Caracterización de la resistencia a tigeciclina mediada por plásmidos en Acinetobacter baumannii de origen ecuatoriano

Abstract

Antimicrobial resistance (AMR) is a threat to the world's health systems. Carbapenem-resistant Acinetobacter baumannii (CRAB) is classified as a critical priority pathogen due to its ability to acquire genetic material through mobile elements such as plasmids. The emerging resistance tet(X) genes and its homologs, tet(X3)/tet(X4), encode enzymes that break down last-line antibiotics such as tigecycline (TGC). In Ecuador, there are no studies on the detection of these genes. For this reason, the phenotypic profiles of TGC resistance were evaluated by broth microdilution and genotypic by molecular techniques in the A. baumannii collection from the period 2017-2021 from respiratory samples (sputum, induced sputum, bronchial, tracheal and tracheal aspirate) in Intensive Unit Care patients (ICU). The line of research was Microbiology and biotechnology. The results obtained indicated that the 32 TGC resistant isolates (10.9 percent), clustered in subdivisions R4, R9, R11, R13, and R14 of the total collection (n=292), did not have tet(X) genes or its homologs. Most of the isolates have different combinations of double and triple OXA carbapenemases. Even though there is a decrease of about 3 percent in the TGC resistance rate between the pre-pandemic (2017-2019) and pandemic (2020-2021) periods, the percentage of resistance to other antibiotics was maintained (CIP5, MEM10, IMP10, FEP30, TPZ110) and even increased (COL, CN10, CAZ30). Future research is essential to monitor the spread and potential reservoirs of tet(X) and its variants.