Epidemic glomerulonephritis due to Streptococcus zooepidemicus in Nova Serrana, Brazil

Abstract

Background. In 1998, there was a large outbreak of acute glomerulonephritis in Nova Serrana, Brazil, caused by group C Streptococcus zooepidemicus. This article reviews the characteristics of the outbreak and some aspects of the patients' follow-up. Methods. We describe clinical characteristics of patients with acute nephritis. Using case-control studies, we identified the source of infection. Cultures of oropharyngeal swabs from patients were performed. Of 135 patients identified in 1998, available patients were reexamined in a prospective study after 2 and 5 years. Results. Lancefield group C S. zooepidemicus was identified as the causative organism and linked to the consumption of cheese produced from unpasteurized milk. Of the original group of 134 patients, 4 died in the acute phase and 5 (3.7%) required chronic dialysis. After 2 years, of the 69 cases reevaluated, 94% were adults (mean ± standard error age: 39 ± 2 years); we found arterial hypertension in 42% (N = 27/64) of the patients, reduced creatinine clearance (<80 mL/min/1.73 m2) in 30% (N = 20/67), and increased microalbuminuria (>20 μg/min) in 34% (N = 22/65). Preliminary data at 5-year follow-up suggest that the percentage of patients with creatinine clearance lower than 60 mL/min increased from 9% to 15%. Conclusion. This article highlights the dangers of consuming unpasteurized dairy products. Follow-up of patients with epidemic poststreptococcal glomerulonephritis due to S. zooepidemicus show that a considerable proportion present hypertension, reduced renal function, and increased microalbuminuria. © 2005 by the International Society of Nephrology.