Phenotypic and genetic characterization of clinical isolates of CDC coryneform group A-3: proposal of a new species of Cellulomonas, Cellulomonas denverensis sp. nov

CDC coryneform group A-3 bacteria are rare human pathogens. In this study, six group A-3 isolates (two from blood, one from cerebrospinal fluid, and one each from homograft valve, lip wound, and pilonidal cyst) were compared to the type strains of phenotypically related organisms, Cellulomonas fimi, Cellulomonas hominis, Oerskovia turbata, and Sanguibacter suarezii, and characterized by phenotypic, chemotaxonomic, and genotypic studies. DNA-DNA reassociation analysis identified two genomic groups, and phylogenetic analysis of the 16S rRNA gene sequence identified the taxonomic positions of these groups to genus level. Two groups were defined, and both were more closely related to Cellulomonas species: one group of three strains, for which we propose the new species Cellulomonas denverensis sp. nov., with the type strain W6929 (ATCC BAA-788(T) or DSM 15764(T)), was related to C. hominis ATCC 51964(T) (98.5% 16S rRNA gene sequence similarity), and the second group of three strains was related to C. hominis ATCC 51964(T) (99.8 to 99.9% 16S rRNA gene sequence similarity). The definition of this new Cellulomonas species and the confirmation of three strains as C. hominis serve to further clarify the complex taxonomy of CDC coryneform group A-3 bacteria and will assist in our understanding of the epidemiology and clinical significance of these microorganisms.     

Molecular epidemiologic evaluation of endocarditis due to Oerskovia turbata and CDC group A-3 associated with contaminated homograft valves

Oerskovia turbata is an unusual bacterial cause of endocarditis and septicemia in immunocompromised patients. In this study, we compared 12 isolates from a 1975 medical center cluster, 11 originally identified as O. turbata (four from the blood of a homograft aortic valve-associated endocarditis patient and seven from contaminated homograft valves) and one CDC group A-3 strain from the blood of a second endocarditis patient with fatal outcome, with eight control strains from unrelated locations. The control strains included type and reference strains of O. turbata, Cellulomonas hominis, and CDC group A-3. The four blood isolates from the first patient and six of the valve isolates shared identical biochemical, antimicrobial susceptibility, and BglI ribotype patterns that differed from the second patient's isolate and control strains. The blood isolate from the second patient and the remaining valve isolate shared a phenotypic and genotypic profile and were phenotypically identical to, but epidemiologically different from, the CDC group A-3 reference strain with the strain-specific enzyme. Also, these isolates differed from the type strain and the other reference strains of C. hominis and O. turbata. Our results indicate that the four blood isolates from the first patient and six of the homograft valve isolates represent a single clone of O. turbata associated with endocarditis. Additionally, our results indicate that the blood isolate from the second patient and one of the homograft valve isolates differ from O. turbata and C. hominis and represent a unique clone of CDC group A-3 associated with fatal endocarditis.     

Rapid identification of Nocardia farcinica clinical isolates by a PCR assay targeting a 314-base-pair species-specific DNA fragment

Nocardia farcinica is the most clinically significant species within the Nocardia asteroides complex. Differentiation of N. farcinica from other members of N. asteroides complex is important because this species characteristically demonstrates resistance to several extended-spectrum antimicrobial agents. Traditional phenotypic characterization of this species is time- and labor-intensive and often leads to misidentification in the clinical microbiology laboratory. We previously observed a 409-bp product for all strains of N. farcinica by using randomly amplified polymorphic DNA analysis with the primer DKU49. In this investigation, the 409-bp fragment was sequenced and then used to design a specific primer pair, Nf1 (16-mer) and Nf2 (16-mer), complementary to the 409-bp fragment. PCR amplification of genomic DNA from 28 N. farcinica isolates with Nf1 and Nf2 generated a single intense 314-bp fragment. The specificity of the assay with these primers was verified, since there were no PCR amplification products observed from heterologous nocardial species (n = 59) or other related bacterial genera (n = 41). Restriction enzyme digestion using CfoI and direct sequencing of the 314-bp fragment further confirmed the specificity of the assay for N. farcinica. This highly sensitive and specific PCR assay provides a rapid (within 1 day of obtaining DNA) method for identification of this medically important emerging pathogen. Rapid diagnosis of N. farcinica infection may allow for earlier initiation of effective therapy, thus improving patient outcome.     

