title: Prevalence, risk factors and molecular epidemiology of highly resistant gram negative rods in hospitalized patients in the Dutch region Kennemerland.
abstract: BACKGROUND
  This paper describes (1) the Highly Resistant Gram Negative Rod (HR-GNR) prevalence rate, (2) their genotypes, acquired resistance genes and (3) associated risk factors of HR-GNR colonization among the hospitalized population in the Dutch region Kennemerland.
  
  
  METHODS
  Between 1 October 2013 and 31 March 2014, cross-sectional prevalence measurements were performed in three regional hospitals as part of each hospitals infection control program. Rectal swabs were analyzed at the Regional Public Health Laboratory Kennemerland by direct culturing. Genotypes and acquired resistance genes of positive isolates were determined using Whole Genome Sequencing with the MiSeq instrument (Illumina). Association between several independent variables and HR-GNR positivity was examined using logistic regression models.
  
  
  RESULTS
  Out of 427 patients, 24 HR-GNR positive isolates were recovered from 22 patients, resulting in a regional HR-GNR colonization prevalence (95 % CI) of 5.2 % (3.6-7.9). Of these 22 positive patients, 15 were Extended Spectrum Beta-Lactamase (ESBL) positive (3.5 % (2.1-5.7)), 7 patients were positive for a Fluoroquinolones and Aminoglycosides (Q&A) resistant Enterobacteriaceae (1.6 % (0.8-3.3)) and from one patient (0.2 % (0-1.3)) a Stenotrophomonas maltophilia resistant towards co-trimoxazole was isolated. No carbapenemase producing Enterobacteriaceae (CPE), multi-resistant Acinetobacter species or multi-resistant Pseudomonas aeruginosa were isolated. The ESBL genes found were bla CTX-M-1 (n = 4, 25.0 %), bla CTX-M-15 (n = 3, 18.8 %), bla CTX-M-27 (n = 2, 12.5 %), bla CTX-M-14b (n = 2, 12.5 %), bla CTX-M-9 (n = 2, 12.5 %), bla CTX-M-14 (n = 1, 6.3 %), bla CTX-M-3 (n = 1, 6.3 %), bla SHV-11 (n = 1, 6.3 %) and bla SHV-12 (n = 1, 6.3 %). Being known HR-GNR positive in the past was the only significant associated risk factor for HR-GNR positivity, odds ratio (95 % CI): 7.32 (1.82-29.35), p-value = 0.005.
  
  
  CONCLUSIONS
  Similar ESBL prevalence rates and genotypes (3.5 %) were found in comparison to other Dutch studies. When previously HR-GNR positive patients are readmitted, they should be screened for HR-GNR colonization since colonization with GR-GNRs could be prolonged. We recommend for future studies to include all defined HR-GNRs in addition to ESBLs in prevalence studies, in order to obtain a more comprehensive overview of colonization with HR-GNRs.
authors.affiliation: Department of Epidemiology and Infection Prevention, Regional Public Health Laboratory Kennemerland, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands.
authors.forename: Dennis
authors.initials: D
authors.lastname: Souverein
authors.affiliation: Department of Epidemiology and Infection Prevention, Regional Public Health Laboratory Kennemerland, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands.
authors.forename: Sjoerd M
authors.initials: SM
authors.lastname: Euser
authors.affiliation: Department of Epidemiology and Infection Prevention, Regional Public Health Laboratory Kennemerland, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands.
authors.forename: Bjorn L
authors.initials: BL
authors.lastname: Herpers
authors.affiliation: Department of Epidemiology and Infection Prevention, Regional Public Health Laboratory Kennemerland, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands.
authors.forename: Bram
authors.initials: B
authors.lastname: Diederen
authors.affiliation: Department of Infection Prevention, Spaarne Gasthuis, Haarlem, The Netherlands.
authors.forename: Patricia
authors.initials: P
authors.lastname: Houtman
authors.affiliation: Department of Infection Prevention, Spaarne Gasthuis, Haarlem, The Netherlands.
authors.forename: Marina
authors.initials: M
authors.lastname: van Seventer
authors.affiliation: Department of Infection Prevention, Rode Kruis Ziekenhuis, Beverwijk, The Netherlands.
authors.forename: Ingeborg
authors.initials: I
authors.lastname: van Ess
authors.affiliation: Laboratory for Microbiology and Infection Control, Amphia Hospital, Breda, and University Medical Center, Utrecht, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Kluytmans
authors.affiliation: Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: John W A
authors.initials: JW
authors.lastname: Rossen
authors.affiliation: Department of Epidemiology and Infection Prevention, Regional Public Health Laboratory Kennemerland, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands.
authors.forename: Jeroen W
authors.initials: JW
authors.lastname: Den Boer
keywords: ESBL; HR-GNRs; Netherlands; Prevalence; Risk factors; Whole genome sequencing