BACTEE - INFECTION AND IMMUNITY
Infection acquired as a result of a medical procedure
Iatrogenic
an individual's microbiologic environment, present in or on the human host (normal flora)
Microbiome
the means by which etiologic agents are brought in contact with the human host (example: infected blood contaminated water insect bite)
mode of transmission
the state of disease and its associated effect on the host
Morbidity
the incidence of a particular disease state
morbidity rate
rate death resulting from disease
Mortality
the incidence in which a disease results in death
mortality rate
infection for which the etiologic agent was acquired in a hospital or a long term health care center or facility
Nosocomial infection
a larger the normal number of deceased or infected individuals that occurs over a relative short period
Outbreak
an epidemic that spans the world
pandemic
the origin of the etiologic agent or location from which it disseminates example water food insects animals other humans
reservoir
laboratory based characterization of etiologic agents designed to establish their relatedness to one another during a particular outbreak or epidemic
strain typing
any type of epidemiologic investigation that involves data collection for characterizing circumstances surrounding the incidence or prevalence of a particular disease or infection
surveillance
a living entity (animal, insects, or plant) that transmit the etiologic agent
Vector
a specific type of infection resulted from regular interaction with animals for food production
livestock-associated
a human infection when microorganisms primarily infect animal populations and on occasion– accidentally encounter and infect humans
zoonotic infection
infectious agents from animal reservoirs are transmissible directly to humans through an animal bite or indirectly through the bite of insects vectors that feeds on both animals and vectors
Animals as microbial reservoirs
intervening agents
vectors and vehicles
modes of transmission
direct and indirect
Humans, animals, food (from plants and animal sources), water, air, soil.
Microorganism sources or reservoir
a living entity that is contaminated with the etiologic agent and such is the mode of transmission for that agent
vehicle
direct is transmitted by direct contact between reservoir and host
direct MOT
transmitted to host via intervening agents
indirect MOT
Factors that determine the composition of the usual microbial biota (mahon)
- amount and types of nutrients available in the environment
- ph
- oxidation-reduction potential
- resistance to antibacterial substance
microorganisms that are present at a site temporarily
transient microbiota
microorganisms that colonize an area for months and years
Resident microbiota
are commonly found on or in body sites of healthy persons
Normal flora
is a relationship in which one organism (parasite) benefits at the expense of its host
parasitism
A relationship in which one organism benefits while there is no beneficial or harmful to the other organism
Commensalism
a symbiotic relationship in which both organisms benefit from each other
mutualism
defined as the association of two organisms living together
symbiosis
is the growth of microbiota in or a body site without the production of damage or notable symptoms
Colonization
infection ectoparasites cause
infestation
microorganism that are able to survive on the skin of the host without gaining access to intestinal tissues
ectoparasites
the most common role of insects (arthropods) in the transmission of infectious disease is as vectors rather than as reservoirs
insects as vectors
role of the microbial biota in the host defense against infectious disease
- develop immunologic competence
- blocks colonization
- produce bacteriocins
- metabolic by-products
Causes of opportunistic infection
- alteration of habitat
- host immune system is compromised
- overuse and misuse of antibiotics
Cause opportunistic infection (an infection that does not normally cause disease or damage in a host but under specific conditions or opportunities causes pathology or disease)
Opportunist
Certain members of the normal flora are ___
opportunist
microbiota____ since the immune system is constantly primed by contact with microorganisms
develop immunologic competence
microbiota produces a___ that blocks colonization by extraneous pathogens (competition for space and nutrients)
micro environment
some microbiota produce___inhibits the growth of closely related bacteria
bacteriocins
some microbiota produce___that results in a micro environment–hostile to potential pathogen
metabolic by-products
