title: In vitro assessment of bacterial translocation during needle insertion through inoculated culture media as a model of arthrocentesis through cellulitic tissue.
abstract: OBJECTIVE
  To determine by use of an in vitro model the potential for translocating sufficient numbers of bacteria into a joint during arthrocentesis through cellulitic tissue to cause sepsis.
  
  
  METHODS
  Culture media containing 4 concentrations of Staphylococcus aureus and needles of 3 sizes.
  
  
  METHODS
  Needles (22, 20, and 19 gauge) were inserted through Mueller-Hinton agar that contained known concentrations of S aureus (10(3),10(4),10(5), and 10(6) CFUs/mL). After a needle exited through the medium, any agar plug within the needle bore was ejected into a sterile syringe and the contaminated portion of the needle was harvested. Sterile saline (0.9% NaCl) solution was used to emulsify the agar plug and wash the contaminated portion of the needle. The resulting solution was cultured to determine the number of bacterial CFUs that could be deposited into a joint during arthrocentesis through contaminated tissue.
  
  
  RESULTS
  Needle gauge and bacterial concentration were both associated with the number of bacterial CFUs deposited after insertion through contaminated agar. Although all needle sizes were capable of bacterial translocation sufficient to cause septic arthritis, ORs for 20- and 22-gauge needles translocating > 33 CFUs of S aureus were significantly higher than the OR for a 19-gauge needle. The ORs for 20- or 22-gauge needles translocating > 33 CFUs of S aureus (the minimum population of S aureus known to cause joint sepsis) were 0.22.
  
  
  CONCLUSIONS
  Results for this in vitro model indicated that caution should be used when performing arthrocentesis through cellulitic tissue.
authors.forename: Travis T
authors.initials: TT
authors.lastname: Smyth
authors.forename: Manuel
authors.initials: M
authors.lastname: Chirino-Trejo
authors.forename: James L
authors.initials: JL
authors.lastname: Carmalt
mesh_terms: D000818:Animals; D000069237:Arthrocentesis / Q000009:adverse effects / Q000662:veterinary; D018988:Bacterial Translocation; D002481:Cellulitis / Q000150:complications / Q000382:microbiology / Q000662:veterinary*; D003470:Culture Media; D004195:Disease Models, Animal; D006734:Horse Diseases / Q000382:microbiology / Q000517:prevention & control*; D006736:Horses; D007592:Joint Diseases / Q000209:etiology / Q000517:prevention & control / Q000662:veterinary*; D009339:Needles / Q000382:microbiology; D018805:Sepsis / Q000209:etiology / Q000517:prevention & control / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000472:pathogenicity / Q000502:physiology
chemical_list: D003470:Culture Media