bluuebunny/crossref_metadata_2025_split huggingface dataset:
707. Clarifying the Role of CrrB in Polymxyin-resistant Klebsiella pneumoniae Clinical Isolates Utilizing a Novel CRISPR-Cas9 System
Authors: McConville Thomas , Giddins Marla , Macesic Nenad , Uhlemann Anne-Catrin 
Published: November 2018

Abstract

Background
Polymyxin resistance (PR) threatens the mainstay of therapy for carbapenem-resistant Enterobacteriaceae (CRE) infections. While mgrB disruption accounts for most cases of PR, missense mutations in crrB have been proposed as an alternative pathway for PR through PmrA/B/C upregulation of the pmrHFIJKLM operon. It remains unknown if CrrB acts as a positive or negative regulator on its downstream targets.

Methods
We assembled a CRISPR-Cas9 system for gene knockouts (KO) in CRE K. pneumoniae (CRKP) using zeocin as a selectable marker. We chose a polymyxin susceptible (PS) and a PR isolate with a missense mutation in crrB (L87V) (NR5337 and NR5083, respectively) for KO. Isolates were transformed with a crrB KO plasmid, grown with zeocin selection, induced with arabinose, and plated on low-salt LB-zeocin/arabinose. KOs were confirmed via PCR and Sanger sequencing. Polymyxin susceptibility was performed with broth-microdilution. Gene expression was determined by qRT-PCR of cDNA extracts.

Results
Colistin MIC following crrB KO of NR5337 (PS) remained unchanged. In contrast, crrB KO of NR5083 (PR), decreased polymyxin MIC (MIC &gt;128 to 1.0 μg/mL). qRT-PCR of NR5083 did not show increased expression of pmrA/C, nor pmrK. NR5083 ^crrB showed a small decrease in phoQ expression, compared with NR5083, but similar expression of phoP, pmrA/C and pmrK (Table 1).

Conclusion
Polymyxin MIC decreased &gt;128 fold after crrB KO in a PR isolate, but colistin MIC remained unchanged after KO in a PS isolate. CrrB mutations in PR isolates may confer a gain of function with CrrB acting as a positive regulator on its downstream targets. Contrary to previous literature, no upregulation of pmrA/C and pmrHFIJKLM was detected. Differences in crrB mutations or clonal background may explain this finding. CRISPR-Cas9 may serve as a reliable system for genetic manipulation of CRKP. Further data on the impact of individual crrB missense mutations are needed.

Disclosures
A. C. Uhlemann, Merck: Investigator, Grant recipient.
708. Incidence and Relatedness of Carbapenemase-Producing Carbapenem-Resistant Enterobacteriaceae Infections in Previously Colonized or Infected Patients
Authors: Tang Sarah Si Lin , Teo Jocelyn , Chlebicki Piotr , Kwa Andrea L 
Published: November 2018

Abstract

Background
In patients with history of carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CPCRE), the need for CPCRE targeted treatment in subsequent sepsis episodes is unclear. We determine the likelihood of CPCRE infection (CI) in patients previously colonized (PC) or infected (PI) with CPCRE and relatedness of both episodes.

Methods
Adult inpatients with CPCRE isolated from any site in June 2012–May 2014 at a tertiary-care hospital were prospectively followed for 2 years to assess for subsequent CI. Bacteria isolates from paired episodes were subjected to Illumina HiSeq2500 and multilocus sequence typing.

Results
Six of 25 (24%) PI and 11 of 152 (7%) PC patients had subsequent CI—overall incidence was 9.6%. KP was most commonly implicated. While bacteria species differed in four cases, the carbapenemase type was conserved in all but one. Those with initial bacteremia, intra-abdominal (IA) or lung infection (n = 6) were five times more likely to develop CI. Only 33% of PI vs. 62% of PC patients had subsequent infections of the same clonal group. For PC, KP (OR 9.3) and OXA carbapenemase (OR 12.8) significantly predicted for subsequent CI. In PI, chronic renal failure requiring dialysis (OR 70.2) and KPC enzyme (OR 14) were predisposing factors. In-hospital mortality was observed in six cases.

Conclusion
Incidence of CI in carriers is low. Patients with IA and respiratory CI in the preceding 93 days are candidates for CPCRE treatment; empiric therapy should be active against the carbapenemase identified in the index episode.

