Derivative Of Gentamicin Research Articles

In-vitro Activity of Isepamicin against Gram-negative Bacteria in Comparison to Other Aminoglycosides Routinely used at a Teaching Hospital in Northern India.

Background Isepamicin is a 1-N-S-a-hydroxy-b-aminopropionyl derivative of gentamicin B and the spectrum of pathogenic microorganisms covered by it and its effectiveness is similar to that of amikacin except the action of aminoglycoside inhibitor enzymes is ineffectual on it. Material and Methods We performed a prospective study in the Bacteriology section of the Department of Microbiology at a 1,600-bedded hospital in Northern India from Jan 2022 to March 2022. Isepamicin was tested for susceptibility against gram-negative bacteria, identified by routine biochemicals and matrix-assisted-desorption/ionization -time of flight-mass spectrometry (MALDI-TOF-MS) assay. The antibiotic susceptibility testing for each of the isolates was performed by Kirby Bauer's disc diffusion method, according to the CLSI 2019 guidelines. Results The majority of isolates were obtained from blood samples (50, 39.1%). Among the non-inducible Enterobacteriaceae , Escherichia coli was least susceptible to amikacin (8/27, 29.63%) and most susceptible to isepamicin (18/27, 66.67%). Klebsiella pneumoniae followed the same pattern of susceptibility as E. coli and was least susceptible to Amikacin (20/46, 43.48%) and most susceptible to isepamicin (24/46, 52.17%). Enterobacter cloacae (6/7, 85.71%) was most susceptible to both amikacin and isepamicin, followed by 71.43% (5/7, 71.43%) susceptibility to gentamicin and tobramycin each. Enterobacter aerogenes was equally 53.33% (8/15) susceptible to all antibiotics. Pseudomonas aeruginosa was the most susceptible isolate to all antibiotics (18/21, 85.71%). Conclusion Isepamicin is a potential antimicrobial agent for treating an array of gram-negative bacteria-associated infections and shows better in vitro activity than older aminoglycoside agents.

Antifungal Activity of Gentamicin B1 Against Systemic Plant Mycoses.

Background: Gentamicin is a broad-spectrum aminoglycoside antibiotic produced by Micromonospora purpurea bacteria, effective against Gram-negative bacterial infections. Major fractions of the gentamicin complex (C1, C1a, C2, C2a) possess weak antifungal activity and one of the minor components (A, A1–A4, B, B1, X), gentamicin B1 was found to be a strong antifungal agent. Methods: This work uses in vitro and in vivo dilution methods to compare the antifusarial, antiaspergillic and anticryptococcal effects of gentamicin derivatives and structurally-related congeners. Results: The in vitro antifusarial activity of gentamicin B1 (minimum inhibitory concentration (MIC) 0.4 μg/mL) and structurally-related compounds (MIC 0.8–12.5 μg/mL) suggests that the purpuroseamine ring substituents are responsible for the specific antimycotic effect. The functional groups of the garoseamine and 2-deoxystreptamine rings of gentamicin derivatives are identical in gentamicin compounds and are unlikely to exert a significant antifungal effect. Among soil dermatophytes, Microsporum gypseum was more susceptible to gentamicin B1 (MIC 3.1 µg/mL) than Trichophyton gypseum (MIC 25 µg/mL). The in vitro antifungal effect of gentamicin B1 against plant pathogenic fungi was comparable to primary antifungal agents. Conclusion: Gentamicin is already in medical use. In vitro and preclinical in vivo synergisms of gentamicin B1 with amphotericin B suggest immediate clinical trials starting with subtoxic doses.

