Age differences to methylphenidate-NAc neuronal and behavioral recordings from freely behaving animals

Methylphenidate (MPD) is a psychostimulant that is widely prescribed to treat attention deficit-hyperactivity disorder, but it is abused recreationally as well. The nucleus accumbens (NAc) is part of the motivation circuit implicated in drug-seeking behaviors. The NAc neuronal activity was recorded alongside the behavioral activity from young and adult rats to determine if there are significant differences in the response to MPD. The same dose of MPD elicits behavioral sensitization in some animals and behavioral tolerance in others. In adult animals, higher doses of MPD resulted in a greater ratio of tolerance/sensitization. Animals who responded to chronic MPD with behavioral sensitization usually exhibited further increases in their NAc neuronal firing rates as well. Different upregulations of transcription factors (ΔFOSB/CREB), variable proportions of D1/D2 dopamine receptors, and modulation from other brain areas may predispose certain animals to express behavioral and neuronal sensitization versus tolerance to MPD.

Prostate-Specific Antigen Test Utilization in a Major Canadian City

OBJECTIVES

To review the utilization of prostate-specific antigen (PSA) testing in Winnipeg, a major Canadian city, and to compare PSA testing rates between Winnipeg and Calgary, another major Canadian city of comparable size.

METHODS

PSA testing results were reviewed by year and age group. We focused our studies in years 2011 and 2016, for which census demographic data are available.

RESULTS

In Winnipeg, the PSA testing rates (patients with one or two PSA tests divided by the male population) showed a declining trend over years from 2008 to 2017. For almost all age groups, PSA testing rates in 2016 decreased in comparison to those in 2011. For age older than 40 years, the relative percentage decreases were 14% to 20%.In 2011, Winnipeg PSA testing rates were consistently higher than those in Calgary for all age groups. For age older than 40 years, the relative percentage differences were 36% to 50%.In addition, 41% and 40% of patients in Winnipeg who underwent PSA testing were younger than 50 years or older than 69 years in 2011 and 2016, respectively.

CONCLUSIONS

PSA testing utilization may be falling short of optimal rates. There is a need to reinforce the optimal use of clinical recommendations.

Guidelines from the Canadian Association of Pathologists for establishing a telepathology service for anatomic pathology using whole-slide imaging

The use of telepathology for clinical applications in Canada has steadily become more attractive over the last 10 years, driven largely by its potential to provide rapid pathology consulting services throughout the country regardless of the location of a particular institution. Based on this trend, the president of the Canadian Association of Pathologists asked a working group consisting of pathologists, technologists, and healthcare administrators from across Canada to oversee the development of guidelines to provide Canadian pathologists with basic information on how to implement and use this technology. The guidelines were systematically developed, based on available medical literature and the clinical experience of early adopters of telepathology in Canada. While there are many different modalities and applications of telepathology, this document focuses specifically on whole-slide imaging as applied to intraoperative pathology consultation (frozen section), primary diagnosis, expert or second opinions and quality assurance activities. Applications such as hematopathology, microbiology, tumour boards, education, research and technical and/or standard-related issues are not covered.

Development of a competitive enzyme linked immunosorbent assay to identify epitope specific antibodies in recipients of the U.S. licensed anthrax vaccine

Vaccination with anthrax vaccine adsorbed (AVA) results in the production of protective antigen (PA) specific antibodies, which play an important protective role against anthrax toxins. Analyzing the specificity of serum antibodies generated in response to AVA vaccination can provide insight into the mechanisms of protective immunity against this important pathogen. The goal of this study was to develop a competitive enzyme linked immunosorbent assay (cELISA) to test human immune serum for antibodies specific for a known lethal toxin neutralizing epitope in PA. PA-specific antibodies in sera from individuals who received the six-dose AVA vaccine series competed for binding to immobilized PA with monoclonal antibody F20G75, which binds to a linear epitope in domain 2 of PA and neutralizes lethal toxin activity in vitro. These results suggest that antibodies in human AVA vaccinee serum recognize the same epitope as F20G75, or one in close proximity to it, and may serve a protective role against anthrax lethal toxin. This assay may be used for serological confirmation of successful immunization against anthrax and for the identification of antibodies in human vaccinee serum that recognize protective epitopes on PA.

Production and characterization of a monoclonal antibody to Francisella tularensis lipopolysaccharide

Having the capacity to detect and identify pathogens that can be employed in a bioterror attack is critical from both a public health and defence perspective. Immunodiagnostic assays are useful tools for enhancing such detection capabilities. In order to develop an immunodiagnostic assay for the detection of Francisella tularensis, a murine monoclonal antibody (MAb) was developed, using the live vaccine strain (LVS) of F. tularensis as the inoculating antigen. A single MAb, F94G2-1, which is specific for the lipopolysaccharide (LPS) of this bacterium was developed and characterized. An indirect ELISA using purified LPS was effective in determining reactivity of the MAb against its target. An immunodotblot and a manually printed antigen microarray were also tested as suitable detection methods. Both assays showed that MAb F94G2-1 has excellent specificity for F. tularensis LPS and demonstrate the utility of using the same MAb in a variety of immunodiagnostic applications.

Production and characterization of neutralizing monoclonal antibodies that recognize an epitope in domain 2 of Bacillus anthracis protective antigen

Antibodies against the protective antigen (PA) of Bacillus anthracis play a key role in response to infection by this important pathogen. The aim of this study was to produce and characterize monoclonal antibodies (mAbs) specific for PA and to identify novel neutralizing epitopes. Three murine mAbs with high specificity and nanomolar affinity for B. anthracis recombinant protective antigen (rPA) were produced and characterized. Western immunoblot analysis, coupled with epitope mapping using overlapping synthetic peptides, revealed that these mAbs recognize a linear epitope within domain 2 of rPA. Neutralization assays demonstrate that these mAbs effectively neutralize lethal toxin in vitro.

Early analgesia for children with acute abdominal pain

OBJECTIVES

The objectives of this study were to determine whether the administration of morphine to children with acute abdominal pain would impede the diagnosis of appendicitis and to determine the efficacy of morphine in relieving the pain.

