Tips from the journals of the American Society for Microbiology

February 21, 2006

New Oral Vaccine May Protect against Pseudomonas aeruginosa in Humans

A new oral vaccine against Pseudomonas aeruginosa, a bacterium commonly known for afflicting patients with lung dysfunction, has shown to protect healthy human volunteers from infection say researchers from England and Australia. Their findings appear in the February 2006 issue of the journal Infection and Immunity.

Pseudomonas aeruginosa is a gram-negative bacterium particularly common in subjects with lung dysfunction, such as patients with cystic fibrosis (CF). Colonization can occur at an early age, but lack of clinical symptoms can allow the bacteria to fester resulting in chronic infection down the road. Current antibiotic therapies often fail to clear established infections, emphasizing the importance of a preventative vaccine.

In the study thirty healthy human volunteers received an oral dose of a whole-cell P. aeruginosa vaccine and reported for a follow-up examination fifty-six days after vaccination. Results showed several individuals as antibody responders against whole-cell P. aeruginosa while noting no vaccine-attributable adverse effects in any of the subjects.

"In our study, we have shown that the most significant and sustained responses to oral vaccination in human adult volunteers were serum IgA levels that pooled sera collected postimmunization have an increased capacity to promote opsonophagocytotic killing of P. aeruginosa," say the researchers. "We conclude that Pseudostat is safe and immunogenic in humans at this dose and that further studies to determine the appropriate dosage and efficacy are needed."

(A.W. Cripps, K. Peek, M. Dunkley, K. Vento, J.K. Marjason, M.E. McIntyre, P. Sizer, D. Croft, L. Sedlak-Weinstein. 2006. Safety and immunogenicity of an oral inactivated whole-cell Pseudomonas aeruginosa vaccine administered to healthy human subjects. Infection and Immunity, 74. 2: 968-974.)

New Norovirus Identified and Associated with Global Outbreaks

Researchers from Australia identified a novel strain of a gastrointestinal virus that may be responsible for outbreaks of gastroenteritis around the globe. They report their findings in the February 2006 issue of the Journal of Clinical Microbiology.

Norovirus (NoV) is the leading cause of gastroenteritis outbreaks in adults. Highly infectious, transmission commonly occurs through contaminated water and surfaces as well as person to person contact. Ease of transmission combined with low dosage required for infection results in extensive outbreaks in a variety of environments. In order to prevent further outbreak in an infected population, rapid and definitive diagnosis is imperative, reinforcing the need for effective testing and identification of the causative viral strain.

"The accurate diagnosis of viral gastroenteritis is essential in reducing its impact on society," say the researchers. "Each year in the United States, approximately 5,000 deaths are attributed to gastrointestinal disease of unknown etiology."

In a study marking NoV activity in Australia in 2004 researchers identified a novel genotype (GII.4) as the infective agent in eighteen outbreaks being investigated. Since its discovery, this new variant now referred to as Hunter virus, has been associated with large epidemics of gastroenteritis in The Netherlands, Japan and Taiwan.

"While the origin of the Hunter strain is unknown, we speculate that the Hunter strain, a predominant cause of NoV outbreaks in 2004 and 2005, could also continue to cause global epidemics in 2006 and beyond," say the researchers. "Identification of novel GII.4 variants may also lead to an increased ability to predict increases in NoV activity."

(R.A. Bull, E.T.V. Tu, C.J. McIver, W.D. Rawlinson, P.A. White. 2006. Emergence of a new norovirus genotype II.4 variant associated with global outbreaks of gastroenteritis. Journal of Clinical Microbiology, 44. 2: 327-333.)

First International World Health Organization Collaborative Study Examines HPV DNA Detection

Researchers report the results of the first World Health Organization international collaborative study of detection of human papillomavirus DNA in the February 2006 issue of the Journal of Clinical Microbiology.

Human papillomavirus (HPV) infection is the leading cause of cervical cancer in women. Of nearly 100 identified types of papillomaviruses, 70% of cancer cases are attributed to infection with HPV 16 and HPV 18. Current diagnostic methods such as cervical scrapes and genital biopsy specimens provide low numbers of HPV genomes and are often inconclusive in identifying the specific HPV strain, encouraging researchers to further examine universal detection methods using DNA.

This study was conducted by HPV experts and the World Health Organization, whose purpose is to establish international biological standard materials in therapy or diagnosis of human disease. Samples were collected from twenty-nine laboratories in twelve countries and results showed qualitative testing to be generally consistent in most laboratories. HPV 16 showed a detection rate of 62.5%, while HPV 18 reflected 73.9%. HPV 31 was the type least accurately detected and most invalid results were attributed to a lack of HPV test sensitivity.

"The results of this pilot study show that the majority of participating laboratories accurately detected HPV types at the highest concentrations represented in the panel," say the researchers. "Thus, the availability of international HPV DNA standards will contribute to the field of HPV prevention, diagnosis, and treatment."

(W.G.V. Quint, S.R. Pagliusi, N. Lelie, E.M. de Villiers, C.M. Wheeler, and the World Health Organization Human Papillomavirus DNA International Collaborative Study Group. 2006. Results of the first World Heath Organization international collaborative study of detection of human papillomavirus DNA. Journal of Clinical Microbiology, 44. 2: 571-579.)

American Society for Microbiology

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