Recent advances in Candida

1
Recent advances in Candida candidiasis The
changing face of antifungal drug resistance

• Sevtap Arikan, MD
• Hacettepe University Faculty of Medicine
• Ankara Turkey

2
Novel concepts

• New antifungal drugs were developed
• Species distribution of Candida changed (at least
  in some centers)
• Non-albicans Candida are more commonly
  encountered than before (at least in some
  centers)
• Among these species, some are less susceptible or
  primarily resistant to antifungal drugs
• Secondary resistance is now observed even in
  strains of very susceptible species

3
More antifungal drugs..
4
Changing face of antifungal drug spectrum
1960s Amphotericin B Miconazole
Clotrimazole Flucytosine
1980s Ketoconazole (po)
1950s Griseofulvin First azole
1970s Econazole Miconazole (IV)
Micafungin Anidulafungin Posaconazole Ravuconazol
e Sordarins...
1990s Fluconazole Itraconazole Terbinafine Lipid
Ampho formulations
2000s Caspofungin Voriconazole
5
Antifungal drugs--by structure

• POLYENES
• Amphotericin B, nystatin
• AZOLES
• Imidazoles Ketoconazole..
• Triazoles Fluconazole, itraconazole,
  voriconazole, posaconazole, ravuconazole
• ALLYLAMINES
• Terbinafine, butenafine
• MORPHOLINE
• Amorolfine
• FLUORINATED PYRIMIDINE
• Flucytosine

• ECHINOCANDINS
• Caspofungin, anidulafungin, micafungin
• PEPTIDE-NUCLEOSIDE
• Nikkomycin Z
• TETRAHYDROFURAN DERIVATIVES
• Sordarins, azasordarins
• OTHER
• Griseofulvin

6
Antifungal drugs--by mode of action

• Membrane disrupting agents
• Amphotericin B, nystatin
• Ergosterol synthesis inhibitors
• Azoles, allylamines, morpholine
• Nucleic acid inhibitor
• Flucytosine
• Anti-mitotic (spindle disruption)
• Griseofulvin

• Glucan synthesis
• inhibitors
• Echinocandins
• Chitin synthesis
• inhibitor
• Nikkomycin
• Protein synthesis inhibitors
• Sordarins, azasordarins

7
Most commonly used drugs to treat candidiasis

• Amphotericin B and its lipid formulations
• Fluconazole
• Itraconazole
• Ketoconazole, topical azoles, nystatin
• Caspofungin (including flu-resistant refractory
  cases and invasive infections)
• Voriconazole (indicated in Europe/UK in treatment
  of serious invasive Candida infections also
  effective in esophagial candidiasis

And now also
Arikan Rex. Manual of Clinical Microbiology
2003, 8th ed., 1859 Arikan Rex. Expert Opin
Emerging Drugs 2002 7 3 Arathoon et al. AAC
2002 46 451, Mora-Duarte et al. NEJM 2002 347
2020
8
Species Any change?Any increase in non-albicans
Candida?
9
Identify the SPECIES of your Candida
VIRULENCE
ANTIFUNGAL DRUG SUSCEPTIBILITY
and
variable
Treatment modalities and attributable mortality
may vary from one species to other
10
Specific risk factors for infections due to
non-albicans Candida

• Hematological malignancy
• Neutropenia (C. krusei, C. tropicalis)
• Antifungal prophylaxis (C. krusei, C. glabrata)
• Prior use of fluconazole (C. krusei, C. glabrata)
• Colonization at two sites
• Existence of catheter (C. parapsilosis, C.
  glabrata)
• Surgery (C. glabrata)
• Hospitalization at surgical intensive therapy
  unit
• Renal failure
• Raised APACHE II score
• Previous polyene use (C. lusitaniae, C.
  guilliermondii)
• Burns (C. rugosa)

