NSC 830 EKU Pharmacology-Antibiotics
|\ |\ |\ |\
exam questions with answers |\ |\ |\
Narrow spectrum |\
-Treats limited # of organisms
|\ |\ |\ |\
-Less likely to disrupt normal flora
|\ |\ |\ |\ |\
-Used when organism has been identified
|\ |\ |\ |\ |\
Extended spectrum |\
-Treats multiple organisms
|\ |\
-More likely to disrupt normal flora
|\ |\ |\ |\ |\
-Used when specific causative organism is unknown
|\ |\ |\ |\ |\ |\
Gram-positive bacteria |\
-bacteria that give a positive result
|\ |\ |\ |\ |\
in the gram-stain test. Gram-positive bacteria take up the crystal
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
violet stain used in the test, and then appear to be purple-
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
colored when seen through a microscope. This is because the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
thick peptidoglycan layer in the bacterial cell wall
|\ |\ |\ |\ |\ |\ |\
retains the stain after it is washed away from the rest of the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
sample, in the decolorization stage of the test.
|\ |\ |\ |\ |\ |\ |\
,-Despite their thicker peptidoglycan layer, gram-positive bacteria
|\ |\ |\ |\ |\ |\ |\
are more receptive to antibiotics than gram-negative, due to the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
absence of the outer membrane. |\ |\ |\ |\
-Gram + had a thick peptidoglycan layer in their cell wall (stain
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
purple)
Examples of Gram-positive bacteria |\ |\ |\
• Group A beta-hemolytic streptococci
|\ |\ |\ |\
• Streptococcus pneumonia
|\ |\
Gram-negative bacteria |\
-cannot retain the violet stain after the
|\ |\ |\ |\ |\ |\
decolorization step; alcohol used in this stage degrades the outer |\ |\ |\ |\ |\ |\ |\ |\ |\
membrane of gram-negative cells making the cell wall more
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
porous
and incapable of retaining the crystal violet stain. -Their
|\ |\ |\ |\ |\ |\ |\ |\ |\
peptidoglycan layer is much thinner and sandwiched between an |\ |\ |\ |\ |\ |\ |\ |\ |\
inner cell membrane and a bacterial outer membrane, causing
|\ |\ |\ |\ |\ |\ |\ |\ |\
them to take up the counterstain (safranin or fuchsine) and
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
appear Red or Pink |\ |\ |\
-Gram - had a thin peptidoglycan layer, but has an outer
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
membrane (stain red/pink) |\ |\
Examples of Gram-negative bacteria |\ |\ |\
,• Haemophilus influenza
|\ |\
• Neiserria gonococcus
|\ |\
Atypical bacteria |\
-bacteria that do not color with gram-staining, but remain
|\ |\ |\ |\ |\ |\ |\ |\ |\
colorless: they are neither gram-positive nor gram-negative.
|\ |\ |\ |\ |\ |\
-The atypical organisms lack a peptidoglycan layer so do not
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
retain crystal violet or safranin,
|\ |\ |\ |\
resulting in no color |\ |\ |\
-Peptidoglycans are the site of action of beta-lactam antibiotics |\ |\ |\ |\ |\ |\ |\ |\ |\
such as penicillins and cephalosporins, so atypical bacteria are
|\ |\ |\ |\ |\ |\ |\ |\ |\
naturally resistant to these drugs, which in this sense
|\ |\ |\ |\ |\ |\ |\ |\
also makes them "atypical" in the treatment of their infections.
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
Macrolides such as erythromycin however, are usually effective.
|\ |\ |\ |\ |\ |\ |\
Examples of Atypical bacteria |\ |\ |\
• Chlamydia pneumoniae
|\ |\
• Mycoplasma pneumoniae
|\ |\
• Legionella
|\
Drug Resistant Strep Pneumoniae (DRSP) risk factors
|\ |\ |\ |\ |\ |\
• Recent antibiotic use
|\ |\ |\
• Older (>65 yo)
|\ |\ |\
, • Multiple comorbidities (COPD, DM, HF, renal failure)
|\ |\ |\ |\ |\ |\ |\
• Daycare worker
|\ |\
• Alcoholism
|\
• Immunosuppressed (including chronic corticosteroid use >10
|\ |\ |\ |\ |\ |\ |\
mg/day long term) |\ |\
Drug Resistant Strep Pneumoniae (DRSP) Treatment
|\ |\ |\ |\ |\
• High dose amoxicillin (3-4 g/day)
|\ |\ |\ |\ |\
• Respiratory fluoroquinolones: moxifloxacin, gemifloxacin,
|\ |\ |\ |\ |\
levofloxacin (broad spectrum) |\ |\
• telithromycin (Ketek) - use limited due to hepatotoxicity
|\ |\ |\ |\ |\ |\ |\ |\
*this bacteria wont be suseptible to regular AB doses
|\ |\ |\ |\ |\ |\ |\ |\
Other factors to consider when determining drug selection
|\ |\ |\ |\ |\ |\ |\
• Allergy history
|\ |\
• Penicillins -risk of cross-allergy to cephalosporins
|\ |\ |\ |\ |\ |\
• Age
|\
• Renal function - neonates & elderly
|\ |\ |\ |\ |\ |\
• Pregnancy
|\
• Example: Contraindicated: tetracyclines (tetrogenic),
|\ |\ |\ |\ |\
fluoroquinolone (interfere w joints and cartilidge/bone growth |\ |\ |\ |\ |\ |\
-Immunocompromised status: Immunomompromised require |\ |\ |\ |\
bactericidals & extended therapy |\ |\ |\
|\ |\ |\ |\
exam questions with answers |\ |\ |\
Narrow spectrum |\
-Treats limited # of organisms
|\ |\ |\ |\
-Less likely to disrupt normal flora
|\ |\ |\ |\ |\
-Used when organism has been identified
|\ |\ |\ |\ |\
Extended spectrum |\
-Treats multiple organisms
|\ |\
-More likely to disrupt normal flora
|\ |\ |\ |\ |\
-Used when specific causative organism is unknown
|\ |\ |\ |\ |\ |\
Gram-positive bacteria |\
-bacteria that give a positive result
|\ |\ |\ |\ |\
in the gram-stain test. Gram-positive bacteria take up the crystal
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
violet stain used in the test, and then appear to be purple-
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
colored when seen through a microscope. This is because the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
thick peptidoglycan layer in the bacterial cell wall
|\ |\ |\ |\ |\ |\ |\
retains the stain after it is washed away from the rest of the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
sample, in the decolorization stage of the test.
