MT: NON-ENTERIC GRAM NEGATIVE PATHOGENS Flashcards by JD Dela Cruz

Non-enteric Gram
Negative Pathogens

Vibrio
Campylobacter
Helicobacter
Aeromonas
Plesiomonas

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Vibrio. Can be differentiated from Enterobacteriaceae by:

positive oxidase reaction
presence of polar flagella (Monotrichous)
growth in an alkaline pH (ph 7-9)

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All species except V. cholerae and V. mimicus require increased _____ for growth
🡪HALOPHILIC (“salt-loving”)

sodium chloride

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result of being injured
while in a marine environment

Soft tissue infections

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result of ingesting food
or water containing large numbers of organisms

Gastrointestinal infections

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Short ( 0.5 um by 3.0 um)
gram negative rods
Appear to be comma
shaped on initial isolation

Vibrio

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selective media
use to isolate Vibrio species

Thiosulfate Citrate Bile Salt Agar (TCBS)

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TCBS pH

8.6

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is positive for V. cholera but not
with V. parahaemolyticus

Sucrose fermentation

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in Vibrio, this agar –colorless colonies (slow lactose fermenter)

MacConkey agar

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Vibrio parahaemolyticus – does not ferment
sucrose thats why its colonies are color ___

green

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Vibrio cholerae – ferments
sucrose thats why its colonies are color ___

yellow

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2 groups of Vibrio cholerae base on O antigen

A. O1 group
B. nonO1 group

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O1 group – ___ disease

epidemic disease

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nonO1 group – either ___ disease or are nonpathogenic

sporadic disease

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O1 group. 2 biotypes

El Tor strain
Classical strain

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biotypes - recent pandemic

El Tor strain

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biotypes - pandemic of the past

Classical strain

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3 serotypes – based on ____ differences

antigenic differences

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serotypes - prevalence on the Philippines

Ogawa

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serotypes - India

Inaba

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serotypes - Japan

Hikojima

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Produces choleragenic toxin
Cultured on Alkaline Peptone Water (APW) and
TCBS
Causes Cholera with a characteristic “rice watery
stool”

Vibrio cholerae

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V. cholerae. POSITIVE on a String Test: Reagent is ___

0.5% Na Deoxycholate

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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

1. proton pump inhibitors (PPI), 2. clarithromycin 3. 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:

1. EMB 2. MacConkey Agar 3. Salmonella-Shigella agar 4. Cefsulodin-Irgasan-Novobiosin

Plesiomonas most common specie

Plesiomonas shigelloides

Gram-negative, rod-shaped bacterium which has been isolated from freshwater Important in Japan as a cause of Gastritis

Plesiomonas

Cannot tolerate SALTWATER due to high salt content (>4%) grows optimally between 35°C and 39°C

Plesiomonas