Gentamicin Research Articles

Assessment of antibiotics sensitivity of microbial isolates from fish hatcheries

The study assessed the antibiotics sensitivity of bacterial isolates from fish hatcheries. The result revealed that bacteria of public health importance were isolated, however, the TVC did not exceed 105 CFU/g. A total of 16 isolates were detected. Thirteen (13) antibiotics recorded over 50% resistance, with the highest resistance (100%) observed in amoxicillin clavulanate (AUG). Ofloxime (OFX), gentamycin(GN) and levofloxacin (LBC) recorded the lowest resistance of 18.75%, 37.5% and 43.75% respectively. Only these antibiotics with least recorded resistance had susceptibility ranging between 50% (LBC) and 68.75% (OFX). The overall average resistance of the isolates to antibiotics was 68.75%; susceptibility 26.67% and intermediate 4.58%. Isolates 15 showed the highest resistance of 100%, followed by isolates 12 and 10 with 93.33% and 93.33% resistance, respectively. Resistance range of 60% to 86.67% was observed in isolates 2, 4, 5, 6, 7, 9, 13, 14, 16 and 17. Isolates 3, 8 and 11 had resistance below 50% ranging between 26.67% and 46.67%. The highest multiple antibiotic resistance index (MARI) was observed in isolate 15 with MARI of 1. Isolates 10 and 12 had MARI of 0.93. This was followed in descending order by isolates 2 and 9 (0.86), isolate 5 (0.8), isolate 14 (0.73), isolates 6 and 7 (0.67) and isolates 4, 13, 16 and 17 (0.6). The least MARI recorded were observed in isolates 3 and 11 (0.47) and isolate 8 (0.27), respectively. The emergence of antibiotic resistance on fish farms in Ijebu-Ode region calls for public health intervention strategies.Keywords: antibiotic; fish health; isolates; resistance.

Pyruvate dehydrogenase is a potential mitochondrial off-target for gentamicin based on in silico predictions and in vitro inhibition studies

During the drug development process, organ toxicity leads to an estimated failure of one-third of novel chemical entities. Drug-induced toxicity is increasingly associated with mitochondrial dysfunction, but identifying the underlying molecular mechanisms remains a challenge. Computational modeling techniques have proven to be a good tool in searching for drug off-targets. Here, we aimed to identify mitochondrial off-targets of the nephrotoxic drugs tenofovir and gentamicin using different in silico approaches (KRIPO, ProBis and PDID). Dihydroorotate dehydrogenase (DHODH) and pyruvate dehydrogenase (PDH) were predicted as potential novel off-target sites for tenofovir and gentamicin, respectively. The predicted targets were evaluated in vitro, using (colorimetric) enzymatic activity measurements. Tenofovir did not inhibit DHODH activity, while gentamicin potently reduced PDH activity. In conclusion, the use of in silico methods appeared a valuable approach in predicting PDH as a mitochondrial off-target of gentamicin. Further research is required to investigate the contribution of PDH inhibition to overall renal toxicity of gentamicin.

2183. Porin Mutations Potentiate the in Vitro Synergy of Meropenem-Vaborbactam (MVB), but not Ceftazidime-Avibactam (CZA) in Combination with Other Antibiotics against KPC-producing Klebsiella Pneumoniae (KPC-Kp)

