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Empiric Antifungal Therapy in the ICU. Ramzi Moufarrej, M.D Chief of Critical Care Zayed Military Hospital / Abu Dhabi. Invasive fungal infections have increased significantly over the last 2 decades. aging population with life sustaining therapies like renal dialysis

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Empiric Antifungal Therapy in the ICU

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Empiric antifungal therapy in the icu l.jpg

Empiric Antifungal Therapy in the ICU

Ramzi Moufarrej, M.D

Chief of Critical Care

Zayed Military Hospital / Abu Dhabi


Introduction l.jpg

Invasive fungal infections have increased significantly over the last 2 decades.

aging population with life sustaining therapies like renal dialysis

broad spectrum antimicrobial therapy and invasive medical devices

bone marrow transplantation (BMT) & solid organ transplantation (SOT)

intensive chemotherapy for malignancies

HIV/AIDS epidemic.

Introduction


Risk for invasive mycosis l.jpg

Non-Neutropenic related to barrier breakdown, change in colonization.

Acute renal failure (RR 4.2)

Parenteral nutrition with intralipid (RR 3.6)

Prior surgery specially GI (RR 7.3)

Indwelling central line ? Triple lumen (RR 5.4)

Broad spectrum antibiotics

Diabetes

Burns

Mechanical Ventilation

Steroids

Neutropenic related to above plus immune cell suppression and underlying malignancy.

Severe immunosuppressive: BMT or SOT

Risk for Invasive Mycosis

National Epidemiology of Mycosis Survey (NEMIS) was a prospective, multicenter study conducted at 6 US sites from 1993–1995 to examine rates of risk factors for the development of candidal bloodstream infections (CBSIs) among patients in surgical and neonatal intensive care units >48 hours. Among 4276 patients, 42 CBSIs occurred.

Adapted from Blumberg HM et al, and the NEMIS Study Group Clin Infect Dis 2001;33:177–186; Garber G Drugs 2001;61(suppl 1):1–12.


Invasive mycosis l.jpg

Invasive Mycosis

Aspergillosis

Candidiasis

SOT or BMT

MICU or SICU

Oncology

Barrier immunity

Barrier plus cellular immunity

Decreasing immunity


Treatment of invasive mycosis l.jpg

Polyenes

Amphotericin B (AmB) or Liposomal AmB (kidney toxicity)

Azoles

Fluconazole 400-800 mg/day (liver toxicity, CYP450)

Voriconazole (liver toxicity, visual disturbances, CYP450)

Posaconazole (liver toxicity, CYP450)

Echinocandins

Caspofungin iv (liver toxicity)

Combination ex. AmB/ Fluconazole (liver, kidney toxicity)

Choice of agents depends on whether the patient on previous azole prophylaxis, culture results, local fungal sensitivity, colonization, renal or liver disease, presence of drug-drug interactions, presence of hardware, immuno -suppresion, site of disease ex. urine.

Treatment of Invasive Mycosis


Site of action of selected anti fungal agents l.jpg

Adapted from Andriole VT J Antimicrob Chemother 1999;44:151–162; Graybill JR et al Antimicrob Agents Chemother 1997;41:1775–1777; Groll AH, Walsh TJ Expert Opin Invest Drugs 2001;10(8):1545–1558.

Site of Action of Selected Anti-fungal Agents

Cell membrane

Polyenes AmB (sterols)

Azoles Fluconazole (CYP450)

Cell wall

Echinocandins Caspofungin (Glucan synthesis inhibitors)


Focus on candidiasis l.jpg

Focus on Candidiasis

  • Invasive Candida infections:

    • 4th most common nosocomial bloodstream infection in the USA with mortality approaching 40% in line related candidemia*

Pathogen No. of Isolates Incidence (%)

Coagulase-negative staphylococci390831.9

Staphylococcus aureus192815.7

Enterococci135411.1

Candida species9347.6

*In a 3-year (1995–1998) surveillance study of 49 hospitals in the United States.

Adapted from Edmond MB et al Clin Infect Dis 1999;29:239–244; Andriole VT JAntimicrob Chemother 1999;44:151–162; Uzun O, Anaissie EJ Ann Oncol 2000;11:1517–1521.


