Concentrations Of Erythromycin Research Articles

Screening for Antibiotic Resistance Genes in Bacteria and the Presence of Heavy Metals in the Upstream and Downstream Areas of the Wadi Hanifah Valley in Riyadh, Saudi Arabia.

Valley surface water is considered a focal public health concern owing to the presence of multi-drug-resistant bacteria. The distribution of antimicrobial resistance (AMR) bacteria in the surface water is affected by the presence of multiple factors, including antibiotics coming from wastewater discharge or other contaminant sources such as pharmaceuticals, biocides, and heavy metals. Furthermore, there is evidence suggesting that high levels of antibiotic resistance genes (ARGs) can be transferred within bacterial communities under the influence of heavy metal stress. Hence, the primary aim of this study is to investigate the presence of heavy metals and bacterial ARGs in upstream as well as downstream locations of Wadi Hanifah Valley in Riyadh, Saudi Arabia. Sample collection was conducted at eighteen surface water sites within the valley in total. The selection of ARGs was associated with the most common antibiotics, including β-lactam, tetracycline, erythromycin, gentamicin, sulphonamide, chloramphenicol, vancomycin, trimethoprim, and colistin antibiotics, which were detected qualitatively using polymerase chain reaction (PCR) technology. The tested antibiotic resistance genes (ARGs) included (blaNDM-1 (for the antibiotic class Beta-lactamases), mecA (methicillin-resistant Staphylococcus aureus), tet(M) and tet(B) (for the antibiotic class Tetracycline), ampC (for the antibiotic class Beta-lactamases), vanA (for the antibiotic class vancomycin), mcr-1 (for the antibiotic class colistin), erm(B) (for the antibiotic class erythromycin), aac6'-Ie-aph2-Ia (for the antibiotic class Gentamicin), sulII (for the antibiotic class sulphonamide), catII (for the antibiotic class Chlorophincol), and dfrA1 (for the antibiotic class trimethoprim). Moreover, an assessment of the levels of heavy metals such as lithium (Li), beryllium (Be), chromium (Cr), cobalt (Co), arsenic (As), cadmium (Cd), tin (Sn), mercury (Hg), and lead (Pb) was conducted by using inductively coupled plasma mass spectrometry (ICPMS). According to our findings, the concentrations of sulphonamide, erythromycin, and chloramphenicol ARGs (erm(B), sulII, and catII) were observed to be the most elevated. Conversely, two ARGs, namely mecA and mcr-1, were not detected in the samples. Moreover, our data illustrated a significant rise in ARGs in the bacteria of water samples from the upstream sites as compared with the water samples from the downstream sites of Wadi Hanifah Valley. The mean concentration of Li, Be, Cr, Co, As, Cd, Sn, Hg, and Pb in the water samples was estimated to be 37.25 µg/L, 0.02 µg/L, 0.56 µg/L,0.32 µg/L, 0.93 µg/L, 0.01 µg/L, 200.4 µg/L, 0.027 µg/L, and 0.26 µg/L, respectively, for the selected 18 sites. Furthermore, it was revealed that the concentrations of the screened heavy metals in the water samples collected from various sites did not surpass the maximum limits set by the World Health Organization (WHO). In conclusion, this study offers a concise overview of the presence of heavy metals and ARGs in water samples obtained from the Wadi Hanifah Valley in Riyadh, KSA. Such findings will contribute to the ongoing monitoring and future risk assessment of ARGs spread in surface water.

Chronic toxic effects of erythromycin and its photodegradation products on microalgae Chlorella pyrenoidosa

