bluuebunny/crossref_metadata_2025_split huggingface dataset:
496. Carbapenem-resistant Enterobacter: A Case-Case–Control Investigation
Authors: Cohen Mendel Leore , Katz David , Lazarovitch Tsilia , Zaidenstein Ronit , Marchaim Dror 
Published: October 2019

Abstract

Background. Background
The World Health Organization has declared carbapenem-resistant Enterobacteriaceae (CRE) as a worldwide public health threat. Analyzing the epidemiology of CRE was derived from cohorts consisting primarily of Klebsiella pneumoniae isolates. The second most frequent CRE is Enterobacter (CREn), but its molecular and clinical epidemiology differ from that of K. pneumoniae, and it has not been analyzed while implementing updated methodological tools and design.

Methods
A matched case-case–control investigation was conducted at Shamir (Assaf Harofeh) Medical Center, Israel, for calendar years 2007–2017. Each CREn case was matched to a carbapenem-susceptible Enterobacter (CSEn) case and to an uninfected control (1:1:1 ratio). Logistic and Cox regression-matched analyses were conducted in order to study predictors and outcomes of CREn colonization and/or infection, respectively.

Results
The study included 216 cases (72 in each group). Numerous predictors were significantly associated with CREn as per bivariable analyses, but the only independent significant predictors were: (1) recent (3 months) exposure to fluoroquinolones (aOR=2.94, P = 0.04), (2) intensive care unit stay in current hospitalization prior to culture (aOR=3.56, P = 0.003), and (3) a rapidly fatal McCabe score (aOR=0.471, P = 0.01). Patients with CREn suffered from significant delays in instituting appropriate antimicrobials (P = 0.03), and for those who survived the hospitalization, were more frequently discharged to a long-term care facility after being admitted to the index hospitalization from home (aOR=3.3, P = 0.02).

Conclusion
This case-case–control-matched investigation of CREn epidemiology, revealed a unique modifiable predictor, i.e., recent fluoroquinolone exposure, which could represent a target for stewardship intervention. The case-case–control-matched design allowed for the control of numerous confounders previously reported to be associated with CREn but may represent a risk factor for Enterobacter infection in general. As with other CRE, CREn carriers suffer from significant delays in initiation of appropriate antimicrobials and from worse outcomes.

Disclosures
All authors: No reported disclosures.
500. Prevalence of Extended-Spectrum β-lactamase and Carbapenem-Resistant Gram-Negative Bacteria in Patients with Urinary Tract Infection and Urosepsis Admitted through Emergency Departments in the United States
Authors: Takhar Sukhjit , Krishnadasan Anusha , Moran Gregory J , Mower William , Pathmarajah Kavitha , Gonzalez Eva , Vargas Julia , Talan David A 
Published: October 2019

Abstract

Background
Gram-negative infections due to extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, and carbapenem-resistant Enterobacteriaceae (CRE) and non-fermenting (CR-NF) strains, are increasingly encountered. Study objectives were to determine prevalence and associated risk factors and outcomes for these strains among emergency department patients hospitalized for urinary tract infection (UTI) at 11 US hospitals.

Methods
This was a prospective observational study of patients ≥18 years hospitalized for UTI. Clinical data were collected at the index visit. Urine was obtained for culture and susceptibility testing. Electronic medical record and telephone follow-up were conducted after 30 days for site laboratory results, treatment, and clinical outcomes. Positive culture was defined as 1 uropathogen with growth at ≥104 cfu/mL, or 2 with 1 or both at ≥105 cfu/mL, or ≥3 with 1 or 2 at ≥105 cfu/mL. Isolates with ceftriaxone (CRO) or meropenem MIC >1 μg/mL will undergo reference laboratory (IHMA, Inc., Schaumburg, IL) susceptibility testing, including against newer antibiotics and cefiderocol.

Results
We enrolled 774 participants between 2018 and 2019; 289 (37.3%) excluded due to urine culture not done, no growth, or contamination. Of 485 culture-positive participants (median age 56 years, 62.0% female), 432 (89.1%) grew 1 uropathogen, 48 (9.9%) 2, and 5 (1.0%) ≥3. Prevalences of CRO-resistant Enterobacteriaceae, CRE, and CR-NF were 19.9%, 2.1%, and 10.7%, respectively. At sites, 95.7% of CRO-resistant Enterobacteriaceae isolates were ESBL. Among participants with any or no antibiotic resistance risk factors, i.e., antibiotics, hospitalization, long-term care, or travel within 90 days, prevalence of CRO-resistant Enterobacteriaceae was 68/228 (29.8%) and 10/155 (6.5%), respectively. Among those with CRO-resistant vs. susceptible Enterobacteriaceae infections, ICU admission and death occurred in 9.9% vs. 6.6% and 3.7% vs. 1.0%, with median time home over 30 days, 24 vs. 27 days, respectively.

