Trends and Development in the Antibiotic-Resistance of Acinetobacter baumannii: A Scientometric Research Study (1991-2019)

Research hotspots and trends regarding microRNAs in hypertension: a bibliometric analysis

To investigate the research levels, hotspots, and development trends regarding microRNAs in hypertension, this study conducted a visual analysis of studies on miRNA in hypertension based on the Web of Science core collection database using CiteSpace and VOSviewer analysis software along with literature from 2005-2023 as information data. Using citation frequency, centrality, and starting year as metrics, this study analyzed the research objects. It revealed the main research bodies and hotspots and evaluated the sources of literature and the distribution of knowledge from journals and authors. Finally, the potential research directions for miRNAs in hypertension are discussed. The results showed that the research field is in a period of vigorous development, and scholars worldwide have shown strong interest in this research field. A comprehensive summary and analysis of the current research status and application trends will prove beneficial for the advancement of this field.

Cyanobacterial compound Tolyporphine K as an inhibitor of Apo-PBP (penicillin-binding protein) in A. baumannii and its ADME assessment

Antibiotic-resistant Acinetobacter baumannii, is a common pathogen found in hospital settings and has become nosocomial due to its high infection-causing tendency amongst ICU patients. The present study explores the cyanocompoundswhich were capable to inhibit the Penicillin Binding Protein of A. baumannii through molecular docking, ADMET, and molecular dynamicssimulation strategy. A database having structural and origin details was generated for 85 bioactive compounds in MS Excel. The 3-D structures weredownloaded from the PubChem database and minimized. The receptor protein was minimized and validated for structure correctness. The database was screened against the penicillin-binding protein of A. baumannii through PyRx software. The top 5 compounds including the control molecule werefurther redocked to the receptor molecule through Autodock Vina software. The molecule pose having the highest affinity was further subjected to 100ns MD- simulation and simultaneously the in-vitro activity of the methanol extract and hexane extract was checked through agar well diffusion assay.Docking studies indicate Tolyporphine K to be a lead molecule which was further assessed through Molecular dynamics and MM/PBSA. The in-silicoresults suggested that the protein-ligand complex was found to be stable over the 100 ns trajectory with a binding free energy of -8.56 Kcalmol-1. Theligand did not induce any major structural conformation in the protein moiety and was largely stabilized by hydrophobic interactions. The bioactivityscore and ADME properties of the compounds were also calculated. The in-vitro agar well diffusion assay showed a moderate zone of inhibition of12.33mm. The results indicate that the compound Tolyporphin- K could be a potential inhibitor of penicillin-binding protein in A. baumannii. Yet furtherwork needs to be done to have a more concrete basis for the pathway of inhibition.Communicated by Ramaswamy H. Sarma.

Bacillus thuringiensis pesticidal toxins: A global analysis based on a scientometric study (1980-2021)

Several studies have been conducted on Bacillus thuringiensis (Bt) pesticidal toxins due to their successful environmentally friendly biopesticide activity against various insect pest orders, protozoa, mites, and nematodes. However, no existing study has systematically examined the trends and evolution of research on Bt pesticidal toxins from a scientometric perspective. This study aimed to analyze the trends and hotspots of global research in this field. 5757 publications on Bt pesticidal toxins were extracted from the Web of Science Core Collection (WoS) from 1980 to 2021. Statistical and scientometric analyses were performed using Excel, CiteSpace, and VOSviewer visualization tools to evaluate research evolution, journal contribution and subject categories, contributing countries and institutions, highly influential references, and most used author keywords. The 5757 publications featured in 917 journals spanning 116 subject categories. The top 5 subject categories ranked as Entomology, Biotechnology & Applied Microbiology, Microbiology, Biochemistry & Molecular Biology, and Agriculture. Out of these publications, the USA contributed the most, with 1562 publications, 72,754 citations, and 46.58 average citations per paper (ACPP); however, Belgium had the highest (106.43) ACPP among the top 20 contributing countries. The Chinese Academy of Agricultural Sciences is the leading institution with 298 publications and 21.20 ACPP. The Pasteur Institute is ranked first (90.04) in terms of ACPP. Keywords analyses revealed that recent studies are inclined toward the evolution of insect resistance against Bt toxins. In future, studies related to the development of resistance mechanisms by insects against Bt pesticidal toxins and ways to overcome them will likely receive more attention. This study highlights the past and current situations and prospective directions of Bt pesticidal toxins-related research.

