title: Automatic Digital Analysis of Chromogenic Media for Vancomycin-Resistant-Enterococcus Screens Using Copan WASPLab.
abstract: Vancomycin-resistant enterococci (VRE) are an important cause of health care-acquired infections (HAIs). Studies have shown that active surveillance of high-risk patients for VRE colonization can aid in reducing HAIs; however, these screens generate a significant cost to the laboratory and health care system. Digital imaging capable of differentiating negative and "nonnegative" chromogenic agar can reduce the labor cost of these screens and potentially improve patient care. In this study, we evaluated the performance of the WASPLab Chromogenic Detection Module (CDM) (Copan, Brescia, Italy) software to analyze VRE chromogenic agar and compared the results to technologist plate reading. Specimens collected at 3 laboratories were cultured using the WASPLab CDM and plated to each site's standard-of-care chromogenic media, which included Colorex VRE (BioMed Diagnostics, White City, OR) or Oxoid VRE (Oxoid, Basingstoke, United Kingdom). Digital images were scored using the CDM software after 24 or 40 h of growth, and all manual reading was performed using digital images on a high-definition (HD) monitor. In total, 104,730 specimens were enrolled and automation agreed with manual analysis for 90.1% of all specimens tested, with sensitivity and specificity of 100% and 89.5%, respectively. Automation results were discordant for 10,348 specimens, and all discordant images were reviewed by a laboratory supervisor or director. After a second review, 499 specimens were identified as representing missed positive cultures falsely called negative by the technologist, 1,616 were identified as containing borderline color results (negative result but with no package insert color visible), and 8,234 specimens were identified as containing colorimetric pigmentation due to residual matrix from the specimen or yeast (Candida). Overall, the CDM was accurate at identifying negative VRE plates, which comprised 84% (87,973) of the specimens in this study.
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: 0000-0002-4111-048X
authors.initials: BW
authors.lastname: Buchan
authors.affiliation: Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Coon
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 R
authors.initials: AR
authors.lastname: Jansz
authors.affiliation: CHU de Quebec-Universite Laval, Quebec City, Canada.
authors.forename: Genevieve
authors.initials: G
authors.lastname: Soucy
authors.affiliation: Hamilton Regional Laboratory Medicine Program, Hamilton Health Sciences, 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*; D003951:Diagnostic Errors; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008403:Mass Screening / Q000379:methods*; D061848:Optical Imaging / Q000379:methods; D012680:Sensitivity and Specificity; D065507:Vancomycin-Resistant Enterococci / Q000302:isolation & purification*
chemical_list: D002863:Chromogenic Compounds; D003470:Culture Media