Wednesday, February 13, 2013

Antibiotic Use Driving Resistance on Chinese Pig Farms

Here is a nice article from Time reporting on a recently released study by Zhu and colleagues that was reported in the Proceedings of the National Academy of Sciences (PNAS); this study looked at the presence of antibiotic resistance genes in the soil near 3 large Chinese pig farms.

These researchers found 149 different genes encoding antibiotic resistance, some of which were present at levels 192 to 28,000 times higher than control samples.

The Time article goes on to frame the problem of antibiotic use in the animal industry: 

1) In the United States, 4 times the amount of antibiotics that are used in humans are used for animals, many to treat otherwise healthy animals to promote growth

2) It is not clear to what extent this occurs (using antibiotics to promote animal growth-not expressly to treat sick animals)

3) Antibiotic resistance that develops in animals is a problem for humans-resistance genes can be carried in fertilizer, washed into rivers, et cetera. I previously touched on this in a blog about contaminated pork products and in another blog post about antibiotic use in cattle.  

See here for a link to an excellent perspective article on why antibiotic resistance matters, and what can be done to prevent entering a "post-antibiotic era." It has been well under 100 years since antibiotics were discovered and went into widespread use, and already we are seeing infections emerge that are completely resistant to all of the antibiotics in our arsenal. To a large extent this is due to the selective pressure of antibiotics on microorganisms. 

In order to secure a future in which we still have antibiotics to treat infections, we need to decrease antibiotic selective pressure on microorganisms wherever appropriate. This includes utilizing antibiotics judiciously in the animal growth industry; as mentioned in the Time article, we don't even know the scope of the problem. It is clear that we must act decisively, and concertedly, to address the problem of antibiotic resistance.  

Monday, February 11, 2013

Chagas Disease: A Major Issue in the Americas

The "kissing bug" that transmits
Chagas disease 
Here is a brief NPR piece on Chagas disease. Chagas disease is one of the neglected tropical diseases, and is an insect-borne parasitic infection that affects people in the Americas, especially parts of rural Latin America.

The insect vectors for the disease are known as "kissing bugs." They live in the walls and roofs of houses made of adobe, mud, straw and thatch, and emerge at night to feed on people's faces (I am not making this up). The insects thereafter defecate and the parasite (Trypanosoma cruzi), which is in the stool, gets inoculated through the skin when a person scratches.

Town of La Hicaca; this is one of the sites where we see
patients in Honduras; Chagas disease is a major problem in the area
It is estimated that 11 million people are currently living with this infection, and untreated these diseases persist for life. Chagas disease is associated with major morbidity: over time the infection can lead to heart failure and death from arrhythmias, as well as dilatation of the esophagus and colon with attendant gastrointestinal issues.

Where we practice in rural Honduras Chagas is a major issue. One of our projects for our upcoming May-June trip is administering a survey to assess people's risk for developing the infection, and their knowledge and understanding about how to prevent these infections.

Another nice article on Chagas from the New York Times can be found here.

Tuesday, February 5, 2013

Fecal Transplantation for Clostridium difficile Infections

Here is a nice interview a local TV station did with my friend and colleague Dr. Michael Edmond about using fecal transplantation to treat Clostridium difficile infections.

Clostridium difficile ('c dif') are bacteria that can cause diarrheal disease; a major risk factor for developing infections with these bacteria is previous antibiotic exposure. In the presence of antibiotics, these bacteria have the opportunity to outcompete the gut's normal bacteria, take over, and cause disease. These infections are associated with significant morbidity, and can be deadly, as well.

Although antibiotics can be used to combat these infections, some people suffer from recurrent infections despite antibiotic treatment. Fecal transplantation replaces the normal bacteria that are lost, and has been associated with high cure rates for patients who have failed other therapies.

The above video is well worth taking a look at.