A novel method to prepare guanidine substituted aminoglycoside derivatives was developed.Free guanidine reacted with Cbz-protected aminoglycosides to produce guanidinylcarbonyl substituted derivatives.A methoxycarbony...A novel method to prepare guanidine substituted aminoglycoside derivatives was developed.Free guanidine reacted with Cbz-protected aminoglycosides to produce guanidinylcarbonyl substituted derivatives.A methoxycarbonyl-protected intermediate was isolated,and the mechanism of guanidinylcarbonyl modification was proposed.With this method,six per- or part-guanidylcarbonyl substituted aminoglycosides were successfully obtained in good yields.Their in vitro antibacterial activities were essayed.展开更多
A series of urea-linked hydroxyl-alkylamine derivatives of aminoglycosides have been obtained by modification of neamine （1）, kanamycin （2） and ribostamycin （3） at 1, 6＇ and 3 N-sites, respectively, through se...A series of urea-linked hydroxyl-alkylamine derivatives of aminoglycosides have been obtained by modification of neamine （1）, kanamycin （2） and ribostamycin （3） at 1, 6＇ and 3 N-sites, respectively, through selective cyclization and nucleophilic ring-opening of cyclic carbamates. All the products showed no noticeable activity in the antibiotic test in vitro. The result suggests that the urea-linked hydroxyl-alkylamine derivatives of aminoglycosides may not be suitable structures for the enhancement of antibiotic activity.展开更多
Aminoglycosides(Am An) are widely used for their great efficiency against gram-negative bacterial infections. However, they can also induce ototoxic hearing loss, which has affected millions of people around the world...Aminoglycosides(Am An) are widely used for their great efficiency against gram-negative bacterial infections. However, they can also induce ototoxic hearing loss, which has affected millions of people around the world. As previously reported, individuals bearing mitochondrial DNA mutations in the 12 S rRNA gene, such as m.1555A>G and m.1494C>T, are more prone to Am An-induced ototoxicity. These mutations cause human mitochondrial ribosomes to more closely resemble bacterial ribosomes and enable a stronger aminoglycoside interaction. Consequently,exposure to Am An can induce or worsen hearing loss in these individuals. Furthermore, a wide range of severity and penetrance of hearing loss was observed among families carrying these mutations. Studies have revealed that these mitochondria mutations are the primary molecular mechanism of genetic susceptibility to Am An ototoxicity, though nuclear modifier genes and mitochondrial haplotypes are known to modulate the phenotypic manifestation.展开更多
Objective:To explore the antiviral activity of antibiotic compounds,mainly aminoglycosides and tetracyclines against Japanese encephalitis virus(JEV) induced infection in vitro.Methods:Antiviral activity were evaluate...Objective:To explore the antiviral activity of antibiotic compounds,mainly aminoglycosides and tetracyclines against Japanese encephalitis virus(JEV) induced infection in vitro.Methods:Antiviral activity were evaluated against JEV using cytopathic effect inhibition assay,virus yield reduction assay,caspase 3 level,extracellular viral detection by antigen capture ELISA and viral RNA levels.Roults:JEV induced cytopathic effect along with reduction of viral progeny plaque formation indicated antiviral potential of the compounds suggesting that antibiotics had broad spectrum activity.Doxycycline and kanamycin administration in dose dependent manner declined viral RNA replication.Conclusions:The present study shows kanamycin and doxycyclinc can affect virion structure and alter replication causing inhibition of JEV induced pathogenesis in vitro.展开更多
Shigellosis causes diarrheal disease in humans in both developed and developing countries, and multi-drug resistance in Shigella is an emerging problem. Understanding changing resistance patterns is important in deter...Shigellosis causes diarrheal disease in humans in both developed and developing countries, and multi-drug resistance in Shigella is an emerging problem. Understanding changing resistance patterns is important in determining appropriate antibiotic treatments. This meta-analysis systematically evaluated aminoglycoside resistance in Shigella. A systematic review was constructed based on MEDLINE and EMBASE databases. Randomeffect models or fixed-effect models were used based on P value considering the possibility of heterogeneity between studies for meta-analysis. Data manipulation and statistical analyses were performed using software STATA 11.0. By means of meta-analysis, we found a lower resistance to three kinds of aminoglycosides in the Europe-America areas during the 12 year study period than that of the Asia-Africa areas. Kanamycin resistance was observed to be the most common drug resistance among Shigella isolates with a prevalence of 6.88% （95%CI： 6.36%-7.43%）. Comparison of data from Europe-America and Asia-Africa areas revealed that Shigella flexneri resistance was greater than the resistance calculated for Shigella sonnei. Importantly, Shigella sonnei has played a significant role in aminoglycoside-resistance in recent years. Similarly, data showed that resistance to these drugs in children was higher than the corresponding data of adults. In conclusion, aminoglycoside-resistant Shigella is not an unusual phenomenon worldwide. Distribution in Shigella resistance differs sharply based on geographic areas, periods of time and subtypes. The results from the present study highlight the need for con- tinuous surveillance of resistance and control of antibiotic usage.展开更多
The mitochondrial 12S rRNA has been shown to be the hot spot for mutations associated with both aminoglycoside-induced and non-syndromic hearing loss. Of all the mutations, the homoplasmic A1555G and C1494T mutations ...The mitochondrial 12S rRNA has been shown to be the hot spot for mutations associated with both aminoglycoside-induced and non-syndromic hearing loss. Of all the mutations, the homoplasmic A1555G and C1494T mutations at a highly conserved decoding region in the 12S rRNA have been associated with aminoglycoside-induced and non-syndromic hearing loss in many families worldwide. The A1555G or C1494T mutation is expected to form novel 1494C-G1555 or 1494U-A1555 base-pair at the highly conserved A-site of 12S rRNA. These transitions make the secondary structure of this RNA more closely resemble the corresponding region of bacterial 16S rRNA. Thus, the new U-A or G-C pair in 12S rRNA created by the C1494T or A1555G transition facilitates the binding of aminoglycosides, thereby accounting for the fact that the exposure to aminoglycosides can induce or worsen hearing loss in individuals carrying these mutations. Furthermore, the growth defect and impairment of mitochondrial translation were observed in cell lines carrying the A1555G or C1494T mutation in the presence of high concentration of aminoglycosides. In addition, nuclear modifier genes and mitochondrial haplotypes modulate the phenotypic manifestation of the A1555G and C1494T mutations. These observations provide the direct genetic and biochemical evidences that the A1555G or C1494T mutation is a pathogenic mtDNA mutation associated with aminoglycoside-induced and nonsyndromic hearing loss. Therefore, these data have been providing valuable information and technology to predict which individuals are at risk for ototoxicity, to improve the safety of aminoglycoside antibiotic therapy, and eventually to decrease the incidence of deafness.展开更多
