Prof. Abdullah Akhtar AhmedProf. Abdullah Akhtar Ahmed

Professor of MicrobiologyProfessor of Microbiology

Ibrahim Medical CollegeIbrahim Medical College

Shahbagh, DhakaShahbagh, Dhaka

A. Gram Positive Cocci PeptostreptococcusPeptostreptococcus

P. magnusP. magnus P. P.

asaccharolyticusasaccharolyticus P. prevotiiP. prevotii P. anaerobiusP. anaerobius

PeptococcusPeptococcus P. nigerP. niger

Sarcina ventriculiSarcina ventriculi

Peptostreptococcus Peptostreptococcus N flora of mouth, upper N flora of mouth, upper

respiratory tract, respiratory tract, intestinal tract, vagina & intestinal tract, vagina & skinskin

20-40% of anaerobic 20-40% of anaerobic infectionsinfections Brain abscessBrain abscess Pleuropulmonary Pleuropulmonary

infectionsinfections Female genital tract Female genital tract

infectioninfection

Non Sporing Anaerobe

Non Sporing Anaerobe

VeillonellaVeillonella

C. Gram Positive BacilliC. Gram Positive Bacilli 1. Lactobacillus1. Lactobacillus 2. Bifidobacterium2. Bifidobacterium 3. Actinomyces3. Actinomyces

D. Gram Negative BacilliD. Gram Negative Bacilli 1. Bacteroides1. Bacteroides 2. Fusobacterium2. Fusobacterium 3. 3. PrevotellaPrevotella 4. Porphyromonas4. Porphyromonas

E. SpirochetesE. Spirochetes 1. Treponema1. Treponema 2. Borrelia2. Borrelia

B. Gram negative cocci

Gram positive bacilli. Gram positive bacilli. MicroaerophilicMicroaerophilic Grow in presence of COGrow in presence of CO2 2 and at pH 3.0and at pH 3.0 Widely distributed as saprophytes in fermenting Widely distributed as saprophytes in fermenting

animal and vegetable material (e.g. milk, cheese)animal and vegetable material (e.g. milk, cheese) Normal flora of man and animal in the mouth, gut Normal flora of man and animal in the mouth, gut

and vagina.and vagina. Older textbooks have used the term “Older textbooks have used the term “Doderleins Doderleins

bacillusbacillus” for a variety of human vaginal strains of ” for a variety of human vaginal strains of Lactobacillus.Lactobacillus.

Lactobacillus

Gram Stained Vaginal smear

Role

L. acidophilus L. acidophilus synthesize biotin, Vit. B synthesize biotin, Vit. B1212 and Vit. K in the intestine.and Vit. K in the intestine.

It ferment glycogen which is deposited in It ferment glycogen which is deposited in the vaginal epithelial cells and form lactic the vaginal epithelial cells and form lactic acid. This lactic acid prevent growth of acid. This lactic acid prevent growth of other bacteria by maintains highly acidic other bacteria by maintains highly acidic pH of the vagina. pH of the vagina.

Bacteroides

B. fragilis B. fragilis is most significant.is most significant. Pale irregularly stainingPale irregularly staining Gram negative bacilli/ Gram negative bacilli/

coccobacilli with polysaccharide capsule.coccobacilli with polysaccharide capsule. PleomorphicPleomorphic

Normal flora of large intestine & female genitalNormal flora of large intestine & female genital tract. Normal stool contain 11tract. Normal stool contain 1110 10 B. fragilis B. fragilis organisms per gram. organisms per gram.

Cause abdominal, lung and brain abscesses and Cause abdominal, lung and brain abscesses and wound infectionwound infection

Bacteroides

Bacteroides Virulence Factors

Polysaccharide capsulePolysaccharide capsule LipopolysaccharideLipopolysaccharide AgglutininAgglutinin Histolytic enzymeHistolytic enzyme Oxygen tolerance Oxygen tolerance ββ lactamase lactamase

Fusobacterium Delicate gram negative rodsDelicate gram negative rods

Tapering endsTapering ends F. nucleatumF. nucleatum

Mouth, Upper Resp. tract, GI tract, Mouth, Upper Resp. tract, GI tract, Genital tract Genital tract

Head, neck and lower respiratory Head, neck and lower respiratory tract infectionstract infections

F. necrophorumF. necrophorum Anaerobic tonsillitis/pharyngitisAnaerobic tonsillitis/pharyngitis Involve jugular vein Involve jugular vein Sepsis Sepsis

