Podcast Beta
Questions and Answers
How is sterilization in an autoclave achieved?
What is the purpose of an antibiogram?
How do bacteria primarily divide?
What is symbiosis?
Signup and view all the answers
From a clinical perspective, how are bacteria classified?
Signup and view all the answers
Which of the following is true for enveloped viruses?
Signup and view all the answers
Viruses are primarily classified into several large groups based on:
Signup and view all the answers
Viruses can be purified based on their size and density using:
Signup and view all the answers
The most commonly used method of indirect virus counting is:
Signup and view all the answers
For virus isolation, embryos of the following are most commonly used:
Signup and view all the answers
Adhesion of the influenza virus to the target cell surface is enabled by the presence of:
Signup and view all the answers
In an infected cell, viruses can do everything except:
Signup and view all the answers
The 'holes' formed in tissue culture due to virus replication are called:
Signup and view all the answers
Which statement is not true:
Signup and view all the answers
Conquistadors conquered the Aztec Empire with the help of an epidemic of:
Signup and view all the answers
Anthracis appears as:
Signup and view all the answers
Gram-positive lancet-shaped or flame-shaped diplococci suggest a diagnosis of:
Signup and view all the answers
Choose the correct sentence:
Signup and view all the answers
Swarming on agar is a cultural characteristic significant for the identification of:
Signup and view all the answers
Which of the following statements about typhoid fever is correct:
Signup and view all the answers
Cholera enterotoxin:
Signup and view all the answers
In a direct Gram stain preparation, how are meningococci and gonococci differentiated?
Signup and view all the answers
The causative agents of bacterial vaginosis include all bacteria except:
Signup and view all the answers
How long does M.tuberculosis form visible colonies on solid nutrient medium before a negative result is issued?
Signup and view all the answers
The exotoxin of Corynebacterium diphtheriae is:
Signup and view all the answers
Which exoproduct is considered a virulence factor of Staphylococcus aureus?
Signup and view all the answers
The presence of neutralizing antibodies to diphtheria toxin can be demonstrated by:
Signup and view all the answers
What type of bacterial species is Staphylococcus epidermidis?
Signup and view all the answers
Which selective medium is used for the isolation of Corynebacterium diphtheriae?
Signup and view all the answers
Where does E.coli most commonly cause pyogenic infections?
Signup and view all the answers
Which sentence is correct?
Signup and view all the answers
Does S.typhi reproduce in macrophages?
Signup and view all the answers
What is typhus?
Signup and view all the answers
Infections with S.Arizonae are common in which group?
Signup and view all the answers
Is cholera toxin an AB toxin that activates adenylate cyclase?
Signup and view all the answers
Which DNA viruses include Influenza A and hepatitis B virus?
Signup and view all the answers
What does not cause Gastroenteritis?
Signup and view all the answers
Which infection does not result in a chronic carrier state?
Signup and view all the answers
Which viruses are transmitted via respiratory transmission?
Signup and view all the answers
Which viruses have negative RNA?
Signup and view all the answers
What is true about Hepatitis C infection?
Signup and view all the answers
What is true about Measles virus?
Signup and view all the answers
Which of the following is NOT a viral zoonosis?
Signup and view all the answers
What is true about Hepatitis A?
Signup and view all the answers
What is true about Hepatitis B infection?
Signup and view all the answers
Which of these statements about Prions is true?
Signup and view all the answers
Which diseases are caused by 'slow viruses'?
Signup and view all the answers
What does Herpes simplex labialis NOT cause?
Signup and view all the answers
Which virus causes a vesicular rash?
Signup and view all the answers
What is true about Respiratory syncytial virus?
Signup and view all the answers
During the incubation period of HIV infection, what is NOT true?
