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Biomedical subjects

K Vickery

Publications and source records attributed to K Vickery.

At least 55 records · Page 3Linked to original sources
PubMed1998

Detection of persistent vegetative bacteria and amplified viral nucleic acid from in-use testing of gastrointestinal endoscopes.

Hospital-acquired infection attributed to inadequate decontamination of gastrointestinal endoscopes prompted an in use evaluation of recommended procedures. Specimens were obtained from the internal channels of 123 endoscopes before, during and after decontamination by flushing with saline and brushing with a sterile brush, and examined for vegetative bacteria by broth and plate culture. Four endoscopy units were tested; the chemical disinfectants used were: 2% glutaraldehyde in Centres 1 and 2 (automated) and Centre 3 (manual); peracetic acid in Centre 4 (automated). Samples from patients in Centre 1 with known chronic hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV-1) infection were also examined for viral nucleic acid by ultracentrifugation, nucleic acid extraction, reverse transcription (for RNA) and polymerase chain reaction (PCR). No persistent vegetative bacteria were found following standard manual cleaning and disinfection for 20 min in 2% glutaraldehyde in Centres 2 and 3 (N = 37). At Centre 1, while plate culture yielded no growth, 34% of samples (10/29) grew vegetative bacteria in broth culture after cleaning and disinfection for 20 min in 2% glutaraldehyde. Investigation revealed an error in manual cleaning; no bacteria were detected in 37 samples taken after this was corrected. At Centre 4, despite the use of peracetic acid as a sterilant, three out of 20 (15%) of post decontamination samples grew bacteria; one contained persistent bacteria. HBV and HCV PCR analysis detected viral nucleic acid in three out of four and four out of six samples from viraemic patients undergoing endoscopy in Centre 1 during the period of improper manual washing. After proper cleaning was instituted, samples from nine out of nine HCV viraemic patients were negative. HIV RNA was detected in five of 14 samples taken from endoscopes after use on HIV positive patients but all post decontamination samples were negative. Detection of bacteria in washes from endoscope channels is a useful warning of a breakdown in decontamination practice. Inadequate brushing of internal channels may result in persistent HCV and HBV viral nucleic acid, the significance of which is not clear. These results reinforce the importance of adequate manual cleaning of endoscopes before chemical disinfection.

Bacteria↗
PubMed1997

Antigen-specific blastogenesis assays for duck hepatitis B virus using duck peripheral blood and splenic mononuclear cells.

An antigen-specific lymphoblastogenesis assay for duck hepatitis B surface antigen (DHBsAg) and duck hepatitis B core antigen (DHBcAg) was developed using mononuclear cells from the peripheral blood (PBMC) or spleens (SMC) of immune ducks. Optimal culture conditions for the assay were determined by testing a number of variables, including antigen concentration, cell numbers/well, and the day of harvest. The specificity of the assay was assessed. The assay used 10% pooled duck serum supplement, and 8 x 10(5) cells/well for PBMC or 5 x 10(5) cells/well for SMC. The optimum antigen concentration ranged from 0.01 to 0.1 microgram/ml for both DHBsAg and DHBcAg. Maximum antigen-specific blastogenesis occurred between 4 to 7 days after establishment of the culture. The use of PHA (10 micrograms/ml) mitogenesis could predict the optimal cell numbers/well for antigen-specific blastogenesis. The assay demonstrated specific responses by immune ducks compared with those of unexposed ducklings and adult ducks (for DHBsAg P < 0.001; DHBcAg P < 0.05). For immune ducks, PBMC from all 8 ducks responded to DHBsAg, however, cells from only 4 of 7 immune ducks, responded to DHBcAg. Splenic mononuclear cells from all immune ducks responded to either DHBsAg or DHBcAg or both antigens.

Animals↗