The photodegradation products (PDPs) of antibiotics in the aquatic environment received increasing concern, but their chronic effects on microalgae remain unclear. This study initially focused on examining the acute effects of erythromycin (ERY), then explored the chronic impacts of ERY PDPs on Chlorella pyrenoidosa. ERY of 4.0 − 32 mg/L ERY notably inhibited the cell growth and chlorophyll synthesis. The determined 96 h median effective concentration of ERY to C. pyrenoidosa was 11.78 mg/L. Higher concentrations of ERY induced more serious oxidative damage, antioxidant enzymes alleviated the oxidative stress. 6 PDPs (PDP749, PDP747, PDP719, PDP715, PDP701 and PDP557) were identified in the photodegradation process of ERY. The predicted combined toxicity of PDPs increased in the first 3 h, then decreased. Chronic exposure showed a gradual decreasing inhibition on microalgae growth and chlorophyll content. The acute effect of ERY PDPs manifested as growth stimulation, but the chronic effect manifested as growth inhibition. The malonaldehyde contents decreased with the degradation time of ERY at 7, 14 and 21 d. However, the malonaldehyde contents of ERY PDPs treatments were elevated compared to those in the control group after 21 d. Risk assessment still need to consider the potential toxicity of degradation products under long-term exposure.

Mobile phone-assisted imprinted nanozyme for bicolor colorimetric visual detection of erythromycin in river water and milk samples

The residues of erythromycin (ERY) may have negative impacts on the ecological environment, health, and food safety. How to detect ERY effectively and visually is a challenging issue. Herein, we synthesized a molecularly imprinted polymer based nanozymes for selective detection of erythromycin (ERY-MIPNs) at neutral pH, and developed a mobile phone-assisted bicolor colorimetric detection system. This system produced a wide range of color changes from blue to pinkish purple as the ERY concentration increased, making it easy to capture the visualization result. Also, the system showed good sensitivity to ERY ranging from 15 to 135 μM, with a detection limit of 1.78 μM. In addition, the system worked well in the detection of ERY in river water and milk, with the recoveries of 95.57% ∼ 103.20%. These data suggests that this strategy is of considerable potential for practical applications and it provides a new idea for visual detection with portable measurement.

Anthracene degradation involved by antibiotic biosynthesis monooxygenase (ABM) in Comamonas testosteroni

It is well known that anthracene can cause serious health problems, which is why anthracene biodegradation as a method to reduce health risks has drawn the interest of researchers. However, antibiotic contamination in the environment can seriously affect the biodegradation of anthracene. In the present study, Comamonas testosteroni (CT1) had the highest degradation efficiency of anthracene (88.1%), and was still 46.6% when erythromycin concentration was 1/4MIC (8 μg mL−1). Also, compared to CK, the prokaryotic transcriptome analysis of CT1 in anthracene degradation revealed an up-regulated gene that encodes antibiotic biosynthesis monooxygenase (ABM) in both anthracene and anthracene-erythromycin groups. In addition, compared to strain CT1, the CtABM knockout mutant (CT-M) showed a significant decrease in anthracene degradation efficiency. In contrast, Escherichia coli (E.coli) DH5α transformed with CtABM (EM1) exhibited a faster degradation efficiency than DH5α. Furthermore, the antimicrobial susceptibility test showed that compared to DH5α, EM1 had significant resistance to erythromycin. And the purified recombinant CtABM (rABM) had a specific activity of 2.53 μmol min−1·mg−1 protein based on the oxidation of anthracene at pH 7.5 and 35 °C. Additionally, compositional analysis identified 4-benzyloxy-3-methoxybenzyl alcohol and 4-methylphthalaldehyde as anthracene metabolites by EM1, suggesting a novel anthracene degradation pathway.

Unveiling the impact of antimicrobial-infused water on hydroponic baby leafy vegetables (lettuce, rocket, and watercress): Physiological effects and food safety

The uptake of antimicrobials by vegetables can reduce plant production and compromise food safety, as these compounds can disrupt plant physiology and accumulate in plant tissues. In this study, we investigated the effects of environmentally representative concentrations of ciprofloxacin (CIP, 1.5 µg L−1), erythromycin (ERY, 1.5 µg L−1), and/or sulfamethoxazole (SULFA, 0.3 µg L−1) on the physiology (growth and oxidative stress markers), nutraceutical characteristics (mineral composition and total phenolic content), and antimicrobial accumulation in hydroponically grown baby leaf lettuce, rocket, and watercress plants. Only watercress exhibited disrupted shoot growth. Furthermore, increased concentrations of total phenolic compounds were observed in rocket plants when exposed to the antimicrobials. The drugs also significantly impacted on mineral nutrition, altering the mineral-recommended daily intake (RDI) of all plants, with rockets and watercress being the most affected. Additionally, higher human health risks were observed in plants exposed to CIP, particularly concerning children. The presence of CIP in the growing water of hydroponic vegetables poses a notable risk to food safety due to the plant's ability to accumulate the drug in its edible parts. Moreover, beyond the adverse effects on human health, using antimicrobial-contaminated water in vegetable cultivation can also disrupt watercress production, leading to significant economic losses.