Objective To study presynaptic alternations of cochlear ribbons arising from aminoglycoside ototoxic stimuli in C57BL/6J mice. Methods Animals were injected with low dose gentamicin (100 mg/kg/day) for 14 days, From t...Objective To study presynaptic alternations of cochlear ribbons arising from aminoglycoside ototoxic stimuli in C57BL/6J mice. Methods Animals were injected with low dose gentamicin (100 mg/kg/day) for 14 days, From the 14th to 28th days, the mice were maintained free of gentamicin treatment. Immunohisto-chemistry labeling was employed to trace RIBEYE, a major presynaptic componment of ribbon synapses. RIBEYE/CtBP2 expression levels were assessed and compared with hearing threshold shifts. Auditory func-tion was assessed by auditory brainstem responses. The stereocilia of outer hair cells (OHCs) and IHCs was examined by scanning electron microscopy (SEM). Results Hearing thresholds were elevated with peak hearing loss observed on the 7th day after gentamicin exposure, followed by improvement after the 7th day. RIBEYE/CtBP2 expression directly correlated with observed hearing threshold shifts. Strikingly, we did not see any obvious changes in stereocilia in both OHCs and IHCs until the 28th day. Mild changes in stereocil-ia were only observed in OHCs on the 28th day. Conclusions These findings indicate that presynapse co-chlear ribbons, rather than stereocilia, may be sensitive to aminoglycoside ototoxic exposure in mice cochle-ae. A pattern of RIBEYE/CtBP2 expression changes seems to parallel hearing threshold shifts and suggests presynaptic response properties to lower dosage of aminoglycoside ototoxic stimuli.展开更多
To investigate the underlying mechanism of the exacerbation of myasthenia gravis by aminoglycoside antibiotics. C57/BL6 mice were immunized with acetylcholine receptor (AChR), extracted from electric organ of Narcine ...To investigate the underlying mechanism of the exacerbation of myasthenia gravis by aminoglycoside antibiotics. C57/BL6 mice were immunized with acetylcholine receptor (AChR), extracted from electric organ of Narcine timilei according to Xu Haopeng's methods, in complete Fruend's adjuvant (CFA) to establish experimental autoimmune myasthenia gravis (EAMG). EAMG mice were divided randomly into 5 groups: MG group, NS group and three antibiotics groups. The clinical symptom scores of mice were evaluated on d7 after the last immunization and d14 of antibiotics treatment. Repetitive nerve stimulation (RNS) was performed and the levels of anti-AChR antibody (AChR-Ab) were tested at the same time. The mean clinical symptom grades of gentamycin group (1.312, 2.067), amikacin group (1.111, 1.889) and etimicin group (1.263, 1.632) were significantly higher than those of MG group (1.000, 1.200) (P<0.05). The positive rates of RNS of three antibiotics groups were 69.23 %, 58.82 % and 63.16 % respectively, which were significantly higher than those of MG group and NS group (40.00 %, 40.00 %, P<0.05). The AChR-Ab level in serum and the expression of AChR on neuromuscular junction (NMJ) of mice in three antibiotics groups were also higher than those of MG group. Our results indicated that aminoglycoside antibiotics could aggravate the symptom of myasthenia gravis. The exacerbation of myasthenia gravis by these antibiotics probably involves competitively restraining the release of acetylcholine from presynaptic membrane, impairing the depolarization of postsynaptic membrane, depressing the irritability of myocyte membrane around the end-plate membrane and consequently leading to the blockade of neuromuscular junction.展开更多
The Pharmacokinetics informations of aminoglycosides, their monograph and clinical Pharmacokinetics parameters are reported in this review. The Aminoglycosides are highly polarity and in reserve for serious infections...The Pharmacokinetics informations of aminoglycosides, their monograph and clinical Pharmacokinetics parameters are reported in this review. The Aminoglycosides are highly polarity and in reserve for serious infections caused by aerobic gram negative bacteria and some gram positive bacteria but their toxicity are major limitations in clinical use.展开更多
Aminoglycosides are a family of antibiotics with important applications in veterinary medicine. Their ionic character, the similarity structures and the high polarity due to the presence of two or more amino and hydro...Aminoglycosides are a family of antibiotics with important applications in veterinary medicine. Their ionic character, the similarity structures and the high polarity due to the presence of two or more amino and hydroxyl groups cause a difficulty in separation and make these compounds poorly retained on the reversed phase column. An analytical method for the separation and detection of 12 aminoglycosides has been optimized using two kinds of chromatographic conditions (HILIC, Ion pairing). In Hydrophilic Interaction, ZIC_HILIC column was used, by which the following parameters for the mobile phase were evaluated: concentration of ammonium acetate buffer, percentage of formic acid and effect of acid type. The maximum and adequate concentration of ammonium acetate for the majority of analytes was set to 30 mM. The percentage 0.1% of formic acid increases the response for the majority of analytes. On the other side, the use of 0.1% of trifluoroacetic acid improves the response when compared with the response obtained with 0.1% of formic acid except for Spectinomycin Dihydrostreptomycin and Streptomycin. For ion pairing chromatography, the concentration of pentafluoropropionic acid was tested and the greatest value appeared to be 9.2 mM. Therefore, the comparison between the two separation methods shows that the response area of the majority of analytes tested increases when using the ion pair mode. Also, the high value of S/N and the lower detection limit (5 - 15 μg m·L﹣1 for most aminoglycosides studied make the ion pairing method more preferable than HILIC interaction.展开更多
For the purpose of seeking new antibiotics,researchers usually modify the already-existing ones.However,this strategy has been extensively used and is close to its limits,especially in the case of aminoglycosides,and ...For the purpose of seeking new antibiotics,researchers usually modify the already-existing ones.However,this strategy has been extensively used and is close to its limits,especially in the case of aminoglycosides,and it is difficult to find a proper aminoglycoside antibiotic for novel modification.In this paper,we reported the design,synthesis,and evaluation of a series of 5-epi-neamine derivatives based on the structural information of bacterial 16S RNA A-site binding with aminoglycosides.Bioassay results showed that our design strategy was feasible.Our study offers a new way to search for structurally novel aminoglycosides.Meanwhile,our study provides valuable structure-activity relationship information,which will lead to better understanding and exploitation of the drug target,and improved development of new aminoglycoside antibiotics.展开更多
A novel method to prepare guanidine substituted aminoglycoside derivatives was developed. Free guanidine reacted with Cbz-protected aminoglyeosides to produce guanidinylearbonyl substituted derivatives. A methoxycarbo...A novel method to prepare guanidine substituted aminoglycoside derivatives was developed. Free guanidine reacted with Cbz-protected aminoglyeosides to produce guanidinylearbonyl substituted derivatives. A methoxycarbonyl-protected intermediate was isolated, and the mechanism of guanidinylcarbonyl modification was proposed. With this method, six per- or part- guanidylcarbonyl substituted aminoglycosides were successfully obtained in good yields. Their in vitro antibacterial activities were essayed.展开更多
