Project Inspiration and Description

Inspiration

During this season, our team wants to do an antibiotics-related project. In the very beginning of this season, we have heard the news about the discovery of resistant bacteria in West Lake sediment in Hangzhou. The idea grew out of our concerns about the dangers caused by “superbugs”, which is resistant to the majority of known antibiotics. Antibiotic resistance is a naturally occurring phenomenon, bacteria adapt to some drugs and become resistant that makes previously standard treatments for bacterial infections less effective, and in some cases, ineffective^[1]. According to the Centers for Disease Control and Prevention (CDC), about 23,000 American people die as a direct result of superbugs infections every year ^[2]. Except for antibiotics overusing, living or working at in unsanitary conditions with antibiotic residues also attribute to the spread of antibiotic-resistant bacteria. In response to this problem, people need to think about relevant solutions urgently. And our project arises at the historic moment.

Background

During past seventy years, antimicrobial agents, which used to treat infections caused by bacteria, has reduced morbidity and mortality of human beings and obviously prolong human’s life span. In other industries, antibiotics are extensively used for animal farming and agricultural purposes as therapeutic or asprophylactic agents^[4,5]. However, antibiotics used in human and veterinary medicine occasionally enter the environment via hospital effluents, agricultural waste, waste water treatment plant effluents and leakage from waste-storage containers and landfills^[6], those antibiotics reach natural systems and induce more antibiotic- resistant bacteria, which have significant effects on health care and agriculture industries through the food chain.

Credit: the U.S. Centers for Disease Control and Prevention

Our Project

Because of our concern about antibiotic-resistant bacteria and antibiotic pollution, we decided to make a brilliant plan to detect and degrade a kind of antibiotics. The first one we thought of was β-lactams as it is the most widely-used antibiotics, and also one of the antibiotic pollutions in environment. β-lactams work by inhibiting the bacteria’s cell wall synthesis and finally results in cytolysis or death due to osmotic pressure. The first discovered antimicrobial compound was penicillin. As time goes on, several new type of β-lactams ( from the original penicillin to penicillin derivatives, cephalosporins, carbapenems and monobactams) have been developed in order to deal with new β-lactam-resistant bacteria^[7].

In order to remove unnecessary β-lactams from water, we designed two novel system to detect and degrade β-lactams. The mec gene pathway from Staphylococcus aureus and the β-lactamase blaCMY-10 in Enterobacter aerogenes were designed as our β-lactams detective and degradative system respectively, which were transformed into E. coli during project process. The results of antibiotics detection illustrated that it can be sensitive to low concentration of ampicillin. And the zone of inhibition test showed that blaCMY10 can effectively degrade ampicillin, cephalothin and cefoxitin which is consistent with what we expected.

Application and Goals

Those exciting results encouraged us to create a combined device for application. For this purpose, we did a lot of interviews outside of the laboratories to collect different ideas and advices from all works of life. Based on the views from scholars and experts we visited, we find that our device should be installed at some places where exist antibiotic residues like waste water treatment facilities, hospitals and farms. We also got a important information from Pharmacist Jin: the β-Lactams’ half life period is last for 2-3 days,which means our device should detect and degrade β-Lactams efficiently in early time. As the result, our efforts should be made to devise methods to improve the degradation of β-Lactams once they reach natural environments. We propose that the ideal place to intall our applied device is drainage outlet at the place we list above. Apart from that, the biosafty is another important thing in our project both inside and outside of the laboratories. Since we need to put the β-lactams detective system into the devices, a important thing we should do is to stop release.

We've been fight with antibiotic-resistant bacteria for several years, but now we utilize their biological mechanisms (the antibiotic-resistant gene pathway and enzyme ) to reduce antibiotic pollution in environment in order to slow down their pace of change. Actually, some waste water treatment plants aren't designed to fully remove antibiotics^[8], it is important to create more new methods to reduce unnecessary antibiotics and antibiotic residues. In this aspect, our efforts provide a new view for antibiotics treatment in wastewater.

Reference

1. James M. , Steckelberg, M.D.,(2018).What are superbugs, and how can I protect myself from infection?. [online] Available at https://www.mayoclinic.org/diseases-conditions/infectious-diseases/expert-answers/superbugs/faq-20129283 (accessed 10/10/2019)

2. Miller K.,(2015)Superbugs: What They Are and How You Get Them.[online] Available at https://www.webmd.com/a-to-z-guides/news/20150417/superbugs-what-they-are#1 (accessed 10/10/2019)

3. José L. Martínez. Antibiotics and Antibiotic Resistance Genes in Natural Environments[J]. Science, 321.

4. Roberts M C , Stefan S , Aarts H J M . Erratum: Acquired antibiotic resistance genes: an overview[J]. Frontiers in Microbiology, 2012, 3.

5. Martinez J L. Environmental pollution by antibiotics and by antibiotic resistance determinants[J]. Environmental Pollution, 2009, 157(11):2893-2902.

6. Tello A , Austin B , Telfer T C . Selective Pressure of Antibiotic Pollution on Bacteria of Importance to Public Health[J]. Environmental Health Perspectives, 2012, 120(8):1100-1106.

7. Tamma PD, RodriguezBano J. The Use of Noncarbapenem β-Lactams for the Treatment of Extended-Spectrum β-Lactamase Infections.[J]. Clinical Infectious Diseases：an Official Publication of the Infectious Diseases Society of America, 2017, 64(7):972.

8. Roose-Amsaleg C, Laverman A M. Do antibiotics have environmental side-effects? Impact of synthetic antibiotics on biogeochemical processes[J]. Environmental Science & Pollution Research, 2016, 23(5):4000-4012.