Patcharasarn Linasmita MD HRH Princess Maha Chakri Sirindhorn Medical Center

Srinakharinwirot University

Aerobes Anaerobes Fastidious Not reported in conventional (aerobic) culture

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

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

Capable of anaerobic metabolism? Anaerobic respiration fermentation

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

http://www.ncbi.nlm.nih.gov/books/NBK7638/figure/A1030/

http://www.ncbi.nlm.nih.gov/books/NBK7638/figure/A1041/

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

http://classconnection.s3.amazonaws.com/431/flashcards/1239431/jpg/actinomyces1331506946657.jpg

http://history.amedd.army.mil/booksdocs/wwii/communicablediseasesV5/chapter1figure1.jpg

http://www.hindawi.com/journals/crim/2010/340109/fig1/

http://pathmicro.med.sc.edu/mycology/actino-lump2.jpg

Sulfur granule

r granule

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

http://1.bp.blogspot.com/_Uf5f7SzC8gE/TRylCv-sBUI/AAAAAAAABfQ/GpUg2VoqoEA/s1600/dynamic+urti.jpg

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

Superoxide dismutase Relatively aerotolerance

Beta-lactamase Hydrolysis of beta-lactam antibiotics

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

Brain abscess Subdural abscess Epidural abscess (infrequent) Meningitis (infrequent)

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)

Anaerobes – rare!!!! Complications of shunt (shunt infections)

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

http://blog.timesunion.com/mdtobe/files/2013/12/Lemierre-Syndrome-2.jpg

http://www.nejm.org/doi/full/10.1056/ENEJMicm030003

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

http://www.aafp.org/afp/1999/0701/p109.html

http://healthwise-everythinghealth.blogspot.com/2010/08/answer-to-medical-challenge.html

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.

https://en.wikipedia.org/wiki/Gas_gangrene

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

http://www.documentingreality.com/forum/f149/pressure-ulcers-aka-decubitus-ulcers-123260/

http://janmrtelobainfo.ge/?page_id=5555

Diabetic foot ulcer

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

Chloramphenicol Good in vitro activity against anaerobes experience of using this drug in intra-abdominal

sepsis was disappointing Side effect: aplastic anemia