bluuebunny/crossref_metadata_2025 huggingface dataset:
Change to hospitalist providers had a minimal influence on overall antibiotic use in a VA long-term care setting
Authors: Bej Taissa , Wilson Brigid , Perez Federico , Jump Robin
Published: September 2023

Background: In long-term care settings, practice patterns among practitioners are stronger determinants of antibiotic use than resident characteristics. In July 2021, hospitalists from the acute medicine service replaced geriatricians and assumed the care of residents in a 110-bed community living center (CLC) at a large academic Veterans Affairs (VA) medical center. We assessed changes in antibiotic use associated with that change of practitioners to guide stewardship efforts. We hypothesized that antibiotic use in the CLC would shift, reflecting the practice pattern of practitioners accustomed to treating patients in acute-care settings. Methods: We conducted a retrospective cohort study from July 1, 2020, through June 30, 2022, 1 year before and after the change of practitioners on July 1, 2021. We assessed resident characteristics and the following metrics of antibiotic use at monthly intervals: days of therapy (DOT) per 1,000 bed days of care (BDOC), antibiotic starts per 1,000 BDOC, and mean length of therapy (LOT) in days. We also compared the DOT per 1,000 BDOC for various antibiotics, in groups and individually. Results: In the years before and after the change of practitioners on July 1, 2021, the characteristics of CLC residents were comparable. Before and after July 1, 2021, monthly DOT per 1,000 BDOC (Fig. 1A), antibiotic starts per 1,000 BDOC, and mean LOT (Fig. 1B) were similar. After July 1, 2021, the use of fluoroquinolones decreased (14.31 vs 5.83 DOT per 1,000 BDOC; P < .01), and variations in anti-MRSA, narrow-spectrum, and broad-spectrum hospital agents were small, whereas the use of broad-spectrum community agents increased (29.42 vs 47.81 DOT per 1,000 BDOC; P < .01) (Fig. 2A). Within this group, there was increased use of doxycycline (7.42 vs 19.13 DOT per 1,000 BDOC; P < .01), ertapenem (2.03 vs 4.58 DOT per 1,000 BDOC; P < .01), and, modestly, azithromycin (0.40 vs 1.80 DOT per 1,000 BDOC) (Fig. 2B). Conclusions: The overall use of antibiotics, as measured by DOT, antibiotic starts, and LOT did not change after hospitalists assumed care of CLC residents. However, a notable decrease was observed in the use of fluoroquinolones, and an increase was observed in the use of doxycycline and ertapenem. Stewardship that is tailored to the type of provider and incorporates their practice patterns is needed to reinforce the prudent use of antibiotics.

Disclosures: None
Whole-genome sequencing of carbapenem-resistant Enterobacterales isolates and evaluation of hospital-acquired infections
Authors: Ajaka Leama , Day Shandra , Liscynesky Christina , Colburn Nora , Sun Christine , Sovic Michael , Pancholi Preeti , Balada-Llasat Joan-Miquel , Smith Heather , Murthy Shashanka
Published: September 2023

Background: Multidrug-resistant organisms (MDROs) are increasingly implicated in nosocomial outbreaks worldwide. We evaluated whole-genome sequencing (WGS) as an adjunctive epidemiological tool to identify infection clusters and MDRO transmission in the healthcare setting. Methods: Clinical isolates of carbapenem-resistant Enterobacterales (CRE) from July 1, 2021, to June 30, 2022, underwent Illumina WGS. Assembled genomes were taxonomically classified with GTDB-Tk software and were typed using multilocus sequence typing (MLST). Average nucleotide identity (ANI) was calculated between genomes. Numbers of differences among core single-nucleotide polymorphisms (SNPs) were calculated for pairs within taxonomic groups, and the data were evaluated in the context of patient dates and locations of care obtained from the electronic medical record. Results: In total, 39 CRE isolates underwent WGS (Fig. 1). Klebsiella pneumoniae represented the largest number of isolates (n = 18). Using MLST, 2 distinct groups of K. pneumoniae were identified (ST307 and ST258) with 5 and 4 isolates, respectively (Fig. 2). Within ST307, SNP differences ranged between 8 and 115. 3 isolates (CRE8, CRE10, and CRE12) were collected within 4 weeks of each other and had ≤26 pairwise SNP differences. Notably, CRE8 and CRE10 were located on the same unit at the same time and used the same MRI scanner on the same day. CRE35 had >95 SNP differences and was admitted 8 months prior to others in ST307 but had surgery in the same OR as CRE8. Within ST258, pairwise comparison of samples revealed 139–588 SNP differences. CRE21, CRE31, and CRE33 had SNP differences of ≤150. These patients were in the same hospital room (CRE33 and CRE21) and unit (CRE31 and CRE33), but they did not overlap temporally. CRE37 had >580 SNP differences, with no overlap in hospitalization dates or locations with other patients. Conclusions: Two closely related K. pneumoniae isolate populations were identified using WGS. Strong temporal and spatial commonalities were identified among isolates with few SNP differences. Isolate pairs with intermediate SNP differences shared spatial commonalities, suggesting possible indirect transmission between patients. No common exposures were identified for pairs with large numbers of SNP differences. WGS is an evolving tool to detect outbreak clonal populations of MDRO not identified through traditional epidemiologic techniques. WGS can provide insight into transmission patterns and the role of environmental contamination in propagating these nosocomial infections. More studies are needed to define the role and clinical significance of isolates with intermediate SNP differences in transmission of these pathogens between hosts and the healthcare environment.

