title: Genetic relatedness of clinical and environmental Acinetobacter baumanii isolates from an intensive care unit outbreak.
abstract: BACKGROUND
  Determination of microbial genetic relatedness is important for improving efficiency of infection control measures during hospital outbreaks. This study aimed to analyze the clonal relationships of clinical and environmental Acinetobacter baumannii strains isolated during an outbreak in the intensive care unit (ICU) of a secondary care hospital in Saudi Arabia.
  
  
  METHODS
  Twelve clinical and fourteen environmental A. baumannii isolates identified during an outbreak in February 2013 in the 14-bed adult intensive care unit of a tertiary care hospital in Riyadh, Saudi Arabia, were studied. Bacterial identification and antimicrobial susceptibility testing were carried out using Microscan Walkaway 96 automated system. Determination of clonal diversity was investigated by repetitive-sequence-based polymerase chain reaction (rep-PCR) with the semi-automated DiversiLab system.
  
  
  RESULTS
  The majority of the clinical isolates were from endotracheal tube aspirates (n = 9), one from a wound swab and two were from urine and sputum, respectively. Environmental isolates were from bed railings (n = 10) and with one each from curtain, stethoscope, computer mouse and telephone. Isolates were categorized into 6 clusters (Groups 1-6). Most of the isolates were associated with two clusters namely Groups 2 (n = 11) and 3 (n = 9). All isolates were multidrug resistant showing resistance to three or more classes of antibiotics. One clinical strain from Cluster 3 was resistant to colistin (MIC > 4ug/ml).
  
  
  CONCLUSIONS
  This outbreak was caused by two clonal groups of multidrug resistant A. baumannii. The presence of multiple environmental clones was suggestive of environmental source dissemination via healthcare workers within the ICU.
authors.affiliation: College of Medicine, Alfaisal University, Riyadh, Saudi Arabia. asenok@alfaisal.edu.
authors.forename: Abiola
authors.initials: A
authors.lastname: Senok
authors.forename: Ghada
authors.initials: G
authors.lastname: Garaween
authors.forename: Adeola
authors.initials: A
authors.lastname: Raji
authors.forename: Harish
authors.initials: H
authors.lastname: Khubnani
authors.forename: Garwin
authors.initials: G
authors.lastname: Kim Sing
authors.forename: Atef
authors.initials: A
authors.lastname: Shibl
mesh_terms: D000150:Acinetobacter / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D000328:Adult; D001431:Bacteriological Techniques; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial; D004783:Environmental Microbiology; D005838:Genotype; D006801:Humans; D007362:Intensive Care Units; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D058889:Molecular Typing; D012529:Saudi Arabia / Q000453:epidemiology; D062606:Tertiary Care Centers