Revisiting the Evidence Base Informing the Use of Adjunctive Therapy for Enterococcus faecalis Endocarditis: A Systematic Review and Meta-Analysis.

BACKGROUND: Current guidelines recommend adjunctive gentamicin for the treatment of Enterococcus faecalis infective endocarditis (EFIE) despite a risk of toxicity. We sought to revisit the evidence for adjunctive therapy in EFIE and to synthesize the comparative safety and effectiveness of adjunctive use of the aminoglycosides versus ceftriaxone by systematic review and meta-analysis. METHODS: For historical context, we reviewed the seminal case series and in vitro studies informing the evolution from penicillin monotherapy to modern-day regimens for EFIE. Next, we searched MEDLINE and Embase from inception to January 16, 2024 for studies of EFIE comparing 1) adjunctive aminoglycosides versus ceftriaxone or 2) adjunctive therapy versus monotherapy. Where possible, clinical outcomes were compared between regimens by random-effects meta-analysis. Otherwise, data were narratively summarized. RESULTS: Results for the systematic review and meta-analysis were limited to 10 observational studies totaling 911 patients. All studies were at high risk of bias. Relative to adjunctive ceftriaxone, gentamicin had similar all-cause mortality (Risk Difference [RD]=-0.8%, 95% Confidence interval [95%CI]=-5.0, 3.5), relapse (RD=-0.1%, 95%CI=-2.4, 2.3), and treatment failure (RD=1.1%, 95%CI=-1.6, 3.7), but higher discontinuation due to toxicity (RD=26.3%, 95%CI=19.8, 32.7). The 3 studies comparing adjunctive therapy to monotherapy included only 30 monotherapy patients and heterogeneity precluded meta-analysis. CONCLUSION: Adjunctive therapy with ceftriaxone appeared to be equally effective and less toxic than gentamicin for the treatment of EFIE. The existing evidence does not clearly establish the superiority of either adjunctive therapy or monotherapy. Pending randomized evidence, if adjunctive therapy is to be used, ceftriaxone appears to be a reasonable option.

Preventive nasal administration of flagellin restores antimicrobial effect of gentamicin and protects against a multidrug-resistant strain of Pseudomonas aeruginosa.

The increasing prevalence of multidrug-resistant Pseudomonas aeruginosa (PA) is a significant concern for chronic respiratory disease exacerbations. Host-directed drugs, such as flagellin, an agonist of toll-like receptor 5 (TLR5), have emerged as a promising solution. In this study, we evaluated the prophylactic intranasal administration of flagellin against a multidrug-resistant strain of PA (PAMDR) in mice and assessed the possible synergy with the antibiotic gentamicin (GNT). The results indicated that flagellin treatment before infection decreased bacterial load in the lungs, likely due to an increase in neutrophil recruitment, and reduced signs of inflammation, including proinflammatory cytokines. The combination of flagellin and GNT showed a synergistic effect, decreasing even more the bacterial load and increasing mice survival rates, in comparison to mice pre-treated only with flagellin. These findings suggest that preventive nasal administration of flagellin could restore the effect of GNT against MDR strains of PA, paving the way for the use of flagellin in vulnerable patients with chronic respiratory diseases.

Gentamicin concentration and acute kidney injury in term neonates treated for neonatal sepsis with gentamicin and ampicillin-cloxacillin combination.

Gentamicin is widely used to treat neonatal infections caused by both Gram-negative and Gram-positive bacteria, and the WHO recommends its use while monitoring serum creatinine and gentamicin concentrations to avoid drug-induced nephrotoxicity and ototoxicity. Yet in some resource-limited settings, the drug is used without monitoring. A population pharmacokinetics study involving term neonates with neonatal infection admitted to a neonatal unit. Participants were started on intravenous gentamicin 5 mg/kg once a day in combination with ampicilin-cloxacillin. Blood samples for serum gentamicin concentration were taken at 0.25, 0.5, 1, 2, 3, 5, 6, 8, 10, 12, 14, 16, 18, 20, 23, and 24 hours after the initial dose, each participant contributing two samples to the 24 hour sampling schedule. An additional sample for trough concentration was taken from each participant just before the third gentamicin dose while serum creatinine concentration was measured before and after treatment. Twenty-four participants were enrolled into the study and included in the final analysis. Mean (SD) peak and trough serum gentamicin concentrations were 16.66 (0.64) µg/mL and 3.28 (0.70) µg/mL, respectively. Gentamicin clearance (CL) was 0.40 mL min-1 kg-1 and volume of distribution (VD) was 0.31 L kg-1. Mean (SD) serum creatinine level after treatment was 209.7 (70.4) µmol/L compared to 103.3 (23.6) µmol/L before treatment [mean difference (106.4 ± 67.1; 95% confidence interval (CI): 78.1; 134.7 µmol/L; t (23) = 7.77; P < 0.001]. All participants fulfilled the Kidney Disease Improving Global Outcomes (KDIGO) criteria for acute kidney injury after treatment. Treatment of neonatal infection with antimicrobial regimen containing gentamicin, without renal function and gentamicin concentration monitoring, carries a significant risk for drug-induced acute kidney injury.