Disclosures: None
Identifying patients at high risk for carbapenem-resistant Enterobacterales carriage upon admission to acute-care hospitals
Authors: Howard-Anderson Jessica , Asrani Radhika Prakash , Bower Chris , Robichaux Chad , Kamaleswaran Rishi , Jacob Jesse , Fridkin Scott
Published: September 2023

Background: Prompt identification of patients colonized or infected with carbapenem-resistant Enterobacterales (CRE) upon admission can help ensure rapid initiation of infection prevention measures and may reduce intrafacility transmission of CRE. The Chicago CDC Prevention Epicenters Program previously created a CRE prediction model using state-wide public health data (doi: 10.1093/ofid/ofz483). We evaluated how well a similar model performed using data from a single academic healthcare system in Atlanta, Georgia, and we sought to determine whether including additional variables improved performance. Methods: We performed a case–control study using electronic medical record data. We defined cases as adult encounters to acute-care hospitals in a 4-hospital academic healthcare system from January 1, 2014, to December 31, 2021, with CRE identified from a clinical culture within the first 3 hospital days. Only the first qualifying encounter per patient was included. We frequency matched cases to control admissions (no CRE identified) from the same hospital and year. Using multivariable logistic regression, we compared 2 models. The “public health model” included 4 variables from the Chicago Epicenters model (age, number of hospitalizations in the prior 365 days, mean length of stay in hospitalizations in the prior 365 days, and hospital admission with an infection diagnosis in the prior 365 days). The “healthcare system model” added 4 additional variables (admission to the ICU in the prior 365 days, malignancy diagnosis, Elixhauser score and inpatient antibiotic days of therapy in the prior 365 days) to the public health model. We used billing codes to determine Elixhauser score, malignancy status, and recent infection diagnoses. We compared model performance using the area under the receiver operating curve (AUC). Results: We identified 105 cases and 441,460 controls (Table 1). CRE was most frequently identified in urine cultures (46%). All 4 variables included in the public health model and the 4 additional variables in the healthcare system model were all significantly associated with being a case in unadjusted analyses (Table 1). The AUC for the public health model was 0.76, and the AUC for the healthcare system model was 0.79 (Table 2; Fig. 1). In both models, a prior admission with an infection diagnosis was the most significant risk factor. Conclusions: A modified CRE prediction model developed using public health data and focused on prior healthcare exposures performed reasonably well when applied to a different academic healthcare system. The addition of variables accessible in large healthcare networks did not meaningfully improve model discrimination.

Disclosures: None
Environmental factors associated with invasive mold infections at a tertiary-care hospital
Authors: Tully Lindsey , Gaillard Schuyler L. , Zheng Lucy , Millson Tara , Kumar Princy , Timpone Joseph
Published: September 2023

Background: Invasive mold infections (IMIs) in hospitalized patients can result in significant morbidity and mortality. Environmental factors, such as hospital construction and negative air-pressure rooms (NAPRs), have been associated with hospital-acquired IMI. Increased utilization of NAPRs during the COVID-19 pandemic created a unique opportunity to examine the impact of NAPRs on IMI risk. Methods: From 2018 to present, a new pavilion was being constructed adjacent to our hospital. The Theradoc platform was used to identify positive mold cultures among adult patients hospitalized at our institution between March 1, 2017, and October 15, 2022. We performed a retrospective chart review of 262 mold isolates to determine patient demographics, timing of IMI, and their relationship to hospital construction and exposure to NAPR. IMI incidence was compared across 3 observation periods: (A) before hospital construction; (B) during hospital construction alone; and (C) during hospital construction and NAPR enhancement during the COVID-19 surge. Hospital-acquired IMI was defined as an infection that occurred >72 hours after admission. A REDCap database was created for data storage and R software was used for data analysis. Results: Of the 262 mold isolates identified, 61 cases were classified as IMI, of which 29 were hospital-acquired IMI. The mean age of IMI patients was 51.8 years, and 55.2% were male. Among them, 20.7% were exposed to NAPR during admission; 65.5.% were immunocompromised; and 2 patients were diagnosed with COVID-19. The all-cause mortality rate among hospital-acquired IMI cases was 79.3% (23 of 29). Also, 82.8% of hospital-acquired IMI cases were respiratory in nature, with 83.3% of these cases due to Aspergillus spp. Yearly rates of hospital-acquired IMI were 3.0 before construction versus 5.6 during construction (periods B and C). Yearly rates of hospital-acquired IMI, respiratory IMI, and invasive pulmonary aspergillosis by period were as follows: Period A had 3 hospital-acquired IMI cases per year, 2 hospital-acquired respiratory IMI cases per year, and 3 hospital-acquired invasive pulmonary aspergillosis cases per year. Period B had 4.5 hospital-acquired IMI cases per year, 3.5 hospital-acquired respiratory IMI cases per year, and 3.0 hospital-acquired invasive pulmonary aspergillosis cases per year. Period C had 6.5 hospital-acquired IMI cases per year, 5.4 hospital-acquired respiratory IMI cases per year, and 5.0 hospital-acquired invasive pulmonary aspergillosis cases per year. Conclusions: Hospital-acquired IMI was associated with a high mortality. Our data demonstrate a >2-fold increase in yearly incidence of hospital-acquired IMI before construction compared with during construction in association with increased implementation of NAPR. We have now reversed the trend in NAPR at our hospital’s designated COVID-19 units.