Signup and view all the answers
Study Notes
Here are the study notes:
Virus Classification
- Viruses are primarily classified into several large groups based on: • Nucleic acid characteristics • Capsid symmetry • Type of host • Virus diameter
Virus Structure
- Viruses have: • A protein coat (capsid) • Genetic material (either DNA or RNA) • Sometimes, a lipid envelope (enveloped viruses)
- Enveloped viruses include: • Some icosahedral viruses • Some spherical viruses
Virus Replication
- Viruses can replicate: • In the host's cytoplasm • In the host's nucleus
- Viral RNA replicates in the host's: • Cytoplasm
- Intracellular structures formed by viral replication are: • Inclusion bodies
Bacterial Cell Structure
- The primary function of the capsule (as a bacterial cell envelope) is: • Protection of the bacterial cell
- Bacterial cell walls are composed of: • Peptidoglycan (in Gram-positive bacteria)
- The periplasmic space is located between: • The cell wall and the cytoplasmic membrane
- The cytoplasmic membrane is a: • Double-layer membrane
Bacteriology
- Bacteria are: • Prokaryotes
- Bacteria have: • A nucleoid (no true nucleus)
- The primary sterile region is: • The upper respiratory tract
Antimicrobial Agents
- Antimicrobial agents are substances that: • Kill or prevent the multiplication of microorganisms in a living organism
- Mechanisms of resistance include: • Enzymatic destruction or inactivation of the drug • Modification of the target enzyme • Alteration of cell wall permeability
Microbiology
- Sterilization is: • The method by which all living microorganisms are killed or removed
- Disinfection is: • The method by which the number of live microorganisms is reduced by killing or removing them
- The minimum inhibitory concentration is: • The minimum concentration sufficient to inhibit bacterial growth### Microbiology
- Bacteremia is a condition that occurs after the invasion of pathogenic microorganisms.
- Septicemia is the invasion of the blood by pathogenic microorganisms.
- Signs of inflammation include:
- Rubor (redness)
- Calor (heat)
- Tumor (swelling)
- Adherence occurs between receptors on the surface of microorganisms and target tissue.
- L-forms of bacteria:
- Are not found in nature
- Can occur in vitro conditions
- Are significant in antibiotic resistance
- Pathogenicity is the ability of bacteria to damage tissue and cause disease.
- Infectivity is the ability of a microorganism to establish an initial site of infection.
- Bacterial resistance to antibiotics:
- Exists
- Is a result of inadequate antibiotic use
- Invasiveness is the ability of a microorganism to establish an initial site of infection, proliferate, and spread.
Bacterial Structure and Function
- Peptidoglycan is a chemical compound present only in bacterial cells.
- Gram-positive and Gram-negative bacteria differ in terms of the composition of the cell wall.
- Not all bacteria have a cell wall (e.g., Mycoplasma).
- The cessation of growth in some bacteria leads to sporulation.
Toxins
- Endotoxins:
- Are lipopolysaccharides
- Are highly toxic
- Are found in the cell wall of bacteria
- Exotoxins:
- Are produced by bacteria
- Can cause disease
- Examples: diphtheria toxin, cholera toxin
Bacterial Diseases
- Typhoid fever:
- Is caused by Salmonella typhi
- Is transmitted through contaminated water and food
- Can be diagnosed with the Widal test
- Diphtheria:
- Is caused by Corynebacterium diphtheriae
- Is transmitted through respiratory droplets
- Can be diagnosed with the Elek test
- Tuberculosis:
- Is caused by Mycobacterium tuberculosis
- Is transmitted through respiratory droplets
- Can be diagnosed with the tuberculin test
- Cholera:
- Is caused by Vibrio cholerae
- Is transmitted through contaminated water and food
- Can be diagnosed with the cholera toxin test
- Anthrax:
- Is caused by Bacillus anthracis
- Is transmitted through contact with contaminated animals or their products
- Can be diagnosed with the culture of the bacterium
Virulence Factors
- Capsule:
- Is a polysaccharide structure
- Is a virulence factor
- Examples: Streptococcus pneumoniae, Haemophilus influenzae
- Pilus:
- Is a protein structure
- Is involved in adherence
- Examples: E. coli, Neisseria gonorrhoeae
- Endotoxin:
- Is a lipopolysaccharide structure
- Is a virulence factor
- Examples: Gram-negative bacteria
- Exotoxin:
- Is a protein structure
- Is a virulence factor
- Examples: diphtheria toxin, cholera toxin
Bacterial Classification
- Enterobacteriaceae:
- Includes E. coli, Salmonella, Shigella, Klebsiella
- Are Gram-negative
- Are commonly found in the gut
- Staphylococcaceae:
- Includes Staphylococcus aureus, Staphylococcus epidermidis
- Are Gram-positive
- Are commonly found on the skin
- Streptococcaceae:
- Includes Streptococcus pyogenes, Streptococcus pneumoniae
- Are Gram-positive
- Are commonly found in the respiratory tract
- Mycobacteriaceae:
- Includes Mycobacterium tuberculosis, Mycobacterium bovis
- Are Gram-positive
- Are commonly found in the respiratory tract
Bacterial Vaccines
- BCG vaccine:
- Is used to prevent tuberculosis
- Is composed of attenuated Mycobacterium bovis
- Is administered immediately after birth
- Diphtheria vaccine:
- Is used to prevent diphtheria
- Is composed of inactivated Corynebacterium diphtheriae
- Is administered in childhood
- Typhoid vaccine:
- Is used to prevent typhoid fever
- Is composed of inactivated Salmonella typhi
- Is administered in childhood
- Anthrax vaccine:
- Is used to prevent anthrax
- Is composed of inactivated Bacillus anthracis
- Is administered in high-risk individuals### Chlamydia
- Elementary bodies and reticulate bodies of chlamydia do not differ in RNA/DNA ratio, size, structure of the main protein of the cell membrane, or infectivity for the host cell.
