relationship between Its Permeability and Inhibitory Effect on Outgrowth

“…Most antibiotics also have little effect on spores, but we have previously demonstrated that cyclic polypeptide antibiotics such as polymyxin B and colistin, and aminoglycoside antibiotics such as streptomycin, kanamycin and gentamicin bind to the spores of Bacillus subtilis and inhibit them from growing after germination (12,13). And it was shown by immunoelectron microscopy that polymyxin B and gentamicin bound to the coat region, the outermost structure of a spore (6,15). Following treatment of polymyxin B-treated and gentamicin-treated spores with CaC12 dissociated these antibiotics from the spore coat (6) and reversed their inhibitory effect on growth (13).…”