Improving access to care by allowing self-referral to a hepatitis C clinic.

BACKGROUND: Estimates suggest that more than 250,000 Canadians are infected with hepatitis C virus (HCV), but less than 10% have been treated. Access to specialists in Canada is usually via health care professional (HCP) referral and, therefore, may be a barrier to HCV care. However, clinics that operate in conjunction with the Hepatitis Support Program, Edmonton, Alberta, allow self-referral. It is hypothesized that this improves access to care without increasing inappropriate referrals. OBJECTIVE: To compare the baseline characteristics and outcomes of HCV patients who self-referred with those who were HCP-referred. METHODS: Data were collected from the Hepatitis Support Program HCV database and chart reviews. RESULTS: Between December 17, 2002, and December 31, 2007, 1563 patients were referred including 336 self- (21.5%) and 1227 HCP-referrals (78.5%). Self- and HCP-referred patients were similar in terms of age (mean [+/- SD] 43.0+/-10.3 years versus 43.9+/-10.0 years, respectively; P=0.18), sex (56.8% versus 62.0% [men], respectively; P=0.08) and risk factors for HCV (P=0.3), with 49.7% and 52.6%, respectively, identifying injection drug use as the primary risk factor. The two groups had similar HCV genotype distributions and liver biopsy fibrosis scores with similar treatment rates (31.3% versus 33.2%; P=0.6). Treatment outcomes were excellent (sustained virological response 40.2% for genotype 1, 67% for genotypes 2 and 3) in patients completing therapy and were similar between the two groups. CONCLUSION: Self-referred patients comprised 21.5% of patients accessing care in the clinic. Self- and HCP-referred patients had similar characteristics, treatment rates and outcomes. Facilitating self referral to an HCV clinic can improve access to care, including risk reduction education and HCV treatment.

Mycobacterium chimaera Infection After Aortic Valve Replacement Presenting With Aortic Dissection and Pseudoaneurysm.

We present a case of Mycobacterium chimaera infection presenting with aortic dissection and pseudoaneuysm in a 22-year-old man with a past history of aortic valve replacement. Clinicians should consider M. chimaera infection in those presenting with aortic dissection as a late complication of cardiovascular surgery.

Purification, crystallization and preliminary X-ray analysis of murine interleukin-5.

Wild-type and mutant forms of murine interleukin-5 (mIL-5) have been expressed in the baculovirus expression system, purified, and used in crystallization trials. Attempts to obtain diffraction quality crystals of wild-type protein were unsuccessful. The substitution of glutamine for Asn75 preserved biological activity, while removing one of two predicted N-linked glycosylation sites, and the resulting protein was crystallized from polyethylene glycol 8000 at pH 7.8 in two crystal forms. The orthorhombic crystals, which belong to space group P2(1)2(1)2 with cell dimensions a = 55.9 A, b = 83.0 A and c = 52.3 A, diffract to beyond 2.5 A resolution. The second crystal form belongs to a trigonal space group, either P3(1)21 or P3(2)21, with cell dimensions a = b = 62.1 A, c = 129.9 A, and diffracts to about 3.8 A resolution. Each crystal form probably contains one mIL-5 dimer per asymmetric unit.

Molecular analysis of membrane gamma 2b heavy chain expression.

In order to study T cell regulation of B cell isotype differentiation we have developed a model system consisting of clonal populations of T and B cells. Using this system we have shown that the murine B cell lymphoma, 70Z/3, can be induced to express membrane IgG2b by exposure to a T cell hybridoma derived from the Peyer's patch (termed HAJ-3). The membrane bound IgG2b (mIgG2b) expression is associated with induction of gamma 2b-mRNA, but switch region rearrangement and C mu deletion does not occur. While LPS-stimulated 70Z/3 B cells also express considerable amounts of gamma 2b-mRNA they do not express detectable mIgG2b, indicating that T cell influence is necessary for the production of translatable gamma 2b-specific mRNA. Both the LPS and T cell induced gamma 2b mRNA transcripts lack VH sequences, implying that the surface IgG2b detected lacks a variable region. These findings lend support to a two step model of B cell isotype switching and provide evidence that T cells can regulate early events involved in B cell isotype differentiation.

Serum drug concentrations of INH and RMP predict 2-month sputum culture results in tuberculosis patients.

