E-ISSN 2536-9520 | ISSN 1110-2047
 
2026, Vol: 88
88Current Volume Online First Archive Aims and Scope Abstracting & Indexing Most Accessed Articles Most Downloaded Articles Most Cited Articles

Original Article 


Performance Characteristics and Estimation of Measurement Uncertainty of Colony Count Procedures for the Evaluation of Live Bacterial Poultry Vaccines

Afaf A. Khedr, Fatma El-zahraa Gamal, Eman M. Soliman, Samir A. Nassif.


Abstract
This study aimed to validate the colony-count assay as a quantitative in vitro alternative to the traditional in vivo challenge method for evaluating live bacterial poultry vaccines. Live E. coli, Salmonella enteritidis, and Salmonella typhimurium vaccines were assessed for performance characteristics, estimation of measurement uncertainty, and vial-to-vial homogeneity. The assay was conducted on thirteen vials from each vaccine batch; three vials were used for determining repeatability, reproducibility, and measurement uncertainty (MU), while ten vials were used for homogeneity evaluation. The colony-count procedure demonstrated high precision with within-analyst standard deviation ranging from 0.012-0.026 log10 CFU and between-analyst standard deviation ranging from 0.0111- 0.0606 log10 CFU and relative expanded uncertainty of approximately 0.96%. One-way ANOVA and F-tests revealed no significant differences among vials for any vaccine confirming excellent batch homogeneity. These findings indicate that the colony-count method provides accurate, precise, and reproducible quantification of viable organisms in live bacterial poultry vaccines supporting its use as a scientifically robust and ethically sound in vitro alternative to animal-based challenge testing for vaccine potency assessment.

Key words: Vaccines, Colony Count, Performance Characteristics, Measurement Uncertainty, Homogeneity


 
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How to Cite this Article
Pubmed Style

Khedr AA, Gamal FE, Soliman EM, Nassif SA. Performance Characteristics and Estimation of Measurement Uncertainty of Colony Count Procedures for the Evaluation of Live Bacterial Poultry Vaccines. AJVS. 2026; 88(0): 89-99. doi:10.5455/ajvs.299628

Web Style

Khedr AA, Gamal FE, Soliman EM, Nassif SA. Performance Characteristics and Estimation of Measurement Uncertainty of Colony Count Procedures for the Evaluation of Live Bacterial Poultry Vaccines. https://www.alexjvs.com/?mno=299628 [Access: February 04, 2026]. doi:10.5455/ajvs.299628

AMA (American Medical Association) Style

Khedr AA, Gamal FE, Soliman EM, Nassif SA. Performance Characteristics and Estimation of Measurement Uncertainty of Colony Count Procedures for the Evaluation of Live Bacterial Poultry Vaccines. AJVS. 2026; 88(0): 89-99. doi:10.5455/ajvs.299628


Vancouver/ICMJE Style

Khedr AA, Gamal FE, Soliman EM, Nassif SA. Performance Characteristics and Estimation of Measurement Uncertainty of Colony Count Procedures for the Evaluation of Live Bacterial Poultry Vaccines. AJVS. (2026), [cited February 04, 2026]; 88(0): 89-99. doi:10.5455/ajvs.299628


Harvard Style

Khedr, A. A., Gamal, . F. E., Soliman, . E. M. & Nassif, . S. A. (2026) Performance Characteristics and Estimation of Measurement Uncertainty of Colony Count Procedures for the Evaluation of Live Bacterial Poultry Vaccines. AJVS, 88 (0), 89-99. doi:10.5455/ajvs.299628


Turabian Style

Khedr, Afaf A., Fatma El-zahraa Gamal, Eman M. Soliman, and Samir A. Nassif. 2026. Performance Characteristics and Estimation of Measurement Uncertainty of Colony Count Procedures for the Evaluation of Live Bacterial Poultry Vaccines. Alexandria Journal of Veterinary Sciences, 88 (0), 89-99. doi:10.5455/ajvs.299628


Chicago Style

Khedr, Afaf A., Fatma El-zahraa Gamal, Eman M. Soliman, and Samir A. Nassif. "Performance Characteristics and Estimation of Measurement Uncertainty of Colony Count Procedures for the Evaluation of Live Bacterial Poultry Vaccines." Alexandria Journal of Veterinary Sciences 88 (2026), 89-99. doi:10.5455/ajvs.299628


MLA (The Modern Language Association) Style

Khedr, Afaf A., Fatma El-zahraa Gamal, Eman M. Soliman, and Samir A. Nassif. "Performance Characteristics and Estimation of Measurement Uncertainty of Colony Count Procedures for the Evaluation of Live Bacterial Poultry Vaccines." Alexandria Journal of Veterinary Sciences 88.0 (2026), 89-99. Print. doi:10.5455/ajvs.299628


APA (American Psychological Association) Style

Khedr, A. A., Gamal, . F. E., Soliman, . E. M. & Nassif, . S. A. (2026) Performance Characteristics and Estimation of Measurement Uncertainty of Colony Count Procedures for the Evaluation of Live Bacterial Poultry Vaccines. Alexandria Journal of Veterinary Sciences, 88 (0), 89-99. doi:10.5455/ajvs.299628




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    About Alexandria Journal of Veterinary Sciences

    The Alexandria Journal of Veterinary Sciences (AJVS) Official Journal of Faculty of Veterinary Medicine, Alexandria University   ISSN: 1110-204 ... Read more.



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    Faculty of Veterinary Medicine
    Alexandria University
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    Abees 10th district, Alexandria
    Egypt.

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