Showing posts with label MRSA. Show all posts
Showing posts with label MRSA. Show all posts

Thursday, January 2, 2014

Food Safety is Not Assured-Antibiotic Resistant Bacteria found in 50 % of Chicken Breasts

data from Consumer Reports
About 48 million get sick, 128,000 are hospitalized, and 3,000 die each year from food borne diseases, according to 2007 data from the Centers for Disease Control and Prevention. If you live in the United States you have a 1 in 6 chance to get sick (each year) from food and yet the United States has one of the safest food supplies in the world. The FDA Food Safety Modernization Act (FSMA) was signed into law by President Obama on January 4, 2011. Its goal was to ensure the U.S. food supply is safe by shifting the focus of the federal Food and Drug Administration (FDA) regulators from responding to contamination to preventing it.

The law provided the FDA with new powers intended to achieve higher compliance with prevention and risk-based food safety standards, and to better respond to and contain problems when they do occur. The law also gave the FDA tools to hold imported foods to the same standards as domestic foods and directs FDA to build an integrated national food safety system in partnership with state and local authorities. Now as we approach the third anniversary of the law, Consumer Reports has released their latest study on the safety of chicken sold in supermarkets.

Consumer Reports bought chicken breasts from major national grocery chains, big box stores like Costco, and regional markets in 26 states. In all they tested 316 samples of chicken breasts. Of those samples, 252 samples were from conventionally produced chicken, 40 samples that were antibiotic free and 24 samples that were certified organic. The analysis found that chicken from the four largest brands (Perdue, Pilgrim's, Sanderson Farms, Tyson) "contained worrisome amounts of bacteria." Consumer reports states that “almost none of the brands were free of bacteria,” and they found “no significant difference in the average number of types of bacteria” between conventional and organic. Their tests did not find any brands or types of chicken breast that had fewer bacteria than the rest.

Consumer Reports testing found E. coli , enterococcus, campylobacter, klebsiella pneumonia, salmonella and staphylococcus aureus. More than half the chicken breasts were tainted with fecal contaminants that can cause blood and urinary-tract infections. Enterococcus was the most common bacterium found appearing in almost 80% of samples. E. coli, was found in over 65% of the chicken breasts; campylobacter, 43 %; klebsiella pneumoniae, in almost 14%; salmonella in nearly 11% of samples, and staphylococcus aureus, in over 9% of chicken samples.

In addition, almost 50% of the chicken breasts tested positive for at least one multidrug-­resistant bacterium, and 11.5%­ carried two or more types of multidrug-­resistant bacteria. In a newly released paper published in the New England Journal of Medicine, Adian Hollis and co-author Ziana Ahmed state that in the United States 80 % of the antibiotics used in the country are consumed in agriculture and aquaculture for the purpose of increasing food production. "Modern medicine relies on antibiotics to kill off bacterial infections," explains Hollis. "This is incredibly important. Without effective antibiotics, any surgery – even minor ones – will become extremely risky. Cancer therapies, similarly, are dependent on the availability of effective antimicrobials. Ordinary infections will kill otherwise healthy people." Bacteria that can effectively resist antibiotics will thrive, reproduce rapidly and spread in various ways including through the food supply as seen last summer with the Tysons chicken antibiotic resistant and virulent salmonella strain that sent almost 40% of sickened people to the hospital.

Salmonella Enteritidis may be found in the intestinal tracts of livestock, poultry, dogs, cats, and other warm-blooded animals. This strain is only 1 of about 2,000 kinds of Salmonella bacteria; it is often associated with poultry and shell eggs. Staphylococcus aureus can be carried on human hands, in nasal passages, or in throats. The bacteria are typically found in foods made by hand and then improperly refrigerated, but clearly are found where raw chicken meat is processed into breasts. One of the staphylococcus aureus found in the Consumer Reports testing was a methicillin-resistant staph aureus better known as MRSA the antibiotic resistant hospital infection. Campylobacter jejuni is one of the most common causes of diarrheal illness in humans. Preventing cross-contamination and using proper cooking methods reduces infection by this bacterium.

