Journal of clinical microbiology
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J. Clin. Microbiol. · Oct 2004
Detection of galactomannan antigenemia in patients receiving piperacillin-tazobactam and correlations between in vitro, in vivo, and clinical properties of the drug-antigen interaction.
Recent case reports describe patients receiving piperacillin-tazobactam who were found to have circulating galactomannan detected by the double sandwich enzyme-linked immunosorbent assay (ELISA) system, leading to the false presumption of invasive aspergillosis. Since this property of piperacillin-tazobactam and galactomannan ELISA is not well understood, we investigated the in vitro, in vivo, and clinical properties of this interaction. Among the 12 reconstituted antibiotics representing four classes of antibacterial compounds that are commonly used in immunocompromised patients, piperacillin-tazobactam expressed a distinctively high level of galactomannan antigen in vitro (P = 0.001). ⋯ Patients (n = 13) receiving piperacillin-tazobactam had significantly greater mean serum GMI values (0.74 +/- 0.14) compared to patients (n = 13) receiving other antibiotics (0.14 +/- 0.08) and compared to healthy blood bank donors (0.14 +/- 0.06) (P < 0.001). Five (38.5%) of thirteen patients receiving piperacillin-tazobactam had serum GMI values > 0.5 compared to none of thirteen subjects receiving other antibiotics (P = 0.039) and to none of ten healthy blood bank donors (P = 0.046). These data demonstrate that among antibiotics that are commonly used in immunocompromised patients, only piperacillin-tazobactam contains significant amounts of galactomannan antigen in vitro, that in animals receiving piperacillin-tazobactam circulating galactomannan antigen accumulates in vivo to significantly increased and sustained levels, and that some but not all patients receiving this antibiotic will demonstrate circulating galactomannan above the threshold considered positive for invasive aspergillosis by the recently licensed double sandwich ELISA.
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J. Clin. Microbiol. · Jul 2004
Detection of severe acute respiratory syndrome (SARS) coronavirus nucleocapsid protein in sars patients by enzyme-linked immunosorbent assay.
We report the development of an enzyme-linked immunosorbent assay (ELISA) for the detection of severe acute respiratory syndrome (SARS) coronavirus (CoV) nucleocapsid protein. The assay was carried out with hyperimmune polyclonal nucleocapsid-specific antibodies from guinea pigs and rabbits immunized with recombinant His(6)-tagged SARS CoV nucleocapsid protein. The assay was used for the detection of SARS CoV nucleocapsid protein in nasopharyngeal aspirate, urine, and fecal samples collected from patients with confirmed SARS between days 2 and 33 after the onset of illness. ⋯ Moreover, the protein could be detected in 25 (83%) of 30 nasopharyngeal aspirate specimens obtained from days 11 to 15 and in all 7 fecal specimens obtained from days 21 to 32. Since the present ELISA is more convenient and economical than reverse transcription-PCR, it may serve as an alternative tool for the early diagnosis of SARS CoV infection in laboratories with limited resources and expertise and for mass screening for the reservoir of SARS CoV. Further studies on serial clinical specimens should reveal the duration of nucleocapsid protein shedding and may reveal a higher detection rate in SARS patients.
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J. Clin. Microbiol. · Jul 2004
Identification of the severe acute respiratory syndrome coronavirus by simultaneous multigene DNA sequencing.
The recent severe acute respiratory syndrome (SARS) outbreak resulted in calls for an accurate diagnostic test that can be used not only for routine testing but also for generating nucleotide sequences to monitor the epidemic. Although the identity of the SARS coronavirus (SARS-CoV) genome was confirmed by DNA sequencing, it is impractical to sequence the entire 29-kb SARS-CoV genome on a routine basis. ⋯ Instead of requiring the sequencing of the whole SARS-CoV genome, our modification enables the simultaneous sequencing of three regions of the SARS-CoV genome, the spike protein-encoding gene (35 nucleotides), gene M (43 nucleotides), and gene N (45 nucleotides), in a single electropherogram. Comparing these nucleotide sequences to DNA databank entries (National Institutes of Health) conclusively identified them as SARS-CoV sequences.
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J. Clin. Microbiol. · May 2004
Comparative StudyComparison of chlorhexidine and tincture of iodine for skin antisepsis in preparation for blood sample collection.
Rates of contamination of blood cultures obtained when skin was prepared with iodine tincture versus chlorhexidine were compared. For iodine tincture, the contamination rate was 2.7%; for chlorhexidine, it was 3.1%. The 0.41% difference is not statistically significant. Chlorhexidine has comparable effectiveness and is safer, cheaper, and preferred by staff, so it is an alternative to iodine tincture.
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J. Clin. Microbiol. · Apr 2004
Rapid and sensitive method using multiplex real-time PCR for diagnosis of infections by influenza a and influenza B viruses, respiratory syncytial virus, and parainfluenza viruses 1, 2, 3, and 4.
Laboratory diagnosis of viral respiratory infections is generally performed by virus isolation in cell culture and immunofluorescent assays. Reverse transcriptase PCR is now recognized as a sensitive and specific alternative for detection of respiratory RNA viruses. A rapid real-time multiplex PCR assay was developed for the detection of influenza A and influenza B viruses, human respiratory syncytial virus (RSV), parainfluenza virus 1 (PIV1), PIV2, PIV3, and PIV4 in a two-tube multiplex reaction which used molecular beacons to discriminate the pathogens. ⋯ The application of real-time PCR to clinical samples increases the sensitivity for respiratory viral diagnosis. In addition, results can be obtained within 6 h, which increases clinical relevance. Therefore, use of this real-time PCR assay would improve patient management and infection control.