title: A method for early detection of antibiotic resistance in positive blood cultures: experience from an oncology centre in eastern India.
abstract: OBJECTIVE
  For antibiotic susceptibility results, conventional culture and sensitivity methods takes 48 hours after a blood culture is flagged positive by automated systems. Early initiation of targeted antibiotic therapy is essential for effective management of sepsis to reduce morbidity, mortality, cost of treatment and prevent antibiotic resistance. Objective of this study was to evaluate Direct Sensitivity Test (DST) as a potential tool to get reliable antibiotic susceptibility results 24 hours earlier.
  
  
  METHODS
  Blood cultures flagged positive between May 2011 to December 2012 by BacT/ALERT were Gram stained. All uni-microbial gram-negative blood cultures were simultaneously cultured and processed for DST from broth using disk diffusion method using British Society of Antimicrobial Chemotherapy (BSAC) guidelines. DST results available next day were compared with conventional antibiotic susceptibility test (AST) performed by Vitek-2 on isolated colonies. Results of DST (test method) and AST (reference method) were compared for agreements or errors.
  
  
  RESULTS
  Of the 840 antibiotic gram-negative organism combinations tested, Categorical and essential agreements were 83.7% and 96.2% respectively. Minor, major and very major errors were 12.5%, 3.33% and 0.47%, respectively.
  
  
  CONCLUSIONS
  DST using disk diffusion from positive blood culture broths helps to initiate early targeted antibiotic therapy. There is high concordance between DST and AST.
authors: G
authors: G
authors: Goel
authors: D
authors: D
authors: Das
authors: S
authors: S
authors: Mukherjee
authors: S
authors: S
authors: Bose
authors: K
authors: K
authors: Das
authors: R
authors: R
authors: Mahato
authors: Consultant Microbiologist, Tata Medical Center, Kolkata, West Bengal, India.
authors: S
authors: S
authors: Bhattacharya
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003428:Cross Infection / Q000175:diagnosis / Q000382:microbiology; D004352:Drug Resistance, Microbial; D042241:Early Diagnosis; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000302:isolation & purification; D006801:Humans; D007194:India; D008826:Microbial Sensitivity Tests / Q000379:methods* / Q000592:standards
chemical_list: D000900:Anti-Bacterial Agents