Background: There has been dramatic reduction in Haemophilus influenzae serotype b (Hib) since introduction of Hib vaccines, but children still experience serious invasive Haemophilus influenzae (Hi) disease caused by various serotype and non-typeable bacteria.The object of this study was to describe the serotype distribution and clinical spectrum of Hi bacteremia in children admitted to Canadian hospitals.Methods: All children with Hi bacteremia admitted 2013 through 2017 to 10 centres across Canada were included.Demographic, clinical, treatment and outcome data were collected.Results: Haemophilus influenzae bacteremia occurred in 118 children of median age 12 months (inter-quartile range: 7-48 months).Forty-three (36%) isolates were non-typeable (NTHi) and 8 were not typed.Of the 67 typeable (THi), Hia (H.influenzae serotype a) (n=36, 54%), Hif (serotype f) (n=19, 26%) and Hib (serotype b) (n=9, 13%) dominated.The THi was more likely than NTHi bacteremia to present as meningitis (p<0.001),particularly serotype a (p=0.04) and less likely to present as pneumonia (p<0.001).Complicated disease (defined as intensive care unit admission, need for surgery, long-term sequelae or death) occurred in 31 (26%) cases and were more likely to have meningitis (p<0.001)than were those with uncomplicated disease. Conclusion:In the era of efficacious conjugate Hib vaccines, NTHi, Hia and Hif have emerged as the leading causes of invasive Hi in Canadian children, with Hia being most likely to result in meningitis and complicated disease.A vaccine for all NTHi and THi would be ideal, but knowledge of the current disease burden from circulating strains will inform prioritization of vaccine targets.

Single molecule detection methods are becoming increasingly important for diagnostic applications. Practical Early detection of disease requires sensitivity down to the level of single copies of the targeted biomarkers. Of the candidate technologies that can address this need, solid-state nanopores show great promise as digital sensors for single-molecule detection. Here, we present work detailing the use of solid-state nanopores as downstream sensors for a PCR-based assay targeting group A streptococcus (strep A) which can be readily extended to detect any pathogen that can be identified with a short nucleic acid sequence. We demonstrate that with some simple modifications to the standard PCR reaction mixture, nanopores can be used to reliably identify strep A in clinical samples. We also discuss methodological best practices both for adapting PCR-based assays to solid-state nanopore readout as well as analytical approaches by which to decide on sample status.

Genome-wide variation in SARS-CoV-2 reveals evolution and transmission dynamics which are critical considerations for disease control and prevention decisions. Here, we review estimates of the genome-wide viral mutation rates, summarize current COVID-19 case load in the province of Ontario, Canada (5 January 2021), and analyze published SARS-CoV-2 genomes from Ontario (collected prior to 24 November 2020) to test for more infectious genetic variants or lineages.

Importance Community-acquired pneumonia (CAP) is a common occurrence in childhood; consequently, evidence-based recommendations for its treatment are required. Objective To determine whether 5 days of high-dose amoxicillin for CAP was associated with noninferior rates of clinical cure compared with 10 days of high-dose amoxicillin. Design, Setting, and Participants The SAFER (Short-Course Antimicrobial Therapy for Pediatric Respiratory Infections) study was a 2-center, parallel-group, noninferiority randomized clinical trial consisting of a single-center pilot study from December 1, 2012, to March 31, 2014, and the follow-up main study from August 1, 2016, to December 31, 2019 at the emergency departments of McMaster Children's Hospital and the Children's Hospital of Eastern Ontario. Research staff, participants, and outcome assessors were blinded to treatment allocation. Eligible children were aged 6 months to 10 years and had fever within 48 hours, respiratory symptoms, chest radiography findings consistent with pneumonia as per the emergency department physician, and a primary diagnosis of pneumonia. Children were excluded if they required hospitalization, had comorbidities that would predispose them to severe disease and/or pneumonia of unusual origin, or had previous β-lactam antibiotic therapy. Data were analyzed from March 1 to July 8, 2020. Interventions Five days of high-dose amoxicillin therapy followed by 5 days of placebo (intervention group) vs 5 days of high-dose amoxicillin followed by a different formulation of 5 days of high-dose amoxicillin (control group). Main Outcomes and Measures Clinical cure at 14 to 21 days. Results Among the 281 participants, the median age was 2.6 (interquartile range, 1.6-4.9) years (160 boys [57.7%] of 279 with sex listed). Clinical cure was observed in 101 of 114 children (88.6%) in the intervention group and in 99 of 109 (90.8%) in the control group in per-protocol analysis (risk difference, -0.016; 97.5% confidence limit, -0.087). Clinical cure at 14 to 21 days was observed in 108 of 126 (85.7%) in the intervention group and in 106 of 126 (84.1%) in the control group in the intention-to-treat analysis (risk difference, 0.023; 97.5% confidence limit, -0.061). Conclusions and Relevance Short-course antibiotic therapy appeared to be comparable to standard care for the treatment of previously healthy children with CAP not requiring hospitalization. Clinical practice guidelines should consider recommending 5 days of amoxicillin for pediatric pneumonia management in accordance with antimicrobial stewardship principles. Trial Registration ClinicalTrials.gov Identifier: NCT02380352.

