JOURNAL OF CLINICAL MICROBIOLOGY, Feb. 2011, p. 752–756
Copyright © 2011, American Society for Microbiology. All Rights Reserved.
Vol. 49, No. 2
Disseminated Human Conidiobolomycosis Due
to Conidiobolus lamprauges?
Masatomo Kimura,1* Takashi Yaguchi,2Deanna A. Sutton,3Annette W. Fothergill,3
Elizabeth H. Thompson,3and Brian L. Wickes4
Department of Pathology, Kinki University Faculty of Medicine, Osaka-Sayama, Japan1; Medical Mycology Research Center, Chiba University,
Chiba, Japan2; and Fungus Testing Laboratory, Department of Pathology,3and Department of Microbiology and
Immunology,4University of Texas Health Science Center at San Antonio, San Antonio, Texas
Received 22 July 2010/Returned for modification 21 September 2010/Accepted 30 November 2010
We describe a disseminated fungal infection by Conidiobolus lamprauges in a patient with malignant lym-
phoma. Histopathology and mycological studies were performed, along with molecular analyses. This is the
first record of this species causing human disease and the fifth reported disseminated infection by a Conid-
iobolus sp. in humans.
A 61-year-old male Japanese office worker was diagnosed
with relapsed mantle cell lymphoma with bone marrow infil-
tration. Since repeated chemotherapy did not achieve com-
plete remission, the patient finally received a nonmyeloablative
allogeneic unrelated hematopoietic stem cell transplant. Short-
term methotrexate treatment was employed for graft-versus-
host disease prophylaxis. On day 7 posttransplant (PT), severe
(?0.1 ? 103neutrophils/?l) neutropenia was noted. Treat-
ment with broad-spectrum antibiotics and micafungin (150 mg/
day) was initiated for febrile neutropenia and continued until
day 20 PT. Neutrophil engraftment occurred on day 16 PT.
Cytomegalovirus antigenemia was detected and treated with
ganciclovir from day 39 until day 48 PT. On day 47 PT, pan-
creatitis developed and was treated with anticoagulant therapy
and anti-pancreatic-enzyme therapy for about a week. Treat-
ment with broad-spectrum antibiotics was started on the same
day and continued, using various antibiotics, until 4 days before
the patient died. A chest X-ray film demonstrated bilateral
lung infiltration on day 53 PT, with elevation of serum (133)-
?-D-glucan (BG) levels to 27.0 pg/ml (as determined by the
?-D-glucan Wako test) (Wako Pure Chemical Industries, To-
kyo, Japan) (normal levels ? 10 pg/ml). Since fungal infection
was suspected, treatment with micafungin (150 mg/day) was
restarted on day 53 PT. One week later, this was replaced by
treatment with liposomal amphotericin B (2.5 mg/kg/day) be-
cause a blood culture yielded Candida albicans and because the
serum BG levels had increased to 63.6 pg/ml. On day 62 PT,
treatment with hydrocortisone was initiated for hemophago-
cytic syndrome therapy. Treatment with pentamidine isethio-
nate was started on day 70 PT and continued until the death of
the patient, likely due to suspected Pneumocystis pneumonia.
On day 74 PT, antifungal therapy was switched from liposomal
amphotericin B to a combination of voriconazole (loading
dose, 6 mg/kg, followed by 4 mg/kg [administered intrave-
nously every 12 h]) and micafungin (150 mg/day) because the
serum BG levels had increased significantly to 2,366.0 pg/ml
and a chest X-ray film demonstrated additional widespread
pulmonary infiltration. Severe (?0.1 ? 103neutrophils/?l)
neutropenia due to hemophagocytic syndrome was recorded
from day 76 PT. The patient’s general condition worsened, and
the patient died of respiratory failure on day 80 PT.
An autopsy was performed 2 h and 36 min after death.
Pathological examination demonstrated that the mucosa of the
trachea and the main bronchi was eroded. All lobes of the
bilateral lungs were congested with irregular multiple hemor-
rhages and 5- to 10-mm-diameter nodular infarcts. Infarcts
were also found in the heart, bilateral kidneys, spleen, and
thyroid gland. A filamentous fungus (Conidiobolus lamprauges)
was isolated from the tissues of the tracheal mucosa and the
infarcted lesions presenting in the bilateral lungs, bilateral
kidneys, and spleen. Enterococcus faecium and Staphylococcus
aureus were cultured from the mucosa of the trachea, bilateral
lungs, and bilateral kidneys. E. faecium was also cultured from
the spleen and blood.
