Microbiology of Vibrio and Related Bacteria

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Questions and Answers

What type of colonies do Vibrio species produce on TCBS agar?

Blue or green colonies

Yellow or green colonies (correct)

Clear colonies

Red or white colonies

Which organism does not require salt for growth?

Vibrio parahaemolyticus

Chromobacterium violaceum

Vibrio harveyi

Vibrio cholerae (correct)

What is the primary mode of transmission for cholera?

Fecal-oral route (correct)

Vector-borne transmission

Direct contact transmission

Airborne transmission

What is used for enrichment broth to obtain growth of vibrios from stool samples?

Alkaline peptone water Signup and view all the answers

In addition to the fecal-oral route, what other method can lead to cholera infections?

Ingestion of contaminated water Signup and view all the answers

Which method is directly used for observing pathogens under a microscope?

Gram stain Signup and view all the answers

What is the primary purpose of using sheep blood agar in cultivation?

To exhibit hemolysis Signup and view all the answers

What factor combination is essential for growing certain bacteria using culture media?

Both X and V factors Signup and view all the answers

Which pathogen is known to be an uncommon cause of endocarditis?

H. aphrophilus Signup and view all the answers

What is the recommended swabbing technique for collecting samples?

Swab in selective medium within 10 minutes Signup and view all the answers

Which media provides both hemin and NAD necessary for certain bacterial growth?

Chocolate Agar Signup and view all the answers

What is centrifugation generally used for in the detection methods?

Concentration of bacterial cells Signup and view all the answers

The term 'satelliting' in blood agar refers to which phenomenon?

Dependency on V factor for growth Signup and view all the answers

What is the primary habitat of Helicobacter pylori?

Human gastric mucosa Signup and view all the answers

Which of the following is NOT a possible route of transmission for Helicobacter pylori?

Airborne droplets Signup and view all the answers

What is one of the main modes of transmission for infections caused by Pasteurella multocida?

Animal bites or scratches Signup and view all the answers

Which of the following best describes the role of the capsule in Pasteurella multocida?

It protects against immune attack Signup and view all the answers

What structure is associated with the adhesion of Bordetella pertussis?

Fimbriae Signup and view all the answers

Which organ system is NOT mentioned as being infected by Pasteurella multocida?

Nervous system Signup and view all the answers

Which toxin produced by Bordetella pertussis is related to the cholera toxin?

Pertussis toxin Signup and view all the answers

What complication can arise from bacteremia associated with Pasteurella multocida infections?

Metastatic abscess formation Signup and view all the answers

What is the function of the Tracheal colonization factor in Bordetella pertussis?

Facilitate attachment to respiratory epithelium Signup and view all the answers

What characterizes the habitat of Pasteurella multocida?

Normal flora of wild and domestic animals Signup and view all the answers

Which of the following factors allows Helicobacter pylori to move within the stomach?

Flagella Signup and view all the answers

Which procedure is specifically noted for its special consideration in the laboratory diagnosis of Pasteurella infections?

Gram stain analysis Signup and view all the answers

What is the role of adenylate cyclase toxin produced by Bordetella pertussis?

Hemolyzes red cells and activates cyclic AMP Signup and view all the answers

What is the significance of the dermonecrotic toxin in Bordetella pertussis?

Causes tissue damage Signup and view all the answers

Which of the following is NOT a risk factor for Pasteurella multocida infections?

Contaminated food handling Signup and view all the answers

What type of bacteria is Pasteurella multocida classified as?

Gram-negative bacilli Signup and view all the answers

What method is commonly used for the direct detection of B. pertussis in smears from nasopharyngeal material?

One step immunochromatographic assay Signup and view all the answers

Which of the following is not a method for identifying Bordetella pertussis?

Inoculation in nutrient broth Signup and view all the answers

What type of vaccines are used for the prevention of pertussis?

Whole cell vaccines and acellular vaccines Signup and view all the answers

Which organism is part of the Mycobacterium tuberculosis complex?

Mycobacterium bovis Signup and view all the answers

Which characteristic do anaerobic bacteria possess?

They will not grow in the presence of oxygen Signup and view all the answers

Which of the following is a type of Nontuberculous Mycobacterium?

All of the above Signup and view all the answers

What is a key characteristic of organisms belonging to the genus Mycobacterium?

They cannot be cultured under aerobic conditions Signup and view all the answers

What is the primary virulence factor associated with Bordetella pertussis?

Adenylate cyclase toxin Signup and view all the answers

What type of organism is responsible for tetanus?

Clostridium tetani Signup and view all the answers

What primarily causes botulism?

Ingestion of preformed toxin Signup and view all the answers

Which of the following correctly describes the effects of tetanospasmin?

