Patel, Gopi

Abstract Background Carbapenem-resistant Enterobacterales (CRE) are an urgent public health threat in the United States. Objective Describe the clinical and molecular epidemiology of CRE in a multicenter pediatric cohort. Methods CRACKLE-1 and CRACKLE-2 are prospective cohort studies with consecutive enrollment of hospitalized patients with CRE infection or colonization between 24 December 2011 and 31 August 2017. Patients younger than age 18 years and enrolled in the CRACKLE studies were included in this analysis. Clinical data were obtained from the electronic health record. Carbapenemase genes were detected using polymerase chain reaction and whole-genome sequencing. Results Fifty-one children were identified at 18 healthcare system study sites representing all U.S. census regions. The median age was 8 months, with 67% younger than age 2 years. Median number of days from admission to culture collection was 11. Seventy-three percent of patients had required intensive care and 41% had a history of mechanical ventilation. More than half of children had no documented comorbidities (Q1, Q3 0, 2). Sixty-seven percent previously received antibiotics during their hospitalization. The most common species isolated were Enterobacter species (41%), Klebsiella pneumoniae (27%), and Escherichia coli (20%). Carbapenemase genes were detected in 29% of isolates tested, which was lower than previously described in adults from this cohort (61%). Thirty-four patients were empirically treated on the date of culture collection, but only 6 received an antibiotic to which the CRE isolate was confirmed susceptible in vitro. Thirty-day mortality was 13.7%. Conclusions CRE infection or colonization in U.S. children was geographically widespread, predominantly affected children younger than age 2 years, associated with significant mortality, and less commonly caused by carbapenemase-producing strains than in adults.

Abstract Background Carbapenem-resistant Acinetobacter baumannii (CRAb) is 1 of the most problematic antimicrobial-resistant bacteria. We sought to elucidate the international epidemiology and clinical impact of CRAb. Methods In a prospective observational cohort study, 842 hospitalized patients with a clinical CRAb culture were enrolled at 46 hospitals in five global regions between 2017 and 2019. The primary outcome was all-cause mortality at 30 days from the index culture. The strains underwent whole-genome analysis. Results Of 842 cases, 536 (64%) represented infection. By 30 days, 128 (24%) of the infected patients died, ranging from 1 (6%) of 18 in Australia-Singapore to 54 (25%) of 216 in the United States and 24 (49%) of 49 in South-Central America, whereas 42 (14%) of non-infected patients died. Bacteremia was associated with a higher risk of death compared with other types of infection (40 [42%] of 96 vs 88 [20%] of 440). In a multivariable logistic regression analysis, bloodstream infection and higher age-adjusted Charlson comorbidity index were independently associated with 30-day mortality. Clonal group 2 (CG2) strains predominated except in South-Central America, ranging from 216 (59%) of 369 in the United States to 282 (97%) of 291 in China. Acquired carbapenemase genes were carried by 769 (91%) of the 842 isolates. CG2 strains were significantly associated with higher levels of meropenem resistance, yet non-CG2 cases were over-represented among the deaths compared with CG2 cases. Conclusions CRAb infection types and clinical outcomes differed significantly across regions. Although CG2 strains remained predominant, non-CG2 strains were associated with higher mortality. Clinical Trials Registration. NCT03646227.

Abstract Background Carbapenem Resistant Enterobacterales (CRE) are an urgent public health threat. We describe the clinical and molecular epidemiology of CRE infection in a multicenter pediatric cohort. Methods Patients under 18 years of age with CRE positive cultures between April 30 2016 and August 31 2017 were identified from among 49 hospitals participating in the Consortium on Resistance Against Carbapenems in Klebsiella and Other Enterobacteriaceae. Isolates representing colonization or infection were included. Bacterial identification and antimicrobial susceptibility testing were performed in each contributing clinical microbiology laboratory. Carbapenem resistance was defined per CDC criteria as those isolates displaying imipenem, doripenem, or meropenem MIC ≥4 μg/mL or ertapenem MIC ≥2 μg/mL. Clinical and epidemiological data were obtained from the electronic health record. Carbapenemase genes were detected using PCR. Results 51 pediatric patients with CRE were identified at 17 hospitals. All regions of the United States were represented, with highest prevalence in the South (46%), followed by the Northeast (24%), Midwest (20%) and West (10%). The mean age at time of positive culture was 4 years. 66% of children were under age 2. 53% were male. 40% were white, 38% black, and 18% Hispanic. Mean time from admission to culture was 25 days. 72% of children were in an ICU at the time of culture, including 18% in the neonatal ICU. 42% required mechanical ventilation prior to culture. History of malignancy was present in 14% of children. The most common source was urine (31%), followed by respiratory (25%), and blood (18%). The most common species were Enterobacter cloacae (29%), Klebsiella pneumoniae (24%) and E. coli (20%). Carbapenemase genes were detected in 8 out of 35 (23%) isolates tested. 90-day mortality was 18%. Mortality was highest for K. pneumoniae (42%). The majority of subjects (88%) did not receive effective antibiotic therapy on the day of culture collection. Table 1 Table 2 Conclusion CRE infection or colonization in children in the U.S. was geographically widespread, likely hospital-acquired, and associated with high mortality. A significant portion of patients were infants. Ineffective antibiotic therapy was common at illness onset. Disclosures W. Charles Huskins, MD, MSc, ADMA Biologics (Consultant)Pfizer, Inc (Consultant)

AbstractBackgroundHematopoietic stem cell transplant (HSCT) recipients have increased morbidity from respiratory viral infections. Pandemic influenza A – A(H1N1)/pdm09 – in 2009–2010 was associated with increased severity of illness in patients with underlying co‐morbidities including HSCT, but the factors that contribute to severe disease in HSCT patients are not well characterized.MethodsWe conducted a multicenter review of microbiologically proven influenza A(H1N1)pdm09 in the HSCT population between April 2009 and April 2010 to determine factors that are associated with severe disease.ResultsWe identified 37 adult patients (26 allogeneic and 11 autologous HSCT recipients). Median time from transplant to diagnosis was 411 days (range 4 days–14.9 years). Three cases were hospital acquired. Twenty‐eight of 37 (75.7%) had confirmed A(H1N1)pdm09. Presumed viral lower respiratory tract infection was present in 12/37 (32.4%) patients. Antiviral therapy was given to 33/37 (89%) patients, primarily oseltamivir (n = 24) and oseltamivir before or after another antiviral (n = 8). Excluding those with nosocomial A(H1N1)pdm09, 18/34 (52.9%) were hospitalized and 6 (33%) required admission to an intensive care unit. Mortality within 30 and 60 days of symptom onset was 7/37 (18.9%) and 11/37 (29.7%), respectively. Factors associated with mortality included nosocomial acquisition (P = 0.023), receipt of mycophenolate mofetil (P = 0.001), or antilymphocyte antibody (P = 0.005) within the past 6 months, reduced‐intensity conditioning (P = 0.027), and bacteremia (P = 0.021).ConclusionsA(H1N1)pdm09 infection was particularly severe in HSCT recipients, specifically among those receiving augmented immunosuppression for graft‐versus‐host disease. The high mortality of the nosocomial cases highlights the need for strict infection‐control measures in hospitals during influenza outbreaks.