Bacterial testing of platelets - has it prevented transfusion-transmitted bacterial infections in Australia?

BACKGROUND AND OBJECTIVES: Australia introduced bacterial contamination screening (BCS) for platelet components in April 2008. This study presents analysis performed to assess the efficacy of testing. MATERIALS AND METHODS: Seven-day aerobic and anaerobic culture is performed using the BacT/ALERT 3D system. Following an initial machine positive (IMP) flag, all associated components are recalled, and/or clinicians treating already transfused patients are notified. IMPs are categorized as 'machine false positive', 'confirmed positive' or 'indeterminate' depending on culture results of initial and repeat samples. RESULTS: Between 2010 and 2012, 1·1% of platelet donations tested IMP; since 2013, this rate has fallen to 0·6% through improved instrument management, reducing false-positive IMPs but maintaining sensitivity for cultures yielding bacterial growth. On average, 66% of confirmed positive and indeterminate platelet units had been transfused at the time of detection. The majority (95%) of these grew Propionibacterium sp., a slow-growing organism that rarely causes sepsis in the transfusion setting. The incidence of reported transfuion-transmitted bacterial infection (TTBI) has fallen since the introduction of BCS, with a 4·2-fold [0·5, 28·2] lower rate from platelets. CONCLUSION: BCS has been successful in detecting platelet units containing pathogenic bacteria. The incidence of TTBI from platelets has fallen since the introduction of BCS, but the risk has not been eliminated due to rare false-negative results. In the absence of a pathogen inactivation system for red blood cells, BCS provides 'surrogate' testing of red blood cells from which platelets have been manufactured.

Re-evaluating the residual risk of transfusion-transmitted Ross River virus infection.

BACKGROUND AND OBJECTIVES: Ross River virus (RRV) is an enveloped, RNA alphavirus in the same antigenic group as chikungunya virus. Australia records an annual average of 5000 laboratory-confirmed RRV infections. While RRV is currently geographically restricted to the Western Pacific, the capacity of arboviruses for rapid expansion is well established. The first case of RRV transfusion-transmission was recently described prompting a comprehensive risk assessment. MATERIALS AND METHODS: To estimate the RRV residual risk, we applied laboratory-confirmed RRV notifications to two published models. This modelling generated point estimates for the risk of viraemia in the donor population, the risk of collecting a viraemic donation and the predicted number of infected components. RESULTS: The EUFRAT model estimated the risk of infection in donors as one in 95 039 (one in 311 328 to one in 32 399) to one in 14 943 (one in 48 593 to one in 5094). The point estimate for collecting a RRV viraemic donation varied from one in 166 486 (one in 659 078 to one in 49 158) (annualized national risk) to one in 26 117 (one in 103 628 to one in 7729) (area of high transmission). The modelling predicted 8-11 RRV-infected labile blood components issued in Australia during a 1-year period. CONCLUSION: Considering the uncertainty in the modelled estimates, the unknown rate of RRV donor viraemia and the low severity of any recipient RRV infection, additional risk management for RRV in Australia will initially be restricted to strengthening the messaging to donors regarding prompt reporting of any postdonation illnesses.

The residual risk of transfusion-transmitted cytomegalovirus infection associated with leucodepleted blood components.

BACKGROUND AND OBJECTIVES: Cytomegalovirus poses a risk to transfusion safety as its transmission to an immunocompromised recipient may lead to significant clinical sequelae. Once infection is established, it is lifelong and generally asymptomatic. Strategies to reduce the risk of transfusion-transmitted CMV (TT-CMV) include donor serological testing and blood component leucodepletion to deplete the transmissible reservoir. We estimate the residual risk for non-CMV antibody screened, leucodepleted (LD-only) fresh blood components. MATERIALS AND METHODS: We established an approach to estimate the risk of TT-CMV under various scenarios. We estimated the probability of an infectious component, for both red cells and platelets, as a function of the observed WBC filter failure rate and the probability that such a unit was also contaminated with infectious virus. RESULTS: Using this model, the estimated combined residual risk of LD-only red cell and platelet units was very low, 1 in 13 575 000 (95%CI:1 in 1 344 167 000-1 in 1 730 000) as was the individual residual risk estimate for LD-only red cells, 1 in 7 790 000 (95%CI: 1 in 771 307 000-1 in 993 000) and LD-only platelets, where a zero risk was estimated (95%CI: 0-1 in 1 074 000). CONCLUSION: We describe a novel approach to assess the residual risk of LD-only components. This can be applied generally using local data. Our risk estimate for LD-only blood components in Australia is below the threshold of 1 in 1 million, generally considered negligible. This provides a useful indicator of the relative safety of LD-only components to assist clinical decisions when serologically screened inventory is unavailable.

