Rojas Jaimes, J.Giraldo-Chavez, J.Huyhua-Flores, Y.Caceres-Nakiche, T.6/22/20222022-09-306/22/20222022-09-302018https://doi.org/10.17843/rpmesp.2018.352.3471With the aim of identifying morphological differences in colonies of different species of mycobacteria by means of inverted phase microscopy, nine species of high-prevalence pathogenic mycobacteria were seeded in 7H11 solid medium and were observed for up to 21 days. Additionally, Ziehl-Neelsen (ZN) stains were carried out for each one of them. No morphological variations were identified among the species grown on solid medium; however, it was identified that all are able to form cords in solid medium in an early stage of growth, being corroborated by the Ziehl-Neelsen stain in Mycobacterium tuberculosis. so techniques based on detecting M. tuberculosis depending on the identification of the cords should be taken with caution so as not to generate a bad diagnosis, so microbiological characteristics could also be established as a minimum time to detect growth, temperature of growth and bacillary characteristics based on the Ziehl-Neelsen stain for each species studied. © 2018, Instituto Nacional de Salud. All rights reserved.application/pdfspainfo:eu-repo/semantics/closedAccessMedicineinfo:eu-repo/semantics/article10.17843/rpmesp.2018.352.3471http://purl.org/pe-repo/ocde/ford#3.00.00