Concentrations Of Streptomycin Research Articles

Enhance the Antimycobacterial Activity of Streptomycin with Ebselen as an Antibiotic Adjuvant Through Disrupting Redox Homeostasis.

Tuberculosis (TB) remains a major health threat worldwide, and the spread of drug-resistant (DR) TB impedes the reduction of the global disease burden. Ebselen (EbSe) targets bacterial thioredoxin reductase (bTrxR) and causes an imbalance in the redox status of bacteria. Previous work has shown that the synergistic action of bTrxR and sensitization to common antibiotics by EbSe is a promising strategy for the treatment of DR pathogens. Thus, we aimed to evaluate whether EbSe could enhance anti-TB drugs against Mycobacterium marinum (M. marinum) which is genetically related to Mycobacterium tuberculosis (Mtb) and resistant to many antituberculosis drugs. Minimum inhibitory concentrations (MIC) of isoniazid (INH), rifampicin (RFP), and streptomycin (SM) against M. marinum were determined by microdilution. The Bliss Independence Model was used to determine the adjuvant effects of EbSe over the anti-TB drugs. Thioredoxin reductase activity was measured using the DTNB assay, and its effects on bacterial redox homeostasis were verified by the elevation of intracellular ROS levels and intracellular GSH levels. The adjuvant efficacy of EbSe as an anti-TB drug was further evaluated in a mouse model of M. marinum infection. Cytotoxicity was observed in the macrophage cells Raw264.7 and mice model. The results reveal that EbSe acts as an antibiotic adjuvant over SM on M. marinum. EbSe + SM disrupted the intracellular redox microenvironment of M. marinum by inhibiting bTrxR activity, which could rescue mice from the high bacterial load, and accelerated recovery from tail injury with low mammalian toxicity. The above studies suggest that EbSe significantly enhanced the anti-Mtb effect of SM, and its synergistic combination showed low mammalian toxicity in vitro and in vivo. Further efforts are required to study the underlying mechanisms of EbSe as an antibiotic adjuvant in combination with anti-TB drug MS.

A highly sensitive luminescent aptasensor utilizing MOF-74-co encapsulation of luminol in a ‘turn-on’ mode for streptomycin detection

This study focused on detecting streptomycin (STR) residues using a luminescent aptasensor encapsulated with aptamer. Utilizing MOF-74-Co with peroxidase-like activity, luminol was enclosed in its pores. The specific STR aptamer acted as a gatekeeper, ensuring excellent performance. Upon exposure to STR, the aptamers detached, releasing luminol and amplifying the luminescent signal through MOF-74-Co catalytic activity. A linear relationship between fluorescence intensity and STR concentration (50 nM ∼ 5 × 106 nM) was established, with a limit of detection of 0.065 nM. The sensor exhibited high selectivity for STR even in the presence of other aminoglycoside antibiotics. Applied to tea, egg, and honey samples, the sensor showed recovery rates of 91.38–100.2%, meeting safety standards. This MOF-based aptasensor shows promise for detecting harmful residues.

Poly-Eriochrome Black T Decorated with Nickel Hydroxide Nanoparticles Modified Electrode for the Electrochemical Detection of Streptomycin and Probing its Interaction with Double-stranded DNA

We present a simple platform of poly-eriochrome Black T decorated with nickel hydroxide nanoparticles (Ni(OH)2NPs/PEBT) for the electrocatalytic oxidation of streptomycin (STRP) and probing its interaction with double-stranded DNA (ds-DNA). The electropolymerized eriochrome Black T modified glassy carbon electrode (GCE) was used to stabilize and synthesize Ni(OH)2NPs. The oxidation of STRP on Ni(OH)2NPs/PEBT/GCE mainly proceeded as a surface mechanism with the contribution of a diffusion-controlled process. A significant catalytic oxidation current of STRP was measured from an alkaline medium. It showed a dependence on the STRP concentrations in the range of 0.1 to 1.0 mM with a detection limit of 0.04 mM. The sensor has shown good recovery (85.3% to 90.2%, with RSD range of 1.27 to 8.83%) for the detection of STRP in diluted human serum. The interaction of STRP with ds-DNA was investigated from phosphate buffer pH 7.4 (0.2 M) using different electrode modifications (PEBT/GCE, and Ni(OH)2NPs/PEBT) in addition to bare GCE using voltammetric and impedance techniques. The binding constant of the STRP-DNA complex was calculated. Under the studied conditions, the interaction of ds-DNA with STRP in solution or on the surface of PEBT/GCE demonstrates their binding in intercalative and electrostatic modes.

