Thursday, June 30, 2011

Researcher’s data suggest a Chlamydia pneumoniae – asthma link

The chronic respiratory illness, asthma, which affects hundreds of millions of people throughout the globe, may be linked to a respiratory bacterium.
This is according to a report in the magazine, Drug Discovery and Development, who reported Tuesday on research presented Monday at this weeks American Society for Microbiology General Meeting.
According to Eduard Drizik of the University of Massachusetts, Amherst, there is a subset of severe asthmatics that have Chlamydia pneumoniae in their lungs which results in antibody production and a worsening of the asthma.
The study set out to determine if the presence of Chlamydia-specific antibodies could predict asthma severity and antibiotic treatment alleviate the asthma in these patients.
Drizik goes on to explain the link: "The data revealed a statistically significant link between Chlamydia-specific IgE antibody production and the severity of asthma.Of the asthma patients analyzed, 55% had Chlamydia-specific IgE antibodies in their lungs compared to 12% of blood donor controls."

And patients who were treated for the bacterial infection with antibiotics saw major improvements in the severity of their asthma, and in some of the patients, asthma symptoms were eliminated.
Formerly known as the TWAR agent (Taiwan Acute Respiratory Agent), Chlamydia pneumoniae or as it’s more recently known as Chlamydophila pneumoniae is a bacteria which causes pneumonia or bronchitis.Less common presentations are pharyngitis, laryngitis, and sinusitis. The spectrum of illness can range from asymptomatic infection to severe disease.

Tuesday, June 28, 2011

IDSA issues policy paper to fight “superbugs”

The Infectious Diseases Society of America (IDSA) issued a multi-faceted plan to fight antibiotic resistance and the creation of “superbugs” on Thursday, Apr.7, which was also World Health Day 2011.
In a press release issued the same day, it states a doomsday scenario of sorts:
Infections are becoming increasingly resistant to existing antibiotics, while the number of new antibiotics being developed has plummeted.  IDSA warns that unless sweeping actions are taken now, the future could resemble the days before these miracle drugs were developed. People will die of common infections and many medical interventions we take for granted – surgery, chemotherapy, organ transplantation, and premature infant care – will no longer be possible.
According to IDSA President James M. Hughes, MD, FIDSA, “The way we’ve managed our antibiotics for the past 70 years has failed. Antibiotics are a precious resource, like energy, and we have a moral obligation to ensure they are 
available for future generations.”
Hughes goes on to say, “IDSA has a comprehensive, multifaceted plan to address this crisis, but time is running out. If such measures are not implemented now by Congress, federal agencies and health care providers across the country an increasing number of lives will be devastated and lost.”
Whether it’s MRSA, Acinetobacter baumanii or now Klebsiella pneumoniae, the incidence has risen dramatically.
 IDSA's new policy paper, published in the journal, Clinical Infectious Diseases is titled "Combating Antimicrobial Resistance: Policy Recommendations to Save Lives"Here the IDSA makes the following recommendations:
Creating incentives and removing economic and regulatory disincentives for antibiotic research and development so companies find developing new antibiotics a viable business endeavor. 
•    Recalibrating and better communicating the FDA's requirements for new antibiotic approvals.  
•    Funding antibiotic R&D efforts under the Department of Health and Human Services' Biomedical Advanced Research and Development Authority and proposed independent strategic investment firm.   
•    Supporting R&D for rapid diagnostic tests to identify the cause of infections more quickly.  
•    Designating a leader within HHS to facilitate coordination of federal efforts and better utilize outside experts.  
•    Promoting the judicious use of available antibiotics through better stewardship programs and infection control practices.   
•    Creating an Antimicrobial Innovation and Conservation Fee to help pay for drug development and stewardship.   
•    Strengthening public health measures and research that lead to new interventions.  
•    Establishing non-profit public-private partnerships to invest in bringing new antibiotics to market.

