Epidemiology of Pseudomonas aeruginosa in a tertiary referral teaching hospital

A genotypically indistinguishable strain of Pseudomonas aeruginosa (Australian epidemic strain III: AES III) has previously been found in a proportion of adults with cystic fibrosis (CF) in Tasmania, Australia. The aim of this study was to identify a source of these infections within the major tertiary referral hospital for the State of Tasmania, and to determine if this strain could be isolated from settings other than the CF lung. A total of 120 isolates of P. aeruginosa were collected from clinical and environmental sources within the hospital and from environmental locations in the hospital vicinity. These isolates were genotyped by random amplification of polymorphic DNA (RAPD)-polymerase chain reaction (PCR) and antimicrobial susceptibility testing was performed using the Clinical and Laboratory Standards Institute method. Confirmation of similar genotypes identified by RAPDePCR was performed using pulsed-field gel electrophoresis with restriction enzyme SpeI. AES III was not recovered from any source other than the respiratory secretions of CF patients. P. aeruginosa in the non-CF settings was found to be panmictic, and no cross-infection or acquisition of hospital environment strains by patients was observed

Poor clinical outcomes associated with a multi-drug resistant clonal strain of Pseudomonas aeruginosa in the Tasmanian cystic fibrosis population

Background and objective: Clonal strains of Pseudomonas aeruginosa have been identified in large cystic fibrosis (CF) centres. Whether such strains are more virulent or whether cross-infection between patients explains their widespread prevalence is unknown. This study described the epidemiology of P. aeruginosa infection in CF patients in Tasmania, Australia, an area with a high CF birth incidence. Patients in Tasmania are geographically dispersed and when this study was conducted (2003) there was no central CF clinic, with patients receiving treatment in regional hospitals. Methods: P. aeruginosa isolates from CF adults aged 15 years and over in Tasmania were genotyped using random amplified polymorphic DNA (RAPD)-PCR and clonal strains confirmed with pulsed field gel electrophoresis. Results: Airway samples were obtained from 41 patients (82% of the adult CF population). P. aeruginosa was isolated from 34 patients and nine (26%) of these individuals harboured P. aeruginosa strains with identical RAPD-PCR and pulsed field gel electrophoresis patterns (Australian Epidemic Strain III – AES III). AES III was isolated from patients in all regions of Tasmania and was distinct from the epidemic CF strains described on mainland Australia (AES I and II). The possible link between CF adults infected with AES III was attendance at family camps more than 12 years previously. Patients harbouring AES III had suffered significantly more exacerbations requiring hospitalisation during the 2 years prior to the study compared with patients infected with unique strains (P < 0.01). AES III displayed increased multi-antibiotic resistance compared with other strains (P < 0.001). Conclusions: Clonal strains of P. aeruginosa may arise even in isolated CF populations. The increased exacerbation rate in patients infected with AES III and its antibiotic resistance profile strongly suggest increased virulence

Assessment of internal quality attributes of mandarin fruit. 2. NIR calibration model robustness

The robustness of multivariate calibration models, based on near infrared spectroscopy, for the assessment of total soluble solids (TSS) and dry matter (DM) of intact mandarin fruit (Citrus reticulata cv. Imperial) was assessed. TSS calibration model performance was validated in terms of prediction of populations of fruit not in the original population (different harvest days from a single tree, different harvest localities, different harvest seasons). Of these, calibration performance was most affected by validation across seasons (signal to noise statistic on root mean squared error of prediction of 3.8, compared with 20 and 13 for locality and harvest day, respectively). Procedures for sample selection from the validation population for addition to the calibration population ('model updating') were considered for both TSS and DM models. Random selection from the validation group worked as well as more sophisticated selection procedures, with approximately 20 samples required. Models that were developed using samples at a range of temperatures were robust in validation for TSS and DM

Urease production as a marker of virulence in Pseudomonas aeruginosa

In summary, the findings of this paper show that a urease negative phenotype is a potential marker for attenuated virulence in Pseudomonas aeruginosa isolates. Further investigation, including amplification and sequencing of rpoN, followed by correlation to quantitative measures of urease enzyme production, would determine if absence of urease enzyme expression is consequent on rpoN mutation in isolates of P. aeruginosa

Networked Professional Development: Describing a learning activity design that utilizes social media and OERs

This paper reports on an outcome of a design-based research (DBR) program evaluating the design and delivery of Networked Professional Development for Teachers (NPD): a learning activity design. With the increasing use of blended and fully online spaces to support student engagement, it is critically important to develop teacher capacity of online-networked teaching skills and strategies. Having teachers participate in NPD activities is one manner in which this goal can be accomplished. The results of the research indicate that teacher participation in NPD develops TPCK skills, supports the sharing of instructional resources and engages teachers in meaningful discussions about teaching and learning. This paper provides details about the specific NPD learning activities that were delivered using social media tools and Open Educational Resources (OERs). Further research around learning supports for NPD, as well as methods to develop networked communities of practice is needed

A comparison of alternative plant mixes for conservation bio-control by native beneficial arthropods in vegetable cropping systems in Queensland Australia

