THE IMMUNE SYSTEM

 The system that does not contain a

prominent organ.

THE OVERVIEW OF THE IMMUNE SYSTEM

Immune System

Lymphatic
Body Defenses
System

Nonspecific Specific Body Lymphatic

Body Defenses Defenses Vessels
(Innate) (Adaptive)

Lymphoid
External Internal Humoral Cell-Mediated Tissues and
Immunity Immunity Organs

Surface Mucus
Membrane WBC Inflammation
Membranes
Barriers

Complement Fever
proteins and
Cytokines
THE LYMPHATIC SYSTEM PRODUCES AND
TRANSPORTS MANY IMMUNE SYSTEM
CELLS
LYMPHOID ORGANS

LYMPHATIC SYSTEM
 Plays a crucial
role in the immune
system.
 The vessels of the
lymphatic system
collect and
distribute a fluid
called LYMPH.

LYMPHATIC VESSELS

LYMPH NODES
 pH level (slightly acidic)
LYMPHATIC TISSUES  The acidic mantle of the skin is the result
of the mixture of sebum(fatty acid) and
sweat (lactic acid and amino acids).

Melanin
 The pigment that absorbs ultraviolet (UV)
radiation protecting us from some types of
skin cancers.

MUCOUS MEMBRANE

THE BODY DEFENSES: THE (INNATE)

NONSPECIFIC BODY DEFENSES

THE (INNATE) NONSPECIFIC BODY

DEFENSES
 Innate refers to the fact that these
defenses are always present and ready to
function.
 This type of defense provide a broad
defense against any infectious agent.

How broad is the body’s innate defense?

SURFACE MEMBRANE

WHITE BLOOD CELLS

Stratified Squamous Epithelial Cells

 The epidermis is composed of layers of
cells which act as a physical barrier
against pathogens.
 The upper layers are composed of dead
skin cells.  consumes bacteria via phagocytosis
 secretes substances that destroy
Keratin pathogens
 Anchors the cells together to form the
outer layer of the skin forming a barrier.
Basophils

 provoke inflammation, attracting

additional white blood cells.

Natural Killer Cells

COMPLEMENT PROTEINS AND

CYTOKINESIS
Complementary Cytokinesis
Proteins
 destroys cancerous or virus-infected cells.

Macrophages and other phagocytes

Helps destroy Messenger proteins

pathogens in the body. that bind to immune
cells and promote
Some trigger a chain cell division, activate
reaction that punctures defenses or alter
bacterial cell their activity.
 consume pathogens and promote fever. membrane.

Inflammation
 Is an immediate, localized reaction to an
injury or any pathogen that breaches the
body’s barriers.
 Signs and Symptoms:
o Area surrounding the wound or
infection becomes:
 Red
 Warm
 Swollen
 Painful
 Over-all, this nonspecific defense recruits Fever
immune system cells, helps clear debris,  Fever is a common reaction to infection
and creates an environment hostile to  Mild fever can help fight infection by:
microorganism. o Inhibiting bacteria and viruses
o Counters microbial growth
o Phagocytes attack
INFLAMMATORY RESPONSE
Cytokines
 Cytokines travel throughout the body in
the bloodstream.
 At the hypothalamus, they can trigger a
temporary increase in the set point of the
body’s thermostat.
THE BODY DEFENSES: THE (ADAPTIVE Memory cells Plasma cells
IMMUNITY) SPECIFIC BODY DEFENSES Remembers the Clones of the original
exposure to the B cells.
antigen for years or
decades. Secretes huge
amount of antibodies
at the rate of
thousand molecules
per second.

 Humoral Immunity is active or passive.

Active immunity Passive immunity

THE (ADAPTIVE IMMUNITY) SPECIFIC BODY Results from the Person receives
DEFENSES body’s own intact antibodies from
 Adaptive immune response, on the other production of another individual.
hand, act against individual targets. antibodies after
 Two classes of lymphocytes, B cells and exposure to antigens Temporary
T cells, provide the ammunition in these in the environment.
precision defenses. Can be natural or
 The target in an adaptive immune Memory cells are artificial
response is an antigen, which is any produced.
molecule that stimulates an immune
reaction by B and T cells. can be natural or
 Antigen (short for antibody- generating) artificial
stimulates the production of these Y-
shaped proteins that recognize specific The Secondary Immune Response is stronger
antigens. than the Primary Response