Improved characterization of aminoglycoside penetration into human lung epithelial lining fluid via population pharmacokinetics.

Aminoglycosides are important treatment options for serious lung infections, but modeling analyses to quantify their human lung epithelial lining fluid (ELF) penetration are lacking. We estimated the extent and rate of penetration for five aminoglycosides via population pharmacokinetics from eight published studies. The area under the curve in ELF vs plasma ranged from 50% to 100% and equilibration half-lives from 0.61 to 5.80 h, indicating extensive system hysteresis. Aminoglycoside ELF peak concentrations were blunted, but overall exposures were moderately high.

Increased tolerance to commonly used antibiotics in a Pseudomonas aeruginosa ex vivo porcine keratitis model.

Introduction. Bacterial keratitis, particularly caused by Pseudomonas aeruginosa, is challenging to treat because of multi-drug tolerance, often associated with the formation of biofilms. Antibiotics in development are typically evaluated against planktonic bacteria in a culture medium, which may not accurately represent the complexity of infections in vivo.Hypothesis/Gap Statement. Developing a reliable, economic ex vivo keratitis model that replicates some complexity of tissue infections could facilitate a deeper understanding of antibiotic efficacy, thus aiding in the optimization of treatment strategies for bacterial keratitis.Methodology. Here we investigated the efficacy of three commonly used antibiotics (gentamicin, ciprofloxacin and meropenem) against Pseudomonas aeruginosa cytotoxic strain PA14 and invasive strain PA01 using an ex vivo porcine keratitis model.Results. Both strains of P. aeruginosa were susceptible to the MIC of the three tested antibiotics. However, significantly higher concentrations were necessary to inhibit bacterial growth in the minimum biofilm eradication concentration (MBEC) assay, with both strains tolerating concentrations greater than 512 mg l-1 of meropenem. When MIC and higher concentrations than MBEC (1024 mg l-1) of antibiotics were applied, ciprofloxacin exhibited the highest potency against both P. aeruginosa strains, followed by meropenem, while gentamicin showed the least potency. Despite this, none of the antibiotic concentrations used effectively cleared the infection, even after 18 h of continuous exposure.Conclusions. Further exploration of antibiotic concentrations and aligning dosing with clinical studies to validate the model is needed. Nonetheless, our ex vivo porcine keratitis model could be a valuable tool for assessing antibiotic efficacy.

Identification and mechanism determination of the efflux pump subunit amrB gene mutations linked to gentamicin susceptibility in clinical Burkholderia pseudomallei from Malaysian Borneo.

The bacterium Burkholderia pseudomallei is typically resistant to gentamicin but rare susceptible strains have been isolated in certain regions, such as Thailand and Sarawak, Malaysia. Recently, several amino acid substitutions have been reported in the amrB gene (a subunit of the amrAB-oprA efflux pump gene) that confer gentamicin susceptibility. However, information regarding the mechanism of the substitutions conferring the susceptibility is lacking. To understand the mechanism of amino acid substitution that confers susceptibility, this study identifies the corresponding mutations in clinical gentamicin-susceptible B. pseudomallei isolates from the Malaysian Borneo (n = 46; Sarawak: 5; Sabah: 41). Three phenotypically confirmed gentamicin-susceptible (GENs) strains from Sarawak, Malaysia, were screened for mutations in the amrB gene using gene sequences of gentamicin-resistant (GENr) strains (QEH 56, QEH 57, QEH20, and QEH26) and publicly available sequences (AF072887.1 and BX571965.1) as the comparator. The effect of missense mutations on the stability of the AmrB protein was determined by calculating the average energy change value (ΔΔG). Mutagenesis analysis identified a polymorphism-associated mutation, g.1056 T > G, a possible susceptible-associated in-frame deletion, Delta V412, and a previously confirmed susceptible-associated amino acid substitution, T368R, in each of the three GENs isolates. The contribution of Delta V412 needs further confirmation by experimental mutagenesis analysis. The mechanism by which T368R confers susceptibility, as elucidated by in silico mutagenesis analysis using AmrB-modeled protein structures, is proposed to be due to the location of T368R in a highly conserved region, rather than destabilization of the AmrB protein structure.

