Isolation of a novel intertypic recombinant human mastadenovirus B2 from two unrelated bone marrow transplant recipients.

Human adenoviruses (HAdV) are well-known opportunistic pathogens of immunocompromised adult and pediatric patients but specific associations between HAdV species or individual HAdV types and disease are poorly understood. In this study we report the isolation of a novel HAdV-B2 genotype from two unrelated immunocompromised patients, both recipients of a hematopoietic cell transplant. In both patients, the course of HAdV infection is consistent with a scenario of reactivation of a latent virus rather than a primary opportunistic infection. Archived HAdV PCR-positive plasma, urine, and stool specimens were processed for virus isolation and detailed molecular characterization. Virus isolates were recovered from patient 1 from PCR-positive urine specimens obtained at days 103 and 116 after transplant in association with gross hematuria, and from a stool specimen obtained 138 days after transplant in association with diarrhea. An isolate was recovered from patient 2 from a PCR-positive urine specimen. Hexon and fiber gene amplification and sequencing were carried out for initial molecular typing, identifying the isolates as an intertypic recombinant with a HAdV-11-like hexon gene and a HAdV-77-like fiber gene. Comprehensive restriction fragment length polymorphism (RFLP) analysis was performed on viral DNA purified from urine and stool isolates, and next generation whole genome sequencing was carried out on purified viral genomic DNA. The genomes of the two isolated strains are 99.5% identical and represent the same RFLP genomic variant. The identified virus is a novel HAdV-B2 genotype designated HAdV-78 exhibiting a HAdV-11-like penton base, a HAdV-11-like hexon and a HAdV-77-like fiber (P11H11F77).

Incidence of respiratory viral infection in infants with respiratory symptoms evaluated for late-onset sepsis.

OBJECTIVE: To determine the frequency, etiology and impact of respiratory viral infection (RVI) on infants evaluated for late-onset sepsis (LOS), defined as sepsis occurring >72 h of life, in the neonatal intensive care unit. STUDY DESIGN: Prospective observational study conducted from 6 March 2014 to 3 May 2016 on infants evaluated for LOS. PCR viral panel performed on nasopharyngeal specimens among infants with clinical suspicion for RVI. Sequence analysis was performed to determine viral subtypes. Fisher's exact or χ2 tests were done to determine the impact of RVI. RESULTS: During the 26-month study, there were 357 blood cultures obtained for LOS evaluations, 29 (8%) had a respiratory virus detected. Only 88 (25%) of infants evaluated for LOS also had clinical suspicion for a respiratory viral infection. RSV (14 of 29; 48%) was the predominant virus detected. Almost all infants (13 of 14; 93%) with RSV required increased respiratory support. Antimicrobial therapy was withheld or discontinued on most infants with a virus detected (18 of 29; 62%) and in the majority where there was no confirmed bacterial co-infection (18 of 20; 90%). CONCLUSION: The incidence of RVI in infants being evaluated for LOS is about 8%. RVI should be considered in LOS evaluation to prevent unnecessary antibiotic therapy.

Standardizing the influenza neuraminidase inhibition assay among United States public health laboratories conducting virological surveillance.

