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Microbiology and antimicrobial susceptibility of otitis externa: a changing pattern of antimicrobial resistance

  • E Heward (a1), M Cullen (a2) and J Hobson (a1)



Otitis externa is a common presentation to secondary care otolaryngology clinics. Despite this, few studies have investigated the microbiology and antimicrobial resistance of otitis externa. This study aimed to examine these issues.


Analysis identified 302 swabs taken from 217 patients (100 male, 117 female), between 1 January 2015 and 30 March 2016, at our rapid access otolaryngology clinic.


In total, 315 organisms were isolated; the most frequent was Pseudomonas aeruginosa (31.1 per cent), followed by candida species (22.9 per cent) and Staphylococcus aureus (11.7 per cent). P aeruginosa was sensitive to ciprofloxacin in 97.7 per cent of cases and to gentamicin in 78.4 per cent.


Compared with studies worldwide, the relative proportions of different organisms causing otitis externa and the patterns of antimicrobial resistance differ. Increasing resistance of P aeruginosa to aminoglycosides demonstrates a changing pattern of antimicrobial resistance that has not been previously reported. Reassuringly, quinolone antibiotics remain highly effective when treating P aeruginosa.


Corresponding author

Address for correspondence: Mr Elliot Heward, Department of Otolaryngology, University Hospital of South Manchester NHS Foundation Trust, Manchester, UK E-mail:


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Presented orally at the International Federation of ORL Societies (‘IFOS’) World ENT Congress, 26 June 2017, Paris, France.



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1Rowlands, S, Devalia, H, Smith, C, Hubbard, R, Dean, A. Otitis externa in UK general practice: a survey using the UK General Practice Research Database. Br J Gen Pract 2001;51:533–8
2Guthrie, RM. Diagnosis and treatment of acute otitis externa. An interdisciplinary update. Ann Otol Rhinol Laryngol Suppl 1999;176:123
3Ninkovic, G, Dullo, V, Saunders, NC. Microbiology of otitis externa in the secondary care in United Kingdom and antimicrobial sensitivity. Auris Nasus Larynx 2008;35:480–4
4Walshe, P, Rowley, H, Timon, C. A worrying development in the microbiology of otitis externa. Clin Otolaryngol Allied Sci 2001;26:218–20
5Hannley, MT, Denneny, JC 3rd, Holzer, SS. Use of ototopical antibiotics in treating 3 common ear diseases. Otolaryngol Head Neck Surg 2000;122:934–40
6Davies, J, Davies, D. Origins and evolution of antibiotic resistance. Microbiol Mol Biol Rev 2010;74:417–33
7Jayakar, R, Sanders, J, Jones, E. A study of acute otitis externa at Wellington Hospital, 2007–2011. Australas Med J 2014;7:392–9
8Enoz, M, Sevinc, I, Lapeña, JF. Bacterial and fungal organisms in otitis externa patients without fungal infection risk factors in Erzurum, Turkey. Braz J Otorhinolaryngol 2009;75:721–5
9Roland, PS, Stroman, DW. Microbiology of acute otitis externa. Laryngoscope 2002;112:1166–77
10Amigot, SL, Gomez, CR, Luque, AG, Ebner, G. Microbiological study of external otitis in Rosario City, Argentina. Mycoses 2003;46:312–15
11Dibb, WL. Microbial aetiology of otitis externa. J Infect 1991;22:233–9
12Kiakojuri, K, Omran, SM, Jalili, B, Hajiahmadi, M, Bagheri, M, Shahandashti, EF et al. Bacterial otitis externa in patients attending an ENT clinic in Babol, North of Iran. Jundishapur J Microbiol 2016;9:e23093
13Rosenfeld, RM, Singer, M, Wasserman, JM, Stinnett, SS. Systematic review of topical antimicrobial therapy for acute otitis externa. Otolaryngol Head Neck Surg 2006;134:S2448
14Mösges, R, Nematian-Samani, M, Hellmich, M, Shah-Hosseini, K. A meta-analysis of the efficacy of quinolone containing otics in comparison to antibiotic–steroid combination drugs in the local treatment of otitis externa. Curr Med Res Opin 2011;27:2053–60
15Phillips, JS, Yung, MW, Burton, MJ, Swan, IR. Evidence review and ENT-UK consensus report for the use of aminoglycoside-containing ear drops in the presence of an open middle ear. Clin Otolaryngol 2007;32:330–6
16Rosenfeld, RM, Schwartz, SR, Cannon, CR, Roland, PS, Simon, GR, Kumar, KA et al. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg 2014;150:S124
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The Journal of Laryngology & Otology
  • ISSN: 0022-2151
  • EISSN: 1748-5460
  • URL: /core/journals/journal-of-laryngology-and-otology
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