Gram-Negative Coccobacilli Overview
30 Questions
0 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

Which factor attributed to the virulence of Haemophilus influenzae is responsible for its antiphagocytic properties?

  • LPS (lipopolysaccharide)
  • IgA1 protease
  • Pili and nonpilus adhesin
  • Polyribitol phosphate (PRP) capsule (correct)

    • What is the primary reservoir for Haemophilus influenzae infections?

  • Soil
  • Insects
  • Humans (correct)
  • Animals

    • Which of the following species is included in the genus Bordetella?

  • Haemophilus influenzae
  • B. parainfluenzae
  • B. pertussis (correct)
  • Brucella abortus

    • What type of growth medium is specifically required for culturing Haemophilus influenzae?

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

    Which clinical condition is commonly associated with the spread of Haemophilus influenzae?

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

    What factor primarily facilitates the attachment of Haemophilus influenzae to the respiratory epithelial cells?

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

    Which of the following describes the shape and gram characterization of Haemophilus influenzae?

    <p>Coccobacillus, Gram-negative (A)</p> Signup and view all the answers

    Which virulence factor of Haemophilus influenzae is involved in causing fever and inflammation?

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

    What is the main route of transmission for Haemophilus influenzae?

    <p>Aerosolized droplets (B)</p> Signup and view all the answers

    Which subtype of Haemophilus influenzae is most notorious for infecting children and immunocompromised individuals?

    <p>Type b (C)</p> Signup and view all the answers

    What is the primary source of transmission of Brucella to humans?

    <p>Consumption of uncooked animal-derived food products (B)</p> Signup and view all the answers

    Which of the following conditions is NOT associated with unencapsulated strains of Haemophilus influenzae?

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

    Which of the following is NOT a characteristic of brucellosis?

    <p>All age groups are immune to the disease (C)</p> Signup and view all the answers

    What is the most common serological test used for diagnosing brucellosis?

    <p>Rose Bengal Test (RBT) (C)</p> Signup and view all the answers

    What type of pathogen is Brucella, and what is its primary mode of transmission?

    <p>Facultative intracellular; zoonotic transmission (A)</p> Signup and view all the answers

    Which of the following is true regarding Bordetella pertussis culture?

    <p>Requires a CO2-rich atmosphere for growth (B)</p> Signup and view all the answers

    How often should blood cultures be carried out when diagnosing brucellosis in its acute phase?

    <p>Repeatedly due to intermittent entry into the blood (A)</p> Signup and view all the answers

    Which drug combination is considered the treatment of choice for brucellosis?

    <p>Tetracycline and Rifampin (B)</p> Signup and view all the answers

    Haemophilus influenzae type b septicemia can lead to which of the following severe complications?

    <p>Severe vasculitis (B)</p> Signup and view all the answers

    Which clinical manifestation is most characteristic of human brucellosis?

    <p>Acute febrile illness (C)</p> Signup and view all the answers

    What percentage of blood cultures are positive in the early weeks of brucellosis infection?

    <p>30-50% (A)</p> Signup and view all the answers

    Which method is used to demonstrate the presence of Brucella organisms in clinical specimens?

    <p>Fluorescent antibody technique (D)</p> Signup and view all the answers

    What is the typical morphology of Brucella species?

    <p>Gram-negative coccobacilli, non-motile (D)</p> Signup and view all the answers

    Which population is primarily affected by whooping cough caused by Bordetella pertussis?

    <p>Non-immune children (B)</p> Signup and view all the answers

    Which population is least likely to be affected by brucellosis due to occupational exposure?

    <p>Office workers with no contact with animals (A)</p> Signup and view all the answers

    What distinguishes Brucella colonies during culture from standard laboratory bacteria?

    <p>They are fastidious and usually not visible until after 3-5 days (D)</p> Signup and view all the answers

    What is a rare mode of transmission for Brucella infection?

    <p>Inhalation of aerosols (B)</p> Signup and view all the answers

    What is an effective prophylactic treatment for Bordetella pertussis exposure?

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

    What is the significant titer value in the Rose Bengal Test for diagnosing brucellosis?

