quality metric regarding blood cultures is the contamination rate. There has been a long-standing recommendation that blood culture contamination rates be kept at or below 3%
for hospitalized patients. This figure is not derived from anything more than the belief that it generally is not possible to maintain rates below 1% and that rates above 5% result in a confounding of the clinician’s ability to distinguish between contaminants and pathogens. Because blood cul-ture contaminants result in increased health care costs, contamination rates above 5% also are associated with in-creased costs. Whether the 3% figure is realistic for outpa-tient settings, particularly in emergency departments, is another unanswered question. For patient safety, quality, and costs, it makes sense to target the lowest possible con-tamination rates, but targeting specific rates should be done with the understanding that different contamination rates occur in different settings.
Another common assessment of quality is the number of blood cultures drawn per septic episode. As noted previously, interpretation of blood culture results depends heavily upon drawing both an adequate volume of blood and more than one culture. Determining the clinical importance of isolates recovered from single blood cultures can be impossible de-pending on the type of isolate recovered. At the same time, collecting more blood cultures than is necessary is wasteful, contributes to phlebotomy-caused anemia, and results only in recovery of more contaminants. For both reasons, labora-tories should monitor the number of blood cultures collected per septic episode.
A third important measurement is the adequacy of fill of blood culture bottles. Weighing filled bottles and comparing weights against those of a known standard most readily achieve this goal. Bottles filled with inadequate volumes of blood diminish yield and should be reported to the provider, with a recommendation to recollect the blood culture. Ade-quacy of filling should be monitored through time and by site so that any patterns of underfilling (or overfilling) can be identified and the appropriate corrective action taken.
SUMMARY
Detection of bacteremia and fungemia remains one of the most important roles of clinical microbiology laboratories.
Despite the development and introduction of a number of novel technologies, the blood culture using liquid-based media still remains the only practicable approach for routine patient care. Molecular detection methods show promise, but the available methods do not have the sensitivityof blood cultures (except for a select few pathogens), provide only limited information regarding antimicrobial suscepti-bility testing, if used alone would not allow for retention of isolates for epidemiologic investigations, at this time are not effectivefor detecting polymicrobial isolates, and are more expensive to use on a routine basis. Other methods such as MALDI-TOF (MS) also can achieve similar results for rapid identification of microorganisms isolated on solid media but currently are not cleared by the FDA for identifi-cation of pathogens directly from blood cultures. Experience has shown that novel technologies rarely replace older tech-nologies but rather serve as adjunctmethods to enhance older technologies. Because the isolation of pathogens from blood serves multiple clinical roles—prognosis, guiding ther-apy, monitoring response to therther-apy, and epidemiology—
any approach to the laboratory detection of bacteremia and fungemia mustbe able tofulfill each of these roles. It is unlikely that any new technology will replace blood cultures entirely in the foreseeable future. What already is happening is that newer technologies are being integrated with blood cultures into an algorithmic approach that takes advantage of the benefits of each method.
REFERENCES
1. Pien BC, Sundaram P, Raoof N, Costa SF, Mirrett S, Woods CW, Reller LB, Weinstein MP. 2010. The clinical and prognostic importance ofpositiveblood cultures in adults. Am J Med 123:819–828.
2. Jin SJ, Kim M, Yoon JH, Song YG. 2013. A new statistical approach topredict bacteremia using electronic medical records. Scand J Infect Dis 45:672–680.
3. Weinstein MP, Towns ML, Quartey SM, Mirrett S, Re-imer LG, Parmigiani G, Reller LB. 1997. The clinical significance of positive blood cultures in the 1990s: a pro-spective,comprehensive evaluationof themicrobiology, epidemiology, andoutcome ofbacteremia and fungemia in adults. Clin Infect Dis 24:584–602.
4. McMurray BR, Wrenn KD, Wright SW. 1997. Usefulness o f b l o o d c u l t u r e s i n p y e l o n e p h r i t i s . A m J E m e r g M e d 15:137–140.
5. Mills AM, Barros S. 2005. Are blood cultures necessary in adults with pyelonephritis? Ann EmergMed 46:285–
287.
6. Thanassi M. 1997. Utility of urine and blood cultures in pyelonephritis. Acad Emerg Med 4:797–800.
7. Velasco M, Martínez JA, Moreno-Martínez A, Horcajada JP, Ruiz J, Barranco M, Almela M, Vila J, Mensa J.
2003. Blood cultures for women with uncomplicated acute pyelonephritis: are they necessary? Clin Infect Dis 37:1127–
1130.
