Sludge Watch ==> Multi resistant bacteria develop in sewage treatment plants

[M Reilly]

Draft: Guide for the Beneficial Use of  Non-Agricultural Source Material on
Agricultural Land"
To Nina Koskenoja of the MoE Waste Management Branch.

Fm: Dr Edward McGowan
c/o 455 Thiel St, London, Ont .
#PA04E0008


 Here is the summary:



Another and less well understood mechanism for the transfer of multi-drug
resistant bacteria is found at the local sewer treatment plant. As bacteria
wind their way through these treatment processes, the selective pressures
against them increase. In consequence, there is a greater effort by bacteria
to pass on survival enhancing genetic information. Additionally, as the
environmental stresses increase, the bacteria up-regulate numerous other
survival mechanisms to assure that they and their genetic material survive.
These can include chlorine resistance.

In one of the several major studies looking at this, the scientists followed
bacteria through a sewer treatment works. Fecal coliforms were the test
organism. These bacteria were isolated at various locations in the plant as
the sewage was passing through the treatment process. They were isolated
from: a) the inlet, b) the primary sedimentation tank, c) the activated
sludge digestion tank, d) the final settling tank, e) the outlet and f) the
return activated sludge drain. They were then examined for multi-drug
antibiotic resistance. The study looked for the presence of drug resistant
plasmids. The scientists were able to distinguish resistant bacteria from
those still sensitive to antibiotics. Several drugs were tested and included
tetracycline, kanamycin, chloramphenicol and streptomycin, ampicillin,
nalidixic acid, rifampicin, and sulfisoxazole. We have seen above, the big
gun—vancomycin is now in trouble. A total of 900 separate tests were
conducted. Of these over half contained multi-drug resistant plasmids.



While this is interesting, there was a new finding that raised considerable
concern. The further along that the wastewater had progressed through the
treatment process the greater the tendency was development of multiresistant
strains. Additionally, the study demonstrated that these multi-resistant
bacteria also simultaneously carried, and then passed around their multiple
transferable drug-resistance plasmids. Thus, the take-home message is that
drug resistance and the transfer of multi-drug resistant occurs in
wastewater treatment plants. [Nippon Koshu Eisei Zasshi 1990
Feb;37(2):83-90.] This information is now over a decade old. These data are
a harbinger, yet little impact from this study has been noted.

++++++++++++++++++++++


I am a sub-group member of a counterpart to your task group studying the
agricultural land application of sewer biosolids—, i.e., treated sewer
sludge. Accordingly, I wish to comment for the record. Although, I will be
speaking from my American experience, my main concern is more universal. The
subject deals with pathogens and, within that macrocosm of inquiry, the more
important issue is one of multi-drug resistant bacteria (MDRB).



There is a distinct lack of recognition for issues relating to multi-drug
resistant bacteria in land applied sewer sludge as well as biosolids. The
former term relates to essentially untreated sludge, the latter, i.e.,
biosolids—is composed of two separate levels of treatment—Class B and Class
A, with the second to contain virtually no detectable pathogens. The recent
report by the US National Academy of Sciences has not only called into
question the U.S. EPA Part 503 guidelines for land application of biosolids
but also more specifically indicated a need for the U.S. EPA to consider
MDRB.



In a recent meeting of our task-group, one of the members raised the
question relating to land application of composted biosolids. Composting
raises the level of manipulation of biosolids to that of a manufactured
product, often incorporating green-waste, i.e., trimmings from various forms
of vegetation. The essence of the question related to the survival of
pathogens, hence the underlying issue of surviving MDRB. The question went
something like this---"If Staphyloccus aureus (S.a.) were found dead, did
that mean that the problem was solved?" The corollary--- was it dead or
merely in the viable but non-culturable (VNC) state? (see below). Further,
this says nothing for uptake of released naked DNA.



Additionally, during the above noted meeting, I had mentioned that there is
now strong medical evidence that about ½ of the non-hospital but community
acquired skin infections in the Greater Los Angeles area are now MRSA. MRSA
stands for methicillin resistant Staphylococcus aureus.

Multi antibiotic-resistance happens because small lengths of DNA, called
transposons can carry a variety of antibiotic resistance or virulence genes,
are able to move from the bacterial chromosome to plasmid or to a virus DNA
(think phage) which can then be freely exchanged between bacteria.



Harmless gut and soil bacteria have become reservoirs for multi resistance
plasmids which may be gained from pathogens or where there are other
commensals that contained the shared genetic information.



