This week in lecture we discussed sepsis and septic shock. Sepsis is a systemic inflammatory response syndrome plus a documented infection. Septic shock is sepsis with hypotension despite fluid resuscitation, and evidence of inadequate tissue perfusion. Bacteria can either originate within the cardiovascular system from endocarditis, mycotic aneurism, or from an IV catheter or the bacteria can enter the blood through the lymphatic system from another site of infection such as a urinary or respiratory tract infection. Some common organisms that cause intravascular bacteremia are S. aureus, S. epidermidis, S. pneumoniae, HACEK organisms, and viridians streptococci. Extravascular bacteremia can be caused by E. coli, K. pneumonia, P. aeruginosa, S. aureus, and S. pneumoniae.
If sepsis is a concern the physician will order blood cultures to be taken and examined by the laboratory. A blood culture is blood obtained form 1 venipuncture site regardless of the number of bottles filled. Bottles are held for 5 days unless they are determined positive by the automated system. The BacT/ALERT is an automate system which detects a color change of the pH sensor on the bottom of the bottles. When microorganisms from in the bottle CO2 is released and generates free hydrogen ions causing a decrease in pH. The pH change results in the sensor color changing from green to yellow.
Technologists must be aware of common contaminants that can be found in blood cultures. S. epidermidis, Corynebacterium sp, Micrococcus, Viridans strep, and Bacillus sp are a few examples of contaminants. I would like to know more about how technologists confirm it is a contaminant and if there is any additional testing that should be done.
I’ve also posted an article is that I found interesting that was written after Jim Henson died of septic shock from S. pneumoniae. It mentions how time sensitive these infections can be and without immediate treatment the infection can be fatal. (Click on the title of this post for the link)
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