Isolation of anaerobic organisms from kidney in serious renal infections

We have studied 45 patients who underwent nephrectomy owing to unilateral renal sepsis for anaerobic and aerobic bacterial growth in the urine and kidney. Anaerobic organisms were recovered from 11 patients: 10 had positive kidney cultures, and only 1 had positive kidney and urine cultures. There was a distinct relationship between anaerobic infection of the kidney and urinary tract obstruction; 44 per cent of the obstructed kidneys yielded anaerobic organisms versus only 11 per cent of the unobstructed kidneys. Bacteroides fragilis was the anaerobic organism most often cultured. It is suggested that cultures for anaerobic organisms be performed together with aerobic cultures in patients with symptomatic upper urinary tract infections associated with urinary obstruction. In patients in whom anaerobic infection is suspected, in spite of negative anaerobic cultures, antibiotic treatment for anaerobes should be added to the existing therapeutic measures.