The present study was carried out, using standard techniques, to identify and count the bacterial contamination of hand air dryers, used in washrooms. Bacteria were isolated from the air flow, outlet nozzle of warm air dryers in fifteen air dryers used in these washrooms. Bacteria were found to be relatively numerous in the air flows. Bacterially contaminated air was found to be emitted whenever a warm air dryer was running, even when not being used for hand drying. Our investigation shows that Staphylococcus haemolyticus, Micrococcus luteus, Pseudomonas alcaligenes, Bacillus cereus and Brevundimonad diminuta/vesicularis were emitted from all of the dryers sampled, with 95% showing evidence of the presence of the potential pathogen S. haemolyticus. It is concluded that hot air dryers can deposit pathogenic bacteria onto the hands and body of users. Bacteria are distributed into the general environment whenever dryers are running and could be inhaled by users and none-users alike. The results provide an evidence base for the development and enhancement of hygienic hand drying practices.

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The main aims of this investigation were the isolation of dimeric naphthoquinones, a new class of dinaphthodiospyrols (1–7), from chloroform fractions and screening them for antibacterial, antifungal, and antioxidant potential. The susceptibility of the isolated compounds, namely, dinaphthodiospyrol A (1), dinaphthodiospyrol B (2), dinaphthodiospyrol C (3), dinaphthodiospyrol D (4), dinaphthodiospyrol E (5), dinaphthodiospyrol F (6), and dinaphthodiospyrol G (7) was assessed for antibacterial potential using well diffusion methods. The isolated compounds showed excellent antibacterial activity against selected bacterial strains, including Gram-positive Bacillus subtilis, Streptococcus epidermis, and Bacillus subtilis, and Gram-negative bacteria Klebsiella pneumonia with the zones of inhibition 6 to 26 nm. The standard drug Imipenem showed a maximum inhibitory zone 30 to 35 nm. Similarly, the isolated compounds were screened for antifungal properties, which showed an excellent reduction in the growth of selected fungal strain including Candida albicans, Aspergillus flavus, Fusarium solani, Trichyton logifusus, Microsporum canis , and Candida glabrata. Among all the screened compounds, 7 exhibited good activity (30–49 mm), followed by compounds 5 and 6, (35–46 mm), while compounds 1–4 showed a moderate effect (8–28 mm) against the selected fungal strain against miconazole which showed potent effects (101–110.98 mm). The isolated compounds were also screened for 1, 1-diphenyl-2-picrylhydrazyl (DPPH) activity. In vitro-based free radical was employed using ascorbic acid as a standard antioxidant. The tested compounds (1–7) exhibited significant antioxidant activity in a concentration-dependent manner. The dinaphthodiospyrol 7 exhibited 97.32% scavenging activity, followed by dinaphthodiospyrol 6, 92.01%, and compounds 5 and 4 with 89.90 and 88.43% scavenging activity at 100 μg/mL, respectively; ascorbic acid showed 96.45% scavenging effect. Furthermore, docking analysis was performed to know the exact binding mode of the tetra-substituted derivatives of dinaphthodiospyrols to the selected target proteins. From the docking analysis, it was found that the docking results are well correlated with the experimental observations. In conclusion, the dinaphthodiospyrols exhibited excellent antibacterial, antifungal, and free radical scavenging potential.

Plant-based materials are reported to have a wide range of applications in the environmental and biomedical sectors. In this report, we present an economic and environmentally friendly supported turmeric powder (TP) biomass for the support of Ag, Ni and Cu nanoparticles (NPs) designated as Ag@TP, Ni@TP and Cu@TP. The in situ syntheses of the stated NPs were achieved in aqueous medium using NaBH4 as a reducing agent. The prepared NPs were applied for the degradation of o-nitrophenol (ONP), m-nitrophenol (MNP), p-nitrophenol (PNP), methyl orange (MO), Congo red (CR), rhodamine B (RB) and methylene blue (MB). Initially, Ag@TP, Ni@TP and Cu@TP were screened for the MO dye and antibacterial activity, where Ag@TP displayed the strongest catalytic activity for MO and bactericidal activities as compared to Ni@TP and Cu@TP. The quantity of metal ions adsorbed onto the TP was investigated by atomic absorption spectroscopy. The Ag@TP, Ni@TP and Cu@TP were characterized through X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, thermal gravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDS) and field emission scanning electron microscope (FESEM) analysis.

Cellulose acetate (CA), and CA blended with Nicotiana tabacum ash (ACA) membranes have synthesized and fabricated with zero-valent Fe NPs (ZVI) and named as CA@Fe 0 and ACA@Fe 0. The as-synthesized membranes were inspected for the removal and detoxification of toxic organic pollutants. Comparative studies of CA@Fe 0 and ACA@Fe 0 NPs were investigated for five model pollutants, such as 4-nitrophenol (4NP), methyl orange (MO), Congo red (CR), methylene blue (MB), and bromocresol green (BCG). The kinetic model indicated that the apparent rate constant K app value of ACA@Fe 0 was highest for all model pollutants compared to CA@Fe 0 NPs. The K app value is derived from pseudo-first-order kinetics. The K app value of MO discoloration was 8.17 × 10 −1 min −1 with ACA@Fe 0 which is highest than CA@Fe 0 (3.08 × 10 −1 min −1). The turnover frequency (TOF) was highest for ACA@Fe 0 for all the pollutants compared to CA@Fe 0 and the highest TOF value was found for CR dye with ACA@Fe 0 which is 0.523 h −1. Both the membranes also showed promising antibacterial activity against Salmonella typhi. Furthermore, CA, ACA membrane and CA@Fe 0 and ACA@Fe 0 NPs were characterized through FESEM, EDS, XRD, FTIR and TGA analysis.

Antibiotic resistance in pathogenic bacteria is emerging as an issue of serious concern in bio-medical research as well as food and health organizations. Metal complexes are currently being employed in medical devices for their inhibition to bacterial adherence and antibacterial activities. The primary aim of this study was to evaluate the antibacterial activities of pure metals, including selenium, germanium and lithium on planktonic cultures and biofilms of three bacterial species: S. aureus SH1000, P aeruginosa PA01 and E. coli. O157:H7. The antagonistic effects of selenium, germanium and lithium on these three bacterial species were examined using zone of inhibition assay. The minimum inhibitory concentrations and minimum bactericidal concentrations of antibiotics (rifampicin, mupirocin and ciprofloxacin) and metals (selenium, germanium and lithium) were measured. The minimum biofilm eradication concentrations (MBEC) of metals were determined against biofilms composed of S. aureus SH1000 and P. aeruginosa PA01. Metal susceptibility tests suggested that biofilms displayed increased resistance over their planktonic state. Differential inhibitory effects were observed for different strains of planktonic and biofilm bacteria in response to different metals and their varying concentrations. Amongst the three metals tested, selenium proved to be the most active against all three species, whereas lithium demonstrated the least inhibitory effects. Scanning electron microscope (SEM) image analysis revealed several detrimental structural changes in bacterial cells exposed to metals compared to those grown in the metal-free culture. In conclusion, the results demonstrate the antibacterial efficacy of pure metals against planktonic and biofilm bacteria paving the way for further similar investigations in search of alternative antibacterial agents.

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