Abx Dickey Flashcards
Describe molds
Multi-cellular
Reproduce by disseminating spores
Mainly cause invasive dz through inhalation
-pulmonary dz most common, but can disseminate
Describe yeasts
Single-celled
Reproduce by budding
Cause superficial or invasive infections
Describe dimorphic yeasts
Exist as either a yeast or mold, depending on pathogen, site of growth (host vs. lab), and temperature
Give examples of yeasts
Candida
Cryptococcus
Give examples of dimorphic fungi
Histoplasma
Blastomyces
Give an example of a mold
Aspergillus
Which type of fungi is classified one way but acts another?
Cryptococcus is classified as primary (pathogenic), but acts more opportunistic
List pathogenic fungi
Histoplasmosis
Blastomycosis
Cryptococcus
List opportunistic fungi
Candidiasis
Aspergillosis
(Cryptococcus acts opportunistic)
Fungi that may cause dz in both healthy and immunocompromised individuals
Primary (pathogenic) fungi
Histoplasmosis, blastomycosis, and cryptococcosis*
Fungi that generally cause dz in immunocompromised individuals
Opportunistic
Candidiasis, aspergillosis, Cryptococcus*
Types of pts who are immunocompromised:
Diabetes Lymphoreticular/hematologic malignancies Immunodeficiency dz (eg: HIV) Immunosuppressive Therapy -High dose corticosteroids -Immunosuppressants -Antineoplastic agents -Broad spectrum Abx Organ transplants
C. Albicans
50% of candida species
Most virulent
SUSCEPTIBLE to azoles
Candidiasis is usually acquired via
GI tract
May enter bloodstream via indwelling IV catheter
Risk factors for candidemia
Multiple Abx Vascular access Parenteral nutrition ICU stay > 7 days Candida colonization Renal failure Major abdominal surgery
Tx of chronic disseminated candidiasis
Fluconazole or Ampho B (for several weeks followed by transition to fluconazole)
Tx of candidiasis in neutropenic adults
Echinocandin or
Lipid formulation of Ampho B
Tx of candidiasis in nonneutropenic adults
Fluconazole or
Echinocandin
All pts with candidemia need…
An eye exam to rule out Candida endophthalmitis
Treatment duration for candida infxns
14 days after 1st negative culture and signs of clinical improvement
Empiric therapy for candida infxns should be initiated…
Within 4 days or persistent fever unresponsive to Abx; possibly sooner in pts with risk factors present
Name two species of Cryptococcus
C. neoformans
C. gattii
Where does Cryptococcus exist
In soil and pigeon droppings worldwide
How is Cryptococcus infxn acquired?
Through inhalation of the organism
What is the 2nd most common fungal pathogen
Cryptococcus
Primary Cryptococcosis in humans almost always occurs…
In the lungs
Two most common candidiasis species and their susceptibilities:
C. albicans - S to azoles, Echinocandin, & amphoB
C. glabrata - use Echinocandin, R to azoles
Cryptococcus disseminates into…
CSF - meningitis
Tx of Cryptococcus infxn, pulmonary, asymptomatic
Drug tx usually not req’d
Observe
or fluconazole
Tx of Cryptococcus infxn, pulmonary, mild-mod
Fluconazole
Tx of Cryptococcus infxn, pulmonary, severe or inability to take azoles…
Ampho B
Tx of Cryptococcus infxn, CNS, HIV or transplant pt…
3 stages
- Induction - Ampho B plus Flucytosine (more Ampho if renal dysfx or inability to take Flucytosine)
- Consolidation - fluconazole
- Maint. - fluconazole
Tx of Aspergillus infxn…
Voriconazole
Prophylaxis for Aspergillus infxn…
Posaconazole
Tx of mild-mod histo, pulmonary…
If symptoms >4 wks: itraconazole
Tx of mild-mod histo, disseminated…
Itraconazole
Tx of mod-severe and CNS histo, (both pulm and disseminated)…
Ampho B followed by itraconazole
Tx of chronic cavitary pulmonary histo…
Itraconazole
Tx of mild to mod Blastomyces infxn…
Itraconazole
Tx of mod-severe Blastomyces infxn…
Ampho B followed by itraconazole
Presence of viable microorganisms in the blood by a positive culture result is known as…
BSI
Difference between primary and secondary BSI
Primary - no known cause
Secondary - secondary to a localized focus of infxn
Examples of secondary BSI causes
Biliary Tract Infxn
Wound Infxn
Skin / ST Infxn
Pneumonia
List usual contaminants of BSIs…
Coag Neg Staph
Bacillus
Corynebacterium
Propionibacterium
List important Gram (+) clinical pathogens in BSIs…
S. aureus
Strep. pn
Group A Strep
List important Gram (-) clinical pathogens in BSIs…
Enterobacteriaceae Haemophils Pseudomonas aeruginosa Bacteroides species Candida species
Gram pos. clusters, think…
Staph
Gram pos. pairs/chains, think…
Strep or
Enterococci
Empiric tx for gram (+) BSI…
Vancomycin
-cidal
Which organisms are more likely to disseminate more than others?
Gram pos. cocci = Candida»_space;> Gram neg. rods
Tx for MSSA BSI…
Nafcillin, oxacillin, or cefazolin
- Vanc ok if beta-lactam allergy
Tx of MRSA BSI…
Continue Vanc.
-Daptomycin preferred if MIC > 2
Tx of Enterococcus BSI…
Ampicillin
- Vanc. ok if beta-lactam allergy
Tx of Enterococcus- VRE BSI…
Daptomycin
Tx of Streptococcus BSI…
Beta-lactam
- Vanc. ok if beta-lactam allergy
Most frequent bacteria in inpatient BSIs…
S. aureus E. coli Enterococcus CoNS P. aeruginosa
Most frequent bacteria in outpatient BSIs…
E. coli S. aureus Enterococcus P. aeruginosa CoNS
Non-pharm tx of Gram (+) BSI…
Follow up TTE/TEE - see if endocarditis is present
Remove central venous catheter
Which type of BSI should you check for pseudomonas?
Gram Neg BSI
Pseudomonas RFs…
Severe sepsis or septic shock present Immunocompromised ICU Recent pseudomonas infxn Recent hospitalization Long-term hemodialysis Nursing home Recent IV Abx Recent chemotherapy
Tx of Gram Neg. BSI if pseudomonas suspected…
Two drugs with two different MOAs:
- cell wall agents
- piper/tazo -aztreonam
- ticar/clavu -meropenem
- ceftazidime -imipenem/cilastin
- cefepime -doripenem
- Aminoglycosides
- gent, tobra, or amikacin
- FQLs
- cipro or levofloxacin
Tx of ESBL BSI…
Empiric tx with Carbapenems
- imipenem/cilastin
- meropenem
- doripenem
- ertapenem
Tx of Gram Neg. BSI when suspecting pseudomonas and ESBL…
Carbapenem (for ESBL) PLUS either
-aminoglycoside or
-FQL
(2 drugs - 2 MOAs for pseudomonas)
ESBL RFs…
Previous ESBL infxn
ICU
Failure to improve on other BS Abx
Previous hospitalization w/in last 3 months
Exposure to cephs, carbs, or FQLs w/in 30 days
Extensive hospital or ICU stay
Recurrent UTIs
Chronic catheter
Hemodialysis
Urosepsis based on local sensitivities for ESBLs
Non-pharm tx for Gram (-) BSIs…
Remove central venous catheters
Tx DUR for all BSIs…
14 days after neg. culture & signs of improvement
- maybe shorter for enterococcus