8. Clinical and Laboratory Standards Institute. 2007. Princi-ples and Practice of Blood Cultures. Document M-47. Clinical and Laboratory Standards Institute, Wayne, PA.
9. Cockerill FR,Wilson JW, Vetter EA, Goodman KM, Torgerson CA, Harmsen WS, Schleck CD, Ilstrup DM, Washington JA, Wilson WR. 2004. Optimal testing pa-rameters for blood cultures. Clin Infect Dis 38:1724–1730.
10. Mermel LA, Maki DG. 1993. Detection of bacteremia in adults: consequences of culturing an inadequate volume of blood. Ann Intern Med 119:270–272.
11. Patel R, Vetter EA, Harmsen WS, Schleck CD, Fadel HJ, Cockerill FR III. 2011. Optimized pathogen detec-tion with 30-compared to 20-milliliter blood culture draws. J Clin Microbiol 49:4047–4051.
12. Reimer LG, Wilson ML, Weinstein MP. 1997. Update on the detection of bacteremia and fungemia. Clin Micro-biol Rev 10:444–465.
13. Washington JA. 1975. Blood cultures: principles and tech-niques. Mayo Clin Proc 50:91–95.
14. Weinstein MP, Reller LB, Murphy JR, Lichtenstein KA.
1983. The clinical significance of positive blood cultures:
a comprehensive analysis of500 episodes ofbacteremia and fungemia in adults. I. Laboratory and epidemiologic observations. Rev Infect Dis 5:35–53.
15. Lee A, Mirrett S, Reller LB, Weinstein MP. 2007. Detec-tion of bloodstream infecDetec-tions in adults: how many cultures are needed? J Clin Microbiol 45:3546–3548.
16. Rosner R. 1968. Effect of various anticoagulants and no anticoagulant on ability toisolate bacteria directly from parallel clinical blood specimens. Am J Clin Pathol 68:216–
219.
17. Wilson ML, Weinstein MP, Mirrett S, Reimer LG, Fer-nando C, Meredith FT, Reller LB. 2000. Comparison of iodophor and alcohol pledgets with the Medi-Flex Blood Culture Prep Kit II for preventing contamination of blood cultures. J Clin Microbiol 38:4665–4667.
18. Everts RJ, Vinson EN, Adholla PO, Reller LB. 2001.
Contaminationof catheter-drawn blood cultures. J Clin Microbiol 39:3393–3394.
19. Li J, Plorde JJ, Carlson LG. 1994. Effects of volume and periodicity on bloodcultures. J Clin Microbiol 32:2829–
2831.
20. Baron EJ, Scott JD, Tompkins LS. 2005. Prolonged incu-bation and extensive subculturing do not increase recovery of clinically significant microorganisms from standard auto-mated blood cultures. Clin Infect Dis 41:1677–1680.
21. Fadel HJ, Patel R, Vetter EA, Baddour LM. 2011. Clinical significance of a single Staphylococcus lugdunensis-posi-tive blood culture. J Clin Microbiol 49:1697–1699.
22. Mirrett S, Weinstein MP, Reimer LG, Wilson ML, Reller LB. 2001. Relevance ofthe number ofpositive bottles in determining clinical significance of coagulase-negative staphylococci in blood cultures. J Clin Microbiol 39:3279–
3281.
23. Bryan LE. 1981. Comparison of a slide blood culture system with a supplemented peptone broth culture method. J Clin Microbiol 14:389–392.
24. Pfaller MA, Sibley TK, Westfall LM, Hoppe-Bauer JE, Keating MA, Murray PR. 1982. Clinical laboratory com-parison of a slide blood culture system with a conventional broth system. J Clin Microbiol 16:525–530.
25. Weinstein MP, Reller LB, Mirrett S, Wang WLL, Alcid DV. 1985. Controlled evaluation of Trypticase soy broth in agar slide and conventional blood culture systems. J Clin Microbiol 21:626–629.
26. Weinstein MP, Reller LB, Mirrett S, Wang WLL, Alcid DV. 1985. Clinical comparison of an agar slide blood culture systemwith Trypticase soy broth anda conven-tional blood culture bottle with supplemented peptone broth. J Clin Microbiol 21:815–818.
27. Weinstein MP, Reller LB, Mirrett S, Stratton CW, Re-imer LG, Wang WLL. 1986. Controlled evaluation of the agar slideand radiometric bloodculture systems for the detection of bacteremia and fungemia. J Clin Microbiol 23:221–225.
