Lecture 12 Non-sporing anaerobes


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Lecture 12 Non-sporing anaerobes

  1. 1. ‫بسم ا الرحمن الرحيم‬ NON-SPORING ANAEROBES Prof. Khalifa Sifaw Ghenghesh
  2. 2. Part of the Normal Microbial Flora • In the mouth and oropharynx, gastrointestinal tract and female genital tract of healthy individuals. • Gram+ve and Gram – ve cocci, rods and filaments, as well as spiral forms. Wide Variety of Infections • Wound infections • Periodontal disease Most infections are of endogenous origin and polymicrobial (exception > clostridia) Infections in damaged and necrotic tissues, or in the immunocompromised.
  3. 3. Some clinical signs and indicators of non-clostridial anaerobic infections -----------------------------------------------------------------Foul-smelling pus, discharge or lesion Production of a large amount of pus (abscess formation) Proximal of lesion to mucosal surface or portal of entry Failure to isolate organism from pus (sterile pus) Infection associated with necrotic tissue Deep abscess Gas formation in tissues Failure to respond to conventional antimicrobial therapy Pus which shows red fluorescence under UV light Detection of “sulphur granules” in pus (actinomycosis) Infection of human or animal wound bite Gram-negative bacteraemia
  4. 4. Polymicrobial Flora Mixed infections varies according the site affected. 2-12 species or more are involved. May include strict and facultative anaerobes and microaerophilic organisms. Frequently comprise mixtures of Gram —ve rods (e.g. Bacteroides, Prevotella and Fusobacterium species) and Gram+ve cocci (peptostreptococci or streptococci or both)
  5. 5. Non-Sporing Gram-Negative Rods Fusobacterium species • Oral origin (mainly) • Colonize the mucous membranes of humans and animals • Commensals of upper respiratory and gastrointestinal tracts. • Fusobacterium nucleatum Leptotrichia species • Leptotrichia buccalis • “Vincent’s gingivitis”
  6. 6. Bacteroides species and Related Gram —ve rods. 3 Groups: Saccharolytic group >> Most important: • Bacteroides fragilis (group) • Intrabdominal and soft tissue infections below the waist Moderately Saccharolytic group • Prevotella melaninogenica Asaccharolytic group • Porphyromonas asaccharolytica • Porphyromonas gingivalis • Periodontitis
  7. 7. Bacteroides fragilis ssp. fragilis cultured in blood agar medium for 48 hours.
  8. 8. Bacteroides fragilis
  9. 9. Fusobacterium sp.
  10. 10. Gram-Positive Anaerobic Cocci Genus: Peptostreptococcus • P. asaccharolyticus • P. vaginalis Infections in various parts of the body • Abscesses
  11. 11. Types of Infection and Clinical Specimens from which Anaerobic Gram+ve Cocci are Isolated ------------------------------------------------------------------- Blood cultures Central nervous system (including brain abscesses) Head and neck infections (including ear) Dental abscesses and infected root canal Periodontal diseases Human and animal bites Pleural infections Abdominal infections Genito-urinary tract infections Decubitus ulcers Foot ulcers Osteomyelitis -------------------------------------------------------------------
  12. 12. Gram-Negative Anaerobic Cocci Genus: Veillonella • Normal flora of GIT • A regular component of supragingival plaque and the tongue microflora • A minor component of mixed anaerobic infection
  13. 13. Non-Sporing Gram-Positive Rods Present in significant numbers in normal flora of the mouth, skin, GI and female genito-urinary tracts Propionibacterium Bifidobacterium Lactobacillus Actinomyces Eubacterium
  14. 14. Infection of the lachrymal canal (lachrymal canaliculitis) Some species are found in acne Occasionally isolated in infective endocarditis and infection associated with implaned prostheses
  15. 15. Spiral-Shaped, Motile organisms Several Treponema species found in the mouth Mixed anaerobic infections • Acute necrotizing ulcerative gingivitis
  16. 16. Laboratory Diagnosis Adequate clinical specimens are collected (preferably under reducing conditions) and rapidly transported to bacteriology laboratory. Microscopical examination Cultured on proper media and under anaerobic conditions Gas-liquid chromatography • Direct on pus and other clinical materials
  17. 17. Treatment Surgical • Drainage of pus from abscess, debridement, curettage and removal of necrotic tissue Antibiotics • Penicillin, Metronidazole