A new report from the American Association of Pediatrics (1) is emphasizing that children are especially at risk from antibiotic resistant bacteria such as salmonella, enterococci and campylobacter. The report is very critical of the use of antibiotics in animal agriculture, especially as growth promotion in healthy animals for food production. This is called "nontherapeutic use". Evidence now exists that the use of antimicrobial agents in food-producing animals have a direct negative impact on human health. For example, VRE (Vancomycin-resistant enterococci) has increasingly affected children, making them seriously ill. VRE has been found in chickens imported to Japan. (2)

A disease that used to be easy to treat with penicillin is Streptococcus pneumoniae, which cause ear infections. Now, many children suffer from pneumonia that is resistant to penicillin: 45 % of all S. pneumonia strains are not reacting to such important antibiotics. Yet, penicillin such as beta-lactam drugs are commonly used for all types of animals as growth promoters.

Fig. 1: Use of antibiotics is on the rise in Japan: Human use of antibiotics in Japan has increased from 517 in 2000 to 520 ton in 2003. About three times as much is estimated to be used in Japanese agriculture for farm animals. The use for farmed animals (both therapeutic and non-therapeutic) is also rising at an alarming rate. 3)

Japan Offspring Fund also finds it worrying that many baby products contain antimicrobial agents. Even toys and clothes sometimes contain such substances. However, studies show that some kinds of E. Coli are beginning to show resistance to triclosan, an active ingredient in such soaps, toothpastes and other antiseptic products.

Campylobacter

Children are at great risk of severe complications, if they become infected. The AAP report reveals that in the U.S., almost 20 % of all reported cases of Campylobacter infections occur in children younger than 10 years. For infants younger than 1 year, the incidence is twice that in the general population. In the U.S., the drug that is used for treating Campylobacter infections is erythromycin. It is also approved for use in food-producing animals both for therapeutic and growth-promotion purposes. Erythromycin belongs to the group called macrolides. Currently, about 5 % of Campylobacter are macrolide-resistant. For adults, there are other drugs, such as fluoroquinolones and tetracyclines, but for children they are too strong and often dangerous, thus not recommended. If resistance to macrolides increases, young children in particular will be at risk. Many macrolides are commonly used for all different food animals, in spite of the risks.

Fluoroquinolones such as Cipro are considered a very important class of drugs. However, 24 % of chicken bought in grocery stores were contaminated with Campylobacter resistant to Cipro. The U.S. FDA is trying to ban the use of fluoroquinolones, but the maker, Bayer, refuses to take it off the market. Instead, Bayer has sued FDA so that they can continue to sell Baytril (almost identical to Cipro but sold as animal drug) while the lawsuit drags on. It is interesting to note that Bayer in Japan is bragging about increased sales of this important drug.

According to WHO, bacteria resistant to one fluoroquinolone are generally cross-resistant to other fluoroquinolones. 4) This cross resistance includes fluoroquinolones used in animals and those available for human use. Fluoroquinolones (also known as Neoquinolones) are permitted both for chicken and cattle in Japan. In other countries, such drugs can be used for fish, a food that is very commonly consumed in Japan, also by small children.

Salmonella

More than one third of all illnesses from Salmonella occur in American children younger than 10 years old. Almost all cases are caused by food, according to Centers for Disease Control (CDC). Alarmingly, the incidence in infants is 10 times higher than in the general population. The AAP report notes that "the treatment of Salmonella infections, especially in young children, has become increasingly difficult because of antimicrobial resistance". In a 2001 study of American foods found that about 20 % of all ground meat (for hamburgers) is infected with Salmonella. 80 % of the Salmonella in that study were resistant to at least 1 antimicrobial agent, and 53 % were resistant to at least 3 antimicrobial agents.

Major sources of Salmonella infection are poultry, cattle, and pork. The problem is that so much antibiotics is used, especially for pork production. Also, studies show that more and more humans are getting sick from multi-resistant Salmonella. For example, the occurrence of Salmonella that is resistant to 8 or more antibiotics has increased from 0.1 % in 1996 to 0.3 % in 1999.

Conclusions

Foods are a major source of bacterial infections that threaten children in particular. The risks associated with antibiotic resistant bacteria is becoming a major health problem also in Japan. We urge food producers to stop using antibiotics for growth promotion. It is also necessary to limit the exposure to antibiotic residue in foods. Special attention must be paid to the foods that children may eat a lot of.

It is also a concern that very few toxicological studies have been able to study the effects on children or other special groups (such as elderly or people with weak immune systems). It is likely that many children are exposed to dangerous doses of drugs through food. Parents should seriously consider giving their children organic foods, produced without agricultural chemicals such as antibiotics.

Sources:

1) Shea, AAP 2004 http://pediatrics.aappublications.org/cgi/content/full/114/3/862
2) Ozawa, ASM 2002 http://aem.asm.org/cgi/content/full/68/12/6457
3) Data from Ministry of Health and Welfare, and Ministry of Agriculture (MAFF).
4) Use of quinolones in food animals and potential impact on human health. Report of a WHO meeting, June 1998. Geneva: WHO 1998.
http://www.who.int/emc-documents/zoonoses/docs/whoemczdi9810.html