Infectivity of SARS-CoV-2 on Inanimate Surfaces: Don't Trust Ct Value.

SARS-CoV-2 RNA is frequently identified in patient rooms and it was speculated that the viral load quantified by PCR might correlate with infectivity of surfaces. To evaluate Ct values for the prediction of infectivity, we investigated contaminated surfaces and Ct-value changes after disinfection. Viral RNA was detected on 37 of 143 investigated surfaces of an ICU. However, virus isolation failed for surfaces with a high viral RNA load. Also, SARS-CoV-2 could not be cultivated from surfaces artificially contaminated with patient specimens. In order to evaluate the significance of Ct values more precisely, we used surrogate enveloped bacteriophage Φ6. A strong reduction in Φ6 was achieved by three different disinfection methods. Despite a strong reduction in viability almost no change in the Ct values was observed for UV-C and alcoholic surface disinfectant. Disinfection using ozone resulted in a lack of Φ6 recovery as well as a detectable shift in Ct values indicating strong degradation of the viral RNA. The observed lack of significant effects on the detectable viral RNA after effective disinfection suggest that quantitative PCR is not suitable for predicting the infectivity of SARS-CoV-2 on inanimate surfaces. Ct values should therefore not be considered as markers for infectivity in this context.

Efficacy of introducing a checklist to reduce central venous line associated bloodstream infections in the ICU caring for adult patients.

BACKGROUND: Central line-associated bloodstream infections (CLABSI) are a major source of sepsis in modern intensive care medicine. Some years ago bundle interventions have been introduced to reduce CLABSI. The use of checklists may be an additional tool to improve the effect of these bundles even in highly specialized institutions. In this study we investigate if the introduction of a checklist reduces the frequency of CLABSI. METHODS: During the study period from October 2011 to September 2012, we investigated the effect of implementing a checklist for the placement of central venous lines (CVL). Patients were allocated either to the checklist group or to the control group, roughly in a 1:2 ratio. The frequency of CLABSI was compared between the two groups. RESULTS: During the study period 4416 CVL were inserted; 1518 in the checklist group and 2898 in the control group. The use of the checklist during CVL placement resulted in a lower CLABSI frequency. The incidence in the checklist group was 3.8 per 1000 catheter days as compared to 5.9 per 1000 catheter days in the control group (IRR = 0.57; p = 0.001). The use of the checklist also reduced the frequency of catheter colonisation significantly, 36.3 per 1000 catheter days in the checklist group vs 21.2 per 1000 catheter days in the control group, respectively (IRR = 0.58; p < 0.001). CONCLUSION: The introduction of a checklist to improve the adherence to hygiene standards while placement of central venous lines reduced the frequency of infections significantly.