Characterization of Extended Spectrum β-lactamase and AmpC Producing Organisms Isolated from a Third Level Hospital Patients in Dominican Republic

Abstract

Extended-spectrum β-lactamases (ESBLs) producing Enterobacteriaceae have become a challenge for clinicians as they frequently show co-resistance to other antibiotic classes. AmpC-type β-lactamases (AmpCs), tend to be more difficult to treat as they could be induced during antibiotic therapy. To characterize ESBLs and AmpCs producing organisms, we collected clinical samples identified through MicroScan® as members of the Enterobacteriaceae family and ESBLs producers, following Clinical Laboratory Standards Institute indications, from January through March 2021, in a third level hospital in Santiago de Los Caballeros, Dominican Republic. Samples underwent manual confirmation via ESBL + AmpC screen discs kit (Liofichelm® srl, Italy) and a genotype analysis was done by DNA extraction for detection of specific genes related with ESBL ((blaSHV, blaTEM, blaCTX, and blaCMY-4) or AmpC (CIT, MOX, DHA and FOX) expression. 54 samples were confirmed as ESBL and/or AmpC producers with Escherichia coli as the most frequent (33/61%) followed by Klebsiella sp. (9/17%). blaCTX was detected in 29 (67%) isolates, followed by blaTEM (23/53%) and blaSHV (18 /40%) . Among the AmpC encoding genes, DHA and CIT gene pools were detected in 3 (7%) and 2 (5%) of the samples, respectively. Two or more genes were detected in 19 (44%) samples. All the AmpC genes were found in an isolate which already had, at least, two other β-lactamase encoding genes. In this cohort, ESBLs and AmpCs -producing organisms with multiple resistance genes were detected. Efforts to curb antibiotic availability and to establish antimicrobial stewardship programs are needed.