Bad Bugs Treatment
Organism
Gram
Mechanism of resistance
+
SCC-Mec-2 (mecA) gene results in
altered PBP 2a beta lactams, like
methicillin can’t bind to.
SCC-Mec-4 (mecA) gene results in
altered PBP 2a beta lactams, like
methicillin can’t bind to. Some
additional susceptibility to other drugs.
Phenotypic change in cell wall that
results in making it thicker & creating
more D-Ala, D-Ala residues that “clog”
up Vancomycin’s ability to act
vanA gene encodes for a change to the
peptide terminus on NAM from D-Ala,
D-Ala to D-Ala-D-lac which stops
vancomycin from binding
AmpC beta-lactamase: hydrozlyzes the
B-lactam ring for all B-lactams EXCEPT:
cefepime & carbapenems look for
cefoxitin resistance on the
susceptibility report
SSTI, pneumonia,
bloodstream, surgical
site infections
SSTI, pneumonia
Vancomycin
SSTI, pneumonia,
bloodstream, surgical
site infections
Ceftaroline (Teflaro),
Daptomycin (Cubicin),
Linezolid* (Zyvox)
UTI, intra-abdominal
infections, bloodstream
Daptomycin, Linezolid,
No ceftaroline
(cephalosporins)
Nitrofurantoin (Macrobid) can
be used in UTI, Fosfomycin
(Monurol) can be used in UTI
UTI, intra-abdominal,
bloodstream
Cefepime, Carbapenems
Other non-Beta-lactam
classes: FQ, AGs, newer
combos: Avycaz, Vabomere
NOT: Zerbaxa
-
Extended spectrum beta lactamase
(ESBL)  hydrolyze all beta-lactams
EXCEPT carbapenems
UTI, intra-abdominal
infections, bloodstream
Carbapenems
-
Carbapenem resistance
UTI
Enterobacteriaceae (CRE)  produces
carbapenemases that hydrolyze ALL
beta lactams INCLUDING carbapenems.
Other non-Beta-lactam
classes: FQ, AGs, newer
combos: Avycaz, Vabomere,
Zerbaxa, Colistin or Polymyxin
B
Colistin or Polymyxin
HA-MRSA
+
CA-MRSA
+
hVISA/VISA
+
VRE
SPACE
-
Serratia
Pseudomonas
Acinetobacter
Citrobacter
Enterobacter
E.coli
Klebsiella
Proteus
Klebsiella & other
Enterobacteriaceae
*not bactericidal, depends on site of infectio
Common Infections
Drug of Choice
Bactrim
Newer Combo Agents:
Vabomere, Avycaz
Common Alternatives
Daptomycin (Cubicin) not in
pheumonia, Ceftaroline
(Teflaro), Linezolid (Zyvox)
Doxycycline, Minocycline,
Clindamycin (D-test), Linezolid
(Zyvox)
Parasite Treatment
Generic Name
Brand
Spectrum of Activity
Mechanism of Action
Pertinent ADEs
Other
Giardia
Tindamax
Tinidazole
Protozoa including
Giardia lamblia
Creation of reactive nitrogen radical may be
responsible for antiparsitic action. Released
nitrates may also damage DNA
Better tolerated then
Flagyl. Metallic taste.
Approved for
patients > 3 years
Quite toxic- Rarely used
anymore
Cichonism: tinnitus, HA,
nausea abdominal pain,
blurred vision. Blindness
Alkaloid from the
bar of the S.
American
cinchona tree.
Dates back
hundreds of years
Stereoisomer of
quinine
Malaria
Chlorquine sensitive
Malaria
Merozoiticide for
Plasmodium spp- kills
merozoites in the
blood
Chlorquine sensitive
Malaria
Merozoiticide for
Plasmodium spp
3 Hypothesized mechanisms:
1. DNA intercalation-sticking between DNA
base pairs in minor and major grooves
2. Inference with Plasmodium’s ability to
digest Hb
3. Inhibition of protozoal DHFR leading to
decreased production of DNA synthesis
Chlorquine sensitive
Malaria More
effective & safer than
the quinine quinidine
Weakly basic- accumulates in the acidic
lysosome of Plasmodium & stops the organism
from being able to digest hemoglobin for
protein & binds hemozoin to reduce RBC lysis
Lariam
Chlorquine-resistant
Malaria
Schizonticide. Associates with hemozoin inside
the erythrocyte.
Daraprim
Chlorquine resistant
Malaria and
Toxoplasmosis
Malarone
Chlorquine resistant
Malaria
Schizontocide. Inhibits DHFR to reduce
tetrahydrofolate production & creation of DNA
bases & methionine. 1000xs more selective for
Plasmodium DFHR than mammalian DHFR
Atovaquone- Inhibits parasite mitochondrial
electron transport resulting in decreased ATP
synthesis
Proguanil-Metabolized to cycloguanil which is
DHFR inhibitor for Plasmodium
Quinine
Quinidine
Aralen &
Chloroquine
Plaquenil
phosphate
Hydroxychloroquine
(Plaquenil)
Mefloquine
Pyramethamine
Atovaquone/
Proguanil
Can produce severe
hypoglycemia
Hypo or hypertension
Cardiotoxicity &
arrhythmias QTc
Pg 154
Contraindicated in
epilepsy
Very toxic:
Neuropsychiatric symp:
(Seizures, psychosis) QTc
Hematologic toxicity due
to MOA- Anemia,
leucopenia,
thrombocytopenia
Abdominal pain and
nausea. Up to 20%
DOC in many
areas without
resistance
Designed by US
Army
Very long half life
Give with Folinic
acid (leucovorin)
Can crush tabs for
kids
Generic Name
Brand
Spectrum of Activity
Mechanism of Action
Pertinent ADEs
Other
Hookworms, Pinworms
Albenza
Albendazole
Pin-X
Pyrantel Pamoate
Nematodes
(Hookworms,
Pinworms,
Roundworms),
Cestodes
Nematode
(hookworm,
roundworm,
pinworm)
Inhibits microtubule assembly which results in
decreased spindle formation during mitosis
and inhibits cell division. Microtubules
involved in helminth cytoskeleton
disruption. More selective for parasitic betatubulin than human.
Abdominal pain and
nausea, increased LFTs.
Well-tolerated
Depolarizing neuromuscular blocker of worms
by activation of nicotinic receptors resulting in
paralysis (analogous to succinylcholine)
Pamoate salt makes it
NOT absorbed Very
safe. GI symptoms
Secondary
mechanism of
action is inhibition
of ATP synthesis
Resistance occurs
with gene
mutation.
Lice, Scabies
Stromectol, Nematodes
Mectizan,
(Pinworms and
Sklice
Roundworms), lice,
scabies
Ivermectin
A-200, RID
Note: even though
used antihelminth and
antiectoparasite,
focus in this lecture is
use in lice and scabies
Ectoparasites (scabies
and lice)
Pyrethryins
Permethrin
Nix-1
Elimite,
Ectoparasites
Immobilizes organisms via muscle paralysis
from continued depolarization of glutamate
gated Cl channel. This channel is only in
invertabrates
Well-tolerated.
Used in vet med
and as agriculture
From chrysanthemums. Binds to the parasitic
sodium channel and results in consistent
depolarization leading to paralysis of the
organisms.
Combined with PBX to
decrease degradation
Lab synthesized. Increased stability
Not used with PBX
Human cyp
enzymes
metabolize these
rapidly making
them safe. Can be
toxic to animals
1% lice, 5%
scabies