LESSON 4: BRIEF HISTORY IN MICROBIOLOGY AND LABORATORY SAFETY AND INFECTION CONTROL Flashcards
An English scientist and architect, a polymath, recently called “England’s Leonardo”, who, using a microscope, was the first to visualize a microorganism.
Robert Hooke
states that the stretching of a solid body (metals, woods) is proportional to the force applied.
Elasticity (Hooke’s Law) -
Robert Hooke, an english scientist decided to examine thin slices of plant material and was struck by the appearance of regular box-like structures he names “cells” (smallest unit of life).
Cell History
founded compound microscope.
- Dutch microscopist who was the first to observe bacteria and protozoa (parasites).
His research on lower animals refuted the doctrine of spontaneous generation, and his observation helped lay the foundations for the sciences of bacteriology and protozoology.
Anton van Leeuwenhoek
found red blood cells.
Marcelo Malpighi
father of ancient bacteriology and scientific microscopy.
Leeuwenhoek -
study of bacteria.
Bacteriology
a German physician and microbiologist.
As one of the main founders of modern bacteriology, he identified the specific causative agents of tuberculosis, cholera, and anthrax, and gave experimental support for the concept of infectious disease, which included experiments on humans and animals
ROBERT KOCH
A French biologist, microbiologist, and chemist renowned for his discoveries of the principles of vaccination, microbial fermentation, and pasteurization. He is remembered for his remarkable breakthroughs in the causes and prevention of diseases, and his discoveries have saved many lives ever since.
Louis Pasteur
“Father of Modern Bacteriology”
Louis Pasteur
He demonstrated that microorganisms are present in the air and can contaminate sterile solutions, but the air itself does not create microbes “cross-contamination”
Louis Pasteur
A Scottish physician and microbiologist best known for discovering the enzyme lysozyme and the world’s first broadly effective antibiotic substance which he named penicillin.
Alexander Flemming
German physician and scientist who worked in the fields of hematology, immunology, and antimicrobial chemotherapy.
Paul Ehrlich
Among his foremost achievements were finding a cure for syphilis in 1909 and inventing the precursor technique to Gram staining bacteria.
Paul Ehrlich
is a bacterial infection usually spread by sexual contact. The disease starts as a painless sore — typically on your genitals, rectum or mouth. Syphilis spreads from person to person via skin or mucous membrane contact with these sores.
Syphilis
A process that kills “all forms” of microbial life including bacterial spores.
destruction of all forms of life.
Sterilization
Physical Methods (Sterilization) (5)
Incineration
Moist heat (steam under pressure)
Dry heat
Filtration
Ionizing radiation
Chemical Methods (Sterilization) (4)
Ethylene Oxide
Formaldehyde Vapor and Vapor Phase H2O2
Glutaraldehyde
Peracetic Acid
Most common method of treating infectious waste.
Safest method
Temperature: 870°C to 980°C
INCINERATION
act that bans incineration in the PH
Philippine Clean Air Act of 1999 and the Ecological Solid Waste Management Act of 2000.
Sterilize biohazardous trash and heat-stable object.
Machine needed: “Autoclave” - culture media, liquids, utensils, glass, pipettes, instruments.
Biological indicator: Bacillus stearothermophilus vials incubated at 56’C.
MOIST HEAT:
Longer exposure times and higher temperature than moist heat
Sterilize items such as glass wares, oil, or powders.
Biological indicator: Bacillus subtilis (laboratory contaminant)
DRY HEAT
Method of choice for antibiotic solutions, toxic chemicals, radioisotopes, vaccines and carbohydrates, which are all “heat sensitive”.
FILTRATION
Sterilizing disposables (e.g. plastic syringes, catheters, or gloves before use).
IONIZING
used for sterilizing evacuated tubes.
Gamma radiation
Most common.
Used in gaseous form for sterilizing heat-sensitive objects.