In microscopic analyses, fungal hyphae were found to be
proliferating in the tracheobronchial tissue and the lungs,
heart, kidneys, urinary bladder, urethra, spleen, and thyroid
gland, where they were markedly invading blood vessels. Con-
sequently, mycotic thrombi were frequently found, causing
nodular infarcts (Fig. 1A). There was no apparent inflamma-
tory cell infiltration in the lesions associated with fungal infec-
tion. There were two different types of hyphal morphology in
the tissue. One type was in the form of widely distributed
Mucorales-like broad (4- to 13-?m-wide) thin-walled paucisep-
tate hyphae with irregular branching (Fig. 1B). These were
often wrinkled, folded, and twisted, and the tips of the hyphae
sometimes showed unusual bulbous dilation (21 to 40 ?m in
diameter) (Fig. 1C). The other type was represented by dichot-
omously branching 5- to 7-?m-wide septate hyphae with par-
allel sides resembling those of Aspergillus morphology; these
were mostly seen in the mycotic thrombi (Fig. 1D). None of the
hyphae in the tissue were coated by a deposit of eosinophilic
Splendore-Hoeppli material. The liver, gallbladder, alimentary
* Corresponding author. Mailing address: Department of Pathology,
Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-
Sayama, Osaka 589-8511, Japan. Phone: 81-72-366-0221, ext. 3142,
3141. Fax: 81-72-360-2028. E-mail: firstname.lastname@example.org.
?Published ahead of print on 8 December 2010.
tract, and genital organs were spared fungal infection. No
lymphoma cells were detected in any of the tissues examined.
An autopsy isolate recovered from the pulmonary lesions
was forwarded to the Fungus Testing Laboratory at the
University of Texas Health Science Center at San Antonio
(UTHSCSA) (TX) for morphological and molecular char-
acterization and was added to their culture collection under
accession number UTHSC R-4463. Morphological and tem-
peratures studies were conducted on potato flakes agar
(PFA) prepared in-house. Colony diameters were measured
on 100-mm-diameter petri dishes incubated at 24, 36.5, 40,
45, and 50°C. Growth was rapid, and colonies were pale,
thin, effuse, and glabrous within the first 72 h (Fig. 2A), with
average colony diameters at 24, 48, and 72 h as follows: at
FIG. 1. Histopathology of Conidiobolus lamprauges invading pulmonary tissue. (A) The vascular lumen is occluded by a mycotic thrombus
composed of numerous hyphae. (Grocott staining; bar, 100 ?m.) (B) Hyphae showing irregular branching with frequent wavy shapes characteristic
of Mucorales hyphae. (Grocott staining; bar, 20 ?m). (C) The tips of many hyphae show unusual bulbous dilation. Nondilated hyphal portions are
continuous with the dilated portions. (Grocott staining; bar, 25 ?m). (D) Proliferating hyphae, resembling Aspergillus hyphae, in a vascular lumen.
The hyphae are septate, have parallel sides, and branch dichotomously at acute angles. (Grocott staining; bar, 25 ?m).
FIG. 2. Colonial morphology of Conidiobolus lamprauges on PFA after 72 h of incubation at 36.5°C. (A) The colony is pale, thin, effuse, and
glabrous. (B) Lid of petri dish, demonstrating forcibly discharged conidia of Conidiobolus lamprauges.
