APSIC guide for prevention of catheter associated urinary tract infections (CAUTIs)

BACKGROUND

The Asia Pacific Society of Infection Control launched the APSIC guide for prevention of catheter associated urinary tract infections in July 2022. It aims to highlight practical recommendations in a concise format designed to assist healthcare facilities in the Asia Pacific region to achieve high standards in infection prevention and control practices during the management and care of patients with a urinary catheter.

METHODS

The guidelines were developed by an appointed workgroup comprising experts in the Asia Pacific region, following reviews of previously published guidelines and recommendations relevant to each section.

RESULTS

It recommends that healthcare institutions have a catheter associated urinary tract infection prevention program that includes surveillance and the use of the insertion and maintenance bundles. Implementation of the bundles is best done using a quality improvement approach with a multidisciplinary team.

CONCLUSIONS

Healthcare facilities should aim for excellence in care of patients with urinary catheters. It is recommended that healthcare facilities have a catheter associated urinary tract infection prevention program as part of their Infection Prevention and Control program.

37 RE-AUDIT OF VITAMIN D SUPPLEMENTATION IN FRAIL OLDER ADULTS PRESENTING TO AN IRISH LEVEL 5 EMERGENCY DEPARTMENT

Background

The Department of Health published new guidance in November 2020 “Vitamin D advice for people aged 65 and older” which recommended that all adults ≥65 years should be supplemented with 15micrograms of Vitamin D daily. 55.5% of adults ≥65 years have insufficient/deficient vitamin D levels in winter (TILDA 2020). The Frailty Intervention Team (FIT) assess frail adults ≥65 years in the Emergency Department using medication review and Comprehensive Geriatric Assessment to identify vitamin D supplementation. The audit aim was to determine if compliance with the new guideline improved since the initial audit in January 2021.

Methods

All patients who had a medicine reconciliation completed by the FIT Pharmacist in January 2022 were included in a retrospective audit. Patients were identified from the pharmacist’s worklist. Data was collected from a Hospital Clinical System using a Microsoft Excel®. The data recorded included: Age, Sex, Rockwood Clinical Frailty Score (CFS) and vitamin D supplementation.

Results

The FIT Pharmacist completed 66 medicine reconciliations in January 2022. The mean age (+/-SD) was 82.4 (+/-7.6) years.The male to female ratio was 1:1.75The median CFS was 5 (mildly/moderately frail) with an IQR of 1.

68% (n=45) were prescribed vitamin D. Of those 89% (n=40) were prescribed a supplement containing at least 15micrograms of vitamin D. 32% (n=21) were not prescribed any vitamin D supplementation. 8% (n=5) were prescribed doses lower than 15micrograms of vitamin D.

Conclusion

Compliance with the new guideline was 61% (n=40) in comparison to 65% (n=39) in the initial audit. The results are reflective of adherence to the new guideline in the community. The policy update and education provided post the initial audit has possibly influenced the prescribing of vitamin D in the acute setting which unless patients are re-presenting will not have been captured in the outcome of this re-audit.

306 GERIATRICIAN-LED COMPREHENSIVE GERIATRIC ASSESSMENT IN THE EMERGENCY DEPARTMENT: A COST-EFFECTIVE SERVICE APPROVED BY PATIENTS

Background

Many older people are brought to the Emergency Department (ED) who do not require acute hospital admission but there are risks to these patients if this occurs. The Frailty Intervention Team (FIT) are an interdisciplinary team based in the ED including physiotherapy, occupational therapy, speech and language therapy, dietetics, pharmacy, advanced nurse practitioners, and a geriatric registrar and consultant. They assess frail older patients and suggest alternative care pathways to admission. We aimed to investigate the impact of FIT on admission avoidance, bed days saved and to obtain patient feedback on their experience.

Methods

Routinely collected data from May 2021 to April 2022 was reviewed retrospectively. An anonymous patient feedback questionnaire was posted to 40 patients randomised from the FIT worklist between January to May 2022.

Results

2,025 Comprehensive Geriatric Assessments (CGA) were completed between May 2021 and April 2022. 38% percent of patients were discharged home, 45% of this number had follow-up arranged. 104 patients were transferred directly to an offsite bed, mostly rehabilitation. We estimate we avoided 51 admissions to the acute hospital per month, almost half of these were patients admitted to the hospital and, who we discharged to alternative care pathways or home. The average length of stay in April 2022 was 22 days – by avoiding 615 admissions between May 2021 and April 2022 we have saved 13,530 bed days at an estimated cost saving of almost €11 million. 15 completed questionnaires were returned. 73% were very satisfied with their experience. 87% felt the FIT team helped facilitate their discharge from ED. The main themes identified from open ended questions included thorough assessment, patient centred care and satisfaction with early intervention and discharge.

Conclusion

A Frailty Intervention Team is a cost effective and patient centred way of avoiding unnecessary admissions for older people presenting to the ED.

269 PHARMACIST INTERVENTIONS WITHIN A MULTIDISCIPLINARY CARE TEAM FOR FRAIL OLDER ADULTS PRESENTING TO A LEVEL 4 EMERGENCY DEPARTMENT

Background

Inappropriate polypharmacy and ‘Potentially Inappropriate Prescriptions’ (PIP) are associated with increased morbidity and hospitalisation, in particular among frail older persons. A structured medication review, in conjunction with a Comprehensive Geriatric Assessment (CGA), can address PIP. The aim of the study was to review Frail Intervention Team (FIT) pharmacist interventions for frail, older adults presenting to the Emergency Department (ED) and experiencing medication compliance difficulties, polypharmacy and PIP.

