Which Infections Are Caused by Gram Negative Bacteria?

Infections that are caused by gram negative bacteria include intestinal infections caused by the E. coli bacteria, peptic ulcers and Legionnaires' disease, according to Healthline, Mayo Clinic, Highveld and MedlinePlus. The plague is also caused by a gram negative bacteria.

E. coli bacteria often live harmlessly in the gut, but some strains, such as E. coli 0157:H7, cause illness, says Healthline. Symptoms of infection by this bacteria include cramping, watery diarrhea that can give way to bloody stool, nausea, gas and fever. These symptoms start between one and five days after the person is exposed to the bacteria and can progress to bloody urine, pallor, bruising and dehydration.

Peptic ulcers can be caused by the Helicobacter pylori bacteria, says Mayo Clinic. It does this by setting up an inflammation in the lining of the stomach. Medical experts are not sure how H. pylori spreads.

Legionnaires' disease is a type of pneumonia caused by the Legionella bacteria, says MedlinePlus. People get this disease by breathing in water droplets contaminated with the bacteria. The symptoms are similar to other kinds of pneumonia, and the risk of contracting the disease is greater in people over 50 years of age who smoke and who have compromised immune systems.

Fortunately, the plague can now be cured by a course of powerful antibiotics and intensive care, but it is still a life-threatening disease, says Healthline. It is caused by the Yersinia pestis bacteria.