For example, Levy found that the resistance in gut bacteria of cattle moved
to gut bacteria of mice having access to the same area, then from the mice
to pigs, chickens, and flys. He notes a Dutch study that followed bacteria
from animals to the human food chain and entered the consumer’s kitchen. In
other cited examples, he noted the distinct relationship between MDRB in
animals and thence to humans attending them, even though the humans used no
antibiotics or ate the animals. Levy’s work is not new. (Levy SB, MD. The
Antibiotic Paradox. New York, Plenum Press 1997).



Thus the current U.S. EPA Class B biosolids with its allowed fecal coliform
counts of 2 X10/6 per gram may actually constitute a large aliquot when
containing MDRB and applied to areas with animal or vector access. These
bacteria are thus able to colonize animals, including humans, through
ingestion. There are indications within the literature of E. coli O157:H7
being to travel up the vascular system in lettuce. Since lettuce is eaten
raw, the risk should be clear to most readers. Once ingested, the shiga
containing plasmids may be transferable to normal flora, thence later to
pathogenic bacteria found in humans or animals, making later treatment with
particular antibiotics ineffective. Additionally, one finds that there is a
remultiplication of bacterial numbers within standing sludge, biosolids or
compost (see Hassen below). Thus, the current Part 503 limits on biosolid
marker organisms may have little bearing on the ultimate numbers.

During composting, the mesophiles (these function at normal body
temperatures) can transfer genetic information to thermophiles (these
operate above the lethal fever temperatures). The archaea, which are extreme
thermophiles (these can take temperatures above the boiling point of water),
are recognized as a separate third domain of life together with the bacteria
and eucarya. Transfer of plasmids to bacteria from archaea, has been
demonstrated. Thus, in theory, it may be possible to develop a MDRB that can
survive temperatures found within composting.



Furthermore, there is experimental evidence that even when disrupted by
radiation, these ancient organisms can reassemble. This, from a theoretical
perspective, then raises questions of the eventual failure of
pasteurization.



Hassen, et al found that , gram-positive bacteria, especially micrococcus,
spores of bacilli, and fungal propagules survived, and reached high
concentrations in compost. Not only that, "the appearance of gram-negative
rods (opportunistic pathogens) during the cooling phase may represent a
serious risk for the sanitary quality of the finished product intended for
agronomic reuse." (Bioresour Technol 2001 Dec;80(3):217-25)



Methicillin was an anantibiotic developed in the late 1950s which was
effective in killing Staphylococcus aureus. The organism by that time had
already become resistant to penicillin G and to almost every other available
antibiotic. In the case of strain MRSA 16, only one effective antibiotic,
vancomycin, remains; it has serious side effects on humans and its armor has
been recently pierced. There is now vancomycin resistant S. a. This
resistance was acquired from genetic exchanges between enterococci and
Staph.



Staphylococcus aureus is easily transferred from the skin of one patient to
another and it can be fatal if it enters the bloodstream, or the site of a
surgical operation. Resistant strains are controlled with great difficulty.
Because of this, hospitals maintain stocks of vancomycin which had, until
lately, been considered as the 'drug of last resort'. The effective
treatment may now be amputation.



Enterococci are ubiquitous in sludge and wastewater. One strain of
Enterococcus is totally resistant to all antibiotics—including vancomycin.
Enterococci are also not easily killed by sewer processing (see below).
Although enterococci have historically had a relatively low virulence, the
situation has changed. Transfer of resistance genes to Staphylococcus aureus
from Enterococcus had been demonstrated in the laboratory and so it was only
a matter of time before this was to be seen in nature. In 1997, a strain of
MRSA resistant even to vancomycin was reported from Japan. This was shortly
followed in Belgium. Two months ago, it was found on the East Coast of the
U.S. Three vancomycin-intermediate Staphylococcus aureus (VISA) and four
hetero-VISA strains were detected. They emerged from strains that belonged
to locally endemic methicillin-resistant S. aureus (MRSA) genotypes. This is
a very worrisome development.



It was once thought that over-prescribing of antibiotics was the main route
for development of multi-drug resistant bacteria (MDRB). It is important to
remember that only about one half of all antibiotic use is through the
health care system. The remainder of the use is found in industrial or
agricultural settings---settings with considerably fewer controls. The
disposal of waste streams, whether from agriculture, industry, or urban
environments may ultimately flow through sewer treatment works.



This paper argues that wastewater treatment plants may now constitute the
principal and expanding source of MDRB.



