Activity of biogenic silver nanoparticles in planktonic and biofilm-associated Corynebacterium pseudotuberculosis

Corynebacterium pseudotuberculosis is a gram-positive bacterium and is the etiologic agent of caseous lymphadenitis (CL) in small ruminants. This disease is characterized by the development of encapsulated granulomas in visceral and superficial lymph nodes, and its clinical treatment is refractory to antibiotic therapy. An important virulence factor of the Corynebacterium genus is the ability to produce biofilm; however, little is known about the characteristics of the biofilm produced by C. pseudotuberculosis and its resistance to antimicrobials. Silver nanoparticles (AgNPs) are considered as promising antimicrobial agents, and are known to have several advantages, such as a broad-spectrum activity, low resistance induction potential, and antibiofilm activity. Therefore, we evaluate herein the activity of AgNPs in C. pseudotuberculosis, through the determination of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), antibiofilm activity, and visualization of AgNP-treated and AgNP-untreated biofilm through scanning electron microscopy. The AgNPs were able to completely inhibit bacterial growth and inactivate C. pseudotuberculosis at concentrations ranging from 0.08 to 0.312 mg/mL. The AgNPs reduced the formation of biofilm in reference strains and clinical isolates of C. pseudotuberculosis, with interference values greater than 80% at a concentration of 4 mg/mL, controlling the change between the planktonic and biofilm-associated forms, and preventing fixation and colonization. Scanning electron microscopy images showed a significant disruptive activity of AgNP on the consolidated biofilms. The results of this study demonstrate the potential of AgNPs as an effective therapeutic agent against CL.

A280 DOES THE PLACEMENT OF A MANOMETRY PROBE WITH ENDOSCOPY AND CONSCIOUS SEDATION EFFECT MEASUREMENTS ON ENSUING HIGH RESOLUTION MANOMETRY? A RETROSPECTIVE COHORT STUDY IN PATIENTS POST-PERORAL ENDOSCOPIC MYOTOMY

Background

High resolution manometry (HRM) is the gold standard for diagnosis of esophageal motility disorders. This is traditionally conducted without sedation, using intranasal intubation with a manometry probe. Inserting the HRM probe immediately after endoscopic examination allows for endoscopic visualization and sedation for probe placement. This method is used commonly used for our patients who are post-peroral endoscopic myotomy (POEM). However, it is unclear whether short acting sedative drugs administered during endoscopy can affect contractility measurements during HRM.

Purpose

The purpose of this study was to determine if conscious sedation with short-acting anaesthetic agents (Midazolam and Fentanyl) influenced HRM readings in patients undergoing evaluation post-perioral endoscopic myotomy (POEM).

Method

We conducted a retrospective cohort study, comparing patients post-POEM who had endoscopy under conscious sedation with placement of the manometry probe versus those without preceeding endoscopy/sedation. Post-POEM patients who had undergone HRM over a 3-year period (2019-2022) were identified from motility lab records. Electronic charts were reviewed for data abstraction, and HRM parameters (resting lower esophageal pressure and integrated relaxation pressure) were determined for both groups and compared using t-tests, and error listed as standard error of the mean.

Result(s)

From 2019-2022, 15 patients underwent manometry using a non-endoscopic approach with no sedation and 25 underwent manometry following endoscopy with conscious sedation and placement of the probe during the procedure. In the latter group, HRM occurred within 2 hours of probe placement. The mean doses of fentanyl and midazolam were 115mcg (+/-29.7) and 3.3mg (+/-1.3) respectively. The mean end-expiratory lower esophageal sphincter pressure was 9.8 mmHg (+/- 2.9) in the non-endoscopic group and 26.24mmHg (+/- 5) in the endoscopy group (p <0.02). The median integrated relaxation pressure was 11.2 mmHg (+/-1.2) in the non-endoscopic group and 14.52mmHg (+/- 0.9) in those in the endoscopy group (p <0.04).

Conclusion(s)

In conclusion, this small, retrospective cohort study shows that manometry probe placement after endoscopy with conscious sedation may affect esophgeal HRM measurement parameters in the post-POEM patient population. Physicians should consider delaying HRM measurements for >4 hours to maximize clearance of the sedative medications.

