Recent developments in detection and therapeutic approaches for antibiotic-resistant bacterial infections.

Owing to the widespread emergence and proliferation of antibiotic-resistant bacteria, the therapeutic benefits of antibiotics have been reduced. In addition, the ongoing evolution of multidrug-resistant pathogens poses a challenge for the scientific community to develop sensitive analytical methods and innovative antimicrobial agents for the detection and treatment of drug-resistant bacterial infections. In this review, we have described the antibiotic resistance mechanisms that occur in bacteria and summarized the recent developments in detection strategies for monitoring drug resistance using different diagnostic methods in three aspects, including electrostatic attraction, chemical reaction, and probe-free analysis. Additionally, to understand the effective inhibition of drug-resistant bacterial growth by recent nano-antibiotics, the underlying antimicrobial mechanisms and efficacy of biogenic silver nanoparticles and antimicrobial peptides, which have shown promise, and the rationale, design, and potential improvements to these methods are also highlighted in this review. Finally, the primary challenges and future trends in the rational design of facile sensing platforms and novel antibacterial agents against superbugs are discussed.

Evaluating Antioxidant Performance, Biosafety, and Antimicrobial Efficacy of Houttuynia cordata Extract and Microwave-Assisted Synthesis of Biogenic Silver Nano-Antibiotics.

From the traditional Chinese medicine point of view, although Houttuynia cordata extract (HCE) possesses an incredible amount of phytonutrients and exhibits antioxidant activities, excessive doses of HCE can cause danger to organisms and lead to death. In this study, we first examine HCE's overall phenolic and flavonoid content, antioxidant efficacy, and antibacterial activity. Results show that HCE is suitable as a bio-reducing agent for the microwave-assisted synthesis of silver nanoparticles (HCE-AgNPs) with enhanced antioxidant and antimicrobial performance. Under an optimized microwave condition (i.e., 100 °C for 10 min), the HCE-stabilized AgNPs were confirmed with a UV-visible peak at 430 nm and 19.7 ± 4.2 nm in size. Physicochemical properties of HCE-AgNPs were extensively characterized by zeta-potential, FT-IR, XRD, and XPS measurements. Compared to the HC extract counterpart, HCE-AgNPs display superior antioxidant activity, higher DPPH scavenging efficiency, and enhanced broad-spectrum bactericidal activity to inhibit the growth of all tested bacterial strains at doses of 2 µg/mL. Biosafety evaluation indicated that HCE-AgNPs are noncytotoxic on human red blood cells. These data show that the microwave synthesis of AgNPs exhibits a great antioxidant ability, superior antibacterial activity, and a trivial hemolytic effect, providing another bactericidal therapy strategy to address the increasing healthcare-associated infections.

Systematic Evaluation of Antioxidant Efficiency and Antibacterial Mechanism of Bitter Gourd Extract Stabilized Silver Nanoparticles.

In this study, we accentuate the facile and green synthesis of ecologically viable silver nanoparticles (AgNPs) using aqueous (A-BGE) and ethanolic (E-BGE) dried bitter gourd (Momordica charantia) fruit extract as reducing and capping agents. Although AgNPs synthesized using BGEs have been reported earlier in fundamental antimicrobial studies, the possible antioxidant activity, antibacterial efficacy against superbugs, and a potential antimicrobial mechanism are still lacking. The characterization of as-prepared AgNPs was studied through UV-vis, TEM, Zeta-potential, FT-IR, XRD, and XPS analysis. The antioxidant ability of BG-AgNPs was extensively evaluated through DPPH and FRAP assays, which showed that A-BG-AgNPs possessed higher scavenging ability and superior reducing power due to the high phenolic content present in the BG extract. Furthermore, A-BG-AgNPs were highly stable in various physiological media and displayed excellent antibacterial activity against drug-resistant bacterial strains (i.e., MIC value of 4 µg/mL). The generation of reactive oxygen species evidenced that the possible antimicrobial mechanism was induced by BG-AgNPs, resulting in bacterial cell damage. Within the minimal hemolysis, the BG-mediated AgNPs possessed synergistic antioxidant and antibacterial agents and open another avenue for the inhibition of the growth of pathogens.