Download Campylobacter fetus subsp. intestinalis

Diagnostic microbiology
lecture: 7
CAMPYLOBACTER
Abed ElKader Elottol
MSc. Microbiology
2010
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GENERAL CHARACTERISTICS OF CAMPYLOBACTER
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Small, delicate, spirally or curved.
Gram-negative bacteria
Oxidase positive
Fastidious
Microaerophilic
Motile by polar flagella
SPECIES
1. Camplylobacter fetus subsp. fetus Non pathogenic
2. Campylobacter fetus subsp. intestinalis
3. Campylobacter fetus subsp. jejuni
4. Campylobacter pylori or Helicobacter pylori (Peptic ulcer)
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Sources of Campylobacters:
GIT and reproductive organs of:
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Chicken
Sheeps
Cattles
Dogs
Cats
Transmission routes
Direct occupational
Contact
Farmers,Butchers,
Poultry processors
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Direct domestic
Contact
Dogs,Cats
Children to children
Indirect transmission
Untreated water
Raw milk
Undercooked meat
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DISEASES
1. meningitis and meiningoencephalitis in infants:
Mortality rate is 50% despite intensive treatment.
Specimens include blood, CSF and stool Mostly
caused by C. intestinalis.
2. Bacteremia: In children: caused by both C.
intestinalis and jejuni. Specimen is blood.
3. Disseminated infections in adults: Usually in
debilitated patients with one or more of the following
conditions:
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1. Cardiovascular disease.
3. Endocrinological disorders
4. Chronic alcoholism
5. Malignancies
Causative organism: Mostly C. intestinalis
= Specimen: Blood, pericardium, pleura, joints and stool.
• II. Enteric Infections:
• Species of the genus campylobacter, are one of the major
etiologic agents of bacterial enteritis.
• Campylobacter enteritis is accompanied by fever, headache,
muscular pain, nausea and pain.
• 24 hours following this acute phase, diarrhea develops which
may be bloody, mucoid and watery.
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Isolation of Campylobacter from Stool
• 1. Filtration Technique:
1. One gram of stool specimen is suspended in 20 ml saline
2. Agitate vigorously (on Vortex for 10-15 seconds).
3. Centrifuge at 650-800 rpm for 10 minutes.
4. Take four to five milliliters into a syringe
5. Pass the liquid through two 25 μm filter chamber:
=The upper non-sterile chamber is fitted with an 8.0 and 1.2 μm
Millipore membrane filter.
= The lower steam-sterilized chamber contains a 0.65 um membrane.
6. 2-4 drops of the filtrate are spread onto chocolate agar and
incubated.
7. Both C. jejuni and intestinalis grow well on this medium and are very
Characteristics.
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Incubation conditions
1. Microaerophilic environment:
• 5% O2
• 10% CO2
• 85% N2
2. To increase the size of C. jejuni, incubate at 42 oC.
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Selective media
• The introduction of selective media made the isolation of
Campylobacter species from a stool sample possible:
• EXAMPLE: Blood Agar + Antibiotic solution.
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Skirrow agar:
• Campylobacter Skirrow Agar is a selective solid medium used
for the cultivation and isolation of Campylobacter jejuni from
fecal specimens.
• Vancomycin, Polymyxin B, Trimethoprim
• Colonies of C. jejuni will appear on Campylobacter Skirrow
agar as small, mucoid, flat or slightly raised, non-hemolytic
translucent and gray.
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Butzler solution
• Bacitracin
• Cyclohexamide
• Colistine B sulfate
• Cephazolin sodium
• Novobiocin
Campy-BAP it contain
• Vancomycin
• Trimethoprim
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Advantages of filtration technique over the selective media
1. All non-campylobacter organisms are retained by the filters.
2. Both C. intestinalis and jejuni will grow on Chocolate agar
unlike the selective media which allows only one of the two.
3. You do not need to worry about the decay of antibiotics as in
the selective media.
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SEROLOGICAL TESTS:
• Serological tests are not suitable for routine investigation
due to the lack of standardized antigen suspensions and
reference sera.
ANTIBIOTIC SENSITIVITY:
• Erythromycin is the drug of choice.
• Chloramphenicol,
aminoglycosides,
carbenicillin,
clindamycin and tetracycline are also effective.
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HELICOBACTER PYLORI
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Helicobacter pylori
• Previous name : Campylobacter pylori
• First isolated in 1983 from human stomach
• Gram-negative bacilli
• Curved, spiral or seagull-shaped
• Motile with multiple polar flagella
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CULTURAL CHARACTERISTICS
• Grow best at 42-43 oC
• Microaerophile (7% oxygen)
• Strongly urease positive (different from Campylobacter)
• Grow on enriched & selective media Modified Skirrow’s agar
(Blood agar with antibiotics)
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HABITAT
• Human gastric mucosa (world-wide distribution)
• Approx. 50% of adults >60 years are infected
TRANSMISSION (person to person)
• Oral-oral
• Fecal-oral
• There are clusters of infection in families
DISEASES BY H. PYLORI
• Gastritis
• Gastric & peptic ulcer
• Gastric cancer
• Most individuals tolerate the presence of H. pylori for decades
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CLINICAL FEATURES
• Incubation period : few days
• Nausea, flatulence & bad breath
• Recurrent epigastric pain & dyspepsia
• Epigastric burning sensation
• Bleeding from ulcer
• No dissemination
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LAB IDENTIFICATION
Specimen : gastric biopsy
Direct gram-stained smear of crushed biopsy
Direct urease test
Place a piece of biopsy in urea broth- red color change in few min to 2
hrs
• Culture : On Skirrow’s medium
° Oxidase +ve, Urease +ve, catalase +v
• Serodiagnosis
° ELISA to detect IgG (not established to differentiate active vs past
infection)
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H. pylori Stool Antigen (HpSA) test
Urea Breath Test
• Patient ingests radio-labeled 14C urea
If H. pylori infection present :
• Urease produced by the organism, hydrolyses
urea to NH3 and radio-labeled -HCO3
that is exhaled as CO2 which is detected by
spectrometer
• Has good sensitivity & specificity.
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TREATMENT
Triple therapy
• Metronidazole +
• Clarythromycin or amoxycillin +
• Omeprazole
• Vaccine development : under trial
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END OF LECTURE
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