Evidence map›Paper›PMID 26856815›Full record

ArticleBMC research notes2016

Validation of an automated colony counting system for group A Streptococcus.

H R Frost, S K Tsoi, C A Baker, D Laho, M L Sanderson-Smith, A C Steer, P R Smeesters

Open access · goldAbstract readValidation Study
In one paragraph

Article in BMC research notes, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers.

0numbers the graph read from it
0cells of the map it votes in
5citing papers in PubMed
0.9field-weighted citation impact, top 26% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

5 citing papers in PubMed, 13 citations in OpenAlex.

  1. Article
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    Article
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors at 2 institutions in 1 country.

H R FrostGroup A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia. Hannah.frost@mcri.edu.au.
S K TsoiGroup A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia. shuki.tsoi@gmail.com.
C A BakerGroup A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia. Ciara.baker@mcri.edu.au.
D LahoGroup A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia. Delphine.laho@mcri.edu.au.
M L Sanderson-SmithIllawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Wollongong, Australia. martina@uow.edu.au.
A C SteerGroup A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia. Andrew.steer@rch.org.au.
P R SmeestersGroup A Streptococcus Research Group, Murdoch Childrens Research Institute, Flemington Road, Parkville, Melbourne, VIC, 3052, Australia. pierre.smeesters@mcri.edu.au.
Murdoch Children's Research Institute · AUUniversity of Wollongong · AU

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThe practice of counting bacterial colony forming units on agar plates has long been used as a method to estimate the concentration of live bacteria in culture. However, due to the laborious and potentially error prone nature of this measurement technique, an alternative method is desirable. Recent technologic advancements have facilitated the development of automated colony counting systems, which reduce errors introduced during the manual counting process and recording of information. An additional benefit is the significant reduction in time taken to analyse colony counting data. Whilst automated counting procedures have been validated for a number of microorganisms, the process has not been successful for all bacteria due to the requirement for a relatively high contrast between bacterial colonies and growth medium. The purpose of this study was to validate an automated counting system for use with group A Streptococcus (GAS).

results

methodsTwenty-one different GAS strains, representative of major emm-types, were selected for assessment. In order to introduce the required contrast for automated counting, 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) dye was added to Todd-Hewitt broth with yeast extract (THY) agar. Growth on THY agar with TTC was compared with growth on blood agar and THY agar to ensure the dye was not detrimental to bacterial growth. Automated colony counts using a ProtoCOL 3 instrument were compared with manual counting to confirm accuracy over the stages of the growth cycle (latent, mid-log and stationary phases) and in a number of different assays. The average percentage differences between plating and counting methods were analysed using the Bland-Altman method.

conclusions

resultsA percentage difference of ±10 % was determined as the cut-off for a critical difference between plating and counting methods. All strains measured had an average difference of less than 10 % when plated on THY agar with TTC. This consistency was also observed over all phases of the growth cycle and when plated in blood following bactericidal assays. Agreement between these methods suggest the use of an automated colony counting technique for GAS will significantly reduce time spent counting bacteria to enable a more efficient and accurate measurement of bacteria concentration in culture.

Indexed as

AutomationBiological AssayColony Count, MicrobialHumansReproducibility of ResultsStreptococcus pyogenesTemperature

Identifiers

PMID26856815
PMCPMC4745170
OpenAlexW2258362492

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.