BACTERIOLOGY – LECTURE
FINALS | 1ST SEMESTER | TOPIC #4 – Vibrio, Campylobacter, Helicobacter, Aeromonas & Plesiomonas
Lecturer: Prof. Jason T. Chua, RMT, MSMT, Prof. Thynee Tago, RMT
Vibrios
Vibrio furnissii
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Natural habitants of seawater (Halophilic)
○ Excep: Vibrio cholerae and Vibrio
mimicus
Mode of Transmission: Drinking contaminated
water or seafood
Isolated from Gastrointestinal tract (for patients
with Gastritis), blood and wound infections
Motile (single polar flagellum), Gram-Negative
bacteria; comma-shaped; or curved rods
○ In prolonged culture, they may lose the
bended shape, and retain a straight
morphology
Facultative anaerobes or aerobic
Oxidase (+), EXCEPT: Vibrio metschnikoii (oxidase
negative)
Fermentative à Carbohydrate metabolism
Vibrios Culture Media
Alkaline Peptone Water (enrichment media)
○ Incubate 5-8 hours at 35 degrees Celsius
➜ Subculture to TCBS
○ Initial pH of 8.4, for initial isolation
Thiosulfate-citate-bile salts-sucrose (TCBS) agar
○ Sucrose, oxgall (derivative of bile salt)
sodium cholate, bromothymol blue, thymol
blue
■ Important in inhibiting gram
positive bacteria and lactose
fermenting gram negative
bacteria
pH (8.6) – High pH enhances growth of Vibrios,
they cannot grow in an acidic environment / killed
by acids
Smooth Yellow color for Sucrose fermenters
Sucrose Positive
Sucrose Negative
Vibrio cholerae
Vibrio parahaemolyticus
Vibrio alginolyticus
Vibrio vulnificus
Vibrio fluvialis
Vibrio mimicus
MADE BY JOSHUA KINTANAR AND MIGUEL ASTRONOMO
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Vibrio cholerae
Causative agent of CHOLERA
○ GIT infection characterized by severe
diarrhea
○ Death may occur as a result of severe
dehydration
Mode of Transmission: Ingestion of contaminated
seafoods, undercooked shellfish, and drinking
contaminated water
Halotolerant, non-halophilic
Ferments sucrose
ANTIGENIC STRUCTURE AND BIOLOGIC
CLASSIFICATION
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Flagellar (H) antigen
○ Poorly immunogenic
Somatic (O) Antigen – serologically specific
○ O1 strain (causes epidemic and pandemic)
○ Non-O1 straint (cholera-like disease)
○ 130-139 serologic groups of the O antigen
>> there may be different O antigens, but
they share the same H antigen
Vibrio cholerae serotype O1 (3 serogroups)
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Ogawa – isolated in India
Inaba – from the Philippines
Hikojima – from Japan
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Epidemic strain → categorized into 2 biotypes:
Classical & El Tor
○ El Tor is responsible for the recent
pandemics
Classic
El Tor
RBC Hemolysis
Nonhemolytic
Beta-hemolytic
VoguesProskauer
Negative
Positive
Polymyxin B (50
U)
Susceptible
Resistant
Agglutination of
chicken RBC
Negative
Positive
Clinical
Significance
Cholera (First 6
Pandemics = 1817,
1829, 1846, 1863,
1881, 1899)
Cholera Seventh
Pandemic 1961
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Vibrio
O139
Vibrio cholerae O139 (last) is very similar to Vibrio
cholerae O1 El Tor biotype
○ To differentiate: perform Antigen
detection or detect the polysaccharide
capsule
cholerae
Vibr cholerae O1
O1 Ag
Polysaccharide
Capsule
Negative
Positive
Positive
Negative
Vibrio cholerae Pathology and Pathogenesis
Pathogenic only for humans
Normal gastric acidity
○ ID = >1010 or more Vibrio cholerae in
water for infection to occur
○ = <102 - 104 organism in food for infection
to occur
Under normal gastric acidity
If px is taking acid suppressors, then a small amount
would lead to infections of Vibrio cholerae
Vibrio cholerae PATHOGENESIS
● Severe diarrhea = choleragen (potent enterotoxin)
→ bowel mucosa → outpouring of water and
electrolytes (rice-watery stool) → severe
dehydration → severe muscle cramping and anuria
→ death
● Vibrio cholerae produces heat labile enterotoxin
(A & B subunits)
● A subunit causes I level of cAMP (increased cAMP
levels usually leads to hypersecretion of water and
electrolytes into the lumen)
● Diarrhea = dehydration, shock, acidosis, and death
○ Around 20-30 L of water a day
○ Fluid and electrolyte replacement should
be quick
Vibrio cholerae DIAGNOSIS
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Specimen Transport is done with CaryBlair