Methods

Patients identified for medication review included those experiencing polypharmacy or medication compliance issues, presenting with a fall, delirium and/or frailty syndromes or complex comorbidities. The medication review process involved completion of medicines reconciliation and medication appropriateness review in accordance with the 7-Steps Medication Review Model (Scottish Government Polypharmacy Model of Care Group, 2018). Pharmacist optimisation recommendations were reviewed by a Consultant Geriatrician or Registrar and discussed with the patient prior to implementation.

Results

The FIT Pharmacist completed medication reviews for 765 patients between May 2021 and April 2022. The mean age (+/-SD) was 83.1 (+/-7.0) years with a median Clinical Frailty Score (CFS) of 5 (mildly/moderately frail). Medication Optimisation recommendations were actioned in 63% (n=483) of patients reviewed. The most commonly encountered PIP’s included: excessive anti-hypertensive/diuretic therapy, long-term acid-suppression therapy, anticholinergics and long-term prophylactic antimicrobials. Prescribing opportunities identified included: bone protection, laxatives and pain management.

Conclusion

FIT pharmacist review, in conjunction with the CGA, led to medication optimisation interventions in the frail older adult cohort presenting to the ED. Future studies should examine the impact of medication review on patient outcomes post-discharge.

Work environment risks for health care workers with cystic fibrosis

In Australia and New Zealand, >50% of people with cystic fibrosis (CF) are adults and many of these people are pursuing vocational training and undertaking paid employment. More than 6% of adults with CF are working in health care. There is limited guidance in literature to support health care workers with CF (HCWcf) in training and in employment to support safe practice and to provide protection for themselves and their patients from the acquisition of health care associated infection. A multidisciplinary team of CF and Infectious Disease Clinicians, Infection Prevention and Control Practitioners, HCWcf, academic experts in medical ethics and representatives from universities, appraised the available evidence on the risk posed to and by HCWcf. Specific recommendations were made for HCWcf, CF health care teams, hospitals and universities to support the safe practice and appropriate support for HCWcf.

APSIC guide for prevention of Central Line Associated Bloodstream Infections (CLABSI)

This document is an executive summary of the APSIC Guide for Prevention of Central Line Associated Bloodstream Infections (CLABSI). It describes key evidence-based care components of the Central Line Insertion and Maintenance Bundles and its implementation using the quality improvement methodology, namely the Plan-Do-Study-Act (PDSA) methodology involving multidisciplinary process and stakeholders. Monitoring of improvement over time with timely feedback to stakeholders is a key component to ensure the success of implementing best practices. A surveillance program is recommended to monitor outcomes and adherence to evidence-based central line insertion and maintenance practices (compliance rate) and identify quality improvement opportunities and strategically targeting interventions for the reduction of CLABSI.

Surgical-Site Infection Rates and Risk Factor Analysis in Coronary Artery Bypass Graft Surgery

Background:

The Victorian Infection Control Surveillance Project (VICSP) is a multicenter collaborative surveillance project established by infection control practitioners. Five public hospitals contributed data for patients undergoing coronary artery bypass graft (CABG) surgery.

Objective:

To determine the aggregate and comparative interhospital surgical-site infection (SSI) rates for patients undergoing CABG surgery and the risk factors for SSI in this patient group.

Method:

Each institution used standardized definitions of SSI, risk adjustment, and reporting methodology according to the National Nosocomial Infections Surveillance System of the Centers for Disease Control and Prevention. Data on potential risk factors were prospectively collected.

Results:

For 4,474 patients undergoing CABG surgery, the aggregate SSI rate was 7.8 infections per 100 procedures (95% confidence interval [CI95], 7.0-8.5), with individual institutions ranging between 4.5 and 10.7 infections per 100 procedures. Multivariate risk factor analysis demonstrated age (odds ratio [OR], 1.02; CI95, 1.01-1.04; P < .001), obesity (OR, 1.8; CI95, 1.4-2.3; P < .001), and diabetes mellitus (OR, 1.6; CI95, 1.2-2.1; P < .001) as independent predictors of SSI. Three hundred thirty-four organisms were isolated from 296 SSIs. Of the total SSIs, methicillin-resistant Staphylococcus aureus was isolated from 32%, methicillin-sensitive S. aureus from 24%, gram-negative bacilli (eg, Enterobacter and Escherichia colt) from 18%, and miscellaneous organisms from the remainder.

Conclusion:

We documented aggregate and comparative SSI rates among five Victorian public hospitals performing CABG surgery and defined specific independent risk factors for SSI. VICSP data offer opportunities for targeted interventions to reduce SSI following cardiac surgery.

Reduction in Hospitalwide Incidence of Infection or Colonization with Methicillin-ResistantStaphylococcus aureusWith Use of Antimicrobial Hand-Hygiene Gel and Statistical Process Control Charts

Objective.

To evaluate the impact of serial interventions on the incidence of methicillin-resistantStaphylococcus aureus(MRSA).

Design.

Longitudinal observational study before and after interventions.

Setting.

The Alfred Hospital is a 350-bed tertiary referral hospital with a 35-bed intensive care unit (ICU).

Interventions.

A series of interventions including the introduction of an antimicrobial hand-hygiene gel to the intensive care unit and a hospitalwide MRSA surveillance feedback program that used statistical process control charts but not active surveillance cultures.