METHODS

This was a double-blind, randomized, placebo-controlled trial involving 5- to 16-year-old children who presented to the emergency department of a children's hospital with a chief complaint of acute abdominal pain that was thought by the pediatric emergency attending physician to require a surgical consultation. Subjects were randomized to receive intravenously administered morphine or normal saline solution. Clinical data and the emergency physician's confidence in his or her clinical diagnosis (0-100%) were recorded systematically with a standardized form. This was repeated 15 minutes after administration of the study medication. The surgeon assessed the child within 1 hour and completed a similar data collection sheet. Pain was assessed, with a color analog scale, before and after study medication administration. Each subject was monitored for 2 weeks after enrollment.

RESULTS

One hundred eight children were enrolled; 52 received morphine and 56 received a placebo saline solution. There were no differences between groups in demographic variables or the degree of pain. There were no differences between groups in the diagnoses of appendicitis or perforated appendicitis or the number of children who were observed and then underwent laparotomy. The reduction in the mean pain score was significantly greater in the morphine group (2.2 vs 1.2 cm). The emergency physicians' and surgeons' confidence in their diagnoses was not affected by the administration of morphine.

CONCLUSIONS

Our data show that morphine effectively reduces the intensity of pain among children with acute abdominal pain and morphine does not seem to impede the diagnosis of appendicitis.

Development and characterisation of neutralising monoclonal antibody to the SARS-coronavirus

There is a global need to elucidate protective antigens expressed by the SARS-coronavirus (SARS-CoV). Monoclonal antibody reagents that recognise specific antigens on SARS-CoV are needed urgently. In this report, the development and immunochemical characterisation of a panel of murine monoclonal antibodies (mAbs) against the SARS-CoV is presented, based upon their specificity, binding requirements, and biological activity. Initial screening by ELISA, using highly purified virus as the coating antigen, resulted in the selection of 103 mAbs to the SARS virus. Subsequent screening steps reduced this panel to seventeen IgG mAbs. A single mAb, F26G15, is specific for the nucleoprotein as seen in Western immunoblot while five other mAbs react with the Spike protein. Two of these Spike-specific mAbs demonstrate the ability to neutralise SARS-CoV in vitro while another four Western immunoblot-negative mAbs also neutralise the virus. The utility of these mAbs for diagnostic development is demonstrated. Antibody from convalescent SARS patients, but not normal human serum, is also shown to specifically compete off binding of mAbs to whole SARS-CoV. These studies highlight the importance of using standardised assays and reagents. These mAbs will be useful for the development of diagnostic tests, studies of SARS-CoV pathogenesis and vaccine development.

Clinical and laboratory features of Mycobacterium porcinum

Recent molecular studies have shown Mycobacterium porcinum, recovered from cases of lymphadenitis in swine, to have complete 16S rDNA sequence identity and >70% DNA-DNA homology with human isolates within the M. fortuitum third biovariant complex. We identified 67 clinical and two environmental isolates of the M. fortuitum third biovariant sorbitol-negative group, of which 48 (70%) had the same PCR restriction enzyme analysis (PRA) profile as the hsp65 gene of M. porcinum (ATCC 33776(T)) and were studied in more detail. Most U.S. patient isolates were from Texas (44%), Florida (19%), or other southern coastal states (15%). Clinical infections included wound infections (62%), central catheter infections and/or bacteremia (16%), and possible pneumonitis (18%). Sequencing of the 16S rRNA gene (1,463 bp) showed 100% identity with M. porcinum ATCC 33776(T). Sequencing of 441 bp of the hsp65 gene showed four sequevars that differed by 2 to 3 bp from the porcine strains. Clinical isolates were positive for arylsulfatase activity at 3 days, nitrate, iron uptake, D-mannitol, i-myo-inositol, and catalase at 68 degrees C. They were negative for L-rhamnose and D-glucitol (sorbitol). Clinical isolates were susceptible to ciprofloxacin, sulfamethoxazole, and linezolid and susceptible or intermediate to cefoxitin, clarithromycin, imipenem, and amikacin. M. porcinum ATCC 33776(T) gave similar results except for being nitrate negative. These studies showed almost complete phenotypic and molecular identity between clinical isolates of the M. fortuitum third biovariant D-sorbitol-negative group and porcine strains of M. porcinum and confirmed that they belong to the same species. Identification of M. porcinum presently requires hsp65 gene PRA or 16S rRNA or hsp65 gene sequencing.

Pulsed-field gel electrophoresis study of Mycobacterium abscessus isolates previously affected by DNA degradation

DNA degradation (which results in a smear pattern) occurs with almost 50% of Mycobacterium abscessus strains during pulsed-field gel electrophoresis (PFGE). We assessed the potential benefit of using thiourea-containing buffer with M. abscessus by studying 69 isolates not previously typeable by PFGE (i.e., those with a smear pattern). Random (epidemiologically unrelated) isolates that were typeable (no smear pattern) were included as controls. Genomic DNA was digested with DraI, XbaI, and AseI. PFGE gels were run in regular gel buffer with and without 100 muM thiourea. All 69 isolates that generated smear patterns had clear band profiles when the thiourea buffer was used. These isolates were divided into only 30 patterns with DraI, 20 patterns with XbaI, and 20 patterns with AseI. The molecular profiles were all closely or possibly related, and the differences between the isolates ranged from zero to six bands. By multilocus enzyme electrophoresis (MEE), 45 of 53 smear isolates (85%) belonged to two closely related electrophoretic types. These isolates contained at least one enzyme allele seen almost exclusively in this group. Isolates without smear patterns were unaffected by thiourea and produced unrelated PFGE profiles, as well as multiple MEE types. The hsp65 and 16S rRNA gene sequences of the isolates with smear patterns were identical to those of M. abscessus type strain ATCC 19977, which had a nonsmear pattern, suggesting that this clone is a subgroup within M. abscessus. This demonstrates that the inability to type M. abscessus by PFGE is associated with a single clone of organisms.

Analgesic use in children with acute abdominal pain

STUDY OBJECTIVE

To determine the frequency of analgesic use in children (5 to 17 years inclusive) who present to a pediatric emergency department with acute abdominal pain.

METHODS

A retrospective medical record review of patients presenting to a children's hospital over a 1-year period with a chief complaint of abdominal pain and subsequently referred to the pediatric surgical service. The records were reviewed to determine emergency department analgesic use, patient disposition, and laparotomy rate.

