Journal of clinical microbiology
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J. Clin. Microbiol. · Oct 2004
Review Case ReportsMitral bioprosthetic valve endocarditis caused by an unusual microorganism, Gemella morbillorum, in an intravenous drug user.
We report a case of Gemella morbillorum mitral bioprosthetic valve endocarditis with perivalvular extension in a 44-year-old human immunodeficiency virus-positive man who is an active intravenous drug user together with review of all published cases. This is only the second reported case of Gemella morbillorum endocarditis in a patient with a prosthetic valve.
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J. Clin. Microbiol. · Oct 2004
Case ReportsTropheryma whipplei Infection of an acellular porcine heart valve bioprosthesis in a patient who did not have intestinal Whipple's disease.
Rare cases of culture-negative infective endocarditis are caused by Tropheryma whipplei, the uncommon bacterium of Whipple's disease. We evaluated an 80-year-old woman with valvular heart disease but without intestinal Whipple's disease. The diagnosis of aortic valve xenograft culture-negative infection with T. whipplei was established by multiple molecular assays and by electron microscopy. ⋯ The quantification of T. whipplei genome equivalents by real-time PCR indicated a high-density bacterial colonization of the valve tissue. Additionally, an ultrastructural examination revealed numerous rod-shaped bacteria consistent in size with T. whipplei in the extracellular collagen matrix of the bioprosthesis. We conclude that extracellular growth of T. whipplei can occur in the microenvironment of biological prosthetic valve tissue and that T. whipplei endocarditis can occur in the absence of intestinal Whipple's disease.
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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. · Oct 2004
Direct detection of rifampin-resistant mycobacterium tuberculosis in respiratory specimens by PCR-DNA sequencing.
This study evaluated the feasibility of a molecular strategy based on identification of Mycobacterium tuberculosis by IS6110 PCR or Cobas Amplicor PCR, and rpoB PCR-DNA sequencing of the 81-bp rifampin resistance determining region (RRDR) for direct detection of rifampin resistance in respiratory specimens. A collection of 2,138 respiratory specimens and 352 nonduplicate M. tuberculosis isolates (including 233 isolates from the evaluated respiratory specimens and an additional collection of 119 stored isolates) from Southern China was investigated. Using culture as the reference test, the overall diagnostic sensitivities of an acid-fast bacillus (AFB) smear, Cobas Amplicor PCR, IS6110 PCR were 54.5% (156 of 286), 86.7% (248 of 286), and 89.2% (255 of 286), respectively. ⋯ Thirty-nine mutations of nine distinct kinds, eight point mutations, and one deletion within the RRDR were found in the 39 resistant strains. For the direct DNA sequencing performed on rpoB PCR-positive respiratory specimens, the concordance with the agar proportion method and the subsequent PCR-sequencing for the culture isolate was 100%. This strategy has potential application for direct and rapid diagnosis of rifampin-resistant M. tuberculosis in IS6110 PCR or Cobas Amplicor PCR-positive respiratory specimens.
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J. Clin. Microbiol. · Oct 2004
Performance of the Binax NOW Streptococcus pneumoniae urinary antigen assay for diagnosis of pneumonia in children with underlying pulmonary diseases in the absence of acute pneumococcal infection.
The performance of the Binax NOW immunochromatographic test for detecting Streptococcus pneumoniae antigen in urine specimens from 103 children presenting underlying pulmonary diseases with no recent pneumococcal infection was assessed. Our data indicate that this assay is unlikely to be useful for discriminating between children with and without pneumococcal pneumonia.