Microbiology of Para- og Retropharyngeal Abscess

Study Overview
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Brief Summary
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The aims of the study are: Explore the bacteriology of para- and retropharyngeal abscess. Validate the bacterial findings by exploring antibody development against F. necrophorum, F. nucleatum and S. pyogenes. Compare bacteriologic findings in concomitant peritonsillar and parapharyngeal abscesses. Characterize patients with para- and retropharyngeal abscess. Compare the concentration of amylase in para- and retropharyngeal abscesses and neck abscesses without relation to the pharynx or salivary glands. Perform gene-sequencing of F. Necrophorum strains, and compare these with strains recovered from patients with acute tonsillitis, peritonsillar abscess, and Lemierre´s syndrome.

Detailed Description
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Patients: Sixty patients aged 18 years or older with para- or retropharyngeal abscess and 12 patients with neck abscess without relation to the pharynx or salivary glands (controls) will be included at five Danish centers. Estimated time of inclusion: Four years. Data: Symptoms, findings, and other relevant information will be obtained at admission. Data regarding treatment and complications will be obtained after discharge. Samples: Tonsillar surface swabs (bilaterally) Pus aspirate from para- or retropharyngeal abscess Pus aspirate from peritonsillar abscess, if present Biopsy or the entire tonsil (bilaterally) Blood samples (acute and convalescent) Investigations: Bacterial cultures from tonsillar surface swabs, pus aspirates, and tonsillar tissues. Antibody development against F. necrophorum, F. nucleatum and S. pyogenes from the two sera. Gene-sequencing of F. Necrophorum strains. Measurement of amylase concentrations in pus aspirates. Power calculations: Patients needed to show significant increase in anti-F. necrophorum antibody development. Assumptions: The found anti-F. necrophorum antibody levels will be compared to previous findings in electively tonsillectomized patients (9 of 47 patients had two-fold or higher increase in anti-F. necrophorum antibody levels). Level of statistical significance: P = 0.05 Power: 90%. Part of F. necrophorum-positive para- or retropharyngeal patients WHO develop two-fold or higher anti-F. necrophorum antibody levels: 73%. Part of para- or retropharyngeal patients with F. necrophorum: 20%. Number of para- or retropharyngeal patients needed: 60. Concerning comparison of amylase concentrations between patients with para- or retropharyngeal abscess and patients with neck abscesses without relation to the pharynx or salivary glands: Assumptions: Amylase concentration > 20 U/L in 0% of controls. Amylase-concentration > 20 U/L in 50% af patients with para- or retropharyngeal abscess . Inclusion of controls 1:3 compared to patients with para- or retropharyngeal abscess . Level of statistical significance: P = 0.05 Power: 90%. Number of para- or retropharyngeal patients needed: 36. Number of controls needed: 12.

Official Title
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Mikrobiologi Ved Para- og Retropharyngeal Absces

Conditions
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Retropharyngeal Abscess

Intervention / Treatment
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* Biological: Bacteriology
* Procedure: Type of surgery
* Biological: Biochemistry
* Biological: Serology


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: para- or retropharyngeal abscess Exclusion Criteria: refuse to participate

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Para- or retropharyngeal abscess<br>Patients with para- or retropharyngeal abscess. | Biological: Bacteriology<br>* Tonsillar surface swabs, tonsillar tissues, and pus aspirates.<br>Procedure: Type of surgery<br>* Surgical approach and complications.<br>Biological: Biochemistry<br>* Amylase concentration i pus aspirates.<br>Biological: Serology<br>* Levels of antibodies against selected bacteria (F. necrophorum, F. nucleatum, and Group A streptococci) in acute and convalescent sera.<br>|
| Neck abscess<br>Patients with neck abscess without relation to the pharynx or salivary glands. | Biological: Biochemistry<br>* Amylase concentration i pus aspirates.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bacterial findings in aerobic and anaerobic cultures and MALDI-TOF mass spectrometry from para- and retropharyngeal abscesses | Prevalence of potential bacterial pathogens (F. necrophorum, F. nucleatum, Prevotella species, Group A streptococcus, Group C/G streptococcus (large colony forming), S. aureus, H. influenzae, and Viridans streptococci) recovered from aerobic and anaerobic bacterial cultures from pus aspirates. | Within eight hours of patient admission | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Antibody Development against F. necrophorum, F. nucleatum, and S. pyogenes in patients with para- and retropharyngeal abscess | Prevalence of patients with antibody development (at least two-fold increase of antibody level) against selected bacteria (F. necrophorum, F. nucleatum, and Group A streptococci) | Within eight hours of patient admission (serum 1) and two to four weeks after admission (serum 2) | 
| Amylase concentrations in para- and retropharyngeal abscesses vs neck abscesses without relation to the pharynx or salivary glands | Comparison of amylase concentration i pus aspirates between patients with para- and retropharyngeal abscess versus patients with neck abscess not related to the pharynx or salivary glands (controls). | Within eight hours of patient admission. | 
| Comparison of bacterial recoveries in aerobic and anaerobic cultures from patients with concomitant peritonsillar and para-retropharyngeal abscess. | Comparison of prevalence of potential bacterial pathogens (F. necrophorum, F. nucleatum, Prevotella species, Group A streptococcus, Group C/G streptococcus (large colony forming), S. aureus, H. influenzae, and Viridans streptococci) recovered from aerobic and anaerobic bacterial cultures from pus aspirates between concomitant peritonsillar and para-retropharyngeal abscesses. | Within eight hours of patient admission. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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retropharyngeal abscess, parapharyngeal abscess, peritonsillar abscess, bacteriology, Fusobacterium necrophorum