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 Standardization of MIC breakpoints across clinical laboratories is lacking; AST instruments are often validated for outdated Clinical and Laboratory Standards Institute (CLSI) MIC breakpoint guidelines.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

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

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

We observed that patients admitted to our hospital from a prestratified group of congregated living facilities had a numerically higher percentage of study-defined resistant organisms in sputum cultures compared to facilities without these characteristics [89.4% vs 78.3%, odds ratio [OR] = 2.34 (95% CI, 0.73–7.58)].

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a major cause of bloodstream infection among hospitalized patients in low- and middle-income countries (LMICs). CRAB infections can be difficult to treat and are devastating in neonates (~30% mortality). CRAB outbreaks are hypothesized to arise from reservoirs in the hospital environment, but outbreak investigations in LMICs seldom incorporate whole-genome sequencing (WGS). Methods: WGS (Illumina NextSeq) was performed at the National Institute for Communicable Diseases (South Africa) on 43 preserved A. baumannii isolates from a 530-bed referral hospital in Gaborone, Botswana, from March 2021–August 2022. This included 23 blood-culture isolates from 21 unique patients (aged 2 days–69 years) and 20 environmental isolates collected at the 36-bed neonatal unit in April–June 2021. Infections were considered healthcare-associated if the culture was obtained >72 hours after hospital arrival (or sooner in inborn infants). Blood cultures were incubated using an automated system (BACT/ALERT, BioMérieux) and were identified using manual methods. Environmental isolates were identified using selective or differential chromogenic media (CHROMagarTM). Taxonomic assignment, multilocus sequence typing (MLST), antimicrobial resistance gene identification, and phylogenetic analyses were performed using publicly accessible analysis pipelines. Single-nucleotide polymorphism (SNP) matrices were used to assess clonal lineage. Results: All 23 blood isolates and 5 (25%) of 20 environmental isolates were confirmed as A. baumannii; thus, 28 A. baumannii isolates were included in the phylogenetic analysis. MLST revealed that 22 (79%) of 28 isolates were sequence type 1 (ST1), including all 19 healthcare-associated blood isolates and 3 (60%) of 5 environmental isolates. Genes encoding for carbapenemases (blaNDM-1, blaOXA-23) and biocide resistance (qacE) were present in all 22 ST1 isolates; colistin resistance genes were not identified. Phylogenetic analysis of the ST1 clade demonstrated spatial clustering by hospital unit. Related isolates spanned wide ranges in time (>1 year), suggesting ongoing transmission from environmental sources (Fig. 1). An exclusively neonatal clade (0–2 SNPs) containing all 8 neonatal blood isolates was closely associated with 3 environmental isolates from the neonatal unit: a sink drain, bed rail, and a healthcare worker’s hand. Conclusions: WGS analysis of clinical and environmental A. baumannii revealed the presence of unit-specific CRAB clones, with evidence of ongoing transmission likely driven by persistent environmental reservoirs. This research highlights the potential of WGS to detect hospital outbreaks and reaffirms the importance of environmental sampling to identify and remediate reservoirs (eg, sinks) and vehicles (eg, hands and equipment) within the healthcare environment.

Disclosures: None

Background: Veterans Health Administration (VHA) community living centers (CLCs) provide postacute and long-term care. CLC veterans visit myriad locations outside their rooms (eg, rehabilitation, dialysis). Pathogen transmission during out-of-room visits is unknown. Methods: We recruited newly admitted veterans at 3 CLCs. After obtaining informed consent, we cultured nares, groin, hands, and 7 surfaces in the patient rooms. We accompanied veterans to up to 5 out-of-room visits and cultured patients’ hands and surfaces they touched. We tested for multidrug-resistant organisms (MDROs) including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and quinolone, carbapenem, and/or ceftazidime-resistant gram-negative bacteria (R-GNB). We defined transmission as a positive culture following an initial negative culture during the same visit. Results: We enrolled 137 veterans (median follow-up, 29 days; mean, 5.9 visits); 97% were postacute patients. We conducted 539 patient-room sampling visits (mean, 3.9 per veteran; 5,490 swabs) and accompanied 97 veterans to 266 out-of-room sampling visits (mean, 2.7 per veteran; 2,360 swabs). Of 137 patients, 47 (35%) were colonized with an MDRO at enrollment and 74 (58%) of 128 patients were colonized on any follow-up patient-room visits. Of 133 patients, 55 (41%) acquired a new MDRO, most often VRE (31 of 97, 32%). In patient rooms, toilet seats [114 (21%) of 538], curtains [101 (19%) of 530] and bedrails [98 (18%) of 539] were most frequently contaminated. Among 266 out-of-room visits, 17% had surfaces contaminated with MDROs, most commonly involving dialysis [4 (31%) of 13], radiology [2 (25%) of 8], and rehabilitation therapy [29 (18%) of 159] (Fig. 1).Transmission of MDROs during out-of-room visits was common and occurred in 18% of visits with 8% (9 MRSA and 12 VRE) acquiring a new MDRO on their hands and 12% (9 MRSA and 23 VRE) of MDRO transmission occurring from hands to a surface that the patient touched (Fig. 1). In 18 (58%) of 31 cases, the organism transmitted to a surface was on patient hands at the start of the visit. Transmission was most common during visits to dialysis (3 to patients and 2 to surfaces), radiology (1 to a patient and 2 to surfaces), and rehabilitation therapy (13 to patients and 21 to surfaces) (Fig. 2). Conclusions: New MDRO acquisition during VHA CLC stay was common, and nearly one-fifth of out-of-room visits resulted in MDRO transmission. Our analyses suggest that veterans’ hands may shed MDROs (MRSA and VRE) to surfaces. Interventions to reduce MDRO transmission during visits for rehabilitation, dialysis, and other therapies are needed.

