Identification of Burkholderia pseudomallei by Use of the Vitek Mass Spectrometer.

Burkholderia pseudomallei is the causative agent of melioidosis. This condition most often presents as pneumonia and bacteremia, with mortality rates of 9% to 70%. Therefore, early identification of this organism may aid in directing appropriate management. This study aimed to use the Vitek matrix-assisted laser desorption ionization-time of flight mass spectrometer to create a spectrum for the rapid identification of B. pseudomallei Spectra from 85 isolate cultures were acquired using the Vitek mass spectrometer research mode. A SuperSpectrum was created using peak matching and subsequently activated for analysis of organism identification. All 85 isolates were correctly identified as B. pseudomallei A total of 899 spectra were analyzed and demonstrated a specificity of 99.8%. Eighty-one clinical isolates were used, of which 10 were neuromelioidosis, and no discernible spectrum difference was appreciated. Spectrum acquisition from a single spot was only successful in 374/899 (41%) of isolates. This increased to 100% when 3 spots of the same extract were analyzed. The Vitek mass spectrometer can be used for the rapid identification of B. pseudomallei with a high level of specificity.

A novel serotype of enteropathogenic Escherichia coli (EPEC) as a major pathogen in an outbreak of infantile diarrhoea.

An outbreak of infantile diarrhoea was investigated in 32 children, all <2 years old, in the tropical north of Australia. Rotavirus (63%) and enteropathogenic Escherichia coli (EPEC) (59%) were the most common pathogens identified. Of the 19 EPEC isolates, 14 (74%) were of serotype O126:H12, hitherto unreported as an EPEC serotype. Other pathogens isolated included Salmonella spp. (16%), Campylobacter spp. (3%), Giardia (3%) and Shigella spp. (3%). EPEC-related gastro-enteritis is an uncommon but recognised cause of diarrhoeal outbreaks in Australia and clinicians need to be aware of the possibility of this serotype being implicated. This report highlights the disadvantages of relying on serotyping alone for the recognition of EPEC.

Antigenic epitope mapping of the M24 protein of Streptococcus pyogenes: implications for serodiagnosis of rheumatic fever.

Rheumatic fever continues to be a significant problem in Australian Aboriginal communities and developing countries worldwide. Early diagnosis could facilitate the institution of penicillin prophylaxis resulting in the prevention of recurrences of rheumatic fever. An overlapping biotinylated peptide bank of 82 peptides, based on the known sequence of Streptococcus pyogenes M24 protein, was used in a standard enzyme immunoassay. A total of 82 sera were tested from both aboriginal and non-aboriginal subjects with clinically proven rheumatic fever, rheumatic heart disease and matched controls. Two peptides with significant sequence homology at the C-terminal end were found to be discriminatory between aboriginal cases and controls. It is proposed that these peptides could be the basis of a serological test for rheumatic fever.

An in vitro study of the efficacy of rifampicin and minocycline coated umbilical venous catheters.

The use of antibiotic coated catheters has been proposed as a means of reducing catheter related sepsis. In this study, an in vitro comparison of bacterial colonisation rates was made between uncoated umbilical venous catheters and catheters coated with rifampicin and minocycline. The following parameters were determined; the direct antimicrobial effect of coated and uncoated catheter segments against a range of organisms associated with line sepsis, the assessment of the decline in antimicrobial activity in coated catheters immersed in plasma and the inhibitory efficacy of the catheters to colonisation over a 28-day period. Minocycline and rifampicin coated umbilical catheters showed a superior inhibitory effect and prevented colonisation with the commoner line-related organisms, when compared with uncoated catheters. The inhibitory effect declined after 14 days in the human plasma. Resistance to colonisation in vitro may not extend beyond 21 days.

Combination antimicrobial therapy of acute Burkholderia pseudomallei infection in a mouse model.

Burkholderia pseudomallei is the causative agent of melioidosis, a disease endemic in tropical and subtropical regions of South-East Asia and Northern Australia. Antimicrobial therapy regimens for treatment of acute septicemic melioidosis are of variable efficacy. Ceftazidime is the current antibiotic of choice and is commonly administered with other agents such as cotrimoxazole or doxycycline. The emergence of resistant strains of B. pseudomallei and the persistence of high mortality rates prompted the present study. Using an established mouse model of acute disseminated B. pseudomallei infection, we compared the efficacy of ceftazidime versus cefpirome in combination with cotrimoxazole or chloramphenicol therapy in vivo. Control mice that were infected but did not receive antibiotic therapy died within 96 hours of infection. No deaths occurred in treatment groups receiving either cephalosporin or cotrimoxazole, despite the demonstrated resistance of B. pseudomallei to cotrimoxazole in vitro. The mortality rate in treatment groups receiving either cephalosporin and chloramphenicol was 66%. These results demonstrate a comparable level of efficacy between ceftazidime and cefpirome for treatment of acute B. pseudomallei infection in mice.