A clinical governance framework for blood services.

BACKGROUND AND OBJECTIVES: The elements of clinical governance, which ensure excellence in clinical care, can be applied to blood services. In this survey, their application in a range of blood providers was gauged, with the aim of identifying best practice and producing a generalizable framework. MATERIALS AND METHODS: The Medical Directors of members of the Alliance of Blood Operators surveyed how different elements of clinical governance operated within their organizations and developed recommendations applicable in the blood service environment. RESULTS: The recommendations that emerged highlighted the importance of an organization's culture, with the delivery of optimal clinical governance being a corporate responsibility. Senior management must agree and promote a set of values to ensure that the system operates with the patient and donor at its heart. All staff should understand how their role fits into the 'journey to the patient', and a culture of openness promoted. Thus, reporting of errors and risks should be actively sought and praised, with penalties applied for concealment. Systems should exist to collect, analyse and escalate clinical outcomes, safety data, clinical risk assessments, incident reports and complaints to inform organizational learning. CONCLUSION: Clinical governance principles from general health care can be applied within blood services to complement good manufacturing practice. This requires leadership, accountability, an open culture and a drive for continuous improvement and excellence in clinical care.

Infectivity of blood components from donors with occult hepatitis B infection - results from an Australian lookback programme.

BACKGROUND AND OBJECTIVES: Previous studies have demonstrated that transfused blood components from donors with occult hepatitis B virus infection (OBI) are potentially infectious. This study reports the results of an Australian lookback programme for the period subsequent to the commencement of individual donation HBV NAT in July 2010 and estimates the HBV transmission rate for components from two categories of donors, confirmed OBI and HBV inconclusive (anti-HBc reactive with non-discriminated NAT result). MATERIALS AND METHODS: Using the results of lookback investigations, we estimated HBV transmission rates by donor category and type of component transfused based on the prevalence of antibodies to HBV core antigen (anti-HBc) in recipients adjusted for the estimated prevalence in the general population. RESULTS: After subtracting the background anti-HBc rate, we derived an adjusted transmission rate (all components) with lower and upper bounds as follows: 0·85% (0·00-2·35%) for OBI donors, 2·83% (1·23-4·33%) for inconclusive donors and 1·81% (0·21-3·31%) for total (OBI and inconclusive) donors. The median adjusted transmission rate for total donors was higher (but not statistically) for plasma (3·01%) than RCCs (2·86%), but there was no evidence of transmission for cryoprecipitate or platelets (0% for both components). CONCLUSION: Our lookback study suggests a low (0·2-3·3%) but measurable rate of HBV transmission in Australia associated with donors with OBI and supports published evidence that at least some blood component types from OBI donors, including a proportion undetectable by ID-NAT can transmit HBV by transfusion.

Compliance with the current 12-month deferral for male-to-male sex in Australia.

BACKGROUND AND OBJECTIVES: In Australia since 2000, donors are deferred for 12 months since last male-to-male sexual contact. There is no estimate of the prevalence of non-compliance (i.e. failure to disclose a risk during the predonation interview which would lead to deferral) with the policy in Australia; however, published studies elsewhere indicate a range of 0·8-2.3% [corrected]. We investigated the rate of, timing and motivation for non-compliance. MATERIALS AND METHODS: A nationally representative sample of donors who had made a recent donation negative for transfusion-transmissible infection testing was surveyed using an anonymous, online instrument. Non-compliance was considered as a 'yes' response to the current screening question. Non-compliers were requested to define the timing of the last sexual contact relevant to their most recent donation. Univariate and multivariate regression analyses were used to define factors associated with non-compliance. RESULTS: Of 14 476 responses from male donors, 34 (0·23%, 95% CI: 0·16-0·33%) were non-compliant of whom 24 (0·17%, 95% CI: 0·11-0·25%) had contact within 6 months of donation. Factors significantly associated with non-compliance included: multiple sexual partners, history of injecting drug use, perception of a lack of privacy during interview and preference for a computer-based questionnaire. CONCLUSION: Our study confirms high compliance (>99·7%) to the 12-month deferral for male-to-male sex in Australia providing reassuring evidence for the efficacy of the screening question. Issues of 'privacy' and 'discomfort' associated with disclosure suggest the use of validated audio computer-assisted structured interview as a possible option for improving compliance with the donor questionnaire.

