Superbug MRSA Identified in U.S. Wastewater Treatment Plants

The School of Public Health News

November 5, 2012

NEWS RELEASE

Contact: Kelly Blake, kellyb@umd.edu, 301-405-9418

 

University of Maryland-led study is first to document environmental source of the antibiotic-resistant bacteria in the United States

 

College Park, Md.–A team led by researchers at the University of Maryland School of Public Health has found that the “superbug” methicillin-resistant Staphylococcus aureus (MRSA) is prevalent at several U.S. wastewater treatment plants (WWTPs). MRSA is well known for causing difficult-to-treat and potentially fatal bacterial infections in hospital patients, but since the late 1990s it has also been infecting otherwise healthy people in community settings.

 

“MRSA infections acquired outside of hospital settings–known as community-acquired MRSA or CA-MRSA–are on the rise and can be just as severe as hospital-acquired MRSA. However, we still do not fully understand the potential environmental sources of MRSA or how people in the community come in contact with this microorganism,” says Amy R. Sapkota, assistant professor in the Maryland Institute for Applied Environmental Health and research study leader. “This was the first study to investigate U.S. wastewater as a potential environmental reservoir of MRSA.”

 

Because infected people can shed MRSA from their noses and skin and through their feces, wastewater treatment plants are a likely reservoir for the bacteria. Swedish researchers have previously identified the presence of MRSA in WWTPs in Sweden, and this new UMD-led study confirms the presence of MRSA in U.S. facilities. The study was published in the November issue of the journal Environmental Health Perspectives.

 

The research team, including University of Maryland School of Public Health and University of Nebraska Medical Center researchers, collected wastewater samples throughout the treatment process at two Mid-Atlantic and two Midwestern WWTPs. These plants were chosen, in part, because treated effluent discharged from these plants is reused as “reclaimed wastewater” in spray irrigation activities. The researchers were interested in whether MRSA remained in the effluent.

 

 

They found that MRSA, as well as a related pathogen, methicillin-susceptible Staphylococcus aureus (MSSA),were present at all four WWTPs, with MRSA in half of all samples and MSSA in 55 percent.MRSA was present in 83 percent of the influent– the raw sewage–at all plants, butthe percentage of MRSA- and MSSA-positive samples decreased as treatment progressed. Only one WWTP had the 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.

 

Ninety-three percent of the MRSA strains that were isolated from the wastewater and 29 percent of MSSA strains were resistant to two or more classes of antibiotics, including several that the U.S. Food and Drug Administration has specifically approved for treating MRSA infections. At two WWTPs, MRSA strains showed resistance to more antibiotics and greater prevalence of a gene associated with virulence at subsequent treatment stages, until tertiary chlorination treatment appeared to eliminate all MRSA. This suggests that while WWTPs effectively reduce MRSA and MSSA from influent to effluent, they may select for increased antibiotic resistance and virulence, particularly at those facilities that do not employ tertiary treatment (via chlorination).

 

“Our findings raise potential public health concerns for wastewater treatment plant workers and individuals exposed to reclaimed wastewater,” says Rachel Rosenberg Goldstein, environmental health doctoral student in the School of Public Health and the study’s first author. “Because of increasing use of reclaimed wastewater, further research is needed to evaluate the risk of exposure to antibiotic-resistant bacteria in treated wastewater.”

 

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.

 

For more information, please contact Kelly Blake, communications director for the School of Public Health at kellyb@umd.edu or (301) 405-9418.

 

 

Hypertension and cholesterol medications present in water released into the St. Lawrence River

2009 study posted for filing

Contact: Julie Gazaille
j.cordeau-gazaille@umontreal.ca
514-343-6796
University of Montreal

Universite de Montreal research team on the water upstream and downstream from the Montreal wastewater

This press release is available in French.

Montreal, January 26, 2009 – A study conducted by Université de Montréal researchers on downstream and upstream water from the Montreal wastewater treatment plant has revealed the presence of chemotherapy products and certain hypertension and cholesterol medications.

