The study identified Candida species from clinical samples and tested their sensitivity to antifungal drugs. C. krusei and C. tropicalis were the most common causes of candidemia. Many isolates showed resistance to multiple antifungal drugs. Natural quinonoid compounds were also tested and showed broad antifungal activity comparable to commercial drugs, with plumbagin exhibiting the strongest activity.

1. Antifungal Activity of Quinonoid Natural
Products against Clinical Isolates of Candida spp.
Dr. Diganta Dey
Ashok Laboratory Clinical Testing Centre Pvt. Ltd.
Kolkata

2. Study Protocol
• Species identification of Candida isolates from
different clinical specimens in Vitek2 Compact
using ID-YST cards
• Sensitivity testing against the common
antifungal drugs by disk diffusion method
• Assessment of the activity of quinonoids
natural compounds against these isolates
• Comparison of MIC in broth microdilution:
Quinonoids vs commercial drugs

3. Candida spp. Isolated from different infections
0
1
2
3
4
5
6
7
Blood stream
Urinary
Respiratory
Skin
Vaginal

4. Gram Staining Morphology
C. krusei C. tropicalis C. albicans C. haemulonii
C. lusitaniae C. dubliensis C. pelliculosa C. famata

5. Colonies on Candida Chrome Agar
C. dubliensis
C. tropicalis C. krusei C. haemulonii
C. glabrata
C. albicans
C. parapsilosis

6. Sensitivity to Antifungal Drugs
Sl. No. Candida spp. /Specimen/ lD Sensitive to Resistant to
1 C.krusei/ Blood/ 1364 - AP, KT, VRC, IT, FLC
2 C.krusei/ Blood/ 1969 AP, KT, VRC, IT, FLC -
3 C. tropicalis/ Blood/ 2228 AP KT, VRC, IT, FLC
4 C.krusei/ Blood/ 7975 IT AP, KT, VRC, FLC
5 C. pelliculosa/ Blood/2284 AP, KT, VRC, IT, FLC -
6 C.krusei/ Blood/10085 VRC AP, KT, IT, FLC
7 C.krusei/Blood/28480 AP, KT, VRC, IT FLC
8 C. tropicalis/ Urine/6950 VRC AP, KT, IT, FLC
9 C. haemulonii/ Urine/8027 IT AP, KT, VRC, FLC
10 C. lusitaniae/ Urine/ 6921 AP, KT, VRC, IT, FLC -
11 C. albicans/ Urine/ 48634 AP KT, VRC, IT, FLC
12 C. dubliensis/ Blood/ 2527 AP KT, VRC, IT, FLC
AP: amphotericin B (20 µg), KT: ketoconazole (10µg), VRC: voriconazole
(1µg), IT: itraconazole (10µg), FLC: fluconazole (25µg)

7. Sensitivity to Antifungal Drugs
Sl. No. Candida spp. /Specimen/ lD Sensitive to Resistant to
13 C. famata/ Skin
Scrapping/19070
AP KT, VRC, IT, FLC
14 C. tropicalis/ Blood/ 37509 VRC AP, KT, IT, FLC
15 C. tropicalis/ Blood/ 37279 AP, VRC, IT KT, FLC
16 C.krusei/ Blood/47294 VRC, IT, FLC AP, KT
17 C.krusei/ Vaginal swab/ 47443 AP, KT, VRC, IT, FLC -
18 C. albicans/ Sputum/39314 AP KT, VRC, IT, FLC
19 C. albicans/ Urine/45855 AP KT, VRC, IT, FLC
20 C. Albicans ATCC 60193 AP, KT, VRC, FLC IT
21 C. krusei ATCC 34135 AP, KT, VRC, IT FLC
22 C. glabrata ATCC 90030 AP, KT, VRC, IT, FLC -
23 C. parasilosis ATCC 22019 AP, KT, VRC, FLC IT
AP: amphotericin B (20 µg), KT: ketoconazole (10µg), VRC: voriconazole
(1µg), IT: itraconazole (10µg), FLC: fluconazole (25µg)

