Notes
H. Pylori, Campylobacter, Cholera
Sections
Overview of Gram-Negative Rods - Gastrointestinal illness (non-enterobacteriaceae)
Enterobacteriaceae, including E. coli, are discussed separately.
- Spiral rod-shaped bacterium; it can appear coccoid in older samples.
- Very common pathogen; present in about half the world's population.
- Colonization is life-long; introduction often occurs during childhood, though symptoms of infection occur later in adulthood.
- Bacterial carcinogen.
Pathology - Gastritis
– Inflammation of the stomach lining.
– Inflammation can be localized or widespread, and can affect the duodenum.
– Neutrophils infiltrate the mucosa. - Peptic ulcers
– Bacteria erode the mucosal lining of the stomach and/or duodenal. - Gastric adenocarcinoma
– Associated with chronic, widespread inflammation.
– Mucosal tissue is replaced by fibrous tissue and intestinal–type epithelium. - Gastric mucosa-associated lymphoid tissue B-cell lymphomas
– B-cells migrate to the stomach mucosa and establish lymphomas.
- Common causes of bacterial gastroenteritis.
– Also cause extra-intestinal infections. - Spiral rod-shaped but may appear coccoid in older specimens.
- Campylobacter jejuni
– Distinct histopathology, with ulcerated and bloody villi, white blood cell infiltration, and the formation of abscesses in the intestinal glands and crypts. - In some individuals, Campylobacter jejuni infection triggers immune-mediated disorders.
– Guillain-Barré syndrome occurs when the immune system targets the peripheral nervous system.
Patients experience tingling and ascending weakness; ultimately, impairment of inspiratory muscles can lead to respiratory failure.
– Reactive arthritis is characterized by joint pain and swelling.
Vibrio cholerae and Vibrio parahaemolyticus
Vibrio parahaemolyticus is also associated with wound infections.
- Consumed in contaminated food or water.
- Gastroenteritis caused by Vibrio species is characterized by watery diarrhea, cramps, vomiting, and nausea.
- Choleara
– Two strains of Vibrio cholerae are associated with cholera, which is a severe gastroenteritis that produces profuse watery diarrhea (sometimes referred to as "rice water" diarrhea).
– If untreated, Cholera can lead to fatal dehydration.