Friday, August 30, 2019

Microscope parts well explained (compound microscope)

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Parts of the microscope
Historians credit the invention of the compound microscope to the Dutch spectacle maker, Zacharias Janssen, around the year 1590.   The compound microscope uses lenses and light to enlarge the image and is also called an optical or light microscope (vs./ an electron microscope).  The simplest optical microscope is the magnifying glass and is good to about ten times (10X) magnification.  The compound microscope has two systems of lenses for greater magnification, 1) the ocular, or eyepiece lens that one looks into and 2) the objective lens, or the lens closest to the object.
Parts of the microscope

Basic parts of the microscope:

Eyepiece Lens:  the lens at the top that you look through.  They are usually 10X or 15X power.

Tube:  Connects the eyepiece to the objective lenses

Arm:  Supports the tube and connects it to the base

Base:  The bottom of the microscope, used for support

Illuminator:  A steady light source used in place of a mirror.  If your microscope has a mirror, it is used to reflect light from an external light source up through the bottom of the stage.

Stage:  The flat platform where you place your slides.  Stage clips hold the slides in place.  If your microscope has a mechanical stage, you will be able to move the slide around by turning two knobs.  One moves it left and right, the other moves it up and down.

Revolving Nosepiece or Turret:  This is the part that holds two or more objective lenses and can be rotated to easily change power.

Objective Lenses:  Usually you will find 3 or 4 objective lenses on a microscope.  They almost always consist of 4X, 10X, 40X and 100X powers.  When coupled with a 10X (most common) eyepiece lens, we get total magnifications of 40X (4X times 10X), 100X , 400X and 1000X.  To have good resolution at 1000X, you will need a relatively sophisticated microscope with an Abbe condenser.

Rack Stop:  This is an adjustment that determines how close the objective lens can get to the slide.  It is set at the factory and keeps students from cranking the high power objective lens down into the slide and breaking things.  You would only need to adjust this if you were using very thin slides and you weren't able to focus on the specimen at high power.

Condenser Lens:  The purpose of the condenser lens is to focus the light onto the specimen.  Condenser lenses are most useful at the highest powers (400X and above).  Microscopes with in stage condenser lenses render a sharper image than those with no lens (at 400X).  I

Diaphragm or Iris:  Many microscopes have a rotating disk under the stage.  This diaphragm has different sized holes and is used to vary the intensity and size of the cone of light that is projected upward into the slide.  There is no set rule regarding which setting to use for a particular power.   Rather, the setting is a function of the transparency of the specimen, the degree of contrast you desire and the particular objective lens in use.

Uganda confirmed another case of Ebola virus

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KAMPALA -Uganda reported another case of Ebola on Thursday, a nine-year-old girl who had crossed the border from neighbouring Democratic Republic of Congo, where the haemorrhagic disease has killed at least 1,800 in a year-long outbreak.
The health ministry said the girl, of Congolese origin, was identified by a screening team at Mpondwe border post as she tried to cross to Uganda with her mother on Aug. 28.
The girl exhibited symptoms including high fever, body weakness, rash and unexplained mouth bleeding, according to the statement.
A sample of her blood tested positive for Ebola, the ministry said. “Since the child was identified at the Point of Entry, there are no contacts in Uganda,” it said.
The new case is likely to heighten fears of the outbreak spilling over from Congo into neighbouring countries.
In June, two people who had travelled from Congo died in Uganda while a third who was part of the same visiting family died after he was sent back home.
Uganda has previously suffered multiple outbreaks of Ebola but fatalities have been kept low in part because of quick diagnoses and a rapid response mechanism.
In the statement the ministry said a rapid response team had been dispatched to Kasese district, some 470 km (290 miles) from the capital Kampala, to help with “case management, community engagement, contact tracing, psychological support and vaccination.”

Friday, August 23, 2019

Air pollution kills, even when it meets air quality guidelines



Even when air pollution is at levels below air quality guidelines and regulatory limits, it can still pose a hazard to public health, a new study finds.


In a 30-year analysis of 652 cities in 24 countries and regions on six continents, researchers found that increases in air pollution were linked to increases in related deaths. The study, published Wednesday in the New England Journal of Medicine, was one of the largest international studies to look at the short-term impact of pollution as a cause of death, the researchers said.

The analysis of air pollution data from 1986 through 2015 found there were increases in total deaths linked to exposure to inhalable particles and fine particles. The deaths were from cardiovascular and respiratory problems.