Conclusion
Among US hospitalized patients with UTI, infections due to CRE remain uncommon; however, ESBL and CR-NF now account for a substantial proportion of cases and are associated with resistance risk factors and worse outcomes.

Disclosures
All authors: No reported disclosures.
511. MDRO Carriage in Patients in Two ICUs and Prevalence of Environmental Surface and Healthcare Worker Hand Contamination
Authors: Tanner Windy , Coombs Jana , Fernley Tasha , Danala Suresh , Lopansri Bert K , Rubin Michael 
Published: October 2019

Abstract

Background
Determining MDRO (multidrug-resistant organism) transmission routes in intensive care units (ICUs) can be complex and require the evaluation of multiple potential MDRO sources, including patients, the environment, and healthcare worker (HCW) hands. The objective of this study was to determine MDRO carriage in patients in two separate ICUs, and simultaneous environmental and HCW hand contamination from associated rooms.

Methods
Patient (P), environmental (E), and HCW hand (H) samples were collected from hospital A (1183 H, 1253 E, 729 P) and hospital B (699 H, 1372 E, 437 P) over approximately 5 weeks in each unit. Environmental and HCW hand samples were collected using a cellulose sponge. HCW hand samples were collected prior to any hand hygiene. Patient samples were collected from the axilla, groin, and perianal areas with a flocked swab with patient consent. All samples were tested semi-quantitatively for Clostridium difficile (Cdiff), vancomycin-resistant enterococci (VRE), and cefotaxime-resistant Enterobacteriaceae (Cef-R-Ent) by selective culture. Cdiff isolates representative of each P/E/H cluster were tested for Cdiff toxin testing by PCR.

Results
Cdiff, VRE, and Cef-R-Ent were detected in patients, patient rooms, and on HCW hands in both facilities (Table 1). Cdiff was more prevalent in Facility A, while Cef-R-Ent was more prevalent in Facility B. The prevalence of VRE was minimal in both facilities. Cdiff toxin gene testing revealed that 17% of the Cdiff isolate clusters tested positive for toxin genes. In Facility A, the prevalence of a given MDRO was similar regardless of sample type, but was more widely varied between sample types in Facility B. Prevalence of MDROs on HCW hands and in the environment was typically higher in Facility A compared with Facility B. Individual patient positives were frequently linked to positive HCW hand and environmental cultures.

Conclusion
We discovered a low prevalence of all MDROs in both facilities, with most positive cultures associated with patients who were not on MDRO precautions. HCW hand and environmental MDRO prevalence was generally similar for each MDRO, regardless of patient prevalence, supporting previously reported links on HCW hand contamination and hospital room surfaces.

Disclosures
All authors: No reported disclosures.
532. Can Saccharomyces boulardii Therapy Be Effective in Decolonizing Rectal Carbapenem-Resistant Enterobacteriaceae (CRE) Colonization?
Authors: Resat Sipahi Oguz , Quliyeva Gunel , Cilli Feriha , Deniz Kucukler Nilgun , Dikis Demet , Bilgili-Korkmaz Nilay , Barik-Aksit Sukran , Kepeli Nurhayat , Arda Bilgin , Ulusoy Sercan 
Published: October 2019

Abstract

Background
CRE are globally important pathogens associated with significant morbidity and mortality. The problem of carrying CRE may continue to create a problem in discharged cases in the community. Saccharomyces boulardii sachet therapy (SBST) is reported to cause decolonization in several MDR bacteria carriers. Herein, it is aimed to present the decolonizing rates of rectal CRE colonized cases after SBST treatment.

Methods
The study period was August 2018–March 2019. Inclusion criteria were: (i) age >18, (ii) receiving Saccharomyces boulardii 250 mg sachets q12h for 7 days, (iii) being proven CRE carrier on rectal swab culture (RSC) up to 5 days period before SBST. The first repeated RSC was performed 3–5 days after the end of SBST. Data were retrieved from the hospital electronic database. Cases with three consecutive weekly performed negative RSC were considered to be decolonized. RSC were processed according to CDC protocol; briefly, the swab was inoculated into 10 mL of trypticase soy broth (bioMérieux Inc., Marcy-l’Étoile, France) with the addition of one 10-μg ertapenem disk (Oxoid, Altrincham, UK) and incubated at 35°C for 18–20 h. The next day, after vortexing, 100 μL of the inoculum was subcultured (8) onto chromID CARBA agar plates (bioMérieux) and incubated at 35°C for 18–20 h. Suspected CRE colonies on chromID CARBA (blue/green to blue/gray in color) were identified by the VITEK MS system (bioMérieux). Susceptibility testing of the isolates was performed with the VITEK 2 system (bioMérieux). Isolates were tested for their resistance phenotypes to imipenem, ertapenem, and meropenem by E-test (bioMérieux). The results were interpreted according to the EUCAST criteria.

