Comparative genetic characterization of CMY-2-type beta-lactamase producing pathogenic Escherichia coli isolated from humans and pigs suffering from diarrhea in Korea.

BACKGROUND: Pathogenic Escherichia coli are an important cause of bacterial infections in both humans and pigs and many of antimicrobials are used for the treatment of E. coli infection. The objective of this study was to investigate the characteristics and relationship between humans and pigs regarding third-generation cephalosporin resistance and CMY-2-producing E. coli in Korea. RESULTS: All 103 third-generation cephalosporin-resistant E. coli isolates showed multidrug resistance. Also, except for ß-lactam/ß-lactamase inhibitor combinations, all antimicrobials resistant rates were higher in pigs than in humans. A total of 36 isolates (humans: five isolates; pigs: 31 isolates) were positive for the CMY-2-encoding genes and thirty-two (88.9%) isolates detected class 1 integrons with 10 different gene cassette arrangements, and only 1 isolate detected a class 2 integron. The most common virulence genes in pigs were LT (71.0%), F18 (51.6%), and STb (51.6%), while stx2 (80.0%) was the most frequently detected gene in humans. Stx2 gene was also detected in pigs (6.5%). Interestingly, 36 CMY-2-producing E. coli isolates showed a high diversity of sequence types (ST), and ST88 was present in E. coli from both pigs (11 isolates) and humans (one isolate). CONCLUSION: Our findings suggest that a critical need for comprehensive surveillance of third-generation cephalosporin resistance is necessary to preserve the usefulness of third-generation cephalosporins in both humans and pigs.

TGF-ß secreted by human umbilical cord blood-derived mesenchymal stem cells ameliorates atopic dermatitis by inhibiting secretion of TNF-α and IgE.

Human mesenchymal stem cells (MSCs) are promising therapeutics for autoimmune diseases due to their immunomodulatory effects. In particular, human umbilical cord blood-derived MSCs (hUCB-MSCs) have a prominent therapeutic effect on atopic dermatitis (AD). However, the underlying mechanism is unclear. This study investigated the role of transforming growth factor-beta (TGF-ß) in the therapeutic effect of hUCB-MSCs on AD. Small interfering RNA (siRNA)-mediated depletion of TGF-ß disrupted the therapeutic effect of hUCB-MSCs in a mouse model of AD by attenuating the beneficial changes in histopathology, mast cell infiltration, tumor necrosis factor-alpha (TNF-α) expression, and the serum IgE level. To confirm that hUCB-MSCs regulate secretion of TNF-α, we investigated whether they inhibit TNF-α secretion by activated LAD2 cells. Coculture with hUCB-MSCs significantly inhibited secretion of TNF-α by LAD2 cells. However, this effect was abolished by siRNA-mediated depletion of TGF-ß in hUCB-MSCs. TNF-α expression in activated LAD2 cells was regulated by the extracellular signal-related kinase signaling pathway and was suppressed by TGF-ß secreted from hUCB-MSCs. In addition, TGF-ß secreted by hUCB-MSCs inhibited maturation of B cells. Taken together, our findings suggest that TGF-ß plays a key role in the therapeutic effect of hUCB-MSCs on AD by regulating TNF-α in mast cells and maturation of B cells.

Histiocytic pleural effusion: the strong clue to malignancy.

BACKGROUND: There have been many studies on the clinical characteristics of neutrophilic, lymphocytic, and/or eosinophilic pleural effusion. While caring for patients with pleural effusion, we found that histiocytic pleural effusion (HisPE) was not uncommon. However, few studies have explored HisPE. The purpose of the present study was to determine the clinical characteristics and etiologies of HisPE. METHODS: In this retrospective study, HisPE was defined as pleural fluid white blood cells comprised of ≥ 50% histiocytes. Using a clinical data warehouse, patients with HisPE among all patients aged >18 years who underwent thoracentesis and pleural fluid analysis between January 2010 and December 2019 at Ulsan University Hospital were enrolled. A total of 295 (9.0%) of 3279 patients who underwent thoracentesis were identified as HisPE patients. Among them, 201 with exudative HisPE were included. Clinical characteristics and etiologies were extracted from medical records and analyzed. RESULTS: Among the 201 patients with exudative HisPE, the major causes were malignant pleural effusion (n = 102 [50.7%]), parapneumonic effusion (n = 9 [4.5%]), and tuberculous pleurisy (n = 9 [4.5%]). In the 102 patients with malignant pleural effusion, the main types of cancer were lung (n = 42 [41.2%]), breast (n = 16 [15.7%]), and stomach cancer (n = 11 [10.8%]). Among lung cancers, adenocarcinoma (n = 34 [81.0%]) was the most common histology. CONCLUSIONS: The leading cause of exudative HisPE was malignancy, particularly lung cancer. Physicians should consider the possibility of malignant disease if histiocytes are predominantly present in pleural effusion.

