Microbiology Lecture 1 Flashcards
Basis of infectious disease Microbiology lecture 1
a harmful organism that produces a pathology, is the definition for
Pathogen
virulence
virulence factors
commensal
opportunistic pathogen
contaminant
Pathogen
the severity or harmfulness of a disease, is the definition for
Pathogen
virulence
virulence factors
commensal
opportunistic pathogen
contaminant
virulence
factors that are produced by a microorganism and evoke disease, such as toxins. is the definition for?
· Pathogen
· virulence
· virulence factors
· commensal
· opportunistic pathogen
· contaminant
virulence factors
an organism that is part of the normal flora (endogenous), with a mutualistic relationship. is the definition for
· Pathogen
· virulence
· virulence factors
· commensal
· opportunistic pathogen
· contaminant
commensal
an organism that causes infection when opportunity/change in natural immunity changes. is the definition for
· Pathogen
· virulence
· virulence factors
· commensal
· opportunistic pathogen
· contaminant
opportunistic pathogen
an organism that is growing in a culture by accident. is the definition for
· Pathogen
· virulence
· virulence factors
· commensal
· opportunistic pathogen
· contaminant
contaminant
what does strain A indicate
Image shows that strain A is more virulent compared to strain B
Image shows that the lethal dose to kill 50% of host is 30 (strain A)
what does strain B indicate
Image shows that the lethal dose to kill 50% of hosts in 50 (strain B)
Image shows that strain B is less virulent compared to strain A
an infective material derived from outside the patients body to cause infection is known as?
exogenous infection
where would an endogenous infection occur
infection would occur within host
Bacteria that is commensal has taken advantage due to lower immune response
is an example of exogenous/endogenous
endogenous
bacteria that transfers from a non-sterile location (mouth) to a sterile location (heart) is an example of
exogenous/endogenous infection
endogenous infection
: the microorganisms in a particular environment (including the body or a part of the body).
is called what
microbiome
which type of bacteria dominates the oral cavity
streptococci
the manner of development of a disease. Endogenous bacteria shifting to a parasitic lifecycle requires adaptation. is the definition of
pathogenesis
which branch of biology deals with the relations of organisms to one another and to their physical surroundings.
ecology of bacteria
which relationship best describes - saprophytic (feed on dead organic material)
free living
which relationship best describes - a symbiotic relationship, when host & organism gain mutual value
mutualistic
which relationship best describes - organism gains advantage but host does not gain from association
commensal
which relationship best describes - live on or in living creatures causing harm/damage to host
parasitic
dynamic relationship between host and pathogen, can result in a shift between what for a pathogen
shift between mutalism and paratism
illness or treatment can shift a mutalistic relationship to what
parasitic relationship
what is your carrier state if you are: showing overt clinical presentation
Active • Convalescent • Healthy • Incubator
active
what is your carrier state if you are: recovering but still cariier
Active • Convalescent • Healthy • Incubator
convalescent
what is your carrier state if you are: showing no overt signs of illness
Active • Convalescent • Healthy • Incubator
healthy
what is your carrier state if you are: maintaining large number of pathogens prior to illness
Active • Convalescent • Healthy • Incubator
incubator
pathogens exit hosts through two mechanism
what are they
Natural: through sneezing and, shedding
Artificial: blood, saliva, aerosols (drill)
spread of from a child via breastfeeding is a type of what spread
vertical transmission
how does adhesion of a pathogen contribute to its ability to cause disease
- enables binding of the organism to host tissue, helps promote colonisation
how does Invasion of a pathogen contribute to its ability to cause disease
enables the organism to invade a host cell/tissue
where it can replicate its material and spread - virus
destroy the cells and release endotoxins - bacteria
how does Impeding of a pathogen contribute to its ability to cause disease
enables the organism to avoid host defence mechanisms
how does Aggresin of a pathogen contribute to its ability to cause disease
causes damage to the host directly
how does modulin of a pathogen contribute to its ability to cause disease
induces damage to the host indirectly (via immune system)
the study of the occurrence, spread and control of disease (any disease) is the definition of what
epidemiology
the occurence and spread of disease at low levels randomly is classified as
sporadic
the occurence and spread of disease at low levels present all the time is classified as
endemic
the occurence and spread of disease at high levels in geographically one continent is classified as
epidemic
the occurence and spread of disease at high levels in geographically 2 or more continents is classified as
pandemic
surface molecules can have multiple roles such as;
attachment/ colonisation, what is the function of this role?
