Non-enteric Gram Negative Pathogens Flashcards
Non-enteric Gram
Negative Pathogens
Vibrio
Campylobacter
Helicobacter
Aeromonas
Plesiomonas
Vibrio. Can be differentiated from Enterobacteriaceae by:
- positive oxidase reaction
- presence of polar flagella (Monotrichous)
- growth in an alkaline pH (ph 7-9)
All species except V. cholerae and V. mimicus require increased _____ for growth
🡪HALOPHILIC (“salt-loving”)
sodium chloride
result of being injured
while in a marine environment
Soft tissue infections
result of ingesting food
or water containing large numbers of organisms
Gastrointestinal infections
- Short ( 0.5 um by 3.0 um)
gram negative rods - Appear to be comma
shaped on initial isolation
Vibrio
selective media
use to isolate Vibrio species
Thiosulfate Citrate Bile Salt Agar (TCBS)
TCBS pH
8.6
is positive for V. cholera but not
with V. parahaemolyticus
Sucrose fermentation
in Vibrio, this agar –colorless colonies (slow lactose fermenter)
MacConkey agar
Vibrio parahaemolyticus – does not ferment
sucrose thats why its colonies are color ___
green
Vibrio cholerae – ferments
sucrose thats why its colonies are color ___
yellow
2 groups of Vibrio cholerae base on O antigen
A. O1 group
B. nonO1 group
O1 group – ___ disease
epidemic disease
nonO1 group – either ___ disease or are nonpathogenic
sporadic disease
O1 group. 2 biotypes
El Tor strain
Classical strain
biotypes - recent pandemic
El Tor strain
biotypes - pandemic of the past
Classical strain
3 serotypes – based on ____ differences
antigenic differences
serotypes - prevalence on the Philippines
Ogawa
serotypes - India
Inaba
serotypes - Japan
Hikojima
Produces choleragenic toxin
Cultured on Alkaline Peptone Water (APW) and
TCBS
Causes Cholera with a characteristic “rice watery
stool”
Vibrio cholerae
V. cholerae. POSITIVE on a String Test: Reagent is ___
0.5% Na Deoxycholate
Intestinal infection causing PROFUSE WATERY DIARRHEA
Can be Endemic, Epidemic or Pandemic
Cholera
the principal ones associated with epidemic cholera
V cholerae O1 and V cholerae O139
Cholera.___ and ___ are mainly affected; L. Intestine not affected
Duodenum and upper jejunum
Cholera. Incubation period – hours or days with a mean
2 to 3 days
Cholera Fluid losses
15 to 20 L per day
V. cholerae. Smears – ___ or ____ microscopy
Dark field or phase contrast microscopy
Treatment cholera
Rehydration/Fluid loss Replacement
Antibiotic: Doxycycline, Azithromycin, Ciprofloxacin
Oral feeding continues
A marine organism transmitted by ingestion raw or
undercooked seafood, especially shellfish such as
oysters
Vibrio parahaemolyticus
A major cause of diarrhea in Japan where raw fish
is eaten in large quantities
Vibrio parahaemolyticus
Little is known about the pathogenesis except that
an enterotoxin similar to cholera is secreted and
little invasion sometimes occurs
Vibrio parahaemolyticus
Non sucrose fermenter 🡪 green colonies on
TCBS
Halophilic and non hemolytic on BAP
Vibrio parahaemolyticus
Also a marine organism, ie, it is found in warm salt waters such as the Caribbean sea, Causes severe skin and soft tissue infections (cellulitis) especially in shellfish handlers, who
often sustain wounds
Vibrio vulnificus
Can also cause a rapidly fatal septicemia in
immunocompromised people who have eaten raw
shellfish containing the organism
Vibrio vulnificus
- Non sucrose fermenter 🡪 green colonies
on TCBS - Lactose fermenter
- ONPG positive (ortho-Nitrophenyl-
β-galactoside) to test the presence of
beta Galactosidase
Vibrio vulnificus
Vibrio vulnificus. ONPG positive. ONPG means
ortho-Nitrophenyl-
β-galactoside
Small, thin, helical, gram-negative rod. “sea-gull” wing appearance
Campylobacter
Campylobacter. Optimum temp for growth:
42-43C
Campylobacter. Microaerophilic & capnophilic. Percentages?