Disclosures: None

Appropriateness of transmission-based precautions after positive result for a non-SARS-CoV-2 virus was evaluated. Most patients (77.2%) lacked appropriate precautions within 3 hours of virus detection; 36.9% remained without appropriate precautions during their stay. With recent cessation of universal masking, adherence to infection control best practices is needed to optimize safety.

Background: COVID-19 has presented hospitals with unique challenges. An SHEA Research Network survey showed that 40% reported “limited” or worse levels of personal protective equipment (PPE) and that 13% were self-producing PPE to address those deficits, including 3D-printed items. However, we do not know how efficiently, if at all, 3D-printed materials can be disinfected. Additionally, 2 filaments, PLACTIVE and PUREMENT, claim to be antimicrobial; they use copper nanocomposites and silver ions to reduce bacterial populations. We assessed how PLACTIVE and PUREMENT may be contaminated and how well they reduce contamination, and how readily polylactic acid (PLA), a standard 3D-printed material, may be disinfected. Methods: We grew methicillin-resistant and -susceptible Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae on 3D-printed disks and conducted bacterial survival assays to determine whether bacteria grow on PLA, PLACTIVE, and PUREMENT. We performed a time series (with 3- and 24-hour dry times) followed by serial dilutions to attain colony-forming unit (CFU) averages for each strain per disk. To determine whether 3D-printed material can be cleaned, we used 70% EtOH on PLA only. We conducted the same time series followed by a disinfectant time series (with dry times 30 seconds, 2.5, minutes, 5 minutes, and 10 minutes). Again, serial dilutions were performed to attain the PLA CFU averages with disinfectant. The CFU averages from the control group (PLA) and testing group (PLACTIVE and PUREMENT) were compared to see how well the antimicrobial material decreased bacterial load. We also compared the CFU averages of PLA with and without disinfectant to see how well 70% EtOH decreased bacterial load. Results: 3D-printed material is readily contaminated with bacteria common in hospitals and can sustain that contamination. Antimicrobial materials, PLACTIVE and PUREMENT, had lower levels of bacterial contamination when compared to PLA. However, disinfected disks had lower overall CFU averages than those that were not, but the level of disinfection was variable and bacterial populations recovered hours after disinfection application. Conclusions: Proper disinfection and using appropriate 3D-printed materials are essential to limiting bacterial contamination. 3D printers and their products can be invaluable for hospitals, especially when supplies are low and healthcare worker safety is paramount. Environmental services should be made aware of the presence of antimicrobial 3D-printed materials, and patients should be discouraged from printing their own items for use in hospital environments.

