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An unexpected find by a team of University of Georgia scientists suggests that reducing the use of antibiotics on poultry farms will do little, if anything to reduce rates of antibiotic resistant bacteria that have the potential to threaten human health.

Dr. Margie Lee, professor in the UGA College of Veterinary Medicine, and her colleagues have found that chickens raised on antibiotic-free farms and even those raised under pristine laboratory conditions have high levels of bacteria that are resistant to common antibiotics. Her findings, published in the March issue of the journal Applied and Environmental Microbiology, suggest that poultry come to the farm harboring resistant bacteria, possibly acquired as they were developing in their eggs.

“The resistances don’t necessarily come from antibiotic use in the birds that we eat,” Lee said, “so banning antibiotic use on the farm isn’t going to help. You have to put in some work before that.”

Lee and her team sampled droppings from more than 140,000 chickens under four different conditions: 1.) commercial flocks that had been given antibiotics; 2.) commercial flocks that had not been given antibiotics; 3.) flocks raised in a lab that had been given antibiotics; and 4.) flocks raised in a lab that had not been given antibiotics. The researchers examined levels of antibiotic resistance in normal intestinal bacteria that do not cause human illness and – in a companion study published in May in the same journal – also examined levels of drug resistant campylobacter bacteria, a common food-borne cause of diarrhea, cramping and abdominal pain.

They found that even chickens raised in the pristine laboratory conditions had levels of antibiotic resistance levels comparable to what was seen on farms that used antibiotics. Even when the levels were lower, Lee adds, they were still well above the reasonable comfort zone for antibiotic resistance – roughly five to 10 percent.

Seventy-three percent of the bacteria from one flock in the antibiotic-free commercial group were resistant to the drug oxytetracycline, for example, while 90 percent were resistant to the drug in a commercial flock that used antibiotics. Ninety-seven percent were resistant in the experimental flock that was given antibiotics, while forty-seven percent were resistant in the experimental group that was not given antibiotics.

Strikingly, they even found bacteria resistant to streptomycin, a common human antibiotic that is rarely used in poultry and was not used on the farms the researchers studied.

Bacteria swap genes relatively easily, and Lee explained that the concern is that drug resistance genes from bacteria that infect poultry could be passed on to bacteria that cause human illness. With these resistance genes, human bacterial illness could become harder to treat.

These concerns led the European Union to ban the use of antibiotics for growth promotion in chickens in 2006. In 2005, the U.S. Food and Drug Administration banned the use of the drug Baytril (the brand name for enrofloxacin, a fluoroquinolone antibiotic) in poultry, citing concerns that it could lead to resistance in human antibiotics such as Ciprofloxacin, also a fluoroquinolone.

Several advocacy groups are pushing for a more comprehensive animal antibiotic ban in the United States, but Lee said her research plus the evidence from the Baytril ban suggests that approach won’t help.

“They banned Baytril in 2005, and if you look at Baytril resistance in campylobacter now it’s essentially unchanged,” Lee said.

In previous studies, Lee has tried to recreate experimentally conditions that should lead to the swapping of resistance genes among bacteria. Lee said these events – known as the horizontal transfer of genes – do occur, but they may not be as common as initially thought.

What may be driving the antibiotic resistance that Lee has observed in her studies is what’s known as vertical transfer – from parent to child – of bacteria carrying resistance genes. In short, the birds may come to the farm harboring antibiotic resistant bacteria.

“This issue of antibiotic resistance is more complicated than once thought,” Lee said. “These findings suggest that banning antibiotics at the farm level may not be as effective as assumed. We need further studies to identify which management practice would be effective”

Lee stresses that for consumers, the advice on poultry is the same that it’s always been. Cook meat thoroughly and use proper food handling and preparation techniques – washing your hands regularly and keeping other foods away from raw chicken, for example – to minimize the risk of illness.

“All foods have the potential to contain pathogens – all of them,” Lee said. “There’s no substitute for good food handling and preparation.”

The study was funded by grants from the FDA and the United States Department of Agriculture.

The New Zealand Food Safety Authority’s (NZFSA) strategy to tackle New Zealand’s unacceptably high levels of human campylobacteriosis is progressing well with several areas of research and monitoring work already underway.

NZFSA has adopted a whole-of-food-chain approach to fighting the disease. All of the processes and procedures in place at each stage between rearing and eating poultry are under close scrutiny, with assistance from industry.

