Categories of microorganisms:

1. Bacteria

2. Archaeans

3. Algae

4. Protozoa

5. Fungi

7. Helminths

Categories of microorganisms, Which are Prokaryotes?

1. Bacteria

2. Archaeans

3. Algae

4. Protozoa

5. Fungi

7. Helminths

Categories of microorganisms, Which are Eukaryotes?

1. Bacteria

2. Archaeans

3. Algae

4. Protozoa

5. Fungi

7. Helminths

Germ Theory of Disease, Which are correct?

1. Bacteria must be present in every case of the disease.

2. Bacteria must be isolated from the host with the disease and grown in pure culture.

3. Specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.

4. Bacteria must be recoverable from the experimentally infected host.

Nucleus:

Lack a true nucleus, one circular chromosome, not membrane bound

Nucleus:

Paired chromosomes, in nuclear membrane

Membrane-bound organelles:

Absent

Membrane-bound organelles:

ER, Golgi complex, Lysosome, Mitochondrion, Chloroplast, Peroxisome

Flagella:

Two protein building blocks

Flagella:

Complex, multiple microtubules

Glycocalyx:

Present as a capsule or slime layer

Glycocalyx:

Present in some cells that lack a cell wall

Cell wall:

Peptidoglycan cell walls

Cell wall:

Polysaccharide cell walls

Plasma membrane:

No carbohydrates and generally lacks sterols

Plasma membrane:

Sterols and carbohydrates that serve as receptors present

Cytoplasm:

No cytoskeleton or cytoplasmic streaming

Cytoplasm:

Cytoskeleton or cytoplasmic streaming

Cell division:

Binary fission

Cell division:

Mitosis

Size, shape, and arrangement:

Rod

Size, shape, and arrangement:

Spherical

Size, shape, and arrangement:

Vibrio, Spirillum, Spirochete

Bacterial cell wall, Which contain these?

1. Thick layer of peptidoglycan

2. Cell membrane

3. Tightly bound acidic polysaccharides, including teichoic acid and lipoteichoic acid

4. Retain crystal violet and stain purple

Bacterial cell wall, Which contain these?

1. Thin peptidoglycan

2. Inner membrane

3. An outer membrane containing lipopolysaccharide. Lipid A of LPS acts as endotoxin

4. Periplasmic space

5. Lose crystal violet and stain red from safranin counterstain

Gram stain:

Enterococcus spp.

Gram stain:

Staphylococcus supp.

Gram stain:

Streptococcus supp.

Gram stain:

Neisseria (e.g. N.gonorrhoeae)

Gram stain:

Clostridium (C. botulinum)

Gram stain:

Bacillus (B. anthracis)

Gram stain:

Corynebacterium (C. diptheriae)

Gram stain:

Enterobacteriaceae (e.g. Enterobacter, Escherichia, Klebsiella, Proteus, Salmonella, Shigella spp.)

Gram stain:

Pseudomonas

Gram stain:

Listeria

Gram stain:

Vibrio cholerae

Gram stain:

Treponema pallidum

Gram stain:

Borrelia burgdorferi

Gram stain:

Helicobacter pylori

Naturally lack a cell wall

Major Fungal Infections of Humans:

Epidermis, hair and dermis

Name of infection?

Major Fungal Infections of Humans:

Mucous membrane, skin, nails

Name of infection?

Protozoa, Two stage life cycle:

Stages that actively feed and multiply

Protozoa, Two stage life cycle:

1. Stages with a protective membrane or thickened wall

2. Dormant resting stage when conditions in the environment become unfavorable

Which are platyhelminthes?

1. Trematoda

2. Cestoda

3. Nematodes

Platyhelminthes:

Small flat leaf-like bodies with oral and ventral suckers and blind sac-like gut

Platyhelminthes:

Long flat ribbon-like bodies with a single anterior holdfast organ (scolex) and numerous segments (proglottides)

Platyhelminthes:

Which have a body cavity?