Particle pollution is the mix of solid and liquid droplets in the air, according to the US Environmental Protection Agency. It can come in the form of dirt, dust, soot or smoke. It comes from coal- and natural gas-fired plants, cars, agriculture, unpaved roads and construction sites.

With higher levels of pollution, the faster people are dying, said Chris Griffiths, a professor of primary care at Queen Mary University of London.

"These are avoidable deaths. Most concerning is that deaths relating to pollution occur at levels below international recommended pollution limits," Griffiths told Science Media Centre. "The authors provide the strongest evidence yet that target air pollution levels are set too high."



Health effects of air pollution


A study in July found that long-term exposure to air pollution, especially ground-level ozone, is like smoking about a pack of cigarettes a day for many years and can cause problems such as emphysema. Another study found that it can cause COPD and age lungs faster. Air pollution also increases the risk of heart disease, stroke and lung cancer.

Earlier studies predicted exposure to ground-level ozone concentrations could lead to millions more acute respiratory problems and would cost the United States billions of dollars. Exposure to air pollution caused more than 107,000 premature deaths in the United States in 2011 alone, research has found.

Under the Trump administration, pollution guidelines have gotten looser. The administration's recent guidance to states would allow a state to emit 43% more pollution across state lines than before, even though the agency itself said it could result in 1,400 more premature deaths by 2030 than the Obama-era plan it is replacing. States have asked the federal courts to block the administration's overhaul of these rules.

President Donald Trump has said that it's been a "top priority" to make sure "America has among the very cleanest air and cleanest water on the planet," but since he has been in office, the number of "unhealthy air days" has increased, according to the Environmental Protection Agency. "Unhealthy air days" occur when the level of ozone or particulate matter is high enough to be a danger to kids, the elderly or people with lung problems.

That may in part be related to the administration's roll back of dozens of environmental protections. Trump has also moved to freeze vehicle emission standards and pull out of the international Paris climate agreement. After years of decline, US carbon emissions have risen sharply, according to 2018 data. Carbon emissions are the main driver of climate change.

Monday, August 19, 2019

why cesarean kids are immunocompromised?


Humans are born germ-free. Yet, birth is normally the time when vitally important bacteria start to colonise the body including the gut, skin and lungs. Researchers have long suspected that this early colonisation sets the course for one's later health. It could be, however, that a caesarean section prevents certain bacteria, ordinarily interacting with the baby's immune system, from being passed on from the mother to the new-born. Paul Wilmes, head of the Eco-Systems Biology research group at the LCSB, and his colleagues have now found the first evidence of this in a study of new-borns -- half of whom were delivered by caesarean section. Wilmes reports: "We find specific bacterial substances that stimulate the immune system in vaginally born babies. In contrast, the immune stimulation in caesarean children is much lower either because the bacterial triggers are present at much lower levels or other bacterial substances hamper these initial immune reactions to happen."

This bacterial coloniser-immune system link -- together with other factors -- could explain why caesarean section babies are statistically more prone to develop allergies, chronic inflammatory diseases and metabolic diseases. "It could be that the immune system of these children is set on a different path early on," suggests Paul Wilmes. "We now want to further investigate this link mechanistically and find ways by which we might replace the lacking maternal bacterial strains in caesarean-born babies, e.g. by administering probiotics."

"Of course, it is already clear that we should not intervene too strongly in the birth process. Babies should only be delivered by caesarean section when it is medically necessary," Paul Wilmes stresses. "We need to be aware that, in doing so, we are apparently intervening massively in the natural interactions between humans and bacteria."

Saturday, August 10, 2019

How soon can pregnancy be detected?


Pregnancy tests are most reliable from the first day of your missed period, although some tests can be used as early as 4 or 5 days before your period is due.

Check the packaging of your test to find out when it can be used.

If you have regular periods, you'll probably know when your next period is due.
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Is weed safe for pregnant lady?


If you're not sure, it's a good idea to wait at least 3 weeks after you think you may have conceived before doing a test.

Read more about doing a pregnancy test.

Pregnancy test results

A positive test (pregnant) result is almost certainly correct. A negative (not pregnant) result is less reliable.

If you still think you're pregnant after a negative result, wait a few days and try again.

If you keep getting negative results, but you're worried about your period being late, speak to your GP.

For more information, see How accurate are home pregnancy tests?


