What are the main features of Fluorescent Microscopy?

• are advanced microscopes that use a beam of electrons instead of light to achieve much higher magnification and resolution.

• Utilize an electron beam to illuminate the specimen, which allows for
imaging at the nanometer scale.

Main types are Transmission Electron Microscopes (TEM) for internal
structures and Scanning Electron Microscopes (SEM) for surface details.

Advantages: Extremely high resolution (up to atomic level); can visualize
structures far smaller than those visible with light microscopes.

• Limitations: Expensive, large, and complex; requires vacuum environment and extensive sample preparation, including dehydration and coating with conductive material.

What is a direct examination of organisms?

process of observing and identifying microorganisms or other biological specimens directly from clinical or environmental samples without
culturing them.

What is the method for directly examining an organism?

involves observing organisms directly under a
microscope. ( can be used to identify the type and quantity of bacteria, parasites, or fungi in a sample like blood, urine, or tissue)

What is the purpose of differential staining?

distinguishes between different types of cells or cell components.

(Gram stain and Acid-fast stain)

Gram stain, Giema stain, India ink

What is the purpose of Acid-Fast Staining?

Identifies acid-fast bacteria, which have waxy cell walls that resist decolorization by acids.

What is the staining process for Acid-Fast staining?

Staining:
• Primary Stain: Carbol fuchsin (penetrates waxy cell walls).
• Decolorizer: Acid-alcohol (removes stain from non-acid fast cells).
• Counterstain: Methylene blue (stains non-acid-fast cells
for contrast).

What is the purpose of fluorescent staining?

Uses fluorescent dyes to label and visualize specific
microorganisms or cellular components under a fluorescence
microscope.

Bacterial structure that activates the innate host response:

Lipopolysaccharides (LPS)

Antiphagocytic bacterial structure:

capsule is an antiphagocytic structure

Peptidoglycan in Gram-positive bacteria:

Gram-positive bacteria have a thick layer of
peptidoglycan in their cell wall, which provides rigidity and structural support. Purple.

Common biochemical pathway for pyruvate in bacteria without oxygen:

fermentation is the common pathway where pyruvate is converted to lactate

The structure that protects a colony from the environment, antimicrobials, and host response

Biofilm protects bacterial colonies from environmental stress

Virulence mechanisms attaching bacteria to the host

Adhesins (such as pili, fimbriae, and
surface proteins) allow bacteria to attach to host cells.

Virulence mechanisms when bacteria enter the host:

Invasion occurs when bacteria penetrate and spread through host tissues,

Bacterial products that harm tissue or destroy biological activities

Exotoxins and endotoxins are bacterial products

Mechanisms of antibiotic action interfering with the bacterial cell wall:

Beta-lactams (e.g.,penicillin) and glycopeptides (e.g., vancomycin) inhibit cell wall synthesis.

Mechanisms of antibiotic action stopping protein production:

Antibiotics like aminoglycosides and tetracyclines inhibit protein synthesis by targeting bacterial ribosomes.

Mechanisms of antibiotic action stopping genetic material production:

Fluoroquinolones inhibit DNA replication, and rifampin inhibits RNA synthesis

Mechanisms of antibiotic action stopping bacterial production of essential nutrients:

Sulfonamides and trimethoprim interfere with folic acid synthesis, which is crucial for bacterial DNA and RNA production

Bacteria acting in different tissues:

Staphylococcus aureus can infect various tissues and cause diseases ranging from skin infections to pneumonia and sepsis.

Bacteria needing to be internalized into the host to become activated:

Chlamydia trachomatis requires internalization into host cells to complete its lifecycle.

Bacteria that can’t be cultured on artificial media:

Treponema pallidum, the causative agent of syphilis, cannot be cultured on artificial media.

Bacteria with a specific shape recognizable under a microscope:

Vibrio cholerae has a characteristic comma shape, making it identifiable under a microscope.

Bacteria producing abortion and diphtheria:

Corynebacterium diphtheriae causes diphtheria, while Brucella species are associated with abortion in livestock.

Bacteria detected using horse blood agar:

Listeria monocytogenes is often detected on blood agar due to its hemolytic properties.

Bacteria with capsular polysaccharides:

Streptococcus pneumoniae and Haemophilus influenzae have capsular polysaccharides that enhance virulence.

Virulence factors associated with Enterobacteriaceae family:

They include endotoxins, capsules, and adhesins

Bacteria confirmed with TCBS agar:

Vibrio cholerae can be detected using Thiosulfate
Citrate Bile Salts Sucrose (TCBS) agar.

Most common opportunistic bacteria:

Pseudomonas aeruginosa is a common opportunistic
pathogen.

Bacteria producing Pertussis

Bordetella pertussis causes whooping cough (pertussis).

Bacteria producing Brucellosis:

Brucella species cause brucellosis

Bacteria producing Tularemia:

: Francisella tularensis is the causative agent of tularemia.

Bacteria producing Syphilis:

Treponema pallidum causes syphilis

Bacteria producing Botulism

Clostridium botulinum is responsible for botulism

Anaerobic bacteria part of probiotics but can cause diseases in certain conditions:

Lactobacillus is generally beneficial but can cause infections in rare cases like endocarditis.

Bacteria producing Lyme disease:

Borrelia burgdorferi causes Lyme disease

Bacteria lacking a cell wall:

Mycoplasma species lack a cell wall

Main property in isolated culture of Clostridium perfringens:

Gas production and double zone hemolysis are characteristic of Clostridium perfringens.

Why mycobacterial infections need to be treated with multiple drugs for 6 months or more:

Mycobacterium tuberculosis has a slow growth rate, thick cell wall, and can become dormant, requiring long treatment with multiple drugs to prevent resistance.

Virulence factors associated with Neisseriaceae family

Pili, outer membrane proteins, and IgA protease are common virulence factors

Most common virulence factors:

toxins, adhesins, invasion enzymes, capsules, and biofilm formation.

Bacteria causing gastritis:

Helicobacter pylori causes chronic gastritis and can lead to peptic
ulcers.

Obligate intracellular parasite:

Bacteria causing Rocky Mountain Spotted Fever:

Rickettsia rickettsii