title: The evaluation of MRSA surveillance cultures by the number and combinations of anatomical sites.
abstract: BACKGROUND
  The identification of patients infected and/or colonised by methicillin resistantStaphylococcus aureus(MRSA) is necessary for the timely introduction of measures for infection control. We compared the diagnostic efficacy of combinations of MRSA surveillance swabs routinely taken by health institutions in the country.
  
  
  METHODS
  All surveillance samples, which were sent for a microbiological analysis to detect MRSA with the culture method in 2014, in the three departments for medical microbiology of the National Laboratory for Health, Environment and Food, were included in this study.
  
  
  RESULTS
  Among 65,251 surveillance cultures from 13,274 persons, 1,233 (2.1%) were positive (490 positive persons). Prevailing positive surveillance cultures were throat swabs (31.3%), followed by nose swab (31.2%), skin swab (18.9%), perineum (16.4%) and wound swabs (1.4%). The contribution of other samples, such as aspirate, urine and excreta, was under 1%. We found no statistically significant differences in the frequency of detection of a positive patient, if the combination of samples NTS (nose, throat, skin) or NTP (nose, throat, perineum) was analysed. However, statistically significant differences were confirmed when any of the anatomic sites would be omitted from the sets of NTP and NTS (chi square; p<0.01). Adding additional samples resulted in only 24 additional positive patients (4.9%).
  
  
  CONCLUSIONS
  The results indicate that increasing the number of surveillance cultures above three does not add much to the sensitivity of MRSA surveillance, the exception could be wound. The swabs from the perineum and from the skin are exchangeable.
authors.affiliation: National Laboratory for Health, Environment and Food, Department of Clinical Microbiology, Prvomajska 1, 2000 Maribor, Slovenia.
authors.forename: Irena
authors.initials: I
authors.lastname: Grmek Kosnik
authors.affiliation: National Laboratory for Health, Environment and Food, Department of Clinical Microbiology, Prvomajska 1, 2000 Maribor, Slovenia.
authors.forename: Alenka
authors.initials: A
authors.lastname: Storman
authors.affiliation: National Laboratory for Health, Environment and Food, Department of Clinical Microbiology, Prvomajska 1, 2000 Maribor, Slovenia.
authors.forename: Ziva
authors.initials: Z
authors.lastname: Petrovic
authors.affiliation: National Laboratory for Health, Environment and Food, Department of Clinical Microbiology, Prvomajska 1, 2000 Maribor, Slovenia.
authors.forename: Slavica
authors.initials: S
authors.lastname: Robnik
authors.affiliation: National Laboratory for Health, Environment and Food, Department of Clinical Microbiology, Prvomajska 1, 2000 Maribor, Slovenia.
authors.forename: Urska
authors.initials: U
authors.lastname: Dermota
authors.affiliation: National Laboratory for Health, Environment and Food, Department of Clinical Microbiology, Prvomajska 1, 2000 Maribor, Slovenia.
authors.forename: Tjasa
authors.initials: T
authors.lastname: Zohar Cretnik
keywords: MRSA; MRSA control; Staphylococcus aureus; meticillin-resistant; surveillance sample