these pathogens function is to attach to the surface and start colonising the surface, these would be the 1st layer bacteria
surface molecules can have multiple roles such as; rafting/co-aggregation
what is the function of this role?
allows different molecules to attach to the surface molecules
surface molecules can have multiple roles such as;
signal transduction, what is the function of this role?
allows communciation with cells and within cells for a desired outcome.
bacterial mechanisms are used to avoid host defences.
what is the function of proteases produced by bacteria
proteases target secretory IgA (this is usually in mucosal surfaces, such as tears, respiratory, genital tract and saliva)
what is the function of toxins produced by bacteria
destroy immune cells
what is the function of endotoxins produced by bacteria
interfere with inflammatory response, which can induce inflammation and fever as an immune response
bacterial mechanisms are used to avoid host defences.
what is the function of capsules, mechanisms that inhibit complement, produced by bacteria
evade innate immunity
bacterial mechanisms are used to avoid host defences.
what is the function of antigen varition produced by bacteria
overcome acquired responses
metastasis is an example of what type spread of infection
superficial/systemic spread
lymes disease (tick bite) or malaria is an example of what type of spread of disease
spread of disease via contact or injection
spread of infection from cell to cell is an example of what type of spread
extra or intra cellular spread
migration of pathogens from the mouth to the heart via blood system. can cause which secondary infectious disease in the heart
endocarditis
a bacteria having a thin peptidoglycan layer determines what
that it is a gram -ve bacteria
a bacteria having a thick peptidoglycan layer determines what
the bacteria is a gram +ve
if a bacteria has no outer lipid membrane is it gram -ve or +ve
gram +ve
if a bacteria has an outer lipid membrane is it gram -ve or +ve
gram -ve
what colour would gram -ve bacteria appear under a light microscope
would appear pale reddish colour
This is because the structure of their cell wall is unable to retain the crystal violet stain so are coloured only by the safranin counterstain
what colour would gram +ve bacteria appear under a light microscope
have a distinctive purple appearance
. This is due to retention of the purple crystal violet stain in the thick peptidoglycan layer of the cell wall
the release of cytokines in to the bloodstream, which then make there way to the hypothalamus. resulting in an inflammatory response to the whole body instead of the local site - is known as what
septic shock
the continum od host response to infection - arrange in right order
sepsis
infection
septic shock
severe sepsis
infection
sepsis
severe sepsis
septic shock
what is released , which increases the bodys thermal set point
prostaglandin e
what is the bodys natural response when the bodys thermal set point is increased
the body now percieves that it is cold and starts to shiver to conserve heat.
during the sepsis stage
Small blood vessels become “leaky” and lose fluid into the tissues, what does this do to the blood volume
reduces the blood volume
lower blood volume results in the heart to do what
work harder to maintain oxygenation of tissues thus increasing heart rate
during sepsis stage, poor oxygen perfusion means less essential organs will be shut down
which organs are slowly shut down and which organ is prioritised
prioritised = brain
shurt down = kidneys, skin, liver
during the sepsis stage the blood clotting system is activated.
what are the risk of this
- causes blood clotting in tiny blood vessels, increased risk of haemorrhage.
what are the 4 symptoms of oral abscesses
Pain
Swelling – increase in immune cells in location. Pressed against nerve which causes pain.
Erythema - redness of the skin due to accumulation of vasculature
Suppuration – formation of puss.
what is cellulitis
is a common, potentially serious bacterial skin infection.
