Antibiotics are essential for both human and animal health,  supporting everything from routine surgeries to the treatment of infections. But when bacteria are repeatedly exposed to these drugs, some adapt and survive.  

These resistant strains can multiply, spread, and in some cases, transfer from farms to people through food, water or direct contact. To that end, monitoring these data in animals is a crucial preventive measure that can help public health teams identify resistant strains before outbreaks occur and inform policies that protect both consumers and farmers. 

In the paper “Genomic surveillance of antimicrobial resistance in bovine fecal samples from Lebanon,” Professor Sima Tokajian and Assistant Professor Charbel Al Khoury at the School of Arts and Sciences, partnered with a team that included Jame Tannous (BS ’22; MS ‘25), Sandra Haddad (BS ‘25), currently a medical student at LAU, and other Lebanon-based collaborators.

Published in Veterinary Microbiology, a journal featured in the prestigious ShanghaiRanking Academic Excellence Survey, the study set out to answer a practical question: Which antibiotic-resistant bacteria are present in cattle farms across Lebanon, and what do their genes reveal about how resistance spreads?  

Between January and November 2023, the team collected 35 fecal samples from 24 dairy farms across 18 regions, representing 175 cows. The process presented multiple challenges, noted Dr. Tokajian, including the absence of a national registry of dairy farms and convincing farmers to participate, most of whom were not familiar with antimicrobial resistance and initially skeptical of its relevance.

Getting to the farms, in itself, was a logistical hurdle, added Dr. Tokajian. “Lebanon’s geography meant long drives to remote areas, sometimes for a single sample, which is part of why fieldwork stretched across nearly a year,” she said.

After collecting the samples, the researchers isolated bacteria using a screening medium designed to flag strains that can break down certain antibiotics, tested the isolates against multiple antibiotics and used whole-genome sequencing— a reading of the bacteria’s complete DNA— to pinpoint resistance and other risk-related genes.  

The scale of resistance was striking. The team recovered 62 unique bacteria with an ESBL profile, indicating their ability to produce enzymes that deactivate several important antibiotics. Of these, 33 of 62 were multidrug-resistant.  

Escherichia coli (E. coli), a bacterium that can be harmless but can also cause serious infections, was the most common species, accounting for 37 of 62 isolates, which showed resistance to amoxicillin, ceftriaxone and cefotaxime, antibiotics used in veterinary and human care. About 76 percent of the E. coli isolates were classified as multidrug-resistant, highlighting how easily resistance can become dominant when antibiotics are used frequently.  

The most common resistance gene, bla_CTX-M-15, was  detected in 27 of 37 E. coli isolates,  suggesting that the resistance is not random, but  stems mainly from this gene. The team also found one E. coli isolate with resistance to colistin,  an antibiotic sometimes reserved for severe infections in humans.   

The study strengthens the case for an integrated “One Health” response between veterinary practice, food safety and public health to promote responsible antibiotic use and routine monitoring. It also contributes to increasing public education and awareness, which is only effective if farmers, vets, and healthcare workers understand how resistance moves between animals and people, said Dr. Tokajian.

She underscored the vital role the President’s Intramural Research Fund (PIRF) played in making the research possible, as it “not only funded reagents and sequencing but also made it feasible to reach those farms, build relationships with farming communities, and generate data that Lebanon genuinely needs,” she said.

To browse more scholarly output by the LAU community, visit our open-access digital archive, the Lebanese American University Repository (LAUR).