Vibrio cholerae
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Transcript of Vibrio cholerae
SEVERE VOMITING AND WATERY DIARRHEA
Case Files: Microbiology
Camille ReneeSaint James School of Medicine
CCBS3 2061 STVSource: espemed.com.mx
CASE 23
A 35-year-old woman presents to the emergency room
with a 2-day history of severe diarrhea (approx. 1
L/hr) and vomiting after eating shrimp that seemed
undercooked. Her symptoms started abruptly, with
watery diarrhea followed by vomiting. Her skin is
dry and tents when lightly pinched. A complete
blood count shows an elevated white blood cell
count and an elevated hematocrit. A metabolic panel
shows hypokalemia and low serum bicarbonate.
You assess this patient to be in hypovolemic shock
and metabolic acidosis, and institute appropriate
therapy. Source: Case Files:
Microbiology
CHIEF COMPLAINT
Symptoms
Severe Watery Diarrhea
Profuse Vomiting
Signs
Skin ‘tenting’
Metabolic Acidosis
Hypokalemia
Increased WBC count
Hypovolemic ShockSource: paramedicine.comSource: Case Files: Microbiology
SKIN TENTING INDICATES DEHYDRATION
Skin tenting occurs because of a loss of
elasticity
VOMITING & DIARRHEA DDX
1) E. coli infection
2) Viral
Gastroenteritis i.e.
Rotavirus, Norovirus
3) Aeromonas
4) Vibrio
parahaemolyticus
5) Vibrio choleraeSource: margotbworldnews.com Source:
emedicine.com
1ST DDX: ESCHERICHIA COLI
Source: cdn.phys.org
Gram Negative
bacilli
Causes:
Shiga-like dysentery
Traveler’s diarrhea
Hemolytic uremic
syndrome
Responsible for up
to 45% of
internationalSource: skinsight.comSource: emedicine.com
2ND DDX: VIRAL GASTROENTERITIS
Source: tabletsmanual.com
Sporadic - Mostly
caused by rotavirus in
infants
Acute
gastroenteritis of
adults – mostly
caused by
norovirus
Fecal-oral
transmissionSource: emedicine.com
3RD DDX: VIBRIO SPECIES
Gram Negative
comma-shaped bacilli
Single Polar Flagellum
Serotypes O1 (El Tor)
and O139 (Bengal)
Consumption of
contaminated seafood i.e. shellfish, plankton
Grows in Alkaline
MediaSource: http://upload.wikimedia.org/Source: Case Files:
Microbiology
4TH DDX: AEROMONAS
Gram negative rod
Cholera-like or
dysenteric
gastroenteritis
Consumption of
contaminated
seafood
Skin infections are
common Source: medical-labs.netSource: Santhosh, SJSM Source: oscarfish.com
DDX: PROCESS OF ELIMINATION
LABORATORY INVESTIGATION
Source: judyancheta.files.wordpress.com
SELECTING THE CAUSATIVE ORGANISM
Vibrio cholerae
vs.
Vibrio
parahaemolyticus
or Vibrio
vulnificus
Vibrio
vs.
Aeromonas
DDX: TABLE OF CHARACTERISTICS
VIBRIO SPECIES CAN BE O129 RESISTANT!
O129 (2,4-diamino-6,7-diisopropylpteridine)
differential disc is Vibriostatic
Authors: Hofer E1, Reis EM, Quintaes BR,
Rodrigues DP, Feitosa IS, Angelo MR,
Ribeiro LH.
O1 (El Tor) and O22 serogroups were isolated from patients with enteritis in Ceará, Brazil during 1991-1993
2/7,058 V. cholerae Samples Were Resistant To O129
Additionally, these O129-resistant strains of V. cholerae O1 and O22 Were ALSO Resistant To Trimethoprim/ Sulfamethoxazole
DX: VIBRIO CHOLERAE
Gram Negative curved bacilli
with Single Polar Flagellum
IP: 1-3 days
Fecal-oral transmission
Serotypes O1 (El Tor) and
O139 (Bengal) are
Responsible for Epidemic
Disease
Consumption of
contaminated seafood
Grows in Alkaline MediaSource: cholera1.wikispaces.comSource: Case Files:
Microbiology
MOST COMMON MODES OF TRANSMISSION
Contaminated
Water
Ingestion of Raw
Shellfish
Flooding in
Underdeveloped
Countries
Poor Hygiene
Source: zipheal.com Source: blogcdn.comSource: Case Files-
Microbiology
THE MECHANISM OF CHOLERA TOXIN (CTX)
Bacteria attach to upper intestine
via pili and subsequently colonize
Cholera enterotoxin
1 A subunit
5 B subunits
B subunits bind to a GM1 ganglioside receptor
on the mucosal cell to allow entry of the A subunit
A subunit Overactivates Adenylate Cyclase (Gs
protein)
Hypersecretion of Water, Chloride and other
Electrolytes into the intestinal lumenSource: Microsoft OfficeSource: Case Files:
Microbiology
Source: emedicine.com
Source: Lippincott’s
DIAGNOSTIC TESTS
Clinical diagnosis
Stool sample
Cary Blair media
TCBS agar (yellow
colonies)
Hanging drop test
Darting motility
Alkaline peptone
water (enrichment
media)
Crystal VC® dipstick
rapid test
Source: amsrapidtest.comSource: www.cdc.govSource: microrao.com
DIAGNOSTIC TESTS
Specific anti-
serum can be
used in
immobilization
tests i.e.
