Wk 9 Flashcards
(45 cards)
Infection?
The invasion and multiplication of pathogenic microorganisms in body tissues, causing disease by local cellular injury, secretion of a toxin or by antigen-antibody reaction in the host.
Local infection?
involving the skin or internal organs may progress to a systemic infection
Systemic infection?
involves the whole body or a specific system rather than a localized area of the body
Colonisation?
the localized presence of microorganisms in the body tissues or organs; these micro organisms can be pathogenic or part of normal flora
Inflammation?
protective mechanism of body tissues in response to invasion or toxins produced by colonizing micro organisms
Bacteraemia?
the presence of viable bacteria in the circulatory system
Septicaemia?
A systemic infection caused by micro organisms multiplication in the circulation
Sepsis?
A syndrome with multiple organ involvement that is a result of micro organisms or their toxins circulating in the blood
Gram Stain?
A sequential procedure involving crystal violet and iodine solutions followed by alcohol that allows the rapid classifications of organisms into groups .
Bacteriostatic agents?
inhibit bacterial growth allowing intact and active host defense systems time to remove the invading micro organisms
Bactericidal agents?
causes bacterial cell death and lysis and eradicate the infection, which is important especially in situation of impaired host defenses
Intrinsic Resistance?
refers to the organisms innate chromosomal (genetic) makeup that predictably specifies the resistance
Acquired resistance?
arises in a organism because of a change (mutation) in its genetic makeup or because of the acquisition of new genetic information (New DNA) specifying new mechanism of resistance that the organism did not previously
Discuss 3 distinct mechanisms by which bacteria can develop drug resistance
1) the antimicrobial drug is unable to reach the potential target site of its action organisms such as Pseudomonas form a protective membrane that prevents the antibiotic from reaching the cell wall
2) the micro organism produces an enzyme that modifies or destroys the structure of the antibiotics
3) the target site for the drug is altered so the drug can no longer bind to the target
Antibiotics that inhibit bacterial cell wall synthesis?
Penicillin’s (narrow spectrum- benzylpenicillin and moderate spectrum- amoxycillin) , Cephalosphorins, Carapenems, Glycopeptides
Penicillin’s are?
antibiotics derived from several strains of common moulds often seen on bread or fruit. They include narrow spectrum- benylpenicillin and moderate spectrum- amoxycillin
Cephalosporins?
inhibit bacterial cell wall synthesis and are also bactericidal because they inhibit cell division and growth, rapidly dividing bacteria are affected most.
1st generation- cephazolin are primarily active against gram positive.
2nd generation- cefaclor increased activity against gram negative microorganisms
3rd generation- ceftazidime active against gram negative
What are the 4 bacterial protein synthesis inhibitors?
Macrolide antibiotics, lincosamides, aminoglycerides and tetracyclines
What are Tetracyclines? examples?
a bacterial protein synthesis inhibitor and the first broad spectrum antibiotics developed after a systmatic search fir antibiotic producing micro organisms in soil.
Doxycycline, minocycline and tetracycline.
What are aminoglycerides? examples?
a bacterial protein synthesis inhibitor and potent bactericidal antibiotic usually reserved for serious or life threatening infections. Very effective against gram negative bacteria but have limited activity on gram positive bacteria.
Amikacin, gentamicin
What are Macrolide antibiotics? examples?
bacterial protein synthesis inhibitors. They inhibit bacterial RNA- dependant protein synthesis by binding to the 50S ribosomal subunit.
Azithromycin, erythromycin
What are Lincosamides? examples?
a bacterial protein synthesis inhibitor. they inhibit protein synthesis by binding to the bacterial 50S ribosomal subunit and preventing peptide bond formation.
Clindamoycin
What are the inhibitors of DNA synthesis?
Fluroquinolones, Synthetic, broad spectrum agents with bactericidal activity.
Why are antiretroviral drugs often used in combination for the treatment of HIV?
Administering them in combination therapies has decreased viral loads and increased CD4 counts ( a glycoprotein found on the surface of immune cells such as T cells)
