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PDA Journal Paper Describes Identification Strategy Following Rapid Method Sterility Test Positive

In the May/June issue of the PDA Journal of Pharmaceutical Science and Technology, Jennifer Gray and colleagues describe a unique strategy for obtaining microbial identifications from positive sterility tests when using the Milliflex Rapid system. The full reference and abstract are provided below.

Identification of Micro-Organisms after Milliflex Rapid Detection—A Possibility To Identify Nonsterile Findings in the Milliflex Rapid Sterility Test. JENNIFER C. GRAY, DIETER MORANDELL, GUNTHER GAPP, NATHALIE LE GOFF, GUNTHER NEUHAUS, and ALEXANDRA STAERK. PDA J Pharm Sci and Tech 2011, 65 42-54.


The Milliflex Rapid System is used as a rapid microbiological method based on adenosine triphosphate (ATP) bioluminescence in the pharmaceutical industry to quantify the amount of micro-organisms present in water and in bioburden samples. The system can also be used for qualitative analyses, for example, to perform a rapid sterility test. This rapid sterility test has been successfully validated and implemented at Novartis and Sandoz. As the reagents used for the ATP bioluminescence reaction, which are directly sprayed on a micro-colony, disrupt the walls/membranes of the present cells to release ATP and therefore no intact cells for subsequent identification were believed to be present, the identification was supposed to be impossible until now.

During development and validation of a rapid sterility test with the Milliflex Rapid System, a possibility to identify contaminants was found. A method based on regrowth of the Milliflex Rapid-treated microbial cells and consecutive 
genotypic identification reproduced feasible and robust results. The data presented here show that sufficient recovery of the micro-colonies detected with the Milliflex Rapid System was reached with the test strains, except with 
Penicillium spec. The chosen micro-organisms represent the full spectrum of environmental isolates and ATCC strains, and it was shown that they are not destroyed after application of the reagents for the ATP bioluminescence reaction. 

Overall, 22 stressed microbial strains were examined during the study.

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