Disclosures: None

Background: Statistically significant decreases in methicillin-resistant Staphylococcus aureus (MRSA) healthcare-associated infections (HAIs) occurred in Veterans Health Administration (VA) facilities from 2007 to 2019 using active surveillance for facility admissions and contact precautions for patients colonized (CPC) or infected (CPI) with MRSA, but the value of these interventions is controversial. Objective: To determine the impact of active surveillance, CPC, and CPI on prevention MRSA HAIs, we conducted a prospective cohort study between July 2020 and June 2022 in all 123 acute-care VA medical facilities. In April 2020, all facilities were given the option to suspend any combination of active surveillance, CPC, or CPI to free up laboratory resources for COVID-19 testing and conserve personal protective equipment. We measured MRSA HAIs (cases per 1,000 patient days) in intensive care units (ICUs) and non-ICUs by the infection control policy. Results: During the analysis period, there were 917,591 admissions, 5,225,174 patient days, and 568 MRSA HAIs. Only 20% of facilities continued all 3 MRSA infection control measures in July 2020, but this rate increased to 57% by June 2022. The MRSA HAI rate for all infection sites in non-ICUs was 0.07 (95% CI, 0.05–0.08) for facilities practicing active surveillance plus CPC plus CPI compared to 0.12 (95% CI, 0.08–0.19; P = .01) for those not practicing any of these strategies, and in ICUs the MRSA HAI rates were 0.20 (95% CI, 0.15–0.26) and 0.65 (95% CI, 0.41–0.98; P < .001) for the respective policies. Similar differences were seen when the analyses were restricted to MRSA bloodstream HAIs. Accounting for monthly COVID-19 admissions to facilities over the analysis period using a negative binomial regression model did not change the relationships between facility policy and MRSA HAI rates in the ICUs or non-ICUs. There was no statistically significant difference in monthly facility urinary catheter-associated infection rates, a nonequivalent dependent variable, in the categories during the analysis period in either ICUs or non-ICUs. Conclusions: In Veterans Affairs medical centers, there were fewer MRSA HAIs when facilities practiced active surveillance and contact precautions for colonized or infected patients during the COVID-19 pandemic. The effect was greater in ICUs than non-ICUs.

Disclosures: None

Background: Candida auris, an emerging and potentially multidrug-resistant fungus, was first identified in Maricopa County, Arizona, in 2020. On April 21, 2022, an acute-care hospital reported C. auris in a bronchoalveolar lavage (BAL) specimen, followed by a second case reported on April 26 identified via retrospective laboratory review and species identification in yeast isolated from a clinical specimen. The Maricopa County Department of Public Health (MCDPH) investigated, and we describe the largest ongoing C. auris outbreak containment response in Maricopa County. Methods: The MCDPH conducted clinical case and contact investigations in accordance with CDC novel organism containment strategy guidelines. In Maricopa County healthcare facilities (HCFs) with suspected transmission, virtual Infection Control Assessment Responses (ICARs) were administered to identify initial infection prevention and control (IPC) gaps; subsequent regular virtual visits were also provided. HCFs with confirmed transmission completed point-prevalence surveys (PPSs) every 2 weeks until transmission halted as evidenced by 2 sequential negative PPSs. Outreach education to affected HCFs was provided to increase awareness about the public health significance of C. auris and the importance of implementation and sustained adherence to standardized IPC protocols. Results: In total, 97 HCFs received IPC outreach education, of which 22 HCFs (23%) had suspected transmission and received a virtual ICAR. Contact investigation identified 1,990 contacts, of whom 1,028 (52%) were discharged to the community, 863 (43%) were admitted to other HCFs, and 99 (5%) died. Of the 863 transferred contacts, 10 (1.2%) declined colonization screening, 853 (98.8%) were screened, and 46 (5%) tested positive for C. auris. Through sequential PPSs, 101 (5%) of 1,914 screened patients tested positive for C. auris. By December 31, 16 clinical and 147 colonized cases were epidemiologically linked to the outbreak. Their median age was 60 years (IQR, 20), and 3 pediatric cases (median age, 17 years) were identified with no pediatric unit admissions. Also, 7colonized cases (5%) developed noninvasive infection and 3 (2%) developed candidemia. Conclusions: The MCDPH’s established partnerships with HCFs were key to this ongoing C. auris outbreak response spanning 22 facilities over 8 months. Challenges included delays in specimen collection and laboratory processing, operational burden of repeated PPS, and ensuring appropriate precautions for readmitted close contacts at subsequent HCFs. The MCDPH assisted facilities in balancing public health surveillance with facility capacity to execute guidance, including repeated PPS. Consistent adherence to stringent IPC practices, interfacility communication, and proactive C. auris education of healthcare workers are paramount to halting transmission.