Methods.

Serial interventions were introduced between January 2003 and May 2006. The incidence and rates of new patients colonized or infected with MRSA and episodes of MRSA bacteremia in the intensive care unit and hospitalwide were compared between the preintervention and intervention periods. Segmented regression analysis was used to calculate the percentage reduction in new patients with MRSA and in episodes of MRSA bacteremia hospitalwide in the intervention period.

Results.

The rate of new patients with MRSA in the ICU was 6.7 cases per 100 patient admissions in the intervention period, compared with 9.3 cases per 100 patient admissions in the preintervention period (P= .047). The hospitalwide rate of new patients with MRSA was 1.7 cases per 100 patient admissions in the intervention period, compared with 3.0 cases per 100 patient admissions in the preintervention period (P< .001). By use of segmented regression analysis, the maximum and conservative estimates for percentage reduction in the rate of new patients with MRSA were 79.5% and 42.0%, respectively, and the maximum and conservative estimates for percentage reduction in the rate of episodes of MRSA bacteremia were 87.4% and 39.0%, respectively.

Conclusion.

A sustained reduction in the number of new patients with MRSA colonization or infection has been demonstrated using minimal resources and a limited number of interventions.

Impact of chlorhexidine-impregnated washcloths on reducing incidence of vancomycin-resistant enterococci colonization in hematology-oncology patients

BACKGROUND

Daily skin cleansing with washcloths impregnated with chlorhexidine gluconate (CHG) of patients in intensive care unit is associated with reduction in incidence of vancomycin-resistant Enterococci (VRE) acquisition. This study describes the impact on incidence of VRE colonization after the implementation of daily skin cleansing with 2% CHG-impregnated washcloths in hematology-oncology patients.

METHODS

In this before-and-after study, we compared the incidence rate of VRE colonization during the baseline period (where routine soap-and-water bathing was used) with the intervention period where patients were cleansed with 2% CHG-impregnated washcloths.

RESULTS

Acquisition of VRE decreased from 7.8% in the baseline to 3.8% in the intervention period (relative risk, 0.48, 95% confidence interval [CI], 0.21-1.09; P = .07). The crude relative rate of acquisition during the intervention period compared with the baseline period was 0.53 (95% CI, 0.23-1.23; P = .13). Patients who had been a roommate of a patient subsequently found to have VRE were at a significantly increased risk for acquiring VRE (hazard ratio, 18.8, 95% CI, 5.37-66.15; P < .001). However, patients admitted to the same bed number of previously known VRE-colonized patient were not at increased risk of VRE acquisition (hazard ratio, 0.37, 95% CI, 0.11-1.22; P = .10).

CONCLUSION

We did not observe a statistically significant reduction in the rate of VRE colonization in association with the use of 2% CHG-impregnated washcloths among hematology-oncology patients.

Prevalence and risk factors for VRE colonisation in a tertiary hospital in Melbourne, Australia: a cross sectional study

BACKGROUND

Vancomycin-resistant Enterococcus (VRE) has been established as a significant health-care associated problem since its first isolation in Australia in 1994. In this study, we measured the point prevalence and identified risk factors associated with vanB VRE colonisation in a tertiary care hospital in Melbourne, Australia where VRE has been endemic for 15 years.

METHODS

A hospital-wide point prevalence survey was conducted on October 13, 2008 with colonisation detected using rectal swab culture. Patient's demographic and medical information was collected through a review of medical records. Factors associated with VRE colonisation in univariate analysis were included in multivariate logistic regression model to adjust for confounding.

RESULTS

The prevalence of VRE colonisation on the day of screening was 17.5% (95% CI, 13.7 to 21.9). VRE was detected from patients in each ward with the prevalence ranging from 3% to 29%. Univariate analysis showed the use of any antibiotic, meropenem, ciprofloxacin, diarrhoea and longer length of hospital stay were associated with increased risk of VRE colonisation (p<0.05). However, age, sex, proximity to VRE positive cases, use of other antibiotics including cephalosporins, vancomycin were not associated with increased risk (P>0.05). Multivariate analysis showed the exposure to meropenem (p=0.004), age (≥65 years) (p=0.036) and length of stay ≥7 days (p<0.001) as independent predictors of VRE colonisation.

CONCLUSION

Our study suggests that exposure to antibiotics may have been more important than recent cross transmission for a high prevalence of vanB VRE colonisation at our hospital.

The relationship between conformation and the yield and distribution of lean meat in the carcasses of British pigs, cattle and sheep: A review

Information available on the value of conformation as a predictor of carcass composition in the British livestock population is reviewed, particular reference being made to recent Meat and Livestock Commission (MLC) trials using the visual conformation assessments employed in national carcass classification schemes. In mixed breed populations, the visual conformation assessments are positively related to lean to bone ratio and muscle thickness, although the correlations are generally low. Their relationship with carcass lean content depends on the effectiveness with which variation in fatness is eliminated since fatter carcasses tend to be given higher conformation scores. Conformation provides little information about the proportion of total lean occurring in the higher priced joints. The value of conformation in a mixed breed population depends to an important extent on its ability to identify breed differences in carcass characteristics. Although of some value in this respect, it is less effective than actual breed identification. Within-breed regressions on conformation are generally in the same direction as those in the mixed breed populations, although the precision of prediction is lower. The results indicate that conformation has little practical value as a predictor of carcass composition within breed.

