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Paquet-Bolduc B, Gervais P, Roussy JF, Trottier S, Oughton M, Brukner I, Longtin J, Loo VG, Dascal A, Longtin Y. Detection and Isolation of Clostridium difficile Asymptomatic Carriers During Clostridium difficile Infection Outbreaks: An Exploratory Study. Clin Infect Dis 2019; 67:1781-1783. [PMID: 29771298 DOI: 10.1093/cid/ciy425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/11/2018] [Indexed: 12/27/2022] Open
Abstract
During 4 Clostridium difficile infection outbreaks, unit-wide screening of 114 patients led to detection and isolation of 15 (13%) C. difficile asymptomatic carriers. Carriage prevalence varied between outbreaks, from 0% to 29% (P = .004). Isolating carriers was not associated with significantly shorter outbreak durations, compared with historical controls.
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Affiliation(s)
| | - Philippe Gervais
- Quebec Heart and Lung Institute, Quebec City, Quebec.,Laval University Faculty of Medicine, Quebec City, Quebec
| | - Jean-Francois Roussy
- Quebec Heart and Lung Institute, Quebec City, Quebec.,Laval University Faculty of Medicine, Quebec City, Quebec
| | - Sylvie Trottier
- Quebec Heart and Lung Institute, Quebec City, Quebec.,Laval University Faculty of Medicine, Quebec City, Quebec
| | - Matthew Oughton
- Jewish General Hospital, Quebec, Canada.,McGill University Faculty of Medicine, Quebec, Canada
| | | | - Jean Longtin
- Laval University Faculty of Medicine, Quebec City, Quebec
| | - Vivian G Loo
- McGill University Faculty of Medicine, Quebec, Canada.,McGill University Health Center, Montreal, Quebec, Canada
| | - Andre Dascal
- Jewish General Hospital, Quebec, Canada.,McGill University Faculty of Medicine, Quebec, Canada
| | - Yves Longtin
- Jewish General Hospital, Quebec, Canada.,McGill University Faculty of Medicine, Quebec, Canada
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Kong LY, Eyre D, Walker AS, Corbeil J, Wilcox M, Bourgault AM, Dascal A, Oughton M, Michaud S, Toye B, Frost E, Poirier L, Brassard P, Turgeon N, Gilca R, Loo V. Comparison of Pulsed-Field Gel Electrophoresis and Whole Genome Sequencing in Clostridium difficile Typing. Open Forum Infect Dis 2016. [DOI: 10.1093/ofid/ofw172.1611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Ling Yuan Kong
- McGill University Health Centre, Montreal, Quebec, Canada
| | - David Eyre
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - A. Sarah Walker
- NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | | | | | - Anne-Marie Bourgault
- McGill University Health Centre, Montreal, Quebec, Canada
- Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada
| | - Andre Dascal
- Jewish General Hospital, Montreal, Quebec, Canada
| | | | - Sophie Michaud
- Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Baldwin Toye
- Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada
| | - Eric Frost
- Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Quebec, Canada
| | | | - Paul Brassard
- McGill University Health Centre, Montreal, Quebec, Canada
| | - Nathalie Turgeon
- Centre Hospitalier Universitaire de Québec - Hôtel-Dieu de Québec, Quebec, Canada
| | - Rodica Gilca
- Quebec Institute of Public Health, Quebec, Quebec, Canada
| | - Vivian Loo
- McGill University Health Centre, Montreal, Quebec, Canada
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Brukner I, Longtin Y, Oughton M, Forgetta V, Dascal A. Assay for estimating total bacterial load: relative qPCR normalisation of bacterial load with associated clinical implications. Diagn Microbiol Infect Dis 2015; 83:1-6. [PMID: 26008123 DOI: 10.1016/j.diagmicrobio.2015.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/03/2015] [Accepted: 04/20/2015] [Indexed: 12/26/2022]
Abstract
Relative microorganism abundance is a parameter describing biodiversity, referring to how common a bacterial species is within the total bacterial flora. Anal, rectal, skin, mucal, and respiratory swabs are typical clinical samples where knowledge of relative bacterial abundance might make distinction between asymptomatic carriers and symptomatic cases. Assays trying to measure total bacterial load are usually based on the amplification of universal segments of 16S rRNA genes. Previous assays were not adoptable to "direct" PCR protocols, and/or they were not compatible with hydrolysis-based detection. Using the latest summary of universal 16S sequence motifs present in literature and testing our design with 500 liquid and 50 formed stool samples, we illustrate the performance characteristics of a new 16S quantitative PCR (qPCR) assay, which addresses well-known technical problems, including a) positive priming reaction in the absence of intended target due to self-priming and/or mispriming of unintended targets; b) amplification bias due to nonoptimal primer/probe coverage; and c) too large amplicons for clinical qPCR. Stool swabs ranked into bins of different bacterial loads show significant correlation with threshold cycle values of our new assay. To the best of our knowledge, this is the first description of qPCR assay measuring individual differences of total bacterial load present in human stool.
