Gram-negative bacteria are common causes of urinary tract infections (UTIs). Such pathogens can acquire genes encoding multiple mechanisms of antimicrobial resistance, including carbapenem resistance. The aim of this study was to detect the carbapenemase-producing ability of some Gram-negative bacterial isolates from urine specimens of patients suffering from complicated UTIs at two vital tertiary care hospitals in Cairo, Egypt; to determine the prevalence of carbapenemase genes among plasmid-bearing isolates; and explore the possibility of horizontal gene transfer to other bacterial species. The collected isolates were subjected to antimicrobial susceptibility testing, phenotypic analysis of carbapenemase production, and molecular detection of plasmid-borne carbapenemase genes, then the extracted plasmids were transformed into competent E. coli DH5α. A total of 256 Gram-negative bacterial clinical isolates were collected, 65 (25.4%) isolates showed carbapenem resistance of which 36 (55.4%) were carbapenemase-producers, and of these 31 (47.7%) harbored plasmids. The extracted plasmids were used as templates for PCR amplification of bla_KPC, bla_NDM, bla_VIM, bla_OXA-48, and bla_IMP carbapenemase genes. The bla_OXA-48 gene was detected in 24 (77.4%) of the tested isolates while bla_VIM gene was detected in 8 (25.8%), both bla_KPC and bla_NDM genes were co-present in 1 (3.2%) isolate. Plasmids carrying the bla_OXA-48 gene from 4 K. pneumoniae clinical isolates were successfully transformed into competent E. coli DH5α. The transformants were carbapenemase-producers and acquired resistance to some of the tested antimicrobial agents as compared to untransformed E. coli DH5α. The study concluded that the rate of carbapenem resistance among Gram-negative bacterial uropathogens in Cairo, Egypt is relatively high and can be transferred horizontally to other bacterial host(s).

Background: The emergence of multidrug-resistant (MDR) uropathogens has become a public health threat and current knowledge of the genotypic basis of bacterial resistance is essential for selecting appropriate treatment options. Objectives: To determine the prevalence of antimicrobial resistance among MDR uropathogens and to elucidate the molecular bases of plasmid-mediated resistance. Methods: Bacterial isolates were recovered from urine specimens of 150 out-patients with signs and symptoms of urinary tract infections (UTIs) at El-Demerdash Hospital, Cairo, Egypt. Standard methods were used for identification, antimicrobial suscep- tibility testing was performed according to CLSI guidelines. Results: Among the recovered isolates, 22.7% and 77.3% were Gram-positive, and negative, respectively. Of which; 43.3% were MDR with 60% harboring plasmids. Extended spectrum β-lactamase (ESBL) genes blaCTX-M, blaSHV, and blaTEM were detected on plasmids of 89.7%, 41%, and 84.6% of the tested isolates, respectively. The aminoglycoside resistance gene aac6’-Ib/aac-6’-Ib- cr was found on plasmids of 92.3% of the tested isolates followed by qnrS (92.3%), qnrB (46.2%), and qnrA (7.7%). The most prevalent quinolone efflux pump gene was oqxB (38.5%), followed by oqxA (20.5%), then qepA (10.3%). Conclusion: High levels of resistance to nitrofurans, β-lactam/β-lactamase inhibitor, cephalosporins, aminoglycosides, and fluoroquinolones were detected, and their use as empirical treatment for UTIs has become questionable. Keywords: ESBLs; qnR; plasmid-mediated; uropathgens; antibacterial resistance.

Background: The dissemination of carbapenem resistance via carbapenemases, such as the metallo-β-lactamase NDM, among Enterobacterales poses a public health threat. The aim of this study was to characterize a plasmid carrying the bla_NDM-1 gene, which was extracted from a clinical Klebsiella pneumoniae uropathogen from an Egyptian patient suffering from a urinary tract infection. Methods and results: The recovered plasmid was transformed into competent E. coli DH5α which acquired phenotypic resistance to cefoxitin, ceftazidime, and ampicillin/sulbactam, and intermediate sensitivity to ceftriaxone and imipenem (a carbapenem). Whole plasmid sequencing was performed on the extracted plasmid using the DNBSEQ™ platform. The obtained forward and reverse reads were assembled into contigs using the PRINSEQ and PLACNETw web tools. The obtained contigs were uploaded to PlasmidFinder and ResFinder for in silico plasmid typing and detection of antimicrobial resistance genes, respectively. The final consensus sequence was obtained using the Staden Package software. The plasmid (pNDMKP37, NCBI accession OK623716.1) was typed as an IncX3 plasmid with a size of 46,160 bp and harbored the antibiotic resistance genes bla_NDM-1, ble_MBL, and aph(3’)-VI. The plasmid also carried mobile genetic elements involved in the dissemination of antimicrobial resistance including insertion sequences IS30, IS630, and IS26. Conclusions: This is Egypt’s first report of a transmissible plasmid co-harboring bla_NDM-1 and aph(3’)-VI genes. Moreover, the respective plasmid is of great medical concern as it has caused the horizontal transmission of multidrug-resistant phenotypes to the transformant. Therefore, new guidelines should be implemented for the rational use of broad-spectrum antibiotics, particularly carbapenems.

Introduction Carbapenem antibiotics are among the last-resort treatments for infections caused by multidrug-resistant bacteria. The emergence and spread of carbapenem resistance (CR) have led researchers to seek alternative treatment approaches to antibiotic monotherapy. The goal of this study was to investigate the effect of combining meropenem, a carbapenem antibiotic, with other antibiotics and bacteriophages in vitro against CR Gram-negative uropathogens to detect potential synergism. Methods The checkerboard assay was used to explore potential synergistic effects against 19 CR- Gram-negative uropathogens when combining meropenem with amikacin, colistin, and tigecycline. Bacteriophages were isolated from hospital sewage, morphologically classified, and lytic phages were combined with meropenem for detecting potential synergistic effects against the tested CR Gram-negative uropathogens. Results Combining meropenem with amikacin, colistin, and tigecycline showed additive effects against 89.4%, 63.2%, and 68.4% of the tested CR uropathogens, respectively. Synergism was observed against a CR K. terrigena isolate when meropenem and amikacin were combined at doses of 4 and 8 µg/ml, respectively. The isolated phages belong to the Myoviridae family of the order Caudovirales. In plaque assay, translucent halos were formed around the clear plaques of phages infecting a CR A. baumannii isolate, suggesting the depolymerase-producing ability of these phages. Combining the isolated phages in this study with meropenem did not exhibit any synergistic effect in vitro against the tested isolates. Conclusions Meropenem/amikacin combination showed in vitro synergistic activity against a clinical CR K. terrigena isolate. Synergism was absent upon combining meropenem with the isolated phages in this study against CR Gram-negative uropathogens.