E. coli is an indicator organism for fecal matter, but does not necessarily mean the product is, in fact, contaminated by feces. E. coli that is present in feathers, or environmental contaminants, like dust, can also contaminate a poultry carcass. Klebsiella is a type of Gram-negative bacteria that can cause different types of healthcare-associated infections, including pneumonia, bloodstream infections, wound or surgical site infections, and meningitis. Klebsiella bacteria are normally found in the human intestines (where they do not cause disease). They are also found in human stool (feces) and were found in the chicken tested.

The Consumer Report test results found increased and more widespread contamination than previous tests. Half the bacterium found was drug resistant. This is a symptom that our food supply is becoming less safe. Precautions must be taken when handling and preparing food. The US Department of Agriculture recommends four food safety steps in their Food Safe Families campaign.
  1. Clean: Wash hands and surfaces often.
  2. Separate: Separate raw meats and poultry from other foods.
  3. Cook: Cook all poultry to an internal temperature of 165 °F (73.9 °C).
  4. Chill: Refrigerate promptly.
Washing raw poultry before cooking it is not recommended despite what my mother and probably your grandmother recommended. Bacteria in raw meat and poultry juices can be spread to other foods, utensils, and surfaces. This is called cross-contamination. Rinsing or soaking chicken does not destroy bacteria. Only cooking will destroy any bacteria that might be present on fresh chicken.

Another option that has not been very popular with environmentalists and may have other concerns is irradiation. In 1992, the USDA approved a rule to permit the irradiation of raw, fresh, or frozen packaged poultry to control bacteria on raw poultry that can cause illness when poultry is under-cooked or otherwise mishandled. Irradiation at 1.5 to 3.0 kilo Gray, the smallest, most practical “dose,” would eliminate more than 99 % of Salmonellae organisms on the treated poultry. Right now that is sounding pretty good and you might want to consider that if you are not meticulous in your handling of food in your kitchen. Packages of irradiated chicken are easily recognizable at the store because they must carry the international radura symbol along with the statement, “treated with irradiation” or “treated by irradiation.”

Monday, May 27, 2013

Drug Resistant Bacteria Spreads to Our Waters


Drug resistant infections were first identified in 1960 in hospitals and called hospital-acquired MRSA (Methicillin-resistant S. aureus). MRSA causes difficult-to-treat and potentially fatal bacterial infections in hospital patients, and is sometimes referred to as a “superbug.”  However, in the late 1990s, MRSA infections began to appear outside the hospital setting in the greater community in otherwise healthy people who had not been in a hospital and had no other known risks for these kinds of infections. The incidence of these so called “community-acquired” MRSA infections has been increasing in the United States.

Peopled infected with MRSA shed the bacteria from the nose, feces, and skin; therefore, MRSA can end up in municipal wastewater streams after being washed down the drain or flushed down the toilet and spread in ways beyond direct contact.  Several scientists led by researchers at the University Of Maryland School Of Public Health, have performed a study that was published last November showing that it is possible that municipal waste­water could be a reservoir of this micro-­organism. The scientists tested water entering and leaving four unnamed waste water treatment plants, WWTPs. The mid Atlantic ones were probably Back River in Baltimore and possibly Sykesville based on their descriptions. 

They found that MRSA, as well as a related pathogen, methicillin-susceptible Staphylococcus aureus, MSSA, were present in the waste water inflow at all four WWTPs. MRSA was found to be present in 83% of the raw sewage samples taken at the plants. The percentage of MRSA and MSSA positive samples decreased as treatment within the WWTP progressed. Only one WWTP was found to have MRSA bacteria in the treated water leaving the plant, and this was at a plant that does not regularly use chlorination, a tertiary step in wastewater treatment.

