A comparison of the MicroCount Digital System to plate count and membrane filtration methods for the enumeration of microorganisms in water for pharmaceutical purposes.

摘要

The enumeration of microorganisms in water for pharmaceutical purposes using the MicroCount Digital System (Millipore Corporation, Bedford, MA) was compared to the USP-recommended Pour Plate and Membrane Filtration Count methods. A study, using a pure culture of Buckholderia cepacia, ATCC#25416, showed that the accuracy, precision, reproducibility and linearity of the MicroCount ATP Bioluminescence System was equivalent to or better than the traditional methods. When the MicroCount System was used to monitor purified water and water for injection taps in a pharmaceutical plant over a month, comparable counts to the traditional methods were obtained within 24 hours compared to 48 to 72 hours with the other methods. The effectiveness of the memory device used for the isolation of colonies for characterization was demonstrated by comparing the number and pattern of the positive wells in the MicroCount plates with the isolation of colonies on the microbial count agar plates. The recovery on agar plates, although slightly higher, was not statistically different to the MicroCount plates. The predominated microorganisms isolated using all three methods were Ralstonia pickettii, Bacillus sphaericus, Stenotrophomonas maltophia, and a Staphylococcus species.