Non-Fermentative Gram-Negative Bacilli Overview
48 Questions
2 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the result of the vibrostatic test for Aeromonas?

  • Positive for lactose fermentation
  • Negative (correct)
  • Negative for oxidase
  • Positive for glucose fermentation

Which group of Aeromonas has an optimal growth temperature around 37 degrees Celsius?

  • Psychrophilic group
  • Mesophilic group (correct)
  • Thermophilic group
  • Extremophilic group

What characteristic is shared by all members of the mesophilic group of Aeromonas?

  • Motile by means of a single polar flagellum (correct)
  • Non-motile
  • Psychrophilic
  • Oxidase-negative

Which of the following is true about V.cholerae 01 based on the description provided?

<p>It is susceptible to vibrostatic testing. (A)</p> Signup and view all the answers

What type of environments are vibrios typically found in?

<p>Freshwater, estuarine, and marine environments (A)</p> Signup and view all the answers

Which species is classified under the psychrophilic group of Aeromonas?

<p>Aeromonas salmonicida (D)</p> Signup and view all the answers

What is a common testing method for differentiating Vibrio species?

<p>Sodium chloride growth test (B)</p> Signup and view all the answers

What is a characteristic of Aeromonas species regarding their oxidase reaction?

<p>They are oxidase-positive. (B)</p> Signup and view all the answers

What is the significance of pseudoalcaligenes being ADH positive?

<p>It suggests acid production from xylose. (D)</p> Signup and view all the answers

Which species is associated with catheter-related sepsis in cancer patients?

<p>Pseudomonas putida (A)</p> Signup and view all the answers

What type of growth do both Pseudomonas fluorescence and Pseudomonas putida exhibit?

<p>Non-fermentative, oxidase-negative bacilli (D)</p> Signup and view all the answers

What is a common risk factor for infections caused by Pseudomonas species?

<p>Use of corticosteroids (B)</p> Signup and view all the answers

What test can be used to differentiate between Pseudomonas species?

<p>ONPG and esculin hydrolysis test (D)</p> Signup and view all the answers

What type of pigment is often produced by Pseudomonas fluorescence?

<p>Yellow intracellular non-diffusible pigment (D)</p> Signup and view all the answers

Which statement about the virulence of Pseudomonas fluorescence and Pseudomonas putida is accurate?

<p>They exhibit moderate virulence under special conditions. (B)</p> Signup and view all the answers

Which clinical conditions have Pseudomonas fluorescence and putida been documented as causes?

<p>Wound infections and urinary tract infections (C)</p> Signup and view all the answers

What is a characteristic colony appearance of Burkholderia pseudomallei?

<p>Wrinkled colony (D)</p> Signup and view all the answers

Which medium is specifically recommended for the growth of Burkholderia pseudomallei?

<p>Ashdown medium (C)</p> Signup and view all the answers

What is the primary virulence factor of Vibrio species discussed in the content?

<p>Cholera toxin (B)</p> Signup and view all the answers

Which of the following morphological characteristics do all Vibrio species share?

<p>Curved or comma-shaped rods (B)</p> Signup and view all the answers

What type of physiological trait allows Vibrio species to attach to mucosal cells?

<p>Toxin-co-regulated pili (C)</p> Signup and view all the answers

How does Burkholderia pseudomallei primarily enter the body?

<p>By ingestion, inhalation, or inoculation (B)</p> Signup and view all the answers

What specific feature helps Vibrio species distribute along the gastrointestinal tract?

<p>Motility and chemotaxis (C)</p> Signup and view all the answers

Which of the following statements is correct regarding the colonies of Burkholderia pseudomallei on Ashdown medium?

<p>Colonies have a deep pink color (B)</p> Signup and view all the answers

Which serotypes of Vibrio are almost always associated with cholera toxin production?

<p>O1 and O139 (A)</p> Signup and view all the answers

What is the common route through which cholera is transmitted?

