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 Table of Contents  
ORIGINAL ARTICLE
Year : 2014  |  Volume : 16  |  Issue : 1  |  Page : 3-7

Aerobic bacteriological profile and their antibiotic susceptibility in Chronic Suppurative Otitis Media in patients from Mangalore, Karnataka State


1 Department of Microbiology, Father Muller Medical College, Kankanady, Mangalore, Karnataka, India
2 Department of Ear, Nose and Throat, Srinivas Institute of Medical Sciences and Research Centre, Srinivas Integrated Campus, Mukka, Surathkal, Dakshina Kannada, Karnataka, India

Date of Web Publication13-Jun-2014

Correspondence Address:
Anup Kumar Shetty
Department of Microbiology, Father Muller Medical College, Kankanady, Mangalore, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-1282.134454

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  Abstract 

Chronic suppurative otitis media is an infection of the middle ear and mastoid cavity. It is one of the most common causes of deafness. Low social-economic status, overcrowding, malnutrition and poor hygiene are the common risk factors and it commonly affects infants and children. The common pathogens responsible are Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Aspergillus species, Candida species etc. Several studies similar to this have been done previously from various regions of our country and also from several parts of the world. There are no studies done recently from this region to determine the bacteriological profile of aerobic bacteria and their antibiotic susceptibility in this region. The study was done for six months and the sample size was 80. Ear swab culture was done on blood agar, MacConkey agar, and chocolate agar. The culture plates were processed and identification of the isolates and antibiotic susceptibility were done as per standard methods. Samples with bacterial growth were 66 (82.5%), fungal growth were 10 (12.5%) and 4 (5%) samples had no growth. There were 82 isolates of bacteria and fungi from 80 patients. The predominant bacteria were Pseudomonas aeruginosa with 31 (37.80%) isolates followed by Staphylococcus aureus 25 (30.49%). All 31(100%) P. aeruginosa isolates were sensitive to colistin and polymixin B, while 30 (96.8%) isolates showed sensitivity to piperacillin-tazobactam, cefoperazone-sulbactam and aztreonam. Only 21 (67.7%) isolates were sensitive to gentamicin, 23 (74.2%) isolates were sensitive to ciprofloxacin, whereas 24 (77.4%) isolates were sensitive to levofloxacin. All 25 (100%) S. aureus isolates showed sensitivity to vancomycin, teicoplanin and linezolid whereas 23 (92%) isolates showed sensitivity to amikacin, doxycycline and clindamycin. Only one isolate (4%) was sensitive to ampicillin whereas 8 (32%) were sensitive to amoxicillin-clavulanic acid in vitro. P. aeruginosa and S. aureus are the most common aerobic bacterial pathogens in chronic suppurative otitis media. P. aeruginosa showed 100% sensitivity to Colistin and Polymixin B followed by Piperacillin-tazobactam (96.8%), Cefoperazone-sulbactam (96.8%) and Aztreonam (96.8%). S. aureus showed 100% sensitivity to Vancomycin, Teicoplanin and Linezolid followed by Amikacin, Doxycycline and Clindamycin (92% each). Culture and sensitivity should be done in chronic suppurative otitis media before initiating antibiotic therapy.

Keywords: Antibiotic, bacteria, CSOM, mangalore, susceptibility


How to cite this article:
Shetty AK, Shetty A. Aerobic bacteriological profile and their antibiotic susceptibility in Chronic Suppurative Otitis Media in patients from Mangalore, Karnataka State. J Acad Clin Microbiol 2014;16:3-7

How to cite this URL:
Shetty AK, Shetty A. Aerobic bacteriological profile and their antibiotic susceptibility in Chronic Suppurative Otitis Media in patients from Mangalore, Karnataka State. J Acad Clin Microbiol [serial online] 2014 [cited 2017 Sep 19];16:3-7. Available from: http://www.jacmjournal.org/text.asp?2014/16/1/3/134454