Primary response Secondary response

Helper T-Cells Is the adaptive Immune system’s
 “Master cells” reaction to a foreign reaction the next time
 initiate and coordinate the adaptive antigen it detects the same
immune response. foreign antigen
Could take days or
CELL-MEDIATED IMMUNITY weeks to reach its Much more
Cytotoxic T-Cells provide Cell-mediated peak aggressive/stronger
Immunity than the primary
 binds to and destroys “suspicious” cells- response
that are cancerous, damaged, foreign to
the body, or infected with viruses or Activated within hours
bacteria. and produce billions
 Activation of the cell-mediated immunity of antibodies
requires a cytotoxic T-cell to bind to a cell
showing an antigen in its cell membrane. VACCINES
 An activated T-cell differentiate into  Jumpstarts immunity
memory cytotoxic T-cells and effector  Substance that stimulate active immunity
cytotoxic T-cells. against a pathogen without actually
causing illness.
HUMORAL IMMUNITY  Vaccines consist of antigen
B cells direct the Humoral Immune Response
 History of vaccine use:
 The humoral response includes millions
of different B cells, each producing a  18th century
unique antibody.  Edward Jenner (Physician) used cowpox
 Antibodies are defensive proteins to cure smallpox
o Large proteins that circulate freely  Smallpox was declared eradicated in the
in blood plasma, lymph, and 1980’s by the World Health Organization
interstitial fluid (WHO)
o Simplest antibody molecule
consists of four polypeptide SEVERAL DISORDERS THAT AFFECT THE
forming Y shape. IMMUNE SYSTEM
o binds to an invader antigen and
-Autoimmune Disorders
neutralize the pathogen in several
ways.  Occurs when the immune system
 Activated B cells produce a surge of produces antibodies that attack the
identical antibodies, this is called clonal body’s own tissues.
selection.
  Medical microbiology, the large subset of
microbiology that is applied to medicine,
is a branch of medical science concerned
with the prevention, diagnosis and
treatment of infectious diseases.
 In addition, this field of science studies
various clinical applications of microbes
for the improvement of health.
 There are four kinds of microorganisms
that cause infectious disease:
o bacteria,
o fungi,
-Human Immunodeficiency Virus (HIV)
o parasites and
 kills helper T-cells, causing AIDS
o viruses, and
 ACUTE STAGE-Flu-like symptoms can
 one type of infectious protein called prion.
include:
o Fever
MICROBIOLOGY
o Chills
 A specialized area of biology that deals
o Rash
with living things ordinarily too small to be
o Night sweats
seen without the microscope.
o Muscle aches
 Such microscopic organisms are
o Sore throat collectively called as
o Fatigue MICROORGANISMS.
o Swollen lymph nodes
o Mouth ulcers Lay terms:
 LATENCY STAGE  Microbes
 STAGE 3-Symptoms of AIDS can include:  Germs
o Rapid weight loss  Bugs
o Recurring fever or profuse night
sweats CLASSIFICATION (TYPES OF CELLS
o Extreme and unexplained ACCORDING TO STRUCTURE):
tiredness
o Prolonged swelling of the lymph
glands in the armpits, groin, or
neck
o Diarrhea that lasts for more than a
week
o Sores of the mouth, anus, or
genitals
o Pneumonia
o Red, brown, pink, or purplish
blotches on or under the skin or
inside the mouth, nose, or eyelids
o Memory loss, depression, and
other neurologic disorders

-Severe Combined Immunodeficiency (SCID)

 Inherited
 Adaptive
immune
response is
defective Prokaryotic cells Eukaryotic cells
very minute in size (1- Larger in size (10-
-Results from intake of drugs that prevent organ 10μm) 100μm)
rejection.
single chromosome Nucleus is
-Results from intake of drugs that suppress the present surrounded by a
double membrane
immune system against autoimmune disorders. Nucleolus is absent layer
Membrane bound more than one
INTRODUCTION TO MICROBIOLOGY organelles are absent chromosome is
 present
multiplication of cell is
by fission or budding membrane bound
organelles are
chemically complex present
chemcals are present cell division is by
mitosis or meiosis
Ex. bacteria, archea
cell walls seen in only
plant cells, which are
chemically simpler

usually multicellular BACTERIAL CELL STRUCTURE:

PROTECTIVE LAYERS
Ex. animal cells and
plant cells CELL WALL
 a structure external to the plasma
membrane
 Cell walls for prokaryotes are made of
PEPTIDOGLYCAN
 Fungal and protistan cell also have cell
walls
 External structure: protection against low
osmotic pressure, rigidity and shape
 Function:
MAJOR COMPONENTS OF THE CELL o Rigid covering
o Structural support and gives shape
of the cell

PROTECTION
 The parts that separates each cell from its Subcellular organelles: Cell wall
surroundings
o Plasma membrane
o Cell wall
o Glycocalyx

PLASMA MEMBRANE
 A thin barrierthat
forms a boundary
separating an
individual cell from Gram positive Gram negative
the external
environment. Bacteria that give a Cannot retain the
 Keywords: Semi- positive result in the violet stain after the
permeable Gram stain test. decolorization step
membrane
Takes up the crystal
 Function: violet stain used in the
o Encloses the cell content test and then appear
o Provides shape (animal cells) to be purple coloured
o Allows transport of certain when seen through a
substances in and out of the cell. microscope.
GLYCOCALYX o Chloroplasts and
 A slimy, gelatinous material produced by o Mitochondria
the cell membrane and secreted outside
of the cell wall SUBCELLULAR ORGANELLES
 Two types: Slime layer, Capsule
o Slime layer Nucleus
 Not highly organized; not  It is the storage house of genetic
firmly attached to the cell information: DNA
wall.  Found only in EUKARYOTES
 Easily detaches from cell
wall and drifts away.
 Example:
Pseudomonas
species
o Capsule
 Highly organized; firmly
attached to the cell wall.
 Consists of
polysaccharides, which is
Nuclear Envelope
combined with lipids and
 membrane enclosing the
proteins.
nucleus.
 protects against
 NUCLEAR PORES
phagocytosis.
o these protein-
lined pores
allowmaterials (ions, molecules,
and mRNA) to move in and out of
the nucleus.

