Indian Journal of Medical Microbiology Medknow Publications on behalf of Indian Association of Medical Microbiology ISSN: 0255-0857 EISSN: 1998-3646 Vol. 26, Num. 3, 2008, pp. 291-292

Indian Journal of Medical Microbiology, Vol. 26, No. 3, July-September, 2008, pp. 291-292

Research Snippets

Research snippets from the medical world

Desikan P

Bhopal Memorial Hospital and Research Centre, Raisen Bypass Road, Bhopal - 462 038, Madhya Pradesh
Correspondence Address:Bhopal Memorial Hospital and Research Centre, Raisen Bypass Road, Bhopal - 462 038, Madhya Pradesh
prabhadesikan@yahoo.com

Code Number: mb08097

1. Pickles and preserves are not immune to contamination by yeasts. A Japanese group found that yeasts have evolved a fail-safe system of interlocking molecular mechanisms to measure and cope with changing salt and sugar levels in their environments ( The EMBO Journal 26, 3521-3533 (2007 ). These mechanisms use environmental sensors to trigger at least two independent signaling pathways, both of which activate cells to produce and retain glycerol. This allows yeasts to colonise habitats where the concentration of sugars/salt would normally suck out water from cells of microorganisms via osmosis.
2. Fat mice should consider flossing. A study on rodents indicates that obesity weakens the immune system′s ability to contend with bacteria causing gingivitis. (Science NOW, Daily News, 10 December 2007 ) Researchers wrapped a silk thread soaked in a solution containing Porphyromonas gingivalis around a tooth of each mouse to cause gum disease infection. Compared to lean animals, the obese mice experienced 40% more bone loss around the roots of their teeth within 10 days after infection and had higher levels of bacteria in their plaque. The finding may explain why obese people are more likely to develop bacterial gingivitis and suggests that they may be more vulnerable to other bacterial infections as well.
3. A major stumbling block in chlamydial screening programmes is the lack of a user-friendly diagnostic test with a rapid turnaround time. A new Chlamydia Rapid Test for use with vaginal swab specimens may help circumvent this problem. A performance evaluation study of this test found that it had a turnaround time of 30 minutes, which allows for immediate treatment and contact tracing, potentially reducing the risks of persistent infection and onward transmission. ( BMJ. 2007 Dec 8; 335 (7631):1190-4.) The test could provide a simple and reliable alternative to nucleic acid amplification tests in Chlamydia screening programmes.
4. Superinfection with HIV-1 occurs when an individual who is already infected with one strain of HIV-1 acquires a second strain from a different partner. Because a reinfection event suggests that the immune response generated against the original infection is not sufficient to protect against later exposures, there are obvious implications for HIV-1 vaccine design. However, despite the potential importance of superinfection in HIV disease and vaccine development, there is uncertainty regarding its incidence and timing. Now, an in-depth, population-level assessment of HIV-1 superinfection ( PLoS Pathog. 3, e177;2007) confirms that natural HIV-1 infection does not always elicit a protective immune response, and that this lack of protection is largely independent of the timing of reexposure and the relatedness of the virus strains.
5. Antibiotic-resistant UTI is a nightmare at best. With the paucity of available antibiotics for treatment of such patients, prevention may be better than cure. A systematic review of randomised controlled trials (RCT) and quasi-RCTs of methenamine hippurate used for the prevention of UTIs in all population groups ( Cochrane Database Syst Rev. 2007 Oct 17;(4):CD003265) concluded that methenamine hippurate may be effective for preventing UTI in patients without renal tract abnormalities, particularly when used for short-term prophylaxis. In the light of these findings, disc diffusion tests for methenamine hippurate may soon need to be standardised.
6. Biosafety is an important, but often underemphasised, aspect of microbiology laboratory services. The ASM Public and Scientific Affairs Board submitted a letter on the 3 ^rd of October, 2007, to the Energy and Commerce Committee - Subcommittee on Oversight and Investigations hearing to examine the risks associated with biosafety level 3 and 4 (BSL3 and BSL4) laboratories. The ASM commented on several points related to the topic of the hearing, including the importance of biocontainment laboratories in light of the rise of new and old infectious diseases with high morbidity and mortality over the past 30 years, as well as the potential for use of microbes for bioterrorism; the importance of biosafety requirements for microbiology laboratories and personnel; and recommendations to improve biosafety training, oversight, resources, reporting, and biosecurity. The entire statement can be found on the ASM website at http://www.asm.org/Policy/index.asp/bid=53313 .
7. As far as infectious diseases go, any clinical presentation is possible. A report of actinomycotic infection causing spastic paraparesis (Spinal Cord (2007) 45, 787-789) only underlines this. A 30-year-old male had multiple discharging sinuses on the nape of the neck and upper back for 7 years which resulted in cervical cord compression and spastic paraperesis. A diagnosis of actinomycosis was made on culture of tissue from the site of the discharging sinuses. The patient responded to medical therapy with penicillin.
8. Innate antiviral immunity is alive and kicking. Evidence for this has been provided by a study ( Nature Reviews Immunology 7, 918-919;2007) which shows that, in mammals, type I interferons (IFNα and IFNβ) upregulate several cellular miRNAs that can inhibit the replication of, or infection by, hepatitis C virus.
9. There is still a long way to go in the development of a rapid test for definite laboratory diagnosis of extrapulmonary tuberculosis. A study examined the interferon gamma-producing T-cell responses to early secreted antigenic target 6 and culture filtrate protein 10 by enzyme-linked immunospot (ELISPOT) assay in patients diagnosed as having extrapulmonary tuberculosis based on clinical and laboratory findings (Arch Intern Med. 2007 Nov 12;167(20):2255-9). The sensitivity and specificity of the ELISPOT assay were 94% (95% CI: 79 to 99%) and 88% (95% CI: 72 to 97%), respectively.
10. Although adults can develop clinical immunity to malaria, women who are pregnant for the first time are susceptible to infection with variants of Plasmodium falciparum that sequester in the placenta. A report ( Infect. Immun. 75, 4838-4850; 2007) now shows that the P falciparum that causes pregnancy-associated malaria preferentially transcribes six genes. This could be an important finding for development of new vaccines for malaria.