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Disclosure of Interest

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Activity of Fusarium oxysporum-Based Silver Nanoparticles on Candida spp. Oral Isolates

Candida spp. resistant to commercially available antifungals are often isolated from patients with oral candidiasis, a situation that points to the need for the development of new therapies. Thus, we evaluated the activity of Fusarium oxysporum-based silver nanoparticles (AgNPs) on Candida spp. isolated from denture stomatitis lesions. Candida isolates were molecularly identified and submitted to susceptibility assays using AgNPs and commercial fungicides. The interference on biofilm formation and the mechanisms of action of AgNPs on Candida spp. were also investigated. Scanning electron microscopy was used to evaluate the morphology of AgNP-treated Candida. Candida albicans was the most frequent species isolated from denture stomatitis cases. All Candida spp. were susceptible to AgNPs at low concentrations, except Candida parapsilosis. AgNPs caused surface damage, cell disruption, and biofilm formation inhibition. The ergosterol supplementation protected C. albicans against the AgNP action. AgNPs are effective against Candida spp. and can be faced as a promising new therapeutic agent against oral candidiasis.

Activity of Ethanolic and Supercritical Propolis Extracts in Corynebacterium pseudotuberculosis and Its Associated Biofilm

Corynebacterium pseudotuberculosis is the etiological agent of caseous lymphadenitis in small ruminants, a chronic disease characterized by the development of granulomas in superficial and visceral lymph nodes as well as in several organs. An important characteristic of the infection with this bacterium is the formation of a biofilm and the absence of effective antibiotic therapy against the disease. From this scenario, the objective of this study was to evaluate the susceptibility of C. pseudotuberculosis to conventional antibiotics and to red, green, and brown propolis extracts obtained by the supercritical and ethanolic extraction methods as well as its activity in the bacterial biofilm. The results of the sensitivity test using antibiotics indicated a sensitivity of C. pseudotuberculosis strains to the antimicrobial agents. The ethanolic extract of green propolis and the supercritical red propolis extract showed the best antibacterial activities against planktonic C. pseudotuberculosis. A lower antimicrobial activity of the brown propolis extract was identified. Propolis extracts were effective in interfering with the formation of the C. pseudotuberculosis biofilm but had little activity on the consolidated biofilm. In conclusion, propolis extracts are more effective against C. pseudotuberculosis in the planktonic stage, being able to interfere with the formation of bacterial biofilm. However, the action of propolis extracts in a sessile and structured microbial biofilm is reduced.

Unlocking the potential of big data to support tactical performance analysis in professional soccer: A systematic review

In professional soccer, increasing amounts of data are collected that harness great potential when it comes to analysing tactical behaviour. Unlocking this potential is difficult as big data challenges the data management and analytics methods commonly employed in sports. By joining forces with computer science, solutions to these challenges could be achieved, helping sports science to find new insights, as is happening in other scientific domains. We aim to bring multiple domains together in the context of analysing tactical behaviour in soccer using position tracking data. A systematic literature search for studies employing position tracking data to study tactical behaviour in soccer was conducted in seven electronic databases, resulting in 2338 identified studies and finally the inclusion of 73 papers. Each domain clearly contributes to the analysis of tactical behaviour, albeit in - sometimes radically - different ways. Accordingly, we present a multidisciplinary framework where each domain's contributions to feature construction, modelling and interpretation can be situated. We discuss a set of key challenges concerning the data analytics process, specifically feature construction, spatial and temporal aggregation. Moreover, we discuss how these challenges could be resolved through multidisciplinary collaboration, which is pivotal in unlocking the potential of position tracking data in sports analytics.

Brazilian Green Propolis as a Therapeutic Agent for the Post-surgical Treatment of Caseous Lymphadenitis in Sheep

As antibiotics are ineffective when used to treat caseous lymphadenitis, the surgical excision of lesions is often required. Iodine solution (10%) is currently the choice for the post-surgical treatment; however, it may cause histotoxicity. Propolis are resinous substances composed by a mixture of different plants parts and molecules secreted by bees. As green propolis has already proven to possess anti-bacterial and wound healing properties, this study aimed to evaluate the use of a green propolis-based ointment as a therapeutic agent for the post-surgical treatment of caseous lymphadenitis. The caseous lesions of 28 sheep were surgically excised before dividing animals into two groups: (1) iodine-treated animals and (2) sheep treated with an ointment made with a previously characterized green propolis extract. Clinical data of animals, size of the scar area, the presence of moisture and secretion in the surgical wound, the humoral immune response against the bacterium and the susceptibility of C. pseudotuberculosis clinical isolates to the green propolis extract were analyzed. The green propolis-treated group presented complete healing of the surgical wound 1 week before the iodine-treated group. Additionally, animals treated with the green propolis ointment had fewer cases of wound secretion, but it was not statistically different from the iodine-treated group. No clinical signs indicating green propolis toxicity or other side effects were found, associated with a faster and more organized hair recovery by propolis use. The green propolis extract was able to inhibit the growth of 23 from the 27 C. pseudotuberculosis clinical isolates, with minimum inhibitory and minimum bactericide concentrations ranging from 01 to 08 mg/mL, and did not interfere with the humoral immune response against the bacterium. In addition, green propolis was able to inhibit biofilm formation by four of the C. pseudotuberculosis clinical isolates. We concluded that green propolis is a promising therapeutic agent to be used in the post-surgical treatment of caseous lymphadenitis in small ruminants due to its effects on surgical wound healing, hair recovery, inhibition of wound contamination and bacterial growth.

