A 60-year-old-man without a history of diabetes mellitus, or invasive manipulation or obstruction of the urinary tract was admitted for septic shock. Type I emphysematous pyelonephritis was clear in this case: gas within the renal parenchyma extending into the subcapsular region and the perirenal space was present on spiral computerised tomography (CT). Surgical nephrectomy was performed because biochemistry, urography and CT identified a damaged non-functioning left kidney. The outcome was favourable. All urine, blood and nephrectomy specimen cultures were positive for a specific Escherichia coli which produced a high level of gas compared to a reference E. coli strain in the same standard medium, despite the absence of diabetes mellitus. Certain strains of bacteria are able to produce high levels of nitrogen, carbon dioxide and hydrogen and such fermentation in the absence of a high glucose serum level might explain the acute gas-producing bacterial renal infection.