First comprehensive molecular and phenotypic insights into multidrug resistance and virulence in poultry-associated Enterococcus spp. in Algeria.

BACKGROUND: Enterococci are common members of the gastrointestinal microbiota of humans and animals, but can act as opportunistic pathogens with a strong ability to acquire and disseminate antibiotic resistance, representing a significant public health concern. Surveillance in poultry is essential to monitor the spread of resistant enterococci along the food production chain. This study aimed to characterize the antimicrobial resistance and virulence profiles of Enterococcus species isolated from poultry in Algeria. METHODS AND RESULTS: A total of 163 cloacal swabs were collected from broiler chickens, laying hens, and turkeys in breeding centers and slaughterhouses located in the provinces of Bouira and Tizi-Ouzou. Enterococci were identified using biochemical methods and MALDI-TOF MS. Antimicrobial susceptibility was assessed by disk diffusion, phenotypic traits were evaluated, and resistance and virulence genes were detected by PCR. Among 163 analyzed samples, 102 isolates (62.6%) were identified as Enterococcus spp., including E. faecium (61.8%), E. faecalis (31.4%), E. hirae (3.9%), and E. gallinarum (2.9%). High resistance rates were observed to tetracycline (96.1%), erythromycin (95.1%), and ciprofloxacin (64.7%). Multidrug resistance was detected in 96.1% of isolates. Biofilm formation was observed in 75.5% of strains, while 70.6% were slime producers. The most prevalent resistance genes were ermB (81.4%), tetM (55.9%), and tetK (49%). Virulence genes, including ace, efaA, gelE, asa1, hyl, and cylA, were variably detected. CONCLUSIONS: The high prevalence of multidrug resistance and virulence determinants in poultry-associated enterococci highlights the need for strengthened antimicrobial stewardship, biosecurity measures, and surveillance to limit zoonotic transmission.