Aspergillus welwitschiae; an otomycosis predominant agent, new epidemiological and antifungal susceptibility data from Iran.

BACKGROUND: Black aspergilli (section Nigri) are predominate etiologic agents of otomycosis, however, there is controversy in the exact differentiation of species. For several decades Aspergillus niger is considered the main otomycosis etiologic agent. Recently calmodulin gene has been accepted as a more suitable gene for the accurate assignment of Aspergillus species. Therefore, it is found that A. welwitschiae and A. tubingensis are the main otomycosis agents based on calmodulin gene sequencing. AIMS: The objective of the study was to isolate and identify black aspergilli from otomycosis using the calmodulin gene and their susceptibility was evaluated against several antifungals. METHODS: 134 clinically confirmed patients with otomycosis were sampled and specimens were cultured on Sabouraud dextrose agar (SDA) at ambient temperature. Black aspergilli were screened based on colony morphology on SDA and microscopy features and then subjected to sequencing using calmodulin primers. Moreover, antifungal susceptibility for isolates was applied based on CLSI M38 3rd edition. RESULTS: 132 (98.5%) of patients had positive cultures for different species of molds or yeasts. Most of the patients (30.3%) ranged from 31 to 40 years, and 56.1% of them were female. Aspergillus section Nigri was the most prevalent fungal pathogen and of 86 isolates, 60.5% isolates were identified as A. welwitschiae, A. tubingensis, 31 (36.0%), A. niger (sensu stricto), 2 (2.3%), and A. neoniger 1 (1.2%). According to the maximum likelihood method, all isolates of A. tubingensis and one isolate of A. neoniger were included in the A. tubingensis clade. On the other hand, the clade of A. niger/A. welwitschiae contains, all isolates of A. welwitschiae, two A. niger (sensu stricto) isolates, and 36 isolates from other countries. Aspergillus welwitschiae was more sensitive to luliconazole, voriconazole, and amphotericin B compared to A. tubingensis. 78.8% of A. welwitschiae strains were classified as non-wild type to nystatin compared to 35.5% of A. tubingensis. Moreover, 3.2% of A. tubingensis strains were non-wild type against amphotericin B. The isolates of A. tubingensis were more sensitive to itraconazole than A. welwitschiae. CONCLUSIONS: It is concluded that in contrast, to the previous study A. welwitschiae from section Nigri is the most causative agent of otomycosis followed by A. tubingensis. In addition, the isolates of A. welwitschiae were more sensitive to luliconazole, voriconazole, and amphotericin B compared to A. tubingensis. Whereas, the isolates of A. tubingensis were more sensitive to itraconazole than A. welwitschiae. On the other hand, 78.8% and 35.5% of A. welwitschiae and A. tubingensis strains were classified as a non-wild type against nystatin. Also, 3.2% of A. tubingensis strains were non-wild type against amphotericin B. All A. welwitschiae were included in the A. niger/A. welwitschiae clade, associated with different clinical and environmental species from different countries.

Antifungal susceptibility profiles of otomycosis etiological agents in Ahvaz, Iran.

BACKGROUND AND PURPOSE: Otomycosis is a secondary ear fungal infection among predisposed individuals in humid conditions. Aspergillus species are the most common etiologic agents of this infection. Several ototopical antifungals are currently used for the treatment of this disease; however, recurrence and treatment failure are usually observed in some cases. Regarding this, the present study was conducted to investigate the antifungal activity of caspofungin, azoles, and terbinafine against the isolated agents of otomycosis. MATERIALS AND METHODS: This study was conducted on the specimens collected from 90 patients with otomycosis. The samples were cultured on Sabouraud dextrose agar and identified based on morphological characteristics, physiological tests, and microscopic features. Furthermore, the microdilution method was used for antifungal susceptibility testing according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Finally, the minimum inhibitory concentration (MIC) and minimum effective concentration (MEC) ranges, MIC/MEC50, MIC/MEC90, and geometric mean (GM) MIC/MEC were calculated for the isolates. RESULTS: According to the results, 77 patients with otomycosis were positive for different Aspergillus (88.3%) and Candida (11.7%) species. Aspergillus niger complex (n=36) was found to be the most common agent, followed by A. flavus, A. terreus, and A. nidulans complexes. Furthermore, epidemiological cutoff values (ECVs) were lower than those presented by the CLSI for itraconazole and caspofungin in 98.5% and 42.6% of Aspergillus species, respectively. Terbinafine exhibited a great activity against Aspergillus species, while fluconazole revealed a low activity against both Aspergillus species. Based on the results, 77.8% of Candida species were resistant to caspofungin; however, miconazole and econazole had low MIC ranges. CONCLUSION: Aspergillus niger and A. flavus complexes were identified as the most common agents accounting for 85.7% of the isolates. In addition, terbinafine was identified as the best antifungal for both Aspergillus and Candida species. Moreover, tested azoles had relatively low MICs, whereas most of the isolates had the MIC values beyond the caspofungin ECVs.

