Bordetella, Francisella, and Brucella

BORDETELLA:

• Extremely small
  
• Strictly aerobic
  
• Nonfermentative
  
• Gram-negative coccobacilli
  
• Non-motile
  
• Doesn't ferement CH, oxidizes amino-acids
  
• Nicotinamide required for growth
  
• B. pertussis doesn't grow on common media
  
• 3 species:
  
  • B. pertussis: pertussis
    
  • B. parapaertussis: pertussis
    
  • B. bronchiseptica: beonchopulmonary disease
    

FRANCISELLA TULARENSIS:

• Causes Tularemia(glandular fever, rabbit fever, tick fever, and deer fly fever)
  
• Very small, gram-negative coccobacilli
  
• Nonmotile
  
• Fastidious growth requirements: cysteine
  
• Striclty aerobic
  
• Intracellular parasite
  
• Most common reservoir in the US: rabbits, ticks, and muskrats
  
• Most common in MO, AR, and OK
  
• Summer and winter time +++
  
• Different presentations:
  
  • Ulceroglandular
    
  • Oculoglandular
    
  • Glandular
    
  • Typhoidal
    
  • Oropharyngeal
    
  • Pneumonic
    
  • Gastrointestinal
    
• Trt: Streptomycin
  

BRUCELLA:

• 4 causes human Brucellosis: B. abortus, B. melitensis, B. suis, and B. canis
  
• Small, non-motile, nonencapsulated, gram-negative coccobacilli
  
• Strictly aerobic
  
• Grows slowly

Pseudomonas and Related Organisms

• Opportunistic pathogens of plants, animals, and humans
  
• Non-fermentative bacilli
  
• P. aeruginosa
  
• Burkholderia cepacia
  
• Stenotrophomonas maltophilia
  
• Acinetobacter baumannii
  
• Moraxella catarrhalis
  

Pseudomonas:

• Opportunistic pathogen:
  
  • Immunocompromised
    
  • COPD, cystic fibrosis, bronchiectasis
    
  • Burn wounds
    
  • Trauma to eye
    
  • Exposure to contaminated water
    
  • Diabetic, and elderly
    
  • IV drug users
    
• Clinical syndromes:
  
  • Pulmonary infections
    
  • Skin infections
    
  • UTI
    
  • Ear infections: swimmer's ear and malignant external otitis
    
  • Eye infections
    
  • Bacteremia and Endocarditis may cause: ecthyma gangrenosum
    

  BURKHOLDERIA:
  

  • B. cepacia and B. pseudomallei: +++
    
  • B. pickettii:+
    
  • B. gladioli and mallei: are not pathogens
    
  • Commonly associated with nosocomial infections
    

    B. Cepacia: like Pseudomonas but different trt
    

  • Causes:
    
    • Respiratory infections (cystic fibrosis, chronic granulomatous disease)
      
    • UTI
      
    • Catheter related-Septicemia
      
    • Other opportunistics
      
    • P. cepacia is most susceptible to TMP/SMX eventhough other antibiotics may show in vitro activities(poor vivo response)
      

    B. pseudomallei:
    

    • Causes melioidosis
      
    • Rare in the WEST
      

STENOTROPHOMONAS MALTOPHILA:

• S. maltophilia
  
• Opportunistic pathogen
  
• Resistant to most commonly used beta-lactam and aminoglycosides
  
• Patients receiving long term antibiotic therapy at high risk
  
• May cause: bacteremia, pneumonia, meningitis, wound infections, UTI.
  
• Most active agent: TMX/SMX
  
• Other abx: chloramphenicol and ceftazidime.
  

ACINETOBACTER:

• A. baumannii
  

Campylobacter and Helicobacter

Vibrio, Aeromonas, Plesimonas

• Major group of gram-negative, facultative anaerobic
  
• Fermentative bacilli
  
• Difference from Enterobacteriacae:
  
  • Positive oxidase
    
  • Polar flagella
    

  
  

Vibrio Species Associated with human diseases
SPECIES	SOURCE OF INFECTION	CLINICAL DISEASE
V. cholerae	Water, food	Gastroenterits
V. parahaemolyticus	Shellfish, seawater	Gastroenterits, wound infection, cellulitis
V. vulnificus	Shellfish, seawater	Bacteremia, wound infection, cellulitis
V. alginoliyticus	Seawater	Wound infection, external otitis
V. hollisae	Shellfish	Gastroenterits, wound infection, bacteremia
V.fluvialis	Seafood	Gastroenterits, wound infection, bacteremia
V. damsela	Seawater	Wound infection
others

• Vibrio choleae:
  
  • Rice-water-stools
    
• Vibrio parahaemolyticus:
  
  • Explosive diarrhea
    
  • Cellulitis after exposure to seawater
    
• Vibrio vulnificus:
  
  • Particularly virulent
    
  • Rapidly progressive wound infections(seawater contamination)
    
  • Septicemia(raw oysters)
    
  • Most severe in patients with hepatic disease, hematopoietic disease, or CKD, immunosuppressive drugs.
    

• AEROMONAS:
  
  • A. hydrophila, A. caviae, and A. veronii
    
  • Ubiquitous in fresh and brackish water
    
  • Infection by ingestion of water or food
    
  • Opportunistic systemic diseases in immunocompromised patients(liver disease, cancer)
    
  • Chronic diarrhea in healthy adults-when severe may resembles shigellosis(invasive)
    
  • Resistant to PCN, Cephalo, Erythromycins.
    
  • Effective rx: TMP/SMX, Gentamicin, and chloramphenicol
    
• PLESIOMONAS:
  
  • Gram-negative bacilli
    
  • Oxidase positive
    
  • Multiple polar flagella
    
  • Difference from Aeromonas by biochemical reactions
    
  • P. Shigelloides
    
  • Fresh water and estuarine waters
    
  • Infection by contact with fresh water, consumption of seafood, or exposure to amphibians and reptiles.
    
  • Causes gastroenteritis
    
  • RESISTANT to ampicillin, erythromycin, and many aminoglycosides.
    
  • Susceptible to cephalosporins, imipenem, TMP/SMX, fluoroquinolones

Enterobacteriaceae

Neisseria

Listeria, Erysipelothrix, and other gram-positive bacilli

• Aerobic
  
• Gram-positive bacilli
  
• Resembles Corynebacterium organisms
  
• Including:
  
  • Listeria
    
  • Erysipelothrix
    
  • Arcanobacterium
    
  • Gardnerella
    
• LISTERIA:
  
  • Capable of causing meningitis and bacteremia
    
  • Small coccobacilli may resemble:
    
    • Corynebacteria
      
    • Gram positive diplococci(e.g., Strep pneumoniae,, enterococcus)
      
  • Characteristic tumbling motion
    
  • Attack specific populations:
    
    • Neonates
      
    • Elderly
      
    • Pregnant women
      
    • Immunocompromised (cell-mediated)
      
• Erysipelothrix
  
  • E. rhusiopathiae
    
  • Ubiquitous
    
  • Eryssipeloid is an occupational disease: swine and fish workers
    
  • Absence of motility and catalase difference between Listeria
    
• Arcanobacterium
  
  • A. haemolyticus
    
  • Causes pharyngitis with or without scarlet-like fever
    
• Gardnerella
  
  • G. vaginalis
    
  • Part of the normal vaginal flora
    
  • The number of Gardnerella and other obligate anerobes (Bacteroides, Mobiluncus, and peptostreptococcus) significantly increases in bacterial vaginosis