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Fe A. Bartolome, MD, DPASMAP Department of Microbiology & Parasitology Our Lady of Fatima University

Miscellaneous Bacteria. Fe A. Bartolome, MD, DPASMAP Department of Microbiology & Parasitology Our Lady of Fatima University. HAEMOPHILUS. Family Pasteurellaceae Small, gram negative, pleomorphic Require enriched media containing blood or its derivatives Facultative anaerobes

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Fe A. Bartolome, MD, DPASMAP Department of Microbiology & Parasitology Our Lady of Fatima University

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  1. Miscellaneous Bacteria Fe A. Bartolome, MD, DPASMAP Department of Microbiology & Parasitology Our Lady of Fatima University

  2. HAEMOPHILUS • Family Pasteurellaceae • Small, gram negative, pleomorphic • Require enriched media containing blood or its derivatives • Facultative anaerobes • Obligate parasites

  3. Haemophilus influenzae • Found on mucus membrane of URT in humans (noncapsular form)  encapsulated species uncommon members of normal flora • Short, coccoid bacilli in pairs or chains

  4. Haemophilus influenzae • Classification: • Serotype – based on capsular antigen • Biotype – based on biochemical properties • a. indole production • b. urease activity • c. ornithine decarboxylase activity • Biogroup – useful for clinical purposes

  5. Haemophilus influenzae Culture: • Chocolate agar – flat, grayish brown colonies after 24 hrs incubation • Does not grow on sheep blood agar except around colonies of Staphylococci  “satellite phenomenon”

  6. Haemophilus influenzae Growth Characteristics: • Requires X factor (hemin) and V factor (NAD) • Ferments carbohydrates poorly and irregularly

  7. Haemophilus influenzae Characteristics & Growth Requirements:

  8. Haemophilus influenzae Virulence Factors: • Capsule • Antiphagocytic; impair ciliary function • Main virulence factor • With capsular polysaccharides (a to f) • Type b – polyribose-ribitol phosphate (PRP)

  9. Haemophilus influenzae Virulence Factors: • Somatic antigen • Outer membrane proteins  lipooligo-saccharides (endotoxin) • IgA1 proteases

  10. Haemophilus influenzae Clinical Features: • H. influenzae type b • Most common serotype causing systemic disease • Meningitis • Pneumonia & empyemia • Epiglottitis • Cellulitis • Septic arthritis

  11. Haemophilus influenzae Clinical Features: • Non-typeable (non-encapsulated) H. influenzae • opportunistic • Chronic bronchitis • Otitis media • Sinusitis • Conjunctivitis

  12. Haemophilus influenzae Clinical Features: • Meningitis • 20 to bacteremic spread from nasopharynx • Peak incidence: 3 – 18 mos. Old • Epiglottitis • Cellulitis & swelling of supraglottic tissues • Pharyngitis, fever & dyspnea  complete airway obstruction  death

  13. Haemophilus influenzae Clinical Features: • Cellulitis • Reddish blue patches on cheeks or periorbital areas

  14. Haemophilus influenzae Clinical Features: • Arthritis • Infection of a single large joint • Children < 2 y/o or immunocompromised patients or those with previously damaged joints • Conjunctivitis • Epidemic and endemic • H. influenzae biogroup aegypticus

  15. Haemophilus influenzae Clinical Features: Sepsis with gangrene

  16. Haemophilus influenzae Prevention: • Chemoprophylaxis with Rifampin for non-immune children < 4 y/o who are close contacts • Hib conjugate vaccine • > 2 mos. Old  Hib conjugated with C. diphtheriae toxin protein or N. meningitidis outer membrane complex • > 15 mos. Old  Hib conjugated with diphtheria toxoid

  17. Haemophilus aegypticus • H. influenzae biotype III • Koch-Weeks bacillus • Resembles H. influenzae closely • Diseases: • Conjunctivitis – highly communicable • Brazilian purpuric fever – fever, purpura, shock and death

