Febrile
urinary tract infections (UTIs) often require the
intravenous infusion of
antibiotics and/or hospitalization. Acute
pyelonephritis (AP) is one of the most severe forms of UTI, and the
antibiotics we should use as the first line and the risk factors for treatment failure remain controversial. The objective of this study was to investigate the efficacy of i.v.
antibiotics selected for the treatment of febrile AP and to examine the risk factors for antibiotic resistance. We set risk factors for
antibiotic treatment failure such as age, sex, and the presence of underlying
urinary tract disease. We classified all cases into 49 cases of complicated AP and 24 cases of uncomplicated AP according to the presence of underlying
urinary tract diseases, and examined the characteristics of the patients and the efficacy of the
antibiotics used in this study. We investigated risk factors which relate to initial treatment failure and the duration of
antibiotic treatment. Initial
antibiotic treatment failure was significantly correlated to
C-reactive protein in complicated AP and to positive blood culture in uncomplicated AP. We revealed a significant correlation between the duration of the given
antibiotics and
diabetes mellitus or positive blood culture in uncomplicated AP, and
tazobactam/piperacillin was significantly related to prolongation of
antibiotic treatment in complicated AP. In conclusion, in this study, a positive blood culture was the representative risk factor that related to both initial treatment failure and longer duration of the given
antibiotics in uncomplicated AP.