Molecular Modulation of a New Gentamicin Derivative Drug Using Quantum Calculation Methods

Molecular Modulation of a New Gentamicin Derivative Drug Using Quantum Calculation Methods

Synthesis and Characterizations of Dipeptide Derivative of Gentamicin

Abstract
 The target derivative are gentamicin linked with L-Val- L-Ala by an ester linkage. These were synthesized by esterification method, which included the reaction of -OH hydroxyl group on (carbon No.5) of gentamicin with the acid chloride of the corresponding dipeptide, The preparation of new derivative of gentamicin involved protected the primary & secondary amine groups of Gentamicin, by Ethylchloroformate (ECF) to give N-carbomethoxy Gentamicin which was used for further chemical synthesis involving the free hydroxyl groups.
 Then prepared dipeptide (L-Val- L-Ala) by conventional solution method in present DCC & HoBt then reacted with thionyl chloride to prepared acid chloride of dipeptides, then after, linked by ester linkage to N-protection gentamicin in present pyridine as base, finally deportation the amino group of synthesized compound by using TFAA in present anisole.
 The characterization of the titled compounds were performed utilizing FTIR spectroscopy, CHNS elemental analysis, and by measurements of their physical properties.

Assembly of a novel biosynthetic pathway for gentamicin B production in Micromonospora echinospora

BackgroundIsepamicin is a weakly toxic but highly active aminoglycoside antibiotic derivative of gentamicin B. Gentamicin B is a naturally occurring minor component isolated from Micromonospora echinospora. 2ʹ-NH2-containing gentamicin C complex is a dominant compound produced by wild-type M. echinospora; by contrast, 2ʹ-OH-containing gentamicin B is produced as a minor component. However, the biosynthetic pathway of gentamicin B remains unclear. Considering that gentamicin B shares a unique C2ʹ hydroxyl group with kanamycin A, we aimed to design a new biosynthetic pathway of gentamicin B by combining twelve steps of gentamicin biosynthesis and two steps of kanamycin biosynthesis.ResultsWe blocked the biosynthetic pathway of byproducts and generated a strain overproducing JI-20A, which was used as a precursor of gentamicin B biosynthesis, by disrupting genK and genP. The amount of JI-20A produced in M. echinospora ∆K∆P reached 911 μg/ml, which was 14-fold higher than that of M. echinospora ∆P. The enzymes KanJ and KanK necessary to convert 2ʹ-NH2 into 2ʹ-OH from the kanamycin biosynthetic pathway were heterologously expressed in M. echinospora ΔKΔP to transform JI-20A into gentamicin B. The strain with kanJK under PermE* could produce 80 μg/ml of gentamicin B, which was tenfold higher than that of the wild-type strain. To enhance gentamicin B production, we employed different promoters and gene integration combinations. When a PhrdB promoter was used and kanJ and kanK were integrated in the genome through gene replacement, gentamicin B was generated as the major product with a maximum yield of 880 μg/ml.ConclusionWe constructed a new biosynthetic pathway of high-level gentamicin B production; in this pathway, most byproducts were removed. This method also provided novel insights into the biosynthesis of secondary metabolites via the combinatorial biosynthesis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-015-0402-6) contains supplementary material, which is available to authorized users.

Sub-acute toxicity study of a new aminoglycoside etimicin sulphate in <i>swiss albino</i> mice

Etimicin sulfate, an ethylization derivative of gentamicin, is a new soluble wide-spectrum synthetic aminoglycoside drug. It has wide antibacterial spectrum with high effect and less cross resistance as compared to other aminoglycosides. In order to further explore its safety and tolerance, we have conducted a subactute toxicity study on swiss albino mice. Results from the present study have elucidated that treatment of etimicin sulfate exerts no significant signs of toxicity at any dose level used in the study. Physiological as well as hematological parameters were unaltered throughout the study. Biochemical examination and histopathology of all organs confirmed no significant alteration at any dose levels. The result of this study has suggested there was no obvious toxicity observed with the treatment of etimicin sulphate. It was found to be a safe alternative for various severe infections.

Gene inactivation study of gntE reveals its role in the first step of pseudotrisaccharide modifications in gentamicin biosynthesis

A gene inactivation study was performed on gntE, a member of the gentamicin biosynthetic gene cluster in Micromonospora echinospora. Computer-aided homology analysis predicts a methyltransferase-related cobalamin-binding domain and a radical S-adenosylmethionine domain in GntE. It is also found that there is no gntE homolog within other aminoglycoside biosynthetic gene clusters. Inactivation of gntE was achieved in both M. echinospora ATCC 15835 and a gentamicin high-producer GMC106. High-performance liquid chromatographic analysis, coupled with mass spectrometry, revealed that gntE mutants accumulated gentamicin A2 and its derivative with a methyl group installed on the glucoamine moiety. This result substantiated that GntE participates in the first step of pseudotrisaccharide modifications in gentamicin biosynthesis, though the catalytic nature of this unusual oxidoreductase/methyltransferase candidate is not resolved. The present gene inactivation study also demonstrates that targeted genetic engineering can be applied to produce specific gentamicin structures and potentially new gentamicin derivatives in M. echinospora.