Disclosures: None
Importance of carbapenem-resistant Enterobacteriaceae screening to prevent transmission within an acute-care hospital
Authors: Hudziec Meghan , Totten Sarah , Pisney Larissa , Faliano Cara
Published: September 2023

Background: Carbapenem-resistant Enterobacteriaceae (CRE) present a serious public health risk because they are transmissible within the acute-care hospital setting, and they are associated with significant morbidity and mortality. Timely identification of CRE among hospitalized patients is essential to ensure that appropriate infection prevention measures are enforced to prevent transmission events. In 2022, 9 index CRE cases (5 Klebsiella pneumoniae carbapenemase (KPC)–producing and 4 New Delhi Metallo-β-lactamase (NDM)–producing cases) were identified within the University of Colorado Hospital (UCH) inpatient population. In response to index case identification, tracing was performed to identify patients with an epidemiologic link for targeted CRE screening to detect asymptomatic CRE carriage. Methods: In total, 645 patients were screened allowing for timely identification of CRE colonization within 6 patients (3-KPC; 1-OXA-48; 1-NDM; 1-KPC/OXA-48). Secondary case identification elicited additional evaluation of service team and mobile-device crossover between positive patients, as well as primary and ancillary treatment locations. Results: Investigations revealed 3 possible transmission events in 0.47% of the total screened population. Identification of secondary CRE cases prompted additional testing of exposed patients performed at 7-day intervals to capture a 21-day colonization period. In total, 95 additional patients were screened for CRE during secondary and tertiary CRE screening events. Discussion: Nursing staff collaboration and engagement were critical to achieving a high rate of compliance with CRE screening activities, not only collecting screening specimens but also providing explanation and reassurance to patients. Due to this partnership and diligence, UCH was able to achieve 77% compliance with initial CRE screening events. Secondary and tertiary CRE screening revealed testing compliance of 83% and 69%, respectively. To further reduce the risk of CRE transmission within hospitalized patients, UCH has implemented an enhanced cleaning process for high-risk patient rooms, which includes patients infected or asymptomatically colonized with CRE. This enhanced process is prompted based on CRE or infection status as documented in the electronic medical record (EMR), and it initiates a mandatory 2-phase cleaning process. Future plans include environmental testing audits to validate room decontamination and leveraging the EMR to capture pertinent healthcare and travel histories. Active engagement with public health partners will be pursued to enable molecular testing of high-risk touch points. Conclusions: Patient screening, enhanced decontamination, and monitoring activities are key elements to effectively prevent the spread of CRE within vulnerable patient populations and must be continuously evaluated for improvement opportunities.

Disclosures: None
Multidrug-resistant Acinetobacter outbreak in spinal cord unit identified and stemmed through infection prevention epidemiologic efforts
Authors: O’Neil Sean , Ford Delvina , Beck Erica , Carroll Theresa
Published: September 2023

Background: Drug-resistant pathogens are a significant source of increased cost and patient complications in long-term and/or congregate care settings. Once introduced, depending on the environmental niche in which they establish and the mechanisms they employ for survival, they can be difficult to eradicate. We report the details of an epidemiologic investigation of a multidrug-resistant Acinetobacter baumannii (MDR-A) outbreak in a spinal cord intervention (SCI) unit within a Veterans Affairs facility in San Antonio, Texas, that was identified after back tracing a positive wound culture from a long-term resident. Methods: All MDR-A isolates were matched to the patients harboring them. Their clinical, epidemiologic, and geographic histories within our facility were traced. All potentially shared characteristics between cases were evaluated closely. Results: In total, 5 cases were determined to be likely connected over a period of ~18 months starting December 2020. The extant isolates underwent molecular evaluation and were genetically related. Patient activity was traced by the infection prevention team to identify potential sources of transmission. Environmental sampling after standard cleaning found a common strain on a shower trolley shared by these patients. Following focused cleaning of this and other shared locations, no new related isolates have been identified from patient or environmental samples. Conclusions: In this case, investigation by the infection prevention team of a single multidrug-resistant organism led to identification and eradication of a potential pathogen. Despite standard cleaning processes, a likely shared fomite was identified and decontaminated, thereby preventing future infections. This case exemplifies the value of thorough epidemiologic study paired with modern molecular methods of identification.

