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Nonsporing anaerobes
- 1. Dr Vishal Kulkarni MBBS MD (Microbiology) Nonsporing Anaerobes
- 2. Introduction Anaerobes Are bacteria which are able to live in relative or total absence of Oxygen. Nonsporing anaerobes Classified on the basis of DNA base composition and analysis of fatty acid product metabolism.
- 3. Classification Cocci Gram positive Peptostreptococcus spp. Peptococcus spp Gram negative Veillonella Bacilli Gram positive Eubacterium Propinibacterium Lactobacillus Mobilincus Bifidobacterium Actinomyces
- 4. Gram negative bacilli Bacteroides Prevotella Porphyromonas Fusobacterium Leptotrichia Spirochetes Treponema Borrelia
- 5. Cultural characteristics- Grow in absence of molecular oxygen Optimum temp- 37˚C Optimum pH- 7.0-7.4 Incubation period- 48 hrs or more Grow well on freshly prepared/pre-reduced BA P.melaninogenicus
- 6. Predisposing factors- Deep seated wounds Tissue necrosis Impaired circulation Diabetes Malnutrition Trauma, foreign bodies Malignancy Prolonged T/t with aminoglycosides
- 7. Pathogenesis- Lowering of Eh Concomitant bacterial infection Virulance factors Toxins Enzymes Capsule Extracellular products.
- 9. Diseases produced by nonsporing anaerobes- Female genital tract infections- Vaginitis Bartholin’s abscess Puerperal sepsis PIDs Post-operative wound infections Most commonly caused by P. melaninogenica, B fragilis, Peptococci, Peptostreptococci, Fusobacteria
- 10. Abdominal infections Appendicitis, diverticulitis, peritonitis, biliary tract infections, SSIs Bacteroides spp, and anaerobic cocci ENT infections Otitis media, mastoiditis, sinusitis, tonsillitis Fusobacteria Orodental infections Gingivitis, dental abscess, mandibular space infection, periodontal infections
- 11. Fusobacteria, spirochaetes, actinomycetes Respiratory infections Aspiration pneumonia, lung abscess, empyma Fusobacteria, P. melaninogenicus, B. fragilis, A. cocci Other infections Bacteremia, bone infections, brain abscess, cellulitis, necrotising fascitis Bacteroides spp, prevotella spp
- 12. Clues to guide presumptive diagnosis ? • Foul smelling odour • Gas in specimen • Pronounced cellulitis • Chronic ulcers/ deep abscesses refractory to standard T/t • Black pus • Negative aerobic culture (Microscopy positive)
- 13. Lab Diagnosis Specimen Collection Avoid contamination Closed abscess- aspiration by syringe & needle Female genital tract- culdocentesis Respiratory tract- aspiration/ lung puncture Pleural cavity- thoracocentesis Tissue- excision Urinary tract- needle aspiration of bladder
- 14. Transport- Protect specimen from lethal effect of O2 Swab- Stuart media/ RCM Aspiration- material is injected through rubber stopper in bulb containing CO2 Syringe- needle is inserted in a sterile rubber stopper after expulsion of air bubble Blood- BHI broth/ thioglycolate broth
- 15. Processing of specimen Gross examination Black color Foul smelling Direct microscopy Gram stain Polymicrobial picture Lactobacillus spp.Bacteroids spp.Fusobacterium spp.
- 16. Culture Plain freshly prepared blood agar Neomycin blood agar Neomycin- Kanamycin blood agar Phenyl ethyl alcohol blood agar Kanamycin vancomycin blood agar (for GNBs) After inoculation, plates are incubated anaerobically in McIntosh- Filde’s jar Gas pack jar Anaerobic glove box
- 17. McIntosh Filde’s Jar Gaspak Jar Anaerobic glove box
- 18. Ultraviolet examination- Bright red fluorescence in case of P. melaninogenica. Rapid Identification with Gentamicin and metronidazole disc Rapid identification by biochemical tests API (Indole, urea, gelatin, esculin, catalase) Minitek BBL Gas liquid chromatography
- 19. Detection of antigen Co-agglutination Direct immunofluorescence Agglutination Haemagglutination PAGE ELISA
- 20. Antibiotic susceptibility testing Routine is unnecessary Serious infections (endocarditis, brain abscess etc) Methods Broth dilution Agar dilution Broth disc test Disc diffusion
- 21. Antibiotics commonly prescribed Penicillin Tetracycline Chloramphenicol Clindamycin Metronidazole (DOC) Co-trimoxazole Amoxyclav Ampicillin/ sulbactam In some infections surgical interventions are needed.
- 22. Thank You…