UII ANAEROBnmugku
-
Upload
dito-trunogati -
Category
Documents
-
view
233 -
download
4
Transcript of UII ANAEROBnmugku
-
7/27/2019 UII ANAEROBnmugku
1/30
ANAEROBES
BACTERIA
Titik Nuryastuti
Microbiology DepartmentFac of Medicine UGM
-
7/27/2019 UII ANAEROBnmugku
2/30
Classification of Medically
Important Anaerobes
Grampositivecocci
Peptostreptococcus
Gramnegativecocci
Veillonella
Grampositivebacilli Clostridiumperfringens,tetani,botulinum,difficile
Propionibacterium
Actinomyces
Lactobacillus
Eubacterium,bifidobacterium,arachnia
Gramnegativebacilli Bacteroidesfragilis
Fusobacterium
Prevotella
Porphyromonas
-
7/27/2019 UII ANAEROBnmugku
3/30
Definitions
Anaerobes
Bacteria that require anaerobic conditions to initiate and sustain
growth
No Ability to live in oxygen environment
Ability to utilize oxygen for energy instead of fermentation or
anaerobic respiration (except obligate anaerobe) Strict (obligate) anaerobe
Unable to grow if > than 0.5% oxygen
Moderate anaerobes
Capable of growing between 2-8% oxygen
Microaerophillic bacteria Grows in presence of oxygen, but better in anaerobic conditions
Facultative bacteria (facultative anaerobes)
Grows both in presence and absence of oxygen
-
7/27/2019 UII ANAEROBnmugku
4/30
Metabolism
-
7/27/2019 UII ANAEROBnmugku
5/30
Growth anaerobic bacteria in GAM
-
7/27/2019 UII ANAEROBnmugku
6/30
Epidemiology
Endogenous infections
Indigenous microflora
Skin: Propionibacterium, Peptostreptococcus
Upper respiratory: Propionibacterium
Mouth: Fusobacterium, Actinomyces Intestines: Clostridium, Bacteroides, Fusobacterium
Vagina: Lactobacillus
Flora can be profoundly modified to favor anaerobes
Medications: antibiotics, antacids, bowel anti-motility agents
Cancers Exogenous infections
Spore forming organisms in soil, water, sewage
-
7/27/2019 UII ANAEROBnmugku
7/30
Role of Anaerobes
Prevent colonization & infection by
pathogens
Bacterial interference through elaboration of
toxic metabolites, low pH, depletion ofnutrients
Interference with adhesion
Contributes to host physiology Bacteroides fragilis synthesizes vitamin K and
deconjugates bile acids
-
7/27/2019 UII ANAEROBnmugku
8/30
Clinical features of anaerobic
infections
The source of infecting micro-organism is
the endogenous flora of host
Alterations of hosts tissues provide suitableconditions for development of opportunist anaerobic
infections
Anaerobic infections are generally
polymicrobial Abscess formation
Exotoxin formation
-
7/27/2019 UII ANAEROBnmugku
9/30
Virulence factors
Attachment and adhesion
Polysaccharide capsules and pili
Invasion
Aerotolerance Establishment of infection
Polysaccharide capsule (B. fragilis) resists
opsonization and phagocytosis
Synergize with aerobes Spore formation (Clostridium)
Tissue damage
Elaboration of enzymes, toxins
-
7/27/2019 UII ANAEROBnmugku
10/30
Sites of anaerobic infections
-
7/27/2019 UII ANAEROBnmugku
11/30
Risk factor
-
7/27/2019 UII ANAEROBnmugku
12/30
Anaerobic cocci
Epidemiology
Normal flora of skin, mouth, intestinal and genitourinary tracts
Pathogenesis
Virulence factors not as well characterized
Opportunistic pathogens, often involved in polymicrobial
infections Brain abscesses, periodontal disease, pneumonias, skin and soft
tissue infections, intra-abdominal infections
Peptostreptococcus
P. magnus: chronic bone and joint infections, especially
prosthetic joints
P.prevottiand P. anaerobius: female genital tract and intraabdominalinfections
Veillonella
Normal oral flora; isolated from infected human bites
-
7/27/2019 UII ANAEROBnmugku
13/30
Anaerobic gram positive bacilli
No Spore Formation
Propionibacterium
P. acnes
Actinomyces
A. israelii
Lactobacillus Eubacterium, bifidobacterium, arachnia
Spore Formation
Clostridium
C.perfringens C. difficile
C tetani
C. botulinum
-
7/27/2019 UII ANAEROBnmugku
14/30
Propionibacterium
Produces propionic acid as major by product of
fermentation
Colonize skin, conjunctiva, external ear,
oropharynx, female GU tract P. acnes
Acne
Resides in sebaceous follicles, releases LMWpeptide, stimulates an inflammatory response
Opportunistic infections
Prosthetic devices (heart valves, ventricularshunts)
-
7/27/2019 UII ANAEROBnmugku
15/30
Actinomyces
Facultative or strict anaerobe
Colonize upper respiratory tract, GI, female GU
tract
Actinomycosis
Endogenous disease, no person-person spread Low virulence; development of disease whennormal mucosal barriers are disrupted (dentalprocedure)