Development of eMed: a comprehensive, modular curriculum-management system.

In 2001 the University of New South Wales Faculty of Medicine embarked on designing a curriculum-management system to support the development and delivery of its new, fully integrated, outcome-based, six-year undergraduate medicine program. The Web-enabled curriculum-management system it developed is known as eMed, and it comprises a suite of integrated tools used for managing graduate outcomes, content, activities, and assessment in the new program. The six main tools are a curriculum map, timetable, student portfolio, peer feedback tool, assessment tracking, and results tools. The eMed functions were determined by organizational and curricular needs, and a business management perspective guided its development. The eMed project was developed by a multidisciplinary team, and its successful development was achieved mostly by methodically identifying the scope of each tool and the business processes it supports. Evaluation results indicated a high level of user acceptance and approval. The eMed system is a simple yet effective educational technology system that allows users to evaluate and improve the curriculum in real time. As a second-generation curriculum-management system, eMed is much more than an educational administration system; it is a knowledge network system used by staff and students to transform data and information into knowledge and action. The integration of learning and assessment activities data in the one system gives a depth of curriculum information that is unusual and that allows for data-based decision making. Technologically, eMed helps to keep the medicine program up to date. Organizationally, it strengthens the school's data-driven decision-making process and knowledge network culture.     

Use of a repetitive DNA probe to type clinical and environmental isolates of Aspergillus flavus from a cluster of cutaneous infections in a neonatal intensive care unit

Aspergillus flavus is second to A. fumigatus as a cause of invasive aspergillosis, but no standard method exists for molecular typing of strains from human sources. A repetitive DNA sequence cloned from A. flavus and subcloned into a pUC19 vector, pAF28, was used to type 18 isolates from diverse clinical, environmental, and geographic sources. The restriction fragment length polymorphisms generated with EcoRI- or PstI-digested genomic DNA and probed with digoxigenin-labeled pAF28 revealed complete concordance between patterns. Eighteen distinct fingerprints were observed. The probe was used to investigate two cases of cutaneous A. flavus infection in low-birth-weight infants in a neonatal intensive care unit (NICU). Both infants were transported by the same ambulance and crew to the NICU on the same day. A. flavus strains of the same genotype were isolated from both infants, from a roll of tape used to fasten their umbilical catheters, from a canvas bag used to store the tape in the ambulance, and from the tape tray in the ambulance isolette. These cases highlight the need to consider exposures in critically ill neonates that might occur during their transport to the NICU and for stringent infection control practices. The hybridization profiles of strains from a second cluster of invasive A. flavus infections in two pediatric hematology-oncology patients revealed a genotype common to strains from a definite case patient and a health care worker. A probable case patient was infected with a strain with a genotype different from that of the strain from the definite case patient but highly related to that of an environmental isolate. The high degree of discrimination and reproducibility obtained with the pAF28 probe underscores its utility for typing clinical and environmental isolates of A. flavus.     

A dual-task tool for quantifying normal comprehension of aphasic connected speech production: A constructive replication

