Oral beta-lactam step down in bacteremic E. coli urinary tract infections.

BACKGROUND: Literature is scarce regarding oral step down to beta-lactams in bacteremic urinary tract infections. Oral fluoroquinolones are an accepted and common step down for bacteremic urinary tract infections; however, their use is associated with mounting safety concerns. We compared clinical cure in patients with E. coli bacteremic urinary tract infections who were stepped down to oral beta-lactams compared to oral fluoroquinolones. METHODS: This multicentre retrospective cohort study included patients with first positive concurrent urine and blood cultures from January 2016 to December 2016. Patients were included if they received empiric intravenous beta-lactam therapy with step down to either oral beta-lactam or fluoroquinolone for treatment completion. The primary outcome was clinical cure. Secondary outcomes were length of hospitalization, all-cause mortality and C. difficile infection. Multivariate analysis and propensity score were used to control for confounding. RESULTS: A total of 207 patients were identified with bacteremic E.coli urinary tract infections. Clinical cure was achieved in 72/77 (94%) in the oral beta-lactam group versus 127/130 (98%) in the oral fluoroquinolone group (absolute difference - 4.2, 95% confidence interval [CI] -10.3 to 1.9%, p = 0.13). The adjusted odds ratio (OR) for clinical cure with oral beta-lactams was 0.31 (95% CI 0.05-1.90, p = 0.21); propensity score adjusted analysis showed a similar result. There was no statistically significant difference in secondary outcomes. CONCLUSIONS: Oral beta-lactams appear to be a safe and effective step down option in bacteremic E. coli urinary tract infections compared to oral fluoroquinolones.

Emergence and characterization of Neisseria gonorrhoeae isolates with decreased susceptibilities to ceftriaxone and cefixime in Canada: 2001-2010.

BACKGROUND: Globally, Neisseria gonorrhoeae antimicrobial resistance has been increasing, and in particular, reports of isolates with reduced susceptibility to third-generation cephalosporins have surfaced. We examined the phenotypic and genetic characteristics of 155 N. gonorrhoeae isolates with decreased susceptibilities to third-generation cephalosporins isolated in Canada between 2001 and mid-2010. METHODS: Minimum inhibitory concentrations (MICs) were determined by agar dilution on N. gonorrhoeae isolates, and those displaying elevated MICs to cefixime (MIC = 0.25 µg/mL and 0.5 µg/mL) and ceftriaxone (MIC = 0.125 µg/mL and 0.25 µg/mL) were examined using N. gonorrhoeae multiantigen sequence typing (NG-MAST) and sequencing of resistance determinants associated with decreased cephalosporin susceptibilities (penA, mtrR, ponA, porB1b (penB alteration). RESULTS: Between 2001 and 2010, there has been a shift in the modal MICs from 0.016 to 0.125 µg/mL for cefixime and from 0.016 to 0.063 µg/mL for ceftriaxone. Thirty-seven different sequence types (STs) were identified among the isolates using N. gonorrhoeae multiantigen sequence typing; ST3158, ST225, and ST1407 were most prevalent at 25.9%, 19.4%, and 14.8%, respectively. The penA mosaic was present in 60% of the isolates, with the most common penA mosaic types XXXII and X identified at 51.0% and 7.7%, respectively, whereas the nonmosaic penA type XII was identified in 36.8% of the isolates. CONCLUSIONS: In Canada, N. gonorrhoeae isolates with decreased susceptibilities to third-generation cephalosporins have increased over the years. The alterations in penA, mtrR, and porB1b (penB alteration) are important determinants identified in these isolates. The most common STs identified among these Canadian isolates have also been reported worldwide.

Canada's first case of a multidrug-resistant Corynebacterium diphtheriae strain, isolated from a skin abscess.

A toxigenic Corynebacterium diphtheriae biovar mitis sequence type 136 (ST136) strain was recovered from a toe infection of an unvaccinated patient recently returned from India. The isolate was resistant to clindamycin, erythromycin (ermX positive), tetracycline, and trimethoprim-sulfamethoxazole, intermediate to ceftriaxone and cefotaxime, and had high MICs for telithromycin and chloramphenicol but was sensitive to other drugs.