1. NON-SPORE FORMING ANAEROBIC BACTERIA S.Y.Maselle

2. Anaerobic bacteria

Gram positive sporulating bacilli

Gram positive non-sporulating bacilli

Gram negative non-sporulating bacilli(nm)

Gram negative non-sporulating bacilli(m)

Gram positive anaerobic cocci

Gram negative anaerobic cocci

3. Gram positive non-sporulating bacilli:

Actinomyces

Bifidobacterium

Proprionbacterium ( Corynebacterium)

Arachnia ( Proprionbacterium propionica )

Eubacterium

4. Gram negative non-sporulating bacilli.( non motile)

Bacteroides (Bacteroides fragilis).

Fusobacterium

Porphyromonas

Prevotella

5. Gram negative non-sporulating bacilli (motile)

Treponema

Borrelia

Campylobacter

6. Anaerobic cocci

Gram positive anaerobic cocci

Peptostreptococcus

Peptococcus

Gram negative anaerobic cocci

Veillonella

Acidaminococcus

7. Gram negative non-sporulating bacilli

Prototype-Bacteroides fragilis

Will grow in 20% bile

On blood agar it is non-haemolytic

Gram negative and pleumorphic

Resistant to kanamycin, vancomycin and colistin

Catalase positive

Pigmented strains were formerly calledBacteroides melaninogenicus

But have now been re-classified to two new Genera:

Prevotellawhich is saccharolytic

Porphyromonaswhich is asaccharolytic.

8. Fusobacterium

Long thin gram negative rods with pointed ends

May or may not grow in 20% bile

Catalase negative

Sensitive to kanamycin and colistin but resistant to vancomycin

9. Provisional identification of non-spore forming anaerobic Gram negative bacilli

Growth inUV-light

20% bilekanamycinvancomycincolistinpigmentfluorecsence catalase

B.fragilisYesResist.Resist.Resist.NoNo+

PrevotellaNoResistSens.Sens.YesYes-

Porphyromons NoResist.Sens.Sens.YesYes-

FusobacteriumNoSensit.ResistSens.NoNo-

10. Anaerobes as normal flora

Anaerobic bacteria are the predominant normal human bacterial flora.

Bacteroides and Prevotera spp are the most predominant.

In the mouth : Prevotella, Fusobacterium, Porphylomonas and anaerobic cocci.

In stomach:mostly facultative anaerobes in low counts.

Terminal ileum:Bacteroides, Bifidobacterium and facultative anaerobes.

Colon:Highest concentration of bacteria, mostly Bacteroides, Fusobacteria,Clostridia, anaerobic cocci, Bifidobacteria and facultative anaerobes.

Vagina : mostly anaerobes especially gram positive rods, but may vary depending on menstral cycle, pregnancy, menopause and other gynaecological conditions.

Distal urethraboth male and female have small numbers of Bacteroides, Prevotera and Fusobacteria spp.

Uterine cavity: Sterile

11. Pathogenesis

Synergy with aerobic bacteria is essential in the pathogenesis

But also there are several virulence factors involved in the pathogenesis

Capsular polysaccharide inhibits phagocytosis, enhences abscess formation.

Pili and fimbriae enhence adherence

Lipopolysaccharide endotoxin enhences abscess formation.

Succinic acid-inhibits phagocytosis

Enzymes like hyaluronidase, collagenase, neuraminidase, heparinase, fibrinolysins etc

12. ClinicalClues for anaerobic infections

-Foul smelling pus

-Proximity to mucosal surfaces.

-Massive necrotic tissues

-Septic thrombophlebitis

- Infection following human bite

Septic abortion

Infection following lower GIT and female genital surgery

13. Laboratory clues

Purulent exudate but no bacterial growth on culture

Foul smelling culture plates

Colonies fluoresce brick red under UV light

Failure to grow organisms seen on gram stain.

14. Infections

Oral cavity eg dental abscess, periodontal disease, acute gingivitis.

Intra abdominal eg. peritonitis, abcsesses etc

Sinuses(chronic sinusitis)

Female genital tract eg pelvic inflamatory disease(PID), endometritis,pelvic abcsess, bacterial vaginosis etc.

Pleuro-pulmonary infections eg aspiration pneumonia, lung abcsess, empyema etc

Bacteraemia and septicaemia and metastatic abcsesses

15. Laboratory Diagnosis.

Isolation: good specimen, use selective and non-selective media, good anaerobic incubation and identify by biochemical tests and gas-liquid-chromatography and molecular techniques if available.

16. Treatment

Surgical drainage and removal of dead and necrotic tissues.

Combination of antibiotics to cover aerobes and anaerobes.

17. Anaerobic Gram positive non-spore forming bacilli.

Actinomycescause actinomycosis

Bifidobacterium branched, normal flora in GIT.

Eubacterium- mouth and bowel normal flora.

Rothia- normal flora in mouth. Also in periodontal disease.

Lactobacillus-normal flora in vagina

Propionibacterium- on skin as normal flora

18. Anaerobic cocci

Peptococci and Peptostreptococci present in mouth,gut, female genital tract together with other anaerobes may be responsible for all above mentioned infections.