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Year : 2016  |  Volume : 22  |  Issue : 3  |  Page : 157-161

Current bacteriological profile of chronic suppurative otitis media in a tertiary facility of Northern Nigeria

1 Department of ENT, Federal Medical Centre, Birnin Kudu, Jigawa State, Nigeria
2 Department of Biological Science, Bayero University, Kano, Nigeria

Date of Web Publication8-Aug-2016

Correspondence Address:
Dr. Mohammed Jamiu Kazeem
Department of ENT, Federal Medical Centre, Birnin Kudu, Jigawa State
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-7749.187979

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Aims: The aim of the study was to re-evaluate the current bacteriological profile of chronic suppurative otitis media (CSOM) and the sensitivity pattern to most of the currently available antibiotics in our environment. Settings and Design: This is a hospital-based, correctional study among CSOM patients. Materials and Methods: A total of 380 aural swabs were obtained from patients clinically diagnosed of CSOM. These swabs were cultured for microbial flora. Drugs susceptibility testing was conducted using Kirby–Bauer disc diffusion methods. Statistical Analysis Used: The result was expressed in percentages to investigate the common cause of CSOM, age distribution, and the sensitivity pattern using standard statistical method. Results: The most common bacteriologic organism isolated was Pseudomonas aeruginosa (31.55) while the least common was Streptococcus pneumoniae (0.5%). Antimicrobial profile of the organisms revealed maximum sensitivity (83–100%) to levofloxacin. Conclusions: The bacteriological agent of CSOM has not changed significantly. However, there is a gradual decline in their sensitivity pattern. Slightly different from what is known; levofloxacin stood out as the most sensitive agent in this study.

Keywords: Chronic suppurative otitis media, Levofloxacin, Pseudomonas aeruginosa

How to cite this article:
Kazeem MJ, Aiyeleso R. Current bacteriological profile of chronic suppurative otitis media in a tertiary facility of Northern Nigeria. Indian J Otol 2016;22:157-61

How to cite this URL:
Kazeem MJ, Aiyeleso R. Current bacteriological profile of chronic suppurative otitis media in a tertiary facility of Northern Nigeria. Indian J Otol [serial online] 2016 [cited 2021 Sep 17];22:157-61. Available from: https://www.indianjotol.org/text.asp?2016/22/3/157/187979

  Introduction Top

Chronic suppurative otitis media (CSOM) is an infection of the middle ear cleft lasting for 2 weeks and beyond.[1],[2] It is a disabling ear disease that is characterized by persistent tympanic membrane perforation through which middle ear discharge exudes.

Generally, microbiological culture of the ear discharges implicates Pseudomonas aeruginosa, Proteus spp., and Staphylococcus as the prevalent causative organism worldwide [2],[3],[4] as confirmed by the study done in the same environment about a decade ago.[5] However, emerging evidence of a change in this trend suggests the need to reassess the bacteriology of this disease.[6]

Besides, addressing the menace of increasing antibiotic abuse makes it imperative to carry out this local study.

The aim of the study is to re-evaluate the current bacteriological profile of CSOM and the sensitivity pattern to most of the currently available antibiotics in our environment.

It is a cross-sectional analysis of the bacterial agents associated with CSOM. It is hoped to be a valuable guide to current empirical treatment of the disease in settings where standard laboratory services are scanty.

  Materials and Methods Top

Ethical clearance was obtained from the Hospital's Ethical Committee to carry out the study on patients with CSOM that presented to the tertiary health facility in the state. Patients who presented to the Ear, Nose, and Throat Department, Pediatric Outpatient Department, and General Outpatient Department of the hospital with at least 2 weeks history of otorrhea and otoscopic finding of a permanent tympanic membrane perforation were included in the study while those on antibiotics within the last 2 weeks prior to presentation were excluded from the study.

Aural swabs were obtained from 380 ears with CSOM. The swabs were used to collect ear discharges directly from the perforated tympanic membrane after dry mopping the discharge in the external ear to avoid contamination of middle ear samples. The samples were immediately sent to the hospital's microbiology laboratory where collected samples were inoculated onto MacConkey agar (MCA), blood agar (BA), and chocolate agar plates. MCA and BA plates were inoculated aerobically at 37°C for 24 h in the presence of 2–5% carbon dioxide.[7]

After incubation, the colonial and cultural characteristics of isolates were observed and documented. Gram staining, motility test, and other biochemical tests such as catalase, coagulase, indole, oxidase, citrate, optochin sensitivity disc, test, triple sugar iron, and urease test were also conducted. All results were compared with the identification and biochemical reaction tables (National Committee for Clinical Laboratory Standards).[7]

