Embed Size (px)
DESCRIPTION
Campylobacter jejuni & Helicobacter pylori
Citation preview
Dr.T.V.Rao MD
Dr.T.V.Rao MD 1
Dr.T.V.Rao MD 2
Campylobacters causes Important Zoonotic Infections
Dr.T.V.Rao MD 3
First isolated as Vibrio fetus in 1909 from
spontaneous abortions in livestock
Campylobacter enteritis was not
recognized until the mid-1970s when
selective isolation media were developed
for culturing campylobacters from human
feces
Most common form of acute infectious
diarrhea in developed countries; Higher
incidence than Salmonella & Shigella
combined
History of Campylobacter
Dr.T.V.Rao MD 4
Gram-negative
Helical (spiral or curved) morphology; Tend to be
pleomorphic
Characteristics that facilitate penetration and
colonization of mucosal environments (e.g.,
motile by polar flagella; corkscrew shape)
Microaerophilic atmospheric requirements
Become coccoid when exposed to oxygen or
upon prolonged culture
Neither ferment nor oxidize carbohydrates
General Characteristics
Common to Superfamily
Dr.T.V.Rao MD 5
Bacteria commonly found in animal feces. It is one of the most common causes of human gastroenteritis in the world. Food poisoning caused by Campylobacter species can be severely debilitating, but is rarely life-threatening. It has been linked with subsequent development of Guillain-Barre syndrome (GBS), which usually develops two to three weeks after the initial illness
Campylobacter jejuni
Dr.T.V.Rao MD 6
Small, thin (0.2 - 0.5 um X 0.5 - 5.0 um),
helical (spiral or curved) cells with typical
gram-negative cell wall; “Gull-winged”
appearance
• Tendency to form coccoid & elongated
forms on prolonged culture or when
exposed to O2
Morphology & Physiology of Campylobacter
Dr.T.V.Rao MD 7
Motility – A Darting type
Distinctive rapid darting motility
• Long sheathed polar flagellum at one (polar) or both (bipolar) ends of the cell
• Motility slows quickly in wet mount preparation
Dr.T.V.Rao MD 8
Growth Requirements
Microaerophilic & capnophilic 5%O2,10%CO2,85%N2
Thermophilic (42-43C) (except C. fetus)
• Body temperature of natural avian reservoir
May become nonculturable in nature
Dr.T.V.Rao MD 9
Important Zoonotic Infection
Campylobacter remains the leading cause worldwide of zoonotic disease in humans, surpassing Salmonella infections. Moreover, cases are still believed to be underreported. Often causing the same symptoms as Salmonella, such as mild to severe diarrhea, Campylobacter infections can also be an infectious trigger for the more serious Guillain-Barre Syndrome.
Dr.T.V.Rao MD 10
C.jejuni carried in …. Although C. jejuni is
not carried by healthy individuals in the United States or Europe, it is often isolated from healthy cattle, chickens, birds and even flies. It is sometimes present in non-chlorinated water sources such as streams and ponds.
Dr.T.V.Rao MD 11
Feces refrigerated & examined within few hours
Rectal swabs in semisolid transport medium
Blood drawn for C. fetus
Care to avoid oxygen exposure
Selective isolation by filtration of stool specimen
Enrichment broth & selective media
Filtration: pass through 0.45 μm filters
Laboratory Diagnosis
Dr.T.V.Rao MD 12
Microscopy:
Gull-wing appearance in gram stain
Darting motility in fresh stool (rarely done in
clinical lab)
Fecal leukocytes are commonly present
Identification:
Growth at 25o, 37o, or 42-43oC
Hippurate hydrolysis (C. jejuni is positive)
Susceptibility to nalidixic acid & cephalothin
Laboratory Identification
Dr.T.V.Rao MD 13
An atmosphere with reduced O2 (5% O2)
with added CO2 (10% CO2)
At 42 ℃ (for selection)
Several selective media can be used (eg, Skirrow’s medium)
Two types of colonies:
watery and spreading
round and convex
Culture
Dr.T.V.Rao MD 14
Selective Medium
• Blood-free, charcoal-based selective medium agar (CSM) for isolation of Campylobacter jejuni
Dr.T.V.Rao MD 15
Characteristic Result
Growth at 25 °C -
Growth at 35-37 °C -
Growth at 42 °C +
Nitrate reduction +
Catalase test +
Oxidase test +
Growth on MacConkey agar +
Motility (wet mount) +
Glucose utilization -
Hippurate hydrolysis +
Resistance to nalidixic acid -
Resistance to cephalothin +
Characteristics of C.jejuni
[
e
d
it
]
S
e
e
a
l
s
o •C
a
m
py
lo
ba
ct
eri
os
is
Dr.T.V.Rao MD 16
Infectious dose and host immunity determine
whether gastro enteric disease develops • Some people infected with as few as 500 organisms
while others need >106 CFU
Pathogenesis not fully characterized • No good animal model
