Antibiotic-resistant Pathogenic Bacteria Research Articles

Clinical Situation, Species Distribution, and Antibiotic Resistance of Pathogenic Bacteria and Fungi in 626 Cases of Vulvovaginitis in Hangzhou, China.

Female vulvovaginitis was one of the most common gynecological diseases. It had a great negative impact on their work and quality of life. This retrospective study evaluated the clinical and laboratory data of patients with vulvovaginitis in Hangzhou, China. To analyze the clinical situation, species distribution and antibiotic resistance of pathogenic fungi and bacteria in 626 cases of vulvovaginitis in Hangzhou. Microorganism culture, identification, and antibiotic susceptibility testing were conducted. The study aimed to provide a theoretical value for an effective treatment of vulvovaginitis. In total, 626 outpatients and inpatients diagnosed with vulvovaginitis were selected from January 2018 to January 2023. Data of all the patients were collected from the hospital's electronic medical records. Vaginal secretion was collected for testing and SPSS 25.0 software was used to perform statistical analysis. A total of 626 strains of fungi, Gram-positive, and -negative bacteria were detected. Clinical situations of patients infected with the top five pathogenic fungi and bacteria were analyzed. Pathogenic fungi and bacteria were slightly different in each age group and in each onset time group. The results of antibiotic susceptibility testing showed that the resistance rates of itraconazole and fluconazole were high and Gram- negative and -positive bacteria were multidrug resistant. Gram-negative bacteria were more sensitive to carbenicillins and compound antibiotics, while Gram-positive bacteria were sensitive to rifampicin and daptomycin. MRSA and non vancomycin-resistant strains were detected. Fungi and bacteria were usually detected as pathogenes in patients with vulvovaginitis in Hangzhou. Some factors, such as age and onset time, often affected the incidence. Pathogenic fungi and bacteria were resistant to some common antibiotics, and clinical treatments should be carried out in a timely and reasonable manner according to the results of antibiotic susceptibility testing.

An effective antibiofilm strategy based on bacteriophages armed with silver nanoparticles

The emerging antibiotic resistance in pathogenic bacteria is a key problem in modern medicine that has led to a search for novel therapeutic strategies. A potential approach for managing such bacteria involves the use of their natural killers, namely lytic bacteriophages. Another effective method involves the use of metal nanoparticles with antimicrobial properties. However, the use of lytic phages armed with nanoparticles as an effective antimicrobial strategy, particularly with respect to biofilms, remains unexplored. Here, we show that T7 phages armed with silver nanoparticles exhibit greater efficacy in terms of controlling bacterial biofilm, compared with phages or nanoparticles alone. We initially identified a novel silver nanoparticle-binding peptide, then constructed T7 phages that successfully displayed the peptide on the outer surface of the viral head. These recombinant, AgNP-binding phages could effectively eradicate bacterial biofilm, even when used at low concentrations. Additionally, when used at concentrations that could eradicate bacterial biofilm, T7 phages armed with silver nanoparticles were not toxic to eukaryotic cells. Our results show that the novel combination of lytic phages with phage-bound silver nanoparticles is an effective, synergistic and safe strategy for the treatment of bacterial biofilms.

In vitro and in silico evaluation of anti-quorum sensing activity of marine red seaweeds-Portieria hornemannii and Halymenia dilatata