Krcymery Barnes. J Hosp Infect 2002 50 243
Abi Said Anaissie. Baillieres CID 1998 7
1131 Abi Said et al. CID 1997 24 1122
Bloomberg et al. CID 1998 27 939 Krcmery V Jr
Acta Chemoth 1999 5 133 Pic Alaus et al. CID
1998 27 981 Viscoli et al. CID 1999 28 1071
Wingard JR. CID 1995 20 115
11
Non-albicans candidemia () in adult cancer
patients
High variations
Viscoli et al. CID 1999 28 1071, Krcmery V Jr.
Acta Chemother 1999 5 133 Rex et al. AAC 1995
39 40 Noskin et al. CID 1996 23 874 Wingard
JR. CID 1995 20 115 Abi Said et al. CID 1997
24 1122 Lecciones et al. CID 1992 14 875
12
Non-albicans candidemia () in adult non-cancer
patients
again variable
Hospitalization at intensive care unit and/or
surgery
Eubanks et al. Am J Surg 1998 166 617 Fraser
et al. CID 1992 15 414, Nguyen et al. Arch Int
Med 1995 155 2429 Voss et al. Infection 1997
25 8, Abele-Horn et al. Infection 1996 24 426
Pappas et al. CID 1997 25 357 Bloomberg et al.
CID 1998 27 939 Papafrangis et al. CID 1998
27 980 Krcmery Barnes. J Hosp Infect 2002
50 243
13
Longitudinal studies A ten-year fungemia survey

• Possible reasons for this increase
• More transplantation
• Increase in use of intravascular devices
• Increase in use of antifungal agents

Krcmery V Jr. et al. DMID 2000 36 7. Slovak
Republic
14
A five-year fungemia survey
Baddley et al. DMID 2001 39 199. UK
15
But.. Not a significant increase of non-albicans
Candida in other centers..
Isolates from blood and sterile body sites
Samra et al. EJCMID 2002 21 542. Israel
16
albicans vs. non-albicansHacettepe University,
Ankara Turkey1996-2002
17
albicans vs. non-albicans
Isolates from all patients, all clinical samples
18
Bloodstream isolates
Trichosporon (n5) Rhodotorula (n2) Fusarium
(n1)
19
Candida krusei vs. other species
Isolates from all patients, all clinical samples
20
Bloodstream Candida krusei isolates
21
So..

• A shift from albicans to non-albicans Candida
• is observed in some centers
• Inter-institutional variations are common
• The underlying mechanism is not fully clarified
• Selective pressure of azoles is probably
  significant
• Central venous catheters, nosocomial transmission
  transmission between partners may also play role

Baran et al. Scan J Infect Dis 2001 33 137
Dromer et al. AIDS 1997 11 1095 Price et al.
AAC 1994 38 1422 Wingard et al. NEJM 1991
325 1274 Merz et al. JCM 1986 24 581
22
Isolation frequency of each Candida species

• C. albicans is still the leading one
• The rank order of other species may vary
  according to the anatomical site of isolation,
  geographical location other underlying factors
• In general, C. glabrata is usually the second
  most common in USA whereas it is tropicalis in
  several other locations
• C. parapsilosis usually predominates among
  bloodstream and intravascular catheter isolates

23
Species vs. susceptibility profile
NCCLS M27-A2
NCCLS M44-P
24
MIC breakpoints Established for only some drugs
Ampho MICs are distributed in a narrow range,
incapacitating the discrimination of resistant
isolates. Antibiotic Medium 3 may help
(contraversial data) Nguyen et al. J Infect Dis
1998 177 425 Rex et al. AAC 1995 39 906
NCCLS M27-A2, 2002, reference microdilution
method
25
In vitro and/or in vivo resistance has been
reported for..
Itraconazole
Fluconazole
dubliniensis norvegensis inconspicua tropicalis al
bicans
A subset of flu-resistant isolates
secondary rarely
krusei glabrata
intrinsically resistant to fluconazole
relatively high MICs / clinical failure
Ampho B
lusitaniae guilliermondii rugosa
Arikan et al. JCM 2002 40 1406 Martinez et al.
JCM 2002 40 3135 Yoon et al. AAC 1999 43
836 Baily et al. CID 1997 25 161 Moran et al.
AAC 1997 41 617 Sandven et al. AAC 1997 41
1375 Stevens et al. DMID 1996 26 145 Morgan
et al. AAC 1998 42 1819 Merz WG. JCM 1984 20
1194 Favel et al. JAC 1999 43 227
26
Triazoles
27
Extent variability of resistance () to
fluconazole at different centers
Europe, multicenter International
Kuwait Romania Singapore Turkey UK USA
Prodhom et al. Clin Microbiol Infect 2003 9
P713 Chugh et al. Clin Microbiol Infect 2003 9
P1501 Pfaller et al. JCM 2003 41 1440 Alecu
et al. Clin Microbiol Infect 2003 9 P558
Yang et al. JCM 2003 41 472 Arikan et al. 4th
ECC 2002 PM144 Baddley et al. DMID 2001 39
199 Baran et al. JCM 2000 38 870
28
Extent variability of resistance () to
itraconazole at different centers
Europe, multicenter International
Kuwait Turkey UK USA
Prodhom et al. Clin Microbiol Infect 2003 9
P713 Chugh et al. Clin Microbiol Infect 2003 9
P1501 Pfaller et al. JCM 2003 41 1440 Arikan
et al. 4th ECC 2002 PM144 Baddley et al. DMID
2001 39 199
29
Extent of azole cross-resistance
Flu-S (n 3479)
Flu-S-DD (n323)
Flu-R (n157)
Pfaller et al. AAC 2003 47 1068
30
C. albicans Phenotype- serotype- dependent
azole susceptibility variations

