Investigation of Metallobetalactamase (blaIMP & blaVIM) and Carbapenemase (blaKPC & blaGES) Genes in Gram Negative Rods Isolated from Cancer Patients

Bacterial infections are the most common complication in cancer patients. Infection with multi-drug resistant bacteria has recently become a worrying phenomenon in cancer patients. This study focused on Gram-negative bacteria isolated from clinical samples of cancer patients. The purpose of this study was to evaluate the presence and prevalence of drug resistance genes, including metallobetalactamase (blaIMP and blaVIM) and carbapenemase (blaKPC and blaGES) genes, in the main bacteria agents of nosocomial infections in cancer patients, such as Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli.

Common biochemical methods were used to identify bacterial isolates. Antimicrobial susceptibility testing was performed according to the standard method recommended by the Clinical and Laboratory Standards Institute (2019). Polymerase chain reaction (PCR) method was also used to check the presence and prevalence of resistance genes.

During six months, from May to November 2020, 250 clinical samples were collected from cancer patients in Ayatollah Khansari hospital in Arak city, Iran. From which 80 Gram-negative bacilli were isolated, including 33 (41.2%) E. coli, 15 (18.7%) A. baumannii complex, 12 (15%) P. aeruginosa, eight (10%) K. pneumoniae, seven (8.7%) Citrobacter freundii, and five (6.2%) Enterobacter aerogenes isolates. The frequency of blaKPC, blaGES, blaIMP, and blaVIM genes was 39.95, 21.25, 16.25, and 17.45%, respectively.

The present study emphasizes the importance of identifying Gram negative rods and their resistance genes (metallobetalactamase and carbapenemase genes) in cancer patients, carrying out preventive instructions to prevent the transmission of resistance genes, and reducing mortality in these patients.