Molecular characterization of clinical isolates of Klebsiella pneumoniae carrying blaNDM-1 and blaTEM.

TOLEDANO TABLEROS JE; GAYOSSO VÁZQUEZ C; JARILLO QUIJADA MD; FERNÁNDEZ VAZQUEZ,JL; MORFÍN OTERO R; RODRÍGUEZ NORIEGA E; DI CONZA JOSÉ; GUTKIND GABRIEL; SANTOS PRECIADO JI; GIONO CEREZO S; ALCÁNTAR CURIEL MD

Oaxaca

Congreso; VI Congreso de Bioquímica y Biología Molecular de Bacterias y VI Congreso Nacional de Microbiología.; 2019

INTRODUCTION. Klebsiella pneumoniae is a pathogen that exhibits high antimicrobial resistance and belongs to the WHO critical priority group for the development of new antibiotics. Also is a bacteria that "collects" plasmids which allows it to acquire resistance genes from multiple families of antibiotics including β-lactamase enzymes genes due to their wide global spread. OBJECTIVE: Identify molecularly the production of β-lactamases, as well as the plasmid and clonal diversity of clinical isolates of K. pneumoniae that cause nosocomial bacteraemia. MATERIAL AND METHODS. K. pneumoniae isolates were collected during 2017 from the Hospital Civil de Guadalajara (HCG). The identification and susceptibility profile were performed using the Vitek-2 system. The clonality was obtained by performing PFGE. The type of extended-spectrum -lactamase (ESBL) was determined by endpoint PCR and the type of carbapenemases by PCR-multiplex. Resistance transfer was determined by conjugation assays, using E.coli J53-2 as the recipient strain. The visualization of the transfer of plasmids in the obtained transconjugants was resolved by electrophoresis in an Eckhardt gel, and the Inc group to which the plasmids belong was determined by multiplex PCR. The isolates carrying carbapenemases were characterized by multi-locus sequence type (MLST). RESULTS. The 80 isolates were clustered in 69 clones with a similarity of 66%. The phenotypic production of ESBLs was 78% (35/45) and MBLs 22% (10/45). blaTEM gene was carried in 91% (32/35) of the ESBL-producing isolates and 100% (10/10) of the MBL-producing isolates carried blaNDM-1 gene, of these, 20% (2/10) coexisted with blaTEM-type gene and 40% (4/10) with blaTEM -type and blaCTX-M-type genes. The 50% (5/10) of blaNDM-1-producing K. pneumoniae were able to transfer resistance to carbapenems, cephalosporins and aminoglycosides by means of a conjugative plasmid belonging to the IncF family of approximately 195 Kpb. The MLST analysis determined that blaNDM-1-producing isolates belong to ST661, ST683, ST1395, ST2706, ST252, ST1198, ST690, ST1535 and ST3368. CONCLUSIONS. The results demonstrated high variability among K. pneumoniae clones carrying blaNDM-1 and blaTEM plasmidic genes. The transfer of these genes demonstrated the consequent antimicrobial resistance acquisition. Relevantly this is the first report of different STs in K. pneumoniae associated with blaNDM-1 in Mexico.