“We want to produce the greatest reductions in bacteria numbers as early as possible in the food chain (that is, as close to the farm as is practical and effective), and make further reductions at as many other points as practical and effective,” says Executive Director Andrew McKenzie.

“Working with the poultry industry, we have now established a data collection process that helps monitor the prevalence of Campylobacter in flocks and on carcasses.
“The data will help identify seasonal, geographic and demographic factors that may impact on flock prevalence; poor performing sheds and farms; opportunities for continuous improvement (i.e.: reduction) in flock prevalence and in the number of birds in a flock that may be infected.

“We are also working with Massey University and Mid Central Health to determine the actual (rather than suspected) source of human cases of infection to enhance surveillance. This work, centered in Manawatu, involves an intensive analysis of cases as soon as possible after diagnosis.

“The analysis will aid in-depth investigation of the precise circumstances that led to the cause of the food borne illness, such as cross-contamination or under-cooking.”

NZFSA is also working on:

Labelling is one of the key options being considered.

Our strategy is in line with what’s being done internationally to address Campylobacter in poultry. It is also pragmatic and recognizes that, because Campylobacter is a natural part of the gut bacteria of poultry it is unlikely to be completely eliminated. For this reason, consumer information will always be a key element of poultry food safety, just as it is with many other foods.

Industry-led trials of Campylobacter decontamination processes in a poultry processing premises have been delayed until later in the year because of a fire at the original site.

“We are now talking to various poultry companies to look at other intervention options being trialed and have called for data to be submitted for consideration,” says Dr McKenzie. “We are also seeking alternative ways of getting valid data should further delays eventuate.”

Campylobacter in Poultry Risk Management Strategy 2006-2009 can be downloaded here

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According to the NSW Food Authority and the Sydney South West Area Health Service (SSWAHS) Public Health Unit, there is an outbreak of gastroenteritis involving 98 people, many of whom ate food products from a Homebush hot bread shop over the weekend.

So far eighteen people have been hospitalized, and public health officers are currently interviewing all cases.

In the majority of cases interviewed so far, many reported having eaten either pork rolls or chicken rolls from the a Vietnamese bakery called the French Golden Hot Bread shop in Homebush West, opposite the Flemington train station. So far, thirteen cases have been confirmed as having salmonella infection. Incidentally, food poisoning involving Vietnamese Pork roll has occurred a few times in the past from other similar bakeries around the country.

SSWAHS Public Health Unit warns anyone who may have eaten these food products from the bread shop between Friday 23 March and Tuesday 27 March to be vigilant for the symptoms of salmonella infection and seek medical care.

Common symptoms of salmonella infection include diarrhea, abdominal pain, fever, nausea and vomiting. Symptoms usually last four to seven days.

The NSW Food Authority has advised that it sent inspectors into the bread shop to examine food safety practices and to sample foods for laboratory testing. It has placed a prohibition order on the bread shop restricting it from producing or selling the implicated foods. This basically shuts down the shop.

Dr Leena Gupta, SSWAHS Director of Public Health, recommends that anyone who contracts gastroenteritis should keep up their fluid intake, stay home and not return to work or school until 48 hours after symptoms have stopped.

People suffering symptoms should also not prepare food for others until at least 48 hours after they have completely recovered from the illness.

According to AM New York, the Japanese authorities in Tokyo has confirmed the country’s fourth outbreak of the virulent H5N1 strain of the bird flu virus at a poultry farm in Southern Japan.

About two dozen chickens were found dead at the farm in Shintomi, southwestern Miyazaki state, last month. The birds had been infected with the H5N1 strain deadly to humans, the Agricultural Ministry said.

The case marks Japan’s fourth H5N1 outbreak incident this year and the third to hit poultry farms in Miyazaki, Japan’s largest chicken-producing region.

Officials began slaughtering the approximately 93,000 chickens at the Shintomi farm earlier this week.

The farm also has been quarantined, and chicken ranchers within a six-mile radius are banned from transporting poultry or eggs out of the area while officials check that the infection has not spread.

The H5N1 virus has killed or prompted the slaughter of millions of birds across Asia since late 2003, and caused the deaths of at least 164 people worldwide, according to the World Health Organization.

Japan has confirmed only one human H5N1 infection and no human deaths.

Bird flu remains hard for humans to catch, but international experts fear it may mutate into a form that could spread easily between humans and potentially kill millions around the world.