Aminoglycosides are one of the categories of antibiotics most frequently used in treating several cattle diseases at the Central Cattle Breeding and Dairy Farm (CCBDF), Savar,Dhaka,Bangladesh. Untreated veterinary cli...Aminoglycosides are one of the categories of antibiotics most frequently used in treating several cattle diseases at the Central Cattle Breeding and Dairy Farm (CCBDF), Savar,Dhaka,Bangladesh. Untreated veterinary clinical healthcare waste (VCHW) of diseased cattle at CCBDF which directly disposed to surrounding may contribute to the antibiotic resistant bacteria pollution (ARB) pollution. The investigation analyses the role of VCHW of CCBDF in spreading ARB. Here we studied:1) veterinary clinical data and antibiotics treatment history;2) total and resistant bacteria counts in fecal samples of healthy and diseased cattles as well as VCHW of CCBDF;and 3) finally, data analysis to estimate the burden of VCHW of CCBDF in the pollution of environment with aminoglycoside antibiotics resistant bacteria. The results conclusively demonstrate the spread of 3 different aminoglycoside antibiotics, namely genta- mycin, kanamycin and streptomycin resistant bacte- ria in the surrounding environment alarmingly with high significant value (p < 0.01 - 0.05). This study re- veals the risks to the cattle as well as public health posed by the random VCHW disposal at the CCBDF, Bangladesh.展开更多
Context: Multidrug-resistant tuberculosis (MDR-TB) remains a major public health problem in developing countries such as the Democratic Republic of Congo (DRC), which continues to face the emergence of MDR-TB cases. B...Context: Multidrug-resistant tuberculosis (MDR-TB) remains a major public health problem in developing countries such as the Democratic Republic of Congo (DRC), which continues to face the emergence of MDR-TB cases. Because of the ototoxic effects of AGs, the World Health Organization (WHO) has recommended the introduction of the bedaquiline regimen. However, very few data are available regarding the susceptibility of bedaquiline to induce hearing loss, hence the present study set out to compare the AG-based regimen and the bedaquiline-based regimen in the occurrence of hearing loss in MDR-TB patients. Methods: This is a prospective multicenter cohort study that included 335 MDR-TB patients, performed in Kinshasa (DRC) during the period from January 2020 to January 2021. Sociodemographic, clinical, biological and audiometric data were analyzed using Stata 17. Repeated-measures analysis of variance was used to compare changes in the degree of hearing loss over time between the two groups of patients on AG and bedaquiline regimens. The double-difference method was estimated using regression with fixed-effects. A p value < 0.05 was considered the threshold for statistical significance. Results: The degree of hearing loss was similar between the two groups at the first month [AGs (28 dB) vs BDQ (30 dB);p = 0.298]. At six months, the mean degree of hearing loss was significantly greater in the aminoglycoside regimen group [AGs (60.5 dB) vs BDQ (44 dB);p < 0.001]. The double difference was significant, with a greater increase in hearing loss in the AGs group (diff-in-diff 18.3;p < 0.001). After adjustment for age and serum albumin, the group receiving the AG-based regimen had a 2-point greater worsening than those with bedaquiline at the sixth month (diff-in-diff 19.8;p Conclusion: Hearing loss is frequent with both treatment regimens, but more marked with the Aminoglycoside-based regimen. Thus, bedaquiline should also benefit for audiometric monitoring in future MDR-TB patients.展开更多
Background and Prupose: Antibiotic resistance is a major global health concern. In addition to the existing data on the prevalence of bacterial resistance to antibiotics, there are patchy data on bacterial resistance ...Background and Prupose: Antibiotic resistance is a major global health concern. In addition to the existing data on the prevalence of bacterial resistance to antibiotics, there are patchy data on bacterial resistance to aminoglycosides in Burkina Faso. In this study, we determined the prevalence of aminoglycoside resistance genes in E. coli, including aac(3)-IIc, aac(6)-Ib and armA in Ouagadougou, and determined which antibiotics in this class are most affected by resistance. Material and Methods: This study was conducted on 216 E. coli strains collected from the biomedical analysis laboratories of Saint Camille and Schiphra hospitals. E. coli strains were isolated from pus and urine samples collected between September 2018 and January 2019. Antibiotic susceptibility testing was performed using aminoglycosides, β-lactams, fluoroquinolones, and sulfonamides. Aminoglycoside resistance genes were detected in strains with at least one aminoglycoside resistance gene using conventional/multiplex PCR. Results: Aminoglycoside resistance was observed in 46.8% (101/216) of strains. The resistance rates were respectively 45.37% for Tobramycin, 32.40% for Gentamicin, 14.81% for Kanamycin, 2.31% for Netilmicin, 1.84% for Neomycin, and 0.46% for Amikacin. PCR showed that 86 strains (85.15%) possessed the aac(3)-IIc gene, 71 strains or 70.30%) possessed the aac(6’)-Ib gene, and nine strains (8.91%) possessed the armA gene. Conclusion: Aminoglycoside resistance in pathogenic E. coli strains is mainly due to the presence of the aac(3’)-IIc and aac(6’)-Ib genes. The presence of armA was first reported in Burkina Faso. Netilmicin, Neomycin and Amikacin are good therapeutic options for treating urinary tract and pus-forming infections.展开更多
Background: Aminoglycosides are used as empirical antibiotic treatment of intraabdominal infections which are caused by Gram negative bacteria and for which the treatment of choice is surgery. Aminoglycosides maintain...Background: Aminoglycosides are used as empirical antibiotic treatment of intraabdominal infections which are caused by Gram negative bacteria and for which the treatment of choice is surgery. Aminoglycosides maintain good efficacy against these bacteria and reduce the need for prescribing fluoroquinolone, cephalosporin and carbapenem antibiotics which contribute to the development of resistant bacterial strains. In recent years, several clinical trials and international guidelines have advised against the use of aminoglycosides owing largely to doubts about their effectiveness and to the concern for their known nephrotoxicity and ototoxicity. Aim: In our study, we aimed to prove whether aminoglycosides are appropriate agents in the treatment of acute appendicitis. Methods: Retrospectively, patients with acute appendicitis we included in the trial. Demographic characteristics, comorbidities, clinical signs and symptoms, the type of antibiotic and surgical treatment were analyzed. The effect of independent variables on the occurrence of complications was calculated using Student’s T-test and Fisher’s precise test. The effect of aminoglycosides on the loss of kidney function was determined by means of a linear regression method. Results: 300 patients proved acute appendicitis were included in the study. Univariate statistical analysis showed that the risk factors for postoperative complications in treating acute appendicitis were: age over 76 years (p Conclusion: Aminoglycoside antibiotics are a safe and effective treatment of acute appendicitis;our not published data are positive of AGs use in acute cholecystitis and left colon diverticulitis which requires surgery. If used for a limited time period, they do not increase the risk for kidney injury and remain a stable low level of all over complications.展开更多
