Background: Nontuberculous mycobacteria (NTM) are ubiquitously found throughout the environment, including healthcare facilities, and disproportionately affect immunocompromised hosts. We have a limited understanding of healthcare-associated transmission. Detailed outbreak investigations may yield insights into transmission risk. Method: An investigation of a Mycobacterium abscessus outbreak began after identifying a higher-than-expected frequency of infections among solid organ transplant recipients in September 2024. Cases were defined as individuals with a first-time positive M. abscessus culture from any anatomical site and a prior inpatient admission to our hospital. Our epidemiologic investigation included creating a case line list with potential exposures during the 90 days preceding microbiologic diagnosis, direct observations of patient care, a case-control study to identify potential point sources and transmission routes, and environmental cultures to test source/transmission hypotheses. Whole-genome sequencing (WGS) of case isolates was performed to confirm genetic relatedness (defined as ?10 single nucleotide variant difference). Prospective microbiologic surveillance was used to identify new cases. Result: Between May 2023 and the ongoing investigation through December 2025, 31 cases were identified. Twenty (65%) were solid organ transplant recipients, including 12 (60%) lung transplants (Figure 1, Table 1). Our epidemiologic investigation did not identify any other geographic, procedural, or point source exposures with commonality among <20% cases. The case-control study identified transplant status as a significant risk factor for transmission. We hypothesized transmission occurred through contaminated water exposure in inpatient rooms during routine care; environmental cultures demonstrated M. abscessus in potable water sources throughout the hospital (Figure 2). WGS identified 2 distinct clusters comprising 3 and 14 patients, with genetic relatedness to environmental M. abscessus isolates. Sequential flushing and chlorination of the facility-wide water system were performed without significant changes in the frequency of NTM isolation. To mitigate exposure risk, point-of-use filters were installed and tap water avoidance was enforced on units predominantly caring for patients with immunocompromising conditions. Following implementation of tap water avoidance, only 4 genetically related cases have been identified within 11 months of follow-up. Conclusion: Water exposure during routine patient care among susceptible hosts increases NTM risk. Eradication of NTM from aging plumbing systems is challenging; tap water avoidance combined with POU filtration appeared to have abated this outbreak. Infection prevention programs should consider routine monitoring of NTM infection rates, particularly M. abscessus, to detect a higher-than-expected frequency. Routine water quality surveillance should include NTM cultures. Studies are needed to identify effective methods of NTM eradication from potable water supplies.

Background: Early identification of severe sepsis or septic shock in the emergency department (ED) is challenging; patients triaged to the waiting room commonly encounter hours of delay before provider evaluation. Although vital signs and laboratory testing may be obtained at check-in, patients may deteriorate during this waiting period, and so there is a critical need for indicators of occult disease. Common inflammatory biomarkers such as C-reactive protein (CRP) are sensitive but poorly specific in undifferentiated ED populations and offer limited value for early risk stratification. We evaluated the diagnostic performance of an FDA-cleared host-response RNA biomarker assay (SeptiCyte RAPID) for identifying severe sepsis or septic shock prior to clinician evaluation. Method: As part of a multi-phase validation study, we conducted a prospective observational cohort study at a tertiary-care ED. During predefined monthly windows we consecutively enrolled adult patients (≥18 years) if they: were triaged for suspected infection, had ≥2 systemic inflammatory response syndrome (SIRS) criteria, blood drawn at triage, and were initially placed in the waiting room or non-treatment areas. The SeptiCyte assay was performed as an add-on study using blood already collected, with clinicians blinded to results. Severe sepsis or septic shock was adjudicated retrospectively using standardized SEP-1 abstraction criteria published by the Centers for Medicare and Medicaid Services (CMS). Diagnostic performance was assessed using sensitivity, specificity, area under the receiver operating characteristic curve (AUC), and likelihood ratios. Likelihood ratios were contextualized against published CRP performance in undifferentiated ED populations. Result: We enrolled 101 patients in this phase, and at a prespecified higher-risk threshold, SeptiCyte demonstrated a sensitivity of approximately 0.59 and specificity of 0.77, with an AUC of 0.69 and a positive likelihood ratio of 2.6. In comparison, published CRP performance in similar undifferentiated ED populations is characterized by AUCs ranging from approximately 0.60–0.68 and positive likelihood ratios ≤2.0, reflecting lower specificity. Conclusion: In triaged ED patients with suspected infection awaiting emergency provider evaluation, a host-response RNA biomarker demonstrated moderate discrimination for subsequent severe sepsis or septic shock with operating characteristics favoring specificity and rule-in capability. Compared with published CRP performance, the biomarker appears better suited for early risk stratification and flag earlier clinician evaluation rather than broad inflammatory screening in ED waiting-room populations.