Bacterial inoculum was prepared and its turbidity was compared to 0.5 ml McFarland standard. A cotton swab was immersed in the inoculum; the swab was then pressed to the side of the tube to remove excess inoculum. It was then used for streaking on Mueller–Hinton agar plate. The antibiotic discs were aseptically placed on the inoculated plate using sterile forceps. The plates were then incubated at 37°C for 24 h after which zone size was measured and recorded. The antibiotic was reported as sensitive or resistant by comparing the zone size to the Kirby–Bauer chart. The control organism used was  Escherichia More Details coli ATCC 25922.[8],[9]

The drugs used were amoxyclav (30 mcg), cotrimoxazole (25 mcg), levofloxacin (5 mcg), ceftazidime (30 mcg), tetracycline (30 mcg), gentamicin (10 mcg), ceftriaxone (30 mcg), and netilmicin (10 mcg).

It is important to state that lack of adequate facility limits the use of Ziehl–Neelsen staining for tubercle bacilli and anaerobic culture.

  Results Top

The number of ears clinically diagnosed of having CSOM by the physicians was 380, out of which 198 (52.1%) were male and 182 (47.9%) were female [Table 1]. The highest prevalence of the disease was observed in the age group below 10 years with 265 (67.4%) cases and the least number of cases was seen in the age group above 60 years having 1 (0.3%) [Table 2]. The side of the ear affected was almost in equal distribution, with the left ear being 185 (48.7%) and the right ear being 182 (47.9%) while 13 (3.4%) were bilateral [Table 3].
Table 1: Sex distribution of chronic suppurative otitis media patients

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Table 2: Age distribution of chronic suppurative otits media patients

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Table 3: Distribution of chronic suppurative otitis media patients according to the side of ear affected

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Out of the 380 middle ear samples analyzed, 360 (94.7%) showed positive growth while 20 (5.3%) had no growth. Among the samples with positive growth, 283 (76.3%) were Gram-negative isolates and 88 (23.7%) were Gram-positive isolates. Further, 338 (93.9%) samples showed growth of single isolates while 22 (6.1%) were mixed isolates.

The frequency of occurrence of the bacterial isolates as shown in [Figure 1] and [Table 4] showed that P. aeruginosa had the highest prevalence of 117 (31.5%) while Streptococcus pneumoniae had the lowest prevalence of 2 (0.5%). Other bacterial isolates were Staphylococcus aureus 86 (23.2%), Proteus mirabilis 50 (13.5%), Proteus vulgaris 31 (8.4%), Klebsiella spp. 34 (9.2%), and E. coli 51 (13.7%).
Figure 1: Pie chart bacterial isolates of chronic suppurative otitis media. Number of isolates (%)

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Table 4: Distribution of bacterial species associated with chronic suppurative otitis media patients

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In [Table 5], the antibiotics used in the treatment of CSOM showed that levofloxacin has the highest sensitivity to all the bacterial isolates whereas amoxyclav, cotrimoxazole, and tetracycline were least sensitive.
Table 5: Sensitivity patterns of bacteria isolates of chronic suppurative otitis media

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Pseudomonas aeruginosa was sensitive to levofloxacin 93.2%, ofloxacin 78.6%, gentamicin 76.9%, ceftazidime 69.2%, and netilmicin 59.8%.

S. aureus showed a sensitivity of 91.9% to levofloxacin. All other antibiotics used were also sensitive with cotrimoxazole, being the least (48.8%) [Table 5].

P. mirabilis showed a sensitivity of 83.0% and 80.9% to levofloxacin and ofloxacin, respectively, followed by ceftazidime and gentamicin 66%, ceftriaxone 57.4%.

E. coli showed a sensitivity of 92.2% and 94.1% to gentamicin and levofloxacin, respectively, followed by ofloxacin 90.2%, ceftazidime 70.6%, ceftriaxone 78.4%, netilmicin 78.4%, and tetracycline 64.7%.

P. vulgaris was sensitive to levofloxacin 96.8%, followed by ofloxacin and gentamicin with 90.3% and 77.4%, respectively, ceftazidime 74.2%, ceftriaxone and netilmicin both at 74.2%, tetracycline 45.2%, and amoxyclav 61.3%.