    <p>1/160 or higher (A)</p> Signup and view all the answers

    Which of the following infections is associated with encapsulated strains of Haemophilus influenzae?

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

    Flashcards

    Haemophilus influenzae

    A gram-negative coccobacillus bacterium often causing respiratory infections.

    Gram-negative coccobacillus

    A bacterial shape, rod-like but slightly oval, and gram-negative.

    Satellitism

    Haemophilus's dependence on other bacteria for growth.

    Growth Factors X and V.

    Essential growth factors Haemophilus needs for growth in lab.

    Signup and view all the flashcards

    Polyribitol phosphate (PRP) capsule

    A protective layer preventing phagocytosis of Haemophilus bacteria.

    Signup and view all the flashcards

    Endotoxin (LPS)

    A component of the outer membrane of gram-negative bacteria.

    Signup and view all the flashcards

    Transmission of Haemophilus

    Close contact and respiratory droplets are ways of spreading Haemophilus.

    Signup and view all the flashcards

    Hib

    Haemophilus influenzae type b; a significant cause of serious infection in children.

    Signup and view all the flashcards

    Reservoir (Haemophilus)

    Humans serve as the primary source of Haemophilus.

    Signup and view all the flashcards

    Virulence factors

    Factors that contribute to a pathogen's ability to cause disease.

    Signup and view all the flashcards

    Haemophilus influenzae infections

    Bacterial infections caused by Haemophilus influenzae bacteria. Can lead to serious illnesses like pneumonia, meningitis, and sepsis in young children.

    Signup and view all the flashcards

    Encapsulated strains of Haemophilus influenzae

    These strains are more likely to cause serious illnesses, particularly in young children.

    Signup and view all the flashcards

    Bordetella pertussis

    The bacterium responsible for whooping cough.

    Signup and view all the flashcards

    Whooping cough

    An infectious respiratory disease caused by Bordetella pertussis.

    Signup and view all the flashcards

    Brucellosis

    A zoonotic disease, meaning it can be transmitted from animals to humans, usually caused by Brucella bacteria.

    Signup and view all the flashcards

    Zoonotic disease

    A disease naturally transmitted from animals to humans.

    Signup and view all the flashcards

    Brucella spp.

    A genus of bacteria responsible for brucellosis.

    Signup and view all the flashcards

    Facultative intracellular pathogen

    A pathogen that can live and multiply both inside and outside host cells.

    Signup and view all the flashcards

    Morphology

    Describing the microscopic and macroscopic characteristics of a biological structure

    Signup and view all the flashcards

    Brucellosis Transmission

    Humans typically acquire Brucellosis through occupational or environmental exposure to infected animals or their products, such as milk, meat, or animal hides.

    Signup and view all the flashcards

    Brucellosis Symptoms

    Symptoms of Brucellosis can vary widely and include fever, chills, sweating, muscle aches, joint pain, fatigue, and headache. The infection can affect various organ systems.

    Signup and view all the flashcards

    Brucellosis Diagnosis

    Diagnosis of Brucellosis involves laboratory tests, such as blood cultures, serological tests (like the Rose Bengal Test or Standard Tube Agglutination Test), and fluorescent antibody staining to identify the bacteria.

    Signup and view all the flashcards

    Brucellosis Treatment

    The primary treatment for Brucellosis is a combination of antibiotics, usually tetracycline and rifampin, taken for an extended period.

    Signup and view all the flashcards

    Brucellosis Complications

    Untreated Brucellosis can lead to complications affecting various organ systems, including the joints, heart, liver, and nervous system.

    Signup and view all the flashcards

    Brucella melitensis

    A specific species of Brucella bacteria, commonly found in goats and sheep, and a major cause of brucellosis in humans.

    Signup and view all the flashcards

    Macrophages

    White blood cells that engulf and destroy pathogens in the body, playing a crucial role in the immune system.

    Signup and view all the flashcards

    Rose Bengal Test (RBT)

    A rapid, widely used serological test for detecting antibodies against Brucella in blood. It is known for its sensitivity and is often used in the initial screening of brucellosis.