Coronavirus Disease 19 (COVID-19) complicated with pneumonia in a patient with rheumatoid arthritis receiving conventional disease-modifying antirheumatic drugs.

In December 2019, numerous coronavirus disease 2019 (COVID-19) cases were reported in Wuhan, China, which has since spread throughout the world. However, its impact on rheumatoid arthritis (RA) patients is unknown. Herein, we report a case of COVID-19 pneumonia in a 61-year-old female RA patient who was receiving conventional disease-modifying antirheumatic drugs (cDMARDs). The patient presented with a 4-day history of myalgia and febrile sensation. COVID-19 was confirmed by real-time polymerase chain reaction (PCR). Chest X-ray showed increased opacity on the right lower lung area, and C-reactive protein level was slightly elevated. The patient was treated with antiviral agents (lopinavir/ritonavir), and treatment with cDMARDs was discontinued except hydroxychloroquine. Her symptoms and laboratory results gradually improved. Three weeks later, real-time PCR for COVID-19 showed negative conversion, and the patient was discharged without any complications.

Prevalence and characterization of Salmonella in two integrated broiler operations in Korea.

BACKGROUND: Vertical integration of the broiler industry allows producers to combine different biosecurity and sanitation practices, housing technologies, and feeding regimens to improve food safety. The purpose of this study was to investigate the prevalence and distribution of Salmonella, to determine the source of Salmonella contaminants, and to reveal the relationships between isolates at each step in the vertically integrated broiler production system in two representative integrated broiler companies in Korea. RESULTS: A total of 2148 samples were collected from 2 broiler breeder hatcheries, 14 broiler breeder farms, 3 broiler hatcheries, 16 broiler farms, 8 broiler transporting trucks and 6 slaughterhouses belonging to representative integrated broiler companies, and 205 (9.5%) of these samples were positive for Salmonella. The Salmonella prevalence in broiler hatcheries (34.0%) and broiler transporting trucks (62.5%) was higher (P < 0.05) whereas that in the broiler breeder hatchery (0.8%) was lower (P < 0.05), than the overall prevalence. Nine and 13 different Salmonella serotypes were isolated from integrated companies A and B, and the predominant serotypes were S. Virchow (39.7%) and S. Hadar (59.2%), respectively. Pulsed field gel electrophoresis patterns of isolates from the two operations showed significant genetic relatedness within a single system. CONCLUSIONS: In a comparison of the two operations that participated in this study, the prevalence of Salmonella differed significantly between the broiler breeder hatchery, and broiler hatcheries and broiler farms.

Exosomes derived from human umbilical cord blood mesenchymal stem cells stimulates rejuvenation of human skin.

Human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) play an important role in cutaneous wound healing, and recent studies suggested that MSC-derived exosomes activate several signaling pathways, which are conducive in wound healing and cell growth. In this study, we investigated the roles of exosomes that are derived from USC-CM (USC-CM Exos) in cutaneous collagen synthesis and permeation. We found that USC-CM has various growth factors associated with skin rejuvenation. Our in vitro results showed that USC-CM Exos integrate in Human Dermal Fibroblasts (HDFs) and consequently promote cell migration and collagen synthesis of HDFs. Moreover, we evaluated skin permeation of USC-CM Exos by using human skin tissues. Results showed that Exo-Green labeled USC-CM Exos approached the outermost layer of the epidermis after 3 h and gradually approached the epidermis after 18 h. Moreover, increased expressions of Collagen I and Elastin were found after 3 days of treatment on human skin. The results showed that USC-CM Exos is absorbed into human skin, it promotes Collagen I and Elastin synthesis in the skin, which are essential to skin rejuvenation and shows the potential of USC-CM integration with the cosmetics or therapeutics.

