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Anaphylactic reaction linked to fruit antibiotic

A Canadian pediatric patient experienced an anaphylactic reaction after eating blueberry pie, which researchers linked to streptomycin used as a food antibiotic, according to recent study results.

“As far as we know, this is the first report that links an allergic reaction to fruits treated with antibiotic pesticides,” researcher Anne Des Roches, MD, FRCP, associate professor of the pediatrics department, Montreal University, and head of the allergy section, Sainte-Justine Hospital, Montreal, said in a press release. “Certain European countries ban the use of antibiotics for growing foods, but the United States and Canada still allow them for agricultural purposes.”

Anne Des Roches

Des Roches and colleagues in Montreal studied the patient, aged 10 years, who presented with anaphylaxis after ingesting blueberry pie. She had a history of asthma and allergic rhinitis, with known anaphylaxis to penicillin and IgE-mediated cow’s milk allergy. She experienced facial flushing, urticaria and stridor within 10 minutes of consuming the pie. She was treated with epinephrine, methylprednisolone and diphenhydramine at an ED and kept overnight.

Skin tests taken at an allergy department for pie ingredients, including fresh blueberries and peels, eggs, soya, peanuts, nuts and cereal, were negative 5 weeks after initial reaction. There were 13-mm wheals as a result of skin tests to milk. Pie sample analyses revealed milk below the detection levels. The samples also contained non-B-lactam antibiotic; however, the lab was unable to confirm its identity because of an insufficient sample size.

Skin-prick testing with dilutions of streptomycin (400 mg/mL), commonly used in orchards to treat bacterial infections of fruit, were negative. Reactions to intradermal skin tests with dilutions of 1:100 (4 mg/mL) and 1:10,000 (0.04 mg/mL), however, resulted in the patient experiencing neck urticaria. She later developed inspiratory stridor and generalized urticaria. She had not been treated previously with streptomycin.

“Although we did not have enough of the original blueberry pie sample to perform streptomycin detection assays, the positive skin-prick test results, the systemic reaction of the cutaneous tests to streptomycin, and the presence of a non-B-lactam antibiotic in the analyzed sample suggested that a streptomycin-contaminated blueberry was responsible for the anaphylactic reaction,” the researchers reported.

James Sublett

“This is a rare allergic reaction,” James Sublett, MD, American College of Allergy, Asthma and Immunology president-elect, said in the release. “Nevertheless, it’s something allergists need to be aware of and that emergency room personnel may need to know about in order to help determine where anaphylactic reactions may arise.”

Disclosure: The researchers report no relevant financial disclosures.