Antibiotics Chloramphenicol Research Articles

Review Article on Typhoid Fever

Typhoid fever is primarily found in impoverished countries with inadequate sanitation on a global scale. In the United States, the incidence of typhoid fever has been steadily decreasing since 1900 due to improvements in sanitation and effective antibiotic treatments. While typhoid fever is widespread, 80% of cases occur in the Americas, the Caribbean, Oceania, Bangladesh, China, India, Indonesia, Laos, and Nepal. Each year, approximately 200,000 individuals succumb to typhoid fever, and 21.6 million people are infected with the disease. When treated, the chance of death is 0.2% and there are rarely long-term symptoms. Untreated typhoid fever can lead to fatality and persist for multiple weeks. Lasting complications may involve central nervous system damage. 54 percent of reported typhoid fever cases in the United States between 1999 and 2006 included. One can receive fluids and electrolytes via a vein. For the treatment of typhoid fever, the patient can receive an antibiotic and, in rare circumstances, steroid medications. When prescribed antibiotics, most patients start feeling better after two days, and fatalities are rare. Typhoid cases are generally treated with specific antibiotics such ciprofloxacin, ampicillin, or chloramphenicol. Important public health measures include proper water purification, proper waste disposal, and safeguarding the food supply from contamination. Typhoid carriers should not be permitted to handle food in any capacity. If treatment is not received, patients may have a fever for weeks or months, and up to 20% of them may pass away from infection-related problems. The hospital setting is where those with infections are treated.

Regional distribution differences of antibiotics in tropical marine aquaculture area: Insights into antibiotic management and risk assessment

In recent years, global demand for marine aquaculture products has led to a significant rise in antibiotic use, particularly in tropical coastal aquaculture areas However, research on antibiotic residues in these environments remains limited, hindering a comprehensive understanding of their environmental presence and associated risks. This study investigates the regional distribution, ecological risks, and sources of 44 antibiotics in seawater across four coastal aquaculture areas in Hainan island (Wenchang, Sanya, Danzhou, and Wanning). Among the 44 antibiotics tested across 42 sampling sites, all were detected with a 100 % detection rate. Antibiotics such as Trimethoprim (TMP), Sulfanitran (APNPS), Sulfaquinoxaline (SQ), Sulfadimethoxine (SDT), Chloramphenicol (CHP), and Florfenicol (FLO) were consistently detected across all sampling sites. Total concentrations of detected antibiotics ranged from 0 to 818.79 ng.L−1, with sulfonamide antibiotics ranging from 0 to 629.49 ng.L−1, chloramphenicol antibiotics from 0 to 87.39 ng.L−1, tetracyclines from 0 to 221.39 ng.L−1, and fluoquinolones from 0 to 272.08 ng.L−1. The highest levels of antibiotic pollution were observed at the W5 sampling site in Wenchang, attributed to aquaculture wastewater discharge, while no antibiotics were found at D12 in Danzhou. In these regions, source analysis identified aquaculture and domestic sewage as the primary contributors to antibiotic pollution in these regions. Correlation analysis with environmental factors revealed significant influences of factors such as SAL, kPa, TN, SPC, and pH on sulfonamide and chloramphenicol antibiotics. Health risk assessment indicated moderate to high risks to aquatic organisms from antibiotics like NOR, CIP, ENR, OFL, TMP, and SMX in the study areas, underscoring the need for preventive measures, stricter regulation of antibiotic use, and enhanced ecological risk monitoring in aquaculture regions. This study provides critical insights into antibiotic contamination in Hainan's coastal aquaculture areas, highlighting the urgent need for further research into the occurrence and ecological impacts of these emerging pollutants in marine environments.

