An outbreak of Streptococcus equi subspecies zooepidemicusassociated with consumption of fresh goat cheese

Abstract

BackgroundStreptococcus equi subspecies zooepidemicus is a rare infection in humans associated with contact with horses or consumption of unpasteurized milk products. On October 23, 2003, the National Public Health Institute was alerted that within one week three persons had been admitted to Tampere University Central Hospital (TaYS) because of S. equi subsp. zooepidemicus septicaemia. All had consumed fresh goat cheese produced in a small-scale dairy located on a farm. We conducted an investigation to determine the source and the extent of the outbreak.MethodsCases were identified from the National Infectious Disease Register. Cases were persons with S. equi subsp. zooepidemicus isolated from a normally sterile site who had illness onset 15.9-31.10.2003. All cases were telephone interviewed by using a standard questionnaire and clinical information was extracted from patient charts. Environmental and food specimens included throat swabs from two persons working in the dairy, milk from goats and raw milk tank, cheeses made of unpasteurized milk, vaginal samples of goats, and borehole well water. The isolates were characterized by ribotyping and pulsed-field gel electrophoresis (PFGE).ResultsSeven persons met the case definition; six had septicaemia and one had purulent arthritis. Five were women; the median age was 70 years (range 54–93). None of the cases were immunocompromized and none died. Six cases were identified in TaYS, and one in another university hospital in southern Finland. All had eaten goat cheese produced on the implicated farm. S. equi subsp. zooepidemicus was isolated from throat swabs, fresh goat cheese, milk tank, and vaginal samples of one goat. All human and environmental strains were indistinguishable by ribotyping and PFGE.ConclusionThe outbreak was caused by goat cheese produced from unpasteurized milk. Outbreaks caused by S. equi subsp. zooepidemicus may not be detected if streptococcal strains are only typed to the group level. S. equi subsp. zooepidemicus may be a re-emerging disease if unpasteurized milk is increasingly used for food production. Facilities using unpasteurized milk should be carefully monitored to prevent this type of outbreaks.

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“…During the study period there was an outbreak caused by S. equi subspecies zooepidemicus associated with consumption of unpasteurized goat cheese in 2003 (6 cases). 15 Positive blood cultures were obtained from 309 patients. Six patients had a recurrent beta-hemolytic bacteremia, two of them recurrent GBS and four GGS bacteremias.…”

Streptococcus equi Primary Bacteremia in a Hepatitis-C Cirrhotic Patient

“…equi, and S. equi subsp. zooepidemicus have been reported in outbreaks of food borne diseases or prior exposure to animals (5,6). In this case, the source of patient's infection was most likely his occupational exposure as a donkey breeder.…”

Prosthetic Valve Endocarditis and Disseminated Infection Caused by Streptococcus equi

“…zooepidemicus nadir olsa da insanlarda ağır seyirli, çok odaklı hastalığa neden olabilmektedir (1)(2)(3)(4)(5). Hayvanlarla temas sonrası genellikle sporadik olgular, çiğ veya pastörize edilmemiş süt ve süt ürünleri tüketimiyle ise salgınlar bildirilmiştir (1)(2)(3). Ülkemizde grup C streptokok infeksiyonu bildirimi oldukça sınırlıdır.…”