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Affiliation(s)
- Ivan Brukner
- Medical Faculty, McGill University, Montreal, Quebec, Canada; SMBD-Jewish General Hospital, Montreal, Quebec, Canada.
| | - Yves Longtin
- Medical Faculty, McGill University, Montreal, Quebec, Canada; SMBD-Jewish General Hospital, Montreal, Quebec, Canada
| | - Matthew Oughton
- Medical Faculty, McGill University, Montreal, Quebec, Canada; SMBD-Jewish General Hospital, Montreal, Quebec, Canada
| | | | - Andre Dascal
- Medical Faculty, McGill University, Montreal, Quebec, Canada; SMBD-Jewish General Hospital, Montreal, Quebec, Canada
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Kong LY, Dendukuri N, Schiller I, Bourgault AM, Brassard P, Poirier L, Lamothe F, Béliveau C, Michaud S, Turgeon N, Toye B, Frost EH, Gilca R, Dascal A, Loo VG. Predictors of asymptomatic Clostridium difficile colonization on hospital admission. Am J Infect Control 2015; 43:248-53. [PMID: 25728150 DOI: 10.1016/j.ajic.2014.11.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 11/21/2014] [Accepted: 11/24/2014] [Indexed: 02/04/2023]
Abstract
BACKGROUND Clostridium difficile (CD) is the leading cause of health care-associated diarrhea and can result in asymptomatic carriage. Rates of asymptomatic CD colonization on hospital admission range from 1.4%-21%. The objective of this study was to evaluate host and bacterial factors associated with colonization on admission. METHODS The Consortium de recherche québécois sur le Clostridium difficile study provided data for analysis, including demographic information, known risk factors, and potential confounding factors, prospectively collected for 5,232 patients from 6 hospitals in Quebec and Ontario over 15 months from 2006-2007. Stool or rectal swabs were obtained for culture on admission. Pulsed-field gel electrophoresis was performed on the isolates. The presence of antibody against CD toxins A and B was measured. RESULTS There were 212 (4.05%) patients colonized with CD on admission, and 5,020 patients were not colonized with CD. Multivariate logistic regression analysis showed that hospitalization within the last 12 months, use of corticosteroids, prior CD infection, and presence of antibody against toxin B were associated with colonization on admission. Of patients colonized on admission, 79.4% had non-NAP1, non-NAP2 strains. CONCLUSION There are identifiable risk factors among asymptomatic CD carriers that could serve in their detection and provide a basis for targeted screening.
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Affiliation(s)
- Ling Yuan Kong
- McGill University Health Centre, McGill University, Montréal, QC, Canada
| | - Nandini Dendukuri
- McGill University Health Centre, McGill University, Montréal, QC, Canada
| | - Ian Schiller
- McGill University Health Centre, McGill University, Montréal, QC, Canada
| | - Anne-Marie Bourgault
- McGill University Health Centre, McGill University, Montréal, QC, Canada; Centre Hospitalier Universitaire de Montréal, Université de Montréal, Montréal, QC, Canada
| | - Paul Brassard
- McGill University Health Centre, McGill University, Montréal, QC, Canada
| | - Louise Poirier
- Centre Hospitalier Universitaire de Montréal, Université de Montréal, Montréal, QC, Canada
| | - François Lamothe
- Hôpital Maisonneuve-Rosemont, Université de Montréal, Montréal, QC, Canada
| | - Claire Béliveau
- Centre Hospitalier Universitaire de Montréal, Université de Montréal, Montréal, QC, Canada
| | - Sophie Michaud
- Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Nathalie Turgeon
- Centre Hospitalier Universitaire de Québec-Hôtel-Dieu de Québec, Université Laval, Québec, QC, Canada
| | - Baldwin Toye
- Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada
| | - Eric H Frost
- Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Rodica Gilca
- Université Laval, Québec, QC, Canada; Institut national de santé publique du Québec, Québec, QC, Canada
| | - Andre Dascal
- Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - Vivian G Loo
- McGill University Health Centre, McGill University, Montréal, QC, Canada.
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Brukner I, Oughton M, Giannakakis A, Kerzner R, Dascal A. Significantly Improved Performance of a Multitarget Assay Over a Commercial SCCmec-Based Assay for Methicillin-Resistant Staphylococcus aureus Screening. J Mol Diagn 2013; 15:577-80. [DOI: 10.1016/j.jmoldx.2013.04.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 04/15/2013] [Accepted: 04/25/2013] [Indexed: 02/09/2023] Open
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Loo VG, Bourgault AM, Poirier L, Lamothe F, Michaud S, Turgeon N, Toye B, Beaudoin A, Frost EH, Gilca R, Brassard P, Dendukuri N, Béliveau C, Oughton M, Brukner I, Dascal A. Host and pathogen factors for Clostridium difficile infection and colonization. N Engl J Med 2011; 365:1693-703. [PMID: 22047560 DOI: 10.1056/nejmoa1012413] [Citation(s) in RCA: 582] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Clostridium difficile infection is the leading cause of health care-associated diarrhea, and the bacterium can also be carried asymptomatically. The objective of this study was to identify host and bacterial factors associated with health care-associated acquisition of C. difficile infection and colonization. METHODS We conducted a 15-month prospective study in six Canadian hospitals in Quebec and Ontario. Demographic information, known risk factors, potential confounding factors, and weekly stool samples or rectal swabs were collected. Pulsed-field gel electrophoresis (PFGE) was performed on C. difficile isolates to determine the genotype. Levels of serum antibodies against C. difficile toxins A and B were measured. RESULTS A total of 4143 patients were included in the study; 117 (2.8%) and 123 (3.0%) had health care-associated C. difficile infection and colonization, respectively. Older age and use of antibiotics and proton-pump inhibitors were significantly associated with health care-associated C. difficile infection. Hospitalization in the previous 2 months; use of chemotherapy, proton-pump inhibitors, and H(2) blockers; and antibodies against toxin B were associated with health care-associated C. difficile colonization. Among patients with health care-associated C. difficile infection and those with colonization, 62.7% and 36.1%, respectively, had the North American PFGE type 1 (NAP1) strain. CONCLUSIONS In this study, health care-associated C. difficile infection and colonization were differentially associated with defined host and pathogen variables. The NAP1 strain was predominant among patients with C. difficile infection, whereas asymptomatic patients were more likely to be colonized with other strains. (Funded by the Consortium de Recherche sur le Clostridium difficile.).
