0:05

Hi, everyone. Welcome to

0:07

Febrile, a culture podcast about all things

0:09

infectious disease. We use

0:11

console questions that dive into ID

0:13

clinical reasoning, diagnostics, and antimicrobial

0:15

management. I'm Sarah Dong, your

0:18

host at a MedPeds ID doc. Today's

0:21

episode of Below the Belt is led

0:23

by a team from Australia. First

0:26

up, we have Dr. Morgan Hui. Morgan

0:28

is a basic physician's trainee with

0:30

an interest in infectious diseases. He

0:33

is currently working as an ID

0:35

registrar at Peninsula Health in Melbourne,

0:37

Australia. Hi, it's Morgan, very keen

0:39

to be here today. Dr.

0:42

Jonathan Darby is an infectious diseases

0:44

and general medicine physician. He

0:46

is the head of general medicine

0:48

at St. Vincent's Hospital in Melbourne and

0:51

an associate professor at the University of

0:53

Melbourne. Hi, it's great to

0:55

be here with you today. Dr. Max

0:57

Olensky is an infectious diseases and

0:59

general medicine physician with an interest

1:01

in tropical medicine and infections in

1:03

immunocompromised host. He is the

1:05

current perioperative medicine unit clinical

1:07

lead at Peninsula Health and

1:09

a sectional academic with Monash University

1:11

in Melbourne. Hi, it's

1:13

Max Olensky here. Thanks so much for having us today.

1:15

Really excited for this podcast. Dr.

1:18

Katrina Halliday is the principal hospital

1:20

scientist in charge of the

1:22

Clinical Mycology Reference Lab at the

1:24

University for Clinical Pathology and

1:26

Medical Research and New South Wales

1:28

Health Pathology based at Westmead

1:30

Hospital in Sydney. She is actively

1:32

involved in teaching both scientific

1:34

and medical staff in medical mycology

1:36

and has a strong interest

1:38

in culture independent tests to aid

1:40

in the rapid diagnosis of

1:43

invasive fungal infections and anti -fungal

1:45

drug susceptibility surveillance. Hi,

1:47

it's Katrina Halliday and nice to be

1:49

here too. Wonderful. Thank

1:51

you guys so much for coming. We

1:53

are just going to quickly start by asking

1:55

you to share a little piece of

1:57

culture because we call February everyone's favorite

1:59

cultured podcast. It's really just sharing

2:01

a little something non -medical that you

2:03

like, whether that's pop culture or

2:05

hobbies or other interests that you

2:07

have. So what have you guys

2:09

been enjoying recently? I

2:12

had the pleasure of going to

2:14

see recently for International Women's Day.

2:16

I went to see the RBG

2:18

of many one production about Ruth

2:20

Bader Ginsburg's life, which was fantastic.

2:22

It's one woman show. I think

2:24

it's two of the states and

2:26

it's come back time and time

2:28

again in Australia. Of course, I

2:30

haven't seen it. I was going

2:32

to say that in recent times,

2:34

my daily routine is incorporated the

2:36

New York Times puzzles. I sort

2:38

of churned through them every morning.

2:40

while I'm having my morning coffee.

2:43

And also I've been doing their Crypto Crossword

2:45

of Light to try and get my

2:47

creative juices flowing. Excellent. Love a good puzzle.

2:50

Hi, Morgan. Since COVID,

2:52

I think I've been picking up

2:54

golf after lockdown. Not

2:56

that I play well, but

2:58

it's enjoyable to get outdoors.

3:01

And then in the same vein, I've

3:03

been watching a lot of golf YouTube,

3:05

especially between studying. It's very easy

3:08

watching. And it's just something to

3:10

turn my brain off. And I, which is

3:12

quite good. Yeah. The

3:14

turning your brain off is

3:16

usually a common theme on people's

3:19

suggestions and rounding yourself Jonathan.

3:21

Well, I saw you like travel

3:23

and food. So yesterday, at

3:25

weekend, Australian time, I

3:27

said to my kids, going to cook dinner

3:29

and they requested bao buns. So I made

3:31

bao buns yesterday, which was good fun. Labor

3:33

of love takes most of the day. A

3:35

lot of work. It was very nice. Yeah.