enzyme produced by bacteria that aid in the spread of infection and disease (hyaluronidase, coagulase, collagenase, hemolysin)
enzymatic factors
toxins are substances produced by pathogenic microorganisms causing tissue and cellular damage
toxic factors
toxic factors
endotoxin and exotoxin
enzymatic factors
- hyaluronidase
- coagulase
- collagenase
- hemolysin
Toxic virulence factors
toxic factors
enzymatic factors
cellular structure
> organisms that can establish infection with a ___ are considered more virulent than organisms that require high numbers for infection
relatively low effective dose
usually measured by the numbers of microorganisms necessary to cause infections in the host
Virulence
The relative ability of a microorganism to cause disease or the degree of pathogenicity
Virulence
the ability of a microorganism to produce disease in an individual
Pathogenicity
Pathogenicity
>true pathogens
>opportunistic pathogens
first step of infection and disease development
Adherence
Factors that influences violence
factors
adherence
proliferation
tissue damage
production of toxins
invasion
dissemination
provides an additional protection to the bacteria (example: capsule - resist phagocytosis)
cellular structure
comprise one or more virulence associated genes and mobility genes (example: integrases and transposases) that mediate movement between various genetic elements (example: plasmids and chromosomes) and among different bacterial strains
Pathogenicity islands
mobile genetic elements that contribute to the change and spread of virulence factors among bacterial population of a variety of species
Pathogenicity islands
genomic region found in pathogenic microorganisms where virulence factors are encoded
Pathogenicity islands
spread of Microorganisms to distant body sites
dissemination
process of penetrating and growing in tissues
invasion
noticeable manifestation of disease or infections occurs
Tissue damage
a result of either performed toxin or the disruption of the normal functioning of the intestinal cells
Tissue damage
have IgA protease
H. influenzae, N. gonnorhoeae
degrades the IgA at mucosal surfaces
IgA protease
uses lactoferrin as a source of iron (not inhibited by the presence of lactoferrin)
Neisseria meningitidis
Neisseria meningitidis uses ___ as a source of iron
lactoferrin
produced by the host as a way to protect against infection
secretory antibody lactoferrin and lysozyme
a pathogen must multiply following its attachment to host cells in order to establish and cause a disease
Proliferation
adhere to host cell surfaces increasing pathogens colonizing ability
fimbriae/pili and surface polysaccharides
main adhesins in bacteria
fimbriae/pili and surface polysaccharides
must possess the necessary receptors for the adhesins
host cells
microbial surface structures that mediate attachment are called
Adhesins
factor that influence virulence factors in which the source is gram positive/negative
exotoxin
factor that influence virulence factors in which metabolic producut is released by living cell
exotoxin
factor that influence virulence factors in which the genetics is carried by plasmids or bacteriophages
exotoxin
factor that influence virulence factors in which the chemistry are simple proteins and peptides
exotoxin
factor that influence virulence factors in which is destroyed rapidly at 60 degC except ___
exotoxin , staphylococcal enterotoxin
factor that influence virulence factors in which it is highly immunogenic--converted to toxoids for vaccines
exotoxin
factor that influence virulence factors in which the signs and symptoms are specific. give 3 examples
exotoxin. cytotoxic, neurotoxic, enterotoxin
factor that influence virulence factors in which it has various mode of action
exotoxin
factor that influence virulence factors in which it has high toxicity
exotoxin
factor that influence virulence factors in which it has low lethal dose. how much dose?
exotoxin, 1 mg
give examples of exotoxin
tetanus/lock jaw; botullism
factor that influence virulence factors in which its source is gram negative
endotoxin
factor that influence virulence factors in which its release is upon the lysis of the cell
endotoxin
factor that influence virulence factors in which its genetics is synthesized by bacterial chromosome
endotoxin
factor that influence virulence factors in which its chemistry is lipid A
endotoxin
factor that influence virulence factors in which its stable at 100 degC for 1 hour
endotoxin
factor that influence virulence factors in which it's poorly antigenic
endotoxin
factor that influence virulence factors in which its signs and symptoms is general/non-specific. give 3 examples.
