Case analysis of hepatotoxicity caused by vancomycin.

BACKGROUND: Although the correlation between liver toxicity and vancomycin is generally considered low, it has been observed that the use of vancomycin can lead to abnormal liver function indicators, such as elevated aspartate aminotransferase, alanine aminotransferase, alpha fetoprotein, and jaundice. To further understand the clinical features associated with vancomycin-induced liver toxicity and to provide clinical guidance, we conducted an analysis of the characteristics and clinical manifestations of vancomycin-induced liver injury. METHODS: Patients with liver function injury who received vancomycin treatment at the Third Xiangya Hospital of Central South University and Hunan Maternal and Child Health Hospital between 2016 and 2021 were selected for retrospective analysis of their general characteristics, vancomycin course, dose, liver function index, severity of liver injury, and concomitant medications. RESULTS: Of the 4562 patients who received vancomycin, 17 patients were finally included, with an incidence rate of 0.37%. Of these patients, 12 were male (70.6%) and 5 were female (29.4%), ranging in age from 17 to 84 years with a mean average age of 45.41 ± 20.405 years. All patients were evaluated using Naranjo's score, with score ≥ 3. The dosage, time, and plasma concentration of vancomycin were analyzed and it was found that nine patients (52.94%) had abnormal liver function when initially given a dose of 1 g every 12 hours. In total, 14 patients (82.35%) with liver injury were taking vancomycin in combination with two to four drugs, and severe liver injury occurred in patients taking vancomycin in combination with two drugs. The occurrence time of liver injury was 2-12 days after starting vancomycin, with a mean of 4.53 ± 2.401 days. Of these patients, 16 patients (94.1%) showed liver function abnormalities within 7 days of taking the drug, and 2 patients with grade 3-4 liver injury both showed liver function abnormalities within 3 days of taking the drug. Only 4 of the 17 patients (23.53%) had vancomycin blood concentrations within the normal range, and there was no correlation found between blood concentration and severity of liver injury. Analysis of the correlation between the severity of liver injury and vancomycin showed that none of the patients had allergies such as rash, two patients (11.76%) had jaundice, and fatigue occurred in five patients (29.41%). The remaining ten patients (58.82%) had no symptoms related to liver injury. All 17 patients had abnormal aspartate aminotransferase/alanine aminotransferase levels and 9 patients also had abnormal bilirubin levels. In 15 patients (88.24%), the severity of liver injury was grade 1, indicating mild liver injury, and no correlation was observed between the severity of liver injury and creatinine. Of the 17 patients, 1 patient received no intervention, 4 patients stopped taking vancomycin after developing liver injury, 1 patient reduced the dose, and 11 patients (64.7%) were treated with hepatic protectant. CONCLUSION: Although the study concluded that the incidence of liver injury was not high, the liver toxicity of vancomycin should still be considered and liver function indicators should be monitored during the clinical use of vancomycin.

Innovative Vancomycin-Loaded Hydrogel-Based Systems - New Opportunities for the Antibiotic Therapy.

Purpose: Surgical site infections pose a significant challenge for medical services. Systemic antibiotics may be insufficient in preventing bacterial biofilm development. With the local administration of antibiotics, it is easier to minimize possible complications, achieve drugs' higher concentration at the injured site, as well as provide their more sustained release. Therefore, the main objective of the proposed herein studies was the fabrication and characterization of innovative hydrogel-based composites for local vancomycin (VAN) therapy. Methods: Presented systems are composed of ionically gelled chitosan particles loaded with vancomycin, embedded into biomimetic collagen/chitosan/hyaluronic acid-based hydrogels crosslinked with genipin and freeze-dried to serve in a flake/disc-like form. VAN-loaded carriers were characterized for their size, stability, and encapsulation efficiency (EE) using dynamic light scattering technique, zeta potential measurements, and UV-Vis spectroscopy, respectively. The synthesized composites were tested in terms of their physicochemical and biological features. Results: Spherical structures with sizes of about 200 nm and encapsulation efficiencies reaching values of approximately 60% were obtained. It was found that the resulting particles exhibit stability over time. The antibacterial activity of the developed materials against Staphylococcus aureus was established. Moreover, in vitro cell culture study revealed that the surfaces of all prepared systems are biocompatible as they supported the proliferation and adhesion of the model MG-63 cells. In addition, we have demonstrated significantly prolonged VAN release while minimizing the initial burst effect for the composites compared to bare nanoparticles and verified their desired physicochemical features during swellability, and degradation experiments. Conclusion: It is expected that the developed herein system will enable direct delivery of the antibiotic at an exposed to infections surgical site, providing drugs sustained release and thus will reduce the risk of systemic toxicity. This strategy would both inhibit biofilm formation and accelerate the healing process.

