Intestinal Abnormalities in Patients With SARS-CoV-2 Infection: Histopathologic Changes Reflect Mechanisms of Disease.

Approximately 20% of patients with symptomatic syndrome-associated coronavirus-2 (SARS-CoV-2) infection have gastrointestinal bleeding and/or diarrhea. Most are managed without endoscopic evaluation because the risk of practitioner infection outweighs the value of biopsy analysis unless symptoms are life-threatening. As a result, much of what is known about the gastrointestinal manifestations of coronavirus disease-2019 (COVID-19) has been gleaned from surgical and autopsy cases that suffer from extensive ischemic injury and/or poor preservation. There are no detailed reports describing any other gastrointestinal effects of SARS-CoV-2 even though >3,000,000 people have died from COVID-19 worldwide. The purpose of this study is to report the intestinal findings related to SARS-CoV-2 infection by way of a small case series including one with evidence of direct viral cytopathic effect and 2 with secondary injury attributed to viral infection. Infection can be confirmed by immunohistochemical stains directed against SARS-CoV-2 spike protein, in situ hybridization for spike protein-encoding RNA, and ultrastructural visualization of viruses within the epithelium. It induces cytoplasmic blebs and tufted epithelial cells without inflammation and may not cause symptoms. In contrast, SARS-CoV-2 infection can cause gastrointestinal symptoms after the virus is no longer detected, reflecting systemic activation of cytokine and complement cascades rather than direct viral injury. Reversible mucosal ischemia features microvascular injury with hemorrhage, small vessel thrombosis, and platelet-rich thrombi. Systemic cytokine elaboration and dysbiosis likely explain epithelial cell injury that accompanies diarrheal symptoms. These observations are consistent with clinical and in vitro data and contribute to our understanding of the protean manifestations of COVID-19.

Bowel Ischemia in COVID-19 Infection: One-Year Surgical Experience.

BACKGROUND: COVID-19 is a deadly multisystemic disease, and bowel ischemia, the most consequential gastrointestinal manifestation, remains poorly described. Our goal is to describe our institution's surgical experience with management of bowel ischemia due to COVID-19 infection over a one-year period. METHODS: All patients admitted to our institution between March 2020 and March 2021 for treatment of COVID-19 infection and who underwent exploratory laparotomy with intra-operative confirmation of bowel ischemia were included. Data from the medical records were analyzed. RESULTS: Twenty patients were included. Eighty percent had a new or increasing vasopressor requirement, 70% had abdominal distension, and 50% had increased gastric residuals. Intra-operatively, ischemia affected the large bowel in 80% of cases, the small bowel in 60%, and both in 40%. Sixty five percent had an initial damage control laparotomy. Most of the resected bowel specimens had a characteristic appearance at the time of surgery, with a yellow discoloration, small areas of antimesenteric necrosis, and very sharp borders. Histologically, the bowel specimens frequently have fibrin thrombi in the small submucosal and mucosal blood vessels in areas of mucosal necrosis. Overall mortality in this cohort was 33%. Forty percent of patients had a thromboembolic complication overall with 88% of these developing a thromboembolic phenomenon despite being on prophylactic pre-operative anticoagulation. CONCLUSION: Bowel ischemia is a potentially lethal complication of COVID-19 infection with typical gross and histologic characteristics. Suspicious clinical features that should trigger surgical evaluation include a new or increasing vasopressor requirement, abdominal distension, and intolerance of gastric feeds.

Bowel necrosis in patient with severe case of COVID-19: a case report.

BACKGROUND: In patients who are critically ill with COVID-19, multiple extrapulmonary manifestations of the disease have been observed, including gastrointestinal manifestations. CASE PRESENTATION: We present a case of a 65 year old man with severe COVID-19 pneumonia that developed hypercoagulation and peritonitis. Emergent laparotomy was performed and we found bowel necrosis in two sites. CONCLUSIONS: Although rare, the presentation of COVID-19 with bowel necrosis requires emergency treatments, and it has high mortality rate.

Ileocolic Intussusception as the Presenting Symptom of Primary Enteric Varicella-Zoster Virus Infection in a 7-Month-Old Infant.

