Staphylococcus aureus with reduced susceptibility to vancomycin isolated from a patient with fatal bacteremia.

A Staphylococcus aureus isolate with reduced susceptibility to vancomycin was obtained from a dialysis patient with a fatal case of bacteremia. Comparison of the isolate with two methicillin-resistant S. aureus (MRSA) isolated obtained from the same patient 4 months earlier suggests that the S. aureus with reduced susceptibility to vancomycin emerged from the MRSA strain with which the patient was infected. Atypical phenotypic characteristics, including weak or negative latex-agglutination test results, weak or negative-slide coagulase test results, heterogeneous morphologic features, slow rate of growth, and vancomycin susceptibility (by disk diffusion test) were observed

Pseudorabies Virus Infection Alters Neuronal Activity and Connectivity In Vitro

Alpha-herpesviruses, including human herpes simplex virus 1 & 2, varicella zoster virus and the swine pseudorabies virus (PRV), infect the peripheral nervous system of their hosts. Symptoms of infection often include itching, numbness, or pain indicative of altered neurological function. To determine if there is an in vitro electrophysiological correlate to these characteristic in vivo symptoms, we infected cultured rat sympathetic neurons with well-characterized strains of PRV known to produce virulent or attenuated symptoms in animals. Whole-cell patch clamp recordings were made at various times after infection. By 8 hours of infection with virulent PRV, action potential (AP) firing rates increased substantially and were accompanied by hyperpolarized resting membrane potentials and spikelet-like events. Coincident with the increase in AP firing rate, adjacent neurons exhibited coupled firing events, first with AP-spikelets and later with near identical resting membrane potentials and AP firing. Small fusion pores between adjacent cell bodies formed early after infection as demonstrated by transfer of the low molecular weight dye, Lucifer Yellow. Later, larger pores formed as demonstrated by transfer of high molecular weight Texas red-dextran conjugates between infected cells. Further evidence for viral-induced fusion pores was obtained by infecting neurons with a viral mutant defective for glycoprotein B, a component of the viral membrane fusion complex. These infected neurons were essentially identical to mock infected neurons: no increased AP firing, no spikelet-like events, and no electrical or dye transfer. Infection with PRV Bartha, an attenuated circuit-tracing strain delayed, but did not eliminate the increased neuronal activity and coupling events. We suggest that formation of fusion pores between infected neurons results in electrical coupling and elevated firing rates, and that these processes may contribute to the altered neural function seen in PRV-infected animals

Fatty acid metabolism (desaturation, elongation and β-oxidation) in rainbow trout fed fish oil- or linseed oil-based diets

In consideration of economical and environmental concerns, fish oil (FO) substitution in aquaculture is the focus of many fish nutritionists. The most stringent drawback of FO replacement in aquafeeds is the consequential modification to the final fatty acid (FA) make-up of the fish fillet.However, it is envisaged that a solution may be achieved through a better understanding of fish FA metabolism. Therefore, the present study investigated the fate of individual dietary FA in rainbow trout (Oncorhynchus mykiss) fed a FO-based diet (rich in 20 : 5n-3) or a linseed oil-based diet (LO; rich in 18 : 3n-3). The study demonstrated that much of the 18 : 3n-3 content from the LO diet was oxidised and, despite the significantly increased accretion of D-6 and D-5 desaturated FA, a 2- and 3-fold reduction in the fish body content of 20 : 5n-3 and 22 : 6n-3, respectively, compared with the FO-fed fish, was recorded. The accretion of longer-chain FA was unaffected by the dietary treatments, while there was a greater net disappearance of FA provided in dietary surplus. SFA and MUFA recorded a net accretion of FA produced ex novo. In the fish fed the FO diet, the majority of dietary 20 : 5n-3 was accumulated (53·8 %), some was oxidised (14·7 %) and a large proportion (31·6 %) was elongated and desaturated up to 22 : 6n-3. In the fish fed the LO diet, the majority of dietary 18 : 3n-3 was accumulated (58·1 %), a large proportion was oxidised (29·5 %) and a limited amount (12·4 %) was bio-converted to longer and more unsaturated homologues