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Affiliation(s)
- Vivian G Loo
- Department of Microbiology, McGill University Health Centre, 687 Pine Ave. W., Rm. L5.06, Montreal, QC H3A 1A1, Canada
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Oughton M, Dascal A, Laporta D, Charest H, Afilalo M, Miller M. Evidence of viremia in 2 cases of severe pandemic influenza A H1N1/09. Diagn Microbiol Infect Dis 2011; 70:213-7. [PMID: 21397429 DOI: 10.1016/j.diagmicrobio.2010.12.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 12/06/2010] [Accepted: 12/16/2010] [Indexed: 12/01/2022]
Abstract
The recent pandemic of the 2009 pandemic influenza A (H1N1) infrequently caused severe disease. We describe 2 cases of 2009 H1N1 influenza with rapid progression resulting in respiratory failure and need for prolonged intensive care support. Real-time polymerase chain reaction amplification for influenza A (using a Centers for Disease Control and Prevention protocol) and the 2009 H1N1 influenza (using an in-house protocol) was performed on serial respiratory and serum specimens from both patients collected over 3 weeks. Both patients repeatedly demonstrated 2009 H1N1 influenza in respiratory specimens. Evidence of influenza A viremia was also detected in both cases, although it was confirmed as 2009 H1N1 influenza in only one. The presence of viremia in cases of severe 2009 H1N1 influenza has potential prognostic and therapeutic implications. Detection of viremia may be useful as a predictive marker for severe disease. Antiviral agents with low serum levels may be ineffective if administered to patients with influenza viremia.
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Affiliation(s)
- Matthew Oughton
- Division of Infectious Disease and Department of Microbiology, Jewish General Hospital, Montréal, Québec, Canada
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Dial S, Kezouh A, Dascal A, Barkun A, Suissa S. Patterns of antibiotic use and risk of hospital admission because of Clostridium difficile infection. CMAJ 2008. [PMID: 18838451 DOI: 10.1503/cmaj.071812179/8/767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Previous observations have indicated that infection with Clostridium difficile occurs almost exclusively after exposure to antibiotics, but more recent observations have suggested that prior antibiotic exposure may be less frequent among cases of community-acquired disease. METHODS We used 2 linked health databases to perform a matched, nested case-control study of elderly patients admitted to hospital with community-acquired C. difficile infection. For each of 836 cases among people 65 years of age or older, we selected 10 controls. We determined the proportion of cases that occurred without prior antibiotic exposure and estimated the risk related to exposure to different antibiotics and the duration of increased risk. RESULTS Of the 836 cases, 442 (52.9%) had no exposure to antibiotics in the 45-day period before the index date, and 382 (45.7%) had no exposure in the 90-day period before the index date. Antibiotic exposure was associated with a rate ratio (RR) of 10.6 (95% confidence interval [CI] 8.9-12.8). Clindamycin (RR 31.8, 95% CI 17.6-57.6), cephalosporins (RR 14.9, 95% CI 10.9-20.3) and gatifloxacin (RR 16.7, 95% CI 8.3-33.6) were associated with the highest risk. The RR for C. difficile infection associated with antibiotic exposure declined from 15.4 (95% CI 12.2-19.3) by about 20 days after exposure to 3.2 (95% CI 2.0-5.0) after 45 days. Use of a proton pump inhibitor was associated with increased risk (RR 1.6, 95% CI 1.3-2.0), as were concurrent diagnoses of inflammatory bowel disease (RR 4.1, 95% CI 2.6-6.6), irritable bowel syndrome (RR 3.4, 95% CI 2.3-5.0) and renal failure (RR 1.7, 95% CI 1.2-2.2). INTERPRETATION Community-acquired C. difficile infection occurred in a substantial proportion of individuals with no recent exposure to antibiotics. Among patients who had been exposed to antibiotics, the risk declined markedly by 45 days after discontinuation of use.
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Affiliation(s)
- Sandra Dial
- Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montréal, Que.