RESULTS

Two hundred ninety patients met our inclusion criteria. Of the patients seen initially by emergency physicians, 14.3% received analgesics, while those seen directly by the surgical service received analgesia 15.4% of the time. The laparotomy rate for the 290 patients was 46.6%.

CONCLUSIONS

Analgesic use in children who present to the emergency department with acute abdominal pain and require a surgical consultation was very low, although half required a laparotomy. Prospective studies are needed to determine the efficacy and safety of analgesic use in this setting.

Mycobacterium parascrofulaceum sp. nov., novel slowly growing, scotochromogenic clinical isolates related to Mycobacterium simiae

A group of pigmented, slowly growing mycobacteria identified by 16S rRNA gene sequencing as ‘MCRO 33’ (GenBank accession no. AF152559) have been isolated from several clinical specimens in various laboratories across Canada. Genotypically, the organism is most closely related to Mycobacterium simiae. However, it presents with a similar phenotypic profile to Mycobacterium scrofulaceum. Several reference strains obtained from ATCC and TMC culture collections, previously identified as M. scrofulaceum or M. simiae, have also been found to possess the MCRO 33 16S rRNA gene sequence. Biochemical testing, susceptibility testing, HPLC, hsp65 gene and 16S–23S spacer (ITS1) sequencing were performed on clinical and reference strains to characterize further this unique species. Of the clinical strains, one was isolated from a cervix biopsy whereas all other clinical isolates were obtained from respiratory samples. In one patient, symptoms, imaging and repeat clinical specimens positive on culture for this organism were suggestive of active clinical disease. The description of this species, for which the name Mycobacterium parascrofulaceum sp. nov. is proposed, follows the present trend of a large number of novel Mycobacterium species identified due in great part to sequence-based methods. The type strain is HSC68T (=ATCC BAA-614T=DSM 44648T).

Mycobacterium saskatchewanense sp. nov., a novel slowly growing scotochromogenic species from human clinical isolates related to Mycobacterium interjectum and Accuprobe-positive for Mycobacterium avium complex

A pigmented, slowly growing Mycobacterium avium complex AccuProbe-positive organism was isolated from the sputum and pleural fluid of a 72-year-old female with bronchiectasis. The unusual morphology of the organism prompted further identification by 16S rRNA gene sequencing, revealing a perfect identity with previously uncharacterized strain Mycobacterium sp. MCRO 8 (GenBank accession no. X93034), with the closest established species by 16S rDNA analysis being Mycobacterium interjectum. HPLC of the organism corresponded to previously obtained patterns identified as M. interjectum-like and, upon sequence evaluation of a selection of strains with a similar profile, more were subsequently identified as MCRO 8. A total of 16 strains isolated from human respiratory samples were evaluated in the characterization of this novel species, for which the name Mycobacterium saskatchewanense sp. nov. is proposed. The type strain is strain 00-250T (=ATCC BAA-544T=DSM 44616T=CIP 108114T).

Evaluation of RIDOM, MicroSeq, and Genbank services in the molecular identification of Nocardia species

The molecular identification of Nocardia species, when compared to phenotypic identification, has two primary advantages: rapid turn-around time and improved accuracy. The information content in the 5'-end of the 16S ribosomal RNA gene is sufficient for identification of most bacterial species. An evaluation was performed to demonstrate the quality of results provided by two specialized databases (RIDOM and MicroSeq 500 versions 1.1 and 1.4.3, library version 500-0125, respectively) and the more general GenBank database. In addition, these results were compared with phenotypic identifications. Partial 5'-16S rDNA sequences from 64 culture collection strains (DSM, CIP, JCM, and ATCC) were derived, in duplicate, independently in two laboratories. Furthermore, the sequences and the conventional identification results of 91 clinical Nocardia isolates were determined. With the exception of N. soli and N. cummidelens, all Nocardia type strains were distinguishable using 5'-16S rDNA sequencing. Assuming a normal distribution for the pairwise distances of all unique Nocardia sequences and choosing a reporting criterion of > or = 99.12% similarity for a "distinct species", a statistical error probability of 1.0% can be calculated. When the various databases were searched with the clinical isolate sequences RIDOM gave a perfect match in 71.4% of cases whereas MicroSeq yielded a perfect match in only 26.4%. The GenBank service gave a 100% similarity in 59.3% but in 70.4% of these cases the results obtained were not exclusive for a single Nocardia species. Conventional methods gave a correct identification in 59 cases, although most recent taxonomic changes were not taken into account. The RIDOM service (http://www.ridom-rdna.de/) is in the process of making available a comprehensive and high-quality database for bacterial identification purposes and provides excellent results for the majority of Nocardia isolates.

Strain-related virulence of the dominant Mycobacterium tuberculosis strain in the Canadian province of Manitoba

SETTING

The Canadian province of Manitoba.

OBJECTIVE

To confirm the putative hypervirulence observed in Mycobacterium tuberculosis Type1 strain and further characterize the progression and manifestation of pulmonary tuberculosis caused by this strain in comparison to other common clinical isolates from Manitoba.

DESIGN

C3H and BALB/c mice were exposed to aerosols either of Type1, Type2, Type5, Type72 or H37Rv strain to study their respective survival profiles. Additionally, bacillary loads and lung histology were examined at 15 days post-exposure.

RESULTS

In both mouse models, Type-1 infected mice succumbed to disease significantly earlier than other strains (p < or =0.0002). Differences between average log(10) CFU values between clinical isolates were less than 1log(10) difference. In C3H mice, the amount of granulomatous inflammation was highest in Type1 infected mice but not significantly different than all clinical strains. In contrast, BALB/c mice infected with Type1 induced the lowest amount of granulomatous inflammation compared to other clinical isolates.

CONCLUSION

Our results indicate that although mice infected with the Type1 strain died significantly earlier than mice infected with other clinical strains in both C3H and BALB/c mice, the hypervirulence of the Type1 strain is not attributed to the growth rate of the organism, as differences in growth between clinical M. tuberculosis isolates were insignificant.

