Antibiotics cannot kill viruses because viruses have different structures and replicate in a different way than bacteria.
Antibiotics work by targeting the growth machinery in bacteria (not viruses) to kill or inhibit those particular bacteria.
Viruses, especially those made of RNA, can mutate rapidly to give rise to new types. Hosts may have little protection against such new forms. Influenza virus, for example, changes often, so a new vaccine is needed each year. Major changes can cause pandemics.
Viruses insert their genetic material into a human cell’s DNA in order to reproduce. Antibiotics cannot kill viruses because bacteria and viruses have different mechanisms and machinery to survive and replicate. The antibiotic has no “target” to attack in a virus.
Coronaviruses contain a positive-sense, single-stranded RNA genome. The genome size for coronaviruses ranges from 26.4 to 31.7 kilobases.
- two major classes of antibiotics, the rifamycins and the quinolones and fluoroquinolones. Rifamycins inhibit the bacterial RNA polymerase, preventing transcription, and they are special because they can penetrate well into cells and tissues.
- Antibiotics do not directly affect SARS-CoV-2, the respiratory virus responsible for COVID-19, but viral respiratory infections often lead to bacterial pneumonia.
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new coronavirus that was only recently discovered in 2019. The virus causes the COVID-19 pandemic which currently requires the full focus.
Positive blood test result for the new rapidly spreading Corona/Covid19 virus. Photo: Shutterstock.
ReAct is however, carefully monitoring the field and is assessing the data that is emerging and intersect with antibiotic resistance. Here we try to provide an overview of what is known so far about how AMR and COVID-19 relate.
- Bacteria or viruses – what is the difference?
Although bacteria and viruses both are known to be disease-causing agents, they are fundamentally different. Bacteria are single-celled organisms that are found all around us – including in and on our bodies. There is a huge variety of bacterial species and they have important roles to play in all kinds of ecosystems. Antibiotics can be used to treat bacterial infections, but only a fraction of bacteria actually cause disease.
Viruses, on the other hand, are not made up of cells. They are composed of genetic material – DNA or RNA – that is covered by a coat of protein. Unlike bacteria, viruses lack ability to reproduce independently and therefore need to enter cells of other host organisms to be able to multiply. As such they are always parasitic, regardless of the host being a human, an animal, a plant or a bacterium. The virus causing COVID-19 spreads through respiratory droplets, primarily when an infected person coughs or sneezes.
- Viral infections, COVID-19 included, cannot be treated with antibiotics. However, some viral infections may damage our cells so badly that it becomes easier for certain bacteria to cause so-called secondary infections. A fairly common example is bacterial pneumonia in influenza patients, which can be treated with antibiotics.
- The World Health Organization (WHO) is very clear that antibiotics do not work against viruses, only bacteria, and yet health care providers are using antibiotics in some patients with COVID-19. This is because:
Patients with viral pneumonia can develop a secondary bacterial infection that may need to be treated with an antibiotic, although, this complication is reported to be uncommon early on in the course of COVID-19 pneumonia.
- If treatment is required for a secondary bacterial infection then a range of antibiotics can be used such as penicillins (ampicillin plus sulbactam [Unasyn], piperacillin plus tazobactam [Zosyn]), macrolides (azithromycin), cephalosporins (ceftriaxone [Rocephin]), aminoglycosides (tobramycin) and glycopeptides (vancomycin [Vancocin HCL]) for example. Often a combination of two different antibiotics is used.
- Azithromycin is also thought to have antiviral and anti-inflammatory activity and may work synergistically with other antiviral treatments. In in vitro laboratory studies azithromycin has demonstrated antiviral activity against Zika virus and against rhinoviruses, which cause the common cold.
- But in some parts of the United States, 30% to 40% of some common types of bacteria were already resistant to the class of drugs that includes azithromycin, and overuse could render those or other antibiotics even less effective.
There is no specific treatment for disease caused by a novel coronavirus. However, many of the symptoms can be treated and therefore treatment based on the patient’s clinical condition.