Infectious Disease - Academic Week Lecture Flashcards
What abx can you use to treat Staphylococcus aureus?
Clindamycin
Cloxacillin
Vancomycin
Cephalexin
*all have gram + coverage
What pathogen causes Streptococcal pharyngitis?
Streptococcus progenies (Group A strep)
A homeless person presents to the ER with a 3 month hx of recurrent, painful, self draining skin abscesses. What is the most likely pathogen?
MRSA
“Grape like clusters”
Staphylococci
“chains”
Streptococci
Catalase +, coagulase + gram positive cocci
Catalase +, coagulase - gram positive cocci
S. aureus
S. epidermidis
Catalase -, Beta hemolytic
S. pyrogens (GAS)
S. agalactiae (GBS)
What infections are caused by Staphylococcus aureus?
SSTI: impetigo, cellulitis, folliculitis, furnaces, carbuncles
Pneumonia, pulmonary abscesses
Endocarditis, meningitis, joint/bone
What toxin mediated reactions are caused by Staphylococcus aureus?
Food poisoning
Scalded Skin Syndrome
Toxic Shock Syndrome
What antibiotics can be used to treat MSSA?
Cloxacillin Cefazolin (Ancef) Cephalexin (Reflex) Vancomycin Clindamycin
What antibiotics can be used to treat MRSA?
Vancomycin TMP/SMX Clindamycin Linezolid Daptomycin
What infections are caused by Group A Strep?
Pharyngitis
Impetigo
Erysipelas
Cellulitis
What toxin mediated reactions are caused by Group A strep?
Necrotizing Fasciitis
Scarlet Fever
Toxic Shock Syndrome
What immune mediated diseases are caused by Group A strep?
Glomerulonephritis
Rheumatic fever
What is the treatment for Necrotizing Fasciitis?
Surgical debridement
IV Pen G
IV Clindamycin
IVIG
What infections can be treated with Pen G?
The Big 3:
- Streptococci
- Neisseria meningitidis
- Treponema pallidum (syphilis)
Plus others (C Diff)
What infections can be treated with ampicillin?
Pen G coverage +:
Enterococci, Listeria
H Flu
Ecoli, Proteus, Shigella, Salmonella
What infections can be treated with Piperacillin?
Amp coverage +: Klebsiella, Sebratia, Enterobacter, Citrobacter Pseudomonas B. fragilis MSSA
What infections can be treated with Cloxacillin?
Only covers gram +
MSSA (not MRSA)
S. Epidermis
Strep Species
(no gram neg-, no anaerobic)
What bugs cause community acquired pneumonia (CAP)?
Streptococcus pneumonia (typical)
Chlamydia (atypicals)
Mycoplasma
Legionella
What is used for out patient treatment of CAP (no modifying factors)?
Azithromycin
2nd line: doxy
What is used for out patient treatment of CAP?
COPD, no steroids past 3 months
Azithromycin, clarithromycin
2nd line: doxy
What is used for out patient treatment of CAP?
COPS, abs or steroids past 3 months
Levofloxacin, moxifloxacin
2nd line: amoxi/clav
Are macrolides good drugs for in or out patient care?
Out patient
(bacterial static - bind to 50S ribosomal subunit inhibiting protein synthesis) … wouldn’t use for someone septic
What is Roseola infantum caused by?
Human herpesvirus 6 (HHV-6)
How do you treat Herpes Zoster infection?
Treat with antivirals within 72 hours of onset:
Acyclovir
Valacyclovir (Vatrex)
Famciclovir (Famvir)
If there are herpes zoster lesions on the tip of the nose, what do you have to worry about?
Corneal involvement
What causes athlete’s foot?
Dermatophyte Trichophyton rubrum
Erythema infectious (fifth disease or slapped cheek disease) is caused by what
Human parvovirus B19
What viruses are DNA viruses?
All the Herpes viruses HPV ONLY Hep B Pox viruses (i.e. molluscum) Adenoviruses Parvovirus B19
(rest are RNA - Hep A,C,E, etc)
A 12 year old boy presents with fever and bilateral parotid enlargement, the most likely diagnosis is:
MUMPS!
note: patients need isolation, transmitted via droplet nuclei or direct contact
What is the Ontario MMR vaccination schedule?
12 months, 4-6 years
What viruses are most commonly involved in pharyngitis?
Adenovirus
X-ray lateral neck = thumbprint sign
Epiglottitis
What pathogens cause epiglottis?
Kids: H. influenza (more nontypel since vaccine); S. pneumonia
Adults: Group A Strep, H flu
What is the treatment for Epiglottis?
Maintain airway #1 concern
Ceftriaxone or Cefotxime
8 year old boy presents to the ER with a maculopapular rash associated with some cough, coryza, fever 39.0
Koplik’s spots on palate after day 3
Measles
What are complications of Measles?
Otitis media blindness pneumonia diarrhea encephalitis 1/1000 death 1/1000
What kind of bacteria is Bordetella pertussis?
Gram negative coccobacillus
What is the treatment for whooping cough?