Slide8 l.jpg

Species of Candida Most Commonly Isolated in Bloodstream Infections

In an international surveillance study 1997-1998:

C. krusei

2%

other Candida spp 5%

C.tropicalis

8%

C. albicans

54%

C.parapsilosis

15%

C.glabrata

16%

Adapted from Pfaller MA et al and The SENTRY Participant Group Antimicrob Agents Chemother 2000;44:747–751.

Since then increase in Candida spp. with higher incidence of fluconazole resistance.

Snydman DR. 2003. Chest 123(Suppl 5):500S-503S). Garbino J. et al. 2002. Medicine;81:425-433.


Invasive candidiasis in the icu l.jpg

Common in the ICU (9.8/1000 admissions) with high morbidity (increased LOS ~22 days) & mortality (~ 30-40%) resulting in increased cost (~ $44,000/ episode).

Difficult to diagnose (cultures positive in only ~ 50%).

We can define ICU risk factors for candidiasis and target the population at highest risk with empiric Rx.

Recent increase in Candida spp. resistant to Diflucan.

Advances in antifungal therapy have resulted in agents, like echinocandins and triazoles, with high activity, a broad spectrum, and low toxicity ideal for empiric therapy and combination therapy options.

Invasive Candidiasis in the ICU

Prophylaxis and treatment of invasive candidiasis in the intensive care setting.

Eur J Clin Microbiol Infect Dis. 2004:23; 739-744.


Major risk factors l.jpg

Prior antibiotic use, central venous catheters, total parenteral nutrition, major surgery within the preceding week, steroids, dialysis and immunosuppression.

Intensive care unit length of stay is an important risk factor, with the rate of infections rising rapidly after 7-10 days.

Major Risk Factors

Dimopoulos G, et al. Candidemia in immunocompromised and immunocompetent critically ill patients: a prospective comparative study. Eur J Clin Microbiol Infect Dis. 2007


Risk factor selection l.jpg

Risk Factor Selection

Fever

Underlying

disease

Infection

Selection

Antibiotics

Skin or

mucosa

damage

Malignancy

Diabetes

Renal disease

CTD on steroids

Malnutrition on TPN

Mechanical Ventilation > 48h

Burns

Colonization

Instruments

CV Catheter

Knife


Invasive candidiasis after colonization and bacteremia l.jpg

Invasive Candidiasis After Colonization and Bacteremia

81 patients

Bacteremia

NO 46

YES 35

- + +++

14 24 8

- + +++

7 13 15

Colonization

Acute

Invasive

Candidiasis

018

100

53%

Guiot et al. CID.1994;18:525-32


Laboratory diagnosis l.jpg

Microbiology methods:

Recovery of Candida species from sterile sites (ex. blood, peritoneal fluid) is diagnostic of IC and recovery from multiple non-sterile sites is highly suggestive of IC in the at-risk patient.

Blood culture is positive in less than 50% of patients with autopsy proven IC.

Molecular methods:

early identification ex PNA FISH

Serological methods:

early diagnosis ex. 1,3 beta D glucan assay.

Histopatholgic methods.

Laboratory Diagnosis


Clinical diagnosis l.jpg

The clinical manifestations of IC are nonspecific, but may include:

Fever and progressive sepsis with multi-organ failure despite antibiotics.

Invasive candidiasis (IC) related cutaneous lesions.

Macronodular rash frequently confused with drug allergies. A biopsy of the deeper layers of skin particularly the vascularized areas and the dermis is important.

Ophthalmic lesions (Candida endophthalmitis).

A fundoscopic evaluation for the presence of Candida endophthalmitis should be performed in patients with candidemia.

Clinical Diagnosis


Therapy of ic in the icu l.jpg

A definitive diagnosis of IC may be delayed when the clinical and laboratory tools readily available to clinicians are used to assess patients for Candida infection.

A delay in diagnosis will unfortunately result in a delay in initiation of antifungal therapy, which is associated with increased mortality*.

Therefore, in the patient with suspected Candida infection, treatment may need to be initiated on the basis of individual patient factors before a definitive diagnosis is made.

Therapy of IC in the ICU

*Morrel M et al. 2005. Antimicrob Agents Chemother. 49(9): 3640-5.

*Garey K et al. 2006. Clin Infect Dis. 43: 25-31.


Can we wait for the blood culture results in candidemia l.jpg

Retrospective cohort analysis 1/2001-12/2004: N=157 patients with candidemia.

Delay in empiric Rx of candidemia till after blood cultures turn positive resulted in higher mortality.