Evaluation of sputum decontamination methods for Mycobacterium tuberculosis using viable colony counts and flow cytometry

Continuous monitoring systems for the detection of Mycobacterium tuberculosis are reported to have higher contamination rates than traditional radiometric technologies. Multiple decontamination methods have recently been reported in an attempt to optimize contamination rates for these systems. In this study, several decontamination methods for sputum were evaluated using viable colony count and flow cytometry. The decontamination protocols evaluated include N-Acetyl-L-Cysteine-Sodium Hydroxide (NALC-NaOH), modified Petroffs's method, and the Yamane procedure. Several parameters of the NALC-NaOH method were analyzed including final NaOH concentrations of 0.5-3%, NaOH exposure times of 0-30 min, and variations in resuspension media for the resultant pellet. All decontamination methods were performed on pooled and sterilized sputum seeded separately with either a mixture of common contaminating bacteria or M. tuberculosis H37Ra. Viability of organisms following decontamination was assessed by both colony counts and flow cytometric analysis. Flow cytometry viability assays utilized a combination of viability dyes and reference beads to determine viable organism concentrations. The results indicated that no decontamination method was clearly superior, however a concentration of 1-2% NaOH and an increase in the time of NaOH exposure to 30 min will effectively kill contaminating bacteria without significantly affecting the viability of M. tuberculosis H37Ra. While flow cytometry viability analysis did not directly correspond to viable colony counts, it was a useful tool for rapid viability analysis M. tuberculosis.

A high proportion of novel mycobacteria species identified by 16S rDNA analysis among slowly growing AccuProbe-negative strains in a clinical setting

Sequencing of the 16S ribosomal DNA (rDNA) for identification of nontuberculous mycobacteria (NTM) has contributed to the establishment of more than 35 new species during the last decade. Increasingly, NTM are accepted as potential or proven pathogens. We identified, by 16S rDNA sequence analysis, slowly growing NTM isolates negative by AccuProbe (GenProbe, San Diego, CA) that previously were identified by using conventional biochemical techniques, to determine the accuracy of reporting AccuProbe-negative NTM prior to sequence-based identification. Of 82 strains, 30 were deemed novel. An attempt was made to determine the clinical importance of previously misidentified novel species. Clinical cases are described for a number of strains previously identified as Mycobacterium terrae complex, Mycobacterium scrofulaceum, and Mycobacterium avium complex. As sequence-based identification methods become more commonplace in clinical microbiology laboratories, there is a need to understand the significance of previously undescribed species, which often mimic and subsequently are identified as well-established species.

Soft tissue infection caused by a novel pigmented, rapidly growing mycobacterium species

Molecular techniques are playing an important role in the diagnosis of nontuberculous mycobacterial infections. This case report describes a chronic soft tissue infection in an immunocompetent patient caused by a previously undescribed pigmented, rapidly growing Mycobacterium species, emphasizing the importance of clinical suspicion and effective laboratory techniques in the diagnosis and treatment of infection.

The Genome sequence of the SARS-associated coronavirus

We sequenced the 29,751-base genome of the severe acute respiratory syndrome (SARS)-associated coronavirus known as the Tor2 isolate. The genome sequence reveals that this coronavirus is only moderately related to other known coronaviruses, including two human coronaviruses, HCoV-OC43 and HCoV-229E. Phylogenetic analysis of the predicted viral proteins indicates that the virus does not closely resemble any of the three previously known groups of coronaviruses. The genome sequence will aid in the diagnosis of SARS virus infection in humans and potential animal hosts (using polymerase chain reaction and immunological tests), in the development of antivirals (including neutralizing antibodies), and in the identification of putative epitopes for vaccine development.

Oral dexamethasone for the treatment of pain in children with acute pharyngitis: a randomized, double-blind, placebo-controlled trial

STUDY OBJECTIVE

We compare oral dexamethasone with placebo for the relief of pain in children with acute pharyngitis.

METHODS

We performed a prospective, randomized, double-blind, placebo-controlled trial of children aged 5 to 16 years who presented to the emergency department with acute pharyngitis. Children rated their pain on a standardized color analog scale and had a rapid streptococcal antigen detection test performed to determine group assignment. Children were randomized to dexamethasone (0.6 mg/kg, maximum dose 10 mg) or placebo. Blinded research assistants called all families daily to determine pain scores until the point of complete pain relief. The primary outcome measures were the time to clinically significant pain relief and the time to complete pain relief.

RESULTS

A total of 184 children were enrolled in the study. There were 85 children in the antigen-positive group, of whom 45 were randomized to dexamethasone and 40 to placebo. In children with group A beta-hemolytic streptococcal pharyngitis, the median time to clinically significant pain relief was 6 hours in the dexamethasone group versus 11.5 hours in the placebo group (P =.02; effect size of 5.5 hours with 95% confidence interval [CI] of 1.0 and 10.0 hours), and the time to complete pain relief was similar (36 hours for placebo versus 40 hours for dexamethasone, P =.86; effect size of 4.0 hours with 95% CI of -9.3 and 17.3 hours) in the placebo group. There were 99 children enrolled in the antigen-negative group, of whom 47 received dexamethasone and 52 received placebo. In this group, the median time to clinically significant pain relief was 13 hours in the dexamethasone group versus 9 hours in the placebo group (P =.32; effect size of 4 hours with 95% CI of -2 and 10 hours), and the time to complete pain relief was similar (48 hours for placebo versus 50 hours for dexamethasone, P =.61; effect size of 2 hours with 95% CI of -11.8 and 15.8 hours).

CONCLUSION

For all children with acute pharyngitis, oral dexamethasone does not decrease the time to onset of clinically significant pain relief or time to complete pain relief. However, in the subset of children with positive antigen detection test results, there is a statistically significant improvement in time to onset of pain relief, but it is of marginal clinical importance.

Identification of a predominant isolate of Mycobacterium tuberculosis using molecular and clinical epidemiology tools and in vitro cytokine responses

BACKGROUND

Tuberculosis (TB) surveillance programs in Canada have established that TB in Canada is becoming a disease of geographically and demographically distinct groups. In 1995, treaty status aboriginals from the province of Manitoba accounted for 46% of the disease burden of this sub-group in Canada. The TB incidence rates are dramatically high in certain reserves of Manitoba and are equivalent to rates in African countries. The objective of our study was to identify prevalent isolates of Mycobacterium tuberculosis in the patient population of Manitoba using molecular epidemiology tools, studying the patient demographics associated with the prevalent strain and studying the in vitro cytokine profiles post-infection with the predominant strain.

