scanning electron micrograph of superbug MRSA surrounded by cellular debris

Current Trends in Antibiotic Resistance

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"Bug resistant to all antibiotics kills woman"

The above headline was taken from BBC News, 1/13/2017.

In January 2017, a medical news story was published that went largely unnoticed by the public. A Nevada woman who had been traveling in India contracted a bone infection that could not be treated by 26 different antibiotics, including colistin, the very-last-resort antibiotic for this particular type of infection. The superbug breached all currently existing defenses, and the woman died of the infection.

How could this happen? And what does it mean for us?

Background Story

In August 2016, a woman in her 70s was rushed to the hospital in Wahoe County in Reno, Nevada. She had a severe infection originating from her right hip and femur bone, which was rapidly spreading throughout her body. Two years ago, she had fractured her right femur while traveling in India. She was hospitalized several times while in India and developed osteomyelitis in the injured bone.

Doctors found that she was infected with a carbapenem-resistant Enterobacteriaceae (CRE), a group of the most dangerous multi-drug-resistant superbugs which experts have called "nightmare bacteria". CREs are resistant to carbapenem, the drug of last resort for many multi-drug-resistant bacteria, because they have evolved to produce a mechanism of resistance called carbapenemase which disables the drug's effectiveness. The particular strain of bacteria isolated from this woman was analyzed and found to harbor a specific enzyme, New Delhi metallo-beta-lactamase-1 (NDM-1), which conferred broad spectrum antibiotic resistance to this superbug.

The bug was resistant to 26 different antibiotics including colistin, a rarely used drug saved solely to combat this type of bacteria – an ultimate last resort. No antibiotics available in the US were found to be effective, and the woman died of septic shock in September 2016.

scanning electron micrograph of CRE superbug resisting a human neutrophil, a bacteria-eating cell                                                               CRE. Source

Current Trends in Antibiotic Resistance

Cases of infection with CRE are on the rise, both in the world and in the US. Around 75% of infections occur in hospital or long-term care facility settings – settings where antibiotic usage is higher and thus bacteria have more opportunity to acquire modes of resistance. About 50% of CRE cases end in death. This is a grave concern, as there have been no new types of antibiotics produced since the 1980s to replace the current line of carbapenems and other final-resort drugs. 

Medical news from the past two decades highlight the presence of CRE and other multi-drug-resistant superbugs in our communities. In the United States, CRE cases went from 1.2% in 2001 to 4.2% in 2011 of all Enterobacteriaceae infections. The most common type of CRE in the United States is called Klebsiella pneumoniae carbapenemase, or KPC. The first case of KPC infection in the United States was reported in 2001 in North Carolina; since then KPC superbugs have been found in 41 states as well as worldwide. Israel reported a nationwide increase of KPC infections starting in 2006. Because KPC bacteria are a subset of CRE, they are resistant to carbapenems and virtually every other antibiotic. Death rates due to KPC infection have been reported as high as 44%.

In 2014, a number of patients at UCLA Ronald Reagan Medical Center and Cedars-Sinai Hospitals contracted infections with CRE. The source was linked back to the usage of faulty duodenoscopes, long optical tubes used to examine the inside of the small intestine. The duodenoscopes, which were impossible to completely sterlize, carried the superbug from infected person to person.

In November 2015, a new strain of E.coli was reported in China to be resistant to colistin. The new strain of bacteria was found in pig livestock, pork meat, and a small number of humans. Colistin is an older antibiotic; because of its side effects of kidney toxicity, other antibiotics have mostly replaced it in general usage. As a result, colistin is still effective on many antibiotic-resistant bacteria. However, China has been using colistin in their livestock for decades in order to speed up livestock growth, but which has bred resistance to the drug in animals. In 2016, the Chinese government approved the usage of colistin in hospitals, which only raised fears that more pan-resistant superbugs would appear. 

The new strain of E. coli owes its robust resistance to a gene that scientists have named mcr-1. To make things worse, mcr-1 is found on the plasmid, a portable piece of DNA inside all bacteria that allows them to exchange genetic material with one another. Since the 2015 report, the mcr-1 gene has been indentified in human samples in Malaysia, China, England, and Denmark. In 2016, the mcr-1 gene showed up in the United States for the first time in a Pennsylvania patient.

The first appearance of the enzyme NDM-1 was in a Swedish patient of Indian origin. He had traveled to New Delhi in 2008 and was hospitalized there for several illnesses. While in the hospital, he acquired a urinary tract infection caused by a strain of Klebsiella pneumoniae that could not be treated by the last-resort carbapenems. As more cases of carbapenem-resistant infections continued to appear around the world, a study at a Mumbai hospital in 2010 found that most of the bacteria isolated from these cases contained NDM-1. To date, bacteria containing NDM-1 have been isolated from humans in India, Pakistan, the United Kingdom, the United States, Canada, and Japan.

doctors performing blood test on patient in hospital at risk for antibiotic resistance arising

                                                                                       Source

What Needs to be Done Now

Antibiotic resistance is slowly but surely spreading throughout the globe. Our hospitals and long-term care facilities are the most vulnerable to the emergence of superbug epidemics. Therefore, it is critical for all of us to take action using the methods available to us to minimize the risk of further resistance.

  • We need to listen to our doctors when they tell us that we don't need antibiotics. Doctors are trained and experienced in providing nuanced treatment for ill patients. Their treatment plan for you already takes into account the risk of antibiotic resistance. A good doctor will only prescribe antibiotics for you when it is reasonably necessary.
  • We should follow all antibiotic treatment plans exactly as they are prescribed. It is extremely important to take the correct dosage and amount of medicine for the correct amount of days. 
  • We need to practice good hygiene. Specifically, we should take all necessary precautions when handling raw meat, eggs, and other animal products.
  • We need to lend our support to research and development of new types of antibiotics or improvements in existing ones. Furthermore, certain complementary therapies to antibiotics are currently under investigation, such as phage therapy or neutralization of resistant bacteria with aspergillomarasmine A. Therapies like these could open up entirely new avenues of treatment for us, if they are given the proper funding, approval, and attention.
  • We need to petition our government to approve policies that lower the risk of antibiotic resistance, such as discontinuation of the usage of colistin in livestock.
  • We need to spread the word and be purveyors of good knowledge regarding antibiotic resistance. The more conversation we engage in, the greater our awareness of the issue will be.
  • Finally, we need brave and committed people to execute constructive and original ideas for dealing decisively with antibiotic resistance. To any entrepreneurs reading this article: opportunity is pounding at the door here – answer it!

Featured Photo: Source // All opinions are my own.

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