bluuebunny/crossref_metadata_2025_split huggingface dataset:
2171. Phenotypic Correlations for the Presence of CTX-M in Enterobacteriaceae and mecA in Staphylococcus aureus using the Verigene® Blood Culture System
Authors: Masayuki Nigo , Wanger Audrey , Arias Cesar A 
Published: October 2019

Abstract

Background
Rapid identification of antimicrobial resistance markers has the potential to help targeting antimicrobial therapy and enhance efforts for antibiotic stewardship. However, limited data are available to correlate phenotypic and genotypic results for some of these platforms in positive blood cultures (BC). Here, we aimed to evaluate the ability of the Verigene® (VG) Blood Culture System to predict phenotypic susceptibility patterns with the detection of the genes encoding the CTX-M in Enterobacteriaceae and MecA in S. aureus (SA) in a large dataset.

Methods
Phenotypic susceptibility and VG results were retrospectively collected between August 2017 and December 2018 from 12 hospitals in Houston, TX. VG testing was performed on only the first isolate was considered in persistent positive BCs. The VG report of the presence of blaCTX-M or mecA was correlated with phenotypic susceptibility to ceftriaxone (CTO) (E. coli [EC] and Klebsiella spp.[KL]) or oxacillin (SA), respectively.

Results
We identified a total of 5,937 VG results. The final analysis was performed on 2,356 cases where EC, KL or SA was identified. Isolates detected KPC and NDM by VG were excluded. 30 EC/KL were missed by VG in polymicrobial bacteremia. 7 polymicrobial positive BCs with coagulase-negative staphyloccocci were mislabeled as MecA positive MSSA. Among isolated detected by VG, there were the high sensitivity and specificity of CTX-M to identify CTO resistance (97.2% and 99.7% in EC and 91.4% and 99.2% in KL). For SA, the sensitivity and specificity of mecA were 100% and 99.6% to identify oxacillin resistance. 2 isolates with mecA positive by VG were reported as oxacillin-suscpetible.

Conclusion
Our results revealed that there is a high correlation between VG and phenotype. For SA, discrepancies between genotype and phenotype seem to be influenced by the presence of other organisms in the sample. Genotypic information seems reliable and should guide targeted therapy in bloodstream infections.

Disclosures
All authors: No reported disclosures.
2172. True Positivity of Common Blood Culture Contaminants among Pediatric Hospitalizations in the United States, 2009–2016
Authors: Spaulding Alicen B , Watson David , Dreyfus Jill , Heaton Phillip , Kharbanda Anupam 
Published: October 2019

Abstract

Background
Distinguishing blood culture (BC) results between common contaminants (CC) and truly pathogenic organisms can be challenging, especially among pediatric patients, but is important for effective clinical care. However, no recent studies have analyzed the true positivity of common BC contaminants in pediatric patients using linked laboratory data from a large national sample of United States hospitals.

Methods
We conducted a retrospective cohort study among patients ages < 19 using the Premier Healthcare Database (2009–2016), limiting to hospitals reporting ≥ 4 years of BC data and encounters with one of the five most frequent CC among laboratory-confirmed BC. True positivity was defined for each CC as a second positive BC within 48 hours among all BCs. A multivariable logistic regression model including all variables significant in univariate analyses was created comparing encounters: (1) with and without a second BC; and (2) second BC positive vs. negative, with corresponding adjusted odds ratios (aOR) and 95% confidence intervals (CI) reported.

Results
A total of 5056 isolates corresponding to 4915 encounters with a CC were included in this analysis; 3075 (61%) isolates had a second BC within 48 hours. Adjusted odds of a second BC were higher for encounters from urban (aOR: 1.73, 95% CI: 1.31, 2.29) and ≥ 500 bed hospitals (aOR 1.40, 95% CI: 1.20,1.63). True positivity was 20.2% for coagulase-negative staphylococci (CoNS), 5.9% for Bacillus spp., 5.2% for Viridans group streptococci, 5.0% for Diphtheroids spp., and 3.1% for Micrococcus spp. True positivity for CoNS was higher among neonates but all other organisms were higher for non-neonates (figure). Adjusted odds of true positivity were higher for encounters with chronic conditions (OR 1.44, 95% CI: 1.13, 1.82), a central line in place (OR: 1.65, 95% CI: 1.30, 2.10), per length of stay day (OR: 1.01 (1.01, 1.01), and with an intensive care unit admission (OR: 1.39, 95% CI: 1.08, 1.77).