Changes of Sensitivity to Streptomycin in Erwinia amylovora Isolated from 2019 to 2023 in Korea

Erwinia amylovora, a causal pathogen of fire blight, has been continuously inducing damage to the apple and pear trees in South Korea since 2015. Farmers apply antibiotics during blooming season to prevent the fire blight. However, continuous use of antibiotics can induce the emergence of resistant bacteria, which consequently reduces control efficacy. In this study, we assessed the minimal inhibitory concentration (MIC) of streptomycin, using a total of 361 E. amylovora isolates that were collected from the six provinces of South Korea from 2019 to 2023. As a result, the MIC of streptomycin ranged from 0.5 to 4 µg/ml and the strA-strB genes were not identified from the isolates. The MIC was higher in the isolates from Gyeonggi-do, Gangwon-do, and Chungcheongbuk-do compared to those from other three provinces. These results may bring broad attention to the use of streptomycin and aid in developing a management protocol for the occurrence of fire blight in South Korea.

Genomic and Transcriptomic Analyses Reveal Multiple Strategies for Vibrio parahaemolyticus to Tolerate Sub-Lethal Concentrations of Three Antibiotics.

Vibrio parahaemolyticus can cause acute gastroenteritis, wound infections, and septicemia in humans. The overuse of antibiotics in aquaculture may lead to a high incidence of the multidrug-resistant (MDR) pathogen. Nevertheless, the genome evolution of V. parahaemolyticus in aquatic animals and the mechanism of its antibiotic tolerance remain to be further deciphered. Here, we investigated the molecular basis of the antibiotic tolerance of V. parahaemolyticus isolates (n = 3) originated from shellfish and crustaceans using comparative genomic and transcriptomic analyses. The genome sequences of the V. parahaemolyticus isolates were determined (5.0-5.3 Mb), and they contained 4709-5610 predicted protein-encoding genes, of which 823-1099 genes were of unknown functions. Comparative genomic analyses revealed a number of mobile genetic elements (MGEs, n = 69), antibiotic resistance-related genes (n = 7-9), and heavy metal tolerance-related genes (n = 2-4). The V. parahaemolyticus isolates were resistant to sub-lethal concentrations (sub-LCs) of ampicillin (AMP, 512 μg/mL), kanamycin (KAN, 64 μg/mL), and streptomycin (STR, 16 μg/mL) (p < 0.05). Comparative transcriptomic analyses revealed that there were significantly altered metabolic pathways elicited by the sub-LCs of the antibiotics (p < 0.05), suggesting the existence of multiple strategies for antibiotic tolerance in V. parahaemolyticus. The results of this study enriched the V. parahaemolyticus genome database and should be useful for controlling the MDR pathogen worldwide.

Gold screen-printed electrodes coupled with molecularly imprinted conjugated polymers for ultrasensitive detection of streptomycin in milk

Antibiotic resistance is a global health threat, challenging traditional treatments and complicating the food safety process. This study introduces an electrochemical detection method for streptomycin sulfate, utilizing gold screen-printed electrodes (Au-SPE) functionalized via electropolymerization of a custom-made naphthalene diimide-based conjugated monomer (Th2-NDI-PIA). This modification creates specific binding sites for streptomycin, allowing rapid detection of the antibiotic. The sensor's response to different concentrations of streptomycin was studied via Differential Pulse Voltammetry (DPV) in a wide linear range from 10-13 M to 10-9 M, with a limit of detection (LoD) of 0.190 ± 0.005 pM. The imprinted electrode demonstrates selectivity to other antibiotics, but also to common interferents that can be found in milk such as lactose, glucose, riboflavin, and bisphenol A. Successful proof-of-principle in whole cow milk highlights the sensor's efficacy in detecting antibiotic residues in food samples, offering a promising alternative for a rapid and portable detection technique.