Chromatin
 these are DNA with
THE WORKING SPACE associated proteins
attached to it.
 the area where most of the action takes
place.  CHROMOSOMES
o Cytoplasm o (DNA without
proteins)
CYTOPLASM o only visible and distinguishable
 It is the space between from chromatin when the cell is
the nucleus and the cell getting ready to divide.
membrane.
Nucleolus
 70 to 80% H2O
 it is a condensed
 Semi-solid in
region where
consistency
ribosomes are
 Contains glucose (mono
formed.
& polysaccharides), amino acids, nucleic
acids, fatty acids, glycerol derivatives,
Na+, K+, and Ca+
MANUFACTURING SECTION
 Ribosomes
GENETIC CONTROL CENTER
 Endoplasmic Reticulum
 Brains of the cell
o DNA
RIBOSOMES
o Nucleus
 are found in:
o PROKARYOTES and
DNA
EUKARYOTES
 Deoxyribonucleic
o cytoplasm in PROKARYOTES
Acid
o Endoplasmic Reticulum,
 The genetic material
Mitochondria and Chloroplasts for
found in all types of
EUKARYOTES.
cells.
 Found in other
organelles:
  the pantry and
breakdown
compartments of the
cell.
 Found only in
eukaryotes
 membrane bound sacs that functions in
storage and transport
 Function:  they can fuse with other membranes
o responsible in protein synthesis except for VACUOLES
(the manufacture of proteins).
o >>abundant in cells that produce a VACUOLES
lot of proteins like enzymes.  found only in eukaryotes
 It usually provides supporting roles in
ENDOPLASMIC RETICULUM (ER) animal cells
 Series of  Act as support for plants
interconnected  In plants, it
membrane sacs contains toxins
and tubules that for protection
collectively  Storage of
modify proteins harmful waste
and synthesizes products and
(creates) lipids. pigments
 Rough Endoplasmic Reticulum  In mature plant
o with RIBOSOMES cells, the large central vacuole serves as
o place where newly synthesized its lysosomes
proteins (CHON) are modified such
as folding or acquisition of side LYSOSOMES
chains.  Round shaped
 Smooth Endoplasmic Reticulum  Contains
o WITHOUT ribosomes chemicals
o continuous with RER (enzymes) to
o synthesizes glucose (CHO), lipids, breakdown
steroid hormones materials in the
o Detoxification of medications & cell
poisons  Tends to be
o storage of Ca+ ions fewer or absent in plants
 Function:
THE DISTRIBUTION CENTER o Breaks down worn out cell or
 Golgi apparatus debris
o Performs digestion for food
GOLGI APPARATUS (BODY) particles or captured bacteria
 found only in o Ex. Macrophages (a blood cell)
EUKARYOTES
 has two sides: PEROXISOMES
o cis-receiving  found only in
side EUKARYOTES
o trans-opposite  Originates in the
side endoplasmic
reticulum
 Function:
o sorting,  Function:
o detoxify
packaging, tagging (in the lumen),
and distribution. poisons
STORAGE AND DIGESTIVE CENTERS inside the vesicle
o breaks down fatty acids
 Vesicles
o produces cholesterol and other
 Vacuoles
lipids
 Lysosomes
 Peroxisomes
ENERGY-PROCESSING CENTERS
 where cells get the needed energy to live
VESICLES
o Mitochondria
 o Chloroplasts
INTERMEDIATE FILAMENTS
MITOCHONDRIA  fibrous CHON that hold organelle in place
 found only in  Function:
EUKARYOTES o Structural support: resist
 it has its own mechanical stress
DNA and
ribosomes SUBCELLULAR ORGANELLES: CELL
 it membrane EXTENSIONS
bound
 abundant in muscle cells CILIA
 it utilizes oxygen (O2) to produce ATP and  little hairs
generates carbon dioxide (CO2) as waste  moves in
product coordinated
 Function: fashion for mobile
 Produces energy in cells (unicellular
the form of organisms)
Adenosine  produces
Triphosphate sweeping motion for anchored cells
(ATP), a short term (usually in multicellular organisms)
stored energy
FLAGELLA
CHLOROPLASTS  moves in
 found in EUKARYOTES (PLANTS only) WHIP-LIKE
 contains chlorophyll (the green pigment motion for
that captures light energy) single-celled
organisms
SUPPORT STRUCTURES  threadlike, protein
 the scaffoldings within the cell appendages
o Microtubule  organ of
o Centrosome locomotion
o Microfilaments  12-30 nm
o Intermediate filaments
FIMBRIAE AND PILI
MICROTUBULE  Rigid surface
 Form the appendages
mitotic  common
spindle and among gram
maintain cell negative
shape. bacteria
 shorter and finer than flagella
CENTROSOME  made of protein(pillus)
 microtubule  for adherence/not for motility
organizing  for conjugation and transfer of genetic
center material (sex pili)
 in ANIMAL
CELLS, it SPECIAL STRUCTURES: ENDOSPORES
contains
centrioles ENDOSPORES
(barrel-like structure) which are  Resting cell
perpendicular with each other  highly resistant to desiccation
 common among Bacillus(aerobic) and
MICROFILAMENTS Clostridium (anaerobic)
 fibrous CHON form the
cellular cortex CLASSIFICATION OF ENDOSPORES
 it is powered by ATP ACCORDING TO LOCATION
during cellular events  TERMINAL- Clostridium tetani
that require motion  CENTRAL- Clostridium botulinum
 Function:  SUBTERMINAL- C. sporegenes
o Responsible for
the gross movement of the cell
  True Pathogen
o Can cause infection to people with
normal immune system and much
more if immunocompromised.
 Opportunistic
o cause infection to
immunocompromise host.
 Microorganisms (pathogens) cause two
categories of diseases:
o Infectious disease
o Microbial intoxication
 Occurs from eating a food
that contains a toxin
produced by bacteria.

CYTOPLASMIC Nosocomial Infection

GRANULES  results of
 food deposits treatment in a
 Much- hospital or
Mycobacteria hospital-like
 Babes-ernst- C. setting, but
diptheriae secondary to the
patient's original condition.

BASIC TERMINOLOGIES IN MICROBIOLOGY Endogenous Infections

 produced or growing
Infection from within
 The invasion and  is a disease caused
multiplication of by an infectious agent
microorganisms that is already
and parasitic present on or in the
organism within the host but previously asymptomatic or
body. dormant.
 The agent may be from the same genus
or species as the one that causes disease
Infestation in other people. An endogenous infection
 The growth of a may occur when the host’s defenses are
parasitic organism weakened or breached.
outside the body.
Exogenous Infections
 Derived or developed
from outside the
Infectious Disease body.
 a disease caused  is an infection caused
by the entrance by a microorganism
into the body of that is acquired from
pathogenic agents the environment
or microorganisms (e.g., from soil or water) or from another
(such as bacteria, person or an animal.
viruses,
protozoans, or fungi) which grow and
multiply there Host
 These diseases can be spread from  an organism
person to person either directly (e.g., via that harbors
skin contact) or indirectly (e.g., via a virus,
contaminated food or water) parasite,
mutual
Pathogen partner, or
 An agent of disease. commensal
 A disease producer partner,
 “Microbial Enemies”
 typically providing nourishment and
shelter.

Carrier
 is someone who is
capable of
transmitting a
disease (especially
an infectious or
genetic disorder) to
another person but who usually has no
symptoms of the disease.

