By Matt Boyce, 2nd-year MSc-GH student
Emerging and re-emerging diseases have monopolized public health media coverage for much of recent history. Infectious disease outbreaks such as SARS, bird flu, swine flu, Ebola and Zika have captured the attention of audiences around the world.
Still, leading health experts say an even more serious threat to public health may be on the horizon—antibiotic-resistant bacteria. The World Health Organization (WHO) recently issued an unprecedented warning, listing a dozen antibiotic-resistant bacteria that pose considerable threats to human health.
How did we get here?
These threats have been precipitated by two factors: the abuse of antibiotics and a lack of viable drug alternatives.
Antibiotic-resistance occurs when bacteria gradually evolve to survive exposure to antibiotics. Though this resistance occurs naturally over time, the misuse and overuse of antibiotics in both humans and livestock have accelerated the process.
Throughout much of the world, antibiotics are used without proper oversight, resulting in their abuse. Examples include when humans take antibiotics to fight infections caused by viruses (like the flu), when humans start an antibiotic treatment but do not finish taking all the antibiotics, or when antibiotics are used as growth promoters in livestock. The cumulative results of these actions are ineffective medicines and persistent, untreatable infections.
The Burden of Antibiotic Resistance
The United States Centers for Disease Control and Prevention estimate the infections caused by antibiotic-resistant bacteria result in some two million cases of illness and 23,000 deaths in the U.S. annually. The European Centre for Disease Prevention and Control produces similar numbers, estimating that antibiotic-resistant bacteria kill approximately 25,000 Europeans every year.
The Role of Pharmaceutical Companies
Another alarming feature of the present situation is that pharmaceutical companies have been unable to develop new, viable antibiotic alternatives. Pharmaceutical companies are often reluctant to invest in antibiotic research and development because antibiotics do not offer favorable returns- on- investment. People use antibiotics only for limited periods of time, making them less profitable than other drugs, such as those used to treat chronic diseases.
WHO says this list is an attempt make the development of new and effective antibiotics an international health priority for pharmaceutical companies. The list, drafted by a group of international health experts, assessed bacteria for inclusion based on several key characteristics:
- Mortality rates
- Global prevalence of antibiotic-resistance
- Likelihood of transmission and prevention
- Burden posed to health systems and communities
The resulting has three severity categories: critical, high and medium priorities.
WHO’s Bacteria Priorities
The three bacteria listed as critical priorities include Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacteriaceae. These bacteria are most commonly contracted from contaminated food, water or hospital equipment. The resulting infections can cause severe, life-threatening illnesses—including pneumonia and gastrointestinal illness—for which there are no effective treatments.
WHO listed six high-priority bacteria that include methicillin-resistant Staphylococcus aureus (MRSA), which can result in severe skin disease, Enterococcus faecium, and Neisseria gonorrhoeae, the bacteria responsible for the sexually transmitted infection gonorrhea. Other high-priority bacteria include Helicobacter pylori, Campylobacter and Salmonellae, which can result in serious gastrointestinal illness and diarrheal disease.
The final category—medium priority—is composed of bacteria that may be prevented using immunization or are currently curable, but display significant levels of resistance. These bacteria include drug-resistant versions of Streptococcus pneumoniae, Haemophilus influenzae and shigella. These bacteria can cause many types of serious childhood illnesses, including pneumonia, ear infections, sinus infections, meningitis and diarrheal disease.
One notable omission from the list was Tuberculosis, even though the illness associated with drug-resistant strains—known as MDR-TB and XDR-TB—pose major public health threats. WHO justified this omission by citing that programs targeting these bacteria and related infection already exist. Other notable omissions include malaria and HIV. Though there are significant concerns about resistance for these diseases, they are not caused by bacteria, and therefore untreatable using antibiotics.
Development of New Treatments Is Critical
While public health officials and researchers argue that conserving current antibiotic treatment is of equal importance as developing new antibiotics, there is a clear need to encourage the development of new treatments.
Several countries have already begun these efforts. This past year the United States government launched the BARDA Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator to fund antibiotic research through public-private partnerships. The United Kingdom and China have also partnered to form the Global Antimicrobial Resistance Research Innovation Fund, an effort that aims to create international partnerships to address and reduce the spread of antibiotic resistance.
The public bears the burden of antibiotic resistance, but private companies are the ones who must spearhead the development of new treatments. Developing the required antibiotics to address this impending public health threat will require consistent international support, innovative partnerships between public, private and governmental actors, and a spot on the global health policy agenda.
Only time will tell if these efforts to develop new antibiotics and mitigate the risk of antibiotic resistance will prove successful. Otherwise, we may face a future reality of a post-antibiotic era that will have serious implications not only for public health, but also for the global economy.