Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising

BACKGROUND: Post-sternotomy mediastinitis (PSM) is a devastating surgical complication affecting 1–3% of patients that undergo cardiac surgery. Staphylococcus aureus is one of the most commonly encountered bacterial pathogen cultured from mediastinal samples obtained from patients with PSM. A component of the membrane of the gram positive bacteria, lipoteichoic acid, stimulates the blood monocytes and macrophages to secrete cytokines, radicals and nitrogen species leading to oxido-inflammatory damage. This seems to be responsible for the high mortality rate in PSM. For the evaluation of the pathogenesis of infection or for the investigation of alternative treatment models in infection, no standard model of mediastinitis seems to be available. In this study, we evaluated four mediastinitis models in rats. METHODS: The rats were divided into four groups to form different infection models. Group A: A suspension of 1 × 10(7 )colony-forming units Staphylococcus aureus in 0,5 mL was inoculated from the right second intercostal space into the mediastinum. Group B: A hole was created in the right second intercostal space and a piece of stainless-steel implant with a length of 0.5 cm was inserted into the mediastinum and a suspension of 1 × 10(7 )cfu bacteria in 0,5 mL was administered via the tail vein. Group C: Precolonized stainless-steel implant was inserted into the mediastinum. Group D: Precolonized stainless-steel implant was inserted into the mediastinum and the bacteria suspension was also injected into the mediastinum. On the 10(th )day, rats were sacrificed and the extension of infection in the mediastenae was evaluated by quantitative cultures. Myeloperoxidase activity (MPO) and malondialdehyde (MDA) levels were determined in the sera to evaluate the neutrophil activation and assess the inflammatory oxidation. RESULTS: The degree of infection in group C and D were 83.3% and 100% respectively (P < 0.001). MDA levels were significantly higher in these two groups than the others (P < 0.001). CONCLUSION: Infected implants and high bacterial concentration administration were the two important components that played a significant role in the outcome of a successful infection in mediastinum in a rat model

How Dialysis Patients Cope with a Curfew? A Comparison of Psychological Status between Hemodialysis and Peritoneal Dialysis Patients During the COVID-19 Pandemic

Introduction: There are many differences between hemodialysis (HD) and peritoneal dialysis (PD) treatments, including their impact on the psychological status of the patients. In this study, our aim was to compare the psychological statuses of HD and PD patients during the social isolation period due to the COVID-19 pandemic. Methods: We conducted this cross-sectional study on adult HD and PD patients when the curfew measures were in effect. We used an electronic form composed of 3 sections to collect data. In the first section, we collected data on the demographics and clinical and laboratory parameters of the patients. The second and third sections consisted of the Hospital Anxiety and Depression Scale (HADS) and the Impact of Event Scale-Revised (IES-R) questionnaires, respectively. Results: The HD (n = 116) and PD (n = 130) groups were similar regarding age and sex, and they had similar HADS anxiety scores. HADS depression scores were higher in PD patients (p = 0.052). IES-R scores were significantly higher in PD patients in comparison to HD patients (p = 0.001). Frequencies of abnormal HADS-anxiety (p = 0.035) and severe psychological impact (p = 0.001) were significantly higher in PD patients. Discussion/Conclusion: During the social isolation period due to the COVID-19 pandemic, HD patients had better mood profiles than PD patients. A more stable daily routine, an uninterrupted face-to-face contact with health-care workers, and social support among patients in the in-center dialysis environment might be the cause of the favorable mood status. PD patients might need additional psychological support during those periods