Identification and prevention of Staphylococcus aureus-caused infections may benefit from a fast and dependable method to distinguish between the methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) S. aureus strains. The current methods involving polymerase chain reaction and/or other molecular tests are usually laborious and time-consuming. We describe here a fast and low-cost method employing capillary zone electrophoresis (CZE) to distinguish between MRSA and MSSA. The method makes use of a supercritical water-treated fused silica capillary, the inner surface of which has subsequently been modified with (3-glycidyloxypropyl)trimethoxysilane. With optimized proportions of suitable additives to the background electrolyte, a CZE separation of MRSA from MSSA may be completed within 12 min. The cells were baseline-resolved, and resolution was determined to be 3.61. The isoelectric points of MSSA and MRSA were found to be the same for both groups of these strains, pI = 3.4.
Spores of the insect pathogen Bacillus popilliae Dutky have been formed in vitro from vegetative cultures. The procedure results reproducibly in 0.1 to 0.3% spore formation in cells of colonies grown on a solid medium under strictly denned conditions. Sporulation requires a selected strain of the organism, NRRL B-2309S, a relatively large and specific concentration of certain yeast extracts, a specific type of agar, the complete absence of glucose, the presence of acetate, and a pH within the range 7.2 to 7.5. Spore formation occurs slowly during 2- to 4-week incubation periods in surface colonies present in limited numbers on agar plates. Some of the spores formed in this manner survive heating for 15 minutes at 80 °C, and vegetative cultures derived from such spores are pathogenic via injection for larvae of the Japanese beetle, Popillia japonica Newman.
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