Abstract Background Antimicrobial resistance is a public health threat, invasive infection from multi-drug resistant gram-negative (MDRGN) pathogens is associated with significant morbidity and mortality. The incidence of MDRGN bacteremia in Canada is rising, and pediatric data is limited. Methods This retrospective chart review of paediatric patients with gram negative bacteremia in a multicenter PICNIC database (n=7 centers) from 2013 to 2017. MDRGN was defined as enterobacteriaceae that were resistant to third generation cephalosporins (including ESBL, CPE). Ethics approval was obtained at all sites, and data was entered into a secure REDCAP database, descriptive statistics are described herein. Results Of the 676 bacteremia patients in the database, 214 (31.7%) were gram negative pathogens. E. coli was the most frequent pathogen (59.8%, of which 22 of 128 were MDR), followed by Klebsiella (31.8%, of which 9 of 68 were MDR). Of the 31 MDRGNs, 19 were ESBL, 1 was a CPE, and 11 were nonspecific mechanisms of resistance. There were no multidrug resistant Pseudomonas, Stenotrophomonas, or Acinetobacter. The majority of patient were less than 3 months of age (59.3%) and were male (58.8%). The majority had an underlying comorbid condition; hematoncologic diagnosis accounting for 14.5%. Length of stay varied from 1 to 742 days (mean 72, standard deviation 88). 11% required admission to ICU, 10% required removal of a intravascular catheter, 7% required a change in ventilation status, 2% requiring procedural source control, and there was an 8% mortality rate. Treatment duration greater than 14 days occurred in 123 patients (61% of patients). Conclusion This preliminary analysis of a multicenter review of pediatric gram negative bacteremias demonstrates a higher risk in neonates with comorbid conditions. A surprisingly prolonged treatment duration of greater than 14 days occurred in the majority of patients. Further analysis to assess factors associated with prolonged treatment durations, MDR infection, and complications is required. Gram negative bacteremia remains a significant cause of morbidity and mortality in pediatric patients. Disclosures All Authors: No reported disclosures

Contexte : La vaccination a entraîné une diminution de l'incidence de la méningococcie invasive au Canada, mais cette infection est toujours à l'origine d'un taux de morbidité et d'une mortalité important.Objectifs : L'objectif de cette étude était de déterminer la charge de morbidité et la gestion de la méningococcie invasive dans les hôpitaux pédiatriques.Méthodes : Des données ont été recueillies sur tous les cas de méningococcie invasive dans huit hôpitaux pédiatriques entre 2013 et 2017.Résultats : Il y a eu 17 cas de méningococcie invasive.Trois des huit hôpitaux n'avaient aucun cas.Un peu plus de la moitié des cas étaient du sérogroupe B (n = 9); un quart (n = 4) étaient du sérogroupe W; moins d'un quart (n = 3) étaient du sérogroupe Y; et un était inconnu.Deux enfants infectés n'ont commencé à prendre des antibiotiques qu'au premier et au cinquième jour après la première hémoculture, mais leur rétablissement s'est fait sans incident.Six cas ont nécessité une admission en unité de soins intensifs; deux sont morts.Six cas de méningite probable ou avérée.La thrombocytopénie a été documentée dans sept cas.Tous les cas présentaient des taux élevés de protéine C réactive.Sept enfants ont reçu plus de sept jours d'antibiotiques; sur ces sept enfants, seuls deux présentaient des complications justifiant un traitement prolongé (empyème sous-dural et genou septique).Un cathéter veineux central a été placé dans six cas. Conclusion :La méningococcie invasive est désormais rare chez les enfants canadiens, mais environ un tiers des cas de notre étude ont nécessité un traitement dans l'unité de soins intensifs et deux sont morts.Les cliniciens ne semblent pas toujours être conscients qu'un cours de cinq à sept jours est suffisant pour les cas simples de bactériémie ou de méningite.

