Distribution of β-Lactamase-Producing Enterobacterales among Patients in Surgical and Therapeutic Departments of a Multidisciplinary Hospital

Adequate empiric therapy is difficult to choose without monitoring the local distribution of antibiotic-resistant bacteria in each hospital. The frequency of β-lactamase-producing Enterobacterales was compared in patients of therapeutic and surgical units. Antibiotic susceptibility was evaluated by the disk diffusion test. Production of extended-spectrum β-lactamases (ESBLs) was detected by the double-disk test, and carbapenemases were determined by a modified carbapenem inactivation method. Carbapenemase genes and their expression were quantified by real-time PCR and immunochromatography. More than one-third of Enterobacterales isolates produced ESBLs in both the therapeutic (35.51%) and surgical (39.85%) units. The proportions of carbapenemase producers was comparable in the two groups, amounting to 8.41 and 9.77%, respectively. Metallo-β-lactamases predominated in the surgical units; and serine β-lactamases, in the therapeutic units. β-Lactamase producers were less frequent among community-acquired isolates than among nosocomial ones in both therapeutic (31.48 and 56.6%) and surgical (45.45 and 51%) units, but the differences were nonsignificant. Although the proportion of β-lactamase producers in the surgical and therapeutic units was not found to increase over three years of the study, local monitoring should certainly be continued in order to develop a local strategy for adequate use of antibacterial drugs.