Prevalence, antibiotic resistance, and genomic characterisation of Campylobacter spp. in retail chicken in Hanoi, Vietnam.

Campylobacter spp. are a leading cause of bacterial foodborne zoonosis worldwide, with poultry meat and products recognised as a significant source of human infection. In Vietnam there are few data regarding the occurrence, antimicrobial resistance, and genomic diversity of Campylobacter in poultry and poultry meat. The aim of this study was to estimate the prevalence of Campylobacter in chicken meat at retail in Hanoi, determine antimicrobial sensitivities of the Campylobacter isolated, and assess their genetic diversity. A total of 120 chicken meat samples were collected from eight traditional retail markets (n=80) and four supermarkets (n=40). Campylobacter was isolated following ISO 10272-1 : 2017 and identification verified by PCR. The prevalence of Campylobacter was 38.3 % (46/120) and C. coli was the most prevalent species in both retail markets (74 %) and supermarkets (88 %). The minimum inhibitory concentrations for ciprofloxacin, erythromycin, gentamicin, nalidixic acid, streptomycin, and tetracycline were determined by broth microdilution for 32 isolates. All characterised Campylobacter were resistant to ciprofloxacin, nalidixic acid, and tetracycline, with corresponding resistance determinants detected in the sequenced genomes. Most C. coli were multidrug resistant (24/28) and two harboured the erythromycin resistance gene ermB on a multiple drug-resistance genomic island, a potential mechanism for dissemination of resistance. The 32 isolates belonged to clonal complexes associated with both poultry and people, such as CC828 for C. coli. These results contribute to the One Health approach for addressing Campylobacter in Vietnam by providing detailed new insights into a main source of human infection and can inform the design of future surveillance approaches.

Efficacy of delafloxacin alone and in combination with cefotaxime against cefotaxime non-susceptible invasive isolates of Streptococcus pneumoniae.

We assessed the in vitro activity of delafloxacin and the synergy between cefotaxime and delafloxacin among cefotaxime non-susceptible invasive isolates of Streptococcus pneumoniae (CNSSP). A total of 30 CNSSP (cefotaxime MIC > 0.5 mg/L) were studied. Serotyping was performed by the Pneumotest-Latex and Quellung reaction. Minimum inhibitory concentrations (MICs) of delafloxacin, levofloxacin, penicillin, cefotaxime, erythromycin and vancomycin were determined by gradient diffusion strips (GDS). Synergistic activity of delafloxacin plus cefotaxime against clinical S. pneumoniae isolates was evaluated by the GDS cross method. Delafloxacin showed a higher pneumococcal activity than its comparator levofloxacin (MIC50, 0.004 versus 0.75 mg/L and MIC90, 0.047 versus >32 mg/L). Resistance to delafloxacin was identified in 7/30 (23.3%) isolates, belonging to serotypes 14 and 9V. Synergy between delafloxacin and cefotaxime was detected in 2 strains (serotypes 19A and 9V). Antagonism was not observed. Addition of delafloxacin increased the activity of cefotaxime in all isolates. Delafloxacin susceptibility was restored in 5/7 (71.4%) strains. CNSSP showed a susceptibility to delafloxacin of 76.7%. Synergistic interactions between delafloxacin and cefotaxime were observed in vitro among CNSSP by GDS cross method.

Brevicidine acts as an effective sensitizer of outer membrane-impermeable conventional antibiotics for Acinetobacter baumannii treatment.

