Healthcare-associated links in transmission of nontuberculous mycobacteria among people with cystic fibrosis (HALT NTM) study: Rationale and study design

Background Healthcare-associated transmission of nontuberculous mycobacteria (NTM) among people with cystic fibrosis (pwCF) has been reported and is of increasing concern. No standardized epidemiologic investigation tool has been published for healthcare-associated NTM outbreak investigations. This report describes the design of an ongoing observational study to standardize the approach to NTM outbreak investigation among pwCF. Methods This is a parallel multi-site study of pwCF within a single Center who have respiratory NTM isolates identified as being highly-similar. Participants have a history of positive airway cultures for NTM, receive care within a single Center, and have been identified as part of a possible outbreak based on genomic analysis of NTM isolates. Participants are enrolled in the study over a 3-year period. Primary endpoints are identification of a shared healthcare-associated encounter(s) among patients in a Center and identification of environmental isolates that are genetically highly-similar to respiratory isolates recovered from pwCF. Secondary endpoints include characterization of potential transmission modes and settings, as well as incidence and prevalence of healthcare-associated environmental NTM species/subspecies by geographical region. Discussion We hypothesize that genetically highly-similar strains of NTM among pwCF cared for at the same Center may arise from healthcare sources including patient-to-patient transmission and/or acquisition from environmental sources. This novel study design will establish a standardized, evidence-based epidemiologic investigation tool for healthcare-associated NTM outbreak investigation within CF Care Centers, will broaden the scope of independent outbreak investigations and demonstrate the frequency and nature of healthcare-associated NTM transmission in CF Care Centers nationwide. Furthermore, it will provide valuable insights into modeling risk factors associated with healthcare-associated NTM transmission and better inform future infection prevention and control guidelines. This study will systematically characterize clinically-relevant NTM isolates of CF healthcare environmental dust and water biofilms and set the stage to describe the most common environmental sources within the healthcare setting harboring clinically-relevant NTM isolates. Trial registration ClinicalTrials.gov NCT04024423. Date of registry July 18, 2019.

A Cluster of Coronavirus Disease 2019 (COVID-19) Cases on an Inpatient Hospital Unit Involving Multiple Modes of Transmission

Background: The Ohio State University Wexner Medical Center identified a cluster of coronavirus disease 2019 (COVID-19) cases on an inpatient geriatric stroke care unit involving both patients and staff. The period of suspected severe acute respiratory coronavirus virus 2 (SARS-CoV-2) transmission and exposure on the unit was December 20, 2020, to January 1, 2021, with some patients and staff developing symptoms and testing positive within the 14 days thereafter. Methods: An epidemiologic investigation was conducted via chart review, staff interviews, and contact tracing to identify potential patient and staff linkages. All staff who worked on the unit were offered testing regardless of the presence of symptoms as well as all patients admitted during the outbreak period. Results: In total, 6 patients likely acquired COVID-19 in the hospital (HCA). An additional 6 patients admitted to the unit during the outbreak period subsequently tested positive but had other possible exposures outside the hospital (Fig. 1). One patient failed to undergo COVID-19 testing on admission but tested positive early in the cluster and is suspected to have contributed to patient to employee transmission. Moreover, 32 employees who worked on the unit in some capacity during this period tested positive, many of whom became symptomatic during their shifts. In addition, 18 employees elected for asymptomatic testing with 3 testing positive; these were included in the total. Some staff also identified potential community exposures. Additionally, staff reported an employee who was working while symptomatic with inconsistent mask use (index employee) early in the outbreak period. The index employee likely contributed to employee transmission but had no direct patient contact. Our epidemiologic investigation ultimately identified 12 employees felt to be linked to transmission based on significant, direct patient care provided to the patients within the outbreak period (Fig. 1). In addition, 3 employees had an exposure outside the hospital indicating likely community transmission. Conclusions: Transmission was felt to be multidirectional and included employee-to-employee, employee-to-patient, and patient-to-employee transmission in the setting of widespread community transmission. Interventions to stop transmission included widespread staff testing, staff auditing regarding temperature and symptom monitoring, and re-education on infection prevention practices. Particular focus was placed on appropriate PPE use including masking and eye protection, hand hygiene, and cleaning and disinfection practices throughout the unit. SARS-CoV-2 admission testing and limited visitation remain important strategies to minimize transmission in the hospital.Funding: NoDisclosures: None

Real-world implementation and impact of a rapid carbapenemase detection test in an area endemic for carbapenem-resistant Enterobacterales

A retrospective study was conducted to describe the impact of a molecular assay to detect the most common carbapenemase genes in carbapenem-resistant Enterobacterales isolates recovered in culture. Carbapenemases were detected in 69% of isolates, and assay results guided treatment modifications or epidemiologic investigation in 20% and 4% of cases, respectively.

Investigation of the First Case of New Delhi Metallo-β-Lactamase-1–Producing Pseudomonas aeruginosa in Texas

Background: New Delhi metallo-β-lactamases impart resistance to carbapenems. Enterobacteriaceae carrying New Delhi metallo-β-lactamases have been reported before. However, only 7 cases of blaNDM-carrying Pseudomonas aeruginosa has been reported from 4 states in the United States as of January 1, 2018, according to the CDC. We describe an epidemiologic investigation of the first reported case of blaNDM-carrying Pseudomonas aeruginosa in Texas and the measures that controlled the spread of the organisms carrying this gene at a 30-bed spinal cord injury unit (SCI) and the acute-care hospital within the Veterans’ Affairs North Texas Health Care System. Methods: After identification of blaNDM-1–carrying P. aeruginosa from a urine culture in an SCI patient who received medical treatment in Thailand prior to transfer, we performed a rectal screen for the presence of blaNDM in the index patient’s hospital roommates. Based on the results, we expanded the investigation to other patient care units that had provided care to the patient. We initiated universal contact isolation precautions, 1:1 nursing care, restricted movement, phased point-prevalence testing, and intense environmental cleaning until the threat of blaNDM was mitigated. Whole-genome sequencing (WGS) was performed on clinical isolates from the index patient and the roommates by the CDC. Results: Of the 2 roommates of the index, 1 patient had a urine culture positive for blaNDM-5-carrying Escherichia coli. The second roommate has subsequently grown blaNDM-1-carrying P. aeruginosa from a clinical culture. A third patient who was in the same unit as the index patient but not in the same room in an acute-care unit tested positive for blaNDM in a rectal screen. Of the 54 patients who were hospitalized in the same unit as the index patient, 26 refused to get the test and 28 tested negative. In addition, point-prevalence rectal screening was conducted in the SCI in 3 phases that were 3 to 4 weeks apart. All of these screening tests were negative. WGS revealed that the index patient and roommate 2 had blaNDM-1–carrying P. aeruginosa, whereas the roommate 1 had blaNDM-5–carrying E. coli. No further spread occurred. Conclusions: Our aggressive efforts quickly mitigated further spread of blaNDM. Our epidemiologic investigation indicates that an intergenus transfer of blaNDM from P. aeruginosa to E. coli likely took place. In addition, it appears there was an evolution of NDM-1 to NDM-5, which differs from the former by 2 amino acid substitutions at positions 88 (Val→Leu) and 154 (Met→Leu). This type of evolution has been shown by prior studies to confer increased antibiotic resistance in certain resource limited settings.Funding: NoneDisclosures: None