Proteeae

Sharq Elneil College

School of Medical Laboratory

Sciences

Department of Microbiology

Medical Bacteriology course

U.Mahadi Hassan Mahmoud Bsc, Msc, MIBMS Microbiology

Proteus

Proteus The sub-family include:

Proteus.

P.mirabilis

P.vulgaris

Morganella. M.morgani

Providencia. P. rettgeri

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.

Morphology & stain

Gram negative bacilli, poleomorphic.

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.

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.

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).

Viability Easy to killed by heat.

Easy to killed by lab-

disinfectant.

Sensitive to most antimicrobial

agent used for

enterobacteriaceae.

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)

PPA TEST :

Left-hand tube exhibits a positive reaction(green).

Other tube is negative.

Antigenic structure Possess O- antigen (classification

& identification).

Possess H-antigen.

Do not possess K-antigen.

Pathogenicity Cause opportunistic infection.

UTI following catheter & surgery.

Wound infection.

Otitis media.

Septicemia (complication of UTI &

wound infection).

Pneumonia (very rare).

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.

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.

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.

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