Does selective digestive decontamination (SDD) increase antibiotic resistance? Long-term comparison of two intensive care units (with and without SDD) of the same tertiary hospital

PurposeThe aim of this study was to to compare the antimicrobial resistance rate and its relationship with the antibiotic consumption in two separate Intensive Care Units (ICUs) of the same hospital, one with and other without selective decontamination of the digestive tract (SDD).MethodsWe performed a retrospective study in the two ICUs of the Araba University Hospital. Trauma and neurosurgical patients are admitted to the SDD-ICU, and general digestive surgery patients go to the no SDD-ICU. From 2014 to 2018 we analyzed the number of isolates, and the bacterial resistance trends of 47 antimicrobial-microorganism combinations. Additionally, antimicrobial consumption was estimated in both ICUs. Resistance rates were also compared with those reported in ENVIN-HELICS Spanish national registry.ResultsIn the ICU with SDD protocol, there was a significant decrease in the resistance of E. coli to amoxicillin/clavulanic acid and in the resistance of E. faecalis to high concentration of gentamycin and high concentration of streptomycin. A significant increase of resistance of Staphylococcus coagulasa negative (CoNS) to linezolid in the no SDD-ICU was also detected. Overall, the level of resistance in the SDD-ICU was lower or of the same order than in the ICU without SDD and that reported in the Spanish national registry.ConclusionsSDD had neither a clinically relevant impact on emergence and spread of resistance, nor in the overall systemic antimicrobial use. The patient type rather than the SDD protocol showed to condition the ecology and therefore, the resistance rate in the ICUs.

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.

Biosynthesis of Octacosamicin A: Uncommon Starter/extender Units and Product Releasing via Intermolecular Amidation.

Octacosamicin A is an antifungal metabolite featuring a linear polyene-polyol chain flanked by N-hydroxyguanidine and glycine moieties. We report here that sub-inhibitory concentrations of streptomycin elicited the production of octacosamicin A in Amycolatopsis azurea DSM 43854T . We identified the biosynthetic gene cluster (oca BGC) that encodes a modular polyketide synthase (PKS) system for assembling the polyene-polyol chain of octacosamicin A. Our analysis suggested that the N-hydroxyguanidine unit originates from a 4-guanidinobutyryl-CoA starter unit, while the PKS incorporates an α-hydroxyketone moiety using a (2R)-hydroxymalonyl-CoA extender unit. The modular PKS system contains a non-canonical terminal module that lacks thioesterase (TE) and acyl carrier protein (ACP) domains, indicating the biosynthesis is likely to employ an unconventional and cryptic off-loading mechanism that attaches glycine to the polyene-polyol chain via an intermolecular amidation reaction.

Three genes controlling streptomycin susceptibility in Agrobacterium fabrum.

Streptomycin (Sm) is a commonly used antibiotic for its efficacy against diverse bacteria. The plant pathogen Agrobacterium fabrum is a model for studying pathogenesis and interkingdom gene transfer. Streptomycin-resistant variants of A. fabrum are commonly employed in genetic analyses, yet mechanisms of resistance and susceptibility to streptomycin in this organism have not previously been investigated. We observe that resistance to a high concentration of streptomycin arises at high frequency in A. fabrum, and we attribute this trait to the presence of a chromosomal gene (strB) encoding a putative aminoglycoside phosphotransferase. We show how strB, along with rpsL (encoding ribosomal protein S12) and rsmG (encoding a 16S rRNA methyltransferase), modulates streptomycin sensitivity in A. fabrum. IMPORTANCE The plant pathogen Agrobacterium fabrum is a widely used model bacterium for studying biofilms, bacterial motility, pathogenesis, and gene transfer from bacteria to plants. Streptomycin (Sm) is an aminoglycoside antibiotic known for its broad efficacy against gram-negative bacteria. A. fabrum exhibits endogenous resistance to somewhat high levels of streptomycin, but the mechanism underlying this resistance has not been elucidated. Here, we demonstrate that this resistance is caused by a chromosomally encoded streptomycin-inactivating enzyme, StrB, that has not been previously characterized in A. fabrum. Furthermore, we show how the genes rsmG, rpsL, and strB jointly modulate streptomycin susceptibility in A. fabrum.

Development of Novel Peptide-Modified Silver Nanoparticle-Based Rapid Biosensors for Detecting Aminoglycoside Antibiotics.