Disclosures: None
Electrifying the case review process for better speed, reach, and impact
Authors: Gutowski Jennifer , Bronstein Melissa , Tatro Adam , Frey Stephany , Lesho Emil
Published: September 2023

Background: Prevention of healthcare-associated infections (HAIs) requires timely feedback to and input from all staff involved in patient care to best identify practice gaps and improvement targets. However, multidisciplinary review of HAI events can be challenging to promptly complete given staffing shortages and the excess administrative burden of emailed and printed forms and disjointed analyses, reporting, and visualization tools. Plagued by a lack of feedback from attending and ordering physicians, difficulty transcribing and analyzing nonstandardized data, and challenges in summarizing and distributing actionable findings, we sought to reduce turnaround time (TAT), improve data collection, and broaden communication of HAI contributing factors and proposed solutions. Methods: A secure web application for electronic data capture and reporting, Research Electronic Data Capture (REDCap), was used; the software application is free to nonprofit organizations. The review process is now initiated by an infection preventionist entering HAI information into an initial survey, which automatically cascades information into 4 subsequent surveys, distributed through automated email links, providing an opportunity for individual responses from the nursing unit, the attending provider, an infectious disease physician, and the ordering provider for the positive test that detected the HAI. Survey questions focus on evaluation of adherence to CDC and SHEA HAI prevention strategies. Reminders are automatically generated and continue to be sent to involved staff until their portion is completed. Survey responses are automatically summarized upon completion of all reviews and are shared with several stakeholders, including hospital leadership, the care team, infection prevention staff, and quality-control partners (Fig.). Discrete qualitative and quantitative data are exported in a standard application-programming interface (API) format for immediate analysis and interpretation. Results: After the review process was launched using new electronic technology, the average TAT and completion rate improved from 23 days and 40% to 7 days and 95%, respectively. Input from ordering and attending physicians, once extremely rare, became frequent. Nuanced insight into causative and preventive factors, previously unachievable, occurred during review of all 38 HAIs reported in December 2022. Reviewers believed that 48% of HAIs reviewed could have been prevented. Conclusions: Applying electronic technology to HAI case review improved completion and timeliness of reviews by both providers and nurses. By sharing data and insights with all stakeholders in real time, the new procedure permitted multidirectional communication between the care teams and increased awareness of patient harm as well as ownership of patient safety. Our process is freely and readily generalizable to any nonprofit healthcare facility.

Disclosures: None
Susceptibility results discrepancy analysis between NHSN antimicrobial resistance (AR) Option and NEDSS Base System in Tennessee, July 2020–December 2021
Authors: Davis Carol , Ouedraogo Youssoufou , Evans Christopher , Wilson Christopher
Published: September 2023

Background: The NHSN Antimicrobial Resistance (AR) Option is an important avenue for acute-care hospitals to electronically report facilitywide antibiogram data. The NEDSS Base System (NBS) is the statewide surveillance system for mandatory reporting of all carbapenem-resistant Enterobacteriaceae (CRE) cases. The state health department (SHD) validated CRE case data reported through the AR Option to assess completeness and accuracy. Methods: NHSN AR Option data from July 2020–December 2021 for 24 facilities were validated by comparing reported CRE and susceptibility results to CRE isolates reported via the NBS. Isolates were matched based on specimen date, sex, birth month and day, pathogen, and specimen source. NHSN susceptibility results were dichotomized as “not resistant” and “resistant” to match the NBS results. Susceptibility discordance (differing proportions of resistant isolates) of matched pairs were evaluated using the McNemar exact test in SAS version 9.4 software. Results: The SHD identified 270 CRE cases from the NHSN and 1,254 unique CRE isolates from the NBS. Of the NHSN events, 72 (26.67%) were matched to the NBS. Among matched isolates, discordance was significant for doripenem (0 resistant isolates in the NHSN vs 13 in the NBS; P < .001) and imipenem (5 resistant isolates in the NHSN vs 23 in the NBS; P < .0001). Discordance was not significant for ertapenem nor meropenem. Sensitivity analyses maximized the match rate at 30.74% (83 matches) when NBS isolates from unknown sources were included and matching factors were specimen date and date of birth ± 1 day, and pathogen. Among all 6,325 CRE isolates in NBS, 290 (4.58%) did not have a specimen source provided. Of all 47,348 NHSN events, 7,624 (16.10%) had impossible patient birthdays. Conclusions: Many NHSN isolates could not be matched to NBS due to either isolates being missing from NBS or to data differences across the systems. This mismatch highlights the need for data validation and standardization at the point of entry for both systems. Discordant susceptibility outcomes raise concerns about using the NHSN as a method for facility and regional antibiogram data.

Disclosures: None
Increasing rates of ventilator-associated events: Blame it on COVID-19?
Authors: Dash Aditee , Cooper Kaila , Rittmann Barry , Stevens Michael , Bearman Gonzalo , Munoz-Price L. Silvia , Doll Michelle
Published: September 2023