Ventral acetabular augmentation for management of caudoventral luxation following total hip replacement in dogs.

OBJECTIVE: To report ventral acetabular augmentation with an internal fixator for management of caudoventral luxation following total hip replacement in dogs and to report clinical outcomes. MATERIALS AND METHODS: Clinical records from three UK-based referral hospitals were reviewed retrospectively between 2010 and 2020 to identify dogs with caudoventral hip luxation managed by ventral acetabular augmentation. Hip prosthesis component orientation was radiographically assessed to identify potential risk factors associated with the luxation. Clinical and radiographic assessments were performed at short-term (≤12 weeks) and long-term (>12 months) follow-up and all complications were recorded. A standardised owner telephone questionnaire was used to assess long-term outcomes when a clinical assessment was unavailable. RESULTS: Nine dogs were included. Risk factors contributing to the luxation could not be defined. Implants used included a string-of-pearls plate (6/9), a polyaxial locking plate combined with a polyethylene implant (1/9) or a polyethylene implant alone (2/9). Complications occurred in two of nine dogs, including recurrent luxation and femoral stem loosening; both dogs had received a polyethylene implant alone, of which one received explantation of the hip prosthesis. Median long-term follow-up was 39 months (range 13.5-62). Seven dogs who received a ventral acetabular plate achieved full function of the operated limb and the overall outcome was good for eight dogs. Follow-up radiographs revealed stable hip prostheses in dogs who received a ventral plate, with the longest assessment at 37 months postoperatively. Owner satisfaction was good for all cases. CLINICAL SIGNIFICANCE: Ventral acetabular augmentation can successfully manage caudoventral luxation following total hip replacement in dogs.

Surgical management of superficial digital flexor tendon luxation in dogs: 48 cases (2005-2020).

OBJECTIVES: To report the outcome, frequency of complications and potential prognostic factors associated with surgical repair of superficial digital flexor tendon (SDFT) luxation in dogs. MATERIALS AND METHODS: Medical records from 10 referral hospitals were reviewed retrospectively for cases of SDFT luxation in dogs that underwent surgical stabilisation. Signalment, clinical presentation, diagnostic imaging, surgical method, type and length of post-operative limb immobilisation, nature of and length of exercise restriction, presence of post-operative complications and outcomes were recorded. Data were summarised descriptively and prognostic risk factors assessed for association with surgical outcome using risk ratios. RESULTS: Forty-eight cases were included. A successful surgical outcome was recorded in 35 of 48 (73%) cases. Re-luxation of the SDFT occurred in seven of 48 (15%). Six out of 48 (13%) had a persistent lameness despite a stable non-luxating SDFT. A high frequency of post-operative complications occurred (71%), with the majority resolved medically. The risk of surgical failure was 60% higher (risk ratio 1.6, 95% confidence interval 1.1 to 2.4) where absorbable suture material was used compared to non-absorbable suture material. Surgical failure was more common in cases managed with non-rigid immobilisation post-operatively (57% failure) compared to cases managed with rigid immobilisation (19% failure), although this result was not statistically significant. Limb immobilisation of 6 weeks or longer did not significantly affect surgical outcome, compared to shorter periods of exercise restriction or limb immobilisation. CLINICAL SIGNIFICANCE: A good outcome can be expected following surgical stabilisation of SDFT luxation. The use of non-absorbable suture was associated with a more successful surgical outcome.

A catalyst for transforming health systems and person-centred care: Canadian national position statement on patient-reported outcomes.

