# Molecular Identification and Susceptibility of Clinically RelevantScedosporium spp. in China

Authors: Hong Wang; Zhe Wan; Ruoyu Li; Qiaoyun Lu; Jin Yu
Journal: BioMed Research International
 (2015)

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## Abstract

As various new sibling species within theScedosporium spp. have been described recently, this study was conducted to investigate distribution and antifungal susceptibility profiles of the different species of Scedosporium spp. in China. Twenty-one clinical strains of Scedosporium from China and two strains from Japan were reidentified by MLSA. The analysis included BT2, CAL, RPB, SOD, and ACT and the combination of the five loci. Pseudallescheria boydii complex (17 strains) and S. apiospermum (6 strains) were identified. P. boydii complex included four closely related subgroups: P. boydii (9 strains), P. ellipsoidea (6 strains), P. fusoidea (1 strain), and P. angusta (1 strain). There were no significant differences in MICs for neither VOR, POS, nor AMB over all the five species in study. For itraconazole, intraspecific diversity was evident.


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## Body

## 1. Introduction

Scedosporium spp. is one of the species of the opportunistic pathogenic fungi that can always be found in environment, especially in sewerage. It infects immunocompromised patients and drowning men, involving lungs, sinuses, bones, joints, eyes, and brain [1].In recent years, members of the genusScedosporium are increasingly recognized as opportunistic agents of disease, for example, in transplant recipients.Scedosporium species have been identified as the second most prevalent mold afterAspergillus colonizing the lungs of patients with cystic fibrosis [2].Scedosporium infections occur worldwide. In European countries, USA and Australia,Scedosporium species were always found in patients with chronic lung diseases, cystic fibrosis (CF), lung or allogenic bone-marrow transplantation, and hematologic malignancies [1, 3, 4]. Accordingly, the common types were pulmonary, nasal sinuses, skin/soft tissues, CNS, and disseminated infection [1, 3, 4].It is traditionally recognized thatPseudallescheria boydii is the sexual stage of theS. apiospermum. However, recent molecular studies [5–7] showed thatScedosporium is a species complex comprising at least five distinct groups:S. aurantiacum,P. minutispora,S. dehoogii,S. apiospermum, andP. boydii, the last group consisting of four closely related subgroups calledP. boydii,P. angusta,P. ellipsoidea, andP. fusoidea. Furthermore,S. prolificans is now renamed asLomentospora prolificans [8]. It is important to identifyScedosporium spp. to species level because their virulence, metabolic trait, andin vitro susceptibility may be various based on their different species [3–9].