Background: Deficits of attention or its control secondary to brain damage have been proposed as all or part of the underlying mechanisms for the linguistic impairments that characterise aphasia (Clark & Robin, 1995; Granier, Robin, Shapiro, Peach, & Zimba, 2000; McNeil, 1982, 1988; McNeil, Odell, & Tseng, 1991; Murray, Holland, & Beeson, 1997a; Tseng, McNeil, & Milenkovic, 1993). McNeil, Doyle, Hula, Rubinsky, Fossett, and Matthews (2004) developed a set of tasks to quantify the difficulty that normal listeners have in understanding the language production of persons with varying amounts of aphasia. In their dual-task study, a significant decrement was found in the visual–manual tracking accuracy of normal older individuals while concurrently listening to the connected language of a person with moderate, as compared to mild, aphasia. No performance costs were observed on the listening tasks across three tracking difficulty levels. Possible reasons for the unidirectional performance cost were speculated and the present study was designed to investigate one of them.Aims: Using the same story comprehension task used in the previous study and the same visual–manual tracking task, but increased in difficulty, this study sought to investigate whether the increased demands of the tracking task were sufficient to elicit a concurrent cost on story comprehension performance.Methods & Procedures: A total of 24 normal participants performed the tracking and story comprehension tasks concurrently and in isolation. Story retell performance was evaluated within subjects across two tracking difficulty levels (easy and hard) and tracking performance was evaluated between subjects across three story difficulty levels (no story, mild difficulty, and moderate difficulty).Outcomes & Results: Tracking performance varied significantly across story task difficulty in the easy tracking condition, with participants demonstrating better tracking performance in the mild story condition than in either the moderate story or no story conditions. None of the comparisons made with the harder tracking condition reached significance. There was no effect of tracking difficulty on story comprehension as measured by subsequent story retell performance.Conclusions: The findings from this study replicate the findings from the McNeil et al. (2004) study that these dual-tasks show a reliable cost of story difficulty on concurrent tracking performance. Contrary to predictions, no effect of tracking difficulty on story retell performance was found, despite the increased tracking difficulty used compared to the previous study. While this finding does diminish the probability that insufficient tracking task difficulty was the source of the unidirectional costs in the previous study, it leaves a number of alternative explanations for the findings viable and unaddressed.     

Measuring communicative functioning in community‐dwelling stroke survivors: Conceptual foundation and item development

Background: Studies employing item response theory methods to evaluate communicative functioning assessment items have found that a broad range of communication tasks and activities may fit a unidimensional measurement model, but that additional item content is needed to extend the range of ability effectively measured by the small subset of items that have been evaluated.

Aims: To describe the item identification, evaluation, and development process used to substantiate the content relevance and representativeness of a set of communicative functioning assessment items targeting community‐dwelling stroke survivors.

Methods & Procedures: Electronic and secondary references were searched to identify assessment tools with item content designed to measure communicative functioning in adults with neurogenic communication disorders. Candidate items were evaluated using face‐to‐face interviewer‐assisted survey groups conducted independently with communicatively impaired stroke survivors (n = 59) and their communicative partners (n = 61). Web‐based surveys were employed to evaluate candidate items from the perspective of practising speech‐language pathologists (n = 114).

Outcomes & Results: A total of 673 items were identified from 33 instruments. A total of 426 met the specified concept definition; 211 were determined to be non‐redundant; 166 were identified by key stakeholders as unambiguous, relevant, and moderately to very important to daily functioning.

Conclusions: The item pool developed samples a representative range of communication behaviours, activities, and life situations that are relevant to community‐dwelling stroke survivors. Further research using item response theory methods is required to substantiate the construct dimensionality and range of ability effectively measured by the item pool, and to evaluate dynamic assessment algorithms designed to minimise response burden.     

Comparison of antibody, antigen, and metabolite assays for hospitalized patients with disseminated or peripheral candidiasis.

Repeat serum samples from 22 patients with proven disseminated candidiasis and 42 with simple peripheral colonization were assayed for Candida antibodies by coelectrosyneresis, immunoprecipitation, and A and B immunofluorescence, for metabolites by D-arabinitol measurement, and for antigens by the mannan immunoassay and Cand-tec latex agglutination (mean number of samples tested, 2.5 per patient). For the antibody and metabolite assays, the results showed no statistical difference between the two groups. By contrast, the results of both antigen assays were positive for a significantly larger number of patients with disseminated candidiasis than of those with simple peripheral colonization. Results were regardless of whether the patients were neutropenic. They were not predictive of death. We calculated that the mannan antigen assay had 29% sensitivity and 97% specificity for the diagnosis of disseminated candidiasis. Likelihood ratios of a positive and a negative result of this test were 9.2 and 0.7, respectively, for this diagnosis. In the latex agglutination test, likelihood ratios were 2.5, 1.5, 1.6, and 0.3 when the test was positive for dilutions of 1/8, 1/4, and 1/2 and was negative, respectively.