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10
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Dial S, Kezouh A, Dascal A, Barkun A, Suissa S. Patterns of antibiotic use and risk of hospital admission because of Clostridium difficile infection. CMAJ 2008; 179:767-72. [PMID: 18838451 PMCID: PMC2553880 DOI: 10.1503/cmaj.071812] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Previous observations have indicated that infection with Clostridium difficile occurs almost exclusively after exposure to antibiotics, but more recent observations have suggested that prior antibiotic exposure may be less frequent among cases of community-acquired disease. METHODS We used 2 linked health databases to perform a matched, nested case-control study of elderly patients admitted to hospital with community-acquired C. difficile infection. For each of 836 cases among people 65 years of age or older, we selected 10 controls. We determined the proportion of cases that occurred without prior antibiotic exposure and estimated the risk related to exposure to different antibiotics and the duration of increased risk. RESULTS Of the 836 cases, 442 (52.9%) had no exposure to antibiotics in the 45-day period before the index date, and 382 (45.7%) had no exposure in the 90-day period before the index date. Antibiotic exposure was associated with a rate ratio (RR) of 10.6 (95% confidence interval [CI] 8.9-12.8). Clindamycin (RR 31.8, 95% CI 17.6-57.6), cephalosporins (RR 14.9, 95% CI 10.9-20.3) and gatifloxacin (RR 16.7, 95% CI 8.3-33.6) were associated with the highest risk. The RR for C. difficile infection associated with antibiotic exposure declined from 15.4 (95% CI 12.2-19.3) by about 20 days after exposure to 3.2 (95% CI 2.0-5.0) after 45 days. Use of a proton pump inhibitor was associated with increased risk (RR 1.6, 95% CI 1.3-2.0), as were concurrent diagnoses of inflammatory bowel disease (RR 4.1, 95% CI 2.6-6.6), irritable bowel syndrome (RR 3.4, 95% CI 2.3-5.0) and renal failure (RR 1.7, 95% CI 1.2-2.2). INTERPRETATION Community-acquired C. difficile infection occurred in a substantial proportion of individuals with no recent exposure to antibiotics. Among patients who had been exposed to antibiotics, the risk declined markedly by 45 days after discontinuation of use.
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Affiliation(s)
- Sandra Dial
- Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montréal, Que.
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Schneider-Lindner V, Delaney JA, Dial S, Dascal A, Suissa S. Antimicrobial drugs and community-acquired methicillin-resistant Staphylococcus aureus, United Kingdom. Emerg Infect Dis 2008; 13:994-1000. [PMID: 18214170 PMCID: PMC2878234 DOI: 10.3201/eid1307.061561] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We report results of a case-control study of the association between receipt of antimicrobial agents and diagnosis of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) in the United Kingdom. Eligible adults, selected from the General Practice Research Database, had no previous diagnosis of MRSA, no hospitalization in the past 2 years, and > or = 2 years of follow-up recorded in the database. For 2000-2004, we identified 1,981 MRSA case-patients and 19,779 matched control-patients. The odds ratios (ORs) and 95% confidence intervals (CIs) of MRSA diagnosis for patients who were prescribed 1, 2-3, or > or = 4 antimicrobial drugs were 1.57 (CI 1.36-1.80), 2.46 (CI 2.15-2.83), and 6.24 (CI 5.43-7.17), respectively. Risk for community-acquired MRSA increased with number of antimicrobial drug prescriptions, appeared to vary according to antimicrobial drug classes prescribed the previous year, and was highest for quinolones (OR 3.37, CI 2.80-4.09) and macrolides (OR 2.50, CI 2.14-2.91).
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Nowak T, Patel AM, Dascal A, Haghighat F, Rastan S, Morofsky E, Butler I, Kozinski JA. Implementation of eWAR system in the neutralization of selected chemicals in building ventilation systems. ACTA ACUST UNITED AC 2007. [DOI: 10.2495/safe070531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Rudski LG, Dharsi K, Paterson DI, Dascal A, Eisenberg MJ. Patterns of treatment for native valve streptococus viridans endocarditis among cardiologists versus infectious disease specialists. J Am Coll Cardiol 2002. [DOI: 10.1016/s0735-1097(02)82040-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Zaharatos GJ, Dascal A, Miller MA. Discordant carbapenem susceptibility in Methylobacterium species and its application as a method for phenotypic identification. J Clin Microbiol 2001; 39:2037-8. [PMID: 11388170 PMCID: PMC88082 DOI: 10.1128/jcm.39.5.2037-2038.2001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Brenner B, Wainberg MA, Salomon H, Rouleau D, Dascal A, Spira B, Sekaly RP, Conway B, Routy JP. Resistance to antiretroviral drugs in patients with primary HIV-1 infection. Investigators of the Quebec Primary Infection Study. Int J Antimicrob Agents 2000; 16:429-34. [PMID: 11118853 DOI: 10.1016/s0924-8579(00)00270-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The widespread use of antiretroviral agents (ARVs) and the growing occurrence of HIV strains resistant to these drugs have given rise to serious concerns regarding the transmission of resistant viruses to newly infected persons. Plasma viral RNA from 80 individuals newly infected between 1997 and 1999 was genotyped by automated sequencing to analyze the profile of viruses resistant to nucleoside and non-nucleoside reverse transcriptase inhibitors (NRTIs and NNRTIs) and to protease inhibitors (PIs). The prevalence of mutations that conferred primary resistance to PIs (L10I, D30Y, V82A, L90M) was 15% of the cohort. RT genotypic variants, associated with high-level resistance to ARVs, were observed in 21% of individuals, including NRTI, NNRTI and multidrug (MDR) resistance in 6, 5, and 10% of cases, respectively. The phenotypic susceptibility of viral isolates to ARVs was also assayed and showed transmission of high-level resistance to ZDV, 3TC, and PIs in those individuals with MDR. The transmission of drug-resistant HIV genotypic variants is a serious problem that merits further attention by public health officials, virologists, and clinicians.
