Advances in Combating Antibiotic Resistance

The discovery of the first antibiotic, penicillin, by Alexander Fleming in 1928 was a medical breakthrough, allowing patients to recover from infections that had previously been killed. Since then, numerous antibiotics with diverse chemical structures have been developed and widely used to combat bacterial infections. 

Antibiotics continue to be an invaluable tool in the fight against bacterial infection. However, there are rising concerns that bacteria are once again gaining the upper hand as more and more strains of bacteria develop resistance to even the most powerful of antibiotics.  

A rapid change in antibiotic prescribing practice and usage, along with the development of novel antibacterial treatment strategies are required to reverse this worrying trend. 

The value of antibiotics

The human body has a highly effective immune system that tracks down harmful invading bacteria and destroys them before they have a chance to multiply and cause symptoms. Left unchecked, bacteria can develop vast colonies and cause serious damage throughout the body. Even when symptoms do occur, the immune system will usually fight off the infection and the body will recover from the attack. 

However, in some cases, the extent of the bacterial infection may overwhelm the immune system, and this is where antibiotics play an important role. They help to weaken or kill the invading bacteria, minimizing the harm they can inflict on the body. 

Antibiotics are particularly important for people who are more susceptible to infection, such as those with a compromised immune system, complicated wounds, or severe burns. In addition, antibiotics provide a valuable means of preventing infection when the body is made vulnerable to bacterial attacks during invasive medical procedures. 

Indeed, surgical site infection is the most common, and most costly, healthcare-associated infection1, and can lead to life-threatening postoperative complications. This is particularly true during procedures involving the implantation of medical devices, which can promote the development of biofilms that are associated with poor clinical outcomes². 

Based on a review of published literature, it was predicted that a 30% reduction in the efficacy of the prophylactic antibiotics routinely administered before orthopedic surgery could result in 120,000 more infections and 6,300 infection-related deaths every year in the USA alone³. 

Antibiotics are thus essential for the success of modern medicine, which involves more and more extensive interventions. Without antibiotics, even simple wounds and infections could become life-threatening and organ transplantations, cancer chemotherapy, and common surgeries, such as caesarean section, would be hazardous.

The threat of antibiotic resistance

Unfortunately, such a worrying scenario is not just a distant worry. Mounting evidence indicates that our heavy dependence on, and widespread misuse of antibiotics is reducing their efficacy. This is largely a result of the development of antibiotic resistance, which occurs when bacteria evolve to protect themselves from the effects of an antibiotic. New resistance mechanisms are emerging all the time, threatening our ability to treat common infectious diseases, such as septicemia, pneumonia, tuberculosis, and gonorrhea⁴.

When antibiotic-resistant bacteria infect humans and animals, the infections they cause are harder to treat than those caused by non-resistant bacteria, leading to higher medical costs, prolonged hospital stays, and increased mortality.

Dangerously high levels of antibiotic resistance have been reported across all parts of the world. In their evaluation of antimicrobial resistance, the World Health Organization found that more than 50% of infections with E. coli, K. pneumonia, and S. aureus were resistant to commonly used antibacterial drugs and concluded that death as a result of a minor injury is a very real possibility for the 21st Century⁵.

A recent study that investigated the efficacy of antibiotic prophylaxis found that nearly half of post-surgery infections, and over a quarter of infections after chemotherapy are caused by bacteria that are already resistant to standard prophylactic antibiotics used in the USA³. 

Furthermore, there is increasing concern that antibiotic resistance will reverse the tremendous progress made towards eradicating tuberculosis (TB). One in five cases of the disease are now resistant to at least one major anti-TB drug⁶. Mortality rates amongst patients with drug-resistant TB can be as high as 60%. 

Antibiotic resistance is thus putting the achievements of modern medicine at risk and increasing health care costs. Around two million people are infected by antibiotic-resistant bacteria each year, and it has been estimated that, unless we take action now, by 2050 ten million people will die annually from bacterial infections⁷.

Combating antibiotic resistance

Antibiotic resistance is accelerated by the misuse and overuse of antibiotics, as well as poor infection prevention and control. Steps need to be taken, by both healthcare professionals and the general population, as a matter of urgency to limit the development of further antibiotic resistance⁸. 

Healthcare professionals must reserve the use of antibiotics for only situations that genuinely necessitate them, and patients must ensure to use antibiotics as prescribed and finish the entire course of treatment.

In addition, behavioral changes to minimize the spread of infection and the need for antibiotics must be adopted. These include vaccination, and good handwashing and food handling practices. Without such changes on a global scale, antibiotic resistance will threaten, if not reverse, medical progress. 

In addition to limiting the development of antibiotic resistance, there is ongoing research to identify novel antibacterial strategies to limit our dependence on available antibiotics and reduce our vulnerability to the effects of increasing antibiotic resistance.

Antibacterial research

With the growing resistance of bacteria to even the strongest of available treatments, there has been increasing interest in the development of synthetic antibiotics. Numerous research projects are striving to develop novel antimicrobial treatments.