Human umbilical cord blood mesenchymal stem cell-derived PGE2 and TGF-ß1 alleviate atopic dermatitis by reducing mast cell degranulation.

Mesenchymal stem cell (MSC) is a promising tool for the therapy of immune disorders. However, their efficacy and mechanisms in treating allergic skin disorders are less verified. We sought to investigate the therapeutic efficacy of human umbilical cord blood-derived MSCs (hUCB-MSCs) against murine atopic dermatitis (AD) and to explore distinct mechanisms that regulate their efficacy. AD was induced in mice by the topical application of Dermatophagoides farinae. Naïve or activated-hUCB-MSCs were administered to mice, and clinical severity was determined. The subcutaneous administration of nucleotide-binding oligomerization domain 2 (NOD2)-activated hUCB-MSCs exhibited prominent protective effects against AD, and suppressed the infiltration and degranulation of mast cells (MCs). A ß-hexosaminidase assay was performed to evaluate the effect of hUCB-MSCs on MC degranulation. NOD2-activated MSCs reduced the MC degranulation via NOD2-cyclooxygenase-2 signaling. In contrast to bone marrow-derived MSCs, hUCB-MSCs exerted a cell-to-cell contact-independent suppressive effect on MC degranulation through the higher production of prostaglandin E2 (PGE2 ). Additionally, transforming growth factor (TGF)-ß1 production from hUCB-MSCs in response to interleukin-4 contributed to the attenuation of MC degranulation by downregulating FcεRI expression in MCs. In conclusion, the subcutaneous application of NOD2-activated hUCB-MSCs can efficiently ameliorate AD, and MSC-derived PGE2 and TGF-ß1 are required for the inhibition of MC degranulation.

Excessive microglial activation aggravates olfactory dysfunction by impeding the survival of newborn neurons in the olfactory bulb of Niemann-Pick disease type C1 mice.

Progressive olfactory impairment is one of the earliest markers of neurodegeneration. However, the underlying mechanism for this dysfunction remains unclear. The present study investigated the possible role of microgliosis in olfactory deficits using a mouse model of Niemann-Pick disease type C1 (NPC1), which is an incurable neurodegenerative disorder with disrupted lipid trafficking. At 7weeks of age, NPC1 mutants showed a distinct olfactory impairment in an olfactory test compared with age-matched wild-type controls (WT). The marked loss of olfactory sensory neurons within the NPC1 affected olfactory bulb (NPC1-OB) suggests that NPC1 dysfunction impairs olfactory structure. Furthermore, the pool of neuroblasts in the OB was diminished in NPC1 mice despite the intact proliferative capacity of neural stem/progenitor cells in the subventricular zone. Instead, pro-inflammatory proliferating microglia accumulated extensively in the NPC1-OB as the disease progressed. To evaluate the impact of abnormal microglial activation on olfaction in NPC1 mice, a microglial inhibition study was performed using the anti-inflammatory agent Cyclosporin A (CsA). Importantly, long-term CsA treatment in NPC1 mice reduced reactive microgliosis, restored the survival of newly generated neurons in the OB and improved overall performance on the olfactory test. Therefore, our study highlights the possible role of microglia in the regulation of neuronal turnover in the OB and provides insight into the possible therapeutic applications of microglial inhibition in the attenuation or reversal of olfactory impairment.

Human umbilical cord blood mesenchymal stem cells reduce colitis in mice by activating NOD2 signaling to COX2.