VOL. 49, 2011CASE REPORTS 753
24°C, 10 mm, 25 mm, and 33 mm, respectively; at 36.5°C, 23
mm, 40 mm, and 52 mm, respectively; and at 40°C, 20 mm,
32 mm, and 40 mm, respectively. The lid of the petri dish
demonstrated forcibly discharged conidia (Fig. 2B). No
growth occurred at 45 or 50°C after 72 h. The isolate also
failed to grow on media containing 10 ?g/ml benomyl, pre-
pared in-house, but did exhibit growth on media containing
0.04% cycloheximide (Remel, Lenexa, KS). Colonies be-
came pale yellowish-beige with extended incubation. Micro-
scopic features observed on a PFA slide culture preparation
and tease mounts in lactophenol cotton blue are shown in
Fig. 3 and included conidiophores (4.8 to 7.2 ?m in width)
and primary conidia prior to release (Fig. 3A); zygospores
(14 to 29 ?m, with an average diameter of 24 ?m) contain-
ing a large globule and a single papillate primary conidium
(15 ?m in diameter) (Fig. 3B); an immature zygospore
formed between two hyphal segments (Fig. 3C); hyphae,
zygospores (with large globules), and primary conidia, one
of which showed migration of the cytoplasm from the pri-
mary conidium into the secondary replicative conidium (Fig.
3D); and zygospores and conidia visible at lower magnifica-
tion (Fig. 3E). Villose conidia and multireplicative conidia
were absent. Our isolate was microscopically identical to
those reported by others using the features proposed by
Vilela et al. (14). On the basis of the macroscopic, micro-
scopic, and physiologic features cited above, the isolate was
morphologically identified as C. lamprauges. The isolate has
been deposited into the University of Alberta Microfungus
Collection and Herbarium under accession number UAMH
11219 and the Medical Mycology Research Center, Chiba
University, Japan, under accession number IFM58391.
Isolates were prepared for sequence analysis first by subcul-
ture onto potato dextrose agar (PDA) plates and then by
incubation for 24 h at 30°C. Template DNA was isolated from
PDA plates as described previously (12). PCR was performed
using template DNA and primers ITS1 and NL4 to amplify a
single contig containing the internal transcribed spacer (ITS)
and D1-D2 regions, and the amplified material was then se-
quenced on both strands with primers ITS1, ITS4, NL1, and
NL4 at the UTHSCSA Advanced Nucleic Acids Core Facility
(12). The ITS and D1-D2 sequences were then used to search
the GenBank database at the NCBI website (http://blast.ncbi
.nlm.nih.gov/Blast.cgi) using the BLASTn algorithm. Results
were sorted according to the percentage of maximum identity
and were considered significant for query coverage of ?90%
and maximum identity of ?97%. The top four hits from the
ITS BLASTn search were all for C. lamprauges (accession
numbers GQ478279, GQ478280, GQ478281, and AF296754)
at 100%, 100%, 99%, and 99% identities, respectively, with
hits ranging from 749 of 750 bp to 750 of 750 bp. The next
closest ITS hit was Schizangiella serpentis at 90% identity but
only 79% query coverage. The D1-D2 search returned nine
Conidiobolus hits, with the top hit being C. lamprauges at
100% identity and 100% query coverage (accession number
AF113458), with 643 of 643 bp matching. The remaining
Conidiobolus species (C. thromboides, C. osmodes, C. ant-
arcticus, and C. pumilus) all displayed identities of ?84%
and query coverage of 80% or less and were therefore not
FIG. 3. Microscopic morphology of Conidiobolus lamprauges. (A) Conidiophore and primary conidium prior to release. (B) Zygospores
containing a large globule and a single papillate primary conidium. (C) Immature zygospore formed between two hyphal segments. (D) Hyphae,
zygospores (with large globules), and primary conidia, one of which shows migration of the cytoplasm from the primary conidium into the
secondary replicative conidium. (E) Zygospores and conidia at lower magnification.
754 CASE REPORTS J. CLIN. MICROBIOL.
considered significant. Based on the BLASTn search, the
identity of our isolate, UTHSC R-4463, was consistent with
C. lamprauges. (Sequence data have been deposited in the
GenBank database; see below).