Stop codon readthrough as a treatment option for epidermolysis bullosa-Where we are and where we are going.

In the context of rare genetic diseases caused by nonsense mutations, the concept of induced stop codon readthrough (SCR) represents an attractive avenue in the ongoing search for improved treatment options. Epidermolysis bullosa (EB)-exemplary for this group of diseases-describes a diverse group of rare, blistering genodermatoses. Characterized by extreme skin fragility upon minor mechanical trauma, the most severe forms often result from nonsense mutations that lead to premature translation termination and loss of function of essential proteins at the dermo-epidermal junction. Since no curative interventions are currently available, medical care is mainly limited to alleviating symptoms and preventing complications. Complementary to attempts of gene, cell and protein therapy in EB, SCR represents a promising medical alternative. While gentamicin has already been examined in several clinical trials involving EB, other potent SCR inducers, such as ataluren, may also show promise in treating the hitherto non-curative disease. In addition to the extensively studied aminoglycosides and their derivatives, several other substance classes-non-aminoglycoside antibiotics and non-aminoglycoside compounds-are currently under investigation. The extensive data gathered in numerous in vitro experiments and the perspectives they reveal in the clinical setting will be discussed in this review.

A physiological approach to renal clearance: From premature neonates to adults.

AIMS: We propose using glomerular filtration rate (GFR) as the physiological basis for distinguishing components of renal clearance. METHODS: Gentamicin, amikacin and vancomycin are thought to be predominantly excreted by the kidneys. A mixed-effects joint model of the pharmacokinetics of these drugs was developed, with a wide dispersion of weight, age and serum creatinine. A dataset created from 18 sources resulted in 27,338 drug concentrations from 9,901 patients. Body size and composition, maturation and renal function were used to describe differences in drug clearance and volume of distribution. RESULTS: This study demonstrates that GFR is a predictor of two distinct components of renal elimination clearance: (1) GFR clearance associated with normal GFR and (2) non-GFR clearance not associated with normal GFR. All three drugs had GFR clearance estimated as a drug-specific percentage of normal GFR (gentamicin 39%, amikacin 90% and vancomycin 57%). The total clearance (sum of GFR and non-GFR clearance), standardized to 70 kg total body mass, 176 cm, male, renal function 1, was 5.58 L/h (95% confidence interval [CI] 5.50-5.69) (gentamicin), 7.77 L/h (95% CI 7.26-8.19) (amikacin) and 4.70 L/h (95% CI 4.61-4.80) (vancomycin). CONCLUSIONS: GFR provides a physiological basis for renal drug elimination. It has been used to distinguish two elimination components. This physiological approach has been applied to describe clearance and volume of distribution from premature neonates to elderly adults with a wide dispersion of size, body composition and renal function. Dose individualization has been implemented using target concentration intervention.

In vitro susceptibility of Neisseria gonorrhoeae to netilmicin and etimicin in comparison to gentamicin and other aminoglycosides.