UK study: Component of mucus protective against roundworm infections

The presence or absence of a specific mucin could be the reason a person is infected with an intestinal roundworm or not according to research published in the Journal of Experimental Medicine and  press release on Thursday.
The researchers from the University of Manchester, UK have identified a key component of mucus found in the guts of humans and animals that is toxic to worms.
This component, Muc5ac, is a mucin which is rarely found in the mucus of the gut that is toxic to the nematode and is key to the expulsion of the parasites from the gut.
In the study, researchers used a mouse model infected with the parasite Trichuris muris, which is closely related to the human equivalent, the whipworm, Trichuris trichiura.
According to researcher, Dr. David Thornton, “We previously found that mice that were able to expel this whipworm from the gut made more mucus. Importantly, the mucus from these mice contained the mucin, Muc5ac. This mucin is rarely present in the gut, but when it is, it alters the physical properties of the mucus gel.”

They also discovered that mice genetically incapable of producing Muc5ac were unable to expel the worms, despite having a strong immune response against these parasites. This resulted in long-term infections.
They found that Muc5ac is also essential for the efficient expulsion of other intestinal parasites that infect humans like hookworm and threadworm.
Dr Sumaira Hasnain, lead scientist on the project said, “For the first time, we have discovered that a single component of the mucus barrier, the Muc5ac mucin, is essential for worm expulsion. Our research may help to identify who is and who isn’t susceptible to parasitic worms, and it may eventually lead to new treatments for people with chronic worm infections.”

Monday, June 27, 2011

Paper: Case of NDM-1 transmission in Canada without foreign travel

A case of person-to-person transmission of a bacterium with the NDM-1 enzyme in Canada has been described in an article in Monday’s issue of the Canadian Medical Association Journal.
The paper talks of an 86-year-old man from Ontario who suffered a stroke and was admitted to the hospital. While performing a urine culture on the elderly gentleman, doctors discovered he had a gram-negative bacterium that expressed the NDM-1 enzyme.
A couple of things interesting about this case; first, the man has not left the province in over ten years and none of his family or friends have traveled to India, and the organism isolated from his urine was not the usual suspects, E.coli or Klebsiella pneumoniae, instead it was  Morganella morganii a common cause of UTIs.

Until this case, all cases of infection with bacteria expressing this enzyme in Canada were from patients with a history of travel to India, Pakistan or Bangladesh.
Though Canadian medical experts say this is not a cause for concern, they do want to recognize that patients who express this enzyme don’t necessarily have to have a history of travel to one of the above countries, and to ensure physicians and laboratories are aware of the possibility of this occurring in a Canadian where the organism is locally acquired.
NDM-1 (New Delhi metallo-β-lactamase 1) is an enzyme that is carried in certain gram negative bacteria like E. coli and Klebsiella, and makes the bacterium resistant to the beta lactam antibiotics, including carbapenems, with the exception of the monobactam agent, aztreonam. 

Saturday, June 25, 2011

New research finds bedbugs are carriers of antibiotic-resistant bacteria

The resurgence of bedbug infestations have been a nuisance at best for hotels and homeowners as scientists have always said that the tiny blood-sucking creatures didn’t carry infectious agents that could harm humans.
However, new research out of Canada reported Wednesday sheds some different light of the issue of bedbugs as a vector of disease.
In the latest issue of Emerging Infectious Diseases , Christopher F. Lowe, of the University of Toronto in Ontario, Canada  and Marc G. Romney, of  St. Paul’s Hospital, Providence Health Care in Vancouver, British Columbia, Canada, say that the previously thought nuisance insects may actually be able to transmit drug-resistant bacteria.
What they found were some of bedbugs collected tested positive for Vancomycin-resistant Enterococcus faecium (VRE) and Methicillin-resistant Staphylococcus aureus (MRSA), two very important antibiotic-resistant bacterium.
The patients in the study come from low-income urban areas of Vancouver where bedbug infestations are increasing.
Lowe and Romney conclude:
"Bedbugs carrying MRSA and/or VRE may have the potential to act as vectors for transmission. Further studies are needed to characterize the association between S. aureus and bedbugs. Bedbug carriage of MRSA, and the portal of entry provided through feeding, suggests a plausible potential mechanism for passive transmission of bacteria during a blood meal. Because of the insect’s ability to compromise the skin integrity of its host, and the propensity for S. aureus to invade damaged skin, bedbugs may serve to amplify MRSA infections in impoverished urban communities."