BACKGROUND & AIMS: Decreased levels or function of nucleotide-binding oligomerization domain 2 (NOD2) are associated with Crohn's disease. NOD2 regulates intestinal inflammation, and also is expressed by human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs), to regulate their differentiation. We investigated whether NOD2 is required for the anti-inflammatory activities of MSCs in mice with colitis. METHODS: Colitis was induced in mice by administration of dextran sulfate sodium or trinitrobenzene sulfonic acid. Mice then were given intraperitoneal injections of NOD2-activated hUCB-MSCs; colon tissues and mesenteric lymph nodes were collected for histologic analyses. A bromodeoxyuridine assay was used to determine the ability of hUCB-MSCs to inhibit proliferation of human mononuclear cells in culture. RESULTS: Administration of hUCB-MSCs reduced the severity of colitis in mice. The anti-inflammatory effects of hUCB-MSCs were greatly increased by activation of NOD2 by its ligand, muramyl dipeptide (MDP). Administration of NOD2-activated hUCB-MSCs increased anti-inflammatory responses in colons of mice, such as production of interleukin (IL)-10 and infiltration by T regulatory cells, and reduced production of inflammatory cytokines. Proliferation of mononuclear cells was inhibited significantly by co-culture with hUCB-MSCs that had been stimulated with MDP. MDP induced prolonged production of prostaglandin (PG)E2 in hUCB-MSCs via the NOD2-RIP2 pathway, which suppressed proliferation of mononuclear cells derived from hUCB. PGE2 produced by hUCB-MSCs in response to MDP increased production of IL-10 and T regulatory cells. In mice, production of PGE2 by MSCs and subsequent production of IL-10 were required to reduce the severity of colitis. CONCLUSIONS: Activation of NOD2 is required for the ability of hUCB-MSCs to reduce the severity of colitis in mice. NOD2 signaling increases the ability of these cells to suppress mononuclear cell proliferation by inducing production of PGE2.

Persistently retained interferon-gamma responsiveness in individuals with a history of pulmonary tuberculosis.

The interferon gamma (IFN-γ) release assays (IGRAs) are the best method of detecting Mycobacterium tuberculosis infection. However, reports on IGRAs results obtained during and right after the treatment of tuberculosis (TB) have presented differing results. Some studies have shown declining responses, whereas other reports described persistent, fluctuating, or increasing responses. We postulated that the IGRA-positivity will decrease or revert long time after treatment of TB, and thus, evaluated the response of IGRA in subjects with a history of pulmonary TB. Seventy subjects (M:F = 51:19; age = 53.2 ± 11.8 years) underwent tuberculin skin tests (TSTs) and IGRA. The interval of time elapsed after the completion of anti-TB treatment was < 10 years for 16 subjects, 10-20 years for 13 subjects, 20-30 years for 16 subjects, and ≥ 30 years for 25 subjects. The TST was positive in 49 subjects (74%) and negative in 17 subjects (26%). The IGRA was positive in 52 subjects (74%) and negative in 18 subjects (26%). The IFN-γ level and the size of induration showed good correlation (r = 0.525, P < 0.001). However, the correlation between time elapsed after the completion of anti-TB treatment and the size of induration or that between time and the IFN-γ level was not significant. The TST and IGRA were positive in 72.7% and 68.0% of subjects ≥ 30 years after the treatment of pulmonary TB. In conclusion, majority of subjects with a history of pulmonary TB are IGRA-positive, even a few decades after the completion of anti-TB treatment.

Histopathological and Immunohistochemical Characterization of Sebaceous Adenoma and Epithelioma in Dogs.

