Chapters 9, 24, 25 and 26

Endospores are called resting bodies because

 

they do not metabolize and are resistant to heating, various chemicals and many harsh enviromental conditions

 

Endospores are not for

 

reproduction.  They form when essential nutrients or water are not available.

Once an endospore forms in a cell

 

The cell will disintergrate

 

Endospores can remain dormant

 

for long periods of time

 

 

Endospores are impermeable to most stains, so _________________

 

heat is usually applied to drive the stain into the endospore.

 

 

Once stained, the endospores do not readily

 

decolorize

 

 

Endospores are stained with what type of stain?

 

 

Schaeffer – Fulton stain

 

 

Most capsules are composed of

 

Polysaccharides, which are water soluble and uncharged

 

 

Because of the capsule’s NONIONIC nature,

;

simple stains will not adhere to it.

;

;

Most capsule staining techniques stain the bacteria and the background leaving the capsules

;

;

unstained – essentially a negative capsule stain.

;

;

When bacteria such as streptococcus pneumoniae have a capsule, the body’s white blood cells cannot

 

 

phagocytize the bacteria.

 

Many, bacteria are Motile, meaning  

 

 

They have the ability to move from one position to another in a direct manner.

 

 

Myoxybacteria move by exhibiting a

 

gliding motion

 

 

Spirochetes move by

undulating using axial filaments

 

 

_________________ can be stained after being carefully coated with mordant.

flagella

 

 

Flagella stain reagent contains

 

alum and tannic acid mordants and crystal violet stains

 

 

Flagella have two main types

 

Peritrichous (all around the bacterium)

and

polar (at one or both ends of the cell)

 

 

Motility can be determined by observing

 

hanging drop or wet mount preparations of unstained bacteria, flagella stains, or inoculation of soft (or semisolid) agar deeps.

 

Wide variety of chemicals called _______ are available for controlling the growth of microbes.

 

antimicrobial agents

 

 

These are chemical agents used on inanimate objects to lower the level of microbes

 

Disinfectants

 

These are chemicals used on living tissue to decrease the number of microbes on their surfaces.

 

Antiseptics

 

This causes the temporary inhibition of bacterial growth

 

Bacteriostatic agents

 

 

These agents cause bacterial death

 

Bacteriocidal Agents

 

 

No single chemical is the best to use in all situations.

 

Antimicrobial afents must be matched to specific organisms and enviromental conditions

 

 

Additional variables to consider in selecting an antimicrobial agent include

 

PH, solubility, toxicity, organic material present adn the cost.

 

 

The important criteria for evaluating the effectiveness of antimicrobial agents are

 

Their concentration, length of contact, whether it is lethal (cidal) or inhibiting (static)

 

 

Before a disinfectant is selected, the ___________ for the most common and persistent microbe identifies at a health facility should be determined

 

Decimal reduction time (DRT)

 

 

The DRT (Decimal reduction time) is the time it takes

to kill 90% of the test microbial population.

 

 

The standard method for measuring the effectiveness of a chemical agent is

 

The American Official Analytical Chemist’s

Use-dilution test

;

;

In the use-dilution test the effectiveness of a disinfectant can be determined by the

;

;

amount of resulting growth

;

;

The use-dilution test is limited to bactericidal compounds and cannot be used to evaluate

;

bacterial static compounds

;

The observation that some microbes inhibited the growth of others was made by

;

Pasteur

;

;

Pasteur observed that by

;

infecting an animal with pseduomonas aeruginosa protected the animal against bacillus antracis

_____________ is a substance produced by one microorganism that inihits other microorganism

;

;

Antiobiotic

;

;

_____________ produces nearly 70% of all antibiotics

;

Streptomeces bacteria

;

;

Antimicrobial drugs are used

;

internally whether natural (antibodies)

or synthetic.

To treat an infectious disease the doctor needs to

;

select the correct antimicrobial agent intelligently and administer the appropriate dose and follw that treatment to be aware of the resistant forms of teh organism that might occur

The clinical laboratory isolates the

;

pathogen (disease causing organism) from a clinical sample and determines its sensitivity to antimicrobial agents.

in a disk diffusion method,

petri plate containing an agar growth medium is

;

inoculated uniformly over its entire suface and paper disks impregnated with various antimicrobial afents are place on the suface of the agar.; An effective agent will inihit bacterial growth and measurements made of the ZONES OF INHIBITION around the disks.

;

;

The ___________________ of antibiotic is determined by testing for bacterial growth in dilutions of the antibiotic in nutrient broth

;

Minimum inhibitory concentration (MIC)

;

;

When inhibitions zones can be compared to a standard table, we then use the _____________ to determine susceptibility

;

disk diffusion method

;

;

The diameter of zones of inhibition is measured in milimeters and be the bacteria’s  __________, __________ and __________ to the agent being tested

 

Resistance

Intermediate

Susceptibility

Ampicillin is a __________ and its mode of action is

 

 

Semisynthetic Penicillin

 

Inhibits cell wall synthesis

 

 

Erythromycin is a __________ type of microbial agent and its mode of action is

 

Macroglide

 

Inhibits protein synthesiss

Penicillin G is a ______________ type of antimicrobial agent and its method of action is ___________.

 

B – Lactam

 

Inhibits cell wall synthesis

Streptomycin is a __________ type of antimicrobial agent

and its method of action is ____________. 

 

Aminoglyside

 

inhibits protein synthesis

 

 

Tetraycycline is  a ______________ type of antimicrobial afent and it method of action is ____________.

 

Tetraycycline

 

Inhibits protein synthesis

 

 

Ciproflaxin is a __________ type of antimicrobial agent and its method of action is ________

Vancomycin is a ____________ type of antimicrobial agent and its mode of action is ___________.

 

 

glycopeptide

 

inhibits cell wall synthesis

Microorganisms that are more or less permanent are called

 

normal microbiata

 

Microbes that are only present for days or weeks are referred to as

 

Transient microbiata

He noted that aseptic methods ws directly related to the incidence of puerperal fever and other diseases.

 

Ignaz Semmelweis

 

 

 

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