The potency of luliconazole against clinical and environmental Aspergillus nigri complex.

BACKGROUND AND OBJECTIVES: Black Aspergillus strains including, Aspergillus niger and A. tubingensis, are the most cause of otomycosis with worldwide distribution. Although, amphotericin B was a Gold standard for the treatment of invasive fungal infection for several decades, it gradually replaced by fluconazole and /or voriconazole. Moreover, luliconazole, appears to offer the best potential for in vitro activity against black Aspergillus strains. The aim of the present study was to compare the in vitro activity luliconazole, with commonly used antifungals against clinical and environmental strains of black Aspergillus. MATERIALS AND METHODS: Sixty seven (37 clinical and 30 environmental) strains of black Aspergillus were identified using morphological and molecular technique (ß-Tubulin gene). In addition, antifungal susceptibility test was applied according to CLSI M38 A2. The results were reported as minimum inhibitory concentration (MIC) or minimum effective concentration (MEC) range, MIC50 or MEC50, MIC90 or MEC90 and MIC geometric (GM) or MECGM. RESULTS: Aspergillus niger was the common isolate followed by, A. tubingensis in both clinical and environmental strains. The lowest MIC range, MIC50, MIC90, and MICGM was attributed to luliconazole in clinical strains. The highest resistant rate was found in amphotericin B for both clinical (86.5%) and environmental (96.7%) strains whereas 54.1% of clinical and 30% of environmental isolates were resistant to caspofungin. Clinical strains of Aspergillus were more sensitive to voriconazole (86.7%) than environmental strains (70.3%). On the other hand, 83.8% of clinical and 70% of environmental isolates were resistant to posaconazole. CONCLUSION: Luliconazole versus amphotericin B, voriconazole, posaconazole and caspofungin is a potent antifungal for Aspergillus Nigri complex. The in vitro extremely antifungal efficacy against black Aspergillus strains of luliconazole, is different from those of other used antifungals.

Candiduria; a review article with specific data from Iran.

Although, several categories of nosocomial infections are presented during the recent years, urinary tract infections (UTIs) considered as one of the most important systemic infections. The presence of Candida species in the urinary tract system (Candiduria) is seen in only 10-15% of the cases with UTI, however candiduria has been considered as more problematic infection for patients, laboratory workers and physicians. Due to increasing numbers of several predisposing factors, such as antibacterial agents, urinary tract instrumentation, diabetes mellitus, invasive therapies, and prolonged hospital stay, candiduria develops among the hospitalized patients, especially hospitalized in intensive care units (ICUs) and neonatal intensive care units (NICUs). According to the epidemiological studies, Candida albicans is the most common isolated species from candiduric patients. However, during the recent years, due to increasing resistance to antifungal drugs, non-albicans Candida species including, C. glabrata, C. krusei, C. parapsilosis and C. tropicalis have been also implicated. We found that the mean prevalence of candiduria among Iranian patients was lower (16.5%) than worldwide ratio and also males were more frequently affected than females (M:F, 1.2:1). Similar to other countries, C. albicans was most common infectious agent followed by non-albicans Candida species including, C. glabrata, C. tropicalis and C. krusei.