Gram + Cocci Flashcards
The cell wall of Gram + cocci is rich in _ ____- and poor in ______?
Their cell wall is rich peptidoglycan and lipid poor cell walls
Why Gram + cocci retain Blue color dung colorization, with crystal violet?
Their cell wall is rich peptidoglycan and lipid poor cell walls, thus the organism retain blue color of crystal violet during decolorization.
Why amino-glycoside is not effective against Gram + cocci?
Because they can’t transport through cell membrane.
The family Micrococcaceae has how many genera and what are they
Composed of three genera: Micrococcus, Staphylococcus and Planococcus.
The planococeus tolerate………
They are arrangedin _ _____-and produce a _ _______ pigment on nutrient agar.
What are two species of planococcus
tolerate 12 % NaCl.
They are arranged in tetrads and produce a yellowbrown pigment on nutrient agar.
Planococcus citreus and Planococcus halophilus.
Where do Staphylococcus habit-ate?
Which staph is most pathogenic
Habitat the skin and mucus membranes of man. Only Staphylococcus aureus is the most pathogenic
Why Steph sometime appears as g-ve?
T/F_ staphylococcus are non motile and non spore forming bacteria.
Young cocci stain stains strongly G+ve, on aging becomes G-ve.
. True
How can we differentiate staph from strep?
Steph are coagulase and catalase positive. Where street is negative for both enzymes.
What are staphylococcus diseases?
1 Skin: Stich abscesses, impetigo, furuncles, carbuncles,
2 Bacteremia due to Staphylococcus infection leads to acute mitral and aortic valve endocarditis, osteomyelitis and embolic pulmonary
3 food poisoning due production of entro-toxin particularly
4 Virulent factors of Staph.aureus: elaborate a variety of extracellular toxins including: hemolysin (alpha, beta and gamma), Coagulase,hyaluronidase, exfoliatin, lukocidin and lipases)
What are primary infection of Staphylococcus?
Furuncle and Carbuncle
Explain Furuncle?
Explain carbuncle?
The furuncle or boil is a superficial skin infection that develops in a hair follicle, sebaceous gland, or sweat gland. Furunculosis is often a complication of acne vulgaris.
Infection at the base of the eyelash gives rise to the common stye. The infected patient is often a carrier of the offending Staphylococcus, usually in the anterior nares.
Infection can spread from a furuncle with the development of one or more abscesses in adjacent subcutaneous tissues.
This lesion, known as a carbuncle, occurs most often on the back of the neck but may involve other skin sites. Carbuncles are serious lesions that may result in bloodstream invasion (bacteremia).
What is impetigo?
S. aureus is most often seen as a secondary invader in group A streptococcal pustular impetigo
Strains of S. aureus that produce exfoliatin cause a characteristic form called bullous impetigo, Bullous impetigo can be considered a localized form of scalded skin syndrome.
What are deep lesions of staphylococcus?
1 Acute osteomyelitis is primarily a S. aureus disease
2 Pneumonia and deep tissue lesions
3 Bacteremic spread and endocarditis
4 Scalded Skin Syndrome: Widespread desquamation in neonates is caused by exfoliatin producing strains. ‘
When does staphylococcus cause vomiting!
Ingestion of staphylococcal enterotoxin-contaminated food results in acute vomiting and diarrhea within 1 to 5 hours.
There is prostration, but usually no fever.
What is drug of choice agnat S, aureus?
Penicillins and cephalosporins are active against S aureus cell wall peptidoglycan
