Primary ecological niche: anterior narex
- 20% of people are persistent carriers. 30% are intermittent carriers.
can colonize the skin and GI as well.
Gram positive cocci in grape like clusters. Virulence factors: Protein A - binds Fc-IgG prevent complement fixation and phagocytosis. also, has catalase. bad strands of staph have coagulase. they can form fibrin clots around themselves, and this may form abscesses.
potential to cause inflammatory disease, toxin mediate disease - toxic shock syndrome, scaled skin synrome, rapid onset food poisoning.
TSST is a superantigens that binds to MHC II and T cell receptor --> polyclonal T cell acivation. leads to fever, vomiting, desquamation, shock, end-organ failure. TSST is an exotoxin.
when multiplying, produces different toxins than when quiescent.
diagnosis based on detection of pathogen antigens, or of the patient's own antibodie response to pathogens.
antigens and antibodies can be easier to detect than direct observation or culture.
methods are very sensitive and specific, often quantitative, technically easy. antigens and antibodies are produced in large quantities and can be found in body fluids.
antibody detection: immunodiffusion, agglutination, RAST, ELISA, western blot.
antigen detection - agglutination, RIA, ELISA, western blot
pay attention to size, color, morphology, pattern, distribution, arrangement on the body. progression of rash. presentation related to fever.
age of patient, season, travel history, geographic location, exposures, immunizations and history of childhood illnesses, immune status, sex contacts.
cough, coryza, conjunctivtis (three C's). fever, light sensitivity, myalgia, sore throat. APPEAR MISERABLE.
rash: usually 3-5 day after first signs of being sick. may last 4-7 days. usually starts on the head and spreads to other areas, moving down the body. rash may appear as fat, discolored areas (macules), and solid, red, raised areas (papules) that join together (become confluent).
enanthem: KOPLICK spots = tiny red or white spots with red halo on buccal mucosa.
acute serious illness: sudden onset of high fever, chills, ehadache, muscle ache, vomiting, diarrhea.
next 24-48 hrs: patient's develop erythroderma (sunburn like diffuse reddening of skin).
hypotension, conjunctival hyperemia (red eyes - more blood flow to the eyes), STRAWBERRY TONGUE, and multiorgan disfunction - including rapidly progressive renal failure.
other manifestations: peripheral cyanosis and edema, pulmonary edema, myocarditis, mental status changes.
CONSIDER IN PATIENTS WITH FEVER AND ERYTHRODERMA. or in patients with fever and hypotension.
during recovery: full thickness desquamation of the skin.
tick-borne (American dog tick) illness caused by gram negative INTRACELLULAR bacterium Rickettsia ricketsii (cannot see on gram stain).
prevalent in south central US.
majority of cases between april and october. suspect it in males <15 yo.
prodrome: fever, nausea, vomiting, ab pain, HA, malaise, photophobia.
following exposure, bacteria multiply iwthin endothelial cells of small vessels and disseminate in bloodstream --> leads to endothelial cell inury, thrombosis and capillary leak --> edema and petechiae.
classic rash: begins 2-5 day as blanching macules and papules 2-3 mm on wrists and ankles (petechiael).
rash then spreads centripetally (INWARD) to arms, thighs, trunk.
eventual involvement of PALMS AND SOLES.
classic rash only seen in 35-60%. 10-15% never have rash.
infects 300-500 million persons worldwide annually. causes 1-3 million deaths annually. plasmodium ____. symptoms: headache, fever, fatgiue, pain, back pain, chills, sweating, dry cough, spleen enlargement, nausea, vomiting. obligate intracellular gram negative bacteria.
transmitted by fleas, lice, mites, ticks.
outbreaks during war and natural disasters.
symptoms: fever, headache, malaise, rash (maculopapular, petechiael, vesciular)
DX: PCR, immunohistochemical analysis of tissue, culture.
yersinia pestis. gram negative rod. with a capsule.
reservoirs: rats, gerbils, squirrels, field mice.
transmission: via flea from one of these animals. human to human if serious bronchopneumonia from yersinia.
fever, hypotension (septicemic)
fever, very swollen lymph nodes in axilla or groin. may be followed by generalized spread and multisystem illness (bubonic). severe bronchopneumonia. high mortality without treatment.
diagnosis: use gram, giemsa or fluorescent stain from lymph node aspirates. can be cultured as well.
treat with: streptomycin, DOXYCYCLINE, quinolones.
prevention - quarantine, vaccines, rodent control, chem-prophylaxis, isolation.
go from portal of entry to lymph nodes, and bloodstream. can survive for prolonged periods in the liver, spleen, bone marrow, lymph nodes. chronic granulomatous infection occurs.
infection may be subclinical, or gradual development of fever, malaise, sweats. undulant fever described (intermittent). enlarged lymph nodes, hepatitis may occur, osteomyelitis and endocarditis rare.
infection USUALLY resolves, but some may develop chronic infections with fatigue, intermittent fever, waxing and waning symptoms.