Chronic suppurative otitis media: A microbiological review of 20 years

Pratima Gupta; Saurabh Varshney; Shyam Kishor Kumar; Aroop Mohanty; Mithilesh Kumar Jha

doi:10.4103/indianjotol.INDIANJOTOL_141_19

REVIEW ARTICLE

Year : 2020 | Volume : 26 | Issue : 2 | Page : 59-67

Chronic suppurative otitis media: A microbiological review of 20 years

Pratima Gupta¹, Saurabh Varshney², Shyam Kishor Kumar¹, Aroop Mohanty¹, Mithilesh Kumar Jha¹
¹ Department of Microbiology, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India
² Department of Otorhinolaryngology, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India

Date of Submission	30-Dec-2019
Date of Decision	15-Feb-2020
Date of Acceptance	26-Feb-2020
Date of Web Publication	17-Jul-2020

Correspondence Address:
Dr. Shyam Kishor Kumar
Department of Microbiology, All India Institute of Medical Sciences, Rishikesh, Uttarakhand
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/indianjotol.INDIANJOTOL_141_19

Abstract

Chronic infection of the middle ear cleft for at least 2 weeks or more is known as chronic suppurative otitis media (CSOM). It usually manifests as a complication of acute otitis media. It is more prevalent in developing countries due to various predisposing factors such as malnutrition, overcrowding, poor hygiene, inadequate health care, and recurrent upper respiratory tract infection. Due to advancement in medical facility, India still falls under high prevalence zone. In India, the average prevalence of CSOM is 5.2%. Pseudomonas aeruginosa and Staphylococcus aureus were the predominant isolates in most of the studies. Other common aerobic isolates were Klebsiella spp., Proteus spp., Escherichia coli, Bacteroides fragilis, Prevotella spp., Candida spp., and Aspergillus spp. However, there was no significant geographical variation of pathogens in India. In recent years, there is increased preponderance of multidrug-resistant organisms due to the irrational use of antibiotics, making treatment of CSOM more difficult. Colistin and polymyxin-B were the most effective antibiotics which showed sensitivity against P. aeruginosa by up to 100%. Carbapenems were showing good sensitivity against P. aeruginosa in most of the studies, but there was decreased tendency of sensitivity for piperacillin-tazobactam, amikacin, gentamicin, ceftazidime, and ciprofloxacin. Nine studies isolated methicillin-sensitive S. aureus significantly higher in number than methicillin-resistant S. aureus. For S. aureus, vancomycin and linezolid showed ≥90% sensitivity in most of the studies. Amikacin, gentamicin, erythromycin, and ciprofloxacin were other active drugs against S. aureus, which were showing resistant pattern significantly.

Keywords: Aerobic isolates, chronic suppurative otitis media, multidrug resistant

How to cite this article:
Gupta P, Varshney S, Kumar SK, Mohanty A, Jha MK. Chronic suppurative otitis media: A microbiological review of 20 years. Indian J Otol 2020;26:59-67

How to cite this URL:
Gupta P, Varshney S, Kumar SK, Mohanty A, Jha MK. Chronic suppurative otitis media: A microbiological review of 20 years. Indian J Otol [serial online] 2020 [cited 2023 Mar 22];26:59-67. Available from: https://www.indianjotol.org/text.asp?2020/26/2/59/289946

Introduction

A WHO/CIBA Foundation workshop in 1996 defined “Chronic suppurative otitis media (CSOM) as stage of disease in which there is chronic infection of the middle ear cleft, i.e., Eustachian tube ^{More Details}, middle ear and mastoid, and in which a nonintact tympanic membrane (e.g., perforation or tympanostomy tube) and discharge (otorrhea) are present for at least 2 weeks or more.”^[1] It is also known as chronic active mucosal otitis media, chronic otomastoiditis, or chronic tympanomastoiditis. This is usually a disease of childhood occurring as a sequelae of acute otitis media.^[2] It presents most commonly with hearing loss and suppurative drainage in almost 50% of the cases. It is more prevalent in developing countries due to malnutrition, overcrowding, poor hygiene, inadequate health care, and recurrent upper respiratory tract infection.^[3] It can lead to irreversible complications such as persistent otorrhea, mastoiditis, labyrinthitis, and facial palsy to more serious intracranial abscesses or thromboses.^[4] Hence, an early diagnosis of the causative agent and prompt effective treatment are necessary to avoid such complications.