Background: Following the COVID-19 pandemic, the University of Kentucky (UKY) experienced elevated rates of methicillin-resistant Staphylococcus aureus (MRSA). To drive rapid improvement, an MRSA escalation program was developed incorporating targeted contact precautions for units not meeting decolonization thresholds, enhanced MRSA surveillance testing, and data-driven reports to support unit leadership. Methods: The UKY Infection Prevention and Control Program (IPAC) implemented a data-driven MRSA escalation strategy. At baseline, all patients in intensive care units, patients with indwelling lines or tubes, and patients testing positive for MRSA were expected to undergo daily chlorhexidine bathing and intranasal povidone iodine decolonization. Upon review, gaps were identified in decolonization performance and screening of at-risk populations. The intervention addressed these gaps by including electronic health record (EHR)–prompted MRSA screening for at-risk patients, development of aggregate decolonization compliance dashboards, and real-time performance dashboards for unit supervisors. A monthly decolonization performance threshold of 70 percent was established. Units with persistent compliance below 70 percent were placed on contact precautions with an “MRSA Escalation” designation in the EHR. IPAC met with identified units to provide toolkits and education on dashboard utilization and integration of MRSA metrics into routine huddles and sprints. In March 2025, intranasal decolonization was transitioned from povidone iodine to mupirocin. Monthly hospital-onset MRSA bacteremia counts, chlorhexidine bathing compliance, and nasal decolonization compliance from July 2023 through December 2025 were analyzed using simple linear regression with time in months as the independent variable. Results: Multidisciplinary education was conducted across nursing, physician, and leadership groups from August 2023 through January 2024, with program go-live in February 2024. Chlorhexidine bathing compliance increased significantly over time, with an average improvement of 0.39 percentage points per month (95% CI 0.24–0.55, p < 0.001, R² = 0.48, Figure 1). Nasal decolonization compliance also increased significantly, with an average improvement of 0.30 percentage points per month (95% CI 0.16–0.44, p < 0.001, R² = 0.40). Hospital-onset MRSA bacteremia demonstrated a significant downward trend (slope –0.089 cases per month, p = 0.012, R² = 0.20), corresponding to an average reduction of approximately one case every 11 months. Quarterly SIR decreased from 1.10 in Q3 2023 to 0.54 in Q4 2025. Conclusions: Implementation of an MRSA escalation program incorporating decolonization performance thresholds, targeted contact precautions, enhanced education, real-time data reporting, and transition to mupirocin for nasal decolonization was associated with significant improvements in decolonization compliance and a sustained reduction in hospital-onset MRSA bacteremia.

This review considers the current status, and highlights existing knowledge gaps, on Antarctic terrestrial and freshwater biological responses to climate change. Climate change is considered to be one of the major drivers of future ecosystem change in Antarctica. Understanding the biological responses, and associated shifts in biodiversity patterns, biotic interactions and processes, that are likely to occur under continued climate change is fundamental for predicting its consequences for the functioning of Antarctic ecosystems. However, quantifying changes in species abundance, biodiversity, community composition and biotic interactions, and how these are influenced by variations in a multitude of environmental variables, is challenging. All biological groups in the Antarctic terrestrial and freshwater domains currently show low species richness at higher latitudes, indicating that there should be scope for lower-latitude species to expand their distributions southwards under warming conditions. The northern, ‘trailing edge’ or lower altitudinal limits may also shift southwards or upwards, respectively. However, to date, only one report exists of increased diversity within field experimental warming studies, and none exist from the few available long-term monitoring sites. Similarly, while notable plant-cover expansions have been recorded at some localized sites, no clear large-scale vegetation response has been documented within recognized Antarctic biological regions, while organisms living within the vegetation show highly variable responses. There are still many knowledge gaps on this matter for various biological groups across and within Antarctic regions. While it is frequently posited that the potential for climate change-driven range expansion and biodiversity shifts is substantial, the biological responses reported to date indicate that current levels of climate change have not (yet) resulted in large-scale changes in abundance and biodiversity patterns across Antarctica.

Background: Microbiome disruption is linked to risk of mortality and infection. Measuring the impact of patient-level antibiotic exposure to microbiome disruption is needed to inform stewardship and microbiome restoration therapy efforts. The National Healthcare Safety Network (NHSN) standard, days of therapy (DOT), widely used to capture antibiotic use, does not account for spectrum of activity. Other metrics better account for spectrum, including antibiotic spectrum coverage (ASC), antibiotic spectrum index (ASI), and anaerobic activity index (AAI) – and with NHSN antibiotic groups (Clostridioides difficile infection [CDI] high risk, and broad-spectrum hospital-onset infections [BSHO]). We compared DOT with spectrum-weighted metrics to determine which best track patient-level microbiome disruption. Method: We retrospectively analyzed peri-rectal swab metagenomic data and antibiotic use for acute and long-term care facility patients. Shannon diversity index, pathogen abundance, and butyrate-producing bacterial abundance were calculated for each participant. Antibiotic exposure within 30 and 90 days prior to sampling were summarized six ways: crude duration – DOT for all antibiotics, NHSN-CDI antibiotics, and NHSN-BSHO antibiotics (all unweighted) and three weighted DOT values (sum of weights per day for each ASC, ASI, and AAI) across all days in the exposure window, accounting for antibiotic spectrum. Spearman correlations were calculated among all six antibiotic metrics and between the metrics and microbiome disruption features. Result: One hundred participants were included with median 30-day and 90-day DOT of 16 (IQR:6-31) and 27 (IQR: 13-64), respectively. Weighted metrics (ASC, ASI, AAI) demonstrated strong correlations with each other (Figure 1, darker orange). Crude duration metrics (DOT, CDI, BSHO) were only moderately correlated with weighted metrics (Figure 1, lighter orange). Shannon diversity was correlated with all exposure metrics except the NHSN CDI high-risk group, and AAI had the strongest association (30-day r=-0.41, p Conclusion: Patient-specific weighted DOT of antibiotic exposure, in particular the AAI weights, correlates with gut microbiome disruption well. Interestingly, the NHSN high-CDI-risk antibiotic group did not. Patient-level 30-day exposure had similar observed correlations as 90-day exposure windows and may be a practical window to measure microbiome antibiotic effects. Further study is needed to test causality of identified associations, the influence of absolute vs relative abundance measures, and best ways to incorporate these measures into stewardship efforts and identification of microbiota therapy candidates.