The bacterial cell communicates from one cell to another by binding Auto-Inducers to specific receptors and their virulence factors, which are all products of their expression system. Therefore, this pathogenesis is controlled by disrupting the signal-response system. The current study assesses three maritime red seaweeds, including Portieria hornemannii and Halymenia dilatata, for their anti-Quorum Sensing (QS) activity against four bacteria. Those opportunistic pathogens cause severe QS-dependent biofilm formation and other virulences. In vitro, the study showed that biofilm formation in S. aureus was inhibited with 43.3%, 55% in Acinetobacter sp, 48% in E. coli, and 39. 2 % in K. pneumoniae by red seaweed extracts. The EPS production was also highly inhibited in Acinetobacter sp. with 41 % more than other bacteria. The efflux pump expressions and QS-dependent swimming motility were also effectively reduced. The present study targets the receptor proteins to prevent from binding of QS signals. Correspondingly, the in silico research predicts the binding affinity of bioactive compounds of seaweed extracts to the QS receptor proteins. The Hexamethyl Cyclotrisiloxane, Benzo[h]quinoline, 2,4-dimethyl, and 5-Methyl-2-phenylindolizine compounds from H. dilatata, P. hornemannii, respectively, showed a higher binding affinity with receptor proteins such as AgrC (PDB ID: 4BXI) of S. aureus, SdiA (PDB ID:4LFU) of E. coli, Modelled SdiA protein of K. pneumoniae and Modelled AbaR protein of Acinetobacter sp. This study demonstrates the potential of seaweed against virulence and antibiotic resistance of pathogenic bacteria.

Antibacterial Activity of Ethanol Extract of Larch Sponge Fruiting Body

Antibiotic resistance in pathogenic bacteria is a worldwide problem. In recent years, there has been increasing interest in the evaluation of plants and fungi with antibacterial activity against various infectious agents. The antibacterial activity of ethanol extract of Laricifomes officinalis (Vill.) Kotl. et Pouzar (Polyporaceae) fruiting body was studied. Activity was assessed using the disk diffusion method. L.officinalis ethanol extract showed high activity against Yersinia pseudotuberculosis, as well as moderate activity against Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, and Staphylococcus aureus. Listeria monocytogenes were not sensitive to ethanol extract of the fruiting body of L.officinalis.

Nanoparticle-Mediated Plasmid Curing in Combating Antibiotic Resistance in Pathogenic Bacteria

Background: Nanotechnology has emerged as a pivotal domain in material science research with extensive applications across various sectors including biotechnology and medicine. Nanoparticles offer unique properties facilitating advancements in nanobiotechnology, particularly in nanomedicine, to combat bacterial infections and antibiotic resistance. This study aimed to determine the application of nanoparticles, specifically nano-TiO2, in treating plasmid-mediated antibiotic resistance in both Gram-negative and Gram-positive bacteria. Method: We evaluated antibiotic and nanomaterial sensitivity through disc diffusion and broth microdilution assays. Plasmid curing experiments were conducted using varying concentrations of nano-TiO2 and SDS as curing agents, followed by plasmid isolation and DNA extraction. The efficacy of nano-TiO2 in plasmid curing and DNA extraction was assessed, alongside the impact on bacterial growth and antibiotic resistance. Results: Results showed successful plasmid elimination with nano-TiO2 treatment, evidenced by the loss of plasmid DNA bands. Additionally, nano-TiO2 substantially enhanced DNA extraction efficiency and quality. The study indicated nano-TiO2's potential in combating antibiotic resistance by targeting plasmids, thereby presenting a novel approach in molecular biology techniques. Conclusion: In conclusion, this study underscores the promising role of nanoparticles in addressing bacterial infections and combating antibiotic resistance. Nano-TiO2 emerges as a valuable tool in DNA purification and plasmid curing, offering new avenues in molecular biology and antibiotic resistance research. However, further investigations are warranted to elucidate the broader implications of nanoparticles across diverse bacterial species and strains. These findings represent a significant step towards harnessing the potential of nanotechnology in combating antimicrobial resistance and advancing healthcare paradigms.

In vitro Antibacterial Activity of Ethanolic Tanao Si Kan Dang RD1 (Cannabis sativa L.) Extracts Against Human Antibiotic-Resistant Bacteria.