The detection and monitoring of aminoglycoside antibiotics (AGAs) have become of utmost importance due to their widespread use in human and animal therapy, as well as the associated risks of exposure, toxicity, and the emergence of antimicrobial resistance. In this study, we successfully synthesized casein hydrolysate peptides-functionalized silver nanoparticles (CHPs@AgNPs) and employed them as a novel colorimetric analytical platform to demonstrate remarkable specificity and sensitivity toward AGAs. The colorimetric and spectral response of the CHPs@AgNPs was observed at 405 and 520 nm, showing a linear correlation with the concentration of streptomycin, a representative AGA. The color changes from yellow to orange provided a visual indication of the analyte concentration, enabling quantitative determination for real-world samples. The AgNP assay exhibited excellent sensitivity with dynamic ranges of approximately 200-650 and 100-700 nM for streptomycin-spiked tap water and dairy whey with limits of detection found to be ∼98 and 56 nM, respectively. The mechanism behind the selective aggregation of CHPs@AgNPs in the presence of AGAs involves the amine groups of the target analytes acting as molecular bridges for electrostatic coupling with hydroxyl or carboxyl functionalities of adjacent NPs, driving the formation of stable NP aggregates. The developed assay offers several advantages, making it suitable for various practical applications. It is characterized by its simplicity, rapidity, specificity, sensitivity, and cost-effectiveness. These unique features make the method a promising tool for monitoring water quality, ensuring food safety, and dealing with emergent issues of antibiotic resistance.

Potential of bacteriophage PCT27 to reduce the use of agrochemicals to control Pectobacterium carotovorum subsp. Carotovorum in Chinese cabbage (Brassica pekinensis)

As antimicrobial resistance (AMR) continues to spread among bacteria and poses a serious threat to global health, the indiscriminate use of antibiotics in various fields, including agriculture, should be avoided. Here, we isolated a novel bacteriophage (phage), PCT27, specific for Pectobacterium carotovorum subsp. carotovorum (Pcc), a phytopathogen responsible for soft rot of crops, and investigated its potential as an adjunct to reduce the use of agrochemicals in Pcc control. Phage PCT27, which belongs to the family Autographiviridae, inhibited in vitro growth of Pcc within 1 h of infection by recognizing colanic acid as a host receptor. More than 90% of the virions rapidly adsorbed to the host cells within 3 min, supporting the efficient control of Pcc by PCT27. PCT27 supplementation reduced the minimum inhibitory concentration of streptomycin by 50% for Pcc control in vitro. Accordingly, PCT27 successfully complemented an antibiotic-based agrochemical in preventing Pcc infection in Chinese cabbage leaves and seedlings by reducing the dose of the agrochemical by a quarter. As a biocontrol agent for Pcc that complements agrochemicals, PCT27 can not only prevent economic losses due to crop decay but would also contribute to addressing the AMR crisis for sustainable agriculture and environmental safety.

The Effect Of Streptomycin And Clindamycin On Dnase I Activity On The Quality Of Dna Of Salivary Origin

Deoxyribonucleic acid (DNA) contains genetic material with all an individual’s information. Saliva has the potential to be a good source of human DNA. When compared to blood sampling, saliva is easier to collect and the collection process is non-invasive. However, human DNA collected from saliva has the potential to be degraded due to deoxyribonuclease (DNase) activity in saliva. DNase activity can be inhibited by antibiotics, such as aminoglycoside antibiotics and lincomycin derivatives. This study aimed to determine the effect of streptomycin and clindamycin on DNAse I activity against the quality of human genomic DNA from saliva. The sampling technique was that samples were collected from 9 subjects with each subject flowing into a saliva pot. Before saliva collection, subjects were asked to rinse their mouth with a solution of chlorhexidine gargle (Listerin™) for 30 seconds, then the samples were divided into four groups. The average concentration of DNA extracted from the spin-column method was 32.91 g/mL (7.10-99.45 g/mL) while the average purity was 1.813 g/mL (1.639-2.043 g/mL). With clindamycin treatment, PCR was able to amplify the human NOTCH2 gene (~704 bp) while various concentrations of streptomycin produced multiple bands of ~100 bp. The concentration of 3.2 mM clindamycin effectively inhibits DNAse I activity and can amplify the human NOTCH2 gene while streptomycin cannot protect.