Background: Infections with extended-spectrum β-lactamase–producing Enterobacteriaceae (ESBL-E) in nonoutbreak settings have not demonstrated the presence of dominant strains. Our objective was to determine the incidence, clinical characteristics, and genetic characteristics of ESBL-E infections among a group of Canadian children. Methods: From 2012 through 2017, patients aged ≤18 years with first-episode ESBL-E infections who presented at a pediatric center were reviewed. All clinical isolates were phenotypically identified in the laboratory as ESBL-producers. Demographic and clinical data were collected, including comorbid conditions, presence of devices, and previous antibacterial exposure. Community-associated infection was defined as a positive culture from a sterile site within the first 48 hours of hospital admission and no healthcare exposure during the preceding year. Isolates were sent to the Public Health Ontario Laboratory for whole-genome sequencing. Multilocus sequence typing was used to determine clonal relationship. Results: During the study period, 102 patients were identified with first-episode ESBL-E infection, and the proportion of ESBL-E isolates among all clinical isolates of E. coli and Klebsiella spp increased from 0.6% to 2.6% between 2012 and 2017, respectively (P = .001). The median age was 1 year (interquartile range, 0.8–5 years). Women comprised 66% of cases. No comorbid conditions were noted among 58 patients (57%), and 24% had previous antibiotic exposure, most frequently a cephalosporin (16%). ESBL-E was most frequently isolated in the urine (91%) and least frequently in the blood (2.2%) and was predominantly Escherichia coli (90%). Infection was most frequently diagnosed in the outpatient setting (61%); there were 11 healthcare-associated infections. Whole-genome sequencing of ESBL-E isolates revealed predominance of blaCTX-M-15 (63 isolates, 62%) and blaCTX-M-27 (16%) genes, and sequence type (ST) 131 (41%). Mutations conferring fluoroquinolone nonsusceptibility were noted among 62 isolates (61%), most frequently associated with ST131 (38 of 62 isolates, 61%) and among all 5 isolates with ST1193, an emerging multidrug-resistant E. coli clone. In addition, 15 patients had recurrence of ESBL-E infection at median of 113 days (IQR, 26–208); blaCTX-M-27 was found in 33% of recurrent infections compared to 12% of primary infections (P = 0.045). Conclusions: This study is the first in Canada to provide whole-genome sequencing data regarding ESBL-E in a pediatric population. The gene blaCTX-M-15 and ST131 clone were predominant. More than 60% of infections were community associated and demonstrated cross resistance to fluoroquinolones. With 76% of infections in antibiotic-naïve children, ESBL-E is a public health concern, and a One Health approach is critical to understanding the epidemiology and curbing the spread of multidrug-resistant Enterobacteriaceae.Funding: NoneDisclosures: None

OBJECTIVES:Our objective was to examine the performance characteristics of a bladder stimulation technique for urine collection among infants presenting to the emergency department (ED).METHODS:This prospective cohort study enrolled a convenience sample of infants aged ≤ 90 days requiring urine testing in the ED. Infants were excluded if critically ill, moderately to severely dehydrated, or having significant feeding issues. Bladder stimulation consisted of finger tapping on the lower abdomen with or without lower back massage while holding the child upright. The primary outcome was successful midstream urine collection within 5 minutes of stimulation. Secondary outcomes included sample contamination, bladder stimulation time for successful urine collection, and perceived patient distress on a 100-mm visual analog scale (VAS).RESULTS:We enrolled 151 infants and included 147 in the analysis. Median age was 53 days (interquartile range [IQR] 27-68 days). Midstream urine sample collection using bladder stimulation was successful in 78 infants (53.1%; 95% confidence interval [CI] 45-60.9). Thirty-nine samples (50%) were contaminated. Most contaminated samples (n = 31; 79.5%) were reported as "no significant growth" or "growth of 3 or more organisms". Median bladder stimulation time required for midstream urine collection was 45 seconds (IQR 20-120 seconds). Mean VAS for infant distress was 22 mm (standard deviation 23 mm).CONCLUSIONS:The success rate of this bladder stimulation technique was lower than previously reported. The contamination rate was high, however most contaminated specimens were easily identified and had no clinical impact.

