ID Lecture 1 Flashcards
commensal definition
a microorganism that is a normal inhabitant of the human body; either the microbe or host derives benefit; neither is harmed.
pathogen definition
A microorganism capable of causing disease. Includes commensals and non-commensals
commensal pathogen
a microorganism that is commonly fund within the indigenous microbiota and can cause disease in normal hosts
obligate pathogen
a microorganism that must produce diseases to transmit and thereby survive evolutionarily
zoonotic pathogen
a microorganism that is a colonizer or pathogen in animals and that can be transmitted to humans
environmental pathogen
a microorganism capable of causing disease that is transmitted to humans from an environmental source such as soil or water
what temp is considered a fever?
> 38 C, >100.4 F
Which drugs may cause drug-induced fevers?
beta lactams, sulfonamides, anticonvulsants
what are other non-infectious causes of fevers?
malignancies, blood transfusions, auto-immune disorders
what may cause false negatives for fever?
tylenol, nsaids, aspirin, steroids, hypothermic infection <36 C or 96.8F
What are the 4 criteria for SIRS? (systemic inflammatory response syndrome)
HR > 90bpm, RR >20rpm, Fever >38 or <36, WBC>12000 or <4000
normal WBC count
4.5-11 (x10^9) or 4500-11000 cells/mm^3
what non-infectious causes can elevate WBC?
steroids, leukemia, stress, RA, pregnancy
what type of WBC increases during infection?
immature neutrophils (bands)
what do increased neutrophils and bands indicate?
bacterial infection; increased bone marrow response to infection
What does low WBC indicate?
overwhelming infection; poor prognosis
What does lymphocytosis indicate?
B cells and T cells (indicate viral, fungal, and TB infections)
mature neutrophils
segs, polys
What is neutropenia?
ANC <500 cells/mm^3, profound neutropenia 100 cells/mm^3
when should you start to worry about infection risk?
ANC <1000
ESR
erythrocyte sedimentation rate
CRP
C reactive protein
what happens to ESR and CRP during infection
elevates during inflammatory processes
normal EsR and CRP
ESR: 0-20 (mm/hr) females 0-15 (mm/hr) males
CRP: 0-0.5 mg/dL
PCT
procalcitonin (PCT)
normal PCT level
<0.05 mcg/L,
<0.25 = low risk of infection
>0.5 mcg/L = continue abx
PCT monitoring
every 1-2 days
how many of SIRS criteria must be present to diagnose with SIRS?
2 out of 4