Background: Rates of ventilator-associated events (VAEs), including infection-related ventilator-associated complications (IVACs) and probable ventilator-associated pneumonia (PVAPs) have increased nationwide since the onset of the COVID-19 pandemic. In December 2021, our health system adopted a new electronic medical record (EMR), which changed the way surveillance for VAEs is performed. We reviewed surveillance criteria, COVID-19 status, and culturing practices in attempts to understand why VAE rates continue to be elevated. Methods: We collected data on VAE type, culture data, COVID-19 status, and surveillance criteria for all patients meeting NHSN definitions for VAE from 2018 through November 2022. For all patients in 2022 (post-EMR transition), 2 physicians (A.D. and M.D.) manually reviewed documented ventilator settings from flow sheets to validate the automated EMR data, and they evaluated culture data for appropriateness. Cultures were defined as appropriate unless they were included in “pancultures” for leukocytosis without concern for pneumonia documented. Rates were compared using an interrupted time series (ITS) analysis before and after the onset of the COVID-19 pandemic and the EMR transition. Patient level data were compared across periods using the χ2 test. All analyses were performed using SAS version 9.4 software. Results: COVID-19 has been implicated in the increasing number of VAEs since the pandemic began: 6% of patients in 2020, 18% in 2021, and 23% in 2022 (P < .001). The percentage of patients meeting criteria for VAE by positive end-expiratory pressure (PEEP) decreased from 2018 to 2022 (92%, 95%, 93%, 85%, 85%, respectively; P = .0004). Patients meeting criteria for VAE by fraction of inspired oxygen (FiO2) increased from 2018 to 2022 (9%, 6%, 11%, 17%, 19%, respectively; P = .0002). Manual review of 2022 data indicated opportunities for test stewardship in 8 of 65 patients with cultures (12%). ITS analysis revealed that IVAC+ rates were climbing prior to the onset of the COVID-19 pandemic (Fig. 1). We observed a marked increase in rates with the implementation of our new EMR and the changes to our surveillance process (0.32 cases per 100 ventilator days). Manual review of records from 2022 revealed 5 patients in which documentation of ventilator settings to meet VAE diagnosis could not be retrieved from flow sheets. Conclusions: COVID-19 continues to affect VAE despite vaccine availability and may partially account for elevated rates nationwide. However, changes in EMR-automated VAE surveillance may also affect rates. Our findings suggest that automated surveillance captures transient or spurious changes in ventilator machine settings that do not accurately represent clinical status. These data may contribute to spurious increases in VAE. More studies are needed to better understand the impact of both COVID-19 and automated surveillance on VAE.

Disclosures: None
Using telehealth to support antimicrobial stewardship at four rural VA medical centers: Interim analysis
Authors: Nguyen Alexandria , Alabdely Mayyadah , Bej Taissa , Ewers Tola , Vivo Tammy Walkner Amanda , Crnich Christopher , Livorsi Daniel , Sabzwari Rabeeya , Wilson Geneva , Wilson Brigid , Kowal Corinne , Hicks Oteshia , Evans Charlesnika , Jump Robin
Published: September 2023

Background: Healthcare settings without access to infectious diseases experts may struggle to implement effective antibiotic stewardship programs. We previously described a successful pilot project using the Veterans Affairs (VA) telehealth system to form a Videoconference Antimicrobial Stewardship Team (VAST) that connected multidisciplinary teams from rural VA medical centers (VAMCs) with infectious diseases experts at geographically distant locations. VASTs discussed patients from the rural VAMC, with the overarching goal of supporting antibiotic stewardship. This project is currently ongoing. Here, we describe preliminary outcomes describing the cases discussed, recommendations made, and acceptance of those recommendations among 4 VASTs. Methods: Cases discussed at any of the 4 participating intervention sites were independently reviewed by study staff, noting the infectious disease diagnoses, recommendations made by infectious diseases experts and, when applicable, acceptance of those recommendations at the rural VAMC within 1 week. Discrepancies between independent reviewers were discussed and, when consensus could not be reached, discrepancies were discussed with an infectious diseases clinician. Results: The VASTs serving 4 different rural VAMCs discussed 96 cases involving 92 patients. Overall, infection of the respiratory tract was the most common syndrome discussed by VASTs (Fig. 1). The most common specific diagnoses among discussed cases were cellulitis (n = 11), acute cystitis (n = 11), wounds (n = 11), and osteomyelitis (n = 10). Of 172 recommendations, 41 (24%) related to diagnostic imaging or laboratory results and 38 (22%) were to change the antibiotic agent, dose, or duration (Fig. 2). Of the 151 recommendations that could be assessed via chart review, 122 (81%) were accepted within 1 week. Conclusions: These findings indicate successful implementation of telehealth to connect clinicians at rural VAMCs with an offsite infectious diseases expert. The cases represented an array of common infectious syndromes. The most frequent recommendations pertained to getting additional diagnostic information and to adjusting, but not stopping, antibiotic therapy. These results suggest that many of the cases discussed warrant antibiotics and that VASTs may use the results of diagnostic studies to tailor that therapy. The high rate of acceptance suggests that the VASTs are affecting patient care. Future work will describe VAST implementation at 4 additional VAMCs, and we will assess whether using telehealth to disseminate infectious diseases expertise to rural VAMCs supports changes in antibiotic use that align with principles of antimicrobial stewardship.

