A model for analyzing growth kinetics of a slowly growing Mycobacterium sp

Abstract

This report describes a simple method for quantifying viable mycobacteria and for determining generation time. We used statistical models and computer analysis of growth curves generated for the slowly growing mycobacterium Mycobacterium paratuberculosis under controlled conditions to derive a mathematical formula relating the dependent variable, growth, to the independent variables, loglo number of organisms in the inoculum (inoculum size) and incubation time. Growth was measured by a radiometric method which detects 910

Fitness study of the RDRiolineage and Latin American–Mediterranean family ofMycobacterium tuberculosisin the city of Rio Grande, Brazil

“…There is no standard method to compare fitness in the laboratory. A growth curve has been considered as an optimal marker to compare fitness in other bacteria (Laurent et al, 2001) but in M. tuberculosis it is considered a difficult method due to its slow growth and tendency to form clumps when grown in liquid media (Lambrecht et al, 1988). In the present study we set up a new method to determine the growth curve of M. tuberculosis by measuring quantitatively the reduction of resazurin based on OD.…”

Evaluation of culture media for the recovery of Mycobacterium avium subsp. paratuberculosis from Cheddar cheese

“…The production of false-positive growth index readings in BACTEC cultures of Cheddar cheese, manufactured with these starters, has implications for the recovery of MAP from such cheeses. Furthermore, as the BACTEC method has been adopted for the enumeration of MAP (Lambrecht et al 1988;Sung and Collins 2000), the increasing growth index values observed for starter cultures R603 and R604 could result in an over estimation of the numbers of MAP present in the sample.…”

Comparative evaluation of the MGITTM and BACTEC culture systems for the recovery of Mycobacterium avium subsp. paratuberculosis from milk

“…The objectives of this study were threefold: (i) to compare the performance of the MGIT and BACTEC culture systems, in terms of detection times and minimum detection limits, with and without prior chemical decontamination of milk samples; (ii) to determine whether manual reading of MGIT tubes on an u.v. transilluminator, which is a subjective evaluation, yields differing results if several people read the tubes independently, and (iii) to assess whether there is the potential to relate MGIT detection time to log 10 number of M. paratuberculosis present and make the MGIT system quantitative as is currently possible with the BACTEC system using a published mathematical formula (Lambrecht et al. 1988).…”