Antibiotics, Resistome and Resistance Mechanisms: A Bacterial Perspective

Antibiotic susceptibility of Vibrio parahaemolyticus isolated from prawns and oysters marketed in Zhanjiang, China

To evaluate the antibiotic susceptibility of Vibrio parahaemolyticus from prawns and oysters marketed in Zhanjiang, Guangdong, China. 84 strains of V. parahaemolyticus were isolated from prawns and oysters sampled from 9 major markets. The results showed that 84 V. parahaemolyticus strains had the highest rate of antibiotic resistance to oxytetracycline (69.05 %, 58/84) and the lowest rate of antibiotic resistance to enrofloxacin (1.19 %, 1/84), ciprofloxacin (4.76 %, 4/84) and norfloxacin (7.14 %, 6/84) in quinolone. Meanwhile, 96.42 % of the strains showed multiple antibiotic resistance (MAR). PCR results showed that the resistance phenotype was closely related to the antibiotic resistance genes and efflux pump genes (p < 0.01), and the efflux pump gene was the key causing MAR. The combination of antibiotics significantly eliminated multidrug resistance. In addition, efflux pump inhibitors also reduce MAR. This study may provide information on antibiotic susceptibility, antibiotic resistance and strategies for the control of V. parahaemolyticus.

Design, synthesis, biological evaluation and in silico study of N-(Pyrimidin-2-yl)alkyl/arylamide derivatives as quorum sensing inhibitors against Pseudomonas aeruginosa

The emergence of bacterial resistance to antimicrobial agents poses a serious threat to the effectiveness of treating bacterial illnesses. A major factor contributing to antimicrobial resistance is biofilm formation, driven by quorum sensing (QS). QS suppression inhibits the QS signaling pathway, obstructing cell-to-cell communication. This study focuses on N-(pyrimidin-2-yl)alkyl/arylamide derivatives, which were designed, synthesized, and characterized for their QS inhibitory effects. Among the synthesized compounds (3a-j), compounds 3b, 3d, and 3h exhibited the highest QS inhibitory activity, with inhibition zones of 17.66 ± 6.17, 14.00 ± 6.24, and 17.33 ± 0.66 mm, respectively. Further, molecular docking studies revealed binding affinities between - 8.4 and - 6.3 kcal/mol, indicating strong interactions with the target proteins. Moreover, molecular dynamic simulations confirmed the stability of the protein-ligand complexes for compounds 3b and 3 h. Additionally, in-silico methods were employed to predict the physicochemical properties of these molecules. Overall, these findings underscore the potential of N-(pyrimidin-2-yl)alkyl/arylamide derivatives as QS inhibitors, offering a new perspective for developing alternative antimicrobial therapies.

Fate and mitigation of antibiotics and antibiotic resistance genes in microbial fuel cell and coupled systems

Microbial fuel cells (MFCs), known for their low energy consumption, high efficiency, and environmental friendliness, have been widely utilized for removing antibiotics from wastewater. Compared to conventional wastewater treatment methods, MFCs produce less sludge while exhibiting superior antibiotic removal capacity, effectively reducing the spread of antibiotic resistance genes (ARGs). This study investigates 1) the mechanisms of ARGs generation and proliferation in MFCs; 2) the influencing factors on the fate and removal of antibiotics and ARGs; and 3) the fate and mitigation of ARGs in MFC and MFC-coupled systems. It is indicated that high removal efficiency of antibiotics and minimal amount of sludge production contribute the mitigation of ARGs in MFCs. Influencing factors, such as cathode potential, electrode materials, salinity, initial antibiotic concentration, and additional additives, can lead to the selection of tolerant microbial communities, thereby affecting the abundance of ARGs carried by various microbial hosts. Integrating MFCs with other wastewater treatment systems can synergistically enhance their performance, thereby improving the overall removal efficiency of ARGs. Moreover, challenges and future directions for mitigating the spread of ARGs using MFCs are suggested.

Arcobacteraceae: An Exploration of Antibiotic Resistance Featuring the Latest Research Updates

The Arcobacteraceae bacterial family includes species isolated from animals and related food products. Moreover, these species have been found in other ecological niches, including water. Some species, particularly Arcobacter butzleri and Arcobacter cryaerophilus, have been isolated from human clinical cases and linked to gastrointestinal symptoms. The presence of antibiotic-resistant strains is a concern for public health, considering the possible zoonoses and foodborne infections caused by contaminated food containing bacteria resistant to antibiotic treatments. This review aims to highlight the importance of antibiotic resistance in Arcobacter spp. isolates from several sources, including information about antibiotic classes to which this bacterium has shown resistance. Arcobacter spp. demonstrated a wide spectrum of antibiotic resistance, including several antibiotic resistance genes. Antibiotic resistance genomic traits include efflux pumps and mutations in antibiotic target proteins. The literature shows a high proportion of Arcobacter spp. that are multidrug-resistant. However, studies in the literature have primarily focused on the evaluation of antibiotic resistance in A. butzleri and A. cryaerophilus, as these species are frequently isolated from various sources. These aspects underline the necessity of studies focused on several Arcobacter species that could potentially be isolated from several sources.

Cellulosimicrobium Infections in Humans-A Narrative Review

Cellulosimicrobium species (formerly known as Oerskovia) are Gram-positive filamentous bacteria in the family Promicromonosporaceae and are more commonly found in sewage and soil. The present study aimed to identify all the published cases of Cellulosimicrobium species infections in the literature, describe the epidemiological, clinical, and microbiological characteristics, and provide data regarding its antimicrobial resistance, treatment, and outcomes. A narrative review was performed based on a PubMed and Scopus database search. In total, 38 studies provided data on 40 patients with infections by these species. The median age of patients was 52.5 years, and 55% were male. The most common infection types were bacteremia, infective endocarditis (IE), osteoarticular infections, peritoneal dialysis-associated peritonitis, and endophthalmitis. Antimicrobial resistance to vancomycin and the combination of trimethoprim and sulfamethoxazole was minimal, and vancomycin was the most commonly used antimicrobial for treating these infections. Overall mortality was minimal for all infections, except for bacteremia and IE, which carried high mortality rates.

Ewingella americana Infections in Humans-A Narrative Review

Ewingella americana is a Gram-negative rod that belongs to the order Enterobacterales and the family Yersiniaceae and was first identified in 1983 from 10 clinical strains in the United States of America. The present study aimed to identify all the published cases of E. americana in the literature, describe the epidemiological, clinical, and microbiological characteristics, and provide data regarding its antimicrobial resistance, treatment, and outcomes. A narrative review was performed based on a PubMed and Scopus databases search. In total, 16 studies provided data on 19 patients with infections by E. americana. The median age of the patients was 55 years, and 47.4% were male. The most common infections were those of the bloodstream, the respiratory tract, and the peritoneal cavity. Antimicrobial resistance to cephalosporins, aminoglycosides, and the combination of trimethoprim with sulfamethoxazole was minimal, and these were the most commonly used antimicrobials for treating these infections. No included study provided information on the genetic or molecular mechanism of this pathogen's antimicrobial resistance. The overall mortality was minimal, with only one patient with bacteremia succumbing to the infection. Further studies are needed to better understand this microorganism, its pathogenic potential in humans, and the genetic and molecular mechanisms underlying its antimicrobial resistance, for which very little evidence exists to date.

High prevalence of multidrug-resistant Pseudomonas aeruginosa carrying integron and exoA, exoS, and exoU genes isolated from burn patients in Ahvaz, southwest Iran: A retrospective study

Background

Pseudomonas aeruginosa as an opportunistic pathogen produces several virulence factors. This study evaluated the relative frequency of exoenzymes (exo) A, U and S genes and integron classes (I, II, and III) among multi-drug-resistant clinical P. aeruginosa isolates from burn patients in Ahvaz, southwest of Iran.

Methods

In this cross-sectional study P. aeruginosa isolates were recovered from 355 wound samples. The antimicrobial susceptibility test was done by disk agar diffusion method on Muller-Hinton agar according to the Clinical and Laboratory Standards Institute. MDR isolates were defined if they showed simultaneous resistance to 3 antibiotics. Extensively drug-resistant was defined as nonsusceptibility to at least one agent in all but two or fewer antimicrobial categories. The presence of class I, II, and III integrons and virulence genes was determined using a PCR assay on extracted DNA.