• Stippled phenotype
• Serotype B

higher fluconazole and itraconazole MICs
Velegraki et al. EJCMID 1996 15 854 Velegraki
A. J Med Vet Mycol 1995 33 83
31
Voriconazole
Candida krusei Untreated control /treated with
fluconazole Transmission electron micrograph
Candida krusei Treated with voriconazole
Belanger et al. AAC 1997 41 1840
www.doctorfungus.org
32
In vitro activity
MIC90

• NCCLS, M27-A2
• C. albicans 0.015-0.5
• C. parapsilosis 0.015-0.125
• C. kefyr 0.015
• C. tropicalis 0.03-16
• C. glabrata 0.25-4
• C. krusei 0.25-2
• C. lusitaniae 0.5

Very active against Candida Vori MICs usually
follow flu and itra MICs and tend to be higher
for isolates with high flu MICs
MIC breakpoint is yet unestablished (1 µg/ml
??)
Matar et al. AAC 2003 47 1647 Chryssanthou et
al. JCM 2002 40 3841 Laverdiere et al. JAC
2002 50 119 Pelletier et al. J Med Microbiol
2002 51 479 Pfaller et al. DMID 1999 35 19
Uzun et al. DMID 2000 38 101
33
Mechanisms of azole resistance
Resistance may be azole-specific, depending on
the specificity of the resistance mechanism.
Azole cross-resistance is observed in a subset
of isolates.Pfaller et al. AAC 2003 47 1068
Stevens et al. DMID 1996 26 145

Canuto MM Rodero FG. The Lancet Infect Dis
2002 2 550
34
Polyenes
35
Extent of amphotericin B resistance

• Hard to evaluate due to technical problems of
  susceptibility testing
• Estimated to be
• 5-20 of C. lusitaniae
• 5-20 of C. rugosa
• 10-15 of C. krusei
• 5-10 of C. guilliermondii

Krcymery Barnes. J Hosp Infect 2002 50 243
36
Lipid amphotericin B formulations comparative in
vitro activity

• Candida spp.
• AMB L-AMB
• Anaissie et al. Eur J Clin Microb Infect Dis
  1991 10 665
• AMB gt L-AMB
• Pahls et al. J Infect Dis 1994 169 1057
• In vitro activity may somewhat differ.
  Amphotericin B is the sole component that
  provides antifungal activity in all formulations.
  Thus, testing the lipid formulations in vitro may
  not be required.
• The major concern is the enhanced in vivo
  activity of lipid formulations.

37
Why are they occasionally more efficacious in
VIVO ??

• Exact mechanism unknown
• ? Selective uptake into RES
• ? Higher uptake, retension, and slow release by
  macrophages

Macrophage
Liposome
Lysosome
Fusion
Liposome degradation
Endocytosis
Storm et al. Eur J Clin Microbiol Infect Dis
1997 1664 Wasan et al. Eur J Clin Microbiol
Infect Dis 1997 16 81 Mehta et al. J Infect Dis
1997 175 214
Endocytic vesicle
Release from macrophage
Release in blood compartment
38
Mechanisms of amphotericin B resistance

