Performance Validation of the Microbiologique Microfilm Test System for AOAC Research Institute .

The Microfilm™ Test System is intended for quantitative microbiology and consists of three types of Microfilms for aerobic plate count (Microfilm APC), total coliform and Escherichia coli count (Microfilm TCEc), and yeast and mold count (Microfilm YMC). This study evaluated the performance of the Microfilm Test System against International Organization for Standardization (ISO) methods on 20 food matrixes and 2 environmental surfaces. Ruggedness, robustness, and stability were also determined, while inclusivity and exclusivity studies were performed on Microfilm TCEc and YMC.

Performance evaluation of a new rapid urine test for chlamydia in men: prospective cohort study.

Objective: To evaluate the performance of a rapid test for chlamydia with first void male urine samples as a potential tool for diagnosis and screening of chlamydial infection in men.

Design: Evaluation of test performance in prospective cohort study. Settings A young people's sexual health centre (site 1) and a genitourinary medicine clinic (site 2) in the United Kingdom.

Evaluation of a new hepatitis B virus surface antigen rapid test with improved sensitivity.

A new rapid immunochromatographic assay based on the signal amplification system (SAS) has been developed by Diagnostics for the Real World (Europe) Ltd. for the detection of hepatitis B virus surface antigen (HBsAg) in plasma or serum specimens. The SAS format features enhanced sensitivity as a result of an increased binding valence of the detector molecules.

Optimal method of collection of first-void urine for diagnosis of Chlamydia trachomatis infection in men.

First-void urine (FVU) is the preferred specimen for the diagnosis of urogenital Chlamydia trachomatis infection in men. We have developed FirstBurst, a urine collection device that collects the first 4 to 5 ml of FVU and yields a specimen with a sixfold higher C. trachomatis organism load than the regular urine cup by quantitative PCR (32,533 versus 5,271 plasmids/ml; P < 0.

Prevalence of Chlamydia trachomatis infection among low- and high-risk Filipino women and performance of Chlamydia rapid tests in resource-limited settings.

The prevalence of urogenital Chlamydia trachomatis infection was determined with a PCR-based test of women from low- and high-risk populations in Iloilo City, Philippines, between August 2002 and March 2006. Two rapid tests for C. trachomatis, Clearview Chlamydia MF and the Chlamydia Rapid Test (CRT), were also evaluated in these resource-limited settings.

Chlamydia trachomatis load at matched anatomic sites: implications for screening strategies.

Urethral and endocervical swabs and self-collected vaginal swabs (SCVSs) and urine specimens are all used as samples for diagnosis of urogenital infection with Chlamydia trachomatis. We have now determined chlamydial organism load in matched specimens from different anatomic sites and examined its relation to clinical signs and symptoms in men and women. Organism load was measured with assays based on the ligase chain reaction or real-time PCR analysis.

Field evaluation of a rapid point-of-care assay for targeting antibiotic treatment for trachoma control: a comparative study.

Background: Trachoma results from repeated episodes of conjunctival infection with Chlamydia trachomatis and is the leading infectious cause of blindness. To eliminate trachoma, control programmes use the SAFE strategy (Surgery, Antibiotics, Face cleanliness, and Environmental improvement). The A component is designed to treat C trachomatis infection, and is initiated on the basis of the prevalence of the clinical sign trachomatous inflammation-follicular (TF).

Conservation of the DNA sequences encoding the major structural viral proteins of WSSV.

A cDNA library was constructed from white spot syndrome virus (WSSV)-infected penaeid shrimp tissue. cDNA clones with WSSV inserts were isolated and sequenced. By comparison with DNA sequences in GenBank, cDNA clones containing sequence identical to those of the WSSV envelope protein VP28 and nucleoprotein VP15 were identified.

Production of polyclonal antiserum specific to the 27.5 kDa envelope protein of white spot syndrome virus.

A truncated version of the white spot syndrome virus (WSSV) 27.5 kDa envelope protein was expressed as a histidine tag fusion protein in Escherichia coli. The bacterial expression system allowed the production of up to 10 mg of purified recombinant protein per liter of bacterial culture.

White spot syndrome virus (WSSV) in cultured Penaeus monodon in the Philippines.

The prevalence and geographic distribution of white spot syndrome virus (WSSV) infection among cultured penaeid shrimp in the Philippines was determined from January to May, 1999, using PCR (polymerase chain reaction) protocol and Western blot assays. A total of 71 samples consisting of 18 post-larvae (PL) and 53 juvenile/adult shrimp samples (56 to 150 days-of-culture, DOC) were screened for WSSV. Of the 71 samples tested, 51 (72%) were found positive for WSSV by PCR: 61% (31/51) after 1-step PCR and 39% (20/51) after 2-step, non-nested PCR.

Dot-blot nitrocellulose enzyme immunoassays for the detection of white-spot virus and yellow-head virus of penaeid shrimp.

Dot-blot nitrocellulose enzyme immunoassays (DB-NC-EIA) were developed for the detection of white-spot virus (WSV) and yellow-head virus (YHV) in infected shrimp. The assays utilized HRP-conjugated virus-specific antibodies to detect virus antigen present in gill homogenates of infected shrimp spotted onto nitrocellulose membrane. The assays are by far the simplest and most rapid detection methods available for WSV and YHV.

A polymerase chain reaction protocol for the detection of various geographical isolates of white spot virus.

