Clinicopathological findings in patients with COVID-19-associated ischaemic enterocolitis.

AIMS: Coronavirus disease 2019 (COVID-19) has been recognised as a predominantly respiratory tract infection, but some patients manifest severe systemic symptoms/coagulation abnormalities. The aim of this study was to evaluate the impact of severe COVID-19 infection on the gastrointestinal tract. METHODS AND RESULTS: We examined clinicopathological findings in 28 resected ischaemic bowels from 22 patients with severe COVID-19. Most patients required intubation preoperatively and presented with acute decompensation shortly before surgery. D-dimer levels were markedly elevated in all measured cases (mean, 5394 ng/ml). Histologically, 25 cases (19 patients) showed evidence of acute ischaemia with necrosis. In this group, the most characteristic finding was the presence of small vessel fibrin thrombi (24 of 25 cases, 96%), which were numerous in 64% of cases. Patients with COVID-19 were significantly more likely than a control cohort of 35 non-COVID-19-associated acute ischaemic bowels to show isolated small intestine involvement (32% versus 6%, P < 0.001), small vessel fibrin thrombi (100% versus 43%, P < 0.001), submucosal vessels with fibrinous degeneration and perivascular neutrophils (90% versus 54%, P < 0.001), fibrin strands within submucosal vessels (58% versus 20%, P = 0.007), and histological evidence of pneumatosis (74% versus 34%, P = 0.010). Three cases in this cohort had histopathological findings normally seen in the setting of chronic ischaemia, notably prominent fibroblastic proliferation affecting the outer layer of the muscularis propria. CONCLUSIONS: Herein, we describe the histopathological findings in COVID-19-associated ischaemic bowels and postulate a relationship with the hypercoagulable state seen in patients with severe COVID-19 infection. Additional experience with these cases may further elucidate specific features or mechanisms of COVID-19-associated ischaemic enterocolitis.

Multiple thrombosis associated with Cytomegalovirus enterocolitis in an immunocompetent patient: a case report.

BACKGROUND: Cytomegalovirus (CMV) is reported to have thrombogenic characteristics that activate factor X in vitro and stimulate the production of factor VIII and von Willebrand factor (vWF). Thrombosis associated with CMV infection is prevalent among immunocompromised patients and predominantly presents as a solitary large thrombus in the deep vein, pulmonary artery, splanchnic arteriovenous ducts, or other similar sites. Multiple thrombi, however, are rarely observed in such cases. Here, we report about an immunocompetent man with multiple microthrombi associated with CMV infection. CASE PRESENTATION: A 72-year-old Japanese man who complained of abdominal pain was hospitalized with multiple colonic stenosis. He was later diagnosed with CMV enterocolitis and treated with ganciclover from Day 27 post-admission. During hospitalization, the patient developed thrombi in his fingers. He was initially treated with anticoagulant therapy (rivaroxaban); however, the therapy was discontinued owing to a prolonged activated thromboplastin time and an elevated international normalized ratio of prothrombin time. Instead, vitamin K and fresh-frozen plasma were administered. Nevertheless, his coagulation profile remained abnormal. Eventually, he developed colonic perforation and had to undergo emergency surgery. An intraoperative specimen showed several microthrombi in the middle and small arteriovenous ducts of his small and large intestines. The patient's coagulopathy improved preoperatively, and his overall condition improved postoperatively. Since the activation of ADAMTS13 was reduced remarkably, the thrombotic tendency was determined to be a thrombotic microangiopathy-like condition owing to increased vWF. We could not attribute the coagulopathy to any other cause except CMV infection; therefore, we concluded that this was a case of multiple thrombosis associated with CMV. CONCLUSIONS: We present an extremely rare case of a patient with multiple thrombotic microangiopathy-like microthrombosis caused by CMV infection. Our findings suggest that CMV infection may be considered as a differential diagnosis for immunocompetent individuals who present with thrombosis of unspecified cause.

Cytomegalovirus haemorrhagic enterocolitis associated with severe infection with COVID-19.

We present a case of haemorrhagic enterocolitis in a patient with SARS-CoV-2 who recovered from respiratory failure after support with venovenous extracorporeal membrane oxygenation. We describe clinicopathological features consistent with the systemic coinfection/reactivation of cytomegalovirus (CMV) concurrent with COVID-19 infection and the protracted clinical course of resolution of gastrointestinal inflammation after the treatment of CMV infection. Stool PCR, abdominal CT perfusion scan and histological examination of ileal and colonic tissues excluded enterocolitis secondary to other causes of infection (common viral, bacterial and protozoal gastrointestinal pathogens), macrovascularand microvascular ischaemia and classic inflammatory bowel disease, respectively. We propose possible synergistic pathophysiologic mechanisms for enterocolitis complicating severe COVID-19 infection: (1) T lymphocyte depletion and immune response dysregulation, (2) use of immunomodulators in the management of severe COVID-19 infection and (3) high concentration of ACE-2 receptors for COVID-19 virus in the gastrointestinal tract.