Diagnosis made by examination of infected fluid:
Macroscopic colonies of organisms resemblinggrains of sand (sulfur granules)
Culture
-
7/27/2019 UII ANAEROBnmugku
16/30
ACTINOMYCES
Anaerobic, filamentous, gram positive bacillus
Exhibit true branching
Mykes Greek forfungus
Thought by early microbiologist to be fungi
because of:
Morphology
Disease they cause
-
7/27/2019 UII ANAEROBnmugku
17/30
Actinomycosis
Cervicofacial Actinomycosis
Poor oral hygiene, oral trauma,
invasive dental
procedure Chronic granulomatous
lesions that become
suppurative and form sinus tracts
Slowly evolving, painless process Treatment: surgical debridement and
prolonged penicillin
-
7/27/2019 UII ANAEROBnmugku
18/30
Lactobacillus
Facultative or strict anaerobes
Colonize GI and GU tract
Vagina heavily colonized by Lactobacillus
crispatus &jensonii
Certain strains produces H2O2 which isbactericidal to Gardnerella vaginalis
Clinical disease (rarely)
Transient bacteremia from GU source
Bacteremia in immunocompromized host
Endocarditis
-
7/27/2019 UII ANAEROBnmugku
19/30
Anaerobic gram negative bacilli
Bacteroides
B. fragilis
B. thetaiotaomicron
Fusobacterium
Prevotella
Porphyromonas
-
7/27/2019 UII ANAEROBnmugku
20/30
Anaerobic gram negative bacilli
Clinical Diseases
Chronic sinus infections
Periodontal infections
Brain abscess
Intra-abdominal infection
Gynecological infection
Diabetic and decubitus ulcers
-
7/27/2019 UII ANAEROBnmugku
21/30
Bacteroides
Epidemiology
B. fragilis associated with 80% of intra-abd infx
Peritonitis, intraabdominal abcesses
Diabetic foot ulcers
Pathogenesis
Polysaccharide capsule
Increases adhesion to peritoneal surfaces (along with fimbriae)
Protection against phagocytosis
Differs from LPS of aerobic GNR
Less pyrogenic activity
Abscess Formation
Produces superoxide dismutase and catalase Elaborate a variety of enzymes
Synergistic infections with aerobes
-
7/27/2019 UII ANAEROBnmugku
22/30
How to diagnose anaerob infection
Foul-smelling discharge (due to short chain FAproduct of anerobic metabolism)
Infection in proximity to a mucosal surface
Gas in tissue (CO2 and H2)
Negative aerobic cultures
Medium can be used : TSA agar, BHI agar, Brucellaagar supplemented with hemin, blood, added withkanamycin (or other aminoglycosides)
-Incubates at 37C, in anaerobic conditions-Observe morphology, pigmentation, microscopicex., biochemical test
-
7/27/2019 UII ANAEROBnmugku
23/30
Treatment
Mixed infection :
surgical drainage
Most active AB : clindamycin, metronidazole
Others : cephalosporine, piperacillin, penicillinG
-
7/27/2019 UII ANAEROBnmugku
24/30
Conclusion
Anaerobic infections
Endogenous or exogenous
Alteration of host tissue
Break in anatomic barrier
Devitalized tissue
Polymicrobial
Synergy between anaerobes and facultative
bacteria
Abscess formation
Exotoxin elaboration
-
7/27/2019 UII ANAEROBnmugku
25/30
Abscess Formation
Initial phase
Introduction of bacteria and inflammatory exudates (esp. fibrin)
Microbial persistence (localization)
Impaired bacterial clearance: fibrin deposition, platelet
clumping Impaired phagocytic function: fibrin, hemoglobin
Impaired neutrophil migration and killing: hypoxia, low PH
Complement depletion: necrotic debris
Development of mature abscess
Central core of necrotic debris, dead cells, bacteria Surrounded by neutrophils and macrophages
Peripheral ring of fibroblasts and smooth muscle cells within
collagen capsule
-
7/27/2019 UII ANAEROBnmugku
26/30
clostridium
-
7/27/2019 UII ANAEROBnmugku
27/30
Gram negative, pleomorphic bacilli
Resistance to PenG, Cephalosporin,
tetracycline
produce beta-lactamase
bile-tolerant
-
7/27/2019 UII ANAEROBnmugku
28/30
ACTINOMYCOSIS
Not highly virulent (Opportunist) Component of Oral Flora
Periodontal pockets Dental plaque Tonsilar crypts
Take advantage of injury to penetrate mucosalbarriers Coincident infection Trauma Surgery
-
7/27/2019 UII ANAEROBnmugku
29/30
Pulmonary Actinomycosis
15% of cases
Aspiration of organism from the oropaharynx
Slowly progressive process involving lung
and pleura May be mistaken for malignancy
Chest pain, fever, wgt loss and hemoptysis
-
7/27/2019 UII ANAEROBnmugku
30/30
Form indurated masses with fibrous walls and centralloculations with pus Pus contains "Sulfur Granules"
Gritty, yellow white Average diameter - 2mm Composed of mineralized mycelial mass
Chronic infection
Form burrowing sinus tracts to skin or mucusmembranes Discharge purulent material