Ileocolic intussusception is the invagination of ileum into the colon. In a subset of patients, the disease is caused by mesenteric lymphadenopathy in response to (viral) infection. We present a case of an ileocolic intussusception necessitating surgery in a 7-month-old immunocompetent infant with concurrent primary wild-type varicella-zoster virus (VZV) infection, in whom chickenpox rash developed 2 days after surgery. Detailed in situ analyses of resected intestine for specific cell type markers and VZV RNA demonstrated VZV-infected lymphocytes and neurons in the gut wall and in ganglion cells of the myenteric plexus.

High prevalent human papillomavirus infections of the oral cavity of asymptomatic HIV-positive men.

BACKGROUND: Incidence of anal and oral infections with Human Papillomavirus (HPV) is increasing, particularly among Human Immunodeficiency Virus-positive (HIV+) men. HPV type 16 has exhibited the highest incidence and only limited data is available on other prevalent types, variants of HPV16, as well as associated factors. We were interested in identifying prevalent HPV types, variants of type 16, as well as factors associated with HPV16 infections in the oral cavity of HIV+ men who have sex with men (MSM). METHODS: A cross-sectional study of oral cavity samples from HIV+ MSM, that in a previous study were identified as positive for HPV16 in the anal canal. Cells from the oral cavity (102 samples, paired with 102 from the anal canal of same patient) were used to extract DNA and detect HPV infections using INNO-LiPA HPV Genotyping Extra II, and PCR. From these, 80 samples (paired, 40 anal and 40 oral) were used to identify variants of type 16 by sequencing. Statistical differences were estimated by the X2 test, and p values equal to or less than 0.05 were considered significant. SPSS ver. Twenty-four statistical software (IBM Corp) was used. RESULTS: We found a high prevalence of High-Risk HPV (HR-HPV) and Low-Risk HPV (LR-HPV). Patients were positive in the oral cavity for HR types; 16, 39 and 18 (80.4, 61.8 and 52.9% respectively) and LR types 11 and 6 (53.9 and 34.3% respectively). Surprisingly, only European variants of type 16 were found in the oral cavity, although American Asian (22.5%) and African (2.5%) variants were identified in the anal canal. The analysis showed that CD4 counts could be the most important risk factor associated with HR-HPV infections in the oral cavity, anal canal or both anatomical regions. The risk of infection of the oral cavity with type 18 increased in men diagnosed with HIV for more than 6 years. CONCLUSIONS: Prevalence of both HR and LR HPV's in the oral cavity of Mexican HIV+ MSM is very high. The fact that only European variants of HPV16 were found in the oral cavity suggest a possible tropism not previously described.

Systemic DPP4 activity is reduced during primary HIV-1 infection and is associated with intestinal RORC+ CD4+ cell levels: a surrogate marker candidate of HIV-induced intestinal damage.

INTRODUCTION: Combined anti-retroviral therapy (cART) transformed HIV-1 from a deadly disease into a chronic infection, but does not cure HIV infection. It also does not fully restore HIV-induced gut damage unless administered extremely early after infection. Additional biomarkers are needed to evaluate the capacity of therapies aimed at HIV remission/cure to restore HIV-induced intestinal immune damage and limit chronic inflammation. Herein, we aimed to identify a systemic surrogate marker whose levels would reflect gut immune damage such as intestinal Th17 cell loss starting from primary HIV-1 infection. METHODS: Biomarker discovery approaches were performed in four independent cohorts, covering HIV-1 primary and chronic infection in 496 naïve or cART-treated patients (Amsterdam cohort (ACS), ANRS PRIMO, COPANA and CODEX cohorts). The concentration and activity of soluble Dipeptidylpeptidase 4 (sDPP4) were quantified in the blood from these patients, including pre- and post-infection samples in the ACS cohort. For quantification of DPP4 in the gut, we utilized two non-human primate models, representing pathogenic (macaque) and non-pathogenic (African green monkey) SIV infection. Four gut compartments were analysed in each animal model (ileum, jejunum, colon and rectum) for quantification of DPP4, RORC and TBX21 gene expression in sorted CD4+ cells. To analyse if sDPP4 levels increase when Th17 cells were restored, we quantified sDPP4 in plasma from SIV-infected macaques treated with IL-21. RESULTS: We showed that sDPP4 levels were strongly decreased in primary HIV-1 infection. Strikingly, sDPP4 levels in primary HIV-1 infection predicted time to AIDS. They were not increased by cART in chronic HIV-1 infection (median 36 months on cART). In the gut of SIV-infected non-human primates, DPP4 mRNA was higher in CD4+ than CD4- leucocytes. DPP4 specifically correlated with RORC expression, a Th17 marker, in CD4+ cells from the intestine. We further demonstrated that sDPP4 activity levels were increased in animals treated with IL-21 and that this increase was associated with restoration of the Th17 compartment and reduced inflammation. Furthermore, DPP4 mRNA levels in small intestine CD4+ cells positively correlated with circulating DPP4 activity. CONCLUSION: These data provide evidence that blood sDPP4 levels could be useful as a correlate for HIV-induced intestinal damage.

