Insights on the evolution of bacterial susceptibility exposed to multiple antibiotics: a triennial epidemiological study Conference Paper uri icon


  • Introduction: The emergence and propagation of multi-resistant bacteria in the hospital environment have become serious epidemiological and therapeutic problems. It is essential to update data regarding the susceptibility to the most commonly used antibiotics in each hospital, allowing obtaining specific resistance patterns to define the antibiotic therapy. Objectives: This study aims to establish a profile of susceptibility vs. resistance for different microorganisms isolated during 3 years (2009-2011) using 3300 clinical isolates of different biological samples obtained from different hospital units belonging to Centro Hospitalar de Trás-os-Montes e Alto Douro (CHTMAD). Methods: Identification and susceptibility tests were done using microdilution plate method and results were submitted to principal component analysis (PCA). Results: Methicillin resistant Staphylococcus aureus (MRSA), Enterococcus faecium and coagulase negative Staphylococcus (CNS) seem to be the most concerning Gram positive microorganisms. For Gram negative species, despite the high resistance presented by Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBL) to b-lactamic antibiotics, imipenem is still a good therapeutic option, as well as fosfomycin (for urinary infection). Stenotrophomonas maltophilia, Pseudomonas aeruginosa MR and Acinetobacter baumannii, are progressively acquiring higher resistance to these antibiotics, mainly to imipenem, cotrimoxazol and even aminoglycosides (tobramycin and gentamycin). Conclusions: Overall, the developed resistance seems to be directly associated with antibiotics use and, therefore, studies centered in multi-resistance to antibiotics are crucial to establish dynamic protocols adequate to specific resistance vs. susceptibility profiles.

publication date

  • January 1, 2014