RÉSUMÉ
Background The convergence of hypervirulence and carbapenem resistance in the bacterial pathogen Klebsiella pneumoniae represents a critical global health concern. Hypervirulent K. pneumoniae (hvKp) strains, frequently from sequence type 23 (ST23) and having a K1 capsule, have been associated with severe community-acquired invasive infections. Although hvKp were initially restricted to Southeast Asia and primarily antibiotic-sensitive, carbapenem-resistant hvKp infections are reported worldwide. Here, within the carbapenemase production Enterobacterales surveillance system headed by the Chilean Public Health Institute, we describe the isolation in Chile of a high-risk ST23 dual-carbapenemase-producing hvKp strain, which carbapenemase genes are encoded in a single conjugative plasmid. Results Phenotypic and molecular tests of this strain revealed an extensive resistance to at least 15 antibiotic classes and the production of KPC-2 and VIM-1 carbapenemases. Unexpectedly, this isolate lacked hypermucoviscosity, challenging this commonly used hvKp identification criteria. Complete genome sequencing and analysis confirmed the K1 capsular type, the KpVP-1 virulence plasmid, and the GIE492 and ICEKp10 genomic islands carrying virulence factors strongly associated with hvKp. Although this isolate belonged to the globally disseminated hvKp clonal group CG23-I, it is unique, as it formed a clade apart from a previously reported Chilean ST23 hvKp isolate and acquired an IncN KPC-2 plasmid highly disseminated in South America (absent in other hvKp genomes), but now including a class-I integron carrying blaVIM−1 and other resistance genes. Notably, this isolate was able to conjugate the double carbapenemase plasmid to an E. coli recipient, conferring resistance to 1st-5th generation cephalosporins (including combinations with beta-lactamase inhibitors), penicillins, monobactams, and carbapenems. Conclusions We reported the isolation in Chile of high-risk carbapenem-resistant hvKp carrying a highly transmissible conjugative plasmid encoding KPC-2 and VIM-1 carbapenemases, conferring resistance to most beta-lactams. Furthermore, the lack of hypermucoviscosity argues against this trait as a reliable hvKp marker. These findings highlight the rapid evolution towards multi-drug resistance of hvKp in Chile and globally, as well as the importance of conjugative plasmids and other mobile genetic elements in this convergence. In this regard, genomic approaches provide valuable support to monitor and obtain essential information on these priority pathogens and mobile elements.
RÉSUMÉ
Resumen La determinación de anticuerpos anti virus hepatitis E (anti-VHE) tiene gran variabilidad dependiendo del ensayo utilizado. En 2015, con un método ELISA manual, publicamos una seroprevalencia de anti-VHE IgG de 32,6% en pacientes con estudio de hepatitis. Existen escasas publicaciones de anti-VHE IgM. Recientemente, se desarrolló el primer método automatizado y en el presente estudio comunicamos la experiencia obtenida. Se analizaron los resultados de 272 pacientes con estudio de anti-VHE IgG y/o IgM mediante técnica automatizada ELFA (VIDAS®), entre mayo de 2018 y agosto de 2020. Se encontró 25,8% (68/264) de positividad para anti-VHE IgG y 3,5% (9/259) para anti-VHE IgM. Cuatro muestras tuvieron ambos anticuerpos positivos. La seropositividad de anti-VHE IgG aumentó con la edad. En conclusión, la seroprevalencia de anti-VHE IgG obtenida fue similar a la publicada previamente. Considerando las ventajas de los ensayos IgM e IgG anti-VHE en el sistema VIDAS®, parecen ser nuevas herramientas valiosas en el estudio serológico de VHE.
Abstract The determination of anti-hepatitis E virus antibodies (anti-HEV) has a high variability depending on the assay used. In 2015, with a manual ELISA method, we reported anti-HEV IgG seroprevalence of 32.6% in patients under hepatitis study. There are few reports of anti-HEV IgM. Recently, it was developed the first automated method and in the present study, we report the experience using this new method. Between May 2018 and August 2020, the results of 272 patients with an anti-HEV IgG and/or IgM study were analyzed using the automated ELFA technique (VIDAS®). Seroprevalence was 25.8% (68/264) for anti-HEV IgG and 3.5% (9/259) for anti-HEV IgM. Four samples were positive for both antibodies. Anti-HEV IgG seropositivity increased with age. In conclusion, the seroprevalence of anti-HEV IgG obtained was similar to previously reported. Taking into account the advantages of these assays, anti-HEV IgM and IgG assays on VIDAS® system, seem to be valuable new tools in serological study of HEV.