The overuse of antibiotics

By Haoyu Li

Since the discovery of penicillin by Sir Alexander Fleming in 1928, new technology has been continuing to advance, such as genetic modification, which allowed us to mass produce all kinds of antibiotics and never are antibiotics in shortage. This allowed modern medicine to develop rapidly with even the most complicated surgeries able to take place without the worry of infection. Doctors started giving people antibiotics for even the most unnoticeable fever (Blazer, 2015).

In 2008, this changed, as the UK regulated the use of antibiotics and suggested that antibiotics must be prescribed, and pharmacies are not allowed to sell antibiotics without a prescription (Wellsteed, 2015). However, discovered in 2017, several online stores had been selling antibiotics without looking at prescriptions and without a license, and as a result were closed (Boyd et al, 2017). Antibiotics stopped being available to the public to self-medicate in the UK.

Currently, these restrictions are only in the UK. Other countries, such as China and the US, have barely limited their use. Although, in 2015, the National Health Office of China published a document (Zhong et al, 2015) in order to regulate the use of antibiotics under clinical settings, it only restrains the doctors to a certain extent because the regulations in the document are very suggestive. For example, the document states that “usually” the doctor should not prescribe antibiotics to patients with a minor infection and what is meant by “usually” case is very opinion based. Moreover, this document does not specify anything to do with the selling of antibiotics in pharmacies, which is the biggest source of antibiotics when people self-medicate. Although the tablet form of all antibiotics is prescribed, ointment and spray forms of antibiotics can be easily purchased online at substantially low costs. The self-medication problem has become so common that some doctors will very easily give patients antibiotics knowing that even if they do not, the patient can still get a hold of antibiotics themselves, whether it is through previous unfinished courses or an alternative illegal source of little legislative consequences. 

The use of antibiotics in agriculture is even more concerning. Farmers have discovered that using antibiotics will cause their livestock to have an increase in both muscle and fat build up, which essentially means more profit per animal.  Also, the animals are less likely to die through an infection and each farmhouse will have more capacity (Blazer, 2015). However, what is unrealized is that the same antibiotics are being used as medicinal antibiotics since we all face the same pathogens, and this has led to the increase of prevalence of resistance of bacteria in both the farmer and the animals. 

In the 2006 NARMS (National Antibiotic Resistance Monitoring System) report, chicken breast was collected through random purchase. 97.7%tested positive for E. coli, and 82.6% for Enterococcus, which, for both bacteria isolates showed resistance to one or more drugs (Rosenblatt-Farrell, 2009). Even though it is suggested the antibiotics loses its activity after being cooked, active antibiotics that are only allowed to be used in poultry was found in the urine samples of 1500 children in the Zhejiang Province of China (Fu, 2015). Despite, the inhibiting impact of quinolones (an antibiotic not allowed to be used on children but discovered therefore must have been obtained from livestock) on bone development, these antibiotics changes the microbiota in the large intestine to be more resistant and the exact impact of this is still to be discussed. 

Although most people understand the situation of antibiotics overuse, it is commonly underestimated how easily antibiotics can enter the environment via many different ways, which potentially could change the whole microbiota where the average prevalence of resistance increases (Martinez, 2009). 

Firstly, majority of the public does not dispose out of date antibiotics properly. An anonymous survey in the US showed that more than 50% of people have admitted flushing antibiotics down the toilet and only 22.9% had returned it to the pharmacy (Rosenblatt-Farrell, 2009). In addition to this, pharmaceutical factories are another source of antibiotics entering the environment. The following quote by Meghan Hessenauer is cited in the work of Rosenblatt-Farrell (2009): 

Guidelines for pharmaceutical manufacturing wastes are geared towards the discharge of chemicals used in the process rather than active pharmaceutical ingredients. There is no regulation and no limits on antibiotics themselves.

Although most factories put the best management practice in place, drugs are still making their way out of the factories. In a study by Li et al (2010), downstream and effluent samples showed significantly high levels of resistance for almost all the antibiotics tested for compared to upstream samples. 

Secondly, Antibiotics are also entering the environment through excretion of animals using it. In other words, humans and their livestock. Up to 80% of amoxicillin may be excreted by urine unaltered and still in their active form (Rosenblatt-Farrell, 2009). It has also been suggested that ceftriaxone and ceftazidime can be excreted through sweat (Hoiby et al, 2000) and it may have contributed to the selection of MRSA, a well-known pathogenic bacterium which exists within the skin flora. In livestock, up to 75% of tetracycline administered to swine was excreted unaltered (Chee-Sanford et al, 2001). Unlike human waste that goes down the sewage, these excreted drugs can persist in the environment and create the opportunity for resistance selection (Martinez, 2009). In addition to this, the way animal wastes are handled also contributes to the spread of antibiotics, for example farmers would spread the waste of animals on the soil surface as a fertilizer, which could contaminate the soil and the surface or ground water. The use of waste lagoons also provides an alternative route for birds and insects to pick up the antibiotic resistant bacteria (Rosenblatt-Farrell, 2009). 

To sum up, we haven’t discovered a new line of antibiotics since the 1970s, and with the overuse phenomenon discussed above, much higher than normal concentrations of antibiotics are present in the ecosystem, accounting for extreme selective pressure towards resistance traits among wild strain bacteria. Soon enough, we will run out of viable options to treat ‘Superbugs’. Therefore, despite all the conveniences antibiotics have brought to modern medicine, their use has to be strictly monitored and limited.

References:

Blazer, M. (2015). Missing Microbes: How the Overuse of Antibiotics Is Fueling Our Modern Plagues. New York: Picador.

Boyd, S. et al (2017). Obtaining antibiotics online from within the UK: a cross-sectional study. Journal of Antimicrobial Chemotherapy, 72(5), pp.1521-1528.

Chee-Sanford, J. et al (2001). Occurrence and Diversity of Tetracycline Resistance Genes in Lagoons and Groundwater Underlying Two Swine Production Facilities. APPLIED AND ENVIRONMENTAL MICROBIOLOGY. 67(4). pp. 1494-1502

Fu, Z. (2015). Urine sample of children in Zhejiang Province shows traces of antibiotics. China Medical News. 2015(8). 6-6.

Hoiby, N. et al (2000). Excretion of β-Lactam Antibiotics in Sweat—a Neglected Mechanism for Development of Antibiotic Resistance? ANTIMICROBIAL AGENTS AND CHEMOTHERAPY. 44(10). pp. 2855-2857

Li, D. (2010). Antibiotic Resistance Characteristics of Environmental Bacteria from an Oxytetracycline Production Wastewater Treatment Plant and the Receiving River. Appl Environ Microbiol. 2010 Jun; 76(11): 3444–3451.

Martinez, J. (2009). The Role of Natural Environments in the Evolution of Resistance Traits in Pathogenic Bacteria. Biological Sciences. 276(1667). pp. 2521-2530.

Rosenblatt-Farrell, N. (2009). The landscape of antibiotic resistance. Environ Health Perspect. 2009;117(6): A244-A250.

Wellsteed, S. (2015). The Health and Social Care Act 2008 Code of Practice of the prevention and control of infections and related guidance. Viewed 22/08/2020. <http://www.suttonccg.nhs.uk/Documents/Code_of_practice_280715_acc.pdf>. 

Zhong, N. et al (2015). Guidelines for the clinical application of antibacterial drugs. Viewed 22/08/2020. <https://wenku.baidu.com/view/e55a0e85336c1eb91a375df4.html>.