Simultaneous detection of enrofloxacin and chloramphenicol antibiotics using surface-enhanced Raman spectroscopy combined with triangular silver nanoplates

The emergence of antibiotic residues in the environment and food requires the development of sensitive and selective detection methods for monitoring these contaminants. In fact, many different types of antibiotics will be used simultaneously to prevent diseases in livestock and aquatic animals, causing antibiotic residues in food and the environment. Rapid and accurate simultaneous analysis of multiple antibiotics at low concentrations remains a major challenge in in the field of rapid detection. This study presents a sensitive and selective method for the simultaneous detection of two widely used antibiotics, enrofloxacin and chloramphenicol, by combining surface-enhanced Raman spectroscopy (SERS) with triangular silver nanoplates. Triangular silver nanoplates (TAgNPls) in the form of colloid were simply synthesized by chemical reduction method and then used as an effective SERS substrate, enhancing the Raman signals of the target antibiotics and enabling the detection of these antibiotics at trace levels. It was found that with a SERS substrate assembled from the above TAgNPls, the antibiotics enrofloxacin and chloramphenicol could be detected with detection limits of 2.6 µg/L and 4.3 µg/L, respectively. In addition, this SERS substrate also allows simultaneous detection of the above two antibiotics in one analytical sample with concentrations as low as 10 µg/L for both substances. The proposed method holds promise for addressing concerns related to antibiotic contamination in various environments and food sources, contributing to the advancement of analytical techniques for the trace detection of pharmaceutical residues.

Characteristics of the Klebsiella Pneumoniae Strain Isolated from a Positive Blood Culture of a Premature Newborn Baby According to the Results of Whole Genome Sequencing

Relevance. K. pneumoniae is a common nosocomial pathogen in pediatric hospitals, often characterized by the presence of a wide range of virulence factors and genetic determinants of antibiotic resistance. Аim. To analyze the results obtained during wholegenome sequencing of a Klebsiella pneumoniae strain isolated from a positive blood culture of a premature newborn. Materials and methods. An ESBL-producing strain of K. pneumoniae isolated from a positive blood culture of a newborn premature infant. Sequencing was performed on the MiSeq platform (Illumina). Analysis of DNA nucleotide sequences of the complete genome of K. pneumoniae was carried out using the website of the Center for Genomic Epidemiology. The search for genetic determinants of antibiotic resistance and virulence was carried out using online services. Results and its discussion. The resulting nucleotide sequence was 5,414,099 bp in length, and the proportion of GC nitrogenous bases was 57.3%. The isolated strain belonged to the sequence type ST3559, had 4 genes encoding the synthesis of enzymes that hydrolyze antibacterial drugs from the beta-lactam group, 2 genes providing resistance to quinolones/fluoroquinolones, 1 resistance gene each to trimethoprim, chloramphenicol, fosfomycin and aminoglycoside antibiotics. Most of the virulence factor genes identified in the studied strain ensure the recognition and absorption of iron ions necessary for the competitive functioning of the bacterial cell. K. pneumoniae possesses the acrA efflux pump gene and its regulators, as well as 4 prophage particles and 1 CRISPCas IE system. Conclusions. Whole-genome sequencing of the K. pneumoniae strain isolated from a positive blood culture of a premature newborn allows us to characterize in detail the causative agent of a generalized infection and detect a wide range of genetic determinants of virulence factors and antibiotic resistance. The ESBL-producing strain of K. pneumoniae, as the etiological agent of neonatal sepsis, was characterized by the presence of virulence genes, multidrug resistance, both due to genes encoding enzymes that hydrolyze antibiotics, and due to the presence of efflux pumps and their regulators. The use of the results of traditional cultural research methods together with high-throughput sequencing data is a promising area of scientific research and has a reserve of practical application in the field of clinical medicine, genetics of microorganisms, molecular epidemiology at the local and global levels