## 2. Materials and Methods

### 2.1. Strains

From 1990 to 2014, twenty-oneScedosporium strains isolated from patients were reserved in Research Center for Medical Mycology at Peking University. The clinical samples were collected from 14 Chinese hospitals which located mainly in central and south of China. All the isolates were identified asS. apiospermum orP. boydii by morphology. A total of 23 isolates (including two strains from Japan) as shown in Table 1 were investigated in this study. Furthermore,in vitro susceptibility was performed on the same set strains.Table 1
Origin, sequence data, and species identification of studied isolates.
BMU number
Clinical sample
GenBank accession number
Molecular identification
BT2
CAL
RPB
SOD
ACT
00488
Unknown
KP981202
KP981130
KP981185
KP981153
KP981107
P. boydii
00491∗
Unknown
KP981214
KP981131
KP981179
KP981154
KP981108
S. apiospermum
01112
Unknown
KP981203
KP981132
KP981192
KP981155
KP981109
P. boydii
01113
Unknown
KP981204
KP981133
KP981181
KP981156
KP981110
P. boydii
01114
Unknown
KP981199
KP981134
KP981193
KP981157
KP981111
P. boydii
01115
Unknown
KP981200
KP981135
KP981194
KP981158
KP981112
P. angusta
01116
Unknown
KP981201
KP981136
KP981186
KP981159
KP981113
P. boydii
01117
Eye ball
KP981205
KP981138
KP981180
KP981160
KP981114
S. apiospermum
01118
Unknown
KP981215
KP981137
KP981190
KP981161
KP981115
P. ellipsoidea
01272
Sputum
KP981206
KP981139
KP981182
KP981162
KP981116
P. boydii
01297∗
Unknown
KP981221
KP981140
KP981195
KP981163
KP981117
P. fusoidea
02948
Nasal sinus
KP981211
KP981141
KP981196
KP981164
KP981118
P. boydii
03882
Sputum
KP981207
KP981142
KP981176
KP981165
KP981119
S. apiospermum
04111
Joint fluid
KP981219
KP981143
KP981178
KP981166
KP981120
S. apiospermum
04729
BALF
KP981216
KP981144
KP981198
KP981167
KP981121
S. apiospermum
04730
Nasal sinus
KP981217
KP981145
KP981191
KP981168
KP981122
P. ellipsoidea
04772
CSF
KP981220
KP981146
KP981183
KP981169
KP981123
P. ellipsoidea
04780
BALF
KP981218
KP981147
KP981187
KP981170
KP981124
P. ellipsoidea
05145
Unknown
KP981213
KP981148
KP981189
KP981171
KP981125
P. ellipsoidea
07108
Sputum
KP981208
KP981149
KP981188
KP981172
KP981126
P. ellipsoidea
07224
Brain
KP981209
KP981150
KP981184
KP981173
KP981127
P. boydii
07374
Pus
KP981212
KP981151
KP981197
KP981174
KP981128
P. boydii
07462
CSF
KP981210
KP981152
KP981177
KP981175
KP981129
S. apiospermum
∗Strains from Japan.


### 2.2. Molecular Studies

The isolates were cultured on PDA at 28°C for 7 days. For fungal DNA extraction, glass beads method previously described by van Burik et al. was followed [10]. Adapted from earlier genotyping studies [11–14], PCR amplification with different primer pairs was attempted forScedosporium species for the following genes: β-tubulin (BT2, exons 2–4) [11], calmodulin (CAL, exons 3–4) [12], the second largest subunit of RNA polymerase II (RPB) [13], superoxide dismutase (SOD), and actin (ACT) [14].The PCR assay (25μL) included 2 μL of fungal DNA extract, 1 μM of each gene-specific primer, 2.5 mmol dNTP Mix 1 μL, 10x PCR buffer 2.5 μL, and LA Taq polymerase 0.25 μL (Fermentas, St. Leon-Rot, Germany). The amplification for all targeted genes was performed in a Eppendorf PCR machine (AG22331) as follows: 5 min of initial denaturation at 95°C, followed by 35 cycles at 95°C for 30 s, gene-specific annealing temperature for 30 s, and 72°C for 1 min (for RPB2 the annealing time was 2.5 min). The PCR products were visualized by electrophoresis on a 1% (w/v) agarose gel. Both strands of the PCR fragments were sequenced using the above-mentioned primers. The consensus sequences were obtained using SeqMan (DNAStar-Lasergene, Madison, WI, USA) software. Newly obtained sequences were deposited in GenBank under accession numbers KP 981107 to KP 981221 (Table 1). They were used to conduct alignment analysis for preliminary species identification in the NCBI genomic database (http://blast.ncbi.nlm.nih.gov/) and CBS database (http://www.cbs.knaw.nl/). The sequences were aligned using MUSCLE. For the maximum likelihood analysis, the distances between sequences were calculated using the best parameter model found by MEGA 6.0 6 (http://www.megasoftware.net/). A bootstrap analysis was conducted with 1000 replications.