READ ABOUT:salt pregnancy test


When did I conceive?

Pregnancy tests check for the presence of the pregnancy hormone, human chorionic gonadotrophin (HCG), in your urine. Your body begins to produce HCG after you conceive.

If you get a positive test result on the first day of your missed period, it's probably about 2 weeks since you conceived.

You can use the pregnancy due date calculator to work out when your baby is due.

More sensitive tests may be able to confirm that you're pregnant from as early as around 8 days after conception.

Some pregnancy tests can give an estimation of when you might have conceived based on the level of HCG in your urine.

Thursday, August 8, 2019

Is weed safe for pregnant lady?

CHICAGO – Pregnancy started out rough for Leslie Siu. Morning sickness and migraines had her reeling and barely able to function at a demanding New York marketing job, so like rising numbers of U.S. mothers-to-be, she turned to marijuana.
“l was finally able to get out from under my work desk,” said Siu, who later started her own pot company and says her daughter, now 4, is thriving.
There’s no proof that cannabis can relieve morning sickness, and mainstream medicine advises against use in pregnancy because of studies suggesting it might cause premature birth, low birthweight and infant brain deficits.
But the National Institute on Drug Abuse is pressing for more solid evidence. Many of those studies were in animals or complicated by marijuana users’ other habits and lifestyles.
“I don’t want us to cry wolf,” said Dr. Nora Volkow, the agency’s director. “We have to do these studies in a way that can identify risks.”
Use has almost doubled: Sharp uptick in pregnant women using marijuana during a key time in baby's development

Seeking answers

With nearly $200,000 from her agency, University of Washington scientists in Seattle are seeking clearer answers in a new study investigating potential effects on infants’ brains. The agency is supporting three similar studies in other states.
In Seattle, they’re enrolling pregnant women during their first trimester who are already using marijuana for morning sickness. Researchers don’t provide the pot, and the use of other drugs, tobacco and alcohol isn’t allowed. Infants will undergo brain scans at 6 months and will be compared with babies whose mothers didn’t use marijuana while pregnant.
For government and university authorities, it’s worthy research that takes advantage of a booming trend. Recent data show the number of pregnant U.S. pot users has doubled since 2002, with 7% reporting recent use and higher rates in some states.

read about:Natural birth control method using the moon beads.

But some opponents of recreational marijuana who think the science is settled have complained to the university and the federal government, calling it bogus research that endorses drug use and needlessly endangers fetuses.
The criticism underscores the challenges of investigating how drugs of any kind affect pregnant women and their offspring.
“There are so many reasons NOT to study drugs – particularly fear of causing birth defects. But the results would be no studies of the drugs’ efficacy during pregnancy, or the risks to the fetus,” said Dr. John Lantos, director of pediatric bioethics at Children’s Mercy hospital in Kansas City, Missouri. “It’s risky to do studies of potentially risky drugs but it’s risky not to do studies.”

Doctor says it's 'not worth the risk': More pregnant women are using marijuana, study finds
Among the most tragic examples is thalidomide, a drug developed in Germany in the 1950s as a sedative. It was later widely promoted and prescribed to treat morning sickness, mostly in western Europe and Canada, despite a lack of research in pregnant women. It soon became linked with severe birth defects and was removed from most markets by the early 1960s.
The U.S. Food and Drug Administration never approved thalidomide for morning sickness because of safety concerns. The agency has approved a synthetic version of THC, the part of marijuana that causes a high, for AIDS-related appetite loss and a similar drug for nausea caused by cancer drugs, but has not approved it for morning sickness.
Scientist Natalia Kleinhans is leading the University of Washington’s study, aiming to recruit 35 pregnant marijuana users and 35 pregnant women who didn’t use pot.
The pot users are asked to buy from licensed dealers and photograph it so researchers can calculate the THC and CBD, another compound that doesn’t cause a high. Participants are paid $300 but can quit using anytime and remain in the study.
Medical and recreational marijuana are legal in Washington state, and Kleinhans says women who use it for morning sickness are different from pregnant pot users in years past, who often did other drugs, smoked or drank.
“They’re making a choice that people might not agree with. But it’s not out of desperation. It’s an informed choice,” said Kleinhans, a brain imaging specialist who studies the brain and behavior.
Are guilty of making it? Millennials consider this their top financial mistake