Bezafibrate (cholesterol reducing medication), enalapril (hypertension medication), methotrexate and cyclophosphamide (two products used in the treatment of certain cancers) have all been detected in wastewater entering the Montreal treatment station. However, only bezafibrate and enalapril have been detected in the treated water leaving the wastewater treatment plant and in the surface water of the St. Lawrence River, where the treated wastewater is released.

This study was conducted due to the sharp rise in drug consumption over the past few years. In 1999, according to a study by IMS Health Global Services, world drug consumption amounted to $342 billion. In 2006 that figure doubled to $643 billion. A significant proportion of the drugs consumed are excreted by the human body in urine and end up in municipal wastewater. Chemotherapy products, such as methotrexate, are excreted by the body practically unchanged (80 to 90 percent in their initial form).

Chemotherapy for fish?

The pharmaceutical compounds studied were chosen because of the large quantities prescribed by physicians. “Methotrexate and cyclophosphamide are two products very often used to treat cancer and are more likely to be found in water,” says Sébastien Sauvé, a professor of environmental chemistry at the Université de Montréal. “Even though they treat cancer, these two products are highly toxic. This is why we wanted to know the extent to which the fauna and flora of the St. Lawrence are exposed to them.”

Method and quantities

Professor Sauvé’s team validated a rapid detection method (On-line SPE-LC-MS/MS ) (1) for pharmaceutical compounds under study in the raw and treated wastewater of the Montreal wastewater treatment plant.

The quantities of bezafibrate and enalapril detected in the raw wastewater, treated wastewater and surface water at the treatment station outlet are respectively 50 nanograms per litre, 35 ng L and 8 ng L for bezafibrate and 280 ng L, 240 ng L and 39ng L for enalapril.

“All in all, these quantities are minimal, yet we don’t yet know their effects on the fauna and flora of the St. Lawrence,” Professor Sauvé explains. “It is possible that some species are sensitive to them. Other ecotoxicological studies will be necessary. As for the chemotherapy products detected in the raw wastewater but not in the treated wastewater, one question remains: did we not detect them because the treatment process succeeded in eliminating them or because our detection method is not yet sophisticated enough to detect them?”

A new threat to the aquatic environment

The release locations of wastewaters treated by the treatment stations are the main source of drug dispersion into the environment. Because of their high polarity and their acid-base character, some of the pharmaceutical compounds studied have the potential to be transported and dispersed widely in the aquatic environment. In Montreal, the wastewater treatment station treats a water volume representing 50 percent of the water treated in Quebec and has a capacity of about 7.6 million cubic metres per day, making it the largest physicochemical treatment station in the Americas. This is why it is important to develop a simple, rapid, precise and inexpensive method, Professor Sauvé points out.

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This study was published in the Journal of Environmental Monitoring and produced by researchers from the Department of Chemistry of the Université de Montréal and the Environment Canada Aquatic Ecosystem Protection Research Division. It was funded by the Natural Sciences and Engineering Research Council of Canada, the National Council for Science and Technology of Mexico, the Canada Foundation for Innovation, the St. Lawrence Action Plan and Health Canada’s Chemicals Management Plan.

(1)On-line solid-phase extraction liquid chromatography coupled to polarity-switching electrospray tandem mass spectometry

On the Web:

About the Université de Montréal: www.umontreal.ca/english/index.htm

To consult the complete study: www.rsc.org/Publishing/Journals/EM/article.asp?doi=b817570e

Note: Professor Sauvé is available for interviews on Monday and Tuesday, January 26th and 27th

Prions are not degraded by conventional sewage treatment processes

Re-Posted  for filing 2008
Contact: Michael Woods
m_woods@acs.org
202-872-4400
American Chemical Society

Persistence of Pathogenic Prion Protein during Simulated Wastewater Treatment Processes

IMAGE:Wastewater treatment plants do not reduce harmful proteins called prions that cause incurable brain infections, such as Mad Cow disease, scientists report.