Degradation of thiamphenicol by La-Fe2O3/DBD/HCP synergistic catalytic system

In this study, a highly efficient La-Fe2O3/dielectric barrier discharge (DBD)/honeycomb ceramic plate synergistic catalytic system was successfully constructed by using modified iron oxide (Fe2O3) catalyst coating assisted DBD plasma, and the prepared catalytic coating was fully characterized by various techniques. The results indicate that the lanthanum (La) is efficiently and uniformly doped in Fe2O3, and the modified La-Fe2O3 catalyst exhibited a better photocatalytic performance. The overuse of Thiamphenicol (TAP), as a typical chloramphenicol antibiotic, has led to its accumulation in the aquatic environment. Accordingly, TAP was selected as the target contaminant to evaluate the catalytic activity of the synergistic system. The results confirmed that the catalytic ability of the synergistic catalytic system was significantly improved, and the data showed that the degradation rate of the synergistic system reached 99.1% under the same conditions compared with 68.2% for the single DBD plasma, which effectively improved low energy efficiency limitations of the single DBD technology. Through quantitative measurements of the concentrations of dissolved ozone (O3) and hydrogen peroxide (H2O2) in the system and radical trapping experiments, combined with emission spectroscopy, the mechanism of synergistic system degradation of TAP was analyzed. The intermediates in the degradation process were characterized by high-resolution mass spectrometry, and the degradation pathway of TAP was proposed based on the analysis of the intermediates and their combination with theoretical calculations. This study presents a theoretical basis for the improvement of DBD technology and a technical guide for the removal process of antibiotics from industrial wastewater.

Heterogeneous degradation of chloramphenicol antibiotic by peroxymonosulfate activated by FeS and FeS2: Mechanism and effects of catalysts dosage and pH

Antibiotics in the environmental waters pose long-term threat to ecological safety because of their persistent and potential toxic nature. FeS and FeS2 were proved to be efficient catalysts for the activation of peroxymonosulfate (PMS) and the generation of sulfate radical generation for refractory pollutant degradation. However, their performance for antibiotic degradation has not yet been comparatively and comprehensively investigated. Herein, the FeS/PMS and FeS2/PMS systems were developed to explore chloramphenicol (CAP) degradation under equal conditions. The results show that CAP was efficiently degraded in both two systems, with a removal efficiency exceeding 90 % within 120 min using 6 mM PMS and 0.6 g/L catalysts.Acceleration in degradation rate was observed in the FeS2/PMS system when the catalyst dosage ranged from 0.1 g/L to 1.0 g/L (constant PMS concentration) with a reaction rate constant (kobs) of 2.1-fold higher than that in the FeS/PMS system. However, the kobs were comparable with the PMS concentration range (constant catalyst dosage) in the two systems, suggesting that the catalysts were the rate-limiting step in CAP degradation process. The initial pH strongly affected CAP degradation in the FeS/PMS system but had little effect on that in the FeS2/PMS system. Surface Fe2+ played a dominant role in PMS activation, and S22−/S2− facilitated Fe2+ regeneration. Further, both FeS and FeS2 had stable activity for PMS activation during long-term use. This study proves the effectiveness of FeS and FeS2 for PMS activation for antibiotic degradation and differentiates their catalytic qualities, which will provide alternative heterogeneous catalysts for practical application.

Characterization of Diarrheagenic Escherichia coli and Salmonella enterica from Produce in the Chobe District of Botswana

Diarrheal disease is a leading cause of death in children in low- and moderate-income countries. Fresh produce, including fruits and vegetables, may harbor diarrheal disease-causing bacteria including strains of Salmonella enterica and Escherichia coli. This study aimed to determine the prevalence and antibiotic resistance profiles of S. enterica and E. coli isolated from produce samples (n = 207) obtained from retail markets in northern Botswana in Chobe District of Botswana in 2022. Samples were enriched in the appropriate selective media: Brilliant Green Bile Broth for E. coli and Rappaport Vassiliadis Broth for S. enterica. E. coli were confirmed by PCR detecting the phoA gene, and classified as potentially pathogenic through screening for the eae, stx, and stx2 and estIb genes. S. enterica isolates were confirmed using invA primers. Isolates were evaluated for resistance to ampicillin, amoxicillin-clavulanic acid, chloramphenicol, cefotaxime, doxycycline, streptomycin, sulfamethoxazole, and tetracycline antibiotic using the Kirby-Bauer Disk Diffusion method. E. coli was isolated from 15.5% of produce samples (n = 207). The gene eae was detected from 1.5% of samples, while stx1, stx2, and estIb were not detected. Resistance to one or more antibiotics was common (72%) with the majority of the resistant E. coli (n = 32) isolated from fruits (22%) and greens (18%) compared to other types of vegetables. Multidrug resistance (MDR, resistant to 3 or more antibiotics) was identified in 18% of samples. S. enterica was isolated from 3.4% of produce samples (7, n = 207). Resistance was uncommon among the S. enterica isolates (1/7). Overall prevalence of diarrheagenic S. enterica and E. coli was low; however, their presence and that of MDR E. coli in foods commonly consumed raw increases the risk to vulnerable populations. Strategies to reduce contamination of fresh produce and public education on washing and cooking some types of produce may be useful to reduce disease.

