Infection Flashcards
what are some CONCERNS regarding infectious diseases?
- greater emergence of PREVIOUS UNKNOWN INFECTIONS
- a REemergence & SPREAD of old infections
- greater RESISTANCE to multiple antibiotics
what is the RELATIONSHIP between humans and microorganisms?
- creation of a NORMAL HUMAN MICROBIOME
- human body becomes a PRIMARY SITE OF GROWTH
- provides NUTRIENTS / produces ENZYMES for human digestion
- maintained by PHYSICAL BARRIERS
where can MICROORGANISMS be found on the human body?
- skin
- mouth
- gi tract
- resp. tract
- gu tract
symbiosis / symbiotic relationship
benefits only the HUMAN, no harm to the microorganism
mutualism
benefits BOTH HUMAN & MICROORGANISM
parasitism
benefits the MICROORGANISMS; HARMS the HUMAN
opportunism
- situation where BENIGN MICROORGANISMS become PATHOGENIC because of DECREASED HUMAN HOST RESISTANCE/translocation to other body sites
- seen when BARRIERS/DEFENSE SYSTEMS of the body grow WEAK
example of opportunism
- ex. antibiotics - can cause greater growth of opportunistic microorganisms and cause disease
- C. diff
- ex. autoimmune patients
what are the FIVE STEPS in the process of INFECTION?
- ENCOUNTER & TRANSMISSION
- COLONIZATION
- INVASION
- DISSEMINATION
- CELLULAR/TISSUE DAMAGE
what are the types of TRANSMISSION?
- can be either DIRECT or INDIRECT
vertical transmission
mom to child transmission during birth from the placenta
ex. Listeria monocytogenes, CMV
horizontal transmission
seen with transmission of blood, body fluids
spread from one person to another/animal
ex. HIV, zoonotic infections
indirect transmission
contact with INFECTED NON-LIVING MATERIALS
- towels, toys, bandages, doorknobs
contact with INHALATION/DROPLETS
ex. flu, pneumonia
contact with CONTAMINATED ITEMS
ex. cholera, gastroenteritis
definition of COLONZATION
- the ability of a PATHOGENIC MICROORGANISM to SURVIVE and MULTIPLY on or within the human environment
- competing with SYMBIOTIC MICROORGANISMS and RESISTING LOCAL DEFENSES
adherence
- helps to PROTECT the microorganism from REMOVAL from mechanical, non-mechanic, coughing forces
- often seen between RECEPTORS of the surfaces of cells/microorganisms
biofilms
- mixed species of microorganisms that have a HIGHLY ORGANIZED EXTRACELLULAR MATRIX produced by the microorganisms
- become more TOLERANCE & RESISTANT to antibiotics & immune responses
- can form ANYWHERE - medical devices (pacemakers, prosthetics, catheters)
invasion
- the ability of PATHOGENS to cross SURFACE BARRIERS including the SKIN & MUCOUS MEMBRANES
- needs PENETRATION to BREAK THE INTEGRITY of the surface barrier
dissemination
spread of infection that can occur by DIRECT EXTENSION through surrounding tissue or through the blood/lymphatic vessels
cellular/tissue damage
production of TOXINS or indirect results due to immune responses of inflammation, swelling, scarring, or necrosis
endogenous microorganisms
- already present within the body
- part of the normal microbiome
exogenous microorganisms
- transmitted from an EXTERNAL SOURCE
- ex. contaminated water, food, human, animals etc…
endemic
disease is RELATIVELY HIGH RATE, but has constant rates in a SPECIFIC POPULATION
epidemic
number of NEW INFECTIONS in a SPECIFIC POPULATION greatly exceeds the NUMBER USUALLY OBSERVED
pandemic
epidemic spread worldwide or over large area
virulence
capacity to CAUSE SEVERE DISEASE
communicability
ability to spread disease from one person to the next
pathogenicity
ability to PRODUCE disease
infectivity
ability to INVADE & MULTIPLY in the host
what are the FOUR STAGES OF INFECTION?