Lemierre's diseaseLemierre's disease

Lemierre's syndromeLemierre's syndrome (or (or Lemierre's diseaseLemierre's disease) is a disease usually ) is a disease usually caused by the bacterium caused by the bacterium Fusobacterium necrophorumFusobacterium necrophorum, and , and occasionally by other members of the genus occasionally by other members of the genus FusobacteriumFusobacterium ( (F. F. nucleatum, F. mortiferum and F. variumnucleatum, F. mortiferum and F. varium etc.) and usually affects etc.) and usually affects young, healthy adults. Lemierre's syndrome develops most often young, healthy adults. Lemierre's syndrome develops most often after a strep sore throat has created a peritonsillar abscess, a crater after a strep sore throat has created a peritonsillar abscess, a crater filled with pus and bacteria near the tonsils. Deep in the abscess, filled with pus and bacteria near the tonsils. Deep in the abscess, anaerobic bacteria (microbes that do not require oxygen) like anaerobic bacteria (microbes that do not require oxygen) like Fusobacterium necrophorum can flourish. The bacteria penetrate Fusobacterium necrophorum can flourish. The bacteria penetrate from the abscess into the neighboring jugular vein in the neck and from the abscess into the neighboring jugular vein in the neck and there they cause an infected clot (there they cause an infected clot (thrombosisthrombosis) to form, from which ) to form, from which bacteria are seeded throughout the body by the bloodstream bacteria are seeded throughout the body by the bloodstream (bacteremia). Pieces of the infected clot break off and travel to the (bacteremia). Pieces of the infected clot break off and travel to the lungs as emboli blocking branches of the pulmonary artery bringing lungs as emboli blocking branches of the pulmonary artery bringing the heart's blood to the lungs. This causes shortness of breath, chest the heart's blood to the lungs. This causes shortness of breath, chest pain and severe pain and severe pneumoniapneumonia. Fusobacteria are normal inhabitants of . Fusobacteria are normal inhabitants of the oropharyngeal flora. This is a very rare disease with only the oropharyngeal flora. This is a very rare disease with only approximately 160 cases in the last 100 years.approximately 160 cases in the last 100 years.[1][1]

Prevotella & Porphyromonas

Small, pale staining Small, pale staining gram negative gram negative coccobacillicoccobacilli

Dental plaque and Dental plaque and gingival crevices gingival crevices

Infections of oral cavity Infections of oral cavity and upper respiratory and upper respiratory tracttract

Prevotella and Porphyromonas

Some species produce a dark pigmentSome species produce a dark pigment

Pathogenicity

AdherenceAdherence : : agglutinate RBC agglutinate RBC fimbriaefimbriae

CapsuleCapsule : : acidic polysaccharides, acidic polysaccharides, phagocytosis by WBCphagocytosis by WBC

EnzymesEnzymes : : collaginase, protease, collaginase, protease, hyaluronidase, fibrinolysin, hyaluronidase, fibrinolysin, DNAse,…, etc.DNAse,…, etc.

EndotoxinEndotoxin (LPS) : (LPS) : activate C3 activate C3 pathway, PMNs pathway, PMNs

Pathogenicity

• Beta-lactamase productionBeta-lactamase production• B. fragilisB. fragilis – protect themselves and other – protect themselves and other

species in mixed infectionsspecies in mixed infections• Superoxide dismutase productionSuperoxide dismutase production

• Protects bacteria from toxic OProtects bacteria from toxic O22 radicals as radicals as

they move out of usual nichethey move out of usual niche

Anaerobes Commonly Encountered in Infection

Hundreds of anaerobes are part of normal human flora Hundreds of anaerobes are part of normal human flora Only few cause significant infectionsOnly few cause significant infections

Account for 2/3 of clinically significant anaerobic Account for 2/3 of clinically significant anaerobic infections:infections: Bacteroides fragilisBacteroides fragilis group group PrevotellaPrevotella and and PorphyromonasPorphyromonas Fusobacterium nucleatumFusobacterium nucleatum PeptostreptococcusPeptostreptococcus Clostridium perfringensClostridium perfringens

Pathogenic species have “virulence factors” that allow Pathogenic species have “virulence factors” that allow survival outside their niche and to cause diseasesurvival outside their niche and to cause disease

Importance of nonsporing anaerobes

Opportunistic pathogens cause disease in cases of Opportunistic pathogens cause disease in cases of lowered host’s immunity:lowered host’s immunity:

1.1. TraumaTrauma2.2. Tissue necrosisTissue necrosis3.3. Impaired circulationImpaired circulation4.4. AIDSAIDS5.5. Administration of antibiotics, corticosteroids & Administration of antibiotics, corticosteroids &

cytotoxic drugs. cytotoxic drugs. 6.6. DiabetesDiabetes7.7. MalnutritionMalnutrition8.8. MalignancyMalignancy

“MORE IS MISSED BY NOT LOOKING THAN BY NOT KNOWING”Anonymous

Patient examination in the Intensive Care Unit

“MORE IS MISSED BY NOT LOOKING THAN BY NOT KNOWING”Anonymous

Patient examination in the Intensive Care Unit

Thank you

Life is the flower for which love is the honey.Victor Hugo

SAQ – Non sporing anaerobe

1. Classify non sporing anaerobic bacteria.

2. Enumerate the medically important non sporing bacteria.

3. Mention important role of Lactobacilli.

4. Write down the biological property and pathogenesis of B. fragilis.

5. Mention important characteristics and pathogenesis of Fusobacterium.

6. Why non sporing anaerobes are medically important?