Effects of iron oxide (Fe ₃ O ₄ ) nanoparticles on Escherichia coli antibiotic‐resistant strains

Abstract

Aims: Antibiotic resistance of different bacteria requires the development of alternative approaches for overcoming this phenomenon. The antibacterial effects of iron oxide (Fe 3 O 4 ) nanoparticles (NPs) (from 50 to 250 lg ml À1 ) on Escherichia coli antibiotic-resistant strains have been aimed. Methods and Results: The study was performed with ampicillin-resistant E. coli DH5a-pUC18 and kanamycin-resistant E. coli pARG-25 stains. Specific growth rate of bacteria (l), lag phase duration and colony-forming units (CFU) were determined to evaluate growth properties. Fe 3 O 4 NPs (average size of 10Á64 AE 4Á73 nm) coated with oleic acid and synthesized by modified coprecipitation method were used. The medium pH, H + efflux, membrane H + conductance, redox potential determinations and H 2 yield assay were done using potentiometer methods. Growth properties were changed by NPs in concentration-dependent manner. NPs decreased (up to twofold) H + -fluxes through bacterial membrane more in E. coli in the presence of the N,N 0dicyclohexylcarbodiimide, inhibitor of ATPase, indicating that antibacterial activity of these NPs was connected with ATP-associated metabolism. Membrane-associated H 2 production was lowered up to twofold. Moreover, the synergetic interactions of NPs and antibiotics were found: combination of NPs and antibiotics provided the higher H + conductance, lower H + -fluxes and H 2 yield. Conclusions: Fe 3 O 4 NPs can be suggested as alternative antibacterial agents, which can substitute antibiotics in different applications. Significance and Impact of the Study: The antibacterial effects of Fe 3 O 4 NPs on the growth properties and membrane activity of E. coli antibiotic-resistant strains have been demonstrated. These NPs have potential as antibacterial agents, which can substitute for antibiotics in bacterial disease treatment in biomedicine, pharmaceutical and environmental applications.

Comparable antibacterial effects and action mechanisms of silver and iron oxide nanoparticles on Escherichia coli and Salmonella typhimurium

“…Similar results were obtained with ampicillin-resistant E. coli DH5α-pUC18 strain (not shown). Citric acid coated Fe 3 O 4 NPs demonstrated more noticeable antibacterial effect than Fe 3 O 4 NPs stabilized by oleic acid 20 . In the case of Ag NPs, as seen in Fig.…”

“…4 A). This decrease indicates an enhancement of reduction processes that characterizes bacterial metabolism under anaerobic conditions and the generation of H 2 1 , 20 . The addition of NPs resulted in a delayed redox potential drop (Fig.…”

“…2 A). In the case of kanamycin-resistant E. coli strains Fe 3 O 4 NPs coated by citric acid showed noticeable antibacterial effect in comparison with oleic acid stabilized Fe 3 O 4 NPs 20 . Ag NPs inhibited ~ 60 to 90% of S. typhimurium MDC1759 and drug-resistant E. coli viable colonies (Fig.…”

“…In our previous studies oleic acid coated Fe 3 O 4 NPs’ effects on Gram-negative Escherichia coli BW25113, ampicillin-resistant E. coli DH5α-pUC18, kanamycin-resistant E. coli pARG-25 stains and Gram-positive Enterococcus hirae ATCC9790 growth and membrane-associated mechanisms have been investigated 20 , 21 . Our results showed that the Fe 3 O 4 NPs demonstrate different effects on Gram-negative and Gram-positive bacteria.…”

Chronic exposure to complex metal oxide nanoparticles elicits rapid resistance in Shewanella oneidensis MR-1

“…45 Other work has also shown an increase in lag phase when bacteria where exposed to metal oxide nanoparticles. 46,47 In Passage D, the population that grew in 50 mg L À1 NMC was successfully cultured in 100 mg L À1 NMC (Fig. S9 †).…”