28. Murray PR, Niles AC, Heeren RL, Curren MM, James LE, Hoppe-Bauer JE. 1988. Comparative evaluation of the Oxoid Signaland Roche Septi-Chek blood culture systems. J Clin Microbiol 26:2526–2530.
29. Weinstein MP, Mirrett S, Reimer LG, Reller LB. 1989.
Effect of agitation and terminal subcultures on yield and
speed of detection of the Oxoid Signal blood culture system versus the Bactec radiometric system. J Clin Mic ro bi ol 27:427–430.
30. Weinstein MP, Mirrett S, Reimer LG, Reller LB. 1990.
Effect of altered headspace atmosphere on yield and speed of detection of the Oxoid Signal blood culture system versus theBactec radiometricsystem. J Clin Microbiol28:795–
797.
31. Weinstein MP, Mirrett S, Reller LB. 1988. Comparative evaluation ofthe Oxoid Signal and Bactec radiometric blood culture systems for the detection of bacteremia and fungemia. J Clin Microbiol 26:962–964.
32. Cockerill FR III, Reed GS, Hughes JG, Torgenson CA, Vetter EA, Harmsen WS, Dale JC, Roberts GD, Ilstrup DM, Henry NK. 1997. Clinical comparison of Bactec 9240 Plus Aerobic/F resin bottles and the Isolator aerobic culture systemfor detection of bloodstream infections.J Clin Microbiol 35:1469–1472.
33. Cockerill FR, Torgenson CA III, Reed GS, Vetter EA, Weaver AL, Dale JC, Roberts GD, Henry NK, Ilstrup DM, Rosenblatt JE. 1996. Clinical comparison of Difco ESP, Wampole Isolator, and Becton Dickinson Septi-Chek aerobic blood culture systems. J Clin Microbiol 34:20–24.
34. Hellinger WC, Zawley JJ, Alvarez S, Hogan SF, Hare-nsen WS, Ilstrup DM, Cockerill FR. 1995. Clinical com-parison of the Isolator and BacT/Alert aerobic blood cul-ture systems. J Clin Microbiol 33:1787–1790.
35. Henry NK,Grewell CM,Van GrevenhofPE, Ilstrup DM, Washington JA II. 1984. Comparison of lysis-centrif-ugation with a biphasic blood culture medium for the recov-ery of aerobic and facultatively anaerobic bacteria. J Clin Microbiol 20:413–416.
36. Henry NK, McLimans CA, Wright AJ, Thompson RL, Wilson WR, Washington JA. 1983. Microbiological and clinical evaluation of the Isolator lysis-centrifugation blood culture tube. J Clin Microbiol 17:864–869.
37. Kiehn TE, Wong B, Edwards FF, Armstrong D. 1983.
Comparative recovery ofbacteria and yeasts from lysis-centrifugation and a conventional blood culture system. J Clin Microbiol 18:300–304.
38. Thorpe TC, Wilson ML, Turner JE, DiGuiseppi JL, Wil-lert M, Mirrett S, Reller LB. 1990. BacT/AWil-lert: an auto-mated colorimetric microbial detection system. J Clin Mi-crobiol 28:1608–1612.
39. Murray PR, Hollick GE, Jerris RC, Wilson ML. 1998.
Multicenter comparison of Bactec 9050 and Bactec 9240 blood culture systems. J Clin Microbiol 36:1601–1603.
40. Waite RT, Woods GL. 1998. Evaluation of Bactec MYCO/
FLytic medium for recovery ofmycobacteria and fungi from blood. J Clin Microbiol 36:1176–1179.
41. Crump JA, Tanner DC, Mirrett S, McKnight CM, Reller LB. 2003. Controlled comparison of Bactec 13A, MYCO/
FLYTIC, BacT/Alert MB, and ISOLATOR10 systems for detection of mycobacteremia. J Clin Microbiol 41:1987–
1990.
42. Crump JA, Morrissey AB, Ramadhani HO, Njau BN, Maro VP, Reller LB. 2011. Controlled comparison of BacT/Alert MB system, manual Myco/F Lytic procedure, and Isolator 10 system for diagnosis of Mycobacterium tuberculosis bacteremia. J Clin Microbiol 49:3054–3057.
43. Jeng K, Gaydos CA, Blyn LB, Yang S, Won H, Matthews H, Toleno D, Hsieh YH, Carroll KC, Hardick J, Masek B, Kecojevic A, Sampath R, Peterson S, Rothman RE.