3:38

Very nice. Amazing. I love

3:40

it. Well, thank you guys for

3:42

sharing. All right. Well, Morgan

3:44

is in charge today and is going to take

3:46

us to the case. So I'll hand it

3:48

over. Thank you. So

3:51

today, our case involves a 49 -year

3:53

-old male who presents to the

3:55

renal outpatient department with a form

3:57

of history of a slow -growing painless

3:59

right elbow lesion. He's

4:01

adherent with his immunosuppression and

4:03

a systems review is unrevealed. His

4:06

past medical history includes

4:08

a renal transplant in 2017,

4:10

for primary focal -segmental glomerular

4:12

sclerosis. His pre

4:14

-transplant assessment did not reveal any

4:17

infections for which prophylaxis was

4:19

afforded. His

4:21

early post -transplant course was

4:23

complicated by pulmonary espigelosis, and

4:26

he was treated with a

4:28

six -month course of voriconazole with

4:30

clinical, biochemical, and radiological resolution. At

4:33

the time of seeing him,

4:35

he has a stable allograft function

4:37

currently on low -dose predesalone. Evrolimus

4:39

and Tochrolimus, and his

4:41

co -orbidities include well -controlled hypertension, dyslipidemia,

4:44

steroid induced osteoporosis, and

4:46

gourd. On

4:49

examination, his vitals were normal

4:51

alongside a normal cardiac respiratory exam. His

4:54

abdominal examination revealed a

4:56

non -tender, right -level quadrant mass

4:58

underlying a hockey stick

5:00

scar consistent with a renal

5:02

allegra. Here's a

5:04

1 .5 centimeter non -tender and

5:06

mobile lump on the lateral

5:08

aspect of his right elbow, not

5:11

to the to the underlying skin, without

5:14

notable discolouration, overlying

5:16

skin changes, ingeration,

5:18

no sinus. There

5:20

were no other masses on examination

5:22

of his lympho stations. At

5:25

this point, is there anything else that

5:27

you'd want to ask our patients and what

5:29

differentials do you think that you'd entertain? Thanks

5:32

Morgan, so just to summarise,

5:34

this is a Middle -A's gentleman.

5:36

who's a renal allograft recipient with

5:38

stable function on immunosuppression. His

5:41

post -transplant course was complicated in

5:43

the early stages with pulmonary aspergillosis,

5:45

but he seems to have recovered

5:47

from that with therapy and presents

5:49

now with an incidental painless lump

5:51

on his elbow. Some

5:53

important questions that come to mind

5:55

really are clarification surrounding exposures. For

5:57

instance, what he does for work, what sort

5:59

of hobbies he has, has

6:01

he had any animal contact or

6:03

a little bit more about his sexual

6:05

history. What else is

6:08

important would be whether there are

6:10

other local regional infections or constitutional

6:12

symptoms of note. The

6:14

differential diagnosis for a painless lump in a

6:16

transplant recipient runs the gamut from a

6:18

foreign body reaction to things like a lipoma

6:20

or other soft tissue neoplasms. And

6:22

this includes lymphoma. But considering

6:24

this is through the lens of an

6:26

infection disease approach, I think it's important

6:28

to entertain various sorts of infections and

6:30

likewise we'd entertain things like run -of -the

6:33

-mill bacterial, skin -soft tissue infections like a

6:35

furuncle or a carbuncle, but

6:37

syphilis and cat scratch disease also appear amongst

6:39

the differentials. Considering a significant

6:41

history, fungal ethyl need to

6:43

be entertained, and this includes

6:45

disseminated aspergillosis alongside spore trichosis

6:47

and more rare things like

6:49

mupormycosis or rosopus infection. And

6:52

then the fine print would be things like macrobacterial

6:54

infection, viral or parasitic infections,

6:56

things like TB or non -tibiculus

6:58

macrobacteria. or cysticostasis,

7:00

but those sort of things really

7:03

come to the fore if his

7:05

exposure history was compatible. Taking our

7:07

case a bit further, his social

7:09

history revealed that the patient emigrated

7:11

from the Philippines to Australia 18

7:13

years previously, where he returns to

7:15

visit family and friends every six

7:17

to 12 months, but not at

7:19

recent times. He's a

7:21

long -term heterosexual, monogamous relationship and

7:23

works in maintenance at an

7:25

aged care facility. He's

7:27

a sporadic gardener. with no

7:29

additional epidemiological exposures and

7:31

does not report any recent

7:33

animal nor insect contact

7:35

nor recent local regional infection.

