Risk of occupational blood exposure in a cohort of 24,000 hospital healthcare workers: position and environment analysis over three years.

Early and efficient prevention of occupational blood exposure at hospital requires knowledge of exposures and risks according to staff characteristics. Calculation of annual exposure rates and relative rates from personal and occupational data. The overall annual incidence was 3.5 per 100 workers per year; maximum for nurses and midwives (6.5); minimum for cleaners and paramedics (0.6). Exposures affected mainly nurses (57.81% of accidents, 12.12% of cohort) and occurred mostly in the surgical and the medical departments (26.34 and 25.20% of accidents). Men/women and students/physicians rate differences were not significant. Emergency and intensive care staffs had the highest relative rates (4.27 and 3.05) compared with maintenance staff. Nurses and laboratory staff were more exposed than physicians (3.76 and 2.30 times) were. Our results prompt prevention and training to be precisely focused and efficiently devised.

Substrate-induced production and secretion of cellulases by Clostridium acetobutylicum.

Clostridium acetobutylicum ATCC 824 is a solventogenic bacterium that grows heterotrophically on a variety of carbohydrates, including glucose, cellobiose, xylose, and lichenan, a linear polymer of beta-1,3- and beta-1,4-linked beta-D-glucose units. C. acetobutylicum does not degrade cellulose, although its genome sequence contains several cellulase-encoding genes and a complete cellulosome cluster of cellulosome genes. In the present study, we demonstrate that a low but significant level of induction of cellulase activity occurs during growth on xylose or lichenan. The celF gene, located in the cellulosome-like gene cluster and coding for a unique cellulase that belongs to glycoside hydrolase family 48, was cloned in Escherichia coli, and antibodies were raised against the overproduced CelF protein. A Western blot analysis suggested a possible catabolite repression by glucose or cellobiose and an up-regulation by lichenan or xylose of the extracellular production of CelF by C. acetobutylicum. Possible reasons for the apparent inability of C. acetobutylicum to degrade cellulose are discussed.