Cellulitis usually affects the skin on the lower legs, but it can occur in the face, arms and other areas
caries
gingivitis
periodontitis
pericoronitis
are examples of what
prokaryotic infections of the mouth
if caries of the tooth was not treated and further progressed what type of abscess coul it lead to -
periapical or dentoalveolar abscess
prokarotic infection of the gingiva leads to what
gingivitis
periodontal disease if left to progress
prokaryotic infection of the space between the tooth and the gingiva (periodontal space) leads to development of which dental abscess
periodontal abscess
infection of the gingivae covering partially erupted tooth leads to which pathology
pericoronitis
which type of dental abscess forms - at the apex of the root
periapical abcess
which type of dental abscess forms - in the space residing between two teeth?
gingival abscess
which type of dental abscess forms - in a periodontal pocket
periodontal abscess
which type of dental abscess forms - around impacted or partially erupted tooth
pericoronal abscess
what would be the treatment options for types of dental abscess
drainage of pus
antibiotics
treatment - root canal
worse case scenario - extraction
what could serious infections of dental abscess lead to
access to soft tissues - development of cellulitis
direct spread - near area of infection
indirect spread - through the vascular system - development of endocarditis
a bacterial complex that involves greater than 4 species of bacteria is known as
polymicrobial
bacteria that don’t grow under laboratory conditions, making it impossible to characterise and understand them. are known as
unculturable microbes
an organism that makes ATP by aerobic respiration if oxygen is present but can switch to fermentation if oxygen is absent. is known as a what
faculative anaerobe
microorganisms killed by normal atmospheric concentrations of oxygen (20.95% O2). And can only survive in environments with lack of oxygen. are known as
obligate anaerobes
are periodontal abscesses asociated with a healthy or a non vital pulp
healthy pulp
where must infection occur for a periodontal abcess to occur
in the periodontium
periodontal abscess are usually associated with which gram bacteria
gram -ve
Endodontic infections: pulpitis and recurrent infection following root canal treatment - are associated with which type of gram bacteria
gram -ve
what is a dry socket
is when the blood clot at the site of the tooth extraction fails to develop, or it dislodges or dissolves before the wound has healed.
what is osteomyelitis
inflammation of the bone marrow
what would be used prior to and post extraction to eliminate pathogens in the oral cavity
chlorohexidine irrigation
antiseptic dressing and metronidazole would be used when
dry socket
what allows an osseointergrated implant to migrate with osteoblasts and supporting tissue
the implant contains pores.
where would you find in its greatest concentration actinomyces in the oral cavity
supra and subgingival plaque
what type of caries is actinomyces associated with
root surface caries
name this oral pathogen
actinomyces
a flexible spirally twisted bacterium is known as a
spirochetes
Treponema denticola and what other pathogen found commonly associated with each other.
P. gingivalis
treponema denticola is one of two most significant species found in where
dental plaque
Symptoms – inflammation, spontaneous bleeding, intense pain and clear evidence of tissue destruction
are symptoms of which disease
acute necrotising gingivitis
how would you treat necrotising gingivitis
- Intense local oral hygiene – use of ultra scaler
- Oral hygiene advice and mouth-rinses – chlorhexidine
- Short course of antibiotics – metronidazole therapy 200mg for 5 days
ludwigs angina is an example of what disease
acute cellulitis
ludwigs angina results in the swelling of the airways, how would you treat this condition
High dose antibiotic treatment – intravenous penicillin
the skin enviroment allows for the defence agaisnt invasion of pathogens.
what are the features of the environment
- Periodic drying – allows for dormancy
- Moist areas – scalp, ears, Genito-urinary tract
- Acid pH
- High salt (hyperosmotic)
- Inhibitory substances – lysozyme
what has this SSTIs been abbreviated from
skin and soft tissue infections
Staphylococcus and Corynebacterium are most commonly isolated from which sites on the body/skin
moist sites
Staphylococci: two common species distinguished as coagulase positive/negative
What is coagulase positive/negative:
coagulase is an enzyme that enables the conversion of fibrinogen to fibrin which is needed to make blood clot. Coagulase negative means the bacteria in question does not posses the enzyme.