Reservoir Direct Contact

 source/extension  Refers to
of the infection. person-to-
 an alternate or person spread
passive host or of
carrier that microorganisms
harbors through actual physical contact.
pathogenic
organisms without Indirect Contact
injury to itself and serves as a source  Touching an object that an infected
from which other individuals can be person has touched.
infected.
 It is the habitat of an infectious agent.

ROUTE OF ENTRY FOR MICROBES

METHODS OF TRANSMISSION:
Airborne contact
Congenital Contact
 via placenta
 through mother to offspring (still in the
womb)

Ingestion (Food borne)

 get from something they ate or drank. The
causes are germs or other harmful things
in the food or beverage.

Sexual Contact
 It is part of direct contact

Vector Borne
  Transmitted through a vector, insects, or  the mechanical removal, rather than
animals. killing of microbes in a limited area.

Sanitization
 The intention of
lowering the
microbial count to
a safe public
health levels
 Minimizes the
Iatrogenic Infections disease transmission.
 caused by medical treatment; it usually
results from a mistake made in diagnosis NAMES OF TREATMENT OF MICROBES
or treatment and can also be the fault of
any member of the healthcare team. Suffix-cide
 Kills the microbes
 biocide, germicide, fungicide, virucide
MICROBIAL CONTROL AND STERILIZATION
Suffix-stat or stasis
THE TERMINOLOGY OF MICROBIAL  Inhibits the growth and multiplication
CONTROL  Bacteriostasis

Sterilization THE RATE OF MICROBIAL DEATH

 removal or  When bacterial
destruction of populations are
“all” living heated or treated
microorganisms with antimicrobial
 Method: heating chemicals, they
(solid), filtration usually die at a
(liquids or constant rate.
gases)  For example, suppose a population of 1
 A sterilizing agent is called sterilant. million microbes has been treated for 1
minute, and 90% of the population has
Disinfection died.
 control directed
at destroying SEVERAL FACTORS INFLUENCING THE
harmful EFFECTIVENESS OF MICROBIAL
microorganisms TREATMENTS
 Disinfection  The number of microbes
might make use  Environmental influences
of chemicals,  Nature of surface to be disinfected
ultraviolet radiation, boiling water, or  Time of exposure
steam  Biofilms
 In clinical practice: chemical treatment on  Compatibility of Disinfectants
an inert surface or substance.  Microbial characteristics

Antisepsis The number of microbes

 Directed  The more microbes
towards there are to begin
treatment on a with, the longer it
living tissue takes to eliminate
(antiseptic) the entire
 Sepsis – population.
indicates bacterial contamination.
 Aseptic – means the area is free from
pathogens.
 Asepsis – the absence of contamination. Environmental
influences

Degerming
  Most disinfectants work somewhat better  Ex: the use of bleach and quaternary
in warm solutions. ammonium compound together may
negate the activity of both disinfectants.
Nature of surface to be disinfected
 Certain medical ACTIONS OF MICROBIAL CONTROL
instruments are AGENTS
manufactured of
bio materials that Alteration of Membrane Permeability
exclude the use  Cell membrane is the target of many
of certain antimicrobial agents.
disinfection or  Damage to the lipids or proteins of the
sterilization methods because of possible plasma Pmembrane by antimicrobial
damage to the instruments. agents causes cellular contents to leak
into the surrounding medium and
Time of exposure interferes with the growth of the cell.
 The contact time
is a function not Damage to Proteins and Nucleic Acids
only of the agent  Bacteria are sometimes thought of as
itself but also of “little bags of enzymes.” Enzymes, which
the bio-burden of are primarily protein, are vital to all
the object, the cellular activities.
type of  Peptide bonds could be damaged or
microorganisms reshaped by heat and chemicals.
to be killedand the presence of organic  DNA, when damaged by heat, UV rays, or
material and the temperature at which the chemicals causes the microbial cell to die
agent is being used. or lose its ability to replicate.
 Chemical antimicrobials often require
extended exposure to affect more- PHYSICAL METHODS OF MICROBIAL
resistant microbes or endospores. CONTROL
 Compare the effectiveness of moist heat
Biofilms (boiling, autoclaving, pasteurization) and
 Community of dry heat.
bacteria and  Describe how filtration, low temperatures,
other high pressure, desiccation, and osmotic
organisms pressure suppress microbial growth.
 Microbes in  Explain how radiation kills cells.
surface
biofilms, when HEAT
they are
encased in the mucoid matrix are difficult 1. Moist Heat (Steam under pressure)
for biocides to reach effectively.  Autoclaving (essentially a large pressure
cooker)
Compatibility of disinfectant o Most effective method for:
 A common Culture media, Specimen,
mistake is to Instruments
believe that o Principle: Steam under pressure
two 121 degree C @ 15 lbs. psi
disinfectants (pounds per square inch) @ 15
are better minutes
than one. o All microorganism (except prions)
 Some are destroyed in approximately 15
disinfectants minutes
may inactivate o Biological indicator: B.
the action of
steatothermophilus
another

disinfectant.
  Method of
choice for
antibiotic
solutions, toxic
chemicals,
radioisotopes,
vaccines, and
carbohydrates
which are toxic
sensitive.
 Accomplished
by pulling a
DRY HEAT solution into a
cellulose
1. Oven acetate or
 Temp: 160- cellulose nitrate
180C 1 1⁄2 - 2 membrane with a vacuum.
hours  Filtration of air is accomplished using
 Requires High Efficiency Particulate Air (HEPA)
longer filters designed to remove organisms
exposure time larger 0.3 um from isolation rooms,
(1.5 – 3 operating rooms, and biological safety
hours) and cabinets.
higher temperatures than moist heat.
 Used to sterilize items such as glassware,
oil, petrolatum, or powders.
 Biologic indicator: Bacillus. subtilis var.
niger.

