1 / 18

بسم الله الرحمن الرحيم

بسم الله الرحمن الرحيم. Aerobic Gram-Negative Cocci. Dr. Manal El Said. Head of Microbiology Department. Neisseria. Dr. Manal El Said. Head of Microbiology Department. Neisseria meningitidis (Meningococcus). Diseases.

nhi
Download Presentation

بسم الله الرحمن الرحيم

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. بسم الله الرحمن الرحيم

  2. Aerobic Gram-Negative Cocci Dr. Manal El Said Head of Microbiology Department

  3. Neisseria Dr. Manal El Said Head of Microbiology Department

  4. Neisseria meningitidis (Meningococcus) Diseases - Meningitis(inflammation the meninges of the brain or spinal cord) - Meningococcemia. Characteristics • Gram-negative "kidney-bean" diplococci. • Oxidase-positive. • Large polysaccharide capsule. One of the three classic encapsulated pyogenic bacteria (Streptococcus pneumoniae and Haemophilus influenzae are the other two). Habitat and Transmission • Habitat is the human upper respiratory tract • Transmission is via respiratory droplets.

  5. Neisseria meningitidis (Meningococcus) Pathogenesis • The organism reaches the meninges via the bloodstream. • Endotoxin in cell wall causes symptoms of septic shock. • IgA protease produced. • Capsule is antiphagocytic. • Deficiency in late complement componentsrecurrent meningococcal infections. The characteristic skin rash (purpura) of meningococcal septicemia, caused by Neisseria meningitidis

  6. Neisseria meningitidis (Meningococcus) Laboratory Diagnosis • Gram-stained smear and culture. • Oxidase-positive colonies on chocolate agar. • Ferments maltose in contrast to gonococci, which do not.

  7. Neisseria meningitidis (Meningococcus) Laboratory Diagnosis Round, moist, glistening & convex colonies N. meningitidis - proper streaking and growth on blood agar plate.

  8. Neisseria meningitidis (Meningococcus) - - + + Mal Glu Lac Suc Laboratory Diagnosis

  9. Neisseria meningitidis (Meningococcus) Treatment Penicillin G (no significant resistance). Prevention • Vaccine contains capsular polysaccharide of strains A, C, Y & W-135. • One form of the vaccine contains the polysaccharides coupled to a carrier protein (diphtheria toxoid) and one contains only the polysaccharides. • Rifampin or ciprofloxacin given to close contacts to decrease oropharyngeal carriage.

  10. Neisseria gonorrhoeae (Gonococcus) Diseases • Gonorrhea. • Neonatal conjunctivitis • Pelvic inflammatory disease. Characteristics • Gram-negative "kidney-bean" diplococci. • Oxidase-positive. • Insignificant capsule.

  11. Neisseria gonorrhoeae (Gonococcus) Habitat and Transmission • Habitat is the human genital tract. • Transmission in adults is by sexual contact. • Transmission to neonates is during birth. Pathogenesis • Organism invades mucous membranes inflammation. • Endotoxin weaker than that of meningococcus less severe disease when bacteremiaoccurs. • IgA protease & pili are virulence factors

  12. Neisseria gonorrhoeae (Gonococcus) Laboratory Diagnosis • Gram-stained smear and culture. • Organism visible intracellularly within neutrophils in urethral exudate. • Oxidase-positive colonies. • Gonococci do not ferment maltose (meningococci do). Left: Neisseria gonorrhoeae Gram stain of pure culture; Right: Neisseria gonorrhoeae Gram stain of a pustular exudate.

  13. Neisseria gonorrhoeae (Gonococcus) Laboratory Diagnosis

  14. Neisseria gonorrhoeae (Gonococcus) Treatment • Ceftriaxone for uncomplicated cases. • Tetracycline added for urethritis caused by Chlamydia trachomatis. • High-level resistance to penicillin is caused by plasmid-encoded penicillinase. • Low-level resistance to penicillin is caused by reduced permeability and altered binding proteins.

  15. Neisseria gonorrhoeae (Gonococcus) Prevention • No drug or vaccine. • Trace contacts and treat to interrupt transmission. • Treat eyes of newborns with erythromycin ointment or silver nitrate to prevent conjunctivitis.

  16. Moraxellacatarrhalis • Small coccobacillary gram-negative rod • It causes : • -Otitis media & sinusitis in children. • -Bronchitis & pneumonia in older people with chronic obstructive pulmonary disease • It is found only in humans • It transmitted by respiratory aerosol.

  17. Anaerobic Gram-Negative Cocci Dr. Manal El Said Head of Microbiology Department

  18. Veillonella • Veillonella parvulais an anaerobic gram-negative diplococcus • It is a normal flora of the mouth, colon & vagina. • It is a rare opportunistic pathogen that causes abscesses of the sinuses, tonsils & brain • It is usually in mixed anaerobic infections.

More Related