SURFACE SAMPLING FOR B. ANTHRACIS SPORES ON NONPOROUS SURFACE – EXTRACTION EFFICIENCY

 

DA SILVA Sandra and MORROW Jayne

Biochemical Science Division, NIST, division 831, A162 (Lab.), B158 (Office), building 227, mail stop 8312, Phone: 301-975 4665, Fax: 301-977 0587, sdasilva@nist.gov, Gaithersburg, MD 20899.

 

         The objective of this work is to address gaps in existing standard procedures for environmental sampling of B. Anthracis spores on nonporous surfaces. The protocol can be divided in two main steps: extraction efficiency and recovery efficiency which contribute significantly to determining the efficiency of the overall sampling procedure. The extraction efficiency measures the ability of the absorptive material (wipe or swab) to release spores from its surface to the extraction solution while recovery efficiency measures the efficiency of the absorptive material to collect spores from surfaces such as glass and stainless steel under different conditions. Polyester/rayon, cotton and polyester wipes were used as absorptive materials. Phosphate buffered saline (PBS), sterile water, 0.04% Tween 80 in sterile water, and 0.04% Tween 80 in PBS (PBST) were used as extraction solutions to pre-moisten wipes as well as extract the spores for quantification. Sonication and vortexing were chosen as physical dissociation methods for enhanced extraction1,2. The extraction solution was found to have a significant effect on extraction efficiency. While Tween 80 increased the wipe extraction, PBS and PBST showed poor performance. Mass balances and proper controls demonstrated strong association between the spores and the centrifuge tubes used in the spore extraction methods. The optimal combination of absorptive material, extraction solution and physical dissociation method were determined for enhanced performance of the extraction step. The development of a standard wipe method for spores deposited on surfaces is critical to account for efficiency perturbations on sampling capabilities as well as advancing wipe surface sampling technology for both biodefense and clean room applications.

           

 

 [1] Rose, L.; Jensen, B.; Peterson, A.; Banerjee, S. N.; Arduino, M. J. 2004. Swab materials and Bacillus anthracis recovery from nonporous surfaces. Emerg. Infect. Dis. 10(6): 1023-1029.  

[2] Brown, G. S.; Betty, R. G.; Brockmann, J. E.; Lucero, D. A.; Souza, C. A.; Walsh, K. S.; Boucher, R. M.; Tezak, M.; Wilson, M. C.; Rudolph, T. 2007. Evaluation of a wipe surface sample method for collection of Bacillus spores from nonporous surfaces. Appl. Environm. Microbiol. 73(3): 706-720.


CATEGORY: Biology

Mentors Name: Jayne Morrow

Division 831, Laboratories A162 and A214

Room A215, Building 227, Mail stop 8312

Tel: 301-975 6722, Fax: …………….., E-mail: jmorrow@nist.gov

 

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