A Case of Mycobacteriosis in Cultured Japanese Seabass (Lateolabrax japonicus) in Southern China

Japanese seabass (Lateolabrax japonicus) is an important species of cultured marine fish with high economic value in China. Nevertheless, from May to November 2019, mass mortality among cultured Japanese seabass occurred in Zhuhai City, Guangdong Province of China. Approximately 0.2–0.5% mortality was recorded daily, and the cumulative mortality was up to 30% during this disease outbreak. In this study, the clinical signs and pathological characteristics of diseased fish were investigated. Furthermore, the pathogenicity and antibiotic sensitivity of identified pathogenic bacteria from diseased fish were analyzed. The infected fish showed clinical signs of uncoordinated swimming; anorexia; pigment changes; and a number of 1–5 mm grayish-white nodules in the liver, spleen, and kidney tissues was also found. A bacterial strain, which was designated as ZHLJ2019, was isolated from the diseased fish. To ensure that ZHLJ2019 isolate was the causative agent, a Koch postulate trial was performed. Healthy Japanese seabass were infected by the intraperitoneal injection of 5 × 104, 5 × 105 and 5 × 106 CFU/fish, and cumulative mortalities within 42 days were 75%, 90%, and 100%, respectively. The bacteria colony had traditional morphological and biochemical characteristics similar to that of Mycobacterium marinum. Phylogenetic molecular analyses of 16S rRNA, rpoB, hsp65, erp, and ITS genes confirmed that the isolated strain ZHLJ2019 was M. marinum. The granulomatous inflammation in internal organs of Japanese seabass naturally and experimentally infected with ZHLJ2019 isolate was consistent with the classic pathological features of mycobacteriosis. Drug susceptibility of ZHLJ2019 isolate to 11 antibiotics was determined by broth dilution method in vitro. The minimum inhibitory concentrations (MICs) of minocycline, rifampicin, ethambutol, isoniazid, streptomycin, doxycycline hydrochloride, kanamycin sulfate, levofloxacin, roxithromycin, and prothionamide against the strain ZHLJ2019 were 4, 2, 8, 4, 16, 8, 8, 8, 4, and 8 μg/mL, respectively. The results of this study suggest that M. marinum is the causal agent responsible for the morbidity and mortality of Japanese seabass cultured in intensive brackish water dirt ponds in southern China.

Delivery of streptomycin to the rat colon by use of electrospun nanofibers

Drug-loaded electrospun nanofibers are potential drug carrier systems that may optimize disease treatment while reducing the impact on commensal microbes. The feasibility of streptomycin-loaded pullulan nanofibers fabricated from a green electrospinning procedure using water as the solvent was assessed. We conducted a rat study including a group treated with streptomycin-loaded nanofibers (STR-F, n = 5), a group treated with similar concentrations of streptomycin in the drinking water (STR-W, n = 5), and a non-treated control group (CTR, n = 5). Streptomycin was successfully loaded into nanofibers and delivered by this vehicle, which minimized the quantity of the drug released in the ileal compartment of the gut. Ingested streptomycin-resistant E. coli colonized of up to 106 CFU/g feces, revealing a selective effect of streptomycin even when given in the low amounts allowed by the nanofiber-based delivery. 16S amplicon sequencing of the indigenous microbiota revealed differential effects in the three groups. An increase of Peptostreptococcaceae in the cecum of STR-F animals may indicate that the fermentation of nanofibers directly or indirectly promoted growth of bacteria within this family. Our results elucidate relevant properties of electrospun nanofibers as a novel vehicle for delivery of antimicrobials to the large intestine.

Physiological responses and antibiotic-degradation capacity of duckweed (Lemna aequinoctialis) exposed to streptomycin.

