Serum Gentamicin Research Articles

Phylogenetic Analysis Based on Whole Genome Sequences, Antibiotic Resistance, and Virulence of Salmonella enterica Clinical Isolates from South Korea.

Salmonella is a major cause of foodborne disease and frequently causes human salmonellosis in South Korea. In this study, we investigated the genome diversity, antimicrobial resistance, and virulence of clinical isolates of Salmonella enterica from South Korea. We collected 42 S. enterica subsp. enterica isolates from two hospitals in South Korea. Whole genome sequences were determined. Serovars and sequence types (STs) based on multilocus sequence typing (MLST) were identified from whole genome sequences. Phylogenetic trees based on whole genome sequences and a minimum spanning tree based on MLST were constructed. Human serum resistance assays and gentamicin protection assays were performed to assess in vitro virulence. Nineteen serovars were identified among 42 clinical isolates, including nine Salmonella Typhi isolates. There were inconsistencies between serogroups and phylogenetic clusters in the phylogenetic tree and minimum spanning tree, but high clonality of S. Typhi was observed. Salmonella Typhi isolates were divided into two clusters, corresponding to ST1 and ST2. Isolates of serovars Typhimurium and I4,[5],12:i:- clustered into a group, and a hybrid isolate between the two serovars was identified. Four ciprofloxacin-resistant isolates were identified among nine S. Typhi isolates, and all isolates of S. Enteritidis and S. Panama were resistant to colistin. The gentamicin protection assay revealed that serogroup D1 was significantly less virulent than the other serogroups. Our study suggests high diversity of S. enterica clinical isolates from South Korea and non-monophyly of serogroups. In addition, subgroups of S. Typhi isolates and a hybrid isolate between serovars Typhimurium and I4,[5],12:i:- were identified.

Assessing the efficacy of a novel sperm-washing medium enriched with serotonin, L-carnitine, and coenzyme Q10: an observational cohort study.

This observational cohort study investigated the potential of a novel sperm-washing medium (SWM) enriched with serotonin (5-HT), L-carnitine (L-C), and coenzyme Q10 (CoQ10) to enhance sperm motility and reduce DNA damage. It compared this innovative medium (5-HT/L-C/CoQ10 SWM) with two widely used commercial media (SWM 1 and SWM 2). Ninety-eight volunteers from an infertility clinic provided semen samples, which were divided into three aliquots for analysis in different SWMs: group 1, SWM was composed of hydroxyethyl piperazineethanesulfonic acid (HEPES), sodium bicarbonate, human serum albumin (HSA), taurine, and gentamicin sulfate (SWM 1); group 2, SWM was composed of HEPES, sodium bicarbonate, and HSA (SWM 2); and group 3, SWM was composed of HEPES-buffered human tubal fluid supplemented with 5-HT, L-C, and CoQ10 (5-HT/L-C/CoQ10 SWM). Sperm motility was categorized as progressive, nonprogressive, or immotile. Apoptosis, reactive oxygen species (ROS) production, and DNA fragmentation were also assessed. There were no significant differences in total or progressive sperm motility among the groups. Spermatozoa in group 3 exhibited reduced apoptosis, necrosis, and ROS levels and increased viability. No significant differences were observed in the DNA fragmentation index among groups. The 5-HT/L-C/CoQ10 SWM reduced sperm oxidative stress and apoptosis compared with those of the two commercially available SWMs, suggesting that 5-HT/L-C/CoQ10 SWM could be useful for enhancing in vitro fertilization success rates.

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.

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

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. 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-1β) immune-histochemical study were detected. GM significantly increased uterine oxidative stress, inflammatory and apoptotic biomarkers. Histopathological picture of uterine damage and increased IL-1β 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-1β immunoexpression. Vinpo protective effect against GM-induced uterine injury involves modulation of inflammasome/caspase-1/IL-1β signaling pathway.

Three-minute nebulization of gentamicin in healthy dogs results in therapeutic concentrations in bronchoalveolar lavage fluid while remaining below the toxic range values in blood.