Disclosures: None
Comparison of clinical antibiotic susceptibility testing interpretations to CLSI standard interpretations
Authors: Hitchingham Erin , Gambrell Ashley , Villegas Raquel , Muleta Daniel
Published: September 2023

Background: Clinical antibiotic susceptibility testing (AST) interpretations based on minimum inhibitory concentrations (MIC) breakpoints are important for both clinical decision making and some reportable condition criteria. Standardization of MIC breakpoints across clinical laboratories is lacking; AST instruments are often validated for outdated Clinical and Laboratory Standards Institute (CLSI) MIC breakpoint guidelines. In this study, we analyzed the agreement between the reported clinical laboratory AST interpretations and the guideline CLSI interpretation. Methods: Clinical laboratory AST data collected from the Multisite Gram-Negative Surveillance Initiative (MuGSI) carbapenem-resistant Enterobacterales (CRE) surveillance program in Tennessee between 2019 and 2021 were utilized. MIC values from the clinical instrument were used to calculate CLSI standard interpretations following the 2019–2021 CLSI M100 guidelines. Agreement between the clinical laboratory and CLSI interpretations of the reported MIC values were measured using a weighted Cohen κ calculated in SAS version 9.4 software. Total matches were isolates with identical CLSI and clinical laboratory interpretations. Results: In total, 14 antibiotics were assessed. Of those, 9 antibiotics had at least moderate agreement (κ > 0.41) between interpretations. Agreement between the clinical laboratory and the CLSI interpretations were near perfect (κ > 0.81) for 3 antibiotics. Agreement between the clinical laboratory and the CLSI interpretations were poor for cefazolin (0.06) and ertapenem (0.14). Cefotaxime (−0.07) was the only antibiotic that suggested no agreement. Conclusions: Of the antibiotics included in the analysis, 36% had less than moderate agreement between clinical laboratory and CLSI AST interpretations. Given the increases in antimicrobial resistance globally and the emphasis placed on antibiotic stewardship, standardization across clinical AST panels should be prioritized. Inconsistencies have the potential to contribute to inappropriate antibiotic use in addition to under- or overidentification of reportable conditions, including CRE.

Disclosures: None
Paradoxical consequences of wastewater interventions targeting carbapenemase-producing Enterobacterales
Authors: Lehman David , Kotay Shireen , Parikh Hardik , Park Stacy , Mathers Amy
Published: September 2023

Background:Serratia marcescens is a leading cause of hospital-acquired infections. There has been increasing recognition of hospital wastewater as a reservoir for carbapenemase-producing Enterobacterales (CPE), including S. marcescens. Because CPE can proliferate in biofilms in sink drains and traps, controlling nosocomial spread is challenging. The ideal approach to eliminate transmission from wastewater to patients remains unknown. Methods: Patients were included if they were admitted to 1 of 2 intensive care units (ICUs) for >12 hours between December 1, 2010, and January 31, 2016. During this period at the University of Virginia Hospital, there was ongoing patient acquisition of multiple species producing Klebsiella pneumoniae carbapenemase (KPC) as well as consistent perirectal KPC surveillance. In January 2014, to eliminate CPE-colonized sinks, the sink drains and traps in one of the ICUs (ie, the “intervention unit”) were exchanged followed by varied chemical mitigations to prevent recolonization. In another ICU, the same chemical mitigations were performed but without plumbing replacement (ie, the “control unit”). Acquisition of KPC-producing S. marcescens was defined as colonization or infection >12 hours after admission to either unit. To control for increases in patient-to-patient transmission, acquisition of methicillin-resistant Staphylococcus aureus (MRSA) was evaluated in the intervention unit during the same period and was defined as new colonization or infection with MRSA >12 hours after unit admission but within 21 days of last unit exposure. Results: For the postintervention period, risk of S. marcescens acquisition was increased (RR, 2.85; 95% CI, 1.24–6.58; P = .01) in the intervention unit compared to the control unit. In the intervention unit, the risk of S. marcescens acquisition increased in the postintervention period compared to the preintervention period (RR, 6.26; 95% CI, 2.59–15.1; P < .0001). There was no change in MRSA acquisition in the intervention unit representing consistent patient-to-patient infection prevention (RR, 0.95; 95% CI, 0.61–1.48; P = .81). S. marcescens isolates were noted to be highly clonal. Conclusions: Exposure to the intervention unit following plumbing replacement was associated with increased relative risk of acquisition of KPC-producing S. marcescens. This increased risk was not observed in the control unit, which had only chemical plumbing interventions. There was no concomitant increase in patient-to-patient MRSA transmission. The disturbance of the wastewater environment through the plumbing replacement intervention may have led to the unintended consequence of more KPC-producing S. marcescens acquisition.

Disclosures: None
Electronic phenotyping of community-acquired pneumonia: A tool for inpatient syndrome-specific antimicrobial stewardship
Authors: Chang Amy , Bui Annie , Ha David , Alegria William , Holubar Marisa , Lu Brian , Mische Leah , Linfield Rebecca , Walding Kyle , Mui Emily
Published: September 2023

