1) MTB ID Flashcards
Antibiotics for MSSA IV?
oxacillin/nafcillin or cefazolin
Antibiotics for MSSA oral?
dicloxacillin or cepalexin
Antibiotics for MRSA, severe infection?
vancomycin, linezolid, daptomycin, ceftaroline, tigecycline or telavancin
Linezolid causes
thrombocytopenia
daptomycin causes
myopathy and rising CPK
Antibiotics for MRSA, minor infection?
TMP/SMX
clindamycin
doxycycline
Antibiotics to use with penicillin allergy
cephalosporins with rash
Antibiotics for staph with anaphylaxis?
Macrolides (azithromycin, clarithromycin) or clindamycin
Antibiotics for severe infection and penicillin allergy?
vancomycin, linezolid, daptomycin, telavancin
Antibiotics for minor staph infection penicillin anaphylaxis allergy?
macrolides (azithromycin, clarithromycin), clindamycin, TMP/SMX
What is telavancin?
bacterial lipopolysaccharide
What is the mechanism for telavancin?
It inhibits bacterial cell wall synthesis by binding to the D-Ala-D-Ala terminus of the peptidoglycan in the growing cell wall
What is the mechanism for ceftaroline?
inhibits cell wall growth by binding the penicillin binding protein
Linezolid mechanism
inhibits protein synthesis
TMP/SMX mechanism
folate antagonist
Medications specific for streptococcus
penicillin, ampicillin, amoxicillin
What are the gram negative bacilli?
Escherichia coli Enterobacter Citrobacter morganella pseudomonas serratia
Cephalosporins gram negative
cefepime
ceftazidime
penicillins gram negative
piperacillin
ticarcillin
monobactam gram negative
aztreonam
Quinolones gram negative
ciprofloxacin
levofloxacin
moxifloxacin
gemifloxacin
Aminoglycosides gram negative
gentamicin
tobramycin
amikacin
Carbapenems gram negative
Imipenem
meropenem
ertapenem
doripenem
Only carbapenem that does not cover pseudomonas?
ertapenem
Piperacillin and ticarcillin also cover
streptococci and anaerobes
levofloxacin, gemifloxacin and moxifloxacin
excellent pneumococcal drugs
aminoglycosides
work synergistically with other agents to treat staph and enterococcus
Carbapenems cover
streptococcus and all MSSA
Tigecycline covers
MRSA, active gram negative, weaker than other anti-MRSA
4 classes of beta lactam antibiotics
penicillin
cephalosporins
carbapenem
monobactam
best medication for abdominal anaerobes
metronidazole
Carbapenems
piperacillin
ticarcillin
equal in efficacy for abdominal anaerobes compared to metronidazole
cefoxitin
cefotetan
only cephalosporins that cover anaerobes
respiratory anaerobes
clindamycin
Medications with no anaerobic coverage
aminoglycosides aztreonam fluroquinolones oxacillin/nafcillin cephalosporins except cefoxitin and cefotetan
What 3 agents can you choose from for herpes simplex, varicella zoster?
acyclovir
valacyclovir
famciclovir
valganciclovir
ganciclovir
foscarnet
coverage?
CMV and herpes simplex and varicella
what is the best long term therapy for CMV retinitis?
valganciclovir
adverse effects of valganciclovir and ganciclovir?
neutropenia and bone marrow suppression
adverse effects of foscarnet
renal toxicity
What are the oral agents for chronic hepatitis C?
telaprevir
boceprevir
simeprevir
sofosbuvir
which oral agent for chronic hepatitis C does not need to be combined with interferon?
sofosbuvir
Treatment for influenza A and B
oseltamivir
zanamivir
Ribavirin is used for
- Hepatitis C in combination with interferon.
- RSV
What does ribavirin cause?
anemia
What are the treatment options for chronic hepatits B?
lamivudine interferon adefovir tenofovir entecavir telbivudine
What is the mechanism for sofosbuvir?
RNA polymerase inhibitor
What is the mechanism for simeprevir, boceprevir, telaprevir?
protease inhibitor that prevent viral maturation by inhibiting protein synthesis
Fluconazole treatment?
candida, cryptococcus, oral and vaginal candidiasis
Fluconazole will not treat what types of candida?
candida krusei or glabrata
Itraconazole
equal to fluconazole but less easy to use, rarely the best initial therapy
Voriconazole covers
all candida
What is the best agent for aspergillus?
Voriconazole
What is the adverse effect of voriconazole?
some visual disturbance
posaconazole covers
mucormycosis or mucorales
What are the echinocandins?
caspofungin
micafungin
anidulafungin
What is the echinocandins excellent for?
neutropenic fever
Echinocandins does not cover?
Cryptococcus
How does echinocandins compare to amphotericin for neutropenia and fever?
echinocandins are better with less mortality
What are the adverse effects for echinocandins?
they have no significant human toxicity because they affect / inhibit the 1,3 glucan synthesis
What is the mechanism for azole antifungals?
inhibits conversion of lanosterol to ergosterol (major component of the cell wall of fungi)
Amphotericin is effective against what?
all candida, cryptococcus, and aspergillus
What are the last 2 main indications for amphotericin?
cryptococcus
mucormycosis
Aspergillus treatment?
voriconazole
neutropenic fever
caspofungin
adverse effects of amphotericin?
renal toxicity - increased creatinine, hypokalemia, metabolic acidosis, fever, shakes, chills
Amphotericin is directly toxic to?
distal tubules results in RTA
What does distal RTA damage result in?
excess potassium and magnesium loss and hydrogen ion retention
What is the diagnostic test for osteomyelitis?
initial = x-ray 2nd = MRI accurate = bone biopsy and culture
Abnormal bone on x-ray=
must lose more than 50 percent of the calcium
earliest finding of osteomyelitis on an x-ray?
periosteal elevation
What is the best way to follow osteomyelitis response to therapy?