Staphylococci is a gram +ve cocci and is coagulase positive
is S. aureus: is coagulase positive/negative
gram +ve
coagulase positive
is Staphylococcus. epidermidis: coagulase negative or positive
coagulase negative
gram +ve
what is Methicillin-resistant Staphylococcus aureus abbreviated to
MRSA
what is MRSA
is a bacterium that causes infections in different parts of the body
the symptoms of MRSA vary, why is this
The symptoms of MRSA depend on where you’re infected
a class of antigens that results in excessive activation of the immune system. Specifically, it causes non-specific activation of T-cells. are known as
superantigens
where does the superantigen bind on to
binds outside the conventional binding groove, which results in massive release of cytokines and inappropriate immune responses. (cytokine storm)
vancomycin would be used for the treatment of which disease
MRSA
patients that are allergic to penicillin would be given what instead
erythromycin
most significant pathogenic streptococci is known as?
group a streptococcus
Group A streptococcus is a bacterium often found in the throat and on the skin. People may carry group A streptococci in the throat or on the skin and have no symptoms of illness. Most GAS infections are relatively mild illnesses such as “strep throat,”
- Anginosus
- Pyogenic
- Bovis
- Salivarius
- Mutans
- Mitis
are all what
streptococcus evoluntionary groupings
the rupture or destruction of red blood cells - is known as what
haemolysis
partial haemolysis in blood agar caused by streptococci is known as what haemolysis
alpha haemolysis
complete haemolysis in blood agar is caused by pathogenic streptococci. this is known as what haemolysis
beta-haemolysis
y-haemolysis is indicated as what in the blood agar
blood agar will show no haemolysis of blood
is streptococcus pyogenes a superantigen or not
superantigen
what gram bacteria is streptoccus pyogenes
gram +ve
thick peptidoglycan
skin infections
upper respiratory tract infections
rheumatic fever
glomerular nephritis
are all examples of pathology caused by which pathogen
streptococcus pyogenes
- Mechanical washing
- Cough response
- Mucocilliary clearance
- Microbiota/flora
the above are examples of what type of defence
upper respiratory tract defence
what helps the spread of pathogens in multiple myeloma
M protein
tissue penetration/spread is known as what
metastasis
pharyngitis is known as
sore throat
- Streptococcus pyogenes
- Bordetella pertussis
- Corynebacterium diptheria
- Haemophilus influenza
are examples of what type of respiratory infections
upper respiratory tract infections
- Haemophilus influenza
- Streptococcus pneumonia
- Mycobacterium tuberculosis
are examples of what type of respiratory infection
lower respiratory tract infections
whooping cough is usually associated with which demographic
children
whooping cough is caused by which pathogen
bordetella pertussis
what does bordetella pertussis attach to in the respiratory tract
to the ciliated epithelial cells
Bordetella pertussis produces a toxin which destorys leucocytes, what is the name of the toxin
pertusis toxin
how would you diagnosis Bordetella pertussis.
- Use cough – hold BG culture plate in front of mouth when coughing
- Perinasal swab for posterial pharyngeal walls.
- Erythromycin for 14 days
- Skilled nursing, remove mucus and vomit
- Antibiotic therapy for secondary infections
- Vaccination (diptheria, tetanus, whooping cough, polio & Hib)
are methods of treatment for which disease
Bordetella pertussis - whooping cough
what are the early symptoms of diptheria
sore throat
low fever
swollen neck glands
what are the late stages of diptheria associated with
airway obstruction
breathing difficulty
outbreaks of diptheria are associated with?
unsanitary/crowded conditions
immunity gap
vaccination failure
name the bacteria
Corynebacterium diptheriae
pathogen under the microscope looks like cantonese alphabet
- gram -ve bacilli
- Infection from respiratory droplet or direct contact with patient
- Bacteria attach to epithelial cells
- Organism penetrates to submucosa (nasopharynx)
- Causes local inflammation & swelling
- Spreads from initial site to infect bones, joints, CNS (meningitis)
which bacteria is being described
haemophilus influenza
Haemophilus influenza can cause a range of various diseases, such as;………………
is a serious bloodstream infection, also known as blood poisoning. ……………. occurs when a bacterial infection elsewhere in the body, such as the lungs or skin, enters the bloodstream.
septicaemia (44%)
Haemophilus influenza can cause a range of various diseases, such as; ………………
is an inflammation of the membranes (meninges) surrounding your brain and spinal cord. Haemophilus influenza needs to cross blood brain barrier to cause …………..
