Using record linkage to examine testing patterns for respiratory viruses among children born in Western Australia.

Changes in respiratory pathogen testing can affect disease burden estimates. Using linked data, we describe changes in respiratory virus testing among children born in Western Australia in 1996-2012. We extracted data on respiratory specimens from these children from birth to age 9 years. We estimated testing rates by age, year, Aboriginal status and geographical location. Predictors of testing among children hospitalised at least once before their 10th birthday were identified using logistic regression. We compared detection methods for respiratory viruses from nasal/nasopharyngeal (NP) specimens by age and year. Of 83 199 virology testing records in 2000-2012, 80% were nasal/NP specimens. Infants aged <1 month had the highest testing rates. Testing rates in all children increased over the study period with considerable yearly fluctuations. Among hospitalised children, premature children <32 weeks gestation had over three times the odds of being tested (95% CI 3·47-4·13) than those born at term. Testing using molecular methods increased from 5% to 87% over the study period. Proportion of positive samples increased from 36·3% to 44·4% (P < 0·01); this change was greatest in children aged 2-9 years. These findings will assist in interpreting results from future epidemiology studies assessing the pathogen-specific burden of disease.

Eosinopenia as a diagnostic marker of bloodstream infection in hospitalised paediatric and adult patients: a case-control study.

The objective of this study was to assess whether eosinopenia was a reliable diagnostic marker of bloodstream infection in hospitalised adult and paediatric patients. The design was a case-control study, set in a tertiary adult and paediatric hospital. A total of 157 adult and 85 paediatric patients with bloodstream infection ('cases') were compared to 195 and 94 randomly selected adult and paediatric patients who had clinical suspicion of bloodstream infection but with a negative blood culture ('controls') respectively. Patients with haematological or immunosuppressive disease and control patients who were treated with antibiotics within one week prior to the blood culture were excluded. Eosinopenia, or undetectable eosinophil count (<0.01 x 10(9) or <10/mm3), was more common among the cases than the controls (46.5% vs 21.5%, respectively). The specificity of eosinopenia to predict bloodstream infection in adult patients was reasonable (79%, 95% confidence interval [CI] 74 to 82), but its sensitivity was low (47%, 95% CI 41 to 52). The absolute eosinophil count only had a modest ability to discriminate bloodstream infections from controls in adult patients (area under receiver operating characteristic curve 0.349, 95% CI 0.288 to 0.411). Eosinophil counts had very little overall predictive ability (area under receiver operating characteristic curve 0.448, 95% CI 0.363 to 0.533, P=0.237), and the sensitivity (54%, 95% CI 47 to 61) and specificity (56%, 95% CI 49 to 63) of eosinopenia to predict bloodstream infection in paediatric patients were both low. In the multivariate analyses, only C-reactive protein concentrations and neutrophil counts, but not eosinopenia, were significantly associated with the presence of bloodstream infection in both adult and paediatric patients. The presence of eosinopenia can be considered as an inexpensive warning test for bloodstream infection in hospitalised adult patients so that further investigations can be initiated. An absence of eosinopenia is, however not sensitive enough to exclude bloodstream infection. C-reactive protein concentrations and neutrophil counts were both better markers of bloodstream infection than eosinopenia in hospitalised paediatric and adult patients.

Tracking neonatal nosocomial infection: the continuous quality improvement cycle.

Neonatal nosocomial infection (NNI) is a major complication of neonatal care, increasing mortality, morbidity and the costs of healthcare. Management of NNI involves attention to many details of care, creating a culture of change within a neonatal unit and the implementation of a continuous quality improvement cycle. This paper describes the initiation of a quality improvement team (QIT) and the aspects of infection control bundles that have been implemented. The setting was a single large perinatal centre over a seven-year period. Statistical tracking of NNI in exceedingly premature infants was by control charting methodology. A steady and statistically significant decline in NNI rates from 13 to seven episodes per 1000 bed-days (censored to day 35) for infants less than 29 weeks of gestation has been recorded. A multidisciplinary QIT has managed the implementation of measures designed to reduce NNI in the unit. These have included raising awareness of the need for asepsis, improved hand hygiene, increased vigilance in using central lines, monitoring blood culture collection techniques and improving the environment. We believe such measures in conjunction with the positive feedback obtained from charting have been responsible for the steady decline in NNI. This study is one of the first to close the QIT loop and to demonstrate statistical improvement in NNI through the introduction of specific care bundles.

Bacterial contamination in solution aspirated from non-sterile packaged fentanyl ampoules: a laboratory study.

Iatrogenic meningitis is a rare complication of spinal anaesthesia. It is mandatory to use a technique which minimises the risk of introducing bacteria into the subarachnoid space. Currently available fentanyl ampoules require a careful drawing-up technique, as the outside of the ampoule is not sterile and there is potential to contaminate the contents in the drawing-up process. We designed a pilot laboratory study to determine the extent of bacterial contamination of fentanyl solutions drawn up from non-sterile packaged glass fentanyl ampoules using three different methods: aspirating through a 5 microm filter needle only, aspirating through a 5 microm filter needle after swabbing the neck of the ampoule with isopropyl alcohol and aspirating through an antibacterial filter in addition to the 5 microm filter needle. Ten anaesthetists used each method once, in randomised order to draw up solution from three different fentanyl ampoules. Samples underwent bacterial culture in blood agar and enrichment broth for 48 hours. No significant growth was seen in any sample. This pilot study did not identify any bacterial contamination of fentanyl solution irrespective of which of the three methods for aspiration was used.

Best practice guidelines for the operation of a donor human milk bank in an Australian NICU.