1. Trematoda

2. Cestoda

3. Nematodes

Viruses replication:

Binding of virus to specific molecule on host cell

Viruses replication:

The virion is endocytosed and contained within a cytoplasmic vacuole

Viruses replication:

The viral nucleic acid is released from the capsid

Viruses replication:

Viral components are produced

Viruses replication:

New viral particles are constructed

Viruses replication:

Assembled viruses are released by budding (exocytosis) or cell lysis

Viruse with segmented genome:

What is discribed as

1. Small changes in the genes

2. These changes can accumulate over time and result in viruses that are antigenically different

3. Repeated epidemics observed with influenza A or B virus

Viruse with segmented genome:

What is discribed as

1. Influenza viruses have segmented genome

2. Genetic reassortment occur when two influenza viruses infect the same cell

3. major, sudden change in genetic makeup of the virus

Viral identification:

use antibodies to identify viruses

Viral identification:

Polymerase chain reaction (PCR): amlification of a selected DNA sequence

Factors that affect microbial growth, Oxygen:

require oxygen for growth

Factors that affect microbial growth, Oxygen:

only anaerobic growth (avoid oxygen)

Factors that affect microbial growth, Oxygen:

both aerobic and anaerobic growth; greater growth in presence of oxygen

Factors that affect microbial growth, Oxygen:

only anaerobic growth, but continues in presence of oxygen

Moist heat:

steam under pressure

Moist heat:

normal autoclave conditions: ?

Features of Antimicrobial Drugs:

Drug kills pathogens without damaging the host

Features of Antimicrobial Drugs:

Ratio between toxic dose and therapeutic dose / or ratio of TD50 to ED50

If therapeutic index high

If therapeutic index low

Inhibits bacteria fromreproducing, but doesn't otherwise kill them

Actively kills bacteria

Activity Spectrum:

Active against one or very few types

Activity Spectrum:

Active against several types of microorganisms

1. Initial antibiotic regimen

2. Use broad-spectrum antimicrobial agents to cover multiple possible pathogens commonly associated with the specific clinical syndrome

1. After identification of the etiologic pathogen and/or antimicrobial susceptbility data are available

2. Narrow the antibiotic spectrum

1. Beneficial

2. Inhibit growth of pathogens by occupying space, depleting nutrients and secreting materials

Do not usually cause problems, but have potential to cause infection

Pasteur's Swan Neck Flask Experiment

Germ Theory of Disease

Pasteur's Swan Neck Flask Experiment

Germ Theory of Disease

Methods in bacterial identification:

Growth at different temperatures, pH values, salt concentration, or atomospheric conditions or in the presence of various enzymes etc.

Methods in bacterial identification:

Identify and determine chemical components within a microorganism

Methods in bacterial identification:

Comparing + contrasting antigenic components of the microbial cell, involves reactions of microorganisms with specific antibodies: Combine known anti-serum with unknown bacterium

Endospores:

endospore formation

Endospores:

Return to vegetative state

1. Acid fast

2. Mycobacterium tuberculosis causes tuberculosis

3. Mycobacterium leprae causes leprosy (Hansen's disease)

Unique bacteria:

With nontypical cell walls

1. Mycobacterium

2. Nocardia

3. Mycoplasma

4. Rickettsia

5. Chlamydia

Unique bacteria:

Obligate intracellular parasites

1. Mycobacterium

2. Nocardia

3. Mycoplasma

4. Rickettsia

5. Chlamydia

Protozoan pathogens and human disease:

Amebic dysentery caused by Entamoeba histolytica

Protozoan pathogens and human disease:

Amoeboid protozoa:

Amebic dysentery caused by?

Protozoan pathogens and human disease:

Flagellated protozoa:

Giardiasis caused by?

Protozoan pathogens and human disease:

Flagellated protozoa:

African sleeping sickness (also known as African trypanosomiasis) caused by?

Protozoan pathogens and human disease:

Apicomplexan protozoa:

Malaria caused by?

Protozoan pathogens and human disease:

1. Giardiasis caused by Giardia lamblia

2. African sleeping sickness (also known as African trypanosomiasis) caused by Trypanosoma brucei

Protozoan pathogens and human disease:

Malaria caused by Plasmodium falciparum, P. malariae, P. ovale and P. vivax

Fungi:

mushrooms

Fungi:

molds, yeasts

Fungi, two morphologies:

round ovoid shape, asexual reproduction

Fungi, two morphologies:

long filamentous fungi or molds

Fungi:

Acquire nutrients from a wide variety of organic substrates

Fungi:

Grow on the bodies of living animals or plants, although very few require a living host

Structure of Viruses, two basic components:

single-or double-stranded RNA or DNA

Structure of Viruses, two basic components:

protein coat that surrounds and protects the viral genome

Virus with segmented genome:

1. Four types of influenza viruses: A, B, C and D

2. Influenza type A viruses are subtyps based upon the hemagglutinin (HA) and neuraminidase (NA) antigens, which are surface proteins found on the viral envelope

This is a DNA or a RNA virus?

Oncogenic Viruses:

Papilloma virus (HPV) -> ?

Oncogenic Viruses:

Epstein-Barr virus -> ?