Results
Fifteen cases [2 women, mean age 60.6 ± 18.3 (min. 18–max. 83)] fulfilled the inclusion criteria. All had a history of carbapenem usage. Five cases (33%) had three consequent negative RSC after SBST and were considered to be decolonized. Twelve cases were receiving concomitant antibiotic during SBST (10 carbapenem based regimens). Three cases who received no concomitant antibiotic were decolonized.

Conclusion
SBST may be a promising tool for decolonizing CRE carriers. These data need to be validated in larger cohorts preferably via randomized-controlled trials.

Disclosures
All authors: No reported disclosures.
533. Impact of Different Definitions on Reported Rates of Carbapenem-Resistant Enterobacteriaceae (CRE)
Authors: Passaretti Catherine , Neelakanta Anupama , Layell Jessica , Campbell Eileen , Kester Shelley 
Published: October 2019

Abstract

Background
Different definitions exist for tracking and trending rates of hospital-acquired Carbapenem-resistant Enterobacteriaceae (CRE). National Health Safety Network (NHSN) allows for Laboratory Identified Event (LabID) and Healthcare-associated infection (HAI) surveillance reporting for CRE. Our facility developed an internal definition for CRE prior to release of the NHSN modules that differs from the CDC definitions in that patients colonized or infected with CRE identified on hospital day 1 or 2 who had a hospitalization within the past four weeks are considered community-onset healthcare facility acquired (COHCFA) and are included in our HA definition. In addition, by our definition once a patient develops CRE any subsequent positive cultures for the same organism are not considered new events.

Methods
All CRE cultures at our facility were reviewed by an infection preventionist and hospital epidemiologist who categorized each culture as hospital acquired by our internal HA definition, NHSN LabID definition and NHSN HAI definition. Results from each method of surveillance were compiled and compared as were trends of HA CRE over time by each definition.

Results
590 patients with 975 clinical cultures for Carbapenem-resistant Klebsiella spp., Enterobacter spp and E. coli were reviewed from January 2012 to March 2019. 297 cultures met our internal definition for HA CRE compared with 302 by NHSN LabID and 189 by NHSN HAI surveillance. Sixty-one (21%) of HA cases by our definition were COHCFA. 259 patients had multiple CRE cultures and 1 patient had 22 cultures with the same CRE organism between 2014 and 2019 and met for 5 lab ID events and 5 NHSN HAI events. All 3 tests agreed that a culture was HA in 140 instances (14%) and all 3 agreed that a culture was not HA in 589 instances (60%). At least one definition yielded a discordant result in 246 cultures (25%). Trends over time were compared between the definitions. While the number of HA cases varied based on the definition used, overall trends over time were similar regardless of the definition utilized. (Figure 2)

Conclusion
Regardless of the definition used for surveillance of CRE, trends over time are similar. Consideration should be given to monitoring COHCFA cases in addition to those acquired on or after hospital day 3.

Disclosures
All authors: No reported disclosures.
582. Impact of Central Line Bundle for Prevention of Umbilical Vein Catheter-Related Bloodstream Infections in a Neonatal Intensive Care Unit
Authors: devrim İlker , Kulalı Ferit , Çağlar İlknur , Oruc Yeliz , Demiray Nevbahar , Dursun Vecihe , Gulfidan Gamze , Bayram Nuri , çalkavur şebnem 
Published: October 2019

Abstract

Background
Umbilical vein catheters (UVC) are one of the most common types of vascular access device in the neonatal intensive care units. Central line-associated bloodstream infections were reported to be in the first place of healthcare-associated infections in preterm infants. In this study, we aimed to evaluate the effectiveness of the bundle applications in the prevention of umbilical vein catheter-associated bloodstream infections in neonates including premature infants.

Methods
This 40 months cross-sectional study included two periods, including pre-bundle period (from August 1, 2015 to March 31, 2017) and bundle period (April 1, 2017 to November 30, 2018). The umbilical vein catheter-related bloodstream infections, catheter line days, number of the patients were recorded and compared between the prebundle and bundle periods. Bundle steps were defined as education-training-assignment, evaluation of daily catheter indications, hand hygiene and aseptic technique while insertion, maximal sterile barrier precautions, closure of the catheter area with transparent semi-permeable membrane, using needless connectors in stead of 3-way stop-cocks, and single-use prefilled saline syringes for flushing.

