* Approximately 70 percent of the 25 million pounds of antibiotics used in the United States each year is red to chickens, pigs, and cows for nontherapeutic reasons such as growth enhancement.
* This study evaluated whether animal feeds might serve as sources of antimicrobial-resistant bacteria on dairy farms.
* Antibiotics used on the farms participating in this study include
-- gentacin, and
* Ciprofloxacin is not used.
* Several studies have suggested an association between the use of antimicrobial agents in animal feeds and an increased risk that humans will be infected with resistant strains of bacteria.
* This study found a high frequency of ampicillin-resistant Enterobacteriaceae in animal feed, as well as resistance to streptomycin and tetracyclines.
* Because many bacteria isolated in this study are enteric microorganisms, fecal contamination of the feed ingredients seems likely.
* Such contamination may have occurred during the transport of feed ingredients to the storage bin.
* Also, the storage bins are not protected from animals that can carry Salmonella species and other enterics in their feces (e.g., dairy calves, rodents, birds).
* The presence of antimicrobial-resistant Enterobacteriaceae in dairy-cow feed ingredients raises serious questions about whether those microorganisms might enter the human food supply and infect people.
* In addition, the microorganisms may pose health risks to farmers and farm visitors.
A Norwalk-like Virus Outbreak on the Appalachian Trail
* An outbreak of gastrointestinal illness occurred among hikers on the Appalachian Trail in Virginia during May and June 1999.
* Almost 70 percent of hikers who consumed food or drank water at a convenience store in Catawba became ill.
* No illness occurred among those who bypassed the store or who ate only prepackaged food. No specific food items were implicated.
* The water supply for the taps inside the store was a hand-dug, shallow well.
* An ultraviolet light had been installed to purify the water and had been in operation for three years.
* Water samples from a sink in the food preparation area and from two outside hydrants were positive for total and fecal coliform bacteria.
* Water samples from a nearby post office and four nearby homes also were positive for total coliform bacteria.
* The authors identified Norwalk-like virus in hikers' stool and sera but not in the water sample taken from the store.
* The process of examining water and wastewater for enteric viruses is still considered experimental.
* Thus, the authors could not definitively implicate the water supply at the store as the point source of the outbreak.
* Because Norwalk-like viruses are highly infectious, it is often difficult to determine the source of transmission.
* The store may have provided the opportunity for the virus to spread very rapidly rather than have been the initial source of the outbreak.
* Long-distance trails usually have limited sanitation facilities and limited or contaminated water supplies.
* Traditional public-health methods of reducing the risk of infectious disease are difficult to apply in this setting.
* Water is not plentiful, so regular handwashing can be impossible.
* Most hikers in this study did not filter water while in town because they assumed the water was potable.
* Educating hikers on the nature of the Norwalk-like viruses may help control outbreaks.