Species identification and in vitro antifungal susceptibility testing of Aspergillus section Nigri strains isolated from otomycosis patients

Sarwestani, Zahra Kamali; Hashemi, Seyed Hossein; Rezaie, Sasan; Shoar, Mohsen Gerami; Mahmoudi, Shahram; Elahi, M Sheykh Fath; Bahardoost, Mansoor; Tajdini, Ardavan; Abutalebian, S.; Ghazvini, Roshanak Daie

doi:10.1016/j.mycmed.2018.02.003

Cited by 23 publications

(10 citation statements)

References 31 publications

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“…Isolates were selected in chronological order by each center, so there is no bias according to clinical implication. As previously reported by others (12,13), our results indicate that A. tubingensis is far more frequently isolated than A. niger. Therefore, our study reinforces that, in contrast to other parts of the world (8, 14), A. niger seems to be uncommon in Europe.…”

Section: Discussionsupporting

confidence: 90%

Species Distribution and Comparison between EUCAST and Gradient Concentration Strips Methods for Antifungal Susceptibility Testing of 112 Aspergillus Section Nigri Isolates

Carrara

Richards

Imbert

et al. 2020

Antimicrob Agents Chemother

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Aspergillus niger, the third species responsible for invasive aspergillosis, has been considered as a homogeneous species until DNA-based identification uncovered many cryptic species. These species have been recently reclassified into the Aspergillus section Nigri. However, little is yet known among the section Nigri about the species distribution and the antifungal susceptibility pattern of each cryptic species. A total of 112 clinical isolates collected from 5 teaching hospitals in France and phenotypically identified as A. niger were analyzed. Identification to the species level was carried out by nucleotide sequence analysis. The MICs of itraconazole, voriconazole, posaconazole, isavuconazole, and amphotericin B were determined by both the EUCAST and gradient concentration strip methods. Aspergillus tubingensis (n = 51, 45.5%) and Aspergillus welwitschiae (n = 50, 44.6%) were the most common species while A. niger accounted for only 6.3% (n = 7). The MICs of azole drugs were higher for A. tubingensis than for A. welwitschiae. The MIC of amphotericin B was 2 mg/liter or less for all isolates. Importantly, MICs determined by EUCAST showed no correlation with those determined by the gradient concentration strip method, with the latter being lower than the former (Spearman’s rank correlation tests ranging from 0.01 to 0.25 depending on the antifungal agent; P > 0.4). In conclusion, A. niger should be considered as a minority species in the section Nigri. The differences in MICs between species for different azoles underline the importance of accurate identification. Significant divergences in the determination of MIC between EUCAST and the gradient concentration strip methods require further investigation.

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Section: Discussionsupporting

confidence: 90%

Species Distribution and Comparison between EUCAST and Gradient Concentration Strips Methods for Antifungal Susceptibility Testing of 112 Aspergillus Section Nigri Isolates

Carrara

Richards

Imbert

et al. 2020

Antimicrob Agents Chemother

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“…Regarding the mold isolates, DNA was extracted by the phenol-chloroform method [19], and a fragment of ITS rDNA or beta-tubulin gene, depending on the genus of the isolate, was PCR-amplified and sent for sequencing as described previously [20,21]. Definitive identification of isolates was accomplished by the BLAST analysis (https://blast.ncbi.nlm.nih.gov/Blast.…”

Section: Identification Of Isolated Fungimentioning

confidence: 99%

Molecular characterization of fungi causing colonization and infection in organ transplant recipients: a one-year prospective study

Zarei¹,

Hashemi²,

Salehi³

et al. 2020

CMM

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Background and Purpose: Organ transplant recipients are vulnerable to fungal infections. The aim of this study was to determine the prevalence of fungal colonization and infections among patients who underwent various transplantations and molecularly characterize the etiological agents. Materials and Methods: This study was conducted on candidates for transplantation in Imam Khomeini Hospital, Tehran, Iran, from April 2017 to April 2018. All patients were monitored for fungal colonization or infections before and after transplantation. Isolated fungi were identified using molecular methods. Results: A total of 125 patients, including 86 males and 39 females, with the mean age of 52.2 years participated in the study (age range: 15-75 years). Out of 125 patients, 84 (67.2%) cases had fungal colonization that appeared pre- and post-transplantation in 21 and 63 cases, respectively (alone or concurrent with another infection in 55 and 29 cases, respectively). In addition, a total of 39 episodes of fungal infections were diagnosed in 36 (28.8%) recipients (alone or concurrent with colonization in 7 and 29 cases, respectively). Out of the 39 fungal infections, 9 cases appeared pre-transplantation, while the other 30 cases occurred post-transplantation. However, no fungal colonization or infection was observed in 34 (27.2%) patients. Oral candidiasis (n=20) was the most common type of infection, followed by funguria (n=7), onychomycosis (n=5), candidemia (n=3), rhinocerebral mucormycosis (n=1), cutaneous mucormycosis (n=1), cutaneous aspergillosis (n=1), and peritonitis (n=1). Six yeast species were recovered from colonization cases with the dominance of Candida albicans both before and after transplantation. The observed fungal infections were caused by 11 distinct species, including the members of Candida (i.e., C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei), Aspergillus (i.e., A. oryzae and A. candidus), Rhizopus (i.e., R. oryzae and R. microsporus), Trichosporon asahii, and Trichophyton interdigitale. The results also indicated that the development of a fungal infection post-transplantation was associated with fungal colonization (r=0.0184; P=0.043). Conclusion: Based on the results, fungal colonization was a common finding in transplant recipients at Imam Khomeini Hospital. However, the incidence of fungal infections was comparable with those of other centers. As the oral cavity was the most common site of colonization and infection, it might be beneficial to take further care about the oral health of patients using effective mouthwash.

