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Background Gram-negative pathogens, such as Escherichia coli, are common causes of bloodstream infections (BSIs) and increasingly demonstrate antimicrobial resistance. Molecular rapid diagnostic tests (mRDTs) offer faster pathogen identification and susceptibility results, but higher costs compared with conventional methods. We determined the cost-effectiveness of the BioFire FilmArray Blood Culture Identification (BCID) Panel, as a type of mRDT, compared with conventional methods in the identification of E. coli BSIs. Methods We constructed a decision analytic model comparing BCID with conventional methods in the identification and susceptibility testing of hospitalized patients with E. coli BSIs from the perspective of the public healthcare payer. Model inputs were obtained from published literature. Cost-effectiveness was calculated by determining the per-patient admission cost, the QALYs garnered and the incremental cost-effectiveness ratios (ICERs) where applicable. Monte Carlo probabilistic sensitivity analyses and one-way sensitivity analyses were conducted to assess the robustness of the model. All costs reflect 2019 Canadian dollars. Results The Monte Carlo probabilistic analyses resulted in cost savings ($27 070.83 versus $35 649.81) and improved QALYs (8.65 versus 7.10) in favour of BCID. At a willingness to pay up to $100 000, BCID had a 72.6%–83.8% chance of being cost-effective. One-way sensitivity analyses revealed length of stay and cost per day of hospitalization to have the most substantial impact on costs and QALYs. Conclusions BCID was found to be cost-saving when used to diagnose E. coli BSI compared with conventional testing. Cost savings were most influenced by length of stay and cost per day of hospitalization.

Background Staphylococcus aureus bacteriuria (SABU) may represent multiple processes ranging from asymptomatic colonization to a marker of S. aureus bacteremia (SAB). Our objective was to describe SABU at a population-based level and determine patient characteristics associated with SAB. Methods A retrospective study was performed using electronic databases. All urine cultures positive for S. aureus between 2010 and 2013 within the Calgary Health Zone were included. Patient characteristics were compared among patients with and without SAB and risk factors identified using multiple logistic regression modeling. Results A total of 2540 urine cultures positive for S. aureus from 2054 patients were analyzed. The incidence of SABU was greatest among geriatric males with multiple comorbidities. SAB occurred in 175 (6.9%) of SABU patients. Those with SAB were more likely to be hospitalized, male, have a recent urinary procedure, have pure S. aureus culture in urine, and have laboratory findings suggesting systemic infection. Patients with isolated SABU were more likely to be ≥65 years, have dementia, and have abnormal urinalyses with pyuria and urine nitrites. In-hospital mortality in patients with SABU and SABU+SAB was 9.2% and 17.5%, respectively. Patients with SABU detected ≥48 hours before SAB had the highest risk of death. Conclusions Less than 7% of patients with SABU have or will develop SAB. Characteristics associated with SABU were identified that established higher risk for systemic infection. Investigating SABU patients with these characteristics for systemic infection is warranted because a delay in diagnosis is associated with increased mortality.