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Affiliation(s)
- B Brenner
- McGill University AIDS Centre, Lady Davis Institute-Jewish General Hospital, 3755 Cote Site-Catherine Road, Montreal, Quebec, Canada H3T 1E2
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Miller MA, Dascal A, Portnoy J, Mendelson J. Development of mupirocin resistance among methicillin-resistant Staphylococcus aureus after widespread use of nasal mupirocin ointment. Infect Control Hosp Epidemiol 1996; 17:811-3. [PMID: 8985769 DOI: 10.1086/647242] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
All methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from colonized or infected patients in a 625-bed public teaching hospital during an epidemic, and for 3 years thereafter, underwent susceptibility testing to mupirocin. Mupirocin resistance among MRSA increased markedly over this period (1990, 2.7%; 1991, 8.0%; 1992, 61.5%; 1993, 65%) in association with increased use of mupirocin ointment as an adjunct to infection control measures.
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Affiliation(s)
- M A Miller
- Department of Microbiology, SMBD-Jewish General Hospital, Montreal, Quebec, Canada
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Miller MA, Dascal A, Portnoy J, Mendelson J. Development of Mupirocin Resistance among Methicillin-Resistant Staphylococcus aureus after Widespread Use of Nasal Mupirocin Ointment. Infect Control Hosp Epidemiol 1996. [DOI: 10.2307/30141176] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Miller MA, Thibert L, Desjardins F, Siddiqi SH, Dascal A. Growth inhibition of Mycobacterium tuberculosis by polyoxyethylene stearate present in the BACTEC pyrazinamide susceptibility test. J Clin Microbiol 1996; 34:84-6. [PMID: 8748279 PMCID: PMC228736 DOI: 10.1128/jcm.34.1.84-86.1996] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We have previously found that approximately 3.5% of 428 clinical isolates of Mycobacterium tuberculosis yield uninterpretable results in the BACTEC pyrazinamide (PZA) susceptibility test system, because of inadequate growth. We tested the hypothesis that polyoxyethylene stearate (POES), the ingredient of the reconstituting fluid for the test, was the cause of this growth inhibition. A total of 15 isolates known for their previously uninterpretable results and 100 randomly chosen clinical isolates were tested in parallel both with and without POES. Repeat testing of the isolates with previously uninterpretable results yielded results in the presence of POES in only seven (47%). In the absence of POES, all gave interpretable results but one such result showed false resistance. For the other 100 clinical isolates, interpretable results were obtained with and without POES, but growth was enhanced in the absence of POES, especially in the PZA-susceptible strains. This was evidenced by a decreased time to attain a growth index of 200 in the control vial (4.9 days without POES versus 5.8 days with POES; P < 0.001) and a higher mean growth index ratio on the day of interpretation of the test (7.4% without POES versus 2.2% with POES; P < 0.001). However, the enhanced growth without POES led to 20 susceptible strains being misinterpreted as either resistant or borderline. We suggest that isolates of M. tuberculosis which yield uninterpretable results in the BACTEC PZA test system should be retested both with and without POES. If interpretable results indicating PZA resistance are obtained only in the absence of POES, the result should be confirmed by a pyrazinamidase assay or by the conventional proportion method. Routine omission of POES from the BACTEC test for all clinical strains is discouraged because of the unacceptably high false-resistance rates.
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Affiliation(s)
- M A Miller
- McGill University, SMBD-Jewish General Hospital, Montreal, Quebec, Canada
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19
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Miller MA, Thibert L, Desjardins F, Siddiqi SH, Dascal A. Testing of susceptibility of Mycobacterium tuberculosis to pyrazinamide: comparison of Bactec method with pyrazinamidase assay. J Clin Microbiol 1995; 33:2468-70. [PMID: 7494049 PMCID: PMC228441 DOI: 10.1128/jcm.33.9.2468-2470.1995] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The susceptibility of 428 clinical isolates of Mycobacterium tuberculosis to pyrazinamide was assessed by the Bactec method and the Wayne pyrazinamidase assay. The correlation between the two tests was 98.2 and 100% for susceptible and resistant strains, respectively. False resistance was seen in four (0.8%) strains with the Bactec test, and false-susceptible results occurred in two (0.5%) pyrazinamidase assays. The Bactec test is rapid and reliable, and the Bactec results correlate well with the pyrazinamidase test results, although some strains did not grow well in the test medium.
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Affiliation(s)
- M A Miller
- McGill University, Montreal, Quebec, Canada
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20
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Abstract
The serogroup/serotypes (SGTs) and antimicrobial susceptibilities to 10 antimicrobial agents of 110 clinical strains of Streptococcus pneumoniae were determined. Strains intermediately resistant or highly resistant to penicillin G (80 of 110) belonged predominantly to SGTs 23 (45.0%), 19 (13.7%), 6 (10.0%), 9 (6.2%), and 14 (3.7%). The MICs of all cephalosporins, tetracycline, trimethoprim-sulfamethoxazole, and chloramphenicol increased along with the MICs of penicillin G. However, erythromycin resistance and clindamycin resistance were observed more frequently among the intermediately penicillin-resistant strains. Multiple resistance was observed for 32 strains, of which 25 were highly resistant to penicillin G and belong to SGT 23F. All strains were susceptible to vancomycin.