  18. Haemophilus ducreyi • Causes chancroid (soft chancre) • Ragged ulcer on genitalia with marked swelling and tenderness • Lymph nodes enlarged and painful • Organism grows best on chocolate agar incubated in 10% CO2 • No permanent immunity

  19. Haemophilus ducreyi

  20. Bordetella pertussis • Small, coccobacillary, encapsulated, gram (-) • With bipolar metachromatic granules (toluidine blue stain) • Non-motile; strict aerobe • Forms acid from glucose and lactose • Requires enriched media • Bordet-Gengou medium (potato-blood-glycerol agar) • Contains Pen G 0.5 ug/mL • Virulence genes – bvgA and bvgS

  21. Bordetella pertussis Gram stain Culture on chocolate agar

  22. Bordetella pertussis • Virulence Factors: • Filamentous hemagglutinin • Protein on pili; adhesion to ciliated epithelial cells • Pertussis toxin • a. promote lymphocytosis via inhibition of signal transduction by chemokine receptors  lymphocytes do not enter lymphoid tissues • b. promote sensitization to histamine • c. enhance insulin secretion • d. stimulate adenylate cyclase via ADP-ribosylation

  23. Bordetella pertussis • Virulence Factors: • Adenylyl cyclase toxin – inhibit phagocytosis • Tracheal cytotoxin • Fragment of bacterial peptidoglycan • Induce nitric oxide  destroy ciliated epithelium • Dermonecrotic toxin • Hemolysin

  24. Bordetella pertussis • Pathogenesis: • Adheres to and multiplies rapidly on epithelial surface of trachea and bronchi  interfere with ciliary action • No invasion of blood

  25. Bordetella pertussis • Clinical: • MOT: airborne droplets • Source of infection: patients in early catarrhal stage • Disease: Pertussis or Whooping Cough  acute tracheobronchitis • Incubation period: approx. 2 weeks

  26. Bordetella pertussis • Clinical: Stages of Disease • Catarrhal • Mild coughing and sneezing • Highly infectious but not very ill • Paroxysmal (1-4 weeks) • Series of hacking coughs, accompanied by copious amts. of mucus, ending with inspiratory “whoop”  exhaustion, vomiting, cyanosis and convulsions • High wbc count (16,000-30,000/uL) with absolute lymphocytosis • Convalescence - slow

  27. Bordetella pertussis • Laboratory Diagnosis: • Specimen: saline nasal wash (preferred) or nasopharyngeal swab • Direct fluorescence antibody test – 50% sensitivity • Culture of saline nasal wash fluid • PCR – most sensitive • Serology – (+) only on third week of illness  of little diagnostic value

  28. Bordetella pertussis • First defense is antibody that prevents attachment • Recovery from disease or immunization is followed by immunity • Second infection may occur but is mild • Re-infection occurring years later in adults may be severe • Vaccine-induced immunity not completely protective

  29. Bordetella pertussis • Prevention: • Chemoprophylaxis – Erythromycin  for exposed, unimmunized individuals OR exposed, immunized children < 4 years old • Vaccine – two vaccines available: • a. acellular vaccine – contains 5 purified antigens  main immunogen is inactivated pertussis toxin; first vaccine to contain a genetically inactivated toxoid  ADP-ribosylating activity removed • b. DPT x 3 doses

  30. BRUCELLA • Zoonotic  obligate parasite of animals & humans • Intracellular organism • Gram negative coccobacilli • Aerobic; non-motile; nonspore-forming • Catalase (+); oxidase (+) • Produces H2S • Culture: trypticase soy agar OR blood culture media; B. abortus requires 5-10% CO2 for growth

  31. BRUCELLA • Route of infection in humans: • Intestinal tract – ingestion of infected milk & contaminated dairy products (cheese from unpasteurized goat’s milk) • Mucous membranes – droplets • Skin – contact with infected tissues of animals • Pathogenesis: endotoxin – O antigen polysaccharide

  32. BRUCELLA

  33. BRUCELLA • Clinical: Brucellosis (Undulant or Malta Fever) • Acute • Malaise, fever, weakness, aches & sweats • Fever rises in the afternoon  fall during the night with drenching sweats • (+) lymphadenopathy w/ palpable spleen; + hepatitis with jaundice • Chronic • With psychoneurotic symptoms • Weakness, aches & pains, low grade fever