BACKGROUND: Monitoring influenza virus susceptibility to neuraminidase (NA) inhibitors (NAIs) is vital for detecting drug-resistant variants, and is primarily assessed using NA inhibition (NI) assays, supplemented by NA sequence analysis. However, differences in NI testing methodologies between surveillance laboratories results in variability of 50% inhibitory concentration (IC50) values, which impacts data sharing, reporting and interpretation. In 2011, the Centers for Disease Control and Prevention (CDC), in collaboration with the Association for Public Health Laboratories (APHL) spearheaded efforts to standardize fluorescence-based NI assay testing in the United States (U.S.), with the goal of achieving consistency of IC50 data. METHODS: For the standardization process, three participating state public health laboratories (PHLs), designated as National Surveillance Reference Centers for Influenza (NSRC-Is), assessed the NAI susceptibility of the 2011-12 CDC reference virus panel using stepwise procedures, with support from the CDC reference laboratory. Next, the NSRC-Is assessed the NAI susceptibility of season 2011-12 U.S. influenza surveillance isolates (n = 940), with a large subset (n = 742) tested in parallel by CDC. Subsequently, U.S. influenza surveillance isolates (n = 9629) circulating during the next three influenza seasons (2012-15), were independently tested by the three NSRC-Is (n = 7331) and CDC (n = 2298). RESULTS: The NI assay IC50s generated by respective NSRC-Is using viruses and drugs prepared by CDC were similar to those obtained with viruses and drugs prepared in-house, and were uniform between laboratories. IC50s for U.S. surveillance isolates tested during four consecutive influenza seasons (2011-15) were consistent from season to season, within and between laboratories. CONCLUSION: These results show that the NI assay is robust enough to be standardized, marking the first time IC50 data have been normalized across multiple laboratories, and used for U.S. national NAI susceptibility surveillance.

Cytomegalovirus PP65 antigenemia monitoring as a guide for preemptive therapy: a cost effective strategy for prevention of cytomegalovirus disease in adult liver transplant recipients.

BACKGROUND: The aim of the study was to assess the incidence of cytomegalovirus (CMV) infection and disease in adult liver transplant recipients, using routine preemptive therapy guided by the pp65 antigenemia test. METHODS: Antigenemia was monitored weekly after liver transplantation (OLTX) for the first 3 months, and once a month for another 3 months. CMV seronegative recipients were treated preemptively for the first positive antigenemia. Seropositive recipients were treated only when their antigenemia count reached a threshold of > or =100 positive cells per 200,000 leukocytes. RESULTS: A total of 144 patients were included between June 1994 and April 1995, of which 137 (95%) were primary OLTX. The percentage of positive antigenemia and CMV disease was 55 and 8%, respectively. Seventy-eight (54%) patients were protocol-monitored for the entire follow-up (group 1) and received appropriate preemptive therapy, although 66 (46%) patients had protocol violation by having missed blood samples or blood drawn at unscheduled times (group 2). Using Cox's proportional hazards model, patients with a first antigenemia count of >11 leukocytes had a significantly higher rate of CMV disease compared to patients with an antigenemia count < or =11 leukocytes (RR = 7.3, 95% confidence interval = 2.2 to 24.5). In a multivariate Cox regression analysis, adjustments were made to control for: group 1 versus group 2, use of OKT3, and serology risk categories. This analysis showed that the relative rate of CMV disease was still significantly higher among patients with antigenemia count >11 leukocytes (adjusted RR = 4.9, 95% confidence interval = 1.3 to 18.1). The estimated cost of preemptive therapy was less than that of prophylaxis with i.v. (14-day course) or oral (90-day course) ganciclovir. CONCLUSIONS: Preemptive therapy guided by pp65 antigenemia is a useful and cost effective strategy for prevention of CMV disease.

Effects of enhancing agents on detection of cytomegalovirus in clinical specimens.

Dimethyl sulfoxide, dexamethasone, and calcium were tested in combination for their enhancing effects on cytomegalovirus detection in shell vial cultures on 1,579 clinical specimens obtained primarily from adult solid-organ transplant recipients. Fluorescent-focus counts were elevated for the cytomegalovirus-positive urine specimens (P < 0.01) and throat washings (P < 0.05) but not for the tissue biopsy or blood samples. Epidermal growth factor also increased focus counts but provided no additional benefit when used in combination with the other agents. The triple-combination treatment did not increase the number of positive specimens identified.

Comparison of commercially available antibody reagents for the cytomegalovirus pp65 antigenemia assay.