### 2.3. Susceptibility Test

Thein vitro susceptibility of the 23Scedosporium isolates against four antifungal agents was evaluated by using the Clinical and Laboratory Standards Institute (CLSI) M38-A2 broth microdilution method [15]. The inocula suspensions were prepared in new sterile tubes and adjusted to 0.4−5 × 106 colony-forming units per milliliter (CFU/mL) by counting spores in a hemocytometer and subsequently verifying them through quantitative colony counts on PDA plates. The nongerminated spore suspensions were diluted 1 : 100 in an RPMI 1640 to achieve a final inoculum concentration of 0.4–5 × 104 CFU/mL. The following antifungal agents were used: voriconazole (VOR; Shouguang Fukang Pharmaceutical Co., Ltd., China), posaconazole (POS; Merck, Rahway, NJ, USA), itraconazole (ITR; Shouguang Pharm), and amphotericin B (AMB; Sigma-Aldrich Co., St. Louis, USA). They were all diluted in 100% dimethyl sulphoxide as a stock solution with a concentration of 1.600 mg/L. Final drug concentrations ranged from 16 to 0.03 mg/L for all the four drugs. The minimal inhibitory concentrations (MIC) endpoints were defined as the lowest concentration at which there was a complete inhibition of growth.Aspergillus flavus ATCC 204304 served as a quality control strain. The microtiter panels were incubated at 35°C and the results were read after 72 h. All tests were performed in triplicate on three different days.


## 2.1. Strains

From 1990 to 2014, twenty-oneScedosporium strains isolated from patients were reserved in Research Center for Medical Mycology at Peking University. The clinical samples were collected from 14 Chinese hospitals which located mainly in central and south of China. All the isolates were identified asS. apiospermum orP. boydii by morphology. A total of 23 isolates (including two strains from Japan) as shown in Table 1 were investigated in this study. Furthermore,in vitro susceptibility was performed on the same set strains.Table 1
Origin, sequence data, and species identification of studied isolates.
BMU number
Clinical sample
GenBank accession number
Molecular identification
BT2
CAL
RPB
SOD
ACT
00488
Unknown
KP981202
KP981130
KP981185
KP981153
KP981107
P. boydii
00491∗
Unknown
KP981214
KP981131
KP981179
KP981154
KP981108
S. apiospermum
01112
Unknown
KP981203
KP981132
KP981192
KP981155
KP981109
P. boydii
01113
Unknown
KP981204
KP981133
KP981181
KP981156
KP981110
P. boydii
01114
Unknown
KP981199
KP981134
KP981193
KP981157
KP981111
P. boydii
01115
Unknown
KP981200
KP981135
KP981194
KP981158
KP981112
P. angusta
01116
Unknown
KP981201
KP981136
KP981186
KP981159
KP981113
P. boydii
01117
Eye ball
KP981205
KP981138
KP981180
KP981160
KP981114
S. apiospermum
01118
Unknown
KP981215
KP981137
KP981190
KP981161
KP981115
P. ellipsoidea
01272
Sputum
KP981206
KP981139
KP981182
KP981162
KP981116
P. boydii
01297∗
Unknown
KP981221
KP981140
KP981195
KP981163
KP981117
P. fusoidea
02948
Nasal sinus
KP981211
KP981141
KP981196
KP981164
KP981118
P. boydii
03882
Sputum
KP981207
KP981142
KP981176
KP981165
KP981119
S. apiospermum
04111
Joint fluid
KP981219
KP981143
KP981178
KP981166
KP981120
S. apiospermum
04729
BALF
KP981216
KP981144
KP981198
KP981167
KP981121
S. apiospermum
04730
Nasal sinus
KP981217
KP981145
KP981191
KP981168
KP981122
P. ellipsoidea
04772
CSF
KP981220
KP981146
KP981183
KP981169
KP981123
P. ellipsoidea
04780
BALF
KP981218
KP981147
KP981187
KP981170
KP981124
P. ellipsoidea
05145
Unknown
KP981213
KP981148
KP981189
KP981171
KP981125
P. ellipsoidea
07108
Sputum
KP981208
KP981149
KP981188
KP981172
KP981126
P. ellipsoidea
07224
Brain
KP981209
KP981150
KP981184
KP981173
KP981127
P. boydii
07374
Pus
KP981212
KP981151
KP981197
KP981174
KP981128
P. boydii
07462
CSF
KP981210
KP981152
KP981177
KP981175
KP981129
S. apiospermum
∗Strains from Japan.


