Molecular characterization of histidine and tyrosine decarboxylating Enterococcus species isolated from some milk products

• DOI: 10.1186/s12866-025-03940-6
• Publication Date: 2025-04-23T02:45:37Z
• Authors: Obeid Shanab; Faten Fareed; Ahmed Y. Nassar; Hanan H. Abd-Elha...; Ahmed Shaban Ahmed; Mona A. El-Zamkan
• Keywords: Enterococcus faecium; Tyramine; Enterococcus faecalis

Abstract Background Fermented foods can cause adverse effects on human health because of the biogenic amines (BAs) accumulating through amino acid decarboxylation. This study investigated presence BAs including tyramine and histamine in 240 samples some cheese fermented milk using high-performance liquid chromatography. Another aim this is to isolate identify Enterococcus spp. as most important frequent BA producer examined samples. The isolated was phenotypically for their capacity produce decarboxylase enzyme microplate assay, genotypically molecular detection genes encoding decarboxylation ( tyrdc hdc ). Biogenic producing enterococci were then antimicrobial resistance, biofilm production well virulence determinants. Results Tyramine could be detected 86.7 87.9% with 52.9% being contaminated Significant correlation between incidence Enterococci formed P < 0.0001). 85 5% decarboxylating spp., respectively. A high percentage isolates (57.5%) multidrug-resistant resistance against penicillin widespread among followed by tetracycline, vancomycin, erythromycin linezolid. Also, 77.5% capable forming biofilms a highly significant 0.0001) found formation multidrug resistance. results showed that rates gelE , esp ace asa1 cylA 77.5. 47.5, 35 7.5%, respectively, while hyl gene not any isolates. Conclusion highlights (TYM HIS) samples, strong contamination TYM production. prevalence tyramine-producing species poses notable public concern especially multidrug-resistant, dairy products, emphasizing urgent need improved stewardship food producers veterinarians mitigate risk transferring resistant strains humans.