This is the first findings linking bedbugs to infectious organisms and the researchers point out that the findings from the study are by no means conclusive.
Bedbugs are tiny parasitic insects, which feed on the blood of warm-blooded mammals. Typical adverse health effects from bedbug bites include skin rashes, allergic reactions and psychological effects.
In the United States, the bedbug was essentially eradicated since the 1940s but found resurgence at the end of the century. Though pesticides have historically been effective against bedbugs, resistance to many pesticides have developed. In addition to pesticides, non-pesticide methods have been used such as vacuuming and heat-treating.

Plasmodium knowlesi: The fifth human malaria?

In a paper published Thursday in the journal PloS Pathogens, researchers from Malaysia and London warn that that this species of malaria, most frequently seen in macaques could eventually target humans.
Although Plasmodium knowlesi, often considered the fifth human malaria species (along with P. falciparum, P. vivax, P. malariae and P. ovale) as it has been seen in humans, it is still mostly known as a malaria of macaques in southeast Asia where 78% of the monkeys tested were positive.
However, Professor Balbir Singh and colleagues are concerned about this huge reservoir of P. knowlesi in the monkeys and the increasing human populations and deforestation, the disease could shift to humans.
Professor Singh asks the important question, "We don't know how mosquito behavior will change”.
Singh goes on to say, “it is easy to see how this species of malaria could switch to humans as the preferred host. This would also hamper current efforts aimed at eliminating malaria.”
Dr. Hilary Ranson, from the Liverpool School of Tropical Medicine told the BBC:
"Deforestation or any perturbation of the ecosystem frequently leads to humans being exposed to an expanded range of biting insects and the pathogens they transmit, yellow fever is a good example of this."

"To me the important message is that disruption of the environment exposes people to a range of known and potentially unknown pathogens transmitted by blood feeding insects that do not typically feed on humans" 
Plasmodium knowlesi is mostly found is mostly found in South East Asian countries particularly in Borneo, Malaysia, Myanmar, the Philippines, Singapore, and Thailand. 
Plasmodium knowlesi is absent in Africa. This may be because there are no long-tailed and pig-tailed macaques (the reservoir hosts of P. knowlesi) in Africa and many West Africans lack the Duffy antigen - a protein on the surface of the red blood cell that the parasite to uses to invade.
Mosquitoes belonging to the Anopheles leucosphyrus group are known to transmit P. knowlesi from monkeys to humans.

Thursday, June 23, 2011

Manuka honey as a topical antibiotic

Researchers from the University of Wales Institute Cardiff said this week that honey from bees foraging on manuka trees in New Zealand have shown antimicrobial properties in in vitro lab experiments.
The study, according to Professor Rose Cooper, showed that this honey could be used as a “topical agent”, and when applied with antibiotics, it could be effective against certain “superbugs” that cause skin infections like MRSA.
According to Cooper, their initial findings show that medical grade manuka honey can stop bacteria from establishing themselves on tissue.
"Our findings with streptococci and pseudomonads [bacteria] suggest that manuka honey can hamper the attachment of bacteria to tissues which is an essential step in the initiation of acute infections. Inhibiting attachment also blocks the formation of biofilms, which can protect bacteria from antibiotics and allow them to cause persistent infections."

She added: "Other work in our lab has shown that honey can make MRSA more sensitive to antibiotics such as oxacillin - effectively reversing antibiotic resistance. This indicates that existing antibiotics may be more effective against drug-resistant infections if used in combination with manuka honey."
Of course, this initial work was done in a laboratory and clinical trials on patients would be required.
The findings were presented at the Society for General Microbiology.