Antifungal susceptibility testing was performed according
to the guidelines outlined in the CLSI M38-A2 document
(2). The concentration of the inoculum was analyzed using a
spectrophotometer and then adjusted to a final value of 1 to
5 ? 104CFU/ml in RPMI 1640 medium. The inoculum was
then added to round-bottomed microtiter wells containing
various concentrations of antifungal agents, including am-
photericin B (AMB), anidulafungin (ANID), caspofungin
(CAS), micafungin (MICA), itraconazole (ITC), voricon-
azole (VRC), posaconazole (POSA), miconazole (MON),
and terbinafine (TRB). Plates were incubated at 35°C for
48 h, with endpoint readings determined at both the 24- and
48-h time points. The endpoint was determined as the low-
est concentration that completely inhibited growth (AMB,
ITC, VRC, and POSA), that resulted in a 50% inhibition of
growth (MON and TRB), or that resulted in aberrant
growth (ANID, CAS, and MICA) (i.e., the minimum effec-
tive concentration [MEC]). Combination testing was accom-
plished for ITC plus TRB and for POSA plus TRB. Param-
eters outlined in the M38-A2 document were used in the
checkerboard dilution format. Since different endpoints
were assessed for TRB versus the azoles when individual
drug activity was assessed, the more stringent 100% inhibi-
tion endpoint value was used in determining endpoints for
combination studies. The results obtained at 24 and 48 h,
respectively, were as follows: AMB, 4 and 8 ?g/ml; ANID,
?8 ?g/ml; CAS, ?8 ?g/ml; MICA, ?8 ?g/ml; ITC, 0.5 and
1 ?g/ml; POSA, 4 and 4 ?g/ml; VRC, ?16 ?g/ml; MON,
0.25 and 1 ?g/ml; and TRB, 0.03 and 0.125 ?g/ml. Although
no breakpoints have been defined for this organism, inter-
pretive guidelines based upon achievable drug concentra-
tions suggest resistance to all agents in vitro, possibly ex-
cluding ITC, MON, and TRB. Results of synergy studies
with ITC and TRB at 1 and 0.06 ?g/ml and POSA and TRB
at ?0.03 and 0.125 ?g/ml were interpreted as indifferent
(i.e., neither synergistic nor antagonistic).
Discussion. Conidiobolomycosis is an infectious disease
caused by a fungus belonging to the genus Conidiobolus within
the order Entomophthorales and in the class Zygomycetes (7).
Members of the genus Conidiobolus are generally considered
saprobes distributed in plant detritus and soil (7, 11, 13). Three
species in the genus Conidiobolus are known to cause diseases
in humans or animals: C. coronatus, C. incongruus, and C.
lamprauges (5, 7, 14). This report is the first record of C.
lamprauges causing human disease and the fifth reported dis-
seminated infection caused by a Conidiobolus sp. in humans.
Human infection with Conidiobolus species occurs most com-
monly as chronic rhinofacial mycosis in otherwise healthy hosts
(7, 11). Disseminated human infections have previously been
described in only four cases, with the etiological agent being C.
incongruus in two cases, C. coronatus in one case, and an
unidentified Conidiobolus sp. in the other case (1, 6, 15, 16). C.
lamprauges has previously been implicated as the causative
agent of nasopharyngeal infection in horses and sheep (5, 14).
The modes of infection by C. lamprauges were quite different
between these animal cases and the present human case. These
differences may be related to factors such as the host immune
status, human susceptibility to certain strains, and the ability of
these strains to adhere to human tissues. The patient described
in this case report was immunocompromised, and that may
have been a predisposing factor in disseminated infection. In
addition, the ability of our strain to invade blood vessels might
have been superior to that of animal strains.
The mode of transmission of the Conidiobolus species was
not established in the present case. Since C. lamprauges is
usually found in leaf litter and soil (13), inhalation of its air-
borne conidia could have been the route of transmission in this
case. This possibility was supported by the autopsy finding of
tracheobronchial erosion with fungal invasion and bilateral
fungal pneumonia. Given that the patient had been hospital-
ized for approximately 50 days before the detection of pulmo-
nary infiltrate on a chest X-ray film and the elevation of the
serum BG level, this infection may have been acquired in the
hospital. However, there was no apparent event, such as on-
going hospital construction, that might have resulted in pollu-
tion of the room air with fungal elements.
An important laboratory finding in the present case was the
detection of serum BG, and its increased level, along with the
burden of infection. BG is a cell wall polysaccharide compo-
nent of most fungi and can be detected in the bloodstream of
patients with fungal infections (8). It can be a surrogate marker
of invasive fungal infections, and its monitoring helps to assess
the effectiveness of antifungal therapy (10). Since the zygomy-
cetes and Cryptococcus species have lower BG content, BG
detection assays are often less useful (9). Even though Conid-
iobolus species are members of the zygomycetes, the serum BG
in this patient increased to an extremely high level. To date,
there have been no other reports regarding serum BG levels
during conidiobolomycosis, and more cases need to be accu-
mulated before serum BG levels during conidiobolomycosis
can be thoroughly assessed.