Sebaceous gland tumors are neoplasms originating from the sebaceous gland and are the third most common type of skin tumor, accounting for 21-35% of all cutaneous neoplasms in dogs. According to their histopathological characteristics, sebaceous gland tumors can be classified into adenoma as a benign tumor and epithelioma as a malignant tumor. Sebaceous epithelioma is distinguished from sebaceous adenoma by containing 90% or more reserve cells. However, this simple numerical criterion is insufficient to histologically distinguish between epitheliomas and adenomas. In addition, sebaceoma in humans, a similar tumor to sebaceous epithelioma, is a term used for tumors with more than 50% of reserve cells, unlike epithelioma. Therefore, we aimed to compare and characterize the histological and immunohistochemical profiles of comprehensive sebaceous adenoma, epithelioma, and borderline tumors that have more than 50% but less than 90% of reserve cells. A total of 14 canine sebaceous tumors were diagnosed as seven adenomas, four borderline tumors, and three epitheliomas. Histologically, the sebaceous adenomas showed nodules consisting of mature sebocytes surrounded by monolayer basaloid cells. In contrast, the portion of the reserve cells was increased, the portion of lipidized cells was decreased, and the majority of lipidized cells were found to be immature in sebaceous epithelioma. In the sebaceous adenomas, necrosis was not observed and mitotic figures were rarely seen. However, necrosis and mitotic figures were highly frequent in both borderline tumor and sebaceous epithelioma. Immunohistochemistry revealed that borderline tumor and sebaceous epithelioma showed significantly higher expression against Ki-67 than sebaceous adenoma. We conclude that it is more accurate to employ the cut-off value of 50% reserve cells in humans rather than the current 90% reserve cells for classifying sebaceous gland tumors in dogs, thereby providing new insight into the characterization of the sebaceous gland tumors.

A case of alveolar soft part sarcoma of the pleura.

Alveolar soft part sarcoma (ASPS) is a rare malignant soft-tissue neoplasm of unknown histogenesis. The two main sites of occurrence are the lower extremities in adults and the head and neck in children. We report the first case of pleural ASPS occurring in a 58-yr-old man who presented with progressive dyspnea. A computed tomographic scan of the thorax revealed a large enhancing pleural mass with pleural effusion in the left hemithorax. Wide excision of the pleural mass was performed. Histologically, the tumor consisted of organoid nests of large polygonal cells, the cytoplasm of which had eosinophilic and D-PAS positive granules. Immunohistochemical staining showed that the tumor cell nuclei were positive for transcription factor 3 (TFE3). The pleural ASPS with multiple bone metastases recurred 1 yr after surgery and the patient died of acute pulmonary embolism 1.5 yr after diagnosis.

Development of a Method for the Fast Detection of Extended-Spectrum ß-Lactamase- and Plasmid-Mediated AmpC ß-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae from Dogs and Cats in the USA.

Antibiotic resistance, such as resistance to beta-lactams and the development of resistance mechanisms, is associated with multifactorial phenomena and not only with the use of third-generation cephalosporins. Many methods have been recommended for the detection of ESBL and pAmpC ß-lactamase production but they are very subjective and the appropriate facilities are not available in most laboratories, especially not in clinics. Therefore, for fast clinical antimicrobial selection, we need to rapidly detect ESBL- and pAmpC ß-lactamase-producing bacteria using a simple method with samples containing large amounts of bacteria. For the detection of ESBL- and pAmpC phenotypes and genes, the disk diffusion test, DDST and multiplex PCR were conducted. Of the 109 samples, 99 (90.8%) samples were grown in MacConkey broth containing cephalothin, and 71 samples were grown on MacConkey agar containing ceftiofur. Of the 71 samples grown on MacConkey agar containing ceftiofur, 58 Escherichia coli and 19 Klebsiella pneumoniae isolates, in particular, harbored ß-lactamase genes. Of the 38 samples that did not grow in MacConkey broth containing cephalothin or on MacConkey agar containing ceftiofur, 32 isolates were identified as E. coli, and 10 isolates were identified as K. pneumoniae; ß-lactamase genes were not detected in these E. coli and K. pneumoniae isolates. Of the 78 ESBL- and pAmpC ß-lactamase-producing E. coli and K. pneumoniae, 55 (70.5%) isolates carried one or more ESBL genes and 56 (71.8%) isolates carried one or more pAmpC ß-lactamase genes. Our method is a fast, and low-cost tool for the screening of frequently encountered ESBL- and pAmpC ß-lactamase-producing bacteria and it would assist in diagnosis and improve therapeutic treatment in animal hospitals.

Comparative Genetic Characterization of CTX-M-Producing Escherichia coli Isolated from Humans and Pigs with Diarrhea in Korea Using Next-Generation Sequencing.