Conclusion
True positivity varied substantially by organism, and in most cases was higher among non-neonates. Regional variations for conducting a second BC within 48 hours were found, and more seriously ill patient encounters were more likely to have a common contaminant be pathogenic.

Disclosures
All authors: No reported disclosures.
2177. The Impact of the BioFire® FilmArray® Gastrointestinal Syndromic Panel on the Management of Infectious Gastroenteritis due to Diarrheagenic E. coli Strains in a Large Community Hospital
Authors: Jackson Christoper Bryan , Astorga Brenda , Gawrys Gerard , Reveles Kelly R , Lee Grace 
Published: October 2019

Abstract

Background
PCR-based rapid diagnostic tests (RDTs) provide rapid and accurate infectious gastroenteritis (IGE) etiologies within hours. However, there are limited data evaluating the impact of these panels on the appropriate management for diarrheagenic E. coli strains (DECS). This study evaluated the impact of the BioFire® FilmArray® GI panel on the appropriate antimicrobial management of DECS.

Methods
A retrospective analysis was conducted at a large community hospital in San Antonio, TX. Patients with a positive infectious diarrhea diagnostic panel (IDDP) for DECS from October 1, 2016 through September 30, 2018 and admitted for ≥48 hours were included. Patients were excluded if they had a positive IDDP for multiple DECS. An algorithm based on all available literature was used to classify appropriate management of DECS, which included patients having prolonged diarrhea (≥7 days), immunocompromised hosts (ICHs), or the presence of systemic symptoms. Antimicrobial therapy changes based on IDDP results, presence of an ID consult, and incidence of hemolytic uremic syndrome (HUS) were evaluated.

Results
A total of 374 patients were included for analysis. Overall, the IDDP did not lead to a change of therapy in 290 cases. However, the IDDP resulted in 84 antimicrobial changes including initiation of appropriate antibiotics (n = 48) and de-escalation/discontinuation (n = 22), primarily in special populations, such as ICHs. The IDDP results led to appropriate therapy optimization in 63%, 17%, 16%, and 9% of enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), and enterotoxigenic E. coli (ETEC) cases, respectively. In contrast, 81% of Shiga toxin-producing E. coli (STEC) cases were inappropriately managed with antibiotics, and 33% developed HUS. Only 14% of all DECS cases generated an ID consult.

Conclusion
Of note, this study found that the IDDP did not lead to a change in the management of most pathotypes. However, it was associated with positive changes in the management of DECS in specific patients, particularly ICHs. RDTs assist providers in the timely identification and treatment of IGE pathogens, but both antimicrobial and diagnostic stewardship remain critical for the optimal management of DECS.

Disclosures
All authors: No reported disclosures.
2184. Effect of Adjusted CLSI Breakpoints on Center-wide Fluoroquinolone Susceptibilities for Enterobacteriaceae and Pseudomonas aeruginosa: Is It Time to Restrict Empiric Fluoroquinolone Use?
Authors: Sansom Sarah , Moore Nicholas M , Kazi Aamir S , Won Sarah Y 
Published: October 2019

Abstract

Background
In January 2019, the Clinical and Laboratory Standards Institute (CLSI) lowered breakpoints of fluoroquinolones (FQ) for Enterobacteriaceae (EB)and Pseudomonas aeruginosa (PsAr). Automated commercial antimicrobial susceptibility testing (cAST) can only report levofloxacin MIC ≤1 μg/mL according to 2018 breakpoints. Updated panels will not be available until FDA approval. Laboratories and antimicrobial stewardship programs (ASP) must decide how to implement the adoption of new FQ breakpoints.

Methods
All microbiologic isolates of EB or PsAr were collected March 11, 2019–March 22, 2019. Manual E-tests and cAST by Microscan were performed for levofloxacin. Susceptible or non-susceptible (NS) isolates to levofloxacin were identified using 2018 and 2019 CLSI breakpoints [Table1]. Data were analyzed by Microsoft Excel and SPSS.

Results
159 isolates were analyzed. Isolates were predominantly from urine (78%) and females (68%). E.coli was the most frequently identified organism (40%) [Figure 1]. Application of new breakpoints changed 7% of EB (P = 0.083) and 16% of PsAr (P = 0.238) from susceptible to NS. [Figure 2] PsAr had higher rates of FQ NS compared with EB with new breakpoints (37% vs. 22%, P = 0.132, not shown). Non-urine and inpatient isolates had decreased susceptibility of ≥10% (P = 0.168 and 0.117). Lack of other resistance mechanism (ESBL, CRE, MDRO) was associated with a change in susceptibility (P = 0.036). Diagnosis of active cancer or immunosuppression (IS) was strongly associated with FQ NS by new breakpoints (P = 0.019, not shown). Patients with cancer or IS had the largest decrease in susceptibility (18%, P = 0.069) with application of new breakpoints. [Table 2].