Abstract Background CZA and MVB are often used in combination with other antibiotics in clinical practice. Our objective was to assess their in vitro synergy stratified by predominant ompK36 genotype: wild-type (WT), or mutants that included an insertion sequence 5 (IS5) or GD duplication (GD). Methods 15 KPC-Kp clinical isolates were selected. Minimum inhibitory concentrations (MICs) were determined by broth microdilution in triplicate. Time-kill analyses were used to test CZA and MVB alone (1 and 4x MIC) and in combination with colistin (COL; 2 mg/L), fosfomycin (FOS; 100 mg/L + 25 mg/L G6P), gentamicin (GEN; 2 µg/mL), meropenem (MEM; 8 mg/L), and tigecycline (TGC; 2 mg/L) against 1x108 cFu/mL. 24 hour log-kill was calculated as log cFu/mL decrease from time 0. Results 5 isolates each had ompK36 WT, IS5, or GD. 27% and 73% were KPC-3 and KPC-2, respectively. 100% were susceptible to CZA and MVB. None were resistant to COL. 3 were non-susceptible to GEN, which were all IS5 (Table 1). In combination with CZA 1x MIC, each of COL, GEN, and MEM were bactericidal against all isolates; mean ± standard error (SE) log kills were -7.39 ± 0.3, -6.58 ± 0.93, and -5.81 ± 0.21, respectively (Figure 1). Mean log-kills did not vary for CZA + COL, GEN, or TGC against ompK36 mutants vs WT; however, log-kills were significantly lower for CZA + FOS (-3.78 vs -6.6; p < 0.05) or MEM (-5.4 vs -6.62; p < 0.01) against ompK36 mutants compared to WT. Synergy rates were reduced from 100% against WT to 80%, 60%, and 40% against mutant isolates for CZA + COL, MEM, and FOS, respectively (Figure 2). MVB 1x MIC in combination with COL, FOS, GEN, and TGC were bactericidal 67, 27, 80, and 47% of the time, with corresponding log kills of -3.96 ± 1.1, -1.56 ± 0.83, -5.05 ± 0.82, and -2.53 ± 0.28, respectively (Figure 1). Mean ± SE log kills were significantly greater against porin mutants compared to WT for MVB + COL (-5.57 vs -0.73; p = 0.03), FOS (-3.11 vs 1.54; p = 0.03), or TGC (-2.93 vs -1.73; p = 0.04). Rates of synergy were also higher against porin mutants vs WT for MVB + FOS or COL (Figure 2). Table 1 Characteristics and susceptibility data for fifteen KPC-Kp isolates chosen for analysis. CAZ = ceftazidime; COL = colistin; CZA = Ceftazidime-avibactam; FOS = fosfomycin; GD = GD duplication; GEN = gentamicin; IS5 = insertion sequence 5; KPC = Klebsiella pneumoniae carbapenemase; MEM = meropenem; MVB = meropenem-vaborbactam; TGC = tigecycline; WT = wild-type. Figure 1 24-hour log kills for antibiotic combinations with CZA (ceftazidime-avibactam) and MVB (meropenem-vaborbactam) at 1X MIC, stratified by ompk36 status: wild-type (WT) versus mutant (MUT). Bactericidal is defined as -3 log kill from time 0 at 24 hours and indicated by the dotted horizontal line. COL = colistin; FOS = fosfomycin; GEN = gentamicin; MEM = meropenem; MIC = minimum inhibitory concentration; TGC = tigecycline. Figure 2 Proportion of bactericidal, synergistic, and antagonistic outcomes for ompK36 wild-type (WT; n = 5) versus mutant (MUT; n = 10) KPC-Kp isolates tested against CZA (ceftazidime-avibactam) or MVB (meropenem-vaborbactam) at 1X MIC as single agents and in combination with colistin (COL), gentamicin (GEN), tigecycline (TGC), meropenem (MEM), or fosfomycin (FOS). Bactericidal activity was defined as -3 log kill from time 0 at 24 hours; synergy and antagonism were defined as -2 or +2 log kill at 24 hours compared to most active single agent, respectively. Conclusion Porin mutations negatively impact CZA synergy with other antibiotics compared to WT, though 24-hour log kills for COL, FOS, GEN, and MEM remained below the bactericidal threshold. Conversely, porin mutations potentiate synergy between MVB and COL, FOS, or TGC. Disclosures Ryan K. Shields, PharmD, MS, Allergan: Advisor/Consultant|Cidara: Advisor/Consultant|Entasis: Advisor/Consultant|GSK: Advisor/Consultant|Melinta: Advisor/Consultant|Melinta: Grant/Research Support|Menarini: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Roche: Grant/Research Support|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Utility: Advisor/Consultant|Venatorx: Advisor/Consultant|Venatorx: Grant/Research Support

Cortisol Sensitizes Cochlear Hair Cells to Gentamicin Ototoxicity Via Endogenous Apoptotic Pathway.

The widespread use of aminoglycosides is a prevalent cause of sensorineural hearing loss. Patients receiving aminoglycosides usually have elevated levels of circulating stress hormones due to disease or physiological stress; however, whether the stress hormone cortisol impacts aminoglycoside-mediated injury of cochlear hair cells has not been fully investigated. House Ear Institute-Organ of Corti 1 (HEI-OC1) cells with or without cortisol pretreatment were exposed to gentamicin, we investigated the effect of cortisol pretreatment on gentamicin ototoxicity by assessing cell viability. Molecular pathogenesis was explored by detecting apoptosis and oxidative stress. Meanwhile, by inhibiting glucocorticoid receptors (GR) and mineralocorticoid receptors (MR), the potential roles of receptor types in cortisol-mediated sensitization were evaluated. Cortisol concentrations below 75 μmol/l did not affect cell viability. However, pretreatment with 50 μmol/l cortisol for 24 hours sensitized hair cells to gentamicin-induced apoptosis. Further mechanistic studies revealed that cortisol significantly increased hair cell apoptosis and oxidative stress, and altered apoptosis-related protein expressions induced by gentamicin. In addition, blockade of either GR or MR attenuated cortisol-induced hair cell sensitization to gentamicin toxicity. Cortisol pretreatment increased mammalian hair cell susceptibility to gentamicin toxicity. Sensitization was related to the activation of the intrinsic apoptotic pathway and excessive generation of reactive oxygen species. Cortisol may exacerbate aminoglycoside ototoxicity.