To explore whether the metabolic state reprogramming approach may be used to explore previously unknown metabolic pathways that contribute to antibiotic resistance,especially those that have been neglected in previous...To explore whether the metabolic state reprogramming approach may be used to explore previously unknown metabolic pathways that contribute to antibiotic resistance,especially those that have been neglected in previous studies,pyruvate reprogramming was performed to reverse the resistance of multidrug-resistant Edwardsiella tarda.Surprisingly,we identified a pyruvate-regulated glutathione system that occurs by boosting glycine,serine,and threonine metabolism.Moreover,cysteine and methionine metabolism played a key role in this reversal.This process involved pyruvate-depressed glutathione and pyruvate-promoted glutathione oxidation,which was attributed to the elevated glutathione peroxidase and depressed glutathione reductase that was inhibited by glycine.This regulation inhibited reactive oxygen species(ROS)degradation and thereby elevated ROS to eliminate E.tarda.Loss of metB,gpx,and gor of the metabolic pathways increased and decreased resistance,respectively,both in vitro and in vivo,thereby supporting the hypothesis of a pyruvate–cysteine–glutathione system/glycine–ROS metabolic pathway.The role of this metabolic pathway in drug resistance and reprogramming reversal was demonstrated in laboratory-evolved gentamicin-resistant E.tarda and other clinically isolated multidrug-and carbapenem-resistant pathogens.Thus,we reveal a less studied antibiotic resistance metabolic pathway along with the mechanisms involved in its reversal.展开更多
Aminoglycosides are concentration-dependent antibiotics exerting a bactericidal effect when concentrations at the site of infection are equal to or greater than 5 times the minimum inhibitory concentrations(MIC).When ...Aminoglycosides are concentration-dependent antibiotics exerting a bactericidal effect when concentrations at the site of infection are equal to or greater than 5 times the minimum inhibitory concentrations(MIC).When administered intravenously,they exhibit poor lung penetration and high systemic renal and ototoxicity,imposing to restrict their administration to 5 days.Experimental studies conducted in anesthetized and mechanically ventilated sheep and pigs provide evidence that high doses of nebulized aminoglycosides induce a rapid and potent bacterial killing in the infected lung parenchyma.They also confirm that the alveolar-capillary membrane,either normal or injured by the infectious process,restricts the penetration of intravenous aminoglycosides in the infected lung parenchyma,precluding a bactericidal effect at the site of infection.However,injury of the alveolar-capillary membrane promotes the systemic diffusion of nebulized aminoglycosides.Based on experimental data obtained in animals with inoculation pneumonia,it challenges the classical belief that nebulization protects against systemic toxicity.Loss of lung aeration decreases the lung penetration of nebulized aminoglycosides.Nevertheless,lung tissue concentrations measured in non-aerated lung regions with severe and extended pneumonia are most often greater than 5 times the MICs,resulting in a bactericidal effect followed by a progressive pulmonary reaeration.It is likely that the penetration into the consolidated lung,results from the bronchial diffusion of nebulized aminoglycosides toward adjacent non-aerated infected alveolar spaces and their penetration into mechanical ventilation-induced intraparenchymal pseudocysts and distended bronchioles.In animals receiving nebulized aminoglycosides,epithelial lining fluid concentrations grossly overestimate lung interstitial fluid concentrations because of the bronchial contamination of the distal tip of the bronchoscope during the bronchoalveolar procedures.Lung microdialysis is the only technique able to accurately assess lung pharmacokinetics in animals with inoculation pneumonia treated by nebulized aminoglycosides.In 2024,the European Investigators Network for Nebulized Antibiotics in Ventilator-associated Pneumonia(ENAVAP)called for the creation of an international research network for Lung Microdialysis applied to Nebulized Antibiotics(LUMINA)to promote multicentered,experimental,randomized,and controlled studies addressing lung pharmacokinetics of intravenous vs.nebulized antibiotics,using different dosing and ventilator settings.展开更多
Aminoglycosides(AGs)are a class of antibiotics with a broad spectrum of activity.However,their use is limited by safety concerns associated with nephrotoxicity and ototoxicity,as well as drug resistance.To address the...Aminoglycosides(AGs)are a class of antibiotics with a broad spectrum of activity.However,their use is limited by safety concerns associated with nephrotoxicity and ototoxicity,as well as drug resistance.To address these issues,semi-synthetic approaches for modifying natural AGs have generated new generations of AGs,however,with limited types of modification due to significant challenges in synthesis.This study explores a novel approach that harness the bacterial biosynthetic machinery of gentamicins and kanamycins to create hybrid AGs.This was achieved by glycodiversification of gentamicins via swapping the glycosyltransferase(GT)in their producer with the GT from kanamycins biosynthetic pathway and resulted in the creation of a series of novel AGs,therefore referred to as genkamicins(GKs).The manipulation of the hybrid biosynthetic pathway enabled the targeted accumulation of different GK species and the isolation and characterization of six GK components.These compounds display retained antimicrobial activity against a panel of World Health Organization(WHO)critical priority pathogens,and GK-C2a,in particular,demonstrates low ototoxicity compared to clinical drugs in zebrafish embryos.This study provides a new strategy for diversifying the structure of AGs and a potential avenue for developing less toxic AG drugs to combat infectious diseases.展开更多
In general,the initiation or closure of antibiotic biosynthesis is determined by regulatory proteins,but most of their mechanisms of action remain unknown.The 2-deoxystreptamine-containing aminoglycosides(2-DOS AGs)fo...In general,the initiation or closure of antibiotic biosynthesis is determined by regulatory proteins,but most of their mechanisms of action remain unknown.The 2-deoxystreptamine-containing aminoglycosides(2-DOS AGs)form a unique category among antibiotics.Genomic analysis revealed that a group of hypothetical regulatory genes represented by neo I are widely distributed in the biosynthetic gene clusters(BGCs)of natural products from Streptomyces species,including several 2-DOS AGs.Only limited knowledge is available for the roles of Neo Itype regulators although neomycin and some of the related AGs have been developed as therapeutic drugs for decades.This study focuses on the functional determination of neo I and its homologues situated in the BGCs of six AGs.We found that the yield of neomycin in neo I disruption mutant(Δneo I)increased by 50%compared to the wild-type(WT)strain((420.6±44.1)mg L^(-1)),while it was partially restored by the complementation of neo I,demonstrating that Neo I acted as a repressor in neomycin biosynthesis.Further electrophoretic mobility shift assays(EMSAs)and DNase I footprinting assays indicated that Neo I could specifically bind to the promoter region between neo E and neo I with conserved nucleotides(5'-CVHYMRCHDKAGYGGACR-3'),as determined by site-directed mutagenesis.Interestingly,cross-bindings of the Neo I homologues from the six different BGCs to their corresponding DNA targets were manifested,and the five exogenous Neo I homologues could complement Neo I function of repressing neomycin biosynthesis.Our results suggested that Neo I-type regulators represent widespread and conservative regulatory characteristics in the biosynthesis of 2-DOS AGs,which would be significant for optimizing the biosynthetic pathways of valuable commercialized aminoglycoside antibiotics.展开更多
基金National Basic Research Program(973 Program, Grant No.2004CB518904)the State New Drug Innovation (Grant No.2009ZX09301-010,2009ZX09103 -044).
