Amin Kabani

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

OBJECTIVES: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.

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.

Candidemia in a Canadian tertiary care hospital from 1976 to 1996

The incidence of candidemia was reviewed at the Health Sciences Centre in Winnipeg, Canada, over a 21-year period (1976 to 1996). Candida species were identified as blood-stream isolates in significantly (p < 0.05) higher numbers from 1991 to 1996 than in the previous 15 years. Antifungal susceptibilities remained unchanged with Candida albicans isolates tested from 1985 to 1996. Retrospective chart reviews revealed that all patients with candidemia possessed at least two risk factors. The main risk factors identified were recent or concurrent antibiotic therapy (95% of patients), presence of a central line (93% of patients), and immunosuppression (88% of patients). Treatment generally involved amphotericin B therapy (81% of patients), and death occurred in 52% of the patients. Mortality directly attributable to Candida species could be established in 23% of patients.

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

Abstract 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 103mAbs 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.

Seroprevalence of Helicobacter pylori, Incidence of Gastric Cancer, and Peptic Ulcer-Associated Hospitalizations in a Canadian Indian Population

The living conditions of many aboriginalcommunities in Canada may place their residents at riskfor H. pylori infection. Our aims were to determine: (1)the seroprevalence of H. pylori in a traditional Indian community, (2) the clinical relevance ofH. pylori infection in this population, and (3) if H.pylori could be identified by polymerase chain reactionfrom the local water. A demographic questionnaire was administered, and blood was collected fromsubjects in an Indian community in northwesternManitoba. 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 ofhospitalizations associated with diagnoses of pepticulcer were determined for the Indian and non-IndianManitoba population in the years 1989-1993. Nested PCR was performed on lake water using H.pylori-specific primers and the amplicons probed with aninternal Dig-labeled probe. Three hundred six (59%) ofapproximately 518 individuals who were resident in the community at the time of the study wereenrolled. The ELISA for H. pylori was positive in 291(95%). There was no association between H. pyloriseropositivity and age, sex, gastrointestinalcomplaints, medications, housing characteristics, and ABOor Lewis antigen status. CagA was positive in 84.5% ofinfected subjects. The average annual age-adjustedincidence of hospitalizations associated with diagnoses of peptic ulcer disease in Manitoba was higherfor treaty-status Indians (394.3/100,000) than fornon-Indians (203.8/100,000), but gastric cancer rateswere similar (11.2/100,000 vs 11.6/ 100,000). No H. pylori DNA was detected in the lake water. Inconclusion, the seroprevalence of CagA-positive H.pylori is high in this representative Manitoban Indiancommunity. This may be associated with an increased risk for peptic ulcer disease but is notassociated with an increased risk for gastriccancer.

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.

Conventional and molecular epidemiology of Tuberculosis in Manitoba

BackgroundTo describe the demographic and geographic distribution of tuberculosis (TB) in Manitoba, thus determining risk factors associated with clustering and higher incidence rates in distinct subpopulations.MethodsData from the Manitoba TB Registry was compiled to generate a database on 855 patients with tuberculosis and their contacts from 1992–1999. Recovered isolates of M. tuberculosis were typed by IS6110 restriction fragment length polymorphisms. Bivariate and multivariate logistic regression models were used to identify risk factors involved in clustering.ResultsA trend to clustering was observed among the Canadian-born treaty Aboriginal subgroup in contrast to the foreign-born. The dominant type, designated fingerprint type 1, accounts for 25.8% of total cases and 75.3% of treaty Aboriginal cases. Among type 1 patients residing in urban areas, 98.9% lived in Winnipeg. In rural areas, 92.8% lived on Aboriginal reserves. Statistical models revealed that significant risk factors for acquiring clustered tuberculosis are gender, age, ethnic origin and residence. Those at increased risk are: males (p < 0.05); those under age 65 (p < 0.01 for each age subgroup); treaty Aboriginals (p < 0.001), and those living on reserve land (p < 0.001).ConclusionMolecular typing of isolates in conjunction with contact tracing data supports the notion of the largest ongoing transmission of a single strain of TB within the treaty-status population of Canada recorded to date. This data demonstrates the necessity of continued surveillance of countries with low prevalence of the disease in order to determine and target high-risk populations for concentrated prevention and control measures.

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

BackgroundTuberculosis (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.MethodsMolecular typing was performed on all isolates available between 1992 to1997. 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-1β, IL-10, IL-12, IFN-γ and TNF-α.ResultsIn 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-1β, IFN-γ and TNF-α in infected THP-1 cells as compared to H37Ra and H37Rv strains.ConclusionIn 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-1β, IFN-γ and TNF-α is suppressed in Type1 infected culture samples when compared to H37Ra and H37Rv infected cells.

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 childrens 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.

In vitro antifungal activity of BMS-181184 against systemic isolates of Candida, Cryptococcus, and Blastomyces species

BMS-181184 is a water-soluble derivative of the pradimicin group of antifungal compounds. We determined the in vitro activities of BMS-181184 and comparator agents amphotericin B, 5-fluorocytosine, fluconazole, and ketoconazole against 184 systemic fungal isolates collected at the Health Sciences Centre in Winnipeg, Canada, between 1987 and 1995. BMS-181184 demonstrated MICs of between 1 and 8 micrograms/mL for all Candida albicans, Candida glabrata, Candida tropicalis, Candida krusei, Candida lusitaniae, and Cryptococcus neoformans isolates tested. BMS-181184 was less active against Candida parapsilosis (MIC90 = 16 micrograms/mL) and Blastomyces dermatitidis (MIC90 = 32 micrograms/mL). Isolates of Candida species with fluconazole MICs of > or = 16 micrograms/mL and those with fluconazole MICs of < or = 8 micrograms/mL demonstrated similar BMS-181184 sensitivities.