title: Automated Scoring of Chromogenic Media for Detection of Methicillin-Resistant Staphylococcus aureus by Use of WASPLab Image Analysis Software.
abstract: Recently, systems have been developed to create total laboratory automation for clinical microbiology. These systems allow for the automation of specimen processing, specimen incubation, and imaging of bacterial growth. In this study, we used the WASPLab to validate software that discriminates and segregates positive and negative chromogenic methicillin-resistant Staphylococcus aureus (MRSA) plates by recognition of pigmented colonies. A total of 57,690 swabs submitted for MRSA screening were enrolled in the study. Four sites enrolled specimens following their standard of care. Chromogenic agar used at these sites included MRSASelect (Bio-Rad Laboratories, Redmond, WA), chromID MRSA (bioMérieux, Marcy l'Etoile, France), and CHROMagar MRSA (BD Diagnostics, Sparks, MD). Specimens were plated and incubated using the WASPLab. The digital camera took images at 0 and 16 to 24 h and the WASPLab software determined the presence of positive colonies based on a hue, saturation, and value (HSV) score. If the HSV score fell within a defined threshold, the plate was called positive. The performance of the digital analysis was compared to manual reading. Overall, the digital software had a sensitivity of 100% and a specificity of 90.7% with the specificity ranging between 90.0 and 96.0 across all sites. The results were similar using the three different agars with a sensitivity of 100% and specificity ranging between 90.7 and 92.4%. These data demonstrate that automated digital analysis can be used to accurately sort positive from negative chromogenic agar cultures regardless of the pigmentation produced.
authors.affiliation: Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Faron
authors.affiliation: Medical College of Wisconsin, Milwaukee, Wisconsin, USA Wisconsin Diagnostic Laboratories, Milwaukee, Wisconsin, USA.
authors.forename: Blake W
authors.identifier: http://orcid.org/0000-0002-4111-048X
authors.initials: BW
authors.lastname: Buchan
authors.affiliation: A. O. Ospedale Niguarda Cà Granda, Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Vismara
authors.affiliation: A. O. Ospedale Niguarda Cà Granda, Milan, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Lacchini
authors.affiliation: A. O. Ospedale Niguarda Cà Granda, Milan, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bielli
authors.affiliation: A. O. Ospedale Niguarda Cà Granda, Milan, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gesu
authors.affiliation: PAMM Laboratory of Medical Microbiology, Veldhoven, Netherlands.
authors.forename: Theo
authors.initials: T
authors.lastname: Liebregts
authors.affiliation: PAMM Laboratory of Medical Microbiology, Veldhoven, Netherlands.
authors.forename: Anita
authors.initials: A
authors.lastname: van Bree
authors.affiliation: PAMM Laboratory of Medical Microbiology, Veldhoven, Netherlands.
authors.forename: Arjan
authors.initials: A
authors.lastname: Jansz
authors.affiliation: CHU de Quebec-Universite Laval, Quebec City, Quebec, Canada.
authors.forename: Genevieve
authors.initials: G
authors.lastname: Soucy
authors.affiliation: Hamilton General Hospital, Hamilton, Ontario, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Korver
authors.affiliation: Medical College of Wisconsin, Milwaukee, Wisconsin, USA Wisconsin Diagnostic Laboratories, Milwaukee, Wisconsin, USA nledeboe@mcw.edu.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Ledeboer
mesh_terms: D057205:Automation, Laboratory / Q000379:methods*; D001431:Bacteriological Techniques / Q000379:methods*; D002863:Chromogenic Compounds / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D012984:Software; D013203:Staphylococcal Infections / Q000175:diagnosis*
chemical_list: D002863:Chromogenic Compounds; D003470:Culture Media