METHODS

Molecular typing was performed on all isolates available between 1992 to 1997. A clinical database was generated using patient information from Manitoba. THP-1 cells were infected using strains of M. tuberculosis and cytokine profiles were determined using immunoassays for cytokines IL-1beta, IL-10, IL-12, IFN-gamma and TNF-alpha.

RESULTS

In Manitoba, 24% of the disease burden is due to a particular M. tuberculosis strain (Type1). The strain is common in patients of aboriginal decent and is responsible for at least 87% of these cases. Cytokine assays indicate that the Type1 strain induces comparatively lower titers of IL-1beta, IFN-gamma and TNF-alpha in infected THP-1 cells as compared to H37Ra and H37Rv strains.

CONCLUSION

In Manitoba, Type1 strain is predominant in TB patients. The majority of the cases infected with this particular strain are newly active with a high incidence of respiratory disease, positive chest radiographs and pulmonary cavities. In vitro secretion of IL-1beta, IFN-gamma and TNF-alpha is suppressed in Type1 infected culture samples when compared to H37Ra and H37Rv infected cells.

Conventional methods versus 16S ribosomal DNA sequencing for identification of nontuberculous mycobacteria: cost analysis

The clinical profile of nontuberculous mycobacteria (NTM) has been raised by the human immunodeficiency virus and AIDS pandemic. Different laboratory techniques, often molecular based, are available to facilitate the rapid and accurate identification of NTM. The expense of these advanced techniques has been questioned. At the National Reference Center for Mycobacteriology and the Health Sciences Center, University of Manitoba, in Winnipeg, Canada, we performed a direct cost analysis of laboratory techniques for commercial DNA probe-negative (Gen-Probe, Inc., San Diego, Calif.), difficult-to-identify NTM. We compared the costs associated with conventional phenotypic methodology (biochemical testing, pigment production, growth, and colony characteristics) and genotypic methodology (16S ribosomal DNA [rDNA] sequence-based identification). We revealed a higher cost per sample with conventional methods, and this cost varied with organism characteristics: $80.93 for slowly growing, biochemically active NTM; $173.23 for slowly growing, biochemically inert NTM; and $129.40 for rapidly growing NTM. The cost per sample using 16S rDNA sequencing was $47.91 irrespective of organism characteristics, less than one-third of the expense associated with phenotypic identification of biochemically inert, slow growers. Starting with a pure culture, the turnaround time to species identification is 1 to 2 days for 16S rDNA sequencing compared to 2 to 6 weeks for biochemical testing. The accuracy of results comparing both methodologies is briefly discussed. 16S rDNA sequencing provides a cost-effective alternative in the identification of clinically relevant forms of probe-negative NTM. This concept is not only useful in mycobacteriology but also is highly applicable in other areas of clinical microbiology.

Mycobacterium lacus sp. nov., a novel slowly growing, non-chromogenic clinical isolate

A strain of a novel non-chromogenic mycobacterium was isolated from synovial tissue from a 68-year-old female with bursitis of her right elbow. The slowly growing strain had a unique PCR-restriction enzyme analysis (PRA) profile of the hsp65 gene and 16S rRNA gene sequence in comparison with other mycobacterium species. The most closely related species, as determined by 16S rRNA gene sequence analysis, are Mycobacterium malmoense, Mycobacterium marinum, Mycobacterium ulcerans and members of the Mycobacterium tuberculosis complex. The HPLC and biochemical profiles resembled those of Mycobacterium gastri, although differences were noted in the peak-height ratio of the HPLC pattern and the nitrate and pyrazinamidase tests. On the basis of PRA, HPLC, biochemical and 16S rRNA gene sequence analyses, the name Mycobacterium lacus sp. nov. is proposed for this potential pathogen. The type strain is strain NRCM 00-255(T) (= ATCC BAA-323(T) = DSM 44577(T)).

Phenotypic and molecular characterization of clinical isolates of Mycobacterium elephantis from human specimens

Eleven strains of a rapidly growing mycobacterium were isolated from patient specimens originating from various regions of the province of Ontario, Canada, over a 2-year period. Unique high-performance liquid chromatography (HPLC) and PCR-restriction enzyme pattern analysis (PRA) profiles initially suggested a new Mycobacterium species, while sequencing of the 16S rRNA gene revealed a sequence match with Mycobacterium sp. strain MCRO 17 (GenBank accession no. X93028), an isolate determined to be unique which is to date uncharacterized, and also a close similarity to M. elephantis (GenBank accession no. AJ010747), with six base pair variations. A complete biochemical profile of these isolates revealed a species of mycobacteria with phenotypic characteristics similar to those of M. flavescens. HPLC, PRA, and 16S rRNA sequencing of strain M. elephantis DSM 44368(T) and result comparisons with the clinical isolates revealed that these strains were in fact M. elephantis, a newly described species isolated from an elephant. All strains were isolated from human samples, 10 from sputum and 1 from an axillary lymph node.

Necessity of quality-controlled 16S rRNA gene sequence databases: identifying nontuberculous Mycobacterium species

The use of the 16S rRNA gene for identification of nontuberculous mycobacteria (NTM) provides a faster and better ability to accurately identify them in addition to contributing significantly in the discovery of new species. Despite their associated problems, many rely on the use of public sequence databases for sequence comparisons. To best evaluate the taxonomic status of NTM species submitted to our reference laboratory, we have created a 16S rRNA sequence database by sequencing 121 American Type Culture Collection strains encompassing 92 species of mycobacteria, and have also included chosen unique mycobacterial sequences from public sequence repositories. In addition, the Ribosomal Differentiation of Medical Microorganisms (RIDOM) service has made freely available on the Internet mycobacterial identification by 16S rRNA analysis. We have evaluated 122 clinical NTM species using our database, comparing >1,400 bp of the 16S gene, and the RIDOM database, comparing approximately 440 bp. The breakdown of analysis was as follows: 61 strains had a sequence with 100% similarity to the type strain of an established species, 19 strains showed a 1- to 5-bp divergence from an established species, 11 strains had sequences corresponding to uncharacterized strain sequences in public databases, and 31 strains represented unique sequences. Our experience with analysis of the 16S rRNA gene of patient strains has shown that clear-cut results are not the rule. As many clinical, research, and environmental laboratories currently employ 16S-based identification of bacteria, including mycobacteria, a freely available quality-controlled database such as that provided by RIDOM is essential to accurately identify species or detect true sequence variations leading to the discovery of new species.

