This document provides information on Pasteurella multocida, including its characteristics, serotypes, epidemiology, pathogenesis, identification, and isolation. P. multocida was first found in 1878 infecting birds. It is a gram-negative, non-motile coccobacillus that resides normally in the nasopharynx of animals. Strains are classified into five serogroups and sixteen serotypes based on capsular and somatic antigens. Serogroups B and E are associated with hemorrhagic septicemia, a fatal disease of cattle and buffalo. Identification involves culturing the bacteria from infected tissues and running biochemical tests on colonies.

1. DR. AAMIR GHAFOOR BAJWA
ASSOCIATE PROFESSOR
DIRECTOR ,QUALITY OPERATION LABORATOR
DIRECTOR , UNIVERSITY DIAGNOSTIC LABOR

2. Pasteurella multocida
General charateristics:-
Family : Pasteurellaceae
Pasteurella multocida was first found in 1878 in cholera-infected
birds.
• Gram negative
• Non motile
• Penicillin sensitive
• Coccobacillus
• Facultative anaerobe
• Oxidase positive
• Catalase positive

3. •It grows on the blood agar or chocolate agar at 37 °C
•The recommended agar for Pasteurella multocida is Brain heart
infusion agar .
•It does not grow on the MacConkey agar.
• P. multocida is susceptible to mild heat (55°C)
•. Resides mostly as a commensal in the nasopharynx of animals.

4. Serotypes
Capsular and somatic serotypes:-
•Strains belonging to this specie are currently classified into
five serogroups (A, B, D, E, F) based on capsular antigen.
• And on the basis of lipopolysaccharide (LPS) antigens, it has
been divided into serotypes 1 to 16 .
• The strain of P. multocida which causes Hemorrhagic septicemia
(HS) belongs to serogroup B or E.

5. Epidemology
• Haemorrhagic septicaemia (HS) is a major disease of cattle and
buffaloes characterised by an acute, highly fatal septicaemia with high
morbidity and mortality
• In many Asian countries HS disease outbreaks mostly occur during
the climatic conditions typical of monsoon (high humidity and high
temperatures)

6. Epidemology
The Asian serotype B:2 and the African serotype E:2 , are mainly
responsible for the disease called haemorrhagic septicaemia
Other serotypes, namely A:1, A:3, have been associated with a
HS-like condition in cattle and buffaloes in India with mainly
pneumonia leading to death of the animal.
The letter denotes the
capsular antigen and the number stands for the somatic antigen.

7. Pathogenesis
In healthy and unstressed animals , it is commensal of respiratory tract
When defence system is compromised, initially the multiplication of the
organism occurs in the nasopharynx
Lungs are deluged with large number of bacteria
Depression, laboured breathing , oronasal discharge, swelling
Septicemia leading to respiratory distress

8. Pasteurella multocida causes the following diseases in different
species.

9. Identificaion and isolation of P. multocida
Pasteurella multocida is isolated, from visceral organs such as
lung, liver and spleen, bone marrow and nasal swabs .
• It is a facultative anaerobic bacterium that grows best at 37°C.
•The recommended media for growth of P. multocida is brain heart
infusion agar or broth .
•Pasteurella multocida does not cause haemolysis, is not motile
and does not grows on MacConkey agar.

10. • Colonies range from 1 to 3 mm in diameter after 18–24 hours of
incubation and are discrete circular, convex and translucent.
•The cells are coccobacillary or short rod-shaped, stain Gram
negative. Bipolar staining is evident with Giemsa stains

11. Identification of P. multocida is based on the results of biochemical
tests, which include carbohydrate fermentation, enzyme
production, and selected metabolite production.
fermented Non-fermented Positive test Negative test
glucose,
mannose,
galactose,
fructose, and
sucrose
Arabinose,
maltose, lactose,
cellobiose,
raffinose, inulin,
erythritol,adonito
l and m-inositol
catalase, oxidase,
ornithine
decarboxylase,
indole and
hydrogen
sulphide
methyl red,
Voges–Proskauer,
urease, lysine
decarboxylase,
beta
galactosidase, or
arginine
dihydrolase