October 22, 2019

Study finds antibiotic-free poultry unlikely to contain multidrug-resistant Salmonella

Conventional poultry harboured two times more multidrug-resistant Salmonella compared to antibiotic-free poultry, reported the Centre for Infectious Disease Research and Policy.

The study was reported at IDWeek 2019 and conducted by scientists from the Pennsylvania Department of Health, Penn State College of Medicine, and the Food and Drug Administration (FDA).

For this study, 3,500 samples of chicken and turkey were purchased randomly from Pennsylvania stores between 2008 to 2017.

Non-typhoidal Salmonella cultures were examined, and analysis found that 55% of those from conventionally-raised poultry meat were resistant to three or more antibiotic classes, compared to 28% of the cultures from the antibiotic-free poultry meat.

More than 1.2 billion Americans are affected by Salmonella-caused foodborne illness every year. Some cases of salmonellosis require antibiotics and hospital treatment. Salmonella resistant to drugs are harder to treat and can cause severe or sometimes deadly infections.

The National Antibiotic Resistance Monitoring System programme was used to track antibiotic resistance in Salmonella and other commonly transmitted harmful bacteria.

Poultry that was labelled "organic", "antibiotic-free" or "no antibiotics ever" was considered "antibiotic-free" for the study.

Poultry was used as the focus of the study as Americans eat a lot of chicken­—the projected consumption of poultry meat in the US is around 50 kg per capita. Poultry is also a vital channel for the transmission of drug-resistant bacteria that cause gastrointestinal illness.

In another related study by a number of scientists from the same team, close to a third of Salmonella cultures from ground beef, pork and poultry samples purchased randomly from stores in Pennsylvania between 2015 to 2017 were found to be resistant to three or more antibiotic classes. The team also studied samples from human Salmonella infections in same period and found that a quarter of the Salmonella cultures were resistant to three or more antibiotic classes.

- Centre for Infectious Disease Research and Policy