Antibacterial Activity of Surfactin and Synergistic Effect with Conventional Antibiotics Against Methicillin-Resistant Staphylococcus aureus Isolated from Patients with Diabetic Foot Ulcers.

Introduction: The prevalence of diabetic foot ulcers (DFUs) is increasing, leading to a huge financial burden and human suffering. Furthermore, antibiotic resistance is an urgent problem in the realm of clinical practice. Antimicrobial peptides are an effective and feasible strategy for combating infections caused by drug-resistant bacteria. Therefore, we investigated the in vitro antimicrobial ability of the lipopeptide surfactin, either alone or in combination with conventional antibiotics, against the standard and clinical strains of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), isolated from patients with DFUs. Methods: The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of surfactin on the selected strains were evaluated by a microbroth dilution technique. The growth curves of the selected strains with and without surfactin were measured, and transmission electron microscopy was used to observe the structure of surfactin-treated bacterial cells. The biofilm inhibitory abilities of surfactin were assessed by crystal violet staining. The antimicrobial interactions between surfactin and conventional antibiotics were established using a checkerboard assay, as well as determining the mutant prevention concentration. The inhibitory effect of surfactin on penicillinase was tested by iodometry. Results: The MIC and MBC values of surfactin ranged from 512 to 1024 µg/mL and 1024 to 2048 µg/mL, respectively. Moreover, surfactin significantly prevented the S. aureus biofilm formation and displayed limited toxicity on human red blood cells. The synergies between surfactin and ampicillin, oxacillin, and tetracycline against S. aureus were revealed. In vitro resistance was not readily produced by surfactin. The action of surfactin may be by disrupting bacterial cell membranes and inhibiting penicillinase. Conclusion: Surfactin appears to be a potential option for the treatment of DFUs infected with MRSA, as it is capable of improving antimicrobial activities and can be used alone or in combination with conventional antibiotics to prevent or postpone the emergence of resistance.

Risk Factors, Outcomes, and Predictions of Extensively Drug-Resistant Acinetobacter baumannii Nosocomial Infections in Patients with Nervous System Diseases.

Purpose: Acinetobacter baumannii has evolved to become a major pathogen of nosocomial infections, resulting in increased morbidity and mortality. This study aimed to investigate the risk factors, outcomes, and predictions of extensively drug-resistant (XDR)-A. baumannii nosocomial infections in patients with nervous system diseases (NSDs). Methods: A retrospective study of patients infected with XDR-A. baumannii admitted to the Affiliated Hospital of Southwest Medical University (Luzhou, China) from January 2021 to December 2022 was conducted. Three multivariate regression models were used to assess the risk factors and predictive value for specific diagnostic and prognostic subgroups. Results: A total of 190 patients were included, of which 84 were diagnosed with NSDs and 80% of those were due to stroke. The overall rates of all-cause mortality for XDR-A. baumannii nosocomial infections and those in NSDs were 38.9% and 40.5%, respectively. Firstly, hypertension, indwelling gastric tube, tracheotomy, deep puncture, bladder irrigation, and pulmonary infections were independent risk factors for XDR-A. baumannii nosocomial infections in patients with NSDs. Moreover, pulmonary infections, the aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio, and the neutrophil-to-lymphocyte ratio (NLR) were significantly associated with increased mortality rates in patients with nosocomial infections caused by XDR-A. baumannii. Thirdly, NLR and cardiovascular diseases accounted for a high risk of mortality for XDR-A. baumannii nosocomial infections in patients with NSDs. The area under the curves of results from each multivariate regression model were 0.827, 0.811, and 0.853, respectively. Conclusion: This study reveals the risk factors of XDR-A. baumannii nosocomial infections in patients with NSDs, and proves their reliable predictive value. Early recognition of patients at high risk, sterilizing medical tools, and regular blood monitoring are all critical aspects for minimizing the nosocomial spread and mortality of A. baumannii infections.

Cigarette Smoking and Peripheral Vascular Disease are Associated with Increasing Risk of ESKAPE Pathogen Infection in Diabetic Foot Ulcers.