Background: Patient-reported outcomes (pros) are essential to capture the patient's perspective and to influence care. Although pros and pro measures are known to have many important benefits, they are not consistently being used and there is there no Canadian pros oversight. The Position Statement presented here is the first step toward supporting the implementation of pros in the Canadian health care setting. Methods: The Canadian pros National Steering Committee drafted position statements, which were submitted for stakeholder feedback before, during, and after the first National Canadian Patient Reported Outcomes (canpros) scientific conference, 14-15 November 2019 in Calgary, Alberta. In addition to the stakeholder feedback cycle, a patient advocate group submitted a section to capture the patient voice. Results: The canpros Position Statement is an outcome of the 2019 canpros scientific conference, with an oncology focus. The Position Statement is categorized into 6 sections covering 4 theme areas: Patient and Families, Health Policy, Clinical Implementation, and Research. The patient voice perfectly mirrors the recommendations that the experts reached by consensus and provides an overriding impetus for the use of pros in health care. Conclusions: Although our vision of pros transforming the health care system to be more patient-centred is still aspirational, the Position Statement presented here takes a first step toward providing recommendations in key areas to align Canadian efforts. The Position Statement is directed toward a health policy audience; future iterations will target other audiences, including researchers, clinicians, and patients. Our intent is that future versions will broaden the focus to include chronic diseases beyond cancer.

Treatment of fractures of the tibial and/or fibular malleoli in 30 cats.

Five cats were treated for a fracture of the medial malleolus, 10 for a fracture of the lateral malleolus and 15 for fractures of both malleoli. Open reduction and internal fixation with Kirschner wires (K-wires) with or without a tension band wire was applied to 26 of the fractures. Unilateral-uniplanar or bilateral-uniplanar transarticular external skeletal fixators were applied to provide coaptation in 19 cases and appeared to be well tolerated. In 24 cases fracture healing was assessed radiographically between four and eight weeks after treatment. In seven cases fracture healing was good, in 12 cases it was reasonable, in four cases it was poor and in one case with two fractures healing was poor in one and reasonable in the other. The 12 fractures treated by open reduction and internal fixation with K-wires and a tension band wire all showed evidence of good or reasonable healing. The nine fractures treated by open reduction and internal fixation with K-wires without a tension band wire showed evidence of good or reasonable healing in six cases and poor healing in three cases. Complications occurred in nine of the cats and included persistent talocrural instability, soft tissue necrosis, implant migration and external fixator pin breakage. Twenty-one of the cats were followed up by telephone questionnaire for between 5.5 and 84 months; the owner satisfaction was excellent in 17 cases, good in two cases, moderate in one case and poor in one case.

Identifying latent tuberculosis in high-risk populations: systematic review and meta-analysis of test accuracy.

BACKGROUND: The relative accuracy of interferon-gamma release assays (IGRAs) and the tuberculin skin test (TST) in identifying latent tuberculosis infection (LTBI) is uncertain.OBJECTIVE: To perform a systematic review and meta-analysis to compare the sensitivity and specificity of IGRAs and TST for the prediction of progression to clinical tuberculosis (TB).METHODS: We searched electronic databases (e.g., MEDLINE and EMBASE) from December 2009 to September 2018 for prospective studies that followed up individuals who had undergone testing with commercial IGRAs and/or TST but had not received treatment based on the test result. The sensitivity and specificity estimates were pooled using a Bayesian bivariate random-effects model.RESULTS: Twenty-five studies, mostly with moderate to high risk of bias and a mean follow-up time ranging from 1 to 5 years were included. TST (10-15 mm) tended to have lower sensitivity and higher specificity than QuantiFERON® Gold In-Tube, T-SPOT®.TB and TST (5 mm). The evidence did not indicate that any test outperformed the others due to wide and overlapping 95% credible intervals.CONCLUSION: The evidence following individuals who had undergone testing for LTBI and had progressed to clinical TB is sparse. We did not find that IGRAs were superior to TST or vice versa; however, as our findings are based on a small number of studies with methodological limitations and great uncertainty around the pooled estimates, the results should be interpreted with caution.

Quantification of local water and biomass in wild type PA01 biofilms by Confocal Raman Microspectroscopy.

Confocal Raman Microspectroscopy (CRM) can be used as a tool for the in situ evaluation of the chemical composition of living, fully submerged, unstained biofilms. In this study the estimation of the local water content in Pseudomonas aeruginosa PA01 biofilms is given as an example. The ratio of the area of the O-H stretching vibration band at 3450 cm(-1), (water), to that of the C-H stretching bands at 2950 cm(-1) (biomass), was used to estimate the relative biofilm water content. The quantification of biofilm water and biomass was based on calibration curves generated from protein solutions. Water/biomass ratios (W:BR) equivalent to that of a 30% (w/v) protein solution were observed within some biofilm colonies.

