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Comparative performance of contact plates, electrostatic wipes, swabs and a novel sampling device for the detection of S taphylococcus aureus on environmental surfaces
Author(s) -
Lutz J.K.,
Crawford J.,
Hoet A.E.,
Wilkins J.R.,
Lee J.
Publication year - 2013
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12230
Subject(s) - staphylococcus aureus , veterinary medicine , inoculation , sampling (signal processing) , plate count , chromatography , chemistry , biology , bacteria , medicine , genetics , filter (signal processing) , computer science , immunology , computer vision
Abstract Aims To evaluate the performance of four sampling methods [contact plates, electrostatic wipes (wipe), swabs and a novel roller sampler] for recovery of Staphylococcus aureus from a stainless steel surface. Methods and Results Stainless steel test plates were inoculated with Staph. aureus , dried for 24 h and sampled using each of the four methods. Samples were either incubated directly (roller, contact plate) or processed using elution and membrane filtration (swab, wipe). Performance was assessed by calculating the apparent sampling efficiency ( ASE ), analytical sensitivity (Sn) and percentage of replications with positive growth. The wipe demonstrated the best performance across all inoculating concentrations ( ASE 48 h = 18%; Sn 48 h = 7 CFU per 100 cm 2 ). The swab performed well when corrected for area actually sampled ( ASE 48 h = 24%; Sn 48 h = 76 CFU per 100 cm 2 ). Of the contact‐based methods, the newly developed roller sampler outperformed the contact plate (roller: ASE 48 h = 10%; Sn 48 h = 17 CFU per 100 cm 2 ; contact plate: ASE 48 h = 0·04%; Sn 48 h = 1412 CFU per 100 cm 2 ); both contact samplers performed better at higher inoculating concentrations (6E3 CFU per 100 cm 2 for the roller and 6E6 CFU per 100 cm 2 for the contact plate). Overall, the electrostatic wipe produced the highest number of replications resulting in positive growth (74% 24 h , 91% 48 h ). Conclusions This study demonstrates that selection of the sampling method must be carefully considered, given that different methods have varying performance. Significance and Impact of the Study This is the first study assessing static wipes for sampling and one that uses a more real‐world‐relevant 24‐h drying time. The results help with infection control, and environmental health professionals choose better sampling methodologies.