The most common aerobic bacterial isolates in CSOM are Pseudomonas aeruginosa and Staphylococcus aureus. Escherichia ^{More Details} coli, Proteus mirabilis, Klebsiella spp., Streptococcus pyogenes, Candida spp. and Aspergillus spp. are other common isolates. However, this may vary according to geographical areas and other factors.^[5]

Topical antibiotics in combination with aural toilet are the mainstay of therapy for uncomplicated CSOM.^[6] However, widespread irrational use of antibiotics has led to multidrug-resistant organisms, which, in turn, poses complications, making treatment of CSOM more difficult. In developing countries, multidrug-resistant organisms are rapidly increasing due to the indiscriminate use of antibiotics, overcrowding, poor hospital hygiene, and lack of resources and personnel trained in infection control.^[4] Hence, it is essential to know local microbiological prevalence and antibiotic sensitivity pattern for effective treatment.

This systemic review aims to investigate the changing trends in the etiology and antibiotic sensitivity pattern of CSOM in different parts of India during the past years.

Materials and Methods

Data sources and searches

Published original articles and abstracts in English were searched through Google, Google Scholar, and PubMed search engine. Data sources were included from all parts of India from 1961 to 2019 and included studies on CSOM. Exclusion criteria were (i) studies conducted outside India; (ii) studies of CSOM with complications; and (iii) review articles, case reports, letter to editors, and intervention articles.

We have searched 81 original articles from all parts of India ranging from 1999 to 2019 through various search engines. We found very few studies related to prevalence, so we went back up to 1961 to include as much as possible number of articles discussing about the prevalence of CSOM. Out of the 81 articles, 14 were outside of India. Hence, we left these studies. Out of 67 studies, 7 studies were related to complications and 10 studies were irrelevant to the topic. Hence, we again left these 17 studies. We had 50 studies related to the prevalence and microbiological profile of CSOM.

Results

Demographic profile

We found 13 studies which discussed the prevalence of CSOM [Table 1] in school-going children. The prevalence ranged from 1.4% to 14.7%. Males outnumbered in most of the studies.

Table 1: Prevalence in school-going children in different parts of India

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Microbiological profile

A wide range of aerobic bacteria were isolated in different studies [Table 2]a and [Table 2]b.

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P. aeruginosa and S. aureus were the predominant isolates (19.9%–67.5% and 11.3%–51.9%, respectively), others were Klebsiella spp., Proteus spp., E. coli, and few studies also isolated Serratia marcescens and Shewanella spp.^{[20],[21],[22]}

In five studies which isolated anaerobic bacteria, Bacteroides fragilis was isolated in all, although it was not the most common in every study [Table 3]. Other isolates were Prevotella spp., Fusobacterium spp., and Clostridium spp.

Table 3: Anaerobic isolates of chronic suppurative otitis media (data are expressed in percentage)

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Candida spp. and Aspergillus spp. were the common fungal isolates in most of the studies [Table 4]. Only Juyal et al. reported Penicillium spp. and Mucor in their study.

Table 4: Fungal isolates of chronic suppurative otitis media (data are expressed in percentage)

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[Graph 1] showing prevalence of two common isolates in different region of India.

Antibiotic sensitivity pattern

We compiled the data of antibiotic sensitivity pattern for P. aeruginosa and S. aureus [Table 5] and [Table 6]. For P. aeruginosa, colistin and polymyxin-B showed the highest sensitivity of > 90% in most of the studies. Only Nagraj et al. and Sharma et al. found a lower sensitivity (48.8% and 38%, respectively) against imipenem.^[5],[28] Next to carbapenems and polymyxin, amikacin was the most effective drug noted by most of the studies. Gentamicin was not as effective as amikacin in most of the studies despite of the same class drug. Piperacillin-tazobactam, ceftazidime, and ciprofloxacin were showing decreased sensitivity in most of the studies.