Cucurbit crops host a range of serious sap-sucking insect pests, including silverleaf whitefly (SLW) and aphids, which potentially represent considerable riskto the Australian horticulture industry. These pests are extremely polyphagous with a wide host range. Chemical control is made difficult due to resistance and pollution, and other side-effects are associated with insecticide use. Consequently, there is much interest in maximising the role of biological control in the management of these sap-sucking insect pests. This study aimed to evaluate companion cropping alongside cucurbit crops in a tropical setting as a means to increase the populations of beneficial insects and spiders so as to control the major sap-sucking insect pests. The population of beneficial and harmful insects, with a focus on SLW and aphids, and other invertebrates were sampled weekly on four different crops which could be used for habitat manipulation: Goodbug Mix (GBM; a proprietary seed mixture including self-sowing annual and perennial herbaceous flowerspecies); lablab (Lablab purpureus L. Sweet); lucerne (Medicago sativa L.); and niger (Guizotia abyssinica (L.f.) Cass.). Lablab hosted the highest numbers of beneficial insects (larvae and adults of lacewing (Mallada signata (Schneider)), ladybird beetles (Coccinella transversalis Fabricius) and spiders) while GBM hosted the highest numbers of European bees (Apis mellifera Linnaeus) and spiders. Lucerne and niger showed little promise in hosting beneficial insects, but lucerne hosted significantly more spiders (double the numbers) than niger. Lucerne hosted significantly more of the harmful insect species of aphids (Aphis gossypii (Glover)) and Myzus persicae (Sulzer)) and heliothis (Heliothis armigera Hübner). Niger hosted significantly more vegetable weevils (Listroderes difficillis (Germar)) than the other three species. Therefore, lablab and GBM appear to be viable options to grow within cucurbits or as field boundary crops to attract and increase beneficial insects and spiders for the control of sap-sucking insect pests. Use of these bio-control strategies affords the opportunity to minimise pesticide usage and the risks associated with pollution

Decreased virulence of cystic fibrosis Pseudomonas aeruginosa in Dictyostelium discoideum

The characteristics of clinical and environmental isolates of Pseudomonas aeruginosa from both hospital and community settings were analyzed in a eukaryotic virulence model employing the AX2 and X22 mutants of Dictyostelium discoideum. Thirty-one strains, including two Australian epidemic strains, of P. aeruginosa were analyzed, five from environmental sources, six from clinical sources other than cystic fibrosis (CF) patients and nineteen from CF patients’ respiratory secretions. The majority of CF isolates almost uniquely supported the growth of D. discoideum. CF isolates of P. aeruginosa were found to be less virulent than isolates from other sources. Varying degrees of inhibition of the developmental cycle of D. discoideum when growing on CF isolates were also noted. This is the first description of P. aeruginosa isolates from clinical and environmental sources supporting the growth of D. discoideum

Assessment of internal quality attributes of mandarin fruit. 1. NIR calibration model development

The utility of near infrared spectroscopy as a non-invasive technique for the assessment of internal eating quality parameters of mandarin fruit (Citrus reticulata cv. Imperial) was assessed. The calibration procedure for the attributes of TSS (total soluble solids) and DM (dry matter) was optimised with respect to a reference sampling technique,scan averaging, spectral window, data pre-treatment (in terms of derivative treatment and scatter correction routine) and regression procedure. The recommended procedure involved sampling of an equatorial position on the fruit with 1 scan per spectrum, and modified partial least squares model development on a 720-950-nm window, pre-treated as first derivative absorbance data (gap size of 4 data points) with standard normal variance and detrend scatter correction. Calibration model performance for the attributes of TSS and DM content was encouraging (typical Rc2 of >0.75 and 0.90, respectively; typical root mean squared standard error of calibration of <0.4 and 0.6% respectively), whereas that for juciness and total acidity was unacceptable. The robustness of the TSS and DM calibrations across new populations of fruit is documented in a companion study

Evaluation of students’ clinical performance post-simulation training

Traditionally in Australia, sonographer skills are learnt on patients in clinical practice. A four-year undergraduate-postgraduate course introduced ultrasound simulation to prepare novice sonographer students for interaction with patients. Second-year students learnt psychomotor and patient-sonographer communication skills during simulation using commercial ultrasound machines and volunteer year-group peers as standardised patients. This paper reports on the transfer of the ultrasound skills learnt in simulation to clinical practice

Acid mine drainage from the historic Mt Morgan gold mine : devastating to river water quality, and fish

Contaminative drainage waters from the historic abandoned Mount Morgan gold mine (central Queensland) are acidic, contain high levels of heavy metals and sulphate and have leached into the adjacent Dee River basin over 100 years. This paper reviews a current study which quantifies the discharge impacts on the water quality and fish inhabitants at a number of sites both upstream and downstream of the mine site with emphasis on distribution of contaminants during summer 2006. Pollutants discharged into the Dee River greatly diminished the water quality, and also negatively affected aquatic life, especially fish. The water is very acidic (pH 2.8) and concentrations of metals and sulphates are much higher in samples close to the mine compared with other sites. Results for most sites in the Dee River indicated that metal concentrations in the water generally exceeded ANZECC (2000) trigger levels for Al, Cu, and Zn. For Cd, the highest value observed (0.0592mg/L) was at Kenbula (closest to the mine i.e. 5km from the mine).Subsequent analysis of concentrations of heavy metals in five species of fish – Rainbow Fish (Melanotaenia splendid), Fly Specked Hardihead (Craterocephalus stercusmuscaru), Glass Perchlet (Ambassis agassizii), Spangled Perch (Leiopotherapon unicolour) and Purple Spotted Gudgeon (Mogurnda adspersa) – revealed that metal concentrations generally declined with distance from the mine but not a single fish was caught at the site closest to the mine. Al (1100mg/L), and Cu (61.6 mg/L) concentrations in fish species at Penny Royal (22.2 km from the mine) exceeded ANZFA (2000) maximum permitted levels for human consumption whereas Cd (0.05 to 0.3 mg/L), and Zn (100 to 195 mg/L) were also high, but below ANZFA levels. These results demonstrate clearly that, even though the Mt Morgan mine is no longer operational, the plume of contaminated acidic water originating from the mine continues to enter the Dee River and presents a significant threat to the environment