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Affiliation(s)
- L P Jetté
- Laboratoire de santé publique du Québec, Sainte-Anne-de-Bellevue, Canada
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21
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Dascal A, Libman M. Reply. Clin Infect Dis 1992. [DOI: 10.1093/clinids/15.1.170-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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23
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Tessler M, Dascal A, Gioseffini S, Miller M, Mendelson J. Growth curves of Staphylococcus aureus, Candida albicans, and Moraxella osloensis in propofol and other media. Can J Anaesth 1992; 39:509-11. [PMID: 1534525 DOI: 10.1007/bf03008718] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Propofol, 2,6 diisopropylphenol, in an emulsion formulation (Diprivan), has been associated with postsurgical infections caused by Staphylococcus aureus, Moraxella osloensis and Candida albicans. These organisms were individually inoculated into each of the following media: (1) the emulsion preparation of propofol, (2) Intralipid 10%, (3) pure 2,6 diisopropylphenol, and (4) trypticase soy broth (TSB). The organisms were incubated and subcultured hourly for eight hours at room temperature. Propofol supported the growth of all three organisms, but for S. aureus and M. osloenis, the growth rate was slower in propofol than in TSB (P less than 0.05). There was no difference between the growth rate of any organism in propofol than in Intralipid 10%. The authors conclude that propofol, in the emulsion formulation, supports bacterial growth and, therefore, must be prepared for administration in an aseptic manner. Also, by administering propofol soon after preparation, the risk of introduction of a significant inoculum to the patient will be reduced.
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Affiliation(s)
- M Tessler
- Department of Anaesthesia and Medicine, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada
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24
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Yechouron A, Dascal A, Stevenson J, Mendelson J. Ability of National Committee for Clinical Laboratory Standards-recommended quality control strains from the American Type Culture Collection to detect errors in disk diffusion susceptibility tests. J Clin Microbiol 1991; 29:2758-62. [PMID: 1757546 PMCID: PMC270428 DOI: 10.1128/jcm.29.12.2758-2762.1991] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The National Committee for Clinical Laboratory Standards (NCCLS) recommends, as a quality control for the disk diffusion susceptibility test, the use of three strains from the American Type Culture Collection: Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, and Escherichia coli ATCC 25922. This study assesses the capacity of these strains to detect errors in the overall method. ATCC strains were tested by comparing testing by the standard NCCLS-recommended procedure (ST) with testing under the following conditions: incubation at 25 degrees C, Mueller-Hinton agar depths of 2 mm (AD2) and 8 mm (AD8), agar pHs of 6.5 and 8, inocula with McFarland standards of 0.25 (0.25M) and 4.0 McFarland (4.0M), direct inoculation without preincubation of inoculum (DI), and a 2-h delay between inoculation and disk application (2HR). The frequency of zone measurements outside the NCCLS-recommended control zone limits were as follows: ST, 0%; AD2, 18%; AD8, 9.6%; pH 6.5, 7.9%; pH 8, 5.3%; 0.25M, 3.5%; 4.0M, 24%; DI, 3.4%; 2HR, 1.8%; 25 degrees C (only E. coli and P. aeruginosa were evaluable), 28%. These results suggest that the quality control strains are only partially effective in detecting single extreme laboratory errors and that careful laboratory supervision is necessary even in the setting of properly monitored quality control strains.
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Affiliation(s)
- A Yechouron
- Department of Microbiology and Infectious Diseases, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada
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25
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Libman MD, Dascal A, Kramer MS, Mendelson J. Strategies for the prevention of neonatal infection with herpes simplex virus: a decision analysis. Rev Infect Dis 1991; 13:1093-104. [PMID: 1663650 DOI: 10.1093/clinids/13.6.1093] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Decision analysis was used in the evaluation of nine strategies for the prevention of neonatal infection with herpes simplex virus (HSV). These strategies involve physical examination at labor, weekly screening of pregnant women for shedding of HSV, use of serologic methods specific for HSV type 2, and performance of a rapid diagnostic test at labor. Rates of cesarean delivery and of neonatal infection with HSV were estimated for each strategy, and the estimates were compared with those for a strategy of no intervention. The effects of variations in the sensitivities and specificities of the diagnostic and serologic tests used were analyzed. Given the currently available data and technology, physical examination at labor is the optimal strategy if the primary goal is to minimize the ratio of excess cesarean sections to cases of neonatal HSV infection averted.
