Poultry found resistant to antibiotics; study warns risks in consumption

MANILA, Philippines — A study from Cavite State University warns about the misuse of antibiotics on poultry, after batches of farm chickens in the province became resistant to antimicrobial medication, which raises the risk of disease transmission to humans.

Bacterial diseases among the chickens were found prevalent in certain farms in Barangay Tambo Malaki, Indang town, and in Barangay Litlit, Silang town, according to the study by veterinarian and microbiologist Cynthia Rundina-Dela Cruz.

Titled “Antibiotic Sensitivity Profile and Dominant Antibiotic Resistance Genes in Selected Avian Bacterial Pathogens from Commercial Poultry Farms in Upland Cavite,” the study was presented on Oct. 2 at a symposium by the Department of Science and Technology (DOST) on agriculture and aquatic and natural resources research and development.

READ: To keep our antibiotics working

Indiscriminate use

The broiler chickens examined were found to have developed antimicrobial resistance (AMR) to at least eight antibiotics—one of them classified by the World Health Organization (WHO) as a “last resort” medication.

AMR, considered one of the world’s top public health concerns, occurs when bacteria, viruses, and fungi are no longer sensitive to medication—leading to the spread of a disease and making treatment difficult, according to the WHO.

One primary driver of AMR is the indiscriminate use of antibiotics on humans and even animals and plants.

Dela Cruz noted in her study that “chicken farmers in the Southeast Asian region commonly misuse and overuse antibiotics.”

In upland Cavite, the study learned, the prevalence of avian pathogenic Escherichia coli (Apec) was at 25.6 percent in Tambo Malaki, while the incidence of S. enterica, a species of Salmonella, was at 58.9 percent.

The infected chickens were found to be resistant to the following antibiotics: azithromycin (53.8 percent); cephalotin and trimethoprim-sulfamethoxazole or TMPS (both at 40 percent); tetracycline (23 percent); amoxicillin-clavulanic acid (23 percent); and ciprofloxacin, doxycycline and kanamycin (each at 15.3 percent).

These findings meant that the farms haphazardly used Colistin—identified as the “last resort” medication—as well as TMPS, which is used to treat salmonellosis, said Dela Cruz, dean of the College of Veterinary Medicine at the university.

She also noted that “biosecurity protocols were not strictly employed” in the farms—such as the assistance of resident veterinarians who could provide guidance on antibiotic intake and the provision of shower facilities, vehicle baths and perimeter gates.

Other animals, such as dogs, cats, birds and goats—all potential pathogen carriers—were also roaming around the farms, increasing the chances of a rapid spread of disease.

Food security

In a forum in November last year marking World Antimicrobial Resistance Awareness Week, the Department of Health called on the agriculture sector to avoid using antibiotics as “growth promoters” among livestock, as this contributes to AMR, threatening not only public health but food security.

Pharmacist Johanna Mallari-Abella, who is also the research head of the department’s pharmaceutical division, had cautioned that antimicrobial residues stay in the meat, making it unfit for human consumption.

Even vegetables contaminated with drug-resistant bacteria pose a health risk, the Philippine College of Physicians warned last year, saying that consumption may also lead to the development of AMR.

In a recent online forum, infectious diseases specialist Maria Yvette Barez said “AMR superbugs” remain in infected animals and in the “organic fertilizer in our vegetables.”

She warned that these “resistant bugs” are projected to cause the deaths of more than 10 million people by 2050, and called for the observance of hygiene in the handling of meat and vegetables.

“When not properly cleaned or washed, it stays in the [food] we eat, and so we get the resistant bugs,” she said.