Evaluation of the shell vial technique for detection of ocular adenovirus. Community Ophthalmologists of Pittsburgh, Pennsylvania

Point-of-Care Testing for Pandemic Influenza and Biothreats

New and reemerging infectious diseases, such as pandemic viruses and resistant bacteria, pose a serious threat in the 21st century. Some of these agents represent global security threats. This review provides an overview of diagnostic challenges presented by pandemic influenza and biothreat agents. The article summarizes recent pandemics and disease outbreaks, point-of-care influenza diagnostic tests, biothreat agents, biothreat instrument systems, and technologies in development. It highlights how medical innovation and health care initiatives can help prepare health care professionals and public health personnel to handle future crises. Based on gap analysis for current point-of-care testing deficiencies, it concludes with policy recommendations that will enhance preparedness. (Disaster Med Public Health Preparedness. 2009;3(Suppl 2):S193–S202)

Epidemic adenoviral keratoconjunctivitis possibly related to ophthalmological procedures in a neonatal intensive care unit: lessons from an outbreak

PURPOSE

Epidemic adenoviral keratoconjunctivitis can spread rapidly among preterm infants who frequently undergo ophthalmological examination. Here we present our experience on a nosocomial outbreak that affected 8 nursery staff members and 26 premature infants. We focus on the presentation and progress of the outbreak, the diagnosis of the disease and the measures taken for its control.

METHODS

Data were collected from patients' files and records of the infection control team. Conjunctival swabs were collected to perform direct fluorescent assay (DFA) and viral culture. Diagnosis was made according to clinical evidence and/or detection of the virus. Statistical analysis was performed using SPSS 15.0 statistical software.

RESULTS

Infection was introduced to our unit after a laser photocoagulation procedure of a 28-week gestational infant and circulated rapidly within the unit due to direct transmission through contaminated medical equipment, fomites and hands of nursery staff members. Neither the patients, nor the nursery staff members developed systemic symptoms. While DFA tests were positive in seven infants, culture positivity could be demonstrated in only three infants. Contact and droplet precautions were implemented with the recommendation of the infection control team. No recurrence occurred after definition of the last case on the 32nd day.

CONCLUSION

Ophthalmologic procedures continue to be a potential source of adenovirus outbreaks. However, negligence of contact measures during routine daily nursing care seems to be a more important contributing factor for rapid spread. Strict adherence to appropriate aseptic procedures is required to prevent this potentially hazardous infection in preterm infants.

Feasibility of an antiviral clinical trial requiring cross-country shipment of conjunctival adenovirus cultures and recovery of infectious virus

PURPOSE

Accurate and timely laboratory diagnosis of adenovirus from conjunctival cultures is essential to ensure appropriate enrollment, and detection of residual infectious virus is essential to evaluate antiviral efficacy in any multicenter national clinical trial. As part of a feasibility study, we investigated those variables that might affect the successful recovery of infectious adenovirus from patient conjunctival cultures after cross-country shipment.

MATERIALS AND METHODS

Simulated adenovirus conjunctival cultures were prepared in viral transport media to evaluate the effect of four variables (adenovirus serotype, initial concentration, initial storage temperature [-20 degrees C, 0 degrees C, 20 degrees C], and preshipment storage times [1-5 days]) on the recovery of infectious adenovirus by a central laboratory in St. Paul, MN, following air shipment from Pittsburgh, PA. Upon arrival, the internal temperatures of the containers were recorded, and the samples were cultured on A549 cells using standard tube and/or shell vial culture.

RESULTS

Overall, adenovirus was recovered in 352/354 (99.4%) of the samples when the initial titer was greater than 1.0 PFU/ml. Adenovirus serotype, initial storage temperature, and preshipment storage times had no adverse effect on virus recovery.

CONCLUSIONS

Simulated conjunctival samples could successfully be shipped cross-country at ambient temperatures to a commercial laboratory for adenovirus isolation by culture. Having demonstrated feasibility, a clinical trial was subsequently carried out that confirmed the ease of shipment and recovery of infectious adenovirus from conjunctival cultures.

A comparison of methods for detecting adenovirus type 8 keratoconjunctivitis during a nosocomial outbreak in a Neonatal Intensive Care Unit

BACKGROUND

An outbreak of epidemic keratoconjunctivitis (EKC) due to adenovirus (Ad) type 8 and involving 14 members of the hospital staff and 33 neonates admitted to the Neonatal Intensive Care Unit of the local University Hospital occurred between September and December 2000 in Pavia, Italy. The outbreak was preceded by an outbreak of EKC within the community.

OBJECTIVE

To compare the performance of conventional virus isolation on cell cultures, direct detection of Ad antigens in conjunctival cells by a direct fluorescent assay (DFA) and Ad DNA detection in conjunctival swabs by polymerase chain reaction (PCR) for diagnosis of adenoviral conjunctivitis.

STUDY DESIGN

Of conjunctival swabs collected from 47 patients, all were tested by virus isolation, 43 by direct Ad antigen detection, and 37 by Ad DNA detection. Direct Ad antigen detection was carried out by DFA using a group-specific monoclonal antibody. Detection and subgrouping of Ad DNA by nested PCR was performed using two sets of primers complementary to hexon and fiber genes, respectively.

