Vibrio, Aeromonas, Campylobacter, Helicobacter

Water Organisms

these 4 genera cause diarrheal diseases and other infections

Vibrio, Aeromonas, Campylobacter, and Helicobacter (Campylobacter-like)

which genera is associated with large epidemics and pandemics?

Vibrio

which genera plays a role in GBS?

Campylobacter

which genera causes ulcers?

Helicobacter

GBS

Guillian-Barre Syndrome

Which genera relates to stool culture?

Aeromonas

Vibrio is the causative agent of what?

cholera (severe diarrhea)

where is Vibrio found?

fresh, brackish, and salt water

what are the 6 reasons there is a significant rise in isolation of Vibrio?

Increased:

1. ocean water temp

2. travel to cholera endemic places

3. raw seafood consumption

4. aquatic/recreational water exposure

5. immunocompromised people

6. awareness of microbes

Vibrio 4 risk factors

1. eating raw seafood

2. travel

3. gastroenteritis: rice-water stool

4. injury in nature water

Vibrio gram stain morphology

curved or comma-shaped G=

can be pleomorphic

nonsporeforming

flagella

Vibrio interaction with air

facultative anaerobe

Vibrio biochems

• catalase

• oxidase

• nitrate

• string test

• glucose

• urea

• catalase (+)

• oxidase (+)

• nitrate (+)

• string test (+)

• glucose fermenter

• urea (+)

Vibrio drug of choice

doxycycline or ciprofloxacin

Vibrio interaction with temperature, salt, and carbon metabolism

mesophilic, halophilic, chemoorganotrophic

how are Vibrio cholerae and Vibrio mimicus different from usual Vibrio?

they aren’t halphiic

how are Vibrio metschnikovii and Vibrio gazogenes different from regular Vibrio?

catalase (=)

oxidase (=)

Vibrio are [R/S] to O/129?

Susceptible

O/129

vibriostat disk containing 2,4-diamino-6,7-diisopropylpteridine

are Vibrio isolates [S/R] to Vibriostat disks

S

String test

tests bile solubility

emuslifies 2-3 colonies in sodium desoxycholate

how to differentiate Vibrio from Aeromonas?

O/129 susceptibility

Vibrio is S and Aeromonas is R

3 subgroups of Vibrio cholerae

Vibrio cholerae 01 (causative cholera agent)

Vibrio cholerae 0139 (epidemic cholera)

Vibrio cholerae non-O1

which antigens does Vibrio cholerae have?

H and O antigens

what are the 3 Vibrio cholerae O1 subtypes

1. Ogawa (A, B)

2. Inaba (A, C)

3. Hikojima (A, B, C)

what are the 2 Vibrio cholerae O1 biogroups

1. classic

2. El Tor

which Vibrio cholerae subgroup has a milder disease but doesn’t produce cholera toxin?

non-O1

which 2 Vibrio are non-halophilic?

1. Vibrio cholerae

2. Vibrio mimicus

where does much Vibrio cholerae epidmics happen?

developing countries: Bengal region of India and Bangladesh

Cholera

acute diarrheal disease spread through contaminated water and mishandled food

list 3 symptoms of Cholera

Diarrhea caused by toxin :(

1. rice-water stool (watery flecks of mucus)

2. water and electrolyte loss (pooping 10-30x per day)

3. dehydrated, hypovolemic shock, metabolic acidosis —> DEATH

what happens to cholera patient if left untreated?

DEATH

how does Vibrio cholerae enact virulence?

bacteria colonize small intestine and release toxin

how does the cholera enterotoxin work (choleragen) in 3 steps?

1. B subunit binds to GM1 ganglioside receptor

2. A2 subunit allows A1 to enter

3. A1 subunit stimulates adenylate cyclase by inactivating a G protein, activating cAMP

Cholera treatment

Electrolytes: IV and oral fluids

how to differentiate between the 2 Vibrio cholerae 01 biogroups?

Classic: VP (=), nonhemolytic, grows with polymyxin B, does not agglutinate chicken RBC

El Tor: VP (+), hemolytic, inhibited by polymyxin B, agglutinates chicken RBC

Vibrio parahaemolyticus epidemiology

• discovered in Japan (1950)

• “summer diarrhea,” a large food poisoning outbreak

which Vibrio parahaemolyticus serotype emerged after 1996?

O3:K6

where does Vibrio parahaemolyticus like to grow?

1-8% NaCl, associated with seafood and raw oysters

Vibrio parahaemolyticus can be isolated from?

• wound: eye, ear, pneumonia

Vibrio parahaemolyticus drug of choice

Tetracycline

Vibrio parahaemolyticus 3 symptoms and how long after ingestion do you experience them?

• self-limiting watery diarrhea and cramping

• sometimes vomiting

• 24-48 hrs after ingestion

Vibrio parahaemolyticus virulence factors

Kanagawa phenomenon: heat-stabile hemolysin can lyse human cells

what are the 1st and 2nd most common species in gastroenteritis

1. Vibrio cholerae

2. Vibrio parahemolyticus

Vibrio vulnificus epidemiology

atlantic, gulf, and pacific coasts

Vibrio vulnificus AKA

lactose-positive vibrio

what 2 symptoms does Vibrio vulnificus cause?

1. wound infections: traumatic aquatic wound

   -can lead to-

2. septicemia: especially increased serum iron; 40-60% mortaility

Vibrio vulnificus wound infections (cellulitis) can progress to…

necrotizing faciitis or multiple organ system failure

Vibrio cholerae vs Vibrio vulnificus infection

cholerae: make you DIE

vulnificus: septic fluid; fatal within HOURS

which Vibrio is the least pathogenic?