Azithromycin or clarithromycin (up to 8 weeks into the cough)
Subcutaneous nodule at injury site with associated nodular lymphangitis which appears up to 6 months is seen in:
Sporotrichosis
see spreading up lymphatics
Child age 4 presents with fever, unilateral ear pain, bulging tympanic membrane for 24 hrs. What is the #1 cause bacteria?
Streptococcus pneumoniae
Treatment for acute otitis media?
Amox or amoxi/clav
What is the most common cause of empyema?
Pneumococcus (streptococcus) pneumoniae
A 10 year old girl with a new kitten has a large tender lymph node under the right axilla, otherwise well. Dx?
Acute bartonella henselae infection
Pathogens for the following cat exposure diseases:
Cat scratch
Cat feces
Cat bite
Cat scratch = bartonella
Cat feces = toxoplasmosis
Cat bite = pasturella
An HIV + patient presents with dysphagia and thrush
Oral-esophageal candidiasis
What is the txt for oral-esophageal candidiasis?
Oral fluconazole
At what CD 4cell count do you start prophylaxis against Pneumocystis jiroveci (carinii) in HIV patients?
200 cells/ml
What drug is used for prophylaxis against pneumocystis jiroveci (carinii) in HIV infected patients?
Trimethoprim sulfamethoxozole
When should antiretroviral medication begin in asymptomatic HIV patients at? (CD4 count)
ANY CD4 count
old cut off was 500 cells/ml
A 37 to male IV drug user presents to the ER. The nurse attending suffers a needlestick injury from the patient. Which infection carries a risk of 0.3% overall risk?
HIV
What is the risk of perinatal HIV transmission in untreated HIV + women?
25% overall risk
What is the risk of perinatal HIV transmission in treated HIV + women, stating antiretroviral therapy at 14 weeks gestation, compliant with therapy, and maintains an “undetectable viral load”?
<1%
What is the current antiretroviral treatment standard?
3 drugs one pill/day regimen
Ex: Tenofovir + FTC + Elvitegravir
How do you determine the prognosis for HIV infected patients?
CD4 lymphocyte count and HIV viral load (RNA load)
A 34 year old returns from Zaire Africa 4 days ago with new onset fever, sweats, fatigue. What is your course of action?
Typhoid fever is possible and therefore he needs blood cultures
What common pathogens cause Traveller’s diarrhea?
E coli, Salmonella, Cholera
What antimicrobial agent causes tendinopathy?
Fluoroquinolones
What is the difference in coverage between cipro, levo, and moxi?
Cipro - excellent gram neg + pseudomonas
Levo - gram neg-, gram + and atypical
Moxi - levo + anaerobic
A 67 yo diabetic patient is treated with gentamicin, ceftazidime, and metronidazole for a gangrenous foot infection. She develops acute renal failure 2 weeks into treatment. Why?
Amino glycoside nephrotoxicity
An elderly women is readmitted to the hospital with frequent loose diarrhea after being hospitalized for pneumonia. What is the most likely cause?
Clostridium difficile
Pseudomembranous colitis is caused by:
Clostridium difficile
Clostridium difficile infection is best treated with
Metronidazole orally
Elderly woman is treated with oral metronidazole for her C Diff and relapses with diarrhea. She presented several times to a walk in over 3 month period and was given repeat courses of metronidazole. What is she complaining of now?
Sensory neuropathy
What can you give besides metronidazole for relapsing c diff?
Vanco
A 27 yo female has an ESBL E coli urinary tract infection. What does this mean?
ESBL: extended spectrum beta-lactamase producing
Organism is resistant to cephalosporins
What is the most common cause of peritonsillar cellulitis or abscess?
Beta hemolytic streptococci
What is the most common cause of Ludwig’s angina?
Group A streptococci + anaerobes
How do you treat Ludwig’s angina?
Pen G + metronidazole or clinda
27 year old female presents to ER with a 2 day hx of fever, flank pain, dysuria. Dx?
Pyelonephritis
What is the number one cause of pyelonephritis?
E. Coli
How many days of abx are required for uncomplicated cystitis?
3 days
What are the organisms that cause acute pyelonephritis?
KEEPS Klebsiella E coli Enterococcus Proteus S saphrophyticus
What is the treatment for acute pyelonephritis?
14 days TMP/SMX or 3rd gen ceph or FQ
List Gram Negative Bacilli
Enterobacter (GI tract): E coli Shigella Salmonella Citrobacter Klebsiella Yersinia Proteus Morganella Serrate Enterobacter
H Flu
Pseudomonas
Legionella
etc.
What antibiotics cover PSEUDOMONAS
Cirpo (only oral agent) Aminoglycosides (tobramycin, gent) Ceftazidime / Cefipime Pip/tazo Meropenum Imipenem
What antibiotics cover ANAEROBICs:
Metronidazole Clindamycin Moxiflox Amax/Clav (clavulin) Cefoxitin/ Cefotetan Pip/tazo Meropenum Imipenum
Does a positive mantoux test mean a patient has active TB?
no
Isoniazid hepatotoxicity occurs in what percentage of patients?
1-2% of patients in general
2% over the age of 50
What are the side effects of Isoniazid?