The antibiotic resistance of Acinetobacter baumannii poses a significant threat to global public health, especially those strains that are resistant to carbapenems. Therefore, novel strategies are desperately needed for the treatment of infections caused by antibiotic-resistant A. baumannii. In this study, we report that brevicidine, a bacterial non-ribosomally produced cyclic lipopeptide, shows synergistic effects with multiple outer membrane-impermeable conventional antibiotics against A. baumannii. In particular, brevicidine, at a concentration of 1 μM, lowered the minimum inhibitory concentration of erythromycin, azithromycin, and rifampicin against A. baumannii strains by 32-128-fold. Furthermore, mechanistic studies were performed by employing erythromycin as an example of an outer membrane-impermeable conventional antibiotic, which showed the best synergistic effects with brevicidine against the tested A. baumannii strains in the present study. The results demonstrate that brevicidine disrupted the outer membrane of A. baumannii at a concentration range of 0.125-4 μM in a dose-dependent manner. This capacity of brevicidine could help the tested outer membrane-impermeable antibiotics enter A. baumannii cells and thereafter exert their antimicrobial activity. In addition, the results show that brevicidine-erythromycin combination exerted strong A. baumannii killing capacity by the enhanced inhibition of adenosine triphosphate biosynthesis and accumulation of reactive oxygen species, which are the main mechanisms causing the death of bacteria. Interestingly, brevicidine and erythromycin combination showed good therapeutic effects on A. baumannii-induced mouse peritonitis-sepsis models. These findings demonstrate that brevicidine is a promising sensitizer candidate of outer membrane-impermeable conventional antibiotics for treating A. baumannii infections in the post-antibiotic age.

Integrating transcriptomics and biochemical analysis to understand the interactive mechanisms of the coexisting exposure of nanoplastics and erythromycin on Chlorella pyrenoidosa

Nanoplastics and antibiotics frequently co-exist in water polluted by algal blooms, but little information is available about interaction between substances. Erythromycin, as a representative of antibiotics, has been frequently detected in aquatic environments. This investigation attempted to reveal the interaction mechanism of nanoplastics and erythromycin on Chlorella pyrenoidosa. Results demonstrated that the joint toxicity of erythromycin and nanoplastics was dynamic and depended on nanoplastics concentration. Antagonistic effects of 1/2 or 1 EC50 erythromycin and nanoplastic concentration (10 mg/L) on the growth of C. pyrenoidosa was observed. The joint toxicity of 1/2 or 1 EC50 erythromycin and nanoplastic concentration (50 mg/L) was initially synergistic during 24–48 h and then turned to antagonistic during 72–96 h. Consequently, antagonistic effect was the endpoint for joint toxicity. Integration of transcriptomics and physiological biochemical analysis indicated that the co-existence of nanoplastics and erythromycin affected the signal transduction and molecular transport of algal cell membrane, induced intracellular oxidative stress, and hindered photosynthetic efficiency. Overall, this study provided a theoretical basis for evaluating the interactive mechanisms of nanoplastics and antibiotics.

The Use of Biochar for the Removal of Erythromycin Residues from Aqueous Environment

The presence of residual antibiotics in soil and water ecosystems has harmful effects on the environment, ecological food chain, and human health. It is also a driving factor for bacterial antibiotic resistance. Erythromycin is an antibiotic found in the water bodies in several countries due to improper disposal or inefficient wastewater treatment. Biochar is an adsorbent material prepared by the pyrolysis of discarded waste items including food and garden waste that could provide a cost-effective and efficient method for eliminating antibiotics from wastewater. This study evaluated whether biochar is successful in removing the antibiotic erythromycin from an aqueous environment through adsorption. It also investigated whether various factors such the pH of the aqueous environment or the concentration of erythromycin impacted its adsorption. Lastly, it was compared to commercially available activated charcoal to determine which material adsorbs erythromycin more effectively. The biochar is obtained from the pyrolysis of solid domestic waste including food, paper, and garden waste at 300°C. All experiments were conducted over three hours at neutral pH and the adsorption onto 1.0 g (±1 mg) of biochar was calculated in mg/g. The solutions were continuously stirred at 200 rpm and the temperature was set to 23°C. Samples were analysed using reverse-phase high-performance liquid chromatography (HPLC) at 210 nm using a mixture of methanol-water at alkaline pH (80:20, v/v) as a mobile phase. It was found that the highest concentration of erythromycin, 100 mg/L showed a better adsorption capacity (3.71 mg/g) compared to samples at a concentration of 50 mg/L (1.90 mg/g) and 25 mg/L (0.95 mg/g). In addition, samples obtained from the neutral (pH 7) solution showed slightly greater drug adsorption in comparison to samples obtained from the acidic (pH 5) and alkaline (pH 9) solutions. Lastly, biochar was more effective than activated charcoal in adsorbing erythromycin where a 1.0 g of biochar adsorbed almost twice the amount of the drug. Overall, this study suggested the use of a biochar prepared from discarded materials as a simple cost-effective additional method for removing erythromycin from water which could be further optimised or combined with another method achieve a full elimination.