Contrary to popular myth, many pathogens survive their passage through a
sewer treatment plant thus, remaining to constitute an increased public
health risk. That this situation has continued for some time may be
attributed, in part, to economics and the antiquated water quality
standards. Nonetheless, readily available scientific and medical literature
are, and have been for some time, replete with data demonstrating and
confirming this fact. Studies reported in the scientific and medical
literature date back to at least 1970 showing failure of treatment.



The reader is encouraged to review the results of the recent project
entitled Occurrence and Fate of Antibiotic Resistant Bacteria in Sewage. The
project was conducted at the Department of Veterinary Microbiology of the
Royal Veterinary and Agricultural University, which was supported by the
Danish Environmental Protection Agency. Again, it should be mentioned that
the European governments, as compared to the U.S., are the insurance
carriers for public health.



The issue at hand is multi-facetted. There is the continued development of
chlorine resistance in bacteria and this is synergistic with the development
of multi-drug-resistance in bacteria. Heavy metals often associated with
waste streams do augment multi-drug resistance and perhaps bacterial
virulence. Additionally, there are current indications of increasing beach
closures from high bacteria counts. This last issue raises some questions
that must be answered.



Further, as noted above, recent findings from the National Academy of
Science raise questions about the U.S. EPA’s Part 503 regulation of land
applied biosolids. The conclusion appears to be that land disposal of
biosolids, may have been carried out under questionable science. The issue
is not resolved and considering the worrisome acceleration of MDRB, the
situation warrants further review.



In a review of the literature, one notes that as far back as 1930s there
were credible papers discussing not only the survival of pathogens, but the
length of that survival. In one of the more recent studies, it was
demonstrated that enteric viral pathogens were able to remain viable in
estuarian mud for 13 years. Further, there are numerous reports of disease
outbreaks from marine shellfish contaminated with viral pathogens. Yet,
those shellfish had passed health tests using current health standards for
water quality.



Thus after their release pathogenic organisms and viruses do constitute a
long standing increased risk to not only man but the environment.
Additionally, one example of a more recent scientific curiosity is the
resuscitation of the recently found 250 million-year-old bacteria. It is
apparently well and comfortable in its modern laboratory environment.



With the advent of molecular biology and the subsequent advancements from
genetic engineering, we are beginning to understand that these pathogens are
"smart" and have numerous survival mechanisms available to them. After all,
they have been here for billions of years and in that time, have developed
wide based mechanisms for surviving many difficult situations. They not only
continue today, but thrive.



In the last two or three decades, the topic of drug resistant bacteria has
moved into increasing prominence in both scientific and lay media.
Antibiotic resistance appeared shortly after the development of antibiotics
in the late 1930s and early 1940s. However, the seriousness of this issue,
as relates to public health and water quality through multi-drug resistance,
is rapidly increasing. This accrues to the escalation of antibiotic use as
well as the formation and the transmission of antibiotic-resistant strains.
Antibiotics act by inhibiting either protein synthesis, cell wall
construction, or DNA replication in bacteria (Pharmaceutical Information
Associated, Ltd., 1994). A pathogen becomes resistant to an antibiotic used
to treat it either through mutation or through the acquisition of a plasmid
for resistance from another strain of bacteria (Neu, 1992). Resistant
pathogens render an antibiotic ineffective by either destroying or modifying
the antibiotic or preventing the antibiotic from recognizing or accessing
its target. We are now talking about multi-drug resistant bacteria, and on
top of that, what to do. To highlight the veracity of this, the following
abstract from a recent article published in SCIENCE is offered.



"Pathogenic enterococci are becoming resistant to currently available
antibiotics, including vancomycin, the drug of last resort for Gram-positive
infections. Enterococci pose a significant public health threat, not least
because of the risk of transferring vancomycin resistance to the ubiquitous
Staphylococcus aureus." (this is now history)



To accomplish this genetic transfer, bacteria have evolved small
transferable genetic information packets called plasmids. To provide some
analogy, think of copying a piece of software from a friend’s computer and
inserting it into your operating system. These bacterial plasmids facilitate
rapid and very broad dissemination of the drug resistant genetic information
amongst mixed bacteria. This information sharing and transfer is able to
cross species as well as genus barriers (DeFlaun & Levy 1989). Thus,
resistant enterococci selected in one environment can pass resistance genes
not only to other members of their own genus and species but also to other
organisms in other genera. This information can be shared with the cells of
plant root hairs. Interestingly, genetically manipulated plants often
contain bacterial resistance genetic information. Insects feeding on these
plants have been found to pick up this resistance in their gut bacteria. In
the case of honey bees, it is then not unreasonable to look for wideral
lateral transfer into the human food chain. The consequence may be transfer
to human gut flora.



