NON-SPORE FORMING GRAM POSITIVE BACILLI Flashcards
• The genus Corynebacterium is a large diverse group of bacteria.
• There are more than___\ species in the genus, and at least____ are thought to be clinically significant.
80
50
Corynebacterium
• Corynebacteria can be divided into
non-lipophilic and lipophilic species
Fastidious, and slow growing
Requires exogenous lipids for enhanced growth
LIPOPHILIC
Non-fastidious organisms
Does not require exogenous source of fats
NON-LIPOPHILIC
Causative agent of diphtheria
CORYNEBACTERIUM DIPHTHERIAE
also known as Klebs-Loeffler Bacillus
Corynebacterium diphtheriae
non-motile, glucose & maltose fermenter
• nitrate reduction & catalase (+)
• urease -)
CORYNEBACTERIUM DIPHTHERIAE
DISEASE ASSOCIATION (Corynebacterium diphtheriae)
RESPIRATORY DIPHTHERIA
CUTANEOUS DIPHTHERIA
• Severe form of infection
This is the most severe form of infection caused by C. diphtheriae
• Exotoxin attacks mucus membranes resulting to inflammation and “pseudomembrane formation” of the pharynx
Respiratory diphtheria
• Characterized by neck swelling (Bull’s neck)
Respiratory diphtheria
• Necrotic lesions on the skin which are manifested on open wounds.
CUTANEOUS DIPHTHERIA
ANTIMICROBIAL AGENTS (Corynebacterium diphtheriae)
________
It is the drug of choice for C. diphtheriae since penicillin is a beta lactam
drug that affects/destroys/alters cell wall synthesis of the bacteria.
_______for Penicillin - sensitive individuals
PENICILLIN
ERYTHROMYCIN
LABORATORY DIAGNOSIS (Corynebacterium diphtheriae)
•_______ swabs of inflamed areas — Most commonly or routinely used sample in the laboratory.
•____ or ____ spx (cutaneous diphtheria)
Nasopharyngeal
Wound or skin
Stains (C diphtheriae)
• Appearance of pleomorphic appearance, with metachromatic granules (Babe’s Ernst - polymerized phosphates)
Gram staining and loeffler’s methylene blue stain
- visualized by Loeffler’s methylene blue
• On Gram stain, Corynebacterium are slightly curved, gram-positive rods producing the described ….
Chinese characters
club shape or coryneform or Chinese characters.
• Toxigenicity test for C. diphtheriae strains that are non-toxigenic
• The culture medium used here is Nutrient Agar that is melted and is mixed with a horse serum.
Elek test
• After incubation, we could observe precipitant lines with different strains
In-vivo testing: injection of C. diphtheriae animal (direct inoculation)
In-vitro testing - modified
Elek test
CULTURE (Corynebacterium diphtheriae)
SBA: Small zone of…
______ (enhances metachromatic granule formation) or_____
•_______ - Gray to black colonies
ß - hemolysis
Loeffler’s serum/ Pai agar
Potassium Tellurite medium
- a culture medium specific for C. diphtheriae
Black colonies with yellow halo
Tinsdale’s medium
• The genus contains 10 species.
LISTERIA MONOCYTOGENES
Listeria
Only_____ is considered an important human pathogen.
Recovered from animal products, such as raw milk, cheese, poultry, and processed meats.
Listeria monocytogenes
VIRULENCE FACTOR (Listeria monocytogenes)
induces phagocytosis through increased adhesion and penetration into mammalian cells
damages the phagosome membrane, effectively preventing killing of the organism by the macrophage.
PROTEIN p60
LISTERIOLYSIN O
CLINICAL INFECTIONS (Listeria monocytogenes)
•_______ is recognized as an uncommon but serious infection primarily of neonates, pregnant women, elderly adults, and immunocompromised hosts.
Listeriosis
DISEASE IN PREGNANT WOMEN
• During pregnancy,_____ is most commonly seen during the third trimester
• It has been postulated that _____is responsible for spontaneous abortion and stillborn neonates.
listeriosis
L. monocytogenes
LABORATORY DIAGNOSIS (Listeria monocytogenes)
CULTURAL CHARACTERISTIC
• Grows well on___ and ____
• Prefers a slishtly increased carbon dioxide (CO2) —Slight capnophilic
• Growth occurs over a wide range (_____ to ____)
SBA and chocolate agar
0.5°C - 45°C
Because L. monocytogenes grows at 4°C, a technique called _____may be used to isolate the organism from clinical specimens.
