title: Impact ofStaphylococcus aureusprotein A (spa) genetic typing in cases of prosthetic shunt graft infections.
abstract: BACKGROUND
  In January 2014 an internal audit was performed at the department of surgery, division of vascular surgery of the Medical University Graz, Austria, to assess the short and long-term outcomes of prosthetic shunt graft implantations performed between December 1998 and December 2013. A 10.8 % explantation rate due to graft infection was detected. The majority of the cases were associated withStaphylococcus aureus. The aim of this study was to clarify whether this constitutes a nosocomial problem.
  
  
  METHODS
  Between December 1998 and December 2014 a total of 490 prosthetic shunt grafts were implanted. After exclusion of 54 cases, 436 shunts remained for statistical analysis. Genetic analysis (spa typing) was acquired from three new cases with involvement ofS. aureusin 2014. The impact of several factors (e.g. sex, institute for dialysis, age, type of prosthesis, implantation surgeon and position of shunt) on the shunt graft infection rate was statistically analyzed.
  
  
  RESULTS
  Of the prostheses 14.0 % (61 out of 436) had to be explanted of which 12.4 % (54/436) were due to infection. In 77.8 % (42/54) bacteria were found in blood and/or wound cultures.Staphylococcus aureuswas present in 76.2 % (32/42) of the cases with detected bacteria and in all cases was sensitive to methicillin. The infection rate was not significantly dependent on any of the investigated factors; however, the factor "institute for dialysis" had a remarkable p‑value of 0.060 with the infection rate ranging from 8.5 % to 18.2 % depending on the institution. Three differentS. aureusprotein A (spa) types were found: t015, t359, t6265. The detection of three different spa types means that these patients had different sources ofS. aureusso that a nosocomial problem is very unlikely.
  
  
  CONCLUSIONS
  Genetic typing of spa is a suitable technique for distinguishing between nosocomial and community acquired sources of prosthetic shunt graft infections.
authors.affiliation: Department of Surgery, Division of Vascular Surgery, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Konstantiniuk
authors.affiliation: Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Grisold
authors.affiliation: Department of Surgery, Division of Vascular Surgery, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Schramayer
authors.affiliation: Department of Surgery, Division of Vascular Surgery, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria.
authors.forename: S C
authors.initials: SC
authors.lastname: Santler
authors.affiliation: Department of Surgery, Division of Vascular Surgery, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Koter
authors.affiliation: Department of Surgery, Division of Vascular Surgery, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria.
authors.forename: T
authors.initials: T
authors.lastname: Cohnert
keywords: Infection; Nosocomial; Shunt graft; Spa typing; Staphylococcus aureus