Microbiological Spectrum and Outcomes of Acute Pyelonephritis in North Indian Population

A wide range of causative organisms can cause acute pyelonephritis (APN). However, in recent times, these pathogens have increasingly become resistant to most of the antibiotics making treatment difficult. This was a prospective observational single-center study with a aim to study the microbiological spectrum, resistance patterns, and clinical outcome of patients with APN conducted in a private tertiary care hospital in India. All adult patients hospitalized in the department of nephrology at our institute with a diagnosis of APN from February 2016 to May 2017 were included. Patients <18 years of age, kidney-transplant recipients, and pregnant patients were excluded. Demographic details, clinical symptoms, signs, and radiological and laboratory data including urine and blood cultures of all patients were recorded. The details of treatment received and outcomes in hospital and after discharge were noted. Patients were followed up three months post discharge. Decision of antibiotic and duration of antibiotics was documented by treating nephrologists. Quantitative data were presented in terms of means and standard deviation. Student's "t" test was used for comparison of quantitative outcome parameters. P <0.05 is considered statistically significant. SPSS software version 23.0 was used for statistical analysis. A total of 89 patients with a mean age of 50.33 ± 13.9 years, of which 61.8% were males and were studied; 82/89 had complicated pyelonephritis. The most common risk factor for APN was diabetes mellitus in 64 (72%). Most common symptom was fever in 80 (90%). A triad of fever, flank pain, and dysuria was present only in 27 (30.33%). Overall, 15 patients (16.8%) had severe pyelonephritis requiring intensive care unit admission. The most common organism isolated was Escherichia coli in 26/49 (53%), followed by Klebsiella pneumoniae in 12 (24.40%). Twenty-two (58%) isolates were extended-spectrum beta lactamase producers. Six (12.20%) were resistant to carbapenems and two (4%) were pan-resistant. All 89 were treated with intravenous antibiotics. Older patients, those with diabetes, with poor glycemic control, and with emphysematous pyelonephritis and patients in whom ESBL organisms were grown had poor outcome. Piperacillin tazobactam, aminopenicillins, cefoperazone sulbactam, and carbapenems (in severe pyelonephritis) can be considered as the empirical antibiotic of choice.