cessation of
motility of the
organism
Electron
microscopy
Source: thumbs.dreamstime.comSource: emedicine.com
SUPPORTIVE MANAGEMENT OF CHOLERA
Oral or Intravenous
Rehydration (1st line
therapy)
Ringer’s Lactate
Solution (50-100
mL/kg/hr)
Oral Rehydration Salts
(ORS)
It should take
approximately 4 hours
to Return the Patient to
Normal Hydration StatusSource: c1.staticflickr.com Source: tspwiki.com Source: emedicine.com
Isotonic,
bicarbona
te-
containin
g fluids
are key!
SECOND LINE THERAPY
Oral Antibiotics (2nd
Line Therapy)
Doxycycline(preferred)
Tetracycline
Azithromycin
Erythromycin Trimethoprim/Sulfamethoxaz
ole
Ciprofloxacin
Ampicillin
Norfloxacin
Source: bipolarbrain.comSource: emedicine.com
VIBRIO SPECIES CAN BE O129 RESISTANT!
O129 (2,4-diamino-6,7-diisopropylpteridine) differential disc is Vibriostatic
Authours Hofer E1, Reis EM, Quintaes BR, Rodrigues DP, Feitosa IS, Angelo MR, Ribeiro LH.
O1 (El Tor) and O22 serogroups were isolated from patients with enteritis in Ceará, Brazil during 1991-1993
2/7,058 V. cholerae Samples Were Resistant To O129
Additionally, these O129-resistant strains of V. cholerae O1 and O22 Were ALSO Resistant To Trimethoprim/ Sulfamethoxazole
REHYDRATION IS LIFE SAVING
Rehydration Usually
Results in Patient Recovery
If Left Untreated, complications include:
Hypoglycemia: patient becomes too ill to eat
Hypokalemia: abundant loss of electrolytes
Acute Tubular Necrosis or Renal Failure:
kidney malfunction associated with
hypovolemic shock
Death from dehydration Source: . globalparent.unicef.ieSource: Mayoclinic.org
OVERALL TREATMENT PLAN
5 Steps
WHEN TO SUSPECT CHOLERA
According to the World Health
Organization, a case of cholera is
suspected when:
Area with disease Not known to be
present
A patient aged 5 years or older develops
Severe Dehydration or dies from Acute
Watery Diarrhea
Area With Noted Cholera epidemic
A patient aged 5 years or older develops
Acute Watery Diarrhea, With or Without
Source: b.3cdn.netSource: who.int
MORTALITY
Access to Intravenous
Therapy Determines
Cholera’s Rate of Mortality
Before IV therapy, death caused
by cholera was Greater Than
50%; it is now <1% with
appropriate therapy
Mortality rate is still the Highest
in Africa due to the lack of
equipment in some countries Source: . www.medindia.netSource: emedicine.com Source: Toronto Notes
REDUCE THE INCIDENCE OF CHOLERA
Prevent cholera
transmission by:
Engaging in
appropriate
hygienic
practices
Drinking
chlorinated or
boiled water
Ensuring
thorough cooking
Source: www.getreadyforflu.org Source: filteredwatertap.com Source: Case Files:
Microbiology
GASTRIC ACIDITY FIGHTS CHOLERA
Cholera bacilli usually
Cannot Survive in Acidic
Environments
Patients with Achlorhydria
(Low Levels of Stomach
Acid) from taking
antacids, H2 blockers, or
proton pump inhibitors
are at a Greater Risk of
Developing CholeraSource: . cdn.return2health.net Source: Mayoclinic.org
PASSIVE IMMUNITY
Infants Who
Derive Passive
Immunity from
nursing mothers
who have
previously had
cholera are Not
Susceptible to
CholeraSource: . foodnavigator-asia.comSource: Mayoclinic.org
VACCINES FOR TRAVELERS
Vaccines are available in Select Countries
1. Parenteral
Approximately 50% efficacy
2. Killed whole cell V. cholerae with
recombinant B-subunit of CTX (Dukoral)
Approximately 50% efficacy after 3 years
3. Live attenuated CVD 103-HgR
>90% efficacy after 1 week
Source: . static.ddmcdn.comSource: slideshare.net Source: Toronto Notes
MULTIPLE CHOICE QUESTIONS
QUESTION 1
Which of the following statements is true of cholera enterotoxin?
a) Produces its effect by stimulating adenylate cyclase
activity in mucosal cells
b) Causes destruction of the
intestinal mucosa allowing for
invasive infection
c) Causes a net efflux of ions and
water from tissue into the lumen
of the large intestine
d) Is a protein with a molecular weight of
approximately 284,000 daltonsSource: sharinginhealth.caSource: Case Files:
Microbiology
ANSWER
A. Vibrio cholerae consists of an
enterotoxin A subunit that increases
adenylate cyclase activity, causing
hypersecretion of chloride and bicarbonate.