BackgroundImmunizations have led to a decrease in the incidence of invasive meningococcal disease (IMD) in Canada, but this infection still leads to significant morbidity and mortality.ObjectivesThe purpose of this study was to determine the burden of illness and management of IMD in paediatric hospitals.MethodsData were collected on all cases of IMD in eight paediatric hospitals from 2013 to 2017.ResultsThere were 17 cases of IMD. Three of eight hospitals had no cases. Just over half of the cases were serogroup B (n=9); a quarter (n=4) were serogroup W; less than a quarter (n=3) were serogroup Y; and one was unknown. Two infected children were not started on antibiotics until day one and day five after the initial blood culture was collected, but had uneventful recoveries. Six cases required admission to intensive care units; two died. Six cases had probable or proven meningitis. Thrombocytopenia was documented in seven cases. All cases had elevated C-reactive protein levels. Seven children received more than seven days of antibiotics; of these seven, only two had complications that justified prolonged therapy (subdural empyema and septic knee). Six cases had a central line placed.ConclusionIMD is now rare in Canadian children, but about one-third of the cases in our study required treatment in the intensive care unit and two died. Clinicians appear to not always be aware that a five to seven-day course is adequate for uncomplicated cases of bacteremia or meningitis.

Abstract Background Community-acquired pneumonia (CAP) is a common occurrence in childhood; consequently, evidence-based recommendations for its treatment are required. The study objective was to determine if, in previously healthy children presenting to the emergency department (ED), 5 days of high-dose amoxicillin led to noninferior rates of clinical cure at 14–21 days post-enrolment compared with 10 days of high-dose amoxicillin. Methods The SAFER study was a multicentre, randomized, parallel-group, multiple-blinded, controlled, noninferiority study, enrolling between 2012–2014 (single centre pilot) and then 2016–2019 (follow-up main study). Children aged 6 months – 10 years with all of the following were eligible: fever within 48h; a respiratory symptom/sign; a chest radiograph consistent with pneumonia as per the emergency MD; and a primary diagnosis of CAP. Children were excluded if they required hospitalization, had any medical comorbidities, or if they were already receiving beta-lactam antibiotic therapy. The intervention of interest was 5 days of high-dose amoxicillin followed by 5 days placebo. The control (standard care) arm received 5 days of high-dose amoxicillin followed by a different formulation of 5 days of high-dose amoxicillin. The primary outcome was clinical cure at 14–21 days post-enrolment. The pre-set noninferiority margin was 0.075 less than the clinical cure risk difference (1-sided 97.5% CI). Results Of the 281 participants, 119 (42%) were female; the median age was 2.6 y (25–75%ile 1.6–4.9 y). There were 140 randomized to short-course treatment and 141 to standard care. Clinical cure at 14–21 days was observed in 108/126 (86%) in the short-course arm and in 106/126 (84%) in the standard-care arm (risk difference 0.023, lower limit of 1-sided 97.5%CI -0.061). There were no participants who, after finishing amoxicillin, later deteriorated and required hospitalization for progressive CAP. Conclusion Short-course antibiotic therapy was noninferior to standard care for the treatment of previously healthy children with non-severe CAP diagnosed in Canadian EDs. Clinical practice guidelines should recommend no more than 5 days of amoxicillin for paediatric pneumonia management, in accordance with antimicrobial stewardship principles. Disclosures All Authors: No reported disclosures

