Volume 27, Issue 4 (6-2020)                   RJMS 2020, 27(4): 25-36 | Back to browse issues page

Research code: IR.IUMS.REC 1396.8721215051
Ethics code: IR.IUMS.REC 1396.8721215051

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Sayyahfar S, Bayazian G, Tourchi E. Evaluation of adenoid tissue culture according to biofilm grade and annual rate of upper respiratory tract infection in children with upper airway obstruction. RJMS 2020; 27 (4) :25-36
URL: http://rjms.iums.ac.ir/article-1-5983-en.html
Iran University of Medical Sciences, Tehran, Iran , gr_bayazian@yahoo.com
Abstract:   (2162 Views)

Background: Biofilm, is an organized complex of bacteria that aggregates in an extracellular matrix enriched of polysacchrids, acid nucleic and proteins. Due to this evolved structure, the bacteria in the biofilm becomes highly resistant to the host's defense system and can adhere to the mucosal surface, leading to defects in the host's immune response. At first, bacteria with or without movement, reversibly adhere to the surfaces and then with the multiplication of glycocalyx by bacteria, this connection becomes irreversible. Biofilm growth progresses with the proliferation of baseless bacteria and gradually increases with the addition of other bacteria in the environment. These accumulations act as a chronic bacterial reservoir resistant to common antibiotics, and its debridement appears to justify the patient's clinical symptoms.
Biofilm formations have been observed and reported on the surface of adenoids and tonsils, especially in children with recurrent infections. The adenoid contains a large number of pathogenic bacteria and is more commonly known as a source of bacteria in children with rhinosinusitis than as a cause of mechanical obstruction. Studies have shown that culture of the sample prepared with swab and adenoidectomy is closely related with aerobic and anaerobic flora have been observed in both samples. Most aerobic strains were Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, Moraxella catarrhalis, and most anaerobes were Staphylococcus aureus, Peptostreptococcus, Prevotella and Fusobacterium.
Our sudy aims to evaluate the association between adenoid tissue cultures and microorganisms with biofilms grades in children with upper airway obstruction.
Methods: This cross-sectional study was conducted among the children referred to the ENT clinics of Ali Asghar Children hospital. We included patients with symptoms of nasal obstruction who were candidates for adenoidectomy. Indication of adenoidectomy in this study (inclusion criteria) was existence of confirmed adenoid hypertrophy on examination and lateral neck X-ray (Adenoid view) with symptoms of chronic upper airway obstruction including obstruction sleep apnea, snoring, open mouth breathing, adenoid face, speech disorders and restlessness during sleep (if accompanied by night snoring). Exclusion criteria also included cystic fibrosis, immunodeficiency, respiratory disorders including asthma, and the use of antibiotics during the two weeks prior to surgery. Demografic data of patients were gathered on questionnaire. At this stage, according to the patient history accuracy based on the number of upper airway infections in the past year, patients were divided into five groups less than 5 infections, between 5-8, between 8-12, between 12-15 infections and more than 15 infections per year. After removing the adenoid tissue of the patients by the ENT surgeon in the operating room, a sample was sent to laboratory for culture in normal saline solution and the rest of the sample was cut from several places with a knife after washing with normal saline solution and placed in 2.5% glutaraldehyde solution for fixation. Samples were dried in vacuo, then, after coating the surface of the samples with a layer of gold with a thickness of 30-50 nm (voltage 800v, ​​100 mA), the samples were classified according to the presence and size of biofilm using Philips XL30 Environmental Scanning Electron Microscope (ESEM). Based on the degree of bacterial biofilm in the electron microscope samples , the amount less than 20%  was named as Grade I, 20-40% as Grade II, 40-60% as Grade III, 60-80% as Grade IV and we considered more than 80% as Grade V. Statistical analysis was done by SPSS.
Results: Fifty-one children with a mean age of 7.31 years were enrolled in the study. The average rate of upper airway infection during last year was 9.58. In terms of accompanying symptoms, noctornal snoring and open mouth breathing were seen in all cases. The mean duration of symptoms from onset was 2.5 years (ranging from 2 months to 7.5 years). 30 patients had Grade IV adenoid size in their graphy and noone were graded as grade 1. Biofilm structures in 100% of samples were observed.
According to the achived data, the highest frequency of the organisms was in the biofilm with the grade of 60-80%. Also, biofilm grade above 60% had the highest number of positive cultures. Alpha hemolytic Streptococcus viridans was resulted for 26 samples of adenoid tissue culture and just one sample did not show any bacterial growth. The mean number of infections in different culture groups did not differ significantly (p=0.985, Krusskal Wallis). The mean duration of symptoms did not differ significantly in different culture groups (p=0.159, Krusskal Wallis). There was no statistically significant difference between the gender and different culture groups (p=0.701, Chi2). There was a statistically significant difference between adenoid grade and various groups of bacterial culture (p=0.003, Chi2), the larger the size of the adenoids, the more likely the culture to be positive. As other studies have only examined the most common microorganisms, this study is in fact the first study to evaluate both types of organisms and its comparison with the degree of biofilm. Streptococcus alpha is a hemolytic microorganism that oxidizes RBC hemoglobin to cause a green color in the culture medium. Streptococcus alpha hemolytic viridans is the oral type of this organism, which is a type of normal flora. Studies have shown that the same microorganism can cause pathogenicity.
Disagreement for surgery by parents of some patients was one of the our study limitations. Another limitation of our current study was the difficulty of accurate history of the number of upper airway infections in the past year due to the lack of a recorded medical registry system.
Conclusion: In this study, as presented before, there was a significant relationship between the increase in the surface grade of adenoid biofilm and the number of upper airway infections. Also, the highest frequency of the organisms was observed in biofilms with higher grades, and biofilms above 60% had the highest amount of positive culture. Therefore, this study also confirms that the presence of biofilm in the adenoid as a reservoir of infection causes inflammation and can justify the effectiveness of adenoidectomy as an acceptable therapeutic approch for children with recurrent upper airway infections.

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Type of Study: Research | Subject: ENT Surgery

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