Serratia Flashcards
Pigment production at room temperature. “Prodigiosin” – pink-to-red in color
§ Serratia marcescens
§ Serratia rubidea
§ Serratia plymuthica
– emits a dirty, musty odor resembling “rotten potatoes”
Serratia odorifera
Serratia are all
Sucrose fermenters
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.
Serratia fonticola
– 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.
Serratia marcescens
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
§ S.odorifera biogroup 1
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
§ S.odorifera biogroup 2
Serratia marcescens
Laboratory Diagnosis
Biochemical reactions
TSI:
IMVIC:
Urease:
Lipase:
DNAse:
Gelatinase:
MaConKey: Clear colonies (Lactose negative
A/A or K/A, H2S negative
- +
Negative
Positive
Positive
Positive
Resembles Enterobacter but differentiated by its inability to ferment lactose, sucrose, sorbitol, and raffinose
Differentiated from Serratia because it is
DNAse and Lipase (-)
Hafnia alvei (Enterobacter alvei)
– MAJOR CHARACTERISTICS OF Hafnia
Delayed positive citrate reaction
Tribe Proteeae
General Characteristics
Comprised of the genera:
Proteus, Providencia, and Morganella (PPM)
Widely distributed in the environment, are normal intestinal flora, and are recognized as opportunistic pathogens.
Tribe Proteeae
Distinguished from other members of the Enterobacteriaceae by their ability to
deaminate phenylalanine deaminase (PAD +)
None of the members of this tribe ferment lactose
Proteus, Providencia, and Morganella (PPM)
(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
Proteus mirabilis and Proteus vulgaris
– lead to struvite kidney stones
Urease activity of Proteus
easily identified by their
swarming colonies on culture media
Proteus mirabilis and Proteus vulgaris
– thought to play a role in the ascending nature of Proteus-associated UTI
Swarming ability
– produce a distinct “burnt chocolate” odor
Swarmers
When different Proteus species swarm towards each other,
a line of inhibited growth results where strains meet.
Diene’s Phenomenon
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
Diene’s Phenomenon
antigens are used in the diagnosis of rickettsial disease
are cross-reactive with Rickettsia antigens
Proteus
Proteus antigens are used in the____– an agglutination test to differentiate rickettsial
disease.
Weil-Felix test
are lactose-negative, deaminase (PAD) positive, H2S-negative, and motile
Characterized by a pungent odor
Ferment mannose, and do not swarm on SBA
Providencia species
– the only urease positive providencia
Providencia rettgeri
Providencia
have been associated with human infections.
Associated with nosocomial infections of the urinary tract and the skin
P.rettgeri and P.stuartii
Providencia
– associated with UTI in those with indwelling catheter
P. stuartii
– only species within the genus Morganella
Morganella morganii
Citrobacter
Three species most often isolated from diarrheal stool cultures
§ Citrobacter koseri
§ Citrobacter braakii
§ Citrobacter freundii
– 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
Citrobacter freundii
General Characteristics
Motile, biochemically resembles Salmonella
Citrobacter
Differentiated with Salmonella through:
§ Urea hydrolysis – 70% of C.freundii___
Salmonella are___
§ LDC - all species of Citrobacter are___
(+); negative
negative
Edwardsiella
General Characteristics
Composed of three species:
E. tarda; E. hoshinae; E. ictaluri
§ Isolated from cold blooded animals
including reptiles, freshwater and
aquarium fish, frogs, and turtles.
E. tarda; E. hoshinae; E. ictaluri
Edwardsiella
– the only recognized pathogen.
§ Opportunistic
§ Isolated in GI infections
E.tarda
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____
negative
positive
Simmon’s
citrata
Plesiomonas
General Characteristics
Formerly under the family…
Vibrionaceae
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
Plesiomonas
Pleiiomonas
– the only species in this genus.
Plesiomonas shigelloides
– 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.
Plesiomonas shigelloides
