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.