Conclusion
Updated CLSI FQ breakpoints resulted in trends of increased resistance. PsAr, non-urine and inpatient isolates were disproportionately affected. Implementation of manual MIC determination from select clinical isolates may be useful until approval of updated cAST. Diagnosis of cancer or IS was associated with FQ NS by new breakpoints. Restriction of FQ for empiric use may be considered, particularly in patients with cancer or IS. Larger studies are needed to determine the long-term effects of adjusted FQ breakpoints, but are anticipated to have significant impacts on ASP.

Disclosures
All authors: No reported disclosures.
2190. Influence of Microbiological Culture Results on Antibiotic Choice for Veterans with Hospital-Acquired Pneumonia
Authors: Lee Anne. Christian Robbie , Sims Sharanie , Zappernick Taissa , Wilson Brigid , Perez Federico , Bonomo Robert A , Jump Robin L 
Published: October 2019

Abstract

Background
Respiratory specimens help inform the treatment of hospital-acquired pneumonia (HAP), permitting clinicians to ensure effective and, ideally, narrow-spectrum antibiotic therapy. Here, we examine changes in antibiotic regimens to treat HAP based on the antibiotic susceptibility of pathogens recovered from respiratory samples.

Methods
At a single Veterans Affairs (VA) Medical Center, we identified veterans hospitalized between October 2014 and September 2018 with HAP, defined as a clinical respiratory sample obtained >48 hours after admission and corresponding clinical signs and symptoms. Exclusion criteria were death, transfer to hospice care or discharge within 48 hours of sample collection or admission from an outside hospital. For each specimen, we assessed timestamps for collection, Gram stain, identification of organisms and results of susceptibility testing. We used the antibiotic spectrum index (ASI) to assess changes in antibiotics given to patients during hospitalization and at discharge.

Results
Between October 2014 and September 2018, 70 veterans met our inclusion criteria and experienced 73 episodes of HAP. Their mean age was 66.2 years (±9 years) and 47 (67%) had chronic pulmonary disease. All-cause mortality at 30-days after specimen collection was 14%. The median time from specimen collection to Gram stain result was 0.8 days (interquartile range (IQR) 0.1–1.9) and to antibiotic susceptibility results was 2.4 days (IQR 1.5–3.3). The most common bacteria recovered were Enterobacteriaceae (20 isolates), Pseudomonas aeruginosa (11 isolates), Streptococcus spp. and Staphylococcus aureus (8 isolates each); colonization with Candida spp. was frequent (26 isolates). Vancomycin and piperacillin–tazobactam were the most common antibiotics on day 0 (24%, 22%, respectively) and day 3 (21%, 13%, respectively). Compared with the day of sample collection (day 0), the ASI score was lower at day 3 in 23 (32%) and higher in 21 (29%) cases.

Conclusion
The high proportion of escalation and de-escalation of antibiotics suggests that results of bacteria identification and susceptibility testing influence therapeutic decisions, emphasizing the importance of obtaining respiratory samples to inform treatment of HAP and improve antibiotic stewardship.

Disclosures
All authors: No reported disclosures.
2192. Comparative Antimicrobial Susceptibility of Gram-Negative Bacteria Isolated from Patients with Bloodstream Infections and Pneumonia when Tested against Tazobactam Combinations
Authors: Carvalhaes Cecilia G , Mendes Rodrigo E , Flamm Robert K , Sader Helio S 
Published: October 2019

Abstract

Background
Cefepime–tazobactam (FEP-TAZ) is in clinical development at 2g/2g q8 hours administered over 90 minutes (high-dose extended infusion). We compared the susceptibility (S) of Gram-negative bacilli (GNB) from patients with bloodstream infections (BSI) and pneumonia (PN) against FEP-TAZ, piperacillin–tazobactam (PIP-TAZ), and ceftolozane–tazobactam (C-T).