Table 5: Antibiotic sensitivity pattern of Pseudomonas aeruginosa (data are expressed in percentage)

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Table 6: Antibiotic sensitivity pattern of Staphylococcus aureus (data are expressed in percentage)

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For S. aureus, vancomycin and linezolid showed ≥90% sensitivity in most of the studies. Kumar et al. found only 34.5% and 72.4% sensitivity of vancomycin and linezolid, respectively,^[30] and Moorthy et al. found only 57% sensitivity to linezolid.^[38] Ten studies tested sensitivity against methicillin/cefoxitin and mainly found methicillin-sensitive S. aureus and nine of them isolated methicillin-sensitive S. aureus more than methicillin-resistant S. aureus.

Discussion

Prevalence

According to the WHO/CIBA workshop of otitis media experts in 1996, countries having prevalence rate of 1%–2% were considered under low prevalence zone, whereas countries having 3%–6% prevalence rate were considered as high prevalence zone.^[19] In India, the national average prevalence of CSOM is 5.2%, so India falls under the high prevalence zone for CSOM.^[1] In this systemic study, 12 studies were considered from different parts of India for the comparison of the prevalence of CSOM. All the studies included schoolgoing children as a study population. The maximum prevalence was noted as 14.7% from Lucknow, Uttar Pradesh, whereas the minimum prevalence was found as 1.4% from K V Kuppam block, Vellore.^[7],[13] Based on these studies, it may be concluded that the prevalence of CSOM has not much changed in the past many years except few pockets. Although some studies showed prevalence to be low in their studies,^{[11],[13],[15]} other studies even in recent years were showing higher prevalence of CSOM despite the increased medical facility [Table 1]. It may be due to the fact that people are now more aware and they consult doctors for their health issues. There are many other factors which determine the prevalence of CSOM such as younger age, male sex, parental or sibling history of otitis media, early onset of otitis media, low socioeconomic strata, reduced duration of breastfeeding, overcrowding, day-care attendance, recurrent upper respiratory infections, allergic rhinitis, ignorance regarding ear diseases, lack of medical facility, passive smoking, and different geographical location.^{[10],[13],[17]} Almost every predisposing factor is found in the Indian context. In India, as like other developing countries, low socioeconomic condition is associated with the progression of CSOM. Lower socioeconomic class people generally live in congested room and maintain poor personal hygiene, which favor the transmission of infectious agents. Poor living condition is also associated with malnutrition resulting in depressed immune system, which causes increased risk of disease.^[53] Male dominance was seen in most studies, which may be due to males reporting more than females in the hospital or because males are more exposed to outdoor activities.

Microbiological profile

P. aeruginosa was the most common isolate in most of the studies. It was isolated in all studies of different geographic regions. There are many favorable factors which help in the colonization of P. aeruginosa over other bacteria such as minimum nutritional requirement for survival and relative resistant to antibiotics and its antibacterial products, i.e., pyocyanin and bacteriocin. Vartiainen and vartiainen had postulated in their study that in order to improve the results of chronic ear surgery, more attention should be paid to pre-operative treatment of chronically discharging ears, especially those infected by Pseudomonas aeruginosa

they have the capability of surviving and persisting in such conditions by creating a niche for themselves through necrotizing activities of its extracellular enzymes. The niche consists of damaged epithelium, interrupted circulation, and devitalized tissue that protect the organism from the normal host defense mechanisms and antibiotic agents. Besides these, the organism acts as an opportunistic pathogen, flourishes in the external auditory canal, and may cause suppurative disease in contiguous sites.^[28],[29]S. aureus was the second most common organism in most of the studies. Some studies described S. aureus as the most common isolate. Only Sharma et al. did not report S. aureus.^[28] Other bacterial isolates were Klebsiella spp., Proteus spp., E. coli, Enterobacter, Acinetobacter spp., Citrobacter spp., beta hemolytic Streptococci, and Streptococcus pneumoniae. The variations in bacterial isolation rates of different organisms reported by different workers may be as an effect of inappropriate antibiotic uses and climatic and other geographical factors.^[48] A few studies also isolated Serratia marcescens and Schewanella spp.,^{[20],[22],[28]} which may be due to improved isolation/identification techniques.