[Polvomaviruses as causative agents of diseases]. / Polyoomavirukset sairauksien aiheuttajina.

The number of polyomaviruses causing infections in humans is as high as thirteen. The BK and JC polyomaviruses and the diseases caused by them are best known. For the present, the Merkel cell polyomavirus is the only human polyomavirus considered to be a causative agent of cancer. Other disease associations of polyomaviruses are also subject to active research. All polyomavirus infections are usually harmless respiratory or intestinal infections of childhood. Polyomaviruses, remain in the body for the rest of life, i.e. they persist as part of the body microbiome. Upon weakening of cell-mediated immunity they can also become reactivated and cause clinical problems.

Viral immunity. Transkingdom control of viral infection and immunity in the mammalian intestine.

Viruses that infect the intestine include major human pathogens (retroviruses, noroviruses, rotaviruses, astroviruses, picornaviruses, adenoviruses, herpesviruses) that constitute a serious public health problem worldwide. These viral pathogens are members of a large, complex viral community inhabiting the intestine termed "the enteric virome." Enteric viruses have intimate functional and genetic relationships with both the host and other microbial constituents that inhabit the intestine, such as the bacterial microbiota, their associated phages, helminthes, and fungi, which together constitute the microbiome. Emerging data indicate that enteric viruses regulate, and are in turn regulated by, these other microbes through a series of processes termed "transkingdom interactions." This represents a changing paradigm in intestinal immunity to viral infection. Here we review recent advances in the field and propose new ways in which to conceptualize this important area.

Increased Sensitivity to Binge Alcohol-Induced Gut Leakiness and Inflammatory Liver Disease in HIV Transgenic Rats.

The mechanisms of alcohol-mediated advanced liver injury in HIV-infected individuals are poorly understood. Thus, this study was aimed to investigate the effect of binge alcohol on the inflammatory liver disease in HIV transgenic rats as a model for simulating human conditions. Female wild-type (WT) or HIV transgenic rats were treated with three consecutive doses of binge ethanol (EtOH) (3.5 g/kg/dose oral gavages at 12-h intervals) or dextrose (Control). Blood and liver tissues were collected at 1 or 6-h following the last dose of ethanol or dextrose for the measurements of serum endotoxin and liver pathology, respectively. Compared to the WT, the HIV rats showed increased sensitivity to alcohol-mediated gut leakiness, hepatic steatosis and inflammation, as evidenced with the significantly elevated levels of serum endotoxin, hepatic triglycerides, histological fat accumulation and F4/80 staining. Real-time PCR analysis revealed that hepatic levels of toll-like receptor-4 (TLR4), leptin and the downstream target monocyte chemoattractant protein-1 (MCP-1) were significantly up-regulated in the HIV-EtOH rats, compared to all other groups. Subsequent experiments with primary cultured cells showed that both hepatocytes and hepatic Kupffer cells were the sources of the elevated MCP-1 in HIV-EtOH rats. Further, TLR4 and MCP-1 were found to be upregulated by leptin. Collectively, these results show that HIV rats, similar to HIV-infected people being treated with the highly active anti-retroviral therapy (HAART), are more susceptible to binge alcohol-induced gut leakiness and inflammatory liver disease than the corresponding WT, possibly due to additive or synergistic interaction between binge alcohol exposure and HIV infection. Based on these results, HIV transgenic rats can be used as a surrogate model to study the molecular mechanisms of many disease states caused by heavy alcohol intake in HIV-infected people on HAART.