• Reduced ergosterol content (defective ERG2 or
  ERG3 genes)
• Alterations in sterol content (fecosterol,
  episterol reduced affinity)
• Alterations in sterol to phospholipid ratio
• Reorientation or masking of ergosterol
• Stationary growth phase
• Previous exposure to azoles
• Production of melanin

Ghannoum et al. Clin Microbiol Rev 1999 12 501
39
Echinocandins
40
Caspofungin
Canuto MM Rodero FG. The Lancet Infect Dis
2002 2 550
41
In vitro activity
MIC90

• C. albicans 0.25-2
• C. glabrata 0.25-2
• C. tropicalis 0.5-1
• C. parapsilosis 2-4
• C. kefyr 0.5-2
• C. krusei 1-2
• C. guilliermondii 2-gt16
• C. lusitaniae 0.5-2
• C. famata 4

Recommended dosing provides peak plasma
concentrations in excess of 8 µg/ml
Fungicidal against some isolates (C. albicans,
C. glabrata, C. tropicalis)
Is effective against C. albicans C.
parapsilosis biofilms
Pfaller et al. AAC 2003 47 1068 Arikan et al.
4th ECC 2002 PM144 Roling et al. DMID 2002 43
13 Kuhn et al. AAC 2002 46 1773 Ernst et al.
DMID 1999 33 75 Klepser et al. AAC 1998 42
1387 Espinel-Ingroff. JCM 1998 36 2950
Krishnarao et al. AAC 1997 41 1957
42
In vitro-in vivo correlation

• Invasive candidiasis (n224)
• C. parapsilosis (n8)
• C. guilliermondii (n3)
• C. albicans (n1)
• C. rugosa (n1)
• C. tropicalis (n1)

Caspofungin MIC gt 4 µg/ml Clinical
response ()
? MIC breakpoint is not yet established
Bartizal et al. 42nd ICAAC 2002 M-1240
43
Caspofungin is active against both flu-S ve flu-R
Candida
Cas (µg/ml)
Flu (µg/ml)
n239
Arikan et al. 4th ECC 2002 PM144
44
..and Itra-S ve Itra-R Candida
Cas (µg/ml)
Itra (µg/ml)
n239
Arikan et al. 4th ECC 2002 PM144
45
Fluorinated pyrimidine
46
Flucytosine

• Not very commonly used for treatment of
  candidiasis
• Monotherapy should be avoided to prevent
  development of resistance
• C. albicans resistance
• lt 8 (North America)
• 0-0.2 (Europe)

St Germain et al. JCM 2001 39 949
Cuenca-Estrella et al. EJCMID 2001 20 276
Barchiesi et al. JAC 2000 45 408 Hoban et al.
AAC 1999 43 1463 Kao et al. CID 1999 29
1164 Pfaller et al. DMID 1998 31 327
47
Antifungal agents comparative activity
48
Extent of activity of common systemic antifungal
agents--in general
reliable activity with occasional
resistance moderate activity but resistance
is noted occasional activity 0 no
meaningful activity
Arikan Rex. Manual of Clinical Microbiology
2003, 8th ed., 1859
49
Correlation of in vitro susceptibility with
clinical outcome
50
Resistance may be..
IN VITRO
IN VIVO
CLINICAL FAILURE
51
A meta-analysis..
Clinical success
Candida -fluconazole Candida - itraconazole Candid
a - ketoconazole C. neoformans -
fluconazole Histoplasma - fluconazole
Rex et al. CID 2002 35 982
52
..and lastly
53
Optimizing antifungal therapy by species
identification and/or susceptibility testing

• Periodically assess the susceptibility patterns
  in your center
• If the incidence of non-albicans Candida is gt50
  in your center, prefer amphotericin B (rather
  than fluconazole) for empirical treatment
• Prefer amphotericin B if fungemia is due to
  C.krusei
• Prefer fluconazole if fungemia is due to
  C.lusitaniae
• Use amphotericin B or fluconazole for C.glabrata
  and C.tropicalis until susceptibility testing
  results are available

Krcmery Barnes. J Hosp Infect 2002 50 243
54
Prevention of development of resistance

• Is not fully possible!-- Fungi are very smart! ?
• Try to restrict and well-define the indications
  for treatment and prophylaxis
• More importantly, try to prevent the infection
• ? Immune status of the host
• ? Intravascular devices
• ? Control measures to reduce nosocomial
  transmission