GNBs, lactose & oxidase

Gram-Negative Bacilli - GNBs

Glucose fermenters / Oxidase negative

1) Enterobacteriacae

• Lactose fermenters

• E. coli – indole positive

• Klebsiella – mucoid colony

• Non-lactose fermenters

• Proteus – swarming colony

• Morganella

• Providencia

• Salmonella enterica – H2S positive

• Shigella – non motile

• S. boydii (serogroup C)

• S. dysenteriae (serogroup A)

• S. flexneri (serogroup B)

• S. sonnei (serogroup D)

• Lactose or non-lactose fermenters

• Citrobacter

• C. freundii

• C. koseri

• Enterobacter

• E. cloacae

• E. aerogenes

• Serratia

• S. marcescens

• Non-Lactose Fermenters/Oxidase negative
  • Yersinia spp.

Glucose fermenters / Oxidase positive

1) Vibrio-Aeromonas-Pleisomonas

• Vibrio – Halophilic (grow in 6% salt)

• V. cholerae

• V. parahaemolyticus

• V. vulnificus

• Aeromonas hydrophila

• Plesiomonas shigelloides

Glucose Non-Fermenters / Oxidase-Negative

1) Acinetobacter

• A. baumannii – glucose oxidizer

• A. lowffii – glucose non-oxidizer

2) Stenotrophomonas maltophilia – glucose oxidizer, rapid malose oxidizer, rapid maltose oxidizer

Glucose Non-Fermenters / Oxidase-Positive

1) Pseudomonas sp

2) Pseudomonas fluorescens group

• P. aeruginosa – growth at 42 C

• P. fluorescens – no growth at 42 C

• P. putida - no growth at 42

3) Burkholderia cepacia – dry, yellow colony on iron-containing media (add B. mallei and B. pseudomallei)

4) Alcaligenes – sweet odour<!--[if !supportLists]--><!--[endif]-->