Enterobacteriaecea cont. (Serratia, proteeae tribe, proteus mirabilis and vulgaris, etc.)

What is the gram stain of Serratia?

gram neg bacilli

Is Serratia oxidase pos or neg?

neg. All Enterics are oxidase neg

Is Serratia motile or non motile?

motile

Which is the most significant species of Serratia?

Serratia marcescens

What a that makes the Serratia species stand out?

Unique in ability to produce proteolytic enzymes (DNAse, lipase, gelatinase)

Where can Serratia be found in the environement?

soil, water

What is a common way people can become infected with Serratia?

can be found to colonize the hands of healthcare personnel

What does Serratia look like on BAP?

pink-brick red pigmentation on BAP

What does Serratia look like on MAC?

colorless to red-brick pigment on MAC, depending on incubation conditions

Does Serratia ferment lactose?

Yes! it is a late lactose fermenter (ONPG pos)

Why do some species appear to be a lactose non-fermenter, but actually are?

Due to the lack of 1 or 2 enzymes required for acid production in lactose fermentation. They have 1 of the required enzymes, which makes their fermentation process sluggish and unnoticed on MAC. Use ONPG test to correct for this

What does Serratia look like on TSI?

K/A

Serratia is indole neg or pos?

neg

Which is Serratia pos for? MR or VP?

pos VP

Is Serratia pos or neg for urease?

neg

What miscellaneous tests is Serratia pos for?

DNAse, lipase, gelatinase

What type of pathogen is Serratia marcescens?

opportunist and nosocomial

Name three disease states that Serratia marcescens can cause besides UTIs.

wound infections, pneumonia and septicemia (in immunosuppressed patients)

What are the three types of Proteeae that we learned about?

Proteus, Morganella, Providencia

What connects the Proteeae tribe? (What do they have in common?)

deaminase pos for lysine and phenylalanine

What is the function of the deaminase enzyme?

removes the amine group from a specific amino acid.

Where can the Proteus species be found in the environment?

soil, water, sewage

Where is Proteus normal flora?

human GI tract

what are 2 unique characteristics about Proteus species?

swarming motility on blood agar, rapid urease activity (urea agar will convert to pink within a few hours)

name two significant Proteus species

P. mirabilis and P. vulgaris

Which of the two (P. mirabilis and P. vulgaris) is the most frequently isolated Proteus species?

P. mirabilis

What does Proteus mirabilis look like on BAP?

gray, swarming, irregular

What does Proteus mirabilis look like on MAC?

colorless (non-lactose fermenter), may swarm, flat irregular

What will Proteus mirabilis look like on TSI?

K/AgH2S

Is Proteus mirabilis indole pos or neg?

neg

Is Proteus mirabilis pos or neg for urea?

rapid pos

Is Proteus mirabilis por or neg for deamination?

pos for phenylalanine and lysine

Is Proteus mirabilis motile?

yes

What does Proteus mirabilis look like on a citrate slant?

slow citrate activity, so usually won't view

How can Proteus mirabilis be presumptively identified?

By the swarming colonies on BAP and oxidase neg.

What are Proteus mirabilis disease states besides UTIs?

pneumonia, septicemia, wound infection

Where can Proteus vulgaris be found in the environment?

soil, water. It is less commonly isolated than P. mirabilis

What does Proteus vulgaris look like on TSI?

K/AgH2S

Is Proteus vulgaris pos or neg for indole?

pos

Is Proteus vulgaris pos or neg for urea?

rapid pos

Is Proteus vulgaris pos or neg for deamination?

Pos (phenylalanine and lysine)

Is Proteus vulgaris motile?

yes. Swarming

What are Proteus vulgaris disease states?

nosocomial and opportunistic cause of UTIs (catheter related), wound infections

Which two out of the five species of Providencia are responsible for human infection?

Providencia retgerri and Providencia stuartii

What are 2 characteristics that all Providencia share?

Part of the enterobacteriacae family and are all deaminase pos

Is Providencia retgerri or Providencia urease pos?

P. retgerri

What is the colonial morphology of Providencia on MAC?

colorless (non-lactose fermenter), round

What does Providencia look like on a TSI slant?

K/A

Is Providencia motile?

yes

Is Providencia pos or neg for citrate?

pos

What are two common disease states due to Providencia?

nosocomial infections (UTI with indwelling catheter, skin infections)

Which Enterobacteriaceae is the only species in its genus?

Morganella morganii

What does Morganella morganii look like on MAC?

colorless (non-lactose fermenter) small, round

What does Morganella morganii look like on TSI?

K/A

Is Morganella morganii citrate pos or neg?

neg

Is Morganella morganii pos or neg for lysine decarboxylase?

neg

Is Morganella morganii pos or neg for deamniase?

pos

Is Morganella morganii pos or neg for urease?

pos

Name 3 disease states caused by Morganella morganii (it is opportunistic)

UTI, GI infection, wound infection

Which Citrobacter is the most common?

Citrobacter freundii

Which Citrobacter is the rarely isolated?

Citrobacter diversus

What does Citrobacter freundii look like on TSI?

A/AgH2S (usually), or K/AgH2S

Is Citrobacter freundii pos or neg for ONPG?

pos. considered a slow or late lactose fermenter

Is Citrobacter freundii citrate pos or neg?

pos

Is Citrobacter freundii pos for MR or VP?

MR

Is Citrobacter freundii pos or neg for indole?

neg

Is Citrobacter freundii motile?

yes

What are some disease states besides UTIs caused by Citrobacter (both species)?

respiratory tract infections, septicemia, wound infections, gastroenteritis

What are the three organisms that produce A/Ag on TSI slant?

Escherichia, Klebsiella, Enterobacter

What are the three organisms that produce K/AgH2S on TSI slant?

Salmonella, Proteus, and Citrobacter (sometimes)

What are the four organisms that produce K/A on TSI slant?

Shigella, Providencia, Serratia, and Morganella morgannii

What is the only organism that produces K/K or K/NC on TSI slant?

Pseudomonas aeruginosa

What is the only organism that produces A/AgH2S on TSI slant?

Citrobacter freundii