Infectious Diseases Flashcards
what are first line oral and IV antibiotics for MSSA?
oral: dicloxacillin, cephalexin, cefadroxil
intravenous: oxacillin, nafcillin, cefazolin
what are first line oral and intravenous antibiotics for MRSA?
oral: linezolid, septrin, doxycycline
IV: vancomycin, linezolid, daptomycin, ceftaroline, oritavancin, telavancin, dalbavancin
adverse effects of linezolid?
thrombocytopenia
interaction with MOA-I
adverse effects of daptomycin?
increases serum CK
not effective against LRTI
how do you treat minor skin/soft tissue infections of MRSA?
septrin, doxy, clindamycin, linezolid
what is amoxicillin used as first-line therapy for?
- otitis media
- endocarditis prophylaxis in dental infection
- UTIs in pregnancy (or nitrofurantoin)
- lyme disease (limited to rash, arthralgia and CN VII involvement)
- listeria monocytogenes
- enterococcus infection
which is the only cefalosporin that will cover MRSA?
ceftaroline
which groups of bacteria are resistant to cephalosporins?
MRSA (only caftaroline works), ESBLs, listeria, enterococcus
how do you treat ESBLs?
what is the second-line?
carbapenems
polymixin is used if the ESBL is resistant to carbapenems. care for nephrotoxicity
also cephalosporins with beta-lactamase combinations:
- ceftolazone/tazobactam
- ceftazidime/avibactam
if your patient has a rash to penicillins, are cephalosporins safe for use?
yes
only if the reaction is anaphylaxis will you have to avoid cephalosporins (should use non-beta-lactam antibiotics for these)
what infections is defaloxacin used for?
MRSA skin infections
Gram-negative rods
what is the first-line for CAP?
third-generation cephalosporins with macrolide
cefotaxime/ceftriaxone + erythro/clarithro/azithro
what is the treatment for Lyme disease involving the brain/heart?
ceftriaxone
what is the first-line for gonorrhoea?
ceftriaxone
which population do you have to avoid ceftriaxone and why?
neonates due to impaired biliary metabolism
use cefotaxime instead
what is the difference in treating ventilator-associated pneumonia versus normal CAP?
use ceftaroline (4th gen) as is has better coverage against staphylococcus
how is ertapenem different from the other carbapenem antibiotics?
does not have any anti-pseudomonal coverage
in diverticulitis, which is the best floroquinolone? what do you have to consider for the others?
moxifloxacin is the only one that covers anaerobes and can be used as a single agent
cipro/levo/gemi - need to add metronidazole
which antibiotics are associated with achilles tendonitis/tendon rupture?
fluroquinolones
which antibiotics are associated with bone growth abnormalities in children and pregnant women?
fluroquinolones
what is the treatment for syphillis in pen-allergy?
doxycycline
what are the most common gram-negative bacteria?
- E coli
- Klebsiella
- Proteus
- Pseudomonas
- Citrobacter
- Enterobacter
in what setting would you get a staphylococcus meningitis?
following neurosurgery
what are the typical organisms for bacterial meningitis?
streptococcus pneumoniae, haemophillus, neisseria, listeria
what are the precautions that must be taken for somebody with Neisseria infection?
rifampin, ciprofloxacin or ceftriaxone for close contacts
respiratory isolation
what is the most rapid onset gastroenteritis that is associated with wheeze and flushing?
scromboid, found in fish
treat with antihistamines
which pathogens give bloody stool appearance?
E coli, shigella, campylobacter, yersinia
how do you treat cryptosporidia diarrhoea?
treat the underlying AIDS
nitazoxanide
what is the nucleic acid structure of HBV and HCV?
HBV - DNA
HCV - RNA
how do you treat hepatitis C?
sofosbuvir and ledipasvir for genotype 1
what are the side-effects of interferon?
myalgia + athralgia
leukopenia + thrombocytopenia
flu-like symptoms, depression
which antiviral covers all genotypes of HCV?
velpatasvir
in hepatitis C, what is the relevance of the following tests:
- PCR/viral load
- genotype
- liver biopsy
- PCR - anyone with a detectable viral load needs treatment
- genotype - predicts the response for treatment.
- Genotype 1 is treated with sofosbuvir and ledipasvir
- all genotype can be treated with sofosbuvir and velpatasvir
- liver biopsy - assess the extent of fibrosis. if they have detectable viral load then you do not need liver biopsy as you will treat with antivirals anyway
what is the difference in treatment between older and younger men with epididymoorchitis?
younger - ceftriaxone and doxycycline
older - septrin or a quinolone (as if it were a UTI)
what is the treatment for PID as inpatient and outpatient?