Fatty acid content and composition of UK beef and lamb muscle in relation to production system and implications for human nutrition

Although ruminant meats normally have a low ratio of polyunsaturated fatty acids (PUFA) to saturated fatty acids (P:S ratio), the muscle contains a range of C(20) and C(22) PUFA of both the n-6 and n-3 series of potential significance in human nutrition. However, information on the amounts of these fatty acids in muscle and how they are modified by production system is limited In this study, the content and composition of fatty acids was determined in several muscles from beef steers fed grass (grazed) and bulls fed cereal concentrates. These are the two main types of beef production in the UK and Europe. Muscle fatty acids were also determined in lambs fed grass (grazed on pasture). The total fatty acid content of all muscles studied was less than 35 g kg(-1). The percentages in total fatty acids of all n-3 PUFA were higher in muscles from steers fed grass than from bulls fed concentrates whereas all n-6 PUFA were higher in the latter. The gluteobiceps muscle contained the largest amounts of fatty acids including PUFA and the m. longissimus dorsi the least amounts of PUFA in beef and lamb, and m. longissimus contained the lowest percentages of PUFA. Arachidonic acid was the major fatty acid in the C(20) + C(22) PUFA in beef from both production systems with twice as much in muscles from bulls fed concentrates. The P:S ratios were higher in the latter animals, range 0.21-0.34 compared with 0.08-0.13 in the steers fed grass. However, the n6:n-3 ratio was much less desirable in the bulls, 15.6-20.1 compared with 2.0-2.3 in the steers fed grass. These effects of production system in ruminants are larger than previously reported. Lamb muscle P:S ratios resembled those in grass-fed beef but the n-6:n-3 ratios were lower. The percentage of trans unsaturated 18:1 fatty acids was similar in both cattle production systems but lamb muscles contained twice as much as beef. Although the concentrations of the C(20) and C(22) PUFA are much lower than in fish, maintaining high n-3 levels in ruminant meats through grass feeding may be advantageous in human nutrition since meat is more widely consumed.

A binational cohort study of ventilator-associated pneumonia in Denmark and Australia

The objective was to determine the incidence and prognosis of ventilator-associated pneumonia (VAP) in intensive care units (ICUs) in Melbourne (29-bed ICU), Australia and Aarhus and Aalborg (22-bed unit and 8-bed ICU, respectively), Denmark and to characterize participating ICUs with regard to prevalence of nosocomial type bacterial pathogens, antibiotic resistance and antibiotic consumption. In this prospective cohort study 25 patients in Melbourne and 32 patients in Aarhus + Aalborg had a first episode of VAP. The incidence of VAP per 1000 ventilator d was 6.2 in Melbourne and 9.5 in Aarhus + Aalborg. Case fatality during hospital admission was 28% and 59%, respectively (unadjusted odds ratio (OR) 0.3, 95% confidence interval (CI) 0.1-0.8). OR adjusted for age and APACHE II score was 0.2 (95% CI 0.1-1.0). Nosocomial type pathogens including methicillin resistant Staphylococcus aureus were more prevalent in Melbourne, and antibiotic consumption per VAP patient was 35% higher in Melbourne than in Aarhus + Aalborg. To judge from the present data, there seems to be a complicated interrelationship between prognosis on the 1 hand and antibiotic consumption and resistance on the other. A more favourable prognosis was found in Melbourne, where levels of antibiotic consumption and antimicrobial resistance were higher than in Aarhus + Aalborg.

Daily hazard of acquisition of methicillin-resistant Staphylococcus aureus infection in the intensive care unit

OBJECTIVE

Increasing length of hospital stay is associated with methicillin-resistant Staphylococcus aureus (MRSA) acquisition. The exact risk of becoming colonized with MRSA on a given day has not been clearly elucidated. We determined the hazard of MRSA acquisition in relation to the length of time spent in an intensive care unit in which only standard precautions were used for MRSA-colonized and MRSA-infected patients.

METHODS

This study took place at a tertiary referral hospital intensive care unit in which patients were screened for MRSA at hospital admission, at hospital discharge, and twice weekly during intensive care unit stay. We analyzed the hazard of MRSA acquisition by using a statistical smoothing kernel for hazard with a width of 5 days. Patients were stratified according to age, sex, medical unit, and length of hospital stay.

RESULTS

Of the patients who were at risk of colonization or infection, 12.8% acquired MRSA. The mean length of stay in the intensive care unit was 7.2 days. The daily hazard of acquiring MRSA was less than 1% at admission to the intensive care unit and increased linearly to more than 2% risk per day by day 12, followed by a leveling out of risk.

CONCLUSIONS

The daily hazard of acquiring MRSA is not constant. This has implications for studies that assume a constant hazard in their analysis and should be considered.

Large outbreak of infection and colonization with gram-negative pathogens carrying the metallo- beta -lactamase gene blaIMP-4 at a 320-bed tertiary hospital in Australia

A large outbreak of infection and colonization with multiple genera of gram-negative bacilli carrying the metallo- beta -lactamase gene bla(IMP-4) occurred in a 36-bed intensive care unit at a tertiary hospital in Australia. The organisms emerged rapidly, caused severe infections, and contributed to mortality. Controlling the spread of these organisms remains a challenge for all staff involved.