BACKGROUND: The Argene Biosoft 1C3 and the Biotest C10,C11 monoclonal antibodies are two of the most commonly used commercially available antibody reagents for the cytomegalovirus (CMV) pp65 antigenemia assay. OBJECTIVES: The sensitivities of these two reagents were compared in peripheral blood specimens received for CMV antigenemia testing. STUDY DESIGN: A total of 1149 peripheral blood specimens were processed for CMV antigenemia testing. Duplicate slides were stained with the Biosoft 1C3 and Biotest C10,C11 monoclonal antibodies. RESULTS: A total of 158 specimens gave a positive result by one or both antibodies. One hundred and forty five were positive by the Biosoft antibody and 130 were positive by the Biotest antibody. Positive cell counts were significantly higher on cell preparations stained by the Biosoft antibody (Wilcoxon signed rank, P < 0.001) and the Biosoft antibody detected twice as many low-level positive specimens as the Biotest. CONCLUSIONS: The Biosoft antibody reagent was superior to the Biotest reagent for the detection of CMV antigenemia. This is an important factor since early detection is essential for appropriate initiation of preemptive antiviral therapy, particularly in transplant recipients at high risk of CMV disease.

Comparison of monoclonal antibodies for immunostaining in the cytomegalovirus shell vial assay on 4,388 specimens.

The shell vial assay is a sensitive, rapid test for the detection of cytomegalovirus (CMV) in a variety of specimens. The sensitivity of this assay is dependent on a number of factors including the antibodies used for immunostaining. Monoclonal antibodies to the CMV major immediate-early antigen (p72) from Chemicon (MAB810) and Dupont (NEA-9221) were assessed side by side in duplicate vials on 4,388 specimens from a patient population consisting of > 90% organ transplant recipients. A total of 240 specimens (5.5%) were CMV positive in either one or both vials. Positivity rates were variable across different specimen types but highest (12.9%) in urine specimens. Of the positive specimens, 175 (72.9%) tested positive in both vials, 43 (17.9%) tested positive in the Chemicon-stained vial only, and 22 (9.2%) tested positive in the Dupont-stained vial only (P < 0.01, McNemar's chi-square test). This gave an overall positivity rate of 5.0% for Chemicon antibodies and 4.5% for Dupont. There was no difference in the fluorescent focus counts produced by the two antibody sets. It is concluded that use of the Chemicon antibodies provides increased sensitivity of detection of CMV in the shell vial assay above that afforded by the Dupont antibody.

Comparison of cytomegalovirus antigenemia and culture assays in patients on and off antiviral therapy.

We examined 1,869 consecutive blood specimens from 529 patients (>80% organ transplant recipients) for detection of CMV by antigenemia and culture assays, and compared results between patients on and off antiviral therapy. All 1,869 specimens were tested by the shell vial assay and antigenemia, and 503 were also tested by standard tube culture. The overall positivity rate for each test was 17.0% for antigenemia, 1.8% for shell vial culture assay, and 0.7% by tube culture. No specimens were positive by either shell vial or tube culture, while negative by antigenemia. These findings were consistent across all organ transplant and other patient types. Shell vial positivity was associated with higher antigenemia levels in patients either on or off anti-CMV drug therapy. Among the shell vial positive specimens, the antigenemia counts were higher in patients on antiviral drug therapy as compared to those not on therapy. We conclude that the pp65 antigenemia assay is superior to culture methods for detection of CMV in blood, particularly for patients on anti-CMV drug treatment. Additionally, its quantitative nature renders the antigenemia assay an excellent tracking tool for both resolution of asymptomatic, low level CMV reactivations and response of CMV infection to antiviral treatment.

Diagnosis of cytomegalovirus infections by shell vial assay and conventional cell culture during antiviral prophylaxis.

