Introduction to Bacteriology and Microbial Cell Structure Flashcards
CLEANING
• Cleaning or (to clean) is the mechanical process
(scrubbing) using soap and water or detergent
and water to remove all visible dirt, debris, and
many disease-causing germs from tools,
implements, and equipment.
SANITATION
• To sanitize is a chemical process for reducing the
number of disease-causing germs on cleaned
surfaces to a safe level.
DISINFECTION
• To disinfect is a chemical process that uses specific products to destroy harmful organisms (except for bacterial spores) on environmental surfaces.
STERILIZATION
• To sterilize is the process that completely
destroys all microbial life, including spores.
Bacteriology –
The science that deals with the
study of Micro-organisms called Bacteria.
• The science of bacteria, the causative agents of a
member of infectious diseases
TYPES OF BACTERIA
- Non-Pathogenic
2. Pathogenic
NON-PATHOGENIC
Beneficial or harmless; Most Numerous
• Useful functions - decompose refuse, improve
some conditions
• Belong to saprophyte group – require dead matter
for growth (a type of nonpathogenic bacteria that
causes dead organic matter to decay thus helps
enrich the soil.
• Some cultures (acidophilus) are used to make
yogurt and some cheese, bacteria in yeast cause
bread to rise and other bacteria create the alcohol
in wine.
• Stimulates immune response
• Helps metabolize food
• Some cultures are used to produce penicillin
• Special types of milk used for gastrointestinal
disorders
• Protects against infection
PATHOGENIC
Pathogenic Bacteria (germs or microbes) are harmful microorganismpokops, and although in the minority, they can cause disease or infection in humans when they invade the body, plant or animal tissue.
BLOOD
BORNE PATHOGENS.
Disease-causing bacteria or viruses that are
carried through the body in the blood or bodily
• Fluids like HIV and hepatitis
COCCI –
round shaped organism, appear in groups or singularly. There are 3 forms of cocci bacteria: • Staphylococci or Staph o Pus Forming o Grow in bunches or clusters like grapes o Generally Produce LOCAL INFECTIONS
Streptococci
o Pus Forming
o Grow in chains
Diplococci
o Grow in PAIRS
o Causes bacterial Pneumonia
BACILLA –
short rod-shaped organism (Short, Thin, Thick) • most common • Produce Diseases such as Influenza(Flu), Tetanus(Lockjaw), Typhoid Fever, Leprosy, Tuberculosis, Diphtheria
SPIRILLA – Corkscrew or Spiral Shaped
organisms
o Subdivided into many groups a) Most common – Treponema Pallida which causes syphilis b) Borrelia burgdorferi which causes Lyme disease (caused by ticks) c) Cholera
MOVEMENT OF BACTERIA
Different bacteria move in different ways: either by
self-movement (motility) or by use of flagella or
cilia
COCCI BACTERIA are transmitted in the air, in
dust or within the substance in which they settle,
they do not have motility/ self-movement.
Bacilli and spirilla are both capable of
movement
use flagella or cilia (slender,
hairlike, whip=-like extensions).
how do Flagella and Cilia differ?
Flagella- longer, snake-like
Cilia- small, rowing motion
ACTIVE OR VEGETATIVE STATE
Grow and Reproduce
1. Conditions are considered to be favorable for
growth when conditions are: dark, dirty, damp
and warm bacteria will grow and multiply.
how long does it take for a typical bacterium to differentiate?
This division happens as often as every 20 minutes. (up to 16 million in ½) o That is why some bacteria are used for bio-terrorism because the rate of reproduction of bacteria is very fast
INACTIVE (SPORE FORMING STAGE)
When favorable conditions cease to exist (dry, bright, clean) o Bacteria die and/or cease to multiply o Certain bacilli such as anthrax and tetanus bacilli coat themselves with a hard waxy outer covering called a spore which can withstand long periods of famine, dryness and unsuitable temperatures. The spores are not harmed by disinfectants, extreme heat (water boils at 212 F., extreme cold (liquid helium freezes at 507 F., chemicals or sunlight.
What is the only way to kill spores?