Rate of nosocomial transmission of vancomycin-resistant enterococci from isolated patients

To evaluate an isolation policy for patients colonised with vancomycin-resistant enterococci (VRE), we instituted active surveillance for transmission to uncolonised patients. Surveillance rectal swabs were taken and pulsed-field gel electrophoresis was performed on positive isolates. VRE transmission with an identical genotype occurred in 5 patients, giving a transmission rate of 3.7 per 1000 patient days, or 1 patient per ward each week. The present study provides a baseline for -assessment of VRE transmission and will be useful in evaluation of the effectiveness of infection control interventions.

Risk factors for acquisition of methicillin-resistant Staphylococcus aureus (MRSA) by trauma patients in the intensive care unit

In a previous study in the intensive care unit (ICU) of the Alfred Hospital, Melbourne, Australia, it was demonstrated that trauma patients were at particular risk of becoming colonized by methicillin-resistant Staphylococcus aureus (MRSA). We examined risk factors for MRSA acquisition in these patients using a cohort study comparing the 31 patients who acquired MRSA with 65 who did not. Data collected included ICU length of stay (LOS), mechanism of trauma, site of injury, type of surgery, trauma severity and antibiotic usage. Odds ratios (OR) were determined and adjusted for LOS. LOS in the ICU was a significant univariate predictor of MRSA acquisition (OR 13.7). When adjusted for LOS, mechanism of trauma (OR 10.4), laparotomy (OR 6.3) and administration of ticarcillin/clavulanic acid (OR 4.5) or glycopeptides (OR 5.9) remained significant. We confirmed our previous finding that LOS was associated with MRSA acquisition. Receipt of antibiotics correlated with reported literature. Novel associations were road trauma as a mechanism and laparotomy.

Acquisition of methicillin-resistant Staphylococcus aureus in a large intensive care unit

OBJECTIVES

To determine the prevalence of MRSA colonization on admission to the ICU and the incidence of MRSA colonization in the ICU.

DESIGN

Prospective cohort study.

SETTING

University hospital.

PARTICIPANTS

Patients admitted to the ICU in 2000-2001.

METHODS

Patients were screened for MRSA with nose, throat, groin, and axilla swabs on admission and discharge. MRSA acquisition was defined as a negative admission screen and a positive discharge screen. Risk factors analyzed included previous wards/current unit, gender, age, and length of stay prior to and in the ICU. Univariate and multivariate analyses were performed using logistic regression.

RESULTS

Of screened patients, 6.8% were MRSA colonized on admission to the ICU. Some patients (11.4%) became newly colonized during their stay in the ICU. Factors that remained significant in the multivariate analysis of MRSA colonization on admission were previous admission to various wards and length of stay prior to ICU admission of more than 3 days. In the multivariate analysis of MRSA acquisition in the ICU, being a trauma patient and length of stay in the ICU greater than 2 days remained significant Thirty-six percent of patients had both admission and discharge swabs taken. This percentage increased in the presence of a supervisory nurse.

CONCLUSION

Significant acquisition of MRSA occurs in the ICU of our hospital, with trauma patients at increased risk. Patients who had been on the cardiothoracic ward prior to the ICU had a lower risk of MRSA colonization on admission. Presence of a supervisory nurse improved compliance with screening

Clinical, microbiological, and economic benefit of a change in antibiotic prophylaxis for cardiac surgery

Vancomycin and rifampicin replaced cephazolin as antibiotic prophylaxis for coronary artery bypass surgery at our institution. Following this intervention, there was a significant decrease (P < .001) in the surgical-site infection rate from 10.5 (95% confidence interval, 8.2 to 13.3) to 4.9 (95% confidence interval, 3.2 to 7.1) infections per 100 procedures. An estimated $576,655 (Australian) was saved between two 12-month periods.

Effluxes of solutes from developing seed coats of Phaseolus vulgaris L. and Vicia faba l.: locating the effect of turgor in a coupled chemiosmotic system

Cells lining the developing seed coats of legumes efflux photosynthates (mostly sucrose) and salts (mostly of potassium) into the apoplast for uptake by the developing embryo. These effluxes increase transiently in response to an increase in turgor in the effluxing cells. Detached coats of developing seed of P. haseolus vulgaris and Vicia faba were used to study the effects of turgor on the rates of efflux, on the membrane potential difference and on the membrane pH difference, using a number of inhibitors and agents which might affect signal cascades involving cytoplasmic calcium concentration. Effluxes were measured by measuring the concentrations of solutes of interest in solution samples placed in halves of detached seed coats, the paired halves serving as control and treated sample where appropriate. It is shown that a number of substances affect sucrose and potassium effluxes differently, and that hypo-osmotic shock depolarizes the efflux cells and acidifies the cytoplasm (in P. vulgaris). It is concluded that sucrose and potassium effluxes, although both are increased by an increase in turgor, are affected by different signal pathways. Further, it is also concluded that the signal that increases the rates of both sucrose efflux (via sucrose-proton antiport) and proton pump acts directly on the antiporter rather than on the pump. There are interesting parallels and contrasts between these processes and those in plants such as the charophyte Lamprothamnium after hypo-osmotic shock.

Risk factors for surgical wound infection and bacteraemia following coronary artery bypass surgery

BACKGROUND

There has been no consensus from previous studies of risk factors for surgical wound infections (SWI) and postoperative bacteraemia for patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

Data on 15 potential risk factors were prospectively collected on all patients undergoing CABG surgery during a 12-month period.