Volatile fatty acids recovery and antibiotic degradation from erythromycin fermentation residues by combined thermal pretreatment and anaerobic fermentation: Insights into microbial communities and metabolic pathways

High resistance of erythromycin has been the key factor restricting the disposal of erythromycin fermentation residues (EFR). Considering the high sensitivity of erythromycin to acidic conditions, anaerobic fermentation may be a good approach for EFR treatment, through which pH decreases along with the volatile fatty acids (VFA) accumulation. This study firstly explored the EFR treatment by combined thermal pretreatment and anaerobic fermentation. Results showed that thermal pretreatment and anaerobic fermentation exhibited a synergistic effect on erythromycin removal. Erythromycin concentration decreased to 20.0 mg/L with the maximum removal rate of 60.0%, which was 140% and 71.4% higher than erythromycin removal by sole thermal pretreatment and anaerobic fermentation. Thermal pretreatment induced the increased VFA production by 22.3% with the highest VFA concentration of 5325.4 mg/L. Microbial analysis shows that thermal pretreatment stimulated erythromycin degradation and VFA production by increasing the microbial diversity and enriching the functional enzymes involved in acetate-producing pathways.

A novel AIE material for sensing of Erythromycin in pure water by hydrogen bond in portable test strips and cellular imaging applications

Erythromycin could be used to treat various bacterial infection, but it was harmful to the colonic microflora. Therefore, it is highly desirable to develop a fluorescence probe that could selectively and sensitively detect Erythromycin in pure water. In this work, a fluorescent probe named EHMC, which exhibited aggregation-induced emission (AIE) characteristic in solid state and water/EtOH binary solvent was developed for “turn on” sensing Erythromycin in pure water with high selectivity and sensitivity (detection limit: 1.78 × 10−8 M). Also, there are fewer interference from other antibiotics in the detection process of probe EHMC for Erythromycin. Moreover, probe EHMC could as a portable test strips for highly selective detection of Erythromycin and identification of different concentrations of Erythromycin. In addition, living cells imaging experiments displayed that probe EHMC could detect Erythromycin in A549 cells and BEAS-2B cells successfully. Combined with the theoretical calculation results The sensing mechanisms that the CO in Erythromycin and OH in EHMC formed intermolecular hydrogen bond and further formed new aggregates were confirmed by job’ plot, 1H NMR, FT-IR, ESI-MS, DLS and TEM and DFT calculation.

Erythromycin fermentation residue exposure induces a short-term wave of antibiotic resistance in a soil-lettuce system

The pattern of antibiotic resistance assembly and their unclear transfer in a soil-lettuce system render the treated erythromycin fermentation residue (EFR) land application risky. Herein, the antibiotic resistance genes (ARGs), mobile gene elements, and microbial communities were examined under erythromycin stress at three stages of lettuce growth. Erythromycin exhibited degradation rates of 99.4 % in soils for 60 d, with little uptake in the seedling tissues, reaching a 0.11–0.71 bioconcentration factor range. The EFR application rate must be limited <1 % to avoid human exposure risk. The diversity, biotic networks complexity, and edaphic ARG abundances of the rhizospheric microbial communities increased at the early stage, but returned to the control levels at the mature stage. The Planomicrobium and Pseudomonas bacterial genera were important biotic factors for erythromycin variation. Thirty-three MLSB genes (macrolide, lincosamide, and streptogramin B) conferring resistance to erythromycin were detected in soil, but only two endophytic ARGs (mphA-01 and ermX) were identified, with members of the Microvirga genus being the potential hosts. Partial least-squares path modeling suggested that erythromycin concentration was the main factor for endophytic ARGs evolution. This study highlighted the leaf endophytic ARG emergence and potential exposure human risks majorly caused by the drug traces in antibiotic fermentation residues.