Results

Overall, 145 clinical P. aeruginosa isolates were confirmed with biochemical and PCR tests. Overall, 35% (52/145) of the isolates were taken from males and 64% (93/145) from female hospitalized burn patients. The highest resistance rates of P. aeruginosa isolates to antibiotics were related to piperacillin 59% (n = 86/145) and piperacillin-tazobactam 57% (n = 83/145). A total of 100% of isolates were resistant to at least one antibiotic. MDR and XDR P. aeruginosa had a frequency of 60% and 29%, respectively. The prevalence of integron classes I, II, and III in P. aeruginosa was 60%, 7.58%, and 3.44%, respectively. IntI was more common in MDR and XDR P. aeruginosa isolates. In addition, 70(48%) of P. aeruginosa isolates did not harbor integron genes. Besides, exoA, exoS, and exoU in P. aeruginosa had a frequency of 55%, 55%, and 56%, respectively.

Conclusion

It was found that P. aeruginosa as a potent pathogen with strong virulence factors and high antibiotic resistance in the health community can cause refractory diseases in burn patients.

RNA and protein biomarkers for detecting enhanced metabolic resistance to herbicides mesosulfuron-methyl and fenoxaprop-ethyl in black-grass (Alopecurus myosuroides)

BACKGROUND

The evolution of non-target site resistance (NTSR) to herbicides leads to a significant reduction in herbicide control of agricultural weed species. Detecting NTSR in weed populations prior to herbicide treatment would provide valuable information for effective weed control. While not all NTSR mechanisms have been fully identified, enhanced metabolic resistance (EMR) is one of the better studied, conferring tolerance through increased herbicide detoxification. Confirming EMR towards specific herbicides conventionally involves detecting metabolites of the active herbicide molecule in planta, but this approach is time-consuming and requires access to well-equipped laboratories.

RESULTS

In this study, we explored the potential of using molecular biomarkers to detect EMR before herbicide treatment in black-grass (Alopecurus myosuroides). We tested the reliability of selected biomarkers to predict EMR and survival after herbicide treatments in both reference and 27 field-derived black-grass populations collected from sites across the UK. The combined analysis of the constitutive expression of biomarkers and metabolism studies confirmed three proteins, namely, AmGSTF1, AmGSTU2 and AmOPR1, as differential biomarkers of EMR toward the herbicides fenoxaprop-ethyl and mesosulfuron in black-grass.

CONCLUSION

Our findings demonstrate that there is potential to use molecular biomarkers to detect EMR toward specific herbicides in black-grass without reference to metabolism analysis. However, biomarker development must include testing at both transcript and protein levels in order to be reliable indicators of resistance. This work is a first step towards more robust resistance biomarker development, which could be expanded into other herbicide chemistries for on-farm testing and monitoring EMR in uncharacterised black-grass populations. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Crucifer Lesion-Associated Xanthomonas Strains Show Multi-Resistance to Heavy Metals and Antibiotics

Copper resistance in phytopathogens is a major challenge to crop production globally and is known to be driven by excessive use of copper-based pesticides. However, recent studies have shown co-selection of multiple heavy metal and antibiotic resistance genes in bacteria exposed to heavy metal and xenobiotics, which may impact the epidemiology of plant, animal, and human diseases. In this study, multi-resistance to heavy metals and antibiotics were evaluated in local Xanthomonas campestris pv. campestris (Xcc) and co-isolated Xanthomonas melonis (Xmel) strains from infected crucifer plants in Trinidad. Resistance to cobalt, cadmium, zinc, copper, and arsenic (V) was observed in both Xanthomonas species up to 25 mM. Heavy metal resistance (HMR) genes were found on a small plasmid-derived locus with ~ 90% similarity to a Stenotrophomonas spp. chromosomal locus and a X. perforans pLH3.1 plasmid. The co-occurrence of mobile elements in these regions implies their organization on a composite transposon-like structure. HMR genes in Xcc strains showed the lowest similarity to references, and the cus and ars operons appear to be unique among Xanthomonads. Overall, the similarity of HMR genes to Stenotrophomonas sp. chromosomal genomes suggest their origin in this genus or a related organism and subsequent spread through lateral gene transfer events. Further resistome characterization revealed the presence of small multidrug resistance (SMR), multidrug resistance (MDR) efflux pumps, and bla (Xcc) genes for broad biocide resistance in both species. Concurrently, resistance to antibiotics (streptomycin, kanamycin, tetracycline, chloramphenicol, and ampicillin) up to 1000 µg/mL was confirmed.

Analysis of the Frequency, Antibiotic Susceptibility, and Related Genes among Foodborne Pathogenic Bacteria Isolated from Hospital Refrigerators in Tehran, Iran

Background

Hospital refrigerators as essential food storage can be important source of food contamination. We aimed to investigate the frequency and antibiotic susceptibility of the pathogenic bacteria in three hospital refrigerators in Tehran.

Methods

This study was performed on 254 samples, collected from 60 refrigerators of the various wards of three hospitals, A, B, and C, in Tehran, Iran from 2020 to 2021. Following isolation and identification of isolates, the antibiotic susceptibility pattern was determined. PCR-based assays were used to screen the presence of antibiotic resistance genes of resistant isolates.

Results

From 254 collected samples, 236 samples (92.9%) were contaminated. Most strains were isolated from refrigerators with poorly cleaned, temperatures above 8 °C in non-critical wards. Most bacteria belonging to Enterobacteriaceae (68.8%), followed by Staphylococcus (11.9%), and Enterococcus (10.6%), while the frequency of non-Enterobacteriaceae isolates was 8.9%. The highest antibiotic resistant bacteria were in extended spectrum beta-lactamase (ESBL) 9.7%, vancomycin-resistant enterococci (VRE) 5.3%, methicillin-resistant S. epidermidis (MRSE) 0.4%, and methicillin-resistant S. aureus (MRSA) 0.4%, respectively. The bla OXA-48, bla CTX, and bcla TEM genes were found only in 10% of Enterobacteriaceae isolates. The bla OXA-51 gene was found in all non-Enterobacteriaceae isolates. The vanA and mecA genes were detected in antibiotic-resistant Enterococcus and Staphylococcus.

Conclusion

Our findings suggests major concern about cross-contamination and the emergence of antibiotic-resistant isolates as a potential health threat with hospital refrigerators origin. More attention to hospital refrigerators cleaning is necessary to prevent foodborne diseases and nosocomial infections.

Biological roles of soil microbial consortium on promoting safe crop production in heavy metal(loid) contaminated soil: A systematic review

Heavy metal(loid) (HM) pollution of agricultural soils is a growing global environmental concern that affects planetary health. Numerous studies have shown that soil microbial consortia can inhibit the accumulation of HMs in crops. However, our current understanding of the effects and mechanisms of inhibition is fragmented. In this review, we summarise extant studies and knowledge to provide a comprehensive view of HM toxicity on crop growth and development at the biological, cellular and the molecular levels. In a meta-analysis, we find that microbial consortia can improve crop resistance and reduce HM uptake, which in turn promotes healthy crop growth, demonstrating that microbial consortia are more effective than single microorganisms. We then review three main mechanisms by which microbial consortia reduce the toxicity of HMs to crops and inhibit HMs accumulation in crops: 1) reducing the bioavailability of HMs in soil (e.g. biosorption, bioaccumulation and biotransformation); 2) improving crop resistance to HMs (e.g. facilitating the absorption of nutrients); and 3) synergistic effects between microorganisms. Finally, we discuss the prospects of microbial consortium applications in simultaneous crop safety production and soil remediation, indicating that they play a key role in sustainable agricultural development, and conclude by identifying research challenges and future directions for the microbial consortium to promote safe crop production.

Skin secretions of Leptodactylidae (Anura) and their potential applications

The skin of anuran species is a protective barrier against predators and pathogens, showing also chemical defense by substances that represent a potential source for bioactive substances. This review describes the current chemical and biological knowledge from the skin secretions of Leptodactylidae species, one of the most diverse neotropical frog families. These skin secretions reveal a variety of substances such as amines (12), neuropeptides (16), and antimicrobial peptides (72). The amines include histamine and its methylated derivatives, tryptamine derivatives and quaternary amines. The peptides of Leptodactylidae species show molecular weight up to 3364 Da and ocellatins are the most reported. The peptides exhibit commonly glycine (G) or glycine-valine (GV) as C-terminal amino acids, and the most common N-terminal amino acids are glutamic acid (E), lysine (K), and valine (V). The substances from Leptodactylidae species have been evaluated against pathogenic microorganisms, particularly Escherichia coli and Staphylococcus aureus, and the most active peptides showed MIC of 1-15 µM. Furthermore, some compounds showed also pharmacological properties such as immunomodulation, treatment of degenerative diseases, anticancer, and antioxidant. Currently, only 9% of the species in this family have been properly studied, highlighting a large number of unstudied species such as an entire subfamily (Paratelmatobiinae). The ecological context, functions, and evolution of peptides and amines in this family are poorly understood and represent a large field for further exploration.