Objective: Diabetic foot ulcers (DFUs) and ESKAPE pathogens have attracted attention globally, but the role of ESKAPE pathogens in diabetic foot infection is not well described. The purpose of this study was to evaluate the clinical features, antimicrobial resistance, and risk factors for ESKAPE infection in patients with DFUs. Methods: A retrospective study was conducted on 180 patients with diabetic foot infection admitted to The Affiliated Hospital of Southwest Medical University (Luzhou, China), from January 2017 to April 2021. Antimicrobial susceptibilities of all isolates were determined. Multivariate logistic regression analysis was performed to analyze the independent risk factors for ESKAPE infection, multidrug-resistant (MDR)-ESKAPE infection, MDR-pathogen infection, and severe group in patients with DFUs. Results: A total of 206 isolates were collected, of which 42.2% were ESKAPE pathogens. The independent risk factors for ESKAPE infection were cigarette smoking (OR = 1.958; 95% CI, 1.015-3.777) and peripheral vascular disease (OR = 2.096; 95% CI, 1.100-3.992), while alcohol consumption (OR = 2.172; 95% CI, 1.104-4.272) was the independent risk factor for MDR-pathogen infection. Additionally, the independent risk factors for severe DFU group were invasive treatment (OR = 326.642; 95% CI, 76.644-1392.08), the duration of systemic antibiotic treatment (OR = 0.918; 95% CI, 0.849-0.992), and length of hospital stay (OR = 1.145; 95% CI, 1.043-1.256). No independent risk factors for MDR-ESKAPE infection were found. Conclusion: Our data established the microbiological features of ESKAPE pathogens and clinical manifestations of diabetic foot infection, and provide support for monitoring and management of ESKAPE infection in patients with DFUs in southwest China.

Effect of particle size on adsorption of norfloxacin and tetracycline onto suspended particulate matter in lake.

Aquatic systems are important sinks of antibiotics; however, their final destination has not been completely elucidated. Therefore, we investigated the adsorption behaviors of suspended particulate matter (SPM) in lakes to support the analysis of the migration and transformation of antibiotics in lacustrine environments. SPM was collected from Meiliang Bay (ML) and Gonghu Bay (GH) in Lake Taihu, China, which was sieved into four particle sizes of >300, 150-300, 63-150, and <63 µm for subsequent antibiotic adsorption experiments. All particles exhibited rapid and substantial adsorption of tetracycline and norfloxacin. Most size fractions fit a Langmuir model, indicative of monomolecular adsorption, except the <63-µm fraction, which fit a Freundlich model. Particle size had a substantial influence on antibiotic adsorption; the 63-150-µm fraction had the greatest adsorption capacity, while the >300-µm fraction had the lowest capacity. The influence of particle size on adsorption was mainly related to SPM physicochemical properties, such as cation exchange capacity, surface area, and organic matter content, rather than types of functional groups. Considering the mass ratios, the <63-µm fraction had the greatest contribution to adsorption. Antibiotics adsorbed onto the SPM from ML and GH exhibited different behaviors. The ML SPM settled more readily into sediment, and larger, denser particles were more resistant to resuspension. Conversely, the GH SPM was more likely to be found in the water column, and larger, less-dense particles remained in the water column. These results help improve our understanding of the interactions between SPM and antibiotics in aquatic systems.

Medical students' intentions to seek abortion training and to provide abortion services in future practice.

OBJECTIVES: Lack of providers is a barrier to accessing abortion in Canada. The factors influencing the number of abortion providers are poorly understood. In this study, we assessed the attitudes and intentions of medical students towards abortion training and provision to gain insight into the future supply of abortion providers. METHODS: We surveyed first, second, and third year medical students at an Ontario university to determine their intentions to train in and provide abortion services during different stages of training and in future practice. We assessed students' attitudes and intentions towards training in and providing abortions, their perceptions of social support, their perceived ability to receive training in and to provide abortion services, and their attitudes towards the legality of abortion. RESULTS: Surveys were completed by 337 of 508 potential respondents (66.7%). The responses indicated that the students in the survey held relatively positive attitudes towards the legality and availability of abortion in Canada. Respondents had significantly more positive attitudes towards first trimester medical abortions (and a greater intention to provide them) than towards second trimester surgical abortions. Thirty-five percent of students planned to enter a specialty in which they could perform abortions, but fewer than 30% of these students planned to provide any type of abortion. Intentions to provide abortions were correlated with positive attitudes toward abortion in general and greater perceived social support for abortion provision. CONCLUSION: A small proportion of students sampled intended both to enter a specialty in which abortion would be within the scope of practice and to provide abortion services. Lack of perceived social support for providing abortions and the perceived inability to obtain abortion training or to logistically provide abortions were identified as two potentially modifiable barriers to abortion provision. We propose increasing education on abortion provision and creating policies to promote medical abortion as a method of improving access to abortion across Canada.

