Yi-Wei Tang

Herpesvirus DNA Is Consistently Detected in Lungs of Patients with Idiopathic Pulmonary Fibrosis

ABSTRACT On the basis of earlier reports associating Epstein-Barr Virus (EBV) with half of the cases of idiopathic pulmonary fibrosis (IPF), we hypothesized that chronic infection with EBV or a closely related herpesvirus would be detected in all cases of IPF. We tested lung specimens from 33 IPF patients (8 patients with familial IPF and 25 patients with sporadic IPF) and 25 patients with other diseases as controls for the presence of eight herpesviruses using PCR-based techniques. One or more of four herpesviruses (cytomegalovirus [CMV], EBV, human herpesvirus 7 [HHV-7], and HHV-8) were detected in 32 of 33 (97%) subjects with IPF and in 9 of 25 (36%) controls (P < 0.0001). CMV, EBV, and HHV-8 were found more frequently in IPF patients than in controls (P < 0.05, P < 0.001, and P < 0.01 respectively). Two or more herpesviruses were detected in 19 of 33 (57%) IPF patients and in 2 of 25 (8%) controls (P < 0.001). Two or more herpesviruses and HHV-8 were found more frequently in patients with sporadic IPF than in patients with familial IPF (P < 0.05 for both comparisons), and CMV was found less frequently in patients with sporadic IPF than in patients with familial IPF (P < 0.05). Immunohistochemistry for EBV or HHV-8 antigen showed viral antigen primarily in airway epithelial cells. These data support the concept that a herpesvirus could be a source of chronic antigenic stimulation in IPF.

High rate of false-negative results of the rectal swab culture method in detection of gastrointestinal colonization with vancomycin-resistant enterococci.

The diagnostic accuracy of the rectal swab (RS) culture method in identifying gastrointestinal colonization with vancomycin-resistant enterococci (VRE) is not known. Serial quantitative stool cultures, skin cultures, and RS cultures were performed for patients with VRE infections to assess the false-negative rate of the RS and the prevalence of skin colonization, a prerequisite for cross-transmission, at varying VRE stool densities. A total of 35 stool samples were obtained from 13 patients. The sensitivity of the RS culture was 58%; it ranged from 100%, at VRE densities of > or =7.5 log10 colony forming units (cfu) per gram of stool, to 0%, at densities of < or =4.5 log10 cfu per gram of stool. Skin colonization was detected at these low VRE stool densities, but it was more common at higher VRE densities (P<.001). Antibiotic exposure was significantly associated with higher VRE stool densities (P<.001). The high false-negative rate of the RS may be contributing to the continued increase in the prevalence of VRE.

High Interlaboratory Reproducibility of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry-Based Species Identification of Nonfermenting Bacteria

ABSTRACT Matrix-assisted laser desorption ionization-time of flight mass spectrometry has emerged as a rapid, cost-effective alternative for bacterial species identification. Identifying 60 blind-coded nonfermenting bacteria samples, this international study (using eight laboratories) achieved 98.75% interlaboratory reproducibility. Only 6 of the 480 samples were misidentified due to interchanges (4 samples) or contamination (1 sample) or not identified because of insufficient signal intensity (1 sample).

Anti-IL-4 treatment at immunization modulates cytokine expression, reduces illness, and increases cytotoxic T lymphocyte activity in mice challenged with respiratory syncytial virus.

Upon respiratory syncytial virus (RSV) challenge, mice previously immunized intramuscularly with inactivated whole virus express a Th2-like pattern of cytokine mRNA, while mice immunized with live virus intranasally express a Th1-like pattern. In this study, we evaluated the effects of anti-IL-4 treatment on the induction of immune responses after immunization. Mice treated with anti-IL-4 at the time of immunization with inactivated RSV had reduced clinical illness after live virus challenge, as measured by weight loss, illness score, and virus replication. This was associated with an augmented CD8+ cytotoxic T lymphocyte (CTL) activity, increased expression of IFN-gamma mRNA relative to IL-4 mRNA, and a higher titer of RSV-specific IgG2a in the anti-IL-4 treated mice before challenge. Anti-IL-4 administration at the time of challenge had no effects on illness, immunoglobulin isotype, or cytokine patterns. These results suggest that inhibition of IL-4 action at immunization can shift the selective activation of lymphocytes to a more Th1-like response. This cytokine milieu is associated with augmented CTL activity, which may be the factor responsible for rapid viral clearance and reduced illness at the time of remote RSV challenge.

Bordetella holmesii-Like Organisms Associated with Septicemia, Endocarditis, and Respiratory Failure

We recovered an unusual bacterial strain from blood or sputum of three patients with septicemia, endocarditis, and/or respiratory failure. The three isolates were thin, curved, gram-negative, light brown, pigment-producing bacilli with variable catalase activity. They were asaccharolytic, oxidase-negative, nonmotile, and fastidious. Identification was not possible on the basis of these characteristics alone or in combination with cellular fatty acid profiles. Nucleic acid amplification and sequence analysis of the 16S rRNA gene revealed that all three isolates were identical and most closely related to the emerging pathogen Bordetella holmesii, diverging from the published sequence at three nucleotide positions (99.8% similarity). Isolation of a B. holmesii-like pathogen from sputum suggests that, in addition to producing septicemia, the organism may inhabit the respiratory tract like other Bordetella species.