To determine and compare the concentration of gentamicin in the lower airways and serum of healthy spontaneously breathing dogs after nebulization with 5% undiluted gentamicin during 3 versus 10 minutes. 10 healthy experimental Beagles. This was a prospective crossover study. A standardized bronchoalveolar lavage (BAL) procedure was performed in each dog after 1 week of administration of each of 2 different gentamicin nebulization protocols separated by a 1-week washout period. The 2 protocols consisted of nebulization of 5% undiluted gentamicin (50 mg/mL) twice daily either during 10 minutes per session (± 95 mg; 10-minute protocol) or 3 minutes per session (± 28 mg; 3-minute protocol). BAL fluid (BALF) was obtained under general anesthesia using a bronchoscope within 15 minutes after administration of the last nebulization. Blood was collected within 5 minutes after BALF collection. BALF and serum gentamicin concentrations were determined by particle-enhanced turbidimetric inhibition immunoassay. Concentrations between protocols were compared using a paired t test. Both BALF and serum gentamicin concentrations were higher after the 10-minute protocol compared with the 3-minute protocol (mean ± SD: 2.41 ± 0.87 mg/L vs 1.25 ± 0.31 mg/L, P = .001; and 1.02 ± 0.59 mg/L vs 0.31 ± 0.24 mg/L, P < .0001 in BALF and serum, respectively), while the BALF-to-serum ratio did not differ between the protocols (3.75 [1.37 to 5.75] (median [IQR]) in the 3-minute protocol vs 2.48 [2.02 to 2.67] in the 10-minute protocol; P = .754). A 3-minute nebulization of gentamicin seems to achieve sufficient concentrations of gentamicin in the BALF to have good efficacy against aminoglycoside-sensitive bacteria while remaining below the toxic range values in blood.

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.

Post Thawing Survival Rate Of Human Embryos In Slow Freezing Versus Vitrification: A Narrative Review

The study compared the outcomes of slow-freeze and vitrification methods for oocyte cryopreservation, analyzing five randomized controlled trials, two cohort studies, and eight systematic reviews and meta-analyses.Slow-freezeis performed at room temperature using a buffered medium supplemented with gentamicin and human serum albumin. It contains 1.5 M 1,2-propanediol and 0.1 M sucrose. On the other hand, vitrification has been the preferred method since 2007. During vitrification, embryos are initially incubated in a solution consisting of 7.5% ethylene glycol and 7.5% dimethyl sulfide, both in Ham's F-10 media. This solution is further supplemented with 20% Albuminal-5. After the initial recovery, the oocytes are aspirated and immersed in a vitrification solution composed of Ham's F-10 medium for a duration of 50 to 60 seconds. The cooling is done via liquid nitrogen, and embryos are stored for months. The survival rate of embryos is the percentage of those that survive after being warmed up. Live birth rates are calculated as the percentage of live births per transferred embryo and warmed embryo. Embryos are selected by biopsy at the zygote or blastocyst stage using non-invasive methods to optimize the success rates of in vitro fertilization. Vitrification has a greater success rate, better survival rates, and transferable embryos, it is chosen for oocyte cryopreservation. Better clinical pregnancy rates and implantation capacity have also been linked to it, notably for blastocysts from In Vitro Maturation programs. To assess effects on neonatal outcomes and congenital abnormalities, additional study is necessary.

Neonatal Serum Gentamicin Concentrations and Outcomes Following Maternal Once-Daily Gentamicin Dosing.