Introduction: The American College of Obstetricians and Gynecologists (ACOG) and Society of Healthcare epidemiology (SHEA) recommend cephalosporins as the standard antibiotic for preoperative prophylaxis for abdominal hysterectomy (AH-includes Laparoscopic and open cases) . However, anaerobic organisms are prevalent in vaginal and intraabdominal flora and can contribute to development of surgical site infections (SSIs). Limited data suggest that including anaerobic coverage may reduce SSI risk. In May 2024, we implemented anaerobic containing regimens as first-line preoperative antibiotic prophylaxis for all AH cases. This study evaluates whether adding anaerobic coverage to the preoperative antibiotic protocol reduces National Healthcare Safety Network (NHSN)-defined SSI after AH surgeries. Methods: We conducted a retrospective cohort study of all patients who underwent inpatient or outpatient from January 2023 through September 2025. Preoperative antibiotic choice and timing as well as patient demographics and comorbidities were obtained from medical records. SSI were determined by NHSN definitions by trained infection preventionists. First line antibiotics with anaerobic coverage were defined as cefazolin plus metronidazole, or vancomycin plus aztreonam plus metronidazole in patients with penicillin allergies. SSI in patients who received first line antibiotics with anaerobic coverage were compared to those who received alternative antibiotic regimens (Around 80% of alternative regimen consisted of only cefazolin). Multivariate logistic regression and overlap weighting methods were applied to evaluate the independent impact of first-line therapy. Results: Among 11,444 hysterectomy procedures, the overall SSI rate was 1% (n=109 cases). Unadjusted SSI rate in patients receiving first-line antibiotics was significantly lower than those receiving alternate prophylaxis (0.7% vs 1.3 %, p =0.001). Individuals who received first-line antibiotics were generally younger, more frequently identified as Caucasian, and exhibited greater rates of diabetes and cancer compared to those who received alternative regimens. Patients who received first line antibiotics also had longer surgeries, a higher frequency of elective and laparoscopic procedures, and higher rates of adherence to preoperative protocols such as chlorhexidine bathing, vaginal preparation, and maintenance of normothermia (see Table 1). After adjusting for baseline differences between groups through multivariate logistic regression and overlap weighting, first-line therapy was associated with a 50% reduction in SSI risk compared to alternative regimens (OR 0.51; 95% CI 0.34–0.76; p=0.001). (Table 2) Conclusion: Compared to alternative regimens for preoperative antibiotic prophylaxis, the routine inclusion of metronidazole to cefazolin was associated with a reduced risk of SSI following AH surgeries even after adjusting for demographic, procedural and clinical differences between groups.

Background: After CDC and local surveillance identified an increase in Klebsiella pneumoniae carbapenemase (KPC)-producing carbapenem-resistant Enterobacterales (KPC-CRE) caused by multiple organisms, an investigation was conducted at an acute care hospital. Cases clustered around an intensive care unit (ICU) and step-down unit (SDU), where wastewater plumbing was a suspected transmission source. Whole genome sequencing (WGS) was used to investigate this outbreak. Methods: A case was defined as detection of KPC-CRE or KPC (no organism cultured) from specimens collected at the hospital between 01/2019 to 10/2025. Clinical cases were identified via carbapenemase testing of CRE isolates using PCR (Xpert Carba-R) or by multiplex PCR panels and screening cases through PCR with reflex to culture. ICU sink and hopper samples and SDU sink samples were tested using selective media, MALDI-TOF, and multiplex PCR for KPC-CRE detection. Isolates underwent short and long-read sequencing. Result: Overall, 64 cases (37 clinical; 27 screening), involving 54 patients, were identified; 28 patients had ICU/SDU admissions during their hospitalization. The 52 cases with an organism identified included seven species, of which the most common were Citrobacter (26), Klebsiella (14), and Raoultella (5); 24 harbored blaKPC-2 (37.5%), 18 blaKPC-4 (28.1%), 5 blaKPC-3 (7.8%), 1 blaKPC-160 (1.5%), and 16 were not subtyped (25%). Seventeen isolates from five species carried blaKPC-2 on a 42 kb IncP6 plasmid, while ten isolates from five species carried blaKPC-4 on a 69 kb plasmid with Col440I and IncM1 replicons. Environmental sampling in 05/2025 found KPC-CRE in 10/12 sinks and 2/12 hoppers in the ICU and 1/22 SDU sinks (fig1). KPC-CRE environmental isolates were closely genetically related to the Citrobacter, Klebsiella, and Roultella clinical isolates and harbored similar KPC-carrying plasmids. Infection prevention and control (IPC) rounding identified patient items within the sink splash zone, including placing bath-in-a-bag in the sink. In 05/2025, a campaign was initiated to remove items from the splash zone, switch to chlorhexidine wipes, and implement daily use of an EPA-registered, sodium dichloroisocyanurate-based biofilm drain disinfectant product. Starting 07/2025, pouring of lipids and total parenteral nutrition down drains was stopped. While repeat environmental sampling in 6/2025 also found KPC-CRE in sink drains, no additional cases were identified in the ICU or SDU following these remediation activities (fig2). Conclusion: ICU sinks served as a reservoir for KPC-CRE, with transmission to patients. KPC-CRE persisted in drains following initial drain disinfection measures; therefore, changes in sink and splash-zone IPC practices appear to be important for interrupting transmission.