● SMEAR: Gram-negative bacteria; Comma-shaped
● CULTURE
○ Peptone agar; (rapid growth)
○ Blood Agar Plate with pH 9
○ TCBS; smooth, yellow coloines
● STRING TEST (0.5% sodium deoxycholate)
○ → viscous string
● SEROTYPING
○ Serogroups O1 and O39 → cholera
epidemics
● Biochemical reaction patterns
Vibrio cholerae TREATMENT
● Water and electrolyte replacement is very
important
● Oral tetracycline
○ Note: Some Vibrio cholerae acquired
resistance already (Transmissible
plasmids >> jumping genes)
○ Perform Antimicrobial susceptibility
testing
DIFFERENTIATION OF CLINICALLY SIGNIFICANT Vibrio
Organism
Halop
hilic
Sucros
e Ferm
ADH
Cello
biose
Vibrio
cholerae
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+
Vibrio
parahaemolyt
icus
+
Vibrio
vulnificus
VP
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+
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+
Vibrio
mimicus
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-
Vibrio
anginolyticus
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+
-
Vibrio fluvialis
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+
-
Vibrio furnissi
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+
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+
Clinical Significance of diff. Vibrio spp.
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SPECIMEN: stool, rectal swab (accepted usually in
the acute phase)
MADE BY JOSHUA KINTANAR, MIGUEL ASTRONOMO, DANIEL BUDO
Vibrio cholerae
Epidemic and pandemic cholera
“Asiatic cholera” first noted in India
due to culture and practices
Vibrio
parahaemolyticus
Gastroenteritis
(ingestion
contaminated food)
of
Most common agent of infections
caused by eating contaminated
seafoods
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ABLE TO DEMONSTRATE A
PHENOMENON where clinical
isolates demonstrates hemolytic
capacities on BAP, while those
isolated from non-human sources
are not hemolytic.
Aeromonas hydrophilia
Most common human isolate
● Heat labile enterotoxin and heat stable cytotoxic
enterotoxin
● Produce protease, lipase, and nuclease enzymes
Plesiomonas
➜ Kanagawa phenomenon ➜
Kanagawa toxin, a thermostable
hemolysin seen only in HUMAN
samples ➜ Wagatsuma agar
Wagatsuma agar Is a blood agar
plate that contains high salt,
mannitol concentrations
Vibrio vulnificus
Septicemia and wound infection
Vibrio mimicus
Gastroenteritis and ear infection
(marine environment)
Vibrio
anginolyticus
Wound and ear infection (marine
environment)
Vibrio fluvialis
Gastroenteritis and diarrhea (marine
environment)
Vibrio furnissii
Aeromonas
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Motile, straight, round Gram-negative bacteria
Now categorized as enteric bacteria
Previously belonged to the Vibrionaceae family
together with Aeromonas, but currently they are
categorized as Enteric bacteria
Plesiomonas shigelloides
Important in tropical and subtropical countries, and
in Japan
Infection: gastroenteritis
○ Mild with no blood or mucus in stool
○ Mode of Transmission: Ingestion of
contaminated food
Lab Diagnosis:
○ BAP, NLF on MacConkey & EMB
○ Oxidase and Indole (+)
Found in both fresh and seawater
○ Gastroenteritis, cellulitis, and wound
infection after coming into contact with
contaminated water (either in the drain,
sink, tap water, distilled water etc)
○ Causes diseases in cold-blooded animals
Lab Diagnosis:
○ Mac, Eosin-Methylene Blue, SSA, CIN
medium
○ Perform oxidase test
○ Fermentation of glucose and indole
production
○ Motile: monotrichous
MADE BY JOSHUA KINTANAR, MIGUEL ASTRONOMO, DANIEL BUDO
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Campylobacter
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19 species, but most significant is
Campylobacter jejuni
Campylobacter coli – accounts for 5-10% of
infections in humans
Most frequent isolated species of Campylobacter in humans
Technically they are clinically indistinguishable
● Curved, gram negative bacilli
● Substitute carbolfuchsin when performing gramstaining
● Motile, microaerophilic and capnophilic
● Catalase and oxidase (+)
● Does not oxidize and ferment CHO
● Gram-negative bacilli with comma, S, or “gullwing” shapes
● Disease: Gastroenteritis and diarhea
● Mode of Ingestion: Ingestion of contaminated
