Validation of Copan New FecalSwab Device for the Preservation of Clinical Specimens for the Detection of Enteric Pathogens

Introduction:
Collection, preservation and transportation of stools or rectal swab specimens are important for accurate laboratory diagnosis of pathogens causing gastrointestinal infections.
Copan is always improving the Liquid Based Microbiology (LBM) devices used with the Walk Away Specimens Processor (WASP). The FecalSwab device (a flocked swab and a tube with 2 ml of semi-liquid medium), has now been improved in order to be in compliance with the new CLSI M40-A2 standards. Moreover a fill line has been inserted on the label to indicate the maximum amount of sample to add.
Objective:
The objective of this study was evaluate Copan FecalSwab (FS) against Copan Cary-Blair Agar Gel transystem (CBT) to support the viability of enteric pathogens using ATCC strains according to the current CLSI M40-A2 standards.
Validation of Copan new FecalSwab device for the preservation of clinical specimens for the detection of enteric pathogens
Method:
•ATCC strains of S. typhimurium 14028, S. sonnei 9290, Y. enterocolitica 9610, E.coli 25922, E. faecalis 29212, C. jejuni 33291, V. paraheamolyticus 17802, C. difficile 9689, C. utilis 9950, E. faecium (VRE) 700221, E. faecalis (VRE) 51299, E. gallinarum 700425, E.coli O157-H7 (700728), C. utilis (9950) were used for this validation study.
•Bacteria suspension for each strain was prepared starting from a 0.5 McF, diluted tenfold in physiological saline to provide working suspensions of approximately 1.5 x 104 CFU/mL, 1.5 x 103 CFU/mL and 1.5 x102 CFU/mL.
•Both FS and CBT were inoculated with 100 uL of inoculum in order to obtain a valid time 0 colony count (25-250 CFU/plate) with the above concentrations.
•All testing was performed in triplicate at different times and temperature (6, 24, 48 hours at RT and 6, 24, 48, 72 hours at 40C). At each interval, all dilutions for both devices were plated by direct swabbing on appropriate agar plates. After incubation, colonies were counted and recorded.
•Results on CBT are not reported.
Results:

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Conclusions
:
•All bacterial strains were recovered at each storage time, except for C. difficile that was only recovered after 24 hours at RT and 48 hours at 4°C.
•FecalSwab was able to maintain bacteria viability at levels in compliance with the current CLSI M40-A2 standards.

Take home messages:
•Copan FecalSwab is a device for transferring, preserving and transporting stool samples that supports the viability of all relevant enteric pathogens.
•It can be used for collection of rectal swab or as transfer tool for feces.
•The improved labelling eliminates the risk of overloading the device with excess stool sample. Further studies with clinical fecal specimens are in progress foe validation of FecalSwab with molecular assays and rapid kits.