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

• Main Authors: Márió Gajdács, Zoltán Bátori, Marianna Ábrók, Andrea Lázár, Katalin Burián
• Format: Article
• Language: English
• Published: MDPI AG 2020-02-01
• Series: Life
• Subjects: clinical microbiology; indicators; urinary tract infection; gram-negative; drug resistance; usual drug resistance; difficult-to-treat resistance; udr; dtr; mdr; xdr; pdr
• Online Access: https://www.mdpi.com/2075-1729/10/2/16

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&#8722;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. <i>Citrobacter-Enterobacter-Serratia</i> had the highest level of UDR isolates (88.9%), the <i>Proteus-Providencia-Morganella</i> group had the highest mDTR levels. MDR levels were highest in <i>Acinetobacter</i> spp. (9.7%) and <i>Proteus-Providencia-Morganella</i> (9.1%). XDR- and DTR-levels were higher in non-fermenters (XDR: 1.7%&#8722;4.7%. DTR: 7.3%&#8722;7.9%) than in <i>Enterobacterales</i> isolates (XDR: 0%&#8722;0.1%. DTR: 0.02%&#8722;1.5%). Conclusions: The introduction of DTR (and its&#8217; 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.