284 DIFGO MANUAL 



medium. At least 1 ml. of Bacto-Penase for each 50,000 units of penicillin to be 

 tested should be incorporated in 15 ml. of sterile Bacto-Fluid Thiogly collate 

 Medium under aseptic conditions. The medium containing Bacto-Penase must not 

 be heated. Most laboratories find it more convenient to use Bacto-Penase Con- 

 centrate for sterility testing. The sterility testing of penicillin products for yeasts 

 and molds is accomplished by adding the test samples to Bacto-Sabouraud Liquid 

 Medium and incubating for 5 days at room temperature. The sterility testing of 

 products for yeasts and molds which have high concentrations of penicillin may 

 require the addition of Bacto-Penase Concentrate to the medium. 



Bacto-Penase is stable when stored at refrigerator temperatures. At normal 

 room temperature slow deterioration of Bacto-Penase does occur, and for that 

 reason this product, or media prepared with it, should be stored at 2-6° C. 



Bacto-Penase is regularly supplied in packages of one-half dozen tubes of 20 

 ml. each. 



1 Science, loi :365: 1945. * Compilation of Regulations for Tests and 



2 Science, 102:355:1945. Methods of Assay and Certification of Anti- 



3 Diagnostic Procedures and Reagents, Third biotic Drugs, Federal Security Agency, Food 

 Edition: 55: 1950. and Drug Administration. 



BACTO-PENASE CONCENTRATE (B346) 



Bacto-Penase Concentrate is a highly potent sterile thermolabile biological ex- 

 tract possessing the capacity to neutralize the antibiotic properties of all known 

 types of penicillin. It is non-toxic to microorganisms and is therefore, particu- 

 larly satisfactory for use in the sterility testing of penicillin or products containing 

 penicillin, and in ascertaining the microbial counts on penicillin-containing prod- 

 ucts. Bacto-Penase Concentrate is recommended as a penicillinase for use in all 

 official procedures for the sterility testing of penicillin as specified under the 

 regulations promulgated by the U. S. Government.^ Bacto-Penase Concentrate 

 may be used in media for culturing organisms from blood and other body fluids 

 containing penicillin, and for estimation of penicillin levels in such fluids, but 

 for these purposes Bacto-Penase is recommended. 



One ml. of Bacto-Penase Concentrate will inactivate 500,000 units of penicillin, 

 as indicated by the following test procedures: 



Prepare dilutions of Bacto-Penase Concentrate of 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 

 1:8, 1:9 and 1 : 10 in sterile distilled water. Add 1 ml. of each dilution to a series 

 of test tubes containing 15 ml. of Bacto-Fluid Thioglycollate Medium. Add 1 ml. 

 of a solution of penicillin containing 50,000 units per ml. to each tube and allow 

 to remain at room temperature for two hours. Inoculate each tube with 1 ml. of 

 a 24-hour broth culture of Micrococcus pyogenes var. aureus P209 diluted 1 to 

 1000 and incubate at 35-37°C. for 24 hours. Determine the highest dilution 

 permitting growth in this period, and multiply this dilution of Bacto-Penase 

 Concentrate by 50,000. This will give the actual units of penicillin that Bacto- 

 Penase Concentrate will inactivate. 



The sterility of penicillin is determined by adding the test sample to sterile 

 Bacto-Fluid Thioglycollate Medium containing Bacto-Penase Concentrate and 

 incubating the tubes at 35-37°C. for 4 days. The test is performed in tubes con- 

 taining 15 ml. of medium. At least 1 ml. of Bacto-Penase Concentrate for each 

 500,000 units of penicillin to be tested should be incorporated in 15 ml. of sterile 

 Bacto-Fluid Thioglycollate Medium under aseptic conditions. The medium con- 

 taining Bacto-Penase Concentrate must not be heated. Bacto-Penase Concentrate 

 is recommended for testing the sterility of 50,000 units or larger amounts of peni- 

 cillin, while Bacto-Penase may be used for the sterility testing of smaller amounts 

 of penicillin. 



