122 DIFGO MANUAL 



BACTO 



G G MEDIUM BASE (B289) 



DEHYDRATED 



Proteose Peptone No. 3, Difco 15 g. 



Corn Starch 1 g. 



Dipotassium Phosphate 4 g. 



Monopotassium Phosphate 1 g. 



Sodium Chloride 5 g. 



Bacto-Agar 10 g. 



Bacto-G C Medium Base, enriched with Bacto-Hemoglobin and Bacto-Supple- 

 ment A or Bacto-Supplement B, is recommended as a 24 hour culture medium 

 for the cultural diagnosis of gonorrhoea from acute and chronic cases in the 

 male and female. This medium has the advantage of requiring a shorter incu- 

 bation period than the medium prepared with Bacto-Proteose No. 3 Agar. 



In a survey^ under carefully controlled conditions twelve media recommended 

 for the isolation of the gonococcus were compared. Bacto-G C Medium Base 

 enriched with Bacto-Hemoglobin and Bacto-Supplement A or Bacto-Supplement 

 B was as effective in the number of gonococci cultures isolated as was any of the 

 media. In Diagnostic Procedures and Reagents- a medium prepared with Bacto-G 

 C Medium Base enriched with Bacto-Hemoglobin and Bacto-Supplement B pos- 

 sessed several advantages over the other media described for the isolation of the 

 gonococcus. It was pointed out that this medium is always immediately avail- 

 able and can be prepared in either large or small quantities, insuring a supply 

 of fresh moist medium essential for dependable results. This medium needs only 

 an incubation period of 24 hours instead of 48 hours usually required by other 

 media. 



Johnston^ described a medium for culturally detecting Neisseria gonorrhoeae 

 in exudates within 24 hours. The medium employed was a Chocolate Agar pre- 

 pared from Bacto-Proteose No. 3 Agar and Bacto-Hemoglobin to which was 

 added 30 per cent ascitic fluid and 1:50,000 tyrothricin. Inoculated plates of 

 this medium incubated in a partial carbon dioxide atmosphere in closed con- 

 tainers at 37 °C. for 24 hours yielded more positives than did the same medium 

 incubated for 48 hours. 



Attempts to elucidate the cause for the accelerated early growth response on 

 Johnston's modified medium over that of the regular enriched Chocolate Agar 

 indicated that the variation in growth rates on the two media was due prin- 

 cipally to the difference in solidity of the media. As a result of this observation 

 a new medium, Bacto-G C Medium Base, was designed for use as a 24 hour 

 medium in the laboratory diagnosis of gonococcal infections. 



In the examination of over 500 clinical specimens Christensen and Schoen- 

 lein* found the Bacto-G G Medium Base enriched with Bacto-Hemoglobin and 

 Bacto-Supplement A or Bacto-Supplement B to give equally as good or better 

 results after 24 hour incubation as did the Chocolate Agar prepared from Bacto- 

 Proteose No. 3 Agar, Bacto-Hemoglobin and Bacto-Supplement A or Bacto-Sup- 

 plement B incubated for similar or longer periods. Johnston^ compared Bacto-G 

 G Medium Base enriched with Bacto-Hemoglobin and Bacto-Supplement A or 

 Bacto-Supplement B with the medium containing ascitic fluid and tyrothricin 

 which she described and found their effectiveness to be comparable. Johnston 

 preferred the use of Supplement A as an enrichment since the crystal violet 

 helped in suppressing extraneous contaminating organisms. McRoy and Sala- 

 chow® of the Detroit Venereal Disease Clinics also reported excellent results 

 with Bacto-G G Medium Base enriched with Bacto-Hemoglobin and Bacto- 

 Supplement A and incubating for only 24 hours. Garpenteri'"^ in his report on a 



