Rare infection linked to consumption of raw dairy products

Scientists in India have reported a rare case of infection in a woman who consumed unpasteurized dairy products before falling sick.

Lactococcus lactis cremoris, previously known as Streptococcus lactis, is rarely reported as a cause of human infections. It is widely used in the production of fermented products in the dairy industry. As it lives on the skin of cattle, it is thought to contaminate milk.

Bacteria used in food preparation are commonly killed during digestion. However, Lactococcus remains viable even after going through the gastrointestinal tract.

The study, published in Cureus, a Springer Nature journal, details a probable case of food poisoning caused by Lactococcus lactis cremoris in an adult woman. A 58-year-old female was taken to an emergency room with a history of sudden onset of high-grade fever, vomiting, seizures, and loss of consciousness.

Link to raw milk products
Researchers from the Maharishi Markandeshwar Institute of Medical Sciences and Research in Ambala, India, said that Lactococcus lactis cremoris was isolated from her blood culture. The patient’s history included travel to a local pilgrimage and consumption of unpasteurized dairy products leading up to the incident.

A detailed history was taken from a family member to understand the source of infection. The patient had gone on a pilgrimage, during which she was consuming outside food, dairy products, and water. Though uncertain, the consumption of unpasteurized milk or dairy products could be the source of infection in this case, said scientists.

There are no standard guidelines for the treatment of Lactococcus lactis infection but she was given intravenous doxycycline and recovered after seven days of treatment with sterile blood cultures on follow-up.

Researchers said as the source of infection, risk factors, clinical presentation, and antibiotic sensitivity of Lactococcus lactis cases are relatively sparse, documentation of such events is essential to gather more relevant information.

“Though Lactococcus lactis was formerly known to be non-pathogenic, it has been the etiological agent for several human infections. In a patient with a history of consumption of unpasteurized dairy products, it is essential for the clinician to rule out a Lactococcus lactis infection,” they added.

Another study, published in the Journal of Medical Case reports in 2023, detailed the case of a 56-year-old Moroccan man who was admitted to hospital with a Lactococcus-associated liver abscess and endocarditis. The consumption of unpasteurized milk was reported.

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