Alveolar ridge preservation using a non-resorbable membrane: randomized clinical trial with biomolecular analysis

The aim of this randomized clinical trial was to evaluate the newly formed tissues in post-extraction sockets and to compare ridge dimensional changes with and without the use of a dense polytetrafluoroethylene membrane (d-PTFE). Twenty human extraction sockets (lower molars and premolars) received either an intentionally exposed d-PTFE membrane (test group) or no biomaterial (control group). After 4 months, during preparation for implant placement, bone and gingival tissues were collected for histological and biomolecular analysis. Clinically, the test and control groups showed mean gains of keratinized gingiva of 4.30±1.20mm and 2.50±2.20mm, respectively. A reduction in ridge width was observed in the control (2.90±2.70mm) and test (3.30±2.00mm) groups. The bone height alteration ranged from a reduction of 0.12±1.60mm to a gain of 0.60±3.60mm on average for both groups. Analysis of gene expression (OPG/RANKL) in gingival fibroblasts and osteoblasts revealed no difference between the two groups. Ridge preservation using the d-PTFE membrane increased the formation of keratinized tissue. A reduction in width and mild reduction/gain in height of the alveolar ridge was observed in both groups. The membrane had no influence on the healing process.

Control of Salmonella Enteritidis in turkeys using organic acids and competitive exclusion product

AIM

To evaluate the use of organic acids (OAs) and competitive exclusion (CE) product administered continuously in the feed and transiently in drinking water on the control of Salmonella enterica subspecie enterica serotype Enteritidis (SE) prior to slaughter.

METHODS AND RESULTS

The influence of treatments were evaluated on pH, population of the lactic acid bacteria (LAB) and bacteria of the family Enterobacteriaceae, concentration of volatile fatty acids and SE colonization in the crop and caecum. The birds were challenged with SE 24 h before being slaughtered, and then, the caeca and crop were removed and subjected to SE counts. Continuous administration of OAs reduced the population of bacteria from the Enterobacteriaceae family in both crop and caecum, positively influenced the butyric acid concentration and reduced SE colonization in the caecum. The diet supplemented with CE product positively influenced the quantity of LAB in the crop and caecum, elevated the butyric acid concentration and reduced both Enterobacteriaceae quantity and SE colonization in the caecum. There was no effect from administering the treatments via drinking water on the variables measured.

CONCLUSIONS

Continuous supplementation in feed with OAs and CE product reduced SE colonization of the caeca.

SIGNIFICANCE AND IMPACT OF THE STUDY

Supplementation of OAs and CE product in diet to turkeys can reduce the SE load, potentially leading to a lower contamination risk of meat during slaughter.

Glial cell line-derived neurotrophic factor is a key neurotrophin in the postnatal enteric nervous system

BACKGROUND

The enteric nervous system (ENS) continues its structural and functional growth after birth, with formation of ganglia and the innervation of growing smooth muscle. However, little is known about factors in the postnatal intestine that influence these processes.

METHODS

We examined the presence and potential role of glial cell line-derived nerve growth factor (GDNF) in the rat postnatal ENS using neonatal tissue, primary co-cultures of the myenteric plexus, smooth muscle, and glial cells as well as cell lines of smooth muscle or glial cells.

