Gram positive rods Flashcards
Gram positive rods
- Corynebacterium
- Bacillus
- Cutibacterium
- Clostridium
- Actinomyces
- Nocardia
- Listeria monocytogenes
- Erysipelothrix rhusiopathiae
- Gardnerella vaginalis
- Lactobacillus
- Bifidobacterium
- Eubacterium
Corynebacterium
Catalase positive
They are lipophilic so some species may grow better on BLOOD than choc
Small gram positive rods
Lipophilic Corynebacterium spp.
C. jeikeium (wound infection)
C. urealyticum (UTI)
C. kroppenstedtii (mastitis)
C. kroppenstedtii (mastitis)
C. accolens
C. afermentans
C. tuberculostearicum
C. resistans
C. sputi
C. lipophiloflavum
C. macginleyi
Which Corynebacterium spp causes UTI in immune-competent hosts?
C. urealyticum
Which Corynebacterium spp causes wounds/abscesses in immune-competent hosts?
C. jeikeium
Which Corynebacterium spp causes breast abscesses in immune-competent hosts?
C. kropenstedtii
Which Corynebacterium spp causes ear infections in immune-competent hosts?
Corynebacterium otitidis
Which Corynebacterium spp causes respiratory/cutaneous infections in immune-competent hosts?
Corynebacterium diptheria
Why is it difficult to distinguish Corynebacterium from other flora and how to determine it is causing an infection?
It is a normal commensal, grows with other flora and multiple positive cultures or an abundance of Corynebacterium are required to establish it as the disease causative agent
Diseases caused by Corynebacterium in immune-compromised hosts? (3)
- CLABSI- central line bloodstream infection due to central venous catheters
- CSF shunt or drain infection (could be a contaminant, since it is a skin commensal)
- Respiratory tract infections
Which Corynebacterium causes diphtheria?
C. diphtheriae
rarely by C. ulcerans/C. pseudotuberculosis
Diphtheria symptoms
spread by respiratory droplets (very contagious)
toxin mediated
pseudo membrane on throat
causes sore throat, fever, swelling of lymph nodes, may affect swallowing
Complications: difficulty breathing, myocarditis, nerve damage, kidney failure
Which media selects for C. diphtheriae? (3)
Löffler agar
Cystine tellurite blood agar
Tinsdale agar
Name of the test for diphtheria toxin?
ELEK test (only performed in public health labs)
immunodiffusion test
There is a filter paper with diphtheria antitoxin, immunoprecipitation appears if the strain carries the toxin
Bacillus
Paenibacillus
Geobacillus
large colonies.
Beta hemolytic (except B. anthracis)
Catalase positive
Bacillus cereus
toxin-mediated food poisoning (organisms not isolated, only toxin)
Associated with contaminated wounds, eye infections, IVDU, and neonates
may cause systemic disease in the immune compromised
Actinomyces spp.
Anaerobic
molar tooth colonies, branching or rods, not acid fast
usually cause abscess with purulent exudate (pus) in head and neck regions
Also associated with IUD pelvic infections (usually normal flora, but in large quantities may cause disease)
associated with poor dental hygiene
abscess contain bacteria aggregates termed “sulfur granules”
Nocardia
Aerobic
Look like Actinomyces, but these are modified acid fast positive
Grow on Löwenstein-Jensen (LJ) medium
distributed in water, soil, dust, and decaying vegetation
(not a commensal)
causes disease in immunosuppressed: skin, lungs, or brain
Erysipelothrix rhusiopathiae
Gram positive rod, but may decolorize
may cause swine erysipelas (erysipeloid rash/cellulitis) in people who work with farm animals
Rash is very faint and localized (looks like red scratches)
this might cause endocarditis and acute septicaemic disease in immunocompromised people
Rash is very faint and localized (looks like red scratches)
Listeria monocytogenes
Foodborne pathogen that survives refrigeration temperatures
found in dairy products, vegetables, and cooked meats:
queso fresco, milk, ice cream, lunch meat
may spread hematogenously to:
1. liver (pyogranulomatous hepatosplenitis)
2. brain (meningitis) neonates and older adult patients
3. bloodstream (bacteremia)
4. placenta (may cause stillborth or neonatal infection)