Staphylococci share their plasmids with Listeria; E. coli can share genes
with other members of the Enterobacteriaceae as well as the pseudomonads and
Neisseria, just to mention a few. In fact, the same tetracycline resistance
determinants can be found among Gram-positive and Gram-negative bacteria as
well as in the mycobacterium (Roberts 1997). The genetic flexibility and
versatility of bacteria have therefore contributed largely to the efficiency
by which antibiotic resistance has spread among bacteria and among
environments globally.

Resistance genes reside not only in disease-causing organisms, but in the
common and previously non-pathogenic organisms as well. These formerly
harmless bacteria, such as E. coli or enterococcus, can now cause a fatal
illness in the young, old and in the immunocompromised. Moreover, these
bacteria harbor resistance genes which can spread to the bacterial strains
that do cause infection. These latter bacteria then constitute a "lending
library". Unfortunately, these reservoirs are not being examined by those
often charged with protecting the public health and welfare.



Another and less well understood mechanism for the transfer of multi-drug
resistant bacteria is found at the local sewer treatment plant. As bacteria
wind their way through these treatment processes, the selective pressures
against them increase. In consequence, there is a greater effort by bacteria
to pass on survival enhancing genetic information. Additionally, as the
environmental stresses increase, the bacteria up-regulate numerous other
survival mechanisms to assure that they and their genetic material survive.
These can include chlorine resistance.

In one of the several major studies looking at this, the scientists followed
bacteria through a sewer treatment works. Fecal coliforms were the test
organism. These bacteria were isolated at various locations in the plant as
the sewage was passing through the treatment process. They were isolated
from: a) the inlet, b) the primary sedimentation tank, c) the activated
sludge digestion tank, d) the final settling tank, e) the outlet and f) the
return activated sludge drain. They were then examined for multi-drug
antibiotic resistance. The study looked for the presence of drug resistant
plasmids. The scientists were able to distinguish resistant bacteria from
those still sensitive to antibiotics. Several drugs were tested and included
tetracycline, kanamycin, chloramphenicol and streptomycin, ampicillin,
nalidixic acid, rifampicin, and sulfisoxazole. We have seen above, the big
gun—vancomycin is now in trouble. A total of 900 separate tests were
conducted. Of these over half contained multi-drug resistant plasmids.



While this is interesting, there was a new finding that raised considerable
concern. The further along that the wastewater had progressed through the
treatment process the greater the tendency was development of multiresistant
strains. Additionally, the study demonstrated that these multi-resistant
bacteria also simultaneously carried, and then passed around their multiple
transferable drug-resistance plasmids. Thus, the take-home message is that
drug resistance and the transfer of multi-drug resistant occurs in
wastewater treatment plants. [Nippon Koshu Eisei Zasshi 1990
Feb;37(2):83-90.] This information is now over a decade old. These data are
a harbinger, yet little impact from this study has been noted.



Above, it was mentioned that the survival mechanisms were up-regulated as
the stresses increased. As an example, enterococcus will be discussed. It is
a common component of waste water, is highly resistant to treatment, is
rapidly gaining notoriety as a new multi-drug resistant pathogen, and a
large percentage of these organisms do survive treatment to be ultimately
released into the environment.



Enterococci, which have been known as a cause of infective endocarditis for
close to a century, more recently have been recognized as a cause of
nosocomial infection and "superinfection" in patients receiving
antimicrobial agents.



>From an environmental perspective, enterococcus is fascinating. It can
withstand severe conditions that will easily kill other enteric bacterial
pathogens (note here we are NOT yet discussing viruses). In the lab, one
sees this shift starting in about 4 hours. When one flushes the toilet, the
saline environment of the normal body fluids is rapidly mixed with the fresh
water environment. This abrupt shock and shift of environment in which
enterococcus finds itself causes the bacteria to switch on protective
survival mechanisms.



Keep in mind that, in a medium sized town, it takes about 2.5 hours for the
city’s sewage effluent to enter the treatment plant where it stays exposed
to that environment; then is ultimately sent to the ocean or down river to
the next city’s intake. When introduced into a fresh water environment
enterococcus shifts to a survival mode and this mode renders it much more
resistant to normal sanitary controls.