Intestinal cytomegalovirus infection in patients hospitalized for exacerbation of inflammatory bowel disease: a 10-year tertiary referral center experience.

OBJECTIVES: This 10-year retrospective cohort study aims to determine the prevalence and risk factors of cytomegalovirus (CMV) infection in inpatients with exacerbated inflammatory bowel disease (IBD). METHODS: All patients admitted to the Department of Gastroenterology of the University Hospital Heidelberg for IBD exacerbation between January 2004 and June 2013 were enrolled. To identify the risk factors of CMV infection, infected individuals were compared with those with excluded infection. RESULTS: Among 297 patients with exacerbated IBD, 21 had confirmed CMV infection and 79 had excluded CMV infection, whereas the remaining patients had not been sufficiently tested for CMV. Taking into account only sufficiently tested individuals, the prevalence of CMV infection was 22.7% in ulcerative colitis and 16.0% in Crohn's disease. The occurrence of CMV infection was associated with the following variables at admission: age of 30 years or more [odds ratio (OR) 14.29; P=0.004], disease duration less than 60 months (OR 7.69; P=0.011), a blood leukocyte count less than 11/nl (OR 4.49; P=0.041), and immunosuppressive therapy (OR 6.73; P=0.0129). CMV-positive patients remained in the hospital longer than noninfected patients (P=0.0009). In the CMV-positive cohort, a 66-year-old woman died of CMV pneumonia and sepsis, whereas there was no death in the CMV-negative cohort. CONCLUSION: Immunuosuppressive therapy and age older than 30 years were identified as the main risk factors for the development of CMV infection in exacerbated IBD. Because of the risk of death, diagnostics of CMV infection should especially be initiated in older patients on immunosuppressive therapy.

Enteropathogensddetected in a daycare center, sutheastern Brazil: bacteria, viirus, and parasite research / Enteropatógenos detectados em crianças de creche no Sudeste do Brasil: pesquisa de bactérias, vírus e parasitos

Introduction: The objective of this study was to determine the prevalence and etiological profile of enteropathogens in children from a daycare center. Methods: From October 2010 to February 2011 stool samples from 100 children enrolled in a government daycare center in the municipality of São José do Rio Preto, in the state of São Paulo, were collected and analyzed. Results: A total of 246 bacteria were isolated in 99% of the fecal samples; 129 were in the diarrheal group and 117 in the non-diarrheal group. Seventy-three strains of Escherichia coli were isolated, 19 of Enterobacter, one of Alcaligenes and one of Proteus. There were 14 cases of mixed colonization with Enterobacter and E. coli. Norovirus and Astrovirus were detected in children with clinical signs suggestive of diarrhea. These viruses were detected exclusively among children residing in urban areas. All fecal samples were negative for the presence of the rotavirus species A and C. The presence of Giardia lamblia, Entamoeba coli, Endolimax nana and hookworm was observed. A significant association was found between food consumption outside home and daycare center and the presence of intestinal parasites. Conclusions: For children of this daycare center, intestinal infection due to pathogens does not seem to have contributed to the occurrence of diarrhea or other intestinal symptoms. The observed differences may be due to the wide diversity of geographical, social and economic characteristics and the climate of Brazil, all of which have been reported as critical factors in the modulation of the frequency of different enteropathogens.