Wednesday, June 22, 2011

Campylobacter-contaminated poultry top pathogen-food combo in UF study

With the passing of the Food Safety Modernization Act (FSMA) this past January, researchers at the Emerging Pathogens Institute (EPI) at the University of Florida looked at what pathogen-food combinations had the greatest public health and economic impact in a report published Thursday.
In the report, “Ranking the Risks: The 10 Pathogen-Food Combinations with the Greatest Burden on Public Health,” they compared the risks by the various pathogen-food combinations and developed a comparable set of estimates of disease burden for 14 leading pathogens across 12 food categories (168 pathogen-food combinations).
The researchers then ranked them according to the economic burden they place on society.
The report shows that 14 food pathogens cause $14.1 billion in cost of illness and 61,000 Quality Adjusted Life-Years (QALY), a measure of health-related quality of life. In fact, the top five food pathogens; Salmonella, Toxoplasma gondii, Campylobacter, Listeria monocytogenes and noroviruses alone account for $12.7 billion in cost of illness.
Ranking by food alone shows that poultry, followed by complex foods (non-meat dishes comprised of multiple ingredients where no specific contaminated ingredient could be identified), pork, produce and beef were implicated in the most disease burden.
The Top 10 pathogen-food combinations are responsible for $8 billion in cost of illness and 37,000 QALY hours lost.
The Top 10 pathogen-food combinations are:
  1. Campylobacter-poultry
  2. Toxoplasma-pork
  3. Listeria-Deli meats
  4. Salmonella-poultry
  5. Listeria-dairy products
  6. Salmonella-complex foods
  7. Norovirus- complex foods
  8. Salmonella- produce
  9. Toxoplasma-beef
  10. Salmonella-eggs
Researchers identified nine major findings in their study and offer recommended actions to reduce the risks of these foodborne illnesses.
According to the University of Florida EPI, the Food Safety Modernization Act broadly directs the FDA to adopt a more preventative, risk-based approach, but doesn’t spell out exactly how this should be done. The risk-based analysis in the report provides the agency with one tool it can use to prioritize limited resources in ways that best protect consumers.

Monday, June 20, 2011

Travel health: amebiasis


This parasitic cause of traveler’s diarrhea is found basically worldwide; however tends to be more common in the tropics and in areas with questionable sanitation and poor nutrition. Africa, Asia and Central and South America is where the majority of illness and deaths tend to occur.
According to the Centers for Disease Control and Prevention (CDC), travelers to developing countries are at low but definite risk for amebiasis.
Data on travelers returning from the developing world were collected from 30 specialized travel or tropical-medicine clinics on six continents. The rate of acute amebic diarrhea ranged from 1.5% in travelers returning from Southeast Asia to 3.6% in those returning from Central America.
In industrialized countries, risk groups include male homosexuals, travelers and recent immigrants, and institutionalized populations.
People mostly get infected with the parasite from ingestion of fecally contaminated food and water containing the amebic cysts. The cysts are pretty resistant to chlorine.
Transmission can also occur through oral-anal contact with a chronically ill or asymptomatic carrier.
Amebiasis is caused by the protozoan parasite Entamoeba histolytica. The parasite may act as a non-pathogenic commensal or can invade tissues and give rise to intestinal and organ disease (rare).
Most infections with E. histolytica are asymptomatic. Intestinal infection can however cause acute and fulminating dysentery which includes fever, chills, bloody and mucoid diarrhea (amebic dysentery).
If the amoeba becomes invasive it can get into the bloodstream and be carried to the liver (most common), lungs or the brain. In these organs they can create abcesses (see photo of E. histolytica in liver tissue).
The incubation period is typically 2-4 weeks but may be several months or more.
Amebiasis can be diagnosed, though with some difficulty, by finding the characteristic cyst or trophozoites microscopically in stool. It must be differentiated from similar non-pathogenic amoeba.
The nonpathogenic Entamoeba dispar, however, is morphologically identical to E. histolytica, and differentiation must be based on isoenzymatic or immunologic analysis. A good indicator of E. histolytica is if the amoeba demonstrates ingestion of red blood cells.
There are also antibody and antigen detection assays and molecular tests available.
There are several medications available for treating intestinal and extraintestinal amebiasis. See the Medical Letter for treatment options.
The CDC recommends the following to prevent infection while traveling:
• Drink only bottled or boiled (for 1 minute) water or carbonated (bubbly) drinks in cans or bottles. Do not drink fountain drinks or any drinks with ice cubes. Another way to make water safe is by filtering it through an "absolute 1 micron or less" filter and dissolving chlorine, chlorine dioxide, or iodine tablets in the filtered water. "Absolute 1 micron" filters can be found in camping/outdoor supply stores.
• Do not eat fresh fruit or vegetables that you did not peel yourself.
• Do not eat or drink milk, cheese, or dairy products that may not have been pasteurized.
• Do not eat or drink anything sold by street vendors.
• Avoid sexual practices that may lead to fecal-oral transmission.