C. Diff Quik Chek Complete Enzyme Immunoassay Provides a Reliable First-Line Method for Detection of Clostridium difficile in Stool Specimens

ABSTRACT We evaluated a single membrane device assay for simultaneously detecting both Clostridium difficile glutamate dehydrogenase (GDH) and toxin A/B antigens against a standard that combines two PCR assays and cytotoxigenic culture. Results showing dual GDH and toxin A/B antigen positives and negatives can be reported immediately as true positives and negatives, respectively. Specimens with discrepant results for GDH and toxins A/B, which comprised 13.2% of the specimens, need to be retested.

Vancomycin-Resistant Enterococci among Chronic Hemodialysis Patients: A Prospective Study of Acquisition

To determine the prevalence and rate of acquisition of vancomycin-resistant enterococci (VRE) among patients undergoing chronic (i.e., long-term) hemodialysis who were admitted to a tertiary care center, serial rectal cultures for VRE were performed at hospital admission and every 5 days until hospital discharge. A total of 7 (6%) of the 119 patients were colonized with VRE at admission. Six (19%) of the 32 patients who remained in the hospital > or =4 days acquired VRE. A nonambulatory status was significantly associated with colonization at admission (OR, 9.7; 95% CI, 1.8-53; P=.01), and vancomycin exposure was significantly associated with VRE acquisition (relative risk, 1.8; 95% CI, 1.1-2.9; P=.02). All patients acquired VRE from epidemiologically linked dialysis patients colonized with similar VRE genotypes. Hospital acquisition of VRE contributes substantially to the increasing prevalence of VRE in the chronic hemodialysis patient population.

Dual Infections of the Central Nervous System with Epstein-Barr Virus

We describe clinical and laboratory characteristics of 16 patients with central nervous system (CNS) infection caused by Epstein-Barr virus (EBV) and another pathogen. Seven of 10 immunocompromised patients had coinfection with viruses (3 with cytomegalovirus, 2 with JC virus, and 2 with varicella zoster virus) and 3 with nonviral pathogens (2 with pneumococcus and 1 with Cryptococcus species). Three of 6 immunocompetent patients had coinfections with viruses (1 each with herpes simplex virus, varicella zoster virus, and West Nile virus), and 3 had coinfections with nonviral pathogens (2 with Ehrlichia chaffeensis and 1 with Mycoplasma pneumoniae). The EBV load was similar in immunocompromised and immunocompetent patients and in patients with viral and nonviral coinfections. EBV lytic-cycle mRNA was detected in the cerebrospinal fluid of 5 of 6 tested samples, indicating EBV replication in the CNS during coinfection.

Adjuvants influence the quantitative and qualitative immune response in BALBc mice immunized with respiratory syncytial virus FG subunit vaccine

The ability of monophosphoryl lipid A (MPL), QS-21 and alum to alter the immunologic response to immunization with respiratory syncytial virus a chimeric FG construct (FG) subunit vaccine was examined in BALB/c mice. FG/MPL, FG/alum, and FG/MPL/QS-21 combinations increased non-neutralizing antibody response, while FG/QS-21 did not. FG subunit vaccine with MPL, QS-21, or both had cytokine responses more closely resembling primary infection than FG/alum, with decreased interleukin-4 mRNA levels and increased IgG2a isotype antibody. The lungs of the mice immunized with FG subunit vaccines showed a heightened inflammatory response to respiratory syncytial virus challenge as compared to live virus immunization. Adjuvants can be used to alter the humoral and cellular responses to RSV subunit immunization.

Comparative Evaluation of Three Commercial Systems for Nucleic Acid Extraction from Urine Specimens

ABSTRACT A nucleic acid extraction system that can handle small numbers of specimens with a short test turnaround time and short hands-on time is desirable for emergent testing. We performed a comparative validation on three systems: the MagNA Pure compact system (Compact), the NucliSens miniMAG extraction instrument (miniMAG), and the BioRobot EZ1 system (EZ1). A total of 75 urine specimens submitted for polyomavirus BK virus detection were used. The human β-actin gene was detected on 75 (100%), 75 (100%), and 72 (96%) nucleic acid extracts prepared by the miniMAG, EZ1, and Compact, respectively. The miniMAG produced the highest quantity of nucleic acids and the best precision among the three systems. The agreement rate was 100% for BKV detection on nucleic acid extracts prepared by the three extraction systems. When a full panel of specimens was run, the hands-on time and test turnaround time were 105.7 and 121.1 min for miniMAG, 6.1 and 22.6 min for EZ1, and 7.4 and 33.7 min for Compact, respectively. The EZ1 and Compact systems processed automatic nucleic acid extraction properly, providing a good solution to the need for sporadic but emergent specimen detection. The miniMAG yielded the highest quantity of nucleic acids, suggesting that this system would be the best for specimens containing a low number of microorganisms of interest.