Prevalence of carbapenem resistance among multidrug-resistant Gram-negative uropathogens

Multidrug-resistant (MDR) uropathogens have become a public health threat, especially in developing countries. Carbapenems are a class of antimicrobial agents often reserved for infections caused by MDR microorganisms. The aim of this study was to determine the prevalence and genotypic basis of plasmid-mediated carbapenem resistance among MDR uropathogens from one of the major clinical settings in Cairo, Egypt. A total of 150 bacterial isolates from patients suffering from urinary tract infections were collected from the Microbiology lab of El-Demerdash Hospital, Cairo, Egypt. All isolates were identified using standard methods. Antimicrobial susceptibility testing was carried out by Kirby Bauer's disk diffusion method following the CLSI guidelines. Plasmids were extracted from MDR uropathogens that also showed carbapenem resistance to be used as templates for PCR amplification. The resulting amplicons were subjected to DNA sequencing. The extracted plasmids were also transformed into Escherichia coli DH5α to compare the phenotypic resistance of the transformants with that of the clinical isolates from which the plasmids were extracted. Of the 150 collected isolates, 116 (77.3%) were Gram-negative, 51 of which (44%) were MDR. Carbapenem resistance was observed in 16/51 (31.4%) of the MDR isolates, 12 of which harbored plasmids. The blaOXA gene was detected in the plasmids of only 9 MDR carbapenem-resistant isolates. From this study, it can be concluded that Gram-negative uropathogens show high rates of multidrug-resistance. The prevalence of MDR uropathogens that are also carbapenem-resistant has increased greatly over the past few years, and this resistance can be easily acquired by horizontal transfer.