Tuning the shell thickness of N-doped interconnected hollow carbon sphere for the electrochemical sensing of antibiotic drug chloramphenicol.

N-doped hollow carbon spheres (NHCSs) with different shell thicknesses are constructed using various amounts of SiO2 precursor. An interconnected framework with diminished wall thickness ensures an efficient and continuous electron transport which helps to enhance theperformance of NHCS. Improvement of the electrocatalytic performance was shown in the determination of antibiotic drug chloramphenicol (CAP) due to theunique hollow thin shell morphology, ample defect sites, accessible surface area, higher surface-to-volume ratio and ansynergistic effect. Boosted electrocatalytic activity of 1.5 N-doped HCS (1.5 NHCS) was applied to detect CAP with a linear range and detection limit of 1-1150µM and 0.098µM (n = 3), respectively, with superior storage stability and considerable sensitivity. These results suggest that the proposed work can besuccessfully applied to the determination of CAP in milk and water samples.

Isolation and characterisation of Stenotrophomonas maltophilia, a multidrug resistant opportunistic pathogen from cultured Rainbow trout (Oncorhynchus mykiss, walbaum, 1792) in India

The farming of Rainbow trout, an exotic fish has advanced on a huge scale in north western regions of India which provides the best suitable climate and topography for its culture. The advancement in farming is challenged by the infectious diseases. The isolation of Stenotrophomonas maltophilia, an opportunistic pathogen has been reported from the cultured channel catfish in china, and cultured African catfish in West Bengal, India. The present study reports isolation of Stenotrophomonas maltophilia from the kidney of Rainbow trout, Oncorhynchus mykiss along with its biochemical, 16 s rRNA sequencing and phylogenetic analysis. Antibiotic susceptibility of isolates to 10 antimicrobial drugs was investigated using Disc diffusion method. The isolates were found to be resistant to multiple drugs, characterised by resistance to all Beta-lactams (Methicillin and Ampicillin), Macrolides (Erythromycin, Azithromycin and Rifampicin), aminoglycosides (Streptomycin, Amikicin) except Gentamicin and susceptible to Tetracycline and Chloramphenicol antibiotics. The auto-aggregation capability of the isolates showed 55.02 ± 5.9 and 49.52 ± 7.6% auto-aggregation after 24 h of incubation, respectively. The isolates showed 32.77 ± 6.78 and 29.41 ± 7.71 % hydrophobicity after 2 h of extraction with xylene, respectively. The 16 s rRNA sequences of the were submitted to the GenBank database with the accession numbers OP647420 and PP077305.

Evaluation of the probiotic, anti-microbial, anti-biofilm, and safety properties of Levilactobacillus brevis Lb13H

In this research, the probiotic potential, anti-microbial, anti-biofilm, and safety properties of Levilactobacillus brevis Lb13H were investigated. Also, Gaussian Process Regression (GPR) model was applied to predict some of experimental parameters. The strain demonstrated resistance to acidic pH, gastric and intestinal juices, and bile salts. Additionally, the strain exhibited 45.34% surface hydrophobicity, 36.55% auto-aggregation capacity, 26.30% co-aggregation, 10.20% adhesion to Caco-2 cells, 42.57% cholesterol removal, and 48.63% radical-scavenging properties. The probiotic strain was able to inhibit the adhesion of Listeria monocytogenes to intestinal cells by 31.30%, and its competitive inhibition percentage was 37.5%. Furthermore, the replacement of L. monocytogenes with the strain was measured at 22.10%. The most significant antimicrobial effect was observed against L. monocytogenes, while the least effect was noted against Rhizopus stolonifer. Haemolytic activity, DNase production, and biogenic amine production were not observed in the strain, which was also found to be sensitive to the antibiotics ciprofloxacin and chloramphenicol. The cell-free supernatant of L. brevis Lb13H effectively inhibited and degraded biofilm formation by L. monocytogenes, achieving effectiveness rates of 40.80% and 36.60% respectively. The results of modeling indicated that there is not any difference between actual and predicted data and GPR can predict the variables with high accuracy.