Mycobacterium branderi from both a hand infection and a case of pulmonary disease

Mycobacterium branderi, a potential human pathogen first characterized in 1995, has been isolated from respiratory tract specimens. We report here a case in which M. branderi was the only organism isolated upon culture from a hand infection. This isolate, along with a second isolate from a bronchial specimen, was subjected to conventional identification tests for mycobacterial species. Further analysis by high-performance liquid chromatography (HPLC) of mycolic acids and 16S rRNA gene sequencing was performed, and the antibiotic susceptibility profile was determined for both strains. Biochemical tests and the HPLC pattern were consistent with that of M. branderi and M. celatum, which are very similar. The 16S rRNA gene sequence of both strains corresponded to that of M. branderi and enabled us to confidently differentiate this organism from other closely related species such as M. celatum. This contributes to a further understanding of the status of this species as a potential human pathogen as well as illustrating the need for molecular diagnostics as a complementary method for the identification of rare mycobacterial species.

Characterization of a toxin A-negative, toxin B-positive strain of Clostridium difficile responsible for a nosocomial outbreak of Clostridium difficile-associated diarrhea

Clostridium difficile-associated diarrhea (CAD) is a very common nosocomial infection that contributes significantly to patient morbidity and mortality as well as to the cost of hospitalization. Previously, strains of toxin A-negative, toxin B-positive C. difficile were not thought to be associated with clinically significant disease. This study reports the characterization of a toxin A-negative, toxin B-positive strain of C. difficile that was responsible for a recently described nosocomial outbreak of CAD. Analysis of the seven patient isolates from the outbreak by pulsed-field gel electrophoresis indicated that this outbreak was due to transmission of a single strain of C. difficile. Our characterization of this strain (HSC98) has demonstrated that the toxin A gene lacks 1.8 kb from the carboxy repetitive oligopeptide (CROP) region but apparently has no other major deletions from other regions of the toxin A or toxin B gene. The remaining 1.3-kb fragment of the toxin A CROP region from strain HSC98 showed 98% sequence homology with strain 1470, previously reported by M. Weidmann in 1997 (GenBank accession number Y12616), suggesting that HSC98 is toxinotype VIII. The HSC98 strain infecting patients involved in this outbreak produced the full spectrum of clinical illness usually associated with C. difficile-associated disease. This pathogenic spectrum was manifest despite the inability of this strain to alter tight junctions as determined by using in vitro tissue culture testing, which suggested that no functional toxin A was produced by this strain.

Helicobacter pylori in the Canadian arctic: seroprevalence and detection in community water samples

OBJECTIVE

Many North American arctic communities are characterized by risk markers associated with Helicobacter pylori (H. pylori) infection, including overcrowded housing and inadequate water supply and sanitation systems. Our aim was to determine the seroprevalence of H. pylori infection in two traditional Inuit communities in the central Canadian arctic and to test for the presence of H. pylori, by polymerase chain reaction (PCR), in local water supplies.

METHODS

Samples of venous whole blood from adults and capillary blood from children were collected and analyzed by enzyme immunoassay and Helisal Rapid Test, respectively, for IgG antibody to H. pylori. Antibodies to CagA were detected by enzyme immunoassay, and ABO and Lewis antigens were also determined. Demographic and clinical information were collected by questionnaire. Water samples from each community were tested for H. pylori by PCR.

RESULTS

One hundred-thirty (50.8%) of 256 subjects from the two communities were positive for H. pylori IgG antibodies. Seropositive subjects were more likely to be male, compared with seronegative individuals (p = 0.01). Antibody status did not differ with respect to age, community, alcohol or cigarette use, number of persons per household, gastrointestinal complaints or previous investigations, medications, or presence of blood group O, Lewis a-b+. CagA antibodies were detected in 78 (61.9%) of 126 H. pylori-seropositive subjects tested; however, 41 (35.3%) of 116 H. pylori-seronegative subjects were also CagA positive. Water samples taken from the water delivery truck in Chesterfield Inlet and two lakes near Repulse Bay were positive for H. pylori.

CONCLUSION

The seroprevalence of H. pylori in the study group was higher than rates in southern Canadian populations, but lower than the seroprevalence previously documented in a Canadian subarctic Indian (First Nations) community. The detection of H. pylori in local water supplies may indicate a natural reservoir for the organism or possible contamination from human sewage.

Seroprevalence of Helicobacter pylori, incidence of gastric cancer, and peptic ulcer-associated hospitalizations in a Canadian Indian population

The living conditions of many aboriginal communities in Canada may place their residents at risk for H. pylori infection. Our aims were to determine: (1) the seroprevalence of H. pylori in a traditional Indian community, (2) the clinical relevance of H. pylori infection in this population, and (3) if H. pylori could be identified by polymerase chain reaction from the local water. A demographic questionnaire was administered, and blood was collected from subjects in an Indian community in northwestern Manitoba. The serum was analyzed by ELISA for IgG to H. pylori and to CagA. ABO and Lewis antigens were tested. Age-adjusted incidence of gastric cancer and of hospitalizations associated with diagnoses of peptic ulcer were determined for the Indian and non-Indian Manitoba population in the years 1989-1993. Nested PCR was performed on lake water using H. pylori-specific primers and the amplicons probed with an internal Dig-labeled probe. Three hundred six (59%) of approximately 518 individuals who were resident in the community at the time of the study were enrolled. The ELISA for H. pylori was positive in 291 (95%). There was no association between H. pylori seropositivity and age, sex, gastrointestinal complaints, medications, housing characteristics, and ABO or Lewis antigen status. CagA was positive in 84.5% of infected subjects. The average annual age-adjusted incidence of hospitalizations associated with diagnoses of peptic ulcer disease in Manitoba was higher for treaty-status Indians (394.3/100,000) than for non-Indians (203.8/100,000), but gastric cancer rates were similar (11.2/100,000 vs 11.6/100,000). No H. pylori DNA was detected in the lake water. In conclusion, the seroprevalence of CagA-positive H. pylori is high in this representative Manitoban Indian community. This may be associated with an increased risk for peptic ulcer disease but is not associated with an increased risk for gastric cancer.