A sandwich-structured multifunctional platform based on self-assembled Ti3C2Tx@Au NPs films, antibiotics, and silent region SERS probe for the capture, determination, and drug resistance analysis of Gram-positive bacteria.

A multifunctional surface-enhanced Raman scattering (SERS) platform integrating sensitive detection and drug resistance analysis was developed for Gram-positive bacteria. The substrate was based on self-assembled Ti3C2Tx@Au NPs films and capture molecule phytic acid (IP6) to achieve specific capture of Gram-positive bacteria and different bacteria were analyzed by fingerprint signal. It had advantages of good stability and homogeneity (RSD = 8.88%). The detection limit (LOD) was 102 CFU/mL for Staphylococcus aureus and 103 CFU/mL for MRSA, respectively. A sandwich structure was formed on the capture substrate by signal labels prepared by antibiotics (penicillin G and vancomycin) and non-interference SERS probe molecules (4-mercaptobenzonitrile (2223 cm-1) and 2-amino-4-cyanopyridine (2240 cm-1)) to improve sensitivity. The LOD of Au NPs@4-MBN@PG to S. aureus and Au NPs@AMCP@Van to MRSA and S. aureus were all improved to 10 CFU/mL, with a wide dynamic linear range from 108 to 10 CFU/mL (R2 ≥ 0.992). The SERS platform can analyze the drug resistance of drug-resistant bacteria. Au NPs@4-MBN@PG was added to the substrate and captured MRSA to compare the SERS spectra of 4-MBN. The intensity inhomogeneity of 4-MBN at the same concentrations of MRSA and the nonlinearity at the different concentrations of MRSA revealed that MRSA was resistant to PG. Finally, the SERS platform achieved the determination of MRSA in blood. Therefore, this SERS platform has great significance for the determination and analysis of Gram-positive bacteria.

A fluorescent sensor array based on antibiotic-stabilized metal nanoclusters for the multiplex detection of bacteria.

To address the need for facile, rapid detection of pathogens in water supplies, a fluorescent sensing array platform based on antibiotic-stabilized metal nanoclusters was developed for the multiplex detection of pathogens. Using five common antibiotics, eight different nanoclusters (NCs) were synthesized including ampicillin stabilized copper NCs, cefepime stabilized gold and copper NCs, kanamycin stabilized gold and copper NCs, lysozyme stabilized gold NCs, and vancomycin stabilized gold/silver and copper NCs. Based on the different interaction of each NC with the bacteria strains, unique patterns were generated. Various machine learning algorithms were employed for pattern discernment, among which the artificial neural networks proved to have the highest performance, with an accuracy of 100%. The developed prediction model performed well on an independent test dataset and on real samples gathered from drinking water, tap water and the Anzali Lagoon water, with prediction accuracy of 96.88% and 95.14%, respectively. This work demonstrates how generic antibiotics can be implemented for NC synthesis and used as recognition elements for pathogen detection. Furthermore, it displays how merging machine learning techniques can elevate sensitivity of analytical devices.

Ultrasensitive and Highly Selective Detection of Staphylococcus aureus at the Single-Cell Level Using Bacteria-Imprinted Polymer and Vancomycin-Conjugated MnO2 Nanozyme.

Pathogenic bacterial infections, even at extremely low concentrations, pose significant threats to human health. However, the challenge persists in achieving high-sensitivity bacterial detection, particularly in complex samples. Herein, we present a novel sandwich-type electrochemical sensor utilizing bacteria-imprinted polymer (BIP) coupled with vancomycin-conjugated MnO2 nanozyme (Van@BSA-MnO2) for the ultrasensitive detection of pathogenic bacteria, exemplified by Staphylococcus aureus (S. aureus). The BIP, in situ prepared on the electrode surface, acts as a highly specific capture probe by replicating the surface features of S. aureus. Vancomycin (Van), known for its affinity to bacterial cell walls, is conjugated with a Bovine serum albumin (BSA)-templated MnO2 nanozyme through EDC/NHS chemistry. The resulting Van@BSA-MnO2 complex, serving as a detection probe, provides an efficient catalytic platform for signal amplification. Upon binding with the captured S. aureus, the Van@BSA-MnO2 complex catalyzes a substrate reaction, generating a current signal proportional to the target bacterial concentration. The sensor displays remarkable sensitivity, capable of detecting a single bacterial cell in a phosphate buffer solution. Even in complex milk matrices, it maintains outstanding performance, identifying S. aureus at concentrations as low as 10 CFU mL-1 without requiring intricate sample pretreatment. Moreover, the sensor demonstrates excellent selectivity, particularly in distinguishing target S. aureus from interfering bacteria of the same genus at concentrations 100-fold higher. This innovative method, employing entirely synthetic materials, provides a versatile and low-cost detection platform for Gram-positive bacteria. In comparison to existing nanozyme-based bacterial sensors with biological recognition materials, our assay offers distinct advantages, including enhanced sensitivity, ease of preparation, and cost-effectiveness, thereby holding significant promise for applications in food safety and environmental monitoring.