<b>Background and Objective:</b> A new strain of cannabis, <i>Cannabis sativa</i> L. Tanao Si Kan Dang RD1, has been approved and registered by the Rajamangala University of Technology Isan, Thailand. The <i>C. sativa</i> is acknowledged for its medicinal properties which demonstrated various therapeutic properties, such as anti-cancer and antibacterial activities. This study aimed to investigate the antibacterial activity of ethanolic extracts from the stems and leaves of the Tanao Si Kan Dang RD1 strain against seven antibiotic-resistant bacteria. <b>Materials and Methods:</b> The primary antibacterial activity of ethanolic Tanao Si Kan Dang RD1 extracts were determined using the disc diffusion method, while the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined using the broth microdilution method. <b>Results:</b> The largest inhibition zone, measuring 12 mm, was observed in leaf extracts against <i>Pseudomonas aeruginosa</i> 101. The lowest MIC, at 0.78 mg/mL, was obtained from stem extracts against <i>Stenotrophomonas maltophilia</i>. The lowest MBCs, at 12.5 mg/mL, were observed in leaf extracts against <i>Enterococcus faecalis</i>, <i>Acinetobacter baumannii</i>, multidrug-resistant <i>Klebsiella</i> <i>pneumoniae</i>, <i>Stenotrophomonas maltophilia</i> and <i>Pseudomonas aeruginosa</i> 101 and stem extracts against <i>Acinetobacter baumannii</i>, multidrug-resistant <i>Klebsiella pneumoniae</i>, <i>Stenotrophomonas maltophilia</i> and <i>Pseudomonas aeruginosa</i> 101. <b>Conclusion:</b> This study presents a novel finding regarding the antibacterial activity of ethanolic extracts from the leaves and stems of Tanao Si Kan Dang RD1 against antibiotic-resistant bacteria. The potential application of these cannabis plant extracts in the development of antibiotics capable of combating antibiotic-resistant pathogenic bacteria represents a promising strategy to address a significant global health concern.

Distribution characteristics of antibiotic resistance in direct-eating food and analysis of Citrobacter freundii genome and pathogenicity

Purpose This study aims to study the distribution characteristics of antibiotic resistance in direct-eating food and analysis of Citrobacter freundii genome and pathogenicity. Residual antibiotics and antibiotic resistance genes (ARGs) in the environment severely threaten human health and the ecological environment. The diseases caused by foodborne pathogenic bacteria are increasing daily, and the enhancement of antibiotic resistance of pathogenic bacteria poses many difficulties in the treatment of disease. Design/methodology/approach In this study, six fresh fruits and vegetable samples were selected for isolation and identification of culturable bacteria and analysis of antibiotic resistance. The whole genome of Citrobacter freundii isolated from cucumber was sequenced and analyzed by Oxford Nanopore sequencing. Findings The results show that 270 strains of bacteria were identified in 6 samples. From 12 samples of direct food, 2 kinds of probiotics and 10 kinds of opportunistic pathogens were screened. The proportion of Citrobacter freundii screened from cucumber was significantly higher than that from other samples, and it showed resistance to a variety of antibiotics. Whole genome sequencing showed that Citrobacter freundii was composed of a circular chromosome containing signal peptides, transmembrane proteins and transporters that could induce antibiotic efflux, indicating that Citrobacter freundii had strong adaptability to the environment. The detection of genes encoding carbohydrate active enzymes is more beneficial to the growth and reproduction of Citrobacter freundii in crops. A total of 29 kinds of ARGs were detected in Citrobacter freundii, mainly conferring resistance to fluoroquinolones, aminoglycosides, carbapenem, cephalosporins and macrolides. The main mechanisms are the change in antibiotic targets and efflux pumps, the change in cell permeability and the inactivation of antibiotics and the detection of virulence factors and ARGs, further indicating the serious risk to human health. Originality/value The detection of genomic islands and prophages increases the risk of horizontal transfer of virulence factors and ARGs, which spreads the drug resistance of bacteria and pathogenic bacteria more widely.