Synthetic versions of biological compounds with antibacterial action, such as antimicrobial peptides, and pyridines, that can be easily mass-produced are being investigated^9,10. In addition, novel strategies using a range of other compounds that have been shown to have antibacterial activity, including silver and zinc nanoparticles, are being explored^11,12. 

Supporting the development of new synthetic antibiotics are the tools used to research new antibiotic candidates and test them in varying conditions for efficacy and validity. A key contributor is microplate readers, which are valuable for both research into the development and prevalence of antibiotic resistance and the evaluation of potential new antibacterial agents. 

Microplate readers - an indispensable tool for antibacterial research

Microplate readers allow conventional light-based assays to be conducted in 96-well (or higher) format. This way, operational time is minimized and costs are reduced. The most abundant task for microplate readers in studying antibiotics is the monitoring of growth by measuring optical density at 600 nm. Alternatively, crystal violet staining can be employed to evaluate bacterial growth, for example to study the antibacterial properties of bacteriophages. Instead of drawing samples each 30 min and measuring each condition individually, the microplate experiment automatically acquires data of 96 samples at each chosen interval. Once started, there is no need for manual intervention. Though being the most popular application, multi-mode microplate readers by BMG LABTECH read a huge variety of assays, based on fluorescence, fluorescence polarization, luminescence, time-resolved fluorescence and FRET, AlphaScreen^® and absorbance. This high versatility provides the solution to address each question arising in antibiotic resistance research.

For example, a recent study by Salem et al.^11-12 featured a microplate reader from BMG LABTECH; the study investigated the effects of silver and zinc oxide nanoparticles in combatting E. coli and cholera. This study used the SPECTROstar Nano microplate reader to assess the quantity of silver and zinc oxide nanoparticles as they were produced. Cell growth was then tracked during exposure to varying levels of each nanoparticle. Absorbance spectra were used to characterize the nanoparticles and subsequently, the SPECTROstar Nano measured the antibacterial activity of nanoparticles in a biofilm assay. The study demonstrated that silver and zinc oxide nanoparticles can be used to combat bacterial biofilm formation and is an attractive method to help treat drinking water before it is consumed^11-12.

Another study employed the multiplexing capabilities of the CLARIOstar multi-mode reader to study translation influenced by a regulatory RNA and normalized it to bacterial growth. Gene expression was measured with a fluorescent beta-galactosidase assay, growth by absorbance at 600 nm¹³.

BMG LABTECH is proud to provide devices specifically meeting the requirements of antibiotic resistance research and thus helping to combat the emerging threat.

References

1. Perencevich EN, et al. Health and economic impact of surgical site infections diagnosed after hospital discharge. Emerg Infect Dis. 2003;9:196–203.
2. Sherry L, et al. Biofilms formed by Candida albicans bloodstream isolates display phenotypic and transcriptional heterogeneity that are associated with resistance and pathogenicity. BMC Microbiology2014;14:182.
3. Teillant A, et al. Potential burden of antibiotic resistance on surgery and cancer chemotherapy antibiotic prophylaxis in the USA: a literature review and modeling study. Lancet Infect Dis. 2015; 15(12):1429-37.
4. Tadros M, et al. Epidemiology and outcome of pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) in Canadian hospitals. PLoS One 2013;8:e75171.
5. World Health Organisation. Antimicrobial Resistance Global Report on Surveillance 2014.
6. Dheda K, et al. The epidemiology, pathogenesis, transmission, diagnosis, and management of multidrug-resistant, extensively drug-resistant, and incurable tuberculosis. The Lancet Respiratory Medicine Commission 2017;5(4):291 360.
7. de Kraker MEA, et al. Will 10 Million People Die a Year due to Antimicrobial Resistance by 2050? PLoS Med 2016;13(11):e1002184.
8. WHO Antibiotic Resistance Fact Sheet 2018. Available at http://www.who.int/news-room/fact-sheets/detail/antibiotic-resistance 
9. Azmi F, et al. Towards the Development of Synthetic Antibiotics: Designs Inspired by Natural Antimicrobial Peptides. Current Medicinal Chemistry 2016;23(41): 4610 4624.
10. Saloman L. New Synthetic Antibiotics May Combat MRSA and Other Superbugs. Contagion Live March 29, 2018. 
11. Salem W, et al. Antibacterial activity of silver and zinc nanoparticles against Vibrio cholerae and enterotoxic Escherichia coli. Int. J Med Microbiol. 2015;305(1):85 95
12. Salem W, Schild S. Detection of plant-synthesized nanoparticles and their antibacterial capacity. BMG LABTECH Application note 303.
13. Rochat T, et al. The conserved regulatory RNA RsaE down-regulates the arginine degradation pathway in Staphylococcus aureus. Nucleic Acids Res. 2018 Sep 28;46(17):8803-8816. doi: 10.1093/nar/gky584.