Abstract Background Our objective was to describe the serotype distribution and clinical spectrum of invasive Haemophilus influenza (Hi) disease in children admitted to participating centers within the Paediatric Investigator’s Collaborative Network on Infections in Canada (PICNIC). Methods All cases of Hi bacteremia were identified from the PICNIC Database of Gram-negative bacteremia (2013–2017). Disease was defined as complicated if the following occurred: (a) >2 sites were affected, (b) surgical intervention was required, (c) organ failure, (d) ICU admission, (e) seizures, (f) sensory or motor deficits, (g) treatment-related complications, or (h) death. Results There were 98 cases of Hi bacteremia. Male to female ratio was 64:34 and median age was 12 (IQR: 7–48; range 0–216) months. Hi serotypes included: a (N = 31; 32%), b (N = 9; 9%), f (N = 15; 13%), c (N = 1;1%), e (N = 1; 1%), nontypeable (N = 34; 35%) and unknown (N = 7; 7%). Clinical foci included: bacteremia without a focus (N = 19; 19%), meningitis (N = 29; 30%), cellulitis (N = 8; 8%), septic arthritis (N = 6; 6%), pneumonia (n = 33; 34%), epiglottitis (N = 1; 1%), and endovascular infection (n = 3; 3%). Complicated disease occurred in 29 (30%) cases; there was one (1%) death. Where serotyping was available, complication rates were: 42%, 22%, 100%, 0%, 33%, and 21% for Hia, Hib, Hic, Hie, Hif and nontypeable Hi, respectively. Factors associated with complicated disease were: age <5 years (P = 0.009), bacteremia without a focus (P = 0.006) and a CNS focus (P < 0.001). Hia was the leading serotype in meningitis (55%; P = 0.022). Nontypeable Hi was most frequent in pneumonia cases (56%; P = 0.003) and never caused cellulitis (0% vs. 14%; P = 0.023). Neonatal disease (N = 5) was predominantly caused by nontypeable Hi (80%; P = 0.040). Of note, 26 (27%) of our Hi isolates were ampicillin resistant. Conclusion In the era of efficacious conjugate Hib vaccines, serotype has emerged as the leading cause of typeable Hi disease in Canada and is highly associated with meningitis, especially in young children. Strategies for preventing Hi disease need to target this emerging serotype and efforts should be focused toward developing an effective vaccine for serotype a disease. Disclosures All Authors: No reported Disclosures.

We compared three commercially available group A Streptococcus (GAS) nucleic acid amplification tests, the Quidel Solana GAS assay, the Luminex Aries Group A Strep assay and the Focus Diagnostics Simplexa Group A Strep Direct assay, with GAS bacterial culture. A true positive result was defined as one positive by culture or positive by ≥2/3 molecular methods. Two hundred eighty-seven throat swabs (207 children, 80 adults) were collected. The sensitivity of culture was 84.8% (95% CI 77.7-90.3%) with a specificity of 100% (95% CI 97.5-100%). The Solana assay sensitivity was 94.2% (95% CI 88.9-97.5%) with a specificity of 98.7% (95% CI 95.2-99.8%). Simplexa assay sensitivity was 99.3% (95% CI 96.0-99.9%) with a specificity of 95.3% (95% CI 90.6-98.1%). Aries assay sensitivity was 96.4% (95% CI 91.8-98.8%) with a specificity of 98.0% (95% CI 94.2-99.6%). In summary, all the molecular methods evaluated showed high sensitivity and specificity and were more sensitive than culture.

OBJECTIVES Carbapenem-resistant Pseudomonas aeruginosa are emerging worldwide with increasing reports of carbapenemase-producing isolates. Carbapenem-resistant isolates may also be XDR. This study characterized carbapenem-resistant and XDR P. aeruginosa isolated from patients receiving care at Canadian hospitals from 2007 to 2016. METHODS Antimicrobial susceptibility testing was performed using CLSI broth microdilution methods. PCR was used to detect carbapenemases (GES, KPC, NDM, IMP, VIM, OXA-48) and other resistance markers; specific carbapenemase gene variants were identified by DNA sequencing. Genetic relatedness was assessed by MLST and PFGE. RESULTS From 2007 to 2016, 3864 isolates of P. aeruginosa were collected; 466 (12.1%) isolates were carbapenem resistant. The prevalence of carbapenem-resistant P. aeruginosa reached a peak of 17.3% in 2014. Colistin (94% susceptible) and ceftolozane/tazobactam (92.5%) were the most active agents against carbapenem-resistant P. aeruginosa. XDR P. aeruginosa comprised 4.5% of isolates; they were found to be genetically diverse and remained susceptible to colistin and ceftolozane/tazobactam. Only 4.3% (n = 20) of carbapenem-resistant P. aeruginosa harboured a carbapenemase; most were blaGES-5 (35%, n = 7). Wide genetic diversity was observed among carbapenem-resistant P. aeruginosa with >200 different sequence types identified. CONCLUSIONS Although the prevalence of carbapenem-resistant P. aeruginosa in Canada spiked in 2014 and 2015, carbapenemase-producing P. aeruginosa remain rare with only 20 (4.3%) isolates identified over a 10 year period. Broad genetic diversity was observed among both carbapenem-resistant and XDR phenotypes of P. aeruginosa. Pan-drug-resistant P. aeruginosa have not yet been identified in Canada.