Sedimentation rate
What is the most common cause of osteomyelitis?
direct contiguous spread from overlying tissue
Sensitivity of MRI or bone scan?
they are equal in sensitivity
What does the sensitivity of MRI or bone scan in osteomyelitis mean?
that osteomyelitis can be excluded if they are normal
What is the difference between MRI or the bone scan in osteomyelitis?
MRI is far more specific
What is MRI based on?
Water content
Nuclear bone scan is based on what?
osteoblasts depositing technetium in tissue
How long to treat osteomyelitis with no fever and a normal white cell count?
sedimentation rate, elevated after 4-6 weeks then further treatment and possible surgical debridement
most common cause of osteomyelitis
staphylococcus
treatment for osteomyelitis
oxacillin or nafcillin IV for 4-6 weeks
MRSA is treated with
vancomycin, linezolid, ceftaroline or daptomycin
What are the other causes osteomyelitis?
gram negative bacilli = salmonella and pseudomonas
What is the only form of osteomyelitis that can be successfully treated with oral antibiotics?
salmonella and pseudomonas
What must be done before treating orally?
bone biopsy
What is the treatment plan for chronic osteomyelitis?
you can obtain the biopsy, move the clock forward and treat what you find on the culture
How does otitis externa present?
with itching and drainage from the external auditory canal
What is otitis externa a form of?
its a form of cellulitis of the skin of the external auditory canal
What is otitis externa associated with?
swimming
Why is otitis externa associated with swimming?
it washes out the acidic environment normally found in the external auditory canal
Any diagnostic test for otits externa?
no specific tests
diagnosis is based on exam
What is the treatment for otitis externa?
ofloxacin
ciprofloxacin
polymyxin/neomycin
- add topical hydrocortisone to decrease swelling and itching
If the otitis externa topical treatment what else might be added?
adding acetic acid and water soulution to reacidify the ear can help eliminate the infection
What is the function of cerumen?
make the external auditory canal acidic
what is the function of acid wax in the ear?
acid wax suppresses bacteria - cerumen blocks water and pseudomonas likes to grow in water
What is malignant otitis externa?
its really osteomyelitis of the skull from pseudomonas in a patient with diabetes
What might otitis externa lead to?
it might lead to a brain abscess and destruction of the skull
What is the diagnostic test for malignant otitis externa?
initial is CT or MRI
What is the most accurate test for malignant otitis externa?
biopsy
What is the treatment for malignant otitis externa?
surgical debridement and antibiotics active against pseudomonas
What are some antibiotics active against Pseudomonas?
ciprofloxacin piperacillin cefepime carbapenem aztreonam
How do quinolone antibiotics work?
by inhibiting DNA gyrase (topoisomerase)
DNA gyrase
unwinds DNA so it can be replicated
What are the key features of otitis media?
redness bulging decreased hearing loss of light reflex immobility of the tympanic membrane
Diagnostic testing for otitis media?
no radiologic test
What is the best initial treatment for otitis media?
amoxicillin for 7-10 days
longer for younger patients and shorter for older patients
What is the next step after amoxicillin for otitis media?
perform the most accurate = tympanocentesis and aspirate of the tympanic membrane for culture - rarely necessary
What is otitis media caused by?
Caused by swelling of the Eustachian tube - narrowest portion - isthmus - becomes inflammed, it blocks the egress of secretions
What are the most common causes of otitis media?
pneumococcus
nontypeable Haemophilus
Moraxella
What do you do if otitis media does not improve on amoxicillin after 3 days?
amoxicillin-clavulanate cefdinir ceftibuten cefuroxime cefprozil cefpodoxime
What are the causes of sinusitis?
Viral is most common
Bacterial are streptococcus pneumoniae, H. influenzae and Moraxella catarrhalis
What is the diagnostic test for sinusitis?
X-ray
What is the most accurate test for sinusitis?
sinus aspirate for culture
What is the treatment for sinusitis?
amoxicillin/clavulanate if there is fever and pain, symp despite 7 days of decongestants and purulent nasal discharge
What do you add for sinusitis?
add inhaled steroids
What is clavulanic acid?
beta lactamase inhibitor
What is the mechanism for clavulanic acid?
the enzyme destrys the clavulanic acid instead of the penicilllin
What is the diagnosis for pharyngitis?
pain/sore throat, exudate, adenopathy, no cough/hoarseness
What is the diagnositic test for pharyngitis?
rapid strep test
What is the most accurate test for pharyngitis?
culture
What is the treatment for pharyngitis?
-penicillin or amoxicillin
What is the treatment for pharyngitis in a penicillin allergy patient?
azithromycin
clarithromycin
-use cephalexin if allergy is a just a rash
Patient presentation for influenza
arthralgia myalgia cough headache fever sore throat feeling of tiredness
What is the diagnostic test for influenza?
viral rapid antigen detection - testing a nasopharyngeal swab
What is the treatment for influenza?
oseltamivir or zanamivir