文摘A novel method to prepare guanidine substituted aminoglycoside derivatives was developed.Free guanidine reacted with Cbz-protected aminoglycosides to produce guanidinylcarbonyl substituted derivatives.A methoxycarbonyl-protected intermediate was isolated,and the mechanism of guanidinylcarbonyl modification was proposed.With this method,six per- or part-guanidylcarbonyl substituted aminoglycosides were successfully obtained in good yields.Their in vitro antibacterial activities were essayed.
基金National Basic Research Program(973 Program Grant No.2004CB518904)
文摘A series of urea-linked hydroxyl-alkylamine derivatives of aminoglycosides have been obtained by modification of neamine （1）, kanamycin （2） and ribostamycin （3） at 1, 6＇ and 3 N-sites, respectively, through selective cyclization and nucleophilic ring-opening of cyclic carbamates. All the products showed no noticeable activity in the antibiotic test in vitro. The result suggests that the urea-linked hydroxyl-alkylamine derivatives of aminoglycosides may not be suitable structures for the enhancement of antibiotic activity.
基金supported by the project from National Basic Research Priorities Program of China (2014CB541702)National Natural Science Foundation of China (31671305)
文摘Aminoglycosides(Am An) are widely used for their great efficiency against gram-negative bacterial infections. However, they can also induce ototoxic hearing loss, which has affected millions of people around the world. As previously reported, individuals bearing mitochondrial DNA mutations in the 12 S rRNA gene, such as m.1555A>G and m.1494C>T, are more prone to Am An-induced ototoxicity. These mutations cause human mitochondrial ribosomes to more closely resemble bacterial ribosomes and enable a stronger aminoglycoside interaction. Consequently,exposure to Am An can induce or worsen hearing loss in these individuals. Furthermore, a wide range of severity and penetrance of hearing loss was observed among families carrying these mutations. Studies have revealed that these mitochondria mutations are the primary molecular mechanism of genetic susceptibility to Am An ototoxicity, though nuclear modifier genes and mitochondrial haplotypes are known to modulate the phenotypic manifestation.
文摘Objective:To explore the antiviral activity of antibiotic compounds,mainly aminoglycosides and tetracyclines against Japanese encephalitis virus(JEV) induced infection in vitro.Methods:Antiviral activity were evaluated against JEV using cytopathic effect inhibition assay,virus yield reduction assay,caspase 3 level,extracellular viral detection by antigen capture ELISA and viral RNA levels.Roults:JEV induced cytopathic effect along with reduction of viral progeny plaque formation indicated antiviral potential of the compounds suggesting that antibiotics had broad spectrum activity.Doxycycline and kanamycin administration in dose dependent manner declined viral RNA replication.Conclusions:The present study shows kanamycin and doxycyclinc can affect virion structure and alter replication causing inhibition of JEV induced pathogenesis in vitro.
基金funded by National Natural Science Foundation of China (No. 81000754)a grant from the Key Laboratory for Laboratory Medicine of Jiangsu Province of China (No. XK201114)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Shigellosis causes diarrheal disease in humans in both developed and developing countries, and multi-drug resistance in Shigella is an emerging problem. Understanding changing resistance patterns is important in determining appropriate antibiotic treatments. This meta-analysis systematically evaluated aminoglycoside resistance in Shigella. A systematic review was constructed based on MEDLINE and EMBASE databases. Randomeffect models or fixed-effect models were used based on P value considering the possibility of heterogeneity between studies for meta-analysis. Data manipulation and statistical analyses were performed using software STATA 11.0. By means of meta-analysis, we found a lower resistance to three kinds of aminoglycosides in the Europe-America areas during the 12 year study period than that of the Asia-Africa areas. Kanamycin resistance was observed to be the most common drug resistance among Shigella isolates with a prevalence of 6.88% （95%CI： 6.36%-7.43%）. Comparison of data from Europe-America and Asia-Africa areas revealed that Shigella flexneri resistance was greater than the resistance calculated for Shigella sonnei. Importantly, Shigella sonnei has played a significant role in aminoglycoside-resistance in recent years. Similarly, data showed that resistance to these drugs in children was higher than the corresponding data of adults. In conclusion, aminoglycoside-resistant Shigella is not an unusual phenomenon worldwide. Distribution in Shigella resistance differs sharply based on geographic areas, periods of time and subtypes. The results from the present study highlight the need for con- tinuous surveillance of resistance and control of antibiotic usage.
文摘The mitochondrial 12S rRNA has been shown to be the hot spot for mutations associated with both aminoglycoside-induced and non-syndromic hearing loss. Of all the mutations, the homoplasmic A1555G and C1494T mutations at a highly conserved decoding region in the 12S rRNA have been associated with aminoglycoside-induced and non-syndromic hearing loss in many families worldwide. The A1555G or C1494T mutation is expected to form novel 1494C-G1555 or 1494U-A1555 base-pair at the highly conserved A-site of 12S rRNA. These transitions make the secondary structure of this RNA more closely resemble the corresponding region of bacterial 16S rRNA. Thus, the new U-A or G-C pair in 12S rRNA created by the C1494T or A1555G transition facilitates the binding of aminoglycosides, thereby accounting for the fact that the exposure to aminoglycosides can induce or worsen hearing loss in individuals carrying these mutations. Furthermore, the growth defect and impairment of mitochondrial translation were observed in cell lines carrying the A1555G or C1494T mutation in the presence of high concentration of aminoglycosides. In addition, nuclear modifier genes and mitochondrial haplotypes modulate the phenotypic manifestation of the A1555G and C1494T mutations. These observations provide the direct genetic and biochemical evidences that the A1555G or C1494T mutation is a pathogenic mtDNA mutation associated with aminoglycoside-induced and nonsyndromic hearing loss. Therefore, these data have been providing valuable information and technology to predict which individuals are at risk for ototoxicity, to improve the safety of aminoglycoside antibiotic therapy, and eventually to decrease the incidence of deafness.
