Anaerobic Bacteria I and II Flashcards
Name the Clinically important Anaerobic Gram Positive Cocci:
- where does it colonize?
- name of its infections
- how is it treated
Peptostreptococcus
○ Found on Skin and Mucosal Surfaces ○ Polymicrobial infections: sinusitis, pulmonary infections, brain abscess, endometritis, pelvic abscess, cellulitis, nec fasc, osetomyelitis ○ Treatment: PCN (but usually in combination therapy)
Name the 4 clinically important Anaerobic Non Spore Forming Gram Positive Rods (GPR)?
- where do they colonize
Actinomyces – A. israelli – colonize oropharynx, GI, female GU
PCN , erythromycin, c
Lactobacillus – mucosal surfaces
Mobiluncus – colonizer of the vaginal tract
Proprionibacterium – mucosa and the skin
Actinomyces israelli -
- Class of organism
- manifestations
- Macroscopic colony appearance
- Tx
Anaerobic Non Spore Forming Gram Positive Rods
Cerebral
Cervico-facial – indurated lesion at angle of the mandible (“Woody firbrosis” – can be mistaken for malignancy)
Thoracic – patients with compromised gag reflex aspirate oropharyngeal content; get PNA which can penetrate into chest wall
Abdominal - appendicitis
Pelvic: classically associated with copper IUDs
“Molar tooth” appearance of the colony
Treat: PCN; erythromycin, clindamycin
Lactobacillus
- Class of organism
- manifestations
- Unique gram stain appearance
- Tx
what is it resistant to
Anaerobic Non Spore Forming Gram Positive Rods
General: usually isolates are clinically insignificant
□ Septicemia in compromised patients
□ Endocarditis in persons with valve abnormalities
Stain: Classic Appearance —- elongated GPRs
Treat: PCN (+/- aminoglycoside)
□ Resistant to vancomycin
Mobiluncus
- Class of organism
- manifestations
- Tx
what is it resistant to
Anaerobic Non Spore Forming Gram Positive Rods
Colonizer of the vaginal tract
§ “Associated with bacterial vaginosis”
□ Unclear if this is the cause. May just be a marker for BV
Treatment of BV with metronidazol, which mobiluncus is resistant to
Proprionibacterium
- Class of organism
- manifestations
- unique gram strain appearance
- Tx
what is it resistant to
Anaerobic Non Spore Forming Gram Positive Rods
§ Most commonly isolated anaerobe
§ Cause of Acne
Can also cause infections with indwelling foreign hardware (valves, joints, indwelling vascular catheters)
§ Culture: clumping of short GPRs
Treat Benzoly peroxide (topical); PCN, tetracyclines, erythromycin, clindamycin
name the two anaerobic Gram Negative Rods
○ Bacteroides fragilis – colon
○ Fusobacterium nucleatum -- oropharynx, GI, GU
Bacteroides fragilis
- Class of organism
- Virulence
- manifestation
- Tx
what is it resistant to ?
anaerobic Gram Negative Rods
- Virulence:
LPS but not an endotoxin
Polysaccharide capsule prevents phagcytosis
forms abscess
Manifestations: Abscess - (abdominal, PID, endometritis, surgical wound infections, skin and soft tissue infections)
Treat: Metronidazole + abx for other organisms
Resistance: PCN (due to beta lactamases)
Fusobacterium nucleatum
- Class of organism
- unqiue appearance on gram stain?
- manifestation
- Tx
anaerobic Gram Negative Rods
Gram stain – very long thin (fusilli?) GNR
Oropharyngeal infections: • Molar tooth abscess • Peritonsillar abscess • Perimandibular space infections: Can move into Pharyngeal spaces -- retro and lateral pharyngeal
Jugular venous thrombophleitis (Lemierre’s syndrome):
tx: Beta Lactam + Beta Lactamase Inhibitor
Ampicillin - sulbactam > amoxi-clavulonate
+ Debridement of abscess
Describe the pathenogenesis of :
Jugular venous thrombophleitis (Lemierre’s syndrome)
Classically caused by Fusobacterium
Pharyngitis – peritonislar abscess – pharyngeal spaces – thrombophlebitis of IJV
Clots may embolize to the lungs
Anaerobic Spore Forming Gram Positive Rods (GPRs)
- name the genus and the 4 clinically important species
- What is the primary virulence factor ?