The survival state is called "viable but nonculturable" (VNC), and this
renders it essentially invisible to laboratory methods relying on plate
count. This leads to false-negative results for purposes of water quality
(or biosolid) monitoring by agencies relying on plate counts. Thus in these
instances, there is the chance of missing highly resistant strains that then
become major pathogens and which can, as we have seen, defy most
antibiotics. In its VNC state, for example it can take extremely high saline
waters, and in the lab can withstand a sodium chloride (NaCl) solution of
6.5% (seawater is 3.5%--and this is close to your internal body fluid). It
is unaffected by higher chlorine levels, up to 0.05% which is considerably
higher than that needed to maintain residual fresh water sanitation, and
also a pH down to 3.3. It is not readily killed by standard antibiotics and
has developed resistant strains that defy vancomycin and other lesser
materials. In the VNC mode it is insensitive to chloramphenicol.
Additionally, it grows at 45 degrees C (115 F), which is well above the
lethal fever temperature for man. It can survive 60degrees C (140 F), which
is well above the required sludge cooking temperatures (98 F) used by many
sewer plants for sludge digestion. Additionally, there are indications of
developing chlorine resistance.



In the VNC state, the bacteria when plated may actually die, thus giving a
false impression of its status. This death is caused by a lack of internally
generated antioxidants to overcome the peroxides and other reactive oxygen
species. In animals, we see this as reperfusion injury.

Thus in the VNC state enterococcus can withstand severe environmental
insults, and survive when in bottom mud at the outfall or estuarian mud.
Thus, it is able to survive for extended periods. This survival in estuarian
mud may see it later flushed into the ocean during early rains.

One would expect that the likelihood of survival for enterococcus to be
accompanied similarly mechanisms in enteric viruses, some of which are
extremely resistant to current sanitary controls. The viral particles also
have very long survival rates in estuarian mud. Thus, it is possible that a
"witches brew" flushes from the mud with the first rains.



Such survival, then begs the issue of pathogen survival in sludge or
biosolids applied to the land. This then warrants further critical analyses.
Is there is reason to suspect that survival of pathogenic organisms in sewer
effluent is different from survival in sludge? Thus in soil applied sludge
or biosolids, if there is much topographic relief, these pathogens may move
with the surface or soil water to streams.



In America, under the Clean Water Act’s Phase II NPDES permits (U.S.
controls and permitting requirements) for storm water and return flows,
setbacks and slopes need further consideration. Stream set back limits may
require reanalysis when considering MDRB. This may show to be of critical
importance when compared to the former rational that did not consider the
transfer of MDR genetic information to non-pathogens, thence to the
environment.



There are sufficient studies in the literature tying viral and bacterial
pathogen counts to community rates of infection and then following these
through treatment works and streams to the near-shore marine environment. As
to its impact on ground water, there are numerous studies demonstrating
contamination by pathogens from spread sewage. From this one needs to tease
out the studies that discuss biosolids as differentiated from sludge. Again,
this begs the question of other pollutants reaching the ground water.
Additionally, many of the aging and failing trunk lines leading to sewer
plants are, and have been for years, leaking into the groundwater beneath
many towns and cities across America.



As the mission environmental and health officer for the USAID Mission to
Somalia, I had first hand experience with this. The aquifer under the
capital became so polluted that a new well field was required some miles
from the city.



Again, we may use enterococcus as an example. From a clinical and
pathophysiological perspective, we have previously demonstrated that
enterococcus is important. Approximately 20% of bacterial endocarditis is
attributed to this organism. It is, however, not necessarily seen until it
reaches an acute state, often when there has been valvular damage in the
heart. This may necessitate valve replacement surgery—assuming one is
actually a surgical candidate. Some people can not tolerate surgery and thus
must attempt to live with the defect. The organism may lie clinically silent
producing a smoldering subclinical level of disease. Thus, the 20% figure
for bacterial endocarditis may actually be an understatement. Those most
affected are the immunocompromised, elderly, and those with barrier
disruptions to the skin or mucosal membranes. In the last case it may be
merely from beach sand scratching the skin at the waist line of bathing
suits or under wet suites, or swallowing contaminated water.



To conclude, the following thought is a paraphrased excerpted statement by
the WHO’s chief of Communicable Disease, David Heymann, before the US Senate
hearing on The Spread of Communicable Disease, in 2001.



