ID Exam 1 Flashcards
Systemic inflammatory response syndrome (SIRS) criteria
- Tachycardia (> 90BPM)
- Tachypnea (> 20 RPM)
- Fever ( >38C or <36C)
- Increased/decreased WBC count (> 12,000 or <4,000 or >10% immature forms (bands))
Normal WBC count
4,500-11,000 cells/mm3
(represents total number of WBC - neutrophils, lymphocytes, monocytes, eosinophils, basophils)
Non-infectious causes of elevated WBC count
steroids, leukemia, stress, pregnancy, RA
Percentage of mature neutrophils (PMNS, polys, segs) in normal WBC differential
36-73% (most common WBC)
Percentage of immature neutrophils (bands) in normal WBC differential
0-5%
(increased during infection = “left shift”)
Leukocytosis is associated with _________ infections (as opposed to lymphocytosis)
bacterial
Lymphocytosis is associated with _________, _________, and __________ infections
viral, fungal, tuberculosis
What is leukocytosis?
an increase of neutrophils +/- bands
What is leukopenia? It might be a sign of what?
abnormally low WBC, which may be a sign of overwhelming infection
ANC =
WBC x (% segs + % bands/100)
Neutropenia = ANC < ________
500 cells/mm3
(or if ANC is expected to decrease to < 500 in the next 48 hours)
ANC < 500 is associated with a substantial risk of __________
INFECTION (especially by opportunistic pathogens)
ESR normal values
0-15 mm/hr (males)
0-20 mm/hr (females)
CRP normal value
0-0.5 mg/dL
Procalcitonin normal level
<0.05 mcg/L
Procalcitonin is _____ specific for bacterial infections than ESR and CRP
more
PCT < 0.25mcg/L =
low risk of infection
PCT > 0.5 mcg/L =
antibiotics should be continued
Serial measurements of PCT every 1-2 days are useful for what?
to assess response to therapy and when to discontinue antibiotics
Allergenicity of B-lactams
They acylate host cell proteins which raise antibodies that result in an allergic reaction
What chemical feature of penicillins confer resistance to degradation under acidic conditions?
The electronegativity of the substituent on the side chain carbonyl - if it reduces nucleophilicity/takes electron density away from carbonyl oxygen atom = stabilization
Which has a thicker peptidoglycan cell wall?
Gram (+)
In which type of bacteria are beta-lactamases confined to the periplasmic space?
Gram (-)
In Gram (-) cells, peptidoglycan is bridged between the terminal D-Ala and the ______ residue
DAP (mesodiaminopimelic acid) residue