Murray P R, Christman J L
J Antibiot (Tokyo). 1978 Dec;31(12):1296-8. doi: 10.7164/antibiotics.31.1296.
The stability of eight antimicrobial agents in WILKENS-CHALGREN broth was evaluated. The activities of only carbenicillin and benzyl penicillin were significantly decreased after storage for eight weeks at--20 degrees C. Anaerobic reduction of the susceptibility testing broth prior to inoculation was found to be unnecessary.