Lysosomal membrane stabilization by imipramine attenuates gentamicin-induced renal injury: Enhanced LAMP2 expression, down-regulation of cytoplasmic cathepsin D and tBid/cytochrome c/cleaved caspase-3 apoptotic signaling

Nephrotoxicity is a serious complication commonly encountered with gentamicin (GTM) treatment. Permeabilization of lysosomes with subsequent cytoplasmic release of GTM and cathepsins is considered a crucial issue in progression of GTM toxicity. This study was designed to evaluate the prospective defensive effect of lysosomal membrane stabilization by imipramine (IMP) against GTM nephrotoxicity in rats. GTM (30 mg/kg/h) was intraperitoneally administered over 4 h daily (120 mg/kg/day) for 7 days. IMP (30 mg/kg/day) was orally administered for 14 days; starting 7 days before and then concurrently with GTM. On 15th day, samples (urine, blood, kidney) were collected to estimate biomarkers of kidney function, lysosomal stability, apoptosis, and inflammation. IMP administration to GTM-treated rats ameliorated the disruption in lysosomal membrane stability induced by GTM. That was evidenced by enhanced renal protein expressions of LAMP2 and PI3K, but reduced cathepsin D cytoplasmic expression in kidney sections. Besides, IMP guarded against apoptosis in GTM-treated rats by down-regulation of the pro-apoptotic (tBid, Bax, cytochrome c) and the effector cleaved caspase-3 expressions, while the anti-apoptotic Bcl-2 expression was enhanced. Additionally, the inflammatory cascade p38 MAPK/NF-κB/TNF-α was attenuated in GTM + IMP group along with marked improvement in kidney function biomarkers, compared to GTM group. These findings were supported by the obvious improvement in histological architecture. Furthermore, in vitro enhancement of the antibacterial activity of GTM by IMP confers an additional benefit to their combination. Conclusively, lysosomal membrane stabilization by IMP with subsequent suppression of tBid/cytochrome c/cleaved caspase-3 apoptotic signaling could be a promising protective strategy against GTM nephrotoxicity.

Synthesis, crystal structures, CT-DNA/BSA binding modes and antibacterial activities of Zn(II) and Cr(III) with an acylhydrazone ligand

Two salicylaldehyde-4-hydroxy phenylacetyl acylhydrazone transition metal complexes ZnL2·H2O (I) and [CrL2]NO3·EtOH (II) were synthesized by C15H14N2O3 (HL) with Zn(NO3)2·6H2O and Cr(NO3)3·9H2O. Structures of HL, I and II were characterized by single crystal X-ray diffraction. With the ligand HL belonging to the monoclinic crystal system and the P21/c space group, the coordinating atoms (N and O atoms) in both two complexes I and II exhibited a six-coordinated octahedral geometry centered on the metal ion. Thermal stabilities of the two complexes were analyzed by TG-DTG techniques, which illustrated the maximum thermal decomposition peak temperatures of two complexes were both higher than 170 °C, exhibiting strong thermal stabilities. UV–vis absorption spectroscopy and microcalorimetry were used to determine interaction patterns of I and II with CT-DNA, showing that I and II effectively bound to CT-DNA through the intercalation mode and the interactions processes of I and II with CT-DNA were spontaneous, exothermic entropy reduction reactions. Fluorescence spectroscopy and microcalorimetry were used to determine the interactions of I and II with BSA, presenting that the two complexes can effectively bind to BSA and form non-fluorescent matrix complexes and the interactions processes were spontaneous exothermic and entropy reducing, and each of interaction duration was within 48 min. In addition, the antimicrobial activities of complexes I and II against S. aureus, P. aeruginosa, B. subtilis and E. coli were determined, revealing II exhibited stronger inhibition activity against P. aeruginosa than gentamicin sulfate at 0.5 mg·L-1. Complexes I and II were expected to be used as alternative drugs of gentamicin sulfate in the future.

Intra-soft tissue and intramedullary antibiotic perfusion in combination with negative pressure wound therapy.

