Notes
Campylobacter
Sections
Spiral, gram-negative rods; may appear coccoid in older cultures.
Generally heat-resistant, and are cultured at 42 degrees Celsius (note that Campylobacter upsaliensis is an exception).
Grow in microaerobic conditions with relatively low oxygen levels and elevated carbon dioxide.
Oxidase positive.
Tiny, so they can be filtered from stool samples for diagnostic purposes.
Vulnerable to stomach acids; thus, illness is most common in individuals with reduced stomach acid production.
Zoonotic infections; that is, illness occurs after interactions with colonized animals.
Virulence factors:
Lipo-oligosaccharide endotoxin.
Polysaccharide capsule.
Flagella facilitate motility and invasion of host cells.
Cytolethal distending toxin is thought to cause cell death and IL-8 secretion. IL-8 is a pro-inflammatory cytokine that, when produced in excess, damages host tissues.
Infections:
Campylobacter species are the number one cause of bacterial gastroenteritis in the United States.
Gastroenteritis is characterized by watery, sometimes bloody, diarrhea with blood cells present in the stools; some individuals have fever.
Fortunately, the diarrhea is usually self-limited; illness lasts approximately six days.
In severe cases, or where complications arise, erythromycin or azithromycin can be administered.
Campylobacter jejuni
Primary pathogenic species; infection is associated with consumption of contaminated poultry and cow products.
Damages the mucosa of the jejunum, ileum, and colon:
Villus ulceration (can become bloody)
Neutrophils, eosinophils, and mononuclear cells invade the lamina propria
Abscesses form in the glands and crypts.
Infection can also cause bacteremia and cardiovascular dysfunction.
Post-infection complications:
Guillan-Barré syndrome is an autoimmune disorder that damages the myelin of the peripheral nervous system (hence it's a demyelinating disorder).
Individuals typically experience symmetrical weakness that begins in the lower extremities; weakness may ascend, and, in severe cases, can impair cardiovascular and respiratory functioning due to autonomic system involvement.
Blood pressure can swing wildly, so clinicians must be careful not to react too quickly to spikes in blood pressure or they can inadvertently cause devastating low blood pressures.
Early treatment with IVIG or plasmapheresis is important in management but most important is good supportive care while the illness runs its course, meaning early intubation, if respiratory distress is identified, and good nursing care to avoid superimposed infections.
Keys to diagnosing the disorder are:
Hyporeflexia (from the peripheral neuropathy).
CSF findings of cytoalbuminologic dissociation (meaning normal WBC but elevated protein)
EMG findings that may be normal early on but later show prolonged F Waves, conduction block, and eventually the demyelination (prolonged distal latencies and conduction velocities).
Acute Motor Axonal Neuropathy (AMAN) (GB variant, most common in China and Japan).
This variant actually affects the axons, themselves, rather than simply disruption of the myelin-coating of the nerve – and thus will demonstrate as an axonopathy on EMG.
Reactive arthritis is typically characterized by joint swelling and pain in the hands, knees, and ankles.
Campylobacter coli
Infection is associated with consumption of contaminated pork and poultry products.
It primarily causes gastroenteritis, but is also associated with some extra-intestinal infections.
Campylobacter upsaliensis
An emerging pathogen associated with cats and dogs; thus, outbreaks have been traced to pet stores.
It primarily causes gastroenteritis.
Has been associated with Guillain-Barré syndrome.
Campylobacter fetus
Infection primarily occurs in immunocompromised individuals.
Resistant to serum killing by antibodies and complement, thanks to the presence of S protein, which prevents C3b binding.
Bacteremia and septic thrombophlebitis (venous thrombosis with bacteremia)
Gastroenteritis
Be aware that this species was originally named Vibrio fetus.
Full-Length Text
Here we will learn about pathogenic strains of Campylobacter.
To begin, write that they are spiral, gram-negative rods; they may appear coccoid in older cultures.
They are generally heat-resistant, and are cultured at 42 degrees Celsius (note that Campylobacter upsaliensis is an exception).
They grow in microaerobic conditions with relatively low oxygen levels and elevated carbon dioxide.
They are oxidase positive.
Campylobacter bacteria are tiny, so they can be filtered from stool samples for diagnostic purposes.
They are vulnerable to stomach acids; thus, illness is most common in individuals with reduced stomach acid production.
And, they cause zoonotic infections; that is, illness occurs after interactions with colonized animals.
Next, indicate the following virulence factors:
Lipo-oligosaccharide endotoxin
A polysaccharide capsule
Flagella, which facilitate motility and invasion of host cells.
The exact roles of endotoxins and exotoxins have not been definitively defined, but, it is thought that cytolethal distending toxin causes cell death and IL-8 secretion. IL-8 is a pro-inflammatory cytokine that, when produced in excess, damages host tissues.
Now, let's consider infections caused by Campylobacter species.
First, write that they are the number one cause of bacterial gastroenteritis in the United States.
Campylobacter gastroenteritis is characterized by watery, sometimes bloody, diarrhea, with blood cells present in the stools; some individuals have fever.