Disclosures
All authors No reported disclosures.
710. Increased Clinical Failure Rates Associated with Reduced Metronidazole Susceptibility in Clostridioides difficile
Authors: Gonzales-Luna Anne , Shen Wan-Jou , Dotson Kierra , Lancaster Chris , Endres Bradley , Hossain Feroz , Begum Khurshida , Cernoch Patricia , Perez Katherine , Tisdel Naradah , Barrett Miriam , Muldrew Kenneth L , Alam M Jahangir , Garey Kevin , Hurdle Julian 
Published: November 2018

Abstract

Background
Current national guidelines suggest limiting metronidazole (MTZ) use due to increased treatment failures in patients with Clostridioides difficile infections (CDI). However, the reason for these increased failure rates is unclear. We hypothesized an increase in the minimum inhibitory concentration (MIC) of MTZ to C. difficile may contribute to these poor response rates. The objective of this study was to examine clinical response rates in patients with CDI who received MTZ monotherapy vs. other therapies stratified by MTZ susceptibility.

Methods
Stool samples that tested positive for C. difficile (2017–2018) were collected from two large academic hospital systems in Texas. C. difficile was isolated from stool and visually screened for growth on heme-containing agar plates with MTZ at 2 mg/L (defined as reduced susceptibility). Blinded investigators reviewed electronic medical records to identify the treatment received and determine clinical success or failure for each patient. Treatment failure rates were assessed in patients that received MTZ monotherapy vs. other therapies stratified by MTZ susceptibility. Results were analyzed using multivariate logistic regression analysis.

Results
A total of 172 C. difficile isolates were included of which 55.8% displayed reduced susceptibility to MTZ. Clinical success rates with MTZ varied based on disease severity (mild-moderate: 80.4%; severe/severe-complicated: 64%). Treatment success rates were higher in patients infected with MTZ susceptible isolates (88.4%) compared with those infected with isolates showing reduced MTZ susceptibility (60.5%; P = 0.004.) In multivariate logistic regression after controlling for disease severity, patients infected with strains displaying reduced MTZ susceptibility and treated with MTZ were more likely to experience treatment failure compared with patients with susceptible isolates (OR = 6.8; 95% CI:1.96–23.8; P = 0.003). In patients given non-MTZ-based therapies, reduced susceptibility to MTZ was not predictive of failure to other treatments.

Conclusion
This is the first report to demonstrate that increased clinical failure rates for MTZ monotherapy are associated with reduced susceptibility to MTZ.

Disclosures
K. Garey, Summit Therapeutics: Collaborator, Research support.
714. Predictors of Influenza-Associated Hospitalization and Pneumonia in a Pediatric Population in Bangkok, Thailand
Authors: Sawani Ali , Suwanpakdee Detchvijitr , Watanaveeradej Veerachai , Weg Alden , Ellison Damon , Klungthong Chonticha , Phonpakobsin Thipwipha , Kerdpanich Phirangkul , Phiboonbanakit Danabhand , Gibbons Robert , Fernandez Stefan , Macareo Louis , Yoon In Kyu , Jarman Rick , Simasthien Sriluck , Anderson Kathryn 
Published: November 2018

Abstract

Background
Influenza infection in children can be severe, resulting in complications such as pneumonia, but may be mitigated by early recognition and administration of antivirals. In this study, we identified risk factors for hospitalization and pneumonia in a pediatric population presenting with influenza-like illness (ILI) in Thailand.

Methods
Our study included pediatric patients (age &lt; 18 years) presenting with ILI to inpatient and outpatient departments at a public hospital in Bangkok, Thailand, from 2009 to 2016. ILI was defined as fever plus cough or sore-throat, and pneumonia was defined as either lung radiographic or pulmonary examination abnormalities. Demographic and clinical data, as well as nasal and throat swabs, were collected during a one-time interview with patients presenting with ILI. Influenza infections were confirmed via RT-PCR testing of respiratory specimens. Retrospective chart review was used to collect data on individuals with influenza admitted for inpatient care.

Results
5,968 children (33.6%) were enrolled with ILI, of whom 1,530 (25.6%) were confirmed to be influenza by RT-PCR, of which 25.5% were influenza A(H1N1)pdm09, 31.5% influenza A(H3N2), and 43.0% influenza B. 124 (8.1%) patients were admitted, and 41 of these children (33.1%) developed pneumonia. Predictors of hospitalization included younger age (4.1 yrs for inpatients vs. 5.6 yrs) and higher presenting temperature (38.6C for inpatient vs. 38.0C) (both P &lt; 0.05). Among children hospitalized with influenza, influenza subtype was not associated with pneumonia risk. Co-detection of Klebsiella pneumoniae was associated with an increased risk of pneumonia (P &lt; 0.05. Patients with pneumonia were younger (4.1 yrs with vs. 6.4 yrs, P = NS), had a longer interval from fever onset to presentation at the hospital, and required longer hospital stays. Risk of pneumonia was decreased in patients who received oseltamivir within 48 hours of fever onset (odds ratio 0.36, 95% confidence interval 0.16–0.91).