materials, direct contact with animal feces, or
infected person
Skirrow’s medium (Vancomycin,
polymyxin B, trimethoprim)
○ Incubated at reduced atmospheric
oxygen (5% O2) with 10% CO2, 85% N
○ Fastidious
Optimal Temperature for growth: 42 to 43
degrees Celsius
○ Prevents growth of Enteric organisms
○ Growth is observed within 48 hours
Gray to pink; yellow to gray colonies, nonhemolytic
and slightly mucoid
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Characteristic darting motility (fast movement);
best demonstrated when using darkfield
microscope
Single, polar flagellum
Guillain-Barré syndrome
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An autoimmune disorder resulting from crossreactivity of Campylobacter antibodies with the
nerve ganglia
Campylobacter Pathogenesis
Virulence factor:
○ Able to produce Cytotoxin, cytotoxic
factor and enterotoxin
○ Organism multiplies in the Small intestine
Helicobacter
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Previously: Campylobacter pylori
Characteristics:
○ Small, curved Gram negative bacilli,
sometimes U form
○ Microaerophilic
■ Requirement: Oxygen (5% O2),
with 10% CO2, 85% N ->
incubated at 35-37 C
■ Can’t grow at 42 C
● Motile by virtue of a tuft of flagella at the end
(lopotrichous)
UREASE
STRONG PRODUCER
OXIDASE
CATALASE
NITRATE
POSITIVE
POSITIVE
NEGATIVE
➜ invades the epithelium ➜ inflammation
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➜ appearance of blood cells in stool
Sometimes bloodstream is invaded & causes
endocarditis, septic arthritis, and meningitis
Campylobacter Laboratory Diagnosis
Specimen: Stool
Smear: “Gull-wing” shaped rods (gram-negative)
CULTURE
○ Campylobacter blood agar (SELECTIVE
due to the presence of Vancomycin,
Polymyxin B, cephaothin, Trimethoprim
and Amphotericin B)
MADE BY JOSHUA KINTANAR, MIGUEL ASTRONOMO, DANIEL BUDO
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Helicobacter pylori PATHOGENESIS
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H. pylori is known to be the agent of
o ANTRAL GASTRITIS,
o DUODENAL ULCERS,
o PEPTIC ULCERS,
o GASTRIC ULCERS,
o Implicated in GASTRIC CARCINOMA
Grows best at pH 6- 7 (cannot survive acidic pH of
the gastric lumen, so it burrows itself into the folds
of the stomach wall)
o Invades mucosa, and releases the toxins
and lipopolysaccharides; damages the
mucosal cells
o Produces protease and ureases and
causes damage to the mucus secreting
cells
o When these cells are damaged, they can no
longer produce mucus—it is very important
covering of the epithelium to protect it from
the effects of acids found inside the lumen
o If there are damaged mucus secreting cells,
amount of mucus covering the lining might
LESSEN and may cause ACIDS TO
DAMAGE
THE
MUCOUS
CELLS
FURTHER producing LESIONS OR
ULCERS
o Presence or large amounts of urease will
produce large amounts of ammonia;
detrimental to the naturally acidic
environment;
will
neutralize
the
hydrochloric acid which is bad for the
function of the stomach
MADE BY JOSHUA KINTANAR, MIGUEL ASTRONOMO, DANIEL BUDO
Helicobacter pylori CLINICAL SYNDROME
Chronic gastritis
Duodenal ulcer
Helicobacter pylori LABORATORY DIAGNOSIS
MICROSCOPY
● Special silver stain or Modified Giemsa
● GOLD STANDARD: Histological staining and
culture of biopsy from stomach or duodenum
Tissue (mashed) ➜ plated on SBAP = incubate at
37 C in microaerophilic and increased humidity
environment
● Colonies: Small, gray, translucent, slightly beta
hemolytic
BIOCHEM: strong and very rapid urea production—
STRONGLY POSITVE
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DIAGNOSIS
Serum = determination of serum IgG antibodies
Stool antigen tests = ELISA
Carbon urea breath test = detects urease (to
confirm Helicobacter colonization and to monitor
treatment for H. pylori)
Endoscopy ➜ to provide sample for testing for
○ Biopsy
○ Microbial culture
Helicobacter pylori CHEMOTHERAPY
Triple therapy
○ Metronidazole + bismuth subsalicylate
or bismuth subctrate + amoxycillin or
tetracycline
○ 14 days
Acid suppressing agent given 4-6 weeks
Proton pump inhibitor
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MADE BY JOSHUA KINTANAR, MIGUEL ASTRONOMO, DANIEL BUDO
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