bluuebunny/crossref_metadata_2025_split huggingface dataset:
487. Prevalence of Antimicrobial Resistance in Gram-Negative Bacilli Bloodstream Infections at a Tertiary Teaching Hospital in the Dominican Republic
Authors: Mena Lora Alfredo J , Rodriguez Abreu Julia , Blanco Claudia , de Lara Jacquelin , Bleasdale Susan C 
Published: October 2019

Abstract

Background
Bloodstream infections (BSI) with gram-negative bacilli (GNB) are a major cause of morbidity and mortality worldwide. Sepsis due to BSI can carry a mortality rate as high as 40%, with higher mortality in developing nations. Early and appropriate empiric therapeutic selection plays an important role in survival. The rising incidence of antimicrobial resistance (AMR) limits empiric treatment options. Local susceptibility patterns can vary per region, institution or setting. Understanding local AMR may help guide empiric treatment choices. We seek to describe resistance rates for GNB BSI in the Dominican Republic (DR).

Methods
This is a retrospective review of antimicrobial susceptibility patterns from bloodstream infections in a tertiary hospital in the DR. Susceptibility data from all adult inpatient blood cultures were collected from January 1 to December 31, 2017.

Results
A total of 124 blood cultures were reported. The most common organisms were Escherichia coli (43%) and Klebsiella pneumoniae (23%). Fluoroquinolone resistance was present in 70% of E. coli. Phenotypic susceptibility patterns consistent with extended-spectrum β-lactamase (ESBL) producing GNB were present in 46% of isolates. Carbapenem resistance was found in 4 samples and was most common in P. aeruginosa. Susceptibility profile is described on Table 1.

Conclusion
AMR was high in GNB BSIs in the DR. High rates of ESBL render common cephalosporins sub-optimal for empiric treatment. PTZ retains in vitro susceptibilities despite cefepime resistance but clinical efficacy is controversial. CTX-M ESBLs may cause these resistance pattern in vitro. Further studies are needed to determine genetic mechanisms of resistance. Establishing antimicrobial stewardship programs with rapid diagnostic testing that identify mechanisms of resistance may promote judicious use of carbapenems and reduce further the risk of further development of AMR.

Disclosures
All authors: No reported disclosures.
507. Epidemiology of Community-Associated Carbapenemase + Producing Carbapenem-Resistant Enterobacteriacae Identified from the Emerging Infections Program, 2012–2017
Authors: See Isaac , Ansari Uzma , Reses Hannah , Grass Julian E , Epson Erin , Nadle Joelle , Bamberg Wendy M , Janelle Sarah J , Bower Chris W , Jacob Jesse T , Vaeth Elisabeth , Wilson Lucy E , Lynfield Ruth , VonBank Brittany , Snippes Vagnone Paula , Hancock Emily B , Phipps Erin C , Dumyati Ghinwa , Tsay Rebecca , Cassidy Maureen , Kainer Marion A , Mounsey Jacquelyn , Muleta Daniel , Bulens Sandra N , Karlsson Maria , Duffy Nadezhda , Lutgring Joseph 
Published: October 2019

Abstract

Background
Carbapenemase-producing (CP-) carbapenem-resistant Enterobacteriaceae (CRE) have been almost exclusively linked to extensive healthcare exposure and are of significant concern due to limited treatment options and potential for plasmid-mediated spread of resistance. We report on CP-CRE in community-dwelling individuals.

Methods
We used 2012–2017 active, laboratory and population-based surveillance data for CRE from CDC’s Emerging Infections Program sites (9 sites by 2017). Cases were the first isolation of Escherichia coli, Klebsiella spp., or Enterobacter spp. from a normally sterile body specimen or urine in a surveillance site resident meeting a CRE phenotype (figure) in a 30 day period. Epidemiologic data were obtained from chart review. Cases were community-associated (CA) if not isolated after the first three days of a hospital stay; without inpatient healthcare, dialysis, or surgery in the year prior; and without indwelling medical devices within two days prior to culture. A convenience sample of isolates was tested at CDC by real-time PCR to detect blaKPC, blaNDM, blaOXA-48-like, blaVIM, or blaIMP.

