New trends in Clostridium difficile virulence and pathogenesis.

The disease spectrum caused by Clostridium difficile infection ranges from antibiotic-associated diarrhoea to life-threatening clinical manifestations such as pseudomembranous colitis. C. difficile infection is precipitated by antimicrobial therapy that causes a disruption of the normal colonic microbiota, predisposing to C. difficile intestinal colonisation. The pathogenicity of C. difficile is mediated by two exotoxins, TcdA and TcdB, both of which damage the human colonic mucosa and are potent cytotoxic enzymes. C. difficile must first be implanted in the gut and attach to epithelial cells, which are protected by a layer of dense mucus. Confirmed and putative accessory virulence factors that could play a role in adherence and intestinal colonisation have been identified and include proteolytic enzymes and adhesins. Recently, the epidemiology of C. difficile infection has radically changed and an increased incidence is associated with outbreaks in North America and Europe. Several reports suggest that disease severity is increasing to include sepsis syndrome and toxin megacolon. Elderly, debilitated patients in hospitals and nursing homes are particularly vulnerable. A hypervirulent, epidemic strain has been associated with the changing epidemiology and severity of disease. Here, we review the characteristics of the epidemic NAP1, PCR ribotype 027 C. difficile strain that could explain its hypervirulence and epidemic spread.

The Lille apathy rating scale (LARS), a new instrument for detecting and quantifying apathy: validation in Parkinson's disease.

BACKGROUND: Apathy is usually defined as reduced interest and participation in various activities. It is a frequent consequence of neurological and psychiatric disorders. Although various scoring methods have been proposed, there is a lack of validated, standardised instruments for detecting apathy and assessing its severity. OBJECTIVE: To develop an apathy rating scale using a structured standardised interview capable of distinguishing between the condition's various features. METHODS: The Lille Apathy Rating Scale (LARS) is based on a structured interview. It includes 33 items, divided into nine domains. Responses are scored on a dichotomous scale. The participants used to validate the scale consisted of 159 patients with probable Parkinson's disease and 58 healthy control subjects. The Marin Apathy Scale, the Montgomery and Asberg Depression Rating Scale, and the Mattis Dementia Rating Scale were also administered. RESULTS: Principal component analysis showed that the LARS probed a single construct which forms the root of an oblique factor structure reflecting four dimensions: intellectual curiosity, self awareness, emotion, and action initiation. The main psychometric properties of the LARS (internal consistency, inter-rater and test-retest reliability) were satisfactory. Concurrent validity was evaluated by reference to the Marin scale and to judgements provided by expert clinicians. CONCLUSIONS: Standard validity indices showed that the LARS is sensitive and capable of distinguishing between apathy and depression. As a screening tool, the scale is able to support dichotomous judgements accurately and, when greater measurement sensitivity is required, also determine the severity of apathy within a four category classification.

Variability in the prevalence of infection and cercarial production in Galba truncatula raised on a high-quality diet.

Two experiments using seven populations of Galba truncatula were carried out to analyse the effect of food quality (cos lettuce only, or cos lettuce+Tetraphyll) on the characteristics of infections: (1) in a single population of G. truncatula infected by one of three digenea (first experiment), and (2) in seven populations of G. truncatula differing in their susceptibility to Fasciola hepatica miracidia (second experiment). In most groups, food quality did not have a significant effect on the survival of snails. The prevalence of infection in five populations was significantly higher in snails raised on lettuce+Tetraphyll (first and second experiments), whereas it was close to those noted in lettuce only-reared groups in the last two populations (second experiment). Despite the higher growth of cercariae-shedding snails when raised on the mixed diet, no significant differences were noted. Significant effects of parasite species (first experiment) and of snail population (second experiment) on the life-spans of cercariae-shedding snails were noted, whereas food quality did not influence this parameter. Except for a single snail population, cercarial production in groups raised on lettuce+Tetraphyll was significantly higher than that in groups on lettuce. The variability noted in the prevalence of snail infections and in the intensity of cercarial shedding might be explained by differences in the susceptibility of snail populations to F. hepatica infections, and/or by the fact that Tetraphyll would not have the same appetency for all populations of G. truncatula.