Original Article

Enzymatic activity of clinical and environmental isolates of Aspergillus flavus section Flavi

Abstract

Background and Objectives: The ability of Aspergillus species to produce various extracellular enzymes has a pathogenic role in humans. These enzymes not only play a role in metabolism but also act as virulence factors. The secretion of hydrolytic enzymes facilitates tissue invasion and is considered a virulence factor for several fungi. The current study aimed to compare the enzymatic activity of A. flavus section Flavi isolated from otomycosis and environmental samples.
Materials and Methods: In the present study, eighty-one isolates of A. flavus including 41 clinical strains from otomycosis and 40 environmental isolates were identified using the calmodulin gene. The enzymatic activity of the isolates was assessed using standard culture media.
Results: All isolates exhibited phospholipase and urease activity. Esterase and hemolysin activity in otomycosis isolates were higher than in environmental isolates (88% > 62%), (98% > 72%). High levels of both extracellular and intracellular catalase activity were detected among otomycosis isolates.
Conclusion: All isolates were phenotypically identified as Aspergillus section Flavi and then characterized using the calmodulin gene. The mean activity of intracellular catalase enzymes (1.29) in both groups was higher than the mean activity of extracellular catalase enzymes (0.85). Additionally, the esterase (88%) and hemolysin (98%) activity of the clinical isolates was higher than that of the environmental isolates (esterase 62%, hemolysin 72%). All isolates exhibited phospholipase and urease activity.