Start of anti-fungal Rx >12 hrs of drawing a blood culture that turns positive had AOR= 2.09 for mortality, p=0.018.

Can we wait for the blood culture results in candidemia?

Morrel M et al. 2005. Antimicrob Agents Chemother. 49(9):3640-5


Treatment of suspected invasive candidiasis definitions l.jpg

Prophylactic therapy:protective or preventive therapy given to everyone in a given class (ex. BMT patients who are at very high risk for IC).

Preemptive therapy:therapy given to deter or prevent anticipated infection; patients at risk are monitored closely and therapy is initiated with early evidence suggesting infection (ex. positive Candida cultures at non-sterile sites, clinical suspicion) with the goal of preventing disease.

Empirical therapy: therapy guided by practical experience and observation, but with nonspecific evidence in a given patient (ex. therapy is started because a cancer patient has remained febrile after several days of broad-spectrum antibiotics).

Directed therapy: is based on a clinical or laboratory finding indicating that an infection is present (ex. positive blood culture for Candida species).

Treatment of Suspected Invasive Candidiasis (Definitions)


Timing of intervention l.jpg

Timing of Intervention

Directed

Empiric

infection

specific symptom

Pre-emptive

refractory fever

Prophylactic

aspecific symptom ± early markers

suppressive Rx

basic disease

Progression


Prophylactic preemptive or empiric use of anti fungals l.jpg

PROS

High Mortality

Difficulty in Diagnosis

Undetected Infection

Reduced systemic mycoses and improved mortality with prophylaxis

CONS

Toxicity

Expense

Diagnosis not certain

Too much treatment without infection

Too little treatment with infection

Prophylactic, Preemptive or Empiric Use of Anti-fungals


Fluconazole prophylaxis and colonization of neutropenic patients l.jpg

Fluconazole Prophylaxis and Colonization of Neutropenic Patients

Winston et al. Ann Intern Med. 1993;118:495-503


Candida prophylaxis in the surgical icu patients with high risk for candidemia l.jpg

Eggiman et al. 1999. CCM 27: 1066-1072.

Fluconazole reduced candida peritonitis and colonization in 43 patients with complicated GI surgeries. High risk patients ? Was it preemptive therapy.

Pelz et al. 2001. Ann Surg. 233: 542-548.

Fluconazole reduced candida infection in critically ill surgical patients in SICU > 3 days. No mortality benefit.

Predictors included: APACHE II score, fungal colonization, TPN, days to first dose of prophylactic drug.

Paphitou et al. 2005. Med Mycol. 43(3):235-43.

327 patients in SICU > 3 days were reviewed to identify predictive factors.

Combination of DM, HD, TPN, broad-spectrum antibiotics had an invasive candidiasis rate of 16.6% versus a 5.1% rate for patients lacking these characteristics (P = 0.001). The rule captured 78% of patients with IC.

Candida prophylaxis in the Surgical ICU(patients with high risk for candidemia)


Candida prophylaxis in micu sicu mv 48h expected los 72h l.jpg

Candida Prophylaxis in MICU & SICU (MV > 48h & expected LOS > 72h)

Incidence of IC=5.8%

Incidence of IC=16%

Garbino et al. Intensive Care Med. 2002;28:1708-17


Summary candida prophylaxis l.jpg

Prophylaxis is effective in the highest risk patients.

Prophylaxis reduces the incidence of IC.

A positive impact on mortality has not been shown except in severely immunocompromised hosts (neutropenia, BMT, or solid organ transplantation).

Distinction between prophylactic & preemptive therapy needed specially in ICU. Risk ? Dose?.

Summary (Candida Prophylaxis)


Assessment of preemptive treatment to prevent severe candidiasis in sicu l.jpg

Before/after intervention study (2 years prospective & historical)

Systematic mycological screening on all patients admitted to the SICU ≥ 5 days, immediately at admittance and then weekly until discharge. Patients with colonization index ≥ 0.4 (used to assess intensity of mucosal colonization) received early preemptive antifungal Rx (fluconazole IV 800mg, then 400 mg/day for 2 wks).

Candida infections occurred more frequently in the control cohort (7% vs. 3.8%; p = .03). Incidence of SICU-acquired proven candidiasis significantly decreased from 2.2% to 0% (p < .001). No emergence of azole-resistant Candida species was noted during the prospective period.

Assessment of Preemptive Treatment to prevent severe candidiasis in SICU

Piarroux, et al..Crit Care Med. 2004 Dec;32(12):2443-9.


