Infection Processes Flashcards
Infection
Invasion/colonization of body by pathogenic microorganisms
Disease
Occurs when infection results in change from normal state of health
Pathogen
Microorganism/virus able to produce disease
Location of portal exit
Usually close to organism’s breeding site
Transmission of disease pathway
(1) Reservoir
(2) Portal of exit
(3) Mode of transmission
(4) Portal of entry
(5) Susceptible victim
Factors for infection
(1) Communicability
(2) Immunogenicity
(3) Pathogenicity
(4) Toxingenicity
(5) Virulence
Risk factors for susceptibility
- nutritional status
- chronic illness
- age
- immunosuppression
- environment
- HAI
Breaking the chain of infection
- destroy reservoir
- block portal of exit/entry
- block mode of transmission
- reduce victim’s susceptibility/improve immune system
- use antimicrobials with caution
Stages of infection
(1) incubation period
(2) prodromal stage
(3) invasion/acute illness
(4) convalescence
Classes of infectious microorganisms
- bacteria
- fungi
- protozoa
- virus
- helminths
Symbiosis
benefits only the host not the organism
Mutualism
benefits host and microorganism
Commensalism
benefits only the microorganism, no harm to host
Pathogenicity
benefits the microorganism, harms the host
Opportunism
Benign microorganisms become pathogenic due to decreased host resistance or translocation to other body sites
Bacteria characteristics
- cell wall
- cell shape
- movement mechanisms
- gram staining
Bacterial virulence factors
- pili
- flagella
- capsules
- enzymes
- exotoxins
- endotoxins
- antibiotic resistance
Bacteremia
presence of bacteria in the blood
Sepsis
large amount of infection in the blood
life-threatening
overproduction of pro-inflammatory cytokines
Most common bacterial infections
- pneumonia
- meningitis
- UTIs
- TB
- wound infections
Reproduction of fungi
- form spores
- detach from parent cell
- germinate into new fungi elsewhere
- colonize when normal flora are disturbed
Mycoses
infections caused by fungi
Dermatophytes
fungi that invade skin, hair, or nails
Candida albicans
most common cause of fungal infection
opportunistic yeast
Subcutaneous fungal infection
gets in tissue during trauma
Systemic fungal infection
inhalation of dust that contains fungus
Composition of viruses
RNA
- single strand
- single strand retrovirus with reverse transcriptase
- double strand
DNA
- single stranded
- double stranded
Protein shell (capsid)
Classification of viruses
- genetic makeup
- mode of replication
- structure of viral capsule (capsid)
- specific host cell that virus invades
Viral modes of replication/invasion
- adhere to cell membrane → phagocytosis → capsule opens and releases genetic material inside
- stick to cell surface and inject genetic material into host
- manufacture envelope to surround viral capsid and release virus through budding
