Personal and agricultural antibiotic use increasing resistant E.
coli in Peruvian children
10 May 2010
Direct and indirect exposure of young children to antibiotics
through medical and agricultural usage can increase their risk for
carriage of antibiotic resistant E. coli, according to a new
study published in the May issue of the American Journal of Tropical
Medicine and Hygiene.
Antimicrobial resistance has emerged as a global health problem and
is a major impediment in managing childhood infectious diseases.
It is estimated that E. coli causes disease in hundreds
of thousands of people around the world each year. E. coli
can be transmitted from animals and humans through several sources,
the most common being contaminated food and water. While most E.
coli are harmless, and are carried as a normal part of the
human intestinal flora, such commensal bacteria might serve as an
important reservoir of resistance that can be transmitted to
disease-causing E. coli and other bacterial species.
The study, conducted by the Johns Hopkins Bloomberg School of
Public Health, revealed several factors affecting
antibiotic-resistant E. coli carriage in young children in
Peru. By analyzing E. coli samples from more than 500
children, the researchers were able to identify individual,
household, and community factors influencing carriage of the
"This study is unique in having evaluated a number of risk
factors at multiple levels in very young children for carrying
antibiotic-resistant E. coli bacteria. By examining all
these factors, we were able to reach a more comprehensive
understanding of how resistant E. coli is transmitted in
the developing world," said lead study investigator Dr. Henry D.
Kalter, Associate, Department of International Health, Johns Hopkins
Bloomberg School of Public Health.
"In analyzing the study results, we learned that children's use
of antibiotics, as well as their family members' use, increased
their risk for carrying resistant E. coli, and that
residing in an area where a greater proportion of households served
home-raised chickens protected against resistance.
"This protective effect can be understood in light of the fact
that the home-raised chickens carried significantly lower levels of
resistant E. coli than did the market chickens, which in
Peru are intensively raised with antibiotics. The strength of this
community level variable suggests that this is where the
transmission of resistance resulting from agricultural antibiotics
use was taking place."
In poor communities in developing countries (such as Peru), with
inadequate protection of excreta and water, contamination of the
environment with antibiotic-resistant bacteria appeared to play at
least as great a role in children's carriage of resistant E.
coli as did the children's own antibiotics use.
"This study is important in a number of respects," said Edward T.
Ryan, M.D., President, American Society of Tropical Medicine and
Hygiene (ASTMH). "It improves our understanding of the growing
global public health threat of antibiotic-resistant organisms, and
underscores the critical role that antibiotic use in animals plays
in contributing to this threat. The vast majority of the tons and
tons of antibiotics ingested each year on this planet are
administered to livestock and animals. This study clearly shows that
such use comes with a very real cost to human health."