Right cranial lung lobe torsion after a diaphragmatic rupture repair in a Jack Russell terrier.

A seven-year-old male Jack Russell terrier was presented with a history of coughing, generalised weakness and lethargy 10 days after an abdominal coeliotomy to repair a large diaphragmatic rupture. Thoracic radiographs demonstrated a soft tissue mass in the midcaudal right thoracic cavity. Ultrasonographic studies, bronchoscopy and subsequent exploratory thoracotomy confirmed a diagnosis of a right cranial lung lobe torsion (LLT), with an anomalous caudodorsal displacement of the affected lobe. LLT should be considered as a differential diagnosis for respiratory tract disease following diaphragmatic rupture repair.

Retrograde placement of a novel 3.5 mm titanium interlocking nail for supracondylar and diaphyseal femoral fractures in cats.

Twenty-four simple or comminuted supracondylar and diaphyseal femoral fractures in cats, which had been treated by retrograde insertion of a new 3.5 mm titanium interlocking nail (IN) from the intercondylar notch, were evaluated between June 2000 and October 2004 at the Ecole Nationale Vétérinaire d'Alfort. Patient data (species, breed, weight, and age), fracture characteristics, details of the surgery, post-operative complications and radiographic follow-up were recorded. The mean body weight was 3.75 kg and the cats ranged in age between four and 66 months (mean 29 months). The IN had a diameter of 3.5 mm and a length of 100, 109 or 119 mm, and were all fixed in a static position (two screws in seven cats, three screws in 10 cats and four screws in seven cats). Cerclage wires were used in seven cats and an autogenous bone graft was used in two cats. Screw or nail breakage were not recorded. Nineteen fractures healed without any complications, three cats died during the post-operative period from unknown causes, and two cats showed delayed bone healing. Twenty cats were considered to have an excellent limb function at one month. One cat with a sciatic injury was non-weight bearing for several months. Radiographic signs of degenerative joint disease of the stifle joint were not observed except in the cat with the sciatic nerve injury. The results of this study suggest that this new 3.5 mm titanium IN can be introduced from the intercondylar notch and be used in static fixation mode to stabilize supracondylar and diaphyseal femoral fractures in cats.

Intramural tracheal haematoma causing acute respiratory obstruction in a dog.

Respiratory obstruction resulting from a discrete haematoma within the dorsal tracheal membrane was seen in an 11-year-old neutered female greyhound that had been involved in a fight two days earlier. There was no history or evidence of rodenticide toxicity or other coagulopathy, and it is suggested that the tracheal haematoma resulted from trauma. A right third intercostal thoracotomy was performed and this allowed resection of the haematoma from within the dorsal membrane of the cranial thoracic trachea, relieving the obstruction with no subsequent signs of dyspnoea. Intramural haematoma should be considered as a rare differential diagnosis for dogs presenting with acute respiratory obstruction.

Laryngeal collapse in seven brachycephalic puppies.

OBJECTIVES: To document the histories, clinical findings, and management of seven puppies with laryngeal collapse occurring secondarily to brachycephalic airway syndrome. METHODS: Seven brachycephalic puppies aged between 4.5 and six months underwent surgery for management of brachycephalic airway syndrome following presentation for exercise intolerance and increased respiratory noise and effort. RESULTS: Stenotic nares of varying severity and an elongated soft palate were common to all dogs. All dogs had tracheal hypoplasia and this was severe in four dogs. Laryngeal collapse was present in all dogs. Two dogs had stage I, four dogs stage II, and one dog stage III laryngeal collapse. The dog with stage III laryngeal collapse and one dog with stage II laryngeal collapse died. There was no apparent association between the changes evident on thoracic radiographs or the degree of tracheal hypoplasia and postoperative outcome. CLINICAL SIGNIFICANCE: The development of severe secondary laryngeal changes in dogs aged six months or less supports the suggestion that immature brachycephalic dogs should undergo assessment and, if indicated, surgery as soon as any clinical signs of BAS are apparent.