Antimicrobial agents and microbial ecology

Biocides as drivers of antibiotic resistance: A critical review of environmental implications and public health risks

The widespread and indiscriminate use of biocides poses significant threats to global health, socioeconomic development, and environmental sustainability by accelerating antibiotic resistance. Bacterial resistance development is highly complex and influenced significantly by environmental factors. Increased biocide usage in households, agriculture, livestock farming, industrial settings, and hospitals produces persistent chemical residues that pollute soil and aquatic environments. Such contaminants contribute to the selection and proliferation of resistant bacteria and antimicrobial resistance genes (ARGs), facilitating their dissemination among humans, animals, and ecosystems. In this review, we conduct a critical assessment of four significant issues pertaining to this topic. Specifically, (i) the role of biocides in exerting selective pressure within the environmental resistome, thereby promoting the proliferation of resistant microbial populations and contributing to the global spread of antimicrobial resistance genes (ARGs); (ii) the role of biocides in triggering transient phenotypic adaptations in bacteria, including efflux pump overexpression, membrane alterations, and reduced porin expression, which often result in cross-resistance to multiple antibiotics; (iii) the capacity of biocides to disrupt bacteria and make the genetic content accessible, releasing DNA into the environment that remains intact under certain conditions, facilitating horizontal gene transfer and the spread of resistance determinants; (iv) the capacity of biocides to disrupt bacterial cells, releasing intact DNA into the environment and enhancing horizontal gene transfer of resistance determinants; and (iv) the selective interactions between biocides and bacterial biofilms in the environment, strengthening biofilm cohesion, inducing resistance mechanisms, and creating reservoirs for resistant microorganisms and ARG dissemination. Collectively, this review highlights the critical environmental and public health implications of biocide use, emphasizing an urgent need for strategic interventions to mitigate their role in antibiotic resistance proliferation.

Community Pharmacists' Responses Toward Antimicrobial Prescriptions in Jordan: A Cross-Sectional Survey

Background: Globally, community pharmacists worldwide have prescribed more over-the-counter systemic antibiotics, posing significant issues for international organizations tackling antibiotic-resistant bacteria, a major global threat, due to the accessibility in pharmacies. Objectives: This study aimed to examine the Jordanian pharmacists' antibiotic selection and over-the-counter antibiotic prescriptions. Methods: A total of 244 community pharmacists participated in an online standardized survey, which examined five essential domains including sources and trust of pharmacy antibiotic prescription information, category and frequency of permitted antimicrobials, prescription-free antimicrobials, interactions, antimicrobial prescription issues for pharmacists, and pharmacy staff's knowledge of non-prescription antimicrobial questions and answers. Results: This study found that 1-pharmacists are confident in prescribing antibiotics and they use various tools to improve their skills. 2-Antibiotics were the most sought antimicrobials without a prescription, followed by antifungals and antivirals. 3-Throat, urinary tract, chest, and otitis media are the most common infections that require antibiotics. Pharmacists prescribe penicillin for 75% of throat infections, Fluoroquinolones for 48.2% of urinary tract infections, and cephalosporins for 35.9%. Macrolides are the most prevalent otitis media treatment (43.2%). 4-Some people obtain antimicrobial prescriptions without a valid reason or diagnosis. 5-Many pharmacists (171/244, 70%) agree or strongly believe that antibiotic prescription information is difficult to obtain. 6-Many pharmacists (183/200, 91.5%) aimed to educate patients on the risks and correct use of antimicrobials without prescriptions. Conclusions: These results show that Jordanian community pharmacists follow clinical antibiotic prescribing guidelines and conduct antimicrobial stewardship, yet they demand antimicrobials without prescriptions and lack decision support tools. Antibiotic classes address most diseases, and pharmacists emphasize antimicrobial misuse.

The Therapeutic Potential of West Indian Lemongrass (Cymbopogon citratus) Essential Oil-Based Ointment in the Treatment of Pitted Keratolysis