Impacts of Organic Emerging Contaminants (Erythromycin, Ibuprofen, and Diclofenac) on the Performance of a Membrane Bioreactor Treating Urban Wastewater: A Heterotrophic Kinetic Investigation.

The occurrence of emerging organic contaminants, such as pharmaceuticals, is a growing global concern. In this research, for a membrane bioreactor (MBR) laboratory plant operating at a hydraulic retention time (HRT) of 24 h, fed with real urban wastewater, the heterotrophic biomass behaviour was analysed for two concentrations of erythromycin, ibuprofen, and diclofenac. The concentrations studied for the first phase were erythromycin 0.576 mg L-1, ibuprofen 0.056 mg L-1, and diclofenac 0.948 mg L-1. For Phase 2, the concentrations were increased to erythromycin 1.440 mg L-1, ibuprofen 0.140 mg L-1, and diclofenac 2.370 mg L-1. Heterotrophic biomass was affected and inhibited by the presence of pharmaceutical compounds in both phases. The system response to low concentrations of pharmaceutical compounds occurred in the initial phase of plant doping. Under these operating conditions, there was a gradual decrease in the concentration of mixed liquor suspended solids and the removal of chemical oxygen demand of the system, as it was not able to absorb the effect produced by the pharmaceutical compounds added in both phases.

SYNERGISTIC EFFECTS OF RUTA GRAVEOLENS L. EXTRACTS WITH ERYTHROMYCIN AGAINST SKIN ISOLATES OF MLS-RESISTANT STAPHYLOCOCCI

The aim: to research the synergistic interaction of garden ruta ethanolic extracts with erythromycin against skin isolates of MLS-resistant staphylococci.&#x0D; Materials and methods. The study of the synergistic interaction of 5 water-ethanol extracts of the garden ruta herb (extractants - 40%, 50%, 70%, 90% and 96% ethanol) with erythromycin was performed on 11 clinical strains of skin isolates of MLS-resistant staphylococci. Determination of MLS-resistance was carried out by the disc-diffusion method. MIC of erythromycin of staphylococcal strains was determined by the method of two-fold serial dilutions in Muller-Hinton broth. A screening analysis of the potential ability for synergistic interaction of ruta herb extracts with erythromycin was carried out by the method of microdiffusion in agar. The validity of the synergistic interaction of the studied ruta herb extracts with erythromycin was confirmed by the сheckerboard assay with the calculation of the Fractional Inhibition Concentration Index (FICI).&#x0D; Results. Using the qualitative method of microdiffusion in agar, it was established that subbacteriostatic concentrations of erythromycin increased the diameters of the zones of inhibition of the bacterial growth around the wells with all the studied extracts in 50±1.3% of the test strains. The best results were shown by the 96% extract of ruta herb, which increased the diameters of zones by 49.7-75.5%. Around the wells with 70% and 90% extracts, the diameters of zones increased by 32.4-48.3% and 34.6-52.4%, respectively. A decrease in MIC of erythromycin in the presence of efflux pump blockers - reserpine and potassium arsenate was observed in 2-4 times at four strains with R-phenotype, twice - at one strain with Neg-phenotype and one strain with D-phenotype of MLS-resistance. 90% and 96% ruta herb extracts showed a synergistic interaction with erythromycin among the largest number of researched strains, regardless phenotype of MLS-resistance (4-128-fold decrease in MIC of ERY). The least antibiotic potentiating ability was shown by 40% and 50% ruta herb extracts, under the influence of which the MIC of erythromycin decreased by 2-32 and 2-64 times, respectively.&#x0D; Ruta herb extracts in 90% and 96% ethanol showed a synergistic interaction with erythromycin (average FICI values 0.49±0.42 and 0.42±0.25, respectively). Extracts in 40%, 50% and 70% ethanol were generally characterized by an additive effect (FICI values of 0.72±0.47, 0.63±0.24 and 0.68±0.38, respectively).&#x0D; It should be noticed, that the synergistic interaction of erythromycin and subbacteriostatic concentrations (1/4, 1/8, 1/16 IPC) of ethanolic ruta herb extracts against the studied skin isolates of MLS-resistant staphylococci had a dose-dependent nature (F=6,9812; F&gt;Fcrit.= 2,8916; p=0,000917).&#x0D; Conclusions. Therefore, water-ethanol extracts of garden ruta herb demonstrate the ability to 4-128-fold reduction of MIC of erythromycin in MLS-resistant strains of S. epidermidis and S. aureus; extracts on 90% and 96% ethanol have more pronounced erythromycin-potentiating properties compared to extracts made on 40%, 50% and 70% ethanol. The synergistic interaction of erythromycin with ruta herb extracts was manifested on staphylococcal strains with efflux and combined mechanisms of MLS-resistance. The obtained experimental data suggest the presence of compounds in the garden ruta extracts which are capable of blocking the MrsA-mediated efflux of macrolides from staphylococcal cells.