Background: Companion animals, including dogs and cats, can harbor pathogenic microorganisms that affect animal health and pose potential zoonotic risks to humans. The U.S. National Action Plan for Combating Antimicrobial Resistance, grounded in the One Health framework, emphasizes collaboration across human, animal, and environment health sectors and calls for improved veterinary oversight of antimicrobial use (AMU). However, contemporary data describing veterinary AMU remain limited, particularly in academic veterinary settings. Methods: This cross-sectional retrospective study analyzed encounter data obtained from a Michigan veterinary teaching hospital between June 2022 to May 2025. Companion animal patients were categorized as dogs or cats. De-identified data included demographics, encounter characteristics, service types, reasons for visit, antimicrobial agents, routes of administration, and treatment durations. Only encounters with ≥1 antimicrobial prescription were included. Descriptive analyses were performed, and proportions were reported with 95% Wilson confidence intervals (CIs) where applicable. Results: A total of 14,010 encounters, representing 17% (95% CI, 16.8-17.2) of all encounters, involved at least one antimicrobial prescription. These encounters corresponded to 12,401 unique patients, of whom 75.6% were dogs and 24.4% were cats. A lower proportion of dogs were neutered compared with cats (74.5% [95% CI, 73.6-75.4] vs 84.2% [82.9-85.5]). The median patient age was 6.0 years (IQR, 2.2-10.0). Emergency and critical care accounted for 44.4% (95% CI, 43.7-45.1) of antimicrobial-associated encounters, and wellness/follow-up visits were the most common encounter type in both species (38.3% [95% CI, 37.6-39.1]). Compared with dogs, cats more frequently presented for respiratory conditions (10.0% [95% CI, 9.6-10.6] vs 23.5% [22.0-25.0]) and urinary tract disease (9.9% [9.4-10.4]) vs 21.8% [20.4-23.3]). Dogs received more antimicrobial prescriptions per patient than cats (2.49 [95% CI, 2.43-2.56] vs 1.73 [1.60-1.79]), and ≥4 prescriptions per visit were more common in dogs (16.7% [15.9-17.4] vs 4.7% [4.0-5.5]). Amoxicillin-clavulanate accounted for over half of the oral antimicrobial prescriptions in dogs (55.4%, 4,697/8,474) and cats (59.6% [1,608/2,699); cats were associated with a longer treatment of amoxicillin-clavulanate (median 7 days [IQR 7-14] vs 10 days [IQR 7-10]). Fluoroquinolones were the second most common agents in both species, with prolonged duration observed, particularly for pradofloxacin in cats (median 60 days [IQR, 12-60]). Conclusions: Antimicrobial prescribing was common among companion animals, with frequent use of broad-spectrum agents and prolonged treatment durations. These findings highlight opportunities for veterinary antimicrobial stewardship, including diagnostic-linked prescribing, duration optimization, and reduction of empiric and repetitive AMU, particularly in outpatient and emergency care settings.

Background: Central line-associated bloodstream infections (CLABSIs) remain a challenge in pediatric intensive care units (PICUs); central line days have been directly correlated with risk of CLABSI. The Mayo Clinic PICU is a 23-bed multidisciplinary unit including dedicated bone marrow transplant beds with an average of 1048 admissions annually. In 2024, the unit’s CLABSI rate was 0.82 per 1,000 central line days or approximately 1–3 CLABSIs per year. Weekly multidisciplinary CLABSI Prevention Rounds were piloted from August 2024 to March 2025 with the aim of reducing central line device utilization rate as a method to reduce CLABSI risk. Methods: A multidisciplinary team of Clinical Nurse Specialists (CNS), Nurse Managers, and off-service PICU physicians conducted weekly CLABSI rounds on PICU beds (excluding 4 BMT beds), meeting with each bedside nurse as well as the on-service providers. The CLABSI team assessed central line necessity using a standard questionnaire and provided education to physicians and nurses regarding central line care and CLABSI prevention. Monthly data were compared for the same 8 calendar months pre versus post intervention for central line days, patient days, and device utilization rate (DUR; central line days/patient days), both unadjusted and adjusted for PRISM (Pediatric Risk of Mortality) 3 severity of illness score. Pre- and post-implementation staff surveys assessed confidence in line management and interdisciplinary communication using Likert scales. Results: Thirty-two CLABSI rounds with a total of 118 individual patients and 45 discrete interventions were noted over 8 months and compared to the 8 pre-intervention corresponding months. Pre versus post monthly DUR was 0.42 [0.32–0.57] vs 0.46 [0.30–0.55], p = 0.49 (PRISM 3–adjusted p = 0.97). Nursing confidence in ‘discussing central line need’ significantly improved post-implementation, 5 [4–5] vs 5 [5–5], p = 0.035. Nurses also positively perceived third-party involvement in need assessment, 4 [3–4] vs 4 [3–4], p = 0.06. All surveyed clinicians trended toward being less likely to think a central line was left in too long, 3 [3–4] vs 3 [2–4], p = 0.06. Conclusion: Structured weekly multidisciplinary CLABSI rounds are a feasible intervention that empowers bedside nurses and improves confidence in line maintenance and interdisciplinary communication. Median DUR was not significantly altered by the intervention, but nursing perception of central line management improved qualitatively in pre- versus post-implementation surveys. Continued expansion of multidisciplinary initiatives addressing central line necessity and management is needed to further evaluate overall effects on DUR and CLABSI incidence.

Background: Clostridioides difficile is a spore-forming bacterium that causes severe healthcare-associated infections, especially in immunocompromised patients and those exposed to antibiotics. C.difficile spores can persist in the environment, making routine use of sporicidal disinfectants essential for reducing contamination and infection risk. Surgical and patient mattresses, while impervious, are soft and flexible and generally do not meet the U.S Environmental Protection Agency (EPA) definition of a hard, nonporous surface, which is the surface type typically used to test disinfectant efficacy. Assessing spore survival and disinfectant performance on these soft surfaces is important for minimizing transmission risk, especially since they are often treated like hard surfaces. Methods: Antimicrobial efficacy testing was conducted using common healthcare disinfectants against C.difficile, following standard operating procedures typically required for EPA registration. Spores were inoculated and dried onto stainless steel coupons (hard surface control) and multiple soft surface coupons made of common mattress cover materials. Each disinfectant formulation represented a common active ingredient or blend of active ingredients, ranging from ready-to-use sprays to wipes. Products were tested at approximately 90% of the manufacturer-defined contact times to stress the chemistry and reveal any efficacy differences between the different surface types. Results: Significant C.difficile Log reductions were observed with disinfectant Products 1, 2, 3, and 4, demonstrating high efficacy against C.difficile. Product 5, a non-sporicidal disinfectant commonly used on mattress covers, demonstrated little to no reduction of C.difficile. Conclusion: Using standard benchtop testing methods, this study aimed to understand the efficacy of sporicidal healthcare disinfectants against C.difficile on common soft surface materials. While EPA-registered disinfectants may be intended for hard, nonporous surfaces, the use of sporicidal disinfectants on mattresses may be more effective at reducing the risk of infection than traditionally thought, especially since these soft surfaces cannot be laundered. This is particularly important during outbreaks and underscores the proactive use of sporicidal disinfectants to mitigate C.difficile and other emerging pathogens.