What opponents are saying

Study opponents contend that researchers are recruiting marijuana addicts, that payment encourages participants to keep using, that women aren’t being adequately informed of risks, and that babies will be harmed by being tested. Researchers say MRI brain scans are safe and that infants will be tested while sleeping so won’t need potentially risky sedatives.
While more than 30 states have legalized marijuana for medical and/or recreational use, opponents also note that the federal government still considers pot an illegal drug – a stance that scientists say has hampered research.
Dr. Pat Marmion, an OB-GYN in southern Washington, says he helped coordinate efforts to file complaints with the university and the U.S. Department of Health and Human Services, which oversees the National Institutes of Health. An HHS spokesperson declined comment.
“We should be encouraging women who are pregnant to not use marijuana instead of incentivizing them to continue,” Marmion said.
Under U.S. law, research that involves humans must be approved by review boards to make sure participants’ rights and safety are protected.
Karen Moe, director of the university’s human subjects division, said authorities there investigated the critics’ concerns and concluded that most were unfounded. But she said they agreed to provide a handout on possible risks from marijuana use in pregnancy, not just links to similar information online, and also reworded recruitment materials to clarify that participants could quit using marijuana and still receive full payment.
“From our standpoint the situation is essentially resolved and the study is good to go,” Moe said.
Dr. Mishka Terplan, a member of the American College of Obstetricians and Gynecologists’ addiction expert group, said that for years, the thalidomide scare “shut down all research of medications in pregnancy.” Not enough is known even about medications commonly prescribed for morning sickness, he said.
“We shouldn’t assume that because we classify something as illegal that it is shameful,” Terplan said. “And that because something is legal and prescribed, it’s helpful.”

read about:The causes and complications of menorrhagia and how to stop or treat heavy menstrual bleeding.

The National Institute on Drug Abuse is providing almost $1.5 million for three similar studies of marijuana use in pregnancy – at Washington University in St. Louis, at the University of Denver and at Kaiser Permanente in Northern California.
“One of the big arguments about why this is unethical is that we already know the answers. That is not true,” said Susan Weiss, who oversees outside research for the institute. “We’re living in this very large social experiment and we need to learn from it.”
Leslie Siu, the businesswoman who used marijuana while pregnant, now lives in Denver, where pot is legal, and sells a marijuana-based spray. Siu said marijuana deserves to be studied “so we can get the right answers.”
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

Wednesday, August 7, 2019

Could drones deliver better health service!!!


Drones are the sexy, mysterious tech craze that are often a butt of a joke, a vague solution or an ominous threat. But no matter how flashy, good technology should still solve concrete problems. Amid the hype of getting packages and pizzas delivered in half the time, what if drones could revolutionize transportation networks, connecting people to what they actually need the most?

The health of a community relies on efficient networks. Medicine and medical supplies need to be transported reliably from Point A to Point B. This, in turn, relies on roads to travel on. Sturdy roads, able to endure heavy rains and bad weather, are something many in developed countries take for granted. But worldwide, a staggering one billion people lack access to all-season roads. What that means for people who live in remote villages: a simple rainstorm can turn a dirt road into a muddy and impassable mess, cutting them off from vital goods, services and medicines.

A surprising new technology might make a difference. Andreas Raptopoulos (watch his TED Talk) and Paola Santana co-founded Matternet, a company that adds smart software to nimble drones. Their signature product, Matternet ONE, can carry 1 kilogram of cargo over 15-20 kilometers on a single battery charge.

Matternet has worked with WHO in Bhutan to deliver medical supplies to remote hospitals, and with MSF (Doctors Without Borders) in Papua New Guinea to transport medical tests for tuberculosis.

In March 2016, Matternet started tests, along with UNICEF, in Malawi to see how well drones could deliver medical tests and blood samples from remote villages to labs. They’re working with the Malawian government to see if the drones could reduce the wait times for HIV test results, specifically for infants.


An estimated one million people in Malawi live with the disease, as of 2014. Testing — and regular medication — is crucial to survival, and yet it takes an average of 11 days to deliver supplies from health centers to labs and eight weeks to return test results. Also, according to Raptopoulos, “More than three-quarters of them are within 20 kilometers of each other or a diagnostic lab.” Using drones could dramatically speed up this process and solve the problem of distance.