5%O2, 10%CO2, 85%N2
Campylobacter. Distinctive rapid ____ MOTILITY
DARTING MOTILITY
Campylobacter. Selective Culture medium:
CAMPY’S BAP and
SKIRROWS
Campylobacter. Zoonotic infections in many animals particularly
avian (bird) reservoirs
Inflammatory process consistent with invasion of the
organisms into the intestinal tissue; M-cell (Peyer’s
patches) uptake and presentation of antigen to underlying
lymphatic system
Campylobacter
Putative Virulence Factors
Cellular components:
Endotoxin
Flagellum: Motility
Adhesins: Mediate attachment to mucosa
Invasins
Putative Virulence Factors
Extracellular components:
Enterotoxins
Cytopathic toxins
Guillain-Barre Syndrome (GBS)
associated with
C. jejuni serogroup O19
Autoimmune disease in which one’s Immune System attack his own NERVES
Guillain-Barre Syndrome (GBS)
Lab Identification. Hippurate hydrolysis. Susceptibility to nalidixic acid & cephalothin
Campylobacter jejuni
Gastroenteritis treatment
Erythromycin, Azithromycin
Guillain-Barre Syndrome (GBS), Treatment
Intensive-care unit for 33% of cases
Intravenous Immunoglobulins therapy
Helicobacter. First observed in
1983
Helicobacter old name
Campylobacter pyloridis
First observed in 1983 as Campylobacter-like
organisms in the stomachs of patients with type B gastritis
Helicobacter
Helicobacter was first established in
1989
Helicobacter. (male homosexuals; rodents)
H. cinaedi, H. fenneliae
Associated with Peptic Ulcer Disease
Natural habitat is the human stomach; found in the
mucus secreting cells
Helicobacter pylori
Helicobacter pylori. Uses acid neutralization by ___ to combat gastric acidity, allowing gastric colonization
UREASE
Helicobacter pylori shape and size
Helical (spiral or curved) (0.5-1.0
um X 2.5-5.0 um);
Helicobacter pylori Produce
urease, mucinase, and catalase
___ tuft (lophotrichous) of 4-6 sheathed
flagella (30um X 2.5nm) attached at one pole
H. pylori
Most gastric adenocarcinomas and lymphomas are concurrent with or preceded by an infection
with
H. pylori
H. pylori. Culture media containing __ or __ blood
whole or lysed
Microaerophilic
Grow well at 37oC, but not at 25 nor 42oC
Like Campylobacter, does not use carbohydrates,
neither fermentatively nor oxidatively
H. pylori.
Test for H. pylori
Urease Breath Test
H. pylori. Triple Therapy Regimen
- proton pump inhibitors (PPI),
- clarithromycin
- amoxicillin or metronidazole
Gr (-) bacilli FACULTATIVE ANAEROBE
OXIDASE POSITIVE
Generally motile with MONOTRICHOUS FLAGELLA
Aeromonas
Found in fresh water and sea water 🡪 causes disease in
cold blooded animals
In Humans, causes gastroenteritis, cellulitis and wound infections from contaminated water
Aeromonas
Aeromonas. Culture media:
- EMB
- MacConkey Agar
- Salmonella-Shigella agar
- Cefsulodin-Irgasan-Novobiosin
Pleiomonas most common specie
Pleiomonas shigelloides
Gram-negative, rod-shaped bacterium which has been
isolated from freshwater
Important in Japan as a cause of Gastritis
Pleiomonas
Cannot tolerate SALTWATER due to high salt content
(>4%)
grows optimally between 35°C and 39°C
Pleiomonas
