Surveillance of ESBL-producers causing UTIs over a 6 year period

Abstract

Background: Urinary tract infections (UTIs) are one of the most prevalent community-acquired infections. ESBL-producing microorganisms are a growing threat to public health, and their presence among the community is spreading. The aim of this study was to access the prevalence of ESBL-producing isolates collected from urine of elderly attending the Emergency Room (ER) during a 6 year period (2011-2016). Methods & Materials: Bacterial strains were isolated from patients with primary diagnose UTI, older than 65 years, in the ER between 2011 and 2016. The Vitek2 system (according to EUCAST 2014 guidelines) and Advanced Expert System (BioM~rieux, Marcy L'toile, France) were used to identify and perform the antibiotic susceptibility profile of the isolates. ESBL production was confirmed using the Etest(r) (AB Biodisk) method, according to the manufacturer instructions. Results: 2925 samples were collected following the criteria listed above. The percentage of Escherichia coli isolates has been increasing since 2011, up to 51,7% in 2016, and the percentage of Klebsiella pneumoniae, which in 2011 was higher than E. coli, has been significantly decreasing in the last years, to around 15%. A reduction in the percentage of ESBL-producers until 2013 was noted, from where there has been an increase, both among E. coli and K. pneumoniae. In 2011, 82,5% of K. pneumoniae were ESBL-producers, and progressively decreases until 2015 to 32,5%. But a slightly increase in 2014 and 2016 (44,1% and 51,2%) shows the tendency of ESBL-producing K. pneumoniae spread in the community. E. coli ESBL-producers have also progressively diminished until 2013, then exhibiting an increase up to 24,0% in 2016. Conclusion: Considering the criteria used, we can conclude that they are carried by the patients who attend the ER repeatedly, thus spread in the community. Despite ESBL-producers have been significantly reduced in the last years, results show a possible increasing tendency. The same is observed both for E. coli and K. pneumoniae isolates, where the decrease in ESBL-producers until 2013 is now being overcome by higher percentages. Nevertheless, 2016 numbers are still high, being a motive of concern especially considering the elderly population.