PURPOSE: Single doses of gentamicin have demonstrated clinical efficacy in the treatment of urogenital gonorrhea, but lower cure rates for oropharyngeal and anorectal gonorrhea. Formulations selectively enriched in specific gentamicin C congeners have been proposed as a less toxic alternative to gentamicin, potentially permitting higher dosing to result in increased plasma exposures at the extragenital sites of infection. The purpose of the present study was to compare the antibacterial activity of individual gentamicin C congeners against Neisseria gonorrhoeae to that of other aminoglycoside antibiotics. METHODS: Antimicrobial susceptibility of three N. gonorrhoeae reference strains and 152 clinical isolates was assessed using standard disk diffusion, agar dilution, and epsilometer tests. RESULTS: Gentamicin C1, C2, C1a, and C2a demonstrated similar activity against N. gonorrhoeae. Interestingly, susceptibility to the 1-N-ethylated aminoglycosides etimicin and netilmicin was significantly higher than the susceptibility to their parent compounds gentamicin C1a and sisomicin, and to any other of the 25 aminoglycosides assessed in this study. Propylamycin, a 4'-propylated paromomycin analogue, was significantly more active against N. gonorrhoeae than its parent compound, too. CONCLUSION: Selectively enriched gentamicin formulations hold promise for a less toxic but equally efficacious alternative to gentamicin. Our study warrants additional consideration of the clinically established netilmicin and etimicin for treatment of genital and perhaps extragenital gonorrhea. Additional studies are required to elucidate the mechanism behind the advantage of alkylated aminoglycosides.

Gentamicin combination treatment is associated with lower mortality in patients with invasive listeriosis: a retrospective analysis.

PURPOSE: Listeria monocytogenes causes severe bacterial infections with the highest mortality rate among foodborne pathogens in Europe. Combination treatment with ampicillin and gentamicin is recommended for invasive manifestations. However, evidence to support this treatment approach remains limited due to a lack of randomised controlled trials. To explore this critical issue further, we conducted this retrospective, single-center study. METHODS: We identified all patients hospitalized with invasive listeriosis at the University Medical Center Hamburg-Eppendorf between 2009 and 2020 and analyzed the effect of gentamicin combination treatment versus monotherapy on 90-day mortality. RESULTS: In total, 36 patients with invasive listeriosis were included, of which 21 patients received gentamicin combination treatment and 15 received monotherapy. The mean age-adjusted Charlson Comorbidity Index (aaCCI) value was lower in the gentamicin combination treatment group (5.4 vs. 7.4). Neurolisteriosis was more common in the gentamicin group (81% vs. 20%). The 90-day mortality was with significantly lower in the gentamicin combination treatment group (10%) compared to the monotherapy group (60%). Multivariable cox regression analysis, adjusted for a propensity score computed based on neurolisteriosis, aaCCI and sex, revealed a significantly reduced hazard ratio of 0.07 (95% CI: 0.01-0.53, p = 0.01) for 90-day mortality for the gentamicin combination treatment. CONCLUSION: This retrospective study highlights the benefit of gentamicin combination treatment in reducing the 90-day mortality rate among patients with invasive listeriosis. The high prevalence of monotherapy in this study cohort raises concerns about the adequacy of antibiotic therapy in clinical practice.

Enhancement of bactericidal effects of bacteriophage and gentamicin combination regimen against Staphylococcus aureus and Pseudomonas aeruginosa strains in a mice diabetic wound model.

Diabetic patients are more susceptible to developing wound infections resulting in poor and delayed wound healing. Bacteriophages, the viruses that target-specific bacteria, can be used as an alternative to antibiotics to eliminate drug-resistant bacterial infections. Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) are among the most frequently identified pathogens in diabetic foot ulcers (DFUs). The aim of this study was assessment of bacteriophage and gentamicin combination effects on bacterial isolates from DFU infections. Specific bacteriophages were collected from sewage and animal feces samples and the phages were enriched using S. aureus and P. aeruginosa cultures. The lytic potential of phage isolates was assessed by the clarity of plaques. We isolated and characterized four lytic phages: Stp2, Psp1, Stp1, and Psp2. The phage cocktail was optimized and investigated in vitro. We also assessed the effects of topical bacteriophage cocktail gel on animal models of DFU. Results revealed that the phage cocktail significantly reduced the mortality rate in diabetic infected mice. We determined that treatment with bacteriophage cocktail effectively decreased bacterial colony counts and improved wound healing in S. aureus and P. aeruginosa infections, especially when administrated concomitantly with gentamicin. The application of complementary therapy using a phage cocktail and gentamicin, could offer an attractive approach for the treatment of wound diabetic bacterial infections.

Protective role of citronellol on antioxidant enzymes and oxidative damage induced by gentamicin in experimental nephrotoxic rats.