This study evaluated newborn gentamicin serum concentrations after birth and the effects on the newborn after extended interval gentamicin dosing in peripartum mothers. This was a single-center, retrospective chart review of neonates born to mothers that received peripartum once-daily gentamicin dosing of approximately 5 mg/kg within 12 hours of delivery. A gentamicin serum concentration was obtained immediately after birth in the newborn. The primary outcome was initial neonatal gentamicin serum concentration after birth. Several secondary outcomes were evaluated including nephrotoxicity and ototoxicity. A subgroup analysis comparing baseline demographics of mother-newborn dyads with birth neonatal serum concentrations of less than 2 mcg/mL versus 2 mcg/mL or greater was performed. A total of 32 mother-newborn dyads were included. Newborns had a median gestational age of 39.4 weeks and median birth weight of 3.4 kg. The mean initial gentamicin serum concentration was elevated at 3.1 ± 1.9 mcg/mL among all newborns. The median maternal dose based on actual body weight in newborns with gentamicin serum concentrations less than 2 mcg/mL was 3.5 (IQR, 3.3-4.8) mg/kg versus 4.8 (IQR, 4.3-5.2) mg/kg in those that had serum concentrations of 2 mcg/mL or greater (p = 0.025). All newborn gentamicin serum concentrations were less than 2 mcg/mL for maternal doses given less than 1 hour prior to delivery (n = 8). There were no significant differences in nephrotoxicity or ototoxicity. Peripartum once daily dosing of gentamicin administered between 1 to 12 hours of birth may lead to clinically significant serum concentrations in newborns.

Assessing the Risk of Nephrotoxicity Associated with Aminoglycosides in Brucellosis Patients: A Cross-sectional Study.

The purpose of this study was to investigate renal function in patients with brucellosis before and at the end of gentamicin therapy. To ensure the safety of therapeutic doses of gentamicin, renal functions in brucellosis patients were monitored regarding drug serum levels and check for early detection biomarkers of nephrotoxicity. In this cross-sectional study, 41 patients (25 men and 16 women, aged over 15 years) were included, with confirmed acute brucellosis that referred to Brucellosis Research Center in Hamadan, west of Iran between March 2018 to February 2019. At baseline before treatment (first step) and 7 days after gentamicin administration (second step), serum uric acid, blood urea nitrogen (BUN), serum and urine creatinine, erythrocyte sedimentation rate (ESR), quantitative C-reactive protein (CRP) and urinary β2-microglobulin (β2M) were measured. Gentamycin serum level due to the highest risk of nephrotoxicity with this drug in aminoglycoside class was also checked by HPLC method. The data were analyzed using SPSS version 22. The mean urinary β 2M level, serum and urinary creatinine, uric acid, BUN, and quantitative CRP levels in the first step and second step, there were no statistical differences between the two steps. There was a correlation between urinary creatinine and ESR. In addition, a positive correlation was found between urinary β2M and serum gentamicin level. ESR levels have been significantly reduced in the patients after the treatment compared to before it. Our findings confirm that gentamicin is safe at the dose of 5 mg/kg/day for one week intravenously in brucellosis patients.

Intranasal and Serum Gentamicin Concentration: Comparison of Three Topical Administration Protocols in Dogs.

Antimicrobials' topical administration efficacy has not been assessed in dogs with upper respiratory tract disease. The aim was to compare the concentration of gentamicin in nasal lavage fluid (NALF) and in serum after three topical protocols. This was a prospective crossover study of ten healthy dogs. Gentamicin was nebulized for a duration of 1 week, twice a day, for 10 min in the first protocol (10-min protocol) and for 3 min in the second protocol (3-min protocol), while the third protocol consisted of the administration of 0.25 mL of gentamicin in each nostril (drop protocol). Median concentrations of gentamicin in NALF were 9.39 µg/mL (8.12-19.97 interquartile range), 4.96 µg/mL (4.60-6.43) and 137.00 µg/mL (110.5-162.00) in the 10-min protocol, 3-min protocol and drop protocol, respectively. The result for the drop protocol was significantly higher than those of both nebulization protocols in NALF (p = 0.039). In serum, the gentamicin concentration was 0.98 µg/mL (0.65-1.53) and 0.25 µg/mL (0.25-0.44) in the 10-min and 3-min protocols, respectively. Gentamicin was not detected in the serum of seven out of ten dogs in the drop protocol, and gentamicin was significantly higher in the 10-min protocol compared to the drop protocol (p = 0.001). This study found that the 10-min, 3-min and drop protocols achieved superior concentrations in NALF compared to the minimum inhibitory concentration for gentamicin-sensitive bacteria, while remaining below the toxic values in blood.