The most interesting histological point raised by the present
case was that the fungal hyphae of the Conidiobolus species
masqueraded as both Mucorales and Aspergillus species in tis-
sue. Widely distributed hyphae were thin-walled, broad, and
pauciseptate, with irregular branching, resembling the hyphae
of species of Mucorales. The same features have been de-
scribed in reports of three previous immunocompromised pa-
tients with disseminated conidiobolomycosis (6, 15, 16). Due to
the shape of the hyphae and the lack of Splendore-Hoeppli
material surrounding them, Conidiobolus hyphae are indistin-
guishable from those of the Mucorales species in tissue. In
contrast, many of the hyphae proliferating in the vascular lu-
mens were uniform and septate with dichotomous branching
(Fig. 1D), resembling those of Aspergillus species. Thus, histo-
logic features must be interpreted with caution.
Although Vilela et al. (14) showed colonies with “radial
folds,” no such colony morphology was observed in our case.
Colonial morphology is often dependent on the media used,
and the photomicrographs by Vilela et al. (14) were taken on
Sabouraud dextrose agar versus the PFA used in our case,
possibly explaining these differences. It should also be noted
that the radial folds they describe are more evident with ex-
VOL. 49, 2011CASE REPORTS755
tended incubation (i.e., 6 days), whereas our images were re-
corded at 3 days. A key feature in the presumptive morpho-
logical identification of both Conidiobolus and Basidiobolus
spp. is the detection of forcibly discharged conidia on the lid of
the petri dish (Fig. 2B). The finding of a single, large globule
within mature zygospores (Fig. 3B, D, and E), a feature not
present within those of either C. incongruus or C. coronatus,
serves as a presumptive identification of C. lamprauges. Our
isolate was microscopically identical to those reported by oth-
ers using the features proposed by Vilela et al. (14).
There is no consensus regarding the appropriate antifungal
treatment for Conidiobolus infection. Cotrimoxazole, AMB,
and AMB with flucytosine have each been used against dis-
seminated infection but with no success (1, 15, 16). The present
fungal infection did not respond to therapy that should have
been effective against Mucorales and Aspergillus species. Our
in vitro antifungal susceptibility studies suggested that our iso-
late was multidrug resistant, explaining the therapy failure.
The in vitro antifungal susceptibilities of seven isolates belong-
ing to Conidiobolus spp., including one isolate of C. lam-
prauges, to six antifungals (AMB, ketoconazole, MON, ITC,
fluconazolem and flucytosine) were tested by Guarro et al., and
all of the isolates were resistant to all of the antifungals (4).
The results of our synergy studies performed with ITC plus
TRB at 1 plus 0.06 ?g/ml and POSA plus TRB at ?0.03 plus
0.125 ?g/ml were interpreted as indifferent (i.e., neither syn-
ergistic nor antagonistic). According to a recent clinical report,
treatment with a combination of ITC and TRB resulted in the
successful treatment of rhinofacial C. coronatus infection, al-
though in vitro susceptibility testing of the isolate revealed
resistance to both ITC and TRB (3). Since such combination
therapy is effective in some cases, synergy studies should be
In conclusion, C. lamprauges is a new addition to the species
of Conidiobolus recognized as capable of causing vascular in-
vasion and fatal disseminated disease in humans.
Nucleotide sequence accession numbers. Sequence data
have been deposited in the GenBank database under accession
numbers HM593511 (ITS sequence) and HM593512 (D1/D2
We thank Yuko Tsubakimoto, Department of Clinical Laboratory,
Kinki University Hospital (Osaka, Japan), for isolating the fungus, and
Anna M. Romanelli, Department of Microbiology and Immunology,
University of Texas Health Science Center (San Antonio, TX), for
carrying out the sequencing studies.
B.L.W. was supported by grant PR054228 from the U.S. Army
Medical Research and Material Command, Office of Congressionally
Directed Medical Research Programs.
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756CASE REPORTS J. CLIN. MICROBIOL.