title: Bacterial Biofilm in Salivary Gland Stones: Cause or Consequence?
abstract: OBJECTIVE
  The pathogenesis of salivary calculi is not yet clear; however, 2 theories have been formulated: (1) "the classic theory," based on calcium microdeposits in serous and ductal acinous cells, successively discharged into the ducts; (2) "the retrograde theory," based on a retrograde migration of food, bacteria, and so on from the oral cavity to the salivary duct. The aim of the present study is to highlight the role of bacteria and biofilm in stone formation.
  
  
  METHODS
  Case series without comparison.
  
  
  METHODS
  Laboratory of the Department of Anatomical Pathology.
  
  
  METHODS
  Traditional optic microscopy and scanning electron microscopy were carried out on 15 salivary gland calculi that were collected from 12 patients. A qPCR (quantitative real-time polymerase chain reaction) assay was performed to highlight the presence of bacterial DNA on each stone.
  
  
  RESULTS
  Optic microscopy showed formations that-due to their size, shape, and Gram and Giemsa staining-seemed to be Gram-positive bacterial cells. PAS- (periodic acid-Schiff) and alcian-PAS-positive staining matrix was present around them. The ultrastructural observation of the material processed for scanning electron microscopy showed the presence of structures resembling bacterial cells in the middle of the stones, surrounded by soft, amorphous material. Results of qPCR showed the presence of bacterial DNA in the internal part of the tissue sample.
  
  
  CONCLUSIONS
  The presence of bacteria and/or bacterial products resembling biofilm in salivary gland stones supports the "retrograde theory." This evidence may support the hypothesis that biofilm could be the causative effect of lithiasic formations.
authors.affiliation: Department of Sensory Organs, ENT Clinic, Sapienza University of Rome, Rome, Italy massimo.fusconi@libero.it.
authors.forename: Massimo
authors.initials: M
authors.lastname: Fusconi
authors.affiliation: Department of Medical and Surgical Sciences and Biotechnologies, Faculty of Pharmacy and Medicine, Sapienza University of Rome, Latina, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Petrozza
authors.affiliation: Department of Public Health and Infectious Diseases, Microbiology Section, Sapienza University of Rome, Rome, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Schippa
authors.affiliation: Department of Sensory Organs, ENT Clinic, Sapienza University of Rome, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: de Vincentiis
authors.affiliation: Department of Anatomical Pathology, Forensic and Locomotor Apparatus Sciences, Sapienza University of Rome, Rome, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Familiari
authors.affiliation: Department of Public Health and Infectious Diseases, Microbiology Section, Sapienza University of Rome, Rome, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Pantanella
authors.affiliation: Department of Medical and Surgical Sciences and Biotechnologies, Faculty of Pharmacy and Medicine, Sapienza University of Rome, Latina, Italy.
authors.forename: Mirko
authors.initials: M
authors.lastname: Cirenza
authors.affiliation: Department of Public Health and Infectious Diseases, Microbiology Section, Sapienza University of Rome, Rome, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Iebba
authors.affiliation: Department of Anatomical Pathology, Forensic and Locomotor Apparatus Sciences, Sapienza University of Rome, Rome, Italy.
authors.forename: Ezio
authors.initials: E
authors.lastname: Battaglione
authors.affiliation: Department of Sensory Organs, ENT Clinic, Sapienza University of Rome, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Greco
authors.affiliation: Department of Medical-Surgical Biotechnologies and Science, ENT, Sapienza University of Rome, Latina, Italy.
authors.forename: Camilla
authors.initials: C
authors.lastname: Gallipoli
authors.affiliation: Department of Sensory Organs, ENT Clinic, Sapienza University of Rome, Rome, Italy.
authors.forename: Flaminia
authors.initials: F
authors.lastname: Campo
authors.affiliation: Department of Medical-Surgical Biotechnologies and Science, ENT, Sapienza University of Rome, Latina, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Gallo
mesh_terms: D018441:Biofilms; D004269:DNA, Bacterial / Q000032:analysis*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D060888:Real-Time Polymerase Chain Reaction; D015494:Salivary Gland Calculi / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial
keywords: SEM; biofilm; optical microscope; qPCR; sialolithiasis