Pasteurellaceae

D

Haemophilus influenzae Haemophilus ducreyi

Oppurtunists:Haemophilus parainfluenzaeHaemophilus spp.

Pasteurella multocida Actinobacillus

actinomycetemcomitans

Human Pathogens

Pasteurellaceae General Overview

Taxonomic Confusion in Family Pasteurellaceae Three Genera:

•Haemophilus: Most Common in Human Disease•Actinobacillus•Pasteurella

Haemophilus Common Characteristics of Family

Small (0.2 x 0.3-2.0 mm) Gram-negative Nonmotile bacilliAerobic or facultatively anaerobicFastidious growth requirements

Pasteurellaceae Differential Characteristics

X factor = hemin (hematin)V factor = (NAD or NADP)

nicotinamide adenine dinucleotide

Haemophilus

Haemophilus General Overview Gram-negative bacilli liking blood (as per genus name)

Obligate Parasites of Man and Animals Major pathogens for which humans are natural hosts• Haemophilus influenzae

Acute pyogenic, normally invasive infectionsChronic infections with H. influenzae as 2o pathogen

• Haemophilus ducreyi True pathogen (i.e., not found in healthy individuals)STD; Soft chancre (chancroid)

Haemophilus Diseases

Haemophilus Infections

PRP = polyribitol phosphate

(see others in text)

Haemophilus Infections

(cont.)

NOTE: Polysaccharide PRP is weakly immunogenicPediatric immunity not mature for processing polysaccharide antigens until ~18 monthsConjugated Vaccine: PRP conjugated to protein carrier induces protective immunity (carriers may include: diphtheria toxoid, tetanus toxoid or meningococcal OMP)

Haemophilus influenzae Incidence

NOTE: Dramatic decrease in children <5 years; remains constant in older children

(per

100

,000

)

Haemophilus influenzae Diseases

Haemophilus ducreyi Incidence

Actinobacillus

Actinobacillus General Overview Slow-growing; Small; Gram-negative Bacilli Facultatively Anaerobic Require CO2 for growth on chocolate or blood agar

Three Species of Actinobacillus Associated with Human Disease

Actinobacillus actinomycetemcomitans is: Most serious pathogen of genusHyperadherent in vitro and on damaged heart valvesCommonly isolated with Actinomyces

-comitans is Latin for “accompanying”Normal oropharyngeal flora in 20% of healthy people

Actinobacillus Diseases

HumanJuvenile & adult Subacute

Pasteurella

Pasteurella General Overview Small; Gram-negative; Fermentative Pleomorphic

Coccobacilli

Facultatively Anaerobic Therefore infects sutured bites or scratches

Pasteurella multocida:Most common human pathogen Domestic pets serve as major reservoirCommensals in upper respiratory tract of dogs,cats,etc.Human infection often related to animal bites or scratches

or shared food (and you wondered why that lady was buying so much

cat food --- it’s cheaper!)

Pasteurella DIseases

Three Forms of Disease Localized cellulitis and lymphadenitis following

animal bite or scratch In patients with underlying lung dysfunction,

worsening of chronic pulmonary disease from aspiration of organisms colonizing patient’s oropharynx

Systemic infection in immunocompromisedLiver disease patients at highest risk

Pasteurella Diseases (cont.)

Animal scratch or

REVIEWof

Pasteurellaceae

Pasteurellaceae Differential Characteristics

X factor = hemin (hematin)V factor = (NAD or NADP)

nicotinamide adenine dinucleotide

REVIEW

Review of Haemophilus

Haemophilus General Overview Gram-negative bacilli liking blood (as per genus name)

Obligate Parasites of Man and Animals Major pathogens for which humans are natural hosts• Haemophilus influenzae

Acute pyogenic, normally invasive infectionsChronic infections with H. influenzae as 2o pathogen

• Haemophilus ducreyi True pathogen (i.e., not found in healthy individuals)STD; Soft chancre (chancroid)

REVIEW

Haemophilus Diseases

REVIEW

Haemophilus Infections

PRP = polyribitol phosphate

(see others in text)

REVIEW

Haemophilus Infections

(cont.)

NOTE: Polysaccharide PRP is weakly immunogenicPediatric immunity not mature for processing polysaccharide antigens until ~18 monthsConjugated Vaccine: PRP conjugated to protein carrier induces protective immunity (carriers may include: diphtheria toxoid, tetanus toxoid or meningococcal OMP)

REVIEW

Haemophilus influenzae Incidence(p

er 1

00,0

00)

NOTE: Dramatic decrease in children <5 years following use of PRP conjugated vaccine; Disease rate remains constant in older children

REVIEW

Haemophilus ducreyi Incidence

REVIEW

Review of Actinobacillus

Actinobacillus General Overview Slow-growing; Small; Gram-negative Bacilli Facultatively Anaerobic Require CO2 for growth on chocolate or blood agar

Three Species of Actinobacillus Associated with Human Disease

Actinobacillus actinomycetemcomitans is: Most serious pathogen of genusHyperadherent in vitro and on damaged heart valvesCommonly isolated with Actinomyces

-comitans is Latin for “accompanying”Normal oropharyngeal flora in 20% of healthy people

REVIEW

Actinobacillus Diseases

HumanJuvenile & adult Subacute

REVIEW

Review of Pasteurella

Pasteurella General Overview Small; Gram-negative; Fermentative Pleomorphic

Coccobacilli

Facultatively Anaerobic Therefore infects sutured bites or scratches

Pasteurella multocida:Most common human pathogen Domestic pets serve as major reservoirCommensals in upper respiratory tract of dogs,cats,etc.Human infection often related to animal bites or scratches

or shared food (and you wondered why that lady was buying so much

cat food --- it’s cheaper!)

REVIEW

Pasteurella DIseases

Three Forms of Disease Localized cellulitis and lymphadenitis following

animal bite or scratch In patients with underlying lung dysfunction,

worsening of chronic pulmonary disease from aspiration of organisms colonizing patient’s oropharynx

Systemic infection in immunocompromisedLiver disease patients at highest risk

REVIEW

Pasteurella Diseases (cont.)

Animal scratch or

REVIEW