rapid-identification-gram-negative-bacteria-from-blood-culture-broth

Rapid Identification of Gram Negative Bacteria from Blood Culture Broth Using MALDI-TOF Mass Spectrometry

An important role of the clinical microbiology laboratory is to provide rapid identification of bacteria causing bloodstream infection. Traditional ...

Westmead hospital

Bone button anchors constructed from allograft bone were investigated as an alternative for rotator cuff repair. Bone button anchors were used in 59 consecutive procedures after mechanical pullout strength and cyclical loading bench testing. Sequential radiographs demonstrated that the anchors locked in cancellous bone and provided consistent fixation with no loosening or lysis in 1 year of clinical follow-up. Mechanical testing demonstrated mean, pullout strength of 160.2 N (36 lbs), and the anchors did not migrate when cyclically loaded. Clinical results showed an allograft anchor is viable for rotator cuff tendon repair.

Use of an allograft bone button for rotator cuff repair.

This study aimed to determine the safety and efficacy of percutaneous myocardial laser revascularization (PMLR). Seventy-three patients with stable angina pectoris (class III or IV) who were unsuitable for conventional revascularization and had evidence of reversible ischemia by thallium-201 scintigraphy, ejection fraction of > or =25%, and myocardial wall thickness > or =8 mm were randomized to optimal medical therapy alone (n = 37) or PMLR with optimal medical therapy (n = 36). Patients were followed up at 3, 6, and 12 months. The primary end point was exercise time. Secondary end points included angina scores, left ventricular ejection fraction, quality of life, changes in medical therapy, and hospitalizations. All 36 patients randomized to PMLR underwent the procedure successfully with no periprocedure deaths. One patient developed sustained ventricular tachycardia that required electrical cardioversion, and 1 patient developed cardiac tamponade that required surgical drainage. At 12 months, exercise times improved by 109 seconds in the PMLR group but decreased by 62 seconds in the control group (p <0.01). Angina scores improved by 2 classes in 36% of PMLR-treated patients at 12 months compared with 0% of the control patients (p <0.01). We conclude that PMLR is a relatively safe procedure that provides patients with symptomatic angina relief and improvement in exercise capacity and quality of life.

Percutaneous myocardial laser revascularization in patients with refractory angina pectoris.

Evaluation of a suture seat, a biodegradable suture fastener, to eliminate knot-tying in arthroscopic rotator cuff repair.

This study examined from a health service perspective whether percutaneous myocardial laser revascularisation (PMR) plus standard medical management is cost-effective when compared with standard medical management alone in the treatment of refractory angina. This involved a cost-utility analysis using patient-specific data from a single-centre, randomised, controlled trial carried out in the United Kingdom. Of 73 patients diagnosed as having refractory angina and not suitable for conventional forms of revascularisation, 36 were randomised to PMR plus medical management and 37 to medical management alone. We collected costs to the health service of PMR and all secondary sector health care contacts and cardiac-related medication in the 12 months following randomisation. Patient utility, measured using the EuroQol EQ-5D questionnaire, was combined with 12-month survival data to generate quality-adjusted life years (QALYs). The mean 12-month cost per patient for PMR was 8,307 pounds, and that for medical management was 1,888 pounds, giving a cost difference of 6,410 pounds. The mean QALY difference favoured PMR at 0.126, giving an incremental cost per QALY of 50,873 pounds. The cost-effectiveness acceptability curve indicates that the probability of PMR being cost-effective over the first 12 months is quite low. Whilst a longer period of follow-up might indicate continued benefit from PMR, which would make the intervention economically more attractive, PMR could not be considered cost-effective based on 1-year follow-up data.

Trial-based cost-utility comparison of percutaneous myocardial laser revascularisation and continued medical therapy for treatment of refractory angina pectoris.

Considerable research indicates that "ecstasy" users perceive their memory for future intentions (prospective memory) to be impaired. However, only one empirical study to date has directly tested how this capacity is affected by ecstasy use, and this study provided relatively limited information regarding the extent, scope, or implications of problems experienced.

Prospective memory impairment in "ecstasy" (MDMA) users.

West Nile virus Kunjin subtype (WNV/KUNV) is enzootic across the tropical north of Australia, with epizootic spread into other jurisdictions. The clinical spectrum of illness in humans is poorly described. We report a clinical case of WNV/KUNV encephalitis and performed a retrospective chart audit of all cases of WNV/KUNV notified in the Northern Territory from 1992 to 2010. Thirteen cases of WNV/KUNV disease were identified; case notes were available for 10 of these presentations. Six of these patients had confirmed infection and presented with neuroinvasive illness, whereas the other four suspect cases comprised three cases with arthralgia, myalgia, and/or rash and one case with fever alone. On the available evidence, WNV/KUNV is of lower virulence compared with the New York 1999 strain. Difficulties in serological diagnosis, especially when paired acute and convalescent sera are not available, may adversely impact the accuracy of the epidemiological and clinical understanding of this virus.

West nile virus (Kunjin subtype) disease in the northern territory of Australia--a case of encephalitis and review of all reported cases.