Complementary supramolecular drug associates in perfecting the multidrug therapy against multidrug resistant bacteria

The inappropriate and inconsistent use of antibiotics in combating multidrug-resistant bacteria exacerbates their drug resistance through a few distinct pathways. Firstly, these bacteria can accumulate multiple genes, each conferring resistance to a specific drug, within a single cell. This accumulation usually takes place on resistance plasmids (R). Secondly, multidrug resistance can arise from the heightened expression of genes encoding multidrug efflux pumps, which expel a broad spectrum of drugs from the bacterial cells. Additionally, bacteria can also eliminate or destroy antibiotic molecules by modifying enzymes or cell walls and removing porins. A significant limitation of traditional multidrug therapy lies in its inability to guarantee the simultaneous delivery of various drug molecules to a specific bacterial cell, thereby fostering incremental drug resistance in either of these paths. Consequently, this approach prolongs the treatment duration. Rather than using a biologically unimportant coformer in forming cocrystals, another drug molecule can be selected either for protecting another drug molecule or, can be selected for its complementary activities to kill a bacteria cell synergistically. The development of a multidrug cocrystal not only improves tabletability and plasticity but also enables the simultaneous delivery of multiple drugs to a specific bacterial cell, philosophically perfecting multidrug therapy. By adhering to the fundamental tenets of multidrug therapy, the synergistic effects of these drug molecules can effectively eradicate bacteria, even before they have the chance to develop resistance. This approach has the potential to shorten treatment periods, reduce costs, and mitigate drug resistance. Herein, four hypotheses are presented to create complementary drug cocrystals capable of simultaneously reaching bacterial cells, effectively destroying them before multidrug resistance can develop. The ongoing surge in the development of novel drugs provides another opportunity in the fight against bacteria that are constantly gaining resistance to existing treatments. This endeavour holds the potential to combat a wide array of multidrug-resistant bacteria.

Discovery of Melittin as Triple-Action Agent: Broad-Spectrum Antibacterial, Anti-Biofilm, and Potential Anti-Quorum Sensing Activities

The development of antibiotic-resistant microorganisms is a major global health concern. Recently, there has been an increasing interest in antimicrobial peptides as a therapeutic option. This study aimed to evaluate the triple-action (broad-spectrum antibacterial, anti-biofilm, and anti-quorum sensing activities) of melittin, a membrane-active peptide present in bee venom. The minimum inhibitory concentration and minimum bactericidal concentration of the melittin were determined using the microdilution method and agar plate counting. Growth curve analysis revealed that melittin showed a concentration-dependent antibacterial activity. Scanning electron microscope analysis revealed that melittin treatment altered the morphology. Confocal laser scanning microscope revealed that melittin increased the membrane permeability and intracellular ROS generation in bacteria, all of which contribute to bacterial cell death. In addition, the crystal violet (CV) assay was used to test the anti-biofilm activity. The CV assay demonstrated that melittin inhibited biofilm formation and eradicated mature biofilms. Biofilm formation mediated by quorum sensing (QS) plays a major role in this regard, so molecular docking and molecular dynamics analysis confirmed that melittin interacts with LasR receptors through hydrogen bonds, and further evaluates the anti-QS activity of melittin through the production of virulence factors (pyocyanin, elastase, and rhamnolipid), exopolysaccharides secretion, and bacterial motility, that may be the key to inhibiting the biofilm formation mechanism. The present findings highlight the promising role of melittin as a broad-spectrum antibacterial, anti-biofilm agent, and potential QS inhibitor, providing a new perspective and theoretical basis for the development of alternative antibiotics.

Performance of sewage sludge treatment for the removal of antibiotic resistance genes: Status and prospects

Wastewater treatment plants (WWTPs) receive wastewater containing antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs), which are predominant contributors to environmental pollution in water and soil. Of these sources, sludge is a more significant contributor than effluent. Knowing how sludge treatment affects the fate of ARGs is vital for managing the risk of these genes in both human and natural environments. This review therefore discusses the sources and transmission of ARGs in the environment and highlights the risks of ARGs in sludge. The effects of co-existing constituents (heavy metals, microplastics, etc.) on sludge and ARGs during treatment are collated to highlight the difficulty of treating sludge with complex constituents in ARGs. The effects of various sludge treatment methods on the abundances of ARGs in sludge and in soil from land application of treated sludge are discussed, pointing out that the choice of sludge treatment method should take into account various potential factors, such as soil and soil biology in subsequent land application. This review offers significant insights and explores the abundances of ARGs throughout the process of sludge treatment and disposal. Unintentional addition of antibiotic residues, heavy metals, microplastics and organic matter in sludge could significantly increase the abundance and reduce the removal efficiency of ARGs during treatment, which undoubtedly adds a barrier to the removal of ARGs from sludge treatment. The complexity of the sludge composition and the diversities of ARGs have led to the fact that no effective sludge treatment method has so far been able to completely eliminate the ecological risk of ARGs. In order to reduce risks resulting by transmission of ARGs, technical and management measures need to be implemented.

Fate and transport modelling for evaluating antibiotic resistance in aquatic environments: Current knowledge and research priorities

Antibiotics have revolutionised medicine in the last century and enabled the prevention of bacterial infections that were previously deemed untreatable. However, in parallel, bacteria have increasingly developed resistance to antibiotics through various mechanisms. When resistant bacteria find their way into terrestrial and aquatic environments, animal and human exposures increase, e.g., via polluted soil, food, and water, and health risks multiply. Understanding the fate and transport of antibiotic resistant bacteria (ARB) and the transfer mechanisms of antibiotic resistance genes (ARGs) in aquatic environments is critical for evaluating and mitigating the risks of resistant-induced infections. The conceptual understanding of sources and pathways of antibiotics, ARB, and ARGs from society to the water environments is essential for setting the scene and developing an appropriate framework for modelling. Various factors and processes associated with hydrology, ecology, and climate change can significantly affect the fate and transport of ARB and ARGs in natural environments. This article reviews current knowledge, research gaps, and priorities for developing water quality models to assess the fate and transport of ARB and ARGs. The paper also provides inputs on future research needs, especially the need for new predictive models to guide risk assessment on AR transmission and spread in aquatic environments.

Evaluation of loop-mediated isothermal amplification method for efficient detection of the periodontopathic bacteria Porphyromonas gingivalis

Background

Periodontitis is a multifactorial, polymicrobial oral inflammatory illness brought on by oral pathogens. Porphyromonas gingivalis is a Gram-negative, obligatory anaerobic, black-pigmented coccobacillus and is regarded as a primary etiological factor in the progression of periodontitis. Rapid, highly senstitive and specific detection methods are emerging. The present study aimed to evaluate the loop-mediated isothermal amplification (LAMP) technique for efficiently detecting P. gingivalis from subgingival plaque samples of chronic periodontitis patients.

Materials and Methods

This study included 50 subgingival plaque samples from patients suffering from chronic periodontitis. The DNA (Deoxyribonucleic acid) was extracted by the "modified proteinase K" method. A set of six primers, targeting the pepO gene of P. gingivalis, was used for conducting LAMP. The amplification was visualized by naked-eye detection and agarose electrophoresis. Conventional polymerase chain reaction (PCR) and real-time qantitative PCR (qPCR) were carried out by targeting the 16SrRNA (16S ribosomal ribonucleic acid) gene of P. gingivalis.

Results

The results showed that LAMP detected P. gingivalis in 40 out of 50 samples (80%). Whereas, qPCR and conventional PCR technique detected P. gingivalis in 38 (76%) and 33 (66%) samples respectively. The sensitivity and specificity of the LAMP method were 94.87% and 90.90%, respectively. With qPCR, the sensitivity and specificity were found to be 92.30% and 81.81%, respectively, whereas, with conventional PCR, it was found to be 76.92% and 72.72%, respectively.

Conclusion

LAMP is an efficient technique for quick, accurate, and reliable identification of P. gingivalis from subgingival plaque samples. The technique needs to be validated analytically, and further studies can be conducted by taking saliva and/or gingival crevicular fluid samples from periodontitis patients.

The Role of Stakeholders' Understandings in Emerging Antimicrobial Resistance: A One Health Approach

The increasing misuse of antibiotics in human and veterinary medicine and in agroecosystems and the consequent selective pressure of resistant strains lead to multidrug resistance (AMR), an expanding global phenomenon. Indeed, this phenomenon represents a major public health target with significant clinical implications related to increased morbidity and mortality and prolonged hospital stays. The current presence of microorganisms multi-resistant to antibiotics isolated in patients is a problem because of the additional burden of disease it places on the most fragile patients and the difficulty of finding effective therapies. In recent decades, international organizations like the World Health Organization (WHO) and the European Centre for Disease Prevention and Control (ECDC) have played significant roles in addressing the issue of AMR. The ECDC estimates that in the European Union alone, antibiotic resistance causes 33,000 deaths and approximately 880,000 cases of disability each year. The epidemiological impact of AMR inevitably also has direct economic consequences related not only to the loss of life but also to a reduction in the number of days worked, increased use of healthcare resources for diagnostic procedures and the use of second-line antibiotics when available. In 2015, the WHO, recognising AMR as a complex problem that can only be addressed by coordinated multi-sectoral interventions, promoted the One Health approach that considers human, animal, and environmental health in an integrated manner. In this review, the authors try to address why a collaboration of all stakeholders involved in AMR growth and management is necessary in order to achieve optimal health for people, animals, plants, and the environment, highlighting that AMR is a growing threat to human and animal health, food safety and security, economic prosperity, and ecosystems worldwide.