7:38

He consumes no alcohol nor

7:40

smokes tobacco. On

7:43

further history, when pressed, he thinks

7:45

that he might have had the

7:47

onset following a seamlessly innocuous traumatic

7:49

injury against a doorknob without

7:51

skin breach and no set associated

7:53

systemic upset. His

7:55

routine lab results were unremarkable.

7:58

with white cell count, LFTs and

8:00

inflammatory markers within normal limit,

8:02

a stable renal function compared to

8:04

previous, a non -reactive

8:06

RPR and a negative quantifier

8:08

on gold with a good nitrogen

8:10

response. Ultrasonicrophy

8:12

of the lesion revealed

8:14

two small circumscribed ovoid

8:17

masses suggestive of reactive

8:19

lefatinography. This was

8:21

clinically corroborated on surgical

8:23

review and was resected on

8:25

block. with tissue set

8:27

up for histopathological assessment alongside

8:29

routine mycobacterial and fungal

8:31

cultures. No organisms

8:33

were seen from the gram

8:36

and zeal nilson stains nor

8:38

subsequently cultured, however filamentous fungi

8:40

were noted on fluorescent staining.

8:44

Histopathological examination revealed multi

8:46

-nucleated giant cells and

8:48

possible copper penny

8:50

aka medlar bodies. In

8:53

addition, there was a

8:55

suggestion of a brown microcolony

8:57

of hyphel element was suspicion

8:59

for an underlying deep mycosis

9:01

and the specimen was sent

9:03

for further culture and identification. I

9:07

guess now, what do you

9:09

think is meant by deep mycosis

9:11

and how they differentiate? Yeah,

9:13

thanks for that update Morgan on the case.

9:16

To just take a step back,

9:18

this was a subcutaneous leak

9:20

and it didn't have any changes

9:22

on the skin which would

9:25

make us think of an inoculation

9:27

injury but we were certainly

9:29

taken by the history of his

9:31

previous aspergillus infection in the

9:33

lung and wondered if this was

9:35

a site of disseminated infection

9:37

and there is as you've pointed

9:39

out max of broad differential

9:41

in a immunosuppressed transplant patient with

9:43

any lesion. But it was

9:46

an unusual site, it was an

9:48

unusual appearance with relatively few

9:50

other additional symptoms just that it

9:52

brought this mass -like lesion to

9:54

our attention. And

9:56

so to be honest, I hadn't

9:58

really used the term deep mycosis

10:00

in clinical practice before. I

10:03

know it's being raised here and

10:05

has been talked about in some literature,

10:07

but really when we think about

10:09

these lesions, we have a broad differential

10:11

from bungalow to atypical mycobacteria to

10:13

other organisms, which may be indolent and

10:15

slow growing in a transplant patient. But

10:17

this suggestion here with the

10:19

the pigmented nature of the

10:21

fungal element certainly makes us

10:23

concerned about a group of

10:25

fungi which we classify in

10:27

the dematiaceous mold group. This

10:31

is an unusual finding so this

10:33

doesn't happen every day where you

10:35

find this on a biopsy and

10:37

sometimes has been found in further

10:39

other organ sites such as brain

10:41

or life or some itaneous skin

10:43

and soft tissue. So the overarching

10:45

term we would sort of use

10:47

for this would be a pheo

10:50

-mycosis if it is related to

10:52

a pigmented mole. I actually had

10:54

to look up the word pheo

10:56

because I've always wondered where that

10:58

came from. And that's a Greek

11:00

word for dusky. So gray

11:02

or black forming. And

11:04

this is thought to be

11:06

the melanin in this group

11:08

of fungal infections structure that

11:10

causes that appearance. So

11:12

there's a few terms we use

11:15

here. And then the other term

11:17

that we would consider is this

11:19

term of chromoblastomycosis where a chronic

11:21

infection usually due to inoculation but

11:23

it could be dissemination in an

11:25

appropriate host such as this with

11:27

dissemination. There is

11:29

a well -known entity in the

11:31

tropics where these patients have

11:34

a crusted varucous -like lesion

11:36

on the skin with chromoblastomycosis

11:38

and there's a range of

11:40

specific species which are fairly

11:42

geographically distinct depending on where.