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“…Pseudomonas aeruginosa and Staphylococcus aureus are frequently listed as the most predominant agents causing an acute form of OE (Schaefer and Baugh, 2012). On the other hand, fungal agents, most commonly Aspergillus and Candida species, are associated with prolonged antibiotic usage and chronic OE (Sarwestani et al, 2018;Aboutalebian et al, 2019;Punia et al, 2019). Complaints of acute onset of unilateral ear pain, itching, and a sense of aural fullness are the typical manifestations of acute otitis externa caused by bacteria.…”

Section: Introductionmentioning

confidence: 99%

Direct Detection and Identification of the Most Common Bacteria and Fungi Causing Otitis Externa by a Stepwise Multiplex PCR

Aboutalebian

Ahmadikia

Fakhim

et al. 2021

Front. Cell. Infect. Microbiol.

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BackgroundConsidering the importance of differential diagnosis of infectious otitis externa (OE), a stepwise PCR-based assay using universal and genus- or species-specific primers for the detection/identification of the most prevalent bacterial and fungal OE was developed and evaluated on the ear aspiration specimens of clinically suspected patients.Methods and MaterialsA total of 120 ear aspiration specimens with otomycosis suspicion were subjected to manual DNA extraction using phenol–chloroform extraction after tissue digestion with a lysis buffer. The multiplex PCR was initially performed using pan-fungal and bacterial homemade primers. Pseudomonas and Staphylococcus specific primers were simultaneously used in one reaction mixture to identify the bacterial genera. Furthermore, for the identification of fungal agents, Candida species-specific multiplex primers targeting the most clinically important Candida species causing OE (i.e., C. albicans, C. parapsilosis, and C. auris), as well as Aspergillus related multiplex PCR identifying the most prevalent Aspergillus species were used in two separate reaction mixtures. All the results of multiplex PCR were interpreted based on the amplicon size.ResultsThe overall multiplex PCR-based detection rate of bacterial (n = 88; 73.3%) and fungal (n = 97; 81%) OE was documented to be 100% along with and complete consistency with the results of direct examination and Giemsa staining. Double amplicon bands of bacterial and fungal pathogens were evidenced in 76 specimens (63.3%). Moreover, the positivity rate of pan-fungal PCR was higher than that of the culture result. Out of 88 pan-bacterial positive PCR specimens, 66 and 47 ones were positive for Staphylococcus and Pseudomonas, respectively. In addition, 30 samples exhibited mixed infection of both, and five specimens remained negative. Out of 97 pan-fungal positive PCR specimens, 67 and 51 ones contained Candida and Aspergillus species, respectively. It should be noted that dual amplicon bands of Candida and Aspergillus-related multiplex PCR were yielded in 30 specimens.ConclusionThe stepwise multiplex PCR assay proved to be more sensitive, more rapid, as well as less cumbersome in detection and identification of fungal and bacterial OE, compared to culture.

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Species identification and in vitro antifungal susceptibility testing of Aspergillus section Nigri strains isolated from otomycosis patients

Cited by 23 publications

References 31 publications

Species Distribution and Comparison between EUCAST and Gradient Concentration Strips Methods for Antifungal Susceptibility Testing of 112 Aspergillus Section Nigri Isolates

Species Distribution and Comparison between EUCAST and Gradient Concentration Strips Methods for Antifungal Susceptibility Testing of 112 Aspergillus Section Nigri Isolates

Molecular characterization of fungi causing colonization and infection in organ transplant recipients: a one-year prospective study

Direct Detection and Identification of the Most Common Bacteria and Fungi Causing Otitis Externa by a Stepwise Multiplex PCR

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