BACKGROUND: Gentamicin leads to nephrotoxicity with increasing oxidative stress. In the present research the role of citronellol on oxidative damage induced by gentamicin in nephrotoxic rats was evaluated. METHODS AND RESULTS: Forty-twomale Wistar rats were randomly divided into seven equal groups; healthy control, gentamicin, DMSO, citronellol 50, citronellol 100, citronellol 200 and vitamin E. The animals were anesthetized after 12 days of treatment. Kidney and serum samples were received for biochemical, histological changes, and gene expression assessments. The levels of serum glutathione (GSH), serum and kidney glutathione peroxidase (GPX) and the expression of GPX gene against gentamicin group were increased in citronellol treatment groups. The levels of serum and kidney malondialdehyde (MDA), urine protein, serum creatinine and the gene expression of inflammatory factors including tumor necrosis factor-alpha (TNF-α) and Interleukin 6 (IL-6) against gentamicin group were decreased in these groups. Moreover, recuperation in histological alterations was shown in three groups receiving citronellol compared to the gentamicin group. CONCLUSIONS: Citronellol with its antioxidant and anti-inflammatory properties can decrease kidney damage caused by nephrotoxicity induced by gentamicin.

The ameliorative effect of vinpocetine against gentamicin-induced uterine-injury in rats involves the inflammasome/caspase-1/IL-1ß pathway.

BACKGROUND: There is limited data regarding the hazardous effect of gentamicin (GM) on the uterus and whether or not vinpocetine (Vinpo) ameliorates it. The present study aimed to identify the possible protective effect of Vinpo in GM-induced uterine injury in rats. METHODS: Female rats were assorted in control-group, Vinpo-group, GM-group, and Vinpo plus GM group. Serum and uterine GM concentration were measured. Uterine oxidative stress parameters besides inflammatory and apoptotic biomarkers were evaluated. Uterine histopathological examination and interlukin-1beta (IL-1ß) immune-histochemical study were detected. RESULTS: GM significantly increased uterine oxidative stress, inflammatory and apoptotic biomarkers. Histopathological picture of uterine damage and increased IL-1ß immunoexpression were detected. Vinpo significantly ameliorated the distributed GM concentration, oxidative stress, inflammatory and apoptotic biomarkers with a prompt improvement in histopathological picture and a decrease in IL-1ß immunoexpression. CONCLUSION: Vinpo protective effect against GM-induced uterine injury involves modulation of inflammasome/caspase-1/IL-1ß signaling pathway.

Antimicrobial peptides and proteins as alternative antibiotics for porcine semen preservation.

BACKGROUND: Antimicrobial resistance (AMR) is nowadays a major emerging challenge for public health worldwide. The over- and misuse of antibiotics, including those for cell culture, are promoting AMR while also encouraging the research and employment of alternative drugs. The addition of antibiotics to the cell media is strongly recommended in sperm preservation, being gentamicin the most used for boar semen. Because of its continued use, several bacterial strains present in boar semen have developed resistance to this antibiotic. Antimicrobial peptides and proteins (AMPPs) are promising candidates as alternative antibiotics because their mechanism of action is less likely to promote AMR. In the present study, we tested two AMPPs (lysozyme and nisin; 50 and 500 µg/mL) as possible substitutes of gentamicin for boar semen preservation up to 48 h of storage. RESULTS: We found that both AMPPs improved sperm plasma membrane and acrosome integrity during semen storage. The highest concentration tested for lysozyme also kept the remaining sperm parameters unaltered, at 48 h of semen storage, and reduced the bacterial load at comparable levels of the samples supplemented with gentamicin (p > 0.05). On the other hand, while nisin (500 µg/mL) reduced the total Enterobacteriaceae counts, it also decreased the rapid and progressive sperm population and the seminal oxidation-reduction potential (p < 0.05). CONCLUSIONS: The protective effect of lysozyme on sperm function together with its antimicrobial activity and inborn presence in body fluids, including semen and cervical mucus, makes this enzyme a promising antimicrobial agent for boar semen preservation.

Protective role of pyrroloquinoline quinone against gentamicin induced cochlear hair cell ototoxicity.