Only sterilization can kill
bacterial spores.
BACTERIAL INFECTIONS
An INFECTION occurs when body tissues are
invaded by disease-causing Or pathogenic
bacteria.
• There can be no bacterial infection without the
Presence of pathogenic bacteria
Pus is a sign of a bacterial infection. So, if bacteria
are eliminated, then clients cannot become infected
How do you know if the infection is of Pseudomonas?
when the pus is blue in color
LOCAL INFECTION
• Limited to one area (ex: pimple, abscess and
boils).
• Staphylococci (staph) most common human
bacteria, carried by about 1/3 of the population.
Can be picked up on doorknobs and other
surfaces, shaking hands and unclean
implements.
• Responsible for food poisoning and toxic Shock
syndrome.
GENERAL INFECTION
• Spreads throughout the body through the bloodstream (ex. Blood poisoning and syphilis)
what are the various causes of infection?
o Unclean hands, instruments, open sores & pus, mouth & nose discharge, using and sharing of towels, drinking cups, uncovered coughing, sneezing, and spitting in public. o Enter the body through the mouth, eyes, nose, breaks or wounds in the skin o Contagious or communicable – Disease spreading from one person to another by direct or indirect contact. § Best control is ISOLATION and HYGIENE
UNBROKEN SKIN
• First line of defense
Healthy person’s body secretions such as perspiration and digestive juices
discourage bacterial growth
BLOODSTREAM
- White corpuscle to devour bacteria
* Antitoxins to counteract toxins caused by bacteria
HUMAN DISEASE CARRIER
• Immune
o An individual who is personally immune to disease, yet carries the germ that can
infect other people (ex. Typhoid fever)
METHODS OF DECONTAMINATION
• Method #1 o Cleaning first (sanitation or sanitizing) o Then disinfecting with an appropriate EPA registered disinfectant (most often used is Lysol/chloric oxide/sodium hypochlorite) • Method #2 o Cleaning then sterilization o Sterilization is the process that completely destroys all microbial life, including spores o This method destroys all microbes and spores through heat and pressure in an autoclave
Wet disinfection containers
A. Barbicide jars
• Glass –barbicide disinfectant
• Used for combs
Disinfection tray
- Hard plastic-barbicide disinfectant
* Used for nail implements
Disinfection container
• Nonmetal, large, deep enough to keep implements completely submerged • Must have a closeable cover • Ship shape disinfectant • Used for brushes, perm rods, rollers, combs
DRY DISINFECTION CONTAINER
AIRTIGHT CABINET OR DRAWER THAT HAS A CHEMICAL AGENT IN IT.
• Station with Steri-dry fumigant
ULTRAVIOLET RAY DRY DISINFECTION
CONTAINER
• Uses UV ray bulbs that have a germicidal effect o Meaning they kill most bacteria and some viruses, o Also dries the implements in it: brushes, rollers, pw rods, combs, etc.
What are antiseptics?
Are chemical germicides formulated for use
on the skin and are registered and regulated
by the FDA.
which type of antiseptics is less drying to the skin?
Benzalkonium
where should you NOT use antiseptics?
Instruments and other surfaces
How should one deal with an exposure event?
CONTACT WITH BLOOD OR BODY FLUID
• An EXPOSURE INCIDENT is contact with nonintact (broken) skin, blood, body fluids or other
potentially infectious materials that is the result of
the performance of an employee’s duties.
• Never attempt to clean or disinfect any used tool
or implement at your workstation.
• Proper cleaning and disinfecting should only be
accomplished in a specified area of the salon and
requires the use of clean, warm running water, a
scrub brush, and liquid soap for cleaning and
disinfectant solution for disinfecting.
Bright-field microscopy
• Differences in the contrast between specimen and surrounding medium
Phase-contrast microscopy
• Differences in phases of light depending on the property of structure it passes
Darkfield microscopy
• Light reaches the specimen from the sides
Fluorescence Microscopy
specimens that are fluorescent
Those that do not naturally fluoresce maybe stained with a group of fluorescent dyes called
fluorochromes.
Flourosecne Microscopy is used for which microorganism?
