Combining antibiotics with silver nanoparticles: A potential treatment strategy against antimicrobial resistance

Growing resistance to currently approved antibiotics is posing serious concern worldwide. The multidrug-resistant organisms are a major cause of mortality and morbidity around the globe. The limited options to treat infections caused by resistant organism requires alternative strategies to increase the effectiveness of antibiotic for better clinical outcomes. Recent advances in nanotechnology have enabled the drugs to be used in nanoscale to increase the effectiveness of antibiotics. The use of nanoparticles to treat infectious diseases has a long history in the pharmaceutical market, and the versatility of these particles to incorporate various materials as carriers make it an attractive option to combat the current crisis of emerging antibacterial resistance. Silver, a metal with many medical applications, has inherent antimicrobial properties. Therefore, silver NPs are appearing as one of the best options to be used in combination with antibiotics to increase effectiveness against resistant bacteria. Here, we discuss the applications and mechanisms of silver NPs to treat microbial resistance in light of recent research.

Risk Assessment of Future Antibiotic Resistance—Eliciting and Modelling Probabilistic Dependencies Between Multivariate Uncertainties of Bug-Drug Combinations

The increasing impact of antibacterial resistance concerns various stakeholders, including clinicians, researchers and decision-makers in the pharmaceutical industry, and healthcare policy-makers. In particular, possible multidrug resistance of bacteria poses complex challenges for healthcare risk assessments and for pharmaceutical companies’ willingness to invest in research and development (R&D). Neglecting dependencies between uncertainties of future resistance rates can severely underestimate the systemic risk for certain bug-drug combinations. In this paper, we model the dependencies between several important bug-drug combinations’ resistance rates that are of interest for the United Kingdom probabilistically through copulas. As a commonly encountered challenge in probabilistic dependence modelling is the lack of relevant historical data to quantify a model, we present a method for eliciting dependence information from experts in a formal and structured manner. It aims at providing transparency and robustness of the elicitation results while also mitigating common cognitive fallacies of dependence assessments. Methodological robustness is of particular importance whenever elicitation results are used in complex decisions such as prioritising investments of antibiotics R&D.

Vegetables and Fruit as a Reservoir of β-Lactam and Colistin-Resistant Gram-Negative Bacteria: A Review

Antibacterial resistance is one of the 2019 World Health Organization’s top ten threats to public health worldwide. Hence, the emergence of β-lactam and colistin resistance among Gram-negative bacteria has become a serious concern. The reservoirs for such bacteria are increasing not only in hospital settings but in several other sources, including vegetables and fruit. In recent years, fresh produce gained important attention due to its consumption in healthy diets combined with a low energy density. However, since fresh produce is often consumed raw, it may also be a source of foodborne disease and a reservoir for antibiotic resistant Gram-negative bacteria including those producing extended-spectrum β-lactamase, cephalosporinase and carbapenemase enzymes, as well as those harboring the plasmid-mediated colistin resistance (mcr) gene. This review aims to provide an overview of the currently available scientific literature on the presence of extended-spectrum β-lactamases, cephalosporinase, carbapenemase and mcr genes in Gram-negative bacteria in vegetables and fruit with a focus on the possible contamination pathways in fresh produce.

An in vitro approach to combat multidrug resistance in Salmonella typhi and human colon cancer with Excoecaria agallocha L. extract

Background The incidence of antibacterial resistance and colon cancer is increasing in India. Antibacterial resistance and chemoresistance demand the need of developing herbal or natural chemotherapeutic agents. Our study thus, aims to determine the antibacterial and anticancer activities of the leaf extracts of the mangrove Excoecaria agallocha. Results Liquid chromatography–mass spectroscopy analysis of the ethanolic E. agallocha extracts revealed the presence of Bergenin. The plant extract fraction containing Bergenin had potent antibacterial action against a resistant strain of Salmonella typhi with an MIC value of 15.7 ± 0.04 µg/mL. Treatment of the bacteria with the plant extract made it moderately susceptible to the antibacterial drugs ampicillin, aztreonam, cefotaxime, chloramphenicol and imipenem. The plant extract caused membrane damage and disrupted the expression of a 33 kDa outer membrane protein (OmpA) in S. typhi. It was plausibly due to this mechanism of the plant extract that made the bacteria susceptible to the antibacterial drugs to a certain extent. Further, fluorescence microscopy analysis revealed the anticancer property of the extract against a human colon cancer (DLD-1) cell line by activation of Caspase-3followed by subsequent apoptosis and exhibited cytotoxicity against the cancerous cell line with an IC50 value of 17.99 ± 1.12 µg/mL. Caspase-3 activity was observed to increase in a dose-dependent manner as determined by spectrophotometric assays. Moreover, the expression of the metalloproteinase-7 (MMP-7) was significantly reduced in plant extract treated DLD-1 colon cancer cells. Conclusion The results indicate that E. agallocha is a novel source of Bergenin, and the plant extract fraction under study may be used in combination therapy along with antibacterial drugs to combat antibacterial resistance of S. typhi and also to alleviate the risks of colon cancers in human. However, further investigations may be undertaken for its therapeutic application and to explore its potential bioactivity against other bacterial strains and human cancer cell lines.