## 2.2. Molecular Studies

The isolates were cultured on PDA at 28°C for 7 days. For fungal DNA extraction, glass beads method previously described by van Burik et al. was followed [10]. Adapted from earlier genotyping studies [11–14], PCR amplification with different primer pairs was attempted forScedosporium species for the following genes: β-tubulin (BT2, exons 2–4) [11], calmodulin (CAL, exons 3–4) [12], the second largest subunit of RNA polymerase II (RPB) [13], superoxide dismutase (SOD), and actin (ACT) [14].The PCR assay (25μL) included 2 μL of fungal DNA extract, 1 μM of each gene-specific primer, 2.5 mmol dNTP Mix 1 μL, 10x PCR buffer 2.5 μL, and LA Taq polymerase 0.25 μL (Fermentas, St. Leon-Rot, Germany). The amplification for all targeted genes was performed in a Eppendorf PCR machine (AG22331) as follows: 5 min of initial denaturation at 95°C, followed by 35 cycles at 95°C for 30 s, gene-specific annealing temperature for 30 s, and 72°C for 1 min (for RPB2 the annealing time was 2.5 min). The PCR products were visualized by electrophoresis on a 1% (w/v) agarose gel. Both strands of the PCR fragments were sequenced using the above-mentioned primers. The consensus sequences were obtained using SeqMan (DNAStar-Lasergene, Madison, WI, USA) software. Newly obtained sequences were deposited in GenBank under accession numbers KP 981107 to KP 981221 (Table 1). They were used to conduct alignment analysis for preliminary species identification in the NCBI genomic database (http://blast.ncbi.nlm.nih.gov/) and CBS database (http://www.cbs.knaw.nl/). The sequences were aligned using MUSCLE. For the maximum likelihood analysis, the distances between sequences were calculated using the best parameter model found by MEGA 6.0 6 (http://www.megasoftware.net/). A bootstrap analysis was conducted with 1000 replications.


## 2.3. Susceptibility Test

Thein vitro susceptibility of the 23Scedosporium isolates against four antifungal agents was evaluated by using the Clinical and Laboratory Standards Institute (CLSI) M38-A2 broth microdilution method [15]. The inocula suspensions were prepared in new sterile tubes and adjusted to 0.4−5 × 106 colony-forming units per milliliter (CFU/mL) by counting spores in a hemocytometer and subsequently verifying them through quantitative colony counts on PDA plates. The nongerminated spore suspensions were diluted 1 : 100 in an RPMI 1640 to achieve a final inoculum concentration of 0.4–5 × 104 CFU/mL. The following antifungal agents were used: voriconazole (VOR; Shouguang Fukang Pharmaceutical Co., Ltd., China), posaconazole (POS; Merck, Rahway, NJ, USA), itraconazole (ITR; Shouguang Pharm), and amphotericin B (AMB; Sigma-Aldrich Co., St. Louis, USA). They were all diluted in 100% dimethyl sulphoxide as a stock solution with a concentration of 1.600 mg/L. Final drug concentrations ranged from 16 to 0.03 mg/L for all the four drugs. The minimal inhibitory concentrations (MIC) endpoints were defined as the lowest concentration at which there was a complete inhibition of growth.Aspergillus flavus ATCC 204304 served as a quality control strain. The microtiter panels were incubated at 35°C and the results were read after 72 h. All tests were performed in triplicate on three different days.


