Midterm1 Flashcards
Which is the name of the theory that justify diseases by an imbalance of the 4 humours ?
Humoral (Hippocrate)
What is the name of the theory that stipulates that diseases are caused by bad air, air polluted by decaying matter?
Miasma (bubonic plague, 542 )
Who explains that diseases are caused by seeds of contagion, transfer of diseases (contagion)?
Fracatoro (1686), by observing syphilis.
Who developed the Germ Theory?
Pasteur, Henle, Lister, Koch and others.
What is the Germ Theory?
Recognition that some diseases are caused by MICROORGANISMS, thus preventing exposure to microorganisms prevents disease.
What are the 4 Koch’s postulates?
- Germ: The suspected germ must be present in every case of disease
- Isolation: The germ must be isolated and grown in pure culture
- Inoculation : The cultured germ must be inoculated into a healthy specimen and cause disease.
- Reisolation: The same germ but be reisolated.
Which is the proposed fifth postulate, missing from Koch’s?
Elimination of the microbe from the infected host\prevention of exposure eliminate\prevent disease.
What are the 4 limitations of Koch’s postulates?
- Symptoms: might not be entirely caused by microbes (host susceptibility, prior infection, risk factor.)
- Culture: not always possible or reduce virulence
- Strains: not all strains of the same sp. cause the same disease
- Reinoculation: might be problematic in humans
Who discovered Penicillin?
Alexander Fleming (1928)
What is defined by ‘‘damage to the host, usually with the manifestation of symptoms’’
Disease
Define ‘‘infection’’
Successful colonization of the host by a microorganism capable of causing damage to the body (disease)
Define ‘‘colonization’’
The capacity of a microorganism to attach and multiply at a particular site in the host
T\F
Colonization can be asymptomatic
T
Define ‘‘pathogen’’
A microorganism capable of colonizing a host and causing disease
What is defined by ‘’ the ability of a microorganism to cause disease’’
Virulence
T\F
A opportunist microorganism is capable of causing disease only when the defenses of the host are compromised
T
What is a nosocomial infection?
An infection acquired in a HOSPITAL.
T\F
A community-acquired infection is an infection acquired outside of the hospital
T
How do we call an increase of the number of cases of a disease above normal at a particular time and place?
Outbreak
What are sporadic cases?
Cases of disease appearing randomly (in time and space), without any clear connection between them. They come from different sources.
T\F
Sporadic cases come from the same sources.
F
How do we call animal diseases that can be transmitted to humans?
Zoonosis
What are the 3 results of human-microbe interaction?
- Clearance of the microbe
- Asymptomatic carriage
- Development of symptoms
What are the 3 reasons why a bacteria might infect a human?
- Disease: Bacteria are evolving to infect the host, which cause disease.
- Asymptomatic: Bacteria are trying to achieve equilibrium in the host. In the process of becoming commensals.
- Accidental host: Activation of stress responses lead to disease
Name 4 facts that explain why virulence is a complex phenomenon.
- Virulence factors: large number of virulence factors involved in the ability of the bacteria to cause disease
- Functional redundancy (between virulence factors)
- Genetic trait: can be a virulence factor for one bacteria, but not the other
- Genetic determinants: can reduce virulence
Name 5 characteristics of infectious diseases, not seen in other human diseases.
- Potential for a global impact
- Acquired immunity frequent
- Usually, no risk factors except for exposure
- Transmissible
- Potential for becoming preventable
- Potential for eradication
- Pathogens have higher replicative and mutational capacities than humans
- Linked to human behavior
- Derivation from coevolution
- Possibility of treatmants
T\F
Cancers have the potential to become eradicated
F
T\F
According to DRF, there are only microbes and hosts, and disease, commensalism or colonization are only states from their interactions.
T
What are the 3 points of a disease according to the Damage-Response Framework (DRF)?
- Infectious disease requires a microbe + host
- Interactions are required
- Disease: the outcome of this interaction is damage to the host
What is a true bacterial pathogens?
It causes disease in any individual exposed for a first time to a sufficient dose, but do not necessarily kill ever infected individual (susceptibility).
How to we call bacterial pathogens that cause disease only under specific conditions?
Opportunistic
Where are coming from emerging pathogens?
- New disease = new bacterial pathogens
- Identification of a bacterial cause for a known disease
- Evolution of a non-virulent strain
- Change in human behavior \ technology -> new opportunities for transmission
- New opportunistic pathogen due to modern medicine (weak individuals)
What are the 3 types of bacterial pathogens?
- True
- Opportunistic
- Emerging
What conditions can favorise infections by a opportunistic pathogen (4)?
