Serratia

Question 1

Pigment production at room temperature. “Prodigiosin” – pink-to-red in color

Answer 1

§ Serratia marcescens
§ Serratia rubidea
§ Serratia plymuthica

Question 2

– emits a dirty, musty odor resembling “rotten potatoes”

Answer 2

Serratia odorifera

Question 3

Serratia are all

Answer 3

Sucrose fermenters

Question 4

Note: All Serratia species except for______ are late lactose fermenters, positive for
ONPG.

All are DNAse, Lipase, and Gelatinase positive (differential for other members of the family Enterobacteriaceae.

Serratia species are known for their resistance to a wide range of antimicrobials.

Answer 4

Serratia fonticola

Question 5

– the most clinically significant species
§ Frequently found in hospital-acquired infections of the urinary tract

§ Bacteremic outbreaks in nurseries and cardiac surgery and burn units.

§ Contamination of antiseptic solution used for joint injections has result in an epidemic of septic arthritis.

Answer 5

Serratia marcescens

Question 6

Serratia odorifera biogroups

– isolated predominantly from the respiratory tract and is positive for the fermentation of sucrose and raffinose, and is positive for ornithine decarboxylation

Answer 6

§ S.odorifera biogroup 1

Question 7

Serratia odorifera biogroups

– isolated from blood and CSF and is negative for the fermentation of sucrose and raffinose, and negative for ornithine decarboxylation.

o 50% of isolates are indole positive

Answer 7

§ S.odorifera biogroup 2

Question 8

Serratia marcescens
Laboratory Diagnosis
Biochemical reactions
TSI:
IMVIC:
Urease:
Lipase:
DNAse:
Gelatinase:
MaConKey: Clear colonies (Lactose negative

Answer 8

A/A or K/A, H2S negative

• • • +

Negative

Positive

Positive

Positive

Question 9

Resembles Enterobacter but differentiated by its inability to ferment lactose, sucrose, sorbitol, and raffinose

Differentiated from Serratia because it is
DNAse and Lipase (-)

Answer 9

Hafnia alvei (Enterobacter alvei)

Question 10

– MAJOR CHARACTERISTICS OF Hafnia

Answer 10

Delayed positive citrate reaction

Question 11

Tribe Proteeae
General Characteristics
Comprised of the genera:

Answer 11

Proteus, Providencia, and Morganella (PPM)

Question 12

Widely distributed in the environment, are normal intestinal flora, and are recognized as opportunistic pathogens.

Answer 12

Tribe Proteeae

Question 13

Distinguished from other members of the Enterobacteriaceae by their ability to
deaminate phenylalanine deaminase (PAD +)

None of the members of this tribe ferment lactose

Answer 13

Proteus, Providencia, and Morganella (PPM)

Question 14

(2) are widelyrecognized human pathogens

Isolated from urine, wounds, ear, and blood

Responsible for 3% of UTI in the U.S
§ Ascend the urinary tract causing infections both in the lower and upper tracts

§ Can infect proximal kidney tubules and can cause acute glomerulonephritis particularly in patients with urinary tract defects or catheterization

Answer 14

Proteus mirabilis and Proteus vulgaris

Question 15

– lead to struvite kidney stones

Answer 15

Urease activity of Proteus

Question 16

easily identified by their
swarming colonies on culture media

Answer 16

Proteus mirabilis and Proteus vulgaris

Question 17

– thought to play a role in the ascending nature of Proteus-associated UTI

Answer 17

Swarming ability

Question 18

– produce a distinct “burnt chocolate” odor

Answer 18

Swarmers

Question 19

When different Proteus species swarm towards each other,
a line of inhibited growth results where strains meet.

Answer 19

Diene’s Phenomenon

Question 20

This line of inhibited growth results from the production of
and sensitivity to different types of bacteriocins, namely,
proticines, produced by different strains of Proteus species

Answer 20

Diene’s Phenomenon

Question 21

antigens are used in the diagnosis of rickettsial disease

are cross-reactive with Rickettsia antigens

Answer 21

Proteus

Question 22

Proteus antigens are used in the____– an agglutination test to differentiate rickettsial
disease.

Answer 22

Weil-Felix test

Question 23

are lactose-negative, deaminase (PAD) positive, H2S-negative, and motile

Characterized by a pungent odor

Ferment mannose, and do not swarm on SBA

Answer 23

Providencia species

Question 24

– the only urease positive providencia

Answer 24

Providencia rettgeri

Question 25

Providencia have been associated with human infections. Associated with nosocomial infections of the urinary tract and the skin

Answer 25

P.rettgeri and P.stuartii

Question 26

Providencia – associated with UTI in those with indwelling catheter

Answer 26

P. stuartii

Question 27

– only species within the genus Morganella

Answer 27

Morganella morganii

Question 28

Citrobacter Three species most often isolated from diarrheal stool cultures

Answer 28

§ Citrobacter koseri § Citrobacter braakii § Citrobacter freundii

Question 29

– associated with infectious diseases in hospital settings such as UTIs, pneumonias, and intra-abdominal abscess. It is also associated with endocarditis in IV drug abusers

Answer 29

Citrobacter freundii

Question 30

General Characteristics Motile, biochemically resembles Salmonella

Answer 30

Citrobacter

Question 31

Differentiated with Salmonella through: § Urea hydrolysis – 70% of C.freundii___ Salmonella are___ § LDC - all species of Citrobacter are___

Answer 31

(+); negative negative

Question 32

Edwardsiella General Characteristics Composed of three species:

Answer 32

E. tarda; E. hoshinae; E. ictaluri

Question 33

§ Isolated from cold blooded animals including reptiles, freshwater and aquarium fish, frogs, and turtles.

Answer 33

E. tarda; E. hoshinae; E. ictaluri

Question 34

Edwardsiella – the only recognized pathogen. § Opportunistic § Isolated in GI infections

Answer 34

E.tarda

Question 35

Edwardsiella All of them are____ for urea hydrolysis All of them are____ for: § Lysine decarboxylase § H2S, and indole All of them do not grow on____

Answer 35

negative positive Simmon’s citrata

Question 36

Plesiomonas General Characteristics Formerly under the family…

Answer 36

Vibrionaceae

Question 37

Oxidase-positive (take note that Enterobacteriaceae are oxidase negative!), glucose-fermenting, facultatively anaerobic, gram-negative bacilli Phylogenetically closely related to Enterobacteriaceae, but it does not have the ability to produce gas from glucose Only oxidase-positive member of the family Enterobacteriaceae

Answer 37

Plesiomonas

Question 38

Pleiiomonas – the only species in this genus.

Answer 38

Plesiomonas shigelloides

Question 39

– appear to have much lower virulence compared to Shigella spp. It has emerged as a potential cause of enteric disease in humans, most often after consumption of undercooked seafood or untreated water.

Answer 39

Plesiomonas shigelloides