    Signup and view all the flashcards

    Standard Tube Agglutination Test (STAT)

    A serological test that measures the ability of antibodies in blood to agglutinate (clump together) Brucella antigens. It helps confirm and quantify Brucella antibodies.

    Signup and view all the flashcards

    Study Notes

    Gram-Negative Coccobacilli

    • Gram-negative coccobacilli include Haemophilus, Bordetella, and Brucella.
    • They share similar bacterial shape and Gram stain.
    • However, they differ in the diseases they cause, populations they affect, virulence factors, pathogenesis, and ability to infect animals and humans.
    • There are different species present within each genus.
    • Haemophilus influenzae is a common species (blood lover), with subtypes like H. parainfluenzae

    Haemophilus influenzae

    • Morphology: Gram-negative coccobacillus, measuring 1 μm.

    • Cultivation: Requires growth factors (X = Haem, V = NAD) on chocolate agar. A characteristic feature is satellitism, where Haemophilus colonies grow around other bacteria.

    • Virulence factors: PRP (polyribitol phosphate) capsule (antiphagocytic), LPS (endotoxin – causes fever and inflammation, impairs respiratory epithelial cell ciliary function), IgA1 protease (colonization), pili and non-pilus adhesins (colonization of oropharynx), survival in respiratory epithelial cells.

    • Reservoir and Transmission: Humans (mostly endogenous/exogenous), via close contact with respiratory droplets.

    • Infection involves attachment to cells in the upper respiratory tract (via fimbriae and IgA1 protease), endotoxin disabling respiratory cilia from cleaning the bacteria, leading to local spread (ears, sinuses, lungs, soft tissues) or systemic spread (blood and brain).

    • Classified in encapsulated and non-encapsulated types.

    • Encapsulated H. influenzae type b (Hib) is a significant cause of infections like bacteremia, meningitis, epiglottitis, and cellulitis in children.

    Bordetella pertussis

    • Morphology: Gram-negative coccobacillus.
    • Cultivation: Requires special media (Bordet-Gengou agar)
    • Adhesins (colonisation): Filamentous hemagglutinin (FHA), Pertactin, Fimbriae, Pertussis toxin.
    • Toxins: Pertussis toxin, Adenylate cyclase toxin, Dermonecrotic toxin (DNT), Tracheal cytotoxin, and LPS (endotoxin).
    • Whooping cough: Primarily affects non-immune children, adults with waning immunity can have milder forms.
    • Clinical Course: Incubation (5-10 days, max 21), catarrhal (1-2 weeks – common cold-like symptoms), paroxysmal (1-6 weeks – severe coughing fits), and convalescent (weeks to months).

    Brucella & Brucellosis

    • Zoonosis: Animal disease transmittable to humans. Brucella species are the causative agents of brucellosis.
    • Medically important species: B. abortus (cattle), B. melitensis (goats/sheep), B. suis (pigs), B. canis (dogs).
    • Morphology: Gram-negative coccobacilli, non-motile, non-capsulated.
    • Cultivation: Requires nutrient-rich agar (e.g., serum, glycerin) with CO2 and aerobic to microaerophilic conditions.
    • Incubation periods: Days to weeks.
    • Colony characteristics: Fastidious, slow-growing; pinpoint, smooth; visible after 3–5 days incubation at 37°C. Non-hemolytic.
    • Virulence factors: LPS (intracellular multiplication in reticuloendothelial system and macrophages), toxic enzymes (catalase, superoxide dismutase).
    • Transmission: Primarily through contact with infected animals or consuming animal products; person-to-person is rare.
    • Diagnosis: Demonstration by fluorescent antibody, blood culture (not always positive), and serological tests (Rose Bengal test, STAT, ELISA).
    • Treatment: Tetracycline + Rifampin.
    • Complications: acute febrile illness; potentially affect any organ system; may persist as relapse, chronic localized infections, or delayed convalescence.

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Gram-Negative Coccobacilli Lecture Notes PDF

    Description

    Explore the characteristics and significance of Gram-negative coccobacilli, including key genera such as Haemophilus, Bordetella, and Brucella. This quiz covers their morphology, cultivation requirements, and virulence factors, as well as the specific features of Haemophilus influenzae.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser