9.4

• MAC-positive, Oxidase-Negative

  Enterobacteriaceae<|>Acinetobacter<|>Streptophomonas
• Optimally recovered in special media
• Haemophilus


  Small pleomorphic rods or coccobacilli<|>Nonmotile<|>Facultative anaerobe<|>Capnophilic: 5-10% CO2<|>Oxidase-positive
• X factor

  Heat stable, derived from hemoglobin denaturation
• V factor

  Heat labile, can be supplied by yeast, potato extract, bacteria
• Must culture Haemophilus on CHOCOLATE AGAR!
• Porphyrin Test


  Test for X factor requirement<|>(-) if organism require X factor<|>(+) if organism don't require X factor
• Differential properties of Haemophilus species

  • V factor requirement
  • X factor requirement
  • D-ALA
  • Increased CO2 requirement
  • Hemolysis
• Haemophilus influenziae

  May be encapsulated (quellung reaction) or nonencapsulated<|>Unencapsulated strains: small, smooth, and translucent (dewdrop-like)<|>Encapsulated strains: larger, more mucoid colonies<|>Mousy (mouse nest) or bleachlike odor colonies<|>Colonies exhibit satellite phenomenon around S. aureus
• Inhalation of droplets (active cases, convalescent patients, carriers)
• Haemophilus influenziae

  Has 6 serotypes (a-f)<|>Serotype b: most common type associated with infection
• Diseases produced by Haemophilus influenziae

  • Acute bacterial epiglotittis
  • Acute bacterial meningitis (infancy and early childhood), Pneumonia, Septic arthritis
  • Otitis media, sinusitis, conjunctivitis
• Haemophilus influenziae biotype aegyptius

  Pink eye conjunctivitis (purulent)<|>Brazilian purpuric fever (severe; high mortality in children aging 1-4 years)
• Haemophilus ducreyi

  Smallest pathogenic bacteria!<|>Not part of normal human flora<|>High humidity<|>Special media required
• May occur intracellularly or extracellularly
• Chancroid


  Venereal disease (STD) characterized by painful ulcers in the genitalia<|>Caused by Haemophilus ducreyi
• Optimally recovered in special media

  • Bartonella
  • Hafnia
  • Campylobacter
  • Acrobacter
  • Helicobacter
  • Legionella
  • Brucella
  • Bordetella pertussis and B. parapertussis
  • Francisella
  • Streptobacillus moniliformis
  • Spirillum minus
• Bartonella

  Genus Bartonella has been removed from the order Rickettsiales<|>Cultivated in blood-enriched media in the presence of 5% carbon dioxide<|>Facultative intracellular gram-negative bacilli<|>Usually reside within erythrocytes in their natural mammalian hosts
• Bartonella bacilliformis

  Pleomorphic, motile, aerobic coccobacilli<|>Grows best @ RT<|>Grown in semisolid media containing fresh rabbit/horse or human blood<|>Colonies described as white puffs
• Bartonellosis

  Oroya fever: Severe febrile hemolytic anemia<|>Verruga peruana: Cutaneous (warts)<|>Transmitted by bite of sandfly (Phlebotomus)
• Bartonella henselae


  Causes "Cat scratch disease" (CSD)<|>Usually is self-limited<|>Lymph nodes become swollen<|>Fever, headache, fatigue, and a poor appetite<|>Rare complications are bacillary angiomatosis and Parinaud's oculoglandular syndrome
• Bartonella quintana

  Causes Trench fever<|>Transmitted by louse (Pediculus humanus corporis) feces laden with B. quintana<|>Manifestations include fever, generally lasting less than a week, headache, myalgias, pretibial pain, and an evanescent macular rash
• Laboratory Diagnosis of Bartonella

  • Culture
  • Serologic demonstration of antibodies
  • Smear preparation
• Hafnia

  Genus of Gram-negative, facultatively anaerobic, rod-shaped bacteria in the family Hafniaceae<|>H. alvei is a commensal of the human gastrointestinal tract and not normally pathogenic, but may cause disease in immunocompromised patients<|>Used as a lactic ferment by the dairy industry and more recently as a probiotic
• Campylobacter

  Upon gram staining, display a characteristic microscopic morphology as small, curved or seagull-winged, faintly staining, gram-negative rods<|>Polymerase chain reaction (PCR) amplification may provide an alternative to culture methods for detection<|>Several commercial antigen detection systems are available for the direct detection in stool specimens
• Media for Campylobacter

  • Campy-BAP
  • Campy medium (CVA)
  • Campylobacter agar base blood free (CCDA)
• Cultivation of Campylobacter from stool

  Successful isolation requires selective media and optimum incubation conditions<|>Recommended inoculation of two selective agars<|>Extended incubation may be required, 48 to 72 hours
• Helicobacter pylori


  Causes gastritis, peptic ulcer disease, and gastric cancer<|>Helical bacterium having a predominantly helical shape<|>Microaerophilic - requires oxygen, but at lower concentration than in the atmosphere<|>Contains a hydrogenase that can produce energy by oxidizing molecular hydrogen (H2)<|>Can be demonstrated in tissue by various stains<|>Capable of forming biofilms<|>Uses many different virulence factors including oxidase, catalase, and urease
• Viable but nonculturable (VBNC)

  State of microorganisms that are alive but cannot be cultured using standard microbiological techniques
• Helicobacter pylori

  Microaerophilic - requires oxygen, but at lower concentration than in the atmosphere<|>Contains a hydrogenase that can produce energy by oxidizing molecular hydrogen (H2) made by intestinal bacteria
• Demonstration of H. pylori in tissue

  1. Gram stain

  2. Giemsa stain

  3. H&E stain

  4. Warthin-Starry silver stain

  5. Acridine orange stain

  6. Phase-contrast microscopy
• Urease


  The most abundant protein in H. pylori, its expression representing about 10% of the total protein weight
• Major outer membrane protein families of H. pylori

  • Known and putative adhesins
  • Porins
  • Iron transporters
  • Flagellum-associated proteins
  • Proteins of unknown function
• The presence of VacA and CagA are associated with more advanced outcomes
• CagA


  An oncoprotein associated with the development of gastric cancer, a major virulence factor of H. pylori
• Legionella

  Non–spore-forming, faintly staining, thin, gram-negative bacilli
• Legionella was first recognized to cause human disease during an epidemic of pneumonia among members of the Pennsylvania American "Legion" who had gathered in Philadelphia (1976)
• Sources of Legionella infection

  • Natural - ponds, creeks, streams
  • Air conditioning cooling towers and heating systems
  • Water supplies of hospitals & hotels (tap water)
  • Hot showers (can survive up to 65°C)
• Growth within environmental protozoa is thought to be an important factor for survival of Legionella in the environment
• Human-to-human infection and laboratory-acquired infections with Legionella are not known to occur