  Introduction Top


Chronic suppurative otitis media (CSOM) is an infection of the middle ear and mastoid cavity. [1] It is defined as persistent or intermittent infected discharge of more than three months duration through the perforated or non-intact tympanic membrane caused by bacteria, fungi and viruses resulting in inflammation of the mucosal lining that often results in partial or total loss of the tympanic membrane and the ossicles. [2] CSOM is one of the most common causes of deafness and can cause permanent perforation of the tympanic membrane. Complications of CSOM can be intra and/or extra cranial ranging from facial nerve paralysis, lateral sinus thrombosis, meningitis, brain abscess etc. [1],[3],[4],[5] World Health Organisation (WHO) has estimated that CSOM prevalence in India, Tanzania, Solomon Islands, Guam, Australian Aborigines and Greenland is highest (>4%) and urgent attention is needed to deal with the health problem. [1] It has also resulted in over 28,000 deaths globally in the year 1990 due to various complications. [6] The common risk factors for CSOM are low socio-economic status, overcrowding, malnutrition and poor hygiene. Infants and children are commonly known to be affected with CSOM and it can affect their intellectual, linguistic and psychosocial developments. [1],[7] The common aerobic bacteria causing CSOM are Pseudomonas aeruginosa, Staphylococcus aureus,  Escherichia More Details coli, Klebsiella pneumoniae, Proteus mirabilis etc. The anaerobic bacteria include Bacteroides species, Peptostreptococcus species, Fusobacterium species, Propionibacterium species, Prevotella species, Porphyromonas species etc. Fungi like Aspergillus species (Aspergillus niger) and Candida species are also known to cause CSOM. Aetiological agents of CSOM can vary from one geographical area to the other. [1],[2],[5],[8],[9] Several studies similar to this have been done previously from various regions of our country and also from several parts of the world. There are no studies done recently from this region except for one study which was done 23 years ago and another study on anaerobes done 18 years ago. [10],[11] The aim of this study was to determine the bacteriological profile of aerobic bacteria and their antibiotic susceptibility in this region.


  Materials and methods Top


The study was done for a period of six months from June 2013 to November 2013. Patients attending as outpatients of ear, nose & throat department at various clinics and hospitals in Mangalore, Dakshina Kannada district, Karnataka State, India were included in the study. Patients whose ear condition satisfied the definition of CSOM, were included in the study. Only unilateral CSOM cases were included in the study. All types of patients irrespective of age group, prior antibiotic therapy or diabetes mellitus state were included in the study.

Ear swab was collected from the patients using a sterile swab. Two swabs were collected from each patient. The samples were processed at various reputed microbiological laboratories. One swab was subjected to Gram staining. The second swab was used for aerobic culture. Cultures were done on blood agar, MacConkey agar and chocolate agar. The culture plates were processed and identification of the isolates were done as per standard methods. [12],[13] The antibiotic susceptibility for bacterial isolates was done by modified Kirby-Bauer method as per the Clinical Laboratory Standards Institute guidelines (CLSI). [14] Antibiotics used for testing were Ampicillin (AMP), Amoxicillin-Clavulanic Acid (AMC), Cefazolin (CZO), Cefuroxime (CXM), Ceftriaxone (CEF), Ceftazidime (CAZ), Cefepime (CPM), Cefoxitin (FOX), Piperacillin-Tazobactam (TZP), Ceforperazone Sulbactam (CSL), Aztreonam (ATM), Gentamicin (GEN), Amikacin (AMK), Ciprofloxacin (CIP), Levofloxacin (LVX), Trimethoprim-Sulphamethoxazole (SXT), Doxycycline (DOX), Azithromycin (AZM), Clindamycin (CLI), Vancomycin (VAN), Teicoplanin (TEC), Linezolid, (LNZ), Colistin (COL), Polymixin B (POL) Imipenem (IMP) and Meropenem (MEM). FOX was used for screening Methicillin-resistant Staphylococcus aureus (MRSA). Extended spectrum beta lactamase (ESBL) and inducible CLI resistance detection were also done as per the CLSI guidelines. The antibiotic susceptibility data was analysed using the WHO, WHONET software. [15]