2012. Comparative analysis of two broad-range PCR assays forpathogen detection inpositive-blood-culture bottles:
PCR–high-resolution melting analysis versus PCR-mass spectrometry. J Clin Microbiol 50:3287–3292.
44. Westh H, Lisby G, Breysse F, Böddinghaus B, Chomarat M, Gant V, Goglio A, Raglio A, Schuster H, Stuber F, Wissing H, Hoeft A. 2009. Multiplex real-time PCR and
blood culture for identification of bloodstream pathogens in patients with suspected sepsis. Clin Microbiol Infect 15:544–
551.
45. Fernández-Cruz A, Marín M, Kestler M, Alcalá L, Rodri-guez-Créixems M, Bouza E. 2013. The value of combining blood culture and SeptiFast data for predicting complicated bloodstream infections caused by gram-positive bacteria or Candida species. J Clin Microbiol 51:1130–1136.
46. Feasey NA, Banada PP, Howson W, Sloan DJ, Mdolo A, Boehme C, Chipungu GA, Allain TJ, Heyderman RS, Corbett EL, Alland D. 2013. Evaluation of Xpert MTB/
RIF for detection oftuberculosis from bloodsamples of HIV-infected adults confirms Mycobacterium tuberculosis bacteremia as an indicator of poor prognosis. J Clin Micro-biol 51:2311–2316.
4 7 . Barenfanger J, Graham DR, Kolluri L, Sangwan G, Lawhorn J, Drake CA, Verhulst SJ, Peterson R, Moja LB, Ertmoed MM, Moja AB, Shevlin DW, Vautrain R, Dallahon CD. 2008. Decreased mortality associated with prompt Gram staining of blood cultures. Am J Clin Pathol 130:870–876.
48. Bauer KA, West JE, Balada-Llasat JM, Pancholi P, Ste-venson KB, Goff DA. 2010. An antimicrobial stewardship program’s impact with rapid polymerase chain reaction meth ic il li n- re si st an t S ta ph yl oc oc cu s a ur eu s/ S. au re us blood culture test in patients with S. aureus bacteremia.
Clin Infect Dis 51:1074–1080.
49. Sango A, McCrater YS, Johnson D, Ferreira J, Guzman N, Jankowski CA. 2013. Stewardship approach for optim-izing antimicrobial therapy through use of a rapid microar-ray assay on blood cultures positive for Enterococcus spe-cies. J Clin Microbiol 51:4008–4011.
50. Stone NRH, Gorton RL, Barker K, Ramnarain P, Kibbler CC. 2013. Evaluation of PNA-FISH yeast traffic light for rapididentification ofyeast directlyfrompositiveblood cultures and assessment of clinical impact. J Clin Microbiol 51:1301–1302.
51. Samuel LP, Tibbetts RJ, Agotesku A, Fey M, Hensley R, Meier FA. 2013. Evaluation of a microarray-based assay for rapid identification of gram-positive organisms and re-sistance markers in positive blood cultures. J Clin Microbiol 51:1188–1192.
52. Wojewoda CM, Sercia L, Navas M, Tuohy M, Wilson D, Hall GS, Procop GW, Richter SS. 2013. Evaluation of the Verigene gram-positive blood culture nucleic acid test for rapid detection of bacteria and resistance determi-nants. J Clin Microbiol 51:2072–2076.
53. Beal SG, Clurca J, Smith G, John J, Lee F, Doern CD, Gander RM. 2013. Evaluation of the nanosphere Verigene gram-positive blood culture assay with the VersaTREK blood culture system and assessment of possible impact on selected patients. J Clin Microbiol 51:3988–3992.
54. Mestas J, Polanco CM, Felsenstein S, Bard JD. 2014.
Performance of the Verigene gram-positive blood culture assay for direct detection of gram-positive organisms and resistance markers in a pediatric hospital. J Clin Microbiol 52:283–287.
55. Mancini N, Infurnari L, Ghidoli N, Valzano G, Clementi N, Burioni R, Clementi M. 2014. Potential impact of a microarray-based nucleic acid assay for rapid detection of gram-negative bacteria and resistance markers in positive blood cultures. J Clin Microbiol 52:1242–1245.
56. Altun O, Almuhayawl M, Ullberg M, Ozenci V. 2013.
Clinical evaluation of the FilmArray blood culture identifi-cation panel in identifiidentifi-cation of bacteria and yeasts form positive blood culture bottles. J Clin Microbiol 51:4130–
4136.
