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

Amira El-Far; Safia Samir; Eman El-Gebaly; Maysa Omar; Heba Dahroug; Ahmed El-Shenawy; Noha Salah Soliman; Doaa Gamal

doi:10.2147/IDR.S335582

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

Infect Drug Resist. 2021 Nov 19:14:4849-4858. doi: 10.2147/IDR.S335582. eCollection 2021.

Authors

Amira El-Far¹, Safia Samir², Eman El-Gebaly^{3

4}, Maysa Omar¹, Heba Dahroug¹, Ahmed El-Shenawy¹, Noha Salah Soliman⁵, Doaa Gamal¹

Affiliations

¹ Microbiology Department, Theodor Bilharz Research Institute (TBRI), Cairo, Egypt.
² Biochemistry and Molecular Biology Department, Theodor Bilharz Research Institute (TBRI), Cairo, Egypt.
³ Microbiology and Immunology Department, Faculty of Pharmacy, Beni-Suif University, Beni-Suif, Egypt.
⁴ Department of Microbiology and Immunology, Faculty of Pharmacy, October 6 University, Beni-Suef, 12585, Egypt.
⁵ Clinical and Chemical Pathology Department, Faculty of Medicine, Cairo University, Cairo, Egypt.

Abstract

Background: 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(6')-lb, aac-(3)-lla, rmtB, rmtC, armA, rmtD, and rmtF, and carbapenemase resistance genes bla _NDM, bla _VIM, and bla _IMP, 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(6')-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, bla _NDM andbla _VIM, were found at rates of 7/33 (21.2%) and 6/33 (18.1%), respectively, and bla _IMP 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 bla _NDM and rmtF in the strains confirms their rapid dissemination in the Egyptian environment.

Keywords: MDR; NDM; Pseudomonas aeruginosa; XDR; aminoglycosides; antibiotic resistance; carbapenems; rmtB; rmtF.

Grants and funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.