Facile hyperpolarization chemistry for molecular imaging and metabolic tracking of [1-13C]pyruvate in vivo.

Hyperpolarization chemistry based on reversible exchange of parahydrogen, also known as Signal Amplification By Reversible Exchange (SABRE), is a particularly simple approach to attain high levels of nuclear spin hyperpolarization, which can enhance NMR and MRI signals by many orders of magnitude. SABRE has received significant attention in the scientific community since its inception because of its relative experimental simplicity and its broad applicability to a wide range of molecules, however in vivo detection of molecular probes hyperpolarized by SABRE has remained elusive. Here we describe a first demonstration of SABRE-hyperpolarized contrast detected in vivo, specifically using hyperpolarized [1-13C]pyruvate. Biocompatible formulations of hyperpolarized [1-13C]pyruvate in, both, methanol-water mixtures, and ethanol-water mixtures followed by dilution with saline and catalyst filtration were prepared and injected into healthy Sprague Dawley and Wistar rats. Effective hyperpolarization-catalyst removal was performed with silica filters without major losses in hyperpolarization. Metabolic conversion of pyruvate to lactate, alanine, and bicarbonate was detected in vivo. Pyruvate-hydrate was also observed as minor byproduct. Measurements were performed on the liver and kidney at 4.7 T via time-resolved spectroscopy and chemical-shift-resolved MRI. In addition, whole-body metabolic measurements were obtained using a cryogen-free 1.5 T MRI system, illustrating the utility of combining lower-cost MRI systems with simple, low-cost hyperpolarization chemistry to develop safe, and scalable molecular imaging.

Bloodstream infection with extended-spectrum beta-lactamase-producing Enterobacteriaceae at a tertiary care hospital in New Zealand: risk factors and outcomes.

OBJECTIVES: To define local risk factors and outcomes for bacteremia with extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) at a tertiary hospital in New Zealand. METHODS: Patients with ESBL-E bacteremia were compared to matched control patients with non-ESBL-producing Enterobacteriaceae bacteremia. Patients were matched by onset of bacteremia (community vs. hospital), site of blood culture collection (peripheral vs. via central line), and infecting organism species. RESULTS: Forty-four cases with matched controls were included. Eight- and 30-day mortality was higher in cases than controls (27% vs. 7%; p=0.011 and 34% vs. 11%, p=0.011). Twenty-one cases (48%) were community-onset. Community-onset cases were associated with urinary tract infection, whereas hospital-onset cases were associated with central line infection, intensive care admission, and Enterobacter cloacae. Independent risk factors for ESBL-E bacteremia were fluoroquinolone exposure (odds ratio (OR) 6.56, 95% confidence interval (CI) 1.79-24), first-generation cephalosporin exposure (OR 12.3, 95% CI 1.01-148), and previously-known colonization with ESBL-E (OR 46.2, 95% CI 3.45-619). CONCLUSIONS: The association with fluoroquinolone exposure suggests that measures to reduce unnecessary use may be an effective preventative strategy. Known colonization with ESBL-E is a strong risk factor for ESBL-E bacteremia, and colonization status should be taken into consideration when choosing empirical therapy.

A case of tricuspid valve endocarditis due to Burkholderia cepacia complex.

Burkholderia cepacia complex organisms are environmental Gram-negative bacteria which rarely cause disease in otherwise immunocompetent individuals. We describe a case of tricuspid valve endocarditis secondary to B. cepacia complex in an injecting intravenous drug user in Auckland, New Zealand.

First case of Mycobacterium heckeshornense lymphadenitis.

Mycobacterium heckeshornense is a slow-growing nontuberculous mycobacterium first characterized in 2000. It is reported to cause lung disease and tenosynovitis. We report a case of isolated massive axillary lymphadenopathy in an elderly woman, where histology showed necrotizing granulomata and M. heckeshornense was isolated as the causative organism.

Community-onset genitourinary tract infection due to CTX-M-15-Producing Escherichia coli among travelers to the Indian subcontinent in New Zealand.

A series of patients are described who presented to a New Zealand hospital with genitourinary tract infection due to CTX-M-15-producing Escherichia coli. All had a history of travel to the Indian subcontinent and lacked traditional risk factors for urinary tract infection due to a multidrug-resistant organism.