• Damage (ulcerated, edematous and bloody) to the
mucosal surfaces of the jejunum, ileum, colon
• Inflammatory process consistent with invasion of the
organisms into the intestinal tissue; M-cell (Payer's
patches) uptake and presentation of antigen to
underlying lymphatic system
Non-motile & adhesion-lacking strains are a
virulent
Pathogenesis & Immunity
Dr.T.V.Rao MD 17
Cellular components: Endotoxin
Flagellum: Motility
Adhesins: Mediate attachment to mucosa
Invasins
GBS is associated with C. jejuni Serogroup O19
S-layer protein “microcapsule” in C. fetus:
Extracellular components: Enterotoxins
Cytopathic toxins
Putative Virulence Factors
Dr.T.V.Rao MD 18
Other Species of Campylobacters
C jejuni infections may also produce serious bacteremic conditions in individuals with AIDS. Most reported bacteremia's have been due to Campylobacter fetus fetus infection. Campylobacter lari, which is found in healthy seagulls, has also been reported to produce mild recurrent diarrhea in children
Dr.T.V.Rao MD 19
Other Species of Campylobacters
Campylobacter
upsaliensis may cause diarrhea or bacteremia, while Campylobacter hyointestinalis, which has biochemical characteristics similar to those of C fetus, causes occasional bacteremia in immunocompromised individuals. Dr.T.V.Rao MD 20
Gastroenteritis:
•Self-limiting; Replace fluids and electrolytes •Antibiotic treatment can shorten the excretion period;
Erythromycin is drug of choice for severe or complicated
enteritis & bacteremia; Fluoroquinolones are highly active
(e.g., ciprofloxacin was becoming drug of choice) but
fluoroquinolones resistance has developed rapidly since
the mid-1980s apparently related to unrestricted use and
the use of enrofloxacin in poultry
•Azithromycin was effective in recent human clinical trials
•Control should be directed at domestic animal reservoirs
and interrupting transmission to humans
Treatment, Prevention & Control
Dr.T.V.Rao MD 21
Complications are relatively rare, but infections have
been associated with reactive arthritis, hemolytic uremic syndrome, and following septicemia, infections of nearly any organ. The estimated case/fatality ratio for all C. jejuni infections is 0.1, meaning one death per 1,000 cases. Fatalities are rare in healthy individuals and usually occur in cancer patients or in the otherwise debilitated. Only 20 reported cases of septic abortion induced by C. jejuni have been recorded in the literature.
Complication are rare but occurs occasionally
Dr.T.V.Rao MD 22
Guillain-Barre syndrome (GBS), a demy elating disorder
resulting in acute neuromuscular paralysis, is a serious sequelae of Campylobacter infection . An estimated one case of GBS occurs for every 1,000 cases of Campylobacteriosis Up to 40% of patients with the syndrome have evidence of recent Campylobacter infection . Approximately 20% of patients with GBS are left with some disability, and approximately 5% die despite advances in respiratory care. Campylobacteriosis is also associated with Reiter syndrome, a reactive arthropathy. In approximately 1% of patients with campylobacteriosis, the sterile postinfection process occurs 7 to 10 days after onset of diarrhea . Multiple joints can be affected, particularly the knee joint. Pain and incapacitation can last for months or become chronic.
Sequelae to Infection
Dr.T.V.Rao MD 23
Complications with C.jejuni
Guillain-Barre
Syndrome (GBS)
• Favorable
prognosis with
optimal
supportive care
Intensive-care unit
for 33% of cases
Dr.T.V.Rao MD 24
Dr.T.V.Rao MD 25
A Tribute to Warren and Marshall
for Discovery of H.pylori
Dr.T.V.Rao MD 26
Helicobacter pylori (H. pylori) is a type of bacteria.
Researchers believe that H. pylori is responsible for the majority of peptic ulcers. H. pylori infection is common in the United States.
About 20 per cent of people under 40 years old and half of those over 60 years have it. Most infected people, however, do not develop ulcers. Why H. pylori does not cause ulcers in every infected person is not known. Most likely, infection depends on characteristics of the infected person, the type of H. pylori, and other factors yet to be discovered
Helicobacter pylori
Dr.T.V.Rao MD 27
Helicobacter pylori is the prototype organism in this
group. It is associated with antral gastritis, gastric ulcers, and gastric carcinoma.
Helicobacter pylori
Dr.T.V.Rao MD 28
Helicobacter pylori
Helicobacter pylori is a spiral gram negative bacteria.
