Patcharasarn Linasmita MD HRH Princess Maha Chakri Sirindhorn Medical Center
Srinakharinwirot University
1. Obligate aerobes 2. Obligate anaerobes 3. Facultative anaerobes 4. Microaerophiles 5. Aerotolerant anaerobes
http://en.wikipedia.org/wiki/File:Anaerobic.png
1. Obligate aerobes need oxygen cannot ferment or respire anaerobically gather at the top of the tube where the oxygen
concentration is highest
http://en.wikipedia.org/wiki/File:Anaerobic.png
2. Obligate anaerobes are poisoned by oxygen gather at the bottom of the tube where the
oxygen concentration is lowest.
http://en.wikipedia.org/wiki/File:Anaerobic.png
3. Facultative anaerobes (or facultative aerobes/organisms)
can grow with or without oxygen can metabolize energy aerobically or anaerobically gather mostly at the top because aerobic respiration
generates more ATP than either fermentation or anaerobic respiration
http://en.wikipedia.org/wiki/File:Anaerobic.png
4. Microaerophiles need oxygen because they cannot ferment or
respire anaerobically Need only 2 – 10% oxygen
are poisoned by high concentrations of oxygen
http://en.wikipedia.org/wiki/File:Anaerobic.png
5. Aerotolerant anaerobes do not require oxygen they metabolize energy anaerobically are not poisoned by oxygen They can be found evenly spread throughout the test
tube
http://en.wikipedia.org/wiki/File:Anaerobic.png
1. Obligate aerobes 2. Obligate anaerobes 3. Facultative anaerobes 4. Microaerophiles 5. Aerotolerant anaerobes
http://en.wikipedia.org/wiki/File:Anaerobic.png
Survive in low concentration oxygen? Anaerobic or anaerobic respiration For No2. Only moderately obligate anaerobes with
relative aerotolerance can survive ▪ “Strict obligate anaerobes” will be rapidly killed by oxygen
?? ??
Poisoned by atmospheric oxygen? Atmospheric oxygen = 21% For No2. “Strict obligate anaerobes” will be
rapidly killed by very low concentration of oxygen
Mucous membrane Oral / nasal / pharynx / upper respiratory Gastrointestinal tract Female genital tract
Skin
Cohen-Poradosu R, Kasper DL. Chapter 243. Anaerobic Infections: General Concepts.
In: Mandell GL, Bennett JE, Dolin R. eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 7e.
Philadelphia: Churchill Livingstone; 2010.
Oral Prevotella, Porphyromonas spp. (most common) Fusobacterium Bacteroides (non-Bacteroides fragilis group)
Colon Bacteroides (especially Bacteroides fragilis group -
B. fragilis, B. thetaiotaomicron, B. ovatus, B. vulgatus, B. uniformis, Parabacteroides distasonis ) (most common)
Clostridium, Peptostreptococcus, Fusobacterium spp.
Female genital tract Prevotella bivia, Prevotela disiens (most common)
Fusobacterium, Clostridium, Lactobacillus spp. Bacteroides spp. 50% of women Bacteroides fragilis ~ 15% 0f Bacteroides spp.
Skin Propionibacterium acnes (most common)
Peptostreptococcus spp.
Mediators of physiologic, metabolic, immunologic functions in mammalian hosts Production of vitamin K Regulation in carbohydrate and fat absorption Influences the development of an intact mucosa
and mucosal-associated lymphoid tissue
Colonization resistance Depletion of nutrients Depletion of oxygen (by facultative organisms) Production of bactericidal lectin
Gram positive bacilli (spore forming) Clostridium spp.
Gram positive bacilli (non-spore forming) Actinomyces spp. Propionibacterium spp.
Gram negative bacilli Bacteroides, Prevotella, Porphyromonas,
Fusobacterium spp. Gram positive cocci Peptostreptococcus spp.
Clostridium perfringens Habitat: Soil, intestine Tissue necrosis, myonecrosis, gas gangrene
Clostridium septicum Typhlitis (neutropenic enterocolitis) Bacteremia, soft tissue infection : associated
with malignancy Clostridium sordellii Septic abortion
Clostridium botulinum Botulism
Clostridium tetani Tetanus
Clostridium difficile Pseudomembranous colitis Antibiotic associated colitis
Clostridium septicum: note the spores (arrows) within the rods. Murray, Patrick R., PhD - Medical Microbiology, 327-338.e1
© 2013 Copyright © 2013 by Saunders, an imprint of Elsevier Inc.
