Abx Dickey Flashcards by BJ Jar

Describe molds

Multi-cellular
Reproduce by disseminating spores
Mainly cause invasive dz through inhalation
-pulmonary dz most common, but can disseminate

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Describe yeasts

Single-celled
Reproduce by budding
Cause superficial or invasive infections

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Describe dimorphic yeasts

Exist as either a yeast or mold, depending on pathogen, site of growth (host vs. lab), and temperature

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Give examples of yeasts

Candida

Cryptococcus

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Give examples of dimorphic fungi

Histoplasma

Blastomyces

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Give an example of a mold

Aspergillus

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Which type of fungi is classified one way but acts another?

Cryptococcus is classified as primary (pathogenic), but acts more opportunistic

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List pathogenic fungi

Histoplasmosis
Blastomycosis
Cryptococcus

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List opportunistic fungi

Candidiasis
Aspergillosis
(Cryptococcus acts opportunistic)

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Fungi that may cause dz in both healthy and immunocompromised individuals

Primary (pathogenic) fungi

Histoplasmosis, blastomycosis, and cryptococcosis*

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Fungi that generally cause dz in immunocompromised individuals

Opportunistic

Candidiasis, aspergillosis, Cryptococcus*

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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

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C. Albicans

50% of candida species
Most virulent
SUSCEPTIBLE to azoles

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Candidiasis is usually acquired via

GI tract

May enter bloodstream via indwelling IV catheter

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Risk factors for candidemia

Multiple Abx
Vascular access
Parenteral nutrition
ICU stay > 7 days
Candida colonization 
Renal failure
Major abdominal surgery

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Tx of chronic disseminated candidiasis

Fluconazole or
Ampho B (for several weeks followed by transition to fluconazole)

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Tx of candidiasis in neutropenic adults

Echinocandin or

Lipid formulation of Ampho B

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Tx of candidiasis in nonneutropenic adults

Fluconazole or

Echinocandin

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All pts with candidemia need…

An eye exam to rule out Candida endophthalmitis

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Treatment duration for candida infxns

14 days after 1st negative culture and signs of clinical improvement

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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

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Name two species of Cryptococcus

C. neoformans

C. gattii

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Where does Cryptococcus exist

In soil and pigeon droppings worldwide

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How is Cryptococcus infxn acquired?

Through inhalation of the organism

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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 1. Induction - Ampho B plus Flucytosine (more Ampho if renal dysfx or inability to take Flucytosine) 2. Consolidation - fluconazole 3. 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 >>> 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: 1. cell wall agents - piper/tazo -aztreonam - ticar/clavu -meropenem - ceftazidime -imipenem/cilastin - cefepime -doripenem 2. Aminoglycosides - gent, tobra, or amikacin 3. 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