Slide25 l.jpg

Arch Surgery. 2001;136: 1401-1409


Temporal assessment of candida risk factors in the sicu l.jpg

Temporal Assessment of Candida Risk Factors in the SICU


Pearls of the study l.jpg

Change in Candida risk factors over time is clinically relevant.

Early risk factors at day 1, time of SICU admission.

More than 8 risk factors at any time

Rapid increase in risk factors (clinical deterioration)

APACHE II score > 18 day 3 or 4

Early risk factor maybe evident from day 1 & maybe used with progression of risk factors as fever, duration of antibiotics & mechanical ventilation to assess risk.

? more aggressive surveillance cultures vs. preemptive or empiric therapy.

Pearls of the study


Serological methods early aid in empiric therapy decision making l.jpg

Plasma beta-D-glucan, a cell wall constituent of fungi, was measured before starting antifungal therapy empirically on postoperative patients, colonized with candida & having risk factors for candida infection.

47% of those with positive test responded to Rx but 9% of those negative responded (p<.01) (OR= 13).

Number of sites colonized with candida also predicted response. Colonization at ≥ 3 sites vs. 1 site (p=0.03) (OR=7.57).

In postoperative patients colonized with candida, & with fever despite antibiotics a beta-D-glucan assay was useful for deciding whether to start empiric therapy.

Serological Methods ? early aid in empiric therapy decision making

Takesue Y et al. World J Surg. 2004; 28(6): 625-30.


Research ongoing l.jpg

Randomized Study of Caspofungin Prophylaxis Followed by Pre-Emptive Therapy for Invasive Candidiasis in the ICU.

The study will test the possibility that caspofungin can successfully reduce the rate of candida infections in subjects at risk. It will also test if caspofungin is useful in treating subjects for this disease when diagnosed using a new blood test that is performed twice weekly, permitting earlier diagnosis than current practice standards.

This study is currently recruiting participants. Mycoses Study Group, August 2007

Research Ongoing


Considerations in selection of empiric antifungal therapy l.jpg

High-risk host with hematologic cancer, or stem cell transplantation, severe immunosuppression, hemodynamic instability, gut dysfunction or medication noncompliance use IV agents.   

Prolonged and recent exposure to azoles prior to current episode or significant liver dysfunction or drug-drug interaction avoid azoles.

Pathogen in vitro susceptibility pattern is known for a class of agents, select an agent that is likely to be effective against the specific pathogen.

Site of Infection:

Ocular or central nervous system infection avoid echinocandins. Can use liposomal amphotericin B, fluconazole or voriconazole.

Urinary ex. cystitis select fluconazole or 5-flucytosine.

Considerations in Selection of Empiric Antifungal Therapy


Empiric caspofungin in patients with neutropenia and persistent fever l.jpg

Overall adjusted success rate

Empiric Caspofungin in Patients with Neutropenia and Persistent fever

50

Caspofungin

Liposomal AmB

40

30

33.9%

33.7%

Percent of Patients

*

*

20

14.5%

10

11.5%

2.6%

10.3%

0

Nephrotoxic effect

(p<0.001)

Discontinued the study prematurely (p=0.03)

Caspofungin had significantly fewer : Drug-related clinical or lab adverse events, and

discontinuations due to serious drug-related clinical or lab AEs .

Walsh et al. N Engl J Med. 2004; 351:1391-1402.


Empiric caspofungin vs liposomal amb in persistent fever and neutropenia l.jpg

100

90

80

p=0.044

70

60

50

Percent survival

40

30

20

Caspofungin (n=556)

L-AmB (n=539)

10

0

7

14

42

21

28

35

49

56

63

Study day

Empiric Caspofungin vs. liposomal AmB in persistent Fever and Neutropenia

Superior in preventing overall mortality with less toxicity.

Walsh et al. N Engl J Med. 2004;351:1391-1402


Candidemia in non neutropenic icu patients risk factors for non albicans candida spp l.jpg

Nationwide Australian prospective cohort study.

Patients with ICU-acquired candidemia over 3 yr.

Measured clinical risk factors occurring up to 30 days preceding candidemia.

C albicans 62%, C glabrata 18%, C parasilopsis 8%, C tropicalis 6%, C krusei 4%, Other Candida spp. 2%

Independent risk factors for NCA or potentially fluconazole-resistant species: age (OR 1.3), recent GI surgery (OR 2.9), prior exposure to systemic antifungal agents (OR 4.6) especially fluconazole (OR 5.7).

