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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.