Conclusion
Post viral pneumonia is a potentially serious complication of influenza, requiring longer hospitalization stay and affecting more than one-third of hospitalized pediatric patients with influenza. The risk of pneumonia can be reduced with early presentation for clinical care and prompt administration of oseltamivir following fever onset.

Disclosures
All authors: No reported disclosures.
715. Increase in Reported Respiratory Syncytial Virus Cases Among Adults in the Minneapolis-St. Paul Metropolitan Area, 2014–2018
Authors: Como-Sabetti Kathryn , Bye Erica , Strain Anna , McMahon Melissa , Lynfield Ruth 
Published: November 2018

Abstract

Background
Respiratory syncytial virus (RSV) is a common cause of respiratory infection, typically causing severe disease in young children. We were interested in evaluating trends of severe RSV infections in adults.

Methods
The Minnesota Department of Health conducts active surveillance for laboratory-confirmed RSV in hospitalized patients in the Minneapolis-St. Paul metropolitan area as part of the CDC Emerging Infections Program. Adults (≥18 years) cases identified during the RSV season (10/1–4/30) from 2014 through 2018 were analyzed and surveys of catchment-area hospital laboratories were conducted regarding respiratory virus panel (RVP) testing.

Results
Twenty-three catchment area hospitals serve adults. Four hospitals offered RVP during the 2014–2015 and 2015–2016 seasons; eight offered RVP during the 2016–2017 and 2017–2018 seasons. Three hundred and fifty-five cases were identified. Three hundred and nine (87%) were reported from four hospitals where RVP was offered throughout the study period. Case increases were observed at three hospitals; all of these hospitals offered RVP throughout the surveillance period; increases were not observed at hospitals where RVP was added for the 2016–2017 and 2017–2018 seasons. Cases increased from 42 in 2014–2015 to 198 in 2017–2018 (χ2 = 125.51, P &lt; 0.01), the proportion of cases reported by year was 12%, 15%, 17% and 56% during consecutive seasons. Cases by age groups over time generally did not differ; however, cases ≥85 years increased from 7% of total cases in 2014–2015 to 19% in 2017–2018 (χ2 = 6.14, P = 0.01). Overall, 23% of cases were admitted to the ICU and 7% died during hospitalization. The proportion of ICU admissions and deaths did not change over time.

Conclusion
We found an increase in adult RSV hospitalizations from 2014 to 2018, especially among the oldest age group. This increase was observed only at hospitals where RVP testing was offered throughout the surveillance period. It is unclear if this represents a true increase in RSV or a change in testing practices. However, it does illustrate that RSV should be considered as a cause of severe respiratory illness (SARI) in adults, particularly among the elderly. A more systematic approach in identifying the causes of SARI in adults would be informative, particularly as RSV vaccines and antivirals approach licensure.

Disclosures
All authors: No reported disclosures.
718. Viral Coinfection and Nasal Cytokines in Children with Acute Bacterial Sinusitis (ABS)
Authors: Lopez Santiago , Martin Judith M , Johnson Monika , Williams John V , Shaikh Nader 
Published: November 2018

Abstract

Background
ABS is one of the most common infections in childhood leading to antibiotic prescriptions, but remains a clinical diagnosis. Laboratory testing does not aid diagnosis and there are no predictors to identify those who will respond to therapy or develop complications. Thus, the tools to diagnose and manage ABS remain limited. Initial viral infection predisposes to development of ABS. However, there is poor understanding of the contribution of viral infection to pathogenesis, rate of complications, or the immune response to ABS. The objective of this study was to define bacterial upper airway colonization, viral co-infection and cytokine response in the upper airway during ABS.

Methods
In the context of an ongoing larger prospective clinical study, children were enrolled who were diagnosed with ABS using standardized clinical criteria. Nasopharyngeal (NP) samples were processed for bacterial culture for S. pneumoniae, H. influenzae, S. pyogenes and M. catarrhalis; real-time PCR viral testing and cytokine measurement by qPCR. We correlated these findings with clinical symptoms at the time of presentation.

