Fastidious GNB, Legionella, Neisseria, and Moraxella catarrhalis

What genera are included in the family Pasteurellaceae?

• Haemophilus

• Pasteurella

• Mannheimia

• Actinobacillus

• Aggregetibacter

Characteristics of Pasteurellaceae

• Gram-negative coccobacilli; some pleomorphic

• Nonmotile

• Fastidious facultative anaerobes

HACEK group

• Haemophilus parainfluenzae

• Aggregetibacter

• Cardiobacterium

• Eikinella

• Kingella

Require CO2

Haemophilus spp.

• Requires growth factors X (hemin) and V (NAD); one or both

• 3-5% CO2 for growth

• Horse blood agar (HBA) isolates, differentiates species, and detects satellitism

• Serotype B is the most pathogenic

• Capsular antigen

• “School of fish” or “railroad track” appearance on gram stain

ALA-Porphyrin test

( + ): pink fluorescence under UV

• can synthesize heme/factor X; does not need to be supplied with it

( - ): no fluorescence

• requirement for factor X for growth

Haemophilus influenzae

ALA ( - )

Requires: FX, FV, FXV

Common cause of meningitis in children before vaccine

Haemophilus ducreyi

ALA ( - )

Requires: FX, FXV

Causes chancroids

Haemophilus haemolyticus

ALA ( - )

Requires: FX, FV, FXV

Hemolysis on HBA ( + )

Haemophilus parahaemolyticus

ALA ( + ); FX ( - )

Requires: FV or FXV

Hemolysis on HBA ( + )

Aggregatibacter spp.

• A. aphrophilus

• A. segnis

• A. actinomycetemcomitans

Normal mouth flora; potentially can cause endocarditis

No hemolysis on SBA

Does not require FX

Cardiobacterium spp.

• C. hominis

• C. valvarum

• Suttonella indologenes

Normal respiratory flora; exclusively causes endocarditis

Swollen, teardrop or dumbbell cells

Slow growing

Cardiobacterium hominis

SBA: gamma

Oxidase ( + )

Catalase ( - )

Denitrification ( + )

Indole ( + )

Eikenella corrodens

SBA: gamma

Oxidase ( + )

Catalase ( - )

Nitrogen reduction ( + )

Ornithine ( + )

• Related to Neisseria spp.

• Normal oral flora

• Infection from “fight bites”; cause of subcutaneous abscesses, cellulitis, bacteremia, osteomyelitis

• Bleach-like odor

Kingella kingae

SBA: beta

Oxidase ( + )

Catalase ( - )

Denitrification ( + )

• Normal upper respiratory and genitourinary flora

• Infection in upper respiratory and bones and joints of infants and children

• Portal of entry through breaches in the oropharyngeal mucosa

• Rare bacteremia and endocarditis

• Penicillin and cephalosporin susceptible

Capnocytophaga spp.

• Facultative, capnophilic

• Fusiform gram-negative bacilli with pointed ends

• Isolated from the human oropharynx and female genital tract

• Associated with dog bites and close contact (C. canimorsus)

  • Can cause head, neck, and CNS infections

  • Endocarditis, osteomyelitis, lung abscess

• Ampicillin susceptible

Streptobacillus moniliformis

• Infectious to rodents, koalas, turkeys, monkeys, and humans

• Animal laboratory workers or people living in rat-infested urban areas most at risk

  • Rat-bite fever: maculopapular rash, petechiae, joint pain, arthritis

  • Haverhill fever: transmitted by ingestion

Pasteurella and Mannheimia spp.

• P. dogmatis

• P. canis

• P. stomatis

• P. pneumotropica

  • Associated with bites and scratches from dogs and cats

• Mannheimia spp.

  • Domestic animal related

  • Shipping fever: herd overcrowding, respiratory tract infection

Pasteurella multocida

Gram-negative coccobacillus, no growth on MAC

Oxidase ( + )

Indole ( ++ )

• Common in oral cavities of domesticated and farm animals

• Wound infections and cellulitis in humans

  • Bone, joint, respiratory tract, CNS, and eye infections

  • Endocarditis, bacteremia, sepsis

  • Gynecologic and UTI

Acintobacillus spp.

22 species and unnamed taxa

A. ureae and A. hominis only have been isolated from human infections

• Bacteremia, endocarditis, meningitis, bone marrow infection, septic arthritis, pneumonia

Brucella spp.