2. Incineration
 Most common PHYSICAL METHODS
method of  Boiling
treating o at 100 degree C for 15 minutes
infectious waste. which kills vegetative bacteria
 Hazardous o destroy almost all microorganisms
materials is in HIGH temp
literally burned to
ashes.  Pasteurization
 Temp: 870 – 980C o Destroy almost all organism in
 Toxic air emissions and the presence of LOW temp
heavy metals in ash have limited the use o 63 degree C for 30 minutes or 72
of incineration in most large cities in the degree C for 15
US. seconds, which kills
food pathogens
3. Flaming  For milk and Dairy products
 using an (pathogens)
alcohol lamp  BATCH
or a burner METHOD/LOW
 For TEMP. HOLDING
disinfection of  63 degree Celsius for
wire loops and 30 minutes
needles under  FLASH
a red-hot METHOD/HIGHT
flame. TEMP. SHORT TIME
 72 degree Celsius for
15 minutes
4. Ionizing radiation  Mercury Lamps
 For sterilization of disposables such as
plastic syringes, catheters, or gloves CHEMICAL
before use. METHODS OF
MICROBIAL
FILTRATION CONTROL
 o Algicide
1. Alcohol  Silver nitrate
 ethyl and isopropyl (two most common o 1% eyedrop solution as
used chemical antiseptic). prophylaxis to prevent ophthalmia
 Required concentration of alcohol 60-70% neonatorum in newborns.
 Inactivate microorganisms by denaturing
CHONs. 6. Quaternary Ammonium Chloride
 Used principally as antiseptic.  Example: Benzalkonium Chloride
 Bactericidal, pseudomonacidal, and (Zephiran)
fungicidal in 10 minutes exposure  Inactivated by: Organic compounds
 Tuberocidal and virucidal (except  Disadvantages: Non-sporicidal; Non-
hydrophilic viruses) in 15 minutes tuberculoidal.
exposure.
 70-90 % Isopropyl alcohol – effective 7. Phenolics (Standard disinfectant)
against Hepatitis B Virus.  Fairly broad spectrum of activity but not
sporicidal.
2. Aldehydes  Stable, biodegradable and relatively
 Formalin – often used to disinfect active in the presence of organic
biosafety hoods materials.
o Irritable and carcinogenic  Mechanism: Disruption of the cell wall
o Mycobacterium – survived in resulting in the precipitation of proteins.
tissues fixed with formaldehyde.  Main use: Disinfection of Hospital,
 Glutaraldehyde – has broad spectrum institutional, and household
activity and rapid killing actions. environments.
o Extremely susceptible to pH  Phenol Coefficient
changes o Expression of bactericidal property
 Germicidal in approximately 10 minutes of a disinfectant as compared to
and sporicidal in 3-10 hours at 2% pure phenol.
solution o PC = highest dilution of
o Inactivates DNA and RNA disinfectant that would kill
 Virucidal (against HIV and HBV) in 10 organism at a given time/highest
minutes at 20 – 30 degree Celsius. dilution of phenl that will kill
organism at a given time.
3. Iodophores o Control organism: S.aureus;
 Iodine can be a disinfectant in one of two S.typhi
forms:  PC>1 = Disinfectant better
o Tincture – alcohol and iodine  PC<1 = Phenol is better
solutions (antiseptic)  PC = 1 Same Efficiency
o Iodophore – iodine and neutral
polymer carrier (as antiseptic or 8. Ethylene oxide (EtO)
disinfectant)  most common chemical sterilant which is
 Povidone Iodine used in gaseous form for sterilizing heat
 Contact time of iodophore in skin – 30 sensitive objects.
seconds.  Formaldehyde vapor & vapor phase
H2O2
4. Chlorine and Chlorine compounds o (an oxidizing agents) have been
 Oldest and most commonly used used to sterilize HEPA filters in
disinfectants BSCs
 Usually used in the form of hypochlorite  Glutaraldehyde – Sporicidal (kills spore)
 Na Hypochlorite (household bleach) o in 3-10 hours, is used to sterilize
 Killing activity is based on the oxidative equipment such as
effect of hypochlorous acid formed when bronchoscopes, because it does
chloride ions are dissolved in water. not corrode lenses, metal or
rubber.
5. Heavy Metals  Peracetic acid
 Rarely used in the clinical setting o Effective in the presence of organic
 Bacteriostatic materials has been used for
 Mercury (Hg) surface sterilization of surgical
o ingredient in Merthiolate instruments.
 Copper (Cu)
MICROBIAL GROWTH  Molds and yeast’s optimal pH is about pH
 Increase in number of cells, not cell size. 5 to 6.
 One cell becomes a colony of millions of  Many bacteria and viruses survive low pH
cells. of stomach to infect intestines.
 Control of growth is important for infection o Helicobacter pylori lives in stomach
control, and growth of industrial and under mucus layer.
biotech organisms.
OSMOTIC PRESSURE
PHYSICAL REQUIREMENTS FOR  Microbes obtain almost all their nutrients
MICROBIAL GROWTH in solution from surrounding water.
 Temperature  Tonicity – measures the osmotic pressure
 pH gradient between two solutions separated
 osmotic pressure by the cell membrane.

TEMPERATURE

 Hypotonic
Minimum Growth the lowest o Some bacteria may lyse in these
temperature temperature at which conditions because of their weak
the species will cell wall.
grow.
 Hypertonic
Optimum Growth the temperature at
temperature which the species o Causes the bacterial cell to loose
grows best. water in a condition called
Maximum Growth the highest “plasmolysis”.
temperature temperature at which
growth is
possible.

