It is the primary facultative anaerobe of the human gastrointestinal tract. (Facultative anaerobes are organisms that can grow in either the presence or absence of oxygen.) As long as these bacteria do not acquire genetic elements encoding for virulence factors, they remain benign commensals. Therapeutic use
Due to the low cost and speed with which it can be grown and modified in laboratory settings, E. coli is a popular expression platform for the production of recombinant proteins used in therapeutics. One advantage to using E. coli over another expression platform is that E. coli naturally does not export many proteins into the periplasm, making it easier to recover a protein of interest without cross-contamination. The E. coli K-12 strains and their derivatives (DH1, DH5α, MG1655, RV308 and W3110) are the strains most widely used by the biotechnology industry. Nonpathogenic E. coli strain Nissle 1917 (EcN), (Mutaflor) and E. coli O83:K24:H31 (Colinfant)) are used as probiotic agents in medicine, mainly for the treatment of various gastrointestinal diseases, including inflammatory bowel disease. It is thought that the EcN strain might impede the growth of opportunistic pathogens, including Salmonella and other coliform enteropathogens, through the production of microcin proteins the production of siderophores. Role in disease
Most E. coli strains do not cause disease, naturally living in the gut, but virulent strains can cause gastroenteritis, urinary tract infections, neonatal meningitis, hemorrhagic colitis, and Crohns disease. Common signs and symptoms include severe abdominal cramps, diarrhea, hemorrhagic colitis, vomiting, and sometimes fever.
Dacryoadenitis is inflammation of the lacrimal glands. Symptoms
Swelling of the outer portion of the upper lid, with possible redness and tenderness
Pain in the area of swelling
Excess tearing or discharge
Swelling of lymph nodes in front of the ear

Complications
Swelling may be severe enough to put pressure on the eye and distort vision. Some patients first thought to have dacryoadenitis may turn out to have a malignancy of the lacrimal gland. Causes
Acute dacryoadenitis is most commonly due to viral or bacterial infection. Common causes include mumps, Epstein-Barr virus, staphylococcus, and gonococcus. Chronic dacryoadenitis is usually due to noninfectious inflammatory disorders. Examples include sarcoidosis, thyroid eye disease, and orbital pseudotumor. Diagnosis
Dacryoadenitis can be diagnosed by examination of the eyes and lids. Special tests such as a CT scan may be required to search for the cause. Sometimes biopsy will be needed to be sure that a tumor of the lacrimal gland is not present. Prevention
Mumps can be prevented by immunization. Gonococcus, bacteria can be avoided by the use of condoms. Most other causes cannot be prevented. Treatment
If the cause of dacryoadenitis is a viral condition such as mumps, simple rest and warm compresses may be all that is needed. For other causes, the treatment is specific to the causative disease. Prognosis
Most patients will fully recover from dacryoadenitis. For conditions with more serious causes, such as sarcoidosis, the prognosis is that of the underlying condition. References
External links

Source (NIH/Medline)
eMedicine
Diseases Database (DDB): 3430