Significant zoonosis: Brucellosis, undulant fever

• B. melitensis: causes chronic infection of the lymphatic system, granulomas

• Treated with doxycycline and gentamicin

High risk for lab-acquired infection

• Sniffing plates, working outside of BSC

ID:

• Slow growing, faintly staining, minute coccobacillus

• Patient has possible occupational exposure, traveled to endemic areas, or ingested raw meats or dairy

Franciella tularensis

Causes Tularemia; “rabbit fever”

• Several animal reservoirs

• Transmitted by ticks and deerflies, or direct contact with infected animal blood

• Aerosol transmission is also possible; potential for bioterrorism

• Ulceroglandular: 75%; painful lesions that develop into ulcers; location depends on point of entry

• Typhoidal: 25%; abrupt onset chills, fever, headache, sore throat, vomiting, abdominal pain, diarrhea

Small, pale staining coccobacillus

Culture requires cysteine enrichment; strictly aerobic

Dangerous to handle specimens in the lab; organism can penetrate through small breaks in skin

Treated with aminoglycoside streptomycin

Bartonella bacilliformis

Oroya fever (Carrion’s disease)

• Sand fly vector

• insidious or abrupt onset

Verruga peruana: cutaneous eruptive stage

Bartonella quintana

Trench fever

• Body lice vector

Bacillary angiomatosis

• Seen in immunocompromised

Bartonella henselae

Bacillary angiomatosis

• Seen in immunocompromised

Peliosis

• Cystic blood-filled lesions of the liver and spleen

• Associated with immunocompromised

Cat scratch disease

• Cat flea vector

• Transmitted from scratches

Bartonella clarridgeiae

Cat scratch disease

• Cat flea vector

• Transmitted from scratches

Bordetella spp.

B. pertussis

B. parapertussis

B. bronchiseptica

Bordetella pertussis

Isolated on Bordet-Gengou (potato-blood-glycerol) agar

• Mercury droplet appearance

Regan and Lowe agar

• Horse blood and charcoal

Virulence

• Pertussis toxin: peripheral lymphocytosis

• Tracheal cytotoxin: paralyzes ciliated epithelial cells; leads to distinctive cough

Legionella spp.

Gram-negative bacilli; short to longer filamentous forms

• Stain better with Diff-Quik, Giemsa, or Gram-Weigert stains

• Poorly stain with safranin; basic fuchsin is optimal

Grown on BCYE agar (buffered charcoal yeast), supplemented with cysteine

• May form crystalline structures

85% of cases usually the result of L. pneumophila

Legionnaires’ disease

• 15-30% mortality

• 2-10 day incubation

• Pneumonia, renal failure, diarrhea, delirium, confusion

• Usually occurs in middle-aged to older people

Pontiac fever

• 0% mortality

• 1-2 day incubation

• Flu-like symptoms

• Mild respiratory illness

What is the most effective test for Legionellosis?

Urinary antigen test: uses antibodies against L. pneumophila subgroup 1 antigens

• Combined with clinical history

Histochemical stains used to detect Legionella

• Warthin-Starry

• Dieterle

• Steiner

Neisseria spp.

Capnophilic, gram-negatve diplococci; coffee bean appearance

Inhabit mucous membranes; grow best at 35-37C

Oxidase ( + )

Catalase ( + ); superoxol (30% H2O2)

Virulence

• Polysaccharide capsule

• IgA protease

• Iron-releasing enzymes

MTM selective media

• Contains vancomycin, colistin, trimethoprim, nystatin, amphotericin-B, and anisomyin

Neisseria gonorrhoeae

• CTA: glucose ( + )

• Coagglutination with S. aureus

• Stuart’s or Amie’s semisolid transport media

• Infection in endocervix can lead to PID

  • Rare disseminated gonococcal infection

  • Ocular infection in neonates

  • Definitive diagnosis in males

Neisseria meningitidis

• CTA: glucose, maltose ( + )

• Polysaccharide capsule is major virulence factor

• High transmission rates; can be asymptomatically carried

• Large cause of community acquired meningitis among young adults

  • Purpura fulminans

  • Waterhouse-Friderichsen syndrome: hemorrhage of adrenal glands

• Vaccine available; oral rifampin or penicillin G for treatment

Neisseria lactamica

• CTA: glucose, maltose, lactose ( + )

• May act as natural immunogen against N. meningitidis

Neisseria sicca

• CTA: fructose ( + )

• May cause endocarditis

Moraxella catarrhalis

• “Hockey puck” movement on BA

• Oxidase ( + )

• Catalase ( + )

• Butyrate esterase ( + )

• DNAse ( + )

• B-lactamase ( + )

• Infections

  • Otitis media and sinusitis in children

  • Respiratory tract infection in older and immunocompromised

• Penicillin R