N-[(2-Sulfo)-9-fluorenylmethoxycarbonyl](3)-gentamicin C(1) is a long-acting prodrug derivative.

Most low-molecular-weight drugs are short-lived species in the circulatory system, being rapidly eliminated by glomerular filtration in the kidney. However, binding to human serum albumin (HSA) can slow clearance and prolong lifetime profile in vivo. In this study, we have engineered a gentamicin derivative with affinity to albumin by linking three (2-sulfo)-9-fluorenylmethoxycarbonyl (FMS) to three amino groups of gentamicin C(1). FMS(3)-gentamicin associates with HSA with a K(a) value of (1.31 +/- 0.2) x 10(5) M(-1). It has less than 1% the antibacterial potency of native gentamicin. Upon incubation at pH 8.5 and 37 degrees C, the FMS moieties from FMS(3)-gentamicin undergo slow hydrolysis (t(1/2) = 8.0 +/- 0.2 h), leading to a linear regeneration of the antibacterial potency with a t(1/2) value of 11 +/- 0.7 h. FMS(3)-gentamicin is a long-lived species in the rat circulatory system. Following a single subcutaneous or intravenous administration, it maintains a prolonged pharmacokinetic profile with a peak and a "through" concentration of immuno/antibacterial active gentamicin exceeding 4-5 times the duration obtained by administered native gentamicin. To sum up, an approach aimed at elongating the lifetime of low-molecular-weight drugs in vivo has been examined here with gentamicin. Two to three FMS per mole of compound are to be introduced to obtain an albumin associating affinity of K(d) = 7.6-9.2 microM and, hence, to significantly extend the drug's lifetime in situ following administration. By use of this technology, the loss of pharmacological potency with derivatization is of no consequence, since FMS moieties are hydrolyzed and activity is generated at physiological conditions.

Inhibition of bacterial RNase P by aminoglycoside–arginine conjugates

The potential of RNAs and RNA–protein (RNP) complexes as drug targets is currently being explored in various investigations. For example, a hexa-arginine derivative of neomycin (NeoR) and a tri-arginine derivative of gentamicin (R3G) were recently shown to disrupt essential RNP interactions between the trans-activator protein (Tat) and the Tat-responsive RNA ( trans-activating region) in the human immunodeficiency virus (HIV) and also inhibit HIV replication in cell culture. Based on certain structural similarities, we postulated that NeoR and R3G might also be effective in disrupting RNP interactions and thereby inhibiting bacterial RNase P, an essential RNP complex involved in tRNA maturation. Our results indicate that indeed both NeoR and R3G inhibit RNase P activity from evolutionarily divergent pathogenic bacteria and do so more effectively than they inhibit partially purified human RNase P activity.

Aminoglycoside-arginine conjugates that bind TAR RNA: synthesis, characterization, and antiviral activity.

Regulation of HIV gene expression is crucially dependent on binding of the trans-activator protein, Tat, to the trans-activation response RNA element, TAR, found at the 5' end of all HIV-1 transcripts. Tat-TAR interaction is mediated by a short arginine-rich domain of the protein. Disruption of this interaction could, in theory, create a state of complete viral latency. A new class of small-molecule peptidomimetic TAR RNA binders, conjugates of aminoglycosides and arginine, was recently designed [Litovchick, A., Evdokimov, A. G., and Lapidot, A. (1999) FEBS Lett. 445, 73-79]. Two of these compounds, the tri-arginine derivative of gentamicin C (R3G) and the tetra-arginine derivative of kanamycin A (R4K), bind efficiently and specifically to TAR RNA. These compounds display negligible toxicity while being transported and accumulated in cell nuclei. Here we present a detailed synthesis and chemical characterization of the aminoglycoside-arginine conjugates R3G and R4K as well as GB4K, the tetra-gamma-guanidinobutyric derivative of kanamycin A. Their binding sites on TAR RNA were assigned by RNase A, uranyl nitrate, and lead acetate footprinting. The conjugates interact with TAR RNA in the widened major groove, formed by the UCU bulge and the neighboring base pairs of the upper stem portion of TAR, the binding site of Tat protein, and Tat-derived peptides (e.g., R52). Our results suggest an additional binding site of R4K and R3G compounds, in the lower stem-bulge region of TAR. The antiviral activity of the conjugates in cultured equine dermal fibroblasts infected with equine infectious anemia virus, used as a model system of HIV-infected cells, is also presented.