Klebsiella species showed a sensitivity of 91.2% and 85.3% to levofloxacin and ofloxacin, respectively, followed by netilmicin 76.5%, ceftazidime 70.6%, ceftriaxone 67.6%, tetracycline 53.0%, and gentamicin 50.0%.

S. pneumoniae showed 100% sensitivity to gentamicin, netilmicin, levofloxacin, and ofloxacin.

  Discussion Top

The study showed that 198 (52.1%) patients were male while 182 (47.9%) were female. This is similar to the findings of Nwankwo and Salisu,[5] Okesola and Fasina,[10] and Akingbade et al.[11] but differs from that of Shrestha et al.,[12] which demonstrated more males (44.8%) than females (55.2%). The male preponderance may be due to increased vulnerability of the male child to pathogens and perhaps decreased attention to personal hygiene compared to the female counterparts in this environment.

The peak incidence (67.45%) that occurred between 0 and 10 years age range agrees with the fact that CSOM is predominantly a childhood disease, particularly the under 10. This is partly because the immune system of children is not well developed compared to adult.[13] Furthermore, symptoms such as coughing and vomiting can make translocation of pathogenic organism from the nasopharynx into the middle ear much easier in children where the  Eustachian tube More Detailss are wider, shorter, and straighter compared to that of the adult.

The distribution pattern of the right (47.9%) and the left (48.7%) was almost equal while bilateral was 3.4%. However, the side of the ear affected is of least importance.

In this study, 338 (93.9%) samples were identified as single positive growth while 22 (6.1%) were mixed growth. The percentage of single culture in this study (93.9%) was slightly similar to the previous study (92%).[5] This is probably due to the similarity in the method of sample collection that limits contamination of the ear swabs by the external ear flora.

This current study showed that P. aeruginosa (31.5%) has the highest prevalence of the isolated organism. This correlates well with similar study done in the same institution about a decade ago (31.3%).[5] In addition, this is comparable to the findings of Oguntibeji (31%),[14] Loy et al. (33.3%),[15] Mansoor et al. (40%),[16] and Afolabi et al. (31.3%).[17] On the contrary, Adoga et al. found Klebsiella species (40%) as the predominant organism.[6]

The predominance of Pseudomonas could be attributed to its higher adaptation ability compared to other organism.[18]

S. aureus (23.2%) was the second highest isolate in this study which is similar to the study done by Oni et al.[19] On the contrary, Nwankwo and Salisu [5] observed Proteus spp. (26.1%) as the second most common isolate in a similar study done in the same environment about a decade ago. However, the prevalence of Proteus spp. (21.9%) in this study is similar to that of Nwankwo and Salisu [5] (26.1%).

Furthermore, this study showed that the commonly available antibiotics such as cotrimoxazole, tetracycline, and amoxyclav were generally ineffective against P. aeruginosa, and Proteus species, which is the most prevalent etiological agent of CSOM in our setting. This is in accordance with the reports of Nwabuisi and Ologe.[20] Moreover, the ineffectiveness may be due to indiscriminate use of antibiotics, resulting in the emergence of resistant strains.

Generally, ofloxacin (78.6%), gentamycin (76.9%), and ceftazidime (69.2%) were effective against Pseudomonas in this study. This is slightly similar to the previous study [5] with sensitivity of 88.5%, 94.9%, and 93.9%, respectively. However, this current re-evaluation showed that the sensitivity of these drugs is gradually dropping probably because of widespread self-medication or inappropriate treatment by quacks.

On the other hand, limited availability and high cost make the latter group of drugs more sensitive till date. Although still sensitive, the sensitivity is declining. Thus, there is a need to quickly check the menace of inappropriate treatment of CSOM by quacks and intensify campaign against self-medication.

This downward trend in sensitivity pattern of these antibiotics is however compensated by the discovery of a newer characteristic of levofloxacin in our locality, which is the highest potency of the drug against Pseudomonas (93.2%) and Proteus (83%) in the study.

This is probably because levofloxacin is expensive and not readily available in this locality. Thus, it is far from being abused. In addition, no otic preparation is available for the treatment of CSOM.

  Conclusions Top

The bacteriological agent associated with CSOM has not changed significantly in our environment. However, there is a gradual decline in their sensitivity pattern to a number of antibiotics. Levofloxacin has proven to be a promising drug of choice. Thus, we advocate for its availability in health facilities especially the otic preparations.