Assessment on the effect of erythromycin on the microbiome of a bioslurry pilot plant for contaminated sediment bioprocessing

Bioslurry is a microbial-based technology that uses a bioreactor to treat sediments. The role of microbial metabolic capabilities is crucial for the removal performance of this technology and those factors that can affect microbial community. Particularly, antibiotics are among the environmental emergent contaminants. In this work, the effect of erythromycin was evaluated on the removal efficiencies of total petroleum hydrocarbons (TPHs), present in real sediments. On the basis of preliminary microcosm tests, an optimal erythromycin concentration (0.5 μg mL−1) was applied to a bioslurry pilot plant, using as control condition a parallel reactor without erythromycin addition. During experimentation the removal efficiency increased in both reactors, especially in the antibiotic-containing reactor where performance removal reached 81.5 %. A metataxonomic approach, based on a Next Generation Sequencing analysis of amplicons obtained from 16S rRNA encoding gene and ITS regions, showed that the presence of erythromycin affects the dynamic changes of both eukaryotic and prokaryotic communities in the reactor, selecting bacteria capable of degrading aromatic compounds, performing dehalogenation and methane oxidation as inferred by bioinformatic analysis.

Electrocatalytic behaviour of self-assembled Cu-chitosan/f-MWCNT on glassy carbon electrode for detection of erythromycin in various samples

Although antibiotics are class of compounds that are administered to fight bacterial infections in human and animals, its abuse is ensuing its occurrence in natural resources producing drug resistant strains, which in turn affect human health. Therefore, it is important to develop rapid and effective detection techniques for such antibiotics which are contaminating various natural resources. In this study, a novel electrochemical sensor was developed for determination of one of the most used macrolide antibiotic “Erythromycin” based on self- assembled cu-chitosan/f-MWCNT modified glassy carbon electrode. The negatively charged f-MWCNT holds the positively charged chitosan and Cu2+ ions, leading to formation of Cu-chitosan/f-MWCNT/GCE. FE-SEM, FT-IR, EDS as well as electrochemical methods such as CV, DPV and EIS were used to characterize formation of Cu-chitosan/f-MWCNT/GCE at every step of fabrication. From thermo-gravimetric analysis the composite was found to be stable up to 120 °C and further heating results in breakdown of the skeletal structure between 300 °C to 500 °C. Results from Cyclic voltammetry and electrochemical impedance spectroscopy indicated that after modification, the value of charge transfer resistance (Rct) decreased, and the electron transfer kinetics increased, significantly. In comparison to bare GCE, the Cu-chitosan/f-MWCNT/GCE displayed excellent electrocatalytic activity for the oxidation of erythromycin, as indicated by an increased oxidation peak current. The differential pulse peak current was linear for erythromycin concentration from 0.5 × 10−6 to 10 × 10−6 and 10 × 10−6 to 150 × 10−6M, with LOD 0.2 × 10−6M. The sensor demonstrated high selectivity, excellent stability, and impressive repeatability, during erythromycin determination. Thus, the proposed sensor demonstrates promising analytical applicability towards erythromycin detection in various samples.