- Chlamydiae are obligate intracellular parasites.
- They do not possess either DNA or RNA, but rather both nucleic acids together.
Mycoplasmas
- Mycoplasmas differ from other bacteria in that they do not have cell walls.
- They are part of the normal flora of the urogenital tract.
Tetanus
- Tetanus toxin causes spastic paralysis of skeletal muscles.
- Neonatal tetanus occurs if the mother is not properly protected against tetanus.
- A typical tetanus-prone wound is a puncture wound.
- Tetanus toxin is a neurotoxin.
Bacillus anthracis
- Bacillus anthracis is a sporogenic bacterium of spherical shape.
- It is a nonmotile bacterium.
- Neisser staining of Bacillus anthracis can reveal metachromatic granules.
- Anthrax can be transmitted through vectors, from domestic animals, or from wild animals.
Diphtheria
- Diphtheroids can cause sepsis.
- The vaccine against diphtheria is an anatoxin.
- The pathogenesis of diphtheria involves the production of exotoxin, which inhibits protein synthesis.
Intestinal Bacteria
- Virulence factors of intestinal bacteria include capsules, endotoxin (lipid A), and adhesins.
- The normal bacterial flora of the digestive tract includes E. coli, Enterobacter sp., and Proteus sp.
- The normal bacterial flora of the urogenital tract includes E. coli, Enterobacter sp., and Proteus sp.
Botulism
- Botulism is caused by Clostridium botulinum.
- Prevention of botulism is carried out by thermal processing of food and administration of hyperimmune gamma globulin.
- Clostridium botulinum produces a powerful neurotoxin.
Pneumococcal Capsule
- The pneumococcal capsule contributes to virulence by reducing the efficiency of phagocytosis.
Meningococci
- Meningococcal carriage refers to the presence of N. meningitidis on the mucous membrane of the nasopharynx.
- Meningococci and gonococci can be differentiated in a direct Gram stain preparation.
Mycobacteria
- Mycobacteria are acid-alcohol resistant and have a slow growth rate.
- They are stained with special staining using Ziehl-Neelsen stain.
- Mycobacteria are cultured on Lowenstein-Jensen medium.
- Tuberculin-positive individuals are resistant to tuberculosis infection.
Helicobacter pylori
- Helicobacter pylori plays a role in the development of gastritis and duodenal ulcers.
- It is a common cause of diarrhea.
Rickettsiae
- Rickettsiae are Gram-negative bacteria.
- They are transmitted through vectors, such as ticks, mites, or human body lice.
Epidemic Typhus
- Epidemic typhus is transmitted through human body lice.
- Rickettsiae are the causative agents of epidemic typhus.
Botulinum Toxin
- Botulinum toxin is a neurotoxin that inhibits the release of acetylcholine.
Erysipelothrix rhusiopathiae
- Erysipelothrix rhusiopathiae is transmitted to humans from domestic animals.
Coagulase
- Coagulase is a virulence factor of Staphylococcus aureus.
Penicillinase
- Penicillinase is a virulence factor of Staphylococcus aureus.
Enterotoxin
- Enterotoxin is a virulence factor of Staphylococcus aureus.
Collagenase
- Collagenase is a virulence factor of Clostridium perfringens.
Streptococci
- Streptococci are catalase-negative cocci.
- Group B streptococci (Streptococcus agalactiae) have a polysaccharide antigen in the cell wall that antigenically differs from the polysaccharide of group A beta-hemolytic streptococci (Streptococcus pyogenes).
Salmonellae
- Salmonellae are divided into more than 2000 serotypes based on group O and type H antigens.
- Gastroenteritis caused by salmonellae is transmitted by contaminated food, water, or infected animal products.
Shigellae
- Shigellae move through enterocytes using a "comet tail" mechanism.
- Shigellae cause bacillary dysentery.
- The infectious dose of Shigellae is less than 200 bacteria.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Multiple choice questions about viruses, their classification, and purification methods. Covers topics such as enveloped viruses, capsid symmetry, and nucleic acid characteristics.