Entamoeba coli are intestinal amebae that are found in the large intestine. They generally are not considered pathogenic. However, when these amebae are found in stool samples it can indicate the presence of other potentially pathogenic organisms.

E. histolytica invasion may contribute to T-helper-2 bias and antibody production particularly against E. histolytica lectins and their association with tissue antigens such as phospholipids, actin and ANCA. By penetrating the intestinal tissues, E. histolytica is able to disturb tight junction assemblies, thereby opening the intestinal tight junctions and putting the body at risk for autoimmunity. Once in the bloodstream, E. histolytica may trigger autoimmunity against neurological or bone tissues, due to its homology with gangliosides and skeletal actin.

Entamoeba histolytica is a protozoan parasite that infects an estimated 34 to 50 million people per year worldwide, and kills 100,000 individuals annually. The disease caused by E. histolytica, amebiasis, is common in tropical areas with poor sanitary conditions but is also endemic in the US with the prevalence of E. histolytica infection estimated to be 4%. The most common clinical manifestation of infection with E. histolytica is amoebic diarrhea without dysentery; however, more severe cases can result in amoebic dysentery, which is diarrhea with mucous and visible or microscopic blood, severe abdominal pain, fever, and elevated fecal lysozyme. Occasional asymptomatic carriage is possible.

Entamoeba histolytica is a disease-causing parasite that can affect anyone, although it is more common in those who lived or travelled in tropical areas with poor sanitary conditions. Diagnosis can be difficult since, under a microscope, it looks similar to other parasites such as Entamoeba dispar and Entamoeba hartmanii. The latter two parasites generally do not cause illness.

Epidemiology:

→ Fecal contamination of ingested foods or water

→ Pets may be a source of exposure

→ Sexual contact may be a source of exposure

Clinical Implications:

→ Symptoms include diarrhea, fulminating colitis (resembling ulcerative colitis), and dysentery

→ Extreme cases may invade liver and lung tissues

Enteroaggregative Escherichia coli (EAEC) are quite heterogeneous category of an emerging enteric pathogen associated with cases of acute or persistent diarrhea worldwide in children and adults, and over the past decade has received increasing attention as a cause of watery diarrhea, which is often persistent. EAEC infection is an important cause of diarrhea in outbreak and non-outbreak settings in developing and developed countries. Recently, EAEC has been implicated in the development of irritable bowel syndrome, but this remains to be confirmed. 

E. cloaceae is a Gram-negative, nonspore-forming, enteric bacilli belonging to the Enterobacteriaceaefamily. Enterobacteriaceae are not considered primary human pathogens, but are capable of causing opportunistic infections.

Enterobacter have a ubiquitous environmental distribution (trees, plants, crops, soil, water, and foods). They are also part of the normal flora of the GI tract. It can also be a common nosocomial infection.

Enterobacter’s ability to form biofilms and to secrete various cytotoxins, such as enterotoxins and hemolysins, contribute to its pathogenicity.

Most patients with an E. cloaceae infection are asymptomatic. However, when present, symptoms can include nausea, vomiting, diarrhea, and abdominal cramps.

Enterobacter cloacae complex is part of the Enterobacteriaceae family. E cloacae complex is a group of six closely related species with similar resistance patterns:

E. cloacae, E. asburiae, E. hormaechei, E. kobei, E. ludwigii, and E. nimipressuralis.

Enterobacter is a genus of common Gram-negative, facultatively anaerobic, rod-shaped bacteria, commonly found in the environment as well as the gastrointestinal tract. There are many species, however, not all species are known to cause human disease.
Usually considered a commensal organism; however, strains of E.b cloacae have been shown to produce a heat-stable toxin similar to that produced by E.coli.