Pathogenic E. coli causes intra- and extraintestinal diseases in humans and pigs and third-generation cephalosporins are the primary option for the treatment of these diseases. The objective of this study was to investigate the characteristics and correlation between CTX-M-producing E. coli from humans and pigs regarding CTX-M-producing E. coli using next-generation sequencing and bioinformatic tools. Among the 24 CTX-M-producing E. coli, three types of CTX-M genes (CTX-M-12, CTX-M-14, and CTX-M-15) were detected in humans and four types of CTX-M genes (CTX-M-14, CTX-M-15, CTX-M-55, and CTX-M-101) were detected in pigs. A total of 24 CTX-M-producing E. coli isolates also showed the following antimicrobial resistance genes: other B-Lactam resistance gene (75.0%); aminoglycoside resistance genes (75.0%); phenicol resistance genes (70.8%); tetracycline resistance genes (70.8%); sulfonamide resistance genes (66.7%); quinolone resistance genes (62.5%); trimethoprim resistance genes (54.2%); and fosfomycin resistance genes (8.3%). FII (92.3%) and FIB (90.9%) were the most common plasmid replicon in humans and pigs, respectively. A total of thirty-eight different genes associated with virulence 24 CTX-M-producing E. coli and all isolates contained at least more than one virulence gene. A total of 24 CTX-M-producing E. coli isolates showed 15 diverse sequence types (STs): thirteen isolates from human belonged to 6 different STs, and 11 isolates from pig belonged to 9 different STs. The presence of virulence genes in E. coli together with antimicrobial resistance genes (including CTX-M genes) emphasizes the necessity of comprehensive surveillance and persistent monitoring of the food chain to avoid all types of bacterial contamination, regardless of human or pig origin.

Effects of Antimicrobial Administration Route on Growth and Antimicrobial Resistance in Weaned Piglets.

This study aimed to determine how the route of antimicrobial administration affected the growth performance of weaned piglets. Additionally, we aimed to investigate potential differences between antimicrobial resistance developed by antimicrobials administered orally through drinking water, and those administered through feed, in weaned piglets. The research was undertaken on a farm housing 500 sows and involved 150 weaned piglets at 21 days of age. These piglets were evenly distributed into three groups of equal size: water, feed, and control. Antimicrobials were administered through drinking water and feed in the water and feed groups, respectively, while the control group received no antimicrobial treatment. The observation of piglets continued until they reached 70 days of age. The feed conversion ratio in the water group (1.7 ± 0.78) was significantly higher than in the control (2.4 ± 1.77) and feed (2.7 ± 1.68) groups. Additionally, the route of administration did not affect antimicrobial resistance rates. Based on these results, it can be inferred that administering antimicrobials through drinking water is advantageous for pig farming.

Comparative genetic characterisation of third-generation cephalosporin-resistant Escherichia coli isolated from integrated and conventional pig farm in Korea.

OBJECTIVES: Pig-farming systems consist of integrated or conventional farms, and many antimicrobials are used to treat bacterial infections. The objective of this study was to compare characteristics of third-generation cephalosporin resistance and extended-spectrum ß-lactamase (ESBL)/pAmpC ß-lactamase-producing Escherichia coli between integrated and conventional farms. METHODS: Third-generation cephalosporin-resistant E. coli was collected from integrated and conventional pig farms from 2021 to 2022. Polymerase chain reaction and DNA sequencing were performed for the detection of ß-lactamase-encoding genes, molecular analysis, and identification of genetic relationships. To determine the transferability of ß-lactamase genes, conjugation assays were conducted. RESULTS: Antimicrobial resistance rates were higher in conventional farms than in integrated farms; ESBL- and pAmpC-lactamase-producing E. coli rates were higher in conventional farms (9.8%) than in integrated farms (3.4%). Fifty-two (6.5%) isolates produced ESBL/pAmpC ß-lactamase genes. Isolates from integrated farms harboured CTX-15 (3 isolates), CTX-55 (9 isolates), CTX-229 (1 isolate), or CMY-2 (1 isolate) genes; isolates from conventional farms harboured CTX-1 (1 isolate), CTX-14 (6 isolates), CTX-15 (2 isolates), CTX-27 (3 isolates), CTX-55 (14 isolates), CTX-229 (1 isolate), and CMY-2 (11 isolates) genes. Of the 52 ESBL/pAmpC ß-lactamase-producing E. coli isolates, class 1 integrons with 11 different gene cassette arrangements were detected in 39 (75.0%) isolates, and class 2 integrons were detected in 3 isolates. The most common sequence type in both integrated and conventional farms was ST5229, followed by ST101, and then ST10. CONCLUSION: Third-generation cephalosporin-resistant patterns and molecular characteristics differed between integrated and conventional farms. Our findings suggest that continuous monitoring of third-generation cephalosporin resistance on pig farms is necessary to prevent the dissemination of resistant isolates.