Design and synthesis of broad-spectrum antimicrobial amphiphilic peptidomimetics to combat drug-resistance

The gradual depletion of antibiotic discovery pipeline makes the antibiotic resistance a difficult clinical problem and a global health emergency. The membrane-active antimicrobial peptides (AMPs) attracted much attention due to a lower tendency to bacterial resistance than traditional antibiotics. However, some immanent drawbacks of AMPs may hamper their application in combating antibiotic resistance in the long run, such as susceptible to enzymatic degradation and low cell permeability. Herein, we report the design and synthesis of a novel series of amphiphilic peptidomimetics, from which we identified compounds that exhibited potent antimicrobial activity against a panel of clinically relevant Gram-positive and Gram-negative bacteria strains. The most potent compound 20 (SD-110-12) is able to kill intracellular bacterial pathogens and prevent the development of bacterial resistance under the tested conditions by targeting cell membranes. Additionally, compound 20 (SD-110-12) obtains good in vivo efficacy that is comparative to vancomycin by eradicating MRSA and suppressing inflammation in a mice infected skin wound model, demonstrating its promising therapeutic potential.

Ecopharmacology: Knowledge, Attitude, and Medication Disposal Practice Among Pharmacy Students

Background

Ecopharmacology, as a form of drug management for the environment, focuses on the impact of drugs on the environment. Pharmacists, and by extension pharmacy students, are expected to play an important role in ecopharmacology. Therefore, this study was conducted to determine the knowledge and attitude towards ecopharmacology and the practice of disposal of leftover or expired medicines among pharmacy students.

Methods

This was a descriptive cross-sectional study among pharmacy students in Northwestern Ethiopia. The study took place from May 1 to June 15, 2023. A self-administered questionnaire was used for data collection.

Results

Four hundred and forty-five students were included in the study. Only 91 (20%) of the students were aware of the term ecopharmacology, 27% knew that excretion from the human or animal body is the major route by which pharmaceutical agents enter the environment, and 42% were aware of the risk of increased antimicrobial resistance due to antibiotic residues in the environment. In addition, only 27% of respondents reported receiving information about the disposal of pharmaceuticals. The most common method of disposing of medications was throwing them away in household trash (61.8%).

Conclusion

Our results suggest that while most pharmacy students in Ethiopia have a positive attitude toward ecopharmacology, they do not know enough about ecopharmacology and dispose of their medicines poorly. More uniform education in ecopharmacology and pharmaceutical pollution might be warranted in the pharmacy curriculum.

Antimicrobial resistance in southeast Asian water environments: A systematic review of current evidence and future research directions

Antimicrobial resistance has been a serious and complex issue for over a decade. Although research on antimicrobial resistance (AMR) has mainly focused on clinical and animal samples as essential for treatment, the AMR situation in aquatic environments may vary and have complicated patterns according to geographical area. Therefore, this study aimed to examine recent literature on the current situation and identify gaps in the AMR research on freshwater, seawater, and wastewater in Southeast Asia. The PubMed, Scopus, and ScienceDirect databases were searched for relevant publications published from January 2013 to June 2023 that focused on antimicrobial resistance bacteria (ARB) and antimicrobial resistance genes (ARGs) among water sources. Based on the inclusion criteria, the final screening included 41 studies, with acceptable agreement assessed using Cohen's inter-examiner kappa equal to 0.866. This review found that 23 out of 41 included studies investigated ARGs and ARB reservoirs in freshwater rather than in seawater and wastewater, and it frequently found that Escherichia coli was a predominant indicator in AMR detection conducted by both phenotypic and genotypic methods. Different ARGs, such as blaTEM, sul1, and tetA genes, were found to be at a high prevalence in wastewater, freshwater, and seawater. Existing evidence highlights the importance of wastewater management and constant water monitoring in preventing AMR dissemination and strengthening effective mitigation strategies. This review may be beneficial for updating current evidence and providing a framework for spreading ARB and ARGs, particularly region-specific water sources. Future AMR research should include samples from various water systems, such as drinking water or seawater, to generate contextually appropriate results. Robust evidence regarding standard detection methods is required for prospective-era work to raise practical policies and alerts for developing microbial source tracking and identifying sources of contamination-specific indicators in aquatic environment markers.

One Earth: The Equilibrium between the Human and the Bacterial Worlds

Misuse and abuse of antibiotics on humans, cattle, and crops have led to the selection of multi-resistant pathogenic bacteria, the most feared 'superbugs'. Infections caused by superbugs are progressively difficult to treat, with a subsequent increase in lethality: the toll on human lives is predicted to reach 10 million by 2050. Here we review three concepts linked to the growing resistance to antibiotics, namely (i) the Resistome, which refers to the collection of bacterial genes that confer resistance to antibiotics, (ii) the Mobilome, which includes all the mobile genetic elements that participate in the spreading of antibiotic resistance among bacteria by horizontal gene transfer processes, and (iii) the Nichome, which refers to the set of genes that are expressed when bacteria try to colonize new niches. We also discuss the strategies that can be used to tackle bacterial infections and propose an entente cordiale with the bacterial world so that instead of war and destruction of the 'fierce enemy' we can achieve a peaceful coexistence (the One Earth concept) between the human and the bacterial worlds. This, in turn, will contribute to microbial biodiversity, which is crucial in a globally changing climate due to anthropogenic activities.

SHIP: identifying antimicrobial resistance gene transfer between plasmids

MOTIVATION

Plasmids are carriers for antimicrobial resistance (AMR) genes and can exchange genetic material with other structures, contributing to the spread of AMR. There is no reliable approach to identify the transfer of AMR genes across plasmids. This is mainly due to the absence of a method to assess the phylogenetic distance of plasmids, as they show large DNA sequence variability. Identifying and quantifying such transfer can provide novel insight into the role of small mobile elements and resistant plasmid regions in the spread of AMR.

RESULTS

We developed SHIP, a novel method to quantify plasmid similarity based on the dynamics of plasmid evolution. This allowed us to find conserved fragments containing AMR genes in structurally different and phylogenetically distant plasmids, which is evidence for lateral transfer. Our results show that regions carrying AMR genes are highly mobilizable between plasmids through transposons, integrons, and recombination events, and contribute to the spread of AMR. Identified transferred fragments include a multi-resistant complex class 1 integron in Escherichia coli and Klebsiella pneumoniae, and a region encoding tetracycline resistance transferred through recombination in Enterococcus faecalis.

AVAILABILITY AND IMPLEMENTATION

The code developed in this work is available at https://github.com/AbeelLab/plasmidHGT.

Antibiofilm mechanism of peppermint essential oil to avert biofilm developed by foodborne and food spoilage pathogens on food contact surfaces

Establishing efficient methods to combat bacterial biofilms is a major concern. Natural compounds, such as essential oils derived from plants, are among the favored and recommended strategies for combatting bacteria and their biofilm. Therefore, we evaluated the antibiofilm properties of peppermint oil as well as the activities by which it kills bacteria generally and particularly their biofilms. Peppermint oil antagonistic activities were investigated against Vibrio parahaemolyticus, Listeria monocytogenes, Pseudomonas aeruginosa, Escherichia coli O157:H7, and Salmonella Typhimurium on four food contact surfaces (stainless steel, rubber, high-density polyethylene, and polyethylene terephthalate). Biofilm formation on each studied surface, hydrophobicity, autoaggregation, metabolic activity, and adenosine triphosphate quantification were evaluated for each bacterium in the presence and absence (control) of peppermint oil. Real-time polymerase chain reaction, confocal laser scanning microscopy, and field-emission scanning electron microscopy were utilized to analyze the effects of peppermint oil treatment on the bacteria and their biofilm. Results showed that peppermint oil (1/2× minimum inhibitory concentration [MIC], MIC, and 2× MIC) substantially lessened biofilm formation, with high bactericidal properties. A minimum of 2.5-log to a maximum of around 5-log reduction was attained, with the highest sensitivity shown by V. parahaemolyticus. Morphological experiments revealed degradation of the biofilm structure, followed by some dead cells with broken membranes. Thus, this study established the possibility of using peppermint oil to combat key foodborne and food spoilage pathogens in the food processing environment.

