ECCMID 2015: 25th European Congress of Clinical Microbiology and Infectious Diseases

1. Marjorie Vrignaud, Pierre R. Marcoux, Zoé Buniazet, Pierre L. Joly, Jean Hue, Isabelle Texier-Nogues
CEA-LETI, Département des Technologies pour la Biologie et la Santé, 17 avenue des Martyrs, 38054 Grenoble cedex 9, France
Noninvasive bacteria detection based on the trapping of volatileNoninvasive bacteria detection based on the trapping of volatile
metabolitesmetabolites
Objectives:
• In vitro diagnosis ; specific or nonspecific detection of bacteria
• Rapid and noninvasive detection of bacterial growth in optically unfavourable media (blood, food, …)
• Low-cost and disposable optical sensor
• Detection via volatile organic compound (VOC)
• Trapping of microbial VOC into a transparent nanoporous glass ⇒ change of colour
Sensor made of nanoporous functionalised glass:
• High surface for fast trapping of gas molecules: 600 – 1000 m2
/g
• Sensor can be moulded according to many shapes
Microbial Volatile Organic Compounds (microbial VOC):Endogenous VOC:1
H2S CH3-SHN
H NH2
O
CH3
These VOC do not have intrinsic optical properties ⇒ a reaction with a probe moleculereaction with a probe molecule, within nanopores, is
necessary. It yields a colored or fluorescent compound.
Exogenous VOCs:2
+
Enzymatic substrate carrying a volatile moiety:
⇒ choice of the targeted enzymatic activitychoice of the targeted enzymatic activity: β-glucuronidase (E.
coli), α-glucosidase (S. aureus), C-8 esterase (Salmonella),
β-alanyl arylamidase (P. aeruginosa), etc.
⇒ choice of the optical properties of the MVOC (no probe isno probe is
neededneeded)
Sensor containing a probe molecule Optical transduction (absorption,
fluorescence)
Microbial VOC
volatile moiety
=
OH
NO2
OH
NH2
NH2
for glycosidases for peptidases
o-nitrophenol (oNP)
λmax = 415nm, ε = 3500 L.mol-1
.cm-1
Nanoporous glass as an analyte concentrator
 Low-cost optical sensor
 Noninvasive and continuous monitoring
Outline: 1
S. Crunaire et al., Procedia Chemistry, 2012, 6, 125–131; S. Crunaire et al., Chemosensors, 2014, 2, 171-181;
Z. Buniazet et al., demande de brevet français n°14 60534, 2014.
2
P. Marcoux et al., Patent WO 2013001465; L.H. Guillemot et al., Phys. Chem. Chem. Phys., 2013, 15, 15840–15844
Indole (endogenous VOC) o-nitrophenol (exogenous VOC)
Sulfide endogenous VOC
E. coli (indole +)control H. alvei (indole –)
N
H
When this sensor is exposed to
gaseous indole, a compound
absorbing at 633nm is formed.
When the sulfide sensor is exposed to gaseous
H2S or CH3SH: red shift of the absorption spectrum
before incubation
after incubation (8h)
2×106
cfu/mL are
detected in 5h
(C. freundii, 37°C anaer.)
abs. max. at λ=415nm
Nanoporous glass is moulded following a retroreflector shape.
Retroreflector is placed
into the cap:
⇒ Noninvasive andNoninvasive and
continuous monitoring ofcontinuous monitoring of
the VOC concentration inthe VOC concentration in
gas phasegas phase.
Blood culture (37°C; 15mL)
of E. coli
(100 cfu/mL at t=0).
β-glucuronidase substrate.
Detection at t=8h45.
Blood with bact.
Blood without bact.
• Monitoring through eye-reading or with a photometer
drying
Strategy:
demoulding
mould
Copyright © 2015 Pierre R. MARCOUX, pierre.marcoux@cea.fr