57. Dhiman N, Trienski TL, DiPersio LP, DiPersio JR. 2013.
Evaluation of the BinaxNOW Staphylococcus aureus test for rapid identification of gram-positive cocci from VersaT-REK blood culture bottles. J Clin Microbiol 51:2939–2942.
58. Qian Q, Eichelberger K, Kirby JE. 2014. Rapid identifica-tion of Staphylococcus aureus directly from Bactec blood culture broth by the BinaxNOW S. aureus test. J Clin Microbiol 52:319–320.
59. Moussaoui W, Jaulhac B, Hoffmann A-M, Ludes B, Kost-rzewa M, Riegel P, Prevost G. 2010. Matrix-associated laser desorption ionization time-of-flight mass spectrometry identifies 90% of bacteria directly from blood culture vials.
Clin Microbiol Infect Dis 16:1631–1638.
60. Stevenson LG, Drake SK, Murray PR. 2010. Rapid identi-fication of bacteria in positive blood culture broths by matrix-assisted laser desorption ionization-time of flight mass spectrometry. J Clin Microbiol 48:444–447.
61. Ferreira L, Sanchez-Juanes F, Porras-Guerra I, Garcia-Garcia MI, Garcia-Garcia-Sanchez JE, Gonzalez-Buitrago JM, Munoz-Bellido JL. 2011. Microorganisms direct identifica-tion from blood culture by matrix-assisted laser desorpidentifica-tion/
ionization time-of-flight mass spectrometry. Clin Microbiol Infect 17:541–551.
62. Chen JHK, Ho PL, Kwan GSW, She KKK, Siu GKH, Cheng VCC, Yuen KY, Yam WC. 2013. Direct bacterial identification in positive blood cultures by use of two com-mercial matrix-assisted laser desorption ionization–time of flight mass spectrometry systems. J Clin Microbiol 51:1733–
1739.
63. Lagacé-WiensPRS, Adam HJ, Karlowsky JA, Nichol KA, Pang PF, Guenther J, Webb AA, Miller C, Alfa MJ.
2012. Identification of blood culture isolates directly from positive blood cultures by use of matrix-assisted laser de-sorption ionization–time of flight mass spectrometry and a commercial extraction system: analysis of performance, cost, and turnaround time. J Clin Microbiol 50:3324–3328.
64. Vlek AL,Bonten JM, Boel CH. 2012. Direct matrix-assisted laser desorption ionization time-of-flight mass spec-trometry improves appropriateness of antibiotic treatment of bacteremia. PLoS One 7:e32589.
65. Flayhart D, Borek AP, Wakefield T, Dick J, Carroll KC.
2007. Comparison of Bactec PLUS blood culture media to BacT/Alert FA blood culture media for detection of bacte-rial pathogens in samples containing therapeutic levels of antibiotics. J Clin Microbiol 45:816–821.
66. Rohner P, Pepey B, Auckenthaler R. 1995. Comparison of BacT/Alert with Signal blood culture system. J Clin Microbiol 33:313–317.
67. Wilson ML, Weinstein MP, Reimer LG, Mirrett S, Reller LB. 1992. Controlled comparison of the BacT/Alert and Bactec660/730 nonradiometric blood culture systems.J Clin Microbiol 30:323–329.
6 8 . Weinstein MP, Mirrett S, Reimer LG, Wilson ML, Smith-Elekes S, Chirard CR, Joho KL, Reller LB. 1995.
Controlled evaluation of BacT/Alert standard aerobic and FAN aerobic blood culture bottles for detection of bacter-emia and fungbacter-emia. J Clin Microbiol 33:978–981.
6 9 . Wilson ML, Weinstein MP, Mirrett S, Reimer LG, Smith-Elekes S, Chirard CR, Reller LB. 1995. Controlled evaluation of BacT/Alert standard anaerobic and FAN anaerobic blood culture bottles for the detection of bacter-emia and fungbacter-emia. J Clin Microbiol 33:2265–2270.
70. Kirn TJ, Mirrett S, Reller LB, Weinstein MP. 2014.
Controlled clinical comparison of BacT/Alert FA Plus and FN Plus blood culture media with BacT/Alert FA and FN blood culture media. J Clin Microbiol 52:839–843.
