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Non Sporing Anaerobes

Non Sporing Anaerobes. Introduction. Anaerobes bacteria that lack the enzymes superoxide dismutase or catalase or both, makes them susceptible to oxygen derived free radicals Obtain energy from fermentation process Nonsporing anaerobes - Anaerobic bacteria that do not form spores.

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Non Sporing Anaerobes

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  1. Non Sporing Anaerobes Dr Ekta Chourasia, Microbiology

  2. Introduction • Anaerobes • bacteria that lack the enzymes superoxide dismutase or catalase or both, makes them susceptible to oxygen derived free radicals • Obtain energy from fermentation process • Nonsporing anaerobes - Anaerobic bacteria that do not form spores Dr Ekta Chourasia, Microbiology

  3. Habitat of nonsporing anaerobes • Normal flora of skin, mouth, mucous surfaces, respiratory tract, GIT, genital tract • Outnumber aerobes in many habitats • Mouth & skin – 10 to 30 times > aerobes • Intestines – 1000 times > aerobes • Estimated no. of anaerobes in: • Saliva – 108/ ml • Small intestine – 105/ ml • Colon – 1011/ gm Dr Ekta Chourasia, Microbiology

  4. Classification of Non - sporing Anaerobes Dr Ekta Chourasia, Microbiology

  5. Gram negative anaerobic bacilli • Bacteroides • Most common anaerobes isolated from clinical specimens • Pleomorphic, capsulated • Grows on Brain Heart Infusion agar in 10% CO2 • Prevotella & Porphyromonas – pigmented anaerobes • Porphyromonas melanogenica – • black or brown color colonies (due to hemin derivative) • Colonies & even dressings from wounds infected with this bacillus gives a characteristic red fluorescence when exposed to UV light. Dr Ekta Chourasia, Microbiology

  6. Pathogenicities of Gram negative anaerobic bacilli Brain abscess, intra abdominal abscess, infections of female genitalia, cellulitis, diabetic ulcer, septicaemia Bacteroides fragilis Prevotella melaninogenica Lung or liver abscess, empyema, pelvic infections in females, breast abscess, wound infections Porphyromonas Dental root canal infections, periodontal disease Aspiration pneumonia, lung/ liver abscess, oral infections, chronic sinusitis, abdominal infections Fusobacterium necrophorum Fusobacterium nucleatum Dr Ekta Chourasia, Microbiology

  7. Gram positive anaerobic rods • Bifidobacterium – pleomorphic bacilli showing true & false branching • Lactobacillus (Doderlein’sbacilli) – normal flora in mouth, intestine & adult vagina • Mobiluncus – motile, curved, gram variable bacilli Dr Ekta Chourasia, Microbiology

  8. Pathogenicities of Gram positive anaerobic rods Propionibacterium acne Acne Propionibacterium propionicum Cervico - fascial, Pulmonary abscess Bacterial Vaginosis along with Gardenerella vaginalis Mobiluncus Eubacterium Periodontitis Dr Ekta Chourasia, Microbiology

  9. Anaerobic cocci • Peptococcus & Peptostreptococcus – usually produce mixed infections along with clostridia or anaerobic gram negative bacilli • Puerperal sepsis & other genital infections • Wound infections • Gangrenous appendicitis • UTI • Osteomyelitis • Abscesses in brain, lungs & other internal organs Dr Ekta Chourasia, Microbiology

  10. Laboratory Diagnosis • Specimen - Deep aspirates, tissue bits • Collection & transport – • Pre-reduced transport medium • Gassed out vials • Needle & syringe with rubber bunk Dr Ekta Chourasia, Microbiology

  11. Laboratory Diagnosis • Microscopy – Gram stain: many pus cells, variety of different micro-organisms • Culture media • Blood agar • Phenyl ethyl alcohol agar (PEA) • Kanamycin / vancomycin BA • Thioglycollate broth • RCM • Culture methods – Anaerobic jar, Gaspak, Bactec (anaerobic blood culture) Dr Ekta Chourasia, Microbiology

  12. Anaerobic blood culture vials Dr Ekta Chourasia, Microbiology

  13. Laboratory Diagnosis • All cultures must be incubated for 7-10daysas most of the anaerobes are slow growing. • Detection of metabolic products – gasliquid chromatography (GLC) can be directly carried out on pus & other clinical specimens to detect metabolic products like butyric & propionic acid. Dr Ekta Chourasia, Microbiology

  14. Treatment & Prevention • Surgical – • Drainage of pus from abscess • Wound debridement • Curettage & removal of necrotic tissues • Antibiotics – • Metronidazole • Penicillin (cocci) • Clindamycin • Cefamycin Dr Ekta Chourasia, Microbiology

  15. Summary of Anaerobic infections Lab diagnosis Usually endogenous Anaerobic methods of specimen collection & culture Normal flora of the body Poly-microbial Results may take weeks • Precipitating factors • Trauma • Tissue necrosis • Impaired circulation • Diabetes, malnutrition, malignancy • Hematoma or presence of foreign bodies • Prolonged treatment with Aminoglycosides Wound debridement Metronidazole, Clindamycin, Cefamycin Dr Ekta Chourasia, Microbiology

  16. Summary - Non Sporing Anaerobes Abscess: cerebral, epidural subdural CNS Fusobacterium, Peptostreptococcus Propionibacterium Wounds, ulcers, abscess Peptostreptococcus Propionibacterium SSI Pneumonia, empyema, abscess: lung, dental peritonsillar Bacteroides Actinomyces, Fusobacterium, Prevotella, Porphyromonas, Eubacterium Propionibacterium RT GIT Abscess: abdominal, liver, appendicitis Fusobacterium, Eubacterium, Propionibacterium Bacteriodes, Eubacterium Lactobacillus, Mobiluncus, Veillonella FGT Bacterial vaginosis, abscess, septic abortion Dr Ekta Chourasia, Microbiology

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