Gentamicin (GM) is one of the commonly used antibiotics in the aminoglycoside class but is ototoxic, which constantly impacts the quality of human life. Pyrroloquinoline quinone (PQQ) as a redox cofactor produced by bacteria was found in soil and foods that exert an antioxidant and redox modulator. It is well documented that the PQQ can alleviate inflammatory responses and cytotoxicity. However, our understanding of PQQ in ototoxicity remains unclear. We reported that PQQ could protect against GM-induced ototoxicity in House Ear Institute-Organ of Corti 1 (HEI-OC1) cells in vitro. To evaluate reactive oxygen species (ROS) production and mitochondrial function, ROS and JC-1 staining, oxygen consumption rate (OCR), and extracellular acidification rate (ECAR) measurements in living cells, mitochondrial dynamics analysis was performed. GM-mediated damage was performed by reducing the production of ROS and inhibiting mitochondria biogenesis and dynamics. PQQ ameliorated the cellular oxidative stress and recovered mitochondrial membrane potential, facilitating the recovery of mitochondrial biogenesis and dynamics. Our in vitro findings improve our understanding of the GM-induced ototoxicity with therapeutic implications for PQQ.

Development of a sensitive direct competitive chemiluminescent enzyme immunoassay for gentamicin based on the construction of a specific single-chain variable fragment-alkaline phosphatase fusion protein.

A sensitive chemiluminescent enzyme immunoassay (CLEIA) was established for the determination of gentamicin (GEN) residue levels in animal tissue. This assay is based on a fusion protein of single-chain variable fragment (scFv) and alkaline phosphatase (AP). Initially, VL and VH derived from anti-gentamicin monoclonal antibody were linked by a short peptide to construct a scFv. Subsequently, the constructed scFv sequence was accessed into the pLIP6/GN vector, and a soluble scFv-AP fusion protein was generated. The scFv-AP fusion protein was used to develop a direct competitive CLEIA (dcCLEIA) for the determination of gentamicin. In the dcCLEIA, the half inhibitory concentration (IC50) and limit of detection (LOD) were 1.073 ng/mL and 0.380 ng/mL, respectively. The average recoveries of gentamicin spiked in animal tissue samples ranged from 78% to 96%. These results showed a strong correlation with ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The above results suggest that the anti-GEN scFv-AP fusion protein is suitable for detecting gentamicin residues in edible animal tissues.

Investigation the effects of 2-aminoethoxydiphenyl borate (2-APB) on aminoglycoside nephrotoxicity.

Investigation the protective effect of transient receptor potential channel modulator 2-Aminoethoxydiphenyl Borate (2-APB) on aminoglycoside nephrotoxicity caused by reactive oxygen species, calcium-induced apoptosis and inflammation was aimed. Forty Wistar rats were divided (n=8) as follows: Control group; DMSO group; 2-APB group; Gentamicin group (injected 100 mg/kg gentamicin intramuscularly for 10 days); Gentamicin+ 2-APB group (injected 2 mg/kg 2-APB intraperitoneally, then after 30 minutes 100 mg/kg gentamicin was injected intramuscularly for 10 days). Blood samples were collected for biochemical analyses, kidney tissue samples were collected for light, electron microscopic and immunohistochemical investigations. In gentamicin group glomerular degeneration, tubular dilatation, vacuolization, desquamation of tubular cells and hyaline cast formation in luminal space and leukocyte infiltration were seen. Disorganization of microvilli of tubular cells, apical cytoplasmic blebbing, lipid accumulation, myelin figure like structure formation, increased lysosomes, mitochondrial swelling and disorganization of cristae structures, apoptotic changes and widening of intercellular space were found. TNF-α, IL-6 and caspase 3 expressions were increased. BUN and creatinine concentrations were increased. Increase in MDA levels and decrease in SOD activities were determined. Even though degeneration still continues in gentamicin+2-APB treatment group, severity and the area it occupied were decreased and the glomerular and tubule structures were generally preserved. TNF-α, IL-6, caspase 3 immunoreactivities and BUN, creatinine, MDA concentrations were reduced and SOD activities were increased markedly compared to gentamicin group. In conclusion, it has been considered that 2-APB can prevent gentamicin mediated nephrotoxicity with its anti-oxidant, anti-apoptotic and anti-inflammatory effects.

Enhancing the therapeutic potential of intravenous glycerol for Meniere's disease: Robust results from an extensive patient cohort.