基金supported by grants from the National Basic Research Program of China(973Program)(2012CB9679002012CB967901)+3 种基金Beijing Natural Science Foundation(5122040)supported by grants from the China Postdoctoral Science Foundation(20100377920100470103)the National Natural Science Foundation of China(NSFC)(31040 038)
文摘Objective To study presynaptic alternations of cochlear ribbons arising from aminoglycoside ototoxic stimuli in C57BL/6J mice. Methods Animals were injected with low dose gentamicin (100 mg/kg/day) for 14 days, From the 14th to 28th days, the mice were maintained free of gentamicin treatment. Immunohisto-chemistry labeling was employed to trace RIBEYE, a major presynaptic componment of ribbon synapses. RIBEYE/CtBP2 expression levels were assessed and compared with hearing threshold shifts. Auditory func-tion was assessed by auditory brainstem responses. The stereocilia of outer hair cells (OHCs) and IHCs was examined by scanning electron microscopy (SEM). Results Hearing thresholds were elevated with peak hearing loss observed on the 7th day after gentamicin exposure, followed by improvement after the 7th day. RIBEYE/CtBP2 expression directly correlated with observed hearing threshold shifts. Strikingly, we did not see any obvious changes in stereocilia in both OHCs and IHCs until the 28th day. Mild changes in stereocil-ia were only observed in OHCs on the 28th day. Conclusions These findings indicate that presynapse co-chlear ribbons, rather than stereocilia, may be sensitive to aminoglycoside ototoxic exposure in mice cochle-ae. A pattern of RIBEYE/CtBP2 expression changes seems to parallel hearing threshold shifts and suggests presynaptic response properties to lower dosage of aminoglycoside ototoxic stimuli.
文摘To investigate the underlying mechanism of the exacerbation of myasthenia gravis by aminoglycoside antibiotics. C57/BL6 mice were immunized with acetylcholine receptor (AChR), extracted from electric organ of Narcine timilei according to Xu Haopeng's methods, in complete Fruend's adjuvant (CFA) to establish experimental autoimmune myasthenia gravis (EAMG). EAMG mice were divided randomly into 5 groups: MG group, NS group and three antibiotics groups. The clinical symptom scores of mice were evaluated on d7 after the last immunization and d14 of antibiotics treatment. Repetitive nerve stimulation (RNS) was performed and the levels of anti-AChR antibody (AChR-Ab) were tested at the same time. The mean clinical symptom grades of gentamycin group (1.312, 2.067), amikacin group (1.111, 1.889) and etimicin group (1.263, 1.632) were significantly higher than those of MG group (1.000, 1.200) (P<0.05). The positive rates of RNS of three antibiotics groups were 69.23 %, 58.82 % and 63.16 % respectively, which were significantly higher than those of MG group and NS group (40.00 %, 40.00 %, P<0.05). The AChR-Ab level in serum and the expression of AChR on neuromuscular junction (NMJ) of mice in three antibiotics groups were also higher than those of MG group. Our results indicated that aminoglycoside antibiotics could aggravate the symptom of myasthenia gravis. The exacerbation of myasthenia gravis by these antibiotics probably involves competitively restraining the release of acetylcholine from presynaptic membrane, impairing the depolarization of postsynaptic membrane, depressing the irritability of myocyte membrane around the end-plate membrane and consequently leading to the blockade of neuromuscular junction.
文摘The Pharmacokinetics informations of aminoglycosides, their monograph and clinical Pharmacokinetics parameters are reported in this review. The Aminoglycosides are highly polarity and in reserve for serious infections caused by aerobic gram negative bacteria and some gram positive bacteria but their toxicity are major limitations in clinical use.
文摘Aminoglycosides are a family of antibiotics with important applications in veterinary medicine. Their ionic character, the similarity structures and the high polarity due to the presence of two or more amino and hydroxyl groups cause a difficulty in separation and make these compounds poorly retained on the reversed phase column. An analytical method for the separation and detection of 12 aminoglycosides has been optimized using two kinds of chromatographic conditions (HILIC, Ion pairing). In Hydrophilic Interaction, ZIC_HILIC column was used, by which the following parameters for the mobile phase were evaluated: concentration of ammonium acetate buffer, percentage of formic acid and effect of acid type. The maximum and adequate concentration of ammonium acetate for the majority of analytes was set to 30 mM. The percentage 0.1% of formic acid increases the response for the majority of analytes. On the other side, the use of 0.1% of trifluoroacetic acid improves the response when compared with the response obtained with 0.1% of formic acid except for Spectinomycin Dihydrostreptomycin and Streptomycin. For ion pairing chromatography, the concentration of pentafluoropropionic acid was tested and the greatest value appeared to be 9.2 mM. Therefore, the comparison between the two separation methods shows that the response area of the majority of analytes tested increases when using the ion pair mode. Also, the high value of S/N and the lower detection limit (5 - 15 μg m·L﹣1 for most aminoglycosides studied make the ion pairing method more preferable than HILIC interaction.
基金supported by the National Natural Science Foundation of China(No.21877006).
文摘For the purpose of seeking new antibiotics,researchers usually modify the already-existing ones.However,this strategy has been extensively used and is close to its limits,especially in the case of aminoglycosides,and it is difficult to find a proper aminoglycoside antibiotic for novel modification.In this paper,we reported the design,synthesis,and evaluation of a series of 5-epi-neamine derivatives based on the structural information of bacterial 16S RNA A-site binding with aminoglycosides.Bioassay results showed that our design strategy was feasible.Our study offers a new way to search for structurally novel aminoglycosides.Meanwhile,our study provides valuable structure-activity relationship information,which will lead to better understanding and exploitation of the drug target,and improved development of new aminoglycoside antibiotics.
基金Foundation items： National Basic Research Program （973 Program, Grant No. 2004CB518904） and the State New Drug Innovation Grant No. 2009ZX09301-010, 2009ZX09103-044）.
文摘A novel method to prepare guanidine substituted aminoglycoside derivatives was developed. Free guanidine reacted with Cbz-protected aminoglyeosides to produce guanidinylearbonyl substituted derivatives. A methoxycarbonyl-protected intermediate was isolated, and the mechanism of guanidinylcarbonyl modification was proposed. With this method, six per- or part- guanidylcarbonyl substituted aminoglycosides were successfully obtained in good yields. Their in vitro antibacterial activities were essayed.