11:44

patient may have spent time. And

11:47

so with this individual whilst

11:49

living in residential suburb of Australia,

11:51

we did note that his history is

11:53

from the Philippines and travelling back

11:55

and forth there fairly frequently with some

11:58

sparse gardening. So

12:00

we were concerned about this

12:02

family of organisms from

12:04

that basic microbiological description before

12:06

we had a formal

12:08

culture and identification from our

12:10

Micology Reference Laboratory. The

12:12

next step in his workup

12:14

was the sterile tissue was sent

12:16

to a diagnostic mycology laboratory

12:18

for specialized fungal cultures. From

12:21

here, Catriona will take us through

12:23

exactly what happens in the lab to

12:25

get our diagnosis. Thanks

12:27

very much, Morgan. And

12:30

thank you, John, for that nice history.

12:32

And my, I've now learnt what fire means

12:34

in the fire hypomycosis. I've got a case

12:36

at the moment, so that's good. Okay,

12:38

so when the sample was

12:41

sent to us for culture,

12:43

we already knew that there

12:45

were fungal elements seen histologically.

12:47

When we receive samples in the

12:50

fungal lab, it's really important

12:52

that any tissue samples aren't actually

12:54

ground up. We just make

12:56

them into small pieces and put

12:58

them onto the various agar

13:00

and we don't grind them up

13:02

because if this fungus was

13:04

likely to be, or sometimes we

13:06

don't even know it will

13:08

be, a mucamycete. This particular group

13:10

of fungi are really, really

13:12

fragile and grinding would destroy the

13:15

hyphae and so the organism

13:17

would be non -viable. So

13:19

as a rule, no tissue samples

13:21

are ground up in a mycology laboratory.

13:24

So these sterile pieces of

13:26

tissue were put onto a

13:28

variety of different media. We

13:30

usually use a couple of

13:32

different media. a very general

13:34

purpose media with no antibiotics

13:36

such as sabros dextrose agar

13:38

and then we use more

13:40

nutritious media such as a

13:42

sabros dextrose agar base which

13:44

might have something like brain

13:46

heart infusion and some antibiotics

13:49

like chloramphenicol and gentamicin in

13:51

them to suppress any bacterial

13:53

growth. So following inoculation

13:55

we then use plates but some

13:57

labs do use slopes. the plates

13:59

we seal them with parafilm and

14:01

then we put them in an

14:03

incubator at 30 degrees rather than

14:05

35 degrees which is what would

14:07

be used for most of the

14:09

bacterial growth. And 30 degrees

14:11

I think most fungi are environmental

14:13

organisms and they just do better

14:15

for growing at a slightly lower

14:17

temperature. We keep these

14:19

plates for four weeks and look at

14:21

them every couple of days and

14:23

so the reason that parafilmed is is

14:25

both to keep the

14:28

lids closed, but also prevent

14:30

dehydration when they're put in the

14:32

incubators for quite a long

14:34

time. So that's the reason

14:36

we use that lower temperature. And

14:38

in this particular case, after about

14:40

10 days, we noticed a small

14:42

amount of growth of a dark

14:45

grey fungus growing directly out of

14:47

that tissue. So

14:49

as soon as we get positive

14:51

culture, we would then always

14:53

work in a biological safety cabinet.

14:55

We would then put that

14:58

organism and subculture it onto a

15:00

general purpose saberous agar with

15:02

no antibiotics in it. And we'll

15:04

also prepare a slide culture

15:06

by inoculating a potato dextrose agar

15:09

plate. In order to

15:11

identify fungi in the conventional way,

15:13

you really need to see

15:15

how those fungi are growing in

15:17

their natural state. And so

15:19

for that, you can use macroscopic

15:21

appearance, but the macroscopic appearance

15:23

can change depending on the media

15:25

that you might be using,

15:27

how much light there might be

15:29

exposed to and things like

15:31

that. The macroscopic appearance can be

15:33

a bit of a guide,

15:36

but that microscopic appearance is what

15:38

we need to identify something

15:40

to the genus and ideally the

15:42

species level. So

15:44

you need to use a media

15:46

such as potato, dextrose, agar to

15:48

encourage that sporulation. other

15:50

media that could be used for

15:52

microscopy to prepare slide cultures is

15:54

cornmeal agar, which is probably a

15:56

little bit less nutritious and more

15:59

encouraging of sporulation. So

16:01

in this particular case,

16:03

again, we grew a very

16:05

gray, velvety fungus with

16:07

radial grooves. It changed and

16:09

became a bit darker

16:11

with age on the sabros

16:13

plate, and there was

16:15

a bit of a dark

16:17

exudate or droplets forming

16:19

directly out of that colony.

