A statistical model for assessing sample size for bacterial colony selection: a case study of Escherichia coli and avian cellulitis.
J Vet Diagn Invest
; 12(2): 118-25, 2000 Mar.
Article
em En
| MEDLINE
| ID: mdl-10730939
ABSTRACT
A general problem for microbiologists is determining the number of phenotypically similar colonies growing on an agar plate that must be analyzed in order to be confident of identifying all of the different strains present in the sample. If a specified number of colonies is picked from a plate on which the number of unique strains of bacteria is unknown, assigning a probability of correctly identifying all of the strains present on the plate is not a simple task. With Escherichia coli of avian cellulitis origin as a case study, a statistical model was designed that would delineate sample sizes for efficient and consistent identification of all the strains of phenotypically similar bacteria in a clinical sample. This model enables the microbiologist to calculate the probability that all of the strains contained within the sample are correctly identified and to generate probability-based sample sizes for colony identification. The probability of cellulitis lesions containing a single strain of E. coli was 95.4%. If one E. coli strain is observed out of three colonies randomly selected from a future agar plate, the probability is 98.8% that only one strain is on the plate. These results are specific for this cellulitis E. coli scenario. For systems in which the number of bacterial strains per sample is variable, this model provides a quantitative means by which sample sizes can be determined.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Doenças das Aves
/
Celulite (Flegmão)
/
Modelos Estatísticos
/
Escherichia coli
/
Infecções por Escherichia coli
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2000
Tipo de documento:
Article