2 Mycobacterium avium Chester 1901 (Approved Lists 1980) emend. Thorel et al. 1990 Chiodini R.J. Abolish Mycobacterium paratuberculosis Strain 18 1993 31 7 1956 1958 Journal of Clinical Microbiology J Clin Microbiol 0095-1137 1098-660X 8123098 This strain was originally isolated in the 1920's by W.C. Hagan at Cornell University and was used as the "working type" for Mycobacterium paratuberculosis from 1939 until 1968, when it was de-accessioned by ATCC. The strain was used in a number of Mycobacterium paratuberculosis studies prior to its recognition as a laboratory contaminant.