  34. BRUCELLA • Diagnosis: • Culture • BM & blood – commonly used specimen • Brucella agar, trypticase soy medium, brain heart infusion medium, chocolate agar • Serology – inc. IgM during 1st week of illness; peak at 3 months

  35. Francisella tularensis • Small, gram (-) pleomorphic rod • Widely found in animal reservoirs (rabbits, deer, rodents) • Humans are accidental “dead-end” hosts • Two biotypes: • Jellison type A – more virulent ; US • Jellison type B – less virulent ; Europe • Culture: glucose cysteine blood agar OR glucose blood agar

  36. Francisella tularensis Gram stain F. tularensis colonies on agar plate

  37. Francisella tularensis • Mode of transmission: • Contact with animal tissue • Bite of vector (Dermacentor tick) • Ingestion of infected meat • Inhalation • Symptoms caused by endotoxin

  38. Francisella tularensis • Clinical: • Ulceroglandular – 75%; ulceration at site of entry with swollen & painful LN • Glandular • Oculoglandular • Typhoidal • GI & pulmonary • Disease confers lifelong immunity

  39. Francisella tularensis Cutaneous tularemia

  40. Francisella tularensis • Diagnosis: culture not done due to high risk to lab workers • Agglutination test – most frequently used • Fluorescent antibody staining of infected tissue • Treatment: Streptomycin (DOC) • Prevention: live, attenuated vaccine – partial immunity; not available commercially

  41. YERSINIA • Short, pleiomorphic gram (-) rods with bipolar staining • Catalase and oxidase (+) • Microaerophilic or facultative anaerobe • All with LPS that have endotoxic activity

  42. Yersinia pestis • Non-motile, facultative anaerobe • Growth more rapid in media containing blood or tissue fluids at 300C  gray and viscous colonies

  43. Yersinia pestis • Virulence Factors: • LPS – endotoxin • Envelope – with protein (fraction I)  antiphagocytic • Coagulase • V-W antigens (virulent, wild type) – essential for virulence • Pesticin - bacteriocin

  44. Yersinia pestis • Pathogenesis: • Bite of vector (Xenopsylla cheopis)  organism phagocytosed by PMNs & monocytes  multiply in monocytes  lymphatics  (+) intense hemorrhagic inflammation in enlarged LN  bloodstream  hemorrhagic & necrotic lesions in all organs • Inhalation of infective droplets from coughing patients  primary pneumonic plague with hemorrhagic consolidation, sepsis and death

  45. Yersinia pestis • Clinical: Plague • I.P.: 2 – 7 days • High fever & painful lymphadenopathy (buboes) • Vomiting & diarrhea may develop with early sepsis • Later  DIC  hypotension, altered mental status, renal and cardiac failure • Terminal: signs of pneumonia & meningitis

  46. Bubo on neck Septicemic plague Yersinia pestis

  47. Yersinia pestis • Diagnosis: • Smear – Giemsa stain or Wayson’s stain (+ bipolar appearance) • Culture – blood agar or MacConkey’s agar plates; infusion broth; all cultures highly infectious • Serology - examination of acute and convalescent sera for antibody levels • Treatment: Streptomycin (DOC)

  48. Pasteurella multocida • Primarily animal pathogens • Non-motile gram (-) coccobacilli with bipolar appearance on stained smears • Occurs worldwide in respiratory tract and GIT of many domestic and wild animals • Most common organism in human wounds inflicted by bites from cats and dogs • Virulence factors include capsule and endotoxin

  49. Pasteurella multocida • Clinical: • Rapidly spreading cellulitis at site of animal bite • Incubation period < 24 hours • May present as bacteremia or chronic respiratory infection • Complication: osteomyelitis (cat bites) • Treatment: Penicillin G (DOC)

  50. Culture P. multocida infection Bacteremic P. multocida cellulitis Pasteurella multocida

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