Long time persistence and evolution of carbapenemase-producing Enterobacterales in the wastewater of a tertiary care hospital in Germany

Carbapenem-Resistant NDM and OXA-48-like Producing K. pneumoniae: From Menacing Superbug to a Mundane Bacteria; A Retrospective Study in a Romanian Tertiary Hospital

BACKGROUND

Carbapenem-resistant Klebsiella pneumoniae (Cr-Kpn) is becoming a growing public health problem through the failure of adequate treatment. This study's objectives are to describe the sources of Cr-Kpn in our hospital over 22 months, associating factors with the outcome of Cr-Kpn-positive patients, especially those with NDM+OXA-48-like (New Delhi Metallo-β-Lactamase and oxacillinase-48), and the effectiveness of the treatments used.

METHODS

A retrospective observational cohort study including all hospitalized patients with Cr-Kpn isolates. We reported data as percentages and identified independent predictors for mortality over hospital time through multivariate analysis.

RESULTS

The main type of carbapenemases identified were NDM+OXA-48-like (49.4%). The statistical analysis identified that diabetes and co-infections with the Gram-negative, non-urinary sites of infection were factors of unfavorable evolution. The Cox regression model identified factors associated with a poor outcome: ICU admission (HR of 2.38), previous medical wards transition (HR of 4.69), and carbapenemase type NDM (HR of 5.98). We did not find the superiority of an antibiotic regimen, especially in the case of NDM+OXA-48-like.

CONCLUSIONS

The increase in the incidence of Cr-Kpn infections, especially with NDM+OXA-48-like pathogens, requires a paradigm shift in both the treatment of infected patients and the control of the spread of these pathogens, which calls for a change in public health policy regarding the use of antibiotics and the pursuit of a One Health approach.

High Genetic Diversity in Third-Generation Cephalosporin-Resistant Escherichia coli in Wastewater Systems of Schleswig-Holstein

The spread of multidrug-resistant bacteria from humans or livestock is a critical issue. However, the epidemiology of resistant pathogens across wastewater pathways is poorly understood. Therefore, we performed a detailed comparison of third-generation cephalosporin-resistant Escherichia coli (3GCREC) from wastewater treatment plants (WWTPs) to analyze dissemination pathways. A total of 172 3GCREC isolated from four WWTPs were characterized via whole genome sequencing. Clonal relatedness was determined using multi-locus sequence typing (MLST) and core genome MLST. Resistance genotypes and plasmid replicons were determined. A total of 68 MLST sequence types were observed with 28 closely related clusters. Resistance genes to eight antibiotic classes were detected. In fluoroquinolone-resistant isolates, resistance was associated with three-or-more point mutations in target genes. Typing revealed high genetic diversity with only a few clonal lineages present in all WWTPs. The distribution paths of individual lines could only be traced in exceptional cases with a lack of enrichment of certain lineages. Varying resistance genes and plasmids, as well as fluoroquinolone resistance-associated point mutations in individual isolates, further corroborated the high diversity of 3GCREC in WWTPs. In total, we observed high diversity of 3GCREC inside the tested WWTPs with proof of resistant strains being released into the environment even after treatment processes.

Dissemination of ESBL-producing E. coli ST131 through wastewater and environmental water in Switzerland

The E. coli lineage ST131 is a major cause of multidrug-resistant urinary tract and bloodstream infections worldwide. Recently emerged ST131 sublineages spread globally within few years, but their dissemination routes are incompletely understood. In this study, we investigate the potential role of wastewater and surface water in the spread of extended-spectrum β-lactamase (ESBL)-producing ST131. Streams, lakes, and two wastewater treatment plants (WWTPs) in the canton of Zug, Switzerland, were consecutively sampled over 1.5 years. ST131 was detected in 38% of the samples taken downstream (1-5 km) of WWTP discharge sites, but usually absent in water bodies distant from urban areas or WWTP discharge. Specific strains were repeatedly isolated (≤5 pairwise cgSNP distance) from wastewater or river sites downstream of effluent discharge, indicating their repeated entry or persistence in WWTPs in large concentrations. Genetic characterization of the ESBL-producing water isolates revealed a predominance of clades A and C1 and an emerging ciprofloxacin-resistant sublineage with mutations in quinolone resistance determining regions (QRDR) within clade A. Multiple isolates belonged to internationally circulating sublineages, including C1-M27 and papGII + sublineages with chromosomally encoded ESBLs. This study demonstrates that the clinically relevant E. coli lineage ST131 pollutes river ecosystems, representing a significant challenge to public health and to technologies to minimize their entry into the water environment.