Luis Jimenez and his colleagues at Immunomedics, Inc. have published a very comprehensive review of the validation of a growth-based rapid method as an alternative to the compendial sterility test. The full reference and abstract are provided below.
2012. Jimenez, L.; Rana, N.; Amalraj, J.; Walker, K.; Travers, K. Validation of the BacT/ALERT 3D System for Rapid Sterility Testing of Biopharmaceutical Samples. PDA Journal of Pharmaceutical Science and Technology. 66(1): 38.54.
The BacT/ALERT® 3D system was validated to determine the sterility of different types of biopharmaceutical samples such as water for injection, unprocessed bulk, and finished bulk. The installation, operation, and performance qualification were completed and verified under good manufacturing practices. During the installation and operation validation stages, the functionality and security of the system and software were completed and verified. For the performance qualification, 11 microorganisms were evaluated, six compendial (Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Candida albicans, Aspergillus niger, Clostridium sporogenes), one representing the number one microbial species in sterile product recalls (Burkholderia cepacia), and four environmental isolates (Kocuria rhizophila, Staphylococcus haemolyticus, Methylobacterium radiotolerans, and Penicillium spp.). Nine of the microorganisms were spiked into three different types of biopharmaceutical samples by three different analysts on different days to ascertain the equivalence, ruggedness, sensitivity, time of detection, and repeatability. In all samples, the BacT/ALERT® exhibited equivalent or better detection than the standard test. With the exception of M. radiotolerans, all 11 microorganisms were detected within 2.5 days using the BacT/ALERT® system and the standard test. The detection times for M. radiotolerans in the three sample types averaged 5.77 days. The minimum detectable level of cells for all the microorganisms tested was found to be within 1 to 2 CFU. The system optimized sterility testing by the simultaneous on-line, non-destructive incubation and detection of microbial growth.