D. Craig Wright

A novel surfactant nanoemulsion with broad-spectrum sporicidal activity against Bacillus species

Two nontoxic, antimicrobial nanoemulsions, BCTP and BCTP 401, have been developed. These emulsions are composed of detergents and oils in 80% water. BCTP diluted up to 1:1000 inactivated>90% of Bacillus anthracis spores in 4 h and was also sporicidal against three other Bacillus species. This sporicidal activity is due to disruption of the spore coat after initiation of germination without complete outgrowth. BCTP 401 diluted 1:1000 had greater activity than BCTP against Bacillus spores and had an onset of action of <30 min. Mixing BCTP or BCTP 401 with Bacillus cereus prior to subcutaneous injection in mice reduced the resulting skin lesion by 99%. Wound irrigation with BCTP 1 h after spore inoculation yielded a 98% reduction in skin lesion size, and mortality was reduced 3-fold. These nanoemulsion formulas are stable, easily dispersed, nonirritant, and nontoxic compared with other available sporicidal agents.

Bacitracin Inhibits the Oyster Pathogen Perkinsus marinus in Vitro and in Vivo

Abstract The in vitro growth rates of two isolates of Perkinsus marinus were significantly reduced by bacitracin. Upon coincubation with 1 mg bacitracin/mL, the doubling times rose from 27 ± 2.1 h to 34 ± 2.9 h for the LMTX-1 isolate (P < 0.001) and from 15 ± 1.9 h to 22.2 ± 2.4 h for the Perkinsus-1 isolate (P < 0.001). At 10 mg bacitracin/mL, viability of both isolates was much reduced (P < 0.0001). The sensitivity of P. marinus to bacitracin was examined in vivo in two clinical trials. In the first, individual eastern oysters Crassostrea virginica were injected with 107 Perkinsus-1 cells, then fed bacitracin at a concentration of 5 or 50 mg/mL encapsulated in lipid vesicles daily for 6 weeks. Parasite body burden was significantly reduced in oysters administered 5 mg bacitracin/mL (3.3 × 104 ± 2.5 × 104 hypnospores/g wet tissue) or 50 mg/mL (5.3 × 104 ± 6.4 × 104 hypnospores/g) as compared with control oysters (3.2 × 105 ± 4.7 × 105 hypnospores/g, P < 0.05) that received encapsulated seawater only. In ...