Infection and Drug Resistance (Nov 2021)
High Rates of Aminoglycoside Methyltransferases Associated with Metallo-Beta-Lactamases in Multidrug-Resistant and Extensively Drug-Resistant Pseudomonas aeruginosa Clinical Isolates from a Tertiary Care Hospital in Egypt
Abstract
Amira El-Far,1 Safia Samir,2 Eman El-Gebaly,3,4 Maysa Omar,1 Heba Dahroug,1 Ahmed El-Shenawy,1 Noha Salah Soliman,5 Doaa Gamal1 1Microbiology Department, Theodor Bilharz Research Institute (TBRI), Cairo, Egypt; 2Biochemistry and Molecular Biology Department, Theodor Bilharz Research Institute (TBRI), Cairo, Egypt; 3Microbiology and Immunology Department, Faculty of Pharmacy, Beni-Suif University, Beni-Suif, Egypt; 4Department of Microbiology and Immunology, Faculty of Pharmacy, October 6 University, Beni-Suef, 12585, Egypt; 5Clinical and Chemical Pathology Department, Faculty of Medicine, Cairo University, Cairo, EgyptCorrespondence: Safia SamirTheodor Bilharz Research Institute, 1 Cornish El-Nile Street, Warrak El-Hadar, Giza, 12411, Cairo, EgyptTel +20 235401019Fax +20 235408125Email [email protected]; [email protected]: Multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Pseudomonas aeruginosa are the leading cause of healthcare-associated infections worldwide.Objective: The aim was to identify the resistant phenotypes among P. aeruginosa and to characterize different aminoglycosides and carbapenem resistance genes as major mechanisms of resistance in these isolates, in Theodor Bilharz Research Institute (TBRI), a tertiary care hospital in Cairo, Egypt.Methods: During a period of 11 months, 42 P. aeruginosa clinical isolates were collected from the microbiology laboratory by routine culture. Antimicrobial sensitivity testing to the aminoglycosides gentamicin and amikacin, and other classes of antibiotics, was performed by a disk diffusion method. Isolates were tested for aminoglycoside resistance genes, aac(6ʹ)-lb, aac-(3)-lla, rmtB, rmtC, armA, rmtD, and rmtF, and carbapenemase resistance genes blaNDM, blaVIM, and blaIMP, using conventional PCR.Results: Thirty-three (78.5%) of the clinical P. aeruginosa isolates showed MDR and XDR phenotypes at 42.4% and 57.65%, respectively, and these were included in the study. Aminoglycoside resistance was found in 97%, whereas carbapenem resistance was found in 81% of the isolates phenotypically. Only 59.4% (19/26) of the aminoglycoside-resistant isolates harbored resistance genes; none of the amikacin-susceptible isolates harbored any of the tested aminoglycoside resistance genes. Aminoglycoside resistance genes rmtB, armA, aac(6ʹ)-lb, and rmtF were found at rates of 17/33 (51.5%), 3/33 (9%), 2/33 (6%), and 2/33 (6%), respectively, whereas rmtD, acc(3)-II, and rmtC were not detected. Only 40.7% (11/27) of the carbapenem-resistant isolates harbored resistance genes. Carbapenem resistance genes, blaNDM andblaVIM, were found at rates of 7/33 (21.2%) and 6/33 (18.1%), respectively, and blaIMP was not detected.Conclusion: Rates of MDR and XDR P. aeruginosa and resistance to aminoglycosides and carbapenems in our setting are high. Methyltransferases and metallo-beta-lactamases are the main mechanisms of resistance to aminoglycosides and carbapenems, respectively. The presence of blaNDM and rmtF in the strains confirms their rapid dissemination in the Egyptian environment.Keywords: aminoglycosides, carbapenems, antibiotic resistance, Pseudomonas aeruginosa, MDR, XDR, rmtB, rmtF, NDM