BACKGROUND: In Alberta provincial tuberculosis (TB) clinics, serum drug concentrations (SDCs) are measured in patients with human immunodeficiency virus, diabetes mellitus or at extremes of weight, or showing slow clinical response to treatment, to guide treatment. DESIGN: A retrospective review was performed of TB cases in Northern Alberta with SDCs measured from 1998 to 2013. Adequacy of SDC was based on the maximum concentration (Cmax) achieved in serum, with rifampicin (RMP) values <8 µg/ml and isoniazid (INH) values <3 µg/ml for daily dosing and <9 µg/ml for intermittent dosing considered inadequate. Clinical variables and microbiological outcomes were then compared between the adequate and inadequate groups. RESULTS: Of 134 pulmonary TB cases with SDCs for INH and/or RMP, we found a significant increase in 2-month sputum culture positivity in the cohort with inadequate concentrations of INH compared to those with adequate INH concentrations (42.5% vs. 18.3%, P = 0.0084). A similar trend was seen in the cohort with inadequate concentrations of RMP (39% vs. 21%, P = 0.0725). CONCLUSIONS: Among our study population, low SDCs of INH and, to a lesser extent, RMP, appear to be associated with reduced sputum culture conversion after 2 months of treatment.

Severe hepatotoxicity associated with rifampin-pyrazinamide preventative therapy requiring transplantation in an individual at low risk for hepatotoxicity.

We report a case of severe hepatotoxicity associated with rifampin-pyrazinamide preventative therapy that required liver transplantation in a closely monitored, human immunodeficiency virus-uninfected individual who had no risk for hepatotoxicity. Because hepatotoxicity associated with this treatment appears to be idiosyncratic, we recommend closer monitoring of liver enzyme levels than do the Centers for Disease Control and Prevention guidelines, as well as at least temporary interruption of treatment during any elevation of liver enzyme levels greater than the normal value.

Early steps of IgA B cell differentiation.

The overall picture of IgA B cell differentiation to emerge from these studies is that sIgM-bearing 'virgin' B cells entering the Peyer's patches are subject to a microenvironment (most probably organ-specific stromal cells) which brings about initial or primary IgA switch differentiation. For reasons mentioned, this probably does not involve TGF-beta, which instead appears to operate on a cell, such as the CH12.LX B cell, which has already undergone the initial steps of IgA isotype switching. The next stage of IgA B cell differentiation involves a cell which expressed both sIgM and sIgA simultaneously and appears to produce C mu and C alpha mRNA transcripts in the absence of a deletional rearrangement. Whether this involves a 'transplicing' mechanism or some other mechanism has yet to be determined. Finally, committed IgA B cells emerge from the dual-bearing cell population which express only sIgA. These cells can migrate out of Peyer's patches and respond to various terminal differentiation factors such as IL-5, IL-6 and IFN-gamma.

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.

Immunization of BALB/c mice with mIFN-gamma-secreting Mycobacterium bovis BCG provides early protection against Leishmania major infection.

We developed and tested IFN-gamma-expressing Mycobacterium bovis, strain BCG, for the ability to activate macrophages and protect mice against a heterologous challenge with Leishmania major. One, 2 or 3 weeks after intraperitoneal immunization, mice were challenged with 10(6) L. major amastigotes injected into the right footpad. Recombinant BCG immunization for all 3 challenge time points initially showed greater protection compared to the BCG control, as judged by footpad thickness and number of parasites in the leishmanial lesion. However, at week 4 after challenge, while the 1- and 2-week immunization groups continued to show increased protection, the 3-week immunization group animals exhibited progressive disease. These data suggest that the IFN-gamma-expressing BCG initially activates macrophages more effectively than native BCG, but that late exacerbation of disease can occur, highlighting the complexity of the immune response against leishmaniasis.

The emergency department is a determinant point of contact of tuberculosis patients prior to diagnosis.