8. Quinonoids Studied
Lawsone Menadione Juglone
Emodine Plumbagin

9. MIC (μg/mL) of Quinonoids
Sl. No. Candida spp./ lD LS MD JG ED PG
1 C.krusei/ 1364 256 64 32 256 4
2 C.krusei/ 1969 128 32 2 256 <0.25
3 C. tropicalis/ 2228 256 128 16 256 0.5
4 C.krusei/ 7975 256 128 8 128 2
5 C. pelliculosa/ 2284 128 64 2 128 <0.25
6 C.krusei/ 10085 256 128 32 256 1
7 C.krusei/28480 128 256 8 128 <0.25
8 C. tropicalis/ 6950 256 128 16 256 8
9 C. haemulonii/ 8027 256 256 64 256 16
10 C. lusitaniae/ 6921 256 64 4 128 0.5
11 C. albicans/ 48634 256 128 64 256 4
12 C. dubliensis/ 2527 256 64 8 128 4
LS: Lawson, MD: Menadione, JG: Juglone, ED: Emodine, PG: Plumbagin

10. MIC (μg/mL) of Quinonoids
Sl. No. Candida spp./ lD LS MD JG ED PG
13 C. Famata /19070 128 32 16 256 2
14 C. tropicalis/ 37509 256 128 32 128 4
15 C. tropicalis/ 37279 64 64 2 256 <0.25
16 C.krusei/ 47294 128 64 1 128 <0.25
17 C.krusei/ 47443 128 64 1 128 0.5
18 C. albicans/ 39314 256 128 32 256 16
19 C. albicans/ 45855 256 256 64 256 32
20 C. Albicans ATCC 60193 128 16 0.5 128 <0.25
21 C. krusei ATCC 34135 128 32 1 128 <0.25
22 C. glabrata ATCC 90030 64 32 2 64 0.5
23 C. parasilosis ATCC 22019 64 16 0.5 128 <0.25
LS: Lawson, MD: Menadione, JG: Juglone, ED: Emodine, PG: Plumbagin

11. MIC (μg/mL) of Antifungal Drugs
Sl. No. Candida spp./ lD AP FLC VRC KT CAP
1 C.krusei/ 1364 32 32 64 128 1
2 C.krusei/ 1969 <0.25 0.5 1 <0.25 <0.25
3 C. tropicalis/ 2228 0.5 64 64 128 2
4 C.krusei/ 7975 64 128 256 128 4
5 C. pelliculosa/ 2284 <0.25 8 0.5 4 <0.25
6 C.krusei/ 10085 64 128 1 128 2
7 C.krusei/28480 <0.25 64 <0.25 <0.25 0.5
8 C. tropicalis/ 6950 128 32 1 32 2
9 C. haemulonii/ 8027 128 32 32 16 4
10 C. lusitaniae/ 6921 <0.25 1 2 0.5 <0.25
11 C. albicans/ 48634 0.5 8 16 16 <0.25
12 C. dubliensis/ 2527 0.5 4 32 16 0.5
AP: amphotericin B, FLC: fluconazole, VRC: voriconazole, KT: ketoconazole,
CAP: caspofungin

12. MIC (μg/mL) of Antifungal Drugs
Sl. No. Candida spp./ lD AP FLC VRC KT CAP
13 C. Famata /19070 <0.25 4 8 8 0.5
14 C. tropicalis/ 37509 32 64 0.5 64 32
15 C. tropicalis/ 37279 0.5 32 1 128 <0.25
16 C.krusei/ 47294 2 32 34 1 1
17 C.krusei/ 47443 <0.25 0.5 1 2 <0.25
18 C. albicans/ 39314 1 64 32 128 16
19 C. albicans/ 45855 2 128 256 64 4
20 C. Albicans ATCC 60193 0.5 1 <0.25 2 <0.25
21 C. krusei ATCC 34135 <0.25 16 1 0.5 0.5
22 C. glabrata ATCC 90030 <0.25 0.5 0.5 1 <0.25
23 C. parasilosis ATCC 22019 0.5 1 <0.25 2 <0.25
AP: amphotericin B, FLC: fluconazole, VRC: voriconazole, KT: ketoconazole,
CAP: caspofungin

13. Conclusions
• In current study, 55% of candidemia was
found to be associated with C. krusei, and 27%
was caused by C. tropicalis
• Most of such infections (55%) were observed
in newborns (Data not shown)
• Out of 19, 9 isolates (47%) were resistant to
any 4 tested drugs, while 2 isolates (10.5%)
were found to be resistant to all 5 tested
antifungal agents

14. Conclusions
• All the tested quinones exhibited broad
spectrum antibacterial activity (lowest MIC
<0.25 μg/mL)
• The antifungal activity of these compounds
were more or less comparable with the
commercial drugs
• The order of antifungal activity of the tested
quinonoids was Plumbagin > Juglone >
Menadione > Lawsone > Emodine