Methods
In 2018, 3,389 GNB isolates (1/patient) were consecutively collected from patients with BSIs (1,349) and PN (2,040) in 40 United States (US) medical centers, and tested by reference broth microdilution methods for S against FEP-TAZ (TAZ at fixed 8 mg/L), PIP-TAZ, C-T, and comparators. The percentage of isolates inhibited at ≤8 mg/L (CLSI, cefepime high dose) and at ≤ 16 mg/L (pharmacokinetic/pharmacodynamic [PK/PD] S breakpoint based on extended infusion and high dosage) of FEP-TAZ were evaluated.

Results
FEP-TAZ (MIC50/90, 0.06/0.25 mg/L) was the most active TAZ combination against Enterobacterales (ENT) with a spectrum similar to that of meropenem (MEM; 99.3/97.2%S for BSI/PN), ceftazidime–avibactam (CAZ-AVI; 99.8/99.9%S), and amikacin (AMK; 99.3/98.3%S) and retained good activity against ceftriaxone-non-S (CRO-NS) and multidrug-resistant (MDR) ENT (table). Among the β-lactams (BLMs) tested, only FEP-TAZ (57.1/58.6% [BSI/PN] inhibited at ≤ 16 mg/L) and CAZ-AVI (71.4/96.6%S) were active against carbapenem-resistant ENT (CRE). CAZ-AVI (96.7/95.2%S for BSI/PN) and C-T (96.5/94.5%S) were the most active BLMs tested against P. aeruginosa (PSA), followed by FEP-TAZ (95.0/92.1% inhibited a ≤ 16 mg/L), FEP (89.3/78.2%S), and CAZ (85.1/79.0%S). FEP-TAZ (77.8/77.3% inhibited at ≤ 16 mg/L), C-T (81.2/82.9%S), and CAZ-AVI (77.8/84.5%S) retained activity against MEM-NS PSA. FEP-TAZ was the most active BLM against Acinetobacter spp. when the proposed PK/PD breakpoint was applied.

Conclusion
S rates were markedly lower among isolates from PN compared with BSI. FEP-TAZ was the most active TAZ combination tested against GNB isolated from patients with BSI and PN from US hospitals and exhibited greater spectrum than the carbapenems. The results of this study support further clinical development of high-dose extended-infusion FEP-TAZ for treatment of GNB infections.

Disclosures
All authors: No reported disclosures.
2194. Procalcitonin-Guided Antibiotic Strategy for Lower Respiratory Tract Infections: Outcomes and Safety of Withholding Antibiotics
Authors: Bambino Geno Tai Don , Goldstein Robert 
Published: October 2019

Abstract

Background
Procalcitonin (PCT) is a promising and well-studied marker in differentiating viral from bacterial lower respiratory tract infections (LRTI). Antibiotics are not recommended when PCT is normal (< 0.25 μg/L). Despite this, it has not been the standard of care due to safety concerns of relying on PCT to withhold antibiotics.

Methods
We retrospectively reviewed all non-critical LRTI patients with normal PCT admitted in our institution from October 2018 to March 2019. They were divided into adherent group in whom antibiotics were discontinued within 24 hours and non-adherent group in whom antibiotics were continued. Cases of Legionella, Mycoplasma, and other infectious syndromes necessitating antibiotics were excluded. Complexity of cases was measured based on Centers for Medicare and Medicaid Services (CMS) case-mix index (CMI). Outcomes compared were the length of stay (LOS), in-hospital mortality, and 30-day all-cause readmissions.

Results
A total of 78 patients were included in the analysis, 52% (n = 41) were in adherent group and 48% (n = 37) in the non-adherent group. The mean age was 74, and majority were females (59%, n = 46). The were no significant differences between the two groups in terms of age, gender, CMI, underlying COPD/asthma, CHF (see Table 1). The adherent group had statistically shorter LOS compared with the non-adherent group after adjusting for CMI. There was no significant difference in In-hospital mortality and readmissions (see Table 2). Furthermore, the adherent group’s LOS was statistically similar to CMS average LOS (5.08 vs. 3.8, P = 0.08); compared with the non-adherent group which had statistically longer LOS compared with CMS average LOS (8.3 vs. 4.6, p

Conclusion
PCT is a safe tool in deciding when to withhold antibiotics on LRTI patients. It shortens LOS with no difference in mortality or readmission.