Nanoencapsulation of Zataria multiflora Essential Oil Containing Linalool Reduced Antibiofilm Resistance against Multidrug-resistant Clinical Strains

Background: The rise in antimicrobial resistance, caused by the production of biofilms by bacteria, is a significant concern in the field of healthcare. Nanoemulsion technology presents itself as a viable alternative in the quest to circumvent antibiotic resistance in pathogenic bacteria. Objective: The aim of this research was to form a sustainable nanoemulsion from Z. multiflora, and evaluate its antibacterial and anti-biofilm activities against the clinical isolates of Pseudomonas aeruginosa, Proteus mirabilis, and Staphylococcus aureus. Materials and Methods: Bioactive compounds of the oil were identified using GC-MS. Zataria multiflora essential oil (ZMEO) nanoemulsion was formulated as a water-dispersible nanoemulsion with a diameter of 184.88 ± 1.18 nm. The antibacterial and antibiofilm activities of the essential oil in both pure and nanoemulsion forms were assessed against pathogenic bacteria causing hospital-acquired infections using minimal inhibitory concentrations (MICs) and the microtiter method, respectively. Results: The main constituents were found to be linalool (78.66 %), carvacrol (14.25 %), and α- pinene (4.53%). Neither ZMEO nor the emulsified ZMEO showed any antimicrobial activity. However, ZMEO exhibited a low inhibition of biofilm formation by P. mirabilis, S. aureus, and P. aeruginosa. The most promising finding was that when the emulsified ZMEO was present at a concentration of 750 μg/mL, it significantly reduced biofilm formation by the aforementioned bacteria to 39.68% ± 2.62, 56.54% ± 3.35, and 59.60% ± 2.88, respectively. This result suggests that ZMEO nanoemulsion has the potential to effectively disrupt persistent biofilms and enhance the penetration of antimicrobial agents into the biofilm matrix. Conclusion: In conclusion, the study provides evidence supporting the use of ZMEO nanoemulsion as a potential treatment option for combating biofilm-related infections caused by Pseudomonas aeruginosa, Proteus mirabilis, and Staphylococcus aureus. Further research is warranted to explore the practical application of the proposed essential oil in clinical settings.

Antibacterial Potential of Symmetrical Twin-Drug 3,6-Diaminoxanthones.

Global health faces a significant issue with the rise of infectious diseases caused by bacteria, fungi, viruses, and parasites. The increasing number of multi-drug resistant microbial pathogens severely threatens public health worldwide. Antibiotic-resistant pathogenic bacteria, in particular, present a significant challenge. Therefore, there is an urgent need to identify new potential antimicrobial targets and discover new chemical entities that can potentially reverse bacterial resistance. The main goal of this research work was to create and develop a library of 3,6-disubstituted xanthones based on twin drugs and molecular extension approaches to inhibit the activity of efflux pumps. The process involved synthesizing 3,6-diaminoxanthones through the reaction of 9-oxo-9H-xanthene-3,6-diyl bis(trifluoromethanesulfonate) with various primary and secondary amines. The resulting 3,6-disubstituted xanthone derivatives were then tested for their in vitro antimicrobial properties against a range of pathogenic strains and their efficacy in inhibiting the activity of efflux pumps, biofilm formation, and quorum-sensing. Several compounds have exhibited effective antibacterial properties against the Gram-positive bacterial species tested. Xanthone 16, in particular, has demonstrated exceptional efficacy with a remarkable MIC of 11 µM (4 µg/mL) against reference strains Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212, and 25 µM (9 µg/mL) against methicillin-resistant S. aureus 272123. Furthermore, some derivatives have shown potential as antibiofilm agents in a crystal violet assay. The ethidium bromide accumulation assay pinpointed certain compounds inhibiting bacterial efflux pumps. The cytotoxic effect of the most promising compounds was examined in mouse fibroblast cell line NIH/3T3, and two monoamine substituted xanthone derivatives with a hydroxyl substituent did not exhibit any cytotoxicity. Overall, the nature of the substituent was critical in determining the antimicrobial spectra of aminated xanthones.