We would like to acknowledge Dr. A. D. Salisu (former Head of ENT Department, AKTH), Dr. Dalha Wada Taura (Lecturer at the Department Biological Science, BUK), Mal. Nasiru (Technical head of Microbiology laboratory, AKTH), and all the staff of the concerned departments for their support and assistance during the period the research.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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Couzos S, Lea T, Mueller R, Murray R, Culbong M. Effectiveness of ototopical antibiotics for chronic suppurative otitis media in aboriginal children: A community-based, multicentre, double-blind randomised controlled trial. Med J Aust 2003;179:185-90.  Back to cited text no. 2
Sweeney G, Picozzi GL, Browning GG. A quantitative study of aerobic bacteria in chronic suppurative otitis media. J Infect 1982;5:47-55.  Back to cited text no. 3
Gul S, Eraj A, Ashraf Z. Pseudomonas aeruginosa: A common causative agent of ear infections in South Asian children. Int J Curr Microbial Appl Sci 2014;3:156-60.  Back to cited text no. 4
Nwankwo EO, Salisu AD. Bacteriology of chronic discharging ears of patients in Kano, Nigeria. J Med Lab 2005;49:57.  Back to cited text no. 5
Adoga AA, Bakari A, Afolabi OA, Kodiya AM, Ahmad BM. Bacterial isolates in chronic suppurative otitis media: A changing pattern? Niger J Med 2011;20:96-8.  Back to cited text no. 6
Cheesebrough M. District Laboratory Practice in Tropical Countries. Cambridge: ELBS University Press; 2010. p. 726.  Back to cited text no. 7
MacTaddin J. Biochemical Tests for Identification of Medical Bacteria. 3rd ed. Philadelphia: Lippincott Williams and Wilkins; 1976.  Back to cited text no. 8
Forbes BA, Sahm DF, Weissfeld AS. Bailey and Scott; 1976.cal Bacteria. 3ridge: E th ed. St. Louis, Missouri, USA: Mosby Inc.; 1998.  Back to cited text no. 9
Okesola AO, Fasina OA. Trends in the resistance pattern of bacterial pathogens of otitis media in Ibadan, Nigeria. Afr J Clin Exp Microbiol 2012;13:46-50.  Back to cited text no. 10
Akingbade OA, Awoderu OB, Okerentugba PO, Nwanze JC, Onoh CC, Okonko IO. Bacterial spectrum and their antibiotic sensitivity pattern in children with otitis media in Abeokuta, Ogun state, Nigeria. World Rural Obs 2013;5:1.  Back to cited text no. 11
Shrestha BL, Amatya RC, Shrestha I, Ghosh I. Microbiological profile of chronic suppurative otitis media. Nepal J ENT Head Neck Surg 2011;2:6-7.  Back to cited text no. 12
Akinjogunla OJ, Eghafora NO, Enabulele IO. Aetiologic agent of acute otitis media: Prevalence, antibiotic susceptibility, ty pattern in children with otitis media in Abeokuta, Ogu;1:333-53.  Back to cited text no. 13
Oguntibeji OO. Bacterial isolates from patients with ear infection. Indian J Med Microbiol 2003;21:255-60.  Back to cited text no. 14
Loy AH, Tan AL, Lu PK. Microbiology of chronic suppurative otitis media in Singapore. Singapore Med J 2002;43:296-9.  Back to cited text no. 15
Mansoor T, Musani MA, Khalid G, Kamal M. Pseudomonas aeruginosa in chronic suppurative otitis media: Sensitivity spectrum against various antibiotics in Karachi. J Ayub Med Coll Abbottabad 2009;21:120-3.  Back to cited text no. 16
Afolabi OA, Salaudeen AG, Ologe FE, Nwabuisi C, Nwawolo CC. Pattern of bacterial isolates in the middle ear discharge of patients with chronic suppurative otitis media in a tertiary hospital in north central Nigeria. Afr Health Sci 2012;12:362-7.  Back to cited text no. 17
Ball G, Durand E, Lazdunski A, Filloux A. A novel type II secretion system in Pseudomonas aeruginosa. Mol Microbiol 2002;43:475-85.  Back to cited text no. 18
Oni AA, Bakare RA, Nwaorgu OG, Ogunkunle MO, Toki RA. Bacterial agents of discharging ears and antimicrobial sensitivity patterns in children in Ibadan, Nigeria. West Afr J Med 2001;20:131-5.  Back to cited text no. 19
Nwabuisi C, Ologe FE. Pathogenic agents of chronic suppurative otitis media in Ilorin, Nigeria. East Afr Med J 2002;79:202-5.  Back to cited text no. 20


  [Figure 1]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]

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