A "ritkítószélesztést" sem magyarul, sem angolul nem találom.
Az biztos, hogy a szélesztés az "streak"

"The prepared agar plates should be brought to room temperature. Inoculate plate with specimen and streak for isolation. Incubate at 35ş C for 24-48 hours. This medium is only a part of the identification. Other tests may be required"

"4 - Incubate the inoculated Yersinia PSB Broth at 22°C or 25°C for 2-3 days with agitation or for 5 days without agitation. 5 - Incubate the inoculated Yersinia ITC Broth at 25°C for 48 hours. 6 - Streak a loopful of the enrichment broth onto CIN Agar plates to obtain well isolated colonies and incubate at 30°C for 24 hours. 7 - Add 0.5ml of Yersinia PSB Broth to 4.5ml of KOH solution (0.25g in 100ml of saline solution); with this treated broth streak a plate of CIN Agar and incubate at 30°C for 24 hours. 8 - The typical colonies on CIN Agar must be confirmed by serological and biochemical tests"