Pharmacokinetics of Aminoglycosides

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.

Optimization and Comparisons for Separation, Detection and Quantification of 12 Aminoglycosides Using 2 Chromatographic Conditions by LC-MS/MS

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.

Safety in Surgery:Evaluation of Safety and Efficiency in Use of Aminoglycosides in Acute Appendicitis

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.

Pharmacodynamics of aminoglycosides and tetracycline derivatives against Japanese encephalitis virus

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.

Detection of aac(3)IIc, aac(6)Ib, armA Genes Coding for Escherichia coli Resistance to Aminoglycosides in Burkina Faso

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.

Felodipine enhances aminoglycosides efficacy against implant infections caused by methicillin-resistant Staphylococcus aureus,persisters and biofilms

Methicillin-resistant Staphylococcus aureus(MRSA),biofilms,and persisters are three major factors leading to recurrent and recalcitrant implant infections.Although antibiotics are still the primary treatment for chronic implant infections in clinical,only few drugs are effective in clearing persisters and formed biofilms.Here,felodipine,a dihydropyridine calcium channel blocker,was reported for the first time to have antibacterial effects against MRSA,biofilm,and persisters.Even after continuous exposure to sub-lethal concentrations of felodipine,bacteria are less likely to develop resistance.Besides,low doses of felodipine enhances the antibacterial activity of gentamicin by inhibiting the expression of protein associated with aminoglycoside resistance(aacA-aphD).Next,biofilm eradication test and persisters killing assay suggested felodipine has an excellent bactericidal effect against formed biofilms and persisters.Furthermore,the result of protein profiling,and quantitative metabonomics analysis indicated felodipine reduce MRSA virulence(agrABC),biofilm formation and TCA cycle.Then,molecular docking showed felodipine inhibit the growth of persisters by binding to the H pocket of ClpP protease,which could lead to substantial protein degradation.Furthermore,murine infection models suggested felodipine in combination with gentamicin alleviate bacterial burden and inflammatory response.In conclusion,low dose of felodipine might be a promising agent for biomaterial delivery to enhance aminoglycosides efficacy against implant infections caused by MRSA,biofilm,and persisters.

Synthesis of a series of guanidine substituted derivatives of aminoglycosides

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.

Convenient synthesis of urea-linked hydroxyl-alkylamine derivatives of aminoglycosides

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.

Design,synthesis,and bioassay of 5-epi-aminoglycosides

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.

Synthesis of a series of guanidine substituted derivatives of aminoglycosides

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.

Molecular Docking Studies on Streptomycin Antileishmanial Activity

Resistance to pentavalent antimonial drugs and the lack of vaccines make it urgent to find novel therapeutic options to treat Leishmaniasis, a tropical disease caused by the Leishmania protozoan parasite. The study reported here is to investigate if Streptomycin, an aminoglycoside, and Amphotericin B, the second-line treatment drug, exhibit antileishmanial activity through a similar mechanism. By using MOE (Molecular Operating Environment), we performed molecular docking studies on these drugs binding to a range of targets including ribosome targets in Leishmania and H. sapiens. Our study shows that the two drugs do not bind to the same pockets in Leishmania targets but to the same pockets in the human ribosome, with some differences in interactions. Moreover, our 2D maps indicated that Amphotericin B binds to the A-site in the human cytoplasmic ribosome, whereas streptomycin does not.

耳蜗传出神经系统和氨基糖苷类抗生素耳中毒

耳蜗传出神经系统在正常听觉和氨基糖苷类抗生素耳中毒中发挥着重要的作用,本文复习近年来相关文献,对耳蜗传出神经系统的形态、生理、耳蜗机械特性和听觉反应的调控机制的研究近况以及氨基糖苷类抗生素对耳蜗传出神经系统的影响进行综述。

Mitochondrial rRNA and tRNA and hearing function

The human ear is a delicate sensory apparatus of hearing for normal communication, and its proper functioning is highly dependent on mitochondrial oxidative phosphorylation. The first mitochondrial point mutation for nonsyndromic and aminoglycoside-induced hearing loss was identified in 1993. Since then a number of inherited mitochondrial mutations have been implicated in hearing loss. Most of the molecular defects responsible for mitochondrial disorder-associated hearing loss are mutations in the 12S rRNA gene and tRNA genes. In this review, after a short description of normal hearing mechanisms and mitochondrial genetics, we outline the recent advances that have been made in the identification of deafness-associated mitochondrial mutations, and discuss how mitochondrial dysfunction contributes to hearing loss.

Mitochondrial DNA mutations associated with aminoglycoside induced ototoxicity

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.

The Central Cattle Breeding and Dairy Farm, Bangladesh waste contributes in emergence and spread of aminoglycoside-resistant bacteria

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.

Sensorineural Hearing Loss in Multidrug-Resistant Tuberculosis Patients in Kinshasa (Democratic Republic of Congo): Prospective Cohort Study of Therapeutic Regimen with Aminoglycoside versus Bedaquiline

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.

Selective protection of ribostamycin by cyclic carbamates

Aim To develop a novel selective protection strategy for the synthesis of ribostamycin cyclic carbamate derivatives. Methods Ribostamycin protected by carbobenzoxy group was treated with Nail, to give different protected intermediates under respective controllable cyclization reaction conditions. New ribostamycin derivative was obtained after the cleavage of carbobenzoxy groups. Result The novel selective protection of ribostamycin was achieved by the synthesis of protected intermediates. New ribostamycin derivative was obtained, but showed no expected antibacterial activity. Conclusion Several ribostamycin cyclic carbamate derivatives were obtained by novel selective protection strategy, which shows the practicability and convenience of the protection strategy. But these new ribostamycin derivatives containing cyclic carbamates structure may not be an ideal leading compound for antibiotic activity.

Synthesis and biological evaluation of neamine analogues for RNA binding

To design and synthesize neamine analogues modified at 5 position offing Ⅱ, which could improve the binding affinity of aminoglycosides to 16S RNA. Started from neomycin B, modified neamine analogues were synthesized through organic reactions such as hydrolysis, protection, nucleophilic substitution, deprotection and reduction. The interaction of the target compounds with A-site RNA in E. coli. ribosome （16S RNA） was determined by surface plasmon resonance （SPR）, respectively. Six target compounds were synthesized. Some of them showed antibacterial activities and enhanced affinity to 16S RNA at 10^-3M in vitro. Introduction amino or aliphatic amino group at 5 position offing Ⅱ in neamine would maintained antibacterial activities as well as increase binding affinity to 16S RNA. Furthermore, there is almost no influence on the stability of drug/16S RNA complex by inverting the configuration of 5-hydroxyl group at ring Ⅱ.

Prevalence and trends of aminoglycoside resistance in Shigella worldwide, 1999-2010

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.

Mitochondrial DNA Mutations Associated with Aminoglycoside Ototoxicity

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.