The first step to solving a problem is assessing what’s already happening. Paola Santana, who is also the Head of Network Operations and Lead Coordinator for this project, studied Malawi’s current system for transporting HIV tests. “There is someone on a motorcycle or in a car that does a circuit every day. They need to go and select the number of labs where they start in the morning, and by the afternoon, they have picked up all of these samples from these clinics. Then they go to the hospital where these samples are going to be analyzed,” she says. The problem is, though, that these routes are outdated. “These circuits have been created based on data that has been there for a while. So imagine that as populations shift, more people now live in other areas that are not being served every day. Still, the logistics circuit stays the same.”

Logistics, she says, need to account for how people are moving, how outbreaks are spreading and how many samples are transported in real time. That way, a regular and efficient system is created, one that can transport tests once a day, as opposed to once a week or even twice a month, which is the current norm.


With this data, Santana and her team clearly understood the task at hand. “The challenge is trying to envision how the system should work that has nothing to do with how the system works today. How do we adapt the flow of logistics to a new technology?”

Working with Malawi’s Ministry of Health, Department of Civil Aviation and Ministry of Transportation, among others, Matternet first mapped the geography of the approved flying area. Then, they entered the data into the software so that any obstacles could be accounted for in determining the safest and most effective routes.

Through the app, a user can select the landing location and command the drone to take off. Because it flies at around 400 feet, a user can also track its course on the app and get a notification when it lands.

This means that in the future, lab technicians could autonomously use the app to send HIV tests from their remote villages to central hospitals, and get the results back in a timely manner.


Santana and her team were in Lilongwe, Malawi, for a total of two weeks. During the first half of the trip, they worked from 8am to 5pm every day to acclimate the drones to the new geography and make sure they could fly safely over densely populated areas. “The goal was to collect diagnostics from Area 25 Health Center and Area 18 Health Center to the Kamuzu Central Hospital to be analyzed,” Santana says.

As they prepped, Matternet, UNICEF and Malawi’s Ministry of Information hosted hands-on sessions and a Community Demo Day so that the locals could see how the drones work and learn what they’d be carrying. These demos also stressed the importance of HIV awareness, getting tested and taking antiretrovirals.

The next week, they conducted the first official test launch. The drone completed a 10-kilometer journey from Area 25 Health Center to Kamuzu Central Hospital, a journey UNICEF calls the “first known use of UAVs [unmanned aerial vehicles] on the continent for improvement of HIV services.”


Malawi’s Minister of Health, Peter Kumpalume, praised the launch as a huge step forward in the country’s fight against HIV/AIDS. “We are at the forefront of technology. The countdown to ending HIV/Aids has begun and today is another step forward in meeting that goal.”

UNICEF’s Malawi representative, Mahimbo Mdoe, also remarked on the implications for transportation in the country. “HIV is still a barrier to development in Malawi. This innovation could be the breakthrough in overcoming transport challenges and associated delays experienced by health workers in remote areas of Malawi.”

Monday, August 5, 2019

Eastern equine encephalitis


Image result for equine encephalitis

Eastern equine encephalitis is a viral illness that is transmitted to people and horses through the bite of an infected mosquito. The virus is an alphavirus and is closely related to western equine encephalitis and Venezuelan equine encephalitis viruses


Most people infected with this virus will not develop any symptoms. Symptoms of illness may include a sudden onset of fever, chills, and muscle or joint aches. Cases with severe illness may begin with fever, headache, and vomiting that may progress into disorientation, seizures, and coma.
Eastern equine encephalitis is the most severe mosquitoborne disease ,Approximately one in three persons who develop severe illness die. Most of those who survive will have permanent neurologic damage.
There is no treatment for eastern equine encephalitis. Hospitalization and supportive care may be needed.
 Eastern equine encephalitis virus is maintained in a cycle involving Culiseta melanura mosquitoes and birds. This mosquito is commonly found in tamarack bogs or hardwood swamps and feeds almost exclusively on birds. People become infected with this virus by other mosquito species that create a “bridge” between infected birds and mammals. Common human-biting mosquito species such  as Aedesvexans and Coquillettidia perturbans 

                   Diagnosis  

  • Blood tests. Someone who is infected with EEE will have an increased level of antibodies in their blood. Antibodies are proteins produced by the immune system that attack foreign substances such as viruses and bacteria. Increased levels of antibodies are a sign that your immune system is fighting the virus.  
  • CT scan produces detailed, cross-sectional images of the brain. The results from a CT scan can rule out other possible diseases that may be causing inflammation.
  • Magnetic resonance imaging (MRI) is another procedure that takes detailed X-ray images of the brain to help detect brain inflammation.
  • lumbar puncture (spinal tap) may be used to take a small sample of cerebral spinal fluid to determine if a child has EEE or other problems.
  • An electroencephalogram (EEG) can be used to detect small seizures in the brain that may not be obvious from watching the person. An EEG works by recording the brain's continuous electrical activity using stickers attached to the scalp that measure electrical activity.
  • needle biopsy may be used to take a sample of brain tissue to determine the underlying cause of the inflammation.