It has a multiple polar flagella above the pole and motile
Dr.T.V.Rao MD 29
Peptic ulcers have plagued men throughout the
centuries, but the exact cause of the condition was uncertain. In 1940, Dr. A. Stone Freedberg of Harvard Medical School identified unusual curved bacteria in the stomachs of ulcer victims; he suspected that they might be responsible for ulcers but abandoned the research when his team was unable to grow the bacteria in the laboratory
Beginning of Scientific understanding
Dr.T.V.Rao MD 30
Helicobacter pylori (H.pylori for short) was first
discovered in the stomachs of patients with gastritis & stomach ulcers nearly 25 years ago by Dr Barry J. Marshall and Dr J. Robin Warren of Perth, Western Australia. At the time (1982/83) the conventional thinking was that no bacterium can live in the human stomach as the stomach produced extensive amounts of acid which was similar in strength to the acid found in a car-battery. Marshall & Warren literally “re-wrote” the text-books with reference to what causes gastritis & gastric ulcers.
History of H.pylori
Dr.T.V.Rao MD 31
Global prevalence of H. Pylori
Land Mark Changes in H.pylori
The name of the bacterium was grammatically corrected in 1987 to Campylobacter pylori and, in 1989 the
bacterium was renamed
Helicobacter pylori and
assigned as the type species of a novel genus due to its 16s rRNA sequence.
Dr.T.V.Rao MD 33
How is it transmitted?
Believed to be transmitted orally due to tainted food or water.
Also believed to be passed through belching, or gastro-esophageal reflux, which is when small amount of stomachs contents is forced up the esophagus.
After this process, it’s believed that the H. Pylori is passed orally.
Genes Contribute to Pathogenicity
CAG – Cytotoxin associated gene
Vac – Vacuolating cytotoxin gene
Dr.T.V.Rao MD 35
It is well established that urease, Vacuolating cytotoxic VacA, and the pathogenicity island (cag PAI) gene products, are the main factors of virulence of this organism. Thus, individuals infected with strains that express these virulence factors probably develop a severe local inflammation that may induce the development of peptic ulcer and gastric cancer. The way the infection spreads throughout the world suggests the possibility that there are multiple pathways of transmission.
Pathogenic Mechanism
Dr.T.V.Rao MD 36
Culturing H.pylori H.pylori grows on Skirrow”s medium
with 1Vancomycin, 2 Polymyxin 3 Trimethoprim Grows in 3 -6 days at
370c Colonies appear Translucent 1-2 mm in
diameter Optimal growth occurs
in Microaerophic environment
Dr.T.V.Rao MD 37
Biochemical Characters
Motile
Catalase +
Oxidase +
Strong producer of
Urease
Dr.T.V.Rao MD 38
Urease
C=O(NH2)2 + H+ + 2H2O HCO3- + 2 (NH4
+) Urea Bicarbonate Ammonium
ions
And then…
HCO3- CO2 + OH-
Urea Hydrolysis
Dr.T.V.Rao MD 39
H.pylori is found in the deep mucus layer
Grows optimally at pH 6.0 to 7.0
But gastric mucosa has a strong buffering in spite of lower pH on the lumen side of stomach
H.pylori also produces a protease that modifies the gastric mucus and further reduces the ability of acid through the mucus
Pathology and Pathogenesis
Dr.T.V.Rao MD 40
Mechanisms in Pathogenicity
Dr.T.V.Rao MD 41
Localization of H.pylori
Dr.T.V.Rao MD 42
The potential character of H.pylori lie with
production of potent Urease activity which yields production of Ammonia and further buffering acid.
H.pylori is quite motile even in mucus finds its way to epithelial surface
H.pylori overlies the gastric type but not intestinal epithelial cells.
Pathogenesis
Dr.T.V.Rao MD 43
Factors contributing to Peptic ulceration
There is a strong association between presence of H.pylori infection and peptic ulceration
Mucosal inflammation and damage involves both bacterial and host factors
Dr.T.V.Rao MD 44
H.pylori causes Peptic ulcers in the Stomach
Dr.T.V.Rao MD 45
Lipopolysaccharides - damage mucosal cells
and Ammonia produced by Urease activity may directly damage cells.
Gastritis – Chronic and active inflammation establishes Polymorph nuclear and Mononuclear cell infiltration within the Epithelial and Lamina propria
Events lead to Destruction of epithelium is common.
Glandular atrophy is common.
Factors influencing Pathogenicity
Dr.T.V.Rao MD 46
Acute infection
Upper Gastrointestinal illness
Nausea
Pain
Fever – very occasionally
Acute symptoms lasts for < 1 week,
May extend up to 2 weeks
Infection last for years, decades or even lifetime
Clinical Manifestations
Dr.T.V.Rao MD 47
Consequences of H.pylori Infection
Dr.T.V.Rao MD 48
About 90 % of patients with Duodenal ulcer, and 50- 80 % of gastric ulcers are associated with H.pylori infection.