meningitis (10%)
Haemophilus influenza can cause a range of various diseases, such as; …………….
is an infection in one or both lungs. Bacteria, viruses and fungi cause it. The infection causes inflammation in the air sacs in your lungs, the alveoli fill with fluid or pus making it difficult to breathe.
pneumoniae (31%)
why cannot tuberculosis survive outside the host
because it is an obligate pathogen
mycobacterium tuberculosis penetrate deep into the lung alveoli and form initial lesions. what are the next stages of the disease
infected macrophages are phagocytosed, which infects further cells.
this results in persit and replication
induce localised immune response
cells are destroyed
granulomatus lesions are formed
- Night fever/sweats
- Malaise – general feeling of discomfort, illness or unease
- Weight loss (appetite)
- Cough
- Productive cough sputum
are the symptoms of what
pulmonary TB
what are the treatment and control of pulmonary TB
antibiotic cocktail treatment
vaccination - no longer needed in uk since 2005
When an individual bacterial species is growing on its own, it is called a what?
planktonic growth
single species of bacteria can form a single species biofilm. where would you expect to find these biofilms in a medical environment
catheters and cannulas
when there is a multi species biofilm, this would be referred to as what?
plaque
mutans
salivarius
anginosus
oral mitis
are 4 main groups of which bacteria
oral streptococci
oral streptococci are both faculative and obligate anaerobes, why is this.
the conditions in the oral cavity or constantly changing and this may result in the species to change
which of the 4 main groups of oral streptococci are known for denal caries
mutans
salivarius
anginosus
oral mitis
mutans
produce lactic acid
how do the streptococci mutans produce energy
they have intracellular storage of carbohydrates, which they can break down to produce energy
streptococci mutans can produce ATP with or without oxygen this must mean it is a ……….. anaerobe
faculative
how do streptococci mutans produce lactic acid
they ferment carbohydrate to produce lactic acid at a high rate
Streptococci mutans can tolerate high concentrations of acid known as
aciduric
what on the S. Mutans attaches to the dental pellicle this allows attachment of S. mutans to the surface of the tooth.
the protein antigens I/II
Once S. mutans been attached, it needs to give itself stability. And it does this by the production of what?
glucosyltransferase (GTF). GTF is responsible for the biosynthesis of extracellular polysaccharides.
what do extracellular polysaccharides act as
a molecular glue, allowing the bacterial cells to adhere to each other as well as surfaces.
After streptococci mutans, lactobacilli are the most important group of bacteria involved in dental caries
is lactobacilli a gram +ve or -ve
Lactobacilli are gram +ve (thicker peptidoglycan layer and no outer lipid membrane)
if something does not sporulate, what do they not do
produce spores
lactobacilli does not sporulate
is lactobacilli a obligate or faculative anareobe
faculative
lactobacilli can survive and reproduce under acid conditions pH 5.5, this must mean that it is both what
acidogenic - acid forming
aciduric
Lactobacilli has poor adhesion properties, would you expect it to be a early or late coloniser
late coloniser
Lactobacilli adheres to dentine, which is over represented in advanced carious lesions.
what features does dentine have that allow adhesion
dentinal matrix
Streptococci mutans is associated with as early colonisers, due to their antigen protein attaching to the dental pellicle.
As the caries development makes its way to the dentine, there is a decrease in enamel pellicle
what happens to the numbers of streptococci mutans.
Lactobacilli tend to increase as streptococci mutans fall
the correlation between numbers of lactobacilli and carious lesions would be positive/negative
positive
is actinomyces a gram +ve or -ve
Are a gram +ve pleomorphic rods
actinomyces is a gram +ve pleomorphic rod, what is the feature of pleomorphic rods
microorganisms’ ability to alter their shapes or size in response to environmental conditions
actinomyces growth as branched hyphae, what is hyphae
like the mycelium of a fungus, but do not produce spores
why would you expect to see an Increase in actinomyces with the progression of periodontal disease.