Exosome-mediated human norovirus infection.

Human norovirus (HuNoV) is a leading cause of acute gastroenteritis. Outbreaks normally occur via the fecal-oral route. HuNoV infection is thought to occur by viral particle transmission, but increasing evidence suggests a function for exosomes in HuNoV infection. HuNoV is contained within stool-derived exosomes, and exosome-associated HuNoV has been shown to replicate in human intestinal enteroids. In this study, we examine exosome-associated HuNoV infection of Vero cells and show that exosomes containing HuNoV may attach, infect, and be passaged in Vero cells. These findings support earlier findings and have implications for developing HuNoV disease intervention strategies.

Aminopeptidase N Expression, Not Interferon Responses, Determines the Intestinal Segmental Tropism of Porcine Deltacoronavirus.

Porcine deltacoronavirus (PDCoV) is an economically important enteropathogen of swine with worldwide distribution. PDCoV primarily infects the small intestine instead of the large intestine in vivo However, the underlying mechanism of PDCoV tropism to different intestinal segments remains poorly understood as a result of the lack of a suitable in vitro intestinal model that recapitulates the cellular diversity and complex functions of the gastrointestinal tract. Here, we established the PDCoV infection model of crypt-derived enteroids from different intestinal segments. Enteroids were susceptible to PDCoV, and multiple types of different functional intestinal epithelia were infected by PDCoV in vitro and in vivo We further found that PDCoV favorably infected the jejunum and ileum and restrictedly replicated in the duodenum and colon. Mechanistically, enteroids from different intestinal regions displayed a distinct gene expression profile, and the differential expression of primary viral receptor host aminopeptidase N (APN) instead of the interferon (IFN) responses determined the susceptibility of different intestinal segments to PDCoV, although PDCoV substantially elicited antiviral genes production in enteroids after infection. Additional studies showed that PDCoV infection significantly induced the expression of type I and III IFNs at the late stage of infection, and exogenous IFN inhibited PDCoV replication in enteroids. Hence, our results provide critical inputs to further dissect the molecular mechanisms of PDCoV-host interactions and pathogenesis.IMPORTANCE The zoonotic potential of the PDCoV, a coronavirus efficiently infecting cells from a broad range species, including porcine, chicken, and human, emphasizes the urgent need to further study the cell and tissue tropism of PDCoV in its natural host. Herein, we generated crypt stem cell-derived enteroids from porcine different intestinal regions, which well recapitulated the events in vivo of PDCoV infection that PDCoV targeted multiple types of intestinal epithelia and preferably infected the jejunum and ileum over the duodenum and colon. Mechanistically, we demonstrated that the expression of APN receptor rather than the IFN responses determined the susceptibility of different regions of the intestines to PDCoV infection, though PDCoV infection markedly elicited the IFN responses. Our findings provide important insights into how the distinct gene expression profiles of the intestinal segments determine the cell and tissue tropism of PDCoV.

Cytomegalovirus Colitis Followed by Colonic Pseudolipomatosis and Gastric Emphysema in a Post-resuscitation Patient.

A 64-year-old Japanese man suffered cardiopulmonary arrest, which may have resulted from sepsis and/or hyperosmolar hyperglycemic non-ketonic coma, and was admitted after successful resuscitation. He had watery diarrhea on day 18 and was diagnosed with cytomegalovirus enterocolitis. In addition, computed tomography performed on day 27 and colonoscopy revealed gastric emphysema and intestinal pseudolipomatosis, respectively. This report is the first to describe a patient with cytomegalovirus enterocolitis and subsequent gastric emphysema and pseudolipomatosis. Gastrointestinal cytomegalovirus infection may underlie gastric emphysema and intestinal pseudolipomatosis, particularly in patients with relative or obvious immune dysfunction.

MODERN ETIOLOGICAL STRUCTURE OF ACUTE GASTROENTEROCOLITIS IN THE SOUTHERN UKRAINE.