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Affiliation(s)
- M D Libman
- Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada
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26
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Delage G, Turgeon F, Dascal A, Mendelson J, Lescop J. Infectious diseases as a subspecialty in Canada: status of the practice in Quebec. Rev Infect Dis 1991; 13:761-2. [PMID: 1925295 DOI: 10.1093/clinids/13.4.761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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27
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Bartter T, Irwin RS, Abraham JL, Dascal A, Nash G, Himmelstein JS, Jederlinic PJ. Zirconium compound-induced pulmonary fibrosis. Arch Intern Med 1991; 151:1197-201. [PMID: 2043021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Despite suspicion that inhalation of zirconium should be capable of causing human pulmonary disease, documentation of zirconium pneumoconiosis in humans has been lacking. We studied a likely case of zirconium compound-induced pulmonary fibrosis. The diagnosis was based on the following: (1) a history of gradual increase in symptoms and slowly progressing pulmonary fibrosis by chest roentgenogram compatible with a pneumoconiosis; (2) an appropriate history of exposure and a latency period of about 15 years before the onset of dyspnea and of roentgenographic changes; (3) analysis of open lung biopsy material revealing end-stage fibrosis and honeycombing, a moderate number of birefringent particles, and extremely high levels of a variety of zirconium compounds; and (4) no other potential cause of fibrosis. We conclude that zirconium should be considered a likely cause of pneumoconiosis and that appropriate precautions should be taken in the workplace.
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Affiliation(s)
- T Bartter
- Division of Pulmonary and Critical Care Medicine, Cooper Hospital, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Camden
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28
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Bartter T, Dascal A. The "toxic strep syndrome": severe group A streptococcal disease in the absence of bacteremia. Rev Infect Dis 1990; 12:1204-5. [PMID: 2267492 DOI: 10.1093/clinids/12.6.1204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Affiliation(s)
- A Dascal
- Sir Mortimer B. Davis--Jewish General Hospital, Montreal, Quebec, Canada
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Gomez-Rodrigo J, Mendelson J, Black M, Dascal A. Streptococcus pneumoniae acute suppurative parotitis in a patient with Sjögren's syndrome. J Otolaryngol 1990; 19:195-6. [PMID: 2192076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A case of suppurative parotitis due to Streptococcus pneumoniae is reported in a patient with Sjögren's syndrome. The rarity of this condition is noted by a review of the literature.
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Affiliation(s)
- J Gomez-Rodrigo
- Department of Microbiology and Infectious Diseases, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, Canada
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31
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Dascal A, Chan-Thim J, Morahan M, Portnoy J, Mendelson J. Replacement of special enzyme immunoassay transport medium by a standard viral transport medium in the Herpcheck herpes simplex virus antigen detection test. Diagn Microbiol Infect Dis 1989; 12:473-5. [PMID: 2560418 DOI: 10.1016/0732-8893(89)90080-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A new direct herpes simplex virus antigen enzyme immunoassay (EIA) uses a special EIA transport medium (ETM) for transport of herpes simplex virus (HSV) specimens. As ETM lyses the virus precluding culture and typing, we evaluated the relative performance of this EIA when performed on specimens transported in either ETM or a standard viral transport medium (VTM). These EIA results were also compared to cell culture performed on specimens transported in VTM (VTM-CC) and direct rapid inoculation into cell culture (CC). Based on all confirmed positives, by any test, the sensitivities for CC was 97% (66/68), for VTM-CC 91% (62/68), for ETM-EIA 97% (66/68), and for VTM-EIA 93% (63/68). It appears that VTM may be a slightly less desirable substitute than ETM in the performance of EIA. However, VTM-EIA is certainly as sensitive as cell culture performed on VTM.
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Affiliation(s)
- A Dascal
- Department of Medical Microbiology and Infectious Diseases, SMBD-Jewish General Hospital, Montreal, Quebec, Canada
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Brenner BG, Dascal A, Margolese RG, Wainberg MA. Natural killer cell function in patients with acquired immunodeficiency syndrome and related diseases. J Leukoc Biol 1989; 46:75-83. [PMID: 2659714 DOI: 10.1002/jlb.46.1.75] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
This review describes current knowledge of changes in natural killer (NK) cell function in acquired immunodeficiency syndrome (AIDS)-related disorders, vis-à-vis associated abnormalities in NK cytolytic function, NK cell subset distribution, NK cytopathology, and lymphokine regulation. NK cells, which are closely associated with large granular lymphocytes, are spontaneously cytotoxic to tumor and virally infected targets. As such, they may play a role in natural resistance to human immunodeficiency virus type 1 (HIV-1)-associated disorders and other opportunistic infections. Yet, peripheral blood NK activity is frequently reduced in patients with HIV-1-induced disease. NK cells are heterogeneous both with respect to their expression of serologically defined membrane antigens and functional activity. In AIDS-related syndromes, there appears to be a diminution of the NK pool (CD16+ cells) involved in cytolytic function, while there is an elevation of the NK pool that coexpresses NK (Leu 7+) and T (CD8+) cell markers, which show little or no involvement in cytolytic function. The impairment of in vitro NK function is not associated with a reduced frequency of lytic conjugates of effectors and target cells nor with the recycling capacity of these effector cells but rather is associated with defects in the NK cell lytic machinery following formation of such conjugates. NK cells in AIDS patients show an impairment in effector cell microtubule rearrangement following target cell interaction. The causes of NK cell dysfunction in AIDS-related disorders remain unknown. NK cells do not appear to express the CD4 epitope of the HIV receptor, nor have they been demonstrated to be susceptible to infection by HIV-1. There appears to be a preponderance of immature NK cells and a lymphokine imbalance in patients with HIV-1 associated disease. Interleukin-2 can partially restore diminished in vitro NK function. Elucidation of the involvement of the NK compartment in natural resistance to HIV-1 merits further investigation.
