Potgieter, N. | Search bioRxiv

bioRxiv2020

Enteropathogenic Escherichia coli (EPEC) Infection Induces Diarrhea, Intestinal Damage, Metabolic Alterations and Increased Intestinal Permeability in a Murine Model

Enteropathogenic E. coli (EPEC) are recognized as one of the leading bacterial causes of infantile diarrhea worldwide. Weaned C57BL/6 mice pretreated with antibiotics were challenged orally with wild-type EPEC or escN mutant (lacking type 3 secretion system) to determine colonization, inflammatory responses and clinical outcomes during infection. Antibiotic disruption of intestinal microbiota enabled efficient colonization by wild-type EPEC resulting in growth impairment and diarrhea. Increase in inflammatory biomarkers, chemokines, cellular recruitment and pro-inflammatory cytokines were observed in intestinal tissues. Metabolomic changes were also observed in EPEC infected mice with changes in TCA cycle intermediates, increased creatine excretion and shifts in gut microbial metabolite levels. In addition, by 7 days after infection, although weights were recovering, EPEC-infected mice had increased intestinal permeability and decreased colonic claudin-1 levels. The escN mutant colonized the mice, but had no weight changes or increased inflammatory biomarkers, showing the importance of the T3SS in EPEC virulence in this model. In conclusion, a murine infection model treated with antibiotics has been developed to mimic many clinical outcomes seen in children with EPEC infection and to examine potential roles of selected virulence traits. This model can help in further understanding mechanisms involved in the pathogenesis of EPEC infections and potential outcomes and thus assist in the development of potential preventive or therapeutic interventions.

microbiology↗

bioRxiv2019

HUMAN BOCAVIRUS PREVALENCE IN CHILDREN WITH ACUTE GASTROENTERITIS FROM RURAL COMMUNITIES IN THE NORTHEN REGION OF SOUTH AFRICA

BACKGROUNDAcute gastroenteritis (AGE) is a leading cause of morbidity and mortality in young children worldwide. Human Bocavirus (HBoV) is an emerging virus globally associated with diarrhea. The aim of this study was to demonstrate the prevalence of HBoV genotypes in children ([≤]5 years) from rural communities in South Africa (SA) suffering from AGE.\n\nMATERIAL AND METHODA total of 141 fecal samples of children [≤]5 years with acute gastroenteritis (AGE) were collected from rural Primary Health Care facilities in the Vhembe district of SA between June 2017 and July 2018. Clinical symptoms and demographic data were also recorded. A total of 102 (72%) were outpatients and 39 (28%) were hospitalized patients. Human Bocavirus (HBoV) genotypes were determined using Real-Time Multiplex PCR. DNA extracts of positive samples were confirmed by conventional PCR targeting the NS1 gene. Co-infection with other enteric viruses were determined in HBoV positive samples using Real-Time PCR.\n\nRESULTSHBoV was detected in 8 (5.7%) children with AGE. Children were in the age group between 1-24 months. HBoV1 and HBoV3 genotypes were each detected in 3 (37.5%) stool samples and HBoV2 in 2 (25%) stool samples. Co-infection with other enteric viruses included Rotavirus (37.5%); Adenovirus (37.5%); Norovirus (25%) and Astrovirus (12.5%).\n\nCONCLUSIONHBoV infections could be seen as a potential emerging diarrheal pathogen in South Africa. Further studies are required to understand the role of HBoV infections in children and adults with acute gastroenteritis.\n\nAuthor summaryAcute gastroenteritis (AGE) is recognized as a major cause for mortality in children [≤]5 years of age in Africa and other developing countries. Viruses known to be involved in AGE includes Rotavirus, Norovirus, Astrovirus and Adenovirus and have been reported globally. Recently the Human Bocavirus (HBoV) have been reported in numerous studies globally as a potential cause of diarrhea. In this study, the prevalence and genetic diversity of human Bocavirus in children with AGE from rural communities in Limpopo, South Africa were investigated. In total, 141 stool samples from children [≤] 5 years with AGE were assessed for the presence of HBoV using Real-Time PCR. HBoV were detected in 8 (5.7%) patients and included 3 positive samples for HBoV1 and HBoV3 respectively and 2 positive for HBoV2. No HBoV4 were detected. Among the 8 positive HBoV samples, co-infection with other enteric viruses were found in 7 (87.5%) samples, while mono infection with HBoV alone was detected in 1 (12.5%) patient. HBoV mixed infection with Rotavirus (3/8; 37.5%); Adenovirus (3/8; 37.5%); Norovirus (2/8; 25%) and Astrovirus (1/8; 12.5%) were observed in this study. This study reported for the first time on the prevalence of human Bocavirus in children with AGE from rural communities in South Africa.

microbiology↗