Results
Of 4023 CRE cases, 699 (17%) were CA, from which 297 isolates were tested; 20 (7%) were CP-CRE, from 18 patients (2 had repeat isolation of the same gene/species). The median age was 68 years (range: 33–91), and 14 (78%) were female. Patients were from 7 sites (range: 1–4/site). Their CP-CRE (10 blaKPC, 6 blaNDM, and 2 blaOXA-48-like) were from three species (10 K. pneumoniae, 6 E. coli, 2 E. cloacae) and isolated from urine (n = 16) and blood (n = 2). Among those with CP-CRE from urine, 12 (75%) had clinical diagnoses of urinary tract infections and the rest had no infection documented. Overall, 7 (39%) were admitted to a hospital within 30 days of culture; none died during hospitalization. Most (n = 13; 72%) had underlying medical comorbidities, most commonly urinary tract abnormalities (n = 5; 28%) and diabetes mellitus (n = 5; 28%). Three (17%) had international travel within two months prior to culture.

Conclusion
CA CP-CRE were found in most surveillance sites but are rare, occurring primarily in older patients with underlying medical conditions. Patient interviews are planned to determine whether CA CP-CRE may be associated with distant or undocumented healthcare exposures.

Disclosures
All authors: No reported disclosures.
515. Acquisition of Antibiotic-Resistant Gram-Negative Bacteria in the Benefits of Universal Glove and Gown (BUGG) Cluster Randomized Trial
Authors: Harris Anthony , Morgan Daniel , Harris Lisa , Magder Laurence S , O’Hara Lyndsay M , Johnson Kristie 
Published: October 2019

Abstract

Background
The Benefits of Universal Gloves and Gowns (BUGG) randomized trial found a decrease in MRSA acquisition, no effect on VRE acquisition and no increase in adverse events with the intervention of wearing gloves and gowns for all patient contact in the intensive care unit (ICU). The objective of the study was to assess whether wearing gloves and gowns for all patient contact in the ICU decreases the acquisition of antibiotic-resistant Gram-negative bacteria.

Methods
Design: Secondary study of the BUGG cluster-randomized trial.
Participants: 20 medical and surgical ICUs in 20 US hospitals.
Intervention: Healthcare workers were required to wear gloves and gowns when entering any patient room compared with standard care. Main outcomes and measures: The primary composite outcome was acquisition of any antibiotic-resistant Gram-negative bacteria based on surveillance cultures collected on admission and discharge. Secondary outcomes were acquisition of carbapenem-resistant Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacteriaceae, or ESBL-producing Enterobacteriaceae.

Results
For the primary outcome, the intervention had a RR of 0.90 (95% CI 0.71 to 1.12, P = 0.34). Effects on the secondary outcomes were: carbapenem-resistant Enterobacteriaceae [RR 0.86 (95% CI, 0.60 to 1.24), P = 0.43], carbapenem-resistant Acinetobacter [RR 0.81 (95% CI, 0.52 to 1.27) P = 0.36], carbapenem-resistant Pseudomonas [RR 0.88 (95% CI, 0.55 to 1.42) P = 0.62], ESBL producing bacteria [RR 0.94, (95% CI, 0.71 to 1.24) P = 0.67].

Conclusion
The association of universal glove and gown use in the ICU with acquisition of antibiotic-resistant Gram-negative bacteria was inconclusive. The observed rate ratios for all five outcomes suggest that the intervention was protective, however, none were statistically significant. The study was likely underpowered to detect statistical significance for the effect sizes found. Individual hospitals should consider implementing the intervention based on the importance of these organisms at their hospital, effect sizes, confidence intervals, and cost.

Disclosures
All authors: No reported disclosures.
517. Treatment Patterns of Hospitalized Adults with Infections Due to Carbapenem Non-Susceptible Gram-Negative Organisms in a Large Electronic Health Record Database in the United States
Authors: Burton Tanya , Anderson Amy , Seare Jerry , Dillon Ryan J , McCann Eilish 
Published: October 2019

Abstract

Background
Infections caused by carbapenem non-susceptible (C-NS) Gram-negative (GN) organisms pose a major threat, due in part to limited treatment options. The aim of this study was to assess treatment patterns for these infections in a large US electronic health record database.

Methods
A retrospective cohort study of hospitalized adults with complicated intra-abdominal infection (cIAI), complicated urinary tract infection (cUTI), bacterial pneumonia (BP), or bacteremia (BAC) due to C-NS (resistant/intermediate susceptibility to carbapenem) GN organisms from January 2013 to March 2018. Patients with inherently C-NS organisms (e.g., Pseudomonas aeruginosa to ertapenem) were only included if resistance to another carbapenem was identified. The index date was the date of first C-NS culture in a qualifying hospitalization (±3 days from admission/discharge). Clinical characteristics and administered treatments were assessed from admission to discharge with variables summarized descriptively and stratified by infection type.

