Children rehydrated with three different carbohydrates | Medicinal plants damage membranes of Vibrio cholerae. | Bangladeshi scientist discovers cause of cholera | Niger: Dozens killed by cholera
Campbell, Dan
Children with cholera rehydrated with three different carbohydrates
Eur J Clin Nutr. 2010 Oct;64(10):1116-24.
Short-chain fatty acids and commensal microbiota in the faeces of severely malnourished children with cholera rehydrated with three different carbohydrates.
Monira S, Hoq MM, Chowdhury AK, Suau A, Magne F, Endtz H, Alam M, Rahman M, Pochart P, Desjeux JF, Alam NH.
International Centre for Diarrhoeal Disease Research Bangladesh, Dhaka, Bangladesh. smo...@icddrb.org
BACKGROUND:
Short-chain fatty acids (SCFAs) liberated by fermentation of complex
carbohydrates might stimulate water and salt absorption, and provide energy. The
aim of the study was to assess the number and proportion of faecal bacteria and
the concentration of SCFAs of severely malnourished children with cholera
receiving
oral rehydration solution (ORS) containing glucose, amylase-resistant starch
(ARS) or rice.
METHODS: Serial faecal samples were collected from 30 malnourished children with cholera until rehydration and partial nutritional recovery. SCFAs were identified and quantitated by high-performance liquid chromatography. In situ hybridization combined with flow cytometry was used to analyse the microbiota in the faeces.
RESULTS: Before treatment the concentration of total SCFA in faecal sample of cholera children was found to be 4.7±0.6 mmol/kg and it increased steadily until 95.0±8.7 mmol/kg at day 28. Among different ORS groups, concentration was significantly higher in the Rice-ORS group at day 1 (P<0.011) and at day 2 (P<0.025). During recovery faecal output was significantly reduced and the number of bacteria also increased faster in the Rice-ORS group than in the glucose-ORS group at day 1 and day 2 (P<0.01), and a modest increase in bacterial number was observed in the glucose-ORS plus ARS group (day 1, P=0.07; day 2, P=0.09).
CONCLUSION: Clinical recovery was associated with an increase in bacterial and SCFA concentrations with all three carbohydrates in ORS. However, the increases were significantly higher in children receiving Rice-ORS.
Medicinal plants damage membranes of Vibrio cholerae.
Appl Environ Microbiol. 2010 Oct;76(20):6888-94.
Extracts of edible and medicinal plants damage membranes of Vibrio cholerae.
Sánchez E, García S, Heredia N. Departamento de Microbiología e Inmunología, Universidad Autónoma de Nuevo León, Apdo. Postal 124-F, Ciudad Universitaria, San Nicolás de los Garza N.L. 66451, México.
The use of natural compounds from plants can provide an alternative approach against food-borne pathogens. The mechanisms of action of most plant extracts with antimicrobial activity have been poorly studied. In this work, changes in membrane integrity, membrane potential, internal pH (pH(in)), and ATP synthesis were measured in Vibrio cholerae cells after exposure to extracts of edible and medicinal plants. A preliminary screen of methanolic, ethanolic, and aqueous extracts of medicinal and edible plants was performed. Minimal bactericidal concentrations (MBCs) were measured for extracts showing high antimicrobial activity. Our results indicate that methanolic extracts of basil (Ocimum basilicum L.), nopal cactus (Opuntia ficus-indica var. Villanueva L.), sweet acacia (Acacia farnesiana L.), and white sagebrush (Artemisia ludoviciana Nutt.) are the most active against V. cholera, with MBCs ranging from 0.5 to 3.0 mg/ml.
Using four fluorogenic techniques, we studied the membrane integrity of V. cholerae cells after exposure to these four extracts. Extracts from these plants were able to disrupt the cell membranes of V. cholerae cells, causing increased membrane permeability, a clear decrease in cytoplasmic pH, cell membrane hyperpolarization, and a decrease in cellular ATP concentration in all strains tested. These four plant extracts could be studied as future alternatives to control V. cholerae contamination in foods and the diseases associated with this microorganism.
Written by envhealth@usaid Edit
October 14, 2010 at 2:18 pm
Posted in Cholera
Tagged with medicinal plants
Satellite phage TLCφ enables toxigenic conversion
Nature advance online publication 13 October 2010 | doi:10.1038/nature09469
Satellite phage TLCφ enables toxigenic conversion by CTX phage through dif site alteration
Faizule Hassan1, M. Kamruzzaman1, John J. Mekalanos2 & Shah M. Faruque1
Molecular Genetics Laboratory, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka-1212, Bangladesh; Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, Massachusetts 02115, USA
Correspondence to: Shah M. Faruque1 Email: far...@icddrb.org
Bacterial chromosomes often carry integrated genetic elements (for example plasmids, transposons, prophages and islands) whose precise function and contribution to the evolutionary fitness of the host bacterium are unknown. The CTXφ prophage, which encodes cholera toxin in Vibrio cholerae1, is known to be adjacent to a chromosomally integrated element of unknown function termed the toxin-linked cryptic (TLC)2.
Here we report the characterization of a TLC-related element that corresponds to the genome of a satellite filamentous phage (TLC-Knφ1), which uses the morphogenesis genes of another filamentous phage (fs2φ) to form infectious TLC-Knφ1 phage particles. The TLC-Knφ1 phage genome carries a sequence similar to the dif recombination sequence, which functions in chromosome dimer resolution using XerC and XerD recombinases3. The dif sequence is also exploited by lysogenic filamentous phages (for example CTXφ) for chromosomal integration of their genomes.
