Blood culture gram stain, acridine orange stain and direct sensitivity-based antimicrobial therapy of bloodstream infection in patients with trauma.
OBJECTIVE
The purpose of this study was to ascertain if the simple practice of Gram stain, acridine orange stain and direct sensitivity determination of positive blood culture bottles could be used to guide early and appropriate treatment in trauma patients with clinical suspicion of sepsis. The study also aimed to evaluate the error in interpreting antimicrobial sensitivity by direct method when compared to standard method and find out if specific antibiotic-organism combination had more discrepancies. Findings from consecutive episodes of blood stream infection at an Apex Trauma centre over a 12-month period are summarized.


METHODS
A total of 509 consecutive positive blood cultures were subjected to Gram staining. AO staining was done in BacT/ALERT-positive Gram-stain negative blood cultures. Direct sensitivity was performed from 369 blood culture broths, showing single type of growth in Gram and acridine orange staining. Results of direct sensitivity were compared to conventional sensitivity for errors.


RESULTS
No 'very major' discrepancy was found in this study. About 5.2 and 1.8% minor error rates were noted in gram-positive and gram-negative bacteria, respectively, while comparing the two methods. Most of the discrepancies in gram-negative bacteria were noted in beta lactam - beta lactamase inhibitor combinations. Direct sensitivity testing was not reliable for reporting of methicillin and vancomycin resistance in Staphylococci.


CONCLUSIONS
Gram stain result together with direct sensitivity testing is required for optimizing initial antimicrobial therapy in trauma patients with clinical suspicion of sepsis. Gram staining and AO staining proved particularly helpful in the early detection of candidaemia.
Behera
B
B
Department of Microbiology, Jai Prakash Narayan Apex Trauma Centre, All India Institute of Medical Sciences, New Delhi - 110 029, India.
Mathur
P
P
Gupta
B
B
D000165:Acridine Orange; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology*; D001419:Bacteria / Q000187:drug effects* / Q000302:isolation & purification*; D001769:Blood / Q000382:microbiology; D004396:Coloring Agents; D003951:Diagnostic Errors; D005840:Gentian Violet; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D010619:Phenazines; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods; D014947:Wounds and Injuries / Q000150:complications*
D000900:Anti-Bacterial Agents; D004396:Coloring Agents; C035863:Gram's stain; D010619:Phenazines; D000165:Acridine Orange; D005840:Gentian Violet