Very few studies reported anaerobic bacteria in CSOM. This may be due to the fact that isolation of anaerobic bacteria is technically demanding or the association of anaerobic bacteria is usually only with complicated CSOM such as cholesteatoma or granulation tissues.^[29] Most of the studies reported more cases of tubotympanic, which is a noncomplicated form of CSOM. B. fragilis was the common isolate. This review study found minimum 1.8% and maximum 22.4% isolation of anaerobes.^[25],[36] The reason of this wide variation may be due to sampling error, prior administration of antibiotics, or differences in the timing of sampling during the course of disease.

Fungal isolates

Very few studies reported fungal isolates; Juyal et al. studied fungal etiology in detail.^[52] They found highest incidence of fungal infection in the second and third decades of life. Asish et al. also found it in third and fourth decades of life.^[35] Probably, these age groups are more exposed to fungal spore as compared to extreme age groups. Aspergillus spp. were the common isolates in most of the studies. Aspergillus has the capability of growing rapidly and produces a large number of small, dry, easily aerosolized conidia. These conidia can easily contaminate the air. Their growth is further facilitated by cerumen and the slightly acidic pH of the ear canal.^[35]Candida spp. were the second common isolates. Non-albicansCandida, which are less pathogenic than Candida albicans, were also isolated. Asish et al. found higher incidence of fungal infections during rainy season followed by summer season. Hot and humid climate and presence of dust in the environment facilitate the fungal growth.

Antibiotic sensitivity

For P. aeruginosa, polymyxin and carbapenems were acting successfully. However, some studies reported very unsatisfactory result for imipenem.^[5],[28] Aminoglycosides and fluoroquinolones, which are the commonly used antibiotics, have shown many resistant pockets. Similar finding was also seen with piperacillin-tazobactam and ceftazidime, and use of these drugs without knowing the sensitivity pattern may not successfully treat these infections.

As far as concerned S. aureus, methicillin-sensitive S. aureus was isolated in many studies in majority as compared to methicillin-resistant S. aureus.^{[5],[20],[22],[36],[37],[40],[45],[48]} Amikacin showed good sensitivity pattern against S. aureus, although a few results were not satisfactory.^{[24],[35],[38]} Gentamicin was inferior to amikacin in many zones. Ciprofloxacin was not satisfactory in many zones. Although vancomycin and linezolid were showing good results, even these drugs were also showing significant resistant.^{[25],[30],[38]}

These antibiotic sensitive patterns against P. aeruginosa and S. aureus reveal that irrational use of antibiotics must be stopped. Before prescribing an antibiotic, local antibiogram must be kept in mind because the first-line antibiotic such as aminoglycosides and fluoroquinolones are showing many resistant zones. Even the last resort of drugs has resistant pockets, so initiatives must be taken to stop the progression of resistant organisms.

Conclusion

P. aeruginosa and S. aureus are the common isolates in every zone of India. There is no significant change in the prevalence for these two bacteria. There are some other isolates in different zones which may indicate local geographical or climatic variation or impact of inappropriate antibiotic use. Anaerobic bacteria and fungi should never be ignored and samples should be processed appropriately to isolate them also.

In general, upper respiratory tract infections progress to CSOM, so people should be aware enough to take prompt and proper treatment. Once treatment is started, it should be completed because incomplete treatment favors the emergence of resistant organisms. Clinicians should prescribe antibiotics which cover Gram-positive, Gram-negative, and anaerobic bacteria. Culture reports should be made available readily to de-escalate antibiotics properly. Due to irrational and overuse of antibiotics, there are many zones which are showing resistant to first-line antibiotics and only the last option drugs are available for treatment. Hence, antibiotics should be used judiciously and it should be based on local antibiogram. Local antibiogram should be made by continuous and periodic assessment of microbiological and antibiotic sensitivity patterns. It would be helpful to prescribe empirical antibiotics and minimize the emergence of resistant strains as well as reduce the burden of the cost of treatment to the patient.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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