Click here for more information. 

 
Environmental Science & Technology

Scientists in Wisconsin are reporting in a paper scheduled for the July 1 issue of ACS’ Environmental Science & Technology that typical wastewater treatment processes do not degrade prions. Prions, rogue proteins that cause incurable brain infections such as Mad Cow disease and its human equivalent, variant Creutzfeldt-Jakob Disease, are difficult to inactivate, resisting extreme heat, chemical disinfectants, and irradiation. Until now, scientists did not know whether prions entering sewers and septic tanks from slaughterhouses, meatpacking facilities, or private game dressing, could survive and pass through conventional sewage treatment plants.

Joel Pedersen and colleagues used laboratory experiments with simulated wastewater treatment to show that prions can be recovered from wastewater sludge after 20 days, remaining in the “biosolids,” a byproduct of sewage treatment sometimes used to fertilize farm fields.

Although emphasizing that prions have never been reported in wastewater treatment plant water or biosolids, the researchers note that existing tests are not sufficiently sensitive to detect the extremely low levels of prions possible in those materials. — AD

ARTICLE #1 FOR IMMEDIATE RELEASE “Persistence of Pathogenic Prion Protein during Simulated Wastewater Treatment Processes”

DOWNLOAD FULL TEXT ARTICLEhttp://dx.doi.org/10.1021/es703186e

CONTACT:
Joel A. Pedersen, Ph.D.
University of Wisconsin
Madison, Wisconsin
Phone: (608) 263-4971
Fax: (608) 265-2595
Email: japedersen@soils.wisc.edu

New study links fate of personal care products to environmental pollution and human health concerns: Triclosan

Contact: Joe Caspermeyer
joseph.caspermeyer@asu.edu
480-727-0369
Arizona State University

Parental concerns in maintaining germ-free homes for their children have led to an ever-increasing demand and the rapid adoption of anti-bacterial soaps and cleaning agents. But the active ingredients of those antiseptic soaps now have come under scrutiny by the EPA and FDA, due to both environmental and human health concerns.

Two closely related antimicrobials, triclosan and triclocarban, are at the center of the debacle. Whereas triclosan (TCS) has long captured the attention of toxicologists due to its structural resemblance to dioxin (the Times Beach and Love Canal poison), triclocarban (TCC) has ski-rocketed in 2004 from an unknown and presumably harmless consumer product additive to one of today’s top ten pharmaceuticals and personal care products most frequently found in the environment and in U.S. drinking water resources.

Now, Biodesign Institute at Arizona State Univesity researcher Rolf Halden and co-workers, in a feat of environmental detective work, have traced back the active ingredients of soaps – used as long ago as the 1960s – to their current location, the shallow sediments of New York City’s Jamaica Bay and the Chesapeake Bay, the nation’s largest estuary.

“Our group has shown that antimicrobial ingredients used a half a century ago, by our parents and grandparents, are still present today at parts-per-million concentrations in estuarine sediments underlying the brackish waters into which New York City and Baltimore discharge their treated domestic wastewater,” said Halden, a new member of the institute’s Center for Environmental Biotechnology. “This extreme environmental persistence by itself is a concern, and it is only amplified by recent studies that show both triclosan and triclocarban to function as endocrine disruptors in mammalian cell cultures and in animal models.”

Aiding in his team’s research was another type of contamination: the radioactive fallout from nuclear testing conducted in the second half of the last century. Using the known deposition history and half-lives of two radioactive isotopes, cesium-137 and beryllium-7, Halden and his collaborators Steven Chillrud, Jerry Ritchie and Richard Bopp were able to assign the approximate time at which sediments observed to contain antimicrobial residues had been deposited in the two East Coast locations.

