Michael Payne

mcr-1–Positive Colistin-Resistant Escherichia coli in Traveler Returning to Canada from China

To the Editor: A 61-year-old man underwent transurethral prostate resection in Vancouver, British Columbia, in January 2016. On postoperative day 1, he was febrile (39.1°C) and had leukocytosis (12.7 × 109 cells/L). Blood and urine cultures were ordered on postoperative day 2, and ceftriaxone was started. On postoperative day 3, urine culture grew Escherichia coli (>100 million CFU/L). Susceptibility testing (VITEK2, bioMerieux, Quebec, Canada) indicated a possible extended-spectrum β-lactamase producer and showed resistance to ampicillin, cefazolin, ceftriaxone, gentamicin, ciprofloxacin, and trimethoprim/sulfamethoxazole; intermediate resistance to tobramycin; and susceptibility to amoxicillin/clavulanate, piperacillin/tazobactam, ertapenem, meropenem, and nitrofurantoin. Treatment was switched to amoxicillin/clavulanate. The urinary catheter was removed 48 hours later. The patient was discharged on postoperative day 5 and completed 14 days of oral amoxicillin/clavulanate. Blood cultures were negative after 7 days’ incubation.

Antimicrobial stewardship for hospitalized patients with viral respiratory tract infections

Background The purpose of this study was to implement a targeted antimicrobial stewardship intervention for patients with a viral respiratory tract infection. Methods This was a quasi‐experimental before and after audit and feedback intervention of adult inpatients with a positive polymerase chain reaction for a respiratory virus in 2 acute care hospitals in Vancouver, Canada. Audit and feedback was implemented based on 2 criteria: microbiology (no positive bacterial cultures) and chest imaging (absence of pneumonia or consolidation on radiology dictation). A chart review was conducted to assess for days of antibiotics postviral diagnosis. Outcomes including length of stay, intensive care unit admission within 14 days, mechanical ventilation within 14 days, antibiotics prescribed within 14 days, Clostridium difficile infection diagnosed within 30 days, and readmission within 30 days were also reviewed in comparison with the previous year. Results Antimicrobial stewardship recommendations for hospitalized patients with viral respiratory tract infections were accepted for 77% of cases. This targeted approach based on easily assessed parameters translated into a 1.3‐day (95% confidence interval, 0.3‐2.3; P < .01) decrease in mean days of antibiotics postviral diagnosis compared with the previous year without systematic interventions. Compared with the previous year, no differences were identified for adverse outcomes associated with the intervention. Conclusions A targeted antimicrobial stewardship intervention integrating virology testing with the treating physician facilitated a reduction in duration of antibiotic treatment for viral respiratory tract infections.

Transitioning cytomegalovirus viral load testing from a laboratory developed test to the cobas® CMV quantitative nucleic acid assay

Commutability between human cytomegalovirus (CMV) viral load assays (VLA) is poor, despite the development of a WHO CMV International Standard (CMV IS). We evaluated a new CMV VLA, cobas® CMV, as compared to our current laboratory developed CMV VLA (LDT), for clinical use. Both the LDT and cobas® CMV were run in parallel for 109 patient samples. In addition, 104 replicates, over 8 dilutions, of the CMV IS were tested. Conversion factors and correlation between the two assays were calculated. The correlation coefficient between the LDT and cobas® CMV was 0.91 for patient samples. The Bland‐Altman graph displayed a systematic bias of +0.31 log10 for the cobas® CMV as compared to the LDT. The bias was greater for lower CMV viral loads. This increase in CMV viral loads was not seen with testing of the CMV IS dilutions by both the LDT and cobas® CMV. CMV VLA inter‐assay commutability continues to be an issue when switching CMV testing platforms and requires communication between the laboratory and clinicians during the transition period to prevent misinterpretation of results.

Evaluation of the FilmArray Blood Culture Identification Panel compared to direct MALDI-TOF MS identification for rapid identification of pathogens

To improve time to identification of pathogens and detection of resistance genes, we evaluated the BioFire FilmArray Blood Culture Identification Panel (BCID) as compared to: (1) direct MALDI-TOF MS (DM) and (2) standardized culture-based identification (ID) with antibiotic susceptibility testing (AST). BCID gave an accurate identification in 102/112 (91 %) of cases (102/103 for on-panel organisms). DM gave an accurate identification in 91/112 (81 %) of cases, with 13/91 (14 %) requiring repeat testing from the residual pellet. The mean time to an identification result was 2.4 and 2.9 h for BCID and DM, respectively. Standardized ID and AST results were available at a mean time of 26.5 and 33 h, respectively. There were 44 BCID/DM results that had an antimicrobial treatment change made based on rapid identification and resistant gene detection of pathogens. Both BCID and DM are accurate and rapid methods for the identification of new positive blood culture pathogens.

Increase in Hospital Admissions for Severe Influenza A/B among Travelers on Cruise Ships to Alaska, 2015

An increase in hospital admissions for influenza occurred during the summer of 2015 at an acute care facility in Vancouver, British Columbia, Canada. Investigation identified 25 patients with recent history of cruise ship travel to Alaska. All characterized influenza A viruses were A(H3N2). We describe patient treatment regimens and outcomes.