181. Potential Benefit of Masking and other COVID-19 Infection Prevention Measures on Late-Onset Infections in the NICU

Abstract Background Incidence of blood stream infections (BSI) among NICU admissions remains high, with associated mortality and morbidity. Due to COVID-19, there are increased infection prevention (IP) measures in NICUs including universal masking for all healthcare workers and families, social distancing, visitation restrictions, and increased attention to hand hygiene. These measures may also affect late-onset infection rates and offer understanding of novel interventions for prevention. Methods We examined infection rates during the 24 months prior to implementation of COVID-19 IP measures (PRE-period) compared to the months after implementation from April 2020 (POST-period). Late-onset infections were defined as culture-confirmed infection of the blood, urine, or identification of respiratory viral pathogens. An interrupted time series analysis of infection per 1000 patient days was performed based on a change-point Poisson regression with a lagged dependent variable and the number of patient days used as offsets. Each month was treated as independent with additional analysis using an observation-driven model to account for serial dependence. Results Multicenter analysis to date included all infants cared for at three centers (Level 3 and 4) from 2018-2020. Monthly BSI rates decreased in the POST-period at the three centers (Figure 1). At all centers actual BSI rate was lower than the expected rate in the POST-period (Figure 2). The combined BSI rate per 1000 patient days was 41% lower compared to the rate prior to implementation (95% CI, 0.42 to 0.84, P=0.004) (Table 1). In subgroup analysis by birthweight, infants< 1000g had a 39% reduction in BSI (P=0.023), for1000-1500g patients there was a 44% reduction (P=0.292) and in those > 1500g there was a 53% reduction (0.083). Figure 1. PRE and POST MASKING and other COVID Infection Prevention Measures and Monthly BSI Rates. Figure 2. PRE and POST MASKING and other COVID infection prevention measures and BSI Trends. At all centers actual BSI rate was lower than the expected rate for that center in the POST period. UVA and Duke showed a baseline decrease and Pennsylvania Hospital showed a downward trend in infection rates. There was an approximate decrease in expected bloodstream infection events at Pennsylvania Hospital by 7 events, at UVA by 22 events and at Duke by 23 events. Overall, all three centers saw a decrease in their expected infections after COVID-19 infection prevention measures were implemented. Table 1. Percent reduction in Bloodstream Infection at each center. Conclusion In this preliminary analysis, we found a reduction of BSI after the implementation of COVID-19 infection prevention measures. Additionally, there were fewer viral infections, though there were a limited number of episodes. Further analyses of multicenter data and a larger number of patients will elucidate the significance of these findings and the role some of these IP measures such as universal masking may have in infection prevention in the NICU. Disclosures All Authors: No reported disclosures