The etiological structure of the acute diarrhoeal infections among the population of the Odessa region during 2015-2017 was analyzed. Based on the registered cases, an assessment of the frequency of hospitalization of sick persons from different age groups was undertaken. The most frequent pathogens from 18 detected bacterial causative agents were St. aureus, Kl. pneumoniae, Ps. aeruginosa, E. coli, Pr. vulgaris, Ent.cloacae. During 2016-2017 the mixed infection was detected in 54 fecal samples. Bacterial-virus associations were detected in 20 samples and were presented in St. aureus, Kl. pneumoniae, Ps. Aeruginosa and Rotavirus. During the summer period of 2016, the detection rate of rota-, noro-, adenovirus antigens in the examined fecal samples of adult patients was 13.60%. According to the results of genotyping of the circulating rotaviruses strains in 2016, strains G1P[8] (46.70%) and G3P[8] (26.70%) are most commonly detected.

Detection of cytomegalovirus DNA in fecal samples in the diagnosis of enterocolitis after allogeneic stem cell transplantation.

BACKGROUND: Cytomegalovirus enterocolitis is a rare but potentially life threatening complication after allogeneic stem cell transplantation. Its early diagnosis and treatment are essential for a successful outcome. OBJECTIVE: To determine the potential benefit of fecal CMV DNA detection in the diagnosis of CMV colitis among stem cell transplant recipients. STUDY DESIGN: Biopsies from the lower gastrointestinal tract, taken during 69 episodes of diarrhea, were compared with fecal samples previously examined for CMV DNA in 45 patients after allogeneic stem cell transplantation. RESULTS: Six confirmed cases of CMV colitis were observed, with 16 out of 69 (23%) fecal samples proving positive for CMV DNA. Only one positive sample correlated with histologically confirmed CMV colitis, and 15 samples were evaluated as false positive. These results provide a 16.7% sensitivity and 76.2% specificity in the diagnosis of CMV enterocolitis. CONCLUSION: The examination of fecal samples for the presence of CMV DNA has very low potential in the diagnosis of CMV enterocolitis after allogeneic stem cell transplantation; therefore, a biopsy of the gastrointestinal mucosa is still warranted for correct diagnosis.

Characteristics of cytomegalovirus enterocolitis in patients with or without inflammatory bowel diseases.

OBJECTIVES: Cytomegalovirus (CMV) disease is more common in immunocompromised patients but may occur in people with normal immune function. In addition, CMV enterocolitis can aggravate inflammatory bowel diseases (IBD), but there was little knowledge of differences in clinical and endoscopic features of CMV enterocolitis between patients with IBD and without IBD. The aim of this study was to determine the difference in clinical implication in CMV enterocolitis between the IBD patients and non-IBD patients. METHODS: This was a retrospective study of 82 patients with CMV enterocolitis based on the pathologic findings at two tertiary referral hospitals from 2003 to 2013. Clinical and endoscopic characteristics and clinical course were analyzed according to the presence of IBD. RESULTS: Of the 82 patients, 25 (30.5%) had IBD and 57 (69.5%) did not have IBD. Hematochezia was more common in IBD patients (84.0% vs. 35.1%; p = .001), but fever and positive CMV antigenemia were more common in non-IBD patients (50.9% vs. 12.0%; p = .001; 54.4% vs. 28.0; p = .027). Endoscopic findings showed more ulcer with inflammation in IBD patients (68.0% vs. 35.2%; p = .005). Sixty-four patients were treated with antiviral agents and 12 patients who did not receive antiviral agents recovered spontaneously. All naturally healed patients were in normal immune status. CONCLUSIONS: Hematochezia is more common in IBD patients and fever/CMV antigenemia is more common in patients without IBD. In patients without IBD, the natural resolution of CMV enterocolitis is expected at least in normal immune function.

Cytomegalovirus Enterocolitis in Immunocompetent Young Children: A Report of Two Cases and Review of the Literature.

Cytomegalovirus (CMV) causes significant morbidity and mortality in congenitally infected children and immunocompromised hosts. Among healthy individuals, CMV is generally thought to cause mild, self-limited illness. CMV enterocolitis, in particular, is rarely considered among immunocompetent children presenting with diarrhea. We describe 2 cases of invasive CMV colitis in immunocompetent infants presenting with diarrhea and review the literature to date on this topic. Although invasive CMV enterocolitis has been sporadically reported among immunocompetent children, it remains an underrecognized cause of infectious diarrhea in this population and indications for antiviral therapy are lacking. We propose that CMV should be included in the differential diagnosis of intractable diarrhea in immunocompetent children.

Concurrent Acute Necrotizing Adenovirus Hepatitis and Enterocolitis in an Adult Patient After Double Cord Blood Stem Cell Transplant for Refractory Crohn's Disease.

