Phytochemicals as Invaluable Sources of Potent Antimicrobial Agents to Combat Antibiotic Resistance.

Plants have been used for therapeutic purposes against various human ailments for several centuries. Plant-derived natural compounds have been implemented in clinics against microbial diseases. Unfortunately, the emergence of antimicrobial resistance has significantly reduced the efficacy of existing standard antimicrobials. The World Health Organization (WHO) has declared antimicrobial resistance as one of the top 10 global public health threats facing humanity. Therefore, it is the need of the hour to discover new antimicrobial agents against drug-resistant pathogens. In the present article, we have discussed the importance of plant metabolites in the context of their medicinal applications and elaborated on their mechanism of antimicrobial action against human pathogens. The WHO has categorized some drug-resistant bacteria and fungi as critical and high priority based on the need to develope new drugs, and we have considered the plant metabolites that target these bacteria and fungi. We have also emphasized the role of phytochemicals that target deadly viruses such as COVID-19, Ebola, and dengue. Additionally, we have also elaborated on the synergetic effect of plant-derived compounds with standard antimicrobials against clinically important microbes. Overall, this article provides an overview of the importance of considering phytogenous compounds in the development of antimicrobial compounds as therapeutic agents against drug-resistant microbes.

Exploring the antibiogram of soil isolates from an indian hospital precinct: link to antibiotic usage.

OBJECTIVE: Hospitals serve as hotspots of antibiotic resistance. Despite several studies exploring antibiotic resistance in hospitals, none have explored the resistance profile of soil bacteria from a hospital precinct. This study examined and compared the antibiogram of the soil isolates from a hospital and its affiliated university precinct, to determine if antibiotic resistant bacteria were present closer to the hospital. RESULTS: 120 soil samples were collected from JSS Hospital and JSS University in Mysore, India across three consecutive seasons (monsoon, winter and summer). 366 isolates were randomly selected from culture. Antibiotic susceptibility testing was performed on 128 isolates of Pseudomonas (n = 73), Acinetobacter (n = 30), Klebsiella species (n = 15) and Escherichia coli (n = 10). Pseudomonas species exhibited the highest antibiotic resistance. Ticarcillin-clavulanic acid, an extended-spectrum carboxypenicillin antibiotic used to treat moderate-to-severe infections, ranked highest amongst the antibiotics to whom these isolates were resistant (n = 51 out of 73, 69.9%). Moreover, 56.8% (n = 29) were from the hospital and 43.1% (n = 22) were from the university precinct, indicating antibiotic resistant bacteria were closer to the hospital setting. This study highlights the effect of antibiotic usage in hospitals and the influence of anthropogenic activities in the hospital on the dissemination of antibiotic resistance into hospital precinct soil.

Three-dimensional carbon foam-metal oxide-based asymmetric electrodes for high-performance solid-state micro-supercapacitors.

A three-dimensional carbon foam (CF)-based asymmetric planar micro-supercapacitor is fabricated by the direct spray patterning of active materials on an array of interdigital electrodes. The solid-state asymmetric micro-supercapacitor comprises the CF network with pseudocapacitive metal oxides (manganese oxide (MnO), iron oxide (Fe2O3)), where CF-MnO composite as a positive electrode, and CF-Fe2O3 as negative electrode for superior electrochemical performance. The micro-supercapacitor, CF-MnO//CF-Fe2O3, attains an ultrahigh supercapacitance of 18.4 mF cm-2 (2326.8 mF cm-3) at a scan rate of 5 mV s-1. A wider potential window of 1.4 V is achieved with a high energy density of 5 µW h cm-2. The excellent cyclic stability is confirmed by 86.1% capacitance retention after 10 000 electrochemical cycles.

Environmental hotspots for antibiotic resistance genes.

Bacterial resistance toward broad-spectrum antibiotics has become a major concern in recent years. The threat posed by the infectious bacteria and the pace with which resistance determinants are transmitted needs to be deciphered. Soil and water contain unique and diverse microbial communities as well as pools of naturally occurring antibiotics resistant genes. Overuse of antibiotics along with poor sanitary practices expose these indigenous microbial communities to antibiotic resistance genes from other bacteria and accelerate the process of acquisition and dissemination. Clinical settings, where most antibiotics are prescribed, are hypothesized to serve as a major hotspot. The predisposition of the surrounding environments to a pool of antibiotic-resistant bacteria facilitates rapid antibiotic resistance among the indigenous microbiota in the soil, water, and clinical environments via horizontal gene transfer. This provides favorable conditions for the development of more multidrug-resistant pathogens. Limitations in detecting gene transfer mechanisms have likely left us underestimating the role played by the surrounding environmental hotspots in the emergence of multidrug-resistant bacteria. This review aims to identify the major drivers responsible for the spread of antibiotic resistance and hotspots responsible for the acquisition of antibiotic resistance genes.

Novel electrode geometry for high performance CF/Fe2O3 based planar solid state micro-electrochemical capacitors.

A novel geometry of sharp-edged electrodes for planar micro-electrochemical capacitors is utilized for an enhanced performance compared to the conventionally used interdigitated electrodes. The sharp-edged electrode geometry achieves a 68% enhancement in the electric field at the sharp-edge of the electrodes as compared to interdigitated electrodes. Moreover, carbon foam with high specific surface area loaded with iron oxide nanoparticles allows a large mass loading for the pseudocapacitance in addition to electric double layer capacitance (EDLC). Thus, an enhancement of 235% was obtained in both the areal specific capacitance and energy density when the performance was compared with the interdigitated electrode based supercapacitors. Moreover, an excellent cycling stability (∼99.5%) over 10 000 charge-discharge cycles was also achieved. The high-performance architecture of sharp-edged electrodes paves a way for smart electrochemical capacitors using an efficient planar structure in combination with high-loading materials for large pseudocapacitance as well as EDLC.

Uniting Superhydrophobic, Superoleophobic and Lubricant Infused Slippery Behavior on Copper Oxide Nano-structured Substrates.

Alloys, specifically steel, are considered as the workhorse of our society and are inimitable engineering materials in the field of infrastructure, industry and possesses significant applications in our daily life. However, creating a robust synthetic metallic surface that repels various liquids has remained extremely challenging. The wettability of a solid surface is known to be governed by its geometric nano-/micro structure and the chemical composition. Here, we are demonstrating a facile and economical way to generate copper oxide micro-nano structures with spherical (0D), needle (1D) and hierarchical cauliflower (3D) morphologies on galvanized steel substrates using a simple chemical bath deposition method. These nano/micro textured steel surfaces, on subsequent coating of a low surface energy material display excellent superhydrophobic, superoleophobic and slippery behavior. Polydimethylsiloxane coated textured surfaces illustrate superhydrophobicity with water contact angle about 160°(2) and critical sliding angle ~2°. When functionalized with low-surface energy perfluoroalkylsilane, these surfaces display high repellency for low surface tension oils as well as hydrocarbons. Among them, the hierarchical cauliflower morphology exhibits re-entrant structure thereby showing the best superoleophobicity with contact angle 149° for dodecane. Once infused with a lubricant like silicone oil, they show excellent slippery behavior with low contact angle hysteresis (~ 2°) for water drops.