RESULTS

Of 693 patients, 62 developed 65 SWI using the Centres for Disease Control definition: 23 were sternal wound infections and 42 were arm or leg wound infections at the site of conduit harvest. There were 19 episodes of postoperative bacteraemia. Multivariate analysis revealed that: (i) diabetes, obesity and previous cardiovascular procedure were independent predictors of SWI; and (ii) obesity was an independent risk factor for postoperative bacteraemia.

CONCLUSIONS

These findings suggest that improved diabetic control and pre-operative weight reduction may result in a decrease in the incidence of SWI. But further prospective studies need to be undertaken to examine (i) whether the increased SWI risk in diabetes occurs with both insulin- and non-insulin-requiring diabetes, and whether improved peri-operative diabetes control decreases SWI; and (ii) what degree of obesity confers a risk of SWI and postoperative bacteraemia, and whether pre-operative weight reduction, if a realistic strategy in this patient group, results in a decrease in SWI.

Investigation of amine and polyol functionality in extracts of polyurethane wound management dressings using MALDI-MS

Polyurethane (PU) foams used in wound management are produced by a reaction between aromatic diisocyanates and polyether polyols. There is concern that residues of these starting materials, which may contain aromatic amine functionality, may leach from the finished polymer during in vivo applications. Furthermore, oligomers and additives may be leached from the PU system after the polymerization process is complete. Finished polymers have, therefore, been extracted with a range of solvents, such as water, diethyl ether and dilute HCl. The extracts were subjected to MALDI-MS (matrix-assisted laser desorption ionization mass spectrometry) analysis in an attempt to determine the amine and polyol functionality. Direct MALDI-MS analysis of the wound dressing extracts indicated the presence of components based on the polyols [corrected] used in the formulation of the foam. The spacing between the peaks identified the base monomer used in the polyol. MALDI-MS analysis of the fluorescamine derivatives of model amine compounds has demonstrated the anticipated increase in mass (278 for monoamines and 278 and 556 for diamines). Similar results were obtained from the derivatization of model polyols with phenyl isocyanate, where the mass shift (n x 119) was a direct measure of the number of active hydroxyl groups. Fluorescamine labelling of PU foams shows the colour change which could be [corrected] indicative of the presence of an amine, but the subsequent MALDI-MS analysis was unable to demonstrate the anticipated increase in mass.

A cost-analysis of two approaches to infection control in a lung function laboratory

BACKGROUND

The Thoracic Society of Australia and New Zealand (TSANZ) guidelines for infection control in respiratory laboratories are based on a 'Universal Precautions' approach to patient care. This requires that one-way breathing valves, flow sensors, and other items, be cleaned and disinfected between patient use. However, this is impractical in a busy laboratory. The recent introduction of disposable barrier filters may provide a practical solution to this problem, although most consider this approach to be an expensive option.

AIM

To compare the cost of implementing the TSANZ infection control guidelines with the cost of using disposable barrier filters.

METHODS

Costs were based on the standard tests and equipment currently used in the lung function laboratory at The Alfred Hospital. We have assumed that a barrier filter offers the same degree of protection against cross-infection between patients as the TSANZ infection control guidelines. Time and motion studies were performed on the dismantling, cleaning, disinfecting, reassembling and re-calibrating of equipment. Conservative estimates were made as to the frequency of replacing pneumotachographs and rubber mouthpieces based on previous equipment turnover. Labour costs for a scientist to reprocess the equipment was based on $20.86/hour. The cost of employing a casual cleaner at an hourly rate of $14.07 to assist in reprocessing equipment was also investigated. The new high efficiency HyperFilter disposable barrier filter, costing $2.95 was used in this cost-analysis.

RESULTS

The cost of reprocessing equipment required for spirometry alone was $17.58 per test if a scientist reprocesses the equipment, and $15.56 per test if a casual cleaner is employed to assist the scientist in performing these duties. In contrast, using a disposable filter would cost only $2.95 per test. Using a filter was considerably less expensive than following the TSANZ guidelines for all tests and equipment used in this cost-analysis.

CONCLUSIONS

The TSANZ infection control guidelines are expensive and impractical to implement. However, disposable barrier filters provide a practical and inexpensive method of infection control.

Fulminant progression of demyelinating disease after valproate-induced encephalopathy

We report the clinical, radiologic, and pathologic features of a patient who had fulminant demyelinating disease and who experienced acute progression of his disease after an episode of valproate-induced hyperammonemic encephalopathy. The role hyperammonemia played in the progression of the demyelination is uncertain. This case raises concern of a possible risk with the use of valproic acid in the subset of patients with fulminant demyelinating disease.

Improved nonthoracotomy defibrillation based on ventricular fibrillation waveform characteristics

