Evaluation of biosite triage Clostridium difficile panel for rapid detection of Clostridium difficile in stool samples.

One hundred two stool samples were tested by both the rapid Triage Clostridium difficile Panel (Triage Panel) and the cytotoxin cell culture assay. Five samples positive by both the C. difficile toxin A (Tox A) and common antigen components of the Triage Panel had cytotoxin titers of > or =10,000. Twenty-three samples were Triage Panel Tox A negative but common antigen positive. Ten of these had cytotoxin titers of 10 to 1,000, but 13 were cytotoxin negative. Bacterial isolates obtained from 8 of these 13 specimens were analyzed for Tox A and B genes by PCR, and only two contained toxigenic bacteria. Thus, the majority of samples positive only for C. difficile common antigen contained nontoxigenic bacteria. A Triage Panel Tox A-positive result indicated a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 33.3, 100, 100, and 88.2%, respectively. A Triage Panel common antigen-positive result indicated a sensitivity, specificity, PPV, and NPV of 100, 82.7, 53.6, and 100%, respectively. The high NPV of the Triage Panel common antigen, together with rapid reporting of results, should prove useful in avoiding unnecessary use of contact precautions and antibiotic treatment for C. difficile-negative patients. However, with Triage Panel common antigen-positive patients, a sensitive cytotoxin assay should be used to distinguish true cytotoxin-positive patients from C. difficile carriers.

Use of plastic vacutainer tubes for quantification of human immunodeficiency virus type 1 in blood specimens.

Human immunodeficiency virus type 1 viral load results were compared for paired samples collected in plastic and glass Vacutainer tubes, using both standard (n = 60) and ultrasensitive (n = 66) assays. The results showed a strong correlation (P < 0.0001), and plastic tubes can be substituted for glass tubes.

A multisite trial comparing two cytomegalovirus (CMV) pp65 antigenemia test kits, biotest CMV brite and Bartels/Argene CMV antigenemia.

A total of 513 blood specimens, predominantly from organ transplant recipients, human immunodeficiency virus-positive patients, and bone marrow transplant recipients, were tested for cytomegalovirus (CMV) by culture and pp65 antigenemia across four test sites. Peripheral blood leukocytes were examined by using both the Biotest CMV Brite and the Bartels/Argene CMV Antigenemia kits. A total of 109 specimens were positive for CMV, 106 (97%) were positive by antigenemia, and 34 (31%) were positive by culture. According to the manufacturers' instructions, 150,000 cells were applied per slide for the Biotest kit and 200,000 cells per slide for the Bartels kit. A total of 93 specimens (88%) were positive by the Biotest kit, and 86 (81%) were positive by the Bartels kit. In specimens found to be positive by only one kit, the positive cell counts were low (median, 1; range, 1 to 7). When the data from all four sites were combined and analyzed, there was no statistical difference between the performance of the two kits; the Biotest and Bartels kits were found to be equivalent in sensitivity, specificity, and positive and negative predictive values for the detection of CMV pp65 antigenemia.

A standardized plaque reduction assay for determination of drug susceptibilities of cytomegalovirus clinical isolates.

Twelve laboratories collaborated in formulating and testing a standardized plaque reduction assay for cytomegalovirus (CMV) cell-associated clinical isolates. Four characterized and plaque-purified CMV strains, as well as six coded clinical isolates obtained after antiviral therapy, were distributed and tested. Good agreement was obtained for four of the clinical isolates, but a broad distribution of results was obtained for two isolates. Analysis of these results indicates the problems associated with clinical isolates, including the large genetic variability and the highly cell-associated phenotype. This collaborative effort, by addressing these problems, represents a significant step toward the development of a standardized assay.

SimulFluor respiratory screen for rapid detection of multiple respiratory viruses in clinical specimens by immunofluorescence staining.