Screening and Selection of Antibiotics for Enhanced Production of Astaxanthin by Haematococcus lacustris.

Haematococcus lacustris (Girod-Chantrans) Rostafinski (Chlorophyta) is the richest microalgal source of astaxanthin. Natural astaxanthin from H. lacustris has been widely studied and used for commercial production worldwide. In this study, we examined the effects of 11 antibiotics (dihydrostreptomycin sulphate, neomycin, chloramphenicol, penicillin, streptomycin, ampicillin, kanamycin, gentamycin, hygromycin B, tetracycline, and paromomycin) on the biomass dry weight, growth, and astaxanthin yield of H. lacustris using Jaworski's medium without a nitrogen source. Astaxanthin content in H. lacustris was improved in the presence of ampicillin (0.25 g/L, 0.5 g/L, 1 g/L), chloramphenicol (0.25 g/L), and penicillin (0.25 g/L, 0.5 g/L, 1 g/L) in comparison to the control on day 15. The greatest increase in astaxanthin content on day 15 (6.69-fold) was obtained with the addition of penicillin (0.5 g/L) in comparison to the control. Similarly, on day 15, the cell numbers were also the highest for the H. lacustris culture grown with the addition of penicillin (0.5 g/L).

Enhancing antibacterial activity through green synthesis of silver nanoparticles with salvia officinalis extracts

This study aimed to test the effectiveness of water-based extracts and green-synthesized silver nanoparticle extracts from the Salvia officinalis plant in killing bacteria. We used the agar well diffusion method to see how well these extracts could fight against both Gram-positive bacteria (Staphylococcus epidermidis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). To understand the properties of the nanoparticles, we analyzed them using a UV-VIS spectrophotometer and a scanning electron microscope (SEM). The results showed that both types of extracts were effective against the bacteria, with performance similar to the antibiotic chloramphenicol used as a benchmark. An interesting finding was that combining the plant extracts with the antibiotic or the silver nanoparticle extract with the antibiotic significantly enhanced the ability to stop bacterial growth in all tested strains. The Gram-positive bacteria were more affected than the Gram-negative ones, suggesting a potential way to overcome bacterial resistance.

Testing the Effectiveness of Mangosized Skin Extract (Garcinia mangostana) as an Antimicrobial Against Bacteria Causing GI Tract Infections

The mangosteen fruit, which in Latin is called Garcinia mangostana Linn, is a plant whose entire parts can be used, including the skin of the fruit. Mangosteen fruit has bioactive compounds such as xanthones, especially α, β, and γ-mangostin where the level of antimicrobial action of α-mangosteen has been explored by many researchers and it has been observed that it is not only effective against bacteria but also against other microbes such as fungi and mycobacteria. Gastrointestinal system infections are a serious health problem and have not been completely resolved until now because cases are increasing every year. Gastrointestinal tract infections are a health problem in the world, including in Indonesia. Some infectious diseases of the gastrointestinal system that are often found in the wider community are typhoid fever, paratyphoid fever, diarrhea, and gastroenteritis. The bacteria that cause typhoid fever and paratyphoid fever are caused by the bacteria Salmonella Typhi & Salmonella Paratyphi. While diarrhea and gastroenteritis are caused by food poisoning and drinks contaminated by E. coli. This research is an experimental laboratory research using the disc diffusion/Kirby Bauer method by measuring the diameter of the clear zone which is a sign that there is an obstacle to the growth of Salmonella typhi and E. Coli bacteria by the antimicrobial compounds contained in the mangosteen fruit extract. The calculation results of this research showed that mangosteen peel extract (Garciana Mangostana L) against E. Coli bacteria with the antibiotic Chloramphenicol as control showed an average diameter of the inhibition zone of 30.5 mm, whereas Salmonella bacteria were not found or no inhibition zone was formed at the smallest concentration up to greatest concentration Keywords: Mangosteen Peel, garcinia mangostana l., Gastrointestinal Infections, Effectiveness of

Exploration of Alicyclobacillus spp. Genome in Search of Antibiotic Resistance.