Background PLA is a significant cause of morbidity and mortality. However, its epidemiology and outcomes have not been recently evaluated in the CHZ. Understanding current trends will help guide management. Methods In this population-based study, we evaluated epidemiology, risk factors, and treatment of patients with PLA in the CHZ. CHZ residents aged ≥ 20 years diagnosed with PLA in 2015-2017 were included. Charts were reviewed for demographics and clinical outcomes. Multivariate logistic regression was used to determine factors associated with 30-day mortality. Findings were compared to a previous assessment of PLA in the CHZ from 1999-2003 (Kaplan et al., 2004). Results A total of 136 patients with PLA were identified, representing an annual incidence rate of 3.7 cases per 100,000 population. Compared to 1999-2003, incidence of PLA was increased (2.3 per 100,000; p< 0.01) but mortality was similar (1999-2003: 0.22 per 100,000 vs. 2015-2017: 0.26 per 100,000; p=0.6). The most common culprit organisms were Streptococcus anginosus group (40%), Klebsiella species (25%), Escherichia coli (18%), and obligate anaerobes (16%). Pathogen prevalence was similar to the prior cohort. Compared to 1999-2003, antibiotic resistant organisms were more frequent (8% vs 1%, p=0.04). In our cohort, liver aspirations were less frequent (p=0.02) but aspirate culture was more often positive (p< 0.01). The median duration of intravenous antibiotic therapy was longer compared to previous (2015-2017: 23 days (IQR 9-38) vs. 1999-2003: 17 days (IQR 10-29); p=0.001). Similarly, the total duration of antibiotic therapy was longer (2015-2017: 42 days (IQR 25-65) vs. 1999-2003: 31 days (IQR 18-45); p< 0.001). Thirty-day mortality from admission was 7% and did not differ amongst cohorts. Risk factors are shown in Table-1. Table-1: Risk factors for 30-day mortality in PLA Conclusion Incidence of PLA in the CHZ is rising with more antimicrobial resistance. Diagnostic liver aspirations are less frequent. Antibiotic durations are longer with no reduction in mortality. Understanding changing trends is valuable in directing future care. Encouraging liver aspirations to obtain a microbiologic diagnosis, especially with increasing resistance, is crucial. Considering shorter antibiotic durations in light of stable mortality warrants further exploration. Disclosures All Authors: No reported disclosures

Background The recognition of infective endocarditis (IE) as a serious complication of SAB has led to a low threshold for echocardiography, extended treatment (eTx) with anti-staphylococcal agents (anti-SA), and even surgery. However, indications for eTx outside of IE are numerous. We sought to determine the frequency in which findings from a TEE changed clinical SAB management. Methods Adults with SAB within the Calgary Health Zone between 2012 and 2014 were included if both a transthoracic echocardiogram (TTE) and TEE were performed within 7 days of each other. Patients potentially benefiting from eTx courses were a priori defined as having ≥1 of; (1) metastatic phenomena, (2) complicated SAB (defined as community acquired (CA), persistent fever/bacteremia at ≥48 hours), (3) intracardiac devices, and/or (4) Duke criteria defined IE (separately evaluated using TTE or TEE). Patient demographics, treatment (including changes to anti-SA duration and surgical indications), and clinical outcomes were extracted and evaluated. Results Of 961 SAB episodes, 179 (18% MRSA) met inclusion criteria (median 3.0 days, IQR 1.9–5.1 between TTE and TEE). Within the cohort 29% (n = 51) had metastatic phenomena (intracranial; 9% [n = 16], vertebral; 8% [n = 14]; empyema; 6% [n = 11]). Complicated bacteremia was present in 89% (n = 159), while 13% (n = 23) had intravascular hardware (39% pacemakers, 65% valve prostheses). IE was diagnosed in 22% (n = 40) of SAB episodes, with TTE identifying 58% of vegetations (n = 23) and TEE identifying an additional 30% (n = 15). Of the cohort, 89% (n = 160), 37% (n = 67), 4% (n = 7) of SAB had ≥1, 2, and 3 nonechocardiographic indications for eTx, respectively. Only one patient met criteria for eTx solely based on IE diagnosed from concordant TTE and TEE. Actual duration of therapy did not differ in SAB episodes that had ≥1 a priori eTx criteria but had a negative TEE relative to those who had a positive TEE (36.7 days, IQR 23.4–48.6 vs. 43.8 days, IQR 33.3–49.5, P = 0.17). Of the 15 episodes of TEE-only evident IE, 14 were CA, 12 had prolonged BSI, and nine embolic phenomena. Only 11 patients in the cohort required cardiac surgery, none were identified exclusively by TEE. Conclusion Routine performance of TEE may not be required in all SAB as many patients have alternate indications for eTx with anti-SA regardless of TEE findings. Disclosures All authors: No reported disclosures.

