388. Multidrug Resistant Gram Negative Organisms Prevalence in Hospitalized Patients in an Italian Tertiary Level Hospital During COVID-19 Pandemia: First Detection is More Frequent in Clinical Samples than in Surveillance Rectal Swabs with Respect to the Previous 14-Month Period

Background: In Italy the pandemic of COVID-19 infection has placed an enormous burden on health authorities: contact precautions are required to avoid viral transmission and people should be subjected to standard infection control procedures This is crucial in a country experiencing a high number of confirmed cases of COVID-19 infection in Europe and where multidrug-resistant Gram-negative bacteria (MDR-GN) are endemic The aim of this study was to compare the prevalence of MDR-GN in surveillance rectal swabs (SRS) and in clinical samples (CS) in the period March 1,2020- April, 24 2020 with respect to the previous 2-month period and to the previous year Methods: The first SRS and the first CS with a MDR-GN isolate detected from 01/01/2019 to 24/04/2020 were included Analysis was made by comparing three different study periods in 2019 and 2020 (Jan-Dec 2019, Jan-Feb 2020, and Mar-Apr 2020), for medical department, surgical department and intensive care department Results: Overall, 612 MDR-GN organisms were identified (399 SRS and 213 CS): carbapenemase-producing Klebsiella pneumoniae and Acinetobacter baumanii (CPAB) were the most frequently detected (Figure 1) We observed an increased relative frequency of patients with MDR-GN detected in CS respect to those found in SRS (32 7% vs 44 5% vs 70 6%, p=0 0005): 5/12 CS detected in the last period were isolated from the respiratory tract (Figure 2) Nine patients with COVID-19 pneumonia had MDR-GN All but two patients had a previous negative SRS performed 4 days before (median value) and the median interval between COVID-19 positivity and MDR-GN positivity was 7 days The six patients with CPAB isolation were all hospitalized in the same ward, with partially overlapping hospital stays during the study period In 5 of them, CPAB was detected in the respiratory tract (Figure 3) Conclusion: The first detection of MDR-GN in CS and the nosocomial MDR-GN acquisition despite cohorting due to COVID-19 infection underline the need to reinforce infection control measures in a high prevalence country during COVID-19 pandemia A correct antimicrobial policy urged because, according to published data, most patients with COVID-19 infection received antimicrobial therapy: furthermore MDR-GN infection could play a role in the negative outcome of these patients