Gentamicin serum concentration measurement in children.

Gentamicin is often used to treat serious paediatric infections. It has been standard practice in Norway to measure the serum concentration of gentamicin immediately prior to the second or third dose (pre-dose [trough] concentration) to assess the risk of toxicity. The clinical significance of such measurements in children has not previously been evaluated in Norway. This is a retrospective study of routine pre-dose samples obtained for the measurement of serum gentamicin in paediatric patients aged 1 month to 17 years at four hospitals in Norway. Clinical data were extracted from electronic medical records from two of the hospitals. All children received treatment with intravenous gentamicin at a dose of 7mg/kg once daily in accordance with Norwegian guidelines. The most common indications for treatment were febrile urinary tract infection, febrile neutropenia, and suspected or confirmed sepsis. The median (interquartile range) duration of treatment in 353 episodes at two of the hospitals was 4 (3-5) days. Serum gentamicin pre-dose samples were analysed for 1,288 treatment episodes across four hospitals. In 1,223 episodes (95%), the pre-dose sample showed a serum gentamicin concentration of less than 0.6mg/L. In 7 episodes (0.5%), the pre-dose sample showed an elevated gentamicin concentration, defined as greater than 1.0mg/L. An in most cases mildly elevated serum gentamicin concentration was found in the pre-dose sample in 7 of 1,288 treatment episodes. Routine measurement of serum gentamicin via a pre-dose sample should in future be reserved for children receiving long-term gentamicin treatment, those with impaired kidney function, or those who are also receiving nephro- or ototoxic drugs.

Targeting Lower Serum Trough Concentrations: A New Gentamicin Dosing Strategy for Suspected Neonatal Early-Onset Sepsis.

Neonatal gentamicin dosing algorithms are not designed to achieve serum trough concentrations ≤1 mcg/mL. The purpose of our study was to evaluate a new gentamicin algorithm based on serum creatinine (SCr) and gestational age (GA) designed to achieve serum gentamicin trough concentrations ≤1 mcg/mL. A retrospective cohort study was conducted in a level IIIB neonatal intensive care unit. The incidence of elevated serum gentamicin troughs for this study was compared with the center's previously published results to evaluate the proposed dosing algorithm. Patients were included if gentamicin was administered within the first 7 days of life and a serum gentamicin trough concentration and a baseline SCr concentration were obtained. Patients were further subdivided into groups based on GA for data analysis: ≤30 weeks (group 1), 30-34 weeks (group 2), and ≥35 weeks (group 3). The SCr was considered mildly elevated (0.81-0.99 mg/dL) or elevated (≥1 mg/dL). The respective outcomes between the post-algorithm and control groups were examined using intention-to-treat analysis and Bayesian modeling to calculate rate differences. Of the 2377 patients evaluated, 366 met the inclusion criteria. Significantly lower percentages of elevated serum gentamicin troughs were noted in groups 2 and 3 subsequent to the implementation of the dosing algorithm with 16% and 15% lower rate differences, respectively. Regardless of GA, there were significantly fewer elevated serum troughs in the post-implementation groups than in the control with mildly elevated and elevated SCr p < 0.001. Using a dosing algorithm based on SCr significantly reduced the number of elevated serum trough rates in neonates with a GA greater than 30 weeks.

