Blood stream infections Flashcards
5 factors that help contribute to sepsis?
- Chemo and radiation
- Corticosteroids and immunosuppressants
- People are getting older
- Invasive devices like catheters and surgical prostheses
- Certain antimicrobials for non-bacterial infections that allow for potential resistance
Compare bacteremia vs. septicemia:
Bacteremia: viable bacteria within liquid component of the blood
Septicemia: same as bacteremia but implies presentation of CLINICAL MANIFESTATIONS associated with bacteria in bloodstream
Order of bloodstream infections (1-4); what is the timing of this?
- Bacteremia
- Sepsis: infection with a systemic response
- Severe sepsis: maybe renal failure, hypotension, DIC, confusion
- Septic shock: body shuts down and you have ORGAN HYPOPERFUSION and lactic acidosis;
could be 4 hours!!
SIRS is; what is sepsis equal to?
an inflamm state of the whole body without proven source of infection;
SIRS and proof of BSI
SIRS can lead to; besides BSI, what can cause SIRS?
MODS;
- severe trauma
- Complication of surgery
- Burns
- Acute pancreatitis
- Immunodeficiency
Some clinical features of sepsis include; what three things can lead to acute organ dysfunction?
fever, rapid pulse and breathing, nausea, diarrhea, confusion;
- systemic inflammation
- coagulation
- impaired fibrinolysis
_____ plays most critical role in mediating SIRS; this can lead to what being released?
TLR-4; release of proinflamm mediators like TNF-alpha, IL1, IL6
What can serve as the initial trigger for excessive release of cytokines in endotoxic shock? Consequence?
LPS of gram neg bacteria;
DIC (microthrombi that can reduce blood flow and damage body’s organs) and defective clotting
Cascade of inflamm and coag during sepsis can be blocked by what?
Activated protein C; recombinant form has been approved to treat sepsis
Types of bacteremia (TIC):
Transient (chewing, brushing teeth, surgery involving non-sterile sites, aka procedures involving contaminated or colonized skin and/or mucosal surfaces and at onset of acute bacterial infections);
Intermittent (extravascular infection which provides portal of entry for bacteria; think of abscesses, cholangitis, pneumonia, osteomyelitis, meningitis or pyogenic arthritis);
Continuous: bacterial endo and other endovascular infections (low numbers of bacteria)
Examples of intravascular infections include
- Infective endocarditis (acute means death in several days to less than six weeks; subacute is 6 weeks to 3 months; chronic is later than 3 months)
- Mycotic aneurysm (endo cells lining arteries lead to seeding of the organism, think staph, strep, salmonella)
- Thrombophlebitis (damage to endo cells lining a vein; results in clot formation and seeding of clot by organisms, think catheter)
Steps of infective endocarditis
- Damage to cardiac endothelium
- Deposition of platelets and fibrin
- Organisms in bloodstream can stick
- Another layer of 2
- Bacterial multiplication
- Vegetation formation
CRBSI is
due to catheters and it being used for too long, moved around, contaminated, poor aseptic technique, location
Five sources for CRBSI
- Insertion site
- Catheter hub
- Hematogenous seeding of catheter
- Contamination of infusate
- Hands of health care personnel
One main organism causing catheter-related infections:
Coagulase-neg staphylococci
Two organisms associated with neoplasms include:
- Clostridium septicum
- Streptococcus bovis
(maybe campylobacter, aeromonas hydrophilia, plesiomonas shigelloides)
What is most commonly used to dtect BSI’s?
Blood cultures (slow)
Number of blood culture sets corresponds with
x2 the number of bottles (ie two sets = four bottles); aerobic bottle and anaerobic bottle in the set, and three sets means 99% bacteremia detected (80, 90 with 1 and 2 sets)
For a blood culture, what must be done after you give iodine?
Ideally, let it dry and then perform venipuncture to get your sample
What helps with differentiating infectious SIRS from noninfectious SIRS? What is this stimulated by?
Procalcitonin level;
bacterial products like endotoxins/LPS, and cytokines (IL1, IL2, IL6, TNF-alpha)
Intravascular infections are; extravascular infections are
within the cardiovascular system; bacteria that enter the bloodstream through the lymphatic system from another site of infection
SIRS manifested by at least two of the following four:
- Hyperthermia or hypothermia
- Tachycard
- Tachypnea/hyperventilation
- Leukocytosis or leukopenia
Sever sepsis is defined as sepsis plus what?
- Cardiovascular (hypotensive for at least one hour despite volume resuscitation)
- Renal (low urine output for hour despite volume resus)
- Pulmonary
- Hematologic: platelet count below 80 or decreased by 50% in 3 days
- Metabolic: pH < 7.3 and plasma lactate >1.5 x upper normal
Secondary or extravascular BSI is
documented portal of bacterial entry and/or a known associated site of infection (pneumonia in lung, UTI, post-surgical wounds)
