Pathogenic Bacteria 333 



plicated in localized infections. The aureus species appears to be 

 the more virulent of the two, although albus species have been 

 known to cause serious infections and food poisonings. A number 

 of toxins and metabolic products are produced by these bacteria in- 

 cluding a LETHAL TOXIN, a SKIN-DESTROYING TOXIN, LEUCOCIDIN 



(white cell-destroying poison), hemolysin, and coagulase. Some 

 strains produce an enterotoxin which causes food poisoning 

 symptoms when it acts in the intestines. This latter toxin is 

 thermostable and resists boiling for extended periods of time. 

 Although man is the most susceptible animal, enterotoxins can 

 affect monkeys and young kittens. Cramps, vomiting, diarrhea, 

 pain, and prostration are the usual symptoms of food poisoning, 

 but the mortality rate is practically nil. 



Unfortunately, food that is contaminated with micrococci does 

 not usually exhibit signs of spoilage, and the preformed toxins 

 are able to cause food poisoning symptoms in from three to twelve 

 hours after ingestion. Custards, cream-filled pastries, potato salad, 

 gravy, poultry dressing, and meats are the usual foods implicated 

 in such outbreaks of staphylococcus poisoning. 



Micrococci are more resistant to heating than are most other 

 non spore-forming bacteria. Ten minutes boiling will usually kill 

 these bacteria, but some strains have been found to withstand 

 80° C. for thirty minutes. 



Although some pathogenic micrococci produce coagulase which 

 might conceivably aid in localizing skin infections caused by these 

 bacteria, other factors are probably more important in this localiza- 

 tion response. There is evidence that metabolic products of the 

 micrococci attract large numbers of leucocytes to the area, and 

 the white blood cells wall off the focus of infection before it has an 

 opportunity to become generalized, pimples, boils (furuncles), 

 carbuncles, cystitis (bladder infection), pyelitis (kidney in- 

 fection), OSTEOMYELITIS ( boue infcctiou), puerperal fever, 

 sinusitis, MASTITIS (mammary gland infection), and septicemia all 

 may have a micrococcus etiology. 



The noxious agents produced by micrococci have been sug- 

 gested as possible agents for dissemination in public drinking water 