Candidemia in Non-neutropenic ICU Patients. Risk Factors for Non-albicans Candida Spp.

EG Playford et al. Crit. Care Med. 2008; 36(7): 2034-2039.


Empiric anti candida therapy cost effectiveness l.jpg

Target: Patients in the ICU > 3 days and unresponsive to antibacterial therapy for > 3 days.(~40% all candidemia).

Strategies compared: Fluconazole, Caspofungin, AmB and Liposomal AmB.

Estimates: R to Fluconazole =5%, cost of Caspofungin = 381$/day, Diflucan=135$/d, IC in target population =10%.

Results: Caspofungin the most effective but Fluconazole more cost-effective.

If R to Fluconazole > 28% or if IC prevelance = 60% or if cost of caspofungin <160 $/day then Caspofungin more cost effective.

Empiric Anti-Candida Therapy: Cost-Effectiveness

Golan et al. 2005. Ann Intern Med;143:857-869.


Algorithm for empiric therapy l.jpg

Algorithm for Empiric Therapy

  • Empiric treatment for invasive candidiasis based on the hemodynamic status of the patient.

  • Unstable patients: broad-spectrum antifungal agents, which can be narrowed once the patient has stabilized & the identity of the infecting species is established.

  • In stable patients: fluconazole, provided that the patient is not colonized with fluconazole resistant strains or there has been recent past exposure to an azole (<30 days).

  • In contrast, pre-emptive therapy is based on the presence of surrogate markers ex colonization index.

Spellberg et al. (2006). Clin Infect Dis 42:244–251


Summary empiric therapy l.jpg

In the patient with septic shock risk factors for candidemia should be evaluated.

If Candida infection is suspected, treatment will need to be initiated empirically without delay on the basis of individual patient factors before a definitive diagnosis is made*.

Choice of agent will rely on local resistance patterns, microbiology data, prior azole therapy, recent GI surgery, neutropenia, hemodynamic stability, & other host factors.

Azoles are effective unless high rates of resistance, or neutropenia in which case echinocandins or triazoles should be used.

Summary (Empiric Therapy)

* Surviving Sepsis Campaign: International Guidelines for Management of Severe Sepsis and Septic Shock: CCM 2008


Directed therapy l.jpg

Azoles: Fluconazole is the most common agent used to treat clinical Candida infections. However, fluconazole has limited activity against C glabrata and C krusei. The evolution of resistance and trends toward more non-albicans species, may limit its role in the future.

Triazoles have a role in NCA and immune suppressed patients.

Amphotericin B: active but is not superior to other therapies and therefore does not justify the risk for toxicity. Liposomal AmB is the least toxic.

Echinocandins: shown to be as, if not more, effective than AmB and L-AmB & are not associated with significant resistance. Limited CNS and genitourinary penetration may limit its use.

Directed Therapy


Removal of all foreign objects correlates with better outcomes l.jpg

Removal of all foreign objects correlates with better outcomes*

  • C. albicans biofilms formed on an implanted medical device ex. CVC, urinary catheter, ETT, prosthetic heart valve, or pacemaker play a role in the persistence and profileration of Candidiasis. Cells in biofilms are much more resistant to antifungal agents*.

  • The echinocandins have penetration and action in Candida biofilms and thus may have an advantage in this setting**.

C. albicans adhesion as a virulence factor

* Nucci M et al. 2002. CID; 34: 591-599.

** Kuhn et al. 2002. Antimicrob Agents Chemother; 46:1773-1780.


Summary l.jpg

Candidemia is associated with high morbidity & mortality in ICU.

Early appropriate therapy is essential for the prevention of severe complications, including death.

A combination of clinical & lab findings is used to make a diagnosis (no reliable diagnostic markers for early detection of patients at risk for invasive candidiasis)

Early empiric therapy will need to be initiated on the basis of individual patient risk factors before a definitive diagnosis is made.

Prophylactic & Preemptive therapy maybe indicated in high risk populations at risk for candida infection given the high mortality.

When candidemia is documented, ID of the infecting Candida species is essential for the institution of appropriate therapy because of the variable susceptibility of Candida species to different antifungal agents. Don’t forget to address the biofilm.

Summary


Interactive case questions thank you l.jpg

Interactive Case QuestionsThank you

END


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