Malaria is a notifiable disease in Australia with an average of 600 notifications per year in returned travellers or newly arrived refugees, migrants and visitors. Although endemic disease has been eliminated from the tropical north of Australia, the region remains malaria receptive due to the presence of efficient mosquito vectors. This study analyses enhanced surveillance data collected by the Centre for Disease Control on all cases of malaria notified in the Northern Territory from 1 January 2000 to 31 December 2010. There were 428 malaria episodes notified that occurred in 391 individuals with a median age of 26 years. Of these, 71.4% were male, 40.5% were Australian nationals and 38.0% were prescribed chemoprophylaxis. Primary infection consisted of 196 (51.3%) cases of Plasmodium falciparum, 165 (43.2%) P. vivax, 2 (0.5%) P. ovale, 1 (0.3%) P. malariae and 18 were mixed infections. There were 46 episodes of relapsed infection. Residents of non-malarious countries were most likely to have acquired primary infection in East Timor (40.6%), Papua New Guinea (27.8%), Indonesia (18.7%) and Africa (6.4%). Primary infection was diagnosed after a median 19 days (interquartile range (IQR) 7-69) after arrival in Australia for cases of P. vivax compared with 4 days for P. falciparum (IQR 2-11). Screening protocols led to the diagnosis of 27.2% of cases. Eighty-seven per cent of patients were admitted to hospital at the time of their malaria diagnosis with median duration of 3 days (IQR 2-4) and one patient died. Resettlement of people from endemic countries, as well as military and civilian activities, influences the prevailing notification rates and Plasmodium species type.

Imported malaria in the Northern Territory, Australia--428 consecutive cases.

The application of matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry (MS) directly to blood culture broth has potential to identify bloodstream infection earlier and facilitate timely management. We prospectively tested a novel, rapid, and inexpensive in-house spin-lysis protocol with formic acid extraction and compared MALDI-TOF MS identification of Gram-negative bacteria with traditional phenotypic methods (Phoenix™) directly from 318 BACTEC™ (Becton Dickinson, Franklin Lakes, USA) blood cultures. The MS score was ≥1.7 in 268 (91.8%) monomicrobial broths, with concordance to genus and species level of 100% and 97.0%, respectively. MALDI-TOF MS still has limited capacity to detect all species in polymicrobial broths.

Rapid identification of Gram-negative organisms from blood culture bottles using a modified extraction method and MALDI-TOF mass spectrometry.

To describe the clinical epidemiology, environmental surveillance and infection control interventions undertaken in a six-year persistence of bla-IMP-4 metallo-beta-lactamase (MBL) producing Enterobacteriaceae within a separately confined hospital burns unit in a tertiary hospital in Sydney, Australia.

Persistence of related bla-IMP-4 metallo-beta-lactamase producing Enterobacteriaceae from clinical and environmental specimens within a burns unit in Australia - a six-year retrospective study.

Sequence analysis of the internal transcribed spacer (ITS) region was employed as the gold standard method for yeast identification in the China Hospital Invasive Fungal Surveillance Net (CHIF-NET). It has subsequently been found that matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is potentially a more practical approach for this purpose. In the present study, the performance of the Vitek MS v2.0 system for the identification of yeast isolates collected from patients with invasive fungal infections in the 2011 CHIF-NET was evaluated. A total of 1,243 isolates representing 31 yeast species were analyzed, and the identification results by the Vitek MS v2.0 system were compared to those obtained by ITS sequence analysis. By the Vitek MS v2.0 system, 96.7% (n = 1,202) of the isolates were correctly assigned to the species level and 0.2% (n = 2) of the isolates were identified to the genus level, while 2.4% (n = 30) and 0.7% (n = 9) of the isolates were unidentified and misidentified, respectively. After retesting of the unidentified and misidentified strains, 97.3% (n = 1,209) of the isolates were correctly identified to the species level. Based on these results, a testing algorithm that combines the use of the Vitek MS system with selected supplementary ribosomal DNA (rDNA) sequencing was developed and validated for yeast identification purposes. By employing this algorithm, 99.7% (1,240/1,243) of the study isolates were accurately identified with the exception of two isolates of Candida fermentati and one isolate of Cryptococcus gattii. In conclusion, the proposed identification algorithm could be practically implemented in strategic programs of fungal infection surveillance.

Yeast identification algorithm based on use of the Vitek MS system selectively supplemented with ribosomal DNA sequencing: proposal of a reference assay for invasive fungal surveillance programs in China.

The resurgence of West Nile virus (WNV) in North America and Europe in recent years has raised the concerns of local authorities and highlighted that mosquito-borne disease is not restricted to tropical regions of the world. WNV is maintained in enzootic cycles involving, primarily, Culex spp. mosquitoes and avian hosts, with epizootic spread to mammals, including horses and humans. Human infection results in symptomatic illness in approximately one-fifth of cases and neuroinvasive disease in less than 1% of infected persons. The most consistently recognized risk factor for neuroinvasive disease is older age, although diabetes mellitus, alcohol excess, and a history of cancer may also increase risk. Despite the increasing public health concern, the current WNV treatments are inadequate. Current evidence supporting the use of ribavirin, interferon α, and WNV-specific immunoglobulin are reviewed. Nucleic acid detection has been an important diagnostic development, which is particularly important for the protection of the donated blood supply. While effective WNV vaccines are widely available for horses, no human vaccine has been registered. Uncertainty surrounds the magnitude of future risk posed by WNV, and predictive models are limited by the heterogeneity of environmental, vector, and host factors, even in neighboring regions. However, recent history has demonstrated that for regions where suitable mosquito vectors and reservoir hosts are present, there will be a risk of major epidemics. Given the potential for these outbreaks to include severe neuroinvasive disease, strategies should be implemented to monitor for, and respond to, outbreak risk. While broadscale mosquito control programs will assist in reducing the abundance of mosquito populations and subsequently reduce the risks of disease, for many individuals, the use of topical insect repellents and other personal protective strategies will remain the first line of defense against infection.

Timothy J. Gray

Centre for Infectious Diseases and Microbiology Laboratory Services,
Institute of Clinical Pathology and Medical Research,
Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research

Westmead hospital

Rapid Identification of Gram Negative Bacteria from Blood Culture Broth Using MALDI-TOF Mass Spectrometry