Flow cytometry demonstrates bacteriocin-induced injury to Listeria monocytogenes.
Flow cytometry was used to study the effect of the bacteriocin leucocin B-TA11a on Listeria (L.) monocytogenes. Mixed proportions of dead and live control populations were analyzed by flow cytometry to determine detection limits of the Dead/Live Baclight Bacterial Viability KitTM. High correlations for flow cytometric detection of defined proportions of live or dead cells in mixtures between 10 and 100% of dead (r2 = 0.97) or live (r2 = 0.99) cells were obtained. However, mixtures containing less than 10% of either live or dead control cells gave correlations below 0.72. The growth of L. monocytogenes in the absence and presence of leucocin B-TA11a was analyzed by flow cytometry with Baclight, plate counts, and optical density measurements. Although leucocin B-TA11a initially inhibited listerial growth, the uptake of both Baclight dyes suggested that cells remained viable but became leaky, possibly indicating bacteriocin-induced pore formation in the target membranes.
Swarts
A J
AJ
Department of Microbiology, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.
Hastings
J W
JW
Roberts
R F
RF
von Holy
A
A
D001430:Bacteriocins / Q000494:pharmacology*; D005434:Flow Cytometry / Q000379:methods; D008089:Listeria monocytogenes / Q000187:drug effects*; D008828:Microbiological Techniques; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity
D001430:Bacteriocins; D011933:Reagent Kits, Diagnostic; C090316:leucocin B-Ta11a