endotoxin. fever, shock, hypotension
factor that influence virulence factors in which its mode of action includes TNF, IL-1, IL-6
endotoxin
factor that influence virulence factors in which it has low toxicity
endotoxin
factor that influence virulence factors in which it has high lethal dose
endotoxin
provide examples for endotoxin
UTI, Meningococcemia sepsis
results when the infection produces notable changes in human physiology specifically that cause damage to the organ system
disease
a specific disorder that is characterized by a recognizable set of signs and symptoms which are attributable to heredity, infection, diet, or environment
disease
bodily invasion of pathogenic microorganism that reproduce multiply and cause disease
Infection
Involves the growth and multiplication of microorganisms that cause damage to their host
Infection
may form from monomicrobic irrigation or polymicrobic aggregation
biofilm formation
An accumulation of microorganisms embedded in a complex matrix composed of proteins, polysaccharides, extracellular DNA (eDNA), and other molecules
Biofilm formation
A group of community of microorganism capable of adhering to each other or to other services
Staphylococcus aureus, Pseudomonas aeroginosa, salmonella species, Citrobacter koseri
test that detects gram negative endotoxin
limulus lysate test
Test to detect and the toxin in body fluids and surgical instruments
Limulus lysate test
Limulus lysate test reagents
blood of horse shoe crab, Lymulus polyphemus
limulus lysate test Principle: In the presence of ___ amoebocytes (white blood cells) release lysate (protein) + __
endotoxin, clumping
types of infection according to host distribution
focal infection
local infection
systemic/generalized infection
- bacteremia
- septicemia
- Pyemia
- toxemia
presence of toxins in the body
toxemia
pus-producing organisms repeatedly invade the bloodstream and localized at different parts of the body
Pyemia
active multiplication of the invading bacteria in the blood
septicemia
presence of bacteria in the blood (invade in the bloodstream without active multiplication)
bacteremia
microorganisms spread throughout the body causing infection via blood or lymph
systemic/generalized infection
starts as local infection before spreading to the other parts of the body
focal infection
means sight and symptoms are combined in one area
local infection
extent of infection
Acute infection
latent infection (silent phase)
chronic infection
an infection which progresses slowly from weeks to a period of years
chronic infection
clinically silent inside the body and causes no noticeable illness in the host (then a severe and acute infection manifests)
latent infection (silent phase)
develops rapidly and usually with a short duration
Acute infection
a group of signs and symptoms that are associated with disease
syndrome
examples of symptoms
pain, headaches, nausea, fatigue
indicators as described by the patient >subjective
symptom
increases in body temperature (fever) or the development of a rash or swelling
sign
measurable indications or physical observations
objective
sign
Phases of infection infectious disease
incubation period
prodromal period
clinical or illness period
decline period
convalescent period
in which the surviving host is recuperating towards full recovery or chronic infection develops or death
convalescent period
signs and symptoms begin to subside as a host condition improves or deteriorates possible to death
decline period
peak of characteristics of signs and symptoms of an infection or a disease
clinical or illness period
period of appearance of signs and symptoms
prodromal period
time between the exposure to a pathogenic organism and onset of symptoms (no signs and symptoms)
incubation period
Host resistance factors
innate or natural immunity
adaptive or specific immunity
-humoral immunity
-cellular immunity
occupation of specialized T - lymphocytes
cellular immunity
production of antibodies
humoral immunity
3rd line of defense
adaptive or specific immunity
innate or natural immunity
physical barriers
cleansing mechanisms
antimicrobial substances
normal microbiota
phagocytosis
inflammation
line of defense
adaptive or specific immunity
humoral immunity
cellular immunity
# of living organisms = # of dead organisms
Stationary phase/plateau phase
this period is when there is a balance between cell division and dying organisms although the number of viable microorganisms remains constant
Stationary phase/plateau phase
phase in which microorganisms are utilized in physiological, biochemical and antimicrobial testing
Log phase/exponential phase
stage in which the bacteria increase logarithmically since cellular production is most active during this period
Log phase/exponential phase
period when microorganisms are actively growing and dividing
Log phase/exponential phase
cells are very active metabolically but no increase in cell mass; preparing to divide
start of biosynthesis
start of biosynthesis period
Lag phase period/rejuvenescenes
