Methicillin-resistant Staphylococcus aureus in orthopaedic surgery.

Methicillin-resistant Staphylococcus aureus (MRSA) has become a ubiquitous bacterium in both the hospital and community setting. There are two major subclassifications of MRSA, community-acquired and healthcare-acquired, each with differing pathogenicity and management. MRSA is increasingly responsible for infections in otherwise healthy, active adults. Local outbreaks affect both professional and amateur athletes and there is increasing public awareness of the issue. Health-acquired MRSA has major cost and outcome implications for patients and hospitals. The increasing prevalence and severity of MRSA means that the orthopaedic community should have a basic knowledge of the bacterium, its presentation and options for treatment. This paper examines the evolution of MRSA, analyses the spectrum of diseases produced by this bacterium and presents current prevention and treatment strategies for orthopaedic infections from MRSA.

Validation of a high-performance liquid chromatographic assay for the quantification of adenovirus type 5 particles.

An anion-exchange-high-performance liquid chromatography (AE-HPLC) method for the quantification of adenovirus type 5 (Ad5) total particles was validated according to performance criteria of precision, specificity, linearity of calibration and range, limit of detection, limit of quantification, accuracy and recovery. The viral particles were detected by absorbance at 260 nm using photodiode array detector (PDA). Cesium chloride (CsCl) purified Ad5 and lysate samples were used for the validation of the method. Relative standard deviations (RSDs) for the inter-day, intra-day precision and reproducibility for both the lysate and the Ad5 standard were less than 10 and 2% for the peak area and retention time, respectively. The method was specific for Ad5 which was eluted at 8.0 min. The presence of DNA does not affect the recovery of Ad5 particles for accurate quantification. Based on the error in prediction to be less than 10%, the working range was established between 2 x 10(10) and 7 x 10(10) VP/ml with correlation coefficient of 0.99975, standard deviation of 6.14 x 10(9) VP/ml and a slope of 3.04 x 10(5) VP/ml. The recovery of the method varied between 88 and 106% in all of the lysate samples investigated which is statistically similar to 100% recovery at 95% confidence interval.

Beta-mannanase of Streptomyces lividans 66: cloning and DNA sequence of the manA gene and characterization of the enzyme.

The gene coding for a beta-mannanase was cloned homologously from Streptomyces lividans and its DNA sequence was determined. The fully secreted enzyme was isolated and purified from culture filtrates of the hyperproducing clone S. lividans IAF36 grown in mineral salt media containing galactomannan as the main carbon source. It had a molecular mass of 36 kDa and a specific activity of 876 i.u./mg of protein. Under the assay conditions used, the optimal enzyme activity was obtained at 58 degrees C and a pH of 6.8. The pI was 3.5. The kinetic constants of this mannanase determined with galactomannan as substrate were a Vmax. of 205 i.u./mg of enzyme and a Km of 0.77 mg/ml. Data from SDS/PAGE and Western blotting show that the cloned enzyme was identical to that of the wild-type strain.