Are surgical scrubbing and pre-operative disinfection of the skin in orthopaedic surgery reliable?

This study attempts to establish the actual effectiveness of pre-surgical disinfection of the patient and surgeon's hands. We evaluated bacterial density and composition on the skin of 15 patients undergoing knee arthroscopy and the left hand of two surgeons after standard disinfection with povidone-iodine. Three samples were taken after the first 6-min scrub in the first surgical operation from the periungual space of the 1 degrees finger, from the interdigital space between the 2 degrees and 3 degrees fingers and from the transverse palmar crest of the left hand of two surgeons for seven consecutive surgical sessions, for a total of 42 samples, and two samples from the pre-patellar skin and from the popliteal skin of 15 patients undergoing knee arthroscopy, for a total of 30 samples. Pre-surgical handwashing and disinfection procedures were identical in each case. Pre-surgical disinfection of the patient's skin with povidone-iodine was shown to be completely effective, with 100% of samples negative. Samples taken from the interdigital space and the palmar crest (100% of samples negative) demonstrated the efficacy of disinfection of the surgeon's hands with povidone-iodine, while the periungual space was contaminated in 50% of the samples. The bacterial strains isolated belong to the staphylococcus genus in 100% of the cases, with pathogenic strains in 29.6% of the cases. Standard pre-surgical disinfection of skin in areas easily accessible to the disinfectant is sufficient in itself to guarantee thorough sanitization. Standard scrubbing of the surgeon's hands is insufficient in eliminating bacterial contamination, including pathogenic germs, in the periungual space, where it is probably difficult for the disinfectant to come into contact with the skin.

The outcome of acute hepatitis C predicted by the evolution of the viral quasispecies.

The mechanisms by which hepatitis C virus (HCV) induces chronic infection in the vast majority of infected individuals are unknown. Sequences within the HCV E1 and E2 envelope genes were analyzed during the acute phase of hepatitis C in 12 patients with different clinical outcomes. Acute resolving hepatitis was associated with relative evolutionary stasis of the heterogeneous viral population (quasispecies), whereas progressing hepatitis correlated with genetic evolution of HCV. Consistent with the hypothesis of selective pressure by the host immune system, the sequence changes occurred almost exclusively within the hypervariable region 1 of the E2 gene and were temporally correlated with antibody seroconversion. These data indicate that the evolutionary dynamics of the HCV quasispecies during the acute phase of hepatitis C predict whether the infection will resolve or become chronic.

Experimental transmission of hepatitis C virus-associated fulminant hepatitis to a chimpanzee.

Hepatitis C virus (HCV) was transmitted from a patient with fulminant hepatitis C to a chimpanzee. The patient had developed two episodes of fulminant hepatitis C, each occurring after a separate liver transplantation. Serial serum and liver samples from the patient and the chimpanzee were analyzed for HCV replication, genotype, quasispecies heterogeneity, and antibodies. In the patient, the levels of HCV replication in serum and liver correlated with the degree of hepatocellular necrosis and the clinical expression of fulminant hepatitis. The same HCV strain, genotype 1a, was recovered from both episodes of fulminant hepatitis. An unusually severe acute hepatitis was also observed in the chimpanzee. The viruses recovered from the patient and the chimpanzee were almost identical and displayed relatively little quasispecies heterogeneity. Thus, the same HCV strain induced two episodes of fulminant hepatitis in a single patient and severe hepatitis in a chimpanzee, suggesting that the pathogenicity or virulence of a specific HCV strain may be important in the pathogenesis of fulminant hepatitis C.