  Results Top


There were 80 patients who fulfilled the inclusion criteria in this period. No formula was used to determine the sample size. There were 82 isolates of bacteria and fungi from 80 patients. Samples with bacterial growth were 66 (82.5%), fungal growth were 10 (12.5%) and 4 (5%) samples had no growth. Out of the 82 isolates, bacterial isolates were 71 (86.59%) and fungal isolates were 11 (13.41%). Mixed bacterial growth with two isolates were seen in 5 (6.25%) samples, mixed fungal growth was seen in 1 (1.25%) and mixed bacterial and fungal growth in 3 (3.75%) samples. Out of the 82 isolates, 42 (51.22%) isolates were Gram negative bacteria, 29 (35.37%) were Gram positive bacteria and 11 (13.41%) were fungi. The details of the bacterial and fungal isolates with their number and percentages are shown in [Table 1]. The predominant bacteria were P. aeruginosa with 31 (37.80%) isolates followed by S. aureus with 25 (30.49%) isolates. The Gram positive bacteria isolated in order of their predominance were S. aureus, Streptococcus pneumoniae, Group A Streptococci (Streptococcus pyogenes), Beta Haeamolytic Streptococci (Non-Group A) and Enterococcus faecalis. The Gram negative bacilli isolated in order of their predominance were P. aeruginosa, E. coli, Klebsiella pneumoniae, Enterobacter species, P. species (non-aeruginosa species), Proteus mirabilis, Acinetobacter species and  Moraxella More Details species. The antibiotic susceptibility for the bacterial isolates are given in [Table 2] and [Table 3]. Aspergillus niger eight isolates (9.76%) was the predominant fungus followed by Candida albicans two (2.44%) and Aspergillus fumigatus one (1.22%). All 31 (100%) P. aeruginosa isolates were sensitive to COL and POL, while 30 (96.8%) isolates showed sensitivity to TZP, CSL and ATM. Only 21 (67.7%) isolates were sensitive to GEN, 23 (74.2%) isolates were sensitive to CIP while 24 (77.4%) isolates were sensitive to LVX. All 25 (100%) S. aureus isolates showed sensitivity to VAN, TEC and LNZ whereas 23 (92%) isolates showed sensitivity to AMK, DOX and CLI. Only one isolate (4%) was sensitive to AMP whereas 8 (32%) were sensitive to AMC in vitro. Out of the 25 Staphylococcus aureus isolates, nine (36%) were MRSA and two (8%) isolates showed inducible CLI resistance. Out of the three Escherichia coli and one Enterobacter species isolates, two (66.67%) isolates and one (100%) isolate were ESBL producers, respectively. Out of the 82 isolates, 23 (28.05%) were from paediatric (up to 18 years) age group and 59 (71.95%) were from adults. All the isolates from paediatric age group were bacterial and there were no fungi isolated. The sex-wise distributions of the patients were 31 (38.75%) males and 49 (61.25%) females.
Table 1: organisms isolated in chronic suppurative otitis media

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Table 2: Antibiotic profi le for bacterial isolates and their percentages of sensitivity

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Table 3: Antibiotic profi le for bacterial isolates and their percentages of sensitivity

