This document provides information on the bacteria Proteus, including its characteristics, virulence factors, infections it causes, identification and treatment. It notes that Proteus is a gram-negative, motile bacillus that is commonly found in the intestines and can cause urinary tract and nosocomial infections. Its main virulence factors include urease production, which allows it to colonize the urinary tract, and fimbriae, which aid in attachment and colonization. Identification involves culturing on media like blood agar where it displays swarming motility and testing for properties such as being urease positive and oxidase negative. Treatment involves antibiotics like beta-lactams, aminoglycosides

1. Maneesha M Joseph
Assistant Professor
Baby Memorial College
Kozhikode
Video Class uploaded inYOUTUBE channel – MALLU MEDICOS LOUNGE

3. PROTEUS
Ø Member of enterobacteriaceae
Ø Gram negative bacteria
Ø Short bacilli
Ø Motile they have penitrichous flagella
Ø Non capsulated,Non sporing
Ø Urease positive
Ø Fishy odor
Ø Nitrates are reduced to nitrites
Ø Ferments glucose but does not ferment lactose
Ø Deaminates phenylalanine to phenylpyruvic acid

4. The word ‘Proteus’was derived from Greek
mythology, which described ‘Proteus’as an early
sea-god, noted for being versatile and capable of
assuming many different
forms. Plemorphic nature of this organism and
its rapid swarming motility might have
persuaded its discoverer Gustav Hauser to
rename it as Proteus.

5. v They are widely distributed in nature
and also occur as normal intestinal
flora of humans.
v An opportunistic pathogen, they are
one of the common cause of urinary
tract infections (UTIs) and are
associated with infection-induced renal
stones.
v Other infections caused by Proteus
species are pyogenic lesions, infection
of ear, respiratory tract infections and
nosocomial infections.

6. MAIN SPECIES OF MEDICAL
IMPORTANCE:
• P.mirabilis causes urinary tract infections (UIT)
• P.vulgaris causes nosocomial infections

7. VIRULENCE FACTORS
• Urease
• Hemolysins
• Motility & Swarming
• Flagella & fimbriae
• Proteinase

8. 1. UREASE
• Is a critical virulence determinant for colonization of the urinary tract ,stone
formation & the development of acute pyelonephritis
• Urease –induced formation of ammonia protects the bacterial cell from the
effects of complements
• => causes rapid hydrolysis of urea with liberation of ammonia . Thus, in
urinary tract infections with Proteus, the urine becomes alkaline ,promoting
stone formation.
2.FIMBRIAE
• Also play a significant role in virulence for the urinary tract also have a role in
the colonization of the upper part of the urinary tract
• Their presence correlates with the development of acute pyelonephritis

9. 3.HEMOLYSINS
• Also known to be important virulence factor of proteus spp.
• Both HpmA & HlyA are cytotoxic for a wide variety of cell types ,
together with urease they play an important role in cell invasion
& internalization
• Hemolysins and urease are expressed at higher levels in P. mirabilis
than in P.vulgaris and this may be the explanation for the greater
virulence o.f P.mirabilis

10. 4.PROTEINASE
Play a role in :
Ø-Degrading antibacterial peptides in the innate defense
system
Ø-Generating products like glutamine to induce invasive
swarm cell

11. ANTIGENIC CHARACTERISTICS
v The bacilli possess thermostable, ‘O’ (somatic) and thermostable ‘H’
(flagellar) antigens, based upon which several serotypes have been
recognized.
v Certain strains of Proteus vulgaris(OX-19, OX-2 ) and proteus mirabilis
(OX-K) produce O antigens that are shared by some rickettsiae.
v These Proteus strains are used in an agglutination test (the Weil-Felix test)
for serum antibodies produced against rickettsiae of the typhus and spotted
fever groups.

12. PATHOPHYSIOLOGY
• The first step in the infectious process is adherence of the microbe to host
tissue. Fimbriae facilitate adherence and thus enhance the capacity of the
organism to produce disease.
• Fimbriae are tiny projections on the surface of the bacterium. Specific
chemicals located on the tips of pili enable organisms to attach to selected
host tissue sites (eg, urinary tract endothelium).
• The presence of these fimbriae has been demonstrated to be important for the
attachment of P mirabilis to host tissue.

