Development of a chip-based multiplexed immunoassay using liposomal nanovesicles and its application in the detection of pathogens causing female lower genital tract infections.

OBJECTIVE: Cervicovaginitis is a highly prevalent disease that is a burden on healthcare globally. Immediate and adequate treatment can eradicate the infection and block subsequent complications. The feasibility of achip-based multiplexed immunoassay using liposomal nanovesicles was tested. MATERIALS AND METHODS: A multiplexed immunoassay chip containing five antibodies for five pathogens (Chlamydia trachomatis, Escherichia coli, Neisseria gonorrhoeae, Streptococcus agalactiae, and Candida albicans) was established and tested. Four patients with spiking of candidiasis were enrolled. The difference between positive and negative readings was evaluated using the paired Student t test. RESULTS: The detection threshold of Candida in this microarray was 100,000 CFU/mL in a vaginal sample, and the time required for the whole procedure was 3 hours. The testing of the four patients showed 100% for both sensitivity and specificity. CONCLUSION: This microarray chip was a rapid, easy, inexpensive and sensitive tool for detecting female lower genital tract Candida infection in a one-time vaginal sampling process, although the data on the four other pathogens were still unavailable. A larger population study is encouraged to test the validity of this multiplexed immunoassay chip.

Are we satisfied with the tools for the diagnosis of gonococcal infection in females?

Gonorrhea (Neisseria gonorrhoeae) is a common sexually transmitted infection in women, with a heavy burden on female and neonatal health, because sequelae occur, such as female infertility, ectopic pregnancy, neonatal ophthalmitis and infection, and chronic pelvic pain. Prompt and appropriate antibiotic treatment can cure infection and avoid complications. However, adequate treatment is not easy, because early and rapid identification of gonorrhea is interfered with by many factors, including the complicated mixed microflora of the vagina and cervix, non-user-friendly culture systems, and lack of immediate availability of results, even with a combination of subjective complaint and high clinical suspicion. A PubMed search was conducted using the major headings of "gonorrhoea and diagnostic tool" and "Neisseria gonorrhoeae and diagnostic tool", before the end of 2010. Recently available methods for the diagnosis of gonorrhea infection in women were included, including traditional tools and advanced technology. Traditional tools such as microscopic examination and microbial culture have been used broadly; unfortunately, they have relatively lower specificity or sensitivity, and most importantly, "see-and-treat" is impossible for these infected women. Advances in technology, such as antigen detection by immunoassay and nucleic acid amplification tests (NAATs), have achieved major progress in the diagnosis of gonorrhea, because of their accuracy, convenience and time-saving aspects. However, NAATs are expensive, making their acceptance impossible in developing countries. Detection of pathogens including N. gonorrheae using microarray chips is viewed as a possible solution, because it is a relatively rapid, easy, inexpensive and sensitive tool, which makes an "identify-and-treat" or point-of-care policy possible. A rapid and affordable tool with high sensitivity and specificity for detection of gonorrhea in developing countries is still not available at the time of writing. To make a point-of-care policy possible, advanced technology for aiding diagnosis of gonorrhea is encouraged and appreciated.

Diagnosis of Chlamydia infection in women.

OBJECTS: Chlamydia (Chlamydia trachomatis) is a common sexually transmitted infection that places a heavy burden on women and neonatal health. To avoid severe sequelae such as female infertility, ectopic pregnancy, neonatal infection, such as ophthalmitis, and chronic pelvic pain prompt and appropriate antibiotic treatment seems the best policy in treating this group of patients. However, adequate treatment is not easy because many factors can interfere with an early and rapid identification of Chlamydia infection, including complicated mixed microflora of the vagina and cervix, a nonuser-friendly detection system, and the time required for identification, even with the combination of specific complaints and a high level of clinical alertness. When dealing with a female patient in a point-of-care (POC) clinic, we need to find the best strategy to provide the most efficient way to detect this infection. MATERIALS AND METHODS: Totally five traditional methods and advanced technologies used for the diagnosis of Chlamydia infection in women were reviewed. A criterion proposed by World Health Organization with an acronym of ASSURED, representing affordable price, high sensitivity, high specificity, user-friendly design, rapid process, minimal equipment, and delivered-or-not, was used to reexamine these tools if they are the best tools. A multiplexed microchip-based immunoassay was evaluated as a potential tool. The ASSURED score was compared and a Chi-square test with a p value less than 0.05 was considered significant. RESULTS: Traditional methods, such as symptoms approach, microscopic examination, and microorganism culture that have been broadly used once, are affordable, simple, and equipment-free but their relatively low sensitivity and specificity limit their use as a test of POC setting for these infected women. On the other hand, advanced technologies, such as antigen detection by immunoassay and nucleic acid amplification tests, have contributed to major progress in the diagnosis of Chlamydia because of its accuracy, convenience, and time saving. However, nucleic acid amplification tests are too expensive, so they cannot be accepted as a screening tool in a developing country. The only significant finding with p value less than 0.01 was achieved when a more sensitive immunoassay system developed successfully as a test of POC setting. CONCLUSIONS: Eventually, advances in laboratory techniques will satisfy our needs to detect Chlamydia infection economically and instantly. Microarray chips might be a relatively rapid, easy, inexpensive, and sensitive tool to detect many pathogens, including Chlamydia, using a one-time vaginal sampling process, which might make a POC policy possible.