The efficacy of controlled antibiotic release for prevention of polyethyleneterephthalate- (Dacron-) related infection in cardiovascular surgery

Infection of prostheses containing polyethyleneterephthalate (Dacron) remains a dreaded complication in cardiovascular surgery despite perioperative antibiotic (AB) prophylaxis. Dacron, which is widely applied as a fabric for manufacturing vascular prostheses and also the sewing rings of artificial heart valves, remains a source for infection once implanted in the body. In order to increase the AB concentration in Dacron, an experimental study including topical application of the gentamicin derivative EMD 46/217 and fibrin sealant (F) as AB carrier was initiated. In-vitro pretreatment of Dacron with the gentamicin derivative and F was followed by constant AB release for three weeks. In a subsequent animal study, four Dacron rings with different pretreatments were implanted in the descending aorta of ten pigs after direct contamination with 10 8 Staph. aureus solution. One ring was pretreated with the AB/F compound, a second ring with the AB alone. Ring 3 (no pretreatment) and ring 4 (F alone) served as controls. After one week, the Dacron rings and their corresponding implantation sites were asserved for measurement of AB content and for culture. The AB content of AB/F rings was 24·99 ± 7·16 μg/g wet weight, while Dacron rings pretreated with the AB alone contained no measurable drug amounts, with the exception of one specimen (0.5 μg/g) (AB/F versus AB rings: P < 0·0005 The corresponding implantation sites to AB/F rings contained 1·07 ± 0·54 μg/g AB, whereas in only 2/10 implantation sites of AB rings were low AB levels found 0·05 and 02 μg/g (AB/F versus AB ring implantation sites: P < 0·0005 While all Dacron rings, which served as controls and 9/10 Dacron rings pretreated with antibiotic alone were infected, 5/10 AB/F rings remained sterile after culture (AB/F versus AB rings: P = 0·05). This finding correlated with the AB content in the Dacron rings. Therefore, pretreatment of Dacron with the AB/F compound results in bounding of sufficient amounts of AB for at least one week. This measure for controlled release ou antibiotics can serve as a prophylactic tool against perioperative infection related to implantation of Dacron in cardiovascular surgery.

Formation of a toxic metabolite from gentamicin by a hepatic cytosolic fraction

We have demonstrated recently that incubation of the aminoglycoside gentamicin with an hepatic post-mitochondrial fraction produces a compound toxic to sensory cells from the inner ear in short-term culture; in contrast, the parent aminoglycoside was non-toxic in vitro (Huang MY and Schacht J, Biochem Pharmacol 40: R11–R14, 1990). In the present study, we investigated the subcellular distribution of the enzymatic activity and the nature of the metabolite. Isolated outer hair cells from the guinea pig cochlea were used to assay for cytotoxicity. The enzyme(s) responsible for this novel reaction of aminoglycosides was exclusively localized to the cytosolic fraction of guinea pig liver. No activity was detected in nuclear, lysosomal/mitochondrial or microsomal preparations. Furthermore, the toxin-forming enzymatic activity was associated with the high molecular weight fraction of the cytosol and did not require low molecular weight components. Filtration of the toxin through molecular weight cut-off membranes showed a molecular size of approximately 500. This evidence is consistent with the toxin being a gentamicin derivative.