Background: Urinary tract infections (UTIs) are frequently managed at outpatient settings, including primary care and urgent care (UC) clinics and emergency departments (EDs), which vary in antibiotic prescribing practices. We aimed to evaluate initial antibiotic choice and clinician responsiveness to cultures in subsequent days after the encounter by clinical setting. Methods: This retrospective cohort study included encounters with an order for a urinalysis with reflex urine culture from June 1, 2022 to June 30, 2024 across 29 walk-in and retail clinics (UCs), 5 EDs, and 33 primary care clinics at Vanderbilt University Medical Center. All encounters included antibiotics received with an order indication for cystitis or pyelonephritis (UTI). Encounters in which a positive urine culture was available in the preceding 6 months were excluded, as it was assumed that this data would guide antibiotic selection and therefore would not be empiric. Additionally, encounters from June to December 2022 were removed because culture data in the preceding six months could not be assessed. For each time period, antibiotic use was recorded as administered or not administered during Day 0-1 (empiric therapy) and Days 2-5 (culture-directed therapy). Patients could receive <1 antibiotic per time period per encounter. Differences in antibiotic prescribing were calculated using Chi-square and Fisher’s exact tests as indicated. Results: A total of 20,889 encounters were included: 5,750 (27.5%) from ED, 12,912 (61.8%) from UC, and 2,227 (10.7%) from primary care. Empiric antibiotic choice differed significantly for all antibiotics across clinical settings. Higher rates of prescribing cephalexin and third generation oral cephalosporins occurred in the ED, and fluoroquinolones in primary care, while lower use of nitrofurantoin was noted in the ED (Figure 1). A total of 256/5,750 (4.5%) patients at the ED, 1,258/12,912 (9.7%) at UCs, and 203/2,227 (9.1%) at primary care received at least one subsequent antibiotic (Figure 2). Compared to the ED, a higher percentage of both UC and primary care patients received culture-responsive antibiotics. Antibiotic choice patterns were similar for empiric and culture-responsive antibiotics. Conclusion: Higher percentages of culture-responsive antibiotic prescriptions were noted for primary care and UC compared to ED. At the time of this study, UCs had dedicated nurses following up results, a system more closely mirroring procedures at primary care clinics, likely resulting in more follow up antibiotic changes. Significant differences were seen across all settings for both empiric and culture-responsive antibiotic choices and represent future targets for antimicrobial stewardship.

Background: Infection preventionists (IPs) increasingly lead systemwide healthcare epidemiology functions integrating infection prevention, antimicrobial stewardship, and preparedness for emerging pathogens. The Advanced Leadership Certification in Infection Prevention and Control (AL-CIP) is the first credential to formally assess advanced IPC leadership competencies, yet the leadership practices, epidemiologic decision-making, and risk management strategies employed by certified professionals have not been empirically described. Methods: The Leadership Evaluation and Development for Infection Preventionists (LEAD-IP) study used an observational nested cohort design. Secondary portfolio data from AL-CIP applicants across two 2025 certification cycles were analyzed to characterize demographic and professional attributes. A nested cohort of certified professionals (18%) completed a structured 60-minute qualitative interview via Microsoft Teams. Interviews followed the IRB-approved 34-item LEAD-IP instrument assessing leadership behaviors, healthcare epidemiology decision-making, antimicrobial stewardship engagement, risk assessment practices, communication strategies, and preparedness for emerging pathogens. Data were managed in REDCap and analyzed using Braun and Clarke’s inductive thematic analysis with a structured codebook, triangulation, and verification of thematic saturation. Results: Thirty AL-CIP–certified leaders across healthcare systems, public health agencies, and academic settings participated. Across seven themes, participants described a shift from task-based practice to systems-level healthcare epidemiology leadership, integrating surveillance data, antimicrobial resistance patterns, and organizational risk indicators into strategic direction-setting. Leaders emphasized dashboards, analytic tools, and improvement models to detect outbreaks earlier, evaluate stewardship interventions, and guide resource allocation. Transparent communication and psychological safety facilitated early escalation of HAI clusters, antibiotic misuse, environmental risks, and emerging pathogen concerns such as Candida auris. Participants reported persistent public health infrastructure limitations, including fragmented reporting pathways, inconsistent data-sharing with health departments, and delays in organism identification that impeded timely epidemiologic response. Significant antibiotic stewardship gaps were also identified—particularly limited analytic capacity, insufficient infectious disease support, and low organizational prioritization. Structural barriers such as staffing shortages and limited protected time constrained proactive IPC and stewardship leadership. Inclusive engagement of under-resourced teams improved situational awareness and intervention success. Proactive risk management—monitoring construction, airflow disruptions, MDRO trends, and public health alerts—was viewed as essential. AL-CIP certification strengthened leadership identity, credibility, and strategic influence. Conclusions: AL-CIP–certified professionals demonstrated advanced capabilities in healthcare epidemiology, antibiotic stewardship, and public health preparedness through systems thinking, data-driven decision-making, inclusive engagement, and proactive risk management. The AL-CIP credential enhanced leaders’ confidence and organizational impact, supporting a more resilient and prepared healthcare epidemiology workforce.