SETTING: Metropolitan Edmonton, Canada. OBJECTIVES: To determine 1) the pre-diagnosis emergency department utilization history of urban tuberculosis patients, and 2) the resource and outcome implications of emergency department utilization by tuberculosis patients pre-diagnosis. DESIGN: Nested case (emergency department attendee) control (non-emergency department attendee) study of a retrospective cohort of tuberculosis patients. PATIENTS: All tuberculosis notifications, 1994 through 1998. MAIN OUTCOME MEASURES: Emergency department utilization during the 6 months antedating the diagnosis and emergency department attendee characteristics; for those notified in 1997 and 1998, hospitalizations, nosocomial infectiousness time, and health care costs. RESULTS: Of 250 cases of tuberculosis, 117 (47%) made a total of 258 pre-diagnosis emergency department visits. Emergency department use increased the nearer the patient was to diagnosis. Emergency department attendees were more likely to be older, to have smear and/or culture positive respiratory disease, to have a risk factor for progression of infection to disease, and to have a fatal outcome. In 1997 and 1998, emergency department throughput accounted for 70% of all hospitalization days, 95% of all source case nosocomial infectiousness time, and most health care costs of tuberculosis patients pre-diagnosis. CONCLUSIONS: The emergency department is heavily utilized by urban tuberculosis patients pre-diagnosis. Emergency department throughput of tuberculosis patients pre-diagnosis has major resource and outcome implications. The emergency department may present an opportunity for earlier diagnosis.

Investigation of tuberculosis transmission in Canadian Arctic Inuit communities using DNA fingerprinting.

OBJECTIVE: To understand the transmission of tuberculosis in Inuit communities in the Baffin region of the Canadian Arctic. METHODS: Twenty-one isolates of Mycobacterium tuberculosis from 19 Inuit patients diagnosed with tuberculosis between February 1991 and September 1993 were analyzed by DNA fingerprinting. The DNA fingerprints were achieved by the standard restriction fragment length polymorphism (RFLP) technique, with subsequent probing using the repetitive insertion segment IS6110. RESULTS: The isolates could be divided into three DNA types. The DNA types generally corresponded to the geographic origins of the patients. In most instances only one DNA type of M. tuberculosis was identified in each community. This suggests that a single case was the start of each of the three clusters, most likely due to reactivation. CONCLUSIONS: The results show that molecular typing of M. tuberculosis was useful in determining the mode of transmission of tuberculosis in a remote area of the Canadian Arctic where the disease is endemic. In addition, the information provides useful information for planning interventions in this setting.

The molecular epidemiology of tuberculosis in western Canada.

OBJECTIVE: To define the molecular epidemiology of TB in western Canada, and in particular the risk factors for clustering. MEASUREMENTS: We prospectively identified all positive cultures from newly diagnosed cases of TB diagnosed between February 1995 and January 1997 and carried out restriction fragment length polymorphism (RFLP) testing on all isolates. RESULTS: Of 956 cases identified, 944 fulfilled the entry criteria. The mean age was 49.65 years (+/- 22.33), and 508 (53.6%) were males. Three hundred and three (32.1%) subjects were clustered; this varied from 20.2% of the foreign born, 48.4% of Canadian non-Aboriginal and 61.1% of all Aboriginal persons. Younger persons (P = 0.0001), males (P = 0.015), those with pulmonary disease (P < 0.001), living in a shelter in the past year (P < 0.001), drug-susceptible disease (P < 0.036), predisposing factors (P < 0.001), prior contact (P < 0.001), and prior skin test (P < 0.002) were more likely to cluster. Among specific risk factors, HIV infection, injection drug use, alcohol excess, and weight loss were all significant. CONCLUSIONS: In this description of the molecular epidemiology of TB in Western Canada, previous results have been confirmed and extended. These results highlight the importance of identifying specific high risk groups, especially in the context of renewed efforts to target persons for treatment of latent TB infection.

Immune mediated 'HAART' attack during treatment for tuberculosis. Highly active antiretroviral therapy.

Highly active antiretroviral therapy (HAART) suppresses viral replication and improves immune function. However the inflammatory component of immune restoration can have clinically deleterious effects on previously asymptomatic infections. We report the development of acute respiratory failure in a patient after the institution of HAART, following 2 months of appropriate therapy for pulmonary tuberculosis. Necrotizing granulomas with acid-fast bacilli were found on lung biopsy, but cultures were negative for Mycobacterium tuberculosis and no other pathogens were isolated. Polymerase chain reaction of lung biopsy tissue for all mycobacterial species was positive only for M. tuberculosis. Rapid clinical improvement followed corticosteroid therapy. After initiating HAART, clinicians should be aware of the possibility of an inflammatory response to a previously quiescent tuberculous infection, even while on antituberculosis therapy.

The epidemiology of tuberculosis among foreign-born persons in Alberta, Canada, 1989-1998: identification of high risk groups.

