Insights into Hematological Parameters of Male Wistar Rats: Implications as Model Organisms for Urinary Tract Infection Studies with Staphylococcus sp, Klebsiella sp, EPEC, and Bacillus sp

AbstractUrinary tract infections (UTIs) are common in companion animals and are frequently used in experimental models to elucidate pathophysiology and evaluate interventions. Uropathogenic Escherichia coli (UPEC) is the standard inducer; however, culturing UPEC necessitates biosafety level-2 facilities, which restrict accessibility. This study investigated a viable alternative by evaluating whether other easily managed bacteria can induce a UTI phenotype in rats and alter basic hematological parameters.Twenty male Wistar rats were allocated to receive transurethral inoculation with Staphylococcus sp., Klebsiella sp., enteropathogenic Escherichia coli (EPEC), or Bacillus sp. (1 × 10^8 CFU/mL, once daily for three days); a saline group served as the negative control. After induction, whole blood was analyzed for total erythrocyte count, hemoglobin, and hematocrit. Erythrocytes were counted manually with a hemocytometer at 400× magnification, hemoglobin was measured using the Sahli method, and hematocrit was read after microcentrifugation at 16,000 rpm for 5 minutes. Data were compared by one-way ANOVA (α=0.05) followed by Tukey’s test. Across treatments, none of the bacterial challenges produced statistically significant changes versus saline (p>0.05). Descriptively, Klebsiella sp. yielded the highest average erythrocyte count (4.24 ± 1.71 ×10^6 cells/mm^3) and hematocrit (41.5 ± 2.38%), whereas EPEC showed the lowest average hemoglobin (8.4 ± 0.43 g/dL). These findings suggest that, under the present conditions, transurethral inoculation with Staphylococcus sp., Klebsiella sp., EPEC, or Bacillus sp. does not measurably alter systemic hematological parameters in male Wistar rats. The protocol may therefore be insufficient to reproduce a robust UTI phenotype detectable by these indices alone. Future work should incorporate urine culture and urinalysis, histopathology of the urinary tract, inflammatory biomarkers, and refined dosing or timing to verify infection establishment. If confirmed, accessible organisms such as Klebsiella sp. could offer a feasible, lower-barrier model for UTI research where BSL-2 resources are constrained. Outcomes are presented as mean ± SD to aid interpretation and reproducibility here. Keywords: Urinary Tract Infection (UTI), bacteria, erythrocytes, hemoglobin, hematocrit