Screening for antimicrobial residues in poultry eggs in Bangladesh using Charm II radio-receptor assay technique following validation

ABSTRACT The aim of the study was to screen for the presence of antimicrobial residues in poultry eggs from Bangladesh using the Charm II radio-receptor assay in the absence of expensive confirmatory instrumentation. This was based on cut-off values as set in the validation guidelines according to Commission Decision 2002/657/EC and Commission Implementing Regulation (EU) 2021/808. Fortified eggs spiked with fixed concentrations of doxycycline, erythromycin A, sulphamethazine, and benzylpenicillin were used to determine the cut-off values and detection capabilities (CCβ). Other validation parameters included were applicability, ruggedness, and robustness. A total of 201 egg mix samples from native organic chicken, duck, and commercial farm-raised laying hens (both brown and white eggs) were tested and after analysis 13%, 10%, and 4.5% of the egg mix samples showed positive signals for sulphonamides, macrolides/lincosamides, and tetracyclines, respectively. Presence of multiple drug residues were also suspected in 11 out of 201 egg mix samples.

Exploring the combination characteristics of dissolved organic matter with erythromycin in a soil infiltration system

ABSTRACT Erythromycin (ERY), as a common macrolides antibiotic, is widely used for sterilisation and disinfection of humans or livestock whose migration and transformation in the surface water environment are significantly related to dissolved organic matter (DOM). The characteristics of DOM can be greatly influenced by the complexation between ERY with itself in soil infiltration system. Using spectroscopic techniques (excitation-emission matrices, parallel factor analysis, Fourier infrared spectroscopy, and synchronous fluorescence spectroscopies) to explore the complexation properties of each DOM component with ERY in the system. The binding order of ERY with DOM functional groups was determined by two-dimensional correlation spectroscopy combined with FTIR. The amide I band v(C = O) exhibited stronger binding affinity. After the treatment, the DOM fluorescence intensity sharply decreased and the ERY concentration declined by 88.36%. Thus, synchronous degradation may occur between them. The result of synchronous fluorescence spectroscopy integrated with two-dimensional correlation spectroscopy indicated that the complexation sequencing and ability of DOM with ERY can be changed by a soil infiltration system. There are more binding sites exhibited in DOM with ERY in effluent than influent. A protein-like component of DOM showed priority binding order and more stable binding with ERY and had the highest Log KM value of 3.61. These results demonstrated that the binding of DOM with ERY in a soil infiltration system could take out most fluorescent DOM, and reduce the concentration and risk of ERY in the surface water body.

Membrane fouling mechanism of submerged membrane bioreactor during erythromycin removal

Background: Based on the previous studies, antibiotics can have affected biological properties of biomass and fouling properties of mixed liquor in aeration tank. The present study was conducted to explore the fouling mechanisms of membrane bioreactor (MBR) system during the treatment of wastewater containing erythromycin (ERY) antibiotic under several mixed liquor suspended solids (MLSS) concentrations. Methods: A lab-scale two-chamber MBR system equipped with a polypropylene hollow fiber submerged membrane was fed with synthetic wastewater containing different initial concentrations of ERY. MBR system was operated under the constant flux mode and different MLSS concentrations (5.0-13.0 g/L) and the obtained results were evaluated using different individual and combined fouling models. Results: The variation of MLSS concentrations had not significantly affected the kind of best-fitted model. From the individual models, the standard model indicated the best performance for permeate prediction under different MLSS concentrations (R2 adj&gt;0.997). For all studied MLSS concentrations, the R2 adj values of combined fouling models were higher than 0.986 and demonstrated good fitness performance of combined models compared to individual models. Overall, the cake-intermediate model showed the lowest fitness, and cake-complete and complete-standard models were the most successful models in filtrated volume prediction in comparison with other combined fouling models. Conclusion: This study indicated that mechanistic models are suitable for fouling prediction of MBR systems in ERY removal and under a wide range of MLSS concentrations and provide valuable information on fouling mechanisms of full-scale MBR systems.