Haemophilus

1. Haemophilus

2. HISTORY • Hib was found in a group of patients during an influenza outbreak in 1892 • Haemophilus influenzae was first isolated in 1890 by Richard Pfeiffer

3. HISTORY Robert Koch – 1883 – conjunctivitis Pfeiffer – 1889–92 – influenza pandemic Smith, Andrews and Laidlaw – virus

4. Medically important spp • H.aegyptius (Koch. • Weeks) • H.Para Influenzae • H.Para haemolyticus • H.araphrophitus • H. Influenzae • H.ducreyi • H. haemolyticus. • H. aphrophilus • H.segnis

5. HAEMOPHILUS H. influenza – meningitis, epiglotitis, pneumonia H. aegypticus – epidemic conjunctivitis H. ducreyi – chancroid H. parainfluenza } H. aphrophilus} infective Endocarditis

6. Morphology • Haemophilus influenzae is : • a pleomorphic gram-negative coccobacillus. • H.influenzae may be either encapsulated (typeable) or unencapsulated (nontypeable). • There are six encapsulated serotypes (designated a–f) that have distinct capsular polysaccharides.

7. MORPHOLOGY Sputum – coccobacillary forms CSF – long bacillary filaments Young cultures – coccobacillary Older cultures – pleomorphic Acute infection – capsulated

8. CULTURAL CHARACTERS • Extracellular pathogen, does not invade into cells • Fastidious • Haemophilus = blood loving • However, this organism can not grow on blood agar alone! • Requires X factor • Requires V factor

9. CULTURAL CHARACTERS Aerobic, 10% CO2 X factor – heat stable hemin/porphyrins V factor – heat labile – RBC – Staphylococci/fungi Co-enzyme – NAD or NADP

10. X and V factor: • X factor is used by H. influenzae to produce essential respiratory enzyme such as cytochrome – catalase and peroxidase. • V Factor is used as electron carriers in the organism oxidation reduction system

12. Species Growth Factor Required --------------------------------- H. influenzae X + V H. parainfluenzae V H. aphrophilusX H. ducreyi X

13. SATELLITISM • H influenzae inoculated on blood agar plate • S aureus streaked across on same plate • Incubate at 37C for 18-24 hrs • Colonies of H influenzae near the S aureus streak are large and well developed than those farther away from S aureus streak • V factor is available in high concentrations near S aureus streak

14. SATELLITISM H.influenzae on blood agar showing satellitism around S.aureus streaks

15. BIOCHEMICAL REACTIONS Catalase-positive, oxidase-positive Eight biotypes Biotype I – meningitis

16. ANTIGENIC PROPERTIES Three main surface antigens Capsular polysaccharide – 6 capsular types a–f Type b – polyribosyl ribitol phosphate (PRP) antigen Non-typeable – lacking capsule Outer membrane protein antigen or OMP Ags Hib – 13 subtypes Lipooligosaccharides (LOS) – antigenically complex

17. PATHOGENICITY Capsular polysaccharide PRP -antiphagocytic Membrane Lipopolysacchride – bacterial attachment, invasiveness, paralysis-ciliated respiratory epithelium IgA protease – inactivates secretory antibodies

18. PATHOGENESIS • Spread via respiratory droplets • Enters upper respiratory tract and throat and attaches to cells using fimbriae • Endotoxin stops respiratory tract cilia from beating and clearing the bacterial cells • Local spread (ears, sinuses, lungs) • Systemic spread (blood and brain) • Endotoxin and inflammation do the damage

19. PATHOGENESIS Clinical syndrome – invasive, non-invasive Invasive – meningitis, laryngoepiglottitis, pneumonia, suppurative lesions, bronchitis Non-invasive – otitis media, sinusitis

20. CLINICAL SYNDROMES • Pyogenic (purulent) meningitis in young children (2 month to 3 years) olds • Acute epiglotitis (Croup) (2 – 7 years old) • Cellulitis – pyogenic arthritis, osteitis conjunctivitis, middle ear infections, and pneumonia.

21. CLINICAL SYNDROMES • Non Capsulated H. Influenzae strains are associated with less severe but often persistent infections such as • purulent exacerbations of chronic bronchitis (Mainly in adult), • Conjunctivitis, middle ear infection • paranasal sinusitis

22. LABORATORY DIAGNOSIS CSF, pus, sputum, blood culture NEVER REFRIGERATE SPECIMEN Microscopy – Gram-negative bacteria Culture isolation – chocolate agar, blood agar, Levinthal’s medium, Field’s agar SATELLITISM Serology – CSF, body fluids – type ‘b’ polysaccharide – CIEP, Latex Agglutination, coagglutination, PCR

23. PROPHYLAXIS Immunoprophylaxis – purified PRP Conjugate vaccines Purified PRP – Hib PRP Conjugate – TT, DPT

24. HAEMOPHILUS AEGYPTICUS Koch Week’s bacillus Brazil – 1984 – conjunctivitis – septicemia, Brazilian purpuric fever Koch – 1883 – Egypt, Week – cultivated1887 – New York It requires X and V factor. H. aegypticus – pink eye Brazilian purpuric fever

25. CLINICAL SYMPTOMS Pink eye Endemic – South America Rx – Chloramphenicol + Ampicillin

26. HAEMOPHILUS DUCREYI • Short ovoid bacilli • End to end pairing in • short chains • Morphology – bipolar • staining, school of fish • ‘railroad track’ • Chancroid – soft sore • Ducrey – 1890 – chancroid lesion

27. Chancroid • STD transmission • Chancroid – soft sore • papule, non Indurated painful ulcer, enlarged lymph nodes (bubos) • Lab diagnosis • Smear: Gram negative bacilli (school of fish) bipolar staining. • Isolation – rabbit fresh clotted blood, CAM, CA- isovitalex and fetal calf serum – 2–8 days – 35°C, 10% CO2 only X factor

28. OTHER HAEMOPHILUS H. parainfluenza; only V Commensal – URT SABE – urethritis – acute pharyngitis H. haemolyticus – X and V – non-pathogenic H. aphrophilus – X, high CO2 – endocarditis, brain abscess, sinusitis H. paraphrophilus – V

29. HACEK Fastidious – commensal – mouth H – H. parainfluenza, aphrophilus, paraphrophilus A – Actinobacillus C – Cardiobacterium hominis E – Eikenellacorrodens K – Kingellakingae Endocarditis – blood cultures – 7–30 days Drug resistance common