INTRODUCTION: Meniere's disease (MD) is an idiopatic condition characterized by recurrent attacks of vertigo, hearing loss, tinnitus, and aural fullness, affecting quality of life. Intravenous glycerol has shown potential as a therapeutic option. This study evaluates its efficacy in a larger patient cohort. MATERIALS AND METHODS: Retrospective study with 168 patients having unilateral MD unresponsive to dietary restrictions. Intravenous 10 % glycerol with 0.9 % sodium chloride was administered for six months. Audio-vestibular assessments and questionnaires were used. RESULTS: Significant improvements in vertigo control observed. 7.1 % achieved complete control, and 58.3 % had substantial control. Quality of life measures improved, and audiometry thresholds remained unchanged. No major adverse events reported. DISCUSSION: Intravenous glycerol effectively controlled vertigo and improved MD patients' quality of life. Limitations include lack of a control group and a relatively short-term follow-up. Future prospects include randomized controlled trials and optimization of treatment protocols. CONCLUSION: Intravenous glycerol shows promise as a therapeutic option for MD, with notable improvements in vertigo control and quality of life. Further research is needed for validation and optimization.

Efficacy and preservation of hearing with low-dose gentamicin in unilateral meniere's disease: A clinical symptomatology-based study.

PURPOSE: Meniere's disease (MD), a disorder of the inner ear, presents numerous therapeutic challenges, and intratympanic (IT) gentamicin has been proposed for intractable cases. However, controversy regarding dosage and method persists. The purpose of this study was to assess the efficacy and safety of low-dose IT gentamicin on vertigo attacks in MD using a clinical symptomatology-based method, wherein administration was repeated only if vertigo attacks recurred, with a 2-week interval between injections. MATERIALS AND METHODS: This study included 88 patients with unilateral intractable MD. All patients received one to five IT injections with 0.5 ml of 10 mg of gentamicin (80 mg/2 ml) with an interval of 2 weeks between injections. Vertigo attacks were evaluated before and after therapy and categorized into classes A-F according to the 2015 Equilibrium Committee criteria. Audiovestibular assessments, including Pure Tone Audiometry and Vestibulo-Ocular Reflex evaluations, were performed. RESULTS: Before treatment, patients had an average of 4.4 vertigo attacks/month; after treatment, this average decreased to 0.52. The majority of patients (57 %) reached Class A or B vertigo control with five or fewer gentamicin injections. VOR gain was slightly affected on the healthy side and significantly reduced on the affected side. No hearing deterioration was found in any of the treated patients. CONCLUSIONS: Low-dose IT gentamicin administration based on clinical symptomatology can produce a satisfactory control of vertigo attacks after treatment. This protocol primarily affected the vestibular function, as demonstrated by the significant reduction in VOR gain on the affected side, while avoiding cochlear damage. The lack of adverse events and preservation of hearing underscore the safety and efficacy of this method. These findings have significant clinical implications, suggesting that a low-dose, clinical symptomatology-based gentamicin treatment regimen could be an effective and safe strategy for managing unilateral Meniere's disease in a larger population.

The effect of intratympanic gentamicin as a prehabilitation strategy for objective and subjective vestibular function in patients undergoing microsurgery for a unilateral vestibular schwannoma.

OBJECTIVE: To review the literature on intratympanic gentamicin treatment as prehabilitation for patients undergoing surgery for a unilateral vestibular schwannoma. DATA SOURCES: A systematic literature search was conducted up to March 2023 in Pubmed, Embase, Cochrane, Web of Science, Academic Search Premier, Google Scholar and Emcare databases. REVIEW METHODS: Articles on the effect of intratympanic gentamicin followed by vestibular schwannoma surgery were reviewed. Data on objective vestibular function and subjective outcomes were compiled in tables for analysis. Relevance and methodological quality were assessed with the methodological index for non-randomized tool. RESULTS: A total of 281 articles were identified. After screening and exclusion of duplicates, 13 studies were reviewed for eligibility, of which 4 studies could be included in the review. The posturography test, the subjective visual horizontal test, and the optokinetic nystagmus test showed decreased vestibular function in the group of patients who received intratympanic gentamicin before microsurgery compared to the group of patients without gentamicin. Other objective tests did not show significant differences between patient groups. Subjective vestibular outcomes, as evaluated by questionnaires on quality of life and/or dizziness, did not seem to improve from intratympanic gentamicin pretreatment. CONCLUSION: Vestibular schwannoma patients who received intratympanic gentamicin before surgical resection of the tumor performed better in the posturography test, subjective visual horizontal test, and the optokinetic nystagmus test afterwards. However, studies that also evaluated subjective outcomes such as dizziness, anxiety, depression, and balance self-confidence did not show a positive effect of intratympanic gentamicin on the vestibular complaints and symptoms.