Simple Measurement of Isepamicin, a New Aminoglycoside Antibiotic, in Guinea Pig and Human Plasma, Using High-Performance Liquid Chromatography with Ultraviolet Detection

Isepamicin, the 1-N-(S-alpha-hydroxy-beta-aminopropionyl) derivative of gentamicin B, is a new aminoglycoside antibiotic, which not only has most of the properties of amikacin but also is effective against several amikacin-resistant strains of bacteria. The drug was assayed in guinea-pig and human plasma with a high-performance liquid chromatographic procedure using precolumn derivatization with 1-fluoro-2,4-dinitrobenzene and ultraviolet detection. Linearity was established over the range 0.5-40 micrograms/ml using 50 microliters of plasma. Accuracy has a mean relative error of less than 3% and precision a mean coefficient of variation of 5%. Isepamicin was determined without interference from plasma constituents or other drugs commonly prescribed during aminoglycoside therapy. This procedure correlates well with radioimmunoassay and can be used either in experimental studies or therapeutic monitoring of plasma levels.

Pretreatment of prosthetic valve sewing-ring with the antibiotic/fibrin sealant compound as a prophylactic tool against prosthetic valve endocarditis

Prosthetic valve endocarditis (PVE) remains a dreaded complication following heart valve replacement despite perioperative antibiotic (AB) prophylaxis. In order to increase the AB concentration in the sewing ring, an experimental study including topical application of the gentamicin derivative EMD 46/217 and fibrin sealant (F) as AB-carrier was initiated. In vitro pretreatment of Dacron with the gentamicin derivative and F was followed by constant AB release for 3 weeks. In a subsequent animal study, four Dacron rings with different pretreatment were implanted in the descending aorta of 10 pigs after direct contamination with 10(8) Staphylococcus aureus solution. One ring was pretreated with the AB/F compound, a second ring with the AB alone. Ring 3 (no pretreatment) and ring 4 (F alone) served as controls. After 1 week, the sewing rings and their corresponding implantation sites were assayed for measurement of AB-content and for culture. The AB content of AB/F-rings was 24.99 +/- 7.16 micrograms/g wet weight, while rings pretreated with the AB alone contained no measurable drug amounts with the exception of one specimen (0.5 microgram/g) (AB/F vs. AB-rings: P less than 0.0005). The corresponding implantation sites to AB/F rings contained 1.07 +/- 0.54 micrograms/g AB, whereas in only 2 of 10 implantation sites of AB rings, low AB levels were found (0.05 and 0.2 micrograms/g) (AB/F vs. AB ring implantation sites: P less than 0.0005). While all control rings and 9 of 10 AB rings were infected, 5 of 10 AB/F rings remained sterile after culture (AB/F vs. AB rings: P = 0.05). This finding correlated with the AB content in the suture rings.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of column packing material and inorganic cations on the separation of fluorescent O-phthalaldehyde derivatives of gentamicin by high-performance liquid chromatography

Reported differences in the order of elution of fluorescent o-phthalaldehyde derivatives of gentamicins C 1, C 1a and C 2 on apparently similar reversed-phase HPLC systems are explained. The differences arise from the relatively higher sensitivity of the κ value of the gentamicin C 1 derivative to the presence of cations in the eluting solvent. This effect also depends on the commercial source of the bonded ODS phase used and is inversely related to the surface coverage of the silica with alkyl chains. The evidence suggests that this phenomenon results from an interaction between the residual silanol groups on the column support and secondary amino groups on the gentamicin derivatives, the C 1 derivative differing from the C 1a and C 2 derivatives in having two rather than only one such group.

Transformation of cultured Drosophila melanogaster cells with a dominant selectable marker.

We have developed a method for the stable and efficient introduction of foreign DNA into Drosophila melanogaster tissue culture cells. A plasmid vector was constructed that carries the bacterial neomycin resistance gene under the transcriptional control of the copia transposable element long terminal repeat promoter. After calcium phosphate-DNA transfection, this vector rendered D. melanogaster cells resistant to the aminoglycoside G-418, a derivative of gentamicin. The vector DNA appeared to be integrated in long tandem arrays of 10 to 20 copies per cell and was stable for many generations in the absence of selection. To test the usefulness of this system for introducing nonselected DNA into D. melanogaster cells, a gene fusion between the P transposable element and the hsp70 promoter was inserted into the copia-neomycin resistance plasmid. After transfection and establishment of a G-418-resistant cell line, the hsp-P fusion gene was found to be efficiently transcribed after heat shock.

