Abstract
Background and Objectives: β-lactam antimicrobials represent the most common agents used for treatment of bacterial infections. β-lactamase production among gram negative bacteria is one of the leading cause of antibiotic resistance worldwide. The persistent exposure of bacterial strains to a multitude of β-lactams has induced dynamic and continuous production and mutation of β-lactamases in these bacteria, expanding their activity even against the newly developed antibiotics. Extended-spectrum β-lactamase (ESBL) producing bacteria are main problems for the current antimicrobial resistance study groups. This study aimed at evaluating the frequency of ESBL producing gram negative bacilli isolated from hospitalized patients.
Materials and Methods: In an analytic-descriptive setting, 191 Gram negative bacteria isolated from hospitalized patients admitted in different wards of Sina Hospital, Tabriz were evaluated during a 15-month period. Broth dilution, double disc synergy and E-test were employed for assessing the presence of ESBL-producing organisms. Acinetobacter and Pseudomanas species were excluded due to technical limitations for evaluating the presence of ESBL in these bacteria. The probable risk factors for the presence of ESBL-producing Gram negative bacilli were also evaluated.
Results: Ninety three (49%) isolates were found as the ESBL-producing bacteria. These included Klebsiella pneumoniae (62.9%), Escherichia coli (49.2%) and Enterobacter spp. (19.2%) isolates. Citrobacter spp and Serratia spp. isolates were also found as β-lactamase producing. The duration of stay, hospitalization in ICU, prolonged use of antibiotics, infection with Klebsiella species, catheter usage and previous hospitalization during the last 3 months were significantly related to the presence of ESBL-producing bacilli (P<0.05). The mortality rate was significantly higher in patients infected with ESBL-producing bacteria (11.8% vs. 2%; P=0.041).
Conclusion: The current study showed that the rate of infection with ESBL-producing gram negative bacilli is notable; so preventive policy should be considered, particularly regarding the antibiotic prescriptions.