It has been recently recognized that adenovirus is a pathogen with high morbidity and mortality among immunocompromised patients, particularly after solid organ or stem cell transplant. Confluent necrotizing hepatitis secondary to adenovirus infection alone or together with other organ involvement is extremely rare. There are only 32 cases of confluent necrotizing hepatitis reported in adults since 1960 and most occur after iatrogenic immunosuppression for bone marrow or solid organ transplantation or in other states of immunosuppression, including acquired immunodeficiency syndrome or chemotherapy treatment. We present the first case of concurrent adenovirus-induced necrotizing hepatitis and enterocolitis in an adult patient after double cord stem cell transplant for refractory Crohn's disease. Additionally, we report the imaging and morphologic findings and discuss the potential significance of morphology and immunohistochemistry as a practical approach for identifying adenovirus.

[ENHANCEMENT OF THE IMMUNE RESPONSE BY CO-DELIVERY OF THE HEPATITIS C VIRUS RECOMBINANT DNA AND PROTEINS OF REPLI- CATIVE COMPLEX GENETIC VARIANTS OF THE NOROVIRUS GENOTYPE GII.6].

BACKGROUND: Noroviruses--etiological agents of acute enteric infections, mainly related to the genotype GII.4. However, other genotypes of the noroviruses also play an important role in some epidemic seasons or in particular geographic regions. The norovirus genotype GII.6 has become the second most important etiologic agent of outbreaks of the norovirus infection after GII.4 in recent years. OBJECTIVE: To characterize the norovirus genotype GII.6 genetic variants based on phylogenetic analysis of genome sequences submitted to the databases GenBank and NoroNet as well as identified in Nizhny Novgorod. MATERIALS AND METHODS: Norovirus genotype GII.6 circulating with sporadic morbidity that had caused the outbreak of acute enteric infection in Nizhny Novgorod were identified by sequencing the region of the genome encoding the N/S-domain of capsid protein VP1. The comparative phylogenetic analysis of obtained sequences and sequences available in the international genetic databases was performed using the MEGA 5.2 software package. RESULTS: The presence of three genetic variants of the noroviruses GII.6 genotype based on capsid protein gene, GII.6a (Seacroft_1990), GII.6b (Saitama_1997) and GII.6c (Shizuoka 2008), in combination with two genotypes of the polymerase gene, P6 and P7, was confirmed. It was shown that co-circulation of these variants from the 1970s reflected the differences in evolution between the minor genotypes of noroviruses and dominant genotype GII.4, whose new epidemic variants completely replaced the previous for several years. Noroviruses GII.6 circulating in Nizhny Novgorod and other cities of Russia belong to genovariants GII.6a and GII.6b. CONCLUSION: The recombinant noroviruses GII.P7_GII.6c became most widespread in Asia and Europe in recent years. Genetic variant GII.6c of the norovirus have not been identified in Russia, but we cannot exclude the possibility of their occurrence as a cause of the outbreaks of acute enteric infections in this country in the near future.

Intractable diarrhoea caused by cytomegalovirus enterocolitis in an immunocompetent term neonate.

Symptomatic cytomegalovirus (CMV) infection mainly affects preterm and immunocompromised infants and usually manifest as rash, pneumonia, hepatospleenomegaly or encephalitis. To our knowledge intractable diarrhoea at two weeks of age caused by postnatally acquired CMV in immunocompetent term neonate is not reported. An unusual case of postnatally acquired CMV enterocolitis manifesting as protracted diarrhoea in an immunocompetent baby in neonatal period is reported. We conclude that CMV should be considered in the differential diagnosis of intractable diarrhoea in neonatal period and treatment with intravenous ganciclovir for CMV enterocolitis is not only indicated but is therapeutic.

Complete genome sequence of an astrovirus identified in a domestic rabbit (Oryctolagus cuniculus) with gastroenteritis.

A colony of domestic rabbits in Tennessee, USA, experienced a high-mortality (~90%) outbreak of enterocolitis. The clinical characteristics were one to six days of lethargy, bloating, and diarrhea, followed by death. Heavy intestinal coccidial load was a consistent finding as was mucoid enteropathy with cecal impaction. Preliminary analysis by electron microscopy revealed the presence of virus-like particles in the stool of one of the affected rabbits. Analysis using the Virochip, a viral detection microarray, suggested the presence of an astrovirus, and follow-up PCR and sequence determination revealed a previously uncharacterized member of that family. Metagenomic sequencing enabled the recovery of the complete viral genome, which contains the characteristic attributes of astrovirus genomes. Attempts to propagate the virus in tissue culture have yet to succeed. Although astroviruses cause gastroenteric disease in other mammals, the pathogenicity of this virus and the relationship to this outbreak remains to be determined. This study therefore defines a viral species and a potential rabbit pathogen.