Results
7,702 patients met inclusion criteria: 31% cUTI ± BAC, 24% BP ± BAC, 21% cUTI + BP ± BAC, 17% cIAI ± BAC, cUTI, or BP, 7% BAC only. The median age was 66 years, ranging from 60 (BAC) to 69 (cUTI) years; male, 57%. The most common pathogens were Pseudomonas aeruginosa (64%) and Klebsiella pneumoniae (15%). Antibiotics were administered to the majority of patients (87%); of which, 79% received combination therapy (median classes: 3, maximum: 7), the remainder received monotherapy. For antibiotic-treated patients, 93% initiated an antibiotic before the non-susceptibility status of the underlying organism was known. The most common classes given during the index hospitalization were: penicillin (49%), fluoroquinolone (44%), carbapenem (40%), cephalosporin (39%), aminoglycoside (28%) (by infection type, Figure 1). Eleven percent of patients received colistin/polymyxin B.

Conclusion
Varied antibiotic use was observed in this cohort, with carbapenems frequently detected despite the C-NS nature of the underlying GN organisms. The use of antibiotics to which organisms are non-susceptible could lead to poor health outcomes, supporting the need for new targeted therapies to treat C-NS infections.

Disclosures
All authors: No reported disclosures.
523. Dual vs. Triple Antibiotic Therapy for Carbapenem-Resistant Acinetobacter baumannii Infections
Authors: Markelwith Justin Patrick , Vyas Nikunj M , Condoluci Mark , Kim Sungwook 
Published: October 2019

Abstract

Background
Infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) remain some of the most difficult to treat due to extremely high rates of resistance. The purpose of this study was to compare the efficacy of dual vs. triple targeted antibiotic regimens for CRAB infections.

Methods
This was an IRB approved retrospective cohort study performed at a 607-bed community health system between January 2016 and December 2018. Patients were included in the analysis if they were ≥18 years old and received antibiotics for CRAB for ≥72 hours. Patients were excluded if they were pregnant and had CRAB isolated solely from the urine. The primary endpoints of the study were differences in all-cause in-hospital mortality (ACIM) and clinical cure (CC) rates for patients treated with dual vs. triple antibiotic therapy. The secondary endpoint result focused on the difference in length of stay (LOS) between treatment groups. A sub-group analysis was performed for patients treated with tigecycline vs. minocycline combination therapy to determine differences ACIM and CC, and LOS. A multi-logistic regression analysis (MLRA) was performed to determine patient factors that were associated with ACIM and CC.

Results
A total of 32 patients were included in the primary analysis. No difference was seen in ACIM between dual vs. triple antibiotic groups (9.5% vs. 18.2%, P = 0.59). CC (63.6% vs. 57.1%, P = 1.0) and LOS (12 vs. 11 days, P = 1.0) was similar amongst patients treated with dual vs. triple antibiotic group. No differences were seen in ACIM (15.4% vs. 16.7% P = 1.0), CC (83.3% vs. 69.2%, P = 1.0) and LOS (15 vs. 14 days, P = 1.0) between tigecycline and minocycline combination therapy groups. The MLRA revealed a positive association with increased serum creatinine and ACIM (OR 3.29, 95% CI 1.35–8.04; P = 0.009) as well as shorter time to appropriate antibiotic therapy and clinical cure (OR 1.49, 95% CI 1.02–2.20; P = 0.04). CRAB isolates were more likely to be susceptible to minocycline vs. tigecycline (83% vs. 18%, P = 0.003).

Conclusion
No differences were seen in ACIM, CC and LOS between dual vs. triple antibiotic groups. Minocycline tends to sustain better susceptibility toward CRAB vs. tigecycline. Elevated serum creatinine was found to be a predictor for ACIM while shorter time to appropriate antibiotic therapy was associated with CC.

Disclosures
All authors: No reported disclosures.
536. Challenges in Using MALDI-TOF Technology to Assess for KPC Resistance in Klebsiella pneumoniae isolates in America
Authors: Thompson Michael Christopher , Banach David , Nishimura Christina , Muyombwe Anthony 
Published: October 2019

Abstract

Background
The emergence of Klebsiella pneumoniae Carbapenemase-producing Enterobacteriaceae (KPC-E) has created a major public health concern. In clinical practice, rapid identification of KPC-KP has important implications for clinical management and infection control. In some settings matrix-assisted laser desorption ionization time of flight (MALDI-TOF) software has been used for rapid detection of KPC producing K. pneumoniae with high sensitivity and specificity. Genomic sequencing has determined that the 11.09 m/z peak is related to protein expression from the P109 gene found mostly in Tna4401a isoform among KPC-E. In our study, we evaluated the use of MALDI-TOF automated detection software to evaluate for KPC detection among a diverse group of KPC-E isolates.

