The Prevalence of Antibiotic Resistance Phenotypes and Genotypes in Multidrug-Resistant Bacterial Isolates from the Academic Hospital of Jaén, Spain.

The heterogenicity of antimicrobial resistance genes described in clinically significant bacterial isolates and their potential role in reducing the efficacy of classically effective antibiotics pose a major challenge for global healthcare, especially in infections caused by Gram-negative bacteria. We analyzed 112 multidrug-resistant (MDR) isolates from clinical samples in order to detect high resistance profiles, both phenotypically and genotypically, among four Gram-negative genera (, , and ). We found that 9.8% of the total selected isolates were classified as extensively drug-resistant (XDR) (six isolates identified as and five among isolates). All other isolates were classified as MDR. Almost 100% of the isolates showed positive results for and genes among the samples, one resistance gene () among , and two genetic determinants ( and ) among . In contrast, showed just one high-frequency antibiotic resistance gene (), which was present in 68.42% of the isolates studied. We also describe positive associations between ampicillin and cefotaxime resistance in and the presence of and genes, as well as between the aztreonam resistance phenotype and the presence of gene in . These data may be useful in achieving a better control of infection strategies and antibiotic management in clinical scenarios where these multidrug-resistant Gram-negative pathogens cause higher morbidity and mortality.