文摘Aminoglycosides are one of the categories of antibiotics most frequently used in treating several cattle diseases at the Central Cattle Breeding and Dairy Farm (CCBDF), Savar,Dhaka,Bangladesh. Untreated veterinary clinical healthcare waste (VCHW) of diseased cattle at CCBDF which directly disposed to surrounding may contribute to the antibiotic resistant bacteria pollution (ARB) pollution. The investigation analyses the role of VCHW of CCBDF in spreading ARB. Here we studied:1) veterinary clinical data and antibiotics treatment history;2) total and resistant bacteria counts in fecal samples of healthy and diseased cattles as well as VCHW of CCBDF;and 3) finally, data analysis to estimate the burden of VCHW of CCBDF in the pollution of environment with aminoglycoside antibiotics resistant bacteria. The results conclusively demonstrate the spread of 3 different aminoglycoside antibiotics, namely genta- mycin, kanamycin and streptomycin resistant bacte- ria in the surrounding environment alarmingly with high significant value (p < 0.01 - 0.05). This study re- veals the risks to the cattle as well as public health posed by the random VCHW disposal at the CCBDF, Bangladesh.
文摘Context: Multidrug-resistant tuberculosis (MDR-TB) remains a major public health problem in developing countries such as the Democratic Republic of Congo (DRC), which continues to face the emergence of MDR-TB cases. Because of the ototoxic effects of AGs, the World Health Organization (WHO) has recommended the introduction of the bedaquiline regimen. However, very few data are available regarding the susceptibility of bedaquiline to induce hearing loss, hence the present study set out to compare the AG-based regimen and the bedaquiline-based regimen in the occurrence of hearing loss in MDR-TB patients. Methods: This is a prospective multicenter cohort study that included 335 MDR-TB patients, performed in Kinshasa (DRC) during the period from January 2020 to January 2021. Sociodemographic, clinical, biological and audiometric data were analyzed using Stata 17. Repeated-measures analysis of variance was used to compare changes in the degree of hearing loss over time between the two groups of patients on AG and bedaquiline regimens. The double-difference method was estimated using regression with fixed-effects. A p value < 0.05 was considered the threshold for statistical significance. Results: The degree of hearing loss was similar between the two groups at the first month [AGs (28 dB) vs BDQ (30 dB);p = 0.298]. At six months, the mean degree of hearing loss was significantly greater in the aminoglycoside regimen group [AGs (60.5 dB) vs BDQ (44 dB);p < 0.001]. The double difference was significant, with a greater increase in hearing loss in the AGs group (diff-in-diff 18.3;p < 0.001). After adjustment for age and serum albumin, the group receiving the AG-based regimen had a 2-point greater worsening than those with bedaquiline at the sixth month (diff-in-diff 19.8;p Conclusion: Hearing loss is frequent with both treatment regimens, but more marked with the Aminoglycoside-based regimen. Thus, bedaquiline should also benefit for audiometric monitoring in future MDR-TB patients.
文摘Background and Prupose: Antibiotic resistance is a major global health concern. In addition to the existing data on the prevalence of bacterial resistance to antibiotics, there are patchy data on bacterial resistance to aminoglycosides in Burkina Faso. In this study, we determined the prevalence of aminoglycoside resistance genes in E. coli, including aac(3)-IIc, aac(6)-Ib and armA in Ouagadougou, and determined which antibiotics in this class are most affected by resistance. Material and Methods: This study was conducted on 216 E. coli strains collected from the biomedical analysis laboratories of Saint Camille and Schiphra hospitals. E. coli strains were isolated from pus and urine samples collected between September 2018 and January 2019. Antibiotic susceptibility testing was performed using aminoglycosides, β-lactams, fluoroquinolones, and sulfonamides. Aminoglycoside resistance genes were detected in strains with at least one aminoglycoside resistance gene using conventional/multiplex PCR. Results: Aminoglycoside resistance was observed in 46.8% (101/216) of strains. The resistance rates were respectively 45.37% for Tobramycin, 32.40% for Gentamicin, 14.81% for Kanamycin, 2.31% for Netilmicin, 1.84% for Neomycin, and 0.46% for Amikacin. PCR showed that 86 strains (85.15%) possessed the aac(3)-IIc gene, 71 strains or 70.30%) possessed the aac(6’)-Ib gene, and nine strains (8.91%) possessed the armA gene. Conclusion: Aminoglycoside resistance in pathogenic E. coli strains is mainly due to the presence of the aac(3’)-IIc and aac(6’)-Ib genes. The presence of armA was first reported in Burkina Faso. Netilmicin, Neomycin and Amikacin are good therapeutic options for treating urinary tract and pus-forming infections.
文摘Background: Aminoglycosides are used as empirical antibiotic treatment of intraabdominal infections which are caused by Gram negative bacteria and for which the treatment of choice is surgery. Aminoglycosides maintain good efficacy against these bacteria and reduce the need for prescribing fluoroquinolone, cephalosporin and carbapenem antibiotics which contribute to the development of resistant bacterial strains. In recent years, several clinical trials and international guidelines have advised against the use of aminoglycosides owing largely to doubts about their effectiveness and to the concern for their known nephrotoxicity and ototoxicity. Aim: In our study, we aimed to prove whether aminoglycosides are appropriate agents in the treatment of acute appendicitis. Methods: Retrospectively, patients with acute appendicitis we included in the trial. Demographic characteristics, comorbidities, clinical signs and symptoms, the type of antibiotic and surgical treatment were analyzed. The effect of independent variables on the occurrence of complications was calculated using Student’s T-test and Fisher’s precise test. The effect of aminoglycosides on the loss of kidney function was determined by means of a linear regression method. Results: 300 patients proved acute appendicitis were included in the study. Univariate statistical analysis showed that the risk factors for postoperative complications in treating acute appendicitis were: age over 76 years (p Conclusion: Aminoglycoside antibiotics are a safe and effective treatment of acute appendicitis;our not published data are positive of AGs use in acute cholecystitis and left colon diverticulitis which requires surgery. If used for a limited time period, they do not increase the risk for kidney injury and remain a stable low level of all over complications.
基金supported by the National Key Research and Development Program of China(grant number 2023YFD1800104)National Natural Science Foundation of China(grant numbers 32273177 and 42276125)+2 种基金Fundamental Research Funds for the Central Universities,Sun Yat-sen University(grant number 24lgzy004)Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(grant number 311020006)Science and Technology Planning Project of Guangdong Province(no.2023B1212060028).