Detection and Phylogenetic Analysis of Extended-Spectrum β-Lactamase (ESBL)-Genetic Determinants in Gram-Negative Fecal-Microbiota of Wild Birds and Chicken Originated at Trimmu Barrage

Extended-spectrum β-lactamases (ESBL) give rise to resistance against penicillin and cephalosporin antibiotics in multiple bacterial species. The present study was conducted to map genetic determinants and related attributes of ESBL-producing bacteria in three wild aquatic bird species and chickens at the "Trimmu Barrage" in district Jhang, Punjab province, Pakistan. To study the prevalence of ESBL-producing bacteria, a total of 280 representative samples were collected from wild bird species; cattle egrets (Bubulcus ibis), little egrets (Egretta garzetta) and common teals (Anas crecca) as well as from indigenous chickens (Gallus gallus domesticus) originating from a local wet market. The isolates were confirmed as ESBL producers using a double disc synergy test (DDST) and bacterial species were identified using API-20E and 20NE strips. A polymerase chain reaction (PCR) was used to detect ESBL genetic determinants and for genus identification via 16S rRNA gene amplification. A phenotypic antimicrobial susceptibility test was performed for ESBL-producing isolates against 12 clinically relevant antibiotics using the Kirby-Bauer disk diffusion susceptibility test. A phylogenetic tree was constructed for the sequence data obtained in this study and comparative sequence data obtained from GenBank. The overall prevalence of ESBL-producing bacteria was 34.64% (97/280). The highest percentage (44.28%; 31/70) of ESBL-producing bacteria was recovered from chickens (Gallus gallus domesticus), followed by little egrets (Egretta garzetta) (41.43%; 29/70), common teal (Anas crecca) (28.57%; 20/70) and cattle egrets (Bubulcus ibis) (24.28%; 17/70). Five different ESBL-producing bacteria were identified biochemically and confirmed via 16S rRNA gene sequencing, which included Escherichia coli (72; 74.23%), Enterobacter cloacae (11; 11.34%), Klebsiella pneumoniae (8; 8.25%), Salmonella enterica (4; 4.12%) and Pseudomonas aeruginosa (2; 2.06%). Based on PCR, the frequency of obtained ESBL genes in 97 isolates was blaCTX-M (51.55%), blaTEM (20.62%), blaOXA (6.18%) and blaSHV (2.06%). In addition, gene combinations blaCTX-M + blaTEM, blaTEM + blaOXA and blaCTX-M + blaSHV were also detected in 16.49%, 2.06% and 1.03% of isolates, respectively. The ESBL gene variation was significant (p = 0.02) in different bacterial species while non-significant in relation to different bird species (p = 0.85). Phylogenetic analysis of amino acid sequence data confirmed the existence of CTX-M-15 and TEM betalactamases. The average susceptibility of the antibiotics panel used was lowest for both Klebsiella pneumoniae (62.5% ± 24.42) and Salmonella enterica (62.5% ± 31.08) as compared to Enterobacter cloacae (65.90% ± 21.62), Pseudomonas aeruginosa (70.83% ± 33.42) and Escherichia coli (73.83% ± 26.19). This study provides insight into the role of aquatic wild birds as reservoirs of ESBL-producing bacteria at Trimmu Barrage, Punjab, Pakistan. Hence, active bio-surveillance and environment preservation actions are necessitated to curb antimicrobial resistance.

Supplementation of exogenous phytohormones for enhancing the removal of sulfamethoxazole and the simultaneous accumulation of lipid by Chlorella vulgaris

In this study, the phytohormone gibberellins (GAs) were used to enhance sulfamethoxazole (SMX) removal and lipid accumulation in the microalgae Chlorella vulgaris. At the concentration of 50 mg/L GAs, the SMX removal achieved by C. vulgaris was 91.8 % while the lipid productivity of microalga was at 11.05 mg/L d^-1, which were much higher than that without GAs (3.5 % for SMX removal and 0.52 mg/L d^-1 for lipid productivity). Supplementation of GAs enhanced the expression of antioxidase-related genes in C. vulgaris as a direct response towards the toxicity of SMX. In addition, GAs increased lipid production of C. vulgaris by up-regulating the expression of genes related to carbon cycle of microalgal cells. In summary, exogenous GAs promoted the stress tolerance and lipid accumulation of microalgae at the same time, which is conducive to improving the economic benefits of microalgae-based antibiotics removal as well as biofuel production potential.

Profiling of Antimicrobial Resistance Genes and Integron from Escherichia coli Isolates Using Whole Genome Sequencing

This study is designed to investigate Escherichia coli for the antibiotic resistance genes (ARGs) and integrons from healthy as well as diarrhoeic/diseased animals/birds' faecal samples. A total of eight samples were selected for the study; from each animal, two samples were taken, one from healthy animals/birds and one from diarrhoeic/diseased animals/birds. Antibiotic sensitivity testing (AST) and whole genome sequencing (WGS) was performed for selected isolates. The E. coli isolates showed resistance to moxifloxacin, followed by erythromycin, ciprofloxacin, pefloxacin, tetracycline, levofloxacin, ampicillin, amoxicillin, and sulfadiazine (4/8, 50.00% each). The E. coli isolates were 100% sensitive to amikacin, followed by chloramphenicol, cefixime, cefoperazone, and cephalothin. A total of 47 ARGs from 12 different antibiotic classes were detected among the eight isolates by WGS. The different classes of antibiotics included aminoglycoside, sulphonamide, tetracycline, trimethoprim, quinolone, fosfomycin, phenicol, macrolide, colistin, fosmidomycin, and multidrug efflux. The class 1 integrons were detected in 6/8 (75.00%) isolates with 14 different gene cassettes.

Secular trend analysis of antibiotic utilisation in some hospitals in Southern Sichuan from 2010 to 2020

In order to assess the effectiveness of the Special Antimicrobial Stewardship Campaign launched by Ministry of Health of China in 2011, this study focused on the effectiveness and trends in the clinical use of antimicrobial drugs in selected hospitals in Southern Sichuan, China. This study collected and analyzed antibiotic data from 9 hospitals in Southern Sichuanin 2010, 2015, and 2020, including the rate of antibiotic use, expense, the intensity of antibiotic use and antibiotic use during the type I incisions of perioperative period. After 10 years of continuous improvement, the utilization rate of antibiotics in outpatients of the 9 hospitals continued to decline and was controlled below 20% by 2020, while the utilization rate in inpatients also significantly decreased, most were controlled within 60%. The use intensity of antibiotics (DDD (defined daily doses) per 100 bed-days) decreased from an average of 79.95 in 2010 to 37.96 in 2020. The prophylactic use of antibiotics decreased significantly in type I incision. The proportion of use within 30 min-1 h before operation was significantly increased. After the special rectification and sustained development of the clinical application of antibiotics, the relevant indicators of antibiotics tend to be stable, indicating that this Administration of antimicrobial drugs is conducive to improving the level of rational clinical application of antibiotics.

The oral microbiota is a reservoir for antimicrobial resistance: resistome and phenotypic resistance characteristics of oral biofilm in health, caries, and periodontitis

BACKGROUND

Antimicrobial resistance (AMR) is an ever-growing threat to modern medicine and, according to the latest reports, it causes nearly twice as many deaths globally as AIDS or malaria. Elucidating reservoirs and dissemination routes of antimicrobial resistance genes (ARGs) are essential in fighting AMR. Human commensals represent an important reservoir, which is underexplored for the oral microbiota. Here, we set out to investigate the resistome and phenotypic resistance of oral biofilm microbiota from 179 orally healthy (H), caries active (C), and periodontally diseased (P) individuals (TRN: DRKS00013119, Registration date: 22.10.2022). The samples were analysed using shotgun metagenomic sequencing combined, for the first time, with culture technique. A selection of 997 isolates was tested for resistance to relevant antibiotics.

RESULTS

The shotgun metagenomics sequencing resulted in 2,069,295,923 reads classified into 4856 species-level OTUs. PERMANOVA analysis of beta-diversity revealed significant differences between the groups regarding their microbiota composition and their ARG profile. The samples were clustered into three ecotypes based on their microbial composition. The bacterial composition of H and C samples greatly overlapped and was based on ecotypes 1 and 2 whereas ecotype 3 was only detected in periodontitis. We found 64 ARGs conveying resistance to 36 antibiotics, particularly to tetracycline, macrolide-lincosamide-streptogramin, and beta-lactam antibiotics, and a correspondingly high prevalence of phenotypic resistance. Based on the microbiota composition, these ARGs cluster in different resistotypes, and a higher prevalence is found in healthy and caries active than in periodontally diseased individuals. There was a significant association between the resistotypes and the ecotypes. Although numerous associations were found between specific antibiotic resistance and bacterial taxa, only a few taxa showed matching associations with both genotypic and phenotypic analyses.

