Detection of New Delhi Metallo-β-lactamases-1 among Pseudomonas aeruginosa isolated from adult and children patients in Iranian hospitals

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-β-Lactamases and β-lactamases, identify the molecular characterization of blaNDM-1 in Pseudomonas aeruginosa isolates, and report blaNDM-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-β-Lactamases, mCIM and CDDT were used, respectively. In addition, PCR technique and DNA sequencing were utilized to identify and confirm the genes related to β-lactamases and Metallo-β lactamases (blaNDM, blaVIM, blaIMP, blaSIM, blaGIM, blaSPM, and blaKPC). 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 blaNDM-1 21.4%, followed by blaIMP 7.1% and blaVIM 2.9% of genes. Moreover, 1.4% of these isolates co-produced blaNDM-1 and blaVIM genes. These isolates did not comprise blaSIM, blaSPM, blaGIM, and blaKPC genes. Three isolates of positive blaNDM-1 isolates were notably detected among children. The results showed that Metallo-β-Lactamases, especially blaNDM-1, were highly prevalent among adults and children of Iran.