                      Treatment  

Although there is no specific treatment for Eastern Equine Encephalitis (EEE), there are several things that can be done to help manage the symptoms of the disease:
  • Anticonvulsants for seizures
  • Respirator for breathing problems
  • Pain relievers for headache, fever or body ache
  • Sedatives for irritability or restlessness
  • Corticosteroids for brain swelling
                          Preventive measures
The best way to prevent eastern equine encephalitis is to protect yourself and your family from mosquito bites:
  • Avoid outdoor activities at dusk and dawn, the peak feeding time for many mosquitoes, particularly from July through September.
  • Use repellents containing DEET according to label directions – up to 30% DEET is safe and effective for adults and children over two months of age.  Other effective repellents include picaridin, IR3535, and oil of lemon eucalyptus. Only use products that are registered by the Environmental Protection Agency.
  • Pre-treat clothing and gear with permethrin-based products.
  • Wear loose-fitting, long sleeved shirts and pants.
  • Keep mosquitoes out of your home by maintaining screens on windows and doors.

Did you know!? antibacterial resistance existed before people start using drugs to kill bacteria

Image result for antibacterial resistance
Imagine a world where your odds of surviving minor surgery were one to three. A world in which a visit to the dentist could spell disaster. This is the world into which your great-grandmother was born. And if humanity loses the fight against antibiotic resistance, this is a world your grandchildren may well end up revisiting.
Antibiotics changed the world in more ways than one. They made surgery routine and childbirth safer. Intensive farming was born. For decades, antibiotics have effectively killed or stopped the growth of disease-causing bacteria. Yet it was always clear that this would be a rough fight. Bacteria breed fast, and that means that they adapt rapidly. The emergence of antibiotic resistance was predicted by none other than Sir Alexander Fleming, the discoverer of penicillin, less than a year after the first batch of penicillin was mass produced.
Yet, contrary to popular belief, antibiotic resistance did not evolve recently, or in response to our use and misuse of antibiotics in humans and animals. Antibiotic resistance first evolved millions of years ago, and in the most mundane of places.
I am a bioinformatician, and my lab studies the evolution of bacterial genomes. With antibiotic resistance becoming a major threat, I’m trying to figure out how resistance to antibiotics emerges and spreads among bacterial populations.

A billion-years-old arms race

Most antibiotics are naturally produced by bacteria living in soil. They produce these deadly chemical compounds to fend off competing species. Yet, in the long game that is evolution, competing species are unlikely to sit idly by. Any mutant capable of tolerating a minimal quantity of the antibiotic will have a survival advantage and will be selected for – over generations this will produce organisms that are highly resistant.
So it’s a foregone conclusion that antibiotic resistance, for any antibiotic researchers might ever discover, is likely already out there. Yet people keep talking about the evolution of antibiotic resistance as a recent phenomenon. Why?
Resistance can and does evolve when bacteria are persistently exposed to a new antibiotic they have never encountered. Let’s call this the old-fashioned evolutionary road. Second, when bacteria are exposed to a novel antibiotic and are in contact with bacteria already resistant to this antibiotic, it is just a matter of time before they get cozy and trade genes. And, importantly, once genes have been packaged for trading, they become easier and easier to share. Bacteria then meet other bacteria, which meet more bacteria, until one of them eventually meets you.
Bacteria can evolve resistance to high levels of antibiotics in just days.

The rise and fall of sulfa drugs

For all their might, antibiotics are not the only substances capable of effectively killing bacteria (without killing us). A decade before the mass production of penicillin, sulfonamide drugs became the first commercial antibacterial agent. Sulfa drugs act by blocking an enzyme – called DHPS – that is essential for bacteria to grow and multiply.
Sulfa drugs are not antibiotics. No known organism produces them. They are chemotherapeutic agents synthesized by humans. No natural producer means no billion-year-old arms race and no pool of ancient resistance genes. We would expect bacteria to evolve resistance to sulfa drugs via the good old-fashioned way. And they did.
Just a few years after their commercial introduction, the first cases of resistance to sulfa drugs were reported. Mutations to the bacterial DHPS enzyme made sulfa drugs ineffective. Then penicillin and the antibiotic era came about. Sulfa drugs were relegated to a secondary role in medicine, but they gained popularity as cheap antimicrobials in animal husbandry. By the 1980s resistance to sulfa drugs was rampant and worldwide. What had happened?

