Sink bacteria

On the 26th I streaked some bacteria growing round a sink plug (pink). Suspect: Serratia marcescens. It grew out nicely (kept it warm). Today I did gram stain (gram -ve) and catalase +ve. I stuck a loopful in DNA shield in case I feel like sequencing them later, but S. m. seems likely. Leaving now at room temp to see if growing some out cooler leads to color, TIL s.m. goes pale when incubated warm.