- INCUBATION PERIOD
- PRODROMAL STAGE
- INVASION/ACUTE ILLNESS PERIOD
- CONVALESCENCE PERIOD
incubation period
- time from initial exposure - onset of first symptoms
- have initial colonization at this point; not enough growth to cause symptoms
prodromal period
- initial symptoms begin to show
- feelings of discomfort / fatigue
- multiplication of microorganisms continue
invasion/acute illness period
- RAPID multiplication of microorganisms
- possible triggers of immune & inflammatory processes
convalescence period
- removal of infectious agents
- decline of symptoms
- latency phase *
describe BACTERIA
- are PROKARYOCYTES (don’t have a nucleus)
- often SMALL
- common cause of disease
- can be AEROBIC/ANAERBOIC
- can be MOTILE or IMMOTILE
gram-positive
- have TEICHOIC ACID & THICK PEPTIDOGLYCAN LAYER
- appears PURPLE
gram negative
- have LIPOPOLYSACCHARIDES (LPS)
*endotoxin - THIN PEPTIDOGLYCAN LAYER
- appears LIGHT PINK
extracellular bacteria
- can use VIRULENCE MECHANISMS to continue spreading
- induces the FORMATION OF HUMORAL ANTIBODIES
intracellular bacteria
- can enter & survive cells - can EVADE HUMORAL ANTIBODIES
- can stay for very long and cause disease
exotoxins
- DIRECTLY INJURE CELLS by damaging cell membranes/entering cells and changing functions
- produce ANTITOXINS - important for vaccines
endotoxins
- does not produce antitoxins
- often is GRAM-NEGATIVE
- activates the INFLAMMATORY PROCESS and produces FEVER
bacteremia
when bacteria is present in the blood
sepsis/septicemia
- release of LARGE AMOUNTS OF TOXINS
- when bacteria GROWS in the blood
describe VIRUSES
- obligatory intracellular microbes that consist of NUCLEIC ACID protected by a protein shell - CAPSID
- can have DOUBLE-STRANDED DNA (dsDNA), SINGLE-STRANDED DNA (ssDNA), DOUBLE STRANDED RNA (dsRNA) or SINGLE-STRANDED (ssRNA)
how do VIRUSES replicate?
all dependent on their ability to INFECT A PERMISSIVE HOST CELL
describe ways of VIRAL TRANSMISSION
- often by ONE INFECTED PERSON to an UNINFECTED PERSON through;
- aerosols of respiratory tract fluids
- infected blood
- sexual contact
- transmission from animal reservoirs
- vectors *mosquitoes
what are the STEPS OF VIRAL TRANSMISSION?
- ATTACHMENT
- PENETRATION
- UNCOATING
- REPLICATION
- ASSEMBLY
- RELEASE
what are some AFFECTS OF VIRAL INFECTION?
- can cause inhibition of DNA/RNA/PROTEIN SYNTHESIS
- immune system can start attacking itself
- production of CANCEROUS CELLS
- secondary bacterial infectionsv
viral latency
- viruses BYPASS the intracellular defenses and HIDE within cells from immune responses
- remains DORMANT until an active response to a stimuli - can activate exit of latency, causing disease
- ex. varicella-zoster, shingles (herpes zoster)
antigenic variation
- process where viruses can avoid the IMMUNE SYSTEM by making small changes to its genes to make VIRAL SURFACE ANTIGENS
- ex. INFLUENZA
describe FUNGI
- have large eukaryotic microorganisms
- reproduce by SIMPLE DIVISON or BUDDINGS
- are AEROBIC
- yeasts - *FACULTATIVE ANAEROBES, can adapt to anaerobic conditions if need be
classification of FUNGAL INFECTIONS
- known as MYCOSES
- can be either SUPERFICIAL, DEEP, or OPPORTUNISTIC
- can cause infection around the SKIN or MUCOUS MEMBRANES
- if they invade the SKIN, HAIR or NAILS
- known as DERMATOPHYTES
what is the most common cause of fungal infections?
C. Albicans - type of an OPPORTUNISTIC YEAST
what is the most COMMON FUNGAL INFECTION in cancer patients?
candida
what are PARASITIC MICROORGANISMS?
- establishes relationships where PARASITE BENEFITS in expense of other species
- can range from UNICELLULAR PROTOZOAN to LARGR WORMS
antibiotics; can either be _____ or ______?
- natural products of fungi, bacteria, and other microorganisms that affect the growth of other microorganisms
- can be;
- BACTERICIDAL (kills the microorganisms)
- BACTERIOSTATIC (inhibits growth)
what are the MECHANISMS OF ACTION for antibiotics?
- INHIBITS FUNCTION OR PRODUCTION OF THE CELL WALL/MEMBRANE
- PREVENTS PROTEIN SYNTHESIS
- BLOCKS DNA REPLICATION
- INTERFERENCE with FOLID ACID METABOLISM
what causes ANTIBIOTIC RESISTANCE?
occurs due to the LACK OF COMPLIANCE with completing the antibiotic therapeutic regimen