It causes generalized muscle spasms. Signup and view all the answers

What is a common size range for aerosols produced in certain infections?

1 to 5 μm Signup and view all the answers

What is a significant consequence of untreated muscle spasms caused by tetanospasmin?

Respiratory failure Signup and view all the answers

What type of environment can contribute to botulism toxin absorption?

Nonacidic vegetable or mushroom foodstuffs Signup and view all the answers

What can trigger spasms in individuals affected by tetanus?

A mild touch or minor stimuli Signup and view all the answers

Which maneuver can also produce infectious aerosols in a laboratory?

Manipulations of lesions Signup and view all the answers

Study Notes

Vibrio, Plesiomonas, and Chromobacterium

These microorganisms are often found in contaminated water, food, and soil.
Vibrio cholerae: Transmission is fecal-oral route, contaminated water/food. Has two key toxins: Cholera toxin and Somatic O antigen. Key test is to distinguish from other halophilic Vibrio species using NaCl and string tests.
Vibrio parahaemolyticus: Transmitted through ingestion of contaminated raw or undercooked seafood.
Aeromonas spp.: Transmission via raw or undercooked contaminated seafood and water.
Plesiomonas shigelloides: Ingestion of contaminated seafood and/or water.
Chromobacterium violaceum: Exposure to contaminated soil or water.

Pathogenesis and Spectrum of Disease

Vibrio cholerae: Causes diarrheal illness, characterized by rice-watery stools.
Types of infections depend on the specific species and can include gastroenteritis, wound infections, and bacteremia.
Laboratory Diagnosis: ELISA and latex agglutination tests are used to detect specific antigens or antibodies.
Other organisms: Have various modes of transmission and produce different types of toxins.

Pasteurella and Similar Organisms

General characteristics: Small, gram-negative bacilli, nonmotile, oxidase positive, ferment glucose.
Habitat and Transmission: Associated with the nasopharynx and gastrointestinal tracts of wild and domestic animals. Transmission mainly by bites or scratches from animals.
Virulence factors: Some types have endotoxin (contributing to inflammation) and/or antiphagocytic capsules.
Laboratory Diagnosis: Special considerations are needed for proper specimen collection for testing.

Haemophilus

Habitat and transmission: Found as part of the normal flora of the respiratory tract in humans. Transmission is likely via respiratory droplets.
Pathogenesis and Spectrum of Disease (H. influenzae): Causes various infections, such as meningitis, epiglottitis, and pneumonia in different biogroups.
Pathogenesis and Spectrum of Disease (H. ducreyi): Causes chancroid, a sexually transmitted disease (STD), characterized by painful genital ulcers.
Laboratory Diagnosis: Special considerations for specimens, due to the fastidious nature of the bacteria and the need for specific growth factors.

Campylobacter, Arcobacter, and Helicobacter

Helicobacter pylori: Found in the human stomach. Mode of transmission is unknown; possible routes are oral-oral and fecal-oral.
Virulence factors: Includes CagA protein, adhesin, inflammation mediators, and cytotoxin.
Conditions caused: Gastritis and peptic ulcer disease.
Laboratory Diagnosis: Tissue biopsy is a useful diagnostic method.
Other organisms: Have different pathogenic mechanisms and clinical presentations.

Anaerobic Bacteria

General Characteristics: Cannot grow in the presence of oxygen.
Specific examples: Clostridium perfringens, Clostridium tetani, Clostridium botulinum, and Clostridium difficile.
Associated diseases: Gas gangrene (C. perfringens), Tetanus (C. tetani), Botulism (C. botulinum), and antibiotic-associated diarrhea (C. difficile).

Mycobacteria

General Characteristics: Slow-growing, aerobic bacteria.
Spectrum of Disease: Mycobacterium tuberculosis complex causes tuberculosis.
Mycobacteria tuberculosis complex: Infections occur via airborne droplet nuclei.
Other Mycobacteria: Have different diseases and transmission pathways.

Spirochetes

General characteristics: Long, slender, helically curved, Gram-negative bacteria with axial fibrils.
Specific examples: Treponema pallidum, Borrelia burgdorferi, and Leptospira interrogans.
Spectrum of disease (Treponema pallidum): Syphilis
Other organisms: Have different disease conditions and transmission pathways.

Obligate Intracellular Bacteria

Chlamydia trachomatis: Associated with several infections.
Laboratory Diagnosis: Uses special techniques to detect the organism.

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Description

Explore the fascinating world of Vibrio, Plesiomonas, and Chromobacterium. This quiz covers their transmission routes, diseases caused, and laboratory diagnosis methods. Test your knowledge on these important pathogens commonly associated with contaminated water and food.