OBJECTIVESWe sought to analyse 10 years of longitudinal surveillance data (2007-16) from the CANWARD study and describe emerging trends in antimicrobial resistance for key bacterial pathogens across Canada.METHODSLongitudinal data from CANWARD study sites that contributed isolates every year from 2007 to 2016 were analysed to identify trends in antimicrobial resistance over time using univariate tests of trend and multivariate regression models to account for the effects of patient demographics.RESULTSStatistically significant increases occurred in the proportion of Escherichia coli isolates resistant to extended-spectrum cephalosporins, amoxicillin/clavulanate, trimethoprim/sulfamethoxazole and ciprofloxacin. Similarly, the proportion of Klebsiella pneumoniae isolates resistant to extended-spectrum cephalosporins, amoxicillin/clavulanate, trimethoprim/sulfamethoxazole, ciprofloxacin and carbapenems increased during the study. The proportion of Enterobacter cloacae isolates resistant to ceftazidime and trimethoprim/sulfamethoxazole increased. The proportion of both ESBL-positive E. coli and K. pneumoniae (including bloodstream isolates) increased significantly between 2007 and 2016. A reduction in the proportion of Pseudomonas aeruginosa that were ciprofloxacin, cefepime, colistin, amikacin and gentamicin resistant and an increase in the proportion of P. aeruginosa isolates non-susceptible to meropenem were observed. The proportion of isolates of Staphylococcus aureus non-susceptible to clarithromycin, clindamycin and trimethoprim/sulfamethoxazole decreased over time while an increase in the proportion of isolates of Streptococcus pneumoniae non-susceptible to clarithromycin, clindamycin and doxycycline was observed.CONCLUSIONSIncreases in Enterobacteriaceae resistance to multiple classes of antimicrobials, increases in ESBL-positive E. coli and K. pneumoniae, and the small but significant increase in carbapenem-resistant K. pneumoniae were the most remarkable changes in antimicrobial resistance observed from 2007 to 2016 in Canada.

OBJECTIVES To assess the prevalence, antimicrobial susceptibilities and molecular characteristics of ESBL-producing Escherichia coli and Klebsiella pneumoniae infecting patients receiving care in Canadian hospitals from January 2007 to December 2016. METHODS Clinical isolates of E. coli (n = 8387) and K. pneumoniae (n = 2623) submitted to CANWARD, an ongoing Canadian national surveillance study, were tested using the CLSI reference broth microdilution method to determine their susceptibility to 15 antimicrobial agents. ESBL-producing E. coli and K. pneumoniae confirmed by the CLSI phenotypic method and putative AmpC-producing E. coli underwent PCR testing and DNA sequencing to identify resistance genes. Annual proportions of isolates harbouring ESBL and AmpC genes were assessed by the Cochran-Armitage test of trend. RESULTS The annual proportion of isolates of E. coli that were ESBL producing increased from 3.4% in 2007 to 11.1% in 2016 (P < 0.0001); >95% of ESBL-producing E. coli were susceptible to amikacin, colistin, ertapenem, meropenem and tigecycline. The proportion of isolates of K. pneumoniae that were ESBL producing increased from 1.3% in 2007 to 9.7% in 2016 (P < 0.0001); >95% of ESBL-producing K. pneumoniae were susceptible to amikacin and meropenem. CTX-M-15 was the predominant genotype in both ESBL-producing E. coli (64.2% of isolates) and ESBL-producing K. pneumoniae (51.0%). The annual proportion of isolates of E. coli that were AmpC producing [annual proportion mean 1.9% (range 0.3%-3.1%)] was unchanged from 2007 to 2016 (P > 0.5). CONCLUSIONS The prevalence of both ESBL-producing E. coli and K. pneumoniae increased significantly in Canada during the study period while the prevalence of AmpC-producing E. coli remained low and stable.

