Antibacterial activity of extracellular biosynthesized iron oxide nanoparticles against locally isolated β-lactamase-producing Escherichia coli from Egypt

Abstract

Nowadays, extended spectrum β-lactamase (ESBL) producing Escherichia coli has been recognized and recorded worldwide as one of the main causing agents and a major contributor to nosocomial infections. The current study aimed to isolate and detect β-lactamase-producing E. coli and use it in the extracellular biosynthesis of iron oxide nanoparticles (Fe2O3 NPs). Fifteen Gram-negative (G-ve), lactose-fermenting, negative citrate and non-spore-forming coliform bacteria were isolated from the total bacterial isolates from water samples. Different tests were performed to detect β-lactamase-producing E. coli isolates including the chromogenic methods as acidimetric and iodometric techniques and the phenotypic methods as cloverleaf test and Masuda double-disc test. ESBL-producing E. coli was detected and confirmed by a modified double disc synergy test using ceftazidime, cefotaxime, ceftriaxone, amoxicillin combined with clavulanic acid, imipenem, cefepime, and cefoxitin. The quantitative assay of β-lactamase was done using a micro-iodometric assay. Among E. coli bacterial isolates, S1B1 isolate (the highest isolate of β-lactamase activity) was selected and tested for the extracellular biosynthesis of Fe2O3 NPs. The produced nanoparticles (NPs) were characterized by UV–visible spectroscopy, X-ray diffraction analysis, Fourier-transform infrared spectroscopy (FTIR), transmission electron microscope and Zeta analysis. Results confirmed the successful biosynthesis of Fe2O3 NPs which displayed an absorption peak at 346 nm and a Fe2O3 crystallographic lattice plane at (104). Fe2O3 NPs were negatively charged spherical-shaped NPs with an average size of ≈ 24 ± 2 nm. The FTIR spectrum refers to the presence of NPs-associated proteins which act as stabilizing and capping agents. Antibacterial activity of Fe2O3 NPs was tested against Staphylococcus aureus ATCC25923, Bacillus cereus ATCC6633 (G+ve bacterium), Pseudomonas aeruginosa ATCC27853 (G-ve bacterium), as well as the β-lactamase-producing E. coli S1B1 strain. Fe2O3 NPs revealed moderate to strong antibacterial action against the tested strains with a minimum inhibition concentration (MIC) ranging from 25 to 40 µg/ml.

Black seed assisted synthesis, characterization, free radical scavenging, antimicrobial and anti-inflammatory activity of iron oxide nanoparticles

“…Upon reaction with oxygen in an aqueous solution, sodium nitroprusside yields nitrite ions. A 100 µL aliquot of sodium nitroprusside solution (5 mM, pH 7.4) was added to 100 µL of various concentrations (10,20,30,40, and 50 µL) of black cumin extract-mediated iron oxide nanoparticles and ascorbic acid (50-1000 µg/mL). The reaction mixture was incubated at 25 °C for 30 min.…”

“…The nanoparticles have a positive charge, while microorganisms have a negative charge, leading to electrostatic attraction and interaction with protein thiol groups, releasing ions that disrupt the cell membrane and cause bacterial death. The size of the nanoparticles also affects their toxicity, with larger particles having a different motion from primary nanoparticles, leading to aggregation and clustering, which affects their activity [39,40].…”