Uganda: Density of Households Without Improved Sanitation Facilities, 2002

In the African nations east of the Nile Cret, there are numerous sewage treatment plants. Uganda may be considered a typical case in point. The discharged effluent has been discussed as a substitute for irrigation water. Reclaimed sewage effluent and its use in the irrigation of agricultural commodities as proposed by some international donors may well be a source of pathogens and antibiotic resistant bacteria causing disease outbreaks. Some crops can up-take pathogens through their roots and thus the pathogens are internalized. This requires cooking, which in fuel-sparse areas, may see the ingestion of commodities in the uncooked state with sufficient pathogen numbers to cause illness. While information on pathogens in reclaimed water is well represented in the literature, many donors may miss this critical aspect. Basically, the standards currently used by the US EPA and WHO which are often seen as the gold standards are badly flawed.

Bacteria exiting sewage treatment plants can withstand the levels of chlorine used in the treatment of released effluents. This often sees these bacteria resuscitate and regain infective capacities once they are released from the sewer plant. The tests often used by regulators do not take these changes into consideration. Thus the findings of standard-dictated tests may vastly understate the true picture. The Water Environment Research Foundation (WERF) which is the research arm of the U.S. wastewater industry looked at this and found that by using other testing methods, the density of bacteria used as indicators of pathogens could be five orders of magnitude greater than the density measured by standard culturing methods. This then makes a fiction of the current standards and their ability to protect public health. As it now stands, infections with antibiotic resistance involved are killing more Americans than AIDS. It should be apparent that current standards used by US EPA do not control for these issues. Below is a reworked part of a memo that was sent to high-level government officials in US EPA, CDC, FDA, and H&HS. The contents may be of interest to those working in the area of water quality within Uganda. This is important for Kampala. It will be remembered that the sewage treatment plant for Kampala had failed for some time because of blown electrical panels. The raw sewage then over-topped the treatment plant and coursed through the marsh, entering Lake Victoria about ¼ mile from the city's fresh water intake.

I have found through non-EPA sources, a published EPA paper written by Meckes in 1982 [see: http://aem.asm.org/cgi/reprint/43/2/371.pdf]. It discusses and demonstrates the production and dissemination of antibiotic resistance by sewage processing and sewage byproducts. Thus it is evident that the US EPA has known about the production and entrainment of antibiotic resistance in sewage and its byproducts since at least the early 1980’s.

EPA, although historically eschewing the issue because for years it claimed that sewage byproducts such as sewage sludge are benign, must begin addressing the public health issues created by antibiotic resistance arising from sewage and its byproducts such as reclaimed water. In essence, how could the agency that promotes the application of sewage sludge across America's farmland also admit that it was spreading antibiotic resistant pathogens across America's farmlands? It could not admit this and save face.

Reclaimed water has been studied by WERF and that study demonstrated that finished reclaimed water contained significant levels of pathogens [see: 9http://aem.asm.org/cgi/content/abstract/71/6/3163] Valerie J. Harwood, et al, 2005,Validity of the Indicator Organism Paradign for Pathogen Reduction in Reclaimed Water and Public Health Protection, Applied and Environmental Microbiology, Vol.71. See also: Joan Rose, et al., 2004 Reduction of pathogens, indicator bacteria, alternative indicators by wastewater treatment and reclamation process, WERF.

There are other factors that compromise the effectiveness for disinfecting pathogens arising in sewer plants. Chang worked with methicillin resistant Staphylococcus aureus (MRSA). He notes that exposure to chlorine in sewer plants causes Staphylococcus aureus to shift genes and in doing so bring out several virulence factors. Virulence factors are forms that a pathogen can take that enhances its capacity to cause disease. Bacteria, in response to chlorine disinfection, often initiate genenomic shifts that enhance bacterial virulence (MW Chang, 2007, see: http://cat.inist.fr/?aModele=afficheN&cpsidt=19219794). This is a normal response by many bacteria. Millions of years of genetic selection facilitate this reaction. When the cells of the body that fight infection attack a pathogen, they enclose that pathogen within a phagosome (a small pouch) and then releases a chlorine-like substance into that pouch to kill the unwanted intruder. Using chlorine over and over in wastewater and drinking treatment plants, especially along America's larger rivers, facilitates the development of chlorine resistance. Thus, through exposure of pathogens to sewer treatment, the resultant augmentation of virulence and chlorine resistance poses a direct threat to the human immune system. If that immune system is already compromised, as is the case within a significant portion of the U.S. public, for example the diabetics and those with insulin resistance, for these citizens, the issues are more complex.