A total of 3,552 specimens for conventional cytomegalovirus (CMV) culture and shell vial assay for CMV immediate-early antigen were obtained during a prospective randomized trial for prophylaxis of CMV disease after liver transplantation. Prophylaxis with ganciclovir for 2 weeks and then high-dose acyclovir for 2.5 months was compared with high-dose acyclovir alone for 3 months. During the first 12 weeks after transplantation, when the patients were on prophylaxis, there were significantly more clinical samples positive by the shell vial assay and negative by standard culture in comparison with the number of samples obtained from weeks 13 to 24, after prophylaxis was discontinued, that were positive by the shell vial assay and negative by standard culture. In contrast, significantly fewer samples were positive by both the shell vial assay and standard culture during the first 12 weeks compared with the number obtained 13 to 24 weeks after transplantation that were positive by both methods. Samples positive by the shell vial assay only were obtained significantly more frequently from patients with asymptomatic than symptomatic CMV infections, while samples positive by both methods were obtained significantly more often from patients with symptomatic CMV infection. It was concluded that antiviral prophylaxis with high-dose acyclovir or ganciclovir and then high-dose acyclovir and asymptomatic CMV infection are associated with a decrease in the level of CMV isolation by standard cell culture in comparison with that by the shell vial assay.

Detection of infectious baboon cytomegalovirus after baboon-to-human liver xenotransplantation.

Xenotransplantation is considered to be a solution for the human donor shortage. However, there is a potential risk of transmitting animal infections from the transplanted organ. The known transmissibility and clinical significance of human cytomegalovirus (HCMV) infection after allotransplantation led us to evaluate whether baboon cytomegalovirus (BCMV) transmission could occur after a baboon-to-human liver xenotransplant. We examined serial blood samples from a baboon liver recipient and isolated replication-competent CMV-like agents on days 29, 36, and 42 after xenotransplantation. BCMV and HCMV DNAs were detected in the day 29 isolate, while only HCMV DNA was detected in the other isolates. This is the first report of detecting a replication-competent virus from a source animal after xenotransplantation and is a concern with regard to potential zoonotic transmission to others.

Prevention of CMV disease in allogeneic BMT recipients by cytomegalovirus antigenemia-guided preemptive ganciclovir therapy.

PURPOSE: Cytomegalovirus (CMV) infection can cause severe disease and mortality in recipients of allogeneic bone marrow transplants (alloBMT) when either the donor or recipient is CMV seropositive (high-risk alloBMT). We investigated the efficacy of preemptive therapy guided by detection of CMV antigenemia. METHODS: In 11 high-risk alloBMT recipients, high-dose ganciclovir (GCV) treatment was initiated at first positive antigenemia and was continued until antigenemia became negative. RESULTS: The treatment strategy prevented CMV disease during the follow-up period of the study in 7 alloBMT recipients with positive CMV antigenemia. Three other patients who were shown to be CMV antigenemia negative but positive for CMV DNA in blood by the polymerase chain reaction (PCR) were not treated and did not develop CMV disease. The eleventh patient was negative for CMV by all tests for the duration of the study and did not develop CMV disease. CONCLUSIONS: We have found antigenemia-guided preemptive GCV therapy to be an effective strategy for the prevention of CMV disease in high-risk alloBMT recipients.

Prevalence of chlamydia and gonorrhoea among a population of men who have sex with men.

OBJECTIVES: Few data are available on the prevalence of sexually transmitted diseases (STDs) in men who have sex with men (MSM), making it difficult to develop STD screening guidelines for this population. The objective of the study was to determine the prevalence of urethral infections caused by Chlamydia trachomatis and Neisseria gonorrhoeae within a large, community based population of MSM, and to assess the feasibility of rectal screening in this population. METHODS: This was a cross sectional study of 566 MSM, who were predominantly middle aged, white, asymptomatic, and engaged in sex with multiple partners. All provided a urine sample to screen for chlamydial and gonorrhoea infections using a PCR assay; rectal screening was performed on 48 participants. RESULTS: Urethral C. trachomatis infections were detected in 1/566 participants (prevalence 0.2%, 95% CI 0.004% to 1.0%), and rectal C. trachomatis infections were detected in 2/48 men (prevalence 4.2%, 95% CI 0.5% to 14.2%). No gonorrhoea infections were detected, and none of the 117 HIV positive men had either infection. CONCLUSIONS: Chlamydial and gonorrhoea infections were uncommon in this sample of MSM, even among those with multiple sexual partners or HIV infection. These data call into question recommendations to screen all MSM based on their individual sexual behaviours or HIV. Additional data are needed on the prevalence of these infections in MSM from different settings.