Intra-soft tissue and intramedullary antibiotic perfusion (iSAP and iMAP), which combine continuous administration of antibiotic solution to the wound and negative pressure wound therapy (NPWT), have been reported to be a useful management approach for hard-to-heal ulcers in the field of orthopaedic surgery. We report the efficacy of this treatment and discuss the key points. The recipients of this treatment had contaminated fresh severe trauma with a high risk of infection, or hard-to-heal ulcers which were expected to be difficult to manage with conventional NPWT alone. Continuous administration of 1200µg/ml of gentamicin (GM) solution to the wound was performed along with NPWT. The GM solution was administered subcutaneously using a small catheter for iSAP, while intramedullary administration used a bone marrow needle for iMAP. iSAP was employed in all 10 patients who took part, and iMAP in three of these patients. The average treatment time was 13.6 days with iSAP and 9.3 days with iMAP. The mean serum GM level during the therapy was 1.02µg/ml. Moderate GM-induced acute kidney injury was suspected in one case, but resolved spontaneously after GM administration was stopped. Favourable wound bed preparation was achieved in all cases without recurrence of infection. Combination with continuous suction by NPWT is able to keep the local concentration of antibiotic above the minimum inhibitory concentration of biofilm-coated bacteria within the wound. We have referred to this treatment as continuous local antibiotic perfusion. Further investigation of local pharmacodynamics in the wound and side-effects of this treatment are warranted.

Therapeutic Effect of Chitosan-Zinc Oxide Nanoparticles on Acute Kidney Injury Induced by Gentamicin in Wistar Rats

Background: Gentamicin (GM) is an antibiotic frequently used to treat severe gram-negative infections. However, due to nephrotoxicity, its clinical application is restricted. Several lines of evidence indicate that free radicals are important mediators of gentamicin nephrotoxicity. Therefore, the purpose of this research was to examine the potential antioxidant therapeutic value of ZnO-chitosan nanoparticles on gentamicin-induced nephrotoxicity. Methods: Twenty-four rats were divided into four groups (6 rats/group). All groups except group 1 were injected with gentamicin (100 mg/kg body weight i.p.) for eight days. On day 9, rats of groups 1 and 2 were administrated distilled water, and those of groups 3 and 4 were administrated 1/10 and 1/20 LD50 of ZnO-CS-NPs continuously for 30 days. Results: Treatment with ZnO-CS NPs caused a significant decrease in urea, creatinine, uric acid, sodium, potassium, chloride, microalbumin, and malondialdehyde levels; this was accompanied by a significant increase in kidney glutathione reduced, nitric oxide, superoxide dismutase, glutathione S-transferase, and catalase. Conclusion: The findings of the current study revealed that ZnO-CS NP ameliorated kidney injury against gentamicin induced-acute kidney injury in rats by its antioxidant properties.

MICROBIOLOGICAL PROFILE OF HIGH TOUCH AREAS OF CRITICAL AND NON-CRITICAL UNITS IN TEACHING HOSPITAL OF MADHYA PRADESH, INDIA

In the current scenario, Nosocomial infections (NI) due to environmental contamination in shared settings of health care, are a serious public health issue affecting millions of people every year worldwide. Therefore, this study aims to create a microbiological profile of high touch areas of Critical and Non-Critical units in Teaching Hospital of Madhya Pradesh. This Cross-sectional Study deals with bacterial (aerobic and anaerobic) surveillance and its antimicrobial susceptibility testing which will aid in enlisting antimicrobial-resistant bacteria and guide us in the use of antimicrobials judiciously. A total of 128 samples were taken from Critical care units and non-Critical units from eight surface locations classified into categories of immediate patient environment and commonly used equipment. These samples were then processed for isolation and identification by standard methods. Out of 128 samples, 28 (21.8%) samples were culture positive for aerobic only and none for anaerobic bacteria. Among which more culture positive samples were isolated from non-Critical units 53.5%, topping the list of contamination were General Medicine ward and Gynecology ward (17.8 %). The majority of isolated microorganisms were Staphylococcus aureus of which 38.4% were MRSA. It showed maximum resistance for Ampicillin (AMP) and was most sensitive to Gentamicin (GEN). Present study highlights that control of Staphylococcus aureus infection (including MRSA) in hospitals is essential. It can be achieved by proper implementation of hospital infection control measures and regular surveillance activity.