Genes mapping to the Comprehensive Antibiotic Resistance Database were measured pre-(x-axis) and post-travel (y-axis) to assess the acquisition of resistance genes in association with travel, distinguished by geographic region. Colors indicate geographic regions visited by travelers: South America (red), South East Asia (blue), South Asia (green), Eastern Africa (purple), Southern Africa (orange), Other (grey).
Conclusion. International travel is associated with a perturbation in the gut microbial community, with the acquisition of AMR bacteria and genes, and an increase in the relative abundance of E. coli. These perturbations following travel may be important factors in the global spread of AMR.
Disclosures. Background. Incidence of blood stream infections (BSI) among NICU admissions remains high, with associated mortality and morbidity. Due to COVID-19, there are increased infection prevention (IP) measures in NICUs including universal masking for all healthcare workers and families, social distancing, visitation restrictions, and increased attention to hand hygiene. These measures may also affect late-onset infection rates and offer understanding of novel interventions for prevention.
Methods. We examined infection rates during the 24 months prior to implementation of COVID-19 IP measures (PRE-period) compared to the months after implementation from April 2020 (POST-period). Late-onset infections were defined as culture-confirmed infection of the blood, urine, or identification of respiratory viral pathogens. An interrupted time series analysis of infection per 1000 patient days was performed based on a change-point Poisson regression with a lagged dependent variable and the number of patient days used as offsets. Each month was treated as independent with additional analysis using an observation-driven model to account for serial dependence.
Results. Multicenter analysis to date included all infants cared for at three centers (Level 3 and 4) from 2018-2020. Monthly BSI rates decreased in the POST-period at the three centers (Figure 1). At all centers actual BSI rate was lower than the expected rate in the POST-period (Figure 2). The combined BSI rate per 1000 patient days was 41% lower compared to the rate prior to implementation (95% CI, 0.42 to 0.84, P=0.004) ( Table 1). In subgroup analysis by birthweight, infants< 1000g had a 39% reduction in BSI (P=0.023), for1000-1500g patients there was a 44% reduction (P=0.292) and in those > 1500g there was a 53% reduction (0.083).  At all centers actual BSI rate was lower than the expected rate for that center in the POST period. UVA and Duke showed a baseline decrease and Pennsylvania Hospital showed a downward trend in infection rates. There was an approximate decrease in expected bloodstream infection events at Pennsylvania Hospital by 7 events, at UVA by 22 events and at Duke by 23 events. Overall, all three centers saw a decrease in their expected infections after COVID-19 infection prevention measures were implemented.

Conclusion.
In this preliminary analysis, we found a reduction of BSI after the implementation of COVID-19 infection prevention measures. Additionally, there were fewer viral infections, though there were a limited number of episodes. Further analyses of multicenter data and a larger number of patients will elucidate the significance of these findings and the role some of these IP measures such as universal masking may have in infection prevention in the NICU.
Disclosures. Background. Starting in the late 1940s-1950s Staphylococcus aureus isolates gained resistance to penicillin largely through the acquisition of β-lactamases. In recent years, some centers have described an increase in the proportion of methicillin susceptible S. aureus (MSSA) which are also susceptible to penicillin (PSSA). There are little data on the prevalence or clinical significance of PSSA in children. Acute hematogenous osteoarticular infections (AHOAIs, including osteomyelitis and septic arthritis) are the most common manifestation of invasive S. aureus disease in children. We investigated the prevalence of penicillin susceptibility among MSSA AHOAI isolates at two children's hospitals.
Methods. MSSA AHOAI isolates were obtained through surveillance studies at Texas Children's (TCH) and St. Louis Children's Hospitals (SLCH) from 1/2011-12/2019. All isolates underwent PCR for blaZ β-lactamase, PVL genes and agr group. All blaZ negative isolates then underwent penicillin susceptibility testing using macrobroth dilution. Isolates which were blaZ negative and had a penicillin MIC ≤ 0.125 μg/ ml were regarded as PSSA.
Results. 329 unique isolates were available and included in the study. The median patient age was 9.2 years (IQR: 5.1-12.2). Overall, 22 isolates were found to be penicillin susceptible (6.7%). No PSSA isolates were detected prior to 2015 but increased yearly thereafter; by the final study year 20.4% of isolates were PSSA (p=0.001, Figure  1). Patients with PSSA isolates were slightly older than those with resistant isolates (median age 11.8 years vs. 9.1 years, p=0.08) and PSSA were more commonly identified at SLCH (12.9% vs. 5.2%, p=0.04). PSSA were similar to penicillin-resistant isolates in terms agr group and PVL carriage as well as clinical presentation and outcomes.
The figure describes the relative frequency of penicillin susceptible S. aureus (PSSA) over time among MSSA osteoarticular infection isolates in children.
Distribution of MICs to penicillin, ampicillin, cefazolin, cephalexin and oxacillin among PSSA isolates.
Conclusion. PSSA appears to be increasing among AHOAI isolates in US children, although geographic variability does occur. Overall, PSSA isolates are associated with a similar clinical presentation as penicillin-resistant isolates. Penicillin susceptibility testing may serve as an avenue for future stewardship intervention in staphylococcal infections. Disclosures