title: Development of an automatic identification algorithm for antibiogram analysis.
abstract: Routinely, diagnostic and microbiology laboratories perform antibiogram analysis which can present some difficulties leading to misreadings and intra and inter-reader deviations. An Automatic Identification Algorithm (AIA) has been proposed as a solution to overcome some issues associated with the disc diffusion method, which is the main goal of this work. AIA allows automatic scanning of inhibition zones obtained by antibiograms. More than 60 environmental isolates were tested using susceptibility tests which were performed for 12 different antibiotics for a total of 756 readings. Plate images were acquired and classified as standard or oddity. The inhibition zones were measured using the AIA and results were compared with reference method (human reading), using weighted kappa index and statistical analysis to evaluate, respectively, inter-reader agreement and correlation between AIA-based and human-based reading. Agreements were observed in 88% cases and 89% of the tests showed no difference or a <4mm difference between AIA and human analysis, exhibiting a correlation index of 0.85 for all images, 0.90 for standards and 0.80 for oddities with no significant difference between automatic and manual method. AIA resolved some reading problems such as overlapping inhibition zones, imperfect microorganism seeding, non-homogeneity of the circumference, partial action of the antimicrobial, and formation of a second halo of inhibition. Furthermore, AIA proved to overcome some of the limitations observed in other automatic methods. Therefore, AIA may be a practical tool for automated reading of antibiograms in diagnostic and microbiology laboratories.
authors.affiliation: LIPIS - Laboratory of Instrumentation, Image and Signal Processing, Gama Campus, University of Brasília, Brazil. Electronic address: luanfrc@gmail.com.
authors.forename: Luan F R
authors.initials: LF
authors.lastname: Costa
authors.affiliation: LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Portugal. Electronic address: eduardossilva06@gmail.com.
authors.forename: Eduardo S
authors.initials: ES
authors.lastname: da Silva
authors.affiliation: LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Portugal. Electronic address: victor.tn@outlook.com.
authors.forename: Victor T
authors.initials: VT
authors.lastname: Noronha
authors.affiliation: LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Portugal; CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Portugal. Electronic address: ivone@fe.up.pt.
authors.forename: Ivone
authors.initials: I
authors.lastname: Vaz-Moreira
authors.affiliation: LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Portugal. Electronic address: opnunes@fe.up.pt.
authors.forename: Olga C
authors.initials: OC
authors.lastname: Nunes
authors.affiliation: LIPIS - Laboratory of Instrumentation, Image and Signal Processing, Gama Campus, University of Brasília, Brazil. Electronic address: andrade@unb.br.
authors.forename: Marcelino M de
authors.initials: MM
authors.lastname: Andrade
mesh_terms: D000465:Algorithms; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D018407:Bacterial Physiological Phenomena / Q000187:drug effects*; D000069550:Machine Learning; D008826:Microbial Sensitivity Tests / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antibiogram; Automatic measuring; Disc diffusion method; Discs labels; Inhibition zone