Oncogenic Viruses:

Human herpesvirus (HV8) -> ?

Oncogenic Viruses:

Hepatitis B virus (HBV) and hepatitis C virus (HCV) -> ?

Factors affecting the efficacy of disinfection and sterilization, from most resistant to least:

1. Viruses with lipid envelopes

2. Prions

3. Endospores of bacteria

4. Gram-positive bacteria

5. Mycobacteria

6. Viruses without envelopes

7. Cysts of protozoa

8. Vegetative protozoa

9. Fungi, including most fungal spores

10. Gram-negative bacteria

Factors affecting the efficacy of disinfection and sterilization:

1. Duration of exposure

2. Concentration and potency of disinfectants

3. Microbes: Number, location, innate resistance, biofilms

4. Presence of solvents, organic matter, or inhibitors

5. Physical and chemical factors: temperature and pH of environment

Methods of chemical control:

1. Commonly found in household cleaners, mouthwashes, and hospital disinfectants

2. Act by denturing proteins and disrupting membranes

Methods of chemical control:

1. Include ethyl alcohol and isopropyl alcohol (Usual concentration: 70% (50% to 95%)

2. Antiseptics

3. Act by denaturing proteins and disrupting membranes

Methods of chemical control:

1. E.g. Chlorhexidine

2. Act by disrupting cell membranes

Antibiotic Sensitivity Testing:

Lowest cencentration of drug that inhibit the visible growth of bacteria

Antibiotic Sensitivity Testing:

Inhibits at least 99.9% of the bacterial colonies

Antibiotic Sensitivity Testing:

Can use

Antibiotic Sensitivity Testing:

Cannot use

Antibiotic Sensitivity Testing:

for allergy

The action of antimicrobial drugs:

1. Inhibition of cell wall synthesis

2. Inhibition of nucleic acid replication and transcription

3. Inhibition of synthesis of essential metabolites

4. Inhibition of protein synthesis

5. Injury to plasma membrane

Artificial intelligence in microbiology:

Algorithms that learn from data to improve predictions

Artificial intelligence in microbiology:

Advanced neural networks for analyzing complex datasets

Artificial intelligence in microbiology:

Quick analysis of genetic sequences, microbiological phenotypes, and clinical metadata

The impact of artifical intelligence on microbial diagnosis:

Which are the benefits of AI?

1. Rapid detection

2. Improved treatment strategies

3. Pattern recognition

1. Can be transmitted

2. Infection + Disease

1. Symptoms: a change in body function that is felt by a patient

2. Sign: a change in a body that can be measured or observed

3. Occurs when cells or molecules cannot function properly

The invasion and replication of microorganisms in or on the body that are not normally present within the body

Which are the outcomes of an infection?

1. Parasite overcomes the immune defenses -> cause disease

2. Immune defenses overcome the ability of the potential pathogen to cause the disease

3. Parasite (or potential pathogen) and the host survive together

Virulence:

Type and severity of infection depend on?

1. Pathogenicity

2. Condition of the host

3. Establish itself in a host

4. Cause damage

Virulence:

Virulence (the extent of pathogenicity) of a microbe is determined by its ability to?

1. Pathogenicity

2. Condition of the host

3. Establish itself in a host

4. Cause damage

Exoenzyme:

Coagulates fibrinogen (prevent bacterium from phagocytosis)

Exoenzyme:

Hydrolyzes collagen

Exoenzyme:

Disrupt the membrane of red blood cells

Exoenzyme:

Digest fibrin clots

Exoenzyme:

Destory mucopolysaccharides that holds cell together

Exoenzyme:

Destory IgA antibodies

Chain of Infection:

Bacteria, virus, fungi, parasite

Chain of Infection:

Human, water, air, medical equipment

Chain of Infection:

Secretion, excretion, droplets

Chain of Infection:

Contact, in air, by vector

Chain of Infection:

Mucosa lining, open wound, respiratory tract, etc.

Chain of Infection:

Immunocompromised, elderly people, post-operative individual, etc.

Chain of infection:

1. Microorganisms

2. Susceptible host

3. Port of entry

4. Reservoir

5. Port of exit

6. Means of transport

Epidemiology Terminology:

Disease that occurs occasionally in a population

Epidemiology Terminology:

Disease constantly present in a population

Epidemiology Terminology:

Disease occurrence exceed the normal expectancy in a given area in a short time

Epidemiology Terminology:

Worldwide epidemic

Epidemics are often associated with?

1. Acute

2. Highly-transmissible

3. Directly transmitted pathogens that either kill the host or induce strong immunity