Metagenomic absolute quantification of antibiotic resistance genes and virulence factor genes-carrying bacterial genomes in anaerobic digesters

Sewage treatment works have been considered as hotspots for the dissemination of antibiotic resistance genes (ARGs). Anaerobic digestion (AD) has emerged as a promising approach for controlling the spread of ARGs while destroying biomass in sludge. Evaluating the impact of AD on ARG removal relies on the absolute quantification of ARGs. In this study, we quantified the ARG concentrations in both full-scale and lab-scale AD systems using a cellular spike-ins based absolute quantification approach. Results demonstrated that AD effectively removed 68 ± 18 %, 55 ± 12 %, and 57 ± 19 % of total ARGs in semi-continuous AD digesters, with solid retention times of 15, 20, and 25 days, respectively. The removal efficiency of total ARGs increased as the AD process progressed in the batch digesters over 40 days. A significant negative correlation was observed between digestion time and the concentrations of certain ARG types, such as beta-lactam, sulfonamide, and tetracycline. However, certain potential pathogenic antibiotic resistant bacteria (PARB) and multi-resistant high-risk ARGs-carrying populations robustly persisted throughout the AD process, regardless of the operating conditions. This study highlighted the influence of the AD process and its operating parameters on ARG removal, and revealed the broad spectrum and persistence of PARB in AD systems. These findings provided critical insights for the management of microbial hazards.

Effective binning of metagenomic contigs using contrastive multi-view representation learning

Contig binning plays a crucial role in metagenomic data analysis by grouping contigs from the same or closely related genomes. However, existing binning methods face challenges in practical applications due to the diversity of data types and the difficulties in efficiently integrating heterogeneous information. Here, we introduce COMEBin, a binning method based on contrastive multi-view representation learning. COMEBin utilizes data augmentation to generate multiple fragments (views) of each contig and obtains high-quality embeddings of heterogeneous features (sequence coverage and k-mer distribution) through contrastive learning. Experimental results on multiple simulated and real datasets demonstrate that COMEBin outperforms state-of-the-art binning methods, particularly in recovering near-complete genomes from real environmental samples. COMEBin outperforms other binning methods remarkably when integrated into metagenomic analysis pipelines, including the recovery of potentially pathogenic antibiotic-resistant bacteria (PARB) and moderate or higher quality bins containing potential biosynthetic gene clusters (BGCs).

Studies on the mechanisms of action and development of resistance to class II bacteriocins of Gram-positive bacteria

Bacteriocins are peptides or proteins produced by bacteria to kill or inhibit the growth of other bacteria inhabiting the same ecological niche. The growing interest in bacteriocins reflects their potential use in food preservation and treatment of infections caused by antibiotic-resistant pathogenic bacteria, among other applications. The number of published studies on the identification of new bacteriocin-producing strains is constantly increasing. At the same time, there is a noticeable lack of research describing the mechanisms of action of most newly identified bacteriocins, as well as the mechanisms leading to the development of resistance to these bacteriocins and cross-resistance to antibiotics. Detailed understanding of these issues will allow to develop guidelines ensuring the most effective, safe and long-term use of bacteriocins without the risk of resistance development. This work describes the main assumptions of the doctoral dissertation of Aleksandra Tymoszewska, which objectives were to characterize the mechanisms of action and of resistance to class II bacteriocins of Gram-positive bacteria. Using the model bacterium Lactococcus lactis, two groups of bacteriocins were examined: (i) garvicins Q, A, B and C, and BacSJ; and (ii) aureocin A53 (AurA53)- and enterocin L50 (EntL50)-like bacteriocins. Bacteriocins of group (i) have been shown to recognize susceptible cells and form pores in the cell membrane using a specific receptor, the mannose-specific phosphotransferase system (Man-PTS), and sensitive bacteria have been shown to acquire resistance to the these bacteriocins by modifying the structure of Man-PTS. On the other hand, the acquisition of resistance to group (ii) membrane-targeting and receptor-independent bacteriocins occurs through changes in the structure of the bacterial cell wall and membrane, which are induced by changes in the expression of proteins involved in lipid metabolism or components of the YsaCB-KinG-LlrG regulatory system. The results shed new light on previous views on the mechanisms of action of bacteriocins and open up opportunities for their further study.