13. • The ability of Proteus organisms to produce urease and to alkalinize the
urine by hydrolyzing urea to ammonia makes it effective in producing
an environment in which it can survive. This leads to precipitation of
organic and inorganic compounds, which leads to struvite stone
formation.
• Struvite(Mineral produced by bacteria) stone formation can be
sustained only when ammonia production is increased and the urine pH
is elevated to decrease the solubility of phosphate.
• . Urease metabolizes urea into ammonia and carbon dioxide
Urea → 2NH3 + CO2

14. PROTEUS INFECTION
UTI Which progresses to :-
• Urethritis-infection of urethra
• Cystitis-inflammation of bladder
• Pyelonephritis -can be considered a progression of disease
& symptoms are therefore more profound
Symptoms of pyelonephritis include :
flank pain , nausea & vomiting ,fever , costo vertebral angle
tenderness, hematuria & pyuria are frequently encountered.

15. Laboratory Diagnosis & Identification
vThe sample used for the isolation and identification of the
Proteus species depends on the nature of the disease/site of
infections.
vFor UTI, midstream urine sample is used.
vFor pyogenic lesions, its the pus aspirate.
vSample should be collected in the sterile container
maintaining aseptic conditions and should reach laboratory
within an hour of collections.

16. CULTURE CHARACTERISTIC
ØBlood Agar
P.mirabilis and P.vulgaris => does not form distinctive
colonies on blood agar ,instead the bacteria swarm across the surface
of the agar
Swarming is described as the formation of concentric zonesof
bacterial growth , able to cover the whole surface of solid culture medium
as a consequence of the organisms active motility

17. SWARMING PHENOMENON

18. ANTI-SWARMING AGENTS
• This will physically restrict the movement of proteus cells By:
• 1- Increasing the agar concentration to 3-4% w/v
• 2- Affecting the flagella through incorporation with ethanol 5.5% ,
Boric acid 0.1% , detergents, bile salts etc..
• Retarding the cell growth rate by incorprtaing with growth inhibitors
such as sulfonamide ,purine bases, neomycin, sodium azide or chloral
hydrite.
• Activated charcoal inhibit swarming without affecting motility

19. Dienes phenomenon
v when two identical Proteus cultures are inoculated at different
points on the same plate of non-inhibitory medium, the
resulting swarming of growth coalesce without signs of
demarcation.[
v When, however, two different strains of Proteus are inoculated, the
spreading films of growth fail to coalesce and remain separated by
a narrow easily visible area.
v The observation of this appearance, the Dienes phenomenon has
been used to determine the identity or non-identity of strains
in epidemiological studies.

22. ØMacconkey Agar
Proteus does not ferment lactose so
acid is not produced and indicator will
not change color to pink
organisms appears as colorless
colonies
(non lactose fermenter)

23. PROTEUS IS UREASE POSITIVE

24. PROTEUS ONTSI AGAR
ALKALINE SLANT, ACIDIC BUTT, GAS POITIVE,
H2S POSITIVE

25. INDOLE TEST:
P. mirabilis can be differentiad
from P. vulgaris by INDOLE Test
Results:
P. mirabilis => Negative
P. vulgaris => Positive

26. OXIDASE TEST
• The oxidase test is used to determine if a
bacterium produces cytochrome c oxidases.
The reagent turns dark blue when
oxidized (oxidase positive) . The reagent is
colorless when reduced when reduced(
oxidase negative )
Proteus species is oxidase
negative = > colorless

27. PPA TEST
Phenylalanine deaminase test also known as phenyl pyruvic acid (PPA)
test is used to test the ability of an organism to produce enzyme
deaminase.
This enzyme removes the amine group from the amino acid
phenylalanine and produces phenyl pyruvic acid (PPA) and ammonia
i.e. oxidative deamination of phenylalanine.
Phenyl pyruvic acid reacts with ferric iron (10% ferric chloride is added
in the medium) producing a visible green colour.

29. Properties Proteus mirabilis Proteus vulgaris
Colony characteristics in
MacConkey Agar
Pale or colourless (NLF)
colonies
Pale or colourless (NLF)
colonies
Motility Swarming motility Swarming motility
Lactose fermentation No No
Indole production No Yes
Urease production Yes Yes
H2S production Yes Yes

30. TREATMENT
• PROTEUS is sensitive to these antibiotics :
• beta-lactame except penicillin G & oxacillin
• aminoglycoside , ceftriaxone ,
fluoroquinolones , & trimethoprim-
sulfamethoxazole that can be used as a
treatment for most proteus infection.