PREVALENCE OF EXTENDED-SPECTRUM β-LACTAMASES (ESBL) AND CLASS 1 INTEGRONS IN CLINICAL ISOLATES FROM MENDOZA´S HOSPITALS.

MARQUEZ F; NOLLY MB; DAMIANI MT; SANCHEZ DG

Congreso; Congreso Conjunto SAIB SAMIGE 2020; 2021

PREVALENCE OF EXTENDED-SPECTRUM β-LACTAMASES (ESBL) AND CLASS 1 INTEGRONS IN CLINICAL ISOLATES FROM MENDOZA´S HOSPITALS.Marquez F1, Nolly MB1,2, Damiani MT1,2, Sánchez DG1,2.1Laboratorio de Bioquímica e Inmunidad, Instituto de Bioquímica y Biotecnología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo. 2IMBECU-CONICET, Mendoza. Argentina. E-mail: dgsanch@yahoo.com.arβ-lactams are highly efficient against bacterial penicillin-binding proteins by blocking the synthesis of bacterial cell walls. However, this antibiotic benefit is limited due to bacterial resistance mechanisms such as β-lactamases. Mutations in genes encoding these enzymes enable bacteria to expand the hydrolyze substrates, receiving the name of extended-spectrum β-lactamases (ESBL). ESBL degrade penicillin, third and fourth-generation cephalosporins, and monobactams. ESBL are inhibited by clavulanic acid, sulbactam, and tazobactam. TEM-1 and SHV-1 were the first β-lactamases found, afterwards CTX-M, PER, and then the less frequently VEB-1, BES-1, SFO-1, TLA-1, CME-1, GES/IBS, OXA extensively increasing bacterial resistance. β-lactamase resistance can be acquired by bacteria through vertically or horizontally transmission. These resistance gene elements can be incorporated into gene cassettes within integrons, mobilized by phages or plasmids. Integrons are assembly platforms that include genes through site-specific recombination. Dissemination of antibiotic resistance genes by genetic elements is a growing concern worldwide. Especially those related to class 1 integron capable of carrying multiple antibiotic-resistance for third/fourth cephalosporins generation and carbapenems. Resistance cassettes dissemination studies are an extremely relevant issue that concerns antibiotic administration policies. Bacteria can survive the adverse conditions found in the hospital environment, and the use of antibiotic pressure turns them multi-resistant to various antimicrobials. Nosocomial infections are among the most common complications in intensive care units. Our goal is to determine the occurrence of extended-spectrum beta-lactamases (ESBL) and class 1 integron in clinical isolates from local hospitals using PCR techniques. Gene expression responsible for the ESBL phenotype was analyzed, revealing a prevalence for CTX-M1 in 46.4% samples, CTX-M2 in 4% samples, and finally, TEM-1 81.25% samples for the strains analyzed so far. Our studies show that 53 of the 68 bacterial strains obtained (78%) are positive for class 1 integron. Also, plasmids were positive in 17% of the samples examined at the moment. Our results provide a general overview of the gene-prevalence with ESBL activity and the possible horizontal transfer mechanisms by which these genes were released in Mendoza hospitals during 2018 and 2019. This prevalence study is essential for antibiotic administration policies to acquired adequate antimicrobial treatment strategies favoring patients? health outcomes.