In WWTPs Primary Treatment consists of sedimentation and screening of large debris using screens and large settling tanks. Until 1960’s primary treatment was the only form of sewage treatment in most sewage plants. Secondary treatments usually include biological and/or chemical treatment. One of the most common biological treatments is the activated sludge process; in which primary wastewater is mixed with bacteria that break down organic matter and cleans the water. Oxygen is pumped into the mixture. A clarifying tank allows sludge to settle to the bottom and then the treated wastewater moves on for tertiary treatment. Coagulation, filtration and disinfection take place in tertiary treatment. A coagulant is added, the commonly used high-lime process can reduce phosphorus to below 0.10 mg/L. This process also serves as a barrier to viruses, captures organics leaving secondary treatment, and precipitates heavy metals and other suspended particles. Coagulation is followed by filtration which removes organic matter, microorganisms, minerals and excess nutrients. The finalbarrier to pathogens is a chlorination and dechlorination process. 

As the University of Maryland scientists showed, plants that do not use the chlorination process could potentially be releasing disease causing bacteria into the environment.  As waste water is recycled more and more this raises concerns for the safety of the greater community being exposed to undertreated recycled water or bio solids. The odds of samples being MRSA-positive decreased as treatment progressed: 10 of 12 (83%) influent samples were MRSA-positive, while only one of 12 (8%) effluent samples was MRSA-positive. This study makes clear the need to upgrade all waste water treatment plants to advanced waste water treatment plants that use disinfection with chlorine and to eliminate the storm related untreated releases of dilute sewage by our older cities combined sewer systems. Not addressed in the study was the survival of MRSA in bio-solids, it can only be inferred to be a possibility. Our WWTPs must also be upgraded to advanced treatment of the residual sludge to Class A to ensure all bacteria is killed before the sludge is released to the greater environment and human exposure. Not all WWTP treat all their bio solids to that level, but it is possible and should be done. The city of Alexandria is an example of a plant that treats all Biosolids to Class A Exceptional Quality with even higher standards and is safe for use in community settings.

 It is possible to reuse and recycle waste water safely. Since 1978, the upper Occoquan Sewage Authority in Northern Virginia has been discharging recycled water into a stream above Occoquan Reservoir, one of the two potable water supply sources for Fairfax County, Virginia. Recycled water has been part of the Occoquan supply for 34 years and chances are if you are in Fairfax, parts of Prince William and Loudoun counties you have been regularly drinking recycled water. However, this water is always treated with tertiary treatment that includes chlorination and dechlorination before it is released back into the Occoquan and Fairfax Water fully treats and tests all water delivered as potable. The Occoquan Watershed Policy not only specified the type of waste treatment practices that would have to be adopted on a basin-wide scale, but provided for an on-going program of water quality monitoring to measure the success (or failure) of the waste water treatment. The Occoquan Watershed Laboratory (OWL), operated by the Virginia Polytechnic Institute Department of Civil Engineering conducts comprehensive studies of the Occoquan water quality, and effects of the waste water treatment effluents.

Noman M. Cole, Jr. Pollution Control Plant in Fairfax,Virginia is now engaged in a direct water recycling program, reusing treatedwastewater for landscape irrigation and industrial processes. The Noman Cole plant is engaged in the Water Reuse Project also known as the Purple Pipe Project, to directly reuse some of the water. (The pipes are colored purple to designate the water as non-potable, but have undergone chlorination to ensure water safety.) The Purple Pipe project has completed the first phase of the project and is delivering 1.4-1.6 million gallons of fully treated waste water to the Covanta Fairfax, Inc. Resource Recovery Plant and Laurel Hill Golf Course. 

The paper Methicillin-Resistant Staphylococcus aureus (MRSA) Detected at Four U.S. Wastewater Treatment Plants was written by Rachel E. Rosenberg Goldstein, Shirley A. Micallef, Shawn G. Gibbs, Johnnie A. Davis,Xin He, Ashish George, Lara M. Kleinfelter,Nicole A. Schreiber, Sampa Mukherjee, Amir Sapkota,Sam W. Joseph, and Amy R. Sapkota and published in the November 2012 issue of Environmental Health Perspectives