Microbial Contamination in Saturated Saline Solution Used for Cadaver Preservation in Veterinary Anatomy Teaching

Abstract

Background: The use of animal cadavers is essential for veterinary anatomy education, requiring preservation methods that maintain tissue characteristics similar to those of living organisms. At CESPU, cadavers are preserved using a saturated saline (SS) solution, considered effective in maintaining tissue texture, color, and joint mobility [1,2]. However, its ability to control microbial growth, particularly for halotolerant strains, remains poorly studied [3]. Common bacterial species associated with animal cadavers include Staphylococcus aureus, Bacillus spp., Enterococcus spp., and Escherichia coli [4]. Objectives: This study aimed to detect fecal contamination indicators, namely Enterococcus spp. and E. coli, in the SS solution used for preserving animal cadavers in veterinary anatomy classes at CESPU. Methods: A total of 42 SS samples were collected from 7 cadavers (3 cats and 4 dogs), including samples obtained before immersion and after 7, 14, and 21 days of preservation. The SS solution was renewed weekly, with each cadaver immersed for 7 days before replacement. Samples were inoculated onto selective media: Slanetz-Bartley agar and Kanamycin Esculin Azide agar for Enterococcus spp., and MacConkey agar and Chromogenic Coliform agar for E. coli. Up to two typical colonies per sample were subcultured on brain heart infusion agar and identified using MALDI-TOF mass spectrometry. Results: Among the 21 SS samples collected before cadaver immersion, 1 showed bacterial growth, yielding two isolates: Enterococcus hirae and E. coli. Of the 21 samples collected after immersion, 15 showed microbial growth. Identified isolates included Enterococcus faecalis (n=2), Enterococcus faecium (n=3), Enterococcus hirae (n=1), Enterococcus raffinosus (n=1), and Enterococcus spp. (n=7). Enterococci were detected in samples collected at 7 (n=5), 14 (n=4), and 21 days (n=5). Additionally, two E. coli isolates were recovered from a single sample collected at 14 days. Conclusion: These findings indicate that the SS solution does not fully inhibit microbial growth during cadaver preservation. The detection of Enterococcus spp. and E. coli, particularly after immersion, suggests possible fecal contamination and highlights the need for regular microbiological monitoring and enhanced biosafety measures to reduce occupational exposure and ensure a safer learning environment.