KEY RESULTS

Western blot analysis showed that GDNF and its co-receptors rearranged during transfection (RET) and GDNF family receptor alpha-1 were expressed in the muscle layer of the neonatal and adult rat intestine. Immunohistochemistry localized the receptors for GDNF to myenteric neurons, while GDNF was localized to smooth muscle cells. In a co-culture model, GDNF but not nerve growth factor, brain derived neurotrophic factor or neurotrophin-3 significantly increased neuronal survival and more than doubled the numbers of neurites in vitro. RT-PCR, qPCR, Western blotting, ELISA, and immunocytochemistry as well as bioassays of neuronal survival and of RET phosphorylation all identified intestinal smooth muscle as the source of GDNF in vitro. GDNF also induced morphological changes in the structure and organization of neurons and axons, causing marked aggregation of neuronal cell bodies and collinear development of axons. As well, GDNF (50-150 ng mL(-1)) significantly increased [(3)H]-choline uptake and stimulated [(3)H]-acetylcholine release.

CONCLUSIONS & INFERENCES

We conclude that GDNF derived from intestinal smooth muscle cells is a key factor influencing the structural and functional development of postnatal myenteric neurons.

Wound infections in pediatric surgery: a study of 575 patients in a university hospital

Surgical wound infections (WI) remain a significant source of postoperative morbidity. This epidemiologic study was undertaken to determine retrospectively the incidence of postoperative WI in children in a university hospital and include critical comparisons of pediatric surgery WI rates between different international reports. As few data exist on postoperative WIs in pediatric patients, in contrast to numerous reports in adults, all infants and children undergoing operations in the pediatric surgical service in our institution during a 7-year period were reviewed for development of a WI, a total of 537 patients who underwent 575 operations. WIs occurred in 39 cases (6.7%). Clean wounds (56.8% of patients) had an infection rate of 2.7%, clean-contaminated (23.1%) 10.5%, contaminated (12.9%) 13.5%, and dirty/infected (7.2%) 14.6%. Increasing duration of operation ( P < 0.001), contamination at operation ( P < 0.001), and a new element in the operation - a resident or intern - ( P < 0.001) were all associated with a higher incidence of infection, despite efforts at infection-control practices including improved sterilization methods and barriers, surgical technique, and availability of antimicrobial prophylaxis. The total incidence of wound infection in this population was comparable to that in other reports. Comparing children who developed a wound infection with those who did not, there were no significant differences in age, sex, American Society of Anesthesiologists preoperative assessment score, length of preoperative hospitalization, location of operation (intensive care unit vs operating room), the presence of a coexisting disease or remote infection, or the use of perioperative antibiotics. These baseline data may aid in forming strategies to lower the risk of WI in children. Our results suggest that WIs in children are related more to factors at operation than to the patients overall physiologic status.

Functional significance of hypertrophy of the noninfarcted myocardium after myocardial infarction in humans

Hypertrophy of the noninfarcted left ventricle as a chronic response to myocardial infarction has been demonstrated in animals and at autopsy in humans. However, the functional significance of postmyocardial infarction hypertrophy is a subject of dispute. The purpose of this study was to determine the time course of development of postmyocardial infarction hypertrophy of the noninfarcted myocardium in humans and to assess its functional significance. Subcostal view, two-dimensional echocardiograms were recorded at rest and during peak exercise, 6 and 40 weeks postmyocardial infarction in 45 patients (16 anterior, 20 inferior, nine non-Q wave infarcts), for measurement of left ventricular mass and ejection fraction. The left ventricular mass index increased from 94 +/- 30 to 118 +/- 27 g/m2 (p less than 0.01) during the time of the two studies. There was a significant correlation between the change in left ventricular mass index and improved resting ejection fraction (r = 0.48, p less than 0.001) and exercise ejection fraction (r = 0.48, p less than 0.001) at the follow-up study. Of the 32 patients who increased their left ventricular mass index greater than 7%, 18 improved their rest ejection fraction greater than 0.05 units and 17 improved their exercise ejection fraction greater than 0.05 units. Conversely, of the 13 patients who failed to increase their left ventricular mass index, only three improved their rest ejection fraction and one improved the exercise ejection fraction (Fisher's exact test, p less than 0.05). We reached three conclusions. First, in humans, significant hypertrophy of the noninfarcted myocardium can be detected by two-dimensional echocardiography, 9 months postmyocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Teaching psychosomatic medicine

The authors want to present their experience over the last 20 years in teaching the psychosomatic approach to health professionals and students in their last years, i.e. medical doctors, psychologists, social workers, nurses and dentists. The teaching classes take up 2 years and their main function is to teach students psychosomatics as an approach, a proposal for an integral assistance in health care. They are aimed at emphasizing the human comprehension of pathology, trying to understand it within the scope of a historical and related process, without denying the organic reality of disease.