An electrochemical method for simultaneous detection and identification of Escherichia coli, Staphylococcus aureus and Salmonella choleraesuis using a glucose oxidase-peroxidase composite biosensor.
Quantification of bacterial pollution by amperometric detection at 0.0 V of glucose consumption at a graphite-Teflon-glucose oxidase-peroxidase-ferrocene composite biosensor under flow injection conditions is reported. Using Escherichia coli as the model bacterium, the composition of the growing medium was optimized. A constant glucose concentration of 4.0 x 10(-4) M was added to the culture medium. The relative response to glucose, expressed as the ratio between the amperometric signal and the signal at incubation time t = 0 multiplied by 100, as a function of E. coli concentration, showed a typical behaviour. Limits of detection of 6.5 x 10(2) or 6.5 cfu mL(-1) were achieved after 3 or 7 h of incubation, respectively, with no pre-concentration step. The detection of bacteria did not affect the lifetime of the biosensor. The feasibility of the detection of Staphylococcus aureus and Salmonella choleraesuis throughout the glucose consumption measurement at the composite biosensor is also demonstrated. The capability of bacterial identification by evaluation of bacterial growth in the culture medium containing the antibiotics polymyxin B, vancomycin, erythromycin, bacitracin, chloramphenicol, tetracycline and ciprofloxacin, was investigated. Each micro-organism tested exhibited a different antibiotic susceptibility profile, thus suggesting the possibility of bacteria differentiation. A rapid methodology for screening of bacteria is proposed.
Morales
María Dolores
MD
Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, 28030 Madrid, Spain.
Serra
Beatriz
B
Guzmán-Vázquez de Prada
Ana
A
Reviejo
Angel Julio
AJ
Pingarrón
José Manuel
JM
D001419:Bacteria / Q000302:isolation & purification*; D001432:Bacteriology; D015374:Biosensing Techniques; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004926:Escherichia coli / Q000302:isolation & purification; D017022:Flow Injection Analysis; D005506:Food Contamination; D005947:Glucose / Q000032:analysis; D005949:Glucose Oxidase; D010544:Peroxidases; D019779:Salmonella enterica / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000302:isolation & purification; D014876:Water Pollution
D005949:Glucose Oxidase; D010544:Peroxidases; C023057:glucose peroxidase; D005947:Glucose