Results
Of 184 enrolled children (median age 4.9 years), 134 (72.8%) had a positive bacterial culture for potentially pathogenic bacteria and 50 (27.2%) had growth of normal flora. A total of 129 (70.4%) subjects tested positive for a virus. The most common virus detected was rhinovirus (n = 86) followed by influenza virus (n = 23) and adenovirus (n = 21). A total of 102 patients (70.4%) had both a positive pathogenic bacterial culture and viral detection. Patients who had a bacterial pathogen plus a viral detection had a significantly higher expression of IL-6, IL-8 and IL-25 (P &lt; 0.001). Univariable analysis found no correlation between clinical presentation with viral and/or cytokine expressions.

Conclusion
Children meeting clinical criteria for ABS and a NP swab with a pathogenic bacteria plus viral detection demonstrated higher expression of inflammatory cytokines compared with subjects whose culture had normal respiratory flora.

Disclosures
J. V. Williams, Quidel: Board Member, Consulting fee. GlaxoSmithKline: Consultant, Consulting fee.
723. Validation of a Wild-Type Influenza A/Texas-Like H3N2 Human Challenge Model with Comparison to the Validated A(H1N1)pdm09 Model
Authors: Han Alison , Czajkowski Lindsay , Donaldson Amanda , Baus Holly Ann , Reed Susan , Athota Rani , Bristol Tyler , Rosas Luz Angela , Cervantes-Medina Adriana , Taubenberger Jeffery K , Memoli Matthew J 
Published: November 2018

Abstract

Background
Healthy volunteer challenge studies provide an opportunity to better understand influenza pathogenesis and correlates of protection. The development of vaccines and therapeutics has relied on these studies as will future universal vaccine candidates. The first fully validated wild-type human infection model with A(H1N1)pdm09 was developed at the NIH Clinical Center (CC) in 2012 and this study represents the first validation of a wild-type seasonal H3N2 human infection model. The objective of this study was to characterize a wild-type Influenza A/Texas-like H3N2 challenge virus in healthy volunteers.

Methods
Healthy volunteers were isolated at the NIH CC for a minimum of 9 days. Subjects received a single dose of a reverse genetics, cell-based, GMP, wild-type A H3N2 virus intranasally. Dose escalation was performed from 104 to 107 TCID50. Viral shedding and clinical disease were evaluated daily, including clinician assessments and a validated patient-reported outcome tool, FLU-PRO©.

Results
A total of 37 subjects were challenged. Sixteen (43%) subjects had viral shedding and 27 (73%) developed influenza symptoms, with 12 subjects (32%) experiencing mild-to-moderate influenza disease (MMID) defined as symptoms and shedding. Only subjects receiving the 106 and 107 TCID50 doses experienced MMID at 44% and 40%, respectively. Nose and throat symptoms were most common and peaked by Days 2–3 post-challenge. Although serum antibody responses were observed, many of these responses were limited in a significant number of subjects.

Conclusion
The A/Texas-like H3N2 Influenza challenge virus safely induced MMID in healthy volunteers, but was less effective than the A(H1N1)pdm09 challenge virus. This lower MMID rate of 40% was observed at the 107 TCID50 dose and was driven by less detection of shedding as the incidence of symptoms was similar to A(H1N1)pdm09. The limited serum antibody responses observed demonstrate that preexisting immunity in healthy volunteers against the seasonal H3N2 lineage may limit shedding compared with the more recently emerged seasonal A(H1N1)pdm09 lineage. The successful characterization of this H3N2 model makes future studies using this model to explore viral pathogenesis or evaluate vaccines possible.
This research was supported by the Intramural Research Program of the NIH, NIAID.

Disclosures
All authors: No reported disclosures.
724. Neurologic Complications in Hospitalized Pediatric Patients with Influenza Infection, A Multicenter Retrospective Study in Korea
Authors: Choi Gwang-Jun , Park Ji Young , Choi Joon-Sik , Kim Bitna , Choi Sae Rom , Kim Dong Sub , Kang Ji-Man , Lee Jun Wha , Woo Young-Jong , Lee Jeehun , Kim Yae-Jean 
Published: November 2018

Abstract

Background
The aim of the study was to evaluate the incidence and characteristics of influenza associated neurologic complications (IANCs) in hospitalized pediatric patients in Korea.

Methods
We performed retrospective review of hospitalized cases of confirmed influenza infection from October 2010 to April 2017. Patient’s data were collected from three referral hospitals in different regions of the country.

