Biofilm-associated virulence in Enterococcus isolates from poultry: Comparative gene distribution and statistical gene-phenotype associations

Enterococcus species have emerged as notable opportunistic microorganisms within the food chain due to their remarkable environmental persistence, physiological adaptability, ability to generate biofilms, and carriage of specific virulence-associated genes. This study focused on the detection of five major virulence genes gelE, asa1, esp, cylA, and hyl and evaluation of biofilm-forming ability among Enterococcus isolates derived solely from retail poultry meat samples. A total of 150 poultry meat samples were collected from retail outlets, of which 84 showed presumptive positivity, and 80 were molecularly confirmed as Enterococcus. Biofilm formation was assessed using Congo Red Agar (CRA), while virulence gene identification was confirmed through PCR. The prevalence of virulence genes among isolates was highest for gelE (88.75%), followed by asa1 (40.47%), esp (15%), and cylA (11.25%), with no hyl gene observed. Biofilm formation was detected in 90% of isolates, yet statistical evaluation using Chi-square and Fisher’s exact tests revealed a significant association only with cylA (p = 0.042), contrary to general expectations about gelE and asa1, which although frequent among strong biofilm producers, did not show statistical significance (p>0.05). These findings highlight the persistence potential of Enterococcus in poultry processing environments and reinforce the importance of improved sanitation strategies to prevent biofilm-mediated contamination. The study concludes by emphasizing the need for advanced molecular tracking, quantitative biofilm assessment, and expanded sampling in future investigations.