<p>Fecal-oral route (B)</p> Signup and view all the answers

What does the term 'viable but not culturable' refer to in relation to Bacillus?

<p>Cells that remain dormant yet alive (C)</p> Signup and view all the answers

Which toxin is produced by clinical strains of Vibrio parahaemolyticus that can lyse human erythrocytes?

<p>Kanagawa toxin (D)</p> Signup and view all the answers

What environmental conditions allow Bacillus to survive for a long time?

<p>Brackish or saltwater environments (A)</p> Signup and view all the answers

Which of the following is NOT a virulence factor of cholera-causing strains?

<p>Heat-stable hemolysin (B)</p> Signup and view all the answers

Which type of seafood is particularly associated with the Kanagawa phenomenon?

<p>Improperly cooked or decontaminated seafood (B)</p> Signup and view all the answers

What is a common characteristic of Vibrio parahaemolyticus under dark field microscopy?

<p>Rapid darting or shooting-star motility (D)</p> Signup and view all the answers

What is the most common presentation of Aeromonas hydrophila infection?

<p>Cellulitis (D)</p> Signup and view all the answers

Which species is most strongly associated with Aeromonas sepsis?

<p>Aeromonas veronii biovar sobria (B)</p> Signup and view all the answers

What type of media allows for the growth of Aeromonas species without NaCl?

<p>Nutrient broth (A)</p> Signup and view all the answers

Which of the following characteristics differentiates Campylobacter species from Vibrios?

<p>Oxygen requirements (D)</p> Signup and view all the answers

In the context of Aeromonas infections, what common exposure is associated with wound infections?

<p>Traumatic aquatic exposure (D)</p> Signup and view all the answers

Which test is especially useful for separating Aeromonas from Yersinia?

<p>Oxidase test (A)</p> Signup and view all the answers

Aeromonas species are generally classified based on which type of morphology?

<p>Curved shaped bacilli (C)</p> Signup and view all the answers

What is a notable trait of Aeromonas hydrophila in culture media?

<p>Positive for indole (A)</p> Signup and view all the answers

What must be used to culture Campylobacter jejuni from stool samples?

<p>Stuart medium (A), Chocolate agar (C)</p> Signup and view all the answers

What is the ideal incubation temperature for recovering Campylobacter jejuni from stool cultures?

<p>42°C (D)</p> Signup and view all the answers

Which gas mixture is optimal for the microaerophilic environment needed for Campylobacter?

<p>5% oxygen, 10% carbon dioxide, 85% nitrogen (B)</p> Signup and view all the answers

Why is it important for the inoculated medium to be fresh and moist?

<p>To enhance bacterial growth (B)</p> Signup and view all the answers

What is the primary characteristic tested to identify Campylobacter?

<p>Heparin hydrolysis (D)</p> Signup and view all the answers

What environment is required for Enteric Campylobacter and Helicobacter species?

<p>Microaerophilic and capnophilic (B)</p> Signup and view all the answers

What is the correct way to store tissue samples for Campylobacter identification?

<p>In cysteine-Brucella broth with 20% glycerol at -70°C (D)</p> Signup and view all the answers

What temperature range is used for the differentiation of Campylobacter species?

<p>25-42°C (D)</p> Signup and view all the answers

Flashcards

Pseudomonas fluorescence/putida

Gram-negative, non-fermentative bacteria that are catalase positive, motile; able to oxidize glucose; and grow on MacConkey agar. Produce yellow pigment.

Pseudoalcaligenes

A genus of bacteria that is ADH positive; weakly ferments xylose and fructose; and does not produce pigments or grow at 42°C.

Low virulence

Pseudomonas fluorescence and putida generally cause few clinical issues.

Clinical disease

Specific illnesses caused by bacteria like Pseudomonas that can be observed.

Signup and view all the flashcards

Risk factors (Pseudomonas)

Factors that increase the chance of infection with Pseudomonas, such as foreign materials, corticosteroid use, and weakened immune systems.

