Superbacteria
Superbacteria are bacteria that have developed resistance to multiple antibiotic drugs, making infections caused by them challenging to treat. These organisms have become a significant global health threat, with antibiotic-resistant strains identified on every continent, including Antarctica. The rise of superbacteria is largely attributed to the widespread use of antibiotics in both healthcare and agriculture, leading to environments where bacteria can easily develop and share resistance traits. Infections caused by superbacteria, such as Methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant tuberculosis (MDR TB), can result in severe health complications, longer hospital stays, and increased mortality rates.
The mechanisms behind antibiotic resistance include vertical transmission, where resistant traits are passed through generations, and horizontal transmission, where resistance genes are shared between different bacterial species via plasmids. This ability allows bacteria to rapidly acquire multiple resistances, complicating treatment efforts. The COVID-19 pandemic further exacerbated the issue, as the unnecessary use of antibiotics during the crisis led to an increase in hospital-acquired infections. Addressing the challenge of superbacteria requires global strategies to curb antibiotic overuse and to foster the development of new treatment options.
Superbacteria
- ALSO KNOWN AS: Multidrug-resistant organisms, multidrug-resistant strains
Definition
Superbacteria are organisms that have developed resistance to many antibiotic drugs. Infections caused by these bacteria can be extremely difficult to treat, as some have become resistant to all antibiotics that were once effective against them. Because resistance can spread from one bacterium to another, resistant strains of many types of bacteria have emerged.
Superbacteria have become a serious health threat worldwide; antibiotic-resistant strains are present on every continent, including Antarctica. The incidence of illness caused by drug-resistant bacteria is increasing dramatically around the world. Resistant strains of disease-causing bacteria, originally found primarily in hospitals, have now moved beyond healthcare facilities and into communities.
Emergence and Spread of Superbacteria
When bacteria are exposed to an antibiotic, most of them will die. However, a few bacteria may acquire changes in their DNA (deoxyribonucleic acid) that allow them to survive in the presence of the drug. These bacteria will multiply, creating a drug-resistant group. This vertical transmission (that is, the method of passing resistance genes) requires time for resistance-causing mutations to arise and stays within the same type of bacteria.
The rapid spread of multiple resistance genes among species of bacteria occurs through a second method of gene transfer: horizontal transmission. Bacteria often carry their antibiotic resistance genes on bits of DNA called plasmids, which are commonly passed between bacteria. One plasmid can contain genes for resistance to numerous different antibiotics. Bacteria that receive such a plasmid will become resistant to multiple antibiotics in one rapid event. They can then spread this resistance even further when they multiply.
The widespread use of antibiotics in medicine and agriculture has led to the emergence and spread of superbacteria. Frequent exposure of bacteria to antibiotics increases the likelihood that they will develop resistance. Hospitals provide ideal conditions for bacteria to acquire resistance, because antibiotics are often used liberally and because many species of disease-causing bacteria are present.
Drug-resistant bacteria also arise on farms that produce meat and poultry, where antibiotics are routinely given to healthy animals to prevent disease and to promote growth. Incomplete treatment of pathogens with antibiotics can also promote resistance. When a person stops taking prescribed antibiotics before all bacteria are eliminated, the remaining bacteria may become resistant.
Although progress had been made in the fight against superbacteria, the COVID-