Intravesical gentamicin treatment for recurrent urinary tract infections: A systematic review over the last two decades

Objectives: Recurrent urinary tract infections (rUTIs) have a significant effect on a patient’s quality of life and frequent use of antibiotics increases multi-drug resistance. Previous research on intravesical antibiotics suggests that this has a local effect on bacteria with reduced systemic absorption and associated side effects. We conducted a systematic review to assess the effectiveness and adverse effects of intravesical gentamicin treatment. Methods: Systematic review of all English published articles from January 2001 to October 2021 according to the Cochrane and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. Results: A total of 139 studies were identified, 20 full-text articles were screened and 6 subsequently included totalling 166 patients. All studies reported a decrease in the mean number of urinary tract infections (UTIs) with a significant reduction ( p = 0.0025 and p &lt; 0.004) in two studies. When the number of breakthrough UTIs on prophylactic gentamicin installations was assessed, 65% ( n = 86/133) remained UTI free. Throughout treatment, 99% of serum gentamicin levels were &lt;0.3 ng/dL, and reported instances of increased creatinine were low (2%). A decrease in the growth of multi-drug-resistant bacteria was reported in two papers ( p = 0.065 and p = 0.04). Conclusion: Intravesical gentamicin seems to be an effective treatment in patients with symptomatic rUTIs. The evidence suggests it also reduces UTIs caused by multi-drug-resistant bacteria with no systemic absorption and minimal renal toxicity. Level of evidence: 2a

Physiologically-based pharmacokinetic modelling and dosing evaluation of gentamicin in neonates using PhysPK.

Each year, infections caused around the 25% of neonatal deaths. Early empirical treatments help to reduce this mortality, although optimized dosing regimens are still lacking. The aims were to develop and validate a gentamicin physiologically-based pharmacokinetic (PBPK) model and then potentially explore dosing regimens in neonates using pharmacokinetic and pharmacodynamic criteria. The PBPK model developed consisted of 2 flow-limited tissues: kidney and other tissues. It has been implemented on a new tool called PhysPK, which allows structure reusability and evolution as predictive engine in Model-Informed Precision Dosing (MIPD). Retrospective pharmacokinetic information based on serum levels data from 47 neonates with gestational age between 32 and 39 weeks and younger than one-week postnatal age were used for model validation. The minimal PBPK model developed adequately described the gentamicin serum concentration-time profile with an average fold error nearly 1. Extended interval gentamicin dosing regimens (6 mg/kg q36h and 6 mg/kg q48h for term and preterm neonates, respectively) showed efficacy higher than 99% with toxicity lower than 10% through Monte Carlo simulation evaluations. The gentamicin minimal PBPK model developed in PhysPK from literature information, and validated in preterm and term neonates, presents adequate predictive performance and could be useful for MIPD strategies in neonates.

Intravesical gentamicin instillation in the prevention of recurrent urinary tract infections in children with neurogenic bladder- a single-center retrospective observational study

Recurrent urinary tract infections (UTI) in children with neurogenic bladder (NGB) put them at high risk of morbidity and mortality from urosepsis and end-stage renal disease (ESRD). Since the efficacy of low-dose prophylactic antibiotics to prevent these recurrences has been declining since the emergence of extended-spectrum beta-lactamase (ESBL) organisms, intravesical gentamicin instillation has also been used, but only scarce data in children is available in the literature. We evaluate the efficacy of intravesical gentamicin instillation to reduce UTIs in children with NGB, compare it with oral antibiotic prophylaxis and determine its effect on pathogens resistance to antibiotics. Retrospective observational study of 17 children with NGB managed in a tertiary center. Intravesical gentamicin instillation followed an initial period of oral antibiotic prophylaxis. In a conditional negative binomial regression model, a matched comparison of the rate of UTIs, the identified pathogens and their antibiotics susceptibility between the two therapies was performed for each individual child, RESULTS: When compared to antibiotic prophylaxis, intravesical gentamicin instillation showed no significant difference in the yearly rate of UTI, symptomatic UTI, or admissions for intravenous antibiotic therapy. However, it was associated with a 38% reduction in the incidence rate ratio of UTI (p=0.04) and 75% of asymptomatic UTI (p=0.006) After intravesical gentamicin instillation, five children (31%) had a gentamicin-resistant UTI, similar to before that treatment (p=0.76). Although the overall rate of UTI and of asymptomatic infections were significantly lower with intravesical gentamicin instillation than during oral antibiotic therapy, there was no significant difference in the rate of symptomatic UTIs or UTIs requiring admissions, probably because of the small sample size. In addition, neither an emergence of ESBL pathogens nor the rate of pathogens resistance to gentamicin was observed with intravesical gentamicin instillation. As to the potential nephrotoxicity of aminoglycosides, the calculated GFR for all children remained normal. Strengths of our study include the use of a matched paired comparison of each participant with him/herself with each treatment modality, thus eliminating potential confounding by some individual characteristics. In addition, and unlike previous studies, we have also used a robust multivariate statistical analysis to compare counts and rates of outcomes. Limitations include the absence of gentamicin serum levels monitoring, of hearing testing, and also the small sample size. Intravesical gentamicin instillation decreases the overall rate of UTI and asymptomatic infections in children with NGB without increasing the rate of bacterial resistance to gentamicin.