Some microbes have accumulated resistant genes to virtually all currently
available drugs. Thus, these have the potential to cause untreatable
infections. Accordingly, such diseases may have no effective cures over the
next 10 years unless there is some uncharacteristic breakthrough in drug
therapy. Therefore, if current trends continue, many important medical and
surgical procedures, including cancer therapy, bone marrow and organ
transplant, hip and knee replacement, and perhaps coronary bypass surgery
could no longer be undertaken without undue risk of unstoppable infection.

++++++++++++++++++++++





To: Members of Canadian Committee Antibiotic Resistance

To: World Health Organization



Fm: Edward McGowan, Ph.D., BSc Medicine



Re: Additional thoughts to consider when combating antimicrobial resistance



The CIDS was kind enough to send sent me reprint copies of the Nov/Dec 2000
Canadian Journal of Infectious Diseases, in which there is a discussion of
controlling antimicrobial resistance. We have completed a brief review of
the situation here and it was accordingly suggested that I copy you on the
following thoughts.



In the main, emphasis on combating antimicrobial resistance has been applied
to practioners and agrifood interests.



While from a logical perspective, the above approach will bear longer-term
reward, there seems to have been a neglected area warranting near-term
attention.



A less well understood mechanism for the transfer of multi-drug resistant
bacteria is found at the local sewer treatment plant. As bacteria wind their
way through these treatment processes, the selective pressures against them
increase. In consequence, there is a greater effort by bacteria to pass on
survival enhancing genetic information. Additionally, as the environmental
stresses increase, the bacteria up-regulate numerous other survival
mechanisms to assure that they and their genetic material survive. These can
include chlorine resistance.

In one of the several studies looking at this, the scientists followed
bacteria through a sewer treatment works. Fecal coliforms were the test
organism. These bacteria were isolated at various locations in the plant as
the sewage was passing through the treatment process. They were isolated
from: a) the inlet, b) the primary sedimentation tank, c) the activated
sludge digestion tank, d) the final settling tank, e) the outlet, and, f)
the return activated sludge drain. They were then examined for multi-drug
antibiotic resistance. The study looked for the presence of drug resistant
plasmids.



The scientists were able to distinguish resistant bacteria from those still
sensitive to antibiotics. Several drugs were tested and included
tetracycline, kanamycin, chloramphenicol and streptomycin, ampicillin,
nalidixic acid, rifampicin, and sulfisoxazole. We have seen that the big
gun—vancomycin is now in trouble. A total of 900 separate tests were
conducted. Of these over half contained multi-drug resistant plasmids.



While this is interesting, there was a new finding that raised considerable
concern. The further along that the wastewater had progressed through the
treatment process the greater the tendency was development of
multi-resistant strains. Additionally, the study demonstrated that these
multi-resistant bacteria also simultaneously carried, and then passed around
their multiple transferable drug-resistance plasmids. Thus, the take-home
message is that drug resistance and the transfer of multi-drug resistant
occurs in wastewater treatment plants. [Nippon Koshu Eisei Zasshi 1990
Feb;37(2):83-90.] This information is now over a decade old. These data are
a harbinger, yet little impact from this study has been noted.



Additionally, there are the aging and failing effluent conduits—the sewer
mains and laterals. Thus, part of the issue in any urban area is leaking
from underground sewer mains. In many of the older cities, there has been
little or no repair or maintenance of these underground conduits. Thus,
there is probably severe leakage to the surroundings.



In Santa Barbara (my hometown—although I spend considerable time in
Victoria, BC—which I suspect has similar issues---as well as my wife’s
hometown of London) many of the sewer trunks are over 100 years old,
cracking and crumbling. This lost effluent is thought to be partly
responsible for the numerous beach closures---actually, Santa Barbara has
the highest number of beach closures in the U.S.



The paper that follows suggests that sewer effluent arising from hospitals
may play a particularly serious role in furthering contamination. Centers
dealing with the very sick, the very old, and the immuno-compromised are
generally regarded as centers for the development and perpetuation of drug
resistant pathogens. These centers also utilize vast amounts of chemo-
therapeutic agents and other materials that may foster increased resistance.
Their untreated discharge to the local sewer system is thus a concern, and
your organization may be interested.  If the sewer mains are leaking, then
this merely increases the potential risk for materials reaching the
environment, aquifer, rivers, or beach and ocean.













HOSPITALS: DURING THEIR RECONSTRUCTION AND MODIFICATION---SOME THOUGHTS FOR
THE DESIGNERS



Hospitals may represent epicenters for the formation of drug resistance.