|\ |\ |\ |\ |\ |\ |\
,-Despite their thicker peptidoglycan layer, gram-positive bacteria
|\ |\ |\ |\ |\ |\ |\
are more receptive to antibiotics than gram-negative, due to the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
absence of the outer membrane. |\ |\ |\ |\
-Gram + had a thick peptidoglycan layer in their cell wall (stain
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
purple)
Examples of Gram-positive bacteria |\ |\ |\
• Group A beta-hemolytic streptococci
|\ |\ |\ |\
• Streptococcus pneumonia
|\ |\
Gram-negative bacteria |\
-cannot retain the violet stain after the
|\ |\ |\ |\ |\ |\
decolorization step; alcohol used in this stage degrades the outer |\ |\ |\ |\ |\ |\ |\ |\ |\
membrane of gram-negative cells making the cell wall more
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
porous
and incapable of retaining the crystal violet stain. -Their
|\ |\ |\ |\ |\ |\ |\ |\ |\
peptidoglycan layer is much thinner and sandwiched between an |\ |\ |\ |\ |\ |\ |\ |\ |\
inner cell membrane and a bacterial outer membrane, causing
|\ |\ |\ |\ |\ |\ |\ |\ |\
them to take up the counterstain (safranin or fuchsine) and
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
appear Red or Pink |\ |\ |\
-Gram - had a thin peptidoglycan layer, but has an outer
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
membrane (stain red/pink) |\ |\
Examples of Gram-negative bacteria |\ |\ |\
,• Haemophilus influenza
|\ |\
• Neiserria gonococcus
|\ |\
Atypical bacteria |\
-bacteria that do not color with gram-staining, but remain
|\ |\ |\ |\ |\ |\ |\ |\ |\
colorless: they are neither gram-positive nor gram-negative.
|\ |\ |\ |\ |\ |\
-The atypical organisms lack a peptidoglycan layer so do not
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
retain crystal violet or safranin,
|\ |\ |\ |\
resulting in no color |\ |\ |\
-Peptidoglycans are the site of action of beta-lactam antibiotics |\ |\ |\ |\ |\ |\ |\ |\ |\
such as penicillins and cephalosporins, so atypical bacteria are
|\ |\ |\ |\ |\ |\ |\ |\ |\
naturally resistant to these drugs, which in this sense
|\ |\ |\ |\ |\ |\ |\ |\
also makes them "atypical" in the treatment of their infections.
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\
Macrolides such as erythromycin however, are usually effective.
|\ |\ |\ |\ |\ |\ |\
Examples of Atypical bacteria |\ |\ |\
• Chlamydia pneumoniae
|\ |\
• Mycoplasma pneumoniae
|\ |\
• Legionella
|\
Drug Resistant Strep Pneumoniae (DRSP) risk factors
|\ |\ |\ |\ |\ |\
• Recent antibiotic use
|\ |\ |\
• Older (>65 yo)
|\ |\ |\
, • Multiple comorbidities (COPD, DM, HF, renal failure)
|\ |\ |\ |\ |\ |\ |\
• Daycare worker
|\ |\
• Alcoholism
|\
• Immunosuppressed (including chronic corticosteroid use >10
|\ |\ |\ |\ |\ |\ |\
mg/day long term) |\ |\
Drug Resistant Strep Pneumoniae (DRSP) Treatment
|\ |\ |\ |\ |\
• High dose amoxicillin (3-4 g/day)
|\ |\ |\ |\ |\
• Respiratory fluoroquinolones: moxifloxacin, gemifloxacin,
|\ |\ |\ |\ |\
levofloxacin (broad spectrum) |\ |\
• telithromycin (Ketek) - use limited due to hepatotoxicity
|\ |\ |\ |\ |\ |\ |\ |\
*this bacteria wont be suseptible to regular AB doses
|\ |\ |\ |\ |\ |\ |\ |\
Other factors to consider when determining drug selection
|\ |\ |\ |\ |\ |\ |\
• Allergy history
|\ |\
• Penicillins -risk of cross-allergy to cephalosporins
|\ |\ |\ |\ |\ |\
• Age
|\
• Renal function - neonates & elderly
|\ |\ |\ |\ |\ |\
• Pregnancy
|\
• Example: Contraindicated: tetracyclines (tetrogenic),
|\ |\ |\ |\ |\
fluoroquinolone (interfere w joints and cartilidge/bone growth |\ |\ |\ |\ |\ |\
-Immunocompromised status: Immunomompromised require |\ |\ |\ |\
bactericidals & extended therapy |\ |\ |\
