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Clinical Clinical Treatment Specimen transport and processing PositivePositive Bacilli AnaerobicAnaerobic cocciNegativeNegative Bacilli Environmental Conditions.

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Presentation on theme: "Clinical Clinical Treatment Specimen transport and processing PositivePositive Bacilli AnaerobicAnaerobic cocciNegativeNegative Bacilli Environmental Conditions."— Presentation transcript:

1 Clinical Clinical Treatment Specimen transport and processing PositivePositive Bacilli AnaerobicAnaerobic cocciNegativeNegative Bacilli Environmental Conditions

2 Obligate Anaerobes  only grow in the absence of oxygen (O2) Aerotolerant / Microaerophilic anaerobes  grow in reduced concentration of oxygen (~5% O2), but grow best under strict anaerobic conditions

3 Peptostreptococcus Vieonella??? Get correct spelling

4 Peptostreptococcus (Peptoniphilus) spp. Intestinal gram positive cocci Key reactions Nitrate (+) SPS –sensitive Indole (-) P. assacharolyticus Form tetrads or pairs Key reactions : SPS resistant, Indole (+), Nitrate (-) P. anaerobius Elongated Produce sweet odor due to the presence of isocaproic acid Causes: Head, neck, genital and gut infections

5 Viellonella species Key reactions Nitrate (+) Non-fluorescent, may pigment red Causes : Endocarditis and bacteremia Indigenous to oral cavity, upper respiratory, G.I and genitourinary tract Kanamycin (S ) Vancomycin (R ) Colistin (S) Small Gram negative cocci

6 Clostridium species Others ?????

7 Clostridium spp. Gram positive rods Causes : Food poisoning Gas gangrene(myonecrosis) Neoplasm s Lock jaw Pseudomembraneous colitis Spore formers Found commonly in stool specimen Produce Virulence factors that are responsible for infections Four common species Clostridium perfringens Clostridium difficile Clostridium tetani Clostridium botulism Other Clostridium

8 Appearance: box-shaped gram positive rod Two zone beta hemolytic on SBA Produces alpha and Theta toxin Key reactions: Lecthinase (+), nitrate (+) Reverse camp with group B Strep. Stormy fermentation of litmus milk Kanamycin (S ), Vancomycin (S), Colistin (R) Causes: Gas gangrene, Food poisoning (Enterotoxin A), Soft tissue infections in diabetics and Necrotizing bowel disease

9 Subterminal spore Chartreuse fluorescence Key reactions Ferment fructose Lecthinase (-), Lipase (-) Causes: Pseudomonas colitis and Antibiotic associated diarrhea (AAD) due to enterotoxin A and B

10 Toxin: tetanospasmin (neurotoxic exotoxin) Motile, swarms Appearance: Gram positive rods. Produce terminal spores that appear as drumsticks Biochemical reactions: Lipase (-), Indole (+) Causes: Lockjaw, respiratory failure and tetanus neonatorum

11 Toxin: botulin Key reaction: Lipase (+) Causes: Botulism: Inhibits acetlycholine release from motor neurons

12 Clostridium novyi Beta hemolytic Key reactions : Lecithinase (+), lipase (+), indole (-), urease (-) Causes : Gas gangrene (myonecrosis) and toxic shock Rapid swarmer Characteristic: medusa head, subterminal spores Key reactions: Lipase (-), Indole (-) Causes: Neoplasm of the colon, breast leukemia, lymphoma, enterocolitis. myonecrosis Clostridium septicum

13 Lactobacillus Gram positive Non-spore forming bacilli Normal flora in the oral cavity, G.I. and female genital tract Protect female genital tract Produce lactic acid to lower vaginal pH Infections caused: Bacterial vaginosis Pelvic inflammatory disease Key reactions Catalase (-) Cephalosporin (R) Vancomycin (R )

14 Proprionibacterium acnes Gram positive Non-spore forming bacilli (appear as diptheroids) Normal flora of the skin Can cause: Subacute bacterial endocarditis Bacteremia Reactions Catalase (+) Indole (+) Nitrate (+ )

15 Bacteroides fragilis Bacteroides ureolyticus Fusobacterium nucleatum Fusobacterium necrophorum Other Fusobacterium Porphyromona spp. Prevotella spp.

16 Bacteroides fragilis Key reactions Catalase (+) Indole (-) Nitrate (-) Bile tolerant, Non- motile Causes : Inflammation of the intestinal wall Septic abortion Thrombosis G.I. infections Gram negative rod Penicillin (R ) Kanamycin (R ) Vancomycin (R ) Colistin (R ) Clindamycin (S)

17 Bacteroides ureolyticus Key reaction Urease (+) Bile sensitive, Non- motile Causes : Respiratory infections Intestinal tract infections Gram negative rod Kanamycin (S ) Vancomycin (R ) Colistin (S)

18 Fusobacterium nucleatum Key reactions Lipase (-) Indole (+) Causes : Metastatic brain abscess Fusiform Gram negative bacilli Kanamycin (S ) Vancomycin (R ) Colistin (S)

19 Fusobacterium necrophorum Key reaction Lipase (+) Causes : Pertonsillar abscess in children and young adult Pleomorphic filamentous gram negative rod

20 Prevotella melaninogenica Gram negative coccobacilli Produces foul odor Slow producer of protoporphin Causes : Lung and dental infections Normal flora in the oral, G.I and vaginal area Kanamycin (R ) Vancomycin (R ) Colistin (S) Penicillin (R)

21 Acceptable specimens : Aspirates from sterile site deep wounds, bodily fluids (except urine, sputum and saliva), and suprapubic bladder aspirates Primary media: Brucella (CDC or Schaedler) blood agar- contains hemin, vitamin K and yeast extract. Detect hemolysis in anaerobes Special media: Bacteroides bile esculin (BBE) agar- contains gentamycin (inhibits facultative aerobic gram negative rods ) and 20% bile. Laked Kanamycin Vancomycin (LKV) blood agar – identify pigmented gram negatives. (Kanamycin inhibits facultative gram negative rods and Vancomycin inhibits gram positive rods) Phenyl-ethyl Alcohol (PEA) plate : inhibits swarming Cycloserine cefoxitin fructose (CCFA) agar: selective for Clostridium difficile Egg yolk agar- selective for Lecithinase and lipase production Thioglycollate broth: provides reduced O2 environment

22 Identification tests : Catalase test : distinguish aerotolerant anaerobes from anaerobic organisms Indole : identify organisms that produce tryptophanase (Note: media needs to contain tryptophan) Nitrate test: Urea test: identify organisms that produce urease. Observe pH change. Urea is converted to ammonia Incubate media in anaerobic gas chambers Contains H2, N2, carbon dioxide, palladium catalyst and desiccants (absorb water) Keep media for 7 days

23 Metronidazole – best treatment. Confirms the presence of an anaerobe Clostridium infection: Use antitoxins, antibiotics (i.e. Chloramphenicol, pipercillin, imipramine or ampicillin/sulbactam) and supportive therapy

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