Bacterial cells defective in the dimer resolution often show an aberrant filamentous cell morphology3, 4. We found that acquisition and chromosomal integration of the TLC-Knφ1 genome restored a perfect dif site and normal morphology to V. cholerae wild-type and mutant strains with dif− filamentation phenotypes. Furthermore, lysogeny of a dif− non-toxigenic V. cholerae with TLC-Knφ1 promoted its subsequent toxigenic conversion through integration of CTXφ into the restored dif site.
These results reveal a remarkable level of cooperative interactions between multiple filamentous phages in the emergence of the bacterial pathogen that causes cholera.
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature09469.html
Bangladeshi scientist discovers cause of cholera
A Bangladeshi scientist has discovered how a harmless bacteria causes severe form of diarrhoea known as cholera.
Dr Shah M Faruque, head of Molecular Genetics at International Centre for Diarrhoeal Diseases Research, Bangladesh (ICDDR,B), and his research team have discovered the findings.
This important breakthrough will have far reaching implications globally in predicting when new types of cholera-causing bacteria, called Vibrio cholerae will next appear and start infecting people and causing them to fall ill, according to the research team.
The findings published in Nature, the internationally acclaimed science journal that publishes outstanding discoveries, were the work of Dr Faruque and his Dhaka-based research team, in collaboration with Dr John Mekalanos of Harvard Medical School in Boston, USA.
The new research explains how bacteria become infected with their own viruses and how these viruses interact to allow the bacteria to produce substances that interact with the intestinal cells to make them produce the large quantities water and electrolytes known as diarrhoea, said Dr Alejandro Cravioto, executive director of the ICDDR,B.
Although some of these mechanisms are already known, the work of Dr Faruque and his associates advances the understanding of how these different viruses interact to make the bacteria a more effective pathogen.
The new phase identified, called the `TLC phase` adds a new piece to the puzzle on how the bacteria get information they need from the environment to use it to live in difficult environments like the human intestine.
“We discovered and characterized the `TLC phase` which changes, albeit slightly, the chromosomal sequences of the cholera bacterium,” Dr Faruque said.
This subtle change enables an incoming toxigenic CTX phase genome to be incorporated and in doing so a harmless strain of V Cholera is transformed into a dangerous killer, he said.
The World Health Organization (WHO) estimates that cholera kills more than 100,000 people every year, and infects more than a million.
Recent epidemics in sub-Saharan African countries like Zimbabwe and Mozambique and more recently in the flooded areas of Pakistan highlight the continuing threat of cholera and need for studies like ICDDR,B for a better understanding of the disease and its capacity to transmit in the environment, he said.
“We hope that our knowledge will help save lives and have far reaching implication in public health research,” Dr Faruque said.
http://www.thedailystar.net/newDesign/latest_news.php?nid=26422
Written by envhealth@usaid Edit
October 14, 2010 at 1:31 pm
Posted in Cholera
Tagged with Bangladesh
Nigeria: Group Fights Cholera Through Purification of Water Sources
14 October 2010, Lafia — Greenwatch Initiative, an implementing partner in the Building Nigeria‘s Response to Climate Change (BNRCC), has introduced the purification of water sources with chemicals in Daudu and Falgore communities in Benue and Kano states respectively, to fight cholera.
A statement by the group’s executive director, Emmanuel Tembe, said the climate change group is promoting water purification, hygiene and sanitation practices in the rural communities as a preventive measure against cholera and other water borne diseases.
The statement said water purifying chemical obtained from Society for Family Health (SFH), is being used in the exercise. “Both men and women were targeted for the exercise but more emphasis was directed at the women because of their gender role in domestic activities.
“In Daudu community, the demonstration of water purification using the PUR chemical was done with 210 women in attendance in two places.
Each woman in attendance was given a row of the PUR chemical which contains 12 sachets, 3 cartoons of the chemical containing 20 rows (240 sachets) were given to the Project Implementation Committee (PIC) to be sold at a revolving cost of N10.00 per sachet,” the statement said further.
It added that the same demonstration of water purification using PUR was done in Falgore community with 86 women and 95 men. Each of them collected one row of the PUR chemical with a commitment to purify all sources of water before drinking to prevent the diseases.
UN says nearly 1,900 killed in serious cholera outbreak in 4 West African nations
By The Associated Press (CP) – Oct 11, 2010
GENEVA — The U.N. says a serious outbreak of cholera is gripping West Africa. A spokeswoman for the U.N. Office for the Coordination of Humanitarian Affairs says a cholera epidemic that has hit Nigeria, Chad,Cameroon and Niger could spread to neighbouring countries.
The World Health Organization says 1,879 deaths have been reported in the four countries as of Oct. 3. That was from nearly 40,500 cases.
The wave of cholera started a few months ago. The U.N. says flooding in the region, as well as poor hygiene conditions and populations movements, have contributed to the “unusually high incidence of cholera.”
Nigeria has experienced the highest number of deaths, nearly 1,200, in its worst cholera outbreak in two decades.
Niger: Dozens killed by cholera
Oct 13, 2010, Niamey, Niger – An outbreak of cholera has killed at least 67 people in Niger, the country’s Public Health minister, Nouhou Hassan, said in Niamey on Tuesday. He told reporters that some 1,061 cases have been recorded so far, adding that the situation was, however, under control, thanks to the efforts of various agents on the ground with support from the authorities.
The minister said Diffa region had recorded 442 cases, Maradi (426 cases), Zinder (191 cases) and Tahoua (2 cases).
Dan Campbell, Web
Manager
Environmental Health at USAID
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