There is some association with citizens of Uganda here as the consumption of sugar has dramatically increased since the initiation of large sugar plantations. Local British expat physicians note that also heart disease has increased since the expansion of sugar plantations. Consequently, it will be important to take a more synoptic view of public health implications of water quality and any association with compromised immune systems.

In the past, it was possible to walk into a local Kampala drug store and self select medications, including antibiotics. This may mean that for those areas of Uganda where there are sewer treatment plants, the levels of antibiotic resistance generated by these plants may be high. Thus it may be that a revolving door is created between the community and the effluent, if that effluent is used for irrigation of crops. There are two major types of antibiotics that can be given to fight infection. One type is called a bactericidal [see : http://en.wikipedia.org/wiki/Bactericide] and penicillin or vancomycin are examples. The others are called bacteriostatic and they do their work not so much by killing pathogens but by arresting their advance while awaiting the human immune system to do the brunt of the work. Chlorine resistance then affects the use of bacteriostatic antibiotics because chlorine resistance also adversely impacts the capacity of the human immune system. An example of a bacteriostatic antibiotics is erythromycin, Thus if one has a compromised immune system and encounters an antibiotic resistant pathogen that is also chlorine resistant, the clinical outlook may become challenging.

So, how fast, from a clinical perspective, can antibiotic resistance develop? Schentag, et al (2003), followed surgical patients with subsequent results. Pre-op nasal cultures found Staphylococcus aureus 100% antibiotic susceptible, i.e., the bacteria were easily killed by antibiotics because they had no antibiotic resistance. Pre-op prophylactic antibiotics were administered. Following surgery, Cephalosporin was administered. Ninety percent of the patients went home at post-op day two without infectious complications. Nasal bacteria counts on these patients had dropped from 10/5th to 10/3rd, but were now a mix of sensitive, borderline, and resistant Staphylococcus sp. By comparison, prior to surgery, all of the patients’ staphylococcus samples had been susceptible to antibiotics. For the patients remaining in the hospitals and who were switched on post-op day 5 to a second generation cephalosporin (Ceftazidine), these demonstrated bacterial counts up to 1,000-fold when assayed on post-op day 7 and most of these were methicillin resistant Staphylococcus aureus (MRSA). These patients were switched to a two week course of vancomycin. Cultures from those remaining in the hospital on day 21 revealed vancomycin resistant enterococcus (VRE) and Candida spp. Vancomycin resistant enterococci infections can produce mortality rates of between 42% and 81%.

Note in the above, that these patients harbored NO resistant bacteria in their nasal cavities upon entry to the hospital. But what would be the result if there had been inadvertent acquisition of resistance from environmental contamination such as through crops irrigated with recycled water? This also then brings into question the current paradigm on infection and its dose response to a certain load of a particular pathogen, i.e. ID-50. Lateral transfer (gene exchange between bacteria) of mobile genetic elements conferring resistance is not considered in this old paradigm. With the prodigious capacity for the gut bacteria to multiply once the lateral transfer has taken place, very small numbers – well below the old paradigms – can be multiplied into impressive numbers over night. If you want to run the math, double the number 1 and keep doubling the result every 20 minutes for 24 hours and see the enormous number that results. The bacteria that live in the gut are about 10 times more numerous that the total number of cells that make up your body. Since viruses and phages are also involved, their capacity to multiply, which dwarfs that of bacteria, must also be included. Thus, there is a need for a new paradigm. Unfortunately the regulatory community does not seem to recognize this.

When one considers multiplication within sewer plants and also within their byproducts, disbursement into the environment, the transfer to background to organisms, hence to man and his animals and then the re-multiplication within the gut flora, the emerging picture is worrisome.

This memo, therefore, contends that this unconsidered avenue for the spread of antibiotic resistance needs greater awareness within the donor community working in developing nations. The Meckes paper needs to be brought out and circulated in a transparent fashion by the US EPA which then needs to initiate standards for dealing with antimicrobial resistance in sewage processing and sewage byproducts such as reclaimed water. This will be an enormous challenge because it means that we must admit that, as currently designed and operated, almost all sewer plants are failing to protect public health. It also means that the current infrastructure improvement, unless new designs for sewer plants are proposed that take into consideration the above, the money may well be wasted. Without the perspective of a broader analysis of this issue, future policy may be no more than the post-hoc rationalization for a series of missed opportunities. It would seem reckless to proceed without a broader picture.

Dr Edo McGowan