Results
A total 2,002 laboratory confirmed influenza cases were identified. The median age was 3.3 years old (range 0.0–18.9 years) and 1,003 patients were male (54%). Influenza A was diagnosed in 1,357 cases (68%), influenza B in 624 (31%) and both influenza A and B in 21 (1%). Other combined respiratory virus infection was detected in 104 (5.2%) cases. Out of 2,002 cases, IANCs were identified in 167 cases (8.3%); influenza virus A was detected in 116 (69.4%), B in 50 (29.9%) and both A and B in one case (0.6%). Of 167 cases with IANCs, 25 patients (15%) had underlying neurologic diseases. Eleven patients (11/167, 6.5%) had combined respiratory viral infection (Rhinovirus = 5; respiratory syncytial virus = 3; coronavirus = 2; and bocavirus = 1). The most common diagnosis was a simple febrile seizure (112/167, 67.1%), followed by other seizures (26/167, 15.6%), encephalopathy/encephalitis (17/167, 10.2%), meningitis (7/167, 4.2%), meningism (4/167, 2.4%) and acute ataxia (1/167, 0.6%). In two patients with encephalitis/meningitis, one patient had influenza A and the other patient had influenza B detected by PCR in cerebrospinal fluid. Most of the patients were fully recovered (162/167, 97%) and no neurologic complication occurred in patients who had only initial manifestation of simple febrile seizure. Ten patients (10/167, 6.0%) required hospitalization in intensive care unit. Three patients (3/167, 1.8%) died of encephalopathy (n = 1) and combined encephalopathy/myocarditis (n = 2). Pre-existing neurologic disease was a risk factor of IANCs with an odds ratio of 3.94 (95% confidence interval 2.37 to 6.56, P &lt; 0.0001).

Conclusion
IANCs is not rare and may cause serious outcome including death. Clinicians should be aware of the increased risk for IANCs in certain patients with neurologic diseases.

Disclosures
All authors: No reported disclosures.
730. Hospital Readmissions Following Laboratory-Confirmed Influenza
Authors: Dobrzynski David , Ndi Danielle , Markus Tiffanie , Zhu Yuwei , Schaffner William , Talbot H Keipp 
Published: November 2018

Abstract

Background
Further understanding of hospital readmissions after influenza illness could reduce readmissions. The aim of our study was to characterize the morbidity associated with laboratory confirmed influenza hospitalizations.

Methods
This was a retrospective study using data from 2006 to 2016 from the Tennessee (TN) Emerging Infections Program Influenza Surveillance Network, which prospectively identifies laboratory-confirmed influenza hospitalizations in Nashville, TN and surrounding counties. Using the TN Hospital Discharge Data System, which collects information on all hospitalizations and discharges in TN, cases were linked to subsequent hospitalizations up to 1 year. The International Classification of Diseases was used to define the primary diagnosis associated with each hospitalization. Demographic characteristics and outcomes were compared by using χ2 tests for categorical variables. Multivariable logistic regression was used to compare study outcomes.

Results
Of the 2,897 patients with a laboratory-confirmed influenza hospitalization, 1,364 (47%) had a hospital readmission during the subsequent year (figure). Multiple readmissions occurred in 740 patients (54%). The readmission group was older, female predominant, and had more comorbidities than patients not re-hospitalized. Acute COPD/asthma exacerbation, pneumonia, septicemia, and acute renal failure were the most common causes for readmission. Underlying cardiovascular disease (OR 1.6), lung disease (OR 1.6), kidney disease (OR 1.7), diabetes (OR 1.3), immunosuppression (OR 1.6), and liver disease (OR 2.1) were associated with increased risk of readmission (table).

Conclusion
An influenza hospitalization is associated with increased hospital readmissions. Approximately 47% of patients hospitalized with influenza are readmitted within 1 year. Patient comorbidities could be an important link to influenza readmissions.

Disclosures
W. Schaffner, Merck: Member, Data Safety Monitoring Board, Consulting fee. Pfizer: Member, Data Safety Monitoring Board, Consulting fee. Dynavax: Consultant, Consulting fee. Seqirus: Consultant, Consulting fee. SutroVax: Consultant, Consulting fee. Shionogi: Consultant, Consulting fee. H. K. Talbot, sanofi pasteur: Investigator, Research grant. Gilead: Investigator, Research grant. MedImmune: Investigator, Research grant. Vaxinnate: Safety Board, none. Seqirus: Safety Board, none.