Antibacterial activity of Ricinus communis plant extract against antibiotic resistant Helicobacter pylori and Gluconobacter oxydans isolated from fresh apple juices samples.

Bacteria were isolated from samples of Fresh Apple juices from shops of three different localities of Lahore. Analysis of samples from Liberty, Anarkali and Yateem khana Markets show different levels of contamination. There were pathogenic and non-pathogenic bacteria in all samples and were identified by the morphological and biochemical tests. Most of the plasmids of pathogenic bacteria were 4kb in their molecular size. Ribotyping of 16S ribosomal RNA gene sequencing was done to confirm Helicobacter pylori strain and Gluconobacter oxydans. The highest sensitivity of 210mm was shown by Enterobacter sp. against Aztheromysine disk (15µg) while Micrococcus sp. was highly resistant against all of the Antibiotics applied. The antibiotic resistance of pathogenic bacteria was also checked against Ricinus communis plant's extracts, all isolated bacterial pathogens were resistant but only, E.coli was inhibited at 300µl of the extracts. Presence of pathogenic bacteria in Apple juice samples was due to contamination of sewage water in drinking water while some of these pathogenic bacteria came from Apple's tree and other from store houses of fruits.

Phytobiotics: Response to Aquaculture as Substitute of Antibiotics and other Chemical Additives

The use of phytobiotics in aquafarming is nowadays an interesting topic because of its eco-friendly nature for the growth and antimicrobial performance of aqua livestock. Currently, the use of various antibiotics in aquaculture are restricted due to concerns about the potential development of antibiotic-resistant pathogenic bacteria. Overuse of antibiotics and other chemicals (like different disinfectants, chemicals, and preservatives) increases the potentiality of residual antibiotics and other chemicals being present in fish, fish flesh as well as in fishery products. Various phytobiotics from plant extracts or direct plant or animal resources have changed the present traditional scenario of using an antibiotic component against livestock performance in aquaculture. The bioactive compounds (like alkaloids, tannins, saponins, glycosides, terpenoids, phenolics, flavonoids, essential oils, or steroids) present in the phytobiotics act as an immunity booster, growth promoter, bio-appetizer, reproductive stimulator, bio-preservatives, etc. So, phytobiotics becoming an effective additive in aquaculture as a substitute for antibiotics and other chemical components. This present article is designed to provide a comprehensive and insightful overview of the current state of knowledge about phytobiotics that supports the need for sustainable and environmental friendly practices in the context of aquaculture.

Tire particles and its leachates: Impact on antibiotic resistance genes in coastal sediments

Tire particles (TPs), a significant group of microplastics, can be discharged into the coastal environments in various ways. However, our understanding of how TPs impact the antibiotic resistance and pathogenic risks of microorganisms in coastal sediments remains limited. In this study, we used metagenomics to investigate how TPs and their leachates could affect the prevalence of antibiotic resistance genes (ARGs), virulence factor genes (VFGs), and their potential risks to the living creatures such as soil invertebrates and microorganisms in the coastal sediments. We discovered that TP addition significantly increased the abundance and diversity of ARGs and VFGs in coastal sediments, with raw TPs displayed higher impacts than TP leachates and TPs after leaching on ARGs and VFGs. With increasing TP exposure concentrations, the co-occurrence frequency of ARGs and mobile genetic elements (MGEs) in the same contig also increased, suggesting that TPs could enhance the dispersal risk of ARGs. Our metagenome-based binning analysis further revealed that exposure to TPs increased the abundance of potentially pathogenic antibiotic-resistant bacteria (PARB). In addition, chemical additives of TP leachates (e.g., Zn and N-cyclohexylformamide) significantly affected the changes of ARGs in the pore water. In summary, our study provides novel insights into the adverse effects of TP pollutions on aggravating the dissemination and pathogenic risks of ARGs and PARB in the coastal environment.

Metallic Gallium Droplets Exhibit Poor Antibacterial Properties.