Efficacy of Intrawound Vancomycin in Prevention of Periprosthetic Joint Infection After Primary Total Knee Arthroplasty: A Prospective Double-Blinded Randomized Control Trial.

BACKGROUND: Periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is a devastating complication. Intrawound vancomycin powder has been shown to reduce infection rates in spine surgery, but its role in arthroplasty remains controversial. This prospective randomized control trial aimed to evaluate the efficacy of intrawound vancomycin in preventing PJI after primary TKA. METHODS: A total of 1,022 patients were randomized to the study group (n = 507, who received 2 grams intrawound vancomycin powder before arthrotomy closure) or to the control group (n = 515, no local vancomycin) with a minimum follow-up of 12-months. The primary outcome was the incidence of PJI or surgical site infection (SSI). Secondary outcomes included associated minor complications such as stitch abscess, persistent wound drainage, and delayed stitch removal. Other parameters evaluated include reoperation rates and incidences of nephrotoxicity. RESULTS: The overall infection rate in 1,022 patients was 0.66%. There was no significant difference in PJI rate in the study group (N = 1; 0.2%) versus the control group (N = 3; 0.58%), P = .264. Reoperation rates in the study group (N = 4; 0.78%) and control (N = 5; 0.97%), and SSI rates in the study (N = 1; 0.2%) and control groups (N = 2; 0.38%) were comparable. The Vancomycin cohort, however, demonstrated a significantly higher number of minor wound complications (n = 67; 13.2%) compared to the control group (n = 39; 7.56%, P < .05). Subgroup analysis showed diabetics in the study group to also have a higher incidence of minor wound complications (24 [14.1%] versus 10 [6.2%]; P < 05]. Multivariate analyses found that vancomycin use (odds ratio = 1.64) and smoking (odds ratio = 1.85) were associated with an increased risk of developing minor wound complications. No cases of nephrotoxicity were reported. CONCLUSIONS: Intrawound vancomycin powder does not appear to reduce PJI/SSI rate in primary total knee arthroplasties, including high-risk groups. Although safe from a renal perspective, intrawound vancomycin was associated with an increase in postoperative aseptic wound complications. Intrawound vancomycin may not be effective in reducing the rate of PJI in primary TKA.

Determination of vancomycin and meropenem in serum and synovial fluid of patients with prosthetic joint infections using UPLC-MS/MS.

Numerous studies have suggested that intra-articular administration of antibiotics following primary revision surgery may be one of the methods for treating prosthetic joint infection (PJI). Vancomycin and meropenem are the two most commonly used antibiotics for local application. Determining the concentrations of vancomycin and meropenem in the serum and synovial fluid of patients with PJI plays a significant role in further optimizing local medication schemes and effectively eradicating biofilm infections. This study aimed to establish a rapid, sensitive, and accurate ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determining the concentrations of vancomycin and meropenem in human serum and synovial fluid. Serum samples were processed using acetonitrile precipitation of proteins and dichloromethane extraction, while synovial fluid samples were diluted before analysis. Chromatographic separation was achieved in 6 min on a Waters Acquity UPLC BEH C18 column, with the mobile phase consisting of 0.1% formic acid in water (solvent A) and acetonitrile (solvent B). Quantification was carried out using a Waters XEVO TQD triple quadrupole mass spectrometer with an electrospray ionization (ESI) source in positive ion mode. The multiple reaction monitoring (MRM) mode was employed to detect the following quantifier ion transitions: 717.95-99.97 (norvancomycin), 725.90-100.04 (vancomycin), 384.16-67.99 (meropenem). The method validation conformed to the guidelines of the FDA and the Chinese Pharmacopoeia. The method demonstrated good linearity within the range of 0.5-50 µg/ml for serum and 0.5-100 µg/ml for synovial fluid. Selectivity, intra-day and inter-day precision and accuracy, extraction recovery, matrix effect, and stability validation results all met the required standards. This method has been successfully applied in the pharmacokinetic/pharmacodynamic (PK/PD) studies of patients with PJI.

