Comparison of two methods for microbiological control of isolator for reconstitution unit of cytotoxic drugs
6 October 2017
E. Lopez1, S. Toubal2, F. Clément2, B. Cortes1, L. Cadot1, D. Castel1 1 CH Ales-Cévennes, 811 Av. du Docteur Jean Goubert, 30100 Alès, France2 CHU Montpellier, 371 Av. du Doyen Gaston Giraud, 34000 Montpellier, France
Objectives
Evaluate the reliability of microbiological samples taken by agar impression, compared to a dry swab at the same sampling points. Evaluate the relevance of swab for hard-to-access areas.
Methods
Controls conducted over 4 weeks by agar impression (count-tact agar) and by dry swab after the last preparation session and before bio cleaning. They cover the interior, isolator air-locks and the external environment (benches). A weekly cadence setting defines the sampling points. Contact plates were incubated at 30 ° C. TSB-T culture broths are inoculated with the swabs and then transplanted onto COS agar. After 72 h of incubation, results are interpreted according to the Good Preparation Practices (GPP) guidelines.
Results
Week 1: positive growth on the agar sample from the external closed-system preparation bench (3 CFU / 25cm²).
Weeks 2 and 3: all results are negative.
Week 4: two positive samples on agar from the preparation bench in closed-system (9 CFU / 25cm²).
Morphological identification isolated bacteria of the genus Staphylococcus and Micrococcus sp. The same week, an air-lock swab of the isolator was positive with gram positive cocci (probably Staphylococcus sp). A remote sampling (1 week) from the same point was negative suspecting transient contamination.
Conclusion
The results of both methods are below thresholds and / or with non-pathogenic germs. The isolator is "GPP compliant". The two methods are complementary. The agar print, easily standardized, allows a qualitative and quantitative analysis. It will be kept as a reference method. Swabbing allows the analysis of hard-to-access areas, but only allows qualitative control after enrichment. Its installation for the routine sampling of hard-to-access areas of the isolator is conceivable.