1. Alp S, Arikan S. Investigation of extracellular elastase, acid proteinase and phospholipase activities as putative virulence factors in clinical isolates of Aspergillus species. J Basic Microbiol 2008; 48: 331-337.
2. Balakrishnan Sangeetha A, Abdel-Hadi A, Hassan AS, Shobana CS, Suresh S, Abirami B, et al. Evaluation of in vitro activities of extracellular enzymes from Aspergillus species isolated from corneal ulcer/keratitis. Saudi J Biol Sci 2020; 27: 701-705.
3. Ghorbel D, Hadrich I, Neji S, Trabelsi H, Belaaj H, Sellami H, et al. Detection of virulence factors and antifungal susceptibility of human and avian Aspergillus flavus isolates. J Mycol Med 2019; 29: 292-302.
4. Birinci A, Bilgin K, Tanriverdi Cayci Y. Investigation of acid proteinase and phospholipase activity as virulence factors in clinical Aspergillus spp. isolates. Mikrobiyol Bul 2014; 48: 491-494.
5. Rouein S, Ghasemi F, Badiee P. Compare catalase activity between Aspergillus flavus and A. fumigatus, isolated from clinical and environmental specimens. Jundishapur J Microbiol 2020; 13(8): e103634.
6. Gharaghani M, Jafarian H, Hatami M, Shabanzadeh M, Zarei Mahmoudabadi A. Evaluation of catalase activity of clinical and environmental isolates of Aspergillus species. Iran J Microbiol 2022; 14: 133-137.
7. Raksha, Singh G, Urhekar AD. Virulence factors detection in Aspergillus isolates from clinical and environmental samples. J Clin Diagn Res 2017; 11(7): DC13-DC18.
8. Al-Wathiqi F, Ahmad S, Khan Z. Molecular identification and antifungal susceptibility profile of Aspergillus flavus isolates recovered from clinical specimens in Kuwait. BMC Infect Dis 2013; 13: 126.
9. Pasqualotto AC. Differences in pathogenicity and clinical syndromes due to Aspergillus fumigatus and Aspergillus flavus. Med Mycol 2009; 47 (Suppl 1): S261-S270.
10. Hamzehee S, Gharaghani M, Borsi SH, Jafarian H, Jalaee GA, Kardooni M, et al. The frequency distribution of Aspergillus section Nigri from clinical and environmental samples in Iran. BMC Microbiol 2025; 25: 571.
11. Jafarian H, Hardani AK, Asnafi AA, Mahmoudabadi AZ. Enzymatic and antifungal susceptibility profiles of Candida glabrata isolates from paediatric patients and their genetic diversity based on microsatellite length polymorphism. Lett Appl Microbiol 2022; 75: 1569-1578.
12. Slifkin M. Tween 80 opacity test responses of various Candida species. J Clin Microbiol 2000; 38: 4626-4628.
13. Moharram A, Ahmed H, Nasr S. Otomycosis in Assiut, Egypt. J Basic Appl Mycol (Egypt) 2013; 4: 1-11.
14. Moslem M, Fatahinia M, Kiasat N, Zarei Mahmoudabadi A. Predominance of Cryptococcus neoformans var. grubii in Ahvaz, molecular identification and evaluation of virulence Factors. Jundishapur J Microbiol 2020; 13(11): e112408.
15. Frisvad JC, Hubka V, Ezekiel CN, Hong SB, Novakova A, Chen AJ, et al. Taxonomy of Aspergillus section Flavi and their production of aflatoxins, ochratoxins and other mycotoxins. Stud Mycol 2019; 93: 1-63.
16. Ali K, Hamed MA, Hassan H, Esmail A, Sheneef A. Identification of fungal pathogens in otomycosis and their drug sensitivity: our experience. Int Arch Otorhinolaryngol 2018; 22: 400-403.
17. Gharaghani M, Seifi Z, Zarei Mahmoudabadi A. Otomycosis in Iran: A review. Mycopathologia 2015; 179: 415-424.
18. Xiong Z, Zhang N, Xu L, Deng Z, Limwachiranon J, Guo Y, et al. Urease of Aspergillus fumigatus is required for survival in macrophages and virulence. Microbiol Spectr 2023; 11(2): e0350822.
19. Gharaghani M, Shabanzadeh M, Jafarian H, Zarei Mahmoudabadi A. ABC typing and extracellular enzyme production of Candida albicans isolated from Candida vulvovaginitis. J Clin Lab Anal 2022; 36(1): e24117.
20. Bavadharani S, Premamalini T, Karthika K, Kindo AJ. In vitro production of virulence factors and antifungal susceptibility pattern of Aspergillus isolates from clinical samples in a tertiary care center. J Lab Physicians 2022; 14: 479-484.
21. Fatahinia M, Poormohamadi F, Zarei Mahmoudabadi A. Comparative study of esterase and hemolytic activities in clinically important Candida species, isolated from oral cavity of diabetic and non-diabetic individuals. Jundishapur J Microbiol 2015; 8(3): e20893.
22. Jafarian H, Hardani AK, Asnafi AA, Mahmoudabadi AZ. Population structure, susceptibility profile, phenotypic and mating properties of Candida tropicalis isolated from pediatric patients. Microb Pathog 2022; 170: 105690.
23. Itor EA, Noubom M, Nangwat C, Ngueguim DA, Kountchou CL, Thierry NK, et al. Invasive factors recognition in Aspergillus section Nigri isolates from patient and environmental samples in the centre Region, Cameroon. Asian J Res Infect Dis 2020; 5: 1-8.
24. Roman E, Prieto D, Martin R, Correia I, Mesa Arango AC, Alonso-Monge R, et al. Role of catalase overproduction in drug resistance and virulence in Candida albicans. Future Microbiol 2016; 11: 1279-1297.
25. Yun Y, Lu Z, Yang J, Liang T, Xiao G, Qiao Y, et al. Electrochemical analysis of specific catalase activity during development of Aspergillus flavus and its correlation with aflatoxin B1 production. Food Chem 2021; 337: 127978.
26. Koleva Z, Abrashev R, Angelova M, Stoyancheva G, Spassova B, Yovchevska L, et al. A novel extracellular catalase produced by the antarctic filamentous fungus Penicillium rubens III11-2. Fermentation 2024; 10: 58.
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IssueVol 18 No 4 (2026) QRcode
SectionOriginal Article(s)
Keywords
Aspergillus flavus Otomycosis Extracellular enzymes Pathogenicity
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How to Cite
1.
Halvaeezadeh M, Jalaee GA, Fatahinia M, Zarei Mahmoudabadi A. Enzymatic activity of clinical and environmental isolates of Aspergillus flavus section Flavi. Iran J Microbiol. 2026;18(4):621-628.