BACKGROUND: To date, there have been no comprehensive epidemiological studies in Canada of the incidence rates of tuberculosis among foreign-born persons. Accurate rate estimates are needed to develop cost-effective strategies for the prevention, control, and ultimate elimination of tuberculosis. METHODS: Most new immigrants to Canada settle in one of four provinces: Ontario, British Columbia, Quebec and Alberta. Data from the provincial reporting system for tuberculosis, from Statistics Canada censuses and population estimates of Treaty Status Indians provided by the Department of Indian and Northern Affairs Canada, were used to estimate the rate of tuberculosis in Alberta's Canadian-born and foreign-born population between 1989 and 1998. RESULTS: Age-adjusted tuberculosis case rates per 100,000 person-years were 19.4 and 61.9 in the foreign-born and Canadian-born Treaty Indians-approximately 10 times and 30 times, respectively, higher than the rate in the remainder of the Canadian-born population (2.1/100,000 person-years). Age-specific rates in male and female foreign-born persons were highest at ages 15-34 and > or = 65 years, whereas rates in Canadian-born non-Treaty and Treaty males and females increased incrementally, with a single peak at > or = 65 years. Tuberculosis case rates in the foreign-born varied significantly according to World Bank region and country of birth. By far the highest rates were seen in immigrants to Canada from Asia, in particular Vietnam, the Philippines, China, Hong Kong and India. Most (90%) tuberculosis patients from these countries had not been identified as requiring medical surveillance in Canada after arrival. CONCLUSION: Immigrants to Alberta from Asia and Treaty Status Indians are at high risk for tuberculosis. Physicians in Alberta who care for foreign-born persons should be aware that their patients are at increased risk for tuberculosis, even if they have been medically cleared during the legal immigration process.

Transmission characteristics of tuberculosis in the foreign-born and the Canadian-born populations of Alberta, Canada.

SETTING: All notified cases of tuberculosis in the province of Alberta, Canada, 1994-1998. OBJECTIVE: To compare the transmission characteristics of tuberculosis among foreign-born and Canadian-born cases. DESIGN: Retrospective analysis using DNA fingerprinting (IS6110 restriction fragment length polymorphism and spoligotyping) and patient information from the Alberta Tuberculosis Registry. Transmission indexes were determined by calculating the average number of culture-positive pulmonary cases generated by a single source case. RESULTS: Of the 750 cases of active tuberculosis, 437 (58.3%) were in the foreign-born. DNA fingerprinting of Mycobacterium tuberculosis isolates from all 573 culture-positive cases over the 5 years from 1994 to 1998 showed that there was significantly less clustering among foreign-born isolates (9.8%) compared to Canadian-born non-Aboriginal (28.8%) and Aboriginal (44.7%) isolates. The transmission index was significantly higher for males, lower for those > or =65 years of age, and higher for Aboriginals. CONCLUSION: Although cases of tuberculosis in the foreign-born constitute the majority in Alberta, there is little transmission to other foreign-born or to Canadian-born individuals. Transmission of tuberculosis among the Aboriginal population remains a significant problem in Alberta.

Microbiologic spectrum and susceptibility of isolates: part I. Postoperative endophthalmitis. Endophthalmitis Research Group.

PURPOSE: To present the microbial spectrum and susceptibilities of isolates in postoperative endophthalmitis. METHOD: Isolates from 206 eyes of 206 patients who underwent vitrectomy for postoperative endophthalmitis were examined. RESULTS: One-hundred twelve (54.4%) of 206 vitreous samples were culture positive and 14 (12.5%) of 112 culture-positive cases were polymicrobial, yielding a total of 126 isolates. Isolates included 59 (46.8%) gram-positive cocci, eight (6.3%) gram-positive bacilli, 33 (26.2%) gram-negative organisms, five (4.0%) Actino-mycetes-related organisms, and 21 (16.7%) fungi. Susceptibilities to amikacin, ceftazidime, chloramphenicol, cefazolin, ciprofloxacin, gentamicin, and vancomycin are reported. CONCLUSIONS: This is the largest, single-center, prospective series on microbial susceptibilities in postoperative endophthalmitis. We report a high prevalence of gram-negative species and fungi, suggesting that empiric therapy should include coverage for gram-negative pathogens and for fungal pathogens in appropriate settings.