Limb salvage and systemic management of gouty tophi: Case series.

INTRODUCTION: Gout is a chronic disease characterized by deposition of monosodium urate crystals. Tophi develop in some individuals with untreated or uncontrolled gout, which leads to ulcerations, cosmetic problems, mechanical obstruction of joint movement, joint damage and musculoskeletal disability. Currently, the treatment of gouty tophi is controversial and challenging. Both surgical and internal medical treatments have limitations and require further exploration in clinical practice. PATIENT CONCERNS: In Case 1, we treated a patient with severe infection of diabetic foot ulcers with concomitant multiple gouty tophi in the same limb. A systematic management strategy was formulated to close the wound and save the limb. The ulcers healed successfully after half a year. In Case 2, a giant gouty tophi located in the first metatarsophalangeal joint of the left foot was removed by surgical treatment and vancomycin-loaded bone cement implantation. In Case 3, we present a case of gouty tophi that was resolved by standardized systemic medical management. DIAGNOSIS: Three patients were all diagnosed with gout accompanied by gouty deposition, although there were other different comorbidities. INTERVENTIONS: In case 1, we used debridement to gradually remove gouty tophi. In case 2, the giant gouty tophi was removed by surgical operation. In case 3, the gouty tophi disappeared after standardized treatment with medicine, diet and lifestyle management. OUTCOMES: Three patients underwent different treatment therapies to remove gouty tophi based on their specific conditions. LESSONS: We explored effective interventions for tophi in gout by surgical or other interventions in combination with pharmacotherapy.

[Utility of topical vancomycin application in the prevention of surgical site infection of the lumbosacral spine]. / Utilidad de la aplicación de vancomicina tópica en la prevención de infección de sitio quirúrgico de la columna lumbosacra.

INTRODUCTION: surgical site infections (SSI) remain a significant cause of morbidity and mortality and one of the most representative causes of nosocomial infections. The use of intrawound vancomycin in lumbar spine surgery is a potential prophylactic measure against SSI; however, evidence regarding its efficacy is contradictory. Our study was designed to research if intrawound vancomycin significantly prevents SSI in lumbar spine surgery. MATERIAL AND METHODS: this is a randomized, double-blinded, controlled clinical trial; 233 patients who underwent lumbar spine surgery, were randomly assigned to a group in which intrawound vancomycin was instilled in the incision before closure (109), or to a control group (114). The main outcome is the presence of SSI; we determined its prevalence and searched for difference between groups for association between SSI and independent variables. RESULTS: global SSI prevalence was 1.8%, in the experimental group was 0.9%, in the control group was 2.6%. There was no significant difference between these values, p = 0.622. The relative risk of SSI in the experimental group was 0.35 (95% CI 0.037-3.30), that of the control group was 2.87 (95% CI 0.30-27.16). The number needed to treat is 58.3. We did not find a significant association between the independent variables studied and the appearance of SSI. CONCLUSIONS: we did not find a significant difference in the prevalence of SSI between groups nor a significant association between SSI and independent variables.

INTRODUCCIÓN: las infecciones postoperatorias del sitio quirúrgico son una importante causa de morbimortalidad y una de las formas más comunes de infecciones nosocomiales. La aplicación de vancomicina al terminar una intervención de columna lumbar es una potencial práctica profiláctica de infecciones del sitio quirúrgico (ISQ). La evidencia que sostiene su uso es controversial. Nuestro estudio investiga si la aplicación de vancomicina disminuye en forma significativa la prevalencia de ISQ. MATERIAL Y MÉTODOS: ensayo clínico aleatorizado, controlado, cegado; 223 pacientes intervenidos de la columna lumbar fueron aleatoriamente asignados a un grupo experimental de 109 pacientes en quienes se colocó vancomicina y a un grupo control de 114 pacientes que no recibió vancomicina. El principal desenlace del estudio es la aparición de ISQ; se estudió la prevalencia de ISQ en ambos grupos y se buscó si existe diferencia significativa. Se analizó la existencia de factores predictores de ISQ. RESULTADOS: la prevalencia global de infección fue 1.8%; en el grupo experimenta 0.09% y en el grupo control 2.6%. No hubo diferencia significativa entre estas cifras, p = 0.622. El riesgo relativo de ISQ en el grupo experimental fue 0.35 (IC95% 0.037-3.30), el del grupo control fue 2.87 (IC95% 0.30-27.16). El número necesario para tratar es 58.3. No encontramos asociación significativa entre las variables independientes estudiadas y la aparición de ISQ. CONCLUSIONES: no encontramos evidencia suficiente de que la aplicación de vancomicina disminuya significativamente la prevalencia de ISQ ni asociación significativa de ISQ con las variables independientes estudiadas.