IP: cefoxitin and doxycycline
OP: ceftriaxone and doxycycline (with metronidazole)
pen-allergic: levofloxacin and metronidazole
what is the treatment for lymphogranuloma venerium and chancroid?
LGV - doxycycline
chancroid - azithromycin
which cerebral infection in immunocompromised patients is associated with indolent presentation, no meningism and elevated CSF pressure?
cryptococcus
diagnosed with CSF serology, india ink stain or culture on Sabouraud medium
which species are viridans group streptococcus?
S sanguinis, S milleri, S mitis, S mutans, S sobrinus, S oralis
which are the common live vaccines?
varicella and zoster, intranasal influenza, MMR
what are elevated LDH levels in pneumonia significant for?
PCP pneumonia
what pathogen causes ecthema gangrenosum?
invasion of the vasculra media and adventitia leading to ischaemic necrosis, indurated pustules/bullae and eventually gangrenous ulcers
pseudomonas aeruginosa
only in immunocompromised individuals
what is the treatment for HIV cryptococcal meningitis?
initial: amphotericin B and flucytosine (2 weeks)
maintenance: fluconazole (8 weeks)
what is the finding on urinalysis that would suggest proteus infection?
urinary pH > 8
a fungal infection in the southwestern US, lung, skin and meningies
coccidiodiomycosis
a fungal infection from the Great Lakes, Mississippi river and Ohio river basins presenting with lung, skin and lytic bone lesions?
Blastomycosis
what antimicrobials and at what CD4 level should be started in HIV for prophyaxis against opportunistic infections?
200 - septrin for PCP
150 - itraconizole for histoplasmosis (endemic area)
100 - septrin for toxoplasma gondii (or pyrimethamine/leucovorin)
50 - azithromycin for MAC
what is the emergency treatment for bacterial meningitis?
when would you add ampicillin?
ceftriaxone, vancomycin and steroids
age > 50 or risk factors for listeria
who needs a sequential pneumococcal vaccine and who gets the PCV23 alone?
healthy, younger than 65 gets PCV23 only
sequential:
- older than 65
- CSF leaks, cochlear implants
- immunosupressed, sickle cell disease, asplenia
- CKD
how do you treat Norcardia?
when do you need to add something to standard therapy?
septrin usually for 6-12 months
surgical drainage of the abscess
if CNS involvement, add carbapenem
endocarditis + colonic neoplasia
Strep gallolyticus (S bovis type 1)
opportunistic infection giving cough, dyspnoea, mucocutaneous lesions/mouth ulcers, infiltrates in the lung, lymphadenopathy and hepatosplenomegaly, pancytopenia
how do you treat it?
histoplasmosis
IV amphotericin B for 2 weeks then maintenance therapy with itraconazole for 1 year
how do you treat actinomyces?
penicillin for 2-6 month
periorbital oedema, myositis and eosinophillia
trichinellosis
when is doxycycline contraindicated?
what can you give for lyme disease instead?
children younger than 8
pregnant or lactating women
skin papule that ruptures with nonpurulent, odorless discharge then leading to further lesions around the proximal lymphatic drainage?
what’s the treatment?
sporothrix schenckii
itraconazole 3-6 months
what commonly causes erysipelas?
Group A strep (pyogenes)
what causes epidydimoorchitis in men > 35 years most commonly?
E coli
how do you manage a tick that is still attached to the patient?
remove with forceps as close to the skin as possible
if tick is on for >36 hours then give antimicrobial prophylaxis with single dose doxycycline
chronic, slow-growing, non-tender mass near the mandible with multiple sinus tracts draining yellow granules
how do you treat?
actinomyces
penicillin 2-6 months, ?surgery
how do you diagnose babesiosis?
blood film microscopy looking for intracellular Maltese cross protozoon
what reaction to tuberculin skin test in HIV is considered positive?
> 5 mm in all patients
treat with 9 months isoniazid-pyridoxine for latent TB
treat with RIPE for active TB (symptoms, radiologic findings on CXR)
what are the prophylactic medications for malaria?
- mefloquine
- atovaquone-proguanil
- doxycycline
to be given 2 weeks before going and up to 4 weeks after return
what is the treatment for latent tuberculosis?
isoniazid for 9 months
give pyridoxine as well to prevent peripheral neuropathy
who should you treat for TB if induration is 5-10 mm
HIV positive
immunosuppressed/organ transplant
known recent TB exposure or signs of healed TB on CXR