The study investigates the antibiotic resistance (AR) profiles and genetic determinants in three strains of guaiacol-producing Alicyclobacillus spp. isolated from orchard soil and pears. Their phenotypic characteristics, such as spore formation; resistance to different factors, including drugs or disinfectants; or production of off-flavor compounds, can affect the taste and aroma of spoiled products. Food and beverages are potential vectors for the transfer of antibiotic resistance genes, which is a growing health concern; thus, microorganisms in food and beverages should not be a potential source of drug resistance to consumers. Whole-genome sequencing (WGS) was utilized to identify antibiotic resistance genes, metabolic pathways, and elements associated with guaiacol and halophenol production. Minimum inhibitory concentration (MIC) testing revealed that all strains were susceptible to eight out of nine tested antibiotics (ampicillin, gentamycin, kanamycin, streptomycin, clindamycin, tetracycline, chloramphenicol, and vancomycin) but exhibited high resistance to erythromycin. Analysis indicated that the erythromycin resistance gene, ribosomal RNA small subunit methyltransferase A (RsmA), was intrinsic and likely acquired through horizontal gene transfer (HGT). The comprehensive genomic analysis provides insights into the molecular mechanisms of antibiotic resistance in Alicyclobacillus spp., highlighting the potential risk of these bacteria as vectors for antibiotic resistance genes in the food chain. This study expands the understanding of the genetic makeup of these spoilage bacteria and their role in antimicrobial resistance dissemination.

Malaysian fermented shrimp paste (belacan): A source of potential probiotic lactic acid bacteria

In the present work, lactic acid bacteria (LAB) isolated from Malaysian fermented shrimp paste, locally known as belacan, were screened for their probiotic potential. Seventeen isolates were characterised after a preliminary subtractive screening based on morphology (catalase-negative and Gram-positive cocci/bacilli). The isolates were evaluated based on their tolerance towards the gastrointestinal environment, haemolytic properties, antagonism effect against selected pathogens, and antibiotic resistance patterns. The isolates were also molecularly identified via 16S rRNA sequencing. Out of 17, three isolates (BE3, BE7, and BE16) demonstrated tolerance to pH 2.5 (survival rates above 90%) and 0.3% bile salts (survival rates above 50%). Further screening performed on the three isolates indicated that all strains did not show undesirable haemolytic activities, and could inhibit the growth of Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Salmonella Typhimurium to varying degrees. Additionally, the isolates were susceptible to ampicillin and chloramphenicol antibiotics, and resistant to nalidixic acid, streptomycin, and vancomycin antibiotics. The 16S rRNA gene sequence analysis identified the isolates as Lactobacillus plantarum with 98, 100, and 99% similarity for BE3, BE7, and BE16, respectively. Therefore, these findings suggested that LAB isolated from Malaysian fermented shrimp paste exhibited promising probiotic properties.

Self-Assembly of the Porphyrin Monomer on the Surface of Fe/Graphene Material: A Novel Sensing Material for the Detection of Chloramphenicol Antibiotic in Aqueous solution.

Currently, electrochemical sensors are being developed and widely used in various fields, and new materials are being explored to enhance the precision and selectivity of the sensors. The present investigation involved the fabrication of a Fe/graphene/porphyrin nanocomposite through self-assembly, wherein the individual porphyrin molecules were arranged on the Fe/graphene nanomaterials' surface. The Fe/graphene nanoparticles were synthesized utilizing a green approach, wherein leaf extract was employed as the reducing agent. The resulting materials underwent comprehensive characterization using a range of contemporary techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. The study's findings revealed that the nanocomposites of Fe/graphene/porphyrin comprised zero-valent iron nanoparticles, exhibiting an average particle size ranging from 15 to 60 nm. These nanoparticles were seen to be evenly dispersed across the graphene sheets. The presence of nanostructure porphyrin nanofibers, measuring 20 nm in diameter, was also shown to exhibit strong integration with the surface of the Fe/graphene nanomaterials. The electrochemical properties of the Fe/graphene/porphyrin nanocomposite were also investigated, demonstrating that the prepared material could be effectively employed as a sensing electrode in the electrochemical sensor for detecting Chloramphenicol (CAP) through CV, EIS, and DPV techniques using a three-electrode electrochemical system. Under optimal conditions, Fe/graphene/porphyrin exhibited a high current response when detecting CAPs. Electrochemical sensors created using Fe/graphene/porphyrin nanocomposite have high stability and repeatability, and they hold promise in developing sensors capable of identifying other antibiotic residues in agriculture.

