Proteus are Gram-negative, motile bacilli that are commonly found in the environment and intestines. The two main species are P. mirabilis and P. vulgaris. They are characterized by swarming growth on agar plates and being positive for urease, motility, and H2S production. Proteus can cause opportunistic infections like UTIs and wound infections. Identification involves culture, biochemical tests, and Dienes phenomenon for differentiation of species. Antibiotics effective against Proteus include cephalosporins and aminoglycosides.

1. Sharq Elneil College
School of Medical Laboratory
Sciences
Department of Microbiology
Medical Bacteriology course
Proteeae
U.Mahadi Hassan Mahmoud
Bsc, Msc, MIBMS Microbiology

3. Proteus

4. Proteus
The sub-family include:
 Proteus.
P.mirabilis
P.vulgaris
 Morganella. M.morgani
 Providencia. P. rettgeri

5. General characters:
 Member of enterobacteriaceae.
 Saprophytes (life in water & soil).
 Some are commensal in human
intestine.
 Non-sporing.
 Non-capsulated.
The main 2 species:
• P. mirabilis.
• P. vulgaris.

6. Morphology & stain
Gram negative bacilli, poleomorphic.

7. Culture characters
 Non-fastidious.
 MacConkey agar: pale yellow colonies
(NLF), moderate in size, moist and low
convex.
 CLED: pale blue-green colonies (NLF).
 Blood agar & nutrient agar: grow and
produced swarming cover all the plate
(characteristic).
 Produced fishy smell.

9. Swarming in Proteus mirabilis. (B) Movement of a mass of cells
at the swarming periphery. (C) Characteristic colony morphology.
The pattern is produced by alternating cycles of differentiation,
movement, and consolidation.

12. How to prevent swarming
 Increase the agar concentration (from 1.2-
1.5% to 6%).
 CLED (electrolytes deficiency).
 To add chemicals: chloral hydrate, Na-
azide & paranitroglycerol.
 MacConkey agar (Bile salt).

13. Viability
Easy to killed by heat.
Easy to killed by lab-
disinfectant.
Sensitive to most antimicrobial
agent used for
enterobacteriaceae.

14. Biochemical reaction
 Urease test: +ve (with 4 hours).
 PPA test: +ve.
 Motility test: +ve.
 H2S production test: +ve.
 MR: +ve VP: -ve
 Ferment: glucose & maltose.
 Not ferment: lactose.
 Indole & Citrate test: vairable (P.
mirabilis –ve indole test)

16. PPA TEST :
Left-hand tube exhibits a positive reaction(green).
Other tube is negative.

17. Antigenic structure
 Possess O- antigen (classification
& identification).
 Possess H-antigen.
 Do not possess K-antigen.

18. Pathogenicity
 Cause opportunistic infection.
 UTI following catheter & surgery.
 Wound infection.
 Otitis media.
 Septicemia (complication of UTI &
wound infection).
 Pneumonia (very rare).

19. Dienes phenomenon
 Test used for identification of Proteus
& differentiation of species.
 If inoculate two strains of Proteus as
spot on non-inhibitory culture media
in different polar and after incubation;
if the strains are different, the
swarming will be separated by line
and if they are identical there is no
line of separation.
 This test help in epidemiology.

21. Weil-flex reaction
 There are cross reaction between
certain species of Proteus and
Rickettsia (which cause typhus fever &
it is grow only on Tissue culture).
 When treated pt serum of person
infected with typhus fever with Proteus
Ag from spp (OX19, OXK and OX2)
will give +ve reaction.

22. LAB- Diagnosis
 Specimen: according to the side of
infection ( Pus, swabs, blood, urine,
sputum……etc).
 Direct Gram stain (same specimen).
 Culture & incubation.
 Colonial morphology.
 Indirect Gram stain.
 Biochemical reaction.

23. Antimicrobial susceptibility
 Antibiotics with activity against P. mirabilis
include
 ampicillin cephalosporins and
aminoglycosides.
 Some strains of P. mirabilis are beta
lactamase producing and therefore
resistant to ampicillin.
 Proteus species are resistant to polymyxin
and nitrofurantoin