Aquatic plants are constantly exposed to various water environmental pollutants. Few data on how antibiotics affect duckweed health and its removal ability. The aim of this study was to investigate the impact of streptomycin on the physiological change and uptake capability in duckweed (Lemna aequinoctialis) after exposure at different time points (0, 5, 10, 15 and 20 days). Duckweeds were exposed to streptomycin at a range of concentrations (0.1-10 mM). Results indicated that the high streptomycin concentrations (≥1 mM) resulted in a lower duckweed biomass (21.5-41.5%), RGR (0.258-0.336 g d-1), decrease in total Chl and increase in carotenoids. Antioxidative enzymes, including CAT (18-42.88 U mg protein-1), APX (0.41-0.76 U mg protein-1), and SOD (0.52-0.71 U mg protein-1) were found to accumulate in the streptomycin groups in comparison to the control group. The significant reduction (72-82%) in streptomycin content at 20 d compared to the control (40-55%) suggested that duckweed has a high ability in removing streptomycin. Transcriptome analysis showed that the secondary metabolic pathways including phenylpropanoid biosynthesis and flavonoid biosynthesis were significantly upregulated in the streptomycin setup compared to the control. Therefore, our findings suggested that duckweed can contribute to the streptomycin degradation, which should be highly recommended to the treatment of aquaculture wastewater and domestic sewage.

Fabrication of anti-fouling polyamide nanofiltration membrane by incorporating streptomycin as a novel co-monomer

Polyamide (PA) thin-film composite (TFC) nanofiltration (NF) membrane has extremely broad application prospects in separation of monovalent/divalent inorganic salts mixed solution. However, membrane fouling is the main obstacle to the application of PA TFC NF membrane. Streptomycin (SM) is a hydrophilic antibiotic containing a large number of hydroxyl and amino groups. In this work, the NF membrane was prepared via interfacial polymerization (IP) between trimesoyl chloride (TMC) in the organic phase and SM/piperazine (PIP) mixture in the aqueous phase. The NF membrane structure and performance were characterized in detail. The results showed that SM successfully participated in the IP. The negative charge and hydrophilicity of membrane surface were improved. The prepared membrane exhibited good anti-adhesion and anti-bacterial performance. Additionally, when the SM concentration was 2%, the prepared membrane exhibited the optimal permselectivity. The water permeance was 89.4 L·m –2 ·h –1 ·MPa –1 . The rejection of NaCl and Na 2 SO 4 were 17.17% and 97.84%, respectively. The NaCl/Na 2 SO 4 separation factor of the SM2-PIP/TMC membrane in 1000 mg·L –1 NaCl and 1000 mg·L –1 Na 2 SO 4 mixed solution was 40, which was 3.3 times that of PIP/TMC membrane. It indicated that SM2-PIP/TMC demonstrated excellent monovalent/divalent salts separation performance. This work provided an easy and effective approach to preparing anti-fouling NF membrane while possessing superior monovalent/divalent salts separation performance.

Antifouling streptomycin-based nanofiltration membrane with high permselectivity for dye/salt separation

Nanofiltration (NF) membrane with excellent dye/salt permselectivity and anti-fouling performance is highly desired for the separation of dye/salt mixture in dye wastewater treatment. In this work, the antibacterial NF membrane with high permselectivity and anti-fouling performance was prepared by using a hydrophilic antibiotic, streptomycin (SM) with abundant amino and hydroxyl groups, as the aqueous monomer via interfacial polymerization (IP) with trimesoyl chloride (TMC). The as-prepared antibiotic membrane had a hydrophilic and highly smooth surface, which was beneficial to the membrane anti-fouling performance. The membrane performance was optimized by tuning the concentration of SM, and the optimized membrane with desirable water permeance of 23.5 L·m−2·h−1·bar−1 had excellent dyes rejections (the rejections of Direct red 23 (DR 23), Congo red (CR), Acid red 66 (AR 66), Victoria blue B (VB), and Chrome black T (CBT) were 99.7%, 99.6%, 99.0%, 99.5%, 99.7%, respectively) and low salts rejection (the rejections of NaCl and Na2SO4 were 1.9% and 4.5%, respectively). The optimized membrane also showed excellent separation performance to salt/dye mixed solutions and operational stability. This newly streptomycin-based NF membrane showed excellent application potential in the dye wastewater treatment.

