Comparison of three kinds of blood and two incubation atmospheres for cultivation of Bordetella pertussis on charcoal agar

Abstract

We compared the growth of Bordetella pertussis strains (n = 32) on antibiotic-free and cephalexin (40 ,ug/ml)-containing charcoal agar supplemented with 10% defibrinated horse blood, defibrinated sheep blood, or anticoagulant-containing human blood. Plates were incubated either in air or in an atmosphere with 5 to 10% C02. As assessed by mean colony numbers and rapidity of growth, normal air was preferable to C02 enrichment for incubation. Growth on horse blood agar was more abundant and more rapid than on sheep blood agar, but the difference in general was not statistically significant. Human blood was clearly inferior to both horse and sheep blood.

Laboratory diagnosis of pertussis: state of the art in 1997

“…Cephalexin slightly retards the growth of B. pertussis (88) but does not suppress it (116). Horse blood is more suitable than sheep blood or human blood as a supplement to charcoal agar (44). The shelf-lives of charcoal horse blood agar with cephalexin and of Regan-Lowe transport medium are 4 to 8 weeks (88).…”

“…Desiccation of plates during the prolonged period of incubation (usually a maximum of 7 days, but longer incubation times were reported recently [57]) must be strictly avoided. B. pertussis is a fairly strict aerobe (18), and incubation in ambient air is preferable to incubation in an atmosphere with enriched CO 2 (44).…”