Results
During the whole study period total umbilical vein catheter days were 2,228 days. During the prebundle period there was 10 and in the bundle period there was 2 umbilical vein catheter-related bloodstream infections (Table 1). While umbilical vein-associated bloodstream infection rate was 8.9 per 1,000 catheter days in the pre-bundle period, and significantly decreased to 1.79 in the bundle period (P < 0.05). After the introduction of bundle applications, it was observed that the rate of infection decreased by 68% (P < 0.05)

Conclusion
Our study showed that implementation of central line bundle including needless connectors and single-use prefilled syringes for umbilical vein-related bloodstream infections was effective for the prevention of catheter-related bloodstream infections in neonatal intensive care units.

Disclosures
All authors: No reported disclosures.
600. β-Lactam Resistance Mechanisms in Pseudomonas aeruginosa Isolates Analyzed Using Whole-Genome Sequencing (WGS) and Transcriptions Analysis and Their Impact in Resistance to New β-Lactam/β-Lactamase Inhibitors
Authors: Castanheira Mariana , Doyle Timothy B , Hubler Cory , Healy Matthew , Smith Caitlin J , Mendes Rodrigo E 
Published: October 2019

Abstract

Background
Ceftazidime–avibactam (CAZ-AVI) and ceftolozane-tazobactam (C-T) display excellent antipseudomonal activity, but Pseudomonas aeruginosa (PSA) susceptibility against these agents can be affected by acquired resistance genes and mutations. We evaluated resistance mechanisms against these agents among 109 PSA isolates using WGS and messenger (m)RNA-sequencing.

Methods
PSA clinical isolates from Europe (n = 62), Asia-Pacific (n = 22), and Latin America (n = 25) in 2017 were susceptibility tested using reference methods and 109 were randomly selected for WGS and total mRNA-sequencing. Data were analyzed using custom software and logistic regression.

Results
Isolates carrying metallo-β-lactamases (MBLs) (n = 24) were resistant to all β-lactams, including CAZ-AVI and C-T. The only compound inhibiting >50% of the isolates was colistin. ESBL genes (blaVEB-1 or blaVEB-9), some oxacillinases, and PDC variants caused resistance to CAZ-AVI and C-T, but the presence of blaPER-1, blaGES-6, and PDC-97 led to resistance to C-T, but not to CAZ-AVI. Disruptions of ampR (PDC regulator) and glnD (nitrogen metabolism) were associated with resistance to CAZ-AVI and C-T, but armZ (anti-repressor of mexZ) disruption was only associated with C-T resistance. The combination of wild-type sequences of various genes was negatively associated with resistance to CAZ-AVI and C-T, but alterations in dnaJ (chaperone) and oprM were only related to C-T resistance. mRNA-sequencing data did not show strong correlations with CAZ-AVI or C-T resistance or with expression of genes involved in β-lactam resistance, but further analyses will expand the genes analyzed. Interestingly, among 14 isolates overexpressing MexAB-OprM that extrude CAZ, only 6 had CAZ-AVI MICs >8 mg/L.

Conclusion
Resistance mechanisms against CAZ-AVI and C-T remain poorly understood beyond MBL acquisition. In this study, resistance mechanisms statistically associated with CAZ-AVI resistance in PSA were noted among C-T-resistant isolates, but some mechanisms were only observed among C-T-resistant isolates. The richness of results employing these 2 methodologies requires further investigations that are being performed to evaluate sequences and expression alterations.

Disclosures
All authors: No reported disclosures.
624. Molecular Characterization of Baseline Enterobacteriaceae and Pseudomonas aeruginosa from a Phase 3 Nosocomial Pneumonia (ASPECT-NP) Clinical Trial
Authors: Castanheira Mariana , Johnson Matthew G , Yu Brian , Huntington Jennifer A , Carmelitano Patricia , Bruno Christopher , Rhee Elizabeth G , Motyl Mary 
Published: October 2019

Abstract

Background
ASPECT-NP, a phase 3, randomized, double-blind, multicenter trial, evaluated ceftolozane/tazobactam (C/T) 3 g q8h vs. meropenem 1 g q8h for 8–14 days in adults for treatment of ventilated nosocomial pneumonia. Baseline Gram-negative (GN) isolates from patients were tested for mechanisms of resistance.