Safety and Effectiveness of Regdanvimab for COVID-19 Treatment: A Phase 4 Post-marketing Surveillance Study Conducted in South Korea.

INTRODUCTION: Regdanvimab, a neutralising monoclonal antibody (mAb) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), received approval for the treatment of coronavirus disease 2019 (COVID-19) in South Korea in 2021. The Ministry of Food and Drug Safety in South Korea mandate that new medications be re-examined for safety and effectiveness post-approval in at least 3000 individuals. This post-marketing surveillance (PMS) study was used to evaluate the safety and effectiveness of regdanvimab in real-world clinical care. METHODS: This prospective, multicentre, phase 4 PMS study was conducted between February 2021 and March 2022 in South Korea. Eligible patients were aged ≥ 18 years with confirmed mild COVID-19 at high risk of disease progression or moderate COVID-19. Patients were hospitalised and treated with regdanvimab (40 mg/kg, day 1) and then monitored until discharge, with a follow-up call on day 28. Adverse events (AEs) were documented, and the COVID-19 disease progression rate was used to measure effectiveness. RESULTS: Of the 3123 patients with COVID-19 infection identified, 3036 were eligible for inclusion. Approximately 80% and 5% of the eligible patients were diagnosed with COVID-19 during the delta- and omicron-dominant periods, respectively. Median (range) age was 57 (18-95) years, and 50.6% of patients were male. COVID-19 severity was assessed before treatment, and high-risk mild and moderate COVID-19 was diagnosed in 1030 (33.9%) and 2006 (66.1%) patients, respectively. AEs and adverse drug reactions (ADRs) were experienced by 684 (22.5%) and 363 (12.0%) patients, respectively. The most common ADR was increased liver function test (n = 62, 2.0%). Nine (0.3%) patients discontinued regdanvimab due to ADRs. Overall, 378 (12.5%) patients experienced disease progression after regdanvimab infusion, with extended hospitalisation/re-admission (n = 300, 9.9%) as the most common reason. Supplemental oxygen was required by 282 (9.3%) patients. Ten (0.3%) patients required intensive care monitoring and 3 (0.1%) died due to COVID-19. CONCLUSION: This large-scale PMS study demonstrated that regdanvimab was effective against COVID-19 progression and had an acceptable safety profile when used in real-world clinical practice.

The simplest method for in vitro ß-cell production from human adult stem cells.

Diabetes mellitus is a challenging autoimmune disease. Biomedical researchers are currently exploring efficient and effective ways to solve this challenge. The potential of stem cell therapies for treating diabetes represents one of the major focuses of current research on diabetes treatment. Here, we have attempted to differentiate adult stem cells from umbilical cord blood-derived mesenchymal cells (UCB-MSC), Wharton's jelly-derived mesenchymal stem cells (WJ-MSC) and amniotic epithelial stem cells (AE-SC) into insulin-producing cells. The serum-free protocol developed in this study resulted in the differentiation of cells into definitive endoderm, pancreatic foregut, pancreatic endoderm and, finally, pancreatic endocrine cells, which expressed the marker genes SOX17, PDX1, NGN3, NKX6.1, INS, GCG, and PPY, respectively. Detection of the expression of the gap junction-related gene connexin-36 (CX36) using RT-PCR provided conclusive evidence for insulin-producing cell differentiation. In addition to this RT-PCR result, insulin and C-peptide protein were detected by immunohistochemistry and ELISA. Glucose stimulation test results showed that significantly greater amounts of C-peptide and insulin were released from differentiated cells than from undifferentiated cells. In conclusion, the methods investigated in this study can be considered an effective and efficient means of obtaining insulin-producing cells from adult stem cells within a week.

