Abstract

Gram-negative bacteria cause an alarming level of resistance to carbapenems by producing carbapenemases which can become a global epidemic. According to a report about Pseudomonas aeruginosa released by the World Health Organization in 2017, carbapenem resistance is classified as highest priority. The main objectives of the present study are to evaluate the frequency of carbapenem resistance, detect Metallo-beta-Lactamases and beta-lactamases, identify the molecular characterization of bla(NDM-1) in Pseudomonas aeruginosa isolates, and report bla(NDM-)1 for the first time among children in Iran. This study selected 70 clinical isolates from different cities of Iran during 2019-2020. Disk diffusion method and Minimum Inhibitory Concentration were employed to run antimicrobial susceptibility testing. In order to detect carbapenemases and Metallo-beta-Lactamases, mCIM and CDDT were used, respectively. In addition, PCR technique and DNA sequencing were utilized to identify and confirm the genes related to beta-lactamases and Metallo-beta lactamases (bla(NDM), bla(VIM), bla(IMP), bla(SIM), bla(GIM), bla(SPM), and bla(KPC)). The highest resistance rates were observed for Meropenem 67.1 (47) and Imipenem 65.7 (46) while the lowest resistance rate was observed for Piperacillin/Tazobactam 35.7 (25). Of all isolates, 55.7 (39) and 54.3 (38) constituted carbapenemase-producing and MBL isolates, respectively. PCR results exhibited bla(NDM-1) 21.4, followed by bla(IMP) 7.1 and bla(VIM) 2.9 of genes. Moreover, 1.4 of these isolates co-produced bla(NDM-1) and bla(VIM) genes. These isolates did not comprise bla(SIM), bla(SPM), bla(GIM), and bla(KPC) genes. Three isolates of positive bla(NDM-1) isolates were notably detected among children. The results showed that Metallo-beta-Lactamases, especially bla(NDM-1), were highly prevalent among adults and children of Iran.