Can someone please help me? Microbiology Unknown

[cneal8]

Anyone who has ever taken Micro probably had to do an unknown microbe project. Well I've ran all of my tests and, after exhausting Bergey's and Google, I still haven't been able to identify me and my partners unknown. My gut is telling me that we have Enterobacter aerogenes, but the only problem is that our phenol red fermentation test came back (-) for lactose; however, it wasn't your typical negative. It was this:

I know if it isn't completely yellow then it's automatically supposed to be negative, but my tests aren't really leading me anywhere. I know if the media becomes more red or magenta then it's utilizing peptone and not the carbohydrate itself, but why is half of the durham tube red and the other half yellow? I also came up with Indole positive and E. aerogenes is indole negative, but I have no idea what else to go with. Don't Indole test usually produce reliable results?

My test results:

Gram (-)

Bacilli

Motility +

Glucose +/+

Lactose -???

Sucrose +

Mannose +

Mannitol +

MR -

VP +

Citrate +

Malonate +

Catalase +

Oxidase -

Indole +

Urease -

DNase +

Amylase -

TSI y/y

H2S -

Lysine Decarboxylase +

Resistant to: Vancomycin, Erythromycin, and Ampicillin

It's not Klebsiella or Shigella because it's motile. It's not