Assessment of performance and comparison of three commercial HDV RNA detection assays: implications for diagnosis and treatment monitoring.

Objectives: Precise HDV-RNA detection and quantification are pivotal for diagnosis and monitoring of response to newly approved treatment. We evaluate the performance of three HDV RNA detection and quantification assays. Methods: Hepatitis Delta RT-PCR system kit, EurobioPlex HDV assay, and RoboGene HDV RNA Quantification kit 2.0 were used for testing 151 HBsAg-positive samples, 90 HDV-RNA negative and 61 HDV-RNA positive. We also evaluated serial dilutions of the WHO international standard for HDV, PEI 7657/12. All HDV-RNA positive samples were genotyped using a next-generation sequencing strategy. Results: Qualitative results indicated a 100% concordance between tests. Quantitative results correlated well, r2 = 0.703 (Vircell-vs-Eurobio), r2 = 0.833 (Vircell-vs-RoboGene), r2 = 0.835 (Robogene-vs-Eurobio). Bias index was 2.083 (Vircell-vs-Eurobio), -1.283 (Vircell-vs-RoboGene), and -3.36 (Robogene-vs-Eurobio). Using the WHO IS, Vircell overestimated the viral load by 0.98 log IU/mL, Eurobio by 1.46 log IU/mL, and RoboGene underestimated it by 0.98 log IU/mL. Fifty-nine samples were successfully genotyped (Genotype 1, n=52; Genotype 5, n=7; Genotype 6, n=1), with similar results for correlation and bias. Conclusion: This study underscores the necessity of using reliable HDV-RNA detection and quantification assays, as evidenced by the high concordance rates in qualitative detection and the observed variability in quantitative results. These findings highlight the importance of consistent assay use in clinical practice to ensure accurate diagnosis and effective treatment monitoring of HDV infection.

Characterization of NDM-1- and CMH-3-producing Enterobacter cloacae complex ST932 in a patient transferred from Ukraine to Spain.

INTRODUCTION: To characterize a carbapenem-resistant Enterobacter cloacae complex isolate recovered from a patient from Ukraine. METHODS: The isolate was sent to a regional reference laboratory for molecular characterization by whole genome sequencing. Susceptibility assays, carbapenemase identification, imipenem hydrolysis and clonality were performed. RESULTS: The isolate showed resistance or reduced susceptibility to all ß-lactam agents tested. Genome analysis led to the identification of an NDM-1-producing E. cloacae complex strain that was assigned to a new multilocus sequence type, ST932. The blaNDM-1 enzyme was located in a conjugative IncX3 plasmid of ca. 50kb. In addition, blaCMH-3, a recently described AmpC ß-lactamase sequence, which has not previously been reported in Europe, was also detected and its genetic environment was studied. CONCLUSION: To our knowledge, this is the first reported case in Europe of an E. cloacae complex strain that produces both blaNDM-1 and blaCMH-3.