Regional dissemination and control of epidemic methicillin-resistant Staphylococcus aureus. Manitoba Chapter of CHICA-Canada

A methicillin-resistant Staphylococcus aureus (MRSA) strain introduced into the largest tertiary-care teaching hospital in Manitoba in 1993 led to a sustained outbreak with secondary outbreaks at one community hospital, two large long-term-care facilities, and nosocomial transmission at a second teaching hospital. Control measures were consistent at each institution and were coordinated on a province-wide basis. MRSA is not currently endemic in any facility in the province.

M. tuberculosis molecular variation in CNS infection: evidence for strain-dependent neurovirulence

OBJECTIVE

To determine the molecular diversity among Mycobacterium tuberculosis isolates associated with central nervous system tuberculosis (CNS TB) in a defined cohort of HIV uninfected patients.

DESIGN/METHODS

A retrospective analysis was performed of clinical and laboratory data for all patients with CNS TB diagnosed in Manitoba, Canada, between 1979 and 1996. Restriction fragment-length polymorphisms (RFLP) of archival isolates of M. tuberculosis from CNS TB patients were determined and interpreted against the frequency of different isolates from all TB patients in the years 1992 to 1996.

RESULTS

Among 2,334 patients with active TB, CNS TB was diagnosed in 42 (1.8%); meningitis with or without tuberculoma in 76%; and tuberculoma alone in 24%. CNS TB patients were significantly more likely to be young (<40 years old), female, and of Aboriginal origin. Morbidity (fixed/recurrent CNS deficit) rate was 29% and mortality rate was 26%. An adverse outcome, either morbidity or mortality, was significantly more common in those with meningitis. RFLP analysis of isolates (n=19) from CNS TB patients revealed 13 distinct restriction patterns with a predominance of the type 1 pattern (n=6). The frequency of type 1 restriction pattern was significantly greater in patients with CNS TB compared to all TB patients in Manitoba.

CONCLUSIONS

CNS TB continues to have a high morbidity and mortality despite modern methods of detection and treatment. Although several strains of M. tuberculosis cause CNS TB, the current study suggests that the occurrence of CNS TB may be strain-dependent.

Once versus thrice daily tobramycin alone and in combination with ceftazidime, ciprofloxacin and imipenem in an in vitro pharmacodynamic model

The purpose of this study was to compare once daily (To24) and thrice daily (To8) tobramycin dosing regimens alone and in combination with ceftazidime, ciprofloxacin and imipenem against a clinical and ATCC strain of Pseudomonas aeruginosa. A one-compartment in vitro pharmacodynamic model was used to simulate bacteremic infection. Pharmacodynamic parameters, including rate of bacterial kill following the first dose or time to achieve a 99.9% reduction in bacterial counts (T99.9%), extent of bacterial kill with subsequent doses and bacterial count at 24 h were characterized for each regimen. Compared to To8 alone, the combination regimens had a shorter T99.9% (p = 0.045) and greater extent of bacterial kill following the first dose (p = 0.045). Compared to To24 alone, the combination regimens demonstrated similar rates (p = 0.067) and extents of bacterial kill following the first dose (p = 0.32), however, produced lower bacterial counts at 24 h (p = 0.045). The various combination regimens appeared equally effective considering rate and extent of bacterial kill following the first dose and residual inocula at 24 h. Ciprofloxacin-containing regimens demonstrated the most bacterial kill with subsequent doses, however, bacterial counts at 24 h were similar to those of other combination regimens.

In vitro kill curves of a new semisynthetic echinocandin, LY-303366, against fluconazole-sensitive and -resistant Candida species

In vitro killing by a new semisynthetic echinocandin, LY-303366, was characterized using clinical isolates of fluconazole-sensitive (Y58) and -resistant (Y180) Candida albicans as well as Candida glabrata (Y7) and Candida krusei (Y171). The 24-h kill curves for Y58 and Y180 demonstrated dose-independent killing of between 1 and 2 log10 with LY-303366 at concentrations of 0.1, 1, 10, 50, 100, and 1,000 times the MIC. Regrowth did not occur at 24 h with either C. albicans isolate at the aforementioned LY-303366 concentrations. At their MICs, LY-303366 and amphotericin B produced similar killing kinetics in cultures of Y58, Y180, Y7, and Y171, while all cultures exposed to fluconazole at its MIC demonstrated stasis or growth over 24 h.

Rapid geographic spread of a methicillin-resistant Staphylococcus aureus strain

In May 1993, an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) was identified at our tertiary care teaching center. The epidemic MRSA strain was transmitted efficiently in the hospital environment. Subsequent investigations indicated that the strain had been introduced into western Canada by a patient who had recently been hospitalized for 3 months in the Punjab, India, and had been admitted to a hospital in rural British Columbia shortly after his arrival in Canada. Transfer of the patient to a hospital in Vancouver and subsequent transfer of a colonized patient contact to a hospital in Winnipeg, Manitoba, resulted in major outbreaks of MRSA at these two large tertiary care centers within 6 weeks of the arrival of the index case in Canada. Epidemiological typing of the S. aureus coagulase gene with use of a polymerase chain reaction method and pulsed-field gel electrophoresis documented clonality of this strain. These outbreaks again illustrate both the propensity of certain strains of S. aureus to produce epidemic disease, including rapid spread within the institutional setting, and the global nature of problems with antimicrobial resistance.

