212 MEDICAL BACTERIOLOGY 



Vaccines are sterilized by heat in a water bath at the minimum temperature 

 and time of exposure that will kill the organism. 



After heating, several loopsful of the vaccine are planted on culture media 

 and incubated to prove sterility. 



When the vaccine has been sterilized, o.io to 0.25 per cent, of tricresol is 

 added and the vaccine sealed in appropriate sterile containers. 



The most important vaccines made, according to the technique just de- 

 scribed, will be mentioned, also the media upon which they may be cultivated, 

 temperatures and time of exposure required to sterilize and purpose for which 

 they are employed: 



TYPHOID VACCINE 



All strains of the typhoid bacillus do not possess equal immunizing proper- 

 ties. One having proved immunizing power is used. It is planted on plain 

 agar. The bacterial suspension is sterilized in a water bath at 56C. to 6oC. for 

 J^ hour. 



Typhoid vaccine is used to produce immunity, to combat sequelae of typhoid 

 fever and sometimes in the treatment of typhoid fever. 



Dose. The average immunizing dosage consists of three injections at in- 

 tervals of 10 days; the first 500,000,000, second 1,000,000,000 and third 1,000,- 

 000,000 organisms. In the treatment of typhoid fever and sequelae the dose 

 varies from 500,000 to 1,000,000,000 at intervals between injections from 2 to 

 20 days. 



Vaccines of the various paratyphoid bacilli, the bacillus coli, the various 

 dysentery bacilli and the spirillum of cholera are made in the same way, have 

 the same dosage and are employed principally to immunize against infection 

 and in the treatment of sequelae, occasional and with less success in the treat- 

 ment of subacute or prolonged cases of these diseases. 



GONOCOCCUS VACCINE 



Gonococci are cultured on media composed of about 6 parts glycerin agar 

 and 4 parts of blood, blood serum, ascitic fluid, or egg. The vaccine is sterilized 

 in a water bath at 55C. to 6oC. for from 10 to 30 minutes. Gonococcus 

 vaccine does not confer immunity; it is sometimes of value in acute urethritis, 

 but seems most" effective in subacute and chronic infections and sequelae of 

 gonorrhoea. 



The average initial dose for children is 5,000,000, for adults 25,000,000. 

 Reactions are to be avoided. 



Meningococcus vaccine is made in the same way but is seldom used and 

 there is not much evidence in regard to its indications or value. 



STAPHYLOCOCCUS VACCINE 



When making a stock vaccine a polyvalent one should be made. If it is to 

 be a staphylococcus aureus vaccine, then pure cultures of staphylococcus aureus 

 should be obtained from as many different sources as possible from the blood 



