In vitro Susceptibility and Resistance Phenotypes in Contemporary Enterobacter Isolates in a University Hospital in Crete, Greece

Aim: To study the evolution in the susceptibility of Enterobacter spp. in Crete, Greece from 2010 to 2015. Methods: Non-duplicate isolates were studied using automated systems. Phenotypic confirmatory tests were applied. Results: A total of 939 Enterobacter isolates were included. Colistin was the most active antibiotic (97.9%) followed by imipenem (96.1%), gentamicin (95.7%), tigecycline (91.8%), cefepime (89.4%), chloramphenicol (85.8%), fosfomycin (85.5%), trimethoprim/sulfamethoxazole (83.3%) and piperacillin/tazobactam (73.3%). Antibiotic resistance did not increase during the study period for most antibiotics. Lower susceptibility was observed among multidrug-resistant strains and carbapenem-nonsusceptible isolates. AmpC was the most common resistant mechanism (21%); carbapenemases (3.7%) and aminoglycoside-modifying enzymes (6.5%) were also detected. Conclusion: A significant proportion of Enterobacter spp. was resistant to several antibiotics, most notably β-lactams.