Background: Using patient data from the electronic health record (EHR) and computer logic, an “electronic phenotype” can be created to identify patients with community-acquired pneumonia (CAP) in real time to assist with syndrome-specific antimicrobial stewardship efforts.1 We adapted and validated the performance of an inpatient CAP electronic phenotype for antimicrobial stewardship interventions. Methods: An automated scoring system was created within the EHR (Epic Systems) to identify hospitalized patients with CAP based on the variables and logic listed in Fig. 1B. We adapted a score used by the Michigan Hospital Medicine Safety Consortium (HMS) to identify patients with CAP, with additions made to improve sensitivity (Fig. 1).1 The score can be displayed in a column within the EHR patient list (Fig. 2). We validated the electronic phenotype via chart review of all hospitalized patients on systemic antimicrobials admitted to a medicine team consecutively between November 8 and 18, 2021. Patients who were readmitted within the validation time frame were excluded. We assessed the performance of the electronic phenotype by comparing the score to manual chart review, where “CAP diagnosis” was defined as (1) mention of “pneumonia” or “CAP” as part of the differential diagnosis in the admission documentation, (2) antimicrobials were started within 48 hours of admission, and (3) radiographic findings were suggestive of pneumonia. After initial evaluation, the scoring system was adjusted, and performance was re-evaluated during prospective audit and feedback performed on EHR CAP–positive patients over 13 days between July 2022 and December 2022. Results: We included 191 patients in our initial validation cohort. The CAP score had high sensitivity (95.83%), specificity (92.2%), and negative predictive value (99.35%), though lower positive predictive value (63.89%) was noted (Table 2). The rules were further refined to include bloodstream infection only with Haemophilus influenza or Streptococcus pneumoniae in rule 2B, and azithromycin was removed from “CAP antibiotics.” After these changes, repeated evaluation of 88 patients with positive CAP EHR score was performed, and only 20 (23%) were considered false-positive results. Conclusions: Electronic phenotypes can be used to create automated tools to identify patients with CAP with reasonable performance. Data from this tool can be used to guide more focused antimicrobial stewardship interventions and clinical decision support in the future. Reference: Vaughn VM, et al. A statewide collaborative quality initiative to improve antibiotic duration and outcomes in patients hospitalized with uncomplicated community-acquired pneumonia. Clin Infect Dis 2022;75:460–467.

Disclosures: None
Non-invasive assessment of positive affective state using infra-red thermography in rats
Authors: Wongsaengchan Chanakarn , McCafferty Dominic J , Lennox Katie , Nager Ruedi G , McKeegan Dorothy EF
Published: September 2023

With recent increased focus on positive welfare in animal welfare science, there is demand for objective positive welfare indicators. It is unclear whether changes in body surface temperature can be used to non-invasively identify and quantify positive states in mammals. We recorded continuous measurements of tail surface temperature using infra-red thermography (IRT) and concurrent behavioural observations in male and female Wistar rats (Rattus norvegicus). If tail surface temperature can differentiate between positive and negative experiences, we expect a qualitatively different response compared to negative experiences. Three groups of rats were presented with increasing magnitudes of food rewards (neutral/none, one and three rewards). The rats were placed in an arena to which they were habituated and filmed for 30 s before and 30 min after exposure to different rewards. Tail temperature initially decreased from the pre-reward baseline and subsequently returned towards baseline temperature. The overall pattern of the change was the same as for rats subjected to negative stimuli in previous studies. Nevertheless, dynamic changes in tail temperature, specifically the rate of recovery and the behavioural response (exploration), differed between neutral and rewarded rats but failed to distinguish reward magnitude. Sex differences were found in both thermal and behavioural responses, unrelated to reward magnitudes. Female rats exhibited a greater initial response with a slower recovery than male rats, emphasising the value of using of both sexes in animal welfare research. This study improves our understanding of the effects of positive emotions induced by food reward on peripheral body temperature and behaviour.
Cooperation and group similarity in children and young adults in the UK
Authors: Majolo Bonaventura , Maréchal Laëtitia , Igali Ferenc , Van de Vyver Julie
Published: September 2023

For cooperation to be beneficial, cooperators should be able to differentiate individuals who are willing to cooperate from free-riders. In the absence of kin or of familiar individuals, phenotypic similarity (e.g. in terms of language) can be used as a cue of how likely two or more individuals are to behave similarly (whether they will cooperate or free-ride). Thus, phenotypic similarity could affect cooperation. However, it is unclear whether humans respond to any type of phenotypic similarity or whether only salient phenotypic traits guide cooperation. We tested whether within-group, non-salient phenotypic similarity affects cooperation in 280, 3 to 10 year old children and in 76 young adults (mean 19.8 years old) in the UK. We experimentally manipulated the degree of phenotypic similarity in three computer-based experiments. We found no evidence of a preference for, or greater cooperation with, phenotypically similar individuals in children, even though children displayed ingroup preference. Conversely, young adults cooperated more with phenotypically similar than with phenotypically diverse individuals to themselves. Our results suggest that response to non-salient phenotypic similarity varies with age and that young adults may pay more attention to non-salient cues of diversity then children.
Employer associations in light of the Great Recession and radical labour market deregulation in Southern Europe: An analysis from the perspective of company membership
Authors: Sánchez-Mosquera Marcial
Published: September 2023

This article analyses the impact of the Great Recession and radical labour market deregulation on employer associations’ (EAs) membership levels and composition in Southern Europe. It also reviews the literature and advances it in four relevant aspects. First, it verifies a general decrease in membership of EAs in Southern Europe, almost to the point of collapse in Greece. Secondly, it identifies the greater importance of large companies (more than Fordist economic sectors) in the composition of this membership. Thirdly, it confirms that sectoral bargaining (as a major determinant) and union representation (an element weakened by reforms) are strong company-level incentives for membership in EAs. Finally, it re-examines the reasons put forward in the scholarly literature to explain why EAs in Southern Europe have not been in favour of these significant institutional changes.
Controlled inertial nano-cavitation above 100 MHz
Authors: Gutiérrez-Hernández Ulisses J. , Reese Hendrik , Ohl Claus-Dieter , Quinto-Su Pedro A.
Published: September 2023

