1 / 33

Diagnostic microbiology lecture: 15 Bordetella pertussis Abed ElKader Elottol MSc. Microbiology

Diagnostic microbiology lecture: 15 Bordetella pertussis Abed ElKader Elottol MSc. Microbiology 2010. Disease: whooping cough ( Pertussis) Pertussis = Transmitted by the respiratory tract rout from early case and possibly via carriers.

randi
Download Presentation

Diagnostic microbiology lecture: 15 Bordetella pertussis Abed ElKader Elottol MSc. Microbiology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Diagnostic microbiologylecture: 15Bordetella pertussis Abed ElKader Elottol MSc. Microbiology 2010 Abed ElKader ElOttol

  2. Abed ElKader ElOttol

  3. Abed ElKader ElOttol

  4. Disease: whooping cough (Pertussis) • Pertussis = Transmitted by the respiratory tract rout from early case and possibly via carriers. • The organism adheres to and multiply rapidly on the surface of the epithelium in the trachea and bronchi and interfere with ciliary action . • Disintegrating organisms liberate a toxin that irritate surface cells, giving rise to catarrhal symptoms. Abed ElKader ElOttol

  5. An acute respiratory disease with three stages: A catarrhal stage with an irritating cough, lasts 1 to 2 weeks. A paroxysmal stage characterized by violent coughs followed by a high respiratory whoop, lasts 2 to 6 weeks. A convalescent stage where the cough gradually decreases in frequency and severity, lasts several weeks. Note: 75% of deaths are among infants.

  6. Signs & Symptoms of Pertussis • The first symptoms of pertussis are similar to those of a common cold: • runny nose • sneezing • mild cough • low-grade fever • Most B.pertussis strains contains peptide that promotes marked lymophocytosis in the host. • The toxin is heat stable. • Elevated white blood cell count with a lymphocytosis, Confirmed with laboratory testing.

  7. Abed ElKader ElOttol

  8. Abed ElKader ElOttol

  9. Organism: • Short, ovoid, gram-negative bacilli. • Aerobic. • Complex, enriched media is required for isolation (Bordet-Gengous). • Non motile, urease negative, nitrate negative. • Laboratory Diagnosis: • Nasopharyngeal swabs or cough droplets, expelled onto "Cough plates" held in front of the mouth of the patient during a paroxysms. • Incubate (Bordet-gengou`s plates) at 35 oC for 2-5 days. • Typical colonies resemble a 1mm droplets of mercury surrounded by a zone of hemolysis. • Colonies are confirmed with specific antiserum Direct immunofluorescent staining of smears made from nasopharyngeal swabs may give a rapid positive test. Abed ElKader ElOttol

  10. Human Disease & Associated Pathogens

  11. Abed ElKader ElOttol

  12. Abed ElKader ElOttol

  13. Legionella pneumophila Abed ElKader ElOttol

  14. Legionellosis was first recognized in association with the epidemic of legionnaires disease which occurred in Philadelphia in July 1976. • Shortly following the epidemic, the causative agent was isolated from lung tissues of patient who died of this disease. • The organism was named Legionella pneumophila. Abed ElKader ElOttol

  15. ORGANISM: Gram negative rods. Stain poorly with gram stain unless safranin is applied for long periods. Slow grower (2-5 days in enriched media containing L-cystein and supplemented source of ferric iron). Old culture may exhibit filamentous forms, swollen rods, and bizarre forms. Soluble pigment that results in brown coloration on Feely-Gorman agar. Good growth obtained on Charcoal-Yeast Extract (CYE). Good growth occur in an atmosphere containing 2.5% CO2. Most strains are flagellated. Abed ElKader ElOttol

  16. Laboratory Diagnosis • Culture gold standard • Require L-cysteine and iron salts • Use BCYE (buffered charcoal yeast extract agar) • Antibiotics might be used to help inhibit the growth of fastidious bacteria • Grown aerobically or • Grow using 3-5% CO2 at 35° for 3 to 5 days • pH 6.9 for optimum growth • Colonies are small with a crystalline-like, ground glass appearance

