Bordetella pertussis Strain Lacking Pertactin and Pertussis Toxin

Abstract

A Bordetella pertussis strain lacking 2 acellular vaccine immunogens, pertussis toxin and pertactin, was isolated from an unvaccinated infant in New York State in 2013. Comparison with a French strain that was pertussis toxin-deficient, pertactin wild-type showed that the strains carry the same 28-kb deletion in similar genomes.

Keywords: Bordetella pertussis; Pertussis; pertactin; pertussis toxin.

Figure 1

Western blot of pertussis toxin (Pt) expression in Bordetella pertussis Tohama I, I979, FR3749, and 3 additional recent isolates. All isolate lanes were loaded with 10-μg of protein, extracted after growth for 48 hours. Protein was transferred with the iBlot Dry Blotting system (Invitrogen, Carlsbad, CA, USA). The primary antibody consisted of 1b7 anti-PTX S1 monoclonal antibody at a concentration of 20 μg/mL diluted in 0.01 M PBS/Tween with 5% milk. The secondary antibody was a FITC-conjugated goat anti-mouse pAb from AbCam, diluted 1:1,000 with 0.01 M PBS/Tween with 5% milk. Lane 1, benchmark protein ladder, 6–180 kDa (Life Technologies, Grand Island, NY, USA); lane 2, Pt positive control, 2 μg; lane 3, empty; lanes 4 and 5, J024 (pertactin (Prn)+/Pt+); lanes 6 and 7, I979 (Prn-/Pt-); lanes 8 and 9, Tohama I (Prn+/Pt+); lanes 10 and 11, I978 (Prn-/Pt+); lanes 12 and 13, FR3749 (Prn+/Pt-); lanes 14 and 15, I974 (Prn-/Pt+).

Figure 2

Map of the 28-kb region deleted in Bordetella pertussis strains I979 and FR3749, compared with vaccine strain Tohama I. Vertical lines indicate the deletion boundaries, at a nucleotide G of the IS481 6-base insertion site motif. The deleted region is flanked by a single IS481 on each end in Tohama I and FR3749; I979 contains a second tandem IS481 downstream of the deletion. In Tohama I, IS1002 is located in the deletion region immediately upstream of IS481, and they share the 6-base motif.