Background: Due to their antibacterial activities, essential oils can be potential alternatives to antibiotics in certain cases. West Indian lemongrass (Cymbopogon citratus) essential oil (LEO) is effective against a broad range of bacteria by inhibiting spore formation, and is considered safe. In this study, we demonstrated its therapeutical potential in the treatment of pitted keratolysis (PK), a superficial skin infection affecting the pressure-bearing areas of plantar surfaces. Methods: For in vitro antibacterial efficacy testing, LEO was mixed into different ointment bases, including Hydrogelum methylcellulose FoNo VIII., Ungentum oleosum FoNo VIII. (Ung. oleoso), Unguentum stearini FoNo VIII. (Ung. stearin), and Vaselinum cholesterinatum FoNo VIII. (Vasel. cholest.), at different concentrations of 1, 3, and 5%. These formulations were tested on representatives of three bacterial species associated with PK: Kytococcus sedentarius, Dermatophilus congolensis, and Bacillus thuringiensis. Results: In the in vitro tests, Hydrogelum methylcellulose (HM) gel best supported the antibacterial effects of LEO, reducing the number of living bacteria on agar plates by 4-5 orders of magnitude in a concentration-dependent manner during the 30 min exposure times. This was also confirmed by the Franz diffusion cell drug release test; after 30 min, several active compounds could be detected in the HM samples, in contrast to the other bases. Shelf-life experiments showed that the HM base supported the antibacterial features of 3% LEO for at least 2 years without significant loss of efficacy. Conclusions: Our study highlights that ointments containing essential oils potentially have a place in the treatment of PK. Therefore, antibiotics may potentially be replaced for the treatment of PK, thereby reducing environmental antibiotic pressure, which is one of the driving forces behind the spread of antibiotic resistance.

Cannabigerol (CBG): A Comprehensive Review of Its Molecular Mechanisms and Therapeutic Potential

Cannabigerol (CBG), a non-psychoactive cannabinoid found in cannabis, has emerged as a promising therapeutic agent with a diverse range of potential applications. Unlike its well-known counterpart tetrahydrocannabinol (THC), CBG does not induce intoxication, making it an attractive option in the clinic. Recent research has shed light on CBG's intriguing molecular mechanisms, highlighting its potential to modulate multiple physiological processes. This review delves into the current understanding of CBG's molecular interactions and explores its therapeutic power to alleviate various conditions, including cancer, metabolic, pain, and inflammatory disorders, amongst others. We discuss how CBG interacts with the endocannabinoid system and other key signaling pathways, such as CB1, CB2, TPR channels, and α2-adrenoceptor, potentially influencing inflammation, pain, neurodegeneration, and other ailments. Additionally, we highlight the ongoing research efforts aimed at elucidating the full spectrum of CBG's therapeutic potential and its safety profile in clinical settings. Through this comprehensive analysis, we aim to provide a deeper understanding of CBG's role in promoting human health and pave the way for future research endeavors.

New emerging materials with potential antibacterial activities

The increasing prevalence of multidrug-resistant pathogens is a critical public health issue, necessitating the development of alternative antibacterial agents. Examples of these pathogens are methicillin-resistant Staphylococcus aureus (MRSA) and the emergence of "pan-resistant" Gram-negative strains, such as Pseudomonas aeruginosa and Acinetobacter baumannii, which occurred more recently. This review examines various emerging materials with significant antibacterial activities. Among these are nanomaterials such as quantum dots, carbon quantum dots, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and layered double hydroxides, all of which demonstrate excellent antibacterial properties. Interestingly, including antibacterial agents within the structure of these materials can help avoid bacterial resistance and improve the long-term efficacy of the materials. Additionally, the antibacterial potential of liquid solvents, including ionic liquids and both deep eutectic solvents and natural deep eutectic solvents, is explored. The review discusses the synthesis methods, advantages, and antibacterial efficacy of these new materials. By providing a comprehensive overview of these innovative materials, this review aims to contribute to the ongoing search for effective solutions to combat antibiotic resistance. Key studies demonstrating antibacterial effects against pathogens like Escherichia coli, Staphylococcus aureus, and multidrug-resistant strains are summarized. MOFs have exhibited antibacterial properties through controlled ion release and surface interactions. COFs have enhanced the efficacy of encapsulated antibiotics and displayed intrinsic antibacterial activity. Other nanomaterials, such as quantum dots, have generated reactive oxygen species, leading to microbial inactivation. This review aims to provide insights into these new classes of antibacterial materials and highlight them for addressing the global crisis of antibiotic resistance. KEY POINTS: • Nanomaterials show strong antibacterial effects against drug-resistant bacteria • Emerging solvents like ionic liquids offer novel solutions for bacterial resistance • MOFs and COFs enhance antibiotic efficacy, showing promise in combating resistance.

Surveillance of antimicrobial utilization in Africa: a systematic review and meta-analysis of prescription rates, indications, and quality of use from point prevalence surveys

BACKGROUND

Antimicrobial resistance (AMR) is a global public health concern that is fueled by the overuse of antimicrobial agents. Low- and middle-income countries, including those in Africa,. Point prevalence surveys (PPS) have been recognized as valuable tools for assessing antimicrobial utilization and guiding quality improvement initiatives. This systematic review and meta-analysis aimed to evaluate the prescription rates, indications, and quality of antimicrobial use in African health facilities.