Background: Rapid detection of amoxicillin-susceptible Escherichia coli (ASEC) urinary tract infections (UTIs) could have a significant impact on patient care and improve antibiotic stewardship. This is especially true for infants and children, for whom antibiotic choices are more limited than for adults. Methods: A real-time polymerase chain reaction (PCR) uniplex panel for detection of ASEC using PCR assays for E. coli and five resistance genes ( blaTEM, blaSHV, blaOXA, blaCTX-M, and blaCMY) and an internal control was designed. PCR was then performed directly on pediatric urine samples using an inhibitor-resistant DNA polymerase. The main outcome measure was the performance of the PCR panel (sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV], accuracy) for the detection of ASEC. ASEC samples were defined as those that were E. coli PCR positive and PCR negative for all five resistance genes. PCR results were compared with the reference standard for culture and susceptibility testing. Results: Two hundred and six urine samples with pyuria (>10 white blood cells/high power field) were tested with the PCR panel. Two samples showed PCR inhibition (1%). For ASEC detection, the PCR panel showed a sensitivity of 91.53% (95% CI 81.32% to 97.19%), specificity of 98.21% (95% CI 90.45% to 99.95%), PPV of 98.18% (95% CI 88.54% to 99.74%), NPV of 91.67% (95% CI 82.61% to 96.22%), and accuracy of 94.78% (95% CI 88.99% to 98.06%). Conclusions: This PCR method could potentially enable amoxicillin or ampicillin to be used in a greater proportion of children with E. coli UTIs, improving antibiotic stewardship.

OBJECTIVES The CANWARD surveillance study was established in 2007 to annually assess the in vitro susceptibilities of a variety of antimicrobial agents against bacterial pathogens isolated from patients receiving care in Canadian hospitals. METHODS 42 936 pathogens were received and CLSI broth microdilution testing was performed on 37 355 bacterial isolates. Limited patient demographic data submitted with each isolate were collated and analysed. RESULTS Of the isolates tested, 43.5%, 33.1%, 13.2% and 10.2% were from blood, respiratory, urine and wound specimens, respectively; 29.9%, 24.8%, 19.0%, 18.1% and 8.2% of isolates were from patients in medical wards, emergency rooms, ICUs, hospital clinics and surgical wards. Patient demographics associated with the isolates were: 54.6% male/45.4% female; 13.1% patients aged ≤17 years, 44.3% 18-64 years and 42.7% ≥65 years. The three most common pathogens were Staphylococcus aureus (21.2%, both methicillin-susceptible and MRSA), Escherichia coli (19.6%) and Pseudomonas aeruginosa (9.0%). E. coli were most susceptible to meropenem and tigecycline (99.9%), ertapenem and colistin (99.8%), amikacin (99.7%) and ceftolozane/tazobactam and plazomicin (99.6%). Twenty-three percent of S. aureus were MRSA. MRSA were most susceptible to ceftobiprole, linezolid and telavancin (100%), daptomycin (99.9%), vancomycin (99.8%) and tigecycline (99.2%). P. aeruginosa were most susceptible to ceftolozane/tazobactam (98.3%) and colistin (95.0%). CONCLUSIONS The CANWARD surveillance study has provided 10 years of reference antimicrobial susceptibility testing data on pathogens commonly causing infections in patients attending Canadian hospitals.

Objectives Understanding the epidemiology of invasive Candida infections is essential to patient management decisions and antifungal stewardship practices. This study characterized the species distribution and antifungal susceptibilities of prospectively collected isolates of Candida species causing bloodstream infections (BSIs) in patients admitted to tertiary care hospitals located in 14 cities across 8 of the 10 Canadian provinces between 2011 and 2016. Methods Antifungal susceptibility testing was performed by broth microdilution using CLSI methods, breakpoints and epidemiological cut-off values. DNA sequencing of fks loci was performed on all echinocandin-non-susceptible isolates. Results Candida albicans (49.6%), Candida glabrata (20.8%) and Candida parapsilosis complex (12.0%) were the most common species out of 1882 isolates associated with BSIs. Candida tropicalis (5.2%), Candida krusei (4.3%), Candida dubliniensis (4.1%), Candida lusitaniae (1.4%) and Candida guilliermondii (1.1%) were less frequently isolated. Between 2011 and 2016, the proportion of C. albicans significantly decreased from 60.9% to 42.1% (P < 0.0001) while that of C. glabrata significantly increased from 16.4% to 22.4% (P = 0.023). C. albicans (n = 934), C. glabrata (n = 392) and C. parapsilosis complex (n = 225) exhibited 0.6%, 1.0% and 4.9% resistance to fluconazole and 0.1%, 2.5% and 0% resistance to micafungin, respectively. Mutations in fks hot-spot regions were confirmed in all nine micafungin non-susceptible C. glabrata. Conclusions Antifungal resistance in contemporary isolates of Candida causing BSIs in Canada is uncommon. However, the proportion of C. glabrata isolates has increased and echinocandin resistance in this species has emerged. Ongoing surveillance of local hospital epidemiology and appropriate antifungal stewardship practices are necessary to preserve the utility of available antifungal agents.