Microbiologic spectrum and susceptibility of isolates: part II. Posttraumatic endophthalmitis. Endophthalmitis Research Group.

PURPOSE: To present the microbial spectrum and susceptibilities of isolates in posttraumatic endophthalmitis. METHOD: Isolates from 182 eyes of 182 patients who underwent vitrectomy for posttraumatic endophthalmitis were examined. RESULTS: One hundred thirteen (62.1%) of 182 vitreous samples were culture-positive, and 23 (20.4%) of 113 culture-positive cases were polymicrobial, including three (2.7%) trimicrobial cases, yielding a total of 139 isolates. Isolates included 63 (45.3%) gram-positive cocci, 24 (17.3%) gram-positive bacilli, 25 (18.0%) gram-negative organisms, seven (5.0%) Actinomycetes-related organisms, and 20 (14.4%) fungi. Susceptibilities to amikacin, ceftazidime, chloramphenicol, cefazolin, ciprofloxacin, gentamicin, and vancomycin are reported. CONCLUSIONS: This study represents a large series on microbial spectrum and susceptibilities in posttraumatic endophthalmitis. We report a high prevalence of gram-positive bacilli species and polymicrobial infections containing gram-negative species, underscoring the importance of broad-spectrum, combination antibiotics in the empiric treatment of posttraumatic endophthalmitis.

The roles of IL-4, TGF-beta and LPS in IgA switching.

CH12.LX B cells have been used as a lymphoma model of MHC restricted, antigen-dependent B cell differentiation. These B cells express surface IgM and secrete IgM. Most recently we have demonstrated that CH12.LX is a model of cytokine driven IgA differentiation. Recently, transforming growth factor beta (TGF-beta) has been shown to be a probable switch factor for IgA in LPS-stimulated mouse lymphocytes, therefore we chose CH12.LX B cells to study the effect of IL-4, TGF-beta and LPS in IgA isotype switching. Adding TGF-beta to the monoclonal cell line CH12.LX results in induction of mIgA expression but no enhancement of IgA secretion similar to the effect of IL-4. The addition of LPS serves as a non-specific stimulus to enhance the secretion of the expressed immunoglobulin, but has no IgA specific activity of its own. IL-4 and TGF-beta together are synergistic for mIgA expression. Pretreatment studies show that TGF-beta added after IL-4 is the same as TGF-beta alone whereas the converse is the same as adding both cytokines together. TGF-beta acts by increasing the steady state levels of alpha message, whereas northern analysis indicates that IL-4 does not induce alpha message the way TGF-beta does. These data confirm that TGF-beta by itself is an isotype switch factor for IgA. In addition, IL-4 and TGF-beta cause mIgA expression through different mechanisms. CH12.LX B cells serve as a valuable model to study the role of multiple signals required for mIgA expression and IgA secretion.

Corneal ulceration in the elderly in Hyderabad, south India.

AIMS: To report demographic, microbiological, therapeutic, anatomical, and visual results of corneal ulceration in the elderly patients seen at a tertiary eye care centre in south India. METHODS: 102 consecutive cases of microbial keratitis in patients 65 years and older were studied. Inclusion criteria were: (i) presence of corneal stromal infiltrate upon slit lamp examination; and (ii) microbiological evaluation of corneal scrapings for suspected microbial keratitis. RESULTS: The principal predisposing factors identified in this study were ocular disease (38.2%), previous ocular surgery in the same eye (29.4%), trauma (17.6%), and severe systemic disease (16.7%). Contact lens wear was associated with only two cases (2.0%). 99 organisms were isolated in cultures of corneal scrapings from 74 (72.5%) of the 102 cases. Staphylococcus epidermidis (31.1%), filamentous fungi (25.7%), and Streptococcus pneumoniae (13.5%) were the most common isolates. 12 eyes (11.8%) required surgery, 15 (14.7%) eventually required evisceration, and nine (9.6%) of the 94 followed patients achieved an unaided vision of 20/60 or better at last follow up. CONCLUSIONS: This work represents the largest recent single centre study on (non-viral) microbial keratitis in the elderly, its management, and outcomes of therapy. While the predisposing factors differ from those of general population, the spectrum of microbes responsible for keratitis in the elderly appears to reflect the local microbial flora rather than a predilection for elderly patients. Delay in diagnosis and systemic conditions associated with advancing age probably contribute to poorer outcome from therapeutic measures.