The phototoxic inhibitory effect and phototoxic killing effect of micro-organisms

The toxic and phototoxic growth inhibitory and killing effect of Staphylococcus aureus, S. epidermidis, Escherichia coli, Pseudomonas aeruginosa, Streptococcus pyogenus gr. A, St. viridans, Pityrosporum ovale and Candida albicans were studied. P. ovale and St. viridans were the only micro-organisms with any toxic effect against the other micro-organisms tested. P. ovale inhibited the growth of S. aureus, S. epidermidis, Ps. aeruginosa and E. coli. St. viridans inhibited the growth of S. aureus, S. epidermidis, Ps. aeruginosa, E. coli, St. pyogenus gr. A and P. ovale. This effect was only growth inhibitory and not direct killing. The activity was increased by UVA on S. aureus, S. epidermidis and Ps. aeruginosa but not on E. coli and St. pyogenes gr. A. These effects of P. ovale and St. viridans may be of importance in the defense against infections.