Polymerase chain reaction (PCR) primers were designed based on the sequence of a cloned fragment of the white spot virus (WSV) genome and were used to detect at least four geographic isolates of WSV from both experimentally- and naturally-infected shrimp. In addition to high specificity, the one-step and two-step PCR protocols were determined to have sensitivities of 10-100 pg and 100 femtograms respectively. The two-step PCR protocol is recommended as a very sensitive and specific alternative protocol to Western blot assay for the detection of WSV.

A comparative study of three different isolates of white spot virus.

Three separate isolates of white spot virus (WSV) purified from 3 different penaeid shrimp species from different countries were compared morphologically, biochemically, and genomically using the following techniques; negative stain electron microscopy, sodium dodecyl-sulfate polyacrylamide gel electrophoresis/western blot, and restriction fragment length polymorphism (RFLP), respectively. Under the electron microscope, the 3 isolates were indistinguishable. Their nucleoprotein cores exhibited the unique striated structure characteristic of the baculovirus-like agents associated with white spot syndrome.

Characterization of a non-occluded baculovirus-like agent pathogenic to penaeid shrimp.

A non-occluded baculovirus-like agent recently isolated by this laboratory from moribund Penaeus japonicus shrimps obtained from China and named Chinese baculovirus (CBV) was purified and some of its properties characterized. Under the electron microscope, negatively stained virus particles were rod-shaped, enveloped, and measured 322 to 378 nm in length and 130 to 159 nm in diameter. The nucleoprotein core exhibited a unique striated structure and measured 316 to 350 nm in length and 65 to 66 nm in diameter.

Detection of yellowhead virus and Chinese baculovirus in penaeid shrimp by the Western blot technique.

The continuing threat posed by viral diseases in cultured shrimp calls for the development of detection technologies for monitoring the animals, especially broodstock. Two of the most highly pathogenic viruses of penaeid shrimp are the yellow-head virus (YHV) and Chinese baculovirus (CBV, also called white spot baculovirus). A Western blot (WB) protocol capable of detecting YHV and CBV in the hemolymph of infected shrimp was developed.

Development of an in vitro quantal assay in primary cell cultures for a non-occluded baculo-like virus of penaeid shrimp.

An in vitro quantal assay (TCID50) for a non-occluded baculo-like virus isolate from naturally infected Penaeus japonicus obtained from China and experimentally infected P. stylirostris was developed using primary shrimp lymphoid cell cultures in Primaria 24-well tissue culture plates. The virus caused cytopathogenic effect (CPE) in the cell cultures as early as 2 day post-infection (p.

Viral pathogens of the penaeid shrimp.

While significant advances that have been made in determining the role of viruses involved in various epizootics occurring in penned shrimp aquaculture, viral diseases will continue to plague the industry. A major obstacle to the study of these diseases is the lack of convenient and quantitative methodologies, such as cell culture systems to grow and study (characterize) the virus. A beginning has been made with the recent development of protocols for the consistent preparation of primary shrimp lymphoid cells, which were employed for the quanta1 assay of some of the shrimp viral pathogens.

ELISA for the detection of serum and saliva IgA against the BMRFI gene product of Epstein-Barr virus.

The BMRF1 protein is an Epstein-Barr virus (EBV) DNA polymerase accessory protein that forms part of the early antigen diffuse (EA-D) component. An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of IgA antibody to the BMRF1 protein of EBV in saliva and serum samples. The assay was shown to be specific for nasopharyngeal carcinoma (NPC) patients and, when used with saliva alone, to have a sensitivity comparable to an existing indirect immunoperoxidase assay for early antigens.

Transformation of primary cultures of shrimp (Penaeus stylirostris) lymphoid (Oka) organ with Simian virus-40 (T) antigen.

Primary cultures of lymphoid (Oka) organ from Penaeus stylirostris were transformed with naked or Lipofectin-mediated pSV-3 neo, a shuttle vector containing the tumor (T) antigen gene from Simian virus-40. The transformed cells, OKTr-1 and OKTr-23, exhibited the following characteristics: rounded morphology forming grapelike aggregates, loosely adhesive, increased growth rate in Medium-199, resistance to G-418 (a neomycin analog marker in the shuttle vector), cloning efficiencies of 68.7% and 36.

A streptavidin-biotin-enhanced nitrocellulose enzyme immunoassay for the detection of rhabdovirus of penaeid shrimps from infected animals.

A streptavidin-biotin-enhanced nitrocellulose enzyme immunoassay was developed for the detection of the rhabdovirus of penaeid shrimps (RPS) in the tissues of infected animals. Initial tests indicate that the assay was capable of detecting as few as ten plaque-forming units of virus.

Production of high efficiency of plating hepatitis A virus in primary African green monkey kidney cells.

High-titered hepatitis A virus, strain HM-175, was produced in primary African green monkey kidney cells (5.5 x 10(10) tissue culture ID50/850 cm2 roller bottle). The virus preparation had an efficiency of plating of 15 particles per infectious unit.

A new virus isolate from infectious hypodermal and hematopoietic necrosis virus (IHHNV)-infected penaeid shrimps.

A new virus was isolated from infectious hypodermal and hematopoietic necrosis virus (IHHNV)-infected penaeid shrimps. The virus was isolated from two species of penaeid shrimps obtained from three different sources employing a previously developed cell-culture assay. Electron-microscopical studies of both purified virus and infected cells showed bullet-shaped particles identifying it as a rhabdovirus.

Immunofluorescence and immunoperoxidase assays for the titration of infectious hepatitis A virus (HAV).

Immunofluorescence (IFA) and immunoperoxidase (IPA) assays were developed for the titration of infectious hepatitis A virus. Both of these methods were found to be simple, rapid and quantitatively reproducible. The immunoperoxidase technique could be the method of choice for the assay of HAV in cell culture.