title: Microbiology of third and fourth branchial pouch cysts.
abstract: OBJECTIVE
  To identify the most common pathogens involved in infections of third and fourth branchial pouch cysts. Third and fourth branchial pouch cyst infections are an uncommon cause of anterior neck abscesses often confused with other entities, such as thyroglossal duct cysts and thyroid abscesses leading to misdiagnosis, recurrence, and increased morbidity related to a delay in diagnosis and appropriate treatment.
  
  
  METHODS
  Retrospective chart and literature review.
  
  
  METHODS
  Retrospective chart review case series of patients presenting to the Bobby R. Alford Department of Otolaryngology at Texas Children's Hospital from July 2004 to July 2008 with third and fourth branchial pouch cysts.
  
  
  RESULTS
  A total of 11 patients were identified. All patients had left-sided lesions. Eikenella corrodens was found in 60% of cultures and was the most common organism identified in our patient group. Furthermore, 56% of the organisms isolated were anaerobic. All organisms with the exception of Staphylococcus aureus were identified as oral cavity flora.
  
  
  CONCLUSIONS
  Third and fourth branchial pouch cysts provide a communication between the neck and the oral cavity through pyriform sinus tracts. The presence of oral cavity flora in a left anterior neck abscess should raise the suspicion of a branchial pouch anomaly, and subsequently alter therapeutic management.
authors.affiliation: Bobby R. Alford Department of Otolaryngology, Baylor College of Medicine, Houston, Texas, USA. shanep@bcm.edu
authors.forename: Shane
authors.initials: S
authors.lastname: Pahlavan
authors.forename: Waqar
authors.initials: W
authors.lastname: Haque
authors.forename: Kevin
authors.initials: K
authors.lastname: Pereira
authors.forename: Deidre
authors.initials: D
authors.lastname: Larrier
authors.forename: Tulio A
authors.initials: TA
authors.lastname: Valdez
mesh_terms: D000293:Adolescent; D001935:Branchioma / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D016124:Eikenella corrodens / Q000302:isolation & purification; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis*; D006801:Humans; D008297:Male; D018720:Prevotella / Q000302:isolation & purification; D012189:Retrospective Studies