Until the establishment of the PREM Bank (Perron Rotary Express Milk Bank) donor human milk banking had not occurred in Australia for the past 20 years. In re-establishing donor human milk banking in Australia, the focus of the PREM Bank has been to develop a formal and consistent approach to safety and quality in processing during the operation of the human milk bank. There is currently no existing legislation in Australia that specifically regulates the operation of donor human milk banks. For this reason the PREM Bank has utilised existing and internationally recognised management practices for managing hazards during food production. These tools (specifically HACCP) have been used to guide the development of Standard Operating Procedures and Good Manufacturing Practice for the screening of donors and processing of donor human milk. Donor screening procedures are consistent with those recommended by other human milk banks operating internationally, and also consistent with the requirements for blood and tissue donation in Australia. Controlled documentation and record keep requirements have also been developed that allow complete traceability from individual donation to individual feed dispensed to recipient and maintain a record of all processing and storage conditions. These operational requirements have been developed to reduce any risk associated with feeding pasteurised donor human milk to hospitalised preterm or ill infants to acceptable levels.

Methicillin-resistant Staphylococcus aureus bacteraemia in Western Australian teaching hospitals, 1997-1999: risk factors, outcomes and implications for management.

The aim of this study was to document the evolution of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia at teaching hospitals in Perth, Western Australia (WA), and determine the risk factors and outcomes of the disease. We performed a retrospective case series analysis of all laboratory-confirmed episodes of S. aureus bacteraemia at Perth teaching hospitals between 1 July 1997 and 30 June 1999 by linking laboratory data with hospitalization data from the state's Hospital Morbidity Data System. Episodes of S. aureus bacteraemia were stratified according to methicillin susceptibility and the relationship between methicillin resistance and key factors or outcomes was determined. Almost 11% of episodes of S. aureus bacteraemia (55/509) were caused by MRSA. On age-adjusted multivariate analysis, Aboriginality (RR 6.71, 95% CI 3.20-14.10, P<0.001), geriatric unit admission (RR 5.74, 95% CI 2.01-16.37, P=0.001), female sex (RR 1.88, 95% CI 1.03-3.42, P=0.04) and healthcare-associated disease (RR 1.93, 95% CI 1.01-3.70, P=0.05) were independently associated with MRSA bacteraemia. Outcomes among those with MRSA bacteraemia included death in 15 patients and re-admission for an MRSA-related complication in five. Empirical use of vancomycin needs consideration in at-risk patients in whom Gram-positive bacteraemia is suspected clinically, with prompt review of therapy once antibiotic susceptibility results are known. The rates of re-admission after discharge for MRSA bacteraemia could be used as a clinical indicator to monitor the quality of care in hospitals.

Bacterial contamination of epidural needles after multiple skin passes.

BACKGROUND: Infection and epidural abscess are important complications of epidural analgesia. Difficult insertion may be associated with an increased risk of bacterial contamination of the epidural needle or catheter. METHODS: Bacterial contamination of epidural needles and trocars after difficult epidural insertion, defined as two or more skin passes, was assessed in 38 obstetric and ten gynaecological patients. RESULTS: There was no bacterial growth on any of the 48 epidural needles or trocars despite the mean (range) insertion time being 20 (10-30) min and the number of insertion attempts being 3 (2-4). CONCLUSIONS: Difficult epidural insertion is not associated with an increased risk of needle contamination and is therefore an unlikely source of epidural infection.

The effect of the biopatch, a chlorhexidine impregnated dressing, on bacterial colonization of epidural catheter exit sites.

We performed a prospective, randomized study in 55 ASA I to 3 women undergoing elective gynaecological surgery followed by postoperative epidural analgesia. We compared the incidence of bacterial colonization at the epidural exit site following catheter removal between a control group and an experimental group who received a chlorhexidine impregnated dressing (Biopatch, Johnson and Johnson, Arlington, TX, U.S.A.). Positive culture results were found in 11 of 27 (40.1%) patients in the control group compared with one of 29 (3.4%) patients whose epidural catheters were dressed with the Biopatch. We concluded that the Biopatch was effective in reducing bacterial colonization of the epidural catheter exit site.

Bacterial [Cu,Zn]-superoxide dismutase: phylogenetically distinct from the eukaryotic enzyme, and not so rare after all!

Copper- and zinc-containing superoxide dismutases ([Cu,Zn]-SODs) are generally considered almost exclusively eukaryotic enzymes, protecting the cytosol and extracellular compartments of higher organisms from damage by oxygen free-radicals. The recent description of a few examples of bacterial forms of the enzyme, located in the periplasm of different Gram-negative micro-organisms, prompted a re-evaluation of this general perception. A PCR-based approach has been developed and used successfully to identify bacterial genes encoding [Cu,Zn]-SOD in a wide range of important human and animal pathogens-members of the Haemophilus, Actinobacillus and Pasteurella (HAP) group, and Neisseria meningitidis. Comparison of [Cu,Zn]-SOD peptide sequences found in Haemophilus ducreyi, Actinobacillus pleuropneumoniae, Actinobacillus actinomycetemcomitans, Pasteurella multocida, and N. meningitidis with previously described bacterial proteins and examples of eukaryotic [Cu,Zn]-SOD has shown that the bacterial proteins constitute a distinct family apparently widely separated in evolutionary terms from the eukaryotic examples. The widespread occurrence of [Cu,Zn]-SOD in the periplasm of bacterial pathogens, appropriately located to dismute exogenously derived superoxide radical anions, suggests that this enzyme may play a role in the interactive biology of organisms with their hosts and so contribute to their capacity to cause disease.