Antibacterial Properties of Quinoline Derivatives: A Mini-Review

Antibacterial resistance plays a serious risk to human health throughout the globe. Various labors have been adopted to fight this resistance, so it is essential to design and synthesize new agents for the treatment of multi-resistance pathogens. Quinolines and their derivatives are used as antibacterial properties against various gram-positive and negative bacteria. In this mini-review, wish to report the antibacterial properties of quinoline derivatives against various pathogens in the years 2019 and 2020.

STAPHYLOCOCCUS AUREUS RESISTANCE AGAINST CEPHALOSPORIN ANTIBIOTIC IN ADEN-YEMEN

The study was carried out to determine antibacterial resistance profiles of methicillin-resistant Staphylococcus aureus (MRSA), isolated from clinical samples (n: 352) of patients during the period, from January 2019 to July 2020 in five governmental and private medical laboratories of Aden governorate, Yemen. The results showed the percentage for resistance ratio is differentiated between samples and the category of cephalosporin antibiotic groups. The highest percentage of resistance was in the wound sample for Cefadroxil, Cefuroxime, and Ceftriaxone at (100%), in addition to 100% in the pus, CSF, and sputum samples for Ceftriaxone antibiotic. Moreover, Cefadroxil has 100 % of resistance in semen, ear, and sputum samples. However, the Staphylococcus aureus isolated from the pharyngeal sample not showed any resistance to all cephalosporin antibiotic groups.

Riverine antibacterial resistance gradient determined by environmental factors

Wastewater emission to surface waters is a major pathway for antibacterials and antibacterial-resistant bacteria. Polluted waterbodies such as rivers provide a reservoir for bacterial resistance. We studied water quality and bacterial antibacterial resistance along the subtropical Qishan River in Taiwan as a case study of environmental resistance spread in a pristine to rural area. Human settlement densities increased generally from pristine mountain sites to the more polluted lowlands generally. Accordingly, as a working hypothesis, we expected antibacterial resistance level to increase towards downstream. We collected sediment samples from 8 stations along the Qishan river and where the Qishan river reaches the Kaoping river. The samples were processed in the lab for bacteriological and physicochemical analysis. Antibacterial resistance was tested by disk diffusion and micro-dilution with ten common antibacterials. A comparison was made among the sites where isolates began to occur at the upstream (site 1–6) with the downstream, including site 7 (Qishan town), site 8 (wastewater treatment plant) and site 9 (Kaoping river). The results of multivariate analysis for bacteriological and physicochemical parameters showed increasing water pollution levels downstream of the Qishan river. Ten bacteria including Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Enterobacter sp., Acinetobacter sp., Staphylococcus spp. and Bacillus spp. were analyzed and tested in the study. Their percentage of occurrence varied at each site. The resistance level was determined from the growth inhibition zone diameter (disk diffusion) and the minimum inhibitory concentration (micro-dilution). The results indicated that antibacterial resistance was related to certain environmental factors. Besides, the usage pattern of different classes of antibacterials in different places could alter trends of their resistance. Bacteria were found with increased resistance to antibacterials used in agriculture through the downstream sites according to the results. The WWTP emitting wastewater was demonstrated to be a hotspot of resistance in aquatic environments. In conclusion, bacterial resistance against antibacterials from the Qishan river has become a potential public health threat. This study could assist authorities by providing a reference for water quality risk assessment and management in Kaohsiung city and southern Taiwan.

Riverine antibacterial resistance gradient determined by environmental factors

Wastewater emission to surface waters is a major pathway for antibacterials and antibacterial-resistant bacteria. Polluted waterbodies such as rivers provide a reservoir for bacterial resistance. We studied water quality and bacterial antibacterial resistance along the subtropical Qishan River in Taiwan as a case study of environmental resistance spread in a pristine to rural area. Human settlement densities increased generally from pristine mountain sites to the more polluted lowlands generally. Accordingly, as a working hypothesis, we expected antibacterial resistance level to increase towards downstream. We collected sediment samples from 8 stations along the Qishan river and where the Qishan river reaches the Kaoping river. The samples were processed in the lab for bacteriological and physicochemical analysis. Antibacterial resistance was tested by disk diffusion and micro-dilution with ten common antibacterials. A comparison was made among the sites where isolates began to occur at the upstream (site 1-6) with the downstream, including site 7 (Qishan town), site 8 (wastewater treatment plant) and site 9 (Kaoping river). The results of multivariate analysis for bacteriological and physicochemical parameters showed increasing water pollution levels downstream of the Qishan river. Ten bacteria including Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Enterobacter sp., Acinetobacter sp., Staphylococcus spp. and Bacillus spp. were analyzed and tested in the study. Their percentage of occurrence varied at each site. The resistance level was determined from the growth inhibition zone diameter (disk diffusion) and the minimum inhibitory concentration (micro-dilution). The results indicated that antibacterial resistance was related to certain environmental factors. Besides, the usage pattern of different classes of antibacterials in different places could alter trends of their resistance. Bacteria were found with increased resistance to antibacterials used in agriculture through the downstream sites according to the results. The WWTP emitting wastewater was demonstrated to be a hotspot of resistance in aquatic environments. In conclusion, bacterial resistance against antibacterials from the Qishan river has become a potential public health threat. This study could assist authorities by providing a reference for water quality risk assessment and management in Kaohsiung city and southern Taiwan.