Journal of clinical microbiology
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We have recently described the discovery of a novel coronavirus, coronavirus HKU1 (CoV-HKU1), associated with community-acquired pneumonia. However, the clinical spectrum of disease and the epidemiology of CoV-HKU1 infections in relation to infections with other respiratory viruses are unknown. In this 12-month prospective study, 4,181 nasopharyngeal aspirates from patients with acute respiratory tract infections were subjected to reverse transcription-PCRs specific for CoV-HKU1 and human coronaviruses NL63 (HCoV-NL63), OC43 (HCoV-OC43), and 229E (HCoV-229E). ⋯ Two genotypes of CoV-HKU1 cocirculated during the study period. Continuous studies over a longer period are warranted to ascertain the seasonal variation and relative importance of the different coronaviruses. Similar studies in other countries are required to better determine the epidemiology and genetic diversity of CoV-HKU1.
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J. Clin. Microbiol. · Jun 2006
Detection of rtN236T and rtA181V/T mutations associated with resistance to adefovir dipivoxil in samples from patients with chronic hepatitis B virus infection by the INNO-LiPA HBV DR line probe assay (version 2).
The nucleotide analog adefovir dipivoxil (ADV) is an effective antiviral treatment for chronic hepatitis B virus (HBV) infection, with resistance to ADV estimated to occur less frequently than resistance to lamivudine treatment. The detection of ADV resistance mutations is necessary during therapy to monitor and anticipate possible treatment failure. The INNO-LiPA HBV DR v2 (LiPA; Innogenetics, Ghent, Belgium) is a DNA hybridization line probe assay for the detection of HBV polymerase mutations associated with resistance to lamivudine and ADV. ⋯ LiPA detected the rtN236T mutation at least 6 months earlier than its detection by sequencing in patients for whom consecutive serum samples were available. Although less sensitive, sequencing has the advantage of providing information on other polymerase mutations not represented on LiPA strips. The INNO-LiPA HBV DR v2 assay is a very sensitive and specific assay for the detection of the rtN236T mutation associated with resistance to ADV.
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J. Clin. Microbiol. · Jun 2006
Comparative StudyAn in-house RD1-based enzyme-linked immunospot-gamma interferon assay instead of the tuberculin skin test for diagnosis of latent Mycobacterium tuberculosis infection.
Identification of individuals infected with Mycobacterium tuberculosis is essential for the control of tuberculosis (TB). The specificity of the currently used tuberculin skin test (TST) is poor because of the broad antigenic cross-reactivity of purified protein derivative (PPD) with BCG vaccine strains and environmental mycobacteria. Both ESAT-6 and CFP-10, two secretory proteins that are highly specific for M. tuberculosis complex, elicit strong T-cell responses in subjects with TB. ⋯ Furthermore, respectively 76 and 59% of the ELISPOT-negative contacts responded in vitro to BCG and PPD, suggesting that most of them were BCG vaccinated or infected with nontuberculous mycobacteria. The number of spot-forming cells significantly correlated with TST induration (P < 0.0001). Our in-house ELISPOT assay based on a restricted pool of highly selected peptides is more accurate than TST for identifying individuals with latent TB infection and could improve chemoprophylaxis for the control of TB.
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J. Clin. Microbiol. · Jun 2006
Identification of a Haarlem genotype-specific single nucleotide polymorphism in the mgtC virulence gene of Mycobacterium tuberculosis.
MgtC is a virulence factor common to several intracellular pathogens, including Mycobacterium tuberculosis, that might have been acquired through horizontal gene transfer. In the present study, we investigated the polymorphism of mgtC in clinical isolates representative of the main epidemic groups of M. tuberculosis. MgtC appears to have a low polymorphism rate in M. tuberculosis that consists exclusively of nonsynonymous mutations. ⋯ The amino acid change (H182R) associated with the mgtC182 SNP in Haarlem strains does not appear to procure a selective advantage. Our results offer a simple and rapid tool to distinguish between Haarlem and non-Haarlem strains. In addition, the on/off switch assay, which allows the detection of SNPs on chromosomal DNA and M. tuberculosis cultures, provides a novel approach for the screening of known SNPs in M. tuberculosis.
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J. Clin. Microbiol. · May 2006
Comparative StudyComparison of DNA fingerprinting methods for use in investigation of type E botulism outbreaks in the Canadian Arctic.
Pulsed-field gel electrophoresis (PFGE), randomly amplified polymorphic DNA (RAPD) analysis, and automated ribotyping were compared for epidemiological typing of Clostridium botulinum type E using clinical and food isolates associated with four botulism outbreaks occurring in the Canadian Arctic. All type E strains previously untypeable by PFGE, even with the use of a formaldehyde fixation step, could be typed by the addition of 50 microM thiourea to the electrophoresis running buffer. ⋯ RAPD analysis of C. botulinum group II strains was not consistently reproducible with primer OPJ-6 or OPJ-13, apparently discriminating between epidemiologically related strains. A modified PFGE protocol was judged to be the most useful method for typing epidemiologically related C. botulinum type E strains, based on its ability to type all strains reproducibly and with an adequate level of discrimination.