RESULTS

Ad was detected in 24/47 (51.1%), 21/43 (48.8%), and 23/37 (62.1%) samples by virus isolation, direct antigen detection and PCR, respectively. Overall, 30/47 (63.8%) samples were Ad-positive. Of 37 specimens tested in parallel by all three methods, Ad was detected by at least one of the three techniques in 26/37 (70.3%). All Ad isolates were identified as serotype 8 by neutralization, while all PCR-positive samples were identified as belonging to subgroup D. No other virus was isolated from any conjunctival swab. Time required for test completion was 9.6 (4-20) days for virus isolation, 1-2 h for DFA and 24 h for PCR.

CONCLUSIONS

DFA was a sensitive and rapid assay but results depend on the quality of sample and the expertise of the observer. PCR was the most sensitive assay, although it takes longer to perform and requires dedicated facilities; thus, it could be restricted to DFA-negative samples. Virus isolation is still useful from an epidemiological point of view.

Comparison of an immortalized human corneal epithelial cell line with Vero cells in the isolation of Herpes simplex virus-1 for the laboratory diagnosis of Herpes simplex keratitis

BACKGROUND

Herpes simplex keratitis (HSK) is a sight threatening ocular infection often requiring a specific and prompt laboratory diagnosis. Isolation of Herpes simplex virus (HSV-1) in culture provides the most reliable and specific method and is considered as the "Gold Standard" in the laboratory diagnosis of HSK in spite of its low sensitivity. Using "cell lines of corneal origin" for virus isolation may be beneficial under such circumstances, since these cells have been shown to be excellent substrates for the growth of HSV-1 isolated from the cornea. We report a comparative study of a novel human corneal epithelial cell line (HCE) and the Vero cell line in the isolation of HSV-1 from corneal scrapings employing a shell vial assay.

METHODS

Corneal scrapings were obtained from 17 patients with a clinical diagnosis of HSK. All the cases were confirmed by virological investigations (PCR and viral antigen detection positive, n = 15, PCR positive, n = 1, Viral antigen positive, n = 1). Scrapings obtained from 10 patients with infectious keratitis of non-viral origin were included as controls. All the scrapings were simultaneously inoculated into shell vials of HCE and Vero cells. Cultures were terminated at 24 h post-infection. Isolation of HSV-1 was confirmed using an indirect immunofluorescence/ immunoperoxidase assay.

RESULTS

Virus could be isolated using both or either of the cell lines in 10/17 (58.82%) patients with HSK. HSV-1 was isolated from 10/17 (58.82%) and 4/17(23.52%) specimens in HCE and Vero cells, respectively (P = 0.036). None of the controls yielded HSV-1. While all the 10 (100%) strains were isolated in HCE, Vero yielded only 4/10 (40%) strains in the shell vial culture (P = 0.014).

CONCLUSIONS

HCE showed a statistically significant difference in the virus isolation rate with respect to Vero cells. HCE may be an excellent alternative cell line for the isolation of HSV-1, especially from corneal scrapings, for the laboratory diagnosis of HSK.

The disinfection of contact lenses contaminated with adenovirus

PURPOSE

We compared the efficacy of different contact lens disinfection systems to eliminate adenovirus.

METHODS

Laboratory study evaluating the elimination of adenoviral ocular isolates by contact lens disinfection systems. Hard (gas permeable) and soft contact lenses were contaminated with adenovirus serotypes 8 and 19, and then they were disinfected with chemical, hydrogen peroxide, and heat sterilization systems. The survival of the adenovirus was determined by the shell vial technique.

RESULTS

Adenovirus survived chemical and hydrogen peroxide disinfection but not heat sterilization.

CONCLUSION

Because heat sterilization is not readily available to sterilize adenovirus contaminated contact lenses, it may be prudent for patients with adenoviral keratoconjunctivitis to dispose of unclean contact lenses.

Ex vivo adenovirus mediated gene transfection of human conjunctival epithelium

AIM

To investigate the efficacy of "ex vivo" adenoviral vector mediated gene transfection of human conjunctival epithelial cell as a possible route for gene therapy for the distribution of anti-inflammatory agents for the potential treatment of immune mediated ocular inflammatory disorders.

METHODS

Human conjunctival cells (HCs) were cultured with various concentrations of recombinant adenoviral vectors carrying a reporter gene LacZ, GFP, or an immunomodulating cytokine vIL-10. vIL-10 in culture supernatant was detected by sandwich ELISA and biological activity was assessed by suppression of ConA stimulated splenocyte proliferation. X-gal and GFP expression was assessed by histochemistry.

RESULTS

The extent of adenoviral vector mediated transfer of both reporter genes and vIL-10 was dose dependent. LacZ expression could be detected for at least 50 day after infection with multiple of infection (MOI) 200. Following AdCMVvIL-10 transduction, vIL-10 protein expression occurred between 4-6 days post-transduction, and was maintained at a detectable level for at least 1 month. Secreted vIL-10 showed biological activity, significantly inhibiting Con A induced splenocyte proliferation. Additionally, transfection of HCs with two Adv vectors, one carrying LacZ and the other carrying GFP, resulted in co-expression within a single cell.

CONCLUSION

These results confirm previous successful adenoviral vector mediated gene transfer to HCs and further show that expression can be maintained. Furthermore the data show HCs can secrete biologically active vIL-10 that could be developed as a strategy to suppress immune mediated disorders. The successful co-transduction of HCs as described for other tissues, opens avenues to develop a multiple target gene therapy locally.