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Affiliation(s)
- B G Brenner
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec, Canada
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Dascal A, Chan-Thim J, Morahan M, Portnoy J, Mendelson J. Diagnosis of herpes simplex virus infection in a clinical setting by a direct antigen detection enzyme immunoassay kit. J Clin Microbiol 1989; 27:700-4. [PMID: 2542362 PMCID: PMC267400 DOI: 10.1128/jcm.27.4.700-704.1989] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A commercial 4-h direct herpes simplex virus (HSV) antigen detection enzyme immunoassay (EIA) kit (Du Pont Herpchek) was evaluated by using 273 clinical specimens obtained in a hospital-based infectious disease practice. The EIA was compared with a standard culture method in which WI38 cells were inoculated within 20 min of sample collection. Cultures were observed for 2 weeks, and positive findings were confirmed by fluorescein-labeled monoclonal antibody (FA) staining. The values for the overall HSV detection rate were 40.7% by the standard culture method and 41.4% by EIA. In eight cases, the EIA was positive, while the culture method was negative; however, clinical data and confirmatory blocking EIA suggested that a true HSV infection was present. For six FA-confirmed, culture-positive samples, the direct EIA was negative; however, an EIA performed on the supernatants of these cultures was positive, suggesting that the failure of the EIA to detect these samples was not due to lack of strain specificity of the test. After confirmatory tests of standard culture and EIA discrepant results, the overall sensitivity of the test was 95.0% (113 of 119) and the specificity was 100% (154 of 154).
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Affiliation(s)
- A Dascal
- Department of Microbiology and Infectious Diseases, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada
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Wainberg MA, Dascal A, Blain N, Fitz-Gibbon L, Boulerice F, Numazaki K, Tremblay M. The effect of cyclosporine A on infection of susceptible cells by human immunodeficiency virus type 1. Blood 1988; 72:1904-10. [PMID: 2904290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The effect of cyclosporine A (CyA) on the ability of the human immunodeficiency virus type 1 (HIV-1) to infect the H-9 T-cell leukemic line, as well as interleukin-2 (IL-2)-grown human peripheral blood-derived lymphocytes, has been studied. Pretreatment of H-9 cells and human lymphocytes with CyA over 24 hours completely prevented viral infection over a 21-day period, whereas the addition of drug at two hours postinfection with HIV-1 had a significant inhibitory effect on viral replication and expression of the virus-specific antigens p17 and p24. However, if CyA was added at later times to these lymphocytic cells, this inhibitory effect was lost. Indeed, the removal of CyA from cultures that had been treated from two hours after infection led to the rapid production of progeny virus. HIV-1 was able to infect peripheral blood lymphocytes obtained from each of four kidney allograft recipients on long-term CyA antirejection therapy, as long as drug was not included in the culture medium. In addition, we asked what effect pretreatment with CyA of cells of the U-937 monocytic line and primary cultures of human monocytes/macrophages might have on infection by HIV-1. CyA had no demonstrable effect on the ability of HIV-1 to infect cells of either type.
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Affiliation(s)
- M A Wainberg
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis, Jewis General Hospital, Montreal, Quebec, Canada
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Abstract
Three patients presented with multisystem disease that shared many of the features of toxic shock syndrome. Bacteriologic and serologic evidence strongly suggested that group A beta-hemolytic Streptococcus had caused the illnesses. Group A streptococcal infection may be an underdiagnosed cause of a toxic streptococcal syndrome, a syndrome of multisystem disease apparently mediated by toxins.
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Affiliation(s)
- T Bartter
- Division of Pulmonary and Critical Care Medicine, University of Massachusetts Medical School, Worcester
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Abstract
The antimicrobial susceptibility profiles of a total of 318 aerobic and facultatively anaerobic bacteria (255 gram-negative bacilli and 63 gram-positive cocci) were determined, using a new commercially available breakpoint broth microdilution procedure (Sensititer Breakpoint System (SBS), Gibco Diagnostics, Inc., Madison, WI) that categorizes test results in the form of susceptibility categories: susceptible, intermediate, and resistant. Results obtained with the SBS were compared with those achieved with a standardized disk diffusion procedure. Among a total of 4,414 organism-antimicrobic comparisons, concordance between the results of the SBS and the disk diffusion procedure was observed in 3,888 cases (88.1%). Four hundred twenty-three (9.6%) minor discrepancies, 45 (1.0%) major discrepancies, and 58 (1.3%) very major discrepancies were noted. Arbitration of major and very major discrepancies with a full-range minimum inhibitory concentration (MIC) procedure confirmed the results of the SBS in 53.4% of cases. A single organism-antimicrobial combination, the nonenterococcal streptococci tested against the aminoglycosides, yielded a significant number of very major errors which were arbitrated in favor of the disk diffusion result. These errors were probably due to poor growth of the test organism in the broth medium used for performing the SBS test (i.e., cation-supplemented Mueller-Hinton broth). With this exception, the SBS was found to be at least as accurate as the standardized disk diffusion procedure.
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Dascal A, Gleckman R. Serial knee infections with enteric pathogens. Hosp Pract (Off Ed) 1984; 19:32I, 32L, 32P. [PMID: 6430931 DOI: 10.1080/21548331.1984.11702883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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