Enterobactericiae are oxidase negative, facultative anaerobes that ferment glucose and convert Nitrates to Nitrites. A famous one is E. coli.
There are two classes to divide these guys. The ones that ferment lactose, and the ones that don't. The ones that do ferment lactose turn McConkee's agar pink. The nonlactose fermenters are clear on McConkee's agar.
Lactose fermenters:
McConKEES
Citrobacter
Klebsiella
E. coli
Enterobacter
Serratia marcescens
Non-lactose fermenters:
ShYPS (Ships)
Shigella
Yersinia enterocolitica
Proteus mirabilus
Salmonella
This isn't quite complete, but it's about as much as you'll need to know, as there are a few others, but they're bacteria that aren't typically considered high yield.
Serratia marcescens is considered to be as an NLF. Serratia appears LF on the MAC because it produces a red pigment called prodigiosin. In the lab we compare the Serratia colony in the BAP and the MAC. The Serratia colony in the BAP has a salmon color to it because of the red pigment.
ReplyDeleteYour Mnemonic still works! just make it singular.
"The appearance of the bacteria on culture media is used
ReplyDeleteto differentiate common members of the Enterobacteriaceae.
For example, fermentation of lactose (detected by
color changes in lactose-containing media such as the
commonly used MacConkey agar) is used to differentiate
some enteric pathogens that do not ferment lactose or do
so slowly (e.g., Salmonella, Shigella, and Yersinia spp., which
are colorless colonies on MacConkey agar) from lactosefermenting
species (e.g., Escherichia, Klebsiella, Enterobacter,
Citrobacter, and Serratia, which are pink-purple colonies on
MacConkey agar)." :::::::: :::::::: [REFERENCE: MEDICAL MICROBIOLOGY, 9th ed.(© 2021), by Patrick R. Murray, PhD, F(AAM), F(IDSA); Ken S. Rosenthal, PhD; Michael A. Pfaller, MD, F(CAP), F(AAM), F(IDSA)] HENCE, Serratia is fermenter!