4th lectureure Microbiology

Bacteria multiply in the bloodstream

Bacteremia

50%

Bubonic percentage of mortality

99 %

Pneumonic plague percentage of mortality

Black and blue

Hemorrhaging occurs in lymph nodes, resulting in ________ swelling or buboes

Bacterial endospores

Highest resistance

Protozoan cysts, some zygospores, naked virus, hepa B, polio virus, M. Tuberculosis, S. aureus, Psuedmonas sp.

Moderate resistance

Most bacterial vegetative cell, Odinary fungal spores and hyphae, envelope virus, yeast, trophozoites

Lowest resistance

Sterilization

the killing or removing all forms of microbial life including endospore. The term does not apply to prion

heating

Is the most commonly used method of sterilization

Sterile

Any material that has been subjected to heating process is called

Sterilant

Few chemicals that can be classified as sterilized agent because of their ability to destroy spores

Sterilization

Sometimes_________ is not necessary because most of the infectious disease are caused of non spore forming microbes

Commercial sterilization

Heat treatment that kills endospores of Clostrodium botulinum the causative agent of botulism in canned food

45

Sterilization does not kill endospores of thermophiles which are not pathogens and may grow at temperature above ______°

Disinfection

-Reducing the number of pathogenic microorganism to the point where they no longer cause disease

-is used onlu when discussing treatment of inanimate object

Reversal

Dis in latin word means

Corrupt

Inficere in latin word means

Antisepsis

When the chemical is used on skin or other tissue the process is called

aseptic

Describe as an enviroment or procedure that is free of contamination by pathogen

Sepsis

Greek for decay or putrid. Indicates bacteria contamination. In modern usage, it is defined as the growth of microorganism in the body or the presence of microbial toxins in blood and other tissues

Asepsis

Absence of significant contamination

aseptic technique

Are used to prevent contamination of surgucal instrument, medical personnel and the patient during surgery

medical asepsis

(clean technique) Reduce number of pathogens

Surgical asepsis

(Sterile technique) exclude mecrobes

Antisepsis

Process of removing of pathogens from living tissue

Degermation

Is the removal of microbes from a limited area of surfce by scrubbing through the use of soap or alcohol

sanitation

Is the process of disinfecting places and utensils used by the public to reduce the number of pathogenic microbes to meet accepted public health standards

Healthy

Sanitas in latin word means

Sanitizer

A compound such as soap or detergent used to sanitize

Kill

Cidal means

static character

______means to inhibit or prevent

Germicide

Also called microbicide, is any chemical that kills any pathogenic microorganisms

Germ

Germen in latin words means

Kill

Caedere means

Microbial death

Define by the scientists as the permanent loss of reductive ability under ideal environmental conditions

Cell wall

Maintains integrity of cell

Cytoplasmic membrane

-Controls passage of chemicals into and out of cell

-when damaged cellulr contents leak out

viral envelope

Responsible for for attachment of virus to target cell

Protien

Functions depends on 3D

Number of microbes

The more microbes present the more time it takes to eliminate population

Type of microbes

Endospores are very difficult to destroy. Vegetative pathogen vary widely in susceptibility to different methods of microbial control

Environmental influences

Presence of organic material tends to inhibit antimicrobials

time of exposure

Chemical antimicrobial and radiation treatment are mofe effective at longer times. In heat treatments longer exposure compensates for lower temperature

Enzymes

Denaturation of protien

Thermal death point

Lowest temperature at which all of the microbes in a liquid suspension will be killed im ten minutes

Thermal death time

Minimal lenght of time in which all bacteria will be killed at a given temperature

Decimal reduction time or D value

Time in minutes at which 90% of bacteria t agiven temperature will be killed. Used in canning industry

