Chapter 23: Microbial Diseases of the Cadriovascular & Lymphatic Systems

cardiovascular system

circulates blood through the body’s tissues

• includes the hearts & associated arteries, veins, & capillaries

• delivers substances to & removes substance from the cells

lymphatic system

plasma leaves blood capillaries to become interstitial fluid

lymph capillaries

transport interstitial fluid (lymph) to lymph vessels (lymphatics) & lymph nodes

• picks up microorganisms & infectious agents

lymph nodes contain

fixed macrophages, B cells, & T cells

buboes

swollen lymph nodes

septicemia

acute illness due to the presence of pathogen or their toxins in the blood

sepsis

condition in which the body responds improperly to an infection; systemic inflammatory response syndrome (SIRS)

lymphangitis

inflamed lymph vessels

severe sepsis

decreased blood pressure & dysfunction of at least one organ

septic shock

sepsis & uncontrollable decreased blood pressure

gram-negative sepsis

• endotoxin shock; LPS cause a severe drop in blood pressure

• antibiotics can worsen the condition by killing bacteria

• treatment involves neutralizing the LPS components & inflammatory-causing cytokines

• Klebsiella spp., E. coli, & Pseudomonas aeruginosa are most frequently involved

gram-positive sepsis

• potential exotoxins that cause toxic shock syndrome

• hospital acquired infections

endocarditis

inflammation of the endocardium (innermost layer of tissue that lines the heart’s chambers & valves)

subacute bacterial endocarditis

• impairs the function of the heart valves

• alpha-hemolytic streptococci from an oral or tonsil infection

acute bacterial endocarditis

caused by Staphylococcus aureus

pericarditis

• inflammation of the sac around the heart

• streptococci

bacteria that causes plague

Yersinia pestis

plague vector

the rat flea

plague is endemic to

rats, ground squirrels, & prairie dogs

morphology of Yersinia pestis

gram-negative rod & capsule; cell membrane, cell wall, slime envelope, pPCP1 plasmid, pCD1 plasmid, pMT1 plasmid, ribosomes, cytoplasm, chromosomal DNA, bi-polar staining

bubonic plague

bacterial growth in the blood & lymph

• most common form of plague; 50-75% mortality rate

septicemic plague

septic shock due to bacteria in the blood

pneumonic plague

• bacteria in lungs

• easily spread by airborne droplets

• near 100% mortality rate

• antibiotic prophylaxis for exposure

plague fleas

bite the host, where its blood is regurgitated into the host; bacteria enters bloodstream & proliferate in the lymph tissue, causes buboes

plague infection pathology

1. plague bacteria evade antibiotics (pla, v-antigen, & capsule)

2. invading macrophage through membrane receptors (Ysc & Yops)

3. bacteria use intracellular proteins to protect themselves & multiply (capsule & other proteins)

patient with plague

usually dies of endotoxin shock

lyme disease bacteria

Borrelia burgdorferi

lyme disease

most common tickborne disease in the US

reservoir for lyme disease

field mice

vector of lyme disease

ticks

lyme disease morphology

looks like a squiggly line with a membrane

phase 1 of lyme disease

bull’s eye rash; flulike symptoms

phase 2 of lyme disease

irregular heartbeat, encephalitis, facial paralysis, memory loss

phase 3 of lyme disease

arthritis due to immune response

treatment for lyme disease

antibiotics; more difficult to treat in later stages