Diagnostic value of inflammatory indicators for surgical site infection in patients with breast cancer

BackgroundBreast cancer is the most commonly diagnostic cancer in women worldwide. The main treatment for these patients is surgery. However, there is a high incidence of surgical site infection (SSI) in breast cancer patients. The aim of this study was to identify effective infection-related diagnostic markers for timely diagnosis and treatment of SSI.MethodsThis retrospective study included 263 breast cancer patients who were treated between July 2018 and March 2023 at the Shandong Cancer Hospital and Institute. We analyzed differences between the SSI group and control group and differences before and during infection in the SSI group. Finally, we tested the distribution of pathogenic microorganisms and their susceptibility to antibiotics.ResultsCompared with preoperative inflammatory indicators, white blood cells (WBC), neutrophils (NEU), absolute neutrophil count to the absolute lymphocyte count (NLR), D2 polymers (D-Dimer) and fibrinogen (FIB) were significantly increased, while lymphocytes (LYM), albumin (ALB) and prealbumin (PA) were significantly decreased in the SSI group. Compared with uninfected patients, WBC, NEU, NLR and FIB were significantly increased, ALB and PA were significantly decreased in SSI patients, while LYM and D-Dimer did not differ significantly. The distribution of infection bacteria in SSI patients showed that the proportion of patients with Staphylococcus aureus infection was as high as 70.41%; of those patients, 19.33% had methicillin-resistant Staphylococcus aureus (MRSA) infection. The area under the curves (AUCs) of the receiver operating curves (ROCs) for WBC, NEU, NLR, FIB, ALB and PA were 0.807, 0.811, 0.730, 0.705, 0.663 and 0.796, respectively. The AUCs for other inflammatory indicators were not statistically significant. There was no significant difference in antibiotic resistance for Staphylococcus aureus when compared to that of gram-positive bacteria. The resistance of gram-positive bacteria to ceftriaxone (CRO), cefoxitin (FOX), chloramphenicol (CHL), minocycline (MNO) and tetracycline (TCY) was lower than that of gram-negative bacteria, while the resistance to gentamicin (GEN) was higher.ConclusionThis study demonstrated that WBC, NEU, NLR, FIB and PA have good predictive value for identifying patients at risk of SSI. The cut-off values of inflammatory indicators can be helpful in the prevention and diagnosis of SSI.

Fabrication of Gentamicin Sulfate‐Loaded 3D‐Printed Polyvinyl Alcohol/Sodium Alginate/Gelatin‐Methacryloyl Hybrid Scaffolds for Skin Tissue Replacement

Abstract3D‐printed scaffolds can better mimic the function of human skin, both biologically and mechanically. Within the scope of this study, the effect of the addition of different amounts (10, 15, 20 mg) of gentamicin sulfate (GS) to a 10 mL solution of natural and synthetic polymers is investigated. Sodium alginate (SA), gelatin‐methacryloyl (GelMA), and polyvinyl alcohol (PVA) are chosen as bioactive materials. The surface morphology and pore structures are visualized by scanning electron microscopy (SEM). According to the results, it is observed that the pore sizes of all scaffolds are smaller than 270 µm, the lowest value (130 µm) is obtained in the scaffold loaded with 15 mg GS, and it also has the highest tensile strength value (12.5 ± 7.6 MPa). Similarly, it is observed that the tensile strength (9.7 ± 4.5 MPa) is high in scaffold loaded with 20 mg GS. The biocompatibility test is performed with fibroblast cells, and the results show that the scaffolds are biocompatible with cells. The antibacterial test is carried out against the S.aureous and E. coli and the results indicate that all GS‐loaded scaffolds demonstrate antibacterial activity.

Combinatorial efficacy of Manuka honey and antibiotics in the in vitro control of staphylococci and their small colony variants