The rise of antibiotic resistance in pathogenic bacteria requires new therapeutics to be developed. Several metallic nanoparticles such as those made from silver, copper, and zinc have shown significant antibacterial activity, in part due to metal ion leaching. Ga3+ containing compounds have also been shown to have antibacterial properties. Accordingly, it is estimated that metallic Ga droplets may be antibacterial, and some studies to date have confirmed this. Here, multiple concentrations of Ga droplets were tested against the antibiotic resistant Gram-positive bacteria methicillin-resistantStaphylococcus aureus (MRSA) and the Gram-negative bacteria Pseudomonas aeruginosa (P. aeruginosa) Despite a high concentration (2 mg/mL), Ga droplets had only modest antibacterial activity against both bacteria after 24 h of interaction. Finally, we demonstrated that Ga droplets were easily functionalized through a galvanic replacement reaction to develop antibacterial particles with copper and silver demonstrating a total detectable reduction of MRSA and >96% reduction ofP. aeruginosa. Altogether, these results contradict previous literature and show that Ga droplets demonstrate no antibacterial activity at concentrations comparable to those of conventional antibiotics and well-established antibacterial nanomaterials and only modest antibacterial activity at very high concentrations. However, we demonstrate that their antibacterial activity can be easily enhanced by functionalization.

Studies on the airborne bacterial communities and antimicrobial resistance genes in duck houses based on metagenome and PCR analysis

The threat of antimicrobial resistance (AMR) is on the rise globally, especially with the development of animal husbandry and the increased demand for antibiotics. Livestock and poultry farms, as key sites for prevalence of antibiotic-resistant bacteria (ARB), can spread antimicrobial resistance genes (ARGs) through microbial aerosols and affect public health. In this study, total suspended particulate matter (TSP) and airborne culturable microorganisms were collected from duck houses in Tai'an, Shandong Province, and the bacterial communities and airborne ARGs were analyzed using metagenomics and PCR methods. The results showed that the bacterial communities in the air of duck houses were mainly Actinobacteria, Firmicutes, Proteobactria, Chlamydia, and Bcateroidetes at the phylum level. At the genus level, the air was dominated by Corynebacterium, Jeotgalicoccus, Staphylococcus, Brevibacterium, and Megacoccus, and contained some pathogenic bacteria such as Staphylococcus aureus, Corynebacterium diphtheriae, Klebsiella oxytoca, Acinetobacter baumannii, and Pseudomonas aeruginosa, which were also potential hosts for ARGs. The airborne ARGs were mainly macrolides (10.97%), penicillins (10.73%), cephalosporins (8.91%), streptozotocin (8.91%), and aminoglycosides (8.02%). PCR detected 27 ARGs in airborne culturable microorganisms, and comparative analysis between PCR and the metagenomic data revealed that a total of 9 ARGs were found to the same, including macrolides ErmA, ErmF, tetracyclines tetG, tetX, methicarbamazepines dfrA12, dfrA15, aminoglycosides APH3-VI, ANT2-Ⅰ, and sulfonamides sul2. Moreover, inhalation exposure modeling showed that the workers in duck houses inhaled higher concentrations of ARB, human pathogenic bacteria (HPB) and human pathogenic antibiotic-resistant bacteria (HPARB) than hospital workers. These results provide new insights into airborne microorganisms and ARGs in animal farms and lay the foundation for further study.