Introdução: O objetivo deste estudo foi determinar a prevalência e o perfil etiológico de enteropatógenos em crianças de uma creche. Métodos: No período de outubro de 2010 a fevereiro de 2011 foram coletadas e analisadas amostras de fezes de 100 crianças matriculadas em creche do governo no município de São José do Rio Preto, Estado de São Paulo. Resultados: Um total de 246 bactérias foram isoladas em 99% das amostras de fezes; 129 eram diarreicas e 117 não-diarreicas. Foram isoladas setenta e três cepas de Escherichia coli, 19 de Enterobacter, uma de Alcaligenes e uma de Proteus. Foram detectados 14 casos de colonização mista com Enterobacter e de E. coli. Norovírus e Astrovirus foram detectados em crianças com sinais clínicos sugestivos de diarréia. Estes vírus foram detectados exclusivamente entre as crianças residentes em áreas urbanas. Todas as amostras fecais foram negativas para a presença das espécies de rotavírus A e C. Foi observada a presença de Giardia lamblia, Entamoeba coli, Endolimax nana e ancilostomídeos. Foi encontrada associação significativa entre o consumo de alimentos fora do centro da casa e creche e a presença de parasitos intestinais. Conclusões: Para as crianças desta creche, a infecção intestinal por patógenos não parece ter contribuido para a ocorrência de diarreia ou outros sintomas intestinais. As diferenças observadas podem ser atribuídas à grande diversidade de características geográficas, sociais e econômicas e o clima do Brasil, as quais tem sido relatadas como fatores críticos para a modulação da frequência de diferentes enteropatógenos.

The role of chronic norovirus infection in the enteropathy associated with common variable immunodeficiency.

OBJECTIVES: A severe enteropathy of unknown etiology can be associated with common variable immunodeficiency (CVID). METHODS: S tool and archived small intestinal mucosal biopsies from patients with CVID enteropathy were analyzed by PCR for the presence of Norovirus RNA. The PCR products were sequenced to determine the relationship of viral isolates. Stool samples from 10 patients with CVID but no enteropathy served as controls. RESULTS: All eight patients in our CVID cohort with enteropathy showed persistent fecal excretion of Norovirus. Analysis of archived duodenal biopsies revealed a strong association between the presence of Norovirus and villous atrophy over a period of up to 8 years. Analysis of the viral isolates from each patient revealed distinct strains of genogroup II.4. Sequence analysis from consecutive biopsy specimens of one patient demonstrated persistence of the same viral strain over a 6-year period. CVID patients without enteropathy showed no evidence of Norovirus carriage. Viral clearance occurred spontaneously in one patient and followed oral Ribavirin therapy in two further patients, and resulted in complete symptomatic and histological recovery. However, Ribavirin treatment in two further patients was unsuccessful. CONCLUSIONS: Norovirus is an important pathogen for patients with CVID and a cause of CVID enteropathy, as viral clearance, symptom resolution, and histological recovery coincide. Ribavirin requires further evaluation as a potential therapy.

Viral PCR positivity in stool before allogeneic hematopoietic cell transplantation is strongly associated with acute intestinal graft-versus-host disease.

Acute graft-versus-host disease (aGVHD) can be triggered by inflammatory conditions, including infections and mucositis. We investigated the association between PCR positivity for gastrointestinal (GI) viruses in stool before hematopoietic cell transplantation (HCT) and intestinal aGVHD using Cox proportional hazard models. We included 48 consecutive HCT patients (28 with malignancies and 20 with nonmalignancies) without GI symptoms before HCT. Fifteen patients were GI virus positive: 9 adenovirus, 3 norovirus, 2 parechovirus, and 1 astrovirus. Overall survival was 58% ± 8%. The cumulative incidence of aGVHD grade 2 to 4 was 43% ± 8% (n = 18) after a median of 47 days (range, 14 to 140). In univariate analysis, GI virus PCR positivity was the only predictor for aGVHD (P = .008): within the group of GI virus PCR-positive patients, the cumulative incidence of aGVHD 2 to 4 was 70% ± 12% versus 29 ± 8% in the PCR-negative group (P = .004). In conclusion, GI virus PCR positivity before HCT predicted development of intestinal aGVHD. These results may ultimately affect monitoring, aGVHD prophylaxis, and treatment, as well as rescheduling of elective HCTs.

[WASTE WATERS AS THE RESERVOIR OF INTESTINAL ENTERIC VIRAL INFECTIONS].

