Background/Aims: The aim of this study was to examine the recent clinical trends and antibiotic susceptibilities of the causative microorganisms in renal and perirenal abscesses, and to elucidate the factors associated with treatment strategies.Methods: We retrospectively analyzed 56 patients who were diagnosed with renal and perirenal abscesses at our hospital from January 2000 to September 2007.Results: The mean age of the patients was 53.5 years, and a female predominance of patients (75%) was observed. Diabetes mellitus (44.6%) was the most common predisposing condition. The mean duration of symptoms before diagnosis was 11.6 days, and fever (75%) was the most common symptom. Escherichia coli (44%) and Klebsiella pneumoniae (28%) were common pathogens, and the rates of susceptibility of E. coli isolates to ampicillin, cephalothin, cefotaxime, trimethoprim-sulfamethoxazole, ciprofloxacin, gentamicin, and imipenem were 18.2%, 27.3%, 72.7%, 72.7%, 63.6%, 63.6%, and 100%, respectively. Abscesses were classified according to the location as follows: renal abscess (n=31, 55.4%) and perirenal abscess±renal abscess (n=25, 44.6%). In the renal abscess group, the infection rate of gram-negative organisms was higher than in the perirenal abscess group. Patients were also divided according to the treatment modality: antibiotics only (n=20, 35.7%) and percutaneous intervention or surgery (n=36, 64.3%). Patients who had a perirenal abscess or a large renal abscess required more invasive treatment.Conclusions: This study revealed somewhat different results from those of previous studies. Clinical and microbial differences were observed between the renal and perirenal abscess groups. Abscess location and the size of the renal abscess were the factors associated with treatment strategies.