Vibrio alginolyticus

Vibrio alginolyticus causes what types of infections?

extraintestinal: eye, ear, wound, burn

who is at risk with Vibrio alginolyticus infections?

fishermen or sailors

Vibrio plate morphology

SBA/CHOC: medium-large colonies

smooth, opaque, iridescent with greenish hue

Vibrio appearance on MAC plate

Lactose (=)

EXCEPT Vibrio vulnificus

what does TCBS agar do for Vibrio?

Thiosulfate Citrate Bile Sucrose

separates sucrose and nonsucrose-fermenters

other Vibrio: fermenter

Vibrio parahaemolyticus and vulnificus: nonfermenter

Vibrio specimen to collect; and HOW

body fluid, pus, tissue

Swab: Cary-Blair

stool: collected as EARLY as possible

which swab can you NOT use for Vibrio specimen?

buffered glycerol saline

Vibrio 3 non-culture ID methods

• 16S rRNA sequencing: not common, rarely isolated

• Molecular: PFG or REP-PCR

• Serological: polyvalent O1 antiserum

Aeromonas where and when is it found?

freshwater/marine

retail produce and animal meat

May-October (warmer months)

are Aeromonads enteric pathogens?

YES. it relates to the intestines

5 types of Aeromonas associated diarrhea

1. acute secretory diarrhea with vomiting

2. acute dysenteric form with blood and mucus

3. chronic diarrhea >10 days

4. cholera-like, watery-bloody

5. traveler’s diarrhea: nebulous syndrome

Aeromonas extraintestinal infections

wound, septicemia, and MANY more :(

Aeromonas hydrophilia wound infection caused by

leaches during plastic surgery to relieve congestion and swelling

Aeromonas veronii (sobria) septicemia is related with

traumatic injury, immunocompromised, liver disease

Aeromonas two groups

• Mesophilic (37°C): Aeromonas hydrophila, bestiarum, salmonicida

• Psychrophilic (22°C): Aeromonas salmonicida

which group of Aeromonas is motile?

Mesophilic

Aeromonas gram stain morphology

straight, coccobacillary-bacillary GNR

non-spore formers

Aeromonas growth on media?

grows readily, after 24 hr incubation

Aeromonas colony morphology?

large, round, raised, opaque

translucent and white, buff-colored

Aeromonas SBA and MAC growth

SBA: variable hemolysis

MAC: lactose fermenter

Aeromonas biochems

• oxidase

• indole

• string test

• O/129 disk

• 0% NaCl

• inositol fermentation

• oxidase (+)

• indole (+)

• string test (=)

• Vibrostat disk (R)

• 0% NaCl (+)

• inositol fermentation (=)

Aeromonas antibiotics resistant to

penicillin, ampicillin, carbenicillin

Aeromonas antibiotics susceptible to

SMZ, aminoglycosides, quinolones

Aeromonas hydrophilia unique extraintestinal infection

Keratitis: contact lens water

Aeromonas hydrophilia hemolysis

beta hemolysis

Aeromonas caviae vs. Aeromonas hydrophilia

Aeromonas caviae: H2S (=), VP (=)

Aeromonas hydrophilia: H2S (+), VP (+)

Aeromonas veronii vs Aeromonas hydrophilia

Aeromonas veronii: ODC+

Aeromonas hydrophilia: ODC=

where is Aeromonas veronii isolated from?

stool, wound, RT

where is Aeromonas caviae isolated from?

stool, surgical wound, liver abscess

Aeromonas and Plesiomonas vs Vibrio

Aeromonas and Plesiomonads:

string test (=)

NaCl 0%

Vibrio:

string test (+)

NaCl 6%

O/129 (S)

Aeromonas vs Plesiomonas

Aeromonas:

insitol (=)

O/129 (R)

Plesiomonas:

insitol (+)

O/129 (S)

Campylobacter members

Campylobacter jejuni ssp. Jejuni

Campylobacter fetus ssp. fetus

Campylobacter epidemiology

abortion in domestic animals (zoonotic organisms)

Campylobacter 5 methods of transmission

1. direct contact with animals

2. contaminated water/dairy

3. improper poultry cooking

4. person to person

5. STD

Campylobacter relation to air

microaerophilic: need 5% O2

Campylobacter gram stain

nonspore-forming GNR —over time—> coccobacilli

“seagull wing”

poor gram stain

Campylobacter biochem

• oxidase

• catalase

• NaHipp

• fermentation

• incubation temp

• Oxidase (+)

• catalase (+)

• NaHipp (+)

• nonfermenter

• 42°C

Campylobacter motility

darting (seen on wet prep or phase contrast microscopy)

what is the most common diarrheal illness?

Campylobacter jejuni

Campylobacter jejuni symptoms

• diarrhea with mild ab pain: fever, chills

• self-limiting (2-6 days)

• GBS

what specimen is Campylobacter fetus isolated from?

blood cultures

which Campylobacter causes abortions in cattle, sheep, and pigs?

Campylobacter fetus

who tends to get infected with Campylobacter fetus?

immunocompromised and old people

what 3 ways are Campylobacter specimen collected?

1. blood

2. stool

3. rectal swabs (less preferred)

if there is a delay in processing stool specimen for Campylobacter or Vibrio, what transport medium is used?

Cary-Blair

how to grow Campylobacter and Helicobacter isolates?

microaerophilic and capnophilic atmosphere

stool- 42°C

Campylobacter jejuni colony morphology

moist “runny looking” and spreading

nonhemolytic

raised and round/flat

Campylobacter fetus subsp. fetus colony morphology

tan/pink/translucent

smooth, convex

Campylobacter gram stain UNIQUE

use carbol fuchsin as counterstain

if safranin is used: extend 2-3 min

what media can help cultivate Campylobacter?

Skirrow’s and Butzler