Molecular Analysis of Carbapenem Resistance Genes in Citrobacter Strains

چکیده

Citrobacter is a Gram-negative, motile, opportunistic pathogenic bacillus that causes nosocomial infections in affected individuals. In this study, the antibiotic resistance pattern and the presence of carbapenem resistance genes in Citrobacter isolates were investigated. This research was conducted in 2020 on 50 Citrobacter isolates obtained from hospitalized patients at Imam Reza Hospital in Kermanshah, consisting of 32 Citrobacter freundii and 18 Citrobacter koseri isolates. Antibiotic susceptibility and resistance in the isolates were determined by the disk diffusion method for the following antibiotics: doripenem (10 µg), ertapenem (10 µg), meropenem (10 µg), imipenem (10 µg), cefotaxime (30 µg), ceftazidime (30 µg), ceftriaxone (30 µg), ciprofloxacin (5 µg), cefoxitin (30 µg), amikacin (30 µg), and gentamicin (10 µg), based on the 2020 CLSI guidelines. Bacterial genomic DNA was extracted using the boiling method, and molecular investigation of the KPC, VIM, and IMP genes in the isolates was performed using PCR. The highest and lowest rates of antibiotic resistance were observed against cefotaxime and imipenem, at 18 (36%) and 2 (4%) isolates, respectively; the highest and lowest antibiotic susceptibility were observed for ertapenem and cefotaxime, at 45 (90%) and 29 (58%) isolates, respectively. As a result of the molecular analysis, 4 strains were carbapenemase-positive: 2 isolates carried the KPC gene, 2 isolates carried the VIM gene, and none had the IMP gene. This study showed that Citrobacter strains exhibited lower resistance to antibiotics, particularly carbapenems. The molecular investigation indicated that only a few isolates carried carbapenem resistance genes