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Severe acute respiratory syndrome (SARS) is an emerging infectious disease. After the appearance of an index patient in Hong Kong in February 2003, SARS outbreaks occurred rapidly in hospitals and spread to the community. The aim of this retrospective study is to evaluate the effectiveness of a triage policy and risk-stratified infection control measures in preventing nosocomial SARS infection among paediatric healthcare workers (HCWs) at the Prince of Wales Hospital, a general hospital to which children with SARS are referred in Hong Kong. The acute paediatric wards were stratified into three areas: (1) ultra high-risk area, (2) high-risk area and (3) moderate-risk area according to different risk levels of nosocomial SARS transmission. The implementation of different levels of infection control precautions was guided by this risk stratification strategy. Between 13 March and 23 June, 38 patients with probable and suspected SARS, 90 patients with non-SARS pneumonia, and 510 patients without pneumonia were admitted into our unit. All probable SARS cases were isolated in negative-pressure rooms. Twenty-six HCWs worked in the ultra high-risk area caring for SARS patients and 88 HCWs managed non-SARS patients in other ward areas. None of the HCWs developed clinical features suggestive of SARS. In addition, there was no nosocomial spread of SARS-associated coronavirus to other patients or visitors during this period. In conclusion, stringent infection control precautions, appropriate triage and prompt isolation of potential SARS patients may have contributed to a lack of nosocomial spread and HCW acquisition of SARS in our unit.

Twelve research groups participated in the ISOBM TD-3 Workshop in which the reactivity and specificity of 83 antibodies against prostate-specific antigen (PSA) were investigated. Using a variety of techniques including cross-inhibition assays, Western blotting, BIAcore, immunoradiometric assays and immunohistochemistry, the antibodies were categorized into six major groups which formed the basis for mapping onto two- and three-dimensional (2-D and 3-D) models of PSA. The overall findings of the TD-3 Workshop are summarized in this report. In agreement with all participating groups, three main antigenic domains were identified: free PSA-specific epitopes located in or close to amino acids 86-91; discontinuous epitopes specific for PSA without human kallikrein (hK2) cross-reactivity located at or close to amino acids 158-163; and continuous or linear epitopes shared between PSA and hK2 located close to amino acids 3-11. In addition, several minor and partly overlapping domains were also identified. Clearly, the characterization of antibodies from this workshop and the location of their epitopes on the 3-D model of PSA illustrate the importance of selecting appropriate antibody pairs for use in immunoassays. It is hoped that these findings and the epitope nomenclature described in this TD-3 Workshop are used as a standard for future evaluation of anti-PSA antibodies.

Epitope mapping analysis was performed on 53 antibodies submitted to the ISOBM TD-3 PSA Workshop. Western blotting and N-terminal amino acid sequencing, using both native and recombinant human prostate-specific antigen (rPSA), identified four different epitope groups for native PSA. Under reducing conditions native PSA was not recognized by 18/53 antibodies suggesting they reacted with conformation-dependent epitopes. Nine other antibodies reacted with a rPSA polypeptide doublet of 34-35 kD corresponding to different rPSA glycoforms. From sequence mapping studies 22/53 antibodies bound epitopes within amino acid residues 25-85, 3/53 antibodies bound to epitopes within residues 86-220, while 10/53 antibodies bound epitopes within residues 221-261. These results indicate that there are multiple immunogenic epitopes localized on the PSA molecule.

We describe an exposure of varicella zoster virus in our neonatal intensive-care unit and the emergency procedures instituted to prevent an outbreak. Fifty-seven infants and 129 staff members were exposed but none developed chickenpox. The measures included rapid identification of varicella antibody status in all neonates and those staff members with uncertain history of varicella infection; cohorting of exposed infants according to immune status; and prompt administration of varicella zoster immunoglobulin to susceptible patients. The recommendation of the American Academy of Pediatrics did not accurately predict the immune status of preterm infants, as only one of the eight susceptible infants would have qualified for immunoglobulin prophylaxis if their guidelines had been followed. Mass screening of all exposed infants using the varicella zoster enzyme linked immunosorbent assay (ELISA) test was the only reliable means of determining the immune status. Of the four risk factors evaluated for the prediction of antibody status: gestational age, postnatal age, birthweight and episodes of blood transfusion, only postnatal age was found to independently predict the immune status of our patients. Because varicella zoster susceptible staff members are difficult to identify on the basis of history, we suggest that prospective screening of staff in high-risk units be undertaken and vaccination with live varicella vaccine be offered to susceptibles.

A pair of preterm twins developed fatal necrotizing enterocolitis (NEC) in association with Staphylococcus epidermidis septicaemia after receiving contaminated expressed breast milk (EBM). S. epidermidis NEC can be associated with severe bowel inflammation, high morbidity and mortality. Breast milk is the most suitable nutrient for preterm infants but EBM should undergo regular screening for bacterial overgrowth. We urge caution before administering EBM found to be heavily contaminated with S. epidermidis to preterm infants.

We describe an outbreak of Gram-negative septicaemia due to a rare, non-fermenting, aerobic organism, Acinetobacter calcoaceticus var. lwoffi. The outbreak occurred on a neonatal unit and was confined to babies who were receiving parenteral nutrition. Seven babies developed septicaemia within 24 hours. The source of the outbreak was never firmly established, but contamination of the parenteral nutrition fluid was considered most likely. All 7 babies recovered uneventfully after a week's course of intravenous ceftazidime. Thrombocytopenia was an unexpected feature of this infection.

The attitudes of managers and union officials to employee participation appear to have mellowed over time, although it is possible that forces favouring participation have emerged that only produce an impression of mellowing. Recent studies do, however, seem to indicate that there is a growing acceptance of the broad concept of participation by both managers and union officials. The Commonwealth Government's Policy on Employee Participation is analysed in the light of the recent evidence and, while the Policy promises very little, it is possible that it could provide the basis for substantial change. The present study attempts to analyse the responses of managers and union officials to 22 state ments abstracted from the Policy. The results indicate a generally favourable response although there is substantial divergence between the two groups over a number of important issues. The area of most concern is in the practical application of employee participation programmes where managers appear to be in conflict with the Policy while union officials do not. The conclusion is that the overall acceptance of the Policy has been achieved at the expense of the role of the government and, because of this, rhetoric about employee par ticipation may, in the future, play a larger role than the implementation of definite programmes designed to put the concepts into practice.