- Immunocompromised individuals
- Mutation in host
- Underlying diseases
- Antibiotic therapy
What is the bacteria that causes gastric ulcers?
Helicobacter pylori
Whats an emerging pathogen?
Never seen before, newly recognize, newly evolved or reemerging.
Give an example of opportunistic pathogen?
Clostrodium difficile
What are the characteristics specific to infectious disease?
Outbreaks, potentially preventable, don’t usually depend on a lot of risk factors.
Name the 6 steps involved in bacterial infection.
- Attachment to host
- Invasion of tissue
- Colonization (establishment, replication)
- Colonization\replication cause damage
- Bacteria exit the host
- Transmission
What are the first line of defenses agaisnt bacterial pathogens?
Skin and mucosa
Name 6 tools used by the innate immune system.
- Inflammation
- Complement
- Phagocytes
- Neutrophil (extracellular traps)
- Natural Killer cells (NK)
- Apoptosis
T\F
Antibodies are part of the innate immune system
F
Antibodies are part of the adaptive immune system
T\F
CTLs (cytotoxic T Lymphocytes) are part of the adaptive immune system.
T
What kind of cells produce mucus?
Goblet cells (upper respiratory tract)
What is the special protein in stratified squamous epithelium?
Keratin (vaginal tract and skin)
Where can you find a simple squamous epithelium ?
Mouth and lungs
What is the kind of epithelium in kidney?
Simple cuboidal epithelium
What the kind of epithelium in the intestine?
Simple columnar epithelium
T\F
Endothelium is attached by tight junctions
F
Only epithelium is bind by tight junctions
What the protein involved in tight junction (mucosal epithelium)?
Occludin
Define epithelium
Epithelium = thin layers of cells that covers all surface of the body expose to the external environment
T\F
There is no tight junctions in blood vessel
T (bacteria can easily cross)
Epithelium are attached to what thin sheet of connective tissue?
Basal lamina, composed of ECM component.
Name 4 components of ECM.
- Collagen
- Laminin
- Fibronectin
- Glycosaminoglycans
What the name of the surface of the cells attached to the basal laminal?
Basolateral surface
Whats the apical surface?
The epithelium surface facing outward.
Whats a polarized epithelium cell?
It’s when the basolateral and apical surface have different protein composition.
Name 3 things that prevent pathogens to get into skin.
- Dead cells of skin
- SALT
- Microbiome
T\F
Skin is a dry, acidic and cold environment.
T. It prevents growth of many bacteria.
Name 4 defense systems of the mucosa.
- Mucus
- Defensins (antibacterial peptides)
- Antibodies (sIgA) -> protein complexes
- MALT\GALT
Whats the name of the mucus protein?
MUC2
T\F
Mucus is highly glucolysated
T
What is the target of lyzozymes?
Link bêta 1-4 between N-Acetylglucosamine and N-Acetylmuramic acid of the peptydoglycan layer
T\F
Gram - are more sensitive to lyzozymes
F
Gram + are more sensitive to lyzozymes because their peptydoglycan is exposed
Name 3 bacteria mechanisms of resistance against lyzozymes
- Gram -
- Capsule
- Proteases
T\F
Antimicrobial peptides have a negatively charged region
F
Antimicrobial peptides have a POSITIVELY charged region
T\F
Bacteria are usually negatively charged
T
Because of LPS acid
Name 4 mechanism against antimicrobial peptides
- Add positive charge
- Stabilize the membrane by adding fatty acid
- Production of peptidase
- Capsule
Name 2 things that the normal microbiota produces against phathogens
Bacteriocidins (pore-forming toxins) and growth inhibitors
Name a specific defense of tears.
Lyzozymes
Name a specific defense of stomach
Acidity
Intestine
Flow + resident bacteria
What was the big disease that developed antibiotic resistance, which was reemerging from the past in the 95s because people wouldn’t do as much prevention because of the antibiotic?
Tuberculosis
Describe a situation in which an opportunistic pathogen can cause disease.
Sit 1: Host immunity is down or affected with anoter lying disease
Sit 2: The person just has an antimicrobiotic treatment, and his microbiota is knock out.
Describe a situation in which an emergent pathogen can cause disease
Appearance of a new disease caused by a new bacterial pathogen (ex: ebola), or evolution of a non-virulent strain, identification of a bacterial from a known disease (ex. H pylori), change in human behavior and technology (bypass of a physical barrier ex: p. aeruginosa) new opportunities for transmission and modern medecine has created a pool of weak individual -> new opportunistic pathogen.
