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1
Q

What is the main function of the bacterial cell wall?

A

Provides overall strength, maintains cell shape, prevents osmotic lysis, and is involved in pathogenicity

Main component is peptidoglycan, thick in Gram-positive and thin in Gram-negative bacteria.

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2
Q

What are the two forms of glycocalyx?

A
  • Capsule
  • Slime layer

Capsule is firmly attached and highly organized, while slime layer is loosely attached.

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3
Q

What is the function of the capsule in bacteria?

A

Enhances virulence by preventing phagocytosis

It protects the cell from desiccation and aids adherence.

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4
Q

What is the composition of the slime layer?

A

Mainly polysaccharides, glycoproteins, and glycolipids

It is loosely attached and easily washed off.

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5
Q

What are the main components of flagella?

A
  • Filament
  • Hook
  • Basal body

Flagella are important for motility via taxis.

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6
Q

What is the shape of cocci bacteria?

A

Spherical / round shape

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7
Q

What is the purpose of Gram staining?

A

To differentiate between Gram-positive and Gram-negative bacteria based on cell wall composition

Gram-positive appear purple, while Gram-negative appear pink.

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8
Q

What type of stain is used for Mycobacterium tuberculosis?

A

Acid-Fast stain

It shows apple green fluorescence due to mycolic acid in the cell wall.

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9
Q

What are the types of bacteria based on oxygen requirement?

A
  • Obligate aerobe
  • Obligate anaerobe
  • Facultative anaerobe
  • Microaerophile
  • Aerotolerant

Each type has different oxygen usage characteristics.

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10
Q

What temperature range do psychrophiles thrive in?

A

< 20°C

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11
Q

What is the function of endospores?

A

To survive harsh conditions

They are very resistant to heat, radiation, and chemicals.

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12
Q

What is the function of fimbriae?

A

Important for adhesion of cells and biofilm formation

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13
Q

What are the phases of the bacterial growth curve?

A
  • Lag Phase
  • Log (Exponential) Phase
  • Stationary Phase
  • Death Phase

Each phase has distinct characteristics in bacterial growth and response to antibiotics.

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14
Q

What type of media supports the growth of non-fastidious bacteria?

A

Basal Media

It contains basic nutrients without added enrichments.

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15
Q

What is a characteristic of selective media?

A

Encourages the growth of specific bacteria while inhibiting others

Examples include MacConkey agar for Gram-negative bacteria.

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16
Q

What is a plasmid?

A

A small, circular DNA molecule found in bacteria that can replicate independently

Plasmids are often involved in antibiotic resistance and gene transfer.

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17
Q

What are transposons?

A

Small DNA fragments that can move within the genome

They can cause gene mutations and contribute to antibiotic resistance.

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18
Q

What are genomic islands?

A

Horizontally transferred gene clusters in bacterial genomes that provide adaptive traits

They can include pathogenicity islands, resistance islands, and metabolic islands.

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19
Q

What is conjugation in bacteria?

A

The mating of two bacterial cells during which DNA is transferred from donor to recipient

This process is controlled by F-plasmid.

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20
Q

What is the difference between mutational and transferable drug resistance?

A

Mutational is chromosomal and non-transferable, while transferable is plasmid-mediated and can spread to other bacteria

Transferable resistance often involves multiple drugs.

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21
Q

What is colonization in bacterial pathogenesis?

A

Bacteria establish and multiply at a site without causing tissue damage or symptoms

Example includes E. coli in the gut.

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22
Q

What are virulence factors?

A

Traits that enable bacteria to cause disease

These include adherence, invasion, toxin production, and evasion of the immune system.

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23
Q

What is the mode of transmission for direct bacterial spread?

A

Touch, droplets transmission, contact with soil, skin puncture, placenta

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24
Q

What are the key features that allow bacterial pathogens to cause disease?

A

Bacterial pathogens must be transmissible, adhere to host tissues, invade cells or tissues, produce toxins, and evade the host immune system.

These traits are referred to as virulence factors.

