The prevalence of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-producing E. coli) has recently increased worldwide. This study aims at determining the antimicrobial susceptibility patterns of a collection of clinical E. coli urine isolates and evaluating the ESBL carriage of these isolates at phenotypic and genotypic levels. A total of 100 E. coli urine isolates were collected at a tertiary healthcare centre in Riyadh from January 2018 to March 2018. Antimicrobial susceptibility testing was carried out for all isolates. ESBL production was characterized at phenotypic and genotypic levels using double-disc synergy test and polymerase chain reaction, respectively. Detection of different ESBL variants was performed using DNA sequencing. Of 100 E. coli isolates, 67 were associated with multidrug resistance (MDR) phenotype. All isolates showed variable resistance levels to all antibiotics used here expect to imipenem, where they were all imipenem-sensitive. 33 out of 100 E. coli isolates were positive for ESBLs by phenotypic and genotypic methods. Among all ESBL-positive E. coli isolates, the CTX-M was the most prevalent ESBL type (31/33 isolates; 93.94%). CTX-M-15 variant was detected in all isolates associated with CTX-M carriage. Multiple ESBL gene carriage was detected in 15/33 isolates (45.45%), where 11 (33.33%) isolates produced two different ESBL types while 4 isolates (12.12%) associated with carrying three different ESBL types. Our study documented the high antimicrobial resistance of ESBL-producing E. coli to many front-line antibiotics currently used to treat UTI patients, and this implies the need to continuously revise the local guidelines used for optimal empirical therapy for UTI patients. It also showed the high prevalence of ESBL carriage in E. coli urine isolates, with CTX-M-15 being the most predominant CTX-M variant.

Nanotechnology and nanoparticles (NPs) have increasingly been studied as an alternative for antibiotics because of the feasibility to be used in implantable devices both for bacterial detection and infection prevention. The low rate of resistance development against NPs because of its multiple mode of action has contributed to its increased acceptance in clinical setting. Further development of NPs and their anticancer activity against many human cancer cell lines including breast and ovarian have been documented. Fe₂O₃-NPs could be used for antibacterial and anticancer activity assessment. Iron oxide, apart from being available extensively and cheap, also plays a role in multiple biological processes, making it an interesting metal for NPs. The aim of the present study revolves around generation and characterization of iron oxide Fe₂O₃-NPs, followed by assessment of its antimicrobial and anticancer activities. Synthesis of Fe₂O₃-NPs was performed by hydrothermal approach, and its characterization was done by UV-visible, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) analyses, and transmission electron microscopy (TEM). Antimicrobial activity was checked by agar diffusion assay against Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Candida albicans. Anticancer activity of the NPs was assessed using the human cancer cell lines including cervical carcinoma cell line (HeLa) and MCF7. The developed Fe₂O₃-NPs exhibited a characteristic absorption curve in the 500-600nm wavelength range by UV-visible analysis, the XRD peaks were found to index the rhombohedral shape, and the FTIR analysis ascertained the bonds and functional groups at wavenumber from 400 to 4000cm^-1. Antimicrobial assay detected significant effect against Staphylococcus aureus and Bacillus subtilis with zones of inhibition: 21 and 22mm, respectively. Likewise, Fe₂O₃-NPs show good activity towards tested fungal strain Candida albicans with zone of inhibition of 24mm. The 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay identified significant anticancer activity of the NPs against both cell lines. Our study documents the successful generation and characterization of Fe₂O₃-NPs having excellent antimicrobial and anticancer activities.

The current study aimed to screen the preliminary phytochemicals in the leaf extract of the medicinal plant Simarouba glauca and to analyze its potential antimicrobial, antioxidant and anticancer properties. The phytochemical profile of the methanol extract was analyzed, and bioactive compounds were identified using chromatography, FTIR and GCMS. Antimicrobial activity and Minimum Inhibitory Concentration (MIC) were determined against 14 bacterial and 6 fungal strains. Moreover, the synergistic effect of a plant extract with commercially available antibiotics was also evaluated using the checkerboard method. The ethanolic and methanolic extracts showed exclusive activity against S. aureus and profound activity against E. coli and S. marcescens. Upon comparing breakpoints, methanolic extract demonstrated higher antimicrobial activity with a MIC value of 3.2 mg/mL against the test pathogens. Furthermore, the extracts demonstrated potential antioxidant activity; methanol extract had higher antioxidant potential compared to the ethanol extract. The major proactive bioactive compound with maximum antioxidant capacity was observed to be terpenoids. The methanol extract of S. glauca showed significant cytotoxicity against the MCF-7 breast cancer cell line with an IC₅₀ value of 16.12 µg/mL. The overall results of our work provide significant evidence for the usage of methanolic extract of S. glauca as an efficient ethnomedicinal agent and a potential candidate for relieving many human ailments.

The antimicrobial resistance of extraintestinal pathogenic Escherichia coli (ExPEC) has progressively been reported worldwide. This resistance has been ascribed to global dissemination of a single E. coli clone, namely E. coli sequence type 131 (E. coli ST131). The main goal of this study is to determine the prevalence and molecular traits of ST131 and its subclones among E. coli clinical urine isolates in Riyadh, Saudi Arabia. Sixty E. coli urine isolates, of different extended spectrum β-lactamase (ESBL) carriage, were involved in this study. Molecular characterization was carried out to determine the ST131 status, phylogenetic groups and virulence carriage of these isolates. ST131 isolates were further tested to evaluate the prevalence of different phylogenetic groups, subclones and virulence carriage. Group B2 was the most common phylogroup from which E. coli isolates derived. Overall, 37 of 60 (61.7%) isolates belonged to ST131 clones. Of these, 19 (31.7%) isolates were from the H30 subclone, including 10 (16.7%) H30 non-Rx and 9 (15%) H30Rx. The remaining 18 (30%) ST131 isolates belonged to other non H30 subclones. H30 subclone was significantly higher in the virulence carriage in comparison to non H30 ST131 subclones. This study reported the prevalence and traits of clinical E. coli ST131 main subclones in Saudi Arabia. It also demonstrated the high prevalence of E. coli ST131 locally, and found different virulence genotypes and antimicrobial resistance phenotypes among ST131 subclones. In the future, preforming whole genome sequence-based studies on ST131 and its subclones is crucial to elucidate factors that drive the success of these organisms.

Gram-negative bacteria (GNB) represent a major source of morbidity worldwide. The antimicrobial resistance of GNB has recently increased worldwide, that led to using colistin to treat multidrug resistant (MDR) GNB infections. Annually, Saudi Arabia hosts mass religious occasions, where the risk of infectious disease transmission is very high. This review aimed to provide an update on the current prevalence and molecular epidemiology of colistin-resistant GNB locally. It also assessed the role of mass gatherings in triggering colistin resistance. Although colistin is still highly effective against GNB isolates locally, high colistin resistance has been identified among major GNB such as Acinetobacter baumannii and Klebsiella pneumoniae. Colistin resistance among certain MDR Escherichia coli clones, such as ST131, has recently emerged and this is alarming given the rapid global dissemination of this clone. Local data has shown the role of mass religious gatherings in triggering the acquisition of colistin resistance, which makes the screening of colistin resistance determinants very important to limit the spread of colistin resistant GNB between pilgrims.