Dr. Edo McGowan, medical geo-hydrology, shared the following thoughts in response to the Becker's ASC Review column "Rhode Island Hospital Researcher Says MRSA Infection May Be Seasonal."
Dr. Edo McGowan: I have not completely absorbed this article within Becker's ASC Review, but it raises some interesting points. This is an East Coast experience and may not reflect our situation out here in California. It may reflect the solar radiation across the seasons and the levels of vitamin D, hence the immune system's ability to counteract bacteria. Rhode Island is north 41 to 42 degrees where as we are at 34 degrees and the level of insolation on the east coast falls off much more rapidly. However, that being said, it could also reflect the trips to beaches and thus the contact with sand. In Florida and Washington State beaches, researchers who went looking for MRSA in beach sand did find it (see Marilyn Roberts). Also sewage outfalls, whether to marine waters or inland surface waters, has been shown to affect beach sands.
We are planning to study one such system here in California. The sewer plant discharges treated sewage effluent to off-shore ocean waters about 500 yards out from the local beach and represents one of three short-shallow outfalls along this immediate California coastline. Scientific research by Heal the Ocean and UCSB has recently demonstrated that the discharged sewage effluent from short-shallow outfalls is capable of returning to the shoreline, potentially contaminating the beach area.
Although state-approved single-indicator laboratory tests indicate no problems, these tests are quite antiquated and neglect to document the presence of several types of human pathogens and/or their genetic material in the beach water and sand. The consequence is that the state lab tests fail to accurately indicate the actual risks to the public. There are several scientific studies that have demonstrated this failure. Such failure is especially critical when it comes to antibiotic resistant pathogens and their genes which can cause serious illness in human beings. In 2010, the presence of MRSA was documented in ocean beach sands of Florida and Washington when scientists actually began to look for MRSA.
Antibiotic resistant infections currently cost the U.S. healthcare system more than $20 billion annually. On a per patient basis the extra cost is between $18 thousand to $29 thousand which includes an extended hospital stay of 6 to 12 days. Just one of the major superbugs, the antibiotic resistant Staphylococcus aureus (MRSA), according to the CDC, now kills more Americans than AIDS. The U.S. Environmental Protection Agency's Wastewater Research Division, Municipal Environmental Research Laboratory in Cincinnati, Ohio has conclusively demonstrated that discharged sewage wastewater, treated or untreated, is a primary contributor of bacteria to the aquatic ecosystem. Studies, in addition to the above research by US/EPA, have been conducted which demonstrate that significant numbers of multiple drug-resistant bacteria are discharged to rivers, bays, bathing beaches, and coastal canals. Waters contaminated by bacteria capable of transferring drug resistance are of great concern since there is the potential for transfer of antibiotic resistance to more dangerous organisms. Sewer plants, as currently designed and operated, cannot adequately contain these bacteria and especially their tiny genetic material. The antibiotic resistant genes are unaffected by chlorine disinfectants at rates now utilized in the sewage treatment. Beach sands, once contaminated, can act as a growth media for pathogens.
Our study group is planning research to evaluate the presence of antibiotic resistant genes in some of our beach sands. If present, such genes can be transferred to normal non-pathogenic bacteria in the sands as well as those on and within humans. In a study of 27,365 beach goers at 7 U.S. beaches, the people who dug in or covered themselves with sand were, in the following week or two, more likely to have diarrheal illnesses due to a variety of organisms. Thus, beach-goers locally may be at increased risk. As to children, they are more likely to dig in sand when at the beach and that may explain why children "were approximately 1.85 times as many community-associated MRSA infections and 2.94 as many hospital-associated MRSA infections in the third and fourth quarters of the year than in the first two quarters."
The above may explain, in part, some of the findings in Rhode Island with MRSA.