Background: Candidozyma auris is an emerging multidrug-resistant organism often associated with multi-facility outbreaks. We identified an outbreak in southeast Georgia spanning September 2024-August 2025. Although early response efforts focused on one long-term acute care hospital (LTACH) with extensive colonization, clinical cases were also identified in four acute care hospitals (ACHs), another LTACH, and one outpatient center within the public health district. Two ACH laboratories were only speciating Candida from blood cultures. We expanded the investigation to assess whether inter- and intra-facility transmission contributed to ongoing spread, to inform targeted testing, colonization screening, and infection control recommendations. Method: Colonization was detected in LTACH-A-LTACH-B via Polymerase Chain Reaction by Tennessee Laboratory Services, and clinical cases were identified via MALDI-TOF spectrometry at the Georgia Public Health Laboratory or clinical laboratories. Whole-genome sequencing (WGS) was conducted on 24 isolates. Clade data were analyzed alongside patient healthcare exposure histories to identify transmission clusters. Case data were managed in Excel, and healthcare exposure networks were visualized using visNetwork in RStudio. Result: C. auris cases were identified across 7 facilities, including ACH-A-ACH-D, LTACH-A-LTACH-B, and Outpatient-A. We identified 26 clinical and 62 screening cases. Clinical specimen sources included 31% blood, 27% wound, 23% urine, 15% respiratory, and 4% unknown. LTACH-A identified 3 clinical cases in Oct./Nov. 2024, leading to screening identifying 60 cases between 12/3/24-8/5/25. Of 60 screening cases in LTACH-A, 37% had prior exposure to ACH-A, 25% ACH-B, 17% ACH-C, and 2% ACH-D. 17 clinical cases were identified in ACH-A-ACH-D between 9/4/24-7/23/25; no screening was conducted. Review of patient healthcare exposure history uncovered 12 overlap clusters of 2-6 cases: 8 ACH-A (multiple high-acuity unit overlaps), 3 ACH-B (ICU & Med/Surg), and 1 ACH-C (no shared unit). Clinical cases in each cluster overlapped with ≥1 cases that later screened positive in LTACH-A. WGS results showed 10 (42%) clade-I and 14 (58%) clade-III. 3 ACH clusters were identified with clade-III cases, 4 had clade-I and clade-III, and 7 lacked WGS results. Conclusion: Integration of healthcare network analysis with limited WGS data demonstrated that C. auris transmission occurred within ACHs and across the public health district, rather than confined to one LTACH. Patient overlap clusters and temporal sequencing of clinical ACH cases preceding LTACH-A colonization results supported ACH-driven transmission contributing to downstream spread. These findings informed targeted recommendations for speciating non-blood cultures, implementing admission screening at ACHs, and increasing WGS capacity to strengthen multi-facility outbreak detection and response.

Background: Endometritis is one of the most common perinatal complications, affecting 7.0% of cesarean deliveries occurring after the onset of labor and 0.2-2.0% of vaginal deliveries. Chorioamnionitis increases the likelihood of delivery via cesarean section and the risk of subsequent postoperative endometritis. The addition of chorioamnionitis to the 2026 National Healthcare Safety Network (NHSN) definitions for infections present at the time of surgery (PATOS) aligns surveillance methods with a common mechanism for post cesarean endometritis, which NHSN defines as an organ space surgical site infection (SSI). Methods: This retrospective, observational study evaluated 6,340 cesarean deliveries at an academic medical center in the United States from January 1, 2019 through September 30, 2025. Cases were identified via electronic chart review using the NHSN criteria for endometritis. Results: During the study period, 59 organ space SSIs were identified, accounting for 0.9% of cesarean deliveries. Seventy-three percent of the organ space SSIs met the definition of endometritis (n=41). Chorioamnionitis was suspected in 14.6% (n=6) of the endometritis cases at the time of their cesarean delivery. Among the cases with chorioamnionitis, 66.7% (n=4) had documentation within the operative note that would meet the updated NHSN requirements for PATOS. Other documentation was included in progress notes following the procedure, which would not qualify for PATOS criteria. Subclinical chorioamnionitis was detected on placental pathology in three additional cases. Compared to the average onset for all postoperative endometritis cases (5.3 days), patients with suspected chorioamnionitis had an earlier onset (1.5 days). Over a third (34.1%) of endometritis cases were identified on postoperative day 0 or 1 (n=13). Chorioamnionitis was suspected in 21.4% of these early endometritis cases. Conclusion: The addition of chorioamnionitis to the PATOS definitions for surgical site infections reduced cesarean delivery SSI rates by 10.2% at our center and marks an alignment of surveillance and clinical definitions. In adopting this new definition into surveillance practices, obstetric and infection control teams should collaborate to ensure appropriate identification of chorioamnionitis cases, particularly when considering onset of endometritis in the early postoperative period.