Toxin genotypes, antibiotic resistance and their correlations in Clostridioides difficile isolated from hospitals in Xi'an, China.

BACKGROUND: Clostridioides difficile is the main pathogen of antimicrobial-associated diarrhoea and health care facility-associated infectious diarrhoea. This study aimed to investigate the prevalence, toxin genotypes, and antibiotic resistance of C. difficile among hospitalized patients in Xi'an, China. RESULTS: We isolated and cultured 156 strains of C. difficile, representing 12.67% of the 1231 inpatient stool samples collected. Among the isolates, tcdA + B + strains were predominant, accounting for 78.2% (122/156), followed by 27 tcdA-B + strains (27/156, 17.3%) and 6 binary toxin gene-positive strains. The positive rates of three regulatory genes, tcdC, tcdR, and tcdE, were 89.1% (139/156), 96.8% (151/156), and 100%, respectively. All isolates were sensitive to metronidazole, and the resistance rates to clindamycin and cephalosporins were also high. Six strains were found to be resistant to vancomycin. CONCLUSION: Currently, the prevalence rate of C. difficile infection (CDI) in Xi'an is 12.67% (156/1231), with the major toxin genotype of the isolates being tcdA + tcdB + cdtA-/B-. Metronidazole and vancomycin were still effective drugs for the treatment of CDI, but we should pay attention to antibiotic management and epidemiological surveillance of CDI.

Diagnostic value of BHI-V4 for heterogeneous and vancomycin-intermediate Staphylococcus aureus isolates: a systematic review and meta-analysis.

BACKGROUND: Brain-heart infusion agar supplemented with 4 µg/mL of vancomycin (BHI-V4) was commonly used for the detection of heterogeneous (hVISA) and vancomycin-intermediate Staphylococcus aureus (VISA). However, its diagnostic value remains unclear. This study aims to compare the diagnostic accuracy of BHI-V4 with population analysis profiling with area under the curve (PAP-AUC) in hVISA/VISA. METHODS: The protocol of this study was registered in INPLASY (INPLASY2023120069). The PubMed and Cochrane Library databases were searched from inception to October 2023. Review Manager 5.4 was used for data visualization in the quality assessment, and STATA17.0 (MP) was used for statistical analysis. RESULTS: In total, eight publications including 2153 strains were incorporated into the meta-analysis. Significant heterogeneity was evident although a threshold effect was not detected across the eight studies. The summary receiver operating characteristic (SROC) was 0.77 (95% confidence interval [CI], 0.74-0.81). The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic score and diagnostic odds ratio were 0.59 (95% CI: 0.46-0.71), 0.96 (95%CI: 0.83-0.99), 14.0 (95% CI, 3.4-57.1), 0.43 (95%CI, 0.32-0.57), 3.48(95%CI, 2.12-4.85) and 32.62 (95%CI, 8.31-128.36), respectively. CONCLUSION: Our study showed that BHI-V4 had moderate diagnostic accuracy for diagnosing hVISA/VISA. However, more high-quality studies are needed to assess the clinical utility of BHI-V4.

Polymeric membrane potentiometric sensors based on template-removal-free imprinted receptors for determination of antibiotics.

Currently, Nernstian-response-based polymeric membrane potentiometric sensors using molecularly imprinted polymers (MIPs) as receptors have been successfully developed for determination of organic ionic species. However, the preparation of these MIP receptors usually involves tedious and time-consuming template-removal procedures. Herein, a template-removal-free MIP is proposed and used as a receptor for fabrication of a potentiometric sensor. The proposed methodology not only significantly shortens the preparation time of MIP-based potentiometric sensors but also improves the batch-to-batch reproducibility of these sensors. By using antibiotic vancomycin as a model, the new concept offers a linear concentration range of 1.0 × 10-7 to 1.0 × 10-4 mol L-1 with a detection limit of 2.51 × 10-8 mol L-1. It can be expected that the template-removal-free MIP-based sensing strategy could lay the foundation for simple fabrication of electrochemical sensors without the need for template removal such as potentiometric and capacitive sensors and ion-sensitive field-effect transistors.