 Organisms that can survive higher salt

concentrations are called “halophiles”.
 Extreme halophiles
o Aka obligate halophiles survive in
30% salt solution.
 Facultative halophiles
o Survives at 2%

THE CHEMICAL REQUIREMENTS FOR

MICROBIAL GROWTH
Chemical Description
Water/H2O The first most
important for microbial
growth
Carbon The second most
important for microbial
pH growth
 Most bacteria grow between pH 6.5 - pH Nitrogen, Sulfur, and Needed by
7.5. Phosphorus microorganisms to
 Very few can grow at below pH 4.0 synthesize organic
materials like DNA,
 Acidophiles are select few bacteria that RNA, ATP, amino
can survive at a pH 1. groups, and
ammonium ions.
 tolerate it fairly well. oxygen but grow only
Cyanobacteria- in low oxygen
nitrogen fixation Ex: Lactobacilli concentration than
those in air.
Sulfur is synthesized
into sulfur-containing
THE EFFECT OF OXYGEN ON THE GROWTH
amino acids and
OF VARIOUS TYPES OF BACTERIA
vitamins such as
thiamine and biotin
Trace elements Iron, copper,
molybdenum, and
zinc

Essential for enzymes

as cofactors
Oxygen Oxygen is actually a
poisonous gas

Organism free
hydrogen atoms from
organic compounds to
bond it with oxygen to
form water

MICROORGANISMS ACCORDING TO THEIR

OXYGEN REQUIREMENTS

Obligate Facultative Obligate

aerobes anaerobes anaerobes
Require Can utilize Unable to use
oxygen to oxygen but oxygen and
live. has the ability most are
to grow in the harmed by its
absence of presence.
oxygen.
Ex:
Ex: E. Coli, Clostridium
many yeast

Aerotolerant Microaerophiles
anaerobes
Cannot use oxygen They are aerobic;
for growth but they they do require

UNDERSTANDING HOW ORGANISMS CAN BE HARMED BY OXYGEN REQUIRES A BRIEF

DISCUSSION OF THE TOXIC FORMS OF OXYGEN
PHASES OF GROWTH  Death rate > rate of reproduction
 Due to limiting factors in the environment
LAG PHASE
 Bacteria are first
introduced into an
environment or
media
 Bacteria are
“checking out” their
surroundings
 Cells are very
active metabolically CULTURE MEDIA
 Number of cells changes very little Definition of Terms
 1 hour to several days
Culture medium
LOG PHASE  A nutrient material prepared for the
 Rapid cell growth growth of microorganisms in a laboratory.
(exponential growth)
Inoculum
 Population doubles
every generation  Microbes that are introduced into a
culture medium to initiate growth
 Microbes are
sensitive to adverse
Culture
conditions
o Antibiotics  The microbes that grow and multiply in or
on a culture medium
o Anti-microbial agents

TYPES OF MEDIA
STATIONARY PHASE
 Death rate = rate of
CHEMICALLY DEFINED MEDIA
reproduction
 One whose exact chemical composition is
 cells begin to
known
encounter
 Used for microorganism that require
environmental stress
many factor (described as fastidious)
o lack of
nutrients
COMPLEX MEDIA
o lack of water
 Reserved for lab experiment work
o not enough
 Most heterotrophic bacteria and fungi are
space
routinely grown on this
o metabolic wastes
o oxygen SPECIAL CULTURE TECHNIQUES:
o pH ANAEROBIC BACTERIA
 Reducing media
DEATH PHASE  Anaerobic container
 Agar stab
 Agar shake
 o pH indicator (turns yellow when
acid)
 Ex.: MacConkey’s Agar
o Used to
identify
salmonella
o Bile salts and
CULTIVATION crystal violet
 No artificial (inhibits gram (+) bacteria)
media/tissue culture o Lactose
available o pH indicator
 Mouse:
o Intradermaly ENUMERATION OF BACTERIA
inoculated into Bacteria enumeration is the process of
foot pads and determining the number of bacterial cells in a
develop local given sample. The counting of bacterial cells has
granulomatous lesions with limited four categories based on the purpose of the
multiplication of bacilli experiment: direct, indirect, viable, and total cell
o Inoculated armadillos develop count. Enumeration is done to assess the levels
extensive lepromatous leprosy of microbial contamination in raw material or
manufactured products, such as medicine. It is
SPECIAL CULTURE TECHNIQUES: also done to evaluate the effects of antimicrobial
MICROAEROPHILIC BACTERIA agents or the decontamination processes.
 Grow best under reduced oxygen levels
and increased carbon dioxide levels ENUMERATION OF BACTERIA: TURBID
 Normal atmosphere 21% oxygen and CULTURE
0.03 to 0.3% carbon dioxide

SPECIAL CULTURE TECHNIQUES:

SELECTIVE AND DIFFERENTIAL MEDIA
 Selective media are
designed to suppress
the growth of
unwanted bacteria and
encourage the growth
of the desired
microbes
 Ex.: Brilliant Green agar
o Dyes inhibited the
growth of gram
(+) bacteria
o Selects for gram (–) bacteria
o Most G.I. Tract infections are
caused by gram - bacteria
 Differential Media differentiates between
different organisms growing on the same
plant
 Ex.: Blood Agar Plates
o (TSA with 5%
sheep blood)
o Used to
differentiate
different types of streptococci
 Ex.: Mannitol Salt Agar
o Used to identify
staphylococcus
aureus
o High salt conc.
(7.5%) inhibits
most bacteria
o Sugar mannitol
 o Medium sized (4-8mm)
GRAM POSITIVE COCCI o Creamy, white or rarely gold
o Buttery
FAMILY MICROCOCCACEAE  Rare strains-fastidious
o Small colony variants grow on BAP
Saprophyte- feeds off on decomposed
 Staphylococci
materials like dead organisms, tissues, cells
o Common isolates
o causes supurative/pyogenic
1. Planococcus
infections
 free living saprophyte
STAPHYLOCOCCUS AUREUS
2. Micrococcus
 The most clinically significant species
 free living saprophyte
o Also an important cause of
 has the same morphological and cultural
nosocomial infections
characteristics as Staphylococcus and
 Gram positive cocci arranged in tetrads or
belong to the same family
clusters
Micrococcaceae.
 Facultative anaerobe
3. Stomatococcus  Medium sized, raised creamy colonies on
 normal flora on surface of primates and BAP or CNA with white, cream or golden
other mammals. yellow pigmentation
 Ubiquitous
4. Staphylococcus o found everywhere
 normal flora on surface of primates and
other mammals. VIRULENCE FACTORS (PATHOGENIC
DETERMINANTS) OF S. AUREUS
All, except planococcus have been isolated from SURFACE CHARACTERISTICS IN THE
clinically significant sources. ESTABLISHMENT AND COURSE OF
INFECTION
GENERAL CHARACTERISTICS
 catalase positive, gram (+) cocci Protein A
 resident flora of the skin and mucous  Bind to the antibody molecule, which
membranes and can be found throughout causes interference with phagocytosis
the environment and fixation of complement
 infections are directly or indirectly  Cell wall polysaccharides
transmitted. o To resist phagocytosis
 Peptidoglycan and teichoic acids
Pyogenic- due to accumulation of neutrophils, o Attachment to mucous membranes
baterial cells and fuids at the site of infection. and enable organism to resist
unfavorable conditions
 Micrococcus organisms may colonize
human skin but rarely causes infections S. AUREUS: EXTRACELLULAR ENZYMES
 Staphylococcus mostly associted with AND TOXINS
clinical infections  Coagulase
o Conversion of fibrinogen to fibrin;
may coat neutrophils to protect
STAPHYLOCOCCI organisms from phagocytosis
 Catalase +
 Gram +  Staphylokinase (fibrinolysis)
 On gram stain- spherical (0.5-1.5um) o Dissolvesfibrin clot and may
o Singly, pairs, clusters enable infection to spread
 Staphylococcus-(Gk word- “staphle”-
bunch of grapes)  Lipase
 Microscopy- cannot differentiate different o Hydrolyzes lipids in plasma and
species of this genus skin; associated with skin
 Non-motile infections such as boils,
 Non-spore forming carbuncles and furuncles
 Aerobic or facultatively anaerobic
o Except for S. sachharolyticus-  Hyaluronidases (Spreading Factor)
o Hydrolysis of hyaluronic acid
obigate anaerobe
present in connective tissues,
 Colonies
 which can result in the spread of Folliculitis
infection  Boils
 Furuncles
 Deoxyribonuclease (Dnase)  Carbuncles
o Degradation of DNA  Impetigo
o newborns,
 Exfoliatins/Exfoliative toxins infants
(epidermolytic toxin) and young
o Causes sloughing off of the children
epidermal layer of the skin  Predominant cause of joint infection in
 May result to SSS (Ritter adults
disease)
 Beta-lactamase (penicillinase) Furuncles Impetigo
o Hydrolysis and inactivation of
penicillin antibiotics through
breakdown of beta lactam ring in
penicillin molecule
Carbuncles
CYTOLYTIC TOXINS
 Leukocidins
o Lysis neutrophils and
macrophages; inhibit phagocytosis
o Lytic activity is due to an alteration
of the activity of the Na+/ K+ pump Sty

 Hemolysins
o Group of α, β, γ, δ, lyse RBCs
 α - can cause damage to
platelets and macrophage
 β - “hot-cold” hemolysin

α, γ, δ, hemolysins may lyse WBCs

Scalded Skin Syndrome
PVL  Also known as
 (Panton-Valentine Leukocidin) Ritter Lyell disease
 γ - hemolysin (in newborns),
 Exotoxin and lethal to PMNs  Caused by
Exfoliative toxins A
 Contributesinvasiveness of organisms
and B
o Produced only by few strains
o Separation of
o Associated with “community
the dermis
acquired” staphylococcal infection
(epidermal necrolysis)
o Mechanism of exfoliation is
ENTEROTOXINS
uncertain
 Group of 9 heatstable ( 100oC, 30mins.)
proteins: A, B, C, C2, D, E, and F, G, I, J
 Food poisoning: A, B, and D
o Heat stable and they act to
stimulate neural receptors in the
G.I. tract causing pain, vomiting,
and diarrhea within 6 hours of
ingestion
o Toxic Shock Syndrome: TSST-1 PROPOSED MECHANISM FOR SSS
(Formerly F)  The toxins likely act as proteases that
target the protein desmoglein-1 (DG-1),
CLINICAL SIGNIFICANCE an important cell-to-cell attachment
 INFECTION TYPE: Pyogenic in nature protein found only in the superficial
 Accompanied by swelling, redness, epidermis.
increase affected in temperature area and  The relative quantity of DG-1 in the skin
to the accumulation of leukocytes differs with age and may partially explain
the increased frequency of staphylococcal
Most common staphylococcal infection:
 scalded skin syndrome in children
younger than 5 years.

MODE OF TRANSMISSION
 Skin infections
o Direct contact
o Indirect contact (passed from
patient to patient by health care
workers)

o Fomite (contaminated bed linens TSST-1

and clothing)  is pyrogenic (fever causing) due to IL-1
induction
TREATMENT AND PREVENTION  causes erythroderma (red skin)
 Beta-lactam antibiotics (penicillin)  Causes enhanced susceptibility to
o S. aureus readily develops endotoxin shock.
resistance (methicillin and nafcillin)
 Oxacillin – remained effective against S. FOOD POISONING
aureus  Most common type of food poisoning in
 Incision and drainage of localized skin the U.S, results from ingestion of
and soft tissue preformed enterotoxin
o Symptoms: rapid onset of nausea,
TOXIC SHOCK SYNDROME vomiting, and diarrhea (2-6 hours
 A clinical syndrome characterized by after ingestion), abdominal pain
hypotension, fever, desquamation of the and cramping
palms and soles, chills, headache and
vomiting. COAGULASE NEGATIVE STAPHYLOCOCCI
 Primarily affects young menstruating
females using Tampons STAPHYLOCOCCUS EPIDERMIS
 Attributed to TSS-1 toxin  Resembles S.aureus in morphology and
 a rare but life-threatening condition gram stain preparation
caused by bacteria getting into the body o Gram (+) cocci in clusters
and releasing harmful toxins. It's often o White, creamy, raised growth on
associated with tampon use in young BA
women, but it can affect anyone of any o Non-hemolytic on BA
age – including men and children. o Growth, but lack of fermentation in
MSA
o Coagulase negative
o Susceptible to Novobiocin
 A normal flora of the skin and mucous
membranes (non-pathogenic)
o Has been found with increasing
frequency in immunosupressed
patients (Nosocomial)
o Associated with bacterial
endocarditis, frequently following
the insertion of artificial heart
valves
o Colonize prosthetic devices (CNS
shunts, intravascular catheters,
Slime production and prosthetic orthopedic devices
 this is an extracellular glycoconjugate that o Most common cause of Hospital-
helps the organism to adhere to smooth acquired
surfaces and is produced by CoNS as o Cause wound infections
well as S. aureus.
 Considered a contaminant in the past
o This is important in allowing
o Important cause of UTI’s
colonization of indwelling
associated pyelonephritis and
catheters, a major problem in
cystitis in young women and on
hospitalized patients.
older men who have an indwelling
catheters
  Coagulase negative, Dnase negative,
non-hemolytic
 Resistant to novobiocin (Tool for I.D)
o Zone of inhibition: 6-12 mm