Signup and view all the flashcards

Sepsis

A life-threatening inflammatory response to infection that can lead to tissue damage.

Signup and view all the flashcards

Differential Diagnosis (Pseudomonas)

Using tests like ONPG and esculin hydrolysis to tell apart similar Pseudomonas species.

Signup and view all the flashcards

Polyenes

Wrinkled yellow colonies produced by Pseudomonas on agar.

Signup and view all the flashcards

Vibrio differentiation

Differentiating Vibrio from Aeromonas based on growth in salt and acid production from sugars.

Signup and view all the flashcards

Vibrio susceptibility

Vibrio species are susceptible to certain selective pressures in certain tests.

Signup and view all the flashcards

Aeromonas test result

Aeromonas will give a negative result in the Vibrio test.

Signup and view all the flashcards

Vibrio characteristics

Gram-negative rods, oxidase-positive, and glucose fermenting.

Signup and view all the flashcards

Aeromonas group types

Categorized by temperature preference into mesophilic and psychrophilic groups.

Signup and view all the flashcards

Mesophilic group growth

Ideal growth temperature for Aeromonas species is around 37 degrees Celsius.

Signup and view all the flashcards

Motility in Aeromonas

Aeromonas motile by a single polar flagellum.

Signup and view all the flashcards

Aeromonas environments

Found in fresh, estuarine, and marine waters; also retail produce and animal products.

Signup and view all the flashcards

Burkholderia pseudomallei

A gram-negative bacterium causing melioidosis, a disease characterized by pulmonary infection and abscess formation.

Signup and view all the flashcards

Melioidosis

A severe, often fatal pulmonary disease caused by Burkholderia pseudomallei.

Signup and view all the flashcards

Gram-negative bacilli

A diverse group of bacteria categorized by their cell wall structure and shape, often associated with various diseases.

Signup and view all the flashcards

Cholera toxin

A potent toxin produced by Vibrio species, leading to severe dehydration in cholera patients.

Signup and view all the flashcards

Vibrio

A genus of gram-negative, curved or comma-shaped rods, causing infections like cholera.

Signup and view all the flashcards

Ashdown medium

A selective medium used to cultivate Burkholderia species, which produces a deep pink color.

Signup and view all the flashcards

Bipolar staining

A staining method in which Burkholderia pseudomallei displays two staining poles.

Signup and view all the flashcards

Wrinkled colonies

A visual characteristic of certain bacterial colonies, appearing with irregular, bumpy surfaces

Signup and view all the flashcards

Cholera toxin

A toxin produced by certain strains of Vibrio cholerae that causes cholera.

Signup and view all the flashcards

O1 and O139 strains

Specific strains of Vibrio cholerae that almost always produce cholera toxin.

Signup and view all the flashcards

Non-O1/Non-O139 strains

Vibrio cholerae strains that do not produce cholera toxin; associated with non-epidemic diarrhea.

Signup and view all the flashcards

Kanagawa phenomenon

The ability of some Vibrio parahaemolyticus strains to lyse human red blood cells in a specific medium (Wagatsuma agar).

Signup and view all the flashcards

Vibrio parahaemolyticus

A Vibrio species frequently causing gastroenteritis, often from consuming raw seafood.

Signup and view all the flashcards

Gram-negative

A bacterial characteristic, where the cell has a thin peptidoglycan layer and outer membrane.

Signup and view all the flashcards

Fecal-oral route

The primary mode of transmission of certain bacterial pathogens, through contaminated food and water.

Signup and view all the flashcards

Dormant stage

A stage of bacteria where they're alive but not actively dividing or growing, capable of long-term survival in certain environments.

Signup and view all the flashcards

Aeromonas Infections

Common infections often linked to aquatic exposure, typically presenting as cellulitis or sepsis, particularly in immunocompromised individuals.

