Characterization of Resistance in Gram-Negative Urinary Isolates Using Existing and Novel Indicators of Clinical Relevance: A 10-Year Data Analysis

Márió Gajdács; Zoltán Bátori; Marianna Ábrók; Andrea Lázár; Katalin Burián

doi:10.3390/life10020016

Characterization of Resistance in Gram-Negative Urinary Isolates Using Existing and Novel Indicators of Clinical Relevance: A 10-Year Data Analysis

Life (Basel). 2020 Feb 11;10(2):16. doi: 10.3390/life10020016.

Authors

Márió Gajdács¹, Zoltán Bátori², Marianna Ábrók³, Andrea Lázár³, Katalin Burián^{3

4}

Affiliations

¹ Department of Pharmacodynamics and Biopharmacy, Faculty of Pharmacy, University of Szeged, 6720 Szeged, Eötvös utca 6., Hungary.
² Department of Ecology, Faculty of Sciences, University of Szeged, 6726 Szeged, Közép fasor 52., Hungary.
³ Institute of Clinical Microbiology, Faculty of Medicine, University of Szeged, 6725 Szeged, Semmelweis utca 6., Hungary.
⁴ Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, 6720 Szeged, Dóm tér 10., Hungary.

Abstract

Classical resistance classifications (multidrug resistance [MDR], extensive drug resistance [XDR], pan-drug resistance [PDR]) are very useful for epidemiological purposes, however, they may not correlate well with clinical outcomes, therefore, several novel classification criteria (e.g., usual drug resistance [UDR], difficult-to-treat resistance [DTR]) were introduced for Gram-negative bacteria in recent years. Microbiological and resistance data was collected for urinary tract infections (UTIs) retrospectively, corresponding to the 2008.01.01-2017.12.31. period. Isolates were classified into various resistance categories (wild type/susceptible, UDR, MDR, XDR, DTR and PDR), in addition, two new indicators (modified DTR; mDTR and mcDTR) and a predictive composite score (pMAR) were introduced. Results: n = 16,240 (76.8%) outpatient and n = 13,386 (69.3%) inpatient UTI isolates were relevant to our analysis. Citrobacter-Enterobacter-Serratia had the highest level of UDR isolates (88.9%), the Proteus-Providencia-Morganella group had the highest mDTR levels. MDR levels were highest in Acinetobacter spp. (9.7%) and Proteus-Providencia-Morganella (9.1%). XDR- and DTR-levels were higher in non-fermenters (XDR: 1.7%-4.7%. DTR: 7.3%-7.9%) than in Enterobacterales isolates (XDR: 0%-0.1%. DTR: 0.02%-1.5%). Conclusions: The introduction of DTR (and its' modifications detailed in this study) to the bedside and in clinical practice will definitely lead to substantial benefits in the assessment of the significance of bacterial resistance in human therapeutics.

Keywords: DTR; Gram-negative; MDR; PDR; UDR; XDR; clinical microbiology; difficult-to-treat resistance; drug resistance; indicators; urinary tract infection; usual drug resistance.