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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 25  |  Issue : 2  |  Page : 76-77

Fungi in the normal human external ear


1 Department of Otorhinolaryngology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
2 Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia

Date of Web Publication16-Aug-2019

Correspondence Address:
Dr. Raudha Ezaty Ruslan
Department of Otorhinolaryngology, Faculty of Medicine, University of Malaya, Kuala Lumpur
Malaysia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/indianjotol.INDIANJOTOL_90_18

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  Abstract 


Aim: The aim of this study is to determine the presence of fungi in the human external ear. Materials and Methods: A total of 84 specimens of skin scraping were taken from the external ear canals of 46 randomly selected adult ears with their consent. Patients were 15 males and 31 females, with a mean age of 51 years (22 years to 86 years). Of these, 38 patients were from both the ears, and 4 each from right or left ear, respectively, making it a total of 84. These samples were sent to the microbiology laboratory for potassium hydroxide staining for fungal elements and then cultured in sabouraud dextrose agar with olive oil. If fungus was detected on the agar after 2–4 weeks of incubation, the type of fungus was read and verified by a microbiologist. Results: Forty specimens were positive (47.6%) and 44 were negative for fungal culture. The positive culture was Malassezia furfur in 31 (77.5%) and other fungi (Candida albicans 1, Candida parapsilosis 6 and Aspergillus species 2) in 9 (22.5%). Conclusion: There are fungi as commensals in the external human ear, M. Furfur is the most common fungus.

Keywords: External ear, fungi, malassezia furfur


How to cite this article:
Ruslan RE, Rajagopalan R, Ng KP. Fungi in the normal human external ear. Indian J Otol 2019;25:76-7

How to cite this URL:
Ruslan RE, Rajagopalan R, Ng KP. Fungi in the normal human external ear. Indian J Otol [serial online] 2019 [cited 2019 Sep 21];25:76-7. Available from: http://www.indianjotol.org/text.asp?2019/25/2/76/264677




  Introduction Top


Malassezia is a fungus species common to the normal human cutaneous flora. It is usually found on human skin and can be isolated from the sebaceous-rich area of the skin, particularly the head and upper trunk.[1]

Human ears have been studied to show the presence of Malassezia,[2] Candida is also mentioned in the normal human ear.[2]


  Materials and Methods Top


Participants recruited for this study were patients presented to the ENT clinic during 6 months. A total of 84 specimens of skin scraping were taken from the external ear canals of 46 consenting adult participants. Of these, 38 participants were from both the ears and 4 each from the right or left ear, respectively, making it a total of 84. Ethical clearance was obtained from the university medical center. Of these participants, 25 (54.35%) were Malays, 10 (21.74%) were Chinese, 8 (17.4%) were Indians, and 6.5% others. Gender distribution was 15 (32.6%) males, and 31 (67.4%) females. Mean age was 51 years (22 years – 80 years) (SD18.32). Then, the ears were examined under the microscope and only clinically normal ears were included in the study.

The skin scraping specimens were taken from the external ear canal (outer 2/3) using Jobson-Horne curette. Care was taken to avoid any trauma to the ear canal and not to extend the specimen collection beyond the bony-cartilaginous junction.

The skin scraping was mounted on a dry glass slide cover and transported in a universal container. Samples were sent to the microbiology laboratory for KOH (potassium hydroxide) staining for fungal elements and then cultured in Sabouraud Dextrose Agar with olive oil. It was incubated at 25°C–30°C. If fungus was detected on the agar after 2–4 weeks of incubation, the type of fungus was read and verified by a microbiologist.


  Results Top


This study involved 46 patients (15 [32.6%] males and 31 [67.4%] females) with a mean age of 51 years (ranging from 22 to 86 years) and standard deviation of 18.32.

There was no correlation between the age, gender, and race to the positive fungal culture.

A total of 84 ears were examined for the presence of the fungus. Forty were positive and 44 were negative for fungal culture. There were no other symptoms in the fungus positive groups. Although some complained of itchiness of the ear, there is no association between fungal culture and ear itchiness.

The 40 positive cultures were further analyzed and Malassezia furfur was identified in 31 (77.5%) and other fungus (Candida albicans 1, Candida parapsilosis 6 and Aspergillus species 2) were identified in 9 (22.5%) of the cultures. M. Furfur remains the most common commensals.


  Discussion Top


Malassezia species is a fungus that is most commonly associated with seborrheic dermatitis and dandruff.

This study involved 46 patients with a mean age of 51. There was no significant difference in positive fungal culture between the two age groups >50 and <50. Similarly, there was no correlation between races and gender.

This is slightly different from a previous study that showed the highest incidence of Malassezia species is in the EAC of healthy adults over 30 years of age and it is more in males compared to females, although the difference was not statistically significant.[2]

Most of the studies investigated Malassezia in the asymptomatic normal human ear.[2] There are other studies involving normal human ears, namely, Malassezia in the ears,[3] 310 ears fungal isolates were 2.5% with candida paraspilosis and penicillium species.[4] About 10.25% in 243 normals with penicillium mostly and other species.[5] In comparison, our study shows it to be 47.6%. This high prevalence may be because this is a tropical country with high humidity and heat.

Other animal studies compared the presence of Malassezia in both normal and diseased ears.[6],[7]

Under the influence of factors such as high temperature and humidity, greasy skin, sweating and immunosuppressive therapy, the yeast phase of Malassezia transformed into the mycelial phase, therefore, they are also known as opportunistic pathogens.[8]


  Conclusion Top


There are fungi present as normal commensals in the external ear. The present study shows up to 47.6%. M. Furfur is the most common fungus seen. This high incidence may be due to high humidity and heat in a tropical country. These fungi might convert into an opportunistic pathogen under certain conditions, namely, host factor, trauma, and environmental factors.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Leeming JP, Notman FH, Holland KT. The distribution and ecology of Malassezia furfur and cutaneous bacteria on human skin. J Appl Bacteriol 1989;67:47-52.  Back to cited text no. 1
    
2.
Kaneko T, Shiota R, Shibuya S, Watanabe S, Umeda Y, Takeshita K, et al. Human external ear canal as the specific reservoir of Malassezia slooffiae. Med Mycol 2010;48:824-7.  Back to cited text no. 2
    
3.
Dibb WL. The normal microbial flora of the outer ear canal in healthy Norwegian individuals. NIPH Ann 1990;13:11-6.  Back to cited text no. 3
    
4.
Stroman DW, Roland PS, Dohar J, Burt W. Microbiology of normal external auditory canal. Laryngoscope 2001;111:2054-9.  Back to cited text no. 4
    
5.
Pakshir K, Sabayan B, Javan H, Karamifar K. Mycoflora of human external auditory canal in Shi-Raz, Southern Iran. Iran Red Crescent Med J 2008;10:27.  Back to cited text no. 5
    
6.
Girão MD, Prado MR, Brilhante RS, Cordeiro RA, Monteiro AJ, Sidrim JJ, et al. Malassezia pachydermatis isolated from normal and diseased external ear canals in dogs: A comparative analysis. Vet J 2006;172:544-8.  Back to cited text no. 6
    
7.
Cafarchia C, Gallo S, Capelli G, Otranto D. Occurrence and population size of Malassezia spp. In the external ear canal of dogs and cats both healthy and with otitis. Mycopathologia 2005;160:143-9.  Back to cited text no. 7
    
8.
Ljubojević S, Skerlev M, Lipozencić J, Basta-Juzbasić A. The role of Malassezia furfur in dermatology. Clin Dermatol 2002;20:179-82.  Back to cited text no. 8
    




 

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Abstract
Introduction
Materials and Me...
Results
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