A new rapid direct immunofluorescence assay (DFA) respiratory screen reagent for detection of seven common respiratory viruses (respiratory syncytial virus [RSV], influenza A and B viruses, parainfluenza virus types 1 to 3, and adenovirus) was compared with standard single or dual DFA reagents and culture. In total, 1,531 respiratory samples were adequate for testing with both SimulFluor Respiratory Screen (RS) reagent (Chemicon International, Temecula, Calif.) and single or dual DFA reagents. The RS DFA reagent detected 367 (98.4%) and single or dual DFA reagents detected 368 (98.7%) of 373 DFA-positive samples. In addition, the RS DFA reagent was equivalent to or better than culture for detection of all viruses except adenovirus. Only 15 of 799 (1.9%) RS-negative samples inoculated into cell cultures yielded respiratory virus isolates (one RSV, five influenza A virus, two influenza B virus, one parainfluenza virus, and six adenovirus). Sixty-six other virus isolates (13 rhinovirus, 24 cytomegalovirus, 28 herpes simplex virus type 1, and 1 enterovirus) were also recovered in culture. With cytospin preparation of slides, only 7.5% of samples submitted were deemed inadequate for DFA. The availability of a rapid DFA screening reagent for detection of multiple common respiratory viruses within 1 to 2 h of sample collection should be of great benefit in terms of patient management and infection control.

2-Hour cytomegalovirus pp65 antigenemia assay for rapid quantitation of cytomegalovirus in blood samples.

Of 109 blood samples tested for cytomegalovirus (CMV) antigenemia, 18 (16.5%) were positive. CMV Brite detected 13 and CMV Brite Turbo detected 16 of the 18 positives. There was no significant difference in the number of positive cells detected per sample. The seven discrepant samples contained a median of only one positive cell.

Impact of sample type on rapid detection of influenza virus A by cytospin-enhanced immunofluorescence and membrane enzyme-linked immunosorbent assay.

Cytospin-enhanced direct fluorescent-antibody assay (DFA) detected 49 (92.5%) and rapid membrane enzyme-linked immunosorbent assay (ELISA) detected 40 (75.5%) of 53 influenza virus A-positive samples. All 15 positive nasopharyngeal aspirates from children were detected by both tests. In contrast, 34 of 38 (89.5%) positive swabs from adults were detected by DFA, but only 25 (66%) were detected by ELISA.

Lack of reactivity to CMV pp65 antigenemia testing in a patient with CMV disease following allogeneic bone marrow transplant.

Pre-emptive antiviral therapy based on the early detection of CMV infection is an important strategy for the prevention of CMV disease following allogeneic BMT. Accepted methods for early detection of CMV infection include viral culture of blood or bronchial lavage specimens or CMV pp65 antigenemia testing of peripheral blood specimens. We describe a patient with aplastic anemia with worsening liver transaminases after allogeneic bone marrow transplantation who had repeated negative tests for CMV pp65 antigenemia despite positive viral blood cultures. Re-examination of peripheral blood samples with a different pp65 antibody pool revealed the presence of high levels of CMV in peripheral blood leukocytes, confirming a lack of reactivity to the original antibody pool. Following institution of antiviral therapy, a prompt reduction in the number of pp65 antigen-positive peripheral blood leukocytes paralleled a reduction in abnormal transaminases. The practical implications of these findings are discussed.

Papular-purpuric gloves and socks syndrome associated with acute parvovirus B19 infection: case report and review.

The papular-purpuric gloves and socks syndrome (PPGSS) was first described in 1990. This syndrome is characterized by fever, acral pruritus, edema, petechiae, and oral erosions. Subsequently, parvovirus B19 has been implicated, in most cases, as the causative agent of this syndrome. To date, with two exceptions, all published cases of PPGSS have been from Europe and the Middle East and have been mainly reported in the dermatology literature. Herein, we report what we believe to be only the second case of documented parvovirus B19-associated PPGSS occurring in the United States. The patient presented with the typical clinical syndrome, and the diagnosis of acute parvovirus B19 infection was documented by serial serologies that demonstrated development of IgM antibody to virus during the acute phase of infection and seroconversion to IgG antibody in the convalescent period. We then review the existing literature on this unusual syndrome and its association with parvovirus B19.

Use of a single swab in multi-microbe or flex trans transport medium for detection of Chlamydia trachomatis by Roche Amplicor PCR and culture in specimens from two different patient populations.

The Roche Amplicor PCR increased the detection of Chlamydia trachomatis compared with culture in promptly processed clinical specimens from a local clinic (100 and 86.5%, respectively) and in samples with delayed processing transported from distant facilities (100 and 72.7%, respectively). A single swab collected in culture transport medium was used. Two media, Multi-Microbe and Flex Trans, were tested and found to be equally acceptable.