At odds with resistance

To answer this question our research team took sequences of sulfa drug resistance genes from disease-causing bacteria and compared them to millions of “normal” versions of the DHPS enzyme in nonpathogenic bacteria.
The team identified two large groups of bacteria that had DHPS enzymes resistant to sulfa drugs. By studying their DNA sequences, we were able to show that these resistant DHPS enzymes had been present in these two groups of bacteria for at least 500 million years. Yet sulfa drugs were first synthesized in the 1910s. How could resistance be around 500 million years ago? And how did these resistance genes find their way into the disease-causing bacteria plaguing hospitals worldwide?
The clues left in gene sequences are too fuzzy to conclusively answer the latter, but we can certainly speculate. The bacteria we identified as harboring these ancient sulfa drug resistance genes are all soil and freshwater bacteria that thrive under the well-irrigated subsoil of farms. And farmers have been adding huge amounts of sulfa drugs to animal feed for the past 50 years.
The sublethal concentrations of sulfa drugs in the soil are the perfect setting for resistance genes to be transferred from these ancient resistant bacterial populations to other bacteria. All it takes is for one lucky bacterium to meet one of these ancient resistant ones in the subsoil. They trade some genes, one bacterium to the next, and resistance spreads until a newly minted resistant bacterium eventually makes it to the groundwater supply you drink from. You do the math.

Nothing new under the sun

As for why sulfa drug resistance genes would be around 500 million years ago, there are two plausible explanations. On the one hand, it could be that 500 million years ago there was a bacterium that synthesized sulfa drugs, which would explain the evolution of resistance. However, the lack of remnants from such a biosynthetic pathway makes this unlikely.
On the other hand, resistant bacteria may have been around just by chance. The argument here is that there are so many bacteria, and such diversity, that chances are that some of them are going to be resistant to anything scientists come up with. This is a sobering thought.
Then again, this is already the baseline for antibiotics. Like climate change, antibiotic resistance is one of those problems that always seem to be a couple decades away. And it may well be. A turning point for me in the climate change debate was a decade-old opinion piece in New Scientist. It stated that we should make every possible effort to prevent climate change, especially in the unlikely case that it was not caused by man, because that would mean that all we can do is palliate a natural phenomenon.
Our research points in the same direction. If resistance is already out there, drug development can offer only temporary relief. The challenge then is not to quell resistance, but to avoid its spread. It is a big challenge, but not an insurmountable one. Not feeding wonder drugs to pigs would do nicely, for starters.

Sunday, August 4, 2019

Wonderful plans to stop superbugs (resistant bacteria).

Antibiotic resistance is here to stay, but that doesn’t mean we can’t do anything to stop it.
A headline that always catches my attention is that antibiotic resistance is on the rise. Underlying these headlines is that the disease-causing bacteria that make us sick are becoming less responsive to treatment by our most common antibiotics. If you read past the headline, you will see that the World Health Organization (WHO) predicts that by the year 2050, there will be 10 million deaths annually from antibiotic resistant bacteria (ARB). This would place ARB ahead of cancer as a leading cause of death worldwide. Those headlines assume that the world cannot do anything to intervene.
I am a physician scientist trained in infectious diseases who has had a front row seat as ARB has been on the rise. I am also a member of a group of researchers who are developing bacteriophages – viruses that kill bacteria – as alternatives to antibiotics as an additional means to limit ARB in the U.S. and worldwide.
To understand why ARB is approaching crisis levels, it is important to understand the limitations of the antibiotics and what trends are contributing to it.