The heart has been shown to be more susceptible to defibrillation at a higher absolute ventricular fibrillation voltage (AVFV) measured on the surface ECG. This study evaluated in a closed-chest canine model (n = 7) the clinical applicability of using a real-time VF waveform analysis system using an electrogram defined between the generator can and an RV endocardial electrode. Under fluoroscopic guidance, superior vena cava and RV spring coil catheter electrodes were inserted through the external jugular vein. A subcutaneous patch was placed on the left chest. A two-parameter tracking algorithm was used to dynamically identify the high AVFV area, and a biphasic shock was triggered synchronously at the next peak. The performance of this new peak shock method (PSM) was compared to the conventional method of shocking at a fixed time in 175 paired trials. Five shocks per voltage and five voltages per animal were randomized between the two methods to permit the generation of sigmoidal dose response curves for the estimation of 50% (E50), 75% (E75), and 100% (E100) success energies. Induction of VF and discharge voltage were kept constant while energy delivered, impedance (R), and AVFV at the point of shock were measured. Energy (8.63 +/- 0.40 vs 8.64 +/- 0.40 J), R (48.60 +/- 0.30 vs 48.59 +/- 0.30 omega), and current (7.50 +/- 0.18 vs 7.51 +/- 0.16 A) were not significantly different between trials for either the conventional or the PSM. The time from the onset of VF until the defibrillation shock was 7.98 +/- 1.44 seconds. Higher overall successes (46.3% vs 33.1%; P < 0.01) and lower E50, E75, and E100 were observed for the PSM. Finally, the significantly higher AVFV (9.12 +/- 0.32 vs 4.73 +/- 0.34 mV; P < 0.0001) with the peak method suggests that the high VF voltage could be detected as it occurred in real-time. The improved defibrillation success supports the use of this method for nonthoracotomy defibrillation.

Investigation of an apparent cluster of Klebsiella pneumoniae bacteremias using random amplified polymorphic DNA analysis

A cluster of bacteremia episodes with Klebsiella pneumoniae was noted in patients in a hematology-oncology ward during a 3-week period. Random amplified polymorphic DNA (RAPD) analysis, a novel technique for generating chromosomal fingerprints from bacterial isolates, was used as an aid to the epidemiological investigation of this cluster. For each of the two patients from whom multiple isolates had been obtained, identical RAPD patterns were observed in the serial isolates, even for a patient where the isolates had different biotypes. Isolates from different patients gave distinct patterns. Random amplified polymorphic DNA was found to be a useful typing technique for this cluster of K pneumonia bacteremias.

Marginal leakage of cast gold crowns luted with zinc phosphate cement: an in vivo study

Marginal gaps of cast restorations are filled with luting agents that are soluble in intraoral fluids. This study investigated the marginal openings in eight extracted teeth with cast crowns that had been intraoral for 20 years or more. These teeth were extracted either because of periodontal disease or to facilitate insertion of a removable partial denture. Initially, the roots of the teeth were sealed with two coats of fingernail polish within 2 mm of the crown-tooth interface. Next, the teeth were immersed in a 0.05% aqueous solution of basic fuchsin die for 24 hours. Finally, each tooth was sectioned at four locations 1 mm apart. At each of these four sections, cement film thickness between tooth and casting, and microleakage were determined. The results of this study showed a mean cement film thickness of 74 microns on the mesial surface and 57 microns on the distal surface. Mean microleakage values were 432 microns on the mesial surface and 274 microns on the distal surface.

Defibrillation success is associated with myocardial organization. Spatial coherence as a new method of quantifying the electrical organization of the heart

The relationship between the degree of electrical organization of ventricular fibrillation (VF) and defibrillation success was investigated in this study using a new technique to quantify organization--spatial coherence. This technique employs the use of the magnitude-squared coherence spectrum to analyze multichannel electrograms obtained during a cardiac mapping study. Magnitude-squared coherence values for all possible pairs of electrograms recorded from an epicardial plaque consisting of 112 electrodes were computed. Average coherence was plotted versus electrode separation distance, and the data were fit with an exponentially decaying curve. Two parameters indicative of myocardial organization were extracted from the curve. The coherence length (d) was defined as the distance (mm) at which the average coherence dropped to a given level, and the coherence strength was defined as the average coherence value at a given distance. Higher values for these parameters were hypothesized to indicate higher levels of organization. The spatial coherence technique was tested previously in a canine study of ventricular fibrillation (VF) and normal sinus rhythm, and the results suggested that spatial coherence parameters may be used to compare cardiac rhythms in terms of their organization. To test the hypothesis that organization is related to defibrillation success, 164 mapping sessions recorded during repeated VF induction and defibrillation trials using a monophasic waveform were performed in a close-chested canine study (n = 9) using a fixed energy and VF duration (10 seconds). Three coherence lengths and five coherence strengths were calculated for each VF episode. Results using a two-way analysis of variance with blocking between dogs showed that all of the coherence length and three of the coherence strength parameters were higher for those VF episodes that were successfully defibrillated than for those that were not (P < .05). Energy delivered and transmyocardial impedance were not significantly different between the groups. The authors conclude (1) the organization of a VF episode, as reflected in the spatial coherence parameters, is related to defibrillation success and may be partially responsible for the probabilistic nature of defibrillation and (2) the spatial coherence technique provides a means of quantifying myocardial electrical organization and is an important experimental tool that may be used to obtain a better understanding of VF and its termination.

Catheter infection. A comparison of two catheter maintenance techniques

Incidence of catheter-related infections was studied using two techniques: changing catheters over a guide-wire or placing a new catheter at a new site every 3 days. Patients were randomized into two groups: Group 1 (new site) and Group 2 (guide-wire). Of the 105 catheterization sites (20 arterial and 85 central lines) in patients of Group 1, none were considered infected (i.e., having 15 or more colonies at the time of semi-quantitative microbiology analysis and clinical signs of infection at the catheter site). Of the 274 catheterization sites (56 arterial and 218 central) of patients of Group 2, eight (2.9%) were infected (chi 2 = 1.89, p greater than 0.05). Colonization (15 or more cultures without clinical signs of infection) occurred in three of 105 (2.9%) and in four of 274 (1.5%) of the catheterization sites of Groups 1 and 2, respectively (chi 2 = 0.23, p greater than 0.05). Study results indicate no significant difference in infection or colonization rates between the two methods of catheter replacement.