Background We previously identified foreign travel as a risk factor for acquiring infections due to CTX‐M (active on cefotaxime first isolated in Munich) producing Escherichia coli . The objective of this study was to assess the prevalence of extended‐spectrum β‐lactamase (ESBL)‐producing E coli among stool samples submitted from travelers as compared to non‐travelers (a non‐traveler had not been outside of Canada for at least 6 months before submitting a stool specimen). Methods Once a travel case was identified, the next stool from a non‐traveler (not been outside of Canada for at least 6 months) was included and cultured on the chromID‐ESBL selection media. Molecular characterization was done using polymerase chain reaction and sequencing for bla CTX‐Ms, bla TEMs, bla SHVs, plasmid‐mediated quinolone‐resistant determinants, O25‐ST131, phylogenetic groups, pulsed‐field gel electrophoresis (PFGE), and multilocus sequencing typing. Results A total of 226 individuals were included; 195 (86%) were negative, and 31 (14%) were positive for ESBL‐producing E coli. Notably, travelers were 5.2 (95% CI 2.1–31.1) times more likely than non‐travelers to have an ESBL‐producing E coli cultured from their stool. The highest rates of ESBL positivity were associated with travel to Africa or the Indian subcontinent. Among the 31 ESBL‐producing E coli isolated, 22 produced CTX‐M‐15, 8 produced CTX‐M‐14, 1 produced CTX‐M‐8, 12 were positive for aac(6 ′ )‐Ib‐cr , and 8 belonged to clone ST131. Conclusions Our study confirms that foreign travel, especially to the Indian subcontinent and Africa, represents a major risk for rectal colonization with CTX‐M‐producing E coli and contributed to the Worldwide spread of these bacteria.

Objectives A study was designed to determine the prevalence of plasmid-mediated quinolone resistance (PMQR) determinants among clinical isolates of Enterobacteriaceae from the Calgary Health Region (CHR). Methods During January and February 2004 and January and February 2007, 564 non-repeat isolates of Escherichia coli, Klebsiella spp., Proteus mirabilis and Morganella morganii resistant to ciprofloxacin and/or tobramycin were screened for PMQR determinants using a multiplex PCR for qnrA, qnrS and qnrB and aac(6')-Ib genes; aac(6')-Ib-cr was further identified by digestion with BstF5I. Results In 2004, 6/139 (4%) of the resistant E. coli were positive for aac(6')-Ib-cr. In 2007, 53/398 (13%) were positive for aac(6')-Ib-cr, 3/398 (0.8%) were positive for qnrS, and one isolate was positive for both. All the isolates were present in urines and the majority [40/63 (63%)] were submitted from community collection sites; 8 (13%) isolates co-produced AmpC beta-lactamases and 34 (54%) co-produced CTX-M-15. aac(6')-Ib-cr was present in one Klebsiella pneumoniae and one P. mirabilis, whereas one isolate of K. pneumoniae was positive for both aac(6')-Ib-cr and qnrB. Conclusions Our results showed that isolates with aac(6')-Ib-cr, often associated with CTX-M-15, are emerging among fluoroquinolone-resistant E. coli in the CHR. Our study suggests that surveillance for PMQR determinants should be undertaken on a regular basis.

Background A study was conducted in the Calgary Health Region between May 2002 and April 2004 to define the population-based epidemiological characteristics of infections caused by imipenem-resistant Pseudomonas aeruginosa and to explore the clinical outcomes due to metallo- beta -lactamase (MBL)-producing and non-MBL-producing strains. Methods Detailed clinical information was obtained by chart review, and phenotypic and molecular characterizations were performed using the MBL E-test, polymerase chain reaction with sequencing, and pulsed-field gel electrophoresis. Results A total of 228 patients with infections caused by imipenem-resistant P. aeruginosa were identified (annual incidence, 10.5 cases/100,000 population), with the highest incidence rate in those >or=75 years old. MBL-producing strains (98/228) were associated with higher rates of multidrug resistance and bacteremia. Ninety MBL-producing strains also produced VIM-2, 4 produced IMP-7, and 4 were unclassified. A cluster of VIM-2-producing strains was responsible for a nosocomial outbreak during 2003. The case-fatality rate was significantly higher for infections caused by MBL-producing strains than for those caused by non-MBL-producing strains (25% vs. 13%; relative risk, 1.98 [95% confidence interval, 1.00-3.90]; P=.05). Conclusion MBL-producing P. aeruginosa strains were associated with a higher case-fatality rate and invasive disease. Our study highlights the potential importance of molecular laboratory techniques in infection control and patient care.