In vitro activity of a new semisynthetic echinocandin, LY-303366, against systemic isolates of Candida species, Cryptococcus neoformans, Blastomyces dermatitidis, and Aspergillus species

The in vitro activities of LY-303366, a new semisynthetic echinocandin, and comparators amphotericin B, 5-fluorocytosine, fluconazole, and ketoconazole against 205 systemic isolates of Candida species, Cryptococcus neoformans, Blastomyces dermatitidis, and Aspergillus species were determined. LY-303366 had MICs of < or = 0.32 microg/ml for all Candida albicans (n = 99), Candida glabrata (n = 18), and Candida tropicalis (n = 10) isolates tested. LY-303366 was also active against Aspergillus species (minimum effective concentration at which 90% of the isolates are inhibited, 0.02 microg/ml) (n = 20), was less active against Candida parapsilosis (MIC at which 90% of the isolates are inhibited [MIC90], 5.12 microg/ml) (n = 10), and was inactive against C. neoformans (MIC90, >10.24 microg/ml) (n = 15) and B. dermatitidis (MIC90, 16 microg/ml) (n = 29).

Production and characterization of chimeric transferrins for the determination of the binding domains for bacterial transferrin receptors

Pathogenic bacteria in the Neisseriaceae and Pasteurellaceae possess outer membrane proteins that specifically bind transferrin from the host as the first step in the iron acquisition process. As a logical progression from prior studies of the ligand-receptor interaction using biochemical approaches, we have initiated an approach involving the production of recombinant chimeric transferrins to further identify the regions of transferrin involved in receptor binding. In order to prepare bovine/human hybrids, the bovine transferrin gene was cloned, sequenced, and compared with the existing human transferrin gene sequence. After identification of potential splice sites, hybrid transferrin genes were constructed using the polymerase chain reaction-based approach of splicing by overlap extension. Five hybrid genes containing sequences from both bovine and human transferrin were constructed. Recombinant transferrins were produced in a baculovirus expression vector system and affinity-purified using concanavalin A-Sepharose. The recombinant proteins were analyzed for reactivity against polyclonal and monoclonal antibodies and assessed for binding to Neisseria meningitidis transferrin receptor proteins in solid-phase binding assays and affinity isolation experiments. These experiments enabled us to localize the regions of human transferrin predominantly involved in binding to the N. meningitidis receptor to amino acid residues 346-588. The construction of these chimeras provides unique tools for the investigation of transferrin binding to receptors from both human and bovine bacterial pathogens.

Practice guidelines for ordering stool ova and parasite testing in a pediatric population. The Alberta Children's Hospital

A comprehensive utilization review was done of all stool ova parasite examinations performed at a pediatric hospital during a 3-year period from June 1, 1989 to July 1, 1992. A total of 2,652 stool specimens were surveyed from 1,532 children. Forty-one percent (1,081) of the workload was from inpatients, 37% (976) was from emergency room (ER) visits/other outpatients, and 22% (233) was from patients attending the gastroenterology (GI) clinic. The prevalence of enteric parasites in hospitalized children was 4% (35 of 829) compared to rates of 10% (47 of 470) and 13% (30 of 233) for children attending the ER/other outpatient clinics and GI clinic, respectively. Giardia lamblia was found most often (31%[45 of 146]), followed by Dientamoeba fragilis (23%[33 of 146]), Entamoeba coli (16%[24 of 146]), Blastocystis hominis (13% [19 of 146]), Cryptosporidium (8% [12 of 146]), Endolimax nana (4% [6 of 146]), Enterobius vermicularis (2% [3 of 146]), Hymenolepis nana (2% [3 of 146]), and Iodamoeba buetschlii (1% [1 of 146]). Most children were colonized/infected with a single parasite (85%) with a much smaller number having two or more parasites. Only nine children (6%) who were immunocompetent and hospitalized for more than 4 days were found to have enteric parasites. Over the past 18 months, significant sustainable cost savings have resulted from the implementation of practice guidelines for ordering pediatric stool ova and parasite examinations.

Atypical and complicated Kawasaki disease in infants. Do we need criteria?

Case reports suggest that infants with Kawasaki disease have atypical presentations and a high complication rate, likely related to delayed diagnosis and treatment. To date, no study of consecutive cases has compared infants with older children who have both atypical and typical Kawasaki disease. We retrospectively reviewed 44 cases of Kawasaki disease treated at our hospital from March 1980 to 1990: 11 (25%) were infants; 9 (20%) had atypical Kawasaki disease, of which 5 (56%) were infants; the male to female ratio was 1.7:1. Infants had a higher incidence of atypical Kawasaki disease (5 [45%] versus 4 [12%]; P = .007) and of coronary artery complications (7 [64%] versus 3 [9%]; P = .002), and coronary artery complications developed in all of the infants with atypical Kawasaki disease (5 [100%] versus 0 [0%]; P < .01). Yet, the other manifestations and laboratory changes were at least as common as in the older children. Coronary artery complications did not develop in any patient who received early intravenous immune globulin therapy. We suggest that in infants with Kawasaki disease, accepted criteria are too restrictive to allow early diagnosis and effective treatment. Until a definitive test is available, clinical judgment is required in the diagnosis of atypical Kawasaki disease. Intravenous immune globulin is known to be safe, and its early use in patients with suspected atypical Kawasaki disease is appropriate.

Practice guidelines for ordering stool cultures in a pediatric population. Alberta Children's Hospital, Calgary, Alberta, Canada

A comprehensive utilization review was done of all stool culture tests performed at a pediatric hospital during a 3-year period from June 1, 1989 through to July 1, 1992. A total of 4,460 stool culture specimens were surveyed from 3,420 children. Sixty percent (2,692) of the workload was from inpatients, 22% (1,001) was from emergency room (ER) visits and 18% (767) was from outpatient clinic/office visits. A total of 9% (294 of 3,420) of the children were confirmed to have enteric bacterial infection. Enteric infections in Southern Alberta follow a typical pattern, where most cases of Escherichia coli O157:H7, Salmonella sp and Campylobacter jejuni are diagnosed in the summer months between June and September. Marked differences were found in the overall stool culture positivity rate between hospitalized children (94 of 2,141, 4%), and ambulatory children attending the ER (176 of 892, 19%). Although a significant number of children had more than one stool culture done, most cases of enteric bacterial infections were diagnosed on the first stool sample (290 of 294, 98%). Most children (89 of 94, 95%) who were hospitalized because of an acute diarrheal illness had a bacteriological diagnosis confirmed within the first 4 days after admission (90 of 94, 96%), including immunocompromised children in the Oncology ward. Over the past year, significant sustainable cost savings have resulted from the implementation of practice guidelines for ordering pediatric stool cultures.