Screening for Chlamydia trachomatis infection in college women with a polymerase chain reaction assay.

This study sought to determine factors associated with chlamydial infection in a low-prevalence college health setting and to determine the testing characteristics of a polymerase chain reaction (PCR) assay for chlamydial infection (AMPLICOR chlamydia test; Roche Diagnostic Systems, Indianapolis) in this population. Young women (n = 1,149) at a university student health clinic underwent testing for cervical chlamydial infection by PCR assay and culture; the characteristics of women with and without chlamydial infection were compared. Chlamydial infection was diagnosed for 26 students (2.3%). The sensitivity and specificity of PCR assay and culture were 85% and 100% and 54% and 100%, respectively. Students with chlamydial infection were more likely to be 20 years of age or younger, have symptoms, report prior chlamydial infection or gonorrhea, report exposure to a sexually transmitted disease (STD), be black, or have cervical signs during examination; however, none of these were significant predictors for asymptomatic women. PCR assay detected significantly more cervical infections than did culture in this college student population. These data are consistent with recommendations for testing college women with symptoms, STD exposure, or age of younger than 25 years.

Comparison of quantitative cytomegalovirus (CMV) PCR in plasma and CMV antigenemia assay: clinical utility of the prototype AMPLICOR CMV MONITOR test in transplant recipients.

The correlation between the prototype AMPLICOR CMV MONITOR test (Roche Molecular Systems), a quantitative PCR assay, and the cytomegalovirus (CMV) pp65 antigenemia assay was evaluated in transplant recipients. Sequential blood specimens were collected on 29 patients (491 specimens), the leukocyte fraction was tested by CMV antigenemia, and quantitative PCR was performed on plasma specimens. None of the 15 patients (242 specimens) who were antigenemia negative were positive for CMV DNA by PCR, and none of these patients developed active CMV disease. There were 14 antigenemia-positive patients, 8 of whom developed active CMV disease. In all patients, there was a good association between the antigenemia and PCR assays. Ganciclovir-resistant virus was isolated from three patients with active CMV disease. These three patients had persistently elevated levels of antigenemia and CMV DNA by PCR when resistance to ganciclovir developed. This standardized, quantitative CMV PCR assay on plasma has clinical utility for the diagnosis of active disease and in monitoring the response to antiviral therapy in transplant recipients.

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.

Distinguishing baboon cytomegalovirus from human cytomegalovirus: importance for xenotransplantation.

The severe shortage of human organs for transplantation is the driving force behind xenotransplant research. Nonhuman primates, particularly baboons, are potential sources of organs and tissues. Human cytomegalovirus (HCMV) is the most common donor-associated infection after allotransplantation. Baboon cytomegalovirus (BCMV) is endemic in baboon populations and therefore is a potential cause of donor-associated disease after xenotransplantation. Accordingly, the ability for BCMV to grow in human cells was determined and a sensitive method to distinguish BCMV from HCMV was developed. Human fibroblasts were permissive for BCMV, isolates exhibited cytopathology characteristic of HCMV, and herpesvirus-like virions were observed by electron microscopy. BCMV and HCMV could be distinguished by restriction fragment length polymorphism patterns and by polymerase chain reaction with primers targeting the BCMV major immediate-early gene promoter. These methods can be used to evaluate BCMV pathogenicity in laboratory and clinical xenotransplant trials.