16:22

The reverse of the colony was also

16:24

dark, so the fact that it

16:26

was dark on the reverse as well

16:29

as on the surface suggests that

16:31

the organism does contain melanin, which fits

16:33

with what was seen histologically. Unfortunately,

16:36

the microscopic appearance of this

16:38

fungus from the slide culture was

16:40

not very helpful. We just

16:42

got hyphaed. We didn't see any

16:44

canidia forming. And so if

16:46

you don't see Canadian warming out

16:48

of that high, we can't

16:50

identify it using conventional methods. Fortunately,

16:53

we have the ability

16:55

to overcome this problem and

16:57

perform DNA sequencing, which

16:59

is actually now considered the

17:01

gold standard for identification of

17:03

fungi. There's a

17:06

couple of different barcoding genes

17:08

for fungo identification that

17:10

we rely upon, the

17:12

internal transcribe spacer region, as

17:14

well as some organisms

17:16

that might identify better with

17:18

something like the elongation

17:21

factor gene. But for this

17:23

particular case, we used

17:25

DNA sequencing of the internal

17:27

transcribe spacer region, as

17:29

well as the D1, D2

17:31

region of the 28s

17:34

ribosomal DNA. We did

17:36

two different PCRs. We

17:38

sent that PCR product off

17:40

for sequencing and ran

17:42

the sequence results against GenBank

17:44

data. databases using a

17:46

blast -in algorithm. And

17:49

I'd never had encountered

17:51

the answer that we got,

17:53

but the answer we

17:55

did get from both the

17:57

ITS sequencing was 99 .4

17:59

% identity to an organism

18:01

called bouncy formasphora lignitalis.

18:03

And I might have butchered

18:05

that pronunciation, but I'm

18:07

happy for someone else to

18:09

correct it. And

18:11

then the next closest match

18:13

was another species within that

18:15

farsie formospora species, but it

18:18

was further away at only

18:20

96 % identity. So we were

18:22

pretty confident that the organism

18:24

we'd come across was this

18:26

lignitalis. We

18:29

did try and do antifungal

18:31

susceptibility testing for this patient,

18:33

but again, with antifungal susceptibility

18:36

testing, you must have

18:38

sporulation and we didn't managed

18:40

to induce sporrelation and therefore

18:42

we weren't able to perform

18:44

antifungal susceptibility testing in this

18:46

particular case. Was it

18:48

far enough away to call it catrinalis or

18:50

not quite? No.

18:54

It makes me feel better that

18:56

you also doubt your pronunciation. I've

18:59

never come across this organism before

19:02

and I haven't even come across

19:04

that genus before. Thank

19:06

you. Thank you so much. I

19:08

guess what? Do we make of

19:10

this and the significance of this organism?

19:12

Would we call it a deep

19:14

mycosis? Yeah. And is it how this

19:16

syndrome typically manifests itself? Well,

19:20

as we've said already, this is

19:22

an unusual organism and I think

19:24

it's been implied as well that

19:26

the world of mycology is forever

19:28

changing and it is difficult to

19:30

keep up with this kaleidoscopic landscape

19:32

of fungal nomenclature. But this syndrome

19:34

is indeed consistent with what we

19:36

call mysotoma. And whilst I am

19:38

no budding biologist. I

19:40

have done my research and we'll

19:42

talk a little bit about mysotoma

19:44

now. It is a chronic granulomatous

19:47

subcutaneous infection caused by several species

19:49

of fungi as well as soil

19:51

inhabiting bacteria, which is endemic within

19:53

this so -called mysotoma bells, which spans

19:55

from 15 degrees south to 30 degrees

19:57

north of the equator and really within

19:59

the tropics of the world. Sporadic

20:01

cases have been reported worldwide, including in

20:03

temperate regions, and it's really quite rare in

20:05

Australia when it does occur. It occurs

20:07

in the northern states and territories at which

20:09

you approach the tropics. We

20:11

make a distinction between actinomycetoma and

20:13

eomycetoma, the form of being caused by

20:15

soil inhabiting bacteria and the latter

20:17

from fungi, such as in this instance.

