Cytotoxic effect of aminoglycoside antibiotics on the mammalian cell lines

Screening and Selection of Antibiotics for Enhanced Production of Astaxanthin by Haematococcus lacustris

Haematococcus lacustris (Girod-Chantrans) Rostafinski (Chlorophyta) is the richest microalgal source of astaxanthin. Natural astaxanthin from H. lacustris has been widely studied and used for commercial production worldwide. In this study, we examined the effects of 11 antibiotics (dihydrostreptomycin sulphate, neomycin, chloramphenicol, penicillin, streptomycin, ampicillin, kanamycin, gentamycin, hygromycin B, tetracycline, and paromomycin) on the biomass dry weight, growth, and astaxanthin yield of H. lacustris using Jaworski's medium without a nitrogen source. Astaxanthin content in H. lacustris was improved in the presence of ampicillin (0.25 g/L, 0.5 g/L, 1 g/L), chloramphenicol (0.25 g/L), and penicillin (0.25 g/L, 0.5 g/L, 1 g/L) in comparison to the control on day 15. The greatest increase in astaxanthin content on day 15 (6.69-fold) was obtained with the addition of penicillin (0.5 g/L) in comparison to the control. Similarly, on day 15, the cell numbers were also the highest for the H. lacustris culture grown with the addition of penicillin (0.5 g/L).

Multifunctional Hydrogel Dressing That Carries Three Antibiotics Simultaneously and Enables Real-Time Ultrasound Bacterial Colony Detection

We have developed a multifunctional hydrogel that can carry three synergistic antibiotics commonly used in clinical practice. This hydrogel was discovered to have drug encapsulation efficiencies of 94% for neomycin, 97% for bacitracin, and 88% for polymyxin B. Drug release data indicated that the release profiles of these three antibiotics were different. A swelling test demonstrated that the hydrogel absorbed liquid after the release of its antibiotics until it became saturated, which occurred within 48 h. Moreover, this hydrogel exhibited excellent antibacterial effects against Escherichia coli and Pseudomonas aeruginosa and biocompatibility; it can thus protect a wound from microbial invasion. When the alginate hydrogel is used to cover a wound, the wound can be checked for colonization at any time using ultrasound imaging; this can thus enable the prevention of wound biofilm formation in the early stages of infection. We evaluated the hydrogel against commercially available wound dressings and discovered that these wound dressings did not have the aforementioned desirable features. In conclusion, our multifunctional hydrogel can carry three types of antibiotics simultaneously and is a suitable medium through which an ultrasound can be performed to detect the growth of colonies in wounds. The hydrogel is expected to make a valuable contribution to the prevention of wound infections in the future.

Amphiphilic aminoglycosides: Modifications that revive old natural product antibiotics

Widely-used Streptomyces-derived antibacterial aminoglycosides have encountered challenges because of antibiotic resistance and toxicity. Today, they are largely relegated to medicinal topical applications. However, chemical modification to amphiphilic aminoglycosides can revive their efficacy against bacterial pathogens and expand their targets to other pathogenic microbes and disorders associated with hyperactive connexin hemichannels. For example, amphiphilic versions of neomycin and neamine are not subject to resistance and have expanded antibacterial spectra, and amphiphilic kanamycins are effective antifungals and have promising therapeutic uses as connexin hemichannel inhibitors. With further research and discoveries aimed at improved formulations and delivery, amphiphilic aminoglycosides may achieve new horizons in pharmacopeia and agriculture for Streptomyces aminoglycosides beyond just serving as topical antibacterials.