Fig. 3: Phage infection profiles of M. abscessus GD276A and GD276B.
A Twenty-two phage candidates were tested for infection of three clinically isolated strains of M. abscessus. Phage lysates were tenfold serially diluted and spotted onto lawns of M. smegmatis mc2155, and M. abscessus strains GD272, GD276A, and GD276B. B Left panels: Four individual plaques (#1-4) of BPs∆33HTH_HRM10 were picked from a lawn of GD272 (similar to that shown in panel A) and re-plated on M. smegmatis and GD272. The top row labeled ‘BPs’ is the lysate of BPsΔ33HTH_HRM10 grown on M. smegmatis. Right panels: A plaque from each of the four lysates spotted on M. smegmatis in the left panel were picked, propagated on M. smegmatis, and tenfold serial dilutions were plated on M. smegmatis and GD272. The experiment shows that the ability of BPs to infect GD272 is not heritable, and thus is a phenotypic phenomenon in which epigenetic modification is exclusively derived from growth on GD272, but not from M. smegmatis, and therefore overcomes restriction by GD272 when propagated on this strain. C High titer lysates of BPs∆33HTH_HRM10 from the four purified plaques shown in (B) were propagated on GD272, tenfold serially diluted, and plated on M. smegmatis, GD272, GD276A, and GD276B. D Strains GD276A and GD276B were tenfold serially diluted and incubated with either no phage (top row shown with “−“) or with tenfold serially diluted Muddy (rows 2–9) with row two containing 109 PFU. E Cultures of GD276A (2.4 × 108 cells) and GD276B (2.7 × 108 cells) were mixed with 2.4 × 109 and 2.7 × 109 of Muddy, respectively, and incubated in liquid culture for 2 days. Then, 0.1 mL was plated for the growth of survivors on a solid medium. Plates were incubated for 11 days at 37 °C.
