AGENTS OF BONE MARROW INFECTION Flashcards

1
Q

what is Osteomyelitis?

A

An infection of the bone and bone marrow

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2
Q

how does osteomyelitis occur?

A

when bacteria are introduced to the bone tissue in the following manners: as an extension of a local soft-
tissue, urogenital, or respiratory-tract injury; carried via the bloodstream; surgery; an open
fracture; or intravenous drug use.

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3
Q

What is the most causative agent of osteomyelitis?

A

Staphylococcus aureus because it resides in the body and on the skin as normal flora and is
pathogenic when traumatically introduced into other tissues and the bloodstream

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4
Q

what is the most common bacterial species to cause osteomyelitis in sickle cell patients?

A

Salmonella species

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5
Q

what does Salmonella osteomyelitis involve?

A

the diaphysis, or shaft, of the long bones in
children

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6
Q

how does brucella species cause brucelliosis/osteomyelitis?

A

can infect humans via ingesting
undercooked meat or unpasteurized dairy, inhaling the bacteria, or traumatic entrance through the
skin and mucous membranes via injury

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7
Q

how does group B strep cause osteomyelitis?

A

seen in newborns who acquire
an infection from their mother during birth

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8
Q

how does group A strep (progenies) cause osteomyelitis?

A

Newborns and children may develop bone marrow
infections

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9
Q

what are the virulence factors of Brucella species?

A

not encapsulated,
they possess an antigenic
lipopolysaccharide outer surface. O-antigens on the surface of the organism allow for the bacteria
to invade and enter host cells for replication and survival. Complement does not easily bind to the surface of lipopolysaccharides, providing the bacteria the ability to evade host immune responses and proliferate.
ability to survive extreme temperatures and pH levels, allowing it to thrive in various parts of the body
and allowing infections to spread

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10
Q

what are sickle cell disease patients susceptible to with a Salmonella infection?

A

susceptible to
sepsis and osteomyelitis infections

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11
Q

what antigens aid in Salmonella species to adhere to its host?

A

Fimbriae and H antigens on the
outer surface of the bacteria
surface proteins and antigens including antiphagocytic proteins, capsular antigens, H flagellate antigens, and
immunogenic O antigens, prevent phagocytosis and complement-mediated lysis of bacterial cells.
Lipid A in the outer layer is released upon the death of the
bacterial cell and is the endotoxin responsible for the fever and shock associated with these
infections

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12
Q

what contributes to the virulence of S. aureus?

A

the organism’s rigid peptidoglycan cell wall and surface
capsular antigens
which inhibit phagocytosis and promote adherence to host cells.

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13
Q

what is the importance of techoic acids in the cytoplasm membrane and cell wall of S. aureus?

A

they promote adhesion, colonization, and
bacterial cell division in hosts

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14
Q

How does S. aureus evade phagocytosis?

A

Protein A facilitates biofilm formation and adhesion, and it binds to
receptors on host immunoglobulins

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15
Q

Fibronectin-binding
proteins present in methicillin-resistant bacteria strains also promote the formation of:

A

a biofilm,
which is described as a thin, slimy film of bacteria that adheres to the surface of host cells and
tissues

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16
Q

Cellular toxicity and destruction of host cells of S. aureus is achieved by:

A

by red blood cell toxic hemolysins,
white blood cell toxic leukocidin, and heat-stable enterotoxins.

17
Q

Enzymes produced by S. aureus also aid in:

A

the virulence of the bacteria in the human body by degrading the host’s response to an
infection, facilitating the spread of disease

18
Q

S. agalactiae contains:

A

a rigid cell wall with polysaccharide capsular antigens that inhibit
complement activation and prevent phagocytosis.

19
Q

group B streptococcus species produces:

A

C5a peptidase, a protein that deters complement and neutrophil chemotaxis, and participates in
adhesion and invasion of host cells

20
Q

Pore-forming hemolysin toxins in group B strep promote:

A

organism entry into
host cells and facilitate its survival.

21
Q

S. agalactiae organisms resist intracellular phagocytosis and
spread infection by:

A

the actions of the following cell surface proteins: C antigen, cell surface
penicillin-binding protein, and hyaluronidase

22
Q
A