A Bibliometric Analysis of Research on Bacterial Persisters

Background

In the past two decades, the surge of research on bacterial persisters has been inspired as increasingly concerning about the frequent failure of antibiotics treatment. This study was aimed at presenting a bibliometric and visualized analysis of relative publications on bacterial persisters, which offered insights into the development and research trends of this field.

Methods

The Web of Science Core Collection and Ovid MEDLINE databases were utilized to retrieve relevant publications on bacterial persisters from 2001 to 2021. After manual selection, data including titles, authors, journals, author keywords, addresses, the number of citations, and publication years were subsequently extracted. The data analysis and visual mapping were conducted with Excel, SPSS, R studio, and VOSviewer.

Results

In this study, 1,903 relevant publications on bacterial persisters were included. During 2001-2021, there was an exponential growth in the quantity of publications. It was found that these studies were conducted by 7,182 authors from 74 different countries. The USA led the scientific production with the highest total number of publications (859) and citation frequency (52,022). The Antimicrobial Agents and Chemotherapy was the most influential journal with 113 relevant publications. The cooccurrence analysis revealed that studies on bacterial persisters focused on four aspects: "the role of persisters in biofilms," "clinical persistent infection," "anti-persister treatment," and "mechanism of persister formation."

Conclusion

In the past two decades, the global field of bacterial persisters has significantly increased. The USA was the leading country in this field. Mechanistic studies continued to be the future hotspots, which may be helpful to adopt new strategies against persisters and solve the problem of chronic infection in the clinic.

Interaction of lytic phage T1245 with antibiotics for enhancement of antibacterial and anti-biofilm efficacy against multidrug-resistant Acinetobacter baumannii

Biofilms associated with multidrug-resistant (MDR) Acinetobacter baumannii on medical devices remain a big clinical problem. Antibiotic susceptibility tests were performed with eight commonly employed antibiotics against clinical isolates. The effects of antibiotics in combination with well-characterized lytic phage T1245 were studied to assess their antibacterial and anti-biofilm efficacy. Ceftazidime, colistin, imipenem, and meropenem significantly reduced bacterial density up to approximately 80% when combined with phage T1245, compared with control. Phage T1245 in combination with ceftazidime, colistin, and meropenem at subinhibitory concentrations demonstrated significant reduction in biomass and bacterial viability of 3-day established biofilms, compared with antibiotic alone. In addition, electron microscopy further confirmed the disruption of biofilm structure and cell morphology upon treatment with phage T1245 and antibiotics, including ceftazidime, colistin, and meropenem. Combined treatment of phage T1245 with these antibiotics could be employed for the management of A. baumannii infections and eradication of the bacterial biofilms.

The top 100 cited studies on bacterial persisters: A bibliometric analysis

Background: Bacterial persisters are thought to be responsible for the recalcitrance and relapse of persistent infections, and they also lead to antibiotic treatment failure in clinics. In recent years, researches on bacterial persisters have attracted worldwide attention and the number of related publications is increasing. The purpose of this study was to better understand research trends on bacterial persisters by identifying and bibliometrics analyzing the top 100 cited publications in this field.

Methods: The Web of Science Core Collection was utilized to retrieve the highly cited publications on bacterial persisters, and these publications were cross-matched with Google Scholar and Scopus. The top 100 cited publications were identified after reviewing the full texts. The main information of each publication was extracted and analyzed using Excel, SPSS, and VOSviewer.

Results: The top 100 cited papers on bacterial persisters were published between 1997 and 2019. The citation frequency of each publication ranged from 147 to 1815 for the Web of Science Core Collection, 153 to 1883 for Scopus, and 207 to 2,986 for Google Scholar. Among the top 100 cited list, there were 64 original articles, 35 review articles, and 1 editorial material. These papers were published in 51 journals, and the Journal of Bacteriology was the most productive journal with 8 papers. A total of 14 countries made contributions to the top 100 cited publications, and 64 publications were from the United States. 15 institutions have published two or more papers and nearly 87% of them were from the United States. Kim Lewis from Northeastern University was the most influential author with 18 publications. Furthermore, keywords co-occurrence suggested that the main topics on bacterial persisters were mechanisms of persister formation or re-growth. Finally, “Microbiology” was the most frequent category in this field.

Conclusion: This study identified and analyzed the top 100 cited publications related to bacterial persisters. The results provided a general overview of bacterial persisters and might help researchers to better understand the classic studies, historical developments, and new findings in this field, thus providing ideas for further research.