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  Discussion Top


CSOM is commonly seen in developing countries. It is estimated by WHO that CSOM prevalence in India, Tanzania, Solomon Islands, Guam, Australian Aborigines and Greenland as the highest (>4%); whereas it is high (2-4%) in Nigeria, Angola, Mozambique, Republic of Korea, Thailand, Philippines, Malaysia, Vietnam, Micronesia, China, Eskimos; low (1-2%) in Brazil, Kenya and; lowest in (<1%) in Gambia, Saudi Arabia, Israel, Australia, United Kingdom, Denmark, Finland and among American Indians. [1] Low social-economic status, overcrowding, malnutrition and poor hygiene are the common risk factors. CSOM is commonly known to affect infants and children and it can affect their intellectual, linguistic and psychosocial developments. [1],[7] The common aerobic bacterial aetiological agents of CSOM include P. aeruginosa, S. aureus, E. coli, Klebsiella pneumoniae, Proteus mirabilis etc. [1],[2],[5],[8],[9] In our study, P. aeruginosa was the most common with 31 isolates (37.8%) followed by 25 isolates of S. aureus (30.49%). The percentage of other isolates [Shown in [Table 1], were less when compared to them. Similar findings have been reported in majority of the studies done earlier in India and other parts of the world. [3],[5],[7],[8],[10] Few studies have reported S. aureus as the most common isolate followed by P. aeruginosa. [2],[4],[6] All 31 (100%) P. aeruginosa isolates were sensitive to COL and POL, while 30 (96.8%) isolates showed sensitivity to TZP, CSL and ATM. Only 21 (67.7%) isolates were sensitive to GEN, 23 (74.2%) isolates were sensitive to CIP while 24 (77.4%) isolates were sensitive to LVX. All 25 (100%) P. aeruginosa showed better sensitivity to CAZ, CPM and CSL than to IMP and MEM. All 25 (100%) S. aureus isolates showed sensitivity to VAN, TEC and LNZ while 23 (92%) isolates showed sensitivity to AMK, DOX and CLI. Only one isolate (4%) was sensitive to AMP while 8 (32%) were sensitive to AMC. Studies have shown increase in MRSA isolates. In this study, nine (36%) isolates were MRSA. All (100%) the MRSA isolates were sensitive to VAN, TEC and LNZ. The antibiotic susceptibility pattern of P. aeruginosa and S. aureus were different when compared to the studies done earlier from various geographical areas and there was no common antibiotic for either P. aeruginosa or S. aureus, which showed highest susceptibility. As per Cochrane review the most effective treatment for CSOM is aural toilet combined with antibiotic therapy. Topical antibiotics are better than systemic antibiotics and combined is no better than topical alone. Topical antibiotics like Neomycin-Polymixin, Gentamicin and fluoroquinolones are usually recommended. [1] In this study, both Gram positive and Gram negative bacteria showed high resistance to topical antibiotics like GEN, CIP, LVX [Table 2] and [Table 3]. Gram positive bacteria showed highest sensitivity to DOX and Gram negative bacteria to POL and COL [Table 3]. Though DOX topical solutions are not easily available, tetracycline can be used as an alternative since DOX represents tetracycline susceptibility. [14] Fluoroquinolones like CIP and LVX and beta lactam drug AMC have been one of the favourite choices for therapy. In contrast to the studies done earlier, [5],[8] this study showed high resistance to CIP, LVX and AMC for both Gram positive and Gram negative bacteria [Table 2] and [Table 3]. The widespread use and misuse of antibiotics have been implicated as the reasons for emergence of antibiotic-resistant bacteria. [3],[5]

Aspergillus species and Candida species are the most common fungi encountered in CSOM. [1],[2] The findings in this study were similar to where Aspergillus niger was the most common fungus isolated followed by Candida albicans and Aspergillus fumigatus [Table 1]. Though anaerobic bacteria like Bacteroides species, Peptostreptococcus species, Fusobacterium species, Propionibacterium species, Prevotella species, Porphyromonas species etc. can cause CSOM, they are rarely isolated in culture. [1],[9],[11] Anaerobic culture was not done in this study. There are few studies done on anaerobes and this area can be further explored.

Gram staining can be used for early screening of the type of bacteria present in the specimen. Due to the chronic nature of CSOM and the possibility of the patient having already undergone prior therapy it would be wiser to initiate appropriate antibiotic therapy only after performing a culture and antibiotic susceptibility. The exact number of patients on prior antibiotic therapy before or at the time of culture and the risk factors were not determined in this study. But all the patients had received one or several courses of antibiotics at one point of time earlier.

Infants and children are commonly known to be affected with CSOM and it can affect their intellectual, linguistic and psychosocial developments. [1],[7] In this study, CSOM was uniformly seen in all age groups and there was uniform distribution of the isolates among all age groups. No predominance of any isolate was seen to a specific age group, except for the Streptococcus species, which were isolated only from paediatric age group. There was no predominance of organisms with respect to sex and there was fairly equal distribution of isolates among males and females.

