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Cadmium (Cd2+), a naturally occurring heavy metal, is an important environmental pollutant and a potent toxicant to bacteria. The gastrointestinal (GI) tract microflora has a marked capacity to cope with the increased load of ingested metals. However, heavy metals may have harmful effects on GIT microflora. Under the conditions of experimental exposure to cadmium, changes in the population of intestinal microflora in healthy mice were examined. Five experimental groups received 23 to 50 mg kg-1 cadmium in drinking water and control group was given water free from cadmium for 45 days. Intestinal contents and biopsy samples were aseptically collected and bacterial counts were performed. The microflora of the intestine in control group was represented by bacteria of the genera Bacillus cereus, Lactobacillus spp., Clostridium spp., Escherichia coli, Klebsiella spp., Pseudomonas spp., Enterococcus spp. and Proteus spp. As the result of dysbiosis induced by the introduction of cadmium, a sharp decrease in the population of all microbial species in the intestine was observed. The deleterious effect of cadmium appeared to be less in the large intestine and rectum than that of small intestine, suggesting a site-specific influence of cadmium. The gram-negative bacteria tested were less sensitive to cadmium compared to the gram-positive bacteria because of their possible different ability to uptake the metal ions.

Destructive impacts of COVID-19 pandemic worldwide necessitates taking more appropriate measures for mitigating virus spread and development of the effective theranostic agents. In general, high heterogeneity of viruses is a major challenging issue towards the development of effective antiviral agents. Regarding the coronavirus, its high mutation rates can negatively affect virus detection process or the efficiency of drugs and vaccines in development or induce drug resistance. Bioengineered nanomaterials with suitable physicochemical characteristics for site-specific therapeutic delivery, highly-sensitive nanobiosensors for detection of very low virus concentration, and real-time protections using the nanorobots can provide roadmaps towards the imminent breakthroughs in theranostics of a variety of diseases including the COVID-19. Besides revolutionizing the classical disinfection procedures, state-of-the-art nanotechnology-based approaches enable providing the analytical tools for accelerated monitoring of coronavirus and associated biomarkers or drug delivery towards the pulmonary system or other affected organs. Multivalent nanomaterials capable of interaction with multivalent pathogens including the viruses could be suitable candidates for viral detection and prevention of further infections. Besides the inactivation or destruction of the virus, functionalized nanoparticles capable of modulating patient’s immune response might be of great significance for attenuating the exaggerated inflammatory reactions or development of the effective nanovaccines and medications against the virus pandemics including the COVID-19.

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Background:Acne vulgaris is one of the most common skin disorders in youth especially during the puberty.Objective:This in vitro study was performed to determine the antibiotic resistance and sensitivity in acne vulgaris.Materials and Methods:Samples were collected from normal skin and nodulocystic and pustular skin lesions of one hundred youngsters (64 girls, 36 boys) among college students in the age range of 18-24 years old. The specimens were cultured individually on blood agar and Muller-Hinton media. The cultures were then incubated under both aerobic and anaerobic conditions for 2 to 7 days. Bacteria were identified and their resistance to common antibiotics was evaluated according to the standard procedures.Results:In aerobic culture of pustular and nodulocystic skin lesions, Staphylococcus aureus was present in 41% of subjects, Staphylococcus epidermidis in 53% and Micrococcus spp in 45% of subjucts. In anaerobic bacterial culture of pustular and nodulocystic skin lesions, Staphylococcus aureus was present in 39%, Propionibacterium acne in 33% and Staphylococcus epidermidis in 21% of subjects. The results of present study revealed that clindamycin and erythromycin were the least effective antibiotics for Propionibacterium acne while tetracycline was the least effective for Staphylococcus aureus in vitro. A synergic effect of benzoyl peroxide, erythromycin or clindamycin was noticed. Rifampin was the most effective antibiotic in vitro.Conclusion:Our results showed that rifampin was the most sensitive antibiotic in vitro for acne vulgaris. To achieve a better treatment, a combination of rifampin with other antibiotics may be more efficient. We suggest in vivo studies for better evaluation and treatment of acne patients with rifampin.