title: Pathogens causing blood stream infections and their drug susceptibility profile in immunocompromised patients.
abstract: OBJECTIVE
  To determine the types of pathogens causing blood stream infections and their drug susceptibility profile in immunocompromised patients.
  
  
  METHODS
  Cross-sectional, observational study.
  
  
  METHODS
  Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from January to September 2012.
  
  
  METHODS
  Blood culture bottles received from immunocompromised patients were dealt by two methods, brain heart infusion (BHI) broth based manual method and automated BACTEC system. The samples yielding positive growth from either of two methods were further analyzed. The identification of isolates was done with the help of biochemical reactions and rapid tests. Antimicrobial susceptibility of the isolates was carried out as per recommendations of Clinical and Laboratory Standards Institute (CLSI).
  
  
  RESULTS
  Out of the 938 blood culture specimens received from immunocompromised patients, 188 (20%) yielded positive growth. Out of these, 89 (47.3%) isolates were Gram positive and Gram negative each, while 10 (5.3%) isolates were fungi (Candida spp.). In case of Gram positive isolates, 75 (84.3%) were Staphylococcus spp. and 51 (67%) were Methicillin resistant. Amongst Gram negative group 49 (55.1%) isolates were of enterobacteriaceae family, while 40 (44.9%) were non-lactose fermenters (NLF). In vitro antimicrobial susceptibility of Staphylococci revealed 100% susceptibility to vancomycin and linezolid. The enterobacteriaceae isolates had better susceptibility against amikacin 85.7% compared to tigecycline 61.2% and imipenem 59.2%. For NLF, the in vitro efficacy of aminoglycosides was 72.5%.
  
  
  CONCLUSIONS
  The frequency of Gram positive and Gram negative organisms causing blood stream infections in immunocompromised patients was equal. Vancomycin in case of Gram positive and amikacin for Gram negative organisms revealed better in vitro efficacy as compared to other antibiotics.
authors.affiliation: Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Fayyaz
authors.forename: Irfan Ali
authors.initials: IA
authors.lastname: Mirza
authors.forename: Aamer
authors.initials: A
authors.lastname: Ikram
authors.forename: Aamir
authors.initials: A
authors.lastname: Hussain
authors.forename: Tahir
authors.initials: T
authors.lastname: Ghafoor
authors.forename: Umer
authors.initials: U
authors.lastname: Shujat
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology*; D003430:Cross-Sectional Studies; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D016867:Immunocompromised Host; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged
chemical_list: D000900:Anti-Bacterial Agents