Resistencia de Escherichia coli a quinolonas y factores asociados en pacientes hospitalizados por pielonefritis aguda

Résumé

Introduction. Acute pyelonephritis (APN) is an infection of the renal parenchyma that most often affects women. Despite the fact that it is a usually benign pathology, complications can occur, some serious, it has a high prevalence and involves a large consumption of both healthcare and financial resources. They are usually produced by enterobacteria, fundamentally, Escherichia coli (E. coli) is the main isolated microorganism. In recent years, the indiscriminate use of quinolones has led to a marked increase in resistance, and cephalosporins have emerged as one of the main alternatives. Objectives. Analyze the resistance of E. coli to quinolones and cephalosporins and identify associated risk factors. Study the main causes of readmission and reinfection. Define criteria for poor prognosis and poor evolution, and check their prevalence. Creation of a model to predict resistance of E. coli to quinolones and poor prognosis. Methods. Observational, retrospective and descriptive study with analytical components of a cohort of patients admitted with the diagnosis of APN over two years at the Virgen de la Arrixaca University Clinical Hospital. Epidemiological, analytical, clinical and microbiological data were included. The SPSS program was used for the statistical analysis and predictive models was created with the R-project. Results. The sample consisted of 404 patients, of which 87.1% were women, with an average age of 42.7 years. Fever was the most frequent symptom. An average hospitalization of 5.7 days was observed and most patients were treated at the Short Stay Unit (SSU) (42.6%). 234 urine cultures (60.3%) were positive; in 177 E. coli (75.7%) was isolated. The resistance of E. coli to quinolones was 18.8% and 7.4% to cephalosporins. Among the risk factors, males stood out for resistance to quinolones and urinary surgery for cephalosporins. The reinfection and readmission rates were 21.8% and 16.3%, respectively. Reinfection was mainly associated with previous urinary infections, while readmission was required mostly in patients with renal diseases. 28.2% of the patients had a poor evolution and 49% had a poor prognosis; a recent admission and a high Charlson index were associated with poor evolution, and resistance to quinolones and bacteremia in the case of poor prognosis; treatment with cephalosporins, nevertheless, was shown to be a protective factor. Conclusions. E. coli remains the main germ responsible for APN. Currently, the resistance of E. coli to quinolones and cephalosporins in our environment is in decline, below the national and European average, although in the first case it continues to be higher than other countries with a similar social and health development level. However, the use of quinolones should continue to be avoided, especially in men; cephalosporins are an adequate empirical treatment for APN, with the exception of patients previously submitted to urological surgeries. With the predictive models created, a 60% probability of resistance of E. coli to quinolones and a 90% of poor prognosis has been calculated in patients who meet the three conditions considered: male sex, admission in the previous two months and high Charlson index. Keywords: Pyelonephritis. Urinary tract infections. Escherichia coli. Quinolones.