Antibiotic development has its limitations

People have used antibiotics to treat infections since the early 1940s, but naturally produced antibiotics are millions of years old. These medicines are derived from natural products that bacteria and fungi use to combat other bacteria. They use these products to eliminate their competition.
Most of the antibiotics produced by industry have one thing in common: they work the same way. They block the bacteria’s ability to make proteins, DNA, RNA or even its cell wall, the consequences of which are deadly to the bacteria. Thus most new antibiotics are not based on new ways to kill bacteria; they’re simply incremental improvements.
The consequence is that when a bacterium develops immunity to one of these antibiotics, it often gains resistance to that entire antibiotic group. Simply put, a single resistance event can cause us to lose quite a few antibiotics that had previously been effective against that bacterium.
Here are five ways to kill bacteria. Designua/Shutterstock.com

Antibiotic resistance might be right under your nose

Much of the ARB problem is caused by humans. Bacteria often become resistant to antibiotics after exposure to these drugs. The easiest way to think about this concept is, “What can grow, will grow!” You’ve got a body full of microorganisms - called your microbiome - that includes an estimated 38 trillion bacteria. While the antibiotic you take kills the bacterium making you sick, it also kills many of those other good bacteria that are harmless. That leaves you with a microbiome populated by many bacteria that are resistant to not just that single antibiotic, but often that entire group. Because only ARB can grow in this environment, your microbiome becomes populated largely with ARB. Thus, even healthy people who have taken antibiotics in the past may harbor ARB.
The problem gets even worse when you consider all the unnecessary antibiotic use across the worldDoctors use antibiotics in people with viral infections even though they don’t work. Livestock producers feed them to animals to accelerate growth and provide health advantages. More than 70% of all antibiotic use globally is in animals, and you can also be exposed to antibiotics just by handling and consuming meats from animals raised on antibiotics. All these exposures contribute to growing global antimicrobial resistance.
If we know the root causes of antimicrobial resistance, then why is it still occurring? It may seem like physicians and scientists have been sitting and watching this all happen. That’s not correct.

We are not unified

Hospitals in the U.S. are taking steps to limit ARB. For some patients, everyone who comes in contact with them must wear gown and gloves. This practice limits the spread of ARB throughout the hospital. Another control is preventing overuse of our most powerful antibiotics to curb the evolution of ARB. Usually, you have to call an infectious diseases physician like me to get access to these drugs. These two basic components of antibiotic stewardship have been quite effective in limiting ARB.
We still see ARB because not every hospital adheres strictly to these practices, and enforcement of antimicrobial stewardship in hospitals is not uniform.
Amplifying the problem is that some hospitals don’t routinely screen patients for antibiotic resistant microbes. There are patients who carry ARB in their microbiomes and it’s pretty difficult to block the spread if you don’t know who carries them.
These strategies together can limit ARB in a single hospital, a part of town, or even an entire city. But you may still be losing the battle across your state. So what can our leaders do to limit ARB?
In Norway, a decrease in the use of antibiotics and strict routines has led to fewer cases of MRSA (Methicillin-resistant Staphylococcus aureus), a virulent drug-resistant infection. AP Photo/Torbjorn Gronning

How to reduce antibiotic resistance?

The bottom line is that an alternative to antibiotics must be developed. A new industry has emerged that focuses on using viruses to kill bacteria, but these efforts have been inconsistent.
Bacteriophages have been used successfully in a few recent cases to treat ARB. A patient with a severe skin, liver, and lung infection and a man with a life-threatening ARB were both treated successfully with bacteriophages, providing great hope for the future of phage therapy.
However, these cases provide only anecdotal evidence that such therapies can work. They are far from meeting the rigorous standards of efficacy the FDA applies to antibiotics. The government must encourage high quality, reproducible studies supporting the use of these antimicrobial agents to further our understanding of their potential in the treatment of ARB in the larger population.
The U.S. also needs to invest in the development of antibiotics that attack bacteria in novel ways. The government must have a policy of incentives to entice industry to attack this problem because market forces don’t favor huge investments in antibiotic development. The reason is most patients use an antibiotic once every few years for a couple of weeks at a time to treat infections. Compare that to a heart medication that patients must use daily for the rest of their lives; the latter is clearly more lucrative.
Other strategies the U.S. could adopt include uniform screening and antibiotic stewardship practices across its hospitals. Physicians may not like a governing body intervening in their practices, but the U.S. must reduce unnecessary antibiotic prescriptions. And the U.S. must limit antibiotics in livestock. This could have a huge impact.
Finally, once the U.S. implements these efforts, it must export them to the rest of the world. Executing these changes in the U.S. alone won’t reverse this trend; but if we’re serious about altering the trajectory ARB and developing antibiotic alternatives, all options must be on the table.