Characterization of Pasteurella multocida strains isolated from human infections

1. Proyecto de ciencias
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Mateo Duque Gallego
Tercer Semestre 2019-2
Facultad de Medicina
Universidad Pontificia Bolivariana

2. INTRODUCTION
the pasteurella multocida is an immobile facultative gram-negative pleomorphic
cocobacillus and can be classified into five capsular serogroups
(A, B, D, E and F)
Humans acquire Pasteurella
infection primarily from injuries
caused by companion animals.

3. P. multocida colonizes the gastrointestinal and respiratory tract of
a large variety of mammals and birds, which constitute its main
reservoir.
The most animals frequently colonized are
cats (50-90%) and dogs (50-65%)
Licks on skin
abrasions
• joint infections
• abscess
formation
• Cellulitis
• Meningitis
• lymphangitis
• Endocarditis
• Peritonitis
• Pneumonia
• sepsis
Animal bites
Scratches
P. multocida is the most prevalent species of the Pasteurella genus causing human infections

4. Objective
The detailed investigation of 15 Pasteurella
multocida clinical isolates obtained from
human infections in Hungary in
comparison with five cat-derived strains
of Pasteurella multocida.

5. MATERIALS & METHODS
Bacterial isolates and identification
15 5
Szent-Györgyi Albert
Medical and
Pharmaceutical Center
Their identity confirmed by a species specific PCR assay
represented various
geographic without any
connection to the human
cases
5% sheep blood
aerobic conditions
37 °C 24 h
Columbia
agar

6. PCR
• The polymerase chain reaction, technique
for making copies of a particular region of
DNA in vitro
• thermostable DNA polymerase
• DNA primers designed specifically for the
region of interest.
Fundament
• Identity confirmed by a species specific PCR
assay, Combinations of oligonucleotide primers
were used for amplification of
• kmt1 (species identification)
• ToxA (P. multocida toxin)
• hyaC-hyaD (capsular serogroup A)
Utility

7. (Restriction Fragment Length Polymorphism)
RFLP
Fundament
It refers to specific sequences of
nucleotides in DNA that are recognized
and cut by restriction enzymes
(restriction endonucleases)
Utility
Determinate the main
phylogenetic lineages
of P multocida
• FastDiges HindIII
restriction
endonuclease
• Agarose gel
• Electrophoresis and
images were
recorded using
Kodak Molecular
Imaging Software

8. Antimicrobial resistance
MIC
Quality control strain
Escherichia coli
ATCC 25922
Susceptibility test to 14
antimicrobial agents
It is the lowest concentration
of an antimicrobial that
inhibits the growth of a
microorganism.
important in laboratory
diagnoses to confirm the
resistance of microorganisms
in an antimicrobial agent and
also to monitor the activity
of new antimicrobial agents.
Minimal Inhibitory Concentration

9. RESULTS
The species-specific PCR confirmed the identity of all isolates of
P. multocida used in this study
hsf1 (654 bp)
2 4 6
hsf2 (433 bp)
2 3 4 6
PfhA (286 bp)
4 5
Autotransporter adhesins
Filamentous haemagglutinin

10. The toxA gene was not detected in any of the
isolates.
Type I fimbrial
subunits
fimA(866 bp)
tight adherence
protein D
tadD(416 bp)
2 3 4
6
5
4 5

11. All isolates from cats were of capsular type A
hgbA(402 bp)
nanH(340 bp)
1 2 3 4 65
1 2 3 4 5
Iron acquisition
proteins
Neuraminidase gene

12. The capsule biosynthesis gene fcbD (serogroup F)
was found in only one case
tbpA (728 bp)
632
Iron
acquisition
proteins

13. negativecontrol
+controlptfA(A)
+controlptfA(B)
Pm242
Pm243
Pm244
Pm247
Pm249
None of the isolates harboured bcbD (serogroup B),
dcbF (serogroup D) or ecbJ (serogroup E) genes.

14. Septica strains formed
a distinct phylogenetic
group with high
bootstrap support
values within the
species P. multocida
regardless of the host
species.
DENDROGRAM
ST333, ST334 and ST336
The P. multocida subsp. septica
strains were shown to be closely
related phylogenetically.

15. DISCUSSION
AUTHOR CONTRIBUTION
Holst et al. identified P. multocida subsp as the most
commonly recovered subspecies from infected
humans.
Chen et al. the majority of the strains recovered from
respiratory infections in humans were P.
multocida subsp multocida, while P. multocida
subsp septica strains dominated isolates from
wound infections.
Donnio et al. P. multocida subsp multocida was the most
common subspecies (87.5%) equally occurring
in both wound infections and respiratory tract
infections.
Ewers et al. described a similar virulence gene pattern to
that we found to be characteristic of P.
multocida subsp. septica strains.

16. CONCLUSIONS
Domestic animals are an
important reservoir of
Pasteurella multocida and
permanent contact with them
increases the risk of infection.
Type A was the most
prevalent capsular type
detected among the human
clinical isolates (14/15
strains)