STREPTOCOCCACEAE

FAMILY STREPTOCOCCACEAE  Contained in the cell wall of many

streptococci and forms the basis of
1. Aerococcus species serologic grouping into LANCEFIELD
 cause of endocarditis and meningitis in GROUPS A-H, and K-U.
immunosupressed individuals  Serologic specificity is determined by an
amino sugar:
2. Leuconostoc species
 Isolated from clinical sites

3. Pediococcus
 normal flora of the lower GIT and has
been isolated ocassionally from
abscesses.
 Extracts of group-specific antigen can be
4. Streptococcus and 5. Enterococcus
prepared through:
 Frequently associated with a variety of
o a. Extraction of centrifuged culture
human infections
treated with: hot HCl, Nitrous acid,
 Enterococcusspecies were previously
or formamide
classified as Streptococcus
o b. Enzymatic lysis of streptococcal
cell (e.g. pepsin or trypsin)
Pediococcus and Leuconostoc – resistant
o c. Autoclaving of cell suspension
to Vancomycin

GROUP A STREPTOCCI: STREPTOCOCCUS

STREPTOCOCCI PYOGENES
 Spherical to ovoid, catalase (-), gram (+)  Most streptococci that contain the group
organisms A antigen are S pyogenes.
 Nonsporeformer  S pyogenes is the main human pathogen
associated with local or systemic invasion
 non-motile except for rare motile strains
and poststreptococcal immunologic
of Group D Streptococci.
disorders.
 Generally non-encapsulated except for
 S pyogenes typically produces large (1
some strains of groups A,B,C,& D
cm in diameter) zones of hemolysis
Streptococci
around colonies greater than 0.5 mm in
 Facultatively anaerobic but some strains
diameter.
require added CO2 (5-10%) for their initial
isolation (microaerophilic strains –
Viridans Streptococci)
o Grown anaerobically and
aerobically
 Colonies on agar surface are:
o Translucent to milky
o Circular, and small or pinpoint with
a shiny surface
o 0.5 – 2.0 um in dm
VIRULENCE: Cellular components and
LANCEFIELD’S CLASSIFICATION extracellular products
 Lipotechoic acid and protein F
o present in the cell wall; responsible
for the adherence of the bacteria to
respiratory epithelial cells
 M protein
o major virulence factor of Group A
Streptococci which renders the
 organisms resistant to  A purulent exudate on the
phagocytosis tonsils, high
 Hyaluronic acid capsule temperature,
o assists the organism in avoiding and swollen
phagocytosis (in some mucoid lymphnodes
strains)  Usually lasts
five days
(with appropriate medication)

 Hemolysins

Streptolysin O (SLO):
 A membrane-damaging extracellular toxin
produced by hemolytic streptococci.
 Antigenic (able to illicit SEQUELAE OF STREPTOCOCCAL
immune response) INFECTION
 The membrane- Acute Rheumatic Heart Fever
damaging activity is  Occurs only after pharyngitis
measured by  Symptoms:
hemolysis of red-blood cell. o Fever, Myocarditis, Joint Swelling
 SLO is oxygen-sensitive and is easily o Chorea, Subcutaneous nodules
inactivated in its presence. o Rash (erythema marginatum) –
 –Produced not because it has a margin that
only by Group A spreads out from the center
hemolytic
streptococci but Acute Rheumatic Heart Fever
also by Group C
and Group G strains.
 Responsible for sub-surface hemolysis
 Enhanced when incubated anaereobically

Streptolysin S (SLS):
 oxygen stable, non-antigenic responsible
for surface hemolysis (β-hemolysis)
 Erythrogenic (pyrogenic) toxins
o responsible for the characteristic
rash inscarlet fever

 Hyaluronidase
o spreading factor

 Streptokinase
o enzyme that dissolves clots Acute Glomerulonephritis (AGN)
 Seen after pharyngeal or cutaneous
 Streptodornase or Dnase, NADase, infection
proteinases and other enzymes  Signs and Symptoms:
o Puffy face,
MODE OF TRANSMISSION “tea or Coca-
 Primarily by aerosols or secretions cola colored
 Food and milk borne (epidemics) urine
o Hypervolemia
DISEASE PRODUCED secondary to
 Most common cause of fluid retention
acute pharyngitis o Hypertension
 Classic Strep throat
with red swollen tonsils
and pharynx
SPECIMEN COLLECTION
Site considerations:

Oropharyngeal Swab
 Adequate for recovery of Streptococcus
pneumoniae, streptococcus pyogenes,
Haemophilus influenzae and
staphylococcus aureus.

Laboratory Diagnosis
 Microscopy
o gram staining (gram + cocci in
pairs and chains)
 Culture
o positive beta hemolysis in blood
agar
 Bacitracin test
o antibiotic
susceptibility test
with zone of
inhibition of growth
around the Bacitracin disc

Test to Diagnose Scarlet Fever

 Schultz-Charlton Reaction (Blanching
Phenomenon)
 based on the neutralization of
erythrogenic toxins when an antitoxin is
injected into the skin of a patient with
scarlet fever skin rashes fade or blanch
(+)
 used to diagnose whether the skin rashes
are due to scarlet fever or not