ETHYLENE OXIDE
Sterilized HEPA filters in BSCs(Biosafety Cabinets) - designed to remove organisms larger than 0.3um.
FORMALDEHYDE VAPOR & VAPOR PHASE H2O2
Sporicidal, used for medical equipment.
GLUTARALDEHYDE:
Effective in the presence of organic material, used for surgical instruments.
PERACETIC ACID
Destroys pathogenic organisms, but not necessarily all microorganisms or spores.
DISINFECTION
Physical Methods (Disinfection) (3)
Boiling
Pasteurization
Nonionizing Radiation
Chemical Methods (Disinfection) (2)
Chemical sterilant or Biocides
Antiseptics and Disinfectants
Antiseptics and Disinfectants (4)
alcohol
heavy metals
halogens
QUATS
100°C for 15 minutes.
Kills vegetative bacteria (bacterial cells that are metabolizing and undergoing binary fission. They are “alive” and replicating).
Boiling
63°C for 30 minutes or 72°C for 15 seconds.
Kills food pathogens without damaging the nutritional value or flavor.
PASTEURIZATION
3 types of pasteurization
LTH, HTST, UHT
Ultraviolet light (U.V) - causes DNA base pairs mismatching by producing “thymine” dimer.
Biological Indicator: Bacillus pumilis
NON-IONIZING RADIATION
Chemicals used to destroy all form of life.
CHEMICAL STERILANT/ BIOCIDES
Used for shorter periods
disinfectants
Used in living tissue
antiseptics
70% ethyl alcohol is more effective as a disinfectant that 95% alcohol.
ALCOHOL
penetrate the cell wall of the microorganism
coagulates the proteins.
70% Solutions alcohol
an eye infection.
Ophthalmia Neonatorum
a most common compound used for skin disinfection before drawing blood specimens for “culture” or surgery.
iodophor
Most often used in the form of sodium hypochlorite household bleach (1:10 ratio) dilution of bleach after blood spills.
CHLORINE
Detergents, inactivated by organic material such as blood.
QUATS (QUATERNARY COMPOUNDS):
In case of fire: RACE
Rescue, Alarm, Contain, Extinguish
Proper use of Fire Extinguisher: PASS
Pull, Aim, Squeeze, Sweep
TYPES OF FIRES (5)
Class A, Class B, Class C, Class D, Class K
Ordinary combustibles (woods & papers)
Class A
Flammable liquids & gases
Class B
Electrical, Energized Electrical Equipment (current)
Class C
Combustible Metals (magnesium/ manganese)
Class D
Cooking oils and Greases (kitchen)
Class K
Combination of practices, procedures, and equipment that protect the lab workers, public environment from infectious agents and toxins.
keep harmful agents from people
Biosafety
measures are taken to protect infectious agents and toxic from loss, theft, or misuse.
2 Keep people from harmful agents
Biosecurity
Remove particles that may be harmful to the employee who is working with infective biologic specimens
BIOSAFETY CABINETS
For institutional use
Suitable for work involving well-characterized agents not known to consistently cause disease in immunocompetent adult humans, and present minimal potential hazard to laboratory personnel and the environment.
Ex. Bacillus subtilis, Mycobacterium gordonae
Precautions includes standard good laboratory techniques
BIOSAFETY LEVEL 1
For laboratory set-up
Suitable for work involving agents that pose moderate hazards to personnel and the environment.
Most organisms can cause laboratory acquired infection.
BIOSAFETY LEVEL 2
Applicable to clinical, diagnostic, teaching, research, or production facilities where work is performed with indigenous or exotic agents that may cause serious or potentially lethal disease through the inhalation route of exposure
Agents are primary transmitted by aerosols (inhalation).
Observe level 2 procedures with additional lab clothing and controlled access to the laboratory
BIOSAFETY LEVEL 3
Required for work with dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections and life-threatening disease.
All procedures are performed under maximum containment.
Use mostly for research studies.
BIOSAFETY LEVEL 4