An Antibiotic-Loaded Hydrogel Demonstrates Efficacy as Prophylaxis and Treatment in a Large Animal Model of Orthopaedic Device-Related Infection.

Local antibiotic therapy is increasingly being recognised for its role in preventing and treating orthopaedic device-related infection (ODRI). A bioresorbable, injectable gentamicin-loaded hydrogel has been developed to deliver local antibiotics at the time of surgery with potential for both prevention and treatment of ODRI. In a prophylaxis model, the antibiotic hydrogel was compared with systemic perioperative antibiotic prophylaxis alone in twelve sheep (six per group) at the time of intramedullary (IM) nail insertion to the tibia, which was inoculated with methicillin-sensitive Staphylococcus aureus (MSSA). In a treatment model of single-stage revision surgery, adjunctive antibiotic-loaded hydrogel was compared with systemic antibiotics alone in a single stage revision of MSSA infection associated with a tibia intramedullary nail in eleven sheep (five/six per group). The primary endpoint was quantitative microbiological results of soft tissue, bone and sonicate fluid from explanted hardware at the time of euthanasia. At euthanasia, the control sheep that received no local antibiotics in the prophylaxis model were all culture-positive (median 1x108, range 7x106-3x108 colony forming units, CFU) while only two of six sheep receiving local gentamicin had any culture positive biopsies (median 1x101, range 0 - 1x105 CFU). For the treatment model, sheep receiving only systemic antibiotics were all culture-positive (median 8x105, range 2x103- 9x106 CFU) while only two of six sheep treated with gentamicin-loaded hydrogel had any culture positive biopsies (median 3x102, range 0 - 7x104 CFU). Local gentamicin concentrations measured in extracellular fluid in the tibial canal show a burst release of gentamicin from the hydrogel. Serum gentamicin concentrations peaked in both models at one day post application and were below detection limit thereafter. This study has demonstrated the effective use of a locally delivered antibiotic hydrogel for both the prevention and treatment of ODRI that is superior to that of systemic antibiotics alone. Future studies will endeavour to translate from preclinical to clinical research trials.

La concentration sérique de gentamicine est-elle modifiée par une autotransfusion sanguine par cell-saver après une arthroplastie totale du genou avec de l’acide tranexamique ? Un essai contrôlé randomisé

BackgroundSelf-transfusion has been proven as an effective management of blood loss after total knee arthroplasty (TKA). Considering that the high local concentration of antibiotic from bone cement is delivered intravenously through the self-transfusion process, systematic toxicity has never been evaluated. In addition, the effectiveness of self-transfusion with the routine concomitant use of other modern blood-salvage strategies, like tranexamic acid, should also be assessed. Therefore we performed a randomized study to assess: (1) the safety of self-transfusion in TKA by comparing the gentamicin concentrations resulting from the use or not of autologous blood transfusion; (2) the efficacy of self-transfusion in TKA, with the concomitant administration of tranexamic acid. HypothesisSelf-transfusion in TKA elevates the serum gentamicin concentration and the potential risk of nephrotoxicity. MethodsThe serum concentration of aminoglycosides was measured in two groups of 20 patients each, after TKA, according to the use of self-transfusion. Hemoglobin, renal function and calculated blood loss were compared at several points in time between groups. ResultsThe only time where there was a statistically significant difference in serum gentamicin, was at 48h postoperatively between groups [0.3 ug/ml±0.21, range: 0.15 to 0.72 vs. 0.14ug/ml±0.1, range: 0 to 0.35 (p=0.02)]. There were no significant differences in total blood loss [1341ml±501, range: 830 to 2230 vs. 1263ml±459 range: 840 to 2480 (p=0.67)] and need of allogeneic blood transfusion [3 units vs. 2 units] between groups. ConclusionThe use of autologous blood transfusion was found to be safe, in terms of nephrotoxicity of aminoglycosides after TKA, but it seemed to be ineffective as a blood salvage strategy, when used concomitantly with the administration of tranexamic acid. Level of EvidenceII; low powered randomized study. ClinicalTrials.gov registration numberNCT04505748.

