A Multicenter Evaluation of Blood Culture Practices, Contamination Rates, and the Distribution of Causative Bacteria.
BACKGROUND
The prognostic value of blood culture testing in the diagnosis of bacteremia is limited by contamination.


OBJECTIVE
In this multicenter study, the aim was to evaluate the contamination rates of blood cultures as well as the parameters that affect the culture results.


METHODS
Sample collection practices and culture data obtained from 16 university/research hospitals were retrospectively evaluated. A total of 214,340 blood samples from 43,254 patients admitted to the centers in 2013 were included in this study. The blood culture results were evaluated based on the three phases of laboratory testing: the pre-analytic, the analytic, and the post-analytic phase.


RESULTS
Blood samples were obtained from the patients through either the peripheral venous route (64%) or an intravascular catheter (36%). Povidone-iodine (60%) or alcohol (40%) was applied to disinfect the skin. Of the 16 centers, 62.5% have no dedicated phlebotomy team, 68.7% employed a blood culture system, 86.7% conducted additional studies with pediatric bottles, and 43.7% with anaerobic bottles. One center maintained a blood culture quality control study. The average growth rate in the bottles of blood cultures during the defined period (1259 - 26,400/year) was 32.3%. Of the growing microorganisms, 67% were causative agents, while 33% were contaminants. The contamination rates of the centers ranged from 1% to 17%. The average growth time for the causative bacteria was 21.4 hours, while it was 36.3 hours for the contaminant bacteria. The most commonly isolated pathogens were Escherichia coli (22.45%) and coagulase-negative staphylococci (CoNS) (20.11%). Further, the most frequently identified contaminant bacteria were CoNS (44.04%).


CONCLUSIONS
The high contamination rates were remarkable in this study. We suggest that the hospitals' staff should be better trained in blood sample collection and processing. Sterile glove usage, alcohol usage for disinfection, the presence of a phlebotomy team, and quality control studies may all contribute to decreasing the contamination rates. Health policy makers should therefore provide the necessary financial support to obtain the required materials and equipment.
Department of Clinical Microbiology, Faculty of Medicine, Sakarya University, Sakarya, Turkey.
Mustafa
M
Altindis
Department of Clinical Microbiology, Faculty of Medicine, Sakarya University, Sakarya, Turkey.
Mehmet
M
Koroglu
Department of Clinical Microbiology, Training and Research Hospital, Sakarya University, Sakarya, Turkey.
Tayfur
T
Demiray
Department of Clinical Microbiology, School of Medicine, Yildirim Beyazit University, Ankara, Turkey.
Tuba
T
Dal
Department of Clinical Microbiology, Meram Medical Faculty Hospital, Necmettin Erbakan University, Konya, Turkey.
Mehmet
M
Ozdemir
Department of Medical Microbiology, Medical Faculty, Medipol University, Istanbul, Turkey.
Ahmet Zeki
AZ
Sengil
Department of Clinical Microbiology, Faculty of Medicine, Sakarya University, Sakarya, Turkey.
Ali Riza
AR
Atasoy
Department of Clinical Microbiology, Meram Medical Faculty Hospital, Necmettin Erbakan University, Konya, Turkey.
Metin
M
Doğan
Department of Clinical Microbiology, School of Medicine, Recep Tayyip Erdogan University, Rize, Turkey.
Aysegul Copur
AC
Cicek
Department of Clinical Microbiology, School of Medicine, Izmir University, Izmir, Turkey.
Gulfem
G
Ece
Department of Clinical Microbiology, School of Medicine, Izmir Katip Celebi University, Izmir, Turkey.
Selcuk
S
Kaya
Department of Clinical Microbiology, School of Medicine, Bezmi Alem University, Istanbul, Turkey.
Meryem
M
Iraz
Department of Clinical Microbiology, School of Medicine, Bezmi Alem University, Istanbul, Turkey.
Bilge Sumbul
BS
Gultepe
Department of Clinical Microbiology, Diyarbakir Training and Research Hospital, Diyarbakir, Turkey.
Hakan
H
Temiz
Department of Clinical Microbiology, School of Medicine, Dicle University, Diyarbakir, Turkey.
Idris
I
Kandemir
Department of Clinical Microbiology, Haydarpasa Numune Hospital, Istanbul, Turkey.
Sebahat
S
Aksaray
Department of Clinical Microbiology, School of Medicine, Ordu University, Ordu, Turkey.
Yeliz
Y
Cetinkol
Department of Clinical Microbiology, School of Medicine, Duzce University, Duzce, Turkey.
Idris
I
Sahin
Department of Clinical Microbiology, School of Medicine, Yuzuncuyil University, Van, Turkey.
Huseyin
H
Guducuoglu
Department of Clinical Microbiology, School of Medicine, Gulhane Military Medical School, Ankara, Turkey.
Abdullah
A
Kilic
Department of Clinical Microbiology, School of Medicine, Abant Izzet Baysal University, Bolu, Turkey.
Esra
E
Kocoglu
Department of Clinical Microbiology, School of Medicine, Erzincan University, Erzincan, Turkey.
Baris
B
Gulhan
Department of Infection Diseases, School of Medicine, Sakarya University, Sakarya, Turkey.
Oguz
O
Karabay
Bacteriological Techniques; Blood Specimen Collection; Blood-Borne Pathogens; Phlebotomy