Methods
Lower respiratory tract (LRT) isolates were sent to a central laboratory for organism identification and susceptibility. Of 664 total Enterobacteriaceae (ENT) and Pseudomonas aeruginosa (PsA) isolates, 351 (53%) were nonsusceptible to broad-spectrum cephalosporins and/or carbapenems and underwent whole-genome sequencing, quantitative RT–PCR, and western blot analysis. ENT isolates were tested for the presence of acquired β-lactamase genes and AmpC levels (selected species). PsA isolates were tested for acquired β-lactamase genes, AmpC (PDC) levels, efflux pump expression, and OprD loss.

Results
Of 262 ENT isolates, 114 (44%) were susceptible to C/T (MIC ≤2 µg/mL). An extended-spectrum β-lactamase (ESBL) gene was carried by 89 (78%) of the C/T-susceptible isolates. Of 148 C/T-nonsusceptible (C/T-NS) isolates, 87 (59%) were carbapenemase negative, and the majority 135 (91%) also carried an ESBL gene. The most common ESBL was blaCTX-M15 with blaOXA-1 and blaOXA-30. Klebsiella pneumoniae often displayed higher C/T MICs compared with other species carrying the same resistance genes. Among all C/T-NS isolates, 61 (41%) were carbapenemase positive, most commonly K. pneumoniae carrying blaOXA-48, blaNDM-1, and blaNDM-5. Of 89 PsA isolates, 58 (65%) were susceptible to C/T (MIC ≤4 µg/mL), despite elevated AmpC expression, efflux pumps, or loss of OprD; only 5 isolates had an acquired β-lactamase. Of the 31 C/T-NS PsA isolates, only 12 (39%) were carbapenemase positive and carried blaVIM or blaGES; isolates carrying blaGES had lower C/T MICs (8–32 µg/mL) compared with blaVIM (MIC > 128 µg/mL). PDC alleles were similar in isolates with high and low C/T MICs.

Conclusion
In baseline GN LRT isolates from ASPECT-NP, the most common ESBL detected in ENT was blaCTX-M15; carbapenemases were uncommon. There was no correlation of ESBL phenotype to C/T susceptibility among ENT, nor of PDC allele to C/T susceptibility among PsA.

Disclosures
All authors: No reported disclosures.
643. Comparison of Multiplex Polymerase Chain Reaction (PCR) and Routine Culture for the Detection of Respiratory Pathogens in Pneumonia Patients
Authors: Abu Sitta Emad , Hubbard Nicole , Suleyman Geehan 
Published: October 2019

Abstract

Background
The identification of causative pathogens in pneumonia can be challenging, and conventional culture methods can take up to 72 hours. However, rapid microbiologic tests identify organisms within hours. The Biofire®Filmarray ((bioMérieux, North Carolina) Pneumonia Panel was recently approved by the FDA. The multiplex PCR system identifies 33 targets from sputum and bronchoalveolar (BAL) samples, which include 18 bacteria, 8 viruses, and 7 antibiotic resistance genes. The purpose is to compare the panel to routine culture methods for the detection of respiratory pathogens in patients with pneumonia in a 794-bed teaching hospital in northwest Ohio.

Methods
We retrospectively screened all hospitalized intensive care unit patients who met clinical and radiological criteria of pneumonia using electronic medical records between November 2018 and February 2019. Adult patients who had respiratory cultures collected within 7 days were included. Repeat specimens were excluded. Routine cultures were performed using the laboratory’s standard procedure, and Pneumonia Panel testing was performed according to manufacturer instructions.

Results
Fifty-nine respiratory or 13 BAL and 46 sputum specimens were evaluated. There was no discrepancy between culture and PCR in 63% (37/59) samples. One (8%) BAL and 10 (22%) sputum specimens had additional pathogens detected by PCR. There was a discrepancy between culture and PCR in four (31%) BAL and seven (15%) sputum samples. The largest discrepancy was noted amongst Serratia marcescens (4/59 or 7%) and Haemophilus influenzae (6/59 or 10%) species. Only one sputum culture had Legionella detected by PCR. Additionally, 17 specimens had a virus detected either alone or with another bacterial pathogen by PCR. For the resistance genes, KPC was detected by PCR but not by Modified Carbapenem Inactivation Method (mCIM) test. The mecA gene was detected in six of seven (86%) of methicillin-resistant Staphylococcus aureus (MRSA) isolates. CTX-M was detected in Serratia and Klebsiella pneunomiae in two samples; however, the organisms were not isolated in culture.

Conclusion
The Pneumonia Panel can identify additional bacteria that did not grow in culture. This panel can rapidly identify pathogens and potentially reduce unnecessary antibiotic use.

Disclosures
All authors: No reported disclosures