The maximum size and lifetime of an acoustically nucleated cavitation bubble is inversely proportional to the driving frequency and has achieved a limit of approximately 10 MHz. Smaller cavitation bubbles that are critical to microscopic applications require shorter lifetimes that correspond to higher oscillation frequencies. Here, we demonstrate that acoustic cavitation in the 100 MHz range and beyond can be achieved through wave propagation in a solid rather than in a liquid. The cavitation bubble is nucleated at a nano-sized fracture on a glass substrate, and its expansion is driven by a leaky Rayleigh wave, while the inertial collapse is induced by a trailing shock wave. As both waves travel at different velocities, the time interval between these two events is a function of the distance to the source. In this way, we demonstrate experimentally control of the lifetime of the bubbles in a range between 6 and 80 ns, corresponding to oscillation frequencies between 13 and 166 MHz. Our results agree with finite-volume fluid–structure interaction simulations.
Three-dimensional wake transitions of steady flow past two side-by-side cylinders
Authors: Ren Chengjiao , Liu Zinan , Cheng Liang , Tong Feifei , Xiong Chengwang
Published: September 2023

Three-dimensional (3-D) wake transitions of a steady flow past two side-by-side circular cylinders are investigated through Floquet analysis and direct numerical simulations (DNS) over the gap-to-diameter ratio

$g^*$

up to 3.5 and Reynolds number

${\textit {Re}}$

up to 400. When the flows behind two cylinders form in-phase and anti-phase wakes at large

$g^*$

, the wake transition is similar to the isolated cylinder counterpart, with the critical

${\textit {Re}}$

for the onset of 3-D transition (

${\textit {Re}}_{cr-1}$

) happens at around 180. At small

$g^*$

, 3-D transition becomes interestingly complex due to the distinct characteristics formed in base flows. The

${\textit {Re}}_{cr-1}$

suddenly drops to around 60–100 and forms distinct variation trends with

$g^*$

. Precisely, the

${\textit {Re}}_{cr-1}$

of the single symmetric wake (SS,

$g^*\lessapprox 0.25$

) is more than half of the isolated cylinder counterpart due to the large length scale of the SS wake. Only mode A is detected in SS. In the asymmetric single wake (ASS,

$g^* \approx 0.25\unicode{x2013}0.6$

) and flip-flop wake (FF,

$g^* \approx 0.6\unicode{x2013}1.8$

), the 3-D transition develops at

${\textit {Re}} \approx 103\unicode{x2013}60$

and 75–60, respectively. The decrease in

${\textit {Re}}_{cr-1}$

with increasing

$g^*$

is because of the increased level of wake asymmetry in ASS and irregular vortex shedding in FF. Floquet analysis predicts two new unstable modes, namely mode A

$'$

and subharmonic mode C

$'$

, of ASS. Both modes are transient features in 3-D DNS and the flow eventually saturates into a new 3-D mode, mode ASS. The gap flow of mode ASS is distinctly characterised by its time-independent spanwise waviness structure that is deflected towards different transverse directions with a long wavelength of about

$14$

cylinder diameters. The 3-D mode of the FF is irregular both temporally and spatially. Variations of

${\textit {Re}}_{cr-1}$

with

$g^*$

, the characteristics and the physical mechanisms of each 3-D mode are discussed in this study.
Dynamics of acoustically coupled single- and multi-port jet diffusion flames
Authors: Vargas Andres , Kiani Sarina , Hayrapetyan Arin , Karagozian A.R.
Published: September 2023

The present experimental study investigated the dynamics of single- and multi-port gaseous jet diffusion flames exposed to acoustic excitation via a standing wave situated in a closed waveguide at atmospheric pressure. High-speed imaging of the oscillatory flame was analysed via proper orthogonal decomposition (POD), revealing distinct signatures in both mode shapes and phase portraits for transitions in the acoustically coupled combustion process. For Reynolds numbers between 20 and 100, and for low to moderate forcing amplitudes, the flame exhibited sustained oscillatory combustion (SOC) that was highly coupled to the acoustic forcing. Frequency analysis of the temporal POD modes accurately recovered the forcing frequency and its higher harmonics. At higher forcing amplitudes, a multi-frequency response was observed, resulting from a combination of the forcing frequency and much lower frequency oscillations due to periodic lift-off and reattachment (PLOR) of the flame, preceding a transition to flame blow-off (BO). For both single- and triple-jet flames, transitions from SOC to PLOR to BO were characterized by significant alterations in primary modal energetic content, deflection and eventual smearing in phase portraits, and the development of additional frequencies in modal spectra, although transitional behaviour for the triple jet flames involved additional complexity in the dynamics due to its structure. These features provide the potential for the development of reduced-order models that can characterize and predict acoustically coupled combustion behaviour.