Actinomyces spp. Filamentous, branching Sulfur granule Oral mucosa / female genital tract / GI tract Abscess: oral cavity, face, neck, brain, Chronic aspiration Abdominal / pelvic actinomycosis – associated
with intrauterine device usage May mimics malignant tumor
Propionibacterium spp. Habitat: Skin Acne vulgaris Infections of foreign body / medical devices ▪ Ventriculoperitoneal shunt ▪ Pacemaker ▪ Prosthetic heart valve ▪ Prosthetic joint
Bacteremia (rare)
Bacteroides spp. Bacteroides fragilis group – (most common) ▪ Habitat : ▪ GI tract (common) ▪ female genital tract (less comon)
▪ Production of beta-lactamase
Porphyromonas spp. Habitat: oropharynx, nasopharyx
Prevotella spp. Pigmented Prevotella ▪ P. melaninogenica, P. intermedia ▪ Oropharyx
Nonpigmented Prevotella ▪ P. oralis, P. oris ▪ Oropharyx
▪ P. bivia, P. disiens ▪ Female genital tract
Fusobacterium spp. Habitat: oropharynx, female genital tract Periodontitis, gingivitis, oral infection Fusobacterium nucleatum ▪ Most common
Fusobacterium necrophorum ▪ Lemierre's syndrome ▪ (thrombophlebitis of internal jugular vein)
Peptostreptococcus spp. (most common)
Skin, oropharyx, intestine, female genital tract Peptococcus spp. Skin, oropharyx, intestine, female genital tract
Presence of anaerobes Inoculation Translocation ▪ Disruption of mucosa ▪ Contiguous spreading ▪ Bacteremia
Anaerobic conditions Inadequate vascular supply ▪ Infarction / necrosis
obstruction
Diabetes mellitus Postsplenectomy Steroid Cytotoxic drug Neutropenia Solid organ tumor Hematologic malignancy Post surgical Chronic infections Vascular insufficiency
Exotoxin Clostridial toxin ▪ Alpha toxin, theta toxin – C. perfringens ▪ Clostridial difficile toxin
Bacteroides fragilis ▪ Enterotoxin -> diarrhea
Fusobacterium ▪ leukotoxin
Lipopolysaccharide Endotoxin Especially in Fusobacterium spp.
Capsule Capsular Polysaccharide Especially in Abscess formation by Bacteroides fragilis
Lytic enzymes Collagenase, phosphatase, lipase, protease, elastase,
hyaluronidase
Anaerobic bacteria Recovered in infections at all anatomic locations Types & frequencies depend on the microbial flora ▪ Sources of infections ▪ Adjacent mucocutaneous sites ▪ Contiguous spreading
Usually in chronic infections Synergy with aerobes / facultative anaerobes
Sources: chronic infections ears, mastoids – to temporal lobe, cerebellum Sinuses – to frontal lobe oropharynx, teeth, lungs – hematogenous
Endocarditis – hematogenous (rare cause)
Complications of dental and respiratory infections Prevotella, Porphyromonas, Bacteroides,
Fusobacterium, Peptostreptococcus spp.
Microaerophilic streptococci Actinomyces - (less frequent)
VP Shunt Infections Propionibacterium acnes - skin Bacteroides fragilis – intestine / peritonitis
Trauma / injury / surgery Clostridium perfringens
Antibiotic Good blood-brain barrier penetration Metronidazle (combined with ceftriaxone) Meropenem (monotherapy) Chloramphenicol (rarely used due to side effect) Poorer penetration Betalactam/betalactamase inhibitors
Surgical drainage – may be needed
Anaerobes involvement in chronic infections Oropharyngeal flora Prevotella, Porphyromonas, Bacteroides,
Fusobacterium, Peptostreptococcus spp. Dental infections Pulpitis, gingivitis, periodentitis Periapical abscess, root abscess
Deep neck infections
Acute necrotizing ulcerative gingivitis (ANUC) Trench mouth
Causative organisms Prevotella intermedia Fusobacterium spp. Anaerobic spirochete
Otitis media Mastoiditis Sinusitis Parotitis Cervical lymphadenitis Tonsillitis / peritonsillar abscess Postsurgical infections
Orbital cellulitis Osteomyelitis Meningitis Carvernous sinus thrombosis Epidural abscess Subdural abscess Brain abscess
Complication of tonsillitis / peritonsillar abscess Thrombophlebitis of the internal jugular vein Septic embolism – lung (most common), liver,
spleen, joint, pericardium, endocardium Fusobacterium necrophorum Not F. nucleatum
Y Ho, W Coman. Lemierre Syndrome—Who First Described It?. The Internet Journal of Otorhinolaryngology. 2009 Volume 12 Number 2.
An intraoperative photo showing the drainage of purulent materials.
