Electronic equipment and appliances in special wards of hospitals as a source of azole-resistant Aspergillus fumigatus: a multi-centre study from Iran

BACKGROUND

Azole-resistant Aspergillus fumigatus (ARAf), reported as a global public health concern, has been unexpectedly observed in different countries.

AIM

To identify ARAf and detect azole resistance related to the CYP51A mutation in different hospital environmental samples.

METHODS

In this multi-centre study from Iran, surfaces of electronic equipment and appliances from different hospitals in Iran were sampled using cotton swabs. All samples were cultured using azole-containing agar plates (ACAPs). Recovered Aspergillus isolates were identified at the species level using partial DNA sequencing of the β-tubulin gene. The azole susceptibility testing of A. fumigatus isolates was performed using the Clinical and Laboratory Standards Institute M38-A3 guideline. The sequencing of the CYP51A gene was also performed to detect mutations related to resistance.

FINDINGS

Out of the 693 collected samples, 89 (12.8%) Aspergillus species were recovered from ACAPs. Aspergillus fumigatus (41.6%) was the most prevalent, followed by A. tubingensis (23.6%) and A. niger (15.6%). Among 37 isolates of A. fumigatus, 19 (51.3%) showed high minimum inhibitory concentration (MIC) values to at least one of the three azoles, voriconazole, itraconazole, and posaconazole. CYP51A polymorphisms were detected in all 19 isolates, of which 52.6% showed the TR34/L98H mutation. Other detected mutations were G432C, G448S, G54E/G138C, F46Y, and Y121F/M220I/D255E. T289F and G432C were the first reported mutations in ARAf.

CONCLUSION

There was a considerable level of azole resistance in hospital environmental samples, a serious warning for patients vulnerable to aspergillosis. Our findings have also revealed a different mutation pattern in the CYP51A gene.

Hyphal wall protein 1 gene: A potential marker for the identification of different Candida species and phylogenetic analysis

BACKGROUND AND PURPOSE

Hyphal wall protein 1 (HWP1) is an important adhesin which usually is expressed on the germ tube and hyphal surface produced by different Candida species. The hyphal wall protein-coding gene (HWP1) was evaluated as a novel identification and phylogenetic marker in Candida tropicalis, C. orthopsilosis, C. parapsilosis and C. glabrata.

MATERIALS AND METHODS

Initially, four specific primer pairs were designed, and the target was amplified and finally sequenced. A total of 77 Candida isolates from four different species were included in the study. Consensus sequences were used for the evaluation of phylogenetic tree using the CLC Genome Workbench, GENEIOUS, and MEGA softwares and the levels of nucleotide and amino acid polymorphism were assessed.

RESULTS

According to the results, the specific amplified fragments of HWP1 gene were useful for the differentiation of four species. Intra-species variation was observed only in C. tropicalis with two DNA types. The phylogenetic tree of Candida species based on the HWP1 gene showed consistency in topology with those inferred from other gene sequences.

CONCLUSION

We found that HWP1 gene was an excellent marker for the identification of non-albicansCandida species as well as the phylogenetic analysis of the most clinically significant Candida species.

In vitro activity of econazole in comparison with three common antifungal agents against clinical Candida strains isolated from superficial infections

Background and Purpose:

Candida species are the most common organisms involved in superficial fungal infections, worldwide. Although econazole is among the most frequently used topical formulations for the treatment of candidiasis, no information is available regarding the susceptibility profiles of Candida species in Iran.

Materials and Methods:

In vitro susceptibility of 100 clinical Candida isolates belonging to 6 species from superficial candidiasis of Iran towards to econazole was compared with three other common antifungal agents including itraconazole, fluconazole, and miconazole. Minimum inhibitory concentrations (MICs) values were analyzed according to the Clinical and Laboratory Standards Institute (CLSI) M38-A3 document. All isolates were previously identified to the species level, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on ITS region.

Results:

The MIC of econazole, itraconazole, miconazole, and fluconazole were within the range of 0.016-16, 0.032-16, 0.016-16, and 0.25-64 μg/ml, respectively. In general, econazole and miconazole were more active against Candida isolates, compared to the other two agents.

Conclusion:

The present study demonstrated that for Candida albicans isolates, miconazole and econazole had the best effect, but in non-albicans Candida species, itraconazole and miconazole displayed more activity than other antifungal agents.

Detection of fungi by conventional methods and semi-nested PCR in patients with presumed fungal keratitis

Background and Purpose:

Fungal keratitis is a suppurative, ulcerative, and sight-threatening infection of the cornea that sometimes leads to blindness. The aims of this study were: recuperating facilities for laboratory diagnosis, determining the causative microorganisms, and comparing conventional laboratory diagnostic tools and semi-nested PCR.

Materials and Methods:

Sampling was conducted in patients with suspected fungal keratitis. Two corneal scrapings specimens, one for direct smear and culture and the other for semi- nested PCR were obtained.

Results:

Of the 40 expected cases of mycotic keratitis, calcofluor white staining showed positivity in 25%, culture in 17.5%, KOH in 10%, and semi-nested PCR in 27.5%. The sensitivities of semi-nested PCR, KOH, and CFW were 57.1%, 28.5%, and 42% while the specificities were 78.7%, 94%, and 78.7%, respectively. The time taken for PCR assay was 4 to 8 hours, whereas positive fungal cultures took at least 5 to 7 days.

Conclusion:

Due to the increasing incidence of fungal infections in people with weakened immune systems, uninformed using of topical corticosteroids and improper use of contact lens, fast diagnosis and accurate treatment of keratomycosis seems to be essential. Therefore, according to the current study, molecular methods can detect mycotic keratitis early and correctly leading to appropriate treatment.

First fatal cerebral phaeohyphomycosis due to Rhinocladiella mackenziei in Iran, based on ITS rDNA

Black yeast-like fungi and relatives as agents of cerebral phaeohyphomycosis are often encountered in human fatal brain abscesses and lead to almost 100% mortality despite the application of antifungal and surgical therapy. We report to our knowledge the first case of brain infection due to Rhinocladiella mackenziei in a 54-year-old immunocompetent male in Iran where R. mackenziei has not been reported previously. The initial diagnosis was brain fungal infection because of pigmented, irregular, branched, septated hyphae based on histopathological staining. The patient was treated with intravenous amphotericin B deoxycholate (0.5mg/kg/day) combined with oral itraconazole (200mg twice daily), nevertheless, his neurological function deteriorated rapidly and ultimately the patient died due to respiratory failure later two weeks. R. mackenziei was identified based on the sequencing of internal transcribed spacer (ITS rDNA region) (KJ140287). Therefore, considerable attention for this life-threatening infection is highly recommended.