SCIEnTIfIC REpoRTS | (2018) 8:3416 | DOI:10.1038/s41598-018-21520-9
Culture-free bacterial detection
and identication from blood
with rapid, phenotypic, antibiotic
, Usha Kadiyala
, J. Scott VanEpps
& Siu-Tung Yau
The current culture-based approach for the diagnosis of bloodstreams infection is incommensurate
with timely treatment and curbing the prevalence of multi-drug resistant organisms (MDROs) due
to its long time-to-result. Bloodstream infections typically involve extremely low (e.g., <10 colony-
forming unit (CFU)/mL) bacterial concentrations that require a labor-intensive process and as much as
72 hours to yield a diagnosis. Here, we demonstrate a culture-free approach to achieve rapid diagnosis
of bloodstream infections. An immuno-detection platform with intrinsic signal current amplication
was developed for the ultrasensitive, rapid detection, identication (ID) and antibiotic susceptibility
testing (AST) of infections. With its capability of monitoring short-term (1–2 hours) bacterial growth in
blood, the platform is able to provide 84-minute simultaneous detection and ID in blood samples below
the 10 CFU/mL level and 204-minute AST. The susceptible-intermediate-resistant AST capacity was
e current standard for diagnosis of bloodstream infections, including device associated infections (e.g., central
line-associated bloodstream infections, prosthetic valve endocarditis), requires sequential bacterial detection,
identication (ID), and antibiotic susceptibility testing (AST) via traditional blood cultures. is culture-based
three-step diagnostic approach is not optimal with profound clinical implications. First, the time to result for
blood cultures typically ranges from 24 to more than 48 hours
. Typical AST requires an additional 16–24 hours
of culture of the isolated pathogen
. Understanding that early antimicrobial therapy reduces mortality in
bloodstream infections, patients are given empiric, broad-spectrum antibiotics pending culture results. is
one-size-ts-all use of antibiotics results in opportunistic infections, drug-related toxicities, and antibiotic resist-
ance. e prevalence of multi-drug resistant organisms (MDROs) is poised to be one of the greatest threats to
global public health as new MDROs emerge over time
. Each year, in the United States, over 2 million people
acquire serious infections with bacteria that are resistant to one or more of the antibiotics designed to treat those
. At least 23,000 people die each year as a direct result of these antibiotic-resistant infections
more die from other conditions that are complicated by an antibiotic-resistant infection. Second, blood cultures
have low sensitivity. When bacteria in the blood are in low numbers (<10 CFU/mL) growth is suciently slow
to produce a negative result
. Worse still, certain bacteria do not grow at all under standard culture conditions
Up to 30% of prosthetic valve endocarditis is initially culture negative
. ird, cultures are frequently contam-
inated by normal skin ora
, which can grow rapidly and out-compete certain pathogens in the culture media.
Repeating cultures to conrm contamination versus infection further extend the time to diagnosis.
A rapid diagnostic for bacterial detection, ID, and more importantly, AST would reduce exposure time to
broad-spectrum antibiotics and allow for rapid de-escalation to pathogen targeted therapy. Non-culture, molec-
ular diagnostic methods are rapidly being incorporated into standard medical microbiology laboratories. Most
techniques are based on nucleic acid detection and/or amplication (e.g., polymerase chain reaction). However,
Department of Electrical Engineering and Computer Science, Cleveland State University, Cleveland, Ohio, USA.
Department of Emergency Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Michigan Center for
Integrative Research in Critical Care, University of Michigan, Ann Arbor, Michigan, USA.
University of Michigan, Ann Arbor, Michigan, USA.
The Applied Bioengineering Program, Cleveland State University,
Cleveland, Ohio, USA. Correspondence and requests for materials should be addressed to J.S.V. (email: jvane@med.
umich.edu) or S.-T.Y. (email: email@example.com)
Received: 3 August 2017
Accepted: 6 February 2018
Published: xx xx xxxx