Evaluating the Differential Efficacy of Disinfectants Against Microbial Forms Using Logarithmic Reduction Analysis

Mostafa Essam Eissa¹

Keywords: Disinfectant efficacy, microbial resistance, ethanol, isopropyl alcohol, logarithmic reduction

DOI: 10.63475/yjm.v4i2.0101

DOI URL: https://doi.org/10.63475/yjm.v4i2.0101

Publish Date: 22-09-2025

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Pages: 339 - 348

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Downloads: 1

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Author Affiliation:

1 Pharmaceutical Scientist, Certified Six Sigma Green Belt, Independent Researcher and Freelance Consultant, Former Inspector in CAPA, Cairo, Egypt

Abstract

Background: Effective disinfection protocols are crucial in healthcare and pharmaceutical settings to mitigate infection and cross-contamination risks, especially with a growing immunocompromised population. Disinfectant efficacy varies, and understanding microbial resistance profiles is essential. This study aimed to evaluate the differential efficacy of ethanol (ET), isopropyl alcohol (IPA), and a peracetic acid-hydrogen peroxide (PA+HP) blend against

diverse microbial forms (bacterial spores, fungal spores, and vegetative yeast cells) and to analyze differences in susceptibility.

Methods: The efficacy of ET, IPA, and PA+HP was evaluated against Bacillus subtilis (bacterial spores), Aspergillus niger (fungal spores), Candida albicans, and Kocuria rosea (vegetative yeast cells). Logarithmic reduction (LR) values from 10 replicates per group were analyzed using nonparametric (Friedman test with Dunn’s post-hoc) and two-way omnibus tests.

Results: The Friedman test revealed significant differences across microbial groups (p < 0.0001). B. subtilis showed maximal susceptibility (LR = 6.70 ± 0.00), while A. niger exhibited minimal susceptibility (LR = 3.77 ± 0.21). ET outperformed IPA against C. albicans (LR = 5.43 vs. 4.91, p = 0.0232). The microbial group accounted for 92.36% of the variance (p < 0.0001).

Conclusions: Microorganism-specific disinfection strategies were emphasized by the findings. A routine disinfectant evaluation program is crucial to mitigate microbial infection and crosscontamination risk in healthcare settings. The study highlights the importance of selecting appropriate disinfectants based on microbial resistance profiles.

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