Central nervous system too
Peripheral neuropathy
Hepatotoxicity
Jaundice/ skin rash
What is the overall lifetime risk of developing reactivated TB in a patient with untreated latent TB?
5-10%
A hospitalized patient with active pulmonary TB and coughing requires which infection control measure?
Negative pressure ventilation
What is the difference in treatment between active and latent TB?
Latent: Isoniazid (INH) + Vit B6 x 9 months
Active: add
Rifampin x 9-12 mo
Pyrazinmide x 2 mo
A 26 yo female reports vaginal discharge and lower abdominal pain over the last few days. Examination reveals much-purulent endocervical discharge and gram stain revealing NO organisms. Dx?
Chlamydia trachomatis (doesn’t gram stain, lives IN cells)
What is the best way to dx syphilis?
Serologically
A 22 yo sexually active male presents with urethral discharge and a urine specimen for N gonorrhoea by NAAT is +.
Treatment?
Ceftriaxone 250mg IM x 2dose + Azithro 1 gm PO X 1 dose
Txt for chlamydia
Doxy 100mg PO BID x 7 days
or
Azithro 1gm PO x1
Txt for HPV
Imiquimod 3x/wk
Cryotherapy
Excision/ laser
Txt for treponema pallidum
Benzathine Penicillin
Txt Herpes
Acyclovir 200 mg 5x/d for 5 days
With virus is associated with a hepatoma?
HBV
Close personal contacts of patients with HEP A should receive:
Gamma globulin
Hep A serologies
HAV IgM
HAV IgG
Hep C serologies
Hep C AB
Chronically determined by further testing for Hep C RNA level
Hep B serologies
Hep B AB = past infection or immunization
Anti-Hbc = IgM + (acute infection)
= IgG + (past infection)
HBsAg = acute HBV or chronic carrier HBeAg = chronic active Hep B
A patient presents with diffuse erythema, pain, and warmth of the lower leg with associated intermittent fever. Txt?
Want to cover Gram + (staph and strep)
IV Cefazolin
Skin and soft tissue infection:
Txt for mild, uncomplicated
Cloxacillin, cephazolin, or clinda (pen allergy)
SSTI in diabetic
Add gram neg and anaerobic coverage
SSTI in IV drug use
MRSA (vanco)
SSTI nec fasc
Cephazolin or Pen + Clinda
An 18 yo previously healthy male presents to ER with a one day hx of headache, fever, photophobia. Empiric txt for bacterial meningitis?
IV Ceftriaxone
Meningitis: gram+ diplococci
Streptococcus pneumo
Meningitis: gram neg- diplococci
N. meningitidis
What drug should you add if you suspect Listeria in meningitis?
Ampicillin IV
Organisms for acute meningitis in neonates and <2mon
Ecoli
GBS
Listeria
Organisms for acute meningitis < 10yrs
Viral
H flu
S pneumo
Meningococci
Organisms for acute meningitis in adults
Viral
S pneumo
Meningococci
Organisms for acute meningitis elderly
S pneumo
Gram neg- baci
Listeria
A 50 yo male presents with sudden onset of non bloody watery diarrhea 5 days after returning home from Mexico. dx?
1 cause of travellers diarrhea
Enterotoxigenic E. Coli
Treatment for Enterotoxigenic E. Coli
Levofloxacin
Ciprofloxacin
TMP/SMX
IF travellers diarrhea lasts >14 days consider
Protozoa
What organisms cause bloody diarrhea (invasive, inflam)
Campylobacter jejuni Shigella Salmonella sp Yersinia E Coli 0157:H7
What organisms cause non bloody diarrhea
Enterotoxigenic E Coli
Vibrio cholera
S aureus
C Diff
What are parasitic causes of diarrhea?
Entamoeba histolytic (amebiasis) txt with metronidazole/ iodoquinol if invasive (liver abscess)
Guardia lamblia (bever fever) txt with metronidazole
Cryptosporidium
txt supportive
What viruses cause diarrhea?
Rotavirus
Norovirus
A 2yo female presents with vaginal and perianal pruritis over the last 1 week. Symptoms are transient and usually nocturnal. Dx?
Enterobius vermicularis (pinworms)
A 45 yo male from Northern Ontario was investigated for vague RUQ and RLL discomfort. CXR revealed a multiloculated just in the right lower lung and abdo u/s revealed a large cast with septate internal structures. The patient has extensive involvement with wild animals and dogs. Dx?
Echinococcus granulosus
dog pinworm - makes cysts in liver, lungs
A 60yo male with long standing OA of his knees presents with an acutely inflamed, swollen, painful right knee with difficulty weight bearing. Septic arthritis - what is the route of infection?
Hematogenous
Common causes of septic arthritis?
S. aureus
N. gonorrhoea (75% in sexually active)
How do you make the dx of septic arthritis?
Arthrocentisis
Txt for septic arthritis?
Ceftriaxone + Clinda (empiric) min 4 weeks if native joint
Erythema chronicum migrant is associated with
Lyme disease
How do you dx Lyme disease
serology
Txt Lyme disease
Stage 1: Doxy 21 days
Stage 2,3: Ceftriaxone 2-4 weeks