Chapters 9, 24, 25 and 26 – Flashcards
Unlock all answers in this set
Unlock answers| 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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