Antibiotics are up there with vaccines and clean water as among the most important medical discoveries of all time. Prior to the serendipitous discovery of penicillin by Alexander Fleming in the 1920s, doctors had very few tools to treat bacterial infection. Many women died after giving birth due to infections from poor hygienic practices during delivery. A simple toothache could be a dental abscess that can turn fatal if the bacteria cross the bloodstream. A skin infection on the foot of a diabetic person could progress leading to a gangrenous limb that needs to be amputated. While these infections do still happen in this day and age, the complications and high mortality are a thing of the past, thanks to antibiotics.
Antibiotics, strictly speaking, are any kind of medicine that can affect microbes by interfering with their life processes. Microbes include bacteria, viruses (kind of alive), fungi, protozoans, and even algae. The current usage of the term antibiotic refers to a medicine that specifically kills or inhibits bacteria. Agents that work against viruses and fungi are called antivirals and antifungals, respectively. This is why doctors say antibiotics don’t work against the common cold, which is caused by a virus.
The first antibiotics were natural products, such as penicillin derived from the mold Penicillum. These compounds were cultivated, purified, and concentrated into a form potent enough to kill bacteria in human beings without harming the host. Aside from the original penicillin molecule, other antibiotics have been developed using the penicillin blueprint through chemical alteration or discovery of variants from other molds. The effect of antibiotics on otherwise deadly illnesses was nothing short of miraculous. In the 1960s, many people thought that the era of infections from bacteria was coming to an end because of how well antibiotics worked.
Unfortunately, the bacteria did not go down without a fight. Within a few years following the widespread use of penicillin, penicillin resistant strains of bacteria started to appear. To combat these, scientists formulated better antibiotics. The bacteria then became resistant to those. The antibiotic arms race was on.
Despite being made up of just a single cell, bacteria are remarkably adaptable organisms. Bacteria have been on earth at least two billion years longer than other organisms and in that period have developed amazing diversity. There are bacteria that can tolerate very hot or very cold temperatures. There are bacteria that can live in the deep ocean or in the scorching desert. It comes as no surprise that bacteria have developed resistance to almost all of the antibiotics that man has made, and these antibiotic-resistant strains are becoming the dominant forms not just inside hospitals but also in the community.
Known as “superbugs,” these bacteria are now widespread and no longer respond to the most common antibiotics. Some are so resistant that the only antibiotics that remain effective need to be given intravenously and in combination with other agents. Among these superbugs that are of greatest concern to the World Health Organization (WHO) are the so-called ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa and Enterobacter species) organisms. The strains of these bacteria that are specifically resistant to very strong antibiotics include MRSA (methicillin-resistant Staphylococcus aureus), VRE (vancomycin resistant Enterococcus), CRE Klebsiella pneumoniae and CRE Enterobacter (Carbapenem Resistant Enterobacterales Klebsiella pneumoniae and Enterobacter), CR Pseudomonas (Carbapenem Resistant Pseudomonas aeruginosa), and CR Acinetobacter (Carbapenem Resistant Acinetobacter baumanii).
In the Philippines, the resistance to one of the last-line class of antibiotics known as carbapenems (meropenem, imipenem, ertapenem) has increased drastically in the last decade. Klebsiella pneumoniae, a common cause of urinary tract infections (UTIs) and pneumonia, has seen meropenem resistance more than triple from below five percent in 2012 to 16 percent in 2022. Prior to the rise of meropenem resistance was an even bigger increase in resistance to a class of drugs known as cephalosporins, which have been the mainstays of treatment for these organisms. Resistance to ceftriaxone, a third generation cephalosporin, currently stands at 44.9 percent while resistance to ciprofloxacin, which is commonly used for UTIs, is 48.6 percent. Doctors are forced to use stronger and stronger (and much more expensive) antibiotics as resistance increases, which in turn drives resistance to these stronger antibiotics.
One of the most common reasons patients are referred to infectious diseases physicians like me is antibiotic resistance. Imagine a patient with a UTI, which then grows a resistant Klebsiella or E. coli that can only be treated with intravenous antibiotics. This usually requires admission to the hospital and much more expensive antibiotics. With a fully susceptible bacteria, the cost would be a mere fraction of this since the treatment would be a cheap generic oral antibiotic, which can be given as an outpatient. Worse, having to use antibiotics higher and higher in class drives resistance to these agents to the point where, in some cases, we have nothing left. Another common referral to us is a hospitalized patient who is growing bacteria that is resistant to all agents on the antibiogram. While infectious disease physicians do still have ways to address these using combination treatment and novel agents, it doesn’t work all the time. Patients infected with antibiotic resistant strains of bacteria have a two-fold risk of dying compared to those with antibiotic susceptible strains.
Antibiotic resistance is a global crisis, which disproportionately affects poorer countries like ours. It is in everyone’s best interest that good antibiotic stewardship is practiced as part of good medicine. While there are many challenges in ensuring rationale antibiotic use, the first step to addressing this problem is to have it recognized as a priority by everyone. Public education is important in ensuring that antibiotics continue to protect us from bacterial infections. Best practices for minimizing the emergence of antibiotic resistance need to be promoted and followed by everyone. These include only taking antibiotics when prescribed by a doctor, finishing your antibiotic course, following hospital protocols for proper use of antibiotics, and working with the agricultural sector to avoid routine use of antibiotics in animal feed. In this existential fight against microbes, we need all the human help we can get.