Life threatening infection of the floor of the mouth
Infections spreading from infected lower molar
Mixed aerobes and anaerobes infections Including Staphylococcus aureus,
Enterobacteriaceae, Streptococcus, Bacteroides, Peptostreptococcus, Peptococcus, Fusobacterium
Risk factors for anaerobic pulmonary infections Aspiration of oropharyngeal secretions or gastric
contents Periodontal or gingival diseases / infections
Pneumonitis -> necrotizing pneumonia -> pulmonary abscess with our without empyema
Entry of enteric microorganism into peritoneal cavity through defect in intestinal wall
Perforated appendicitis, ruptured hollow viscus, ruptured diverticulitis Secondary peritonitis, intra-abdominal abscess
Hepatobiliary infections Chlolecystitis, ascending cholangitis
Polymicrobial infections Obligate anaerobes Bacteroides fragilis group, Bilophila wadsworthia,
Peptostreptococcus micros, Clostridium, Fusobacterium, Eubacterium spp.
Facultative anaerobes ( or aerobes? ) Escherichia coli, Streptococcus spp. Enterococcus
spp.
Pseudomembranous colitis ATB associated
http://pet-ct-kpc.blogspot.com/2012/09/pseudomembranous-colitis.html
Bacterial vaginosis soft-tissue perineal,
vulvar and Bartholin gland abscesses
Endometritis, pyometra
Salpingitis, tubo-ovarian abscesses
adnexal abscess pelvic inflammatory
disease
amnionitis septic pelvic
thrombophlebitis intrauterine
contraceptive device-associated infection
septic abortion postsurgical obstetric
and gynecologic infections.
Usually involve: Prevotella bivia, Prevotella disiens, Peptostreptococcus, Porphyromonas, Clostridium spp
??Bacteroides fragilis group?? -> less common Actinomyces spp., Eubacterium nodatum
associated with intrauterine device (IUD) Mobiluncus spp., Gardnerella vaginalis ->
bacterial vaginosis
Necrotizing fasciitis (Type 1 – polymicrobial) Myonecrosis / gas gangrene Clostridium perfringens
Melaney’s synergistic gangrene Anaerobic streptococci / Staphylococcus aureus Usually postsurgical
Bite wound infections Animal - Pasteurella multocida, Capnocytophaga carnimorsus
Human - Eikenella spp., pigmented Prevotella, Porphyromonas, Fusobacterium, Peptostreptococcus spp.
Fournier’s gangrene Synergistic gangrene involving perineum / scrotum Bowel/rectal flora - Bacteroides fragilis group,
Clostridium spp., Enterobacteriaceae, Enterococcus spp
Decubitus ulcer Bony prominent
Diabetes foot infection Vascular insufficiency
http://www.ijcasereportsandimages.com/archive/2013/002-2013-ijcri/013-02-2013-neogi/ijcri-013022013113-neogi-full-text.php
malignant neoplasms hematologic disorders
/ neutropenia organ transplant recent gastrointestinal,
obstetric, or gynecologic surgery
intestinal obstruction decubitus ulcers
dental extraction Newborn diabetes mellitus Postsplenectomy the use of cytotoxic
agents corticosteroids
Infection adjacent to a mucosal surface Foul-smelling discharge Necrotic gangrenous tissue Abscess formation? Infections related to tumors Infected thrombophlebitis – internal jugular v Chronic infection Pos Gram-stain but neg aerobic culture Mixed organism by gram stain
Brain abscess Dental infections Bite wound Aspiration pneumonia Lung abscess Bowel perforation Amnionitis Endometritis Septic abortion Tubo-ovarian abscess
Abscess around mouth Abscess around rectum Postsurgical infections Necrotic tumors Diabetic foot ulcer Decubitus ulcer
Surgery Wound opening – exposure to air / oxygen Debridement Incision and drainage Percutaneous drainage Vascular surgery
Antibiotic Usually empirical treatment Types of organisms ▪ susceptibility pattern – usually predictable
Penicillins Anaerobic Streptococcus Actinomyces Clostridium spp. (not C. difficile) destroyed by beta-lactamase ▪ Produced by most strain of anaerobic Gram negative
Cefoxitin Clostridium perfringens ( less active against other Clostridium)
▪ Not active against C. difficile
Bacteroides fragilis (resistance ~ 5 – 15%)
Beta-lactam/beta-lactamase inhibitors Amoxicllin/clavulanate Ampicillin/sulbactam Piperacillin/tazobactam Cefoperazone/sulbactam Active against most anaerobes including B. fragilis Not active against Clostridium difficile Not for CNS infections
Carbapenems Not active against Clostridium difficile
Clindamycin Bacteroides fragilis (resistant ~ 5 – 10%) Not active against Clostridium difficile
Metronidazole Active against Bacteroides fragilis and other
gram negative anaerobes Active against Clostridium difficile Not active against microaerophilic Streptococcus,
Propionibacterium acnes, Actinomyces spp
Macrolides Variable activity against Bacteroides fragilis Active against Clostridium perfringens ▪ Not active against Clostridium difficile
Vancomycin Active against Clostridium difficile Not active against Gram-negative anaerobes
Tigecycline Bacteriostatic
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