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Eggs are a healthy and nutritious food, and should be a part of any regular diet. But the use of raw eggs in foods is always a risky proposition. Numerous investigations around the world where outbreaks in the use of raw eggs in foods have link them as a possible source of infection. In the majority of these outbreaks Salmonella isolated from clinical specimens matched Salmonella from food samples made with the raw eggs.

Some eggs carry low levels of pathogenic bacteria on their surface, such as Salmonella, which can multiply to harmful levels if left in an environment conducive to growth. Examples of such environments include raw egg based sauces (hollandaise, mayonnaise) and desserts (mousse, tiramisu). Only a few live cells of the salmonella bacterium can cause an infection.

In all these products raw eggs can be substituted for commercially produced sauces or pasteurized egg products that are free from harmful bacteria. This minimizes the risk of infection and the risk of getting a bad reputation if your businesses are involved!

According to recent findings, Campylobacteriosis has overtaken salmonellosis as the most reported animal infection transmitted to humans in the European Union.

The second annual European Food Safety Authority (EFSA) report highlights that while food safety measures have significantly reduced instances of salmonella affecting humans, more attention is needed to tackle campylobacter. The findings are likely influence future European food safety policy decisions makers with screening of campylobacter likely on foods.

The European Centre for Disease Prevention and Control (ECDC) provided the data on animal diseases that cross over to humans, known as zoonoses, and contributed to the analysis. The study was conducted on 24 European Union countries and Norway, Iceland and Switzerland.

European Union reporting of investigated cases of outbreaks caused by food contamination was made mandatory 2005 for the first time. During 2005, there were 5,311 food borne outbreaks reported in the European Union involving 47,251 people. They resulted in 5,330 hospitalizations and 24 deaths.

In 2005, reported cases of campylobacter in humans increased 7.8 per cent against the previous year rising to an incidence rate of 51.6 per 100,000 and a total of 197,363 recorded cases.

Salmonella, campylobacter, and viruses were the most important causes of reported food borne outbreaks in 2005. Egg and bakery products were the most common sources of Salmonella outbreaks, whereas broiler meat was an important source for both salmonella and campylobacter outbreaks. Food borne virus outbreaks were most often caused by drinking water, fruit and vegetables.

As in 2004, the primary source of campylobacter infections in 2005 was linked to fresh poultry with up to 66 per cent of some samples testing positive.

Salmonella infections, while still remaining a serious threat to human heath and very much in the public consciousness, fell by 9.5 per cent in 2005 to an incidence rate of 38.2 cases per 100,000, with a total 176,395 reported cases.

Reported salmonella was most often caused by fresh poultry and pig meat where proportions of positive samples up to 18 per cent were detected. In table eggs, findings of positive samples ranged from zero per cent to six per, but over the past five years an overall decreasing trend in occurrence of salmonella in eggs was observed. In animal populations, salmonella was most frequently detected in poultry flocks.

Relatively high proportions of campylobacter and salmonella isolates from animals and food were resistant to antimicrobials commonly used in treatment of human diseases. This is especially the case of resistance to fluoroquinolones in campylobacter isolates from poultry, where up to 94 per cent of isolates were reported resistant to ciprofloxacin.

This is a concern for the food industry and consumers as pathogen resistance compromises effective treatment and prevention.

The report provides additional information on other zoonotic diseases, which although not as prevalent in people as campylobacter and salmonella, still pose a threat to human health due to their severity.

EFSA highlights listeriosis, for example, in the report. The disease is relatively rare, with only 1439 reported cases in 2005, but has high case-fatality rate and potential affects on unborn children which can lead to miscarriage. Verotoxigencic Escherichia coli, a type of E coli, affected 3,314 people in 2005 and are another disease that can seriously damage the health of humans, especially children.

Ready-to-eat foods should be free of Salmonella as consumption of food containing this pathogen may result in food borne illness. The presence of this organism indicates poor food preparation and handling practices such as inadequate cooking or cross contamination.

Consideration may also be given to investigating the health status of food handlers on the premises who may have been suffering from salmonellosis or asymptomatic carriers of the organism.

Salmonella Parasites are animals, insects, viruses, and microscopic beings that latch onto, trap, trick, and live off of other living things. This series provides a colorful overview of what these yucky creatures are, how they work, what and why they do what they do. Salmonella bacteria lurk in raw eggs, chicken, and other common foods. If allowed to enter the human body, the bacteria multiply quickly and cause a variety of unpleasant diseases, some of which can result in death. In this book the life cycle and effects of this parasite are examined. Containment techniques are also discussed. Accelerated Reader: Reading Level 5.8, 0.5 Points.