By analyzing vertical cores of sediment deposited over time in the two sampling locations on the East Coast, they showed that TCC, and to a lesser extent, TCS, can persist in estuary sediments. TCC was shown to be present at parts per million levels, which could represent unhealthy levels for aquatic life, especially the bottom feeders that are important to commercial fishing industries like shellfish and crabs.

In the Chesapeake Bay samples, the group noticed a significant drop in TCC levels that corresponded to a technology upgrade in the nearby wastewater treatment plant back in 1978. However, earlier work by the team had shown that enhanced removal of TCC and TCS in wastewater treatment plants leads to accumulation of the problematic antimicrobial substances in municipal sludge that often is applied on agricultural land for disposal. Lead author Todd Miller concludes that “little is actually degraded during wastewater treatment and more information is needed regarding the long term consequences these chemicals may have on environmentally beneficial microorganisms.”

Along the way of studying the deposition history of antimicrobials in sediments, the team also discovered a new pathway for the breakdown of antimicrobial additives of consumer products. Deep in the muddy sediments of the Chesapeake Bay, they found evidence for the activity of anaerobic microorganisms that assist in the decontamination of their habitat by pulling chlorine atoms one by one off the carbon backbone of triclocarban, presumably while obtaining energy for their metabolism in the process. “This is good news,” said Halden, “but unfortunately the process does not occur in all locations and furthermore it is quite slow. If we continue to use persistent antimicrobial compounds at the current rate, we are outpacing nature’s ability to decompose these problematic compounds.”

While combining bioenergy production and pollutant destruction has its own appeal, Halden sees a simpler solution to combating the pollution his team discovered: limit the use of antimicrobial personal care products to situations where they improve public health and save lives.

“The irony is that these compounds have no measurable benefit over the use of regular soap and water for hand washing; the contact time simply is too short.” Unfortunately this cannot be said for the bottom-dwelling organisms in the sampling locations on the East Coast. “Here,” Halden concludes, “the affected organisms are experiencing multi-generational, life-time exposures to our chemical follies.”

Halden is planning to continue his research on persistent antimicrobials by studying their body burden and associated health effects in susceptible populations including mothers and their babies.

 

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“Fate of Triclosan and Evidence for Reductive Dechlorination of Triclocarban in Estuarine Sediments” is an original research paper currently in press in the peer-reviewed journal Environmental Science & Technology. The work was funded in part by the Johns Hopkins Center for a Livable Future and the National Institute of Environmental Health Sciences. The study’s authors are T. R. Miller, J. Heidler, S. N. Chillrud, A. DeLaquil, J. C. Ritchie, J. N. Mihalic, R. Bopp, and R. U. Halden.

Tamiflu survives sewage treatment ( oseltamivir )

Contact: Jerker Fick jerker.fick@chem.umu.se 46-480-446-225 Public Library of Science

Swedish researchers have discovered that oseltamivir (Tamiflu); an antiviral drug used to prevent and mitigate influenza infections is not removed or degraded during normal sewage treatment. Consequently, in countries where Tamiflu is used at a high frequency, there is a risk that its concentration in natural waters can reach levels where influenza viruses in nature will develop resistance to it. Widespread resistance of viruses in nature to Tamiflu increases the risk that influenza viruses infecting humans will become resistant to one of the few medicines currently available for treating influenza.

”Antiviral medicines such as Tamiflu must be used with care and only when the medical situation justifies it,” advises Björn Olsen, Professor of Infectious Diseases with the Uppsala University and the University of Kalmar. “Otherwise there is a risk that they will be ineffective when most needed, such as during the next influenza pandemic.”

The Swedish research group demonstrated that oseltamivir, the active substance in Tamiflu, passes virtually unchanged through sewage treatment.

“That this substance is so difficult to break down means that it goes right through sewage treatment and out into surrounding waters,” says Jerker Fick, Doctor in Chemistry at Umeå University and the leader of this study.