文摘To explore whether the metabolic state reprogramming approach may be used to explore previously unknown metabolic pathways that contribute to antibiotic resistance,especially those that have been neglected in previous studies,pyruvate reprogramming was performed to reverse the resistance of multidrug-resistant Edwardsiella tarda.Surprisingly,we identified a pyruvate-regulated glutathione system that occurs by boosting glycine,serine,and threonine metabolism.Moreover,cysteine and methionine metabolism played a key role in this reversal.This process involved pyruvate-depressed glutathione and pyruvate-promoted glutathione oxidation,which was attributed to the elevated glutathione peroxidase and depressed glutathione reductase that was inhibited by glycine.This regulation inhibited reactive oxygen species(ROS)degradation and thereby elevated ROS to eliminate E.tarda.Loss of metB,gpx,and gor of the metabolic pathways increased and decreased resistance,respectively,both in vitro and in vivo,thereby supporting the hypothesis of a pyruvate–cysteine–glutathione system/glycine–ROS metabolic pathway.The role of this metabolic pathway in drug resistance and reprogramming reversal was demonstrated in laboratory-evolved gentamicin-resistant E.tarda and other clinically isolated multidrug-and carbapenem-resistant pathogens.Thus,we reveal a less studied antibiotic resistance metabolic pathway along with the mechanisms involved in its reversal.
文摘Aminoglycosides are concentration-dependent antibiotics exerting a bactericidal effect when concentrations at the site of infection are equal to or greater than 5 times the minimum inhibitory concentrations(MIC).When administered intravenously,they exhibit poor lung penetration and high systemic renal and ototoxicity,imposing to restrict their administration to 5 days.Experimental studies conducted in anesthetized and mechanically ventilated sheep and pigs provide evidence that high doses of nebulized aminoglycosides induce a rapid and potent bacterial killing in the infected lung parenchyma.They also confirm that the alveolar-capillary membrane,either normal or injured by the infectious process,restricts the penetration of intravenous aminoglycosides in the infected lung parenchyma,precluding a bactericidal effect at the site of infection.However,injury of the alveolar-capillary membrane promotes the systemic diffusion of nebulized aminoglycosides.Based on experimental data obtained in animals with inoculation pneumonia,it challenges the classical belief that nebulization protects against systemic toxicity.Loss of lung aeration decreases the lung penetration of nebulized aminoglycosides.Nevertheless,lung tissue concentrations measured in non-aerated lung regions with severe and extended pneumonia are most often greater than 5 times the MICs,resulting in a bactericidal effect followed by a progressive pulmonary reaeration.It is likely that the penetration into the consolidated lung,results from the bronchial diffusion of nebulized aminoglycosides toward adjacent non-aerated infected alveolar spaces and their penetration into mechanical ventilation-induced intraparenchymal pseudocysts and distended bronchioles.In animals receiving nebulized aminoglycosides,epithelial lining fluid concentrations grossly overestimate lung interstitial fluid concentrations because of the bronchial contamination of the distal tip of the bronchoscope during the bronchoalveolar procedures.Lung microdialysis is the only technique able to accurately assess lung pharmacokinetics in animals with inoculation pneumonia treated by nebulized aminoglycosides.In 2024,the European Investigators Network for Nebulized Antibiotics in Ventilator-associated Pneumonia(ENAVAP)called for the creation of an international research network for Lung Microdialysis applied to Nebulized Antibiotics(LUMINA)to promote multicentered,experimental,randomized,and controlled studies addressing lung pharmacokinetics of intravenous vs.nebulized antibiotics,using different dosing and ventilator settings.
基金the National Key R&D Program of China(2018YFA0903200)the Funds for International Cooperation and Exchange of the National Natural Science Foundation of China(31920103001).
文摘Aminoglycosides(AGs)are a class of antibiotics with a broad spectrum of activity.However,their use is limited by safety concerns associated with nephrotoxicity and ototoxicity,as well as drug resistance.To address these issues,semi-synthetic approaches for modifying natural AGs have generated new generations of AGs,however,with limited types of modification due to significant challenges in synthesis.This study explores a novel approach that harness the bacterial biosynthetic machinery of gentamicins and kanamycins to create hybrid AGs.This was achieved by glycodiversification of gentamicins via swapping the glycosyltransferase(GT)in their producer with the GT from kanamycins biosynthetic pathway and resulted in the creation of a series of novel AGs,therefore referred to as genkamicins(GKs).The manipulation of the hybrid biosynthetic pathway enabled the targeted accumulation of different GK species and the isolation and characterization of six GK components.These compounds display retained antimicrobial activity against a panel of World Health Organization(WHO)critical priority pathogens,and GK-C2a,in particular,demonstrates low ototoxicity compared to clinical drugs in zebrafish embryos.This study provides a new strategy for diversifying the structure of AGs and a potential avenue for developing less toxic AG drugs to combat infectious diseases.
基金supported by the National Natural Science Foundation of China (32170043,82173720)the National Key Research and Development Program of China (2020YFA0907800)。
文摘In general,the initiation or closure of antibiotic biosynthesis is determined by regulatory proteins,but most of their mechanisms of action remain unknown.The 2-deoxystreptamine-containing aminoglycosides(2-DOS AGs)form a unique category among antibiotics.Genomic analysis revealed that a group of hypothetical regulatory genes represented by neo I are widely distributed in the biosynthetic gene clusters(BGCs)of natural products from Streptomyces species,including several 2-DOS AGs.Only limited knowledge is available for the roles of Neo Itype regulators although neomycin and some of the related AGs have been developed as therapeutic drugs for decades.This study focuses on the functional determination of neo I and its homologues situated in the BGCs of six AGs.We found that the yield of neomycin in neo I disruption mutant(Δneo I)increased by 50%compared to the wild-type(WT)strain((420.6±44.1)mg L^(-1)),while it was partially restored by the complementation of neo I,demonstrating that Neo I acted as a repressor in neomycin biosynthesis.Further electrophoretic mobility shift assays(EMSAs)and DNase I footprinting assays indicated that Neo I could specifically bind to the promoter region between neo E and neo I with conserved nucleotides(5'-CVHYMRCHDKAGYGGACR-3'),as determined by site-directed mutagenesis.Interestingly,cross-bindings of the Neo I homologues from the six different BGCs to their corresponding DNA targets were manifested,and the five exogenous Neo I homologues could complement Neo I function of repressing neomycin biosynthesis.Our results suggested that Neo I-type regulators represent widespread and conservative regulatory characteristics in the biosynthesis of 2-DOS AGs,which would be significant for optimizing the biosynthetic pathways of valuable commercialized aminoglycoside antibiotics.