71. Doern CD, Mirrett S, Halstead D, Abid J, Okada P, Reller LB. 2014. Controlled clinical comparison of new pediatric medium with adsorbent polymeric beads (PF Plus) v e r s u s c h a r c o a l - c o n t a i n i n g P F m e d i u m i n t h e B a c T / ALERTbloodculture system. J Clin Microbiol 52:1898-900.
72. Lee D-H, Kim SC, Bae I-G, Koh E-H, Kim S. 2013.
Clinical evaluation ofBacT/Alert FAPlus and FN Plus bottlescompared withstandard bottles. J Clin Microbiol 51:4150–4155.
73. Kirkley BA, Easley DA, Washington JA. 1994. Con-trolled clinical evaluation of Isolator and ESP aerobic blood culture systems for detection of bloodstream infections. J Clin Microbiol 32:1547–1549.
74. Pohlman JK, Kirkley BA, Easley KA, Basille BA, Wash-ington JA. 1995. Controlled clinical evaluation of Bactec Plus Aerobic/F and BacT/Alert FAN bottles for detection of bloodstream infections. J Clin Microbiol 33:2856–2858.
75. McDonald LC, Fune J, Gaido LB, Weinstein MP, Reimer LG, Flynn TM, Wilson ML, Mirrett S, Reller LB. 1996.
Clinical importance of increased sensitivity of BacT/Alert FAN aerobic and anaerobic blood culture bottles. J Clin Microbiol 34:2180–2184.
76. Hardy DJ, Hulbert BB, Migneault PC. 1992. Time to detection of positive BacT/Alert blood cultures and lack of need for routine subculture of 5- to 7-day negative cul-tures. J Clin Microbiol 30:2743–2745.
77. Wilson ML, Mirrett S, Reller LB, Weinstein MP, Reimer LG. 1993. Recovery of clinically important microorganisms from the BacT/Alert blood culture system does not require 7 day testing. Diagn Microbiol Infect Dis 16:31–34.
78. Weinstein MP, Mirrett S, Wilson ML, Reimer LG, Reller LB. 1994. Controlled evaluation of 5 versus 10 milliliters of blood cultured in aerobic BacT/Alert blood culture bot-tles. J Clin Microbiol 32:2103–2106.
79. Nolte FS, Williams JM, Jerris RC, Morello JA. 1993.
Multicenter clinical evaluation of a continuous monitoring blood culture system using fluorescent-sensor technology (Bactec 9240). J Clin Microbiol 31:552–557.
80. Smith JA, Bryce EA, Ngui-Yen JH, Roberts FJ. 1995.
Comparison of Bactec 9240 and BacT/Alert blood culture systems in an adulthospital. J Clin Microbiol 33:1905–
1908.
81. Jorgensen JH, Mirrett S, McDonald LC, Murray PR, Weinstein MP, Fune J, Trippy CW, Masterson M, Reller LB. 1997. Controlled clinical laboratory comparison of Bactec Plus Aerobic/F resin medium with BacT/Alert Aer-o b i c F A N m e d i u m f Aer-o r d e t e c t i Aer-o n Aer-o f b a c t e r e m i a a n d fungemia. J Clin Microbiol 35:53–58.
82. Doern GV, Barton A, Rao S. 1998. Controlled compara-tive evaluation of BacT/Alert FAN and ESP 80A aerobic media as means for detecting bacteremia and fungemia. J Clin Microbiol 36:2686–2689.
83. Welby-Sellenriek PL, Keller DS, Ferrett RJ, Storch GA.
1997. Comparison of the BacT/Alert FAN aerobic and the Difco ESP 80A aerobic bottles for pediatric blood cultures.
J Clin Microbiol 35:1166–1171.
84. Zwadyk P, Pierson CL Jr, Young C. 1994. Comparison of Difco ESP and Organon Teknika BacT/Alert continuous-m o n i t o r i n gb l o o d c u l t u r e s y s t e m s .J C l i n M i c r o b i o l 32:1273–1279.
85. Welby PL, Keller DS, Storch GA. 1995. Comparison of automated Difco ESP blood culture system with biphasic BBL Septi-Chek system for detection of bloodstream infec-tions in pediatric patients. J Clin Microbiol 33:1084–1088.
86. Mirrett S, Hanson KE, Reller LB. 2007. Controlled clini-cal comparison of Versa TREK and BacT/ALERT blood culture systems. J Clin Microbiol 45:299–302.
86. Mirrett S, Hanson KE, Reller LB. 2007. Controlled clini-cal comparison of Versa TREK and BacT/ALERT blood culture systems. J Clin Microbiol 45:299–302.