Aspergillus clavatus endocarditis involving a normal aortic valve following coronary artery surgery

Aspergillus species causing endocarditis on a native heart valve is a rare occurrence with an exceedingly high mortality. This report describes a 60-year-old man who developed Aspergillus clavatus endocarditis of the aortic valve 18 months after coronary artery bypass surgery. The aortic valve was angiographically normal on cardiac catheterization performed before coronary artery surgery. Despite aortic valve replacement and amphotericin B therapy, the patient died as a result of Aspergillus species aortitis with occlusion of the coronary ostia and bypass grafts. Coronary artery surgery may be complicated by this highly lethal infection, which is difficult to diagnose and treat.

Superoxide dismutase and peroxidase are coordinately regulated in differentiated and transformed tissues of Nicotiana tabacum

We used a series of normal and Agrobacterium-transformed, bacteria-free tobacco tissue cultures which differ in their levels of histodifferentiation to test the relationship of superoxide dismutase, peroxidase, and catalase to oncogenic transformation and differentiation. When compared with normal callus, tumor callus contained reduced levels of both superoxide dismutase and peroxidase, and a reduced number of isozymes of both enzymes. Teratomas characterized by limited but abnormal differentiation showed increases in superoxide-dismutase activity and isozymes, but levels of peroxidase activity lower than those found in normal callus despite an increase in the number of peroxidase isozymes. A similar disparity between low peroxidase activity and high isozyme number in the shoot suggests that there are increased levels of peroxidase inhibitors or of molecules which interfere with the spectrophotometric assay for peroxidase in more differentiated tissues. As judged by the number of isozymes of both superoxide dismutase and peroxidase in each tissue, the following conclusions are warranted: first, tobacco copper/zinc superoxide dismutases and peroxidases are encoded in several duplicated loci which are regulated independently. Second, transformation is associated with a decrease in both the specific activity and isozyme number of superoxide dismutase. Third, the partial release from the total inhibition of expression of differentiated function exhibited by teratoma is associated with an increase in both the activity and isozyme number of superoxide dismutase. Finally, the expression of superoxide dismutase and peroxidase isozymes appears to be coordinated during differentiation in a manner that is consistent with their role in an integrated mechanism for the removal of reduced oxygen species.

The effects of feral goats and sheep on the shrub populations in a semi-arid woodland

Shrubs are increasing in density in extensive areas of semi-arid woodland in Queenstand and New South Wales, reducing their carrying capacity for stock and increasing the difficulty of sheep management. A case study is reported in which an area exclosed from grazing increased from 6000 to 9000 shrubslha in 3 years. Grazing by sheep or goats both reduced the establishment ofAcacia aneura (mulga) and Dodonaea 11iscosa (broad-leaf hopbush) seedlings. Cassia spp. (punty and silver cassia), Eremophila sturtii (turpentine), E. rnitchellii (budda) and Geijera parviflora (wilga) were not reduced. Sheep did not affect mature shrubs to any extent. Extremely heavy goat pressure destroyed several problem shrubs, including Acacia arzeura and Dodorzaea viscosa, and reduced Cassia spp. Mechanical shrub-clearing is often followed by sprouting from the roots of some species. Moderate goat pressure failed to control such sprouts; heavy goat pressure eliminated sprouts from E. rnitchellii and G. parviflora but E. sturtii was not eaten, probably because of its higher oilcontent, and increased to 166% of its preclearing density in two years. Mechanical clearing increased shrub seedling establishment four-fold. Future increases in shrub density may be expected in semi-arid woodland communities and goats do not offer an answer to the problem because they are selective between species and because managerially significant reductions in shrub populations can only be achieved at extremely high stocking pressures. The expense of fencing for such a treatment, the damage to the herb layer and the lack of a post treatment management, that would prevent the replacement of palatable shrubs by unpalatable ones, makes it an unsuitable technique for extensively grazed properties.

Hypophosphatasia. Review of 24 cases

Radiographic analysis of 24 cases of hypophosphatasia (H) from 9 Paediatric Centres was performed. 3 cases were of neonatal (lethal), 18 cases of infantile (severe) and 3 cases of late (benign) type. Some of the patients were in reality borderline cases between these groups. In the authors' material all the patients showed radiographic signs of the disease. These were divided into diagnostic, characteristic and suggestive features. All of the patients had in common generalised (usually irregular) osteoporosis, generalised (usually irregular) metaphyseal changes, craniostenosis (13 of 18 infantile cases) or widened cranial sutures and ofter bowing of the long bones. Besides the well know radiographic features of hypophosphatasia some less well known, rare or 'new' ones such as, 1. spurs of the long bones (Bowdler sign), 2. distal femoral central metaphyseal defects and epiphyseal defects, 3. S-like deformities of the tibiae, 4. abnormal shape of the distal phalanges of the fingers, 5. multiple rib fractures and slender bones, 6. wedging of the lower thoracic and upper lumbar vertebrae, 7. partial premature fusion of the epiphyses, 8. nephrocalcinosis, 9. loss of lamina dura around the teeth, 10. variation in radiographic appearances of a pair of siblings with lethal form, and, 11. rapid changes in roentgen appearances. are discussed. In two of our patients (siblings) phosphoethanolamine was undetectable in the urine. The authors doubt if a normal skeletal survey may be present at any stage in any of the three major types of hypophosphatasia.