Identification and characterization of critical values in therapeutic drug monitoring: a retrospective analysis.

Therapeutic drug monitoring (TDM) is a crucial clinical practice that improves pharmacological effectiveness and prevent severe drug-related adverse events. Timely reporting and intervention of critical values during TDM are essential for patient safety. In this study, we retrospectively analyzed the laboratory data to provide an overview of the incidence, distribution pattern and biochemical correlates of critical values during TDM. A total of 19,110 samples were tested for nine drug concentrations between January 1, 2019, and December 31, 2020. Of these, 241 critical values were identified in 165 patients. The most common critical values were vancomycin trough (63.4%), followed by tacrolimus trough (16.9%) and digoxin (15.2%). The primary sources of drug critical values were the department of general intensive care unit (ICU), cardiology, and surgery ICU. At baseline or the time of critical value, significant differences were found between the vancomycin, digoxin, and tacrolimus groups in terms of blood urea nitrogen (BUN), creatinine, N-terminal Pro-B-Type Natriuretic Peptide (NT-proBNP), and lymphocyte percentage, P < 0.05. Therefore, it is important to prioritize and closely monitor drug concentrations to reduce laboratory critical values during TDM.

Cascade-Targeted Nanoplatforms for Synergetic Antibiotic/ROS/NO/Immunotherapy against Intracellular Bacterial Infection.

Intracellular bacteria in dormant states can escape the immune response and tolerate high-dose antibiotic treatment, leading to severe infections. To overcome this challenge, cascade-targeted nanoplatforms that can target macrophages and intracellular bacteria, exhibiting synergetic antibiotic/reactive oxygen species (ROS)/nitric oxide (NO)/immunotherapy, were developed. These nanoplatforms were fabricated by encapsulating trehalose (Tr) and vancomycin (Van) into phosphatidylserine (PS)-coated poly[(4-allylcarbamoylphenylboric acid)-ran-(arginine-methacrylamide)-ran-(N,N'-bisacryloylcystamine)] nanoparticles (PABS), denoted as PTVP. PS on PTVP simulates a signal of "eat me" to macrophages to promote cell uptake (the first-step targeting). After the uptake, the nanoplatform in the acidic phagolysosomes could release Tr, and the exposed phenylboronic acid on the nanoplatform could target bacteria (the second-step targeting). Nanoplatforms can release Van in response to infected intracellular overexpressed glutathione (GSH) and weak acid microenvironment. l-arginine (Arg) on the nanoplatforms could be catalyzed by upregulated inducible nitric oxide synthase (iNOS) in the infected macrophages to generate nitric oxide (NO). N,N'-Bisacryloylcystamine (BAC) on nanoplatforms could deplete GSH, allow the generation of ROS in macrophages, and then upregulate proinflammatory activity, leading to the reinforced antibacterial capacity. This nanoplatform possesses macrophage and bacteria-targeting antibiotic delivery, intracellular ROS, and NO generation, and pro-inflammatory activities (immunotherapy) provides a new strategy for eradicating intracellular bacterial infections.

Comparison of fidaxomicin, thuricin CD, vancomycin and nisin highlights the narrow spectrum nature of thuricin CD.

Vancomycin and metronidazole are commonly used treatments for Clostridioides difficile infection (CDI). However, these antibiotics have been associated with high levels of relapse in patients. Fidaxomicin is a new treatment for CDI that is described as a narrow spectrum antibiotic that is minimally active on the commensal bacteria of the gut microbiome. The aim of this study was to compare the effect of fidaxomicin on the human gut microbiome with a number of narrow (thuricin CD) and broad spectrum (vancomycin and nisin) antimicrobials. The spectrum of activity of each antimicrobial was tested against 47 bacterial strains by well-diffusion assay. Minimum inhibitory concentrations (MICs) were calculated against a select number of these strains. Further, a pooled fecal slurry of 6 donors was prepared and incubated for 24 h with 100 µM of each antimicrobial in a mini-fermentation system together with a no-treatment control. Fidaxomicin, vancomycin, and nisin were active against most gram positive bacteria tested in vitro, although fidaxomicin and vancomycin produced larger zones of inhibition compared to nisin. In contrast, the antimicrobial activity of thuricin CD was specific to C. difficile and some Bacillus spp. The MICs showed similar results. Thuricin CD exhibited low MICs (<3.1 µg/mL) for C. difficile and Bacillus firmus, whereas fidaxomicin, vancomycin, and nisin demonstrated lower MICs for all other strains tested when compared to thuricin CD. The narrow spectrum of thuricin CD was also observed in the gut model system. We conclude that the spectrum of activity of fidaxomicin is comparable to that of the broad-spectrum antibiotic vancomycin in vitro and the broad spectrum bacteriocin nisin in a complex community.