METHODS

A comprehensive search was conducted in multiple databases, including PubMed, Scopus, Embase, Hinari (Research4Life) and Google Scholar. Studies reporting the point prevalence of antimicrobial prescription or use in healthcare settings using validated PPS tools were included. The quality of the studies was assessed using the Joanna Briggs Institute (JBI) critical appraisal checklist. A random-effects meta-analysis was conducted to combine the estimates. Heterogeneity was evaluated using Q statistics, I² statistics, meta-regression, and sensitivity analysis. Publication bias was assessed using a funnel plot and Egger's regression test, with a p-value of < 0.05 indicating the presence of bias.

RESULTS

Out of 1790 potential studies identified, 32 articles were included in the meta-analysis. The pooled prescription rate in acute care hospitals was 60%, with significant heterogeneity (I2 = 99%, p < 0.001). Therapeutic prescriptions constituted 62% of all the prescribed antimicrobials. Prescription quality varied: documentation of reasons in notes was 64%, targeted therapy was 10%, and parenteral prescriptions were 65%, with guideline compliance at 48%. Hospital-acquired infections comprised 20% of all prescriptions. Subgroup analyses revealed regional disparities in antimicrobial prescription prevalence, with Western Africa showing a prevalence of 65% and 44% in Southern Africa. Publication bias adjustment estimated the prescription rate at 54.8%, with sensitivity analysis confirming minor variances among studies.

CONCLUSION

This systematic review and meta-analysis provide valuable insights into antimicrobial utilization in African health facilities. The findings highlight the need for improved antimicrobial stewardship and infection control programs to address the high prevalence of irrational antimicrobial prescribing. The study emphasizes the importance of conducting regular surveillance through PPS to gather reliable data on antimicrobial usage, inform policy development, and monitor the effectiveness of interventions aimed at mitigating AMR.

Modified chitosan: Insight on biomedical and industrial applications

Chitosan (CS), a by -product of chitin deacetylation can be useful in a broad range of purposes, to mention agriculture, pharmaceuticals, material science, food and nutrition, biotechnology and of recent, in gene therapy. Chitosan is a highly desired biomolecule due to the existence of many sensitive functional groups inside the molecule and also because of its net cationicity. The latter provides flexibility for creating a wide range of derivatives for particular end users across various industries. This overview aims to compile some of the most recent research on the bio-related applications that chitosan and its derivatives can be used for. However, chitosan's reactive functional groups are amendable to chemical reaction. Modifying the material to show enhanced solubility, a greater range of application options and pH-sensitive targeting and others have been a major focus of chitosan research. This review describes the modifications of chitosan that have been made to improve its water solubility, pH sensitivity, and capacity to target chitosan derivatives. Applying the by-products of chitosan as antibacterial, in targeting, extended release and as delivery systems is also covered. The by-products of chitosan will be important and potentially useful in developing new biomedical drugs in time to come.

Pharmacological and phytochemical review of Acmella oleracea: a comprehensive analysis of its therapeutic potential

Acmella oleraceaL. (Asteraceae), commonly known as the toothache plant, is a tropical herb with significant therapeutic potential. Traditionally, it has been used for its analgesic and sialagogue properties, and it is known for its distinctive yellow flower crest. This review addresses current gaps in the understanding of its pharmacological properties and aims to provide a comprehensive analysis of its therapeutic potential. A thorough literature review was conducted using databases such as Google Scholar, ScienceDirect, and PubMed/MedLine. The findings indicate that A. oleraceacontains a variety of phytochemicals, including spilanthol, which exhibit diverse pharmacological activities such as antioxidant, anti-inflammatory, immunomodulatory, antinociceptive, pronociceptive, antibacterial, antifungal, antidiabetic, diuretic, and vasorelaxant effects. The results highlight the significant medicinal potential ofA. oleraceawhile also identifying areas for further research, particularly regarding its toxicological impacts on humans and animals. This review aims to guide future studies on the health benefits and safety of this plant.

Correlation between Perturbation of Redox Homeostasis and Antibiofilm Capacity of Phytochemicals at Non-Lethal Concentrations

Biofilms are the multicellular lifestyle of microorganisms and are present on potentially every type of biotic or abiotic surface. Detrimental biofilms are generally targeted with antimicrobial compounds. Phytochemicals at sub-lethal concentrations seem to be an exciting alternative strategy to control biofilms, as they are less likely to impose selective pressure leading to resistance. This overview gathers the literature on individual phytocompounds rather than on extracts of which the use is difficult to reproduce. To the best of our knowledge, this is the first review to target only individual phytochemicals below inhibitory concentrations against biofilm formation. We explored whether there is an overall mechanism that can explain the effects of individual phytochemicals at sub-lethal concentrations. Interestingly, in all experiments reported here in which oxidative stress was investigated, a modest increase in intracellular reactive oxygen species was reported in treated cells compared to untreated specimens. At sub-lethal concentrations, polyphenolic substances likely act as pro-oxidants by disturbing the healthy redox cycle and causing an accumulation of reactive oxygen species.