The inhibition of Staphylococcus epidermidis biofilm formation by vancomycin-modified titanium alloy and implications for the treatment of periprosthetic infection

Peri-prosthetic infections are notoriously difficult to treat as the biomaterial implant is ideal for bacterial adhesion and biofilm formation, resulting in decreased antibiotic sensitivity. Previously, we reported that vancomycin covalently attached to a Ti alloy surface (Vanc-Ti) could prevent bacterial colonization. Herein we examine the effect of this Vanc-Ti surface on Staphylococci epidermidis, a Gram-positive organism prevalent in orthopaedic infections. By direct colony counting and fluorescent visualization of live bacteria, S. epidermidis colonization was significantly inhibited on Vanc-Ti implants. In contrast, the gram-negative organism Escherichia coli readily colonized the Vanc-Ti rod, suggesting retention of antibiotic specificity. By histochemical and SEM analysis, Vanc-Ti prevented S. epidermidis biofilm formation, even in the presence of serum. Furthermore, when challenged multiple times with S. epidermidis, Vanc-Ti rods resisted bacterial colonization. Finally, when S. epidermidis was continuously cultured in the presence of Vanc-Ti, the bacteria maintained a Vanc sensitivity equivalent to the parent strain. These findings indicate that antibiotic derivatization of implants can result in a surface that can resist bacterial colonization. This technology holds great promise for the prevention and treatment of periprosthetic infections.     

Functional MRI of sleep spindles and K-complexes

ObjectiveSleep spindles and K-complexes are EEG hallmarks of non-REM sleep. However, the brain regions generating these discharges and the functional connections of their generators to other regions are not fully known. We investigated the neuroanatomical correlates of spindles and K-complexes using simultaneous EEG and fMRI.MethodsEEGs recorded during EEG-fMRI studies of 7 individuals were used for fMRI analysis. Higher-level group analyses were performed, and images were thresholded at Z ? 2.3.ResultsfMRI of 106 spindles and 60 K-complexes was analyzed. Spindles corresponded to increased signal in thalami and posterior cingulate, and right precuneus, putamen, paracentral cortex, and temporal lobe. K-complexes corresponded to increased signal in thalami, superior temporal lobes, paracentral gyri, and medial regions of the occipital, parietal and frontal lobes. Neither corresponded to regions of decreased signal.ConclusionsfMRI of both spindles and K-complexes depicts signal subjacent to the vertex, which likely indicates each discharges’ source. The thalamic signal is consistent with thalamic involvement in sleep homeostasis. The limbic region’s signal is consistent with roles in memory consolidation. Unlike the spindle, the K-complex corresponds to extensive signal in primary sensory cortices.SignificanceIdentification of these active regions contributes to the understanding of sleep networks and the physiology of awareness and memory during sleep.     

Infection Control Rate of Irrigation and Débridement for Periprosthetic Joint Infection

Background  

Irrigation and débridement with retention of prosthesis is commonly performed for periprosthetic joint infection. Infection control is reportedly dependent on timing of irrigation and débridement relative to the index procedure.     

Two-stage Exchange Arthroplasty for Infected Total Knee Arthroplasty: Predictors of Failure

Background  

In North America, a two-stage exchange arthroplasty remains the preferred surgical treatment for chronic periprosthetic joint infection (PJI). Currently, there are no proper indicators that can guide orthopaedic surgeons in patient selection for two-stage exchange or the appropriate conditions in which to reimplant.     

Multimodal pain management after total joint arthroplasty

Adequate postoperative pain control in patients who have undergone total joint arthroplasty allows faster rehabilitation and reduces the rate of postoperative complications. Multimodal pain management involves the introduction of adjunctive pain control methods in an attempt to control pain with less reliance on opioids and fewer side effects. Current research suggests that traditional nonsteroidal anti-inflammatory drugs (NSAIDs) and the associated cyclooxygenase type-2 (COX-2) inhibitors improve pain control in most cases. Nearly all multimodal pain management modalities have a safe side-effect profile when they are added to existing methods. The exception is the administration of DepoDur (extended-release epidural morphine) to elderly or respiratory-compromised patients because of a potential for hypoxia and cardiopulmonary events.     

Evaluation of the Incidence of Chronic Thromboembolic Pulmonary Hypertension 1 Year After First Episode of Acute Pulmonary Embolism: A Cohort Study

Purpose

Chronic thromboembolic pulmonary hypertension (CTEPH) is an important complication after acute pulmonary embolism (PE) with considerable morbidity and mortality. The aim of this study was to estimate the CTEPH incidence in a cohort after the first occurrence of PE.

Methods

We conducted a 1-year follow-up cohort study between 2015 and 2018 to assess the incidence of CTEPH in 474 patients with their first acute episode of PE. For the diagnosis of CTEPH, patients with unexplained persistent dyspnea during follow-up underwent transthoracic echocardiography, right heart catheterization, ventilation-perfusion lung scanning, and CT pulmonary angiography.

Results

Overall, 317 patients were included in the study. The mean age of the patients was 56.5 ± 16 years. One hundred and three patients (32%) had exertional dyspnea at the 1-year follow-up. Patients with evidence of pulmonary hypertension (PH) on echocardiography underwent right heart catheterization. Eleven patients (18%) had no PH (mPAP < 25 mmHg); 47 patients (81%) had mPAP > 25 mmHg. Fifteen patients had PAWP > 15 mmHg, including those with underlying left heart problems or valvular diseases. There were 32 patients with PAH (mPAP > 25 mmHg and PVR > 3 WU) undergoing CTEPH studies; 22 patients (6.9%) had multiple segmental defects suggesting CTEPH on a perfusion scan.

Conclusion

The incidence of CTEPH observed in this study 1 year after the first episode of acute PE was approximately 6.9%. This incidence seems to be high in our population, and diagnostic and therapeutic strategies for the early identification of CTEPH are needed.

     

High infection frequency,low diversity of Leishmania major and first detection of Leishmania turanica in human in northern Iran

Smears of suspected patients infected with zoonotic cutaneous leishmaniasis (ZCL) were stained and examined under a light microscopic observation. DNA of parasites within human ulcers was extracted directly from their smears. Nested PCR was used to amplify a fragment containing the internal transcribed spacers of the ribosomal RNA genes (ITS-rDNA) of Lesihmania parasites in human from Turkemen Sahara located in the northeastern part of Iran. Based on RFLP method by digesting BsuRI restriction enzyme and more precisely sequencing of DNA ITS-rDNA was shown to be species-specific. The infection rates of Leishmania parasites were high with 154 (93.9%) infections out of 164 suspected patients using microscopic observations. Only from 128 suspected patients out of 164, ITS-rDNA fragments were amplified and 125 samples had enough DNA to digest BsuRI restriction enzyme and do DNA sequencing. The Nested PCR assays detected not only Leishmania major but also Leishmania turanica for the first time, another parasite of the great gerbil in human. The density of L. major was high but the diversity was low with only 2 haplotypes. The overall ratio of L. major (123 infections) to L. turanica (2 infections) was significantly higher (Chi-squared test: p < 0.05). Infections of L. turanica are not reported only and/or not known to cause human disease. Our analytical framework conveys a clear understanding of both L. major and L. turanica which can only be approved as causative agents of ZCL by more extensive sampling and followed by standardized molecular diagnosis.