Relationship between virulence factors and antimicrobial resistance genes of pathogenic Escherichia coli from diarrheic weaned piglets.

A total of 690 pathogenic Escherichia (E.) coli isolates from weaned piglets were examined for antimicrobial resistance phenotypes, resistance genes, and virulence gene profiles. Also, 29 enterotoxigenic E. coli (ETEC) and 35 Shiga-toxin producing E. coli (STEC) isolates were analyzed using multi-locus sequence typing (MLST). Comparisons of the associations between antimicrobial resistance phenotypes, resistance genes, and virulence genes were performed separately by assessing odds ratio (OR). Although majorities of associations were not confirmed however, we found that associations between specific virulence factors-antimicrobial resistance. F18 encoding isolates showed association with resistance to cefazolin (OR = 3.08) and cefoxitin (OR = 3.65), and also with antimicrobial resistance gene mcr-3 (OR = 4.58). There was a high correlation between F4-STb (OR = 13.56), F4-LT (OR = 8.77), F4-EAST-I (OR = 4.97), and F18-Stx2e (OR = 3.83). Most of ETEC (21 of 29, 72.4%) isolates were assigned to ST100, and 20 of 35 STEC isolates (57.1%) were ST1. There were 5 clusters, and each cluster showed specific antimicrobial resistance patterns. Cluster I showed resistance to gentamicin, streptomycin, neomycin, nalidixic acid, ciprofloxacin, norfloxacin, trimethoprim / sulfamethoxazole, and tetracyclines whereas, cluster V showed resistance to ampicillin, amoxicillin / clavulanic acid, cephalothin, cefoxitin, cefazolin, norfloxacin, and colistin. Although there is need to do more experiments to clarify why certain virulence factors showed relationship with antimicrobial resistance, it is clear that there is a significant association between specific virulence genes and antimicrobial resistance in E. coli from weaned piglets with enteric colibacillosis in Korea.

Comparison of antimicrobial resistance and molecular characterization of Escherichia coli isolates from layer breeder farms in Korea.

In Korea, 4 big layer companies that possess one grandparent and 3 parent stocks are in charge of 100% of the layer chicken industry. In this study, we investigated the antimicrobial resistance of commensal 578 E. coli isolated from 20 flocks of 4-layer breeder farms (A, B, C, and D), moreover, compared the characteristics of their resistance and virulence genes. Isolates from farms B and D showed significantly higher resistance to the ß-lactam antimicrobials (amoxicillin, ampicillin, and 1st-, 2nd-, and 3rd-generation cephalosporins). However, resistance to ciprofloxacin, nalidixic acid, and tetracycline was significantly higher in the isolates from farm A (P < 0.05). Interestingly, the isolates from farm C showed significantly lower resistance to most antimicrobials tested in this study. The isolates from farms B, C, and D showed the high multiple resistance to the 3 antimicrobial classes. Furthermore, the isolates from farm A showed the highest multiple resistance against the 5 classes. Among the 412 ß-lactam-resistant isolates, 123 (29.9%) carried blaTEM-1, but the distribution was significantly different among the farms from 17.5% to 51.4% (P < 0.05). Similarly, the most prevalent tetracycline resistance gene in the isolates from farms B, C, and D was tetA (50.0-77.0%); however, the isolates from farm A showed the highest prevalence in tetB (70.6%). The distribution of quinolone (qnrB, qnrD, and qnrS) and sulfonamide (su12)-resistant genes were also significantly different among the farms but that of chloramphenicol (catA1)- and aminoglycoside (aac [3]-II, and aac [6']-Ib)-resistant genes possessed no significant difference among the farms. Moreover, the isolates from farm C showed significantly higher prevalence in virulence genes (iroN, ompT, hlyF, and iss) than the other 3 farms (P < 0.05). Furthermore, the phenotypic and genotypic characteristics of E. coli isolates were significantly different among the farms, and improved management protocols are required to control of horizontal and vertical transmission of avian disease, including the dissemination of resistant bacteria in breeder flocks.