
Comparison of BACTEC MYCO/F Lytic bottle to the Wampole Isolator for recovery of fungal and mycobacterial organisms.
Poornima Ramanan, Emily A. Vetter, Amber A. Milone, Robin Patel, Nancy L. Wengenack
Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.
Background:
The Wampole Isolator lysis centrifugation tube (Alere) and the BACTEC MYCO/F Lytic bottle (Becton Dickinson) are used to enhance recovery of fungal and mycobacterial organisms from blood. Literature supporting this practice is nearly 20 years old, changes have occurred in organism diversity and there is increased demand for cost justified procedures. This study examined whether the Isolator continues to be vital for recovery of these organisms.
Methods:
Blood was collected by a phlebotomy team and distributed into three blood culture receptacles: one Isolator tube with 8 mL of blood and 2 MYCO/F Lytic bottles each with 4 mL of blood. The sediment from the processed Isolator tube was inoculated onto Inhibitory Mold Agar, Emmons Sabouraud Dextrose Agar, and Middlebrook 7H11/7H11 Selective Agar. Plated media was incubated for 30 days and bottles for 42 days on the BACTEC FX instrument. We compared the recovery of fungal and mycobacterial organisms from the Isolator system and MYCO/F Lytic bottles at our institution from December 2011 through February 2016.
Results:
174 (2%) cultures were positive with fungal or mycobacterial isolates from a total of 8293 cultures. Candida spp. (n=57), Mycobacterium avium complex (n=34) and Histoplasma capsulatum (n=28) were the most common organisms. Among 28 isolates of H. capsulatum, 15 grew from the Isolator system only, 1 in the MYCO/F Lytic bottle only and 12 grew from both the Isolator and the MYCO/F Lytic bottles. 3/7 isolates of Cryptococcus neoformans grew in the Isolator system only.
Comparison of BACTEC MYCO/F Lytic bottle to Isolator System
Organism
| Isolator only
| MYCO/F Lytic only
| Both
| Total
|
M. avium complex
| 1
| 12
| 21
| 34
|
H. capsulatum | 15
| 1
| 12
| 28
|
C. neoformans
| 3
| 0
| 4
| 7
|
M. tuberculosis complex
| 0
| 1
| 2
| 3
|
Conclusion:
The Isolator system increases the recovery of certain fungal and mycobacterial organisms from blood as compared with the MYCO/F Lytic bottle alone.

P. Ramanan,
None
A. A. Milone, None
R. Patel, BioFire: Grant Investigator , Grant recipient
Check-Points: Grant Investigator , Grant recipient
Merck: Grant Investigator , Grant recipient
Curetis: Grant Investigator , Grant recipient
Accelerate Diagnostics: Grant Investigator , Grant recipient
Allergen: Grant Investigator , Grant recipient
Qvella: Grant Investigator , Grant recipient
N. L. Wengenack, None