IntroductionStaphylococci are among the list of problematic bacteria contributing to the global antibiotic resistance (ABR) crisis. Their ability to adopt the small colony variant (SCV) phenotype, induced by prolonged antibiotic chemotherapy, complicates staphylococcal infection control options. Novel and alternative approaches are needed to tackle staphylococcal infections and curb ABR. Manuka honey (MH), a non-antibiotic alternative is recognized for its unique antibacterial activity based on its methylglyoxal (MGO) component.MethodsIn this study, MH (MGO 830+) was tested in combination with gentamicin (GEN), rifampicin (RIF), or vancomycin (VA) against staphylococcal wildtype (WT) and SCVs. To our knowledge, there are no current studies in the literature documenting the effects of MH on staphylococcal SCVs. While Staphylococcus aureus is well-studied for its international ABR burden, limited data exists demonstrating the effects of MH on S. epidermidis and S. lugdunensis whose pathogenic relevance and contribution to ABR is also rising.Results & discussionThe three staphylococci were most susceptible to RIF (0.06-0.24 μg/ml), then GEN (0.12-0.49 μg/ml), and lastly VA (0.49-0.96 μg/ml). The MICs of MH were 7%, 7-8%, and 6-7% (w/v), respectively. Fractional inhibitory concentration (FIC) evaluations showed that the combined MH + antibiotic effect was either additive (FICI 1-2), or partially synergistic (FICI >0.5-1). While all three antibiotics induced SCVs in vitro, stable SCVs were observed in GEN treatments only. The addition of MH to these GEN-SCV-induction analyses resulted in complete suppression of SCVs (p<0.001) in all three staphylococci, suggesting that MH’s antibacterial properties interfered with GEN’s SCV induction mechanisms. Moreover, the addition of MH to growth cultures of recovered stable SCVs resulted in the inhibition of SCV growth by at least 99%, indicating MH’s ability to prevent subsequent SCV growth. These in vitro analyses demonstrated MH’s broad-spectrum capabilities not only in improving WT staphylococci susceptibility to the three antibiotics, but also mitigated the development and subsequent growth of their SCV phenotypes. MH in combination with antibiotics has the potential to not only resensitize staphylococci to antibiotics and consequently require less antibiotic usage, but in instances where prolonged chemotherapy is employed, the development and growth of SCVs would be hampered, providing a better clinical outcome, all of which mitigate ABR.

Electrospun composite fibers of poly(lactic acid) and halloysite for the sustained co-delivery of drugs with opposite water affinities

A dual drug delivery system capable of simultaneous release in a sustained manner a hydrophilic and a hydrophobic drug was prepared, consisting of electrospun poly(lactic acid) (PLA) fibers embedded with halloysite nanotubes (Hal). The hydrophobic drug (dexamethasone, DEX) was directly dissolved in the polymer solution and the hydrophilic drug (gentamicin sulfate, GS) was pre-loaded into Hal. Prior to drug loading, Hal were subjected to an acid treatment to enhance their drug loading capacity. The efficacy of the treatment was confirmed by the increase of the BET surface area and pore volume, determined by nitrogen adsorption/desorption isotherm measurements, and by an increase in GS drug loading (from 18% w/w to 25% w/w), determined by thermogravimetry. Morphologically, the fibers with or without Hal exhibited similar smooth surfaces, with no obvious signs of Hal in the composite fibers, indicating that Hal were well embedded in the fibers. In vitro release tests showed the ability of the composite electrospun fibers to release the two loaded drugs simultaneously in a sustained manner for three weeks, in a biphasic pattern characterized by a burst release in the first 2–3 days followed by a gradual, almost constant release. Furthermore, the antibacterial activity of all GS loaded fibers against Staphylococcus aureus was confirmed by a disc diffusion test. In conclusion, the developed electrospun fibers based on a “nanoparticles in micro/nanofibers” structure proved to be an effective system for the sustained co-delivery of two drugs with opposite water affinities.

Encapsulating Antibiotic and Protein-Stabilized Nanosilver into Sandwich-Structured Electrospun Nanofibrous Scaffolds for MRSA-Infected Wound Treatment.

With the increasing prevalence of microbial infections, which results in prolonged inflammation and delayed wound healing, the development of effective and safe antimicrobial wound dressings of multiple properties remains challenging for public health. Despite their various formats, the available developed dressings with limited functions may not fulfill the diverse demands involved in the complex wound healing process. In this study, multifunctional sandwich-structured electrospinning nanofiber membranes (ENMs) were fabricated. According to the structural composition, the obtained ENMs included a hydrophilic inner layer loaded with curcumin and gentamicin sulfate, an antibacterial middle layer consisting of bovine serum albumin stabilized silver oxide nanoparticles, and a hydrophobic outer layer. The prepared sandwich-structured ENMs (SNM) exhibited good biocompatibility and killing efficacy on Escherichia coli, Staphylococcus aureus, and Methicillin-resistant S. aureus (MRSA). In particular, transcriptomic analysis revealed that SNM inactivated MRSA by inhibiting its carbohydrate and energy metabolism and reduced the bacterial resistance by downregulating mecA. In the animal experiment, SNM showed improved wound healing efficiency by reducing the bacterial load and inflammation. Moreover, 16S rDNA sequencing results indicated that SNM treatment may accelerate wound healing without observed influence on the normal skin flora. Therefore, the constructed sandwich-structured ENMs exhibited promising potential as dressings to deal with the infected wound management.