PEGylation of poly(hydroxybutyrate) into multicomponent nanostructures and loading thereon with bioactive molecules for potential biomedical applications

Polymeric nanostructures (NSs) have achieved significant attention, in recent years, in drug delivery systems. Poly(hydroxybutyrate) and poly(ethylene glycol) being, respectively, hydrophobic and hydrophilic biodegradable polymers have been chosen to develop multicomponent NSs on adding poly(vinyl alcohol) as a stabilizer using the emulsion solvent evaporation technique. The prepared multicomponent NSs were loaded with separate bioactive molecules like bovine serum albumin, gentamicin sulfate, and urea. The z-average DLS analysis demonstrated that the smallest multicomponent NSs observed were of size 300 ± 10 nm under certain process conditions. The scanning electron microscopy exhibited the spherical morphology of the prepared NSs. The Fourier transform infrared spectroscopy expressed H-bonding between the multicomponent moieties. The x-ray diffraction analysis revealed reduced crystallinity of the loaded than that of unloaded multicomponent NSs. We observed a controlled release of bioactive species from the loaded multicomponent NSs. The results demonstrated that the prepared multicomponent NSs may be used as carriers of drugs and other bioactive molecules in various biomedical applications.

21 Invitro maturation of domestic cat oocytes: A comparison of different reproductive stages

Domestic cat invitro embryo production (IVEP) begins with IVM of oocytes to produce mature oocytes; that is, MII. The domestic cat (Felis catus) has been used as a model to carry out assisted reproductive technology (ART) research for application in wild feline species that may be threatened or endangered. The objective of this research was to evaluate oocyte maturation of domestic cats in different reproductive stages: (1) prepubertal, (2) oestrus, (3) pregnant, and (4) anoestrus. The present study was carried out at the Universidad Autónoma Metropolitana Unidad Xochimilco in Mexico City. Unless otherwise stated, all reagents used were from Sigma-Aldrich. The domestic cat ovaries were obtained from a veterinary clinic using salpingo-oophorectomy hysterectomy (OSH). Ovaries were classified as one of the following: (1) prepubertal (female cats under 6 months of age); (2) in oestrus (one or more 2-mm mature follicles); (3) pregnant (presence of fetuses with one or more corpora lutea; and (4) anoestric (ovaries without follicular activity). The ovaries were transported (&amp;lt;2h) in NaCl solution (0.157M) with ampicillin (10 000 IU mL−1), streptomycin (10 000 µg mL−1) and amphotericin (25µg mL−1) to the laboratory. The cumulus–oocyte complexes (COCs) were obtained by ovary microdissection with modified Tyrode’s medium supplemented with sodium lactate (10mM), HEPES (0.50mM) and polyvinyl alcohol (0.01%). COCs were washed twice with TCM-199 medium with Earle’s salts supplemented with bovine serum albumin (BSA, 3mg mL−1), cysteine (0.1mg mL−1), HEPES (1.4mg mL−1), sodium pyruvate (0.25mg mL−1), sodium lactate (0.6mg mL−1), L-glutamine (0.15mg mL−1) and gentamicin (0.055mg mL−1). The wash medium was also used for IVM, but supplemented with human menopausal hormone (Merional® IBSA; 4.5IU mL−1). Oocyte maturation was performed with TCM-199 medium supplemented with BSA, in an atmosphere of 38.5°C, 5% CO2, 95% air, and humidity at saturation for 48h. To evaluate IVM, 300μg mL−1 of hyaluronidase was used to remove the granulosa cells for 5min at 38°C. Next, the oocytes were fixed with paraformaldehyde (4%) for 15 min; washed with a mounting solution (Imacel, invitro); then, 1.5μg mL−1 of 4’,6 diamidino-2-phenylindole dihydrochloride (DAPI) was added. The stained oocytes were evaluated under a microscope (Eclipse E600, Nikon) equipped with a fluorescence lamp and a UV filter (excitation: 330–380nm). The Student’s t-test and the Chi-squared test (χ2) were used for statistical analyses (α=P&amp;lt;0.05). A total of 210 ovaries were obtained from 105 female cats: prepubertal (n=38), oestrus (n=25), pregnant (n=18), and anoestrus (n=24), with a total of 1405 oocytes recovered. The meiotic maturation between the different reproductive stages after 48h of culture was similar in prepubertal (48%), oestrus (46%), pregnant (43%), and anoestrus (45%) groups and did not show a significant difference (P&amp;gt;0.05). This study shows that the domestic cat reproductive stage does not significantly affect the production of mature oocytes for use in ART.