Herbal Antagonism of a Superbug – A Novel Approach

Background: This study was conducted to herbally antagonize the growth of a multi drug resistant Pseudomonas sp using ethanolic carrot rough fiber extractive. Materials and methods: The isolated strain of Pseudomonas sp was subjected to treatment with 5 different antibiotics-Chloramphenicol, penicillin, streptomycin, amoxycillin clavulanate along with monocef up to a concentration of 500µg/ml. The isolated organism was also treated with a mutagen Ethyl methane sulphonate. The antimicrobial property of the ethanolic carrot rough fiber extractive was tested by well diffusion method. MIC study of the ethanolic carrot rough fiber extractive was also performed. Result: The isolated strain was found to be resistant against 5 different antibiotics-Chloramphenicol, penicillin, streptomycin, amoxycillin clavulanate along with monocef up to a concentration of 500µg/ml. This organism was also found to grow at 44°C without any pigment production. This Pseudomonas sp also possess the ability of biofilm formation and antagonize the growth of other microbial population. There is reduced growth of this superbug under the influence of Ethyl methane sulphonate. It also became susceptible to the antibiotics monocef, streptomycin and higher concentration of amoxicillin. So the isolated strain is very much prone to induced mutation. The growth of this multi drug resistant strain of Pseudomonas sp has been antagonized by the ethanolic carrot fibre extractive. MIC study of the ethanolic carrot rough fibre extractive was performed which revealed that the MIC lies between 125µl-150µl i.e., 216.6-260mg/ml concentration of the extract. Conclusion: The ethanolic carrot rough fibre extractive has been found to antagonize the growth of the multidrug resistant Pseudomonas sp.

HopE and HopD Porin-Mediated Drug Influx Contributes to Intrinsic Antimicrobial Susceptibility and Inhibits Streptomycin Resistance Acquisition by Natural Transformation in Helicobacter pylori.

ABSTRACTHelicobacter pylori is a human pathogen competent for natural transformation. Intrinsic and acquired antibiotic resistance contribute to the survival and multiplication of H. pylori under antibiotics. While drug-resistance dissemination by natural transformation (NT)-mediated horizontal gene transfer remains poorly understood in H. pylori. The purpose of the study was to investigate the role of H. pylori porins (HopA, HopB, HopC, HopD, and HopE) in the intrinsic antibiotic resistance and to preliminarily reveal the potential effect of HopE and HopD porins in streptomycin resistance acquisition after NT in the presence of antibiotics. Using traditional antibiotic susceptibility tests and growth curve analysis, we found the MIC values of metronidazole, clarithromycin, levofloxacin, tetracycline, rifampin, and streptomycin in mutants lacking HopE and/or HopD were significantly elevated compare to those in wild-type strain. The quantitative analysis of the tetramethyl rhodamine isothiocyanate (TRITC)-labeled streptomycin accumulation at the single-cell level showed reduced streptomycin intracellular fluorescence in ΔhopE and ΔhopD mutant cells. Furthermore, in the presence of translation-inhibiting antibiotic streptomycin, the resistance acquisition frequency was decreased in the wild-type strain, which could be reversed by mutants lacking HopE and HopD that restored relatively high resistance acquisition frequencies. By transforming a pUC19-rpsLmut-sfgfp linear plasmid carrying a streptomycin conferring mutation, we observed that the impaired ability of rpsLmut synthesis in the wild-type strain was restored in the ΔhopE and ΔhopD mutant transformants. Our study revealed that in the presence of streptomycin, resistance acquisition at least partially relied on the deletion of the hopE and hopD genes, because their loss reduced streptomycin concentration in the cell and thus restored the expression of the resistance-conferring gene, which was inhibited by streptomycin in wild-type strain. The loss of HopE and HopD influx activity may also preserve resistance acquisition by transformation in the presence of antibiotics with other modes of action.IMPORTANCE Helicobacter pylori is constitutively competent for natural transformation (NT) and possesses an efficient system for homologous recombination, which could be utilized to study the NT-mediated horizontal gene transfer induced antibiotic resistance acquisition. Bacterial porins have drawn renewed attention because of their crucial role in antibiotic susceptibility. From the perspective of porin-mediated influx in H. pylori, our study preliminarily revealed the important role of HopE and HopD porins not only in preserving the intrinsic susceptibility to specific antibiotic but also in evading acquired antibiotic resistance by NT in the presence of translation-inhibiting antimicrobial. Therefore, the loss of HopE or HopD porin in H. pylori genomes, combined with the large number of secreted or cell-free genetic elements carrying mutations conferring antibiotic resistance, may raise the possibility that this mechanism plays a potential role in the propagation of antibiotic resistance within H. pylori communities.