Disclosures
All authors: No reported disclosures.
2195. Incidence of Acute Myocardial Infarction in Patients with Community-Acquired Pneumonia: A Systematic Review and Meta-Analysis
Authors: Nieto Dominguez Alejandro , Furmanek Stephen , Ramirez Julio 
Published: October 2019

Abstract

Background
Community-acquired pneumonia (CAP) is a respiratory disease that is responsible for an estimated 3.5 million worldwide deaths annually. In the last few years, it has been hypothesized that CAP is implicated in the development of diseases in other systems such as renal and cardiovascular. Until this moment, multiple studies evaluating incidence of acute myocardial infarction (AMI) in patients with CAP exist, but data are still unclear. Our objective was to summarize several studies available regarding incidence of Acute Myocardial Infarction (AMI) in patients with CAP and to compare such value with the incidence of AMI in the general population.

Methods
We conducted a systematic review of articles published between January 1980 and January 2019 in the PubMed and PubMed Central databases. Studies describing the incidence of AMI in patients with CAP were included. We extracted their diagnostic criteria for CAP and AMI, and their AMI follow-up periods. In addition to this, we calculated cumulative incidence of AMI in patients with CAP and compared such value with the general population.

Results
1841 studies were identified (Figure 1), of which 10 studies were included in our review (Figure 2). From a forest plot-random effects model, the cumulative incidence of AMI among patients hospitalized due to CAP was 2,440 per 100,000 (95% CI: 1,780; 3,320) (Figure 3). Using the age-adjusted incidence of 649 cases of CAP per 100,000 adults described by Ramirez et al., we estimated that 16 per 100,000 adults will have an AMI associated with CAP (95% CI: 12;22) per year in the US Moreover, Yeh et al. found that the incidence of AMI in the general population was 208 per 100,000 people, comparing this value, to the values obtained in our meta-analysis of 2,440 acute myocardial infarctions by 100, 000 people, we can infer that adult patients hospitalized due to CAP have an 11.7-fold increase from the general population for risk of MI.

Conclusion
A higher risk of AMI was observed among adults hospitalized with CAP compared with the general population. Results must be carefully analyzed given the heterogeneity of the studies. At a clinical level, this increase in AMI incidence in patients with CAP should be taken into account in order to give the best therapeutic management to such patients.

Disclosures
All authors: No reported disclosures.
2196. Impact of Rapid Discontinuation of Empiric Vancomycin in Patients with Hospital-Acquired or Healthcare-Associated Pneumonia and Absence of Adequate Respiratory Tract Culture Data
Authors: Rufe Alanna H , Johnson Linda S 
Published: October 2019

Abstract

Background
Vancomycin is a commonly utilized empiric therapy for patients with hospital-acquired and healthcare-associated pneumonia (HAP and HCAP). De-escalation is encouraged in the guidelines but not commonly performed in the absence of culture data. Studies have shown that in certain low-risk patients, vancomycin may not be necessary. A clinical criterion document was implemented in 2018 at CHI Memorial to facilitate rapid de-escalation of vancomycin. This study aims to assess the impact of early discontinuation of vancomycin in patients with HAP or HCAP and no respiratory culture.

Methods
A retrospective cohort analysis was conducted in adult inpatients who presented from September to December 2017 and 2018 with HAP or HCAP, no respiratory culture within 72 hours, and at most one risk factor for MRSA. Patients who did not meet criteria for de-escalation, were receiving antibiotics for an extrapulmonary infection, or had a pathogen identified from blood or urinary antigen tests were excluded. The primary endpoint was vancomycin days of therapy pre- vs. post-intervention. Secondary endpoints include vancomycin re-start, subsequent respiratory culture growing MRSA, intensive care unit (ICU) and total length of stay, total days of antibiotic therapy, total days of alternate anti-MRSA therapy and in-hospital mortality in de-escalated vs. non-de-escalated patients.

Results
A total of 66 patient were included; 25 in the pre- and 41 in the post-period. The median age was 83 in the pre- and 68 in the post-period, with 20% of patients being initiated in the ICU and one patient with HAP in each group. There was no difference in median days of vancomycin therapy in the pre- vs. post-intervention period (4 days [3–5] vs. 4 days [3–5]) P = 0.583. There were 37 patients not de-escalated and 29 patients rapidly de-escalated. Total days of inpatient antibiotic therapy was significantly lower in the de-escalated group (7 days [5–9] vs. 5 days [4–7]) P = 0.037. No other significant differences were noted (Table 2).

Conclusion
There was no difference in vancomycin days of therapy after the implementation of this pharmacist-led initiative. However, discontinuing vancomycin within 72 hours was safe in patients with HCAP and was associated with decreased days of inpatient antibiotic therapy.

Disclosures
All authors: No reported disclosures.