The Swedish research group also revealed that the level of oseltamivir discharged through sewage outlets in certain countries may be so high that influenza viruses in nature can potentially develop resistance to the drug.

“Use of Tamiflu is low in most countries, but there are some exceptions such as Japan, where a third of all influenza patients are treated with Tamiflu,” explains Jerker Fick.

Influenza viruses are common among waterfowl, especially dabbling ducks such as mallards. These ducks often forage for food in water near sewage outlets. Here they can potentially encounter oseltamivir in concentrations high enough to develop resistance in the viruses they carry.

“The biggest threat is that resistance will become common among low pathogenic influenza viruses carried by wild ducks.” adds Björn Olsen.  These viruses could then recombinate with viruses that make humans sick to create new viruses that are resistant to the antiviral drugs currently available.

The Swedish researchers advise that this problem must be taken seriously so that humanity’s future health will not be endangered by too frequent and unnecessary prescription of the drug today.

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Disclaimer

This press release refers to an upcoming article in PLoS ONE. The release has been provided by the article authors and/or their institutions.  Any opinions expressed in this are the personal views of the contributors, and do not necessarily represent the views or policies of PLoS. PLoS expressly disclaims any and all warranties and liability in connection with the information found in the release and article and your use of such information.

Their study was published in the high-ranked journal PLoS ONE. The entire article is available free online, and can be read at the following address: http://www.plosone.org/doi/pone.0000986

Citation: Fick J, Lindberg RH, Tysklind M, Haemig PD, Waldenstro¨m J, et al (2007) Antiviral Oseltamivir Is not Removed or Degraded in Normal Sewage Water Treatment: Implications for Development of Resistance by Influenza A Virus. PLoS ONE 2(10): e986. doi:10.1371/journal.pone.0000986

PLEASE ADD THE LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (URL live from October 2): http://www.plosone.org/doi/pone.0000986

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ASU study finds antimicrobials from personal care products in statewide survey of Minnesota’s rivers and lakes – triclosan

Highlights

  • First statewide U.S. survey finds antimicrobial compounds present in sediments of Minnesota’s rivers, creeks and lakes
  • Personal care product active ingredients triclosan (TCS) and triclocarban (TCC) detected in all samples takenupstreamanddownstreamof wastewater treatment plants
  • Among the two known endocrine disruptors monitored, triclocarban was more abundant than triclosan
  • Study adds tobody of scientific work calling into question the widespread use of antimicrobial compounds that offer nomeasurable benefit for the average consumer

In our zest for cleanliness, have we permanently muddied our nation’s waters?     A science team from Arizona State University, in collaboration with federal partners, has completed the first statewide analysis of freshwater bodies in Minnesota, finding widespread evidence of the presence of active ingredients of personal care products in Minnesota lakes, streams and rivers.   These products are a billion dollar industry and can be found in antimicrobial soaps, disinfectants, and sanitizers to scrub our hands and clean countertops. Hundreds of antimicrobial products are sold in the U.S., many marketed with efficacy claims that remain elusive due to the short duration of the average consumer’s handwashing practices. The fate of these products can be traced from home use to sewers to wastewater treatment plants to eventually, downstream bodies of water.    The research team focused on two active ingredients found prominently in anti-bacterial soaps −triclosan and triclocarban− which have come under scrutiny by the EPA and FDA due to their environmental and human health concerns. These compounds persist for decades in the environment, and both triclocarban and triclosan are among the top ten pharmaceuticals and personal care products most frequently found in the environment and in U.S. drinking water resources.

“This study underscores the extent to which additives of antimicrobial consumer products are polluting freshwater environments in the U.S.; it also shows natural degradation processes to be too slow to counter the continuous environmental release of these endocrine disrupting chemicals,” said Halden, director of Environmental Security at the Biodesign Institute and professor in the Ira A. Fulton School of Sustainable Engineering and the Built Environment. Halden’s research focuses on the interconnectedness of the water cycle and human health, with specialemphasis on the role of manmade products and human lifestyle choices on environmental quality.