Signup and view all the flashcards

Aeromonas Sepsis

A serious invasive infection linked to certain Aeromonas species (A.veroni, A.jandaei, and A.hydrophila) and often associated with immunocompromised patients

Signup and view all the flashcards

Wound Infections (Aeromonas)

Aeromonas infections are often linked to recent injury involving aquatic environments like boating.

Signup and view all the flashcards

Aeromonas Culture Media

Aeromonas species commonly exhibit strong Beta-hemolysis, ferment lactose, and may resemble Yersinia on certain media.

Signup and view all the flashcards

Oxidase Test (Aeromonas)

Used to differentiate Aeromonas species from Yersinia, where Aeromonas are positive and Yersinia are negative in oxidase tests.

Signup and view all the flashcards

NaCl Tolerance (Aeromonas)

Aeromonas bacteria grow well in low concentrations of salt but not in high concentrations of NaCl, unlike some Vibrio species.

Signup and view all the flashcards

Glucose Fermentation

Aeromonas species can ferment glucose; the presence or absence of gas can serve as a differential factor along with other tests for identification

Signup and view all the flashcards

Aeromonas Differentiation

Difficulties in identification often arise as Aeromonas and Yersinia may have similar characteristics on certain culture media

Signup and view all the flashcards

Campylobacter recovery temperature

Stool cultures of Campylobacter should be incubated at 42°C to maximize Campylobacter jejuni recovery.

Signup and view all the flashcards

Campylobacter fetus subsp. fetus growth temp.

Incubation at 37°C is necessary for Campylobacter fetus subsp. fetus growth.

Signup and view all the flashcards

Campylobacter culture media

A combination of non-selective media (e.g., chocolate agar, Brucella agar) and selective media (e.g., Skirrow agar) are used for Campylobacter.

Signup and view all the flashcards

Helicobacter incubation gas mixture

Ideal atmospheric environment for Helicobacter is 5% to 10% oxygen, 5% to 12% carbon dioxide, and 85% to 80% nitrogen.

Signup and view all the flashcards

Microaerophilic environment

A low oxygen atmosphere (typically less than 5% oxygen) needed for the growth of some bacteria like Campylobacter and Helicobacter.

Signup and view all the flashcards

Positive urease test

A key characteristic for identifying Helicobacter pylori.

Signup and view all the flashcards

Stool samples for Campylobacter

For recovering Campylobacter from stool, a combination of non-selective media like chocolate or Brucella agar and 5% horse red blood cells and a selective medium like Skirrow agar.

Signup and view all the flashcards

H.pylori specimen material

Gastric biopsy materials are needed to test for the presence of Helicobacter pylori.

Signup and view all the flashcards

Study Notes

Non-Fermentative Gram-Negative Bacilli

  • Gram-negative bacilli can be aerobic or obligate anaerobic
  • Fermentative bacteria ferment carbohydrates
  • Non-fermentative bacteria do not ferment carbohydrates
  • Ubiquitous in soil, water, plants, decaying vegetation, and foods.
  • Prefer moist environments
  • Found in hospitals: nebulizers, dialysate, fluids, saline, catheters
  • Can withstand chlorhexidine and quaternary ammonium compounds

General Characteristics

  • Aerobic
  • Non-spore forming
  • Straight or slightly curved
  • Slender
  • Motile except Burkholderia mallei
  • Pseudomonas and Burkholderia are oxidase positive
  • Members utilize carbohydrates, alcohols, amino acids for energy
  • Some oxidize carbohydrates
  • Oxidizers exhibit K/K on TSI (alkaline slant/alkaline butt)
  • Non-oxidizers do not break down carbohydrates
  • Motility, pigmentation, and selective media differentiate non-fermenters

Pseudomonas

  • Gram-negative bacilli or coccobacilli
  • Strictly aerobic
  • Usually motile with polar flagella
  • Oxidase positive (except P. luteolus and P. oryzihabitans)
  • Catalase positive
  • Usually grows on MAC agar
  • Usually an oxidizer of carbohydrates (but some are not)
  • Pseudomonas aeruginosa is common in moist environments (pools, hot tubs, catheters, humidifiers)
  • Opportunistic pathogen
  • Virulence factors: exotoxin A, exoenzymes S and T, proteolytic enzymes (e.g., elastases), hemolysins (e.g., phospholipase C), pili, adhesins, and alginate.
  • Associated with nosocomial respiratory tract infections, bacteremia, wound infections, and CF lung infections.