Methods
We tested 52 KPC-E isolates from various hospitals in Connecticut and the Centers for Disease Control and Prevention (CDC) Antibiotic Resistance (AR) Bank. All specimens were verified as KPC-producing strains by detection of the blaKPCgene through polymerase chain reaction. Protein extraction using the standard extraction method was performed on sub-cultured isolates. Each isolate was tested three times on MALDI-TOF MS with the incorporated bio-subtype KPC module. An organism confidence or log score value of 2 or higher was considered valid.

Results
Among 52 tested KPC-K. pneumoniae isolates, 44 (85%) were from various hospitals in Connecticut, eight (15%) came from the AR Bank. Only 15 (25.1%) of the isolates were detected as KPC-producing using the MALDI-TOF KPC module. Further investigation by peak analysis confirmed all 15 isolates detected positive demonstrated a peak at 11.09 m/z. The 11.09 m/z peak was not found in the 37 specimens that were not detected.

Conclusion
The results from our study suggest low sensitivity using this software and contradicts results seen in previous European studies. The Tna4401a isoform is often seen in KPC-2 strains, which may be less prevalent in our sample of isolates, explaining the poor sensitivity of MALDI-TOF. Further study is needed to explore this finding and potential opportunities for MALDI-TOF for rapid identification of KPC-KP.

Disclosures
All authors: No reported disclosures.
537. Impact of Active Surveillance Testing (AST) on Rates of Hospital-acquired Carbapenem-Resistant Enterobacteriaceae (CRE)
Authors: Campbell Eileen , Kester Shelley , Layell Jessica , Neelakanta Anupama , Capraro Gerald A , Passaretti Catherine 
Published: October 2019

Abstract

Background
Active surveillance testing (AST) for Carbapenem-resistant Enterobacteriaceae (CRE) to identify and isolate asymptomatic carriers has been recommended to help prevent patient to patient transmission. Optimal screening population, frequency, and testing method remain a subject of debate.

Methods
Beginning in 2012, all clinical cultures yielding a CRE isolate in an 898-bed teaching hospital were reviewed to determine whether the isolate was hospital-acquired (HA). HA CRE rates per 10,000 patient-days were calculated. From 1/2013 to 6/2015, in-house, culture-based point prevalence surveys were performed on rectal swabs from rotating units using the CDC recommended method. 7/2015 through 8/2016, culture-based AST was outsourced to a reference laboratory and AST was expanded to include high-risk patients on admission with weekly sweeps on high-risk units. Of note, revised CLSI breakpoints were implemented by our laboratory in 7/2016, which resulted in an increase in CRE detections. Surveillance was suspended from September 2016 to January 2018 when we resumed AST utilizing in-house PCR for KPC, NDM, OXA48, IMP and VIM mechanisms. Rates of HA CRE were compared between surveillance periods. Cohorting of patients in select units, focus on hand hygiene and isolation, antibiotic stewardship, and CHG bathing were ongoing throughout all time periods.

Results
510 rectal swabs in 424 patients were positive for CRE. Additional clinical cultures yielding CRE were absent in 83% of those patients, so would otherwise have gone undetected. Of those patients with both positive AST and clinical culture, 70% had a positive AST result prior to their clinical culture (range 0–997 days, average 94 days, median 14.5 days prior to clinical culture). Compared with preceding periods with no surveillance, on admission and weekly CRE AST, whether utilizing culture based or PCR based screening, was associated with significantly lower rates of HA CRE. (See Table 1). Rates of HA CRE during the initial point prevalence AST period were unchanged compared with periods with no surveillance. Community-onset CRE did not significantly change in any of the time periods monitored (Figure 2).

Conclusion
On admission and weekly AST was associated with a significant decrease in HA CRE in a large teaching hospital.

Disclosures
All authors: No reported disclosures.
538. Extended-Spectrum β-Lactamase (ESBL): Producing Enterobacteriaceae Surveillance Pilot, New Mexico, 2017
Authors: Phipps Erin C , Flores Kristina , Hancock Emily B 
Published: October 2019

Abstract

Background
Extended-spectrum β-lactamase – producing (ESBL) Enterobacteriaceae pose a serious antibiotic resistance threat, yet gaps remain in our understanding of their epidemiology. New Mexico was one of five Emerging Infection Program (EIP) sites to participate in a surveillance pilot from October 1 to December 31, 2017.

