Rapid and retrievable recording of big data of time-lapse 3D shadow images of microbial colonies

Hiroyuki Ogawa,Mikako Saito,Motomu Takeshige,Hideaki Matsuoka,Senshi Nasu

doi:10.1038/srep10061

Hiroyuki Ogawa, Mikako Saito + Show 3 more

Open Access

https://doi.org/10.1038/srep10061

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Abstract

We formerly developed an automatic colony count system based on the time-lapse shadow image analysis (TSIA). Here this system has been upgraded and applied to practical rapid decision. A microbial sample was spread on/in an agar plate with 90 mm in diameter as homogeneously as possible. We could obtain the results with several strains that most of colonies appeared within a limited time span. Consequently the number of colonies reached a steady level (Nstdy) and then unchanged until the end of long culture time to give the confirmed value (Nconf). The equivalence of Nstdy and Nconf as well as the difference of times for Nstdy and Nconf determinations were statistically significant at p < 0.001. Nstdy meets the requirement of practical routines treating a large number of plates. The difference of Nstdy and Nconf, if any, may be elucidated by means of retrievable big data. Therefore Nconf is valid for official documentation.

Highlights

(b,c) time point of reaching a steady level (Nstdy) of Ni, (d) occurrence of delayed decrease of Ni, (e) unchanged steady level, (f) delayed increase of Ni
This time-lapse shadow image analysis (TSIA) enabled the distinction of a single colony generated from a single cell, a doublet colony generated from 2 cells, and a colony attached to a non-biological particle
Conventional methods for microbial colony measurement are based on the combination of an appropriate agar medium and culture conditions such as temperature and culture time

Summary

Introduction

(b,c) time point of reaching a steady level (Nstdy) of Ni, (d) occurrence of delayed decrease of Ni, (e) unchanged steady level, (f) delayed increase of Ni. Rapid decision of the number of colonies is intensively required under those practical conditions To meet these practical requirements, we developed a unique automated system for acquiring the 3D shadow image of every colony in the entire culture plate of 90 mm in diameter by single capture shot[18]. Time-lapse shadow images are captured automatically in a multi-focus mode while the plates under test are being incubated under traditional culture conditions. This time-lapse shadow image analysis (TSIA) enabled the distinction of a single colony generated from a single cell, a doublet colony generated from 2 cells, and a colony attached to a non-biological particle. We applied the system to the colony measurement of 4 strains and 2 contaminated food samples in order to demonstrate its performance of rapid decision of the number of colonies in a wide range of cell density

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