## 3. Results

### 3.1. Molecular Phylogeny

We were able to amplify and sequence 470 bp, 645 bp, 935 bp, 775 bp, and 396 bp of the BT2, CAL, RPB, ACT, and SOD loci, respectively. Of the 3221 nucleotides sequenced, 209 (6.5%) were informative for parsimony in the differentScedosporium isolates. For identification, reference sequence ofScedosporium species available in public database were used including BT2 and CAL, but no sequences for RPB, SOD, and ACT were available. The sequences for BT2, CAL, RPB, SOD, and ACT yielded phylogenetic trees with the same topology (Figures 1–5). In the combination phylogenetic trees based on BT2 and CAL (Figure 6), 23 strains in our study were reidentified to the species level according to the reference strains, which were analyzed in the Gilgado literature.P. boydii (9/23) and its closely related subtypesP. ellipsoidea (6/23),P. fusoidea (1/23), andP. angusta (1/23) were the most common, and the other 6 of 23 strains were identified asS. apiospermum.Figure 1
Maximum likelihood tree based on BT2 sequences. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.Figure 2
Maximum likelihood tree based on CAL sequences. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.Figure 3
Maximum likelihood tree based on RPB. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.Figure 4
Maximum likelihood tree based on SOD sequences. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.Figure 5
Maximum likelihood tree based on ACT sequences. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.Figure 6
Maximum likelihood tree based on the analysis produced from the combined BT2 and CAL data. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.The topology of the combined tree (Figure7) of all five loci was similar to those observed in the trees of individual locus and the combined tree of BT2 and CAL. Four principal clades were obtained. The four clades were theP. boydii clade,P. ellipsoidea clade,P. fusoidea/P. angusta clade, andS. apiospermum clade.P. fusoidea andP. angusta always assemble together, andP. boydii andP. ellipsoidea were very closely related.S. apiospermum has the highest intraspecies variability (genetic distance = 0.008), which is comparable to the interspecies variability betweenP. fusoidea andP. angusta (genetic distance = 0.008).Figure 7
Maximum likelihood tree based on the analysis produced from the combined all five markers data. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.


### 3.2.In Vitro Susceptibility Test

The MIC values for the four antifungal agents examined by the CLSI M-38A2 microdilution method against the 23 strains are presented in Table2. VOR was the most active agent against all 23 strains with a MIC range from 0.25 to 1 μg/mL and a 0.46 μg/mL GM. POS was the second most active agent with MIC values of 2 or 4 μg/mL. For ITR, the intraspecific diversity was obvious as most strains had a MIC between 2 and 4 μg/mL, but five strains were higher at a MIC of 32 μg/mL. AMB is the least effective with high MIC values ranging from 4 to 32 μg/mLin vitro.Table 2
In vitro susceptibility of 23 Scedosporium strains studied in this paper.
Strain species
Strain ID number
MIC (μg/mL)
VOR
POS
ITR
AMB
P. boydii
BMU 00488
0.25
2
4
4
BMU 01112
0.25
2
2
32
BMU 01113
0.25
4
4
32
BMU 01114
0.5
2
4
8
BMU 01116
0.5
2
4
4
BMU 01272
0.5
2
2
8
BMU 02948
0.5
2
2
4
BMU 07224
0.25
2
4
16
BMU 07374
0.25
2
4
4
P. ellipsoidea
BMU 01118
1
4
32
4
BMU 04730
0.5
2
2
4
BMU 04772
0.5
4
32
32
BMU 04780
0.5
4
4
16
BMU 05145
0.5
4
32
8
BMU 07108
0.25
4
4
8
P. angusta
BMU 01115
0.5
2
4
8
P. fusoidea
BMU 01297
0.5
2
2
32
S. apiospermum
BMU 00491
0.5
4
4
4
BMU 01117
0.5
4
4
8
BMU 03882
0.5
2
4
8
BMU 04111
1
4
32
16
BMU 04729
0.5
2
2
8
BMU 07462
1
2
32
8The MIC50 and MIC90 for the four antifungal agents againstP. boydii,P. ellipsoidea, andS. apiospermum are presented in Table 3. There were similar MIC50 and MIC90 for VOR, POS, or AMB of the three species above. For ITR, the MIC90 ofP. boydii (4 μg/mL) was lower than that ofP. ellipsoidea (32 μg/mL) andS. apiospermum (32 μg/mL).Table 3
The MIC50 and MIC90 for the four antifungal agents against P. boydii, P. ellipsoidea, and S. apiospermum.
Species  (number of isolates)
Drug concentration (μg/mL)
VOR
POS
ITR
AMB
MIC50
MIC90
MIC50
MIC90
MIC50
MIC90
MIC50
MIC90
P. boydii(9)
0.25
0.5
2
4
4
4
8
32
P. ellipsoidea (6)
0.5
1
4
4
4
32
8
32
S. apiospermum (6)
0.5
1
2
4
4
32
8
16