Methods
A case was defined as a resident of Bernalillo County, NM with E. coli, Klebsiella pneumoniae, or Klebsiella oxytoca cultured from urine or normally sterile body sites resistant to at least one extended-spectrum cephalosporin and nonresistant to all carbapenem antibiotics tested. EIP staff assessed prior healthcare exposures, risk factors, and outcomes through medical record review.

Results
NM EIP identified 309 incident cases among 288 individuals; 263 medical records were reviewed. Cases ranged in age from 3–95 years, with a median age of 63 years. Most isolates were E. coli (n = 270, 87.4%); 35 (11.3%) were K. pneumoniae and 4 (1.3%) were K. oxytoca. The majority of isolates were cultured from urine (297, 96.1%). Blood cultures comprised 11 cases (3.6%). The majority of ESBL cultures were collected in an outpatient setting; 15% were collected from hospital inpatients and fewer than 5% from residents of a long-term care facility (LTCF) or long-term acute care hospital (LTACH). However, 21% of those collected in an outpatient setting, primarily the ED, were hospitalized within 30 days.
Over 60% of the cases had at least one relevant risk factor documented in their medical record. One-third had documented antimicrobial use in the prior month, 39% had been hospitalized in the year prior, and 19% had a urinary catheter in place in the 2 days prior to culture collection. Interestingly, while only 2% had documentation of international travel in the two months prior to culture, 18% had either documented international travel outside of that timeframe, or required the use of language interpretation, possibly indicating extensive time living internationally in the past.

Conclusion
Among residents of Bernalillo County, NM, ESBL isolates were predominantly E. coli, cultured from urine in outpatient settings. Over half had documentation of recognized risk factors, including prior hospitalizations, recent antibiotic use, or presence of indwelling devices.

Disclosures
All authors: No reported disclosures.
548. Carbapenem-Resistant Acinetobacter baumannii Antibiotic Susceptibility Testing and Antibiogram Formation, Connecticut 2017–2019
Authors: Paranandi Anu , Maloney Meghan , Grogan Erin , Macierowski Bobbie , Noel Diane , Razeq Jafar , Muyombwe Anthony , Leung Vivian 
Published: October 2019

Abstract

Background
Carbapenem-resistant Acinetobacter baumanii (CRAB) is an infectious disease threat with limited treatment options. Statewide CRAB reporting and isolate submission has been mandated in Connecticut (CT) since 2017, which allowed the creation of a statewide CRAB antibiogram to assist with empiric treatment options for CRAB.

Methods
Clinical CRAB isolates from 2017 through the first quarter of 2019 underwent carbapenemase and expanded susceptibility testing at the CT State Public Health Laboratory or the Antibiotic Resistance Laboratory Network regional lab for carbapenemase and expanded susceptibility testing. Susceptibility testing was done by broth microdilution and disk diffusion, and interpreted using Clinical and Laboratory Standards Institute breakpoints. Carbapenemase producers were detected by the modified carbapenem inactivation method. Polymerase chain reaction testing identified carbapenemase genes.

Results
Of the 64 CRAB isolates submitted, 40 remained after confirmation of carbapenem resistance, i.e., resistance to at least one carbapenem, and deduplication of patients. Of these, 19 were carbapenemase producers (CP), and 21 were non-carpabenemase producers (Non-CP). All isolates were non-susceptible to cefepime, ceftazidime, levofloxacin and all carbapenems. Colistin susceptibilities were available for 33 isolates, 32 (97%) of which were susceptible. Tobramycin susceptibilities were available for 31 isolates, only 10 (32%) of which were susceptible. Of the CP, all 15 were susceptible to colistin, but only 2 (14%) were susceptible to tobramycin. Of the Non-CP, 16 (89%) were susceptible to colistin, and 8 (47%) were susceptible to tobramycin. Most CRABs had a tigecycline minimum inhibitory concentration (MIC) of ≤2 μg/mL, with a higher proportion of Non-CP with lower MIC values than CP.

Conclusion
CRAB shows resistance to all carbapenems, and most non-carbapenem antibiotics except colistin and in rare circumstances tobramycin. Most CRAB isolates had tigecycline MICs of ≤2 μg/mL. The statewide antibiogram illustrates the lack of approved antibiotics for the treatment of CRAB, underscoring the importance of further antibiotic development for CRAB treatment.

Disclosures
All authors: No reported disclosures.