It was not possible to follow up all patients included in this study after the antibiotic therapy was initiated. The patients who could be followed up responded well after initiating specific therapy. This study cannot recommend one single drug for therapy as the antibiotic susceptibility was variable depending on the organism. The antibiotic susceptibility also varies depending on the region. Empiric therapy is also not recommended as blind therapy without a culture and the antibiotic sensitivity report may lead to prolonged duration of therapy and huge burden to the patient, if the bacteria isolated is resistant to the antibiotic used. Hence, culture and antibiotic sensitivity must be done before initiating the therapy. Studies have to be done on regular intervals in different regions to determine the most common isolates and their susceptibility.


  Conclusion Top


P. aeruginosa and  S.aureus Scientific Name Search  are the most common aerobic bacterial pathogens in CSOM. P. aeruginosa showed 100% sensitivity to Colistin and Polymixin B followed by TZP, CSL and ATM. S. aureus showed 100% sensitivity to Vancomycin, Teicoplanin and Linezolid followed by Amikacin, Doxycycline and Clindamycin. There was no predominance of organism specific to age group or sex. Culture and sensitivity should be done in CSOM before initiating antibiotic therapy.

 
  References Top

1.Chronic suppurative otitis media burden of illness and management options. World Health Organization Geneva Switzerland; 2004.  Back to cited text no. 1
    
2.Shresta BL, Amatya RC, Shresta 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. 2
    
3.Poorey VK, Lyer A. Study of bacterial flora in csom and its clinical significance. Indian J Otolaryngol Head Neck Surg 2002;54:91-5.  Back to cited text no. 3
    
4.Prakash M, Lakshmi K, Anuradha S, Swathi GN. Bacteriological profile and their antibiotic susceptibility pattern of cases of chronic suppurative otitis media. Asian J Pharm Clin Res 2013;6:210-2.  Back to cited text no. 4
    
5.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. 5
    
6.Ahmad S. Antibiotics in chronic suppurative otitis media: A bacteriologic study. Egypt J Ear Nose Throat Allied Sci 2013;14:191-4.  Back to cited text no. 6
    
7.Deb T, Ray D. A study of the bacteriological profile of chronic suppurative otitis media in agartala. Indian J Otolaryngol Head Neck Surg 2012;64:326-9.  Back to cited text no. 7
    
8.Sattar A, Alamgir A, Hussain Z, Sarfraz A, Nasir J, Badar-e-Alam. Bacterial spectrum and their sensitivity pattern in patients of chronic suppurative otitis media. J Coll Physicians Surg Pak 2012;22:128-9.  Back to cited text no. 8
    
9.Brook I. The role of anaerobic bacteria in chronic suppurative otitis media in children: Implications for medical therapy. Anaerobe 2008;14:297-300.  Back to cited text no. 9
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10.Nandy A, Mallya PS, Sivarakan K. Chronic suppurative otitis media- A bacteriological study. Indian J Otolaryngol 1991;43:136-8.  Back to cited text no. 10
    
11.Beena A, Ranjit R, Rajamma R, Indira B, Shivananda PG. Prevalence of anaerobes in chronic suppurative otitis media in coastal Karnataka region. Indian J Otolaryngol Head Neck Surg 1996;48:153-4.  Back to cited text no. 11
    
12.In: Collee JG, Fraser AG, Marmion BP, Simmons A, editors. Mackie and McCartney Practical Medical Microbiology. 14 th ed. Delhi: Churchill Livingstone; 2006.  Back to cited text no. 12
    
13.Winn WC Jr, Allen SD, Janda WM, Koneman EW, Procop GW, Schreckenberger PC, et al. Koneman's color atlas and textbook of diagnostic microbiology. 6 th ed. Philadelphia: Lippincott Williams and Wilkins; 2006.  Back to cited text no. 13
    
14.Performance standards for antimicrobial susceptibility testing; twenty-third infromational supplement. CLSI Document M100-S23. Wayne PA: Clinical and Laboratory Standards Institute; 2013.  Back to cited text no. 14
    
15.World Health Organization. Drug Resistance. WHONET Software.[Internet] 2013. Available from: http://www.who.int/drugresistance/whonetsoftware/en/ [Last cited on 2013 Apr 30].  Back to cited text no. 15
    



 
 
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