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

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.

Antibiotic Resistance, Virulence Factors, Phenotyping, and Genotyping of Non-Escherichia coli Enterobacterales from the Gut Microbiota of Healthy Subjects

“…The link between colonization and infection by K. pneumoniae in hospitalized patients has been demonstrated, with robust evidence that their own microbiota is the main source of the infective strains [35,36]. Thus, potentially more virulent K. pneumoniae strains may take advantage of critical conditions, becoming responsible for nosocomial infections [37].…”

<p>Clinical Characteristics and Risk Factors for Bloodstream Infection Due to Carbapenem-Resistant <em>Klebsiella pneumoniae</em> in Patients with Hematologic Malignancies</p>

“…6,11,15,16 Novel resistance classifications for Gram-negative bacteria suggested that an extended-spectrum β-lactamase (ESBL)-producing, carbapenem-resistant and fluoroquinolone-resistant isolate was considered as difficultto-treat resistance (DTR). 17 Infections, especially bloodstream infections caused by CRKP can cause significantly high mortality, for the reason that it expresses multidrug resistance phenotypes so that antimicrobial treatments appear to be quite intractable. In our study, the 28-day mortality of CRKP BSI among patients with hematologic malignancies reached 77.3%.…”

Revival of older antibiotics for the therapy of urinary tract infections: old, but gold Part 1: Antimicrobial susceptibility of extended-spectrum β-lactamase-producing and AmpC β-lactamase-producing Escherichia coli isolates

“…Due to their transmissibility, ESBLs are considered a serious public health/infection control issue, especially because these enzymes are encoded on larger-sized plasmids [18,30,34]. As several resistancedeterminants are often present in bacteria simultaneously, in addition to b-lactams, other antibiotic-groups may be affected, rapidly resulting in MDR, or even XDR strains, with severely limited therapeutic options left [26,35]. These isolates have been associated with increased morbidity and mortality, particularly in ICUs and in severely immunocompromised patients [36].…”