Detection of herpes simplex virus in clinical specimens by cytospin-enhanced direct immunofluorescence.

For 275 samples tested for herpes simplex virus (HSV), cytospin-enhanced direct immunofluorescence using Chemicon HSV monoclonal antibodies identified 80 (95%) and culture identified 77 (92%) of 84 confirmed positive specimens. Cytospin-prepared slides contained a greater number of total cells than standard cell spots, resulting in fewer inadequate cell smears and a higher HSV detection rate.

Comparison of EDTA and acid-citrate-dextrose collection tubes for detection of cytomegalovirus antigenemia and infectivity in leukocytes before and after storage.

Duplicate blood samples collected in EDTA and acid-citrate-dextrose (ACD) were compared by cytomegalovirus (CMV) pp65 antigenemia and CMV infectivity on the day of sample collection and after 1 and 2 days of storage at 4 degrees C. No significant difference was detected between EDTA and ACD. However, CMV antigenemia was more sensitive than culture at all time points tested.

Use of a quantitative cytomegalovirus (CMV) antigenemia test in evaluating HIV+ patients with and without CMV disease.

Cytomegalovirus (CMV) infection remains a life-threatening infection in patients with HIV disease. A rapid, quantitative diagnostic technique is needed to adi in the diagnosis of CMV disease. This study was undertaken to evaluate the CMV antigenemia test in patients with HIV disease who are at risk for CMV disease. The study included 22 patients who underwent ophthalmologic exams or selected diagnostic techniques in whom CMV cultures and CMV antigenemia tests were performed. All of 11 patients with CMV disease had positive CMV antigenemia assays [range, 48-1,000 positive cells/2 x 10(5) peripheral blood leukocytes (PBL)], and 10 were also CMV viremic. There was no clinical evidence of CMV disease in 11 patients, including seven in whom the CMV antigenemia assay was negative and who remained without evidence of CMV disease after a median follow-up of 159 days. Four patients had low antigenemia levels. Of these four, two subsequently developed CMV retinitis. In conclusion, a positive CMV antigenemia result with > or = 48 positive cells/2 x 10(5) PBL correlated with concurrent CMV disease. The CMV antigenemia test appears to be a valuable tool for the rapid diagnosis of CMV disease in HIV-infected individuals.

Evaluation of CMV Brite kit for detection of cytomegalovirus pp65 antigenemia in peripheral blood leukocytes by immunofluorescence.

The CMV Brite antigenemia kit was compared with culture and an established cytomegalovirus pp65 antigenemia assay (CMV AG). Of 300 clinical specimens tested, 92 were positive by CMV Brite, 83 were positive by CMV AG, and 34 were positive by culture. Discrepancies could be attributed to anticytomegalovirus therapy or low-level antigenemia.

Rhinovirus stimulation of interleukin-6 in vivo and in vitro. Evidence for nuclear factor kappa B-dependent transcriptional activation.

To further understand the biology of rhinovirus (RV), we determined whether IL-6 was produced during RV infections and characterized the mechanism by which RV stimulates lung cell IL-6 production. In contrast to normals and minimally symptomatic volunteers, IL-6 was detected in the nasal washings from patients who developed colds after RV challenge. RV14 and RV1A, major and minor receptor group RVs, respectively, were potent stimulators of IL-6 protein production in vitro. These effects were associated with significant increases in IL-6 mRNA accumulation and gene transcription. RV was also a potent stimulator of IL-6 promoter-driven luciferase activity. This stimulation was modestly decreased by mutation of the nuclear factor (NF)-IL-6 site and abrogated by mutation of the NF-kappa B site in this promoter. An NF-kappa B-DNA binding activity, mediated by p65, p50, and p52 NF-kappa B moieties, was rapidly induced in RV-infected cells. Activator protein 1-DNA binding was not similarly altered. These studies demonstrate that IL-6 is produced during symptomatic RV infections, that RVs are potent stimulators of IL-6 elaboration, and that RV stimulation IL-6 production is mediated by an NF-kappa B-dependent transcriptional stimulation pathway. IL-6 may play an important role in the pathogenesis of RV infection, and NF-kappa B activation is likely to be an important event in RV-induced pathologies.