CATETER RELATED BLOODSTREAM INFECTIONS-diagnosis

LCBI (Laboratory confirmed Bloodstream infection) must have at least one of the following conditions;

• The patient must have a pathogen defined in at least 1 blood culture and this pathogen should not be responsible for infection on the other side of the body.
• The patient must have at least one of the following symptoms; Tremor or hypotension; And the pathogen should not be associated with infection in another area, or if the pathogen is a common commensal, it should be shown at least ≥ 2 blood cultures and cultures should be obtained from different parts of the body.

MBI-LCBI denilen bir kavram da, LCBI’nin bir alt grubu olarak ortaya atılmıştır

(MBI: Mukozal bariyer injuri).

This concept is the presence of enteric organisms in at least one blood culture from patients with neutropenia or diarrhea, who are advanced haemopoietic stem cell transplant patients with advanced Graft Versus Host disease.

Although the most sensitive finding in catheter-related bloodstream infection (CRBI) is fever, the specificity is low.

Inflammation and purulence in the catheter entry site have better specificity, but lower sensitivity.

Other clinical findings; Hemodynamic instability, altered mental status, catheter dysfunction, septicemia findings starting with catheter infusion.

Complications due to bloodstream infections can also be seen; Suppurative thrombophlebitis, endocarditis, osteomyelitis, metastatic infection etc.

Conditions where no other source of infection is present, if the S. aureus, coagulase (-) Staphylococci and Candida species are obtained in blood cultures, the CRBI is mentioned.

Cultures from peripheral venules have lower false positives than cultures from the catheter. In blood cultures from both routes, the (-) predictive value is very good.

If there is no possibility of obtaining peripheral vascular blood culture; It is necessary to take ≥ 2 blood cultures from 2 separate lumens of the multi-lumen catheter.

Diagnostic criteria for CRBI;

The production of the same microorganism from two catheter tips and at least 1 peripheral venous culture,

Production of the same microorganism from at least 2 blood cultures (one from the central lumen of the catheter, the other from the peripheral vein or the second lumen of the catheter). This should meet the criteria of quantitative blood cultures or the criteria of Differential time to Positivity.

If the quantitative culture from the catheter hub shows a colony count of ≥ 3 folds compared to the cultures provided from the peripheral veins or the cultures obtained from the second lumen, CRBI is considered to be in favor.

In semi- quantitative culture; If both the catheter entry site, the catheter nipple and the peripheral culture produce> 15 cfu of the same microorganism, this is in favor of CRBI.

Diferential time to positivity; If the cultures taken from the catheter start> 120 minutes before the culture from the peripheral veins, CRBI can be shown with 85% sensitivity and 91% specificity.

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