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25
What are the modes of transmission for bacterial pathogens?
Modes of transmission include: * Direct (touch, droplets, soil contact, skin puncture, placenta) * Indirect (vehicles borne, vectors borne, air borne, fomites)
26
What are the common routes of entry for bacteria into the host?
Routes of entry include: * Respiratory Tract * Gastrointestinal Tract * Genitourinary Tract * Skin or Mucosa Breaches
27
Define tissue specificity in the context of bacterial infection.
Tissue specificity refers to the immunological identity of antigens in the tissues, influencing which bacteria can grow in specific tissues.
28
What is tissue tropism?
Tissue tropism is the range of host cells that support the growth of specific pathogens.
29
What is biofilm formation and its significance in bacterial infections?
Biofilm formation is the creation of protective slimy layers by bacteria on tissue surfaces, helping them resist antibiotics and immune responses.
30
What are the two types of damage that bacteria can cause to the host?
Bacteria can cause: * Direct Damage (invasion and tissue destruction) * Indirect Damage (overstimulation of the immune system leading to inflammation and tissue injury)
31
What are exotoxins and their effects?
Exotoxins are proteins produced by bacteria that can cause toxicity, affecting various systems such as the gastrointestinal tract, nervous system, and general cellular function.
32
What are endotoxins and their associated effects?
Endotoxins are lipopolysaccharides found in the cell wall of Gram-negative bacteria, leading to symptoms such as fever and organ failure when released.
33
How do bacteria evade host immunity?
Bacteria evade host immunity by: * Blocking phagocytosis * Surviving inside phagocytes
34
What is the definition of normal flora?
Normal flora are microorganisms, mostly bacteria, that inhabit the human body without causing disease in healthy individuals.
35
What are the two types of normal flora?
The two types of normal flora are: * Resident Flora * Transient Flora
36
What factors influence the composition of normal flora?
Factors influencing normal flora include: * Age * Immune Status * Local Environment * Diet
37
What benefits do normal flora provide?
Benefits include: * Synthesis of Vitamin B and K * Regulation of immunity * Prevention of pathogenic microbial proliferation * Production of bacteriocins * Assistance in nutrient breakdown
38
What harmful effects can normal flora have?
Harmful effects include: * Opportunistic infections in immunocompromised individuals * Antibiotic resistance and overgrowth of harmful flora * Conversion of substances into carcinogenic compounds
39
What is selective toxicity in antimicrobial drugs?
Selective toxicity refers to the ability of a drug to damage an infecting microorganism without harming the host.
40
What is the difference between bactericidal and bacteriostatic drugs?
Bactericidal drugs kill bacteria directly, while bacteriostatic drugs inhibit bacterial growth and reproduction.
41
What is the Minimum Inhibitory Concentration (MIC)?
The MIC is the lowest antimicrobial concentration that prevents visible growth of an organism after 24 hours of incubation.
42
What is the Minimum Bactericidal Concentration (MBC)?
The MBC is the lowest antimicrobial concentration that can kill 99.9% of the initial bacterial population.
43
What are the methods to measure antibiotic sensitivity?
Methods include: * Disc Diffusion * Dilution Tests * Epsilometer Test (E-test) * Automated Antibiotic Sensitivity Test
44
What are narrow-spectrum antibiotics?
Narrow-spectrum antibiotics act on a single or limited group of microorganisms.
45
What is the global problem of antimicrobial resistance (AMR)?
AMR complicates treatment, increases mortality and morbidity, requires longer hospital stays, and limits treatment options.
46
What are some measures to reduce drug resistance?
Measures include: * Prevention via vaccines and hygiene * Optimized antibiotic use through accurate diagnostics and rational prescribing
47
What does MRSA stand for?
Methicillin Resistant Staphylococcus aureus
48
What does VRSA stand for?
Vancomycin Resistant Staphylococcus aureus
49
What does MDR-TB stand for?
Multi Drug-Resistant Tuberculosis
50
Fill in the blank: The _______ is the lowest antimicrobial concentration that can kill 99.9% of the initial bacterial population.
MBC
51
True or False: Bacteriostatic drugs kill bacteria directly.
False
52
What does ESBL stand for?
Extended-Spectrum Beta-Lactamase
53
What does MBL stand for?
Metallo-β-lactamase
54
What is a key measure to reduce drug resistance?
Prevention
55
Name one method of prevention to reduce drug resistance.
Vaccines
56
How can hygiene contribute to reducing drug resistance?
Hand washing and infection control can prevent bacteria spread
57
What is meant by 'optimized antibiotic use'?
Using accurate diagnostics, rational prescribing, stewardship programs, and shorter treatment courses
58
What is the role of stewardship programs?
Promote wise antibiotic use
59
What is the purpose of research in developing new therapies?
To research new antibiotics and combination therapy to prevent resistance development
60
What does environmental monitoring involve?
Monitoring antibiotic use and resistance in water, soil, etc.
61
Why is education and training important in the context of drug resistance?
To teach public and patients about correct antibiotic use and train healthcare workers on AMR best practices
62
What are the general properties of viruses?
Non-living, acellular particles that infect all forms of life
63
What is the basic unit of a virus?
Virion
64
What are the two types of nucleic acids that viruses can contain?
DNA or RNA
65
What is the first virus isolated?
Tobacco Mosaic Virus (TMV)
66
What are the three classifications of viruses based on shape?
* Helical Viruses * Polyhedral Viruses * Complex Viruses
67
What characterizes non-enveloped viruses?
They only have a capsid and are more resistant to heat
68
What is the difference between DNA and RNA viruses in terms of genome size and mutation rate?
DNA viruses have larger genomes and lower mutation rates; RNA viruses have smaller genomes and higher mutation rates
69
What is the purpose of laboratory diagnosis of viruses?
To confirm disease cause, guide antiviral treatment, monitor outbreaks, and detect new virus variants
70
What is the method of direct detection of viruses?
Microscopic examination and antigen detection
71
What is the role of nucleic acid testing in virus diagnosis?
To detect virus DNA or RNA using PCR
72
What happens during the adsorption phase of viral replication?
Viral surface proteins bind to specific host cell receptors
73
What is the process by which enveloped viruses enter host cells?
Direct fusion or viropexis
74
What is a key component of the viral structure that protects genetic material?
Capsid
75
What occurs during the synthesis of viral components?
Transcription and genome replication
76
What are the two main types of infections caused by viruses?
* Lytic infection * Persistent infection
77
What is viral tropism?
The virus's ability to infect specific cells or tissues
78
What is the function of interferon in the host immune response?
To provide the first line of defense against viral infections
79
Fill in the blank: Many infections are _______.
asymptomatic
80
What can cause virus-induced immunopathology?
Immune responses that kill infected or healthy cells
81
What is the outcome of infected cells in abortive infections?
No virus produced, but the cell may die
82
What type of viruses can be oncogenic?
Persistent viruses
83
What is the incubation period in viral pathogenesis?
The time between infection and the appearance of symptoms

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