period where there is no cell division or an abrupt increase in the cell number
Lag phase period/rejuvenescenes
the period of adaptation (adjustment phase) of the organism to their new environment characterized by little or no multiplication
Lag phase period/rejuvenescenes
obtained by plotting the logarithm of the number of cells against the time of growth
Bacterial growth curve
is the time required for bacteria to double their population
generation time or doubling time
defined as the doubling of the cell number
Generation
30 - 300 colonies (non-aggregate cells) should be counted
Enumeration of bacteria in milk food and water
plate count
determines the CFU/mL of bacteria
plate count
measure the number of viable cells
plate count
most commonly used method of growth measurement by cell count
plate count
method that does not distinguish between living and dead cells
microscopic count
a measured volume of a bacterial suspension is placed on a microscope slide or on a counting chamber
microscopic count
methods of growth measurement by cell count
microscopic count, plate count
microscopy, use of electronic particle counter, or colony count
by cell count
stage in which there is a loss of nutrients and increase in the amount of toxic waste
Death phase/decline phase
period when there is cessation of bacterial growth as a number of dead cells exceeds the living microorganisms
Death phase/decline phase
Growth cease in stationary phase bcs
-exhaustion of nutrients
-accumulation of toxic metabolic products
slowing down of metabolic activities of surviving cells
exhaustion of nutrients
the degree are starting to accumulate
accumulation of toxic metabolic products
enumeration of bacteria in milk and vaccine
microscopic count
microscopic counter for bacteria in milk
breed count method
microscopic counter for prokaryotes
Petroff-Hausser counter
microscopic counter for prokaryotes and eukaryotes
hemocytometer
weighing, measuring the nitrogen content, and turbidimetry
By cell mass
observing biochemical activity
By cell activity
(it requires ____ cells/ml)
used to prepare the standard in a kilo for antimicrobial testing
turbidimetric method, 10 - 100 million
For filamentous organisms/fungi
dry weight determination
Methods of growth measurement by cell mass
dry weight determination
turbidimetric method
Methods of of growth measurement by cell activity
biochemical activity
enumeration of bacteria in milk
biochemical activity
Autotrophs can obtain energy through
photosynthetically
oxidation of inorganic compounds
oxidation of inorganic compounds
chemolithotrophs
autotrophs that obtain energy photosynthetically
phototrophs
use carbon dioxide as a sole carbon source with only water and inorganic salts as substrates
autotrophs
reduce in inorganic molecules for energy conservation/biosynthesis
autotrophs
also known as lithotrophs
autotrophs
makes up additional 4% of the weight
phosphates for nucleic acid
phospholipids for cell membranes
sulfur for protein synthesis
for carrying out cellular functions
ATP
source of energy
ATP
makes up 14% of the bacteria
nitrogen
used by bacterias for making proteins
Nitrogen
represents 50% of the dry weight of the bacterium
carbon
bacs use for making cellular components
carbon
Major nutritional needs of bacteria
Carbon, nitrogen, ATP
do not require the presence of oxygen and they die after prolonged exposure to air. Give examples.
obligate anaerobes
Clostridium and Bacteroides
the atmosphere in anaerobes jars bags or chambers is composed of
5% to 10% hydrogen
5% to 10% carbon dioxide
80% to 90% nitrogen
0% oxygen
cannot grow in the presence of oxygen
Anaerobes
do not require oxygen to grow and survive
Anaerobes
organisms require oxygen and grow well with room air
grows in ambient air which contains__oxygen and a small amount (__) of carbon dioxide, (Mahon: __ CO2). give examples.
Aerobes, 21%, 0.03%, 0.04%
Bordetella, Brucella, Mycobacteria, Pseudomonas
According to oxygen requirement
aerobes, anaerobes, capnophiles, microaerophiles
bacs according to carbon source/electronsource/energysource
autotrophs, heterotrophs
all bacteria that inhabit the human body belongs to this category
heterotrophs
require an organic source of carbon (__) and obtain energy by either oxidation or fermentation
heterptrophs, Glucose
also known as organotrophs
heterotrophs
require organic substance for growth and multiplication
heterotrophs
detrimental to cell components such as proteins and nucleic acids
hydroxyl radical
most potent biological oxidant known
hydroxyl radical
short lived
hydroxyl radical
__ reacts with __in the presence of __ to generate the hydroxyl radical
superoxide anion, hydrogen peroxide, iron
Super oxide an ion + hydrogen in the presence of iron =
hydroxyl radical
Why does some organisms are anaerobic?
this is because molecular oxygen is reduced to superoxide anion (O2-) and hydrogen peroxide (H2O2) in a stepwise manner by the addition of electrons
organisms can survive in the presence of oxygen but unable to perform metabolic processes unless situated in an anaerobic environment. give examples.
