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To control infectious diseases, various applications of nanotechnology have been used to enhance the self-cleaning and antibacterial properties of materials. This study aimed to evaluate the antibacterial properties of face masks coated with TiO2 nanoparticles. The antibacterial efficacies of cloth face masks coated with TiO2 were measured by inoculating them in bacterial suspensions (105 CFUs from both E. coli and S. aureus). The results showed that TiO2 nanoparticle solutions (at 2%) reduced the starting inoculum of 105 CFUs (5 log cfu/cm2) of E. coli and S. aureus to 1.3 and 1.68 log, respectively, with antibacterial activities of 3.7 and 3.34 log, respectively. Furthermore, at a 1% concentration, the antibacterial activities against E. coli and S. aureus were 2.1 and 2.01 log, respectively, while at a low concentration (0.5%), the antibacterial activities against E. coli and S. aureus were 1.8 and 1.72 log, respectively. The CFUs in all the experimental groups were significantly lower than those in the control group (saline). In conclusion, TiO2 nanoparticle solutions with a high concentration (2%) demonstrated a strong antibacterial effect on E. coli and S. aureus, and the difference was statistically significant, while a significant antibacterial activity was demonstrated with lower concentration (0.5% and 1%) nanoparticle solutions of TiO2 after 18 h. There was a statistically significant difference regarding colony reduction between E. coli and S. aureus even at 3 h. The antibacterial activities of TiO2 in face masks could be promising for reducing the risk of bacterial infections.

Several methods of Deoxyribonucleic acid (DNA) extraction have been applied to extract bacterial DNA. The amount and the quality of the DNA obtained for each one of those methods are variable. The study aimed to evaluate bacterial DNA extraction using conventional boiling method followed by alcohol precipitation. DNA extraction from Gram negative bacilli was extracted and precipitated using boiling method with further precipitation by ethanol. The extraction procedure performed using the boiling method resulted in high DNA yields for both E. coli and K. pneumoniae bacteria in (199.7 and 285.7μg/ml, respectively) which was close to control method (229.3 and 440.3μg/ml). It was concluded that after alcohol precipitation boiling procedure was easy, cost-effective, and applicable for high-yield quality of DNA in Gram-negative bacteria.

This study aimed to assess hand hygiene knowledge, perception, and practices of visitors to the Prophet’s Mosque in Al Madinah City, Saudi Arabia. Using a self-administered electronic questionnaire, a cross-sectional survey was conducted among domestic residents, who visited the mosque between 31 July and 3 August 2020. Participants’ demographic data, hand hygiene knowledge, perception, and practices were collected. Four hundred participants aged 18–65 (median 36) years completed the survey, of which 215 (53.8%) were female. The visitors’ mean knowledge score about hand hygiene was 6.4 (± standard deviation (SD) 1.35) of total 12. Most participants (392, 98%) were aware of the role of hand hygiene in preventing Coronavirus Disease 2019 (COVID-19); nevertheless, 384 (96%) said hand hygiene lowers body immunity and 316 (79%) thought <60% alcohol is sufficient for hand disinfection. Males had a higher knowledge score than females (6.46 (±1.41) vs. 6.14 (±1.27), p = 0.02) and, visitors who had no formal education scored higher than those with post-graduate education (6.88 (±1.45) vs 5.73 (±1.12), p = 0.01). Washing hands with soap and water was the predominant method practiced after a meal (365, 91.7%), after toilet visit (354, 88.5%), after touching a surface (262, 65.7%), after waste disposal (332, 83.2%), and when hands were visibly dirty (357, 89.5%). Al Madinah visitors had moderate knowledge about hand hygiene, but demonstrated some knowledge gaps and negligence in practice that are crucial to curb the spread of COVID-19.

The pollution of toxic heavy metals is considered one of the most important environmental issues which has accelerated dramatically due to changing industrial activities. This review focuses on the most common methods, strategies, and biological approaches of heavy metal bioremediation. Also, it provides a general overview of the role of microorganisms in the bioremediation of heavy metals in polluted environments. Advanced methods of heavy metal remediation include physicochemical and biological methods; the latter can be further classified into in situ and ex situ bioremediation. The in situ process includes bioventing, biosparging, biostimulation, bioaugmentation, and phytoremediation. Ex situ bioremediation includes land farming, composting, biopiles, and bioreactors. Bioremediation uses naturally occurring microorganisms such as Pseudomonas, Sphingomonas, Rhodococcus, Alcaligenes, and Mycobacterium. Generally, bioremediation is of very less effort, less labor intensive, cheap, ecofriendly, sustainable, and relatively easy to implement. Most of the disadvantages of bioremediation relate to the slowness and time-consumption; furthermore, the products of biodegradation sometimes become more toxic than the original compound. The performance evaluation of bioremediation might be difficult as it has no acceptable endpoint. There is a need for further studies to develop bioremediation technologies in order to find more biological solutions for bioremediation of heavy metal contamination from different environmental systems.