Objectifs : Au Canada, l'accès à des services d'avortement est entravé par le manque de fournisseurs de soins étant en mesure d'offrir de tels services. Les facteurs qui influencent le nombre de fournisseurs de services d'avortement sont mal compris. Dans le cadre de cette étude, nous avons évalué les attitudes et les intentions des étudiants de médecine en ce qui concerne la formation en matière d'avortement et l'offre de tels services dans le cadre de leur future pratique, et ce, pour en connaître davantage au sujet de nos futurs effectifs dans ce domaine. Méthodes : Nous avons sondé les étudiants de médecine de première, de deuxième et de troisième année d'une université ontarienne, à différents stades de leur formation (et en leur demandant de remplir un questionnaire traitant de la future pratique qu'ils envisageaient), en vue de déterminer leurs intentions en ce qui concerne l'obtention d'une formation en matière d'avortement et l'offre de services d'avortement. Nous avons évalué les attitudes et les intentions de ces étudiants en ce qui concerne l'obtention d'une formation en matière d'avortement et l'offre de services d'avortement, leurs perceptions en ce qui a trait au soutien social, leur capacité subjective de recevoir une formation en matière d'avortement et d'offrir des services d'avortement, et leurs attitudes envers la légalité de l'avortement. Résultats : Trois cent trente-sept des 508 répondants potentiels (66,7 %) ont répondu aux questionnaires. Les réponses indiquent que les répondants adoptaient des attitudes relativement positives envers la légalité et la disponibilité de l'avortement au Canada. Les répondants adoptaient des attitudes considérablement plus positives envers les avortements médicaux au premier trimestre (et un plus grand nombre d'entre eux avaient l'intention d'offrir de tels services) qu'envers les avortements chirurgicaux menés au deuxième trimestre. Trente-cinq pour cent des étudiants avaient l'intention de choisir une spécialité dans le cadre de laquelle latenue d'avortements serait possible; toutefois, moins de 30 % de ces étudiants avaient l'intention d'offrir quelque type de services d'avortement que ce soit. Les intentions d'offrir des services d'avortement étaient en corrélation avec les attitudes positives envers l'avortement en général et avec la perception d'un soutien social accru envers l'offre de services d'avortement. Conclusion : Une faible proportion de l'échantillon d'étudiants analysé avait l'intention de choisir une spécialité dont le champ d'activité englobe la tenue d'avortements et d'offrir des services d'avortement. L'absence subjective de soutien social envers l'offre de services d'avortement et l'incapacité subjective d'obtenir une formation en matière d'avortement ou d'offrir des services d'avortement au plan logistique ont été identifiés comme étant deux obstacles potentiellement modifiables pour ce qui est de l'offre de services d'avortement. Pour assurer l'amélioration de l'accès à l'avortement d'un bout à l'autre du Canada, nous proposons l'augmentation des efforts d'éducation au sujet de l'offre de services d'avortement et la création de politiques visant la promotion de l'avortement médical.

Developing a model of chronic subdural hematoma.

Chronic subdural hematoma (CSDH) is a common neurosurgical condition that has a high incidence in the increasing elderly population of many countries. Pathologically, it is defined as a persistent liquefied hematoma in the subdural space more than 3 weeks old that is generally encased by a membraneous capsule. CSDHs likely originate after minor head trauma, with a key factor in its development being the potential for a subdural cavity to permit its expansion within, which is usually due to craniocerebral disproportion. The pathogenesis of CSDH has been attributed to osmotic or oncotic pressure differences, although measurements of these factors in the CSDH fluid do not support this theory. Current belief is that CSDH arises from recurrent bleeding in the subdural space, caused by a cycle of local angiogenesis, inflammation, coagulation and ongoing fibrinolysis. However, because of a lack of detailed knowledge about the precise mechanisms, treatment is often limited to surgical interventions that are invasive and often prone to recurrence. Thus, it is possible that an easily reproducible and representative animal model of CSDH would facilitate research in the pathogenesis of CSDH and aid with development of treatment options.