Campylobacter & Helicobacter Flashcards
What are the general characteristics of Campylobacter spp.?
Nonspore forming, curved gram-negative bacilli, oxidase positive, motile, microaerophilic, nonfermentative.
Shows an “S” shaped or “seagull winged” appearance and has darting motility in wet preparations.
What are three common species of Campylobacter?
- Campylobacter jejuni subsp. jejuni
- Campylobacter fetus subsp. fetus
- Campylobacter coli
Which class do Neisseria species belong to?
Proteobacteria
What is the pathogenicity of Neisseria gonorrhoeae and Neisseria meningitidis?
Neisseria gonorrhoeae is always pathogenic; Neisseria meningitidis can be a commensal inhabitant of the upper respiratory tract.
What is the most common cause of bacterial gastroenteritis worldwide?
Campylobacter jejuni
How does Campylobacter jejuni typically enter the human body?
Through dirty drinking water or undercooked meat, especially chicken.
What are the typical symptoms of gastroenteritis caused by C. jejuni?
- Fever
- Abdominal pain
- Cramping
- Diarrhea (may contain blood or pus)
What is the incubation period for symptoms after ingesting contaminated food or drink containing C. jejuni?
2-10 days
What is the typical Gram stain morphology of C. jejuni?
Curved Gram-negative rod with a ‘seagull’ winged appearance.
What is the optimal temperature for growing thermophilic Campylobacter spp.?
42ºC
What media is used for Campylobacter culture?
- Campy BAP
- Modified Skirrow Media
- Campylobacter Medium (Karmali)
What type of environment is required for culturing Campylobacter organisms?
Microaerophilic environment with a gas mixture of 5-10% O2, 10% CO2, and 80-85% N2.
What is suggested by the presence of blood or pus in stools caused by C. jejuni?
An invasive mechanism, as C. jejuni produces exotoxins with cytolytic activity.
True or False: C. jejuni infection is usually self-limiting.
True
Fill in the blank: The Gram staining results for C. jejuni are better when _______ is used instead of safranin.
carbolfuchsin
What is the maximum time after stool passage that fresh specimens should be used for culture of Campylobacter spp.?
Less than 2 hours
What is the appearance of C. jejuni colonies on blood agar?
Red under colonies due to production of cytochromes.
What are the components of Campy BAP used in Campylobacter culture?
- Brucella blood agar base
- 10% sheep blood
- Vancomycin
- Trimethoprim
- Polymyxin B
- Amphotericin B
- Cephalothin
What is the incubation time and temperature for culturing C. fetus?
Incubated at 37ºC under microaerophilic conditions for at least 72 hours.
What are common methods to create a microaerophilic environment for Campylobacter culture?
- Campy Gas Packs
- Evacuation-Replacement
- BIOBAG
- Buddy Bags
Which class do Alysiella, CDC EF 4a and b, Acinetobacter, and Moraxella species belong to?
Proteobacteria
What is the morphology and biochemistry of Moraxella catarrhalis similar to?
Neisseria species
Is Neisseria gonorrheae always pathogenic or commensal?
Always pathogenic
Can Neisseria meningitidis be a commensal inhabitant?
Yes, in the upper respiratory tract of carriers
What is the colonial morphology of Campylobacter jejuni?
Moist, ‘runny-looking’, spreading, nonhemolytic colonies
What are some characteristics of suspicious colonies of Campylobacter spp. for presumptive identification?
- Catalase positive
- Oxidase positive
- Nitrate positive
- Darting motility
- Curved Gram-negative bacilli
What is the treatment for intestinal campylobacteriosis?
Erythromycin
What are the general characteristics of Helicobacter spp.?
- Gram-negative
- Microaerophilic
- Motile
- Catalase positive
- Oxidase positive
What is the leading cause of peptic ulcers and chronic gastritis?
H. pylori
What is the clinical picture associated with H. pylori infection?
- Low grade inflammatory process
- Chronic superficial gastritis
- Major cause of ulcers
- Risk factor for gastric carcinoma
What type of specimens are used for the culture of H. pylori?
Gastric biopsies
What does the Gram stain of a homogenized biopsy of H. pylori show?
Small, curved Gram-negative bacilli
What media is used for recovering H. pylori?
- Chocolate agar
- Selective medium such as Skirrow
What are the characteristics for presumptive identification of H. pylori?
- Small colonies growing microaerophilically
- Curved Gram-negative bacilli
- Catalase positive
- Oxidase positive
- Positive rapid urease test
What is the rapid urea breath test used for?
Detecting the presence of H. pylori
What is a noninvasive procedure for detecting H. pylori?
Rapid urea breath test
What tests can detect serum antibodies to H. pylori?
- ELISA
- Indirect immunofluorescent assay (IFA)
What biochemical tests can differentiate Campylobacter and Helicobacter species?
Catalase, Nitrate, Urease, Hippurate, Hydrolysis, Growth at 42ºC, Nalidixic Acid, Cephalothin
Which Campylobacter species is sensitive to nalidixic acid?
C. jejuni and C. coli
Which Helicobacter species is resistant to cephalothin?
H. pylori