Background: Antibiotic allergy evaluation is an important antibiotic stewardship intervention, but is less commonly integrated into inpatient oncology care. Our objective was to evaluate the acceptability and feasibility of a pharmacist-driven penicillin allergy delabeling intervention for patients with hematologic malignancy (HM). Methods: We conducted a cross-sectional survey of physicians and advanced practice providers (APPs) who care for patients with HM at the Hospital of the University of Pennsylvania. The survey was administered from March 2025 to September 2025 in preparation for a planned Allergy Delabeling in Antibiotic Stewardship (RENEW) intervention. The survey included questions on current allergy evaluation practices, the perceived safety of RENEW and validated acceptability of intervention measure (AIM) and feasibility of intervention measure (FIM). AIM and FIM consist of 4 items scored 1-5 and is reported as a mean total score (5-20), with higher scores indicating greater acceptability and feasibility. Data were analyzed using descriptive statistics. Result: Of 70 eligible prescribers, 27 (38.6%) completed the survey: 21 (77.7%) physicians and 6 (22.2%) APPs. The majority (20, 74.1%) reported assessing documented antibiotic allergies of HM patients on admission and at the time an antibiotic is required (25, 92.6%). Nineteen (70.4%) respondents were comfortable modifying a documented antibiotic allergy in the medical record based on their assessment, while just under half (13, 48.1%) were comfortable deleting the allergy in the record based on their assessment. Nineteen (70.4%) respondents felt that penicillin skin testing was safe in patients with HM while 8 (29.6%) were not sure. Over half (14, 51.9%) were unsure if it is safe to evaluate penicillin allergy using an oral challenge based on clinical history without a skin test. The majority (22, 81.5%) said they would be comfortable having a patient’s antibiotic allergy removed from the medical record following negative allergy testing in the RENEW intervention. Compared to other patient safety initiatives, 24 (88.9%) believed evaluating documented antibiotic allergies is important or very important. Mean totals (SD; range) for acceptability and feasibility of the RENEW intervention were AIM, 17.2 (3.5; 8-20) and FIM, 17.7 (3.1; 8-20). Conclusion: Although the low response rate may limit generalizability, the majority of inpatient oncology clinicians perceived that a penicillin allergy delabeling intervention for patients with HM was acceptable and feasible to implement. Overall, clinicians believed that evaluating antibiotic allergy labels in patients with HM is an important and safe initiative, yet there was some uncertainty regarding the safety of a direct oral challenge.

Background: National Healthcare Safety Network (NHSN) data demonstrate substantial declines over time in most hospital-acquired infections (HAIs). In contrast, surgical site infection (SSI) rates have remained largely unchanged, raising concerns regarding the effectiveness of current prevention strategies. Public reporting and pay-for-performance programs primarily focus on Centers for Medicare & Medicaid Services (CMS)–mandated procedures, notably abdominal hysterectomy (HYST) and colon surgery (COLO). It remains unclear whether stagnant SSI rates reflect trends limited to these procedures or represent a broader phenomenon across surgical populations. We sought to determine whether temporal stagnation in SSI rates is confined to CMS-mandated procedures. Methods We conducted a retrospective cohort study using the Duke Infection Control Outreach Network (DICON) database, which includes standardized NHSN SSI surveillance data from participating hospitals. We included hospitals that were continuously enrolled in DICON for the entire study period (January 1, 2020–December 31, 2024). Procedures were excluded if a hospital performed fewer than 100 of a given procedure type in any calendar year. NHSN procedure categories were excluded entirely if <1,000 procedures were performed during the study period. Procedures were grouped as Group 1 (CMS-mandated HYST and COLO) and Group 2 (all other included procedures). Temporal trends in SSI rates were assessed using regression-based models with an interaction term between calendar year and procedure group, adjusting for age, sex, and wound class. Results A total of 64 hospitals met the inclusion criteria. The final dataset included 561,811 total procedures, of which 71,573 (12.7%) were in Group 1 (HYST/COLO) and 490,238 (87.3%) were in Group 2. SSI rates were 3.49 per 100 procedures in Group 1 and 0.77 per 100 procedures in Group 2. (Figure 1) Over the study period, annual SSI rates did not change significantly in Group 1 (annual rate ratio [aRR] 1.03; 95% CI 0.99–1.06, p=0.06) or Group 2 ([aRR] 1.01; 95% CI .98-1.03). (Figure 2) Moreover, there was no significant difference in annual SSI rates between COLO/HYST and other procedures (difference in annual trend aRR 0.98; 95% CI 0.94–1.02; p=0.25). Discussion In this multicenter analysis, stagnation in SSI rates was observed among both CMS-mandated procedures and non-mandated surgical procedures, suggesting that stable SSI rates reflect broader challenges in SSI prevention rather than artifacts related to surveillance or reporting. These findings highlight the need for novel, risk-adjusted prevention strategies.

Background: Many laboratories have shifted from traditional culture-based to molecular panel diagnosis of gastrointestinal (GI) pathogens for a broad array of reasons including simplicity and rapidity. The Portland VA Health Care System (VAPORHCS) implemented the Biofire® Film array® GI pathogen panel (Biofire GI panel) 05/2024. In 04/2024, a recall alert was issued regarding increased risk of false positive norovirus results alongside a recommendation to confirm positive results by another method. The aim of this quality improvement project was to evaluate the false positive rate for norovirus of this assay. Methods: We used microbiology laboratory records to identify all norovirus positive results on the Biofire GI panel from 05/2024-09/2025. Chart review was performed to determine confirmatory norovirus test results, testing location (outpatient, inpatient, or emergency department), compatible clinical symptoms (acute nausea/vomiting/diarrhea), and the presence of other positive stool testing results. False positive was defined as discrepant Biofire GI panel (positive) and dedicated norovirus PCR (negative) results on the same sample. Result: We identified 39 initial positive tests on the Biofire GI panel from 38 unique patients. One test was excluded due to specimen processing error on the confirmatory test, leaving 38 tests for analysis. Of these, 13 (34%) were confirmed as positive by single-plex PCR corresponding to a false positive rate of 66%. False positive rate stratified by test location are shown in Figure 1. Compatible symptoms stratified by test results are shown in Figure 2. Of the true positive group, 11/13 (85%) had diarrhea < 5 days compared to 6/25 (24%) in the false positive group (p<0.001). Similarly, in the true positive group, 11/13 (85%) of patients had nausea/vomiting compared to 5/25 (20/%) in the false positive group (p<0.001). An alternative enteric pathogen was identified in 8/38 (21%) cases. Conclusion: We found an alarmingly high rate of false positive norovirus results on the Biofire GI panel at our center, which is higher than previously reported. True positive tests were more likely to be accompanied by those that fit with typical symptoms. Positive norovirus results from the Biofire GI panel should be interpreted with caution as is recommended by the manufacturer, particularly in absence of a compatible clinical syndrome.