In the paper there are presented data of field observations of the spectrum of viruses, contained in the waste waters. The studies were performed on the territory of the city and the territory unfavorable for hepatitis A. In the territory of the big city by RT-PCR in the waste liquid the enterovirus RNA was detected in 45% of samples; astroviruses--90%; noroviruses--80% and 15% of rotaviruses. Samples from 2 wells were slightly positive for the presence of HCV RNA A. In the waste liquid on the territory, unfavorable for viral hepatitis A, in 100% of the samples there were determined noro- and astroviruses RNA and adenovirus DNA, in 75%--enterovirus RNA; 50%--HAV RNA and a 25%--rotavirus RNA.

Detection of cytomegalovirus (CMV) by real-time PCR in fecal samples for the non-invasive diagnosis of CMV intestinal disease.

BACKGROUND: Cytomegalovirus (CMV) infection of the gastrointestinal tract can cause CMV intestinal disease (CMV-ID), a severe complication in immunocompromised patients. Current gold standard for diagnosing CMV-ID requires the analysis of colon biopsies. Testing of fecal samples by CMV PCR might be a non-invasive diagnostic alternative, but data on this method is scarce. OBJECTIVES: To evaluate the use of quantitative CMV real-time PCR in fecal samples for diagnosing CMV-ID. STUDY DESIGN: Fecal samples and lower intestinal tract biopsies from 66 patients were analyzed by quantitative CMV PCR. To evaluate the diagnostic significance of CMV detection by PCR in fecal samples, patients were classified according to the etiology of their intestinal disease (based on results of endoscopy, histopathology and quantitative CMV DNA detection in biopsies) into three groups: "CMV-ID", "non-CMV-ID", and "equivocal". RESULTS: 10/66 fecal samples were tested positive by quantitative CMV PCR, but CMV DNA loads were low (range <1000-11,000copies/ml). CMV detection by PCR in fecal samples was positive in 8/12 patients of the CMV-ID group, resulting in a sensitivity of 67% for diagnosing CMV-ID. With two exceptions, fecal CMV PCR was negative in the non-CMV-ID group (45/47) indicating a good specificity (96%). Moreover, CMV DNA detection in feces was associated with high CMV DNA levels in intestinal biopsies. CONCLUSIONS: Negative CMV PCR results from fecal samples cannot exclude CMV-ID and thus have to be confirmed by analyzing intestinal biopsies. However, positive fecal PCR results are diagnostically useful and might help to circumvent invasive diagnostic procedures as endoscopy.

[The experimental evaluation of the possibility of the penetration of enteric viruses from the surface into the pulp of contaminated fruits and vegetables].

According to the results of complex microbiological examination of samples of vegetables, fruits and grapes there was established significant contamination of them with opportunistic bacteria, antigens of intestinal viruses and cysts of intestinal Protozoa, that confirms the epidemiological role of these products as factors in transmission of acute intestinal infections. There was revealed ribonucleic acid of enteric viruses in experimentally infected pulp from the surface of tomatoes and apples, that indicates to the possibility of penetration of these pathogens into the fruits and vegetables through intact (having no visible damages) surface.

Cytomegalovirus infection presenting as isolated inflammatory polyps of the gastrointestinal tract.

BACKGROUND: Gastrointestinal involvement by cytomegalovirus (CMV) infection is a well recognised complication in patients taking steroid/immunosuppressive therapy or suffering from immunodeficiency and debilitating diseases. Rarely, CMV may affect immunocompetent healthy individuals. However, CMV infection presenting as isolated inflammatory polyps is unusual. METHODS: We describe five patients (1 infant and 4 adults 56-80 years of age) with CMV-associated polyps that posed diagnostic difficulty. Four lesions were initially misdiagnosed as inflammatory fibroid polyp (n = 2), atypical/suspicious lymphoproliferative (n = 1) and mesenchymal (n = 1) lesion. RESULTS: Underlying diseases were kidney transplantation (1), ulcerative colitis (1), and HIV infection (1). One elderly patient had pseudomembranous colitis but no significant co-morbidity. One patient had no relevant diseases. The lesions affected the colon (3), small intestine (1) and gastric antrum (1); one was multifocal. The size ranged from 0.3 cm to 2.0 cm. Histologically, all lesions showed extensive surface ulceration and abundant capillary-rich granulation tissue containing activated lymphoid cells, plasma cells, granulocytes, enlarged histiocytes and atypical fibroblasts. Eosinophils were prominent in two cases. Immunohistochemistry showed unequivocal intranuclear CMV inclusions. CONCLUSION: These cases widen the spectrum of endoscopic and histological appearance of gastrointestinal CMV infection. Awareness of these unusual lesions should enhance detection and proper classification of this probably under-recognised CMV presentation.