COLD ENRICHMENT
In wet mount preparations, exhibits tumbling motility
• In motility medium, the characteristic “inverted Christmas tree/umbrella-like” pattern incubated at room temperature (22°C - 25°C) but not at 35°C.
L. monocytogenes
A more pronounced CAMP reaction is seen with L. monocytogenes when_____ is used in please of Staphylococcus aureus
Rhodococcus equi
Produces a “block” type hemolysis with the CAMP test.
at some point it will be considered as cryophiles, as it grows in a temperature of 4°C
Monocytogenes
PATHOGENICITY TEST
• Organism suspended in sterile water
2 or 3 drops are inoculated in the conjunctival sac of a rabbit’s eye
(+) test: purulent conjunctivitis
OCULAR TEST OF ANTON
GENERAL CHARACTERISTICS
There are 3 species in the genus
• is the only species in the genus known to cause disease in humans
• Occupational exposure (work involves handling fish)
ERYSIPELOTHRIX RHUSIOPATHIAE
Also known as Butcher’s disease
Erysipelothrix rhusiopathiae
• The usual route of infection is through cuts or scratches on the skin
• The organism is resistant to salting, pickling, and smoking.
Erysipelothrix rhusiopathiae
CLINICAL MANIFESTATIONS (Erysipelothrix rhusiopathiae)
• E. rhusiopathiae produces three types of disease in humans:
________
Which is a localized skin disease, cutaneous infection of hand and fingers
________
Which is often associated with endocarditis
____________
ERYSIPELOID
SEPTICEMIA
DIFFUSE CUTANEOUS INFECTION
H,S (+): The only positive in gram (+) bacilli is
E. rhusiopathiae
Gelatin stab: TEST TUBE BRUSH APPEARANCE
• Or inverted Christmas tree or umbrella like, it exhibits a test tube brush appearance.
Erysipelothrix rhusiopathiae
• Also known as DODERLAIN BACILLUS
LACTOBACILLUS ACIDOPHILUS
• Flora of the mouth, Gl tract, vaginal canal
If found in the mouth, it is called______, while if found in the vaginal canal, it is called______.
Buas
Doderlain
• Non-pathogenic, rare cause of bacteremia
• Helps maintain acid-environment produce large amount of lactic acid
Grows at pH 3-4
LACTOBACILLUS ACIDOPHILUS
LABORATORY DIAGNOSIS (Lactobacillus acidophilus)
Gran stain: motility
Catalase reaction
Media
• Gram +, non-motile
• Catalase, H2S & bile-esculin (-)
Grows at: TOMATO JUICE AGAR
Formerly H. vaginalis
• May cause neonatal sepsis and postpartum bacteremia
• Media:______- BEST!
GARDNERELLA VAGINALIS
Human Blood Tween Agar (HBT)
LABORATORY DIAGNOSIS (Gardnerella vaginalis) Vaginitis
• Sniff’s test:______ (+):_____
• Clue cells on Paps
Are squamous epithelial cells. Inside the cytoplasm of the cells, there are bacteria.
These are preferred as clue cells.
discharge + 10% КОН
Fishy amine odor
NOCARDIA
Specifically,_______
PARTIALLY ACID FAST - UNIQUE CHARACTERISTIC
Morphology - long thin, branching gram (+) bacilli
Grows well at SDA (inhibited by chloramphenicol)
______Agar
Growth enhances at 10% CO, for 3 days - 4 weeks
Colonies -….
Resembles MYCOBACTERIA
Nocardia asteroides
Sabouraud Dextrose
waxy, bumpy, velvety, yellow orange colonies
Nocardia is inhibited by_____
chloramphenicol
Nocardia
Growth enhances at 10% CO2 for_____
3 days – 4 weeks
● Colonies– waxy, bumpy, velvety, yellow orange colonies
Nocardia