1314. Neonatal Serum Gentamicin Concentrations following Maternal Once-daily Gentamicin Dosing

BackgroundGentamicin is commonly used for peripartum infections. Given literature supporting efficacy of once-daily dosing (ODD) of 5 mg/kg for chorioamnionitis, University of Chicago Medicine made the change from three times daily dosing (TIDD) to ODD. As gentamicin readily cross the placenta, it would be expected that maternal ODD would result in higher gentamicin neonatal serum concentrations following birth.MethodsThis was a single-center, retrospective chart review of all neonates born to mothers receiving peripartum ODD gentamicin within 12 hours of delivery between October 2019 and March 2020. A STAT random gentamicin serum concentration was obtained upon admission in neonates when initiation of antibiotics was desired. Specific dosing recommendations (Table 1) were developed utilizing neonatal population-based pharmacokinetics. The primary outcome was initial neonatal gentamicin serum concentration at birth. Other outcomes were also evaluated. Results were evaluated in two groups based on neonatal serum concentrations of less than 2 mcg/mL (Group 1) versus 2 mcg/mL or greater (Group 2).Table 1: Neonatal gentamicin dosing algorithm ResultsThirty-two mother-newborn dyads were included in this study. Baseline demographics are shown in Table 2. Newborns had a median gestational age of 39.4 weeks and median birth weight of 3.39 kilograms. The mean initial gentamicin concentration was supratherapeutic at 3.06 + 1.92 mcg/mL among all newborns (Table 3). The mean maternal dose in Group 1 (n=11) was 3.52 mg/kg (3.34, 4.77) based on actual body weight and 4.78 mg/kg (4.34, 5.18) in Group 2 (n=21) (p=0.025). The median time between maternal gentamicin administration and time of delivery varied between the groups at 0.5 hours versus 2.63 hours, respectively (p=0.005). All newborn gentamicin concentrations were less than 2 mcg/mL for maternal doses given less than 1 hour prior to delivery (n=8) (Figure 1). Overall protocol compliance rate was 81.3%. There were no significant differences in nephrotoxicity or ototoxicity between groups.Table 2. Baseline Demographics Table 3. Outcomes Figure 1. Comparison of maternal gentamicin time from administration to delivery and neonatal serum gentamicin concentrations ConclusionThis study suggests peripartum ODD of gentamicin may lead to clinically significant serum concentrations in neonates if administered between 1 to 12 hours of birth. Further studies are warranted to evaluate the effects of maternal ODD of gentamicin on newborns.Disclosures All Authors: No reported disclosures