Synthesis, Characterization, and Biological Evaluation of Gabapentinoid Hybrids with Isoindole-1,3(2H)-Dione Moiety as Potential Antioxidant, Antimicrobial, and Anticancer Agents

Purpose. To synthesize new isoindole-1,3(2H)-dione derivatives by molecular hybridization of gabapentin and pregabalin with phthalic anhydride derivatives and to evaluate their biological activity as promising antioxidant, antimicrobial, and anticancer agents. Method. Molecular hybridization was successfully achieved by two procedures; synthesized compounds were characterized using analytical and spectral methods. The free radical scavenging properties of synthesized compounds were evaluated using the DPPH method. The antibacterial activity of synthesized compounds and parent compounds was evaluated against two microbial Gram-positive and Gram-negative strains by the well diffusion method. Furthermore, we have studied the effect of compounds on proliferation, cell cycle, and cell death in two human cancer cell lines (Caco-2 and HCT-116). Results. Compounds 1, 3, and 4 exhibited a good free radical scavenging effect, and compound 3 is the most effective with IC50 value of 2.525 μmol/mL. All compounds showed antibacterial activity against Escherichia coli and Staphylococcus aureus related to concentration, while parent drugs did not exhibit any antibacterial effect. Compounds 1 and 2 showed a good zone of inhibition against E. coli at micromolar concentrations, and they are more effective than Gentamicin Sulfate. Treatment with the studied compounds suppresses proliferation, arrests progress throughout the cell cycle, and induces apoptosis in Caco-2 and HCT-116 cancer cells. Compound 2 is highly effective against Caco-2 cells and more effective than thalidomide, with IC50 value less than 1 μmol/L. Conclusion. Our results showed that molecular hybridization of gabapentin and pregabalin in the isoindole-1,3(2H)-dione moiety results in promising anticancer and antimicrobial molecules. Results of this preliminary study show that halogenation of the isoindole-1,3(2H)-dione moiety improves antimicrobial and anticancer activity and that tetra-brominated derivatives are comparable to or more effective than related tetra-chlorinated derivatives.

Protective effect of <i>Rosemarinus officinalis</i> on gentamicin-induced acute kidney injury in adult male albino rats

Background: Gentamicin (GN) drug is one of the first-line drugs for managing severe gramnegative bacteria. Its association with acute kidney injury (AKI) has restricted its use due to oxidation damage to kidney architectural structures. Rosmarinus Officinalis (rosemary) is anatural antioxidant available and affordable in many developing countries. Antioxidants can be used to prevent oxidation that causes AKI in GN use. This study was undertaken to evaluate the protective gross morphological effect of Rosmarinus Officinalis (RO) on Gentamicin- induced acute Kidney injury in male albino rats’ species of Rattus norvegicus.
 Methodology: The study was done in Kenya at Maseno University. A posttest true experimental design was used, and a sample size of 25 Albino rats was calculated using a resource-modified equation. Rats were randomly sampled into 5 groups, each with 5 albino rats. The negative control group received a standard rat diet plus water, the positive control received GN100,mg/kg/bwt/i.p, low-dose RO, medium-dose RO, and high-dose RO groups received 100,150 and 200 mg/kg/bwt of RO orally, respectively, and were co-administered with GN 100mg/kg/bwt/i.p. At the end of day seven, they were humanely sacrificed, and gross morphometric were taken.
 Results: It was observed that the mean weight of the rat, weight, and volume of the kidney increased significantly (p= 0.001) in high-dose RO group as compared to the positive control. The mean length and thickness in high-dose RO group increased significantly (p=0.0001) as compared to the positive control.
 Conclusion: This present study shows that co-administration of a high dose of RO has a protective effect on gross morphology against Gentamicin-induced AKI among male albino rats.

Vitamin E and Silymarin Reduce Oxidative Tissue Damage during Gentamycin-Induced Nephrotoxicity.