## 3.1. Molecular Phylogeny

We were able to amplify and sequence 470 bp, 645 bp, 935 bp, 775 bp, and 396 bp of the BT2, CAL, RPB, ACT, and SOD loci, respectively. Of the 3221 nucleotides sequenced, 209 (6.5%) were informative for parsimony in the differentScedosporium isolates. For identification, reference sequence ofScedosporium species available in public database were used including BT2 and CAL, but no sequences for RPB, SOD, and ACT were available. The sequences for BT2, CAL, RPB, SOD, and ACT yielded phylogenetic trees with the same topology (Figures 1–5). In the combination phylogenetic trees based on BT2 and CAL (Figure 6), 23 strains in our study were reidentified to the species level according to the reference strains, which were analyzed in the Gilgado literature.P. boydii (9/23) and its closely related subtypesP. ellipsoidea (6/23),P. fusoidea (1/23), andP. angusta (1/23) were the most common, and the other 6 of 23 strains were identified asS. apiospermum.Figure 1
Maximum likelihood tree based on BT2 sequences. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.Figure 2
Maximum likelihood tree based on CAL sequences. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.Figure 3
Maximum likelihood tree based on RPB. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.Figure 4
Maximum likelihood tree based on SOD sequences. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.Figure 5
Maximum likelihood tree based on ACT sequences. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.Figure 6
Maximum likelihood tree based on the analysis produced from the combined BT2 and CAL data. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.The topology of the combined tree (Figure7) of all five loci was similar to those observed in the trees of individual locus and the combined tree of BT2 and CAL. Four principal clades were obtained. The four clades were theP. boydii clade,P. ellipsoidea clade,P. fusoidea/P. angusta clade, andS. apiospermum clade.P. fusoidea andP. angusta always assemble together, andP. boydii andP. ellipsoidea were very closely related.S. apiospermum has the highest intraspecies variability (genetic distance = 0.008), which is comparable to the interspecies variability betweenP. fusoidea andP. angusta (genetic distance = 0.008).Figure 7
Maximum likelihood tree based on the analysis produced from the combined all five markers data. Bootstrap values of >50% are indicated ion branches. The bar indicates the number of substitutions per site.


## 3.2.In Vitro Susceptibility Test

The MIC values for the four antifungal agents examined by the CLSI M-38A2 microdilution method against the 23 strains are presented in Table2. VOR was the most active agent against all 23 strains with a MIC range from 0.25 to 1 μg/mL and a 0.46 μg/mL GM. POS was the second most active agent with MIC values of 2 or 4 μg/mL. For ITR, the intraspecific diversity was obvious as most strains had a MIC between 2 and 4 μg/mL, but five strains were higher at a MIC of 32 μg/mL. AMB is the least effective with high MIC values ranging from 4 to 32 μg/mLin vitro.Table 2
In vitro susceptibility of 23 Scedosporium strains studied in this paper.
Strain species
Strain ID number
MIC (μg/mL)
VOR
POS
ITR
AMB
P. boydii
BMU 00488
0.25
2
4
4
BMU 01112
0.25
2
2
32
BMU 01113
0.25
4
4
32
BMU 01114
0.5
2
4
8
BMU 01116
0.5
2
4
4
BMU 01272
0.5
2
2
8
BMU 02948
0.5
2
2
4
BMU 07224
0.25
2
4
16
BMU 07374
0.25
2
4
4
P. ellipsoidea
BMU 01118
1
4
32
4
BMU 04730
0.5
2
2
4
BMU 04772
0.5
4
32
32
BMU 04780
0.5
4
4
16
BMU 05145
0.5
4
32
8
BMU 07108
0.25
4
4
8
P. angusta
BMU 01115
0.5
2
4
8
P. fusoidea
BMU 01297
0.5
2
2
32
S. apiospermum
BMU 00491
0.5
4
4
4
BMU 01117
0.5
4
4
8
BMU 03882
0.5
2
4
8
BMU 04111
1
4
32
16
BMU 04729
0.5
2
2
8
BMU 07462
1
2
32
8The MIC50 and MIC90 for the four antifungal agents againstP. boydii,P. ellipsoidea, andS. apiospermum are presented in Table 3. There were similar MIC50 and MIC90 for VOR, POS, or AMB of the three species above. For ITR, the MIC90 ofP. boydii (4 μg/mL) was lower than that ofP. ellipsoidea (32 μg/mL) andS. apiospermum (32 μg/mL).Table 3
The MIC50 and MIC90 for the four antifungal agents against P. boydii, P. ellipsoidea, and S. apiospermum.
Species  (number of isolates)
Drug concentration (μg/mL)
VOR
POS
ITR
AMB
MIC50
MIC90
MIC50
MIC90
MIC50
MIC90
MIC50
MIC90
P. boydii(9)
0.25
0.5
2
4
4
4
8
32
P. ellipsoidea (6)
0.5
1
4
4
4
32
8
32
S. apiospermum (6)
0.5
1
2
4
4
32
8
16


