title: Minimal Inhibitory Concentration of Ceftazidime and Co-trimoxazole for Stenotrophomonas Maltophilia using E-test.
abstract: BACKGROUND
  Stenotrophomonas maltophilia, previously named as Pseudomonas or Xanthomonas maltophilia, is an important nosocomial pathogen
  
  
  OBJECTIVE
  The purpose of the present study was to investigate the prevalence of S. maltophilia in Iranian hospitals and its susceptibility to available antimicrobial agents.
  
  
  METHODS
  A cross-sectional study in Imam Khomeini Hospital affiliated to Tehran University of Medical Sciences.
  
  
  METHODS
  All blood specimens were sent to the laboratory for blood culture and biochemical analysis. One hundred samples were positive for S. maltophilia. We used disk diffusion and E-test in order to determine minimal inhibitory concentration (MIC) of ceftazidime and co-trimoxazole as the first line antibiotics for S. maltophilia. The tests were performed and interpreted according to the guidelines of Clinical Laboratory Standards Institute (CLSI).
  
  
  METHODS
  Chi-square test and Kappa measurement of agreement were applied as appropriate.
  
  
  RESULTS
  S. maltophilia was the most frequent pathogen (895 specimens; 38.9%) isolated from the samples which were mostly from emergency ward (780 specimens; 33.9%). Ceftazidime MIC(50) and MIC(90) were 2 and 32 μg/ml, respectively (sensitive ≤8 μg/ml and resistant ≥32 μg/ml according to CLSI guideline). MIC(50) and MIC(90) for co-trimoxazole were 0.5 and 2 μg/ml, respectively (sensitive ≤2 μg/ml and resistant ≥4 μg/ml according to CLSI guideline).
  
  
  CONCLUSIONS
  S. maltophilia is the most frequent pathogen in our hospital with a high susceptibility to both ceftazidime and co-trimoxazole.
authors: Department of Pathology, Vali-asr Hospital, Tehran, Iran.
authors: Firoozeh
authors: F
authors: Jamali
authors: Mohammad Ali
authors: MA
authors: Boroumand
authors: Farzad
authors: F
authors: Yazdani
authors: Maryam Sotoudeh
authors: MS
authors: Anvari
authors: Leila
authors: L
authors: Pourgholi
authors: Saeede
authors: S
authors: Mahfouzi
authors: Mohammad
authors: M
authors: Khak