NON-SPORE NON-SPORE FORMING ANAEROBIC FORMING ANAEROBIC

BACTERIABACTERIA

S.Y.MaselleS.Y.Maselle

Anaerobic bacteriaAnaerobic 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

Gram positive non-sporulating Gram positive non-sporulating bacilli:bacilli:

● Actinomyces

●Bifidobacterium

●Proprionbacterium ( Corynebacterium)

●Arachnia (Proprionbacterium propionica)

●Eubacterium

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

●Bacteroides ( Bacteroides fragilis).

●Fusobacterium

●Porphyromonas

●Prevotella

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

●Treponema

●Borrelia

●Campylobacter

Anaerobic cocciAnaerobic cocci

Gram positive anaerobic cocci

●Peptostreptococcus

●Peptococcus

Gram negative anaerobic cocci

●Veillonella

●Acidaminococcus

Gram negative non-sporulating Gram negative non-sporulating bacillibacilli

• 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 called Bacteroides

melaninogenicus• But have now been re-classified to two new Genera:• Prevotella which is saccharolytic• Porphyromonas which is asaccharolytic.

FusobacteriumFusobacterium

• 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

Provisional identification of non-spore forming Provisional identification of non-spore forming anaerobic Gram negative bacillianaerobic Gram negative bacilli

Growth in UV-light• 20% bile kanamycin vancomycin colistin pigment fluorecsence catalase

• B.fragilis Yes Resist. Resist. Resist. No No +

• Prevotella No Resist Sens. Sens. Yes Yes -

• Porphyromons No Resist. Sens. Sens. Yes Yes -

• Fusobacterium No Sensit. Resist Sens. No No -

Anaerobes as normal flora 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 urethra both male and female have small numbers of Bacteroides, Prevotera and Fusobacteria spp.

• Uterine cavity : Sterile

Pathogenesis 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

ClinicalClues for anaerobic ClinicalClues for anaerobic infectionsinfections

• -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

Laboratory cluesLaboratory 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.

InfectionsInfections

• 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

Laboratory Diagnosis.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.

TreatmentTreatment

• Surgical drainage and removal of dead and necrotic tissues.

• Combination of antibiotics to cover aerobes and anaerobes.

Anaerobic Gram positive non-Anaerobic Gram positive non-spore forming bacilli.spore forming bacilli.

• Actinomyces cause 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

Anaerobic cocciAnaerobic cocci

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