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The use of spiral plating and microscopic colony counting for the rapid quantitation of Mycobacterium paratuberculosis
Author(s) -
Smith W.L.,
McGarvey K.L.,
Cullor J.S.
Publication year - 2003
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1472-765x.2003.01311.x
Subject(s) - paratuberculosis , incubation , agar , microbiology and biotechnology , incubation period , mycobacterium , biology , agar plate , colony forming unit , plating (geology) , bacteria , paleontology , biochemistry , genetics
Aims: To evaluate a spiral plating and microscopic colony counting technique to hasten the quantitation of Mycobacterium paratuberculosis . Methods and Results: Broth and milk cultures of M. paratuberculosis were spirally plated onto Middlebrook agar plates and microscopically counted at 8 and 14 days of incubation. The same plates were recounted at 27–28 days of incubation when grossly visible colonies were present. The results were statistically compared with no difference in CFU ml −1 derived from the shorter vs longer incubation times. Other mycobacteria isolates were also plated and microscopically examined and found to be easily distinguishable from M. paratuberculosis . Conclusions: Microscopic quantitation of spirally plated M. paratuberculosis cultures can be achieved within 8–14 days of plate incubation and compare favourably to counts derived after prolonged incubations. Significance and Impact of the Study: The technique could greatly hasten the quantitation of viable M. paratuberculosis .