20:20

And the typical presentation is usually

20:22

with the triad of two

20:24

more sinus tracts. and macroscopic grains,

20:26

which are essentially colonies or

20:29

aggregates of the infectious organism. It

20:31

can extend to adjacent structures,

20:33

including bone, muscle, lymphatics. And

20:36

the classic description from a long,

20:38

long time ago was that of Madura

20:40

foot, named after a region in

20:42

the area called Madurai, where people would

20:44

have stepped on this fungal organism

20:46

that's quite disfiguring. Risk factors, as you

20:48

might gather, are typically environmental or

20:50

related to occupation, and thus it had

20:52

previously been known or sometimes is

20:54

known as an implantation mycosis. And

20:57

risk factors also include, such as

20:59

in this instance, states of immunocompromise, whether

21:01

they be inherited or required. The

21:04

mean age for this sort of syndrome

21:06

is in the 30s and typically occurs

21:08

in males with changing epidemiology based on

21:11

an itinerant population and other regions around

21:13

the world. It usually involves

21:15

the feasts as an implantation mycosis where workers

21:17

might be not wearing shoes and exposed

21:19

to thorns and other things within the soil.

21:21

and less likely to occur in parts

21:23

of the torso, the arms, and other parts

21:25

of the body. Common organisms

21:27

for mycetoma itself, or umycetoma, I

21:29

should say. Maderella mycetomatis, which is

21:31

the classic one, but it's worthwhile

21:34

noting that umycetoma itself is the

21:36

minority of cases of mycetoma. It's

21:38

35 % of cases of mycetoma across

21:40

the board. And within

21:42

umycetoma, Maderella mycetomacus accounts for

21:44

75 % of umycetoma, followed by

21:46

falciformer species. such as the

21:48

other ones that Katrina had

21:50

identified as being similar to

21:52

the falciformis spora lignitalis, which

21:54

was identified in this case.

21:57

And they tend to differ by local

21:59

epidemiology, including climate, vegetation, rainfall, and

22:01

different soil type. Little

22:03

is known about the incubation period between inoculation

22:05

and clinical manifestations, given that

22:07

many patients don't recall a specific predisposing injury,

22:09

such as in this instance. It's

22:12

worth noting that there are atypical

22:14

presentations that typically affect any compromised hosts,

22:16

whereby the classic triad might not

22:18

be present. There are numerous case reports

22:20

out there that highlight a link

22:22

with the tropics in transplant recipients or

22:24

those who are immunoprimised. For instance,

22:26

patients who have migrated from their country

22:28

of origin to a place that

22:30

is not within the mycetoma belt. Some

22:32

40 years later, they're receiving a

22:34

transplant and then having this fungus identified

22:36

from various parts of the body. But

22:39

there's really quite interesting cases

22:41

out there. So beyond clinical suspicion,

22:43

if someone came in with

22:45

a similar presentation, how would you

22:47

go? about

22:49

diagnosing mysotoma. It's

22:51

hard not to have a talk like this

22:53

without saying that clinical impression and an index of

22:55

suspicion are paramount. And they are. So

22:58

the presence of that triad are certainly things that

23:00

would give you an indication. But

23:02

beyond that, in terms of clinching

23:04

the diagnosis, it's a composite of

23:06

growing the organism and pursuing culture.

23:09

Whether that be with a fine needle

23:11

aspirate of growth, wherever it may be

23:13

on the body, with subsequent inoculation under

23:15

plates. I might ask you at this

23:17

instance, Katrina, I know you mentioned that

23:19

tend to culture these only at 30

23:22

degrees, but from my reading, sometimes these

23:24

get inoculated at both 30 degrees and

23:26

37 degrees for a number of weeks,

23:28

because different organisms within this, you must

23:30

atoma syndrome tend to grow predominantly different

23:32

temperatures. Is that fair to say or

23:34

something that always do? Yeah,

23:36

it is a fair enough

23:39

question. I guess we're

23:41

guided by standards for recommending

23:43

what? conditions we do grow

23:45

fungi at and certainly the guideline

23:47

we used is the CLSI guideline which

23:50

the people in the States would

23:52

be very well aware of and they

23:54

make the suggestion that whilst you

23:56

can put things at two different temperatures

23:58

and some labs do put things

24:00

at two different temperatures. Every

24:02

time you put more and more

24:04

plates out you dilute how much sample

24:06

you actually have to be able to

24:08

try and grow things. For

24:10

fungal work, the general recommendation is

24:12

you can just use 30 degrees.