Fortunately, the diarrhea is usually self-limited; illness lasts approximately six days.
In severe cases, or where complications arise, erythromycin or azithromycin can be administered.
Indicate that Campylobacter jejuni is the primary pathogenic species; infection is associated with consumption of contaminated poultry and cow products.
As its name implies, these bacteria damage the mucosa of the jejunum, ileum, and colon.
In a histological sample of the jejunum, label the villi, lamina propria, and intestinal glands and crypts.
Show that infection leads to ulceration of the villi, which can become bloody.
Neutrophils, eosinophils, and mononuclear cells invade the lamina propria.
Abscesses form in the glands and crypts.
Indicate that Campylobacter jejuni infection can also cause bacteremia and cardiovascular dysfunction.
Write that some individuals experience post-infection complications, including Guillan-Barré syndrome and reactive arthritis.
Show that Guillan-Barré syndrome is an autoimmune disorder that affects the peripheral nervous system.
Show that it damages the myelin of the peripheral nervous system (hence it's a demyelinating disorder).
Indicate that classically, patients experience symmetrical weakness that begins in the lower extremities and ascends to ultimately compromise the ability to breathe.
Draw the cardiovascular and respiratory systems because although the weakness is the most prominent finding, patients can also die from cardiopulmonary dysfunction from autonomic nervous system involvement.
The blood pressure can swing wildly and thus clinicians must be careful not to react too quickly to spikes in blood pressure or they can inadvertently cause devastating low blood pressures.
Indicate that early treatment with IVIG or plasmapheresis is important in management but most important is good supportive care while the illness runs its course, meaning early intubation, if respiratory distress is identified, and good nursing care to avoid superimposed infections.
Indicate that keys to diagnosing the disorder are:
Hyporeflexia (from the peripheral neuropathy).
CSF findings of cytoalbuminologic dissociation (meaning normal WBC but elevated protein)
EMG findings that may be normal early on but later show prolonged F Waves, conduction block, and eventually the demyelination (prolonged distal latencies and conduction velocities).
Note that campylobacter jejuni infection, itself, is actually associated with a particularly aggressive form of Guillain-Barre, called Acute Motor Axonal Neuropathy (AMAN) (it's most common in China and Japan).
As the name Acute Motor Axonal Neuropathy states, this variant actually affects the axons, themselves, rather than simply disruption of the myelin-coating of the nerve – and thus will demonstrate as an axonopathy on EMG.
Indicate that reactive arthritis is typically characterized by joint swelling and pain in the hands, knees, and ankles.
Next, indicate that Campylobacter coli infection is associated with consumption of contaminated pork and poultry products.
It primarily causes gastroenteritis, but is also associated with some extra-intestinal infections.
Campylobacter upsaliensis is an emerging pathogen associated with cats and dogs; thus, outbreaks have been traced to pet stores.
It primarily causes gastroenteritis, and, like Campylobacter jejuni, has been associated with Guillain-Barre syndrome.
Finally, indicate that Campylobacter fetus is associated with bacteremia and septic thrombophlebitis; show that septic thrombophlebitis is venous thrombosis with bacteremia.
Campylobacter fetus is also associated with the following:
Endocarditis, meningoencephalitis, and, gastroenteritis.
Infection primarily occurs in immunocompromised individuals.
Indicate that Campylobacter fetus is resistant to serum killing by antibodies and complement, thanks to the presence of S protein, which prevents C3b binding.
Be aware that this species was originally named Vibrio fetus.
References
Murray, P. R., Rosenthal, K. S., & Pfaller, M. A. Medical microbiology. Philadelphia: Elsevier/Saunders. (2013).
Levinson, W. E. Review of Medical Microbiology and Immunology. 14th Ed. Lange (2016)
Bezine, E., Vignard, J., Milrey, G. (2014). The cytolethal distending toxin effects on mammalian cells: A DNA damage perspective. Cells. 3:529-615.
Hermans, D., Pasmans, F., Messens, W., Martel, A., van Immerseel, F., Rasschaert, G., et al. (2012). Poultry as a host for the zoonotic pathogen Campylobacter jejuni. Vector-Borne and Zoonotic Diseases. 12(2): 89-99.
Kaakoush, N.O., Castano-Rodriguez, N., Mitchell, H.M., Mann, S.M. (2015). Global epidemiology of Campylobacter infection. Clinical Microbiology Reviews. 28(3): 687-720.
Dasti, J.I., Tareen, A.M., Lugert, R., Zautner, A.E., Growb, U. (2010). Campylobacter jejuni: a brief overview on pathogenicity-associated and disease-mediating mechanisms. International Journal of Medical Microbiology 300:205-211.
Images:
Vili (Mark Braun, MD. http://medsci.indiana.edu/c602web/602/c602web/toc.htm)
Campylobacter (Wikipedia; De Wood, Pooley, USDA, ARS, EMU. - Agricultural Research Service (ARS) is the U.S. Department of Agriculture's chief scientific research agency.)