Other Pseudomonas species

  • P. fluorescens produces acid from xylose, is oxidase positive, and ADH positive, but does not produce pyoverdin
  • P. putida: produces acid from xylose, pigment production negative, growth at 42°C negative and negative gelatin hydrolysis
  • P. mendocina: nonwrinkled colonies, may be yellowish-brown pigment, smooth buttery appearance
  • P. stutzeri: wrinkled, leathery, adherent colonies, may produce a light yellow or brown pigment; ADH negative and starch hydrolysis positive
  • P. pseudoalcaligenes and P. alcaligenes: contaminants, oxidase positive, and ADH positive but does not produce pyoverdin and is acetamide negative

Acinetobacter

  • Gram-negative, non-fermentative, oxidase negative, and catalase positive bacilli
  • Motile, able to oxidize glucose, and grow on MacConkey agar.
  • Often produces an intracellular non-diffusible yellow pigment
  • A. baumannii: glucose-oxidizing, nonhemolytic
  • A. Iwoffii: glucose-negative, nonhemolytic
  • Associated with ventilators, humidifiers, catheters, and water
  • Common cause of hospital infections

Burkholderia

  • Aerobic, non-spore-forming, straight, or slightly curved, slender gram-negative bacilli (motile except Burkholderia mallei)
  • B. cepacia: lose viability on SBA in 3 to 4 days; non-fluorescing yellow or green pigment; less likely to be mistaken for P. stutzeri, which is also a yellow pigment producer
  • B. pseudomallei: aggressive pulmonary disease with the formation of abscesses and spread to other organs; characteristically stains bipolarly (two prominent colors across the cell)

Vibrio

  • Gram-negative, facultative anaerobic, curved or commashaped rods
  • Require sodium for growth and glucose fermentation
  • Usually motile and catalase and oxidase positive
  • Primary habitats are brackish or marine water (for Vibrio spp.)
  • Transmitted through ingesting contaminated water, fresh produce, meat, or seafood.
  • Common causes of epidemics and pandemics of diarrheal disease (cholera)
  • V. cholerae: causes cholera, with its main virulence factor being cholera toxin (CT)
  • V. parahaemolyticus: common cause of gastroenteritis in Japan; associated with eating raw or improperly cooked seafood
  • V. vulnificus: often associated with consuming shellfish, especially oysters; can lead to serious infections, especially in individuals with liver disease

These notes summarize and condense the information, without repetition.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Non-Fermentative Gram-Negative Bacilli PDF

Description

This quiz covers the characteristics and classification of non-fermentative gram-negative bacilli, including important genera such as Pseudomonas and Burkholderia. Focused on their environmental prevalence, metabolic processes, and hospital-related occurrences, the quiz will test your understanding of these microorganisms. Perfect for microbiology students seeking to deepen their knowledge on this topic.

More Like This

Dairy Defects in Fermentation
10 questions

Dairy Defects in Fermentation

AmazedTurkey avatar
AmazedTurkey
Fermentation Processes Quiz
37 questions

Fermentation Processes Quiz

BriskSanAntonio4600 avatar
BriskSanAntonio4600
Dairy Science: Lactose Fermentation and Bacteria
45 questions

Dairy Science: Lactose Fermentation and Bacteria

InnovativeFlugelhorn8365 avatar
InnovativeFlugelhorn8365
Use Quizgecko on...
Browser
Open
Browser
Browser