Aminoglycoside antibiotics and gentamicin (GN), in particular, are still widely used in clinical practice. It is a well-known fact that GN causes nephrotoxicity, and redox disturbances are discussed as a factor in its side effects. Recently, a new type of cell oxidative death, named ferroptosis, was discovered; it is associated with iron accumulation in the cell, glutathione (GSH) depletion and inactivation of glutathione peroxidase-4 (GPX4), reactive oxygen species (ROS) increment with concomitant lipid peroxidation. In this regard, a possible connection between GN-induced renal damage, ferroptosis and the overall antioxidant status of the organism could be investigated. Moreover, due to its beneficial effects, GN is still one of the main choices as a therapeutic agent for several diseases, and the possible reduction of its side effects with the application of certain antioxidants will be of important clinical significance. The study was conducted with adult male white mice divided into several groups (n = 6). GN nephrotoxicity was induced by the administration of GN 100-200 mg/kg i.p. for 10 days. The control group received only saline. The other groups received either Vitamin E (400 mg/kg p.o.) or Silymarin (200 mg/kg p.o.) applied alone or together with GN for the same period. After the end of the study, the animals were sacrificed, and blood and tissue samples were taken for the assessment of biochemical parameters and antioxidant status, as well as routine and specific for GPX4 histochemistry examination. The experimental results indicate that GN-induced nephrotoxicity negatively modulates GPX4 activity and is associated with increased production of ROS and lipid peroxidation. The groups treated with antioxidants demonstrated preserved antioxidant status and better GPX4 activity. In conclusion, the inhibition of ROS production and especially the suppression of ferroptosis, could be of clinical potential and can be applied as a means of reducing the toxic effects of GN application.

Bacterial Stomatitis in Wild Reticulated Pythons (Malayopython reticulatus) in Malaysia

Bacterial stomatitis is a common clinical form of upper alimentary tract disease in reptiles. The current study aimed to isolate and identify the common aerobes in the oral cavities of wild reticulated pythons and to profile their antimicrobial susceptibility. The need to conduct the current research was deemed in parallel with the increasing demand for snakes as pets and the growing emergence of multiple-drug-resistant organisms. A total of 40 fresh carcasses of the wild-caught reticulated pythons were assessed for the presence or absence of stomatitis. Oral swabs were obtained and cultured on blood and MacConkey agar media. The colony and cellular morphologies of the isolates were evaluated, followed by Gram-positive and Gram-negative bacterial identification. Antimicrobial susceptibility testing was performed using Kirby-Bauer disk diffusion method against selected antibiotics, namely gentamicin (GEN), amoxicillin (AMX), cephalexin (LEX), azithromycin (AZM), tetracycline (TET), and ciprofloxacin (CIP), commonly used to treat bacterial infection in reptiles. Results indicated that the prevalence of stomatitis was 77.5%. Among 153 isolates identified, 76.47% of bacteria were identified from pythons with stomatitis lesions, while 23.53% of bacteria were identified from pythons without stomatitis. Of 153 isolates, Gram-negative bacteria were shown to be predominant (94.77%). The three most isolated bacterial species were Aeromonas spp. (14.38%), Klebsiella pneumoniae (11.76%), and Alcaligenes faecalis (8.5%). Meanwhile, coagulase-negative Staphylococcus spp. (4.58%) and Corynebacterium spp. (0.66%) were the only isolated Gram-positive aerobes. Most isolates were observed to be equally susceptible to GEN and CIP (at 95.8%) but highly resistant to AMX (83.3%) and LEX (75.0%). In conclusion, bacterial stomatitis in wild-caught reticulated pythons was highly prevalent and often seen as a mixed bacterial infection (96.8%). The isolated bacteria consistently show susceptibility towards GEN and CIP and thus could be considered the primary line of antibiotics in treating this disease.

PH-sensitive bilayer electrospun nanofibers based on ethyl cellulose and Eudragit S-100 as a dual delivery system for treatment of the burn wounds; preparation, characterizations, and in-vitro/in-vivo assessment

A pH-sensitive bilayer electrospun nanofibrous mat containing both antibiotic (gentamicin sulfate, GEN) and non-steroidal anti-inflammatory (diclofenac sodium, DIC) drugs was fabricated for burn wound dressing by electrospinning technique, in which ethyl cellulose (EC) and ethyl cellulose/Eudragit S-100 (EC/ES-100) formed the top and bottom layers, respectively. The fabricated pH-sensitive bilayer electrospun nanofibrous mats were characterized from aspects of both structure and efficiency. Physicochemical properties were investigated via SEM, FTIR, and TGA. The swelling ratio and in vitro drug release of the fabricated nanofibrous mats were studied in different pHs. MTT was applied to assess the safety of the fiber mats. Finally, the in vivo efficiency of the designed pH-sensitive bilayer electrospun nanofibrous mats was examined on the male Wistar rats. Based on the histological analysis and wound healing test (in vivo animal experiments), the (ES100/EC-DIC/GEN)-(EC) pH-sensitive bilayer nanofibrous mat displayed faster wound healing than other bilayer nanofibrous mat. As a result, (ES100/EC-DIC/GEN)-(EC) bilayer nanofibrous mat with pH-responsion could accelerate the burn wound healing process via decreasing the adverse effects of GEN and DIC as topical antimicrobial and anti-inflammatory agents, receptively.

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.