Catalase and enumeration of stressed Staphylococcus aureus cells.

The effects of catalase on the enumeration of stressed (heated, reduced water activity, or freeze-dried) Staphylococcus aureus cells on several selective media were examined. The addition of catalase greatly increased the enumeration of stressed cells. The beneficial effects of catalase were most pronounced on those media least efficient in enumeration of stressed staphylococci, showing increases in enumeration of up to 1,100-fold.

Gentle lysis of Staphylococcus aureus at low temperature.

A low-temperature lysis procedure for Staphylococcus aureus is described. It is simple and requires no special equipment.

The surgical correction of the non-Caucasian nose.

Repairing the non-Caucasian nose can be satisfying to both patient and surgeon. Goals should be directed towards restoring balance and accent--not the elimination of racial characteristics. Careful technique, adhering to a group of principles, leads to exciting results with minimal morbidity and complications.

Catalase: its effect on microbial enumeration.

The addition of catalase to the surface of selective medium plates permitted increased enumeration of physically or chemically injured (stressed) microorganisms. Catalase acted by preventing the accumulation of hydrogen peroxide in, or around, injured cells. Heat-injured Staphylococcus aureus cells had decreased catalase activity, and heat-inactivated catalase had no effect on enumeration.

Spore membrane(s) as the site of damage within heated Clostridium perfringens spores.

Clostridium perfringens spores were injured by ultrahigh-temperature treatment at 105 C for 5 min. Injury was manifested as an increased sensitivity to polymyxin and neomycin. Since many of the survivors could not germinate normally the ultrahigh-temperature-treated spores were sensitized to and germinated by lysozyme.

Repair of heat-injured Clostridium perfringens spores during outgrowth.

Clostridium perfringens strain NCTC 8798 spores were injured by ultrahigh temperature treatment and were unable to outgrow in the presence of antibiotics used in selective enumeration media. Injured spores underwent repair in a nonselective laboratory medium and in foods.