2016 NHSN – Secondary Bloodstream Infections

2016 NHSN – Secondary Bloodstream Infections


Welcome to the 2016 National Healthcare Safety Network Quick Learn series. These CDC presentations are an educational resource for healthcare facilities working to prevent Healthcare Associated Infections, or H-A-Is. In this series, we’ll review secondary bloodstream infections. NHSN frequently receives questions about the correct application of the Repeat Infection Timeframe, or RIT, concept as it relates to secondary bloodstream infections. We are often asked, “If a bloodstream infection, or BSI, is determined to be secondary to a primary site of infection, does this create a BSI RIT that will account for all subsequent positive blood cultures from this patient for the next 13 days?” The answer is no. The Repeat Infection Timeframe and Secondary Bloodstream Infection attribution period are two distinct periods. Let’s review. For purposes of NHSN surveillance, a bloodstream infection if the organism identified from the blood is related to an NHSN-defined primary site-specific infection. For a bloodstream infection to be identified as secondary BSI, all of the following must be true. First, the patient must meet one of the NHSN site-specific infection criteria. Second, the blood culture collection date must occur in the site-specific infection’s Secondary BSI Attribution Period. And third, one of the scenarios outlined in the Secondary BSI Guide found in Appendix 1 of the BSI protocol, must be satisfied. That is: EITHER an organism identified from the site specific infection that is used as an element to meet the site-specific infection criterion must have at least one matching organism found in the blood specimen OR the positive blood specimen must be used as an element to meet the site-specific infection criterion. Let’s look at examples of each of the two scenarios. In the first scenario, the organism identified from an infection site must be used as an element to meet the site-specific infection criterion AND the blood specimen must contain at least one matching organism to the site specimen. In this example, E.coli is found in the urine. The symptomatic urinary tract infection, or SUTI-1, infection criterion is met. Within the SUTI secondary BSI attribution period, the same organism found in the urine culture is also found in the blood culture. Therefore, the BSI is secondary to the SUTI. In the second scenario, the positive blood specimen must be used as an element to meet the site-specific infection criterion. In this example we have a non-surgical intra-abdominal, or IAB infection. This patient meets IAB criterion 3b, which requires 2 signs or symptoms, in this case, the nausea and abdominal pain, an imaging test evidence of infection AND identification of an organism in a blood specimen. Because the pathogen in the blood specimen is used to meet the IAB infection criterion, the BSI is secondary to the IAB infection. Note the blood culture collection date on 2/16 occurs within the IAB infection window period and likewise in the IAB secondary BSI attribution period. These examples are the only two ways that a BSI may be considered secondary. Now, given those two examples, let’s review the concept of the repeat infection timeframe, or RIT. The RIT is a 14-day timeframe during which no new infections of the same type are reported. The date of event is Day 1 of the 14-day RIT. Additional pathogens identified during the RIT from the same type of infection are simply added to the event. A new event is not reported. Now, let’s review the concept of the secondary bloodstream infection, or BSI, attribution period. The secondary BSI attribution period is the period in which a positive blood specimen must be collected to be considered as a secondary bloodstream infection to a primary site infection. This period includes the Infection Window Period plus the RIT. It is 14-17 days in length, depending upon the date of event. It’s important to point out the RIT and the secondary BSI attribution period are both associated with the site-specific infection. In this example, the site specific infection is the SUTI. Any additional qualifying urine culture pathogens identified within that SUTI RIT are added to the originally reported event. No new UTI infections are reported during the repeat infection timeframe. In this example, the pathogen, Staphylococcus aureus, is added to the originally reported SUTI event. Continuing with the same example, note the secondary BSI Attribution period for the SUTI does NOT apply to all subsequent bloodstream infections. The Secondary BSI attribution period is associated with the SUTI only. The blood culture with a collection date during the secondary BSI attribution period of the SUTI that does not have a matching organism to the site specific culture of urine cannot be attributed as secondary to the SUTI event. The secondary BSI attribution period does not automatically account for all positive blood cultures that occur during that period. The blood culture collected on 2/20 that is growing Klebsiella pneumoniae does not have a matching organism to the urine culture Therefore, it cannot be attributed as a secondary BSI to the SUTI. This BSI must be evaluated to determine if it’s secondary to another site of infection or if it’s a primary BSI. It could possibly be a central line-associated bloodstream infection, or CLABSI. Do not confuse a primary BSI Repeat Infection Timeframe with a secondary BSI attribution period. In this example, the infection criterion for a laboratory confirmed bloodstream infection, LCBI is met. A primary bloodstream infection is identified. Just like all other identified site-specific infections, identification of a primary BSI produces a 14 day repeat infection timeframe, or RIT, in this case a BSI RIT. Note that a primary BSI never has a secondary BSI attribution period. No new primary BSIs will be reported during this BSI-RIT. In this case the organisms do not have to match. The BSI is a primary site of infection and any additional organisms recovered during the RIT of the same type of infection, a BSI in this case, are added to the originally reported event. Returning to our original question… If a BSI is determined to be secondary to another primary site of infection, does this create a BSI RIT, which means I can exclude all positive blood cultures from the same patient from BSI surveillance during the next 13 days? The answer is NO. A secondary BSI does not create a BSI RIT for all subsequent positive blood cultures. The concepts covered in this quick learn apply to HAI and POA determinations. Based on that determination, the assignment of pathogens recovered from subsequent blood cultures are assigned accordingly. This concludes the NHSN Quick Learn focusing on BSIs and RITs. For additional questions, please contact NHSN user support at [email protected]

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