Synergistic nanomaterial system for luminescence sensing of MnO4- anion and enhanced photocatalytic removal of antibiotic chloramphenicol (CAP) in aqueous environments using Dy3+/Tb3+ co-doped NaYF4 and graphene oxide hybrid

The presence of industrial pollutants in water bodies, particularly metal anions and organic pollutants, has put human health and the environment at risk worldwide, triggering the research and development of multifunctional nanoparticles that not only have excellent luminescence detection ability but also possess simultaneous photo-degradation activity against harmful pollutants. Herein, we have synthesized Dy3+/Tb3+ co-doped NaYF4 (Tb-NP) and (Tb-GO) NaYF4:Dy3+/Tb3+@GO(GO=Graphene oxide) nano hybrids via hydrothermal approach and tested their functional activity for the fluorescence selective detection of MnO4- anions and photocatalytic degradation of drug Chloramphenicol (CAP) in aqueous medium. The physicochemical characterization of prepared nanosamples was examined utilizing variety of analytical methods. The luminescent property of NaYF4:Dy3+/Tb3+(7 %) revealed that it is exceptionally sensitive and selective towards the detection ofMnO4- anion in aqueous medium. It was observed that, when varied amount of MnO4- anion was added to a suspension solution containing the synthesized NaYF4:Dy3+/Tb3+(7 %) chemosensor, the photoluminescence emission band at 545 nm was significantly quenched. Moreover, NaYF4:Dy3+/Tb3+(Tb-NP) exhibited the limit of detection (LOD)value of 0.65 ppm along with high Stern-Volmer (Ksv) quenching constant value of 4.75 ×105 M−1 for MnO4- anion, indicating great selectivity and sensitivity of the designed nanosensors towards MnO4- anion. Further, the Graphene oxide (GO) conjoined NaYF4:Dy3+/Tb3+(7 %) nanohybrid showed accelerating photocatalytic activity toward the degradation of CAP in aqueous medium under UV-irradiation. The obtained results of UV-Vis spectroscopy clearly indicate that NaYF4:Dy3+/Tb3+@GO (Tb/GO) nanohybrid can act as a superior nanocatalyst than that of NaYF4:Dy3+/Tb3+(Tb-NP) nanophosphors. The photocatalytic efficiency of NaYF4:Dy3+/Tb3+@GO (Tb/GO) nanohybrid toward degradation of CAP is around 95.6 % within 50 minutes under UV light and it maintains remarkable stability even after five repeated catalytic cycles. In conclusion, this study presents a feasible method for immediate detection of MnO4- anion and improved photo-catalytic degradation of CAP in an aqueous medium employing NaYF4:Dy3+/Tb3+(Tb-NP) and NaYF4:Dy3+/Tb3+@GO (Tb/GO) as dual functional nanomaterials.

Assessment of the probiotic, anti-bacterial, and anti-biofilm characteristics of Lacticaseibacillus rhamnosus CWKu-12, along with its potential impact on the expression of virulence genes in Listeria monocytogenes ATCC 19115

