Researchers from Zagazig University and the Animal Health Research Institute in Egypt conducted an integrated One Health analysis linking food contamination, occupational exposure, and human colonization through Enterococcus isolates gathered from retail meat, retail market workers, and consumers.

The researchers collected 250 samples between April and June 2025, including 150 retail meat samples (with an equal number of chicken, beef, and camel meat), as well as 100 human stool samples from 50 retail market workers and 50 consumers.

Overall, 50 Enterococcus isolates were recovered, representing 20 percent of the samples. Beef had the highest prevalence at 30 percent, followed by chicken at 26 percent and camel meat at 14 percent. Among the human samples, Enterococcus was recovered from 16 percent of retail workers and 14 percent of consumers. Only E. faecalis was recovered from retail workers (16 percent), while E. faecium was the most prevalent from consumers (12 percent).

High Levels of Multidrug Resistance Detected

The researchers evaluated 27 E. faecalis and 23 E. faecium isolates against 14 antimicrobials representing nine different classes of drugs.

Multidrug resistance was observed in 88 percent of isolates. Resistance was highest for rifampin, at 94 percent of isolates, followed by erythromycin and tetracycline, both at 88 percent. Resistance to trimethoprim/sulfamethoxazole was reported in 54 percent of isolates. Moderate resistance was observed for several fluoroquinolones, including ciprofloxacin (34 percent), norfloxacin (32 percent), and levofloxacin (24 percent).

In contrast, vancomycin resistance was detected in only 8 percent of isolates, while resistance to penicillin and gatifloxacin was observed in 16 percent and 12 percent, respectively. Overall, 44 of the 50 isolates were classified as MDR, and one isolate was extensively drug-resistant (XDR).

Majority of Enterococcus Isolates Formed Biofilms

Biofilm formation was observed in 68 percent of E. faecalis and E. faecium isolates. Moderate biofilm formers accounted for 38 percent of total isolates, while 22 percent were weak producers and 8 percent were strong producers. The remaining 32 percent did not form biofilms.

The researchers noted that biofilm formation could contribute to the persistence of Enterococcus spp. in food processing environments. Biofilms can enhance bacterial survival under adverse conditions and may facilitate horizontal transfer of AMR and virulence genes.

Genetic Relatedness Suggests Potential Food–Human Interface

Using random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR), the researchers assessed genetic relatedness among the isolates gathered from meat, workers, and consumers. Five major clusters and five distinct RAPD profiles were observed. Isolates from meat, retail workers, and consumers were interspersed within the same clusters and profiles, which the researchers said indicated genetic relatedness among isolates from different sources and suggested the possibility of cross-transmission at the food-human interface.

However, the authors emphasized that the findings did not establish direct transmission. The study used convenience sampling, had a relatively small number of isolates, and employed a cross-sectional design. The researchers stated that higher-resolution approaches, such as whole genome sequencing (WGS), would be necessary to confirm transmission dynamics in future studies.

The researchers concluded that the co-occurrence of MDR, virulence determinants, biofilm formation, and genetic relatedness across food and human isolates supports the importance of monitoring Enterococcus spp. from a One Health perspective. They recommended improved hygiene during meat handling, particularly hand hygiene among workers, as well as routine AMR monitoring in food-producing animals and retail meat.