H.pylori may have greater role in Gastric carcinoma and Lymphomas
Association of Duodenal and Gastric ulcers in H.pylori
Dr.T.V.Rao MD 49
Mechanism of Cancer in H.pylori
Dr.T.V.Rao MD 50
Specimens for histopathology – Gastric biopsy specimens can be used for Histological examination
Specimens obtained after Gastroscopy, Biopsy, routine stains will demonstrate Gastritis and special stains show curved spiral organisms
Specimens collected in sterile saline mixed are used for culturing
Laboratory Diagnosis
Dr.T.V.Rao MD 51
Endoscopy – Gastric Biopsy
Dr.T.V.Rao MD 52
Serology The detection of
Antibodies in active infection is useful
But the tests are limited utility as antibodies persist even after H.pylori infection is eradicated.
Several commercial kits are available, but lacks the role in identifying acute infections.
Dr.T.V.Rao MD 53
Special Tests for H.pylori
Rapid tests for detection of Urease activity are widely used in presumptive identification of Gastric Biopsy specimens.
Gastric Biopsy can be placed into urea containing medium with color indicator.
If H.pylori is present the Urease rapidly splits urea and resulting shift in pH yields a color change in the medium
Dr.T.V.Rao MD 54
Urea Breath Test
H. pylori infection can
be detected in the
exhaled breath using
this special test. This
test is positive only if
the person has a
current infection.
Sensitivity and
specificity of this test ranges from 94-98%.
Dr.T.V.Rao MD 55
Carbon-14-urea Breath Test
Dr.T.V.Rao MD 56
Urea Breath Test
In this test 13C or 14C labeled urea is ingested by patients
If H.pylori is present the urease activity generates labeled Co2 that can be detected in the patients exhaled breath
Dr.T.V.Rao MD 57
Antigen Detection Test in Stool
Detection of H.pylori antigen in stool is appropriate test in patients with H.pylori infection
Absence of antigen indicates cure of Infection after Chemotherapy.
Dr.T.V.Rao MD 58
H.pylori and Cancer
. If a person has had an H.pylori infection constantly for 20-30 years, it can lead to cancer of the stomach. This is the reason that the World Health Organization's (WHO) International Agency for Research into Cancer (IARC) has classified H.pylori as a “Class- I-Carcinogen” i.e. in the same category as cigarette smoking is to cancer of the lung & respiratory tract.
59 Dr.T.V.Rao MD
Triple therapy has prompt response, contain a
combination of following drugs
1 Metronidazole
2 Bismuth subsalicylate or Bismuth sub citrate
3 Amoxicillin or Teracycles
administered up to 14 days
Eradicates H.pylori
In 70 – 95 % of patients
Acid suppressing agent is supporting
Treatment
Dr.T.V.Rao MD 60
Other alternatives
Proton pump inhibitor directly inhibit
H.pylori
Combined with
Amoxicillin
Clarithromycin or Amoxicillin
And Metronidazole
Other Drug Combinations
Dr.T.V.Rao MD 61
A vaccination against Helicobacter pylori may
represent both prophylactic and therapeutic approaches to the control of H. pylori infection. Different protective H. pylori-derived antigens, such as urease, vacuolating cytotoxin A, cytotoxin-associated antigen, neutrophil-activating protein and others can be produced at low cost in prokaryote expression systems and most of these antigens have already been administered to humans and shown to be safe.
Vaccines trails for H.pylori are in Progress
Dr.T.V.Rao MD 62
In Developed countries H.pylori are present in <20 %
of the persons below 30 years.
By 60 years prevalence increases to 40 – 60 %
In Developing countries prevalence of infection is higher to 80 % even in younger individuals
Person to person transmission of H.pylori is likely because of interfamilial clustering of infection
Acute epidemics of Gastritis suggest a common source of H.pylori.
Epidemiology
Dr.T.V.Rao MD 63
Helicobacter pylori changes the future of Gastroenterology
Dr.T.V.Rao MD 64
Barry J. Marshall and J. Robin Warren have been awarded the 2005 Nobel Prize in medicine
Dr.T.V.Rao MD 65
Helicobacter Foundation
The "Helicobacter Foundation" was founded by Prof. Barry J. Marshall in early 1994, and is dedicated to providing you with the latest information about Helicobacter pylori, its diagnosis, treatment and clinical perspectives.
Dr.T.V.Rao MD 66
Created by Dr.T.V.Rao MD for ‘e’ learning resources for Microbiologists
in Developing World
Dr.T.V.Rao MD 67