Novel Approaches for Combating Antibiotic Resistance in Pathogenic Bacteria

Antibiotic resistance has historically been mostly linked to the established mechanisms such target alteration, efflux pumps, and enzymatic inactivation. Also, the ability of bacteria to form biofilm is a formidable challenge to antibiotic efficacy. The extracellular matrix forms a protective barrier that renders most antibiotics ineffective, by limiting the interaction of the drug to its target. The emergence of novel antibiotic resistance mechanisms in pathogenic bacteria and its rapid propagation, by means of horizontal gene transfer or mobile genetic elements, is a constant challenge to the medical community. Bacteria are able to exchange genetic material, conferring to antibiotic resistance, at a startling rate that helps them adapt quickly. This is especially dangerous when antibiotics use is abused. The field of antibiotic resistance has experienced a notable shift in the past few years, owing to the identification of new resistance mechanisms utilized by pathogenic bacteria to impede the effectiveness of antibiotics. Over the past decade researchers have been rigorously studying these resistance mechanisms and working on strategies to overcome the ordeal. Notably, nanoparticles research targeting antibiofilm therapy to combat the antibiotic-resistance mechanisms has been truly innovative. There have also been positive reports on utilizing the CRISPR-Cas as a promising next-generation antibiotic that can be used to eliminate antibiotic resistant genes (ARGs) and resensitize bacterial populations to antibiotics. This review aims for a comprehensive understanding of the ongoing research on antibiotic resistance mechanisms and strategies to counter them, the remaining challenges for widespread clinical implementation and the importance of continued research.

Prevalence and distribution of antibiotic-resistant bacteria in the rhizosphere and rhizoplane of Suaeda salsa and Sporobolus alterniflorus grown in a pristine environment

Antibiotic-resistant bacteria (ARB) are believed to have originated from pristine soil environments. However, the prevalence of ARB in the root-associated niches of plants grown in these environments, as well as the distribution patterns of ARB in the rhizosphere and rhizoplane—two critical root-associated niches—remains elusive. In this study, we investigated the prevalence and distribution of ARB in the rhizosphere and rhizoplane of two main plant species, Suaeda salsa and Sporobolus alterniflorus, grown in a pristine environment in Yancheng, China, to address these questions. In total,181 bacterial strains were isolated from the root-associated niches of the two plant species. Strong niche differentiation of the bacterial community between the rhizosphere and rhizoplane was identified by both bacterial isolation- and high-throughput 16S ribosomal RNA gene (rDNA) sequencing-based analyses. In total, 69.06 % of the isolated bacterial strains were classified as ARB, with strains resistant to β-lactam class antibiotics and polymyxin being predominant. The relative abundance of ARB in the rhizoplane was higher than that in the rhizosphere for both plant species. Furthermore, variations were noted in the prevalence and distribution of ARB in the root-associated niches between the two species. Several pathogenic ARBs, such as Stenotrophomonas maltophilia, were identified among the isolated strains. A representative S. maltophilia strain was sequenced, and several important antibiotic resistance- and pathogenicity-associated genes were identified in its genome. These findings provide novel insights into the prevalence and distribution patterns of ARB in the rhizosphere and rhizoplane of plants grown in pristine environments.

Changes in community structure and microbiological risks in a small stream after receiving treated shale gas wastewater for two years

Discharge of treated shale gas wastewater is becoming prevalent in the Sichuan Basin in China, and the resulting potential environmental impacts have raised concern. In this study, the responses of microbial community in the receiving water to discharge of treated shale gas wastewater were assessed during a two-year study period, covering two wet seasons and one dry season. The results showed that the discharge of treated shale gas wastewater had no significant effects on alpha diversity in the two wet seasons, but had significant effects in the dry season after 15 months of discharge. Obvious changes in microbial community structure were observed in all three seasons at the downstream sites near the wastewater outfall, as compared to the control site. Multimetric indices indicated that the impacts of wastewater discharge on microbial ecosystem occurred with the extension of the discharge period. Moreover, special attention was given to the microbiological risks associated with antibiotic resistance genes (ARGs), virulence factor genes (VFGs), and pathogenic antibiotic resistant bacteria (PARBs) in the dry season in sediments of the receiving water. At downstream sites near the outfall, five subtypes of ARGs and seven VFGs showed a significant increase in relative abundance. Forty-two PARBs carrying ARGs and VFGs were detected, and three PARBs (Pseudomonas aeruginosa, Pseudomonas stutzeri and Pseudomonas fluorescens) increased obviously in relative abundance at the downstream site near the outfall. In conclusion, long-term wastewater discharge had effects on the microbial community, and limited microbiological risks existed in the receiving waters.