CONCLUSIONS

Our findings show the importance of the oral microbiota from different niches within the oral cavity as a reservoir for antibiotic resistance. Additionally, the present study showed the need for using more than one method to reveal antibiotic resistance within the total oral biofilm, as a clear mismatch between the shotgun metagenomics method and the phenotypic resistance characterization was shown.

Elevated levels of anthropogenic antibiotic resistance gene marker, sul1, linked with extreme fecal contamination and poor water quality in wastewater-receiving ponds

In several low- and middle-income countries, such as India, the rapid construction of toilets to combat open defecation has not been matched with adequate wastewater treatment, resulting in extreme fecal contamination of the receiving environments. The sewage-receiving surface water bodies, typically close to the residences, are a potential hotspot for disease transmission and antibiotic resistance. Water, soil, and sediment samples from seven wastewater-receiving ponds (WRPs) were analyzed for water quality, chlorophyll-a, fecal contamination (yccT for Escherichia coli), 16S rRNA gene copies, and anthropogenic antibiotic resistance gene markers-sul1 and intI1. These WRPs were contrasted with two ponds that did not directly receive sewage. The water quality in the WRPs was comparable to raw sewage (BOD: 210-380 mg/L; COD: 350-630 mg/L; total-N: 100-190 mg/L; and total-P: 6-21 mg/L), and the relative levels of the DNA marker of E. coli were very high (yccT: 0.1% to ∼100% of total bacterial count) indicating extreme fecal contamination. The relative levels of sul1 and intI1 were 1-3 orders of magnitude higher in WRPs (sul1: 0.32%-10% of total bacterial count; and intI1: 0.2%-5% of total bacterial count) compared to the ponds that did not receive sewage directly. The relative levels of sul1 correlated with the DNA marker for the fecal indicator, E. coli (p-value < 0.05; r = 0.50; Spearman's rank correlation), and poor water quality.

Recent Advances in Strategies to Combat Bacterial Drug Resistance: Antimicrobial Materials and Drug Delivery Systems

Bacterial infection is a common clinical disease. Antibiotics have saved countless lives since their discovery and are a powerful weapon in the fight against bacteria. However, with the widespread use of antibiotics, the problem of drug resistance now poses a great threat to human health. In recent years, studies have investigated approaches to combat bacterial resistance. Several antimicrobial materials and drug delivery systems have emerged as promising strategies. Nano-drug delivery systems for antibiotics can reduce the resistance to antibiotics and extend the lifespan of novel antibiotics, and they allow targeting drug delivery compared to conventional antibiotics. This review highlights the mechanistic insights of using different strategies to combat drug-resistant bacteria and summarizes the recent advancements in antimicrobial materials and drug delivery systems for different carriers. Furthermore, the fundamental properties of combating antimicrobial resistance are discussed, and the current challenges and future perspectives in this field are proposed.

Design and Synthesis of Novel Antimicrobial Agents

The necessity for the discovery of innovative antimicrobials to treat life-threatening diseases has increased as multidrug-resistant bacteria has spread. Due to antibiotics' availability over the counter in many nations, antibiotic resistance is linked to overuse, abuse, and misuse of these drugs. The World Health Organization (WHO) recognized 12 families of bacteria that present the greatest harm to human health, where options of antibiotic therapy are extremely limited. Therefore, this paper reviews possible new ways for the development of novel classes of antibiotics for which there is no pre-existing resistance in human bacterial pathogens. By utilizing research and technology such as nanotechnology and computational methods (such as in silico and Fragment-based drug design (FBDD)), there has been an improvement in antimicrobial actions and selectivity with target sites. Moreover, there are antibiotic alternatives, such as antimicrobial peptides, essential oils, anti-Quorum sensing agents, darobactins, vitamin B6, bacteriophages, odilorhabdins, 18β-glycyrrhetinic acid, and cannabinoids. Additionally, drug repurposing (such as with ticagrelor, mitomycin C, auranofin, pentamidine, and zidovudine) and synthesis of novel antibacterial agents (including lactones, piperidinol, sugar-based bactericides, isoxazole, carbazole, pyrimidine, and pyrazole derivatives) represent novel approaches to treating infectious diseases. Nonetheless, prodrugs (e.g., siderophores) have recently shown to be an excellent platform to design a new generation of antimicrobial agents with better efficacy against multidrug-resistant bacteria. Ultimately, to combat resistant bacteria and to stop the spread of resistant illnesses, regulations and public education regarding the use of antibiotics in hospitals and the agricultural sector should be combined with research and technological advancements.

Antibiotic-resistant bacteria in bovine milk in India

Antibiotic resistance (ABR) is a global issue that draws the attention of all healthcare experts in the veterinary and medical fields. Of various factors, indiscriminate and unregulated antibiotic usage in the animals reared for food production, especially in cows and buffaloes suffering from mastitis, contribute significantly to the rising incidence of resistant bacteria. A literature survey reveals the spread of resistant strains of mastitis-causing bacteria, like Staphylococcus aureus and Escherichia coli, to humans. In addition, antibiotic residues detected in milk samples against all major groups of antibiotics are likely to enter the human body through the food chain and aggravate the condition. The cumulative effects of ABR have emerged as a silent killer. The benefits of systematic surveillance on ABR in India are yet to be available. Here is an attempt to understand the ABR burden in India associated with bovine milk and its mitigation strategies.

Prospecting Plant Extracts and Bioactive Molecules with Antimicrobial Activity in Brazilian Biomes: A Review

Antimicrobial resistance is currently one of the greatest threats to global health, food security, and development. In this aspect, medicinal plants have been studied to support the development of viable alternatives to prevent and treat infectious diseases. This study aimed to perform a review of the literature comprising the antimicrobial activity of vegetable species from Brazilian biomes. We selected 67 original scientific publications about extracts, fractions, or isolated molecules from plants in the Brazilian biomes, published between 2016 and 2020 in Pubmed, ScienceDirect, and Scielo. Data demonstrated that 98 plant species, especially collected in the Cerrado, Atlantic Forest, and Caatinga biomes, were tested against 40 fungi and 78 bacterial strains. Bioactive fractions of Eucalyptus globulus methanolic stump wood extract were active against Candida albicans and C. tropicalis (MIC 2.50 µg/mL). The catechin purified from Banisteriopsis argyrophylla leaves had activity against C. glabrata (MIC 2.83 µg/mL) and ethanolic extract obtained from Caryocar coriaceum bark and fruit pulp exhibited MIC of 4.1 µg/mL on Microsporum canis. For bacteria, compounds isolated from the dichloromethane extract of Peritassa campestris, lectin extracted from a saline extract of Portulaca elatior and essential oils of Myrciaria pilosa exhibited significant effect against Bacillus megaterium (MIC 0.78 µg/mL), Pseudomonas aeruginosa (MIC 4.06 µg/mL) and Staphylococcus aureus strains (MIC 5.0 µg/mL), respectively. The findings support the antimicrobial and bioeconomic potential of plants from Brazilian biodiversity and their promising health applications.

Exploring the potential of Rhizopus oryzae AUMC14899 as a novel endophytic fungus for the production of L-tyrosine and its biomedical applications

BACKGROUND

A significant threat to the public's health is the rise in antimicrobial resistance among numerous nosocomial bacterial infections. This may be a detriment to present initiatives to enhance the health of immune-compromised patients. Consequently, attention has been devoted to exploring new bioactive compounds in the field of drug discovery from endophytes. Therefore, this study is the first on the production of L-tyrosine (LT) as a promising bio-therapeutic agent from endophytic fungi.

RESULTS

A new endophytic fungal isolate has been identified for the first time as Rhizopus oryzae AUMC14899 from Opuntia ficus-indica (L.) and submitted to GenBank under the accession number MZ025968. Separation of amino acids in the crude extract of this fungal isolate was carried out, giving a higher content of LT, which is then characterized and purified. LT exhibited strong antibacterial and anti-biofilm activities against multidrug-resistant Gram-negative and Gram-positive bacteria. The recorded minimum inhibitory concentration (MIC) values ranged from 6 to 20 µg/ml. In addition, LT caused a strong reduction in biofilm formation and disrupted the preformed biofilm. Moreover, results indicated that LT supported cell viability, evidencing hemocompatibility and no cytotoxicity.

CONCLUSION

Our findings suggest that LT has potential as a therapeutic agent due to its potential antibacterial, anti-biofilm, hemocompatibility, and lack of cytotoxic activities, which may also increase the range of therapy options for skin burn infections, leading to the development of a novel fungal-based drug.