Disclosures: None

Background: Candida auris is a frequently drug-resistant yeast that can cause invasive disease and is easily transmitted in healthcare settings. Pediatric cases are rare in the United States, with <10 reported before 2022. In August 2021, the first C. auris case in Las Vegas was identified in an adult. By May 2022, 117 cases were identified across 16 healthcare facilities, including 3 pediatric cases at an acute-care hospital (ACH) with adult cases, representing the first pediatric cluster in the United States. The CDC and Nevada Division of Public and Behavioral Health (NVDPBH) sought to describe these cases and risk factors for C. auris acquisition. Methods: We defined a case as a patient’s first positive C. auris specimen. We reviewed medical records and infection prevention and control (IPC) practices. Environmental sampling was conducted on high-touch surfaces throughout affected adult and pediatric units. Isolate relatedness was assessed using whole-genome sequencing (WGS). Results: All 3 pediatric patients were born at the facility and had congenital heart defects. All were aged <6 months when they developed C. auris bloodstream infections; 2 developed C. auris endocarditis. One patient died. Patients overlapped in the pediatric cardiac intensive care unit; 2 did not leave between birth and C. auris infection. Mobile medical equipment was shared between adult and pediatric patients; lapses in cleaning and disinfection of shared mobile medical equipment and environmental surfaces were observed, presenting opportunities for transmission. Overall, 32 environmental samples were collected, and C. auris was isolated from 2 specimens from an adult unit without current cases. One was a composite sample from an adult patient’s bed handles, railings, tray table and call buttons, and the second was from an adult lift-assistance device. WGS of specimens from adult and pediatric cases and environmental isolates were in the same genetic cluster, with 2–10 single-nucleotide polymorphisms (SNPs) different, supporting within-hospital transmission. The pediatric cases varied by 0–3 SNPs; at least 2 were highly related. Conclusions: C. auris was likely introduced to the pediatric population from adults via inadequately cleaned and disinfected mobile medical equipment. We made recommendations to ensure adequate cleaning and disinfection and implement monitoring and audits. No pediatric cases have been identified since. This investigation demonstrates transmission can occur between unrelated units and populations and that robust infection prevention and control practices throughout the facility are critical for reducing C. auris environmental burden and limiting transmission, including to previously unaffected vulnerable populations, like children.

Disclosures: None

An outpatient parenteral antimicrobial therapy team from a Veterans Affairs facility managed patients discharged from their own facility and neighboring community hospitals. There were no significant differences in adverse outcomes between the groups, but a majority of regimens were modified from those initially proposed by community providers.

Background: Measles is a highly transmissible respiratory virus that presents with nonspecific prodromal symptoms followed by a characteristic cephalocaudal rash. In the prodromal phase, children with measles can be challenging to differentiate from children with other circulating respiratory viral infections. A measles outbreak in Central Ohio starting in October 2022 coincided with a national surge in children with viral respiratory infections which presented unique challenges in preventing healthcare transmission in the pediatric ambulatory setting. Methods: Following initial identification of presumed community transmission of measles in Central Ohio in November 2022, a multidisciplinary measles response team was convened at Nationwide Children’s Hospital (NCH) to prevent secondary healthcare transmission via rapid-cycle quality improvement. Prevention efforts were focused broadly across NCH ambulatory locations in Central Ohio, including the main campus and offsite emergency departments, regional urgent cares, and primary care network. Preliminary risk factors were identified via chart review of initial cases, which included vaccine status, ZIP code of residence, and known daycare or household exposure. These risk factors were used to guide an intervention bundle comprising enhanced screening at registration and triage, creation of electronic medical record alerts to identify at-risk patients, increased clinician education, and expanded community messaging. As the outbreak evolved, risk factors were updated, and interventions were adjusted to adapt response. Outcome metrics included total patient exposures as well as the relative exposure score. The exposure score was an internal metric derived using the vaccine status of exposed patients and ventilation at the site of exposure to assess likelihood of secondary cases occurring from an exposure. Results: In total, 65 patients with measles were seen at NCH facilities between October 29 and December 8, 2022. The outbreak response was divided into 4 periods: (1) cases identified retrospectively prior to first diagnosis (October 29–November 7, 2022), (2) initial case discovery (November 8–14, 2022), (3) implementation of prevention bundle (November 15–28, 2022), and (4) updates to the response (November 29–December 8, 2022). Ambulatory healthcare exposures and incidence of secondary cases decreased over the outbreak periods in response to implementation of the prevention bundle (Fig. and Table). Conclusions: An outbreak of measles occurring simultaneously with peak respiratory viral season presented challenges in early identification of suspected cases and mitigation of healthcare exposure. Transmission was effectively prevented following rapid deployment of a prevention bundle adjusted in real-time through rapid-cycle quality improvement. Ongoing longitudinal vaccination efforts are needed to sufficiently mitigate transmission risk in communities with under-vaccinated populations.

Disclosures: None