Splice losses in step-index fibers: dependency on fiber-break angle.

Coupling has been measured for dry-spliced fibers as a function of break angle. The angles were measured interferometrically to about 0.1 degrees accuracy. An analysis is performed, and the measurements are found to be within 1.0% RMS of the calculation.

Triple-dose contrast-enhanced images in neurologically symptomatic HIV-positive patients.

Our purpose was to determine whether triple-dose delayed contrast-enhanced images would improve lesion detection in patients with symptomatic human immunodeficiency virus (HIV) infection. We reviewed 33 MRI studies on 29 patients. Single-dose immediate T1-weighted spin-echo (1x-T1) images were compared with delayed triple-dose images (D3x-T1). Two neuroradiologists decided which technique showed more lesions, increased lesion conspicuity and/or altered the radiologic diagnosis. The D3x-T1 technique improved lesion detection in 14 of 29 patients (48%). In two patients (7%), the improvement changed the radiologic diagnosis by showing new meningeal lesions.

Functional neuroanatomy of the frontal lobe circuits.

This article summarizes the current theories regarding the locations and functions of the three primary frontal lobe circuits. It forms the framework for structuring functional magnetic resonance imaging investigations. It can be used to assist in (a) detecting subtle lesions of the frontal circuits and (b) applying the current theories of neuropsychiatry to assess prognosis and to plan rehabilitation.

Disseminated infection due to Nocardia transvalensis coincident with Cryptococcus neoformans variety gattii meningitis.

A case of meningitis due to Cryptococcus neoformans var. gattii coincident with disseminated Nocardia transvalensis infection is reported. Nocardia infection initially progressed despite high-dose antimicrobial therapy. Although a specific immunologic defect could not be defined, in vitro lymphocyte proliferation in response to stimulation with the Nocardia isolate was reduced. It is proposed that coinfection with Cryptococcus neoformans may have contributed to the observed impairment of lymphocyte function, leading to disseminated Nocardia disease and a suboptimal treatment response.

Locally acquired Brachylaima sp. (Digenea: Brachylaimidae) intestinal fluke infection in two South Australian infants.

Eggs of a small intestinal trematode were found in the faeces of two 21-month-old children from the same rural district of South Australia who presented 18 months apart with mild abdominal pain and diarrhoea. Treatment with praziquantel resulted in egg clearance and resolution of gastrointestinal symptoms. A brachylaimid intestinal trematode involving the common house mouse, poultry and introduced European helicid snails is well established in South Australia. Both infants had been seen eating raw snails, and snails from their environment were found to be infected with metacercariae of a brachylaimid trematode.

Two contiguous outbreaks of dengue type 2 in north Queensland.

OBJECTIVES: To investigate two outbreaks of dengue type 2 in north Queensland, one in the Torres Strait beginning in late 1996, the other in a Cairns suburb in early 1997. DESIGN: Epidemiological investigation of all laboratory-confirmed cases of dengue, entomological investigation of the local environment, and laboratory analysis of the isolated dengue viruses. MAIN OUTCOME MEASURES: Numbers of confirmed and of locally acquired cases; virus serotype; comparison of nucleotide sequences between viruses isolated from the two outbreaks; and Breteau Index (BI = number of containers with larvae of the mosquito vector Aedes aegypti found per 100 houses investigated) on the affected islands and in the Cairns suburb. RESULTS: There were 201 confirmed cases of dengue in the Torres Strait outbreak, which lasted nearly seven months, and seven confirmed cases in the Cairns outbreak, which lasted about nearly 11 weeks. Most (190) were confirmed as dengue type 2. Nucleotide sequencing of viruses isolated from the two outbreaks showed they were identical. Ae. aegypti breeding sites were very common on the five Torres Strait islands surveyed (BIs, 73-219--high risk), but less so in the Cairns suburb (BI, 23). The most common breeding sites were water storage reservoirs, particularly rainwater tanks, on the outer Torres Strait islands, discarded containers (such as plastic containers, buckets and tyres) on Thursday Island, and garden items (such as flowerpot bases and jars) in Cairns. CONCLUSIONS: The virus responsible for the Cairns outbreak was most probably introduced from the Torres Strait, whereas the virus responsible for the Torres Strait outbreak was imported from Papua New Guinea. Preventive strategies tailored to specific locations are needed to reduce breeding of Ae. aegypti in north Queensland, and the consequent risk of future outbreaks of dengue.