  17. Abed ElKader ElOttol

  18. Abed ElKader ElOttol

  19. Biochemical Characteristics: • Weak oxidase positive • Strong catalase positive • Liquefy gelatine • No carbohydrate fermentation • No nitrate reduction • No urea hydrolysis • Hydrolysis of hippurate Positive (This differentiate it from other legionella species) • Virulence factors: • 1. Proteolytic enzymes • 2. Exotoxin with lysed laboratory animal RBCs • 3. Cytotoxin which caused inhibition of cell growth in laboratory animals. Abed ElKader ElOttol

  20. Clinical Manifestation: • Acute pneumonia begins 2-10 days after exposure with a brief prodorm of malaise, myalgia, and headache, followed rapidly by prostration, high fever. • an rigors Cough, dyspnea, pleuritic and abdominal pain, vomiting, diarrhea, and unexplained encephalopathy are often seen. • Gram stain of sputum is not diagnostic. • Leukocytosis, elevated ESR, proteinurea, hematuria and abnormal serum enzyme determination are common. • The common causes of death due to respiratory failure and shock. Abed ElKader ElOttol

  21. Abed ElKader ElOttol

  22. Abed ElKader ElOttol

  23. Transmission: • Via respiratory tract. • Collection & Processing of Speciemn: • Caution: Specimen must be handled in a biological safety cabinet. • Lung tissue obtained at autopsy or biopsy is optimally selected from areas ofnecrosis. • A representative portion of specimen should be placed in 10% neutral formalin for Direct Fluorescent Antibody and histopathological examination. • 2. Pleural fluid, transtracheal aspirate. Abed ElKader ElOttol

  24. Abed ElKader ElOttol

  25. Diagnosis: 1. Isolation and identification of Legionella from clinical specimens either on artificial media or guinea pig inoculation followed by embryonated hen`s egg. 2. Demonstration of a four-fold or greater rise in antibody titer from acute phase to convalescent phase by the IFA test. 3. Demonstration of the organism in clinical specimen by DFA. Treatment: Erythromycin is the drug of choice. Abed ElKader ElOttol

  26. BRUCELLA Abed ElKader ElOttol

  27. • Gram-negative bacilli • Chronically infected domestic animals. Medically Important Species B. abortus – Cattles B. melitensis - Goats & sheeps B. canis – Dogs B.suis swine Abed ElKader ElOttol

  28. TRANSMISSION • • Primarily animal disease : Causes abortion & sterility. • Transmission • From animals to animals & humans by: • Abrasion in skin • Inhalation • Ingestion of contaminated milk & cheese • Persons at High Risk • Dairy workers & farmers • Live stock handlers & veternarians • °Slaughterhouse employees Abed ElKader ElOttol

  29. CLINICAL FEATURES OF BRUCELLOSIS (Undulating fever) • Incubation period: 1-3 weeks • Initially influenza-like. Headache, weakness, weight lost, arthralgia, liver dysfunction. • Undulating (rising & falling) fever for weeks & months. • A chronic illness • Splenomegaly • Hepatomegaly • Enlarged lymph nodes Abed ElKader ElOttol

  30. Abed ElKader ElOttol

  31. LAB DIAGNOSIS • Specimens Blood, LN & BM biopsy • Culture Require 5-10% CO2 • Serology ° Antibody titre of 1:160 or more (significant) ° Titre returns to normal within a year of successful treatment TREATMENT • Ciprofloxacin May be up to 6 weeks to prevent relapses Abed ElKader ElOttol

  32. PREVENTION • Pasteurization of milk • Immunization of animals • Eradication of infected livestock • Minimize occupational exposure Abed ElKader ElOttol

  33. End of Lecture Abed ElKader ElOttol

More Related