In this study Ag nanoparticles (AgNPs), ZnO nanoparticles (ZnONPs), and Ag/ZnO nanocomposites were greenly synthesized and loaded on activated carbon via three different routes: simple impregnation, successive precipitation, and co-precipitation. Neem leaf extract was used as a reducing and stabilizing agent. The morphological and structural properties of the synthesized nanocomposites have been examined using different analytical techniques such as XRD, SEM, FTIR, and UV. The antibacterial and catalytic activity of the synthesized nanocomposites were examined and compared. The results showed that AgNPs loaded on activated carbon (Ag/AC) has the best catalytic activity compared to the other nanocomposites, which is attributed to the good dispersal of AgNPs on the surface of activated carbon. Furthermore, AgNPs showed the best antibacterial effect on eight out of 16 tested pathogens. Results also showed that the order of precipitation is an important factor, as both antibacterial activities and photodegradation activities were higher for ZnO/Ag/AC than Ag/ZnO/AC. Furthermore, the co-precipitation method was shown to be better than the successive precipitation method for 4-nitrophenol photodegradation and 14 out of the 16 antibacterial tests performed.

We determined an antibiotic resistance mechanism in the eastern region, KSA, and the genetic factor clonal relatedness within Gram-negative bacteria. During our retrospective study, a total number of 29 E. coli ESBL producer strains were isolated for patients visiting King Fahad Hospital, Al-Ahsa, KSA. The bla genes were detected via PCR and identified via sequencing. Associated plasmid-mediated quinolone resistance genes, as well as int1 and int2 genes, were also studied. Phylogenetic groups, the ST131 clone, virulence factors, and PFGE were also checked. The bla_CTX-M-9 (3.7%), bla_CTX-M-27 (22.2%), and bla_CTX-M-15 (77.8%) genes were identified; however, the bla_CMY-42 (7.4%) gene was recorded for the first time in KSA. The qnrS1 gene was found in 44.4% of strains, and among them, 50% concomitantly harbored the aac(6′)Ib-cr. The int1 gene was detected in 25.9% strains; nonetheless, the int2 gene was found in 7.4% of isolates. The strains belonged mainly to the B2 and D phylogroups. PFGE showed unrelated patterns. Some isolates belonged to the pandemic clone ST131. We describe a large dissemination of antibiotic resistance to third-generation cephalosporins in the eastern region, KSA, with the occurrence of the bla_CMY-42 gene. The clone ST131 seems to be the principal contributor for bla_CTX-M-15 gene spread.