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56 Cards in this Set
- Front
- Back
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Bacteria is also known as what? |
prokaryotes - single-celled organisms lacking a true nucleus and nuclear membrane (rigid cell wall and structure of the cell wall determines shape) |
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What is it called when cocci bacteria appear in clusters? |
staphylococci |
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What is it called when cocci bacteria are arranged in chains? |
streptococci |
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Bacteria reproduce by cell division about every _______________. |
20 minutes |
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Gram staining method was devised by _________________ (person) in _______ (year). |
Hans Christian Gram, a Danish bacteriologist; 1882 |
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How is gram staining determined? |
by the ability of the bacterial cell wall to retain a purple stain by a basic dye |
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What is it called when a bacteria is stained by the gram staining method? |
gram-positive
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What is it called when a bacteria is NOT stained by the gram staining method? |
gram-negative |
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What are some examples of gram-positive bacteria? |
staphylococcus aureus, streptococcus pneumoniae, group B streptococcus, and clostridium perfringens |
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What some examples of gram-negative bacteria? |
neisseria meningitides, escherichia coli, and haemophilus influenzae |
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what is cell lysis? |
cell death |
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Many bacteria produce this enzyme, which destroys beta-lactam antibiotics such as penicillins and cephalosporins. |
beta-lactamase |
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Antibacterials and antimicrobials are substances that _________________________________. |
inhibit bacterial growth or kill bacteria and other microorganisms including viruses, fungi, protozoa and rickettsiae |
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Do antibacterial drugs act along? If not, what is also possibly needed? |
No; natural body defenses, surgical procedures to excise infected tissues, and dressing changes |
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Who founded penicillium notatum (penicllin)? |
Alexander Fleming, a British bacteriologist in 1928 |
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What is penicillium notatum? |
it is a "mold" that inhibits bacterial growth |
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Who developed penicillin so it could be used commercially? |
Howard Florey in 1939 |
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What do bacteriostatic drugs do? |
inhibit the growth of bacteria |
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What do bactericidal drugs do? |
kill bacteria |
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What are two examples of antibacterial drugs that have a bacteriostatic effect? |
tetracycline and sulfonamides |
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What are two examples of antibacterial drugs that have a bactericidal effect? |
penicillins and cephalosporins |
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What occurs if the serum peak level is too high for antibiotics? |
drug toxicity |
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What occurs if the serum trough level is below the therapeutic range for antibiotics? |
the patient is not receiving an adequate antibiotic dose to kill the targeted microorgansim |
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What are the 5 mechanisms of antibacterial action that are responsible for the inhibition of growth or destruction of microorganisms? |
1) inhibition of bacterial cell-wall synthesis 2) alteration of membrane permeability 3) inhibition of protein synthesis 4) inhibition of the synthesis of bacterial RNA and DNA 5) interference with metabolism within the cell
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What is pharmacokinetics? |
it is what controls the time factor of the drug being attracted to and attaching to the binding sites of the bacterial cell wall, increasing its effect of the antibacterial action - distribution, half-life, and elimination |
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Antibacterials that have a longer __________ usually maintain a greater _______ at the binding site, causing _____ dosages that are required. |
half-life; concentrations; less |
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Does protein binding have a major influence on the effectiveness of most antibacterial drugs? |
no |
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Does exposure time for the antibacterial drug play an important role in bacterial eradication? |
yes |
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What does the duration of time used for antibacterial drugs vary on? |
* type of pathogen * site of infection * immunocompetence of the host |
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When is the antibacterial drug does effective? |
when it stays above the MEC (minimum effective concentration |
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Why are antibacterial drugs used? |
to achieve the MEC (minimum effective concentration) necessary to halt the growth of a microorganism |
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What factor's influence the body's ability to fight infection? |
*age *nutrition *immunoglobulins *WBCs *organ funtion *circulation (has to get to the site of infection) |
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What happens if bacteria is sensitive to a drug? |
that pathogen is inhibited or destroyed |
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What happens if bacteria is resistant to a drug? |
it continues to grow, despite administration of that antibacterial drug |
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What is inherent resistance (natural resistance)? |
occurs without previous exposure to the antibacterial drug |
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What is acquired resistance? |
caused by prior exposure to the antibacterial drug - repeated exposures can cause the organism to evolve and become resistant |
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What does penicillinase (enzyme produced by some microorganisms - staphylococcus aureus - do to penicillin? |
it metabolizes it causing the drug to be ineffective |
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When antibiotics are used frequently, __________ occurs. |
antibiotic resistance |
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Infections acquired while patients are hospitalized are called ____________________. |
nosocomial infections |
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What are many nosocomial infections cause by? |
drug-resistant bacteria |
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Bacteria can transfer their __________________ to another bacterial species - can pass along high resistance to a more virulent and aggressive bacterium. |
genetic instruction |
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What was the first penicillinase-resistant penicillin developed? |
methicillin (staphcillin) - was a response to a resistance of S. aureus |
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Methicillin-resistant staphylococcus aureus (MRSA) is resistant to what? |
methicillin and all penicillins and cephalosporins |
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When did MRSA begin to emerge into the community? |
1981 |
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What is the treatment of choice for MRSA? |
vancomycin (Vancocin) |
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What is VREF? |
vancomycin-resistant enterococcus facecium |
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What is VRSA? |
vancomycin-resistant MRSA |
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Linezolid is effective against what? |
MRSA, VREF, and penicillin-resistant streptococci |
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What is cross-resistance? |
occurs between antibacterial drugs that have similar actions, such as penicillins and cephalosporins |
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what test can detect the infective microorganism present in a sample and what drug can kill it? |
Culture and Sensitivity test (C&S) |
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What delays the development of microorganism resistance? |
multi-antibiotic therapy (daily use of several antibacterials) |
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What does it mean when an antibiotic combination is additive? |
effect is equal to the sum of effects of two antibiotics |
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What does it mean when an antibiotic combination is potentiative? |
occurs when one antibiotic potentiates the effect of the second antibiotic, increasing their effectiveness |
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What does it mean when an antibiotic combination is antagonistic? |
combination of a drug that is bactericidal (penicillin) and bacteriostatic (tetracycline) - when used together the desired effect may be greatly reduced |
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What is a narrow-spectrum antibiotic? |
usually effective against one type of organism |
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What are broad-spectrum antibiotics? |
effective against both gram-negative and gram-positive organisms (frequently used to treat infections when the offending microorganism has not been identified by C&S |