Aerotolerant anaerobes
Lactobacillus and Cutibacterium
organisms that can grow either in the presence or absence of oxygen; hence they are considered as “____”. give examples.
facultative anaerobes, aerobes that can grow anaerobically
Enterobacteriaceae
most clinically significant bacteria
facultative anaerobes
Presence of O2 -
Absence of O2 -
aerobic respiration
fermentation
an organism that requires increased CO2 (__) and approximately __ O2. give example.
Capnophiles, 5 - 10%, 15%
Haemophilus influenzae, Neisseria gonorrhoeae, Streptococcus pneumoniae
can be achieved by candle jar, CO2 incubator, chamber or bag
capnophiles
an organism that requires only __ oxygen for growth (decreased O2; Bailey’s: __) and increase CO2 (bailey’s: __)
give examples.
Microaerophiles, 2 - 10%, 5 - 10%, 8-10%
Campylobacter, Helicobacter and Treponema
lack superoxide dismutase and catalase therefore they are susceptible to these toxic derivatives of oxygen
Anaerobes
breaks H2O2 to O2 and water
catalase
converts the superoxide anion to oxygen and H202
superoxide dismutase
Cells need a way to remove Superoxide anion and hydrogen peroxide:
aerobes and facultative anaerobic bacteria have superoxide dismutase and catalase
the optimum ph for most pathogenic bacteria is from ph__ to __
6.5 to 7.5
measures of the hydrogen ion concentration
ph scale
bacs According to pH requirement
acidophiles, neutrophils, alkalophiles
prokaryotes that are able to survive in unusual conditions like the absence of oxygen increase temperature and living below the surface of the earth. give examples.
Extremophiles
Bacillus infernus - strict anaerobe
strict anaerobe
Bacillus infernus
Thermophiles/hyperthermophiles grows at __-__ deg C. give examples.
50 to 60°
Geobacillus stearothermophilus, Thermus aquaticus
Mesophiles grows between at__ - __degrees celsius
20 to 45
most commonly encountered pathogenic bacteria
mesophiles
psychrophiles/cryophiles grows well at __ -__° c (average __° C). give examples.
1 to 20, 10
Listeria monocytogenes and Yersinia enterocolitica
The optimum temperature for most chemically significant bacteria is __ degrees celsius
35 to 37
bacs According to temperature requirements
Psychrophiles/cryophiles
mesophiles
thermophiles/hyperthermophiles
extremophiles
NAD/coenzyme I (heat labile). produced by some bacteria:
V factor
Staphylococcus aureus, S. pneumoniae, Neisseria, or from potato or yeast extract
hemin (heat stable) oxidized form of hemoglobin
X factor
growth factors
X and V factors
is a growth factor especially in Haemophilus influenzae
blood
example of growth factors
amino acid
purines
pyramidines
vitamins
fatty acids
organisms that require complex nutritional requirement or growth factors in order to grow (blood)
Fastidious
are substances that are required by fastidious bacteria for their growth and multiplication
growth factors
organisms that require and grow in increased concentration of sodium chloride. give examples.
Halophiles
Listeria monocytogenes, staphylococcus aureus, Vibrio spp. (except Vibrio cholerae and Vibrio mimicus)
According to inorganic salt concentration
Halophiles
organism requiring increased moisture content
humidophiles
it serves as a solvent for food and forms the major portion of the protoplasm
Moisture
This is indispensable for bacterial growth
Moisture
According to moisture
Humidophiles
alkalophiles grow between ph __ - __. give an example
8.5 to 11.5, vibrio
neutrophiles grow between ph __ - __
5.5 to 8.0
most clinically significant bacteria
neutrophiles
Acidophiles grow between pH __ - __. give an example.
0 - 5.5, Lactobacillus acidophilus
diagnostic laboratory culture media for bacterial isolation are usually adjusted to a final ph between __ - __
7.0 and 7.5