Genus: Clostridium
Species: C. dif, C. Perfringes, C. Tetani, C. botulinum
Virulence: Spore Forming
Clostridium Tetani:
- Class of organisms
- how is it transmitted?
- Name the Toxin? – what does it do?
- Characteristic finding on physical exam?
- Spore Froming GPR
- Transmitted through puncture – nails, splinters, IVDU
- Tetanus Toxin: an A-B Toxin
B binds
A internalized; inhibits release of GABA and Glycine
Manifestations of Tetanus:
Diagnosis of Teatnus:
Treatment:
Manifestations;
Generalized Tetanus – lockjaw, opisthotosis, autonomic instability (Sweating, arrythmia, fevers, tachy), respiratory failure — SPASTIC PARALYSIS
Localized, Cephalic and Neonatal Tetanus
Diagnosis: Spastic paralysis
Opisthotosis – Pathomneuomonic with Tetanus
Treatment: Metronidazole
secondary : PCN, but this can inhibit inhibitory synapses and make things worse
Wound cleaning, airway management
C. Botulinim
- Class of organism
- where is it found
- What is the toxin and its effect
- Characteristic finding on Physical exam
- What are the types of botulinum illness
Anaerobic Spore Forming GPR
- Found in soil, sediment, vegetables, home canned foods, with alkaline pH, seafood
Botulin Toxin:
- inhibits release of Ach at the NMJ
- FLACID PARALYSIS
Types of illness: foodborne, wound, infant botulism, Inhalation botulism (bioterrorism)
What are the clinical manifestations and cardinal signs of Botulism ?
- compare to Guillane Barre
- compare to polio
Botulism:
Cranial Nueropathies with symmetric descending paralyiss, progressing to resp failure
- NO FEVER
- NO SENSORY DEFICITS
Guillan Barre – ASCENDING paralysis + sensory deficits
Polio - FLaccid paralysis + FEVER
Botulism:
- Diagnosis
- Treatment
Diagnosis: Physical Exam
Culture and Microscopy are not useful
Treatment: Metronidazole
Trivalent Botulinum anti-toxin
Keep food at acid pH and below 4C
Kill bacteria at 80C
Clostridium Perfringes:
- Class of organism
- Where is found ?
- What is unique about its culture?
- Toxins ?
- What disease can it cause ?
- Anaerobic Spore forming GPR
- Found in soul, water, Gi of humans and animals
- Culture: Double zone of Hemolysis
- Toxins: • α, β, ε, ι toxins; enterotoxin
Diseases: Food poisoning Soft tissue infection: Myonecrosis (Gas Grangrene) Nec fash, cellulitis Bacteremia
-
If you see SubQ emphysema on any imaging, what should you immediately think?
Anaerobic infection such as C. perfringes gas gangrene
Treatment and Diagnosis of C. perfringes:
- what is characteristic about the microscopy
-Treatment
– will see no WBC or RBC in the infection (bc its so rapid?)
- Treatment:
Surgical Debridement
ABX: PCN + Clindamycin (to inhibit toxin synthesis)
Clostridium Dificile:
- What class of organism
- whwere is it found
What are its toxins and what do they do?
What strain is assocaited with CA c. dif colitis
- Anaerobic GPR, spore forming
- colonizes the GI tract in a small number of healthy people
- Toxins: Enterotoxin, Cytotoxin — damage colonic tissue, form pseudomembrane plaque
NAP 1 strain
C. Dif;
- What is the mechanism of Disease ?
- What are the manifestations of disaese?
-
mechanism of Disease;
- FQs, Clinda, and Cephalosporins can suppress the normal flora
- Allow for overgrowth of C. Diff
Manifestations:
- diarrhea
- Psuedomenbranous colitis — Toxic megacolon — susceptible to perforation — sepsis and death
High relapse rate
Diagnosis of C. dif
Treatment of C. dif
Prevention
- Dx: PCR Amplification of Toxin genes distinct Smell (tyrosine fermentation)
- Treatment:
- nonsever disease: Metronidazole
- Sever diasese: Oral Vanc +/- IV metronidazole
- Fecal transplant
Prevention: have to wash hands
alcohol does not kill the spores