Chromate Removal by Enterobacter cloacae Strain UT25 from Tannery Effluent and Its Potential Role in Cr (VI) Remediation

An indigenous chromate-resistant bacterial strain isolated from tannery effluent was identified based on morphological, biochemical, and 16S rRNA gene sequencing, as Enterobacter cloacae UT25. It was found to resist heavy metal ions such as Cr (VI), Pb (II), Cu (II), Co (II), Ni (II), Hg (II), and Zn (II) and antibiotics. The strain was able to remove 89 and 86% chromate, after 24 h of incubation in a Luria-Bertani (LB) medium at an initial Cr (VI) concentration of 1000 and 1500 µg/ml, respectively. Minimum inhibitory concentration (MIC) was observed for chromate to be 80,000 and 1850 µg/ml, after 48 h of incubation in LB and acetate minimal media (AMM), respectively. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis showed discrete cells with intact and smooth cell walls and homogenous cytoplasm in the absence of metal stress, whereas chromate stress caused cell lysis and reduction in size, which was a characteristic response to Cr (VI) toxicity. Energy Dispersive X-Ray Spectroscopy (EDX) confirmed the adsorption of oxyanions to the cell wall which was one of the Cr (VI) removal mechanisms by the bacterium. Atomic Force Microscopy (AFM) micrographs of chromate-untreated and treated cells revealed Root Mean Square roughness (Rq) values of 16.25 and 11.26 nm, respectively, indicating less roughness in the presence of stress. The partial gene sequence of class 1 integrons (intI1) of strain UT25 showed 94% homology with intI1 gene of strain Enterobacter hormaechei strain ECC59 plasmid pECC59-1. The present analysis highlighted the potential of E. cloacae UT25 as a promissory bacterium that could be applied in removing chromate from polluted environments.

Sustainable conversion of antibiotic wastewater using microbial fuel cells: Energy harvesting and resistance mechanism analysis

In this study, tetracycline (TC) can be degraded in microbial fuel cells (MFCs) rapidly and efficiently for the synergistic effect of microbial metabolism and electrical stimulation. Different TC concentrations had different effects on the bioelectric performance of MFCs. Among them, 10 mg/L TC promoted the bioelectric properties of MFCs, the maximum power density reached 1744.4 ± 74.9 mW/cm². In addition, we demonstrated that Geobacter and Chryseobacterium were the dominant species in the anode biofilm, while Azoarcus and Pseudomonas were the prominent species in the effluent, and the initial TC concentration affected the microbial community composition. Furthermore, the addition of TC increased the relative abundance of aadA3, sul1, adeF, cmlA, and tetC in reactors, indicating that a single antibiotic could promote the expression of self-related resistance as well as the expression of other ARGs. Moreover, the presence of TC can increase the relative content of mobile genetic elements (MGEs) and greatly increase the risk of antibiotic resistance genes (ARGs) spreading. Meanwhile, network analysis revealed that some microorganisms (such as Acidovorax caeni, Geobacter soil, and Pseudomonas thermotolerans) and MGEs may be potential hosts for multiple ARGs.

Evaluation of cadmium tolerance and remediated efficacy of wild and mutated Enterobacter species isolated from potassium nitrate (KNO₃) processing unit contaminated soil

The purpose of this study was to find the most cadmium (Cd²⁺) tolerant and remediated bacteria isolate from KNO₃ processing unit contaminated soil. One isolate out of 19 isolates possessed excellent Cd²⁺ tolerance than others, which was recognized as Enterobacter hormaechei SFC3 through molecular characterization (16S rRNA sequencing). The identified E. hormaechei SFC3 contained 55% and 45% of GC and AT content, respectively. The wild and acridine orange mutated E. hormaechei SFC3 exhibited excellent resistance to Cd²⁺ up to the concentration of 1500 μg mL^-1. Furthermore, the wild E. hormaechei SFC3 and mutated E. hormaechei SFC3 showed 82.47% and 90.21% of Cd²⁺ remediation on 6th days of treatment respectively. Similarly, the Cd²⁺ tolerant wild and mutated E. hormaechei SFC3 showed considerable resistance to all the tested antibiotics. The findings indicate that E. hormaechei SFC3 isolated from KNO₃ processing unit contaminated soil is a promising candidate for microbial remediation of Cd²⁺ contamination.

The K-mer antibiotic resistance gene variant analyzer (KARGVA)

Characterization of antibiotic resistance genes (ARGs) from high-throughput sequencing data of metagenomics and cultured bacterial samples is a challenging task, with the need to account for both computational (e.g., string algorithms) and biological (e.g., gene transfers, rearrangements) aspects. Curated ARG databases exist together with assorted ARG classification approaches (e.g., database alignment, machine learning). Besides ARGs that naturally occur in bacterial strains or are acquired through mobile elements, there are chromosomal genes that can render a bacterium resistant to antibiotics through point mutations, i.e., ARG variants (ARGVs). While ARG repositories also collect ARGVs, there are only a few tools that are able to identify ARGVs from metagenomics and high throughput sequencing data, with a number of limitations (e.g., pre-assembly, a posteriori verification of mutations, or specification of species). In this work we present the k-mer, i.e., strings of fixed length k, ARGV analyzer - KARGVA - an open-source, multi-platform tool that provides: (i) an ad hoc, large ARGV database derived from multiple sources; (ii) input capability for various types of high-throughput sequencing data; (iii) a three-way, hash-based, k-mer search setup to process data efficiently, linking k-mers to ARGVs, k-mers to point mutations, and ARGVs to k-mers, respectively; (iv) a statistical filter on sequence classification to reduce type I and II errors. On semi-synthetic data, KARGVA provides very high accuracy even in presence of high sequencing errors or mutations (99.2 and 86.6% accuracy within 1 and 5% base change rates, respectively), and genome rearrangements (98.2% accuracy), with robust performance on ad hoc false positive sets. On data from the worldwide MetaSUB consortium, comprising 3,700+ metagenomics experiments, KARGVA identifies more ARGVs than Resistance Gene Identifier (4.8x) and PointFinder (6.8x), yet all predictions are below the expected false positive estimates. The prevalence of ARGVs is correlated to ARGs but ecological characteristics do not explain well ARGV variance. KARGVA is publicly available at https://github.com/DataIntellSystLab/KARGVA under MIT license.

Frequency of strains with multiple antibiotic resistance in the structure of opportunitistic pathogens

   Background. The problem of antibiotic resistance has remained significant for the medical community for more than half a century, since the first cases of resistance to penicillin were registered.   The aim. Analysis of the long-term dynamics of changes in the antibacterial resistance of microorganisms and the creation of a collection of multi-resistant strains of opportunistic microorganisms.   Materials and methods. The study included data from 3173 bacteriological samples of various loci of the human body for 2010 and 2020–2021. The sensitivity of isolated cultures was determined by the disk diffusion method to antimicrobial drugs of the following groups: penicillins, cephalosporins, fluoroquinolones, aminoglycosides, carbapenems, tetracyclines, macrolides, lincosamides, oxazolidinones, glycopeptides and others.   Results. In the general structure of conditionally pathogenic microorganisms, a significant increase in the frequency of isolation of multidrug-resistant representatives of the genus Staphylococcus by two or more times was observed in 2021 compared to 2010 and 2020. We also observed a significant increase in the proportion of multidrug-resistant Streptococcus spp. and non-fermenting gram-negative bacteria. These changes marked the beginning of the creation of a collection of conditionally pathogenic microorganisms with multiple antibacterial resistance. In the structure of multiresistant microorganisms included in the “Collection of human microbiota of the Irkutsk region”, the leading positions belong to Klebsiella pneumoniae (23.81 %), Escherichia coli (19.05 %) and Staphylococcus aureus (22.22 %).   Conclusion. Antibiotic resistance monitoring is an important measure to control the resistance of community-acquired and nosocomial (nosocomial) microorganisms both within a particular country and globally.

Plant Lectins: A Review on their Biotechnological Potential Toward Human Pathogens

The indiscriminate use of antibiotics is associated with the appearance of bacterial resistance. In light of this, plant-based products treating infections are considered potential alternatives. Lectins are a group of proteins widely distributed in nature, capable of reversibly binding carbohydrates. Lectins can bind to the surface of pathogens and cause damage to their structure, thus preventing host infection. The antimicrobial activity of plant lectins results from their interaction with carbohydrates present in the bacterial cell wall and fungal membrane. The data about lectins as modulating agents of antibiotic activity, potentiates the effect of antibiotics without triggering microbial resistance. In addition, lectins play an essential role in the defense against fungi, reducing their infectivity and pathogenicity. Little is known about the antiviral activity of plant lectins. However, their effectiveness against retroviruses and parainfluenza is reported in the literature. Some authors still consider mannose/ glucose/N-Acetylglucosamine binding lectins as potent antiviral agents against coronavirus, suggesting that these lectins may have inhibitory activity against SARS-CoV-2. Thus, it was found that plant lectins are an alternative for producing new antimicrobial drugs, but further studies still need to decipher some mechanisms of action.