actinomyces is associated with supra and subgingival plaque. as the progression of periodontal disease occurs, more space is avilable for the accumulation of actinomyces
For caries to occur the following what must be present
teeth,
plaque bacteria,
sugar
and time.
a substance released by one bacteria that kills another usually by inducing a metabolic block, is known as as a what
bacteriocin
Plaque communities can be broken down to two groups, what are they
supra-gingival and sub-gingival
why do Oxygen levels vary in the mouth
they vary because of the mouth being closed during sleep. Which limits the oxygen in the mouth
would you expect faculative or obligate anareobes to dominate supra-gingival plaque
faculative
which plaque community would be exposed to a lack of oxygen
sub-gingival
which plaque community would be exposed to constant conditions
sub-gingival
which plaque community would be exposed to dietary carbohydrates
supra-gingival
which plaque community would have obligate anaerobes
sub-gingival
which plaque community would get proteins derived from serum
sub-gingival
which plaque community would be present in gingival crevicular fluid
sub-gingival
which plaque community would have abundance of gram-ve
sub-gingival
a plaque score of 0 indicates what
no plaque in gingival area
a plaque score of 1 indicates what
thin film of plaque (detected with probe)
a plaque score of 2 indicates what
moderate amounts of plaque (seen with eye)
a plaque score of 3 indicates what
gross deposits on the tooth
a plaque score of 2 (moderate amounts of plaque seen with eye) is usually achieved after how many days of OH neglect
10 days of OH neglect
a gingival index is used to measure the gingival findings.
a gingival score of 0 indicates what
healthy gingiva
a gingival index is used to measure the gingival findings.
a gingival score of 1 indicates what
mild inflammation (slight colour changes, no BOP)
a gingival index is used to measure the gingival findings.
a gingival score of 2 indicates what
moderate inflammation (redness, odema, BOP)
a gingival index is used to measure the gingival findings.
a gingival score of 3 indicates what
Severe inflammation. (redness, oedema, ulceration, spontaneous bleeding)
- Children: accumulate large amounts of plaque and show little gingival inflammation
- Whereas the elderly show severe inflammation associated with small amounts of plaque.
what does this suggest
- This suggests that susceptibility to plaque increase with age.
Chronic periodontitis follows gingivitis, how many teeth must be affected to reach the periodontitis title
>10 of 32 teeth
>30%
what pockets are shown during gingivitis
false pockets
what pockets develop during periodontitis
true pockets
what causes the reasorption of the bone in periodontal disease
osteoclast are activated during periodontitis, this results in the reabsorption if the bone.
Aggressive periodontitis follows from periodontitis
the bacteria that comprise of 70% of the flora is what
A. actinomycetemcomitans
- Is a oral species found in the gingival sulcus and periodontal pockets.
- Gram -ve, often found associated with Actinomyces
- Adhesion: has fibrils & fimbriae which help bind on to the ECM.
is describing what pathogen
Aggregatibacter actinomycetemcomitans
red complex & exclusively found in gingival sulcus & periodontal pocket. best describes which pathogen
porphyromonas
a mass of cells and fluid that has seeped out of blood vessels or an organ, especially in inflammation is known as
exudate
Gingival crevicular fluid is an example of what
exudate
The process of disease changes the GCF, components that increase the GCF are:
- PMNs
- Cytokines
- K levels increase
- Haem
- Nitrate
- Enzymes secreted or released through lysis can benefit another species
- Metabolic products can be beneficial to other species
- Adhesion to other species or cell products
- Gene transfer, mutation and new genes, causing genetic variation
these interactions are known as what interactions
synergistic interactions
there are different types of adhesion seen in dental plaque.
how would you describe cell-substratum adhesion
the first cells to adhere to the dental plaque.
example would be the protein antigen adhering to the pellicle
there are different types of adhesion seen in dental plaque.
how would you describe homotypic cell - cell adhesion
The attachment of a cell to a second cell of the identical type via adhesion molecules
there are different types of adhesion seen in dental plaque.
how would you describe heterotypic cell - cell adhesion
The attachment of a cell to a cell of a different type via adhesion molecules
corn cob complexes and test tube brush complexes is an example of what type of adhesion adhesion
heterotypic cell-cell adhesion