Moist heat

Kills microorganisms by coagulating their proteins

Hepatitis virus

Can survive up to 30 minutes of boiling

Endospores

Can survive up to 20 hrs ormore of boiling

Boiling

heat to 100°C or more at sea level

Autoclaving

Pressure applied to boiling water prevents steam from escaping

Pasturization

Prevent the spoilage of beverages

Classic method of pasteurization

Milk was exposed to 65°C for 30 mins

High temperature short time pasteurization

Used today, milk is exposed to 72°C for 15 seconds

Ultra high temperature pasteurization

Milk is bacteria at 140°C for 3 seconds and then cooled very quickly in a vacuum chamber

dry heat

Used for marerials that cannot be sterilized with or are damaged by moist heat

direct flaming

used to sterilize inoculating loops and needles

Incineration

Effective way to sterilize disposla item and bilologicalwaste

hot air sterilization

170o C for 2 hours can sterilize

Refrigeration

Temperature from 0to 70° bacteriostatic effect, reduce metabolic rate of most microbes so they cannot reproduce or produce toxin

Freezing

Temperature below 0°

flash freezing

does not kill most microbes

slow freezing

-more harmful becaus eice crystals distrupt cell structure

-over a third od vegetative bacteria may survive 1 year

-Most parasites are killed by a few days of freezing

Dessication

Absence of water that typically only have a bacteriostatic effect until water is reintroduced

Neisseria gonorrhoeae

Only survives about 1 hr

Mycobacterium tuberculosis

May survive several months

Viruses

Are fairly resistant to dessication

Clostridium spp. And baxillus spp

May survive decade

Lyophilization

freeze drying technique

Filtration

Over three years filters have been constructed from porcelain, glass, cotton, asbestos and diatomaceous earth

osmotic pressure

uses salts and sugars to create hypertonic environment; causes plasmolysis

Plasmolysis

As water leaves the cell plasma membrane shrinks away from cell wall, cell may not die but usually stops growing

yeast and mold

More resistant to high osmotic pressure

Staphyloccocus spp

That lives on skin are fairly resistant to high osmotic pressure

Fungi

Greater ability than bacteria to survuve hypertonic environment

Filtration

Removes microbes by trapping them in filter

High pressure

Denature protien

Lew temperature

Inhibits microbial growth

Desiccation

prevents metabolism

osmotic pressure

Causes plasmolysis

Plasmolysis

As water leaves the cell plsma membrane shrinks away from cell wall. Cell may not die but usually stops growing

Radiation

-Shorter the wavelength of an electromagnetic wave themore energy it carries and the farther it can penetrate

-shorter wavelength equal more enrgy and greater pentration

Ionization radiation

Wavelength shorter than 1 nm eelectron beams gamma rays and X rays

Nonionization radiation

Wavelength greater than 1 nm

Kelsey sykes capacity test

Standard alternative assessment approved by the european union

Phenol and phenolic

Reduce infection during surgery

Phenol

Was first used by lister as a disinfectant

Phenolic

Are chemical derivatives of phenol that have been chemically modified by the addition of halogens or organic functional group

Cresols

Derived from coal tar (lysol)

Biphenols

Effective against gram positive staphilococci and streptococci, used in nurseries, excessive use in infacts may cause neurogical damage

Halogens

-Effective alone or in compound

-intermediate level antimacrobial chemical

-believe that they damage enzymes via oxidation or by denaturing them

Tincture of iodine

-One of the first antiseptics used

-combine with amino acid tyrosine in proeins and denatures protein

-stains skin clothes somewhat irritating

Iodophors

Compounds with iodine that are slow releasing, take several minutes to act. Used as skin antiseptic in surgery. Not effective against bacterial endospores.

Chlorine

-When mixed in water forms hypochlorous acid

-used to disinfect drinking water pools and sewage

-chlorine is easily inactivated by organi c materials

Sodium hypochlorite

Is active ingredient of bleach

Chloramines

Consists of chlorine and ammonia. Less effective as germicides

Alcohol

-Kill bacteria fungi but not endospores on naked viruses

-act by denaturing proteins and disrupting cell membranes

-evaporates leaving no residues

Ethanol

Drinking alcohol. Optimum concentration is 70%

Isopropanol

Rubbing alcohol. Better disinfect than ethanol. Also cheaper and less volatile