Antibiotic calcium sulphate beads lower the bacterial burden and prevent infection in a mouse model of periprosthetic joint infection.

Aims: Delayed postoperative inoculation of orthopaedic implants with persistent wound drainage or bacterial seeding of a haematoma can result in periprosthetic joint infection (PJI). The aim of this in vivo study was to compare the efficacy of vancomycin powder with vancomycin-eluting calcium sulphate beads in preventing PJI due to delayed inoculation. Methods: A mouse model of PJI of the knee was used. Mice were randomized into groups with intervention at the time of surgery (postoperative day (POD) 0): a sterile control (SC; n = 6); infected control (IC; n = 15); systemic vancomycin (SV; n = 9); vancomycin powder (VP; n = 21); and vancomycin bead (VB; n = 19) groups. Delayed inoculation was introduced during an arthrotomy on POD 7 with 1 × 105 colony-forming units (CFUs) of a bioluminescent strain of Staphylococcus aureus. The bacterial burden was monitored using bioluminescence in vivo. All mice were killed on POD 21. Implants and soft-tissue were harvested and sonicated for analysis of the CFUs. Results: The mean in vivo bioluminescence in the VB group was significantly lower on POD 8 and POD 10 compared with the other groups. There was a significant 1.3-log10 (95%) and 1.5-log10 (97%) reduction in mean soft-tissue CFUs in the VB group compared with the VP and IC groups (3.6 × 103 vs 7.0 × 104; p = 0.022; 3.6 × 103 vs 1.0 × 105; p = 0.007, respectively) at POD 21. There was a significant 1.6-log10 (98%) reduction in mean implant CFUs in the VB group compared with the IC group (1.3 × 100 vs 4.7 × 101, respectively; p = 0.038). Combined soft-tissue and implant infection was prevented in 10 of 19 mice (53%) in the VB group as opposed to 5 of 21 (24%) in the VP group, 3 of 15 (20%) in the IC group, and 0% in the SV group. Conclusion: In our in vivo mouse model, antibiotic-releasing calcium sulphate beads appeared to outperform vancomycin powder alone in lowering the bacterial burden and preventing soft-tissue and implant infections.

Synthetic antimicrobial peptides: activity against vancomycin-resistant Enterococcus faecalis and modulation of chloramphenicol antibacterial activity.

AIMS: Enterococcus faecalis (E. faecalis) is a leading cause of nosocomial infection and presents a wide spectrum of antibiotic resistance, being vancomycin-resistant Enterococcus (VRE) one of the most relevant. Synthetic antimicrobial peptides (SAMPs) are currently a promising option to overcome antimicrobial resistance. Thus, the purpose of this study was to assess the effect of eight SAMPs against vancomycin-resistant E. faecalis, as well as to investigate their mechanism of action and synergy with conventional antibiotics. METHODS AND RESULTS: Here, eight SAMPs, Mo-CBP3-PepI, Mo-CBP3-PepII, Mo-CBP3-PepIII, RcAlb-PepI, RcAlb-PepII, RcAlb-PepIII, PepGAT, and PepKAA, were tested for antibacterial activity in vitro against E. faecalis (ATCC® 51299) through broth microdilution. A maximum of 48% of E. faecalis growth inhibition was achieved by treatment with SAMPs alone. However, when these peptides were combined with the antibiotic chloramphenicol, assessed by checkerboard method, the inhibition increased to 55%-76% of inhibition, two to three-folds of increase if compared to the effects of the compounds alone. Microscopic analysis showed that E. faecalis cells treated with a combination of SAMPs and chloramphenicol resulted in bacterial membrane damage. The biofilm inhibition maximum was 22% for SAMPs alone, when combined with chloramphenicol, the maximum increased to 33%. CONCLUSIONS: SAMPs and their combination with chloramphenicol demonstrate antibacterial activity against E. faecalis, possibly by inducing bacterial membrane damage.

Presoaking Grafts in Vancomycin Does Not Impair Graft-Bone Healing in a Rat Anterior Cruciate Ligament Reconstruction Model.