As a member of the Biosolid-Subgroup of a Multi-Jurisdictional Solid Waste
Task Group, I wish to bring to your attention items warranting consideration
during the design of a new hospital or the addition to a hospital. The
subject deals with water and pathogens and, within that macrocosm of
inquiry, the more important issue is one of multi-drug resistant bacteria
(MDRB).



Hospitals and Multi Drug Resistant Bacteria.



In the revamping of any hospital, serious thought should be applied to the
make-up of sewer effluents. In many industrial settings, there is a
requirement for pre-treatment. This requirement accrues to the need to
protect receiving waters, hence the health of humans and the environment.
Accordingly, hospitals should be considered within the category of
industrial wastewater generators.



Amongst the community at large, including staff at sewer treatment works,
there is a distinct lack of recognition for issues relating to MDRB. These
organisms pass from sink or toilet through sewer treatment to the
environment at large. Although current water quality standards are silent on
such issues, there is a pressing need for recognition. Thus hospitals, as
major members of a community, and for the ultimate needs of their patient
base, need to go beyond current standards.



Contrary to popular myth, many pathogens survive their passage through a
sewer treatment plant thus, remaining to constitute an increased public
health risk. That this situation has continued for some time may be
attributed, in part, to economics and the antiquated water quality
standards. Nonetheless, readily available scientific and medical literature
are, and have been for some time, replete with data demonstrating and
confirming this fact. Studies reported in the scientific and medical
literature dating back to at least the 1970s show failure of treatment.
Thus, this is hardly new knowledge. [Fontaine, et al, (1976); Grabow,  et
al. , (1973); Linton, et al., (1974); Walter et al,. (1985)].



Previous studies have shown that waste effluents from hospitals contain
higher levels of antibiotic-resistant enteric bacteria than waste effluents
derived from other sources [1,2,3,4,5,6].



In a recent meeting of our task-group, one of the members raised the
question relating the survival of pathogens once the material had left the
sewer treatment works. The essence of the question is related to the
survival of genetic material. Hence, analyses on the underlying issue of
surviving MDRB. The question went something like this---“If Staphyloccus
aureus were found dead, did that mean that the problem was solved?” The
corollary--- was it dead or merely in the viable but non-culturable (VNC)
state, a starvation arrested state, or killed from a starvation but
otherwise recoverable state by sudden nutrient excess in the culture?
Additionally, there are issues of the re-uptake of naked DNA.



Recently, in discussing mobile genetic elements (MGE), Nielsen, et. al.
[7,8], demonstrated that DNA was well protected in dead cells and that
transforming activity remained. The survival of such material was found to
be up to two years [9]. Additionally, these papers demonstrate that growing
plants, via their roots, could transfer MGEs to bacteria. The reverse has
also been widely demonstrated. Thus, non-pathogens and non-bacteria can
serve as reservoirs for maintaining resistance.



Pneumococci, for example, can take-up naked DNA from the environment
(natural transformation from lysed bacteria). Thus merely finding “dead”
bacteria may be no assurance that risk has reached acceptable levels.
Further, from the classical work of Griffith, we know that pathogens can
regain virulence from dead bacteria.



Additionally, during the above noted meeting, I had mentioned some notes
taken during a recent medical grand rounds. The speaker, an expert on
infectious disease, indicated that there is strong medical evidence that
about one-half of the general, non-hospital community acquired skin
infections in the Greater Los Angeles area are now MRSA. The April 2003,
issue of Skin & Allergy News also had a front-page article on this since
dermatologists often stand on the front lines.



Prior to 1985, vancomycin resistance in human pathogens had not been
described in the literature. A decade later, more than one-half of the
hospitals in New Jersey contained strains of vancomycin resistant bacteria.
By the end of 1998, one quarter of enterococci isolated from intensive care
units across the U.S. expressed resistance to vancomycin.



Recent publications in the medical literature discuss the cost of drug
resistant bacteria. The annual cost in the U.S. was estimated to be upwards
of $30 billion annually (Dominguez EA, et al. Infection Control & Hospital
Epidemiology, vol 21,#1, supp, Jan 2000, p S4).



It was assumed for a long time that gene transfer between different species
of microorganisms is a very rare event at best; that view has changed.  The
available evidence suggests that interspecific transfer of genes has
occurred between the three major groups of organisms: archaebacteria,
eubacteria and eukaryotes. There is very strong evidence that gene transfer
easily occurs between distantly related bacteria. Marcinek, et al [10]
estimated that under the natural conditions of a sewer treatment works,
between 106 to 109 gene transfer events between different E. faecalis
strains should take place per day. The maximum number of transfer events for
the sex pheromone plasmids between different strains of E. faecalis in the
municipal sewage water treatment plant was found to range from 10(5) to
10(8) events per 4 hour period. This work also indicated that gene transfer
should take place under natural conditions following release of sewer
effluent.



