Data Analysis Plan

Data Analysis Plan A. Identification of Fermented Foods Containing Lactobacillus casei and the tetM Gene To identify the presence of Lactobacillus casei and the tetM gene in different fermented food types, including cheddar cheese, kefir, Sicilian green olives, and yogurt, the number of positive isolates will be recorded for each food category. A frequency distribution analysis will be conducted to determine the prevalence of L. casei and the tetM gene across the selected fermented foods, providing a comparative overview of their occurrence. B. Antibiotic Resistance Profiles of L. casei Strains The antibiotic susceptibility of Lactobacillus casei strains will be assessed using the zone of inhibition measured by the disk diffusion method and minimum inhibitory concentration (MIC) values determined through the microdilution method. The mean, standard deviation, and range will be calculated for both susceptibility metrics. A one-way analysis of variance (ANOVA) will be conducted to evaluate significant differences in resistance levels among isolates obtained from different fermented food sources. Additionally, the susceptibility classifications will be compared against Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints to categorize the strains as resistant (R), intermediate (I), or sensitive (S). C. Effect of tetM Gene Presence on Resistance A one-way analysis of variance (ANOVA) will be performed to determine whether significant differences exist in resistance levels, measured by the zone of inhibition and minimum inhibitory concentration (MIC) values, between Lactobacillus casei isolates that test positive and negative for the tetM gene. This analysis will evaluate the potential association between the presence of the tetM gene and increased tetracycline resistance. D. Variations in Resistance Across Different Fermented Foods A one-way analysis of variance (ANOVA) will be conducted to compare antibiotic resistance levels among Lactobacillus casei isolates obtained from cheddar cheese, kefir, Sicilian green olives, and yogurt. A significance level of p < 0.05 will be applied to assess whether resistance levels differ significantly among the food sources. In the event of significant differences, a post-hoc Tukey’s test will be performed to identify specific food groups that exhibit notable variations in resistance. E. Visual Representations To effectively present the findings, various visual representations will be utilized. A bar graph will depict the prevalence of the tetM gene among L. casei isolates from different food sources. A box plot will be used to illustrate the distribution of the zone of inhibition and MIC values across the fermented food groups, highlighting variations in resistance levels. Additionally, a scatterplot will be generated to visualize the relationship between tetM gene presence and resistance metrics, including the zone of inhibition and MIC values. F. Interpretation of Statistical Findings The results of the ANOVA test will provide insights into the variability of antibiotic resistance among L. casei isolates from different food sources, as well as differences between tetM-positive and tetM-negative isolates. Statistically significant findings will indicate that both the source of isolation and the presence of the tetM gene contribute to variations in tetracycline resistance. These results will serve as the basis for further analysis and interpretation.