This prevents sodium and chloride to be
absorbed into cells, resulting in a massive
secretion of fluid into the intestinal lumen.
Source: Case Files:
Microbiology
QUESTION 2
What differential medium is used to distinguish Aeromonas spp. from Vibriospp.?
a) Xylose lysine desoxyscholate (XLD) agar
b) O129 differential disc
c) Hektoen enteric agar
d) Buffered charcoal yeast extract agar
e) Mannitol salt agar
ANSWER
B. To distinguish between Vibrio and
aeromonas, an O129 differential disc (2,4-
diamino-6,7-di-isopropylpteridine phosphate)
susceptibility is done:
Vibrio = “S” (susceptible)
Aeromonas =“R” (resistant)
Source: Santhosh, SJSM
QUESTION 3
What is the first-line treatment for cholera?
a) Administering the antimicrobial agent
doxycycline
b) Provide vaccination to stimulate the
patient’s immune system
c) Volume replacement with isotonic
bicarbonate fluid (i.e. Ringer’s lactate
solution)
d) Administering the antimicrobial agent
quinolone
ANSWER
C. The treatment of cholera involves
volume replacement with isotonic,
bicarbonate-containing fluids, either using
oral rehydration solutions in mild to
moderate dehydration or IV fluids, such as
Ringers lactate solution, in the profoundly
dehydrated or those unable to tolerate oral
intake.
Source: Case Files:
Microbiology
QUESTION 4
Which of the following culture plates may
be used to isolate Vibrio species, based
on its requirement of salt for growth?
a) Thayer-Martin medium
b) MacConkey agar
c) Blood agar
d) TCBS agar
Source: . c1.staticflickr.com
ANSWER
D. Thiosulfate-citrate-bile salts-sucrose
(TCBS) agar is the culture medium used
to selectively isolate Vibrio species. Blood
agar detects hemolysis, Thayer-Martin
medium isolates Neisseriae, and MacConkey
agar detects lactose-fermenting organisms.
Source: Santhosh, SJSM
QUESTION 5
An individual experiences watery diarrhea and fever
after eating raw shellfish in San Francisco. When
cultured onto a selective medium called TCBS, it
yielded green colored colonies.
Which among the following is the organism that is
responsible for the above manifestations and
symptoms?
a) Salmonella typhi
b) Vibrio parahaemolyticus
c) Vibrio cholerae
d) Clostridium difficile
e) Campylobacter jejuni Source: vibrio-cholerae.org/Source: Santhosh, SJSM
ANSWER
B. Like V. cholerae, V.
parahaemolyticus causes acute
gastroenteritis following ingestion of
contaminated seafood such as raw fish or
shellfish. The patient will develop vomiting,
abdominal cramps, fever, and diarrhea. It is
diagnosable on TCBS agar as green
colonies.
Source: Case Files:
Microbiology
GOOD JOB!
Source: . slvrdlphn.com
ACKNOWLEDGEMENTS
Professors
Dr. Mohamed Shata
Dr. Rana Zeine
Dr. Anwural Siddiqui
Dr. Fatima Marankan
Dr. Daphne Santhosh
REFERENCES
1. Liberman, M.A. & Ricer, E. (2010). Lippincott’s illustrated Q&A review of biochemistry. Wolters
Kluwer: Hong Kong
2. Kumar, V., Abbas, A.K., & Fausto, N. (2005). Robbins and cotran pathologic basis of disease,
7th ed. Elsevier Saunders: Philadelphia
3. Toy, E.C., Uthman, M.O., Uthman, E., & Brown, E.J. (2008). Case files: microbiology. United
States of America: McGraw-Hill Companies, Inc.
4. Cholera diagnosis. (2014). Retrieved March 3, 2015 from
http://www.cdc.gov/cholera/diagnosis.html
5. Cholera. (2014). Retrieved March 6, 2015 from http://www.mayoclinic.org/diseases-
conditions/cholera/basics/definition/con-20031469
6. Le, T., Bhushan, V., & Sochat, M. (2014). First aid for the usmle step 1. McGraw-Hill: Chicago
7. Cholera. (2015). Retrieved March 9, 2015 from
http://emedicine.medscape.com/article/962643-overview
Questions?
Source: . pixshark.com