Enteric pathology and Salmonella-induced cell death in healthy and SIV-infected rhesus macaques.

The goal of this study was to morphologically characterize a ligated ileal loop model of Salmonella enterica serotype Typhimurium infection in rhesus macaques (Macaca mulatta) and to verify the occurrence of Salmonella-induced cell death in vivo. Eight adult healthy male rhesus macaques were used for ligated ileal loop surgery. Four macaques had been intravenously inoculated with simian immunodeficiency virus (SIV) mac251. Ileal ligated loops were inoculated with wild-type (WT) S. Typhimurium strain IR715 (ATCC14028 nal (r)), an isogenic noninvasive mutant strain (ATCC14028 nal (r) ΔsipAΔsopABDE2), or sterile Luria Bertani broth. Loops were surgically removed at 2, 5, and 8 hours post-inoculation (hpi). Intestinal samples were processed for histopathology, immunohistochemistry for detecting Salmonella, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), and transmission electron microscopy. Combined histopathology scores were similar between SIV-infected and control macaques. As expected, the invasion-deficient mutant was less pathogenic than WT S. Typhimurium. Neutrophil infiltrate in the intestinal mucosa correlated with bacterial loads (r = 0.7148; P < .0001) and fluid accumulation (r = 0.6019; P < .0001) in the lumen of the intestinal loops. Immunolabeled WT S. Typhimurium was observed in the epithelium and lamina propria at the tip of the villi at 2 hpi, progressing toward deeper lamina propria at 5-8 hpi. Most TUNEL-positive cells localized to the lamina propria, and some had morphological features of macrophages. Ultrastructurally, bacteria were observed intracellularly in the lamina propria as well as within apoptotic bodies. This study provides morphological evidence of Salmonella-induced cell death in vivo in a relevant nonhuman primate model.

Quantification of cytomegalovirus DNA levels in intestinal biopsies as a diagnostic tool for CMV intestinal disease.

BACKGROUND: CMV intestinal disease (CMV-ID) is a serious complication in immunocompromised patients and mainly diagnosed by clinical, endoscopic and histopathologic findings, whereas qualitative CMV-PCR in tissue samples is not recommended for diagnosis due to its low positive predictive value (PPV). OBJECTIVES: To study the interpretation and diagnostic use of CMV-quantification by PCR in intestinal tissue biopsies to recognize CMV-ID. To develop cut-off intestinal CMV-loads attributing illness to CMV. STUDY DESIGN: CMV-genome copies in 163 biopsies from the lower intestinal tract of immunocompromised patients were determined by quantitative real-time PCR, normalized to the cell number, and retrospectively compared to histopathological analysis, clinical findings and occurrence of CMV-antigenemia. Two cut-off intestinal CMV-loads, cut-off(histo) and cut-off(clin), were defined using histopathological or clinical criteria as gold standard, respectively. RESULTS: CMV was detected in 32.5% of biopsies with a more than six log range of CMV-concentrations (1 x 10(-4)-1.4 x 10(2)copies/cell). Notably, biopsies with histopathologically or clinically confirmed CMV-ID had a significantly higher CMV-load (p<0.001). Cut-off(histo) and cut-off(clin) were defined at the intestinal CMV-load of 0.14 and 0.01 copies/cell, respectively, and improved the PPV. However, cut-off(histo) showed a decreased sensitivity for clinically defined CMV-ID cases. Interestingly, many patients with CMV-ID showed no concomitant CMV-antigenemia, suggesting a localized intestinal CMV-replication. CONCLUSIONS: Quantification of CMV in intestinal biopsies is a useful diagnostic tool allowing the definition of cut-off values that can predict CMV-ID more accurate than qualitative PCR results. Further prospective studies have to clarify wether these cut-offs can improve diagnostics and treatment of CMV-ID in day-to-day clinical practice.