Role of environmental stresses in elevating resistance mutations in bacteria: Phenomena and mechanisms

Mutations are an important origin of antibiotic resistance in bacteria. While there is increasing evidence showing promoted resistance mutations by environmental stresses, no retrospective research has yet been conducted on this phenomenon and its mechanisms. Herein, we summarized the phenomena of stress-elevated resistance mutations in bacteria, generalized the regulatory mechanisms and discussed the environmental and human health implications. It is shown that both chemical pollutants, such as antibiotics and other pharmaceuticals, biocides, metals, nanoparticles and disinfection byproducts, and non-chemical stressors, such as ultraviolet radiation, electrical stimulation and starvation, are capable of elevating resistance mutations in bacteria. Notably, resistance mutations are more likely to occur under sublethal or subinhibitory levels of these stresses, suggesting a considerable environmental concern. Further, mechanisms for stress-induced mutations are summarized in several points, namely oxidative stress, SOS response, DNA replication and repair systems, RpoS regulon and biofilm formation, all of which are readily provoked by common environmental stresses. Given bacteria in the environment are confronted with a variety of unfavorable conditions, we propose that the stress-elevated resistance mutations are a universal phenomenon in the environment and represent a nonnegligible risk factor for ecosystems and human health. The present review identifies a need for taking into account the pollutants' ability to elevate resistance mutations when assessing their environmental and human health risks and highlights the necessity of including resistance mutations as a target to prevent antibiotic resistance evolution.

Mapping Global Prevalence of Acinetobacter baumannii and Recent Vaccine Development to Tackle It

Acinetobacter baumannii is a leading cause of nosocomial infections that severely threaten public health. The formidable adaptability and resistance of this opportunistic pathogen have hampered the development of antimicrobial therapies which consequently leads to very limited treatment options. We mapped the global prevalence of multidrug-resistant A. baumannii and showed that carbapenem-resistant A. baumannii is widespread throughout Asia and the Americas. Moreover, when antimicrobial resistance rates of Acinetobacter spp. exceed a threshold level, the proportion of A. baumannii isolates from clinical samples surges. Therefore, vaccines represent a realistic alternative strategy to tackle this pathogen. Research into anti-A. baumannii vaccines have enhanced in the past decade and multiple antigens have been investigated preclinically with varying results. This review summarises the current knowledge of virulence factors relating to A. baumannii–host interactions and its implication in vaccine design, with a view to understanding the current state of A. baumannii vaccine development and the direction of future efforts.

In vivo Antibacterial Activity of Star Anise (Illicium verum Hook.) Extract Using Murine MRSA Skin Infection Model in Relation to Its Metabolite Profile

Introduction

Star anise fruits (Illicium verum Hook.) have been used as an important treatment in traditional Chinese medicine. The previous studies reported the activity of the non-polar fractions as potential sources of antibacterial metabolites, and little was done concerning the polar fractions of star anise.

Methods

The antibacterial activity of the star anise aqueous methanolic (50%) extract against multidrug-resistant Acinetobacter baumannii AB5057 and methicillin-resistant Staphylococcus aureus (MRSA USA300) was investigated in vitro (disc diffusion assay, minimum bactericidal concentration determination, anti-biofilm activity and biofilm detachment activity). The antibacterial activity was further tested in vivo using a murine model of MRSA skin infection. Ultra-performance liquid chromatography coupled to high-resolution mass spectrometry (UPLC/HRMS) approach was applied for the identification of the metabolites responsible for the antibacterial activity. The antioxidant potential was evaluated using five in vitro assays: TAC (total antioxidant capacity), DPPH, ABTS, FRAP (ferric reducing antioxidant power) and iron-reducing power.

Results

In vitro, star anise aqueous methanolic extract showed significant inhibition and detachment activity against biofilm formation by the multidrug-resistant and highly virulent Acinetobacter baumannii AB5057 and MRSA USA300. The topical application of the extract in vivo significantly reduced the bacterial load in MRSA-infected skin lesions. The extract showed strong antioxidant activity using five different complementary methods. More than seventy metabolites from different classes were identified: phenolic acids, phenylpropanoids, sesquiterpenes, tannins, lignans and flavonoids.

Conclusion

This study proposes the potential use of star anise polar fraction in anti-virulence strategies against persistent infections and for the treatment of staphylococcal skin infections as a topical antimicrobial agent. To our knowledge, our research is the first to provide the complete polar metabolome list of star anise in an approach to understand the relationship between the chemistry of these metabolites and the proposed antibacterial activity.