24:15

But you've got to remember, there's also

24:17

plates that get set up for bacterial

24:20

cultures. And there's no reason why many

24:22

of these fungi wouldn't actually grow on

24:24

some of the bacterial plates as well. And

24:26

that is incubated at the higher temperature.

24:28

So we have in my own lab

24:30

times when we get something growing, but

24:32

it's also growing on the bacterial plates

24:34

as well. Great. Thanks

24:37

for that. So beyond culture, the other

24:39

things that are useful in establishing a

24:41

diagnosis include histopathology with evidence of chronic

24:43

granulomidus reaction, and possibly the presence of

24:45

a grain, which given how rare it

24:47

is ought to be discussed directly with

24:49

pathology at your own lab, given that

24:51

this has not seen a great deal.

24:53

And indeed, when we returned to the

24:55

histopathologists and asked them, was that bunch

24:57

of fungi you saw in a conglomerate

24:59

consistent with a grain? And when they

25:01

looked through their textbooks, they confirmed that

25:03

that indeed was the case. So, good

25:05

to have good relationships with the various

25:07

disciplines around the hospital. And

25:10

imaging is used sometimes to determine

25:12

extent of disease, whether it's invading in

25:14

surrounding tissues, but also to suggest

25:16

whether or not there may be improvements

25:18

to help guide duration of therapy.

25:20

I might ask Katrina, lastly, is there

25:22

anything in particular you would say

25:24

about sensitivities? I know we weren't unable

25:27

to achieve sporrelation in this instance,

25:29

but given this was a rare fungus

25:31

and something you hadn't quite encountered

25:33

before clinically. or at a lab level,

25:36

if you were even able to achieve

25:38

spirallation, would there be much to

25:40

be gleaned from undertaking sensitivity testing? Yeah,

25:43

so definitely we would try

25:45

and do susceptibility testing on

25:47

any fungus that grew from

25:49

and was deemed to be

25:51

significant. In this particular

25:53

case, because we couldn't get

25:55

spirallation, we couldn't do susceptibility

25:57

testing. If we had

25:59

been able to do susceptibility testing,

26:02

All we would be able to

26:04

give would be a value of

26:06

what the minimal inhibitory concentration was

26:08

for that particular isolate. But

26:10

that can often give clinicians

26:12

some confidence that whatever drug

26:14

they've decided to treat with,

26:16

you know, is likely to

26:18

be effective or not. There's

26:20

certainly no breakpoints available for

26:22

any of these unusual fungi.

26:24

We really only have breakpoints

26:26

available for one organism. and

26:28

one drug for aspergillus fumigatus

26:30

with boriconazole button. And we

26:33

don't really have breakpoints for anything else. So we're

26:35

really only going to be able to give you

26:37

a number, which may give you confidence as to

26:39

which drug can be used. From

26:41

my experience with testing allatomatiaceous

26:43

fungi, which grow in, you

26:45

know, from cases like this,

26:48

quite often itchoconazole is actually

26:50

really suggests that it is

26:52

quite an effective drug against

26:54

these dark, slow growing. I'm

26:58

not a clinician, but that

27:00

is kind of my experience in

27:03

the lab side of things. As

27:05

you say, I think as clinicians, we

27:07

quite enjoy MICs that are low numbers, but

27:09

appreciate that these are just environmental cutoffs.

27:11

It really comes down to trying to pick

27:14

what you think is going to be

27:16

the most effective agent. Yeah.

27:19

I think it'd be worth

27:22

emphasising that the biopsy is

27:24

ideally an excisional biopsy. because

27:26

it's unusual to get either

27:28

histological diagnosis or an effective

27:30

culture on either an FNA. Sometimes

27:34

a call biopsy, but in this instance,

27:36

we were fortunate enough to have the surgical

27:38

team perform a full excision. And

27:40

I think that's really led to

27:42

an expedited diagnosis in this case.

27:45

I completely agree with that, John. And

27:47

it's the same if we'd have to

27:49

go down the path of using, if

27:51

we hadn't managed to grow it, if

27:53

we'd gone down the path of having

27:56

to use PCR directly from the specimen.