Transformation of cultured Drosophila melanogaster cells with a dominant selectable marker.

We have developed a method for the stable and efficient introduction of foreign DNA into Drosophila melanogaster tissue culture cells. A plasmid vector was constructed that carries the bacterial neomycin resistance gene under the transcriptional control of the copia transposable element long terminal repeat promoter. After calcium phosphate-DNA transfection, this vector rendered D. melanogaster cells resistant to the aminoglycoside G-418, a derivative of gentamicin. The vector DNA appeared to be integrated in long tandem arrays of 10 to 20 copies per cell and was stable for many generations in the absence of selection. To test the usefulness of this system for introducing nonselected DNA into D. melanogaster cells, a gene fusion between the P transposable element and the hsp70 promoter was inserted into the copia-neomycin resistance plasmid. After transfection and establishment of a G-418-resistant cell line, the hsp-P fusion gene was found to be efficiently transcribed after heat shock.

D.c. polarographic determination of certain aminoglycosides.

A polarographic method for the quantitative determination of kanamycin, gentamicin and amikacin in a pure form or in pharmaceutical dosage forms has been developed. The method is based on the preparation of the polarographically active nitroso detivatives of these compounds and their polarographic behaviour in both alkaline and acidic media has been studied. The nitroso derivative of kanamycin exhibits one cathodic wave at –1.8 V in alkaline medium and one at –0.8 V in acidic medium. The nitroso derivative of gentamicin shows three well defined cathodic waves at –0.4, –0.8 and –1.4 V in basic medium and two waves at –0.8 and 1.4 V in acidic medium. The nitroso derivative of amikacin shows two cathodic waves at –0.8 and –1.4 V in basic medium and at –0.4 and –0.8 V in acidic medium. A rectilinear relationship exists between the diffusion current and concentration in the ranges 10–60, 10–80 and 10–60 mg-% for kanamycin, gentamycin and amikacin with average recoveries of 99.4 ± 1.4, 99.1 ± 0.95 and 99.7 ± 1.1%, respectively.

A 2'guanidyl derivative of gentamicin (S86451) with reduced nephrotoxicity studies at low and medium dose levels in the rat.

The nephrotoxic potential of S86451 (2'guanidyl, 2'deamino gentamicin C1) has been investigated in Sprague-Dawley rats at 10 and 25 mg/kg, in comparison with gentamicin at 4 and 10 mg/kg. The criteria were (i) the severity of the lysosomal phospholipidosis, as assessed by both biochemical and morphological investigations; (ii) the degree of tubular regeneration, a consequence of the aminoglycoside-induced focal necrosis measured by 3H-thymidine incorporation into kidney cortex DNA. S86451 was found at least 2-5 times less toxic than gentamicin. Thus, this compound should be a safer antibiotic than gentamicin in combating organisms with a similar sensitivity to either drug.

Production and characterization of monoclonal antibody to gentamicin.

Splenocytes from BALB/c mice immunized with a gentamicin-hemocyanin conjugate were fused with X63-Ag8.653 murine myeloma cells to produce hybridomas that secreted monoclonal antibody to gentamicin. Sixteen positive clones were obtained. The monoclonal antibody chosen for a gentamicin immunoassay has been characterized with respect to class, subclass, type of light chain, electrophoretic homogeneity, and binding affinity. Gentamicin monoclonal antibody purified from mouse ascites fluid was analyzed by immunoelectrophoresis, double immunodiffusion, enzyme-linked immunosorbent assay (ELISA), and polyacrylamide gel electrophoresis (PAGE). The results show that the antibody is an IgG2a (kappa). Two bands were detected when the purified antibody was electrophoresed on polyacrylamide gels: a major band and a less mobile minor component (5.6% of the major band). Both were IgG2a (kappa). The major band contained antibody which bound 2.1 moles of the substrate-labeled gentamicin derivative, beta-galactosyl-umbelliferone sisomicin, per mole of IgG, whereas one mole of the minor band bound only 0.095 moles of the substrate-labeled conjugate. The antibody has an affinity constant of 1.22 X 10(10) M-1.