The purpose of this study was to investigate the potential probiotic properties, gene expression related to biofilm formation, and anti-biofilm capabilities of Lacticaseibacillus rhamnosus CWKu-12. This strain showed notable resistance to acidic conditions, gastrointestinal environments, and bile salts. Additionally, L. rhamnosus displayed significant levels of auto-aggregation (36.60%), hydrophobicity (52.60%), co-aggregation (29.10%), free radical scavenging activities (55–59%), and cholesterol reduction (49.30%). Its ability to compete with, replace, and hinder the adhesion of Listeria monocytogenes was measured at 41.70%, 22.60%, and 30.54% respectively. L. rhamnosus also showed an adhesion rate of 11.80% to epithelial cells, did not exhibit DNase or hemolytic activity. It was susceptible to the antibiotics ciprofloxacin, erythromycin, and chloramphenicol and semi-susceptible to ampicillin, imipenem, nitrofurantoin, and nalidixic acid. The strain's cell free supernatant (CFS) effectively inhibited and eliminated L. monocytogenes biofilm formation, with inhibitory rates of 44.30% and eradication rate of 38.70%. Treatment with CFS also led to a significant decrease in the expression of various genes related to L. monocytogenes by percentages ranging from 35.54% to 79.80%. Overall, these findings support the potential of L. rhamnosus CWKu-12 as a probiotic, with its ability to survive in the digestive system, and combat harmful bacteria making it a promising candidate.

Isolation and Identification of Bacteria from Electronic devices used by Students and Staffs in Ines Ruhengeri

Background: Electronic devices have become one of the most essential accessories being used in daily lives including schools. Those devices increase the communication and using them makes learning much easier. Microbial contamination of electronic devices and inanimate surface of electronic equipment at INES-Ruhengeri can have a significant role for transmission of pathogenic bacteria. Aim: The aim of this study was to isolate and identify bacteria from electronic devices used by students and staffs at INES-Ruhengeri University. Methodology: This cross-sectional study was done on 40 electronic devices such as computers, microscopes, global positioning system (GPS) and total stations A random sampling method was applied from sterile swab soaked in peptone water solution by the technique of bearing on the surface of the entire devices and then placed in a transport medium. Collected samples were then taken in INES-Ruhengeri Microbiology laboratory for further experiments. Results: All 40 electronic devices were contaminated with bacteria. The most predominant bacteria isolated from electronic devices was S.aureus (25.9%) followed by Bacillus spp(24.1%), K.pneumonia(12.9%), S.epidermis(12.9%), Micrococcus spp(7.4%), P.aeruginosa(5.5%), E.coli(3.3%), Salmonella spp(3.3%) and Shigella spp(3.3%). Antimicrobial susceptibility pattern of selected antibiotics was performed. Norfloxin was the most sensitive antibiotic on all isolated bacteria. Chloramphenicol antibiotic shown no activity over any of the isolated bacteria, to imply that all bacteria had resistance on it. Conclusion: This study shown that there is bacterial contamination to all devices and antibiotic susceptibility test shown that some antibiotics were sensitive and resistant to the isolated bacteria.

Construction of novel Ce2(WO4)3/rGO nanocomposites for efficient photocatalytic mitigation of antibiotic drug chloramphenicol

In this study, we present the synthesis and characterization of a novel cerium tungstate decorated reduced graphene oxide (Ce2(WO4)3@rGO or CeW@rGO) nanocomposite via a facile hydrothermal method. Comprehensive analyses including XRD, FTIR, SEM, TEM, and XPS were conducted to elucidate the crystal structure, chemical states, morphology, and optical properties of the synthesized nanocomposite. The CeW@rGO exhibited a reduced band gap of 2.14 eV compared to 2.33 eV for CeW, enhancing visible light absorption. Photocatalytic experiments demonstrated the superior efficiency of CeW@rGO, achieving 98.03 % degradation of the antibiotic chloramphenicol (CIP) within 45 min under visible light irradiation. The enhanced photocatalytic performance is attributed to the improved charge separation and extended lifetime of photo-induced charge carriers, facilitated by the rGO. Reactive oxidative species such as O2•− and •OH were identified as key contributors to the degradation process, as confirmed by radical scavenging studies. The plausible degradation mechanism of CIP was proposed based on LC-MS analysis. This work highlights the potential of CeW@rGO as an efficient and sustainable photocatalyst for environmental remediation, offering significant advancements in the field of photocatalytic degradation of organic contaminants. The improved efficiency of the photocatalyst was primarily due to the enlarged surface area and the addition of CeW and rGO to the composite sample. These additions enhance the catalyst's ability to adsorb pollutants and increase the separation of electrons and holes at the interface between two semiconductors by creating an internal electric field. The results toprovide the successfully creation ofCeW/rGO nanocomposites that are cost-effective, highly efficient, lightweight, and sustainable for use in environmental applications.