Mycobacterium tuberculosis
immunofluorescence.
In this technique, specific antibodies (eg, antibodies to Legionella pneumophila) are chemically labeled with a fluorochrome such as fluorescein isothiocyanate (FITC)
Electron microscope
The high resolving power of electron microscopes
has enabled scientists to observe the detailed
structures of prokaryotic and eukaryotic cells.
• The superior resolution of the electron microscope
is due to the fact that electrons have a much
shorter wavelength than the photons of white light.
• An important technique in electron microscopy is
the use of “shadowing.”
Other important techniques in electron
microscopy include the use of ultrathin sections of
embedded material
A method of freeze-drying specimens that prevents the distortion caused by conventional drying procedures, and the use of negative staining with an electrondense material such as phosphotungstic acid or uranyl salts. o Without these heavy metal salts, there would not be enough contrast to detect the details of the specimen.
TEM
Response to electrons fired by an electron gun
• They give a ray of electrons to the specimen by
firing it with an electron gun and they will see the
response
• Was the first to be developed
• Uses a beam of electrons focused by an
electromagnetic condenser lens onto a thin
specimen.
What is the resolving power of TEM microscopy?
TEM can resolve particles 0.001 μm apart.
Viruses with diameters of 0.01–0.2 μm can be
easily resolved.
What are classified as Gram-positive and Gram-negative?
Most bacteria are classified as gram-positive or gram
negative according to their response to the Gram staining procedure.
• This procedure was named for the histologist Hans
Christian Gram, who developed this differential staining
procedure in an attempt to stain bacteria in infected
tissues.
• The Gram stain depends on the ability of certain bacteria
(the gram-positive bacteria) to retain a complex of crystal
violet (a purple dye) and iodine after a brief wash with
alcohol or acetone
Gram-Positive
• Thick layer (20-80nm) • Main composition: o Teichoic, teichuronic acids that hold layers together (50% dry weight of wall, 10% of the cell) § The teichoic acids constitute major surface antigens of those gram-positive species that possess them, and their accessibility to antibodies has been taken as evidence that they lie on the outside surface of the peptidoglycan. § In the pneumococcus (Streptococcus pneumonia), the teichoic acids bear the antigenic determinants called Forssman antigen.
Gram-negative
• Thin layer (2nm) o Outer membrane (bilayered structure, inner part similar with cell membrane, outer part has lipopolysaccharide (LPS)) o What is unique is that it has lipopolysaccharide on the outer part o The ability of the outer membrane to exclude hydrophobic molecules is an unusual feature among biologic membranes and serves to protect the cell (in the case of enteric bacteria) from deleterious substances such as bile salts. Because of its lipid nature, the outer membrane would be expected to exclude hydrophilic molecules as well.
Porins
o special channels capable of doing passive diffusion of LMW hydrophilic compounds o Large antibiotic molecules penetrate the outer membrane relatively slowly, which accounts for the relatively high antibiotic resistance of gram-negative bacteria.
Special molecule LPS
o Made up of lipid A and core o Antigenic site, endotoxin o LPS is synthesized on the cytoplasmic membrane and transported to its final exterior position. o The presence of LPS is required for the function of many outer membranes proteins.
What is the toxigenic determinant of G -ve?
Lipopolysaccharide is a
toxigenic determinant of
gram-negative
Lipoprotein
o Combination of lipid and protein o Stabilizes outer membrane o Lipoprotein is numerically the most abundant protein of gram-negative cells (ca 700,000 molecules per cell)
MYCOBATERIUM TUBERCULOSIS
Cell wall with large amount of waxes, resistant to harsh chemicals (mycolic acid) • Acid fast bacilli o Cannot be reacted upon by the normal gram stain, you have to use other components o Dye introduced into these cells by heating or treatment with detergent, cannot be removed by dilute HCL
site of action of penicillin
o Acts on the cell wall; that’s why some bacteria don’t have a cell wall so that antimicrobial agents cannot act on them, that’s the defense mechanism of the bacteria
example of a wall-less bacterium
pneumococcus, Neisseria, Anthrax
