What is the prognosis of emphysematous pyelonephritis associated with extended-spectrum beta-lactamases producing microorganisms?

To describe the microbiological characteristics in emphysematous pyelonephritis (EPN), demonstrate the frequency of extended-spectrum beta-lactamase (ESBL) microorganisms, and determine if these microorganisms are associated with the prognosis of patients with EPN.

We conducted a retrospective study in patients with a diagnosis of EPN in a tertiary care hospital of the northeast region of Mexico during the period from January 2011 to January 2016. Clinical variables were analyzed to determine association with the presence of ESBL-producing microorganisms. Statistical significance was set with p<0.05.

A total of 63 patients were included; 55 (87.3%) of them were females, with a median age of 55 (interquartile range: 45-65) years. Conservative management was indicated in 38.1%; 42.9% were treated with ureteral stent; 12.7% with open or percutaneous drainage; 15.8% with early nephrectomy; and 9.5% with delayed nephrectomy. Reported mortality was 13 (20.6%) cases; 23 (36.5%) cases required admission to the intensive care unit. The most frequent microorganism isolated was Escherichia coli (n=34, 53.9%). ESBL microorganisms were found in 31.7% of the population. No significant association of ESBL was found with admission to the intensive care unit, or with increased mortality.

To our knowledge, this is the first study that evaluates ESBL microorganisms as a prognostic factor in EPN. Risk factors associated with a poor prognosis in patients with EPN have been described. The microbiological factors, specifically ESBL-producing bacteria, do not seem to influence in the prognosis of these patients.