## 4. Discussions and Literature Review

Scedosporiosis is a rare infection in China. Sporadic cases ofScedosporium infection have been reported since 1990, but most cases were identified in recent years. We reviewed 39 cases reported in China from 1990 to 2013 [16–31]. We found that infection in the nasal sinuses (16 cases) was the most frequently involved location, followed by eye (13), CNS (5), lung (4), skin/soft tissues (2), arthritis or osteomyelitis (1), and disseminated infection (1). The risk factors included trauma, drowning, and a compromised immune system (bone marrow transplant or stem cell transplantation). Trauma is the most common risk factor for scedosporiosis in Chinese patients, as nearly half of these patients have trauma history. Because cystic fibrosis is extremely rare in the Chinese population, no scedosporiosis in CF was reported in China.Based on molecular identification, we found thatP. boydii complex andS. apiospermum were the only two species in our study. Actually,P. boydii andS. apiospermum demonstrated a closely phylogenetic relationship. This is also reflected by their undifferentiated morphological characteristics, assimilation of different sugars, and growth temperature (data not shown). InP. boydii complex, four closely related subgroups,P. boydii (9 strains),P. ellipsoidea (6 strains),P. fusoidea (1 strain), andP. angusta (1 strain), were present in the study.In a set of clinical and environmental strains from Austria, Germany, and Netherlands,S. apiospermum was the most prevalent, followed byP. boydii [32, 33]. In Australia,S. apiospermum andS. aurantiacum were theScedosporium species with a high incidence except forL. prolificans [4]. Based on our study, we found that in China theP. boydii complex represents the most prevalent species (16/21) followed byS. apiospermum (5/21), which is the same as in Northern Spain and France [34, 35]. In the Chinese strains, we could not findS. aurantiacum, which had a high incidence in Australia and a relatively low incidence in Europe.Antifungal susceptibility profiles for clinical breakpoint ofScedosporium species are still under study. Of the four antifungal tested in this study, VOR was found to be the most active agent againstScedosporium species; POS was the second, and AMB had limited antifungal activity. For ITR, the intraspecific diversity was obvious as the range of MIC from 2 to 32 μg/mL andP. boydii had a lower MIC90 than that ofP. ellipsoidea andS. apiospermum. Thisin vitro susceptibility data is consistent with previous reports [32, 34, 36–38]. In China, most cases caused byScedosporium were treated with either ITR or VOR. AlthoughScedosporium strains have relatively high MIC values for ITR (GM = 5.25)in vitro, studies have verified that they are clinically effective [7].


## 5. Conclusion

TheP. boydii complex andS. apiospermum were the mainScedosporium species in clinical samples in China.Scedosporium species can be distinguished unambiguously by all the five loci in this study. VOR is the most active agentin vitro against the set ofScedosporium species in this study, followed by POS and ITR.



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*Source: 109656-2015-10-07.xml*