Researchers said Klebsiella pneumoniae is thought of an organism that is carried naturally, or acquired from the environment but the work shows it can be picked up in food.
To better understand potential contributions of foodborne K. pneumoniae to human clinical infections, the work compared isolates from retail meat products and human clinical specimens to assess similarity based on antibiotic resistance, genetic relatedness, and virulence.
In humans, K. pneumoniae frequently colonizes the gut and sporadically causes infections.
Isolation from retail meats
It was isolated from retail meats such as chicken, turkey and pork from Flagstaff grocery stores in 2012 and from urine and blood specimens from Flagstaff Medical Center in 2011–2012.
Isolates underwent antibiotic susceptibility testing and whole-genome sequencing. Genetic relatedness of the isolates was assessed using multilocus sequence typing and phylogenetic analyses.
Meat-source isolates were more likely to be multidrug resistant and resistant to tetracycline and gentamicin than clinical isolates.
Agricultural operations give food animals antibiotics to make them grow faster and prevent diseases, which can create conditions ideal for resistant strains of Klebsiella, according to the study.
The team found Klebsiella isolated from retail meat products with that isolated from patients and found that some isolate pairs were nearly identical.
They looked at turkey, chicken and pork products sold in nine grocery stores in Flagstaff, Arizona, in 2012.
Then they analyzed urine and blood samples from Flagstaff area residents suffering from infections during the same time period.
Klebsiella findings
Lance Price, lead author and a professor of environmental and occupational health at Milken Institute School of Public Health (Milken Institute SPH) at the George Washington University, said it was the first study to suggest consumers could be exposed to Klebseilla from contaminated meat.
“The US government monitors food for only a limited number of bacterial species, but this study shows that focusing on the ‘usual suspects’ may not capture the full scope of foodborne pathogens.”
Price and colleagues found 47% of the 508 meat products purchased from grocery stores harbored Klebsiella and many of the strains were resistant to antibiotics.
Meat product contamination varied significantly by meat type: 58% (65 of 112 samples) for pork, 47% (128/272) for chicken, and 38% (48/128) for turkey.
A subset of 82 K. pneumoniae isolates was randomly chosen for WGS, including 38 clinical and 44 meat-source isolates.
“Here we show that retail meat may be an important source of antibiotic-resistant K. pneumoniae of possible human health significance, which increases the range of potential public health risks associated with antibiotic use in food-animal production,” found the study.
Researchers said the food safety system has focused on a few well-known bacteria like Listeria, Salmonella and Campylobacter but their findings suggest Klebsiella may need to be added to the list.
Financial and material support was provided by the Department of Defense Telemedicine and Advanced Technology Research Center.
Source: Clinical Infectious Diseases
Online ahead of print, DOI: 10.1093/cid/civ428
“Intermingled Klebsiella pneumoniae Populations Between Retail Meats and Human Urinary Tract Infections”
Authors: Gregg S. Davis, Kara Waits, Lora Nordstrom, Brett Weaver, Maliha Aziz, Lori Gauld, Heidi Grande, Rick Bigler, Joseph Horwinski, Stephen Porter, Marc Stegger, James R. Johnson, Cindy M. Liu and Lance B. Price