BACKGROUND: The vancomycin presoaking technique (wherein grafts are treated with a vancomycin solution [VS] for anterior cruciate ligament reconstruction [ACLR]) reduces the infection rate after ACLR. However, the effects of this technique on graft-bone healing have not been fully elucidated. PURPOSE: To investigate the effects of vancomycin presoaking on graft-bone healing in a rat ACLR model. STUDY DESIGN: Controlled laboratory study. METHODS: Long flexor digitorum longus tendons were obtained from 9 Wistar rats, and each was randomly allocated to the normal saline (NS) or VS groups. The grafts were immersed in sterile saline for 30 minutes in the NS group and in a 5-mg/mL VS in the VS group. The presence of time-zero graft bacterial contamination was confirmed, and the grafts were incubated in Fluidised Thioglycollate Broth for 2 weeks. ACLR was performed on the right knees of 65 male Wistar rats using the flexor digitorum longus tendons. Each graft was similarly treated. Biomechanical testing, micro-computed tomography, and histological evaluations were performed 4 and 12 weeks postoperatively. RESULTS: The VS group showed significantly reduced graft contamination at time zero (P = .02). The mean maximum loads to failure were 13.7 ± 8.2 N and 11.6 ± 4.8 N in the NS and VS groups, respectively, at 4 weeks (P = .95); and 23.2 ± 13.2 N and 30.4 ± 18.0 N in the NS and VS groups, respectively, at 12 weeks (P = .35). Regarding micro-computed tomography, the mean bone tunnel volumes were 3.76 ± 0.48 mm3 and 4.40 ± 0.58 mm3 in the NS and VS groups, respectively, at 4 weeks (P = .41); and 3.51 ± 0.38 mm3 and 3.67 ± 0.35 mm3 in the NS and VS groups, respectively, at 12 weeks (P = .54). Histological semiquantitative examination revealed no clear between-group differences at any time point. CONCLUSION: Presoaking grafts in vancomycin in a rat ACLR model demonstrated no discernible adverse effects on short- and midterm biomechanical, radiological, and histological investigations. CLINICAL RELEVANCE: The findings provide guidance for surgeons when considering this technique.

Detoxification of vancomycin fermentation residue by hydrothermal treatment and pyrolysis: Chemical analysis and toxicity tests.

Vancomycin fermentation residue (VFR) is a by-product of the pharmaceutical industry with high ecotoxicity caused by the residual antibiotics, antibiotic resistance genes (ARGs), and heavy metals (HMs). In this study, the detoxification effect of hydrothermal treatment (HT) and pyrolysis for VFR was assessed using chemical analysis and toxicity tests. When VFR was subjected to HT and pyrolysis at ≥400 °C, more than 99.70 % of the residual vancomycin and all ARGs were removed. The HMs contents in VFR followed the order of manganese (676.2 mg/kg) > zinc (148.6 mg/kg) > chromium (25.40 mg/kg) > copper (17.20 mg/kg), and they were highly bioavailable and easily leached. However, HT and pyrolysis (≥400 °C) substantially reduced the bioavailable fractions and leaching properties of the HMs. After HT and pyrolysis at ≥ 400 °C, the potential ecological risk of HMs in VFR was reduced from considerable to moderate/low levels. The elutriate acute toxicity test suggested that HT and pyrolysis at ≥ 400 °C effectively reduced the toxicity of VFR to an acceptable level (p < 0.05). This study demonstrates that HT and pyrolysis (≥400 °C) are promising methods for treating VFR and detoxifying it, and the treated products are safe for further reutilization.

Endogenous Endophthalmitis from Urinary Tract Infection Caused by Group B Streptococcus: A Case Report.

We present a case of endogenous endophthalmitis with urinary tract infection (UTI) caused by group B Streptococcus (GBS). An 86-year-old female initially presented with ocular pain and sudden visual disturbance of the left eye. The patient did not complain of other symptoms and had no history of recent ocular surgery or trauma. Endogenous endophthalmitis was clinically diagnosed based on ophthalmic examination, history, and lab results showing systemic infection. A few days later, GBS was identified in her aqueous humor, blood, and urine cultures. Intravitreal ceftazidime and vancomycin injections, as well as fortified ceftazidime and vancomycin eye drops, were used immediately after clinical diagnosis. However, the symptoms worsened despite repeated intravitreal injections, so evisceration was performed. Endogenous endophthalmitis caused by GBS is very virulent and may present without evident systemic symptoms. The early recognition of the disease and systemic work up, followed by prompt treatment, is necessary.