Iversen, et al, [11] isolated VRE in 21 of 35 untreated sewage samples
(60%), from 5 of 14 hospital sewage samples (36%), from 6 of 32 treated
sewage samples (19%), and from 1 of 37 surface water samples. It was
speculated that antimicrobial drugs or chemicals released into the sewage
system sustained VRE in the system. Others [5] have demonstrated direct
evidence that related tetracycline resistance-encoding plasmids have
disseminated between different Aeromonas spp. and E. coli and between the
human and aquaculture environments in distinct geographical locations.
Collectively, these findings provide evidence to support the hypothesis that
the aquaculture and human compartments of the environment behave as a single
interactive niche.



Ribeiro [12] and others [13] have found that as these organisms progress
further through sewer treatment, the level of resistance and number of
transferred plasmids increases. Reinthaler et al [14] found that the highest
resistance rates were found in E. coli strains of a sewage treatment plant
which treats not only municipal sewage but also sewage from a hospital.
Thus, these authors concluded that sewage treatment processes contribute to
the dissemination of resistant bacteria in the environment.



One of the issues being studied locally is the leaking of sewer system trunk
mains that underlie many American cities. There has been a sufficiency of
studies to raise questions about exfiltration—the loss of sewer effluent
from these sewer mains. That rising ground water actually enters these older
mains and systems is now well beyond question. The issue is one of logic. If
rising ground water gets in through failing joints, cracks, and breaks, what
keeps sewer water from utilizing these same portals when the surrounding
ground water falls below them?



Cenci, et al [15] reviewed the incidence and the patterns of the antibiotic
and metal resistance in 106 strains of Escherichia coli isolated from ground
waters, used also as drinking water supply. These organisms were studied in
comparison with the resistance behavior in the 104 strains of the same
microorganism isolated from non hospitalized patients. When, however, these
were compared to hospitalized patients, the patterns of the antibiotic
multiresistances and the strains isolated from patients and from ground
waters did not differ greatly. The authors concluded that their findings
strengthened the hypothesis that resistance to antibiotics had been acquired
by Escherichia coli strains before reaching the ground waters.



If the above has any validity, then what of the possible effects of
different pharmaceutical groups such as anti-tumour drugs, antibiotics and
contrast media as well as Absorbable organically bound halogens (AOX)
resulting from hospitals effluent input into sewage? Recently, the
occurrence and fate of pharmaceutically active compounds (PhACs) in the
aquatic environment was recognized as one of the emerging issues in
environmental chemistry and as a matter of public concern [16]. Residues of
PhACs have been found as contaminants in sewage, surface, and ground- and
drinking water samples. Again this begs the issue of leaking sewer mains and
a need for pretreatment.



Most antibiotics and their metabolites are excreted by humans after
administration and therefore reach the municipal sewage with the excretions.
Kummerer, et al [17] looked at a worst case scenario on found concentrations
of the antibiotics in hospital effluents. These concentrations were
estimated and compared with minimum inhibitory concentrations for
susceptible pathogenic bacteria and with the genotoxic potency. Both the
concentrations calculated for hospital effluents and the adverse effects in
bacteria were in the same order of magnitude.



Absorbable organically bound halogens (AOX) are mostly persistent in the
environment, and accumulate in the food web. One important source of AOX in
hospital effluents may be x-ray contrast media containing an iodine carbon
bond. These materials may also add to selection pressures and development of
resistant strains.



Others [18] have noted that the mere process of chlorinating effluent tends
not only to increase resistance, but also increase the competitive edge of
these survivors. Thus, we are now seeing developing resistance to chlorine,
other antiseptics, and disinfectants. This raises some interesting academic
as well as practical questions at the cellular and molecular level. For
example, would developing resistance to chlorine also affect the efficacy of
hypochlorite released within lysosomes, there by reducing effectiveness of
leukocytes?



The workers at sewer plants are also at risk. Several papers [19,20,21] have
reported on transfer of viral particles and bacteria in aerosols that are
generated by and surround many of these plants.  In addition, there are
studies on wind drift of these plumes into the surrounding neighborhoods.







Citations


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