Objective: To address the recurrent contamination of handwashing sinks with Pseudomonas aeruginosa (PA) in the Pediatric Intensive Care Unit (PICU), evaluate the PA elimination efficacy of different disinfectants and disinfection methods, and optimize disinfection strategies to prevent PA colonization and transmission, thereby reducing the risk of healthcare-associated infections (HAIs)? Methods: Nine handwashing sinks in the PICU (August–December 2024) were selected, meeting the criteria of three consecutive positive PA detections, usage frequency ≥20 times/day, and no prior special disinfection interventions (excluding those with recent pipe replacement or structural damage). They were divided into three groups (3 sinks per group). Three disinfectants were prepared: 500 mg/L chlorine-containing disinfectant, 0.5% benzalkonium chloride disinfectant, and 75% ethanol stock solution. Three disinfection methods were applied: rinsing method (disinfectant flushing for 1 minute twice daily at 5 L/min), soaking method (full coverage soaking with disinfectant for 30 minutes every morning followed by flushing), and slow-release soaking method (slow injection of disinfectant into the trap for 30-minute soaking, 10-minute standing, then flushing at 2 L/min). Samples were collected from the overflow outlet, drain, and other sites before disinfection, 1 minute after disinfection, and 24 hours after disinfection. Colony counting was performed using the pour plate method, PA was identified via the VITEK 2 system and mass spectrometry, and statistical analysis was conducted with SPSS 26.0 (α=0.05). Results: 75% ethanol showed the best immediate effect (colony count <0.1 CFU/cm² and PA detection rate 0% 1 minute after disinfection, P<0.001) but PA reoccurred at 24 hours. Chlorine-containing disinfectant performed stably (colony count reduced to 0.2 CFU/cm², PA detection rate 0%, P=0.002) with the optimal 24-hour bacteriostatic effect. Benzalkonium chloride had weak efficacy (colony count reduced to 5.0 CFU/cm², PA detection rate 33.3%). The soaking method and slow-release soaking method were significantly more effective in biofilm removal than the rinsing method (e.g., no PA detected with chlorine-containing disinfectant soaking method and <10% recurrence rate at 24 hours, compared to 66.7% PA positivity rate with the rinsing method at 24 hours), and the soaking method was more operable. Conclusion: For PA-contaminated handwashing sinks in the PICU, the chlorine-containing disinfectant soaking method has the best comprehensive effect, combining strong bactericidal power, good long-term bacteriostatic effect, and high operability. It is suitable as a routine disinfection scheme to prevent PA colonization in the ward, providing support for HAI prevention and control. Future research can explore more disinfection methods for ward sinks.

Background: Antimicrobial resistance (AMR) is a growing global health threat, yet surveillance systems remain heavily centered on clinical reporting and often overlook environmental transmission pathways. Urban rivers receiving mixed municipal, hospital, and agricultural inputs may act as important reservoirs and dissemination routes for antibiotic resistance genes (ARGs), particularly in resource-limited settings. Understanding spatial patterns of environmental resistomes is essential for advancing One Health–informed AMR surveillance. Methods: We conducted a longitudinal, multi-site investigation of ARG occurrence along the Cuautla River, an urban watershed in Morelos, Mexico, serving the resource-limited city of Cuautla. Surface water samples were collected across six locations spanning urban upstream (L1-2), urban core (L3-5), and urban downstream zones (L6) (Figure 1). Targeted droplet digital PCR (ddPCR) was used to quantify relevant ARGs, including Gram-positives (mecA and vanA), Gram-negatives beta-lactamases (CTX-M and SHV), AmpC-type β-lactamase (CMY), and Carbapenemase (KPC, NDM, VIM, IMP, and OXA-48), tetracycline (tetW) and Polymyxin-resistant (MCR-1). Physicochemical parameters and fecal indicator bacteria were measured concurrently to contextualize microbial contamination. Spatial and temporal trends in ARG abundance and composition were evaluated using non-parametric statistical analyses. Results: ARGs were widely detected across the watershed, with particularly high abundances of tetW, CMY, TEM, and multiple Gram-negative carbapenemase genes, including KPC, OXA-48, and VIM. The plasmid-mediated colistin resistance gene mcr-1 was also detected at multiple sites, highlighting the environmental presence of resistance determinants associated with last-resort antimicrobials (Figure 2). ARG abundances generally increased from urban upstream to urban downstream locations, likely reflecting cumulative inputs from domestic wastewater, healthcare facilities, and densely populated areas. Although ARG loads peaked within the urban core, elevated resistance signals remained detectable in downstream urban edge regions (Figure 3). In contrast to largely compliant physicochemical conditions, fecal indicator bacteria revealed pervasive microbial contamination across urban sites. Conclusions: Our findings demonstrate extensive resistome contamination within an urban river system, encompassing both environmental and clinically important ARGs. The spatial accumulation of resistance signals downstream and the detection of colistin resistance genes underscore the role of river ecosystem as conduits linking human activity to broader environmental AMR dissemination. These results highlight the need to integrate environmental water surveillance into AMR monitoring frameworks and support a One Health approach that connects wastewater management, antibiotic stewardship, and public-health protection in resource-limited settings.