27:58

your ability to get a positive, meaningful

28:00

result from a fine needle aspirate is

28:02

quite a lot lower than it would

28:04

be if you get a nice proper

28:06

tissue specimen. John, how did

28:08

you go on to choose your antifungal

28:11

therapy in this instance? Yeah, so

28:13

that was obviously a little bit

28:15

complicated in the sense that we

28:17

didn't have the full susceptibility data

28:19

to guide us. And

28:21

in these type of infections,

28:23

there's no prospective randomized clinical

28:25

trials to determine the most

28:28

effective drug therapy. But

28:30

we're used to dealing in

28:32

these, let's call it gray zones

28:34

for the theme today in

28:36

ID, where we have to treat

28:38

based on what's being reported

28:40

to work and what we have

28:42

familiarity with. I think

28:44

the surgical adjunctive therapy is really important

28:46

in these cases. If we can

28:48

get local control with the surgical excision,

28:51

then that should be emphasized. However,

28:53

we still wanted to pursue

28:55

some antimicrobial therapy in this

28:57

case. Just recalling

28:59

the case that it is a

29:02

transplant patient on tachyrolimus and everolimus. There

29:04

are a lot of drug

29:06

interactions to consider. And

29:09

reviewing all of the literature in

29:11

the past, a lot of the cases

29:13

have been treated, perhaps in more

29:15

resource -limited settings with ketoconazole, which we

29:17

would rarely use in our setting currently.

29:19

And then each reconnaisal has certainly

29:21

been used as Katrina alluded to. Many

29:24

of the newer studies where

29:26

there have been MYCs reported have

29:28

reported low values to the

29:30

newer triazoles such as vireconazole or

29:32

posiconazole. We did have some

29:34

experience with vireconazole in the past

29:36

with this patient, but perhaps

29:38

given that that was not that

29:41

long ago in a time

29:43

interval, we considered a new agent

29:45

perhaps being a better option

29:47

to switch to. So we decided

29:49

to use posiconazole. This

29:51

certainly had some significant drug

29:53

interactions and really reviewing this carefully

29:55

with our nephrology colleagues and

29:57

looking at the drug interactions. There's

30:00

a significant interaction with

30:02

the cytochrome P450 enzyme

30:04

subset 3A4. And

30:06

so we had to look

30:08

at that and the posiconazole was

30:10

expected to significantly interact

30:12

with dichrolimus so that the initial

30:14

dose of the dichrolimus had to be

30:17

about a third of the baseline

30:19

dosing and the everolimus had to be

30:21

about 50 % of the baseline dosing.

30:24

So the treatment was certainly initiated

30:26

in close consultation with the

30:28

nephrology team. We did that at

30:30

a time when they were

30:32

ready and able to do drug

30:34

levels quite frequently and the

30:36

dichrolimus actually had to come down

30:38

further. So this particular

30:40

patient was on 0 .5

30:42

milligrams BD which eventually

30:44

went down to 0 .05

30:47

milligrams BD in a stepwise

30:49

sequential fashion as the

30:51

levels stayed very high. So

30:54

whilst we look at reports of

30:56

what is expected, it's a lesson

30:58

that you always have to individualize

31:00

these drug -drug interactions. There

31:02

was no ongoing imaging really

31:04

for this particular site because

31:06

we could clinically feel it

31:08

and palpate it very nicely.

31:10

We did review a cerebral

31:12

image, just the completeness, because

31:15

some of these organisms have been known to disseminate

31:17

to the central nervous system, and that was novel.

31:20

And we did repeat his pulmonary

31:22

scan, which had the stable pulmonary

31:24

nodules from his previous pulmonary aspergillosis

31:26

with no change. So we elected

31:28

to treat for six months. This

31:30

was in the time where we

31:32

had another worldwide epidemic going on with

31:34

COVID. And so it was quite

31:36

challenging in terms of monitoring and clinic

31:39

visits, I'll be able to

31:41

get the patient in and

31:43

ensure that he remained symptom free

31:45

after successfully completing the treatment. Thanks

31:50

to Morgan, John, Max

31:52

and Katrina for joining February

31:54

today. Don't forget to check

31:56

out the website Februarypodcast .com where you

31:58

can find the consult notes, are

32:00

written supplements the episodes with links to

32:02

references, our library of ID

32:04

infographics and a link to our merch store.

32:07

February is produced with support from the

32:10

Infectious Diseases Society of America. Please

32:12

reach out if you have any suggestions

32:14

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with Febrile. Thanks for listening, stay safe,

32:18

and I'll see you next time.