Unraveling the impact and mechanism of antipyretic paracetamol on intergenera conjugative plasmid transfer

Antimicrobial resistance has been considered as a great threat to biosecurity and human health. And the transmission of antibiotic resistance genes (ARGs) by conjugated plasmid is a key factor in the prevalence of antimicrobial resistance. Paracetamol (PRC), one of nonopioid analgesics, is an extensively used antipyretic and mild analgesic worldwide available for numerous prescriptions. It was unclear whether PRC could promote the spread of ARGs. Here, it was demonstrated that PRC promoted intergenera conjugative plasmid transfer in an established conjugation model. Both donor and recipient strains treated by PRC emerged the variations of reactive oxygen species (ROS), SOS response and cell membrane permeability. Correspondingly, transcriptome analysis revealed that the gene expression involved in cell membrane permeability and SOS response was up-regulated significantly after PRC exposure. More directly, PRC also increased the expressions of conjugation related genes of trbG and trbP in donor. This study proved for the first time that PRC could enhance the intergenera conjugative plasmid transfer. Collectively, these findings manifested the potential threat associated with the existence of non-antibiotic substance PRC, which could provide an important insight into antimicrobial resistance spread.

Versatile lifestyles of Edwardsiella: Free-living, pathogen, and core bacterium of the aquatic resistome

Edwardsiella species in aquatic environments exist either as individual planktonic cells or in communal biofilms. These organisms encounter multiple stresses, include changes in salinity, pH, temperature, and nutrients. Pathogenic species such as E. piscicida, can multiply within the fish hosts. Additionally, Edwardsiella species (E. tarda), can carry antibiotic resistance genes (ARGs) on chromosomes and/or plasmids, that can be transmitted to the microbiome via horizontal gene transfer. E. tarda serves as a core in the aquatic resistome. Edwardsiela uses molecular switches (RpoS and EsrB) to control gene expression for survival in different environments. We speculate that free-living Edwardsiella can transition to host-living and vice versa, using similar molecular switches. Understanding such transitions can help us understand how other similar aquatic bacteria switch from free-living to become pathogens. This knowledge can be used to devise ways to slow down the spread of ARGs and prevent disease outbreaks in aquaculture and clinical settings.

Multidrug-Resistant Biofilms (MDR): Main Mechanisms of Tolerance and Resistance in the Food Supply Chain

Biofilms are mono- or multispecies microbial communities enclosed in an extracellular matrix (EPS). They have high potential for dissemination and are difficult to remove. In addition, biofilms formed by multidrug-resistant strains (MDRs) are even more aggravated if we consider antimicrobial resistance (AMR) as an important public health issue. Quorum sensing (QS) and horizontal gene transfer (HGT) are mechanisms that significantly contribute to the recalcitrance (resistance and tolerance) of biofilms, making them more robust and resistant to conventional sanitation methods. These mechanisms coordinate different strategies involved in AMR, such as activation of a quiescent state of the cells, moderate increase in the expression of the efflux pump, decrease in the membrane potential, antimicrobial inactivation, and modification of the antimicrobial target and the architecture of the EPS matrix itself. There are few studies investigating the impact of the use of inhibitors on the mechanisms of recalcitrance and its impact on the microbiome. Therefore, more studies to elucidate the effect and applications of these methods in the food production chain and the possible combination with antimicrobials to establish new strategies to control MDR biofilms are needed.

Bacitracin-Engineered BSA/ICG Nanocomplex with Enhanced Photothermal and Photodynamic Antibacterial Activity

To reduce the drug resistance of bacteria and enhance the antibacterial ability in bacterial infection therapy, we designed a new antibacterial nanoagent. In this system, a photosensitizer (indocyanine green, ICG) was loaded in bovine serum albumin (BSA) through hydrophobic-interaction-induced self-assembly to form stable BSA@ICG nanoparticles. Furthermore, a positively charged antibacterial peptide bacitracin (Bac) was physically immobilized onto the surface of BSA@ICG to generate a bacterial-targeted nanomedicine BSA@ICG@Bac through electrostatic interactions. Afterward, its photodynamic and photothermal activities were intensely evaluated. Moreover, its bactericidal efficiency was assessed via in vitro antibacterial assays and bacterial biofilm destruction tests. First, the obtained BSA@ICG@Bac showed both good singlet oxygen generation property and high photothermal conversion efficiency. In addition, it showed enhanced photodynamic and photothermal antibacterial capacities and biofilm-removing ability in vitro due to Bac modification. To sum up, our research provided an economic and less-time-consuming approach to preparing antibacterial nanomedicines with excellent antibacterial ability. Therefore, the prepared antibacterial nanomedicines have great potential to be utilized in clinical trials in the future.

Green Synthesis of Endolichenic Fungi Functionalized Silver Nanoparticles: The Role in Antimicrobial, Anti-Cancer, and Mosquitocidal Activities

Green nanotechnology is currently a very crucial and indispensable technology for handling diverse problems regarding the living planet. The concoction of reactive oxygen species (ROS) and biologically synthesized silver nanoparticles (AgNPs) has opened new insights in cancer therapy. The current investigation caters to the concept of the involvement of a novel eco-friendly avenue to produce AgNPs employing the wild endolichenic fungus Talaromyces funiculosus. The synthesized Talaromyces funiculosus–AgNPs were evaluated with the aid of UV visible spectroscopy, dynamic light scattering (DLS), Fourier infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The synthesized Talaromyces funiculosus–AgNPs (TF-AgNPs) exhibited hemo-compatibility as evidenced by a hemolytic assay. Further, they were evaluated for their efficacy against foodborne pathogens Staphylococcus aureus, Streptococcus faecalis, Listeria innocua, and Micrococcus luteus and nosocomial Pseudomonas aeruginosa, Escherichia coli, Vibrio cholerae, and Bacillus subtilis bacterial strains. The synthesized TF-AgNPs displayed cytotoxicity in a dose-dependent manner against MDA-MB-231 breast carcinoma cells and eventually condensed the chromatin material observed through the Hoechst 33342 stain. Subsequent analysis using flow cytometry and fluorescence microscopy provided the inference of a possible role of intracellular ROS (OH⁻, O⁻, H₂O₂, and O₂⁻) radicals in the destruction of mitochondria, DNA machinery, the nucleus, and overall damage of the cellular machinery of breast cancerous cells. The combined effect of predation by the cyclopoid copepod Mesocyclops aspericornis and TF-AgNPS for the larval management of dengue vectors were provided. A promising larval control was evident after the conjunction of both predatory organisms and bio-fabricated nanoparticles. Thus, this study provides a novel, cost-effective, extracellular approach of TF-AgNPs production with hemo-compatible, antioxidant, and antimicrobial efficacy against both human and foodborne pathogens with cytotoxicity (dose dependent) towards MDA-MB-231 breast carcinoma.

Antibiotic Abuse and Antimicrobial Resistance in Hospital Environment: A Retrospective Observational Comparative Study

Background and Objectives: Antimicrobial resistance represents a serious problem, and it may be life-threatening in the case of severe hospital-acquired infections (HAI). Antibiotic abuse and multidrug resistance (MDR) have significantly increased this burden in the last decades. The aim of this study was to investigate the distribution and susceptibility rates of five selected bacterial species (E. coli, K. pneumoniae, P. aeruginosa, S. aureus and E. faecium) in two healthcare settings located in the Apulia region (Italy). Materials and Methods: Setting n.1 was a university hospital and setting n.2 was a research institute working on oncological patients. All the enrolled patients were diagnosed for bacterial HAI. The observation period was between August and September 2021. Clinical samples were obtained from several biological sources, in different hospital wards. Bacterial identification and susceptibility were tested by using the software VITEC 2 Single system. Results: In this study, a higher incidence of multi-drug-resistant K. pneumoniae was reported (42,2% in setting n.1 and 50% in setting n.2), with respect to the Italian 2019 statistics report (30.3%). All the isolates of E. faecium and S. aureus were susceptible to linezolid. All the bacterial isolates of P. aeruginosa and most of K. pneumoniae were susceptible to ceftazidime–avibactam. Amikacin and nitrofurantoin represented a good option for treating E. coli infections. Multidrug-resistant (MDR) P. aeruginosa, methicillin-resistant S. aureus (MRSA) and vancomycin-resistantE. faecium (VRE) had a lower incidence in the clinical setting, with respect to E. coli and K. pneumoniae. Conclusions: The data obtained in this study can support clinicians towards a rational and safe use of antibiotics for treating the infections caused by these resistant strains, to enhance the overall efficacy of the current antibiotic protocols used in the main healthcare environments.