In a previous study, Halden’s team found significant concentrations of harmful soap-related chemicals dating back to the 1950’s in sediments of Jamaica Bay and Chesapeake Bay, into which New York City and Baltimore discharge their treated domestic wastewater, respectively.

Upon their use, triclosan and triclocarban are absorbed through the skin and hence contaminate human blood, urine, and even breast milk. Ultimately, these chemicals together with the pharmaceuticals we use end up in our sewage and surface waters. In 2002, the USGS published a landmark study that showed 80 percent of 139 streams sampled from across 30 U.S. states were found to contain measurable levels of organic wastewater contaminants. The human health risks associated with these personal care product chemicals are still not fully understood despite them being used for decades.

In the ASU study, river, creek and lakebed sediment samples from 12 locations upstream and downstream of wastewater treatment plants were analyzed for the presence of antimicrobial compounds.

For Halden’s team, which consisted of postdoctoral researcher Benny Pycke, environmental engineering graduate student and first author Arjun Venkatesan, the results showed that overall concentrations of triclocarban were 3- to 58-times higher than those of the more frequently monitored triclosan.

“We were able to detect these two compounds both upstream and downstream of suspected input sources, and the levels of the antimicrobial soap ingredient triclocarban were usually higher compared to triclosan,” said Venkatesan. “Although triclosan is used in a larger number of formulations and personal care products, we found triclocarban to be more abundant in freshwater environments.” The team also found degradation products of TCC but transformation of this antimicrobial is known to be very slow in natural environments.

“Also, we expected to find these compounds mostly downstream of wastewater treatment plants; but when we consistently found detectable levels upstream and downstream, we realized that there are probably multiple sources contributing to the contamination of these sites, potentially including additional wastewater treatment plants further upstream and runoff from sites where antimicrobial-laden sewage sludge had been applied.”

“Every site is essentially downstream of something,” added Pycke. A site in the immediate vicinity of a wastewater treatment plant near Duluth (St. Louis Bay at Lake Superior) had the greatest concentration of triclocarban and its lower chlorinated derivatives, and the Duluth site and Shagawa Lake site had concentrations three times higher than river and creek sediments. There was a strong correlation between the level of contamination with wastewater treatment plant discharge, stream flow and the population density of the surrounding region.

“As the name suggests, these antimicrobial compounds (triclosan and triclocarban) are incompatible with biological wastewater treatment infrastructure paid for with tax dollars,” said Halden. “Municipalities in Minnesota and across the U.S. work hard using state?of?the?art equipment to keep our freshwater environments clean but they cannot control what consumers, misled by aggressive marketing, discharge into the sewage collection system.”

Wherever antimicrobial personal care products are in use, water and sediment have been contaminated, a situation that certainly is not unique to the state of Minnesota. “Regulatory agencies are aware of the overuse of antimicrobials but no state or federal restrictions have been implemented yet for either triclosan or triclocarban,” said Halden. “Aside from ecological concerns, widespread environmental occurrence of antimicrobials also is a potential public health concern because unwarranted use of antimicrobials can promote drug resistance of human pathogens.”

Halden’s research is developing engineering solutions to clean up environments impacted by antimicrobial compounds. However, he emphasizes that the best solution right now in combating this pollution is for consumers to limit their use of antimicrobial personal care products that, ironically, provide no measurable health benefits to the average consumer, as determined by an expert panel convened by the Food and Drug Administration in 2005.

For this project, ASU was supported by funding from the National Institute of Environmental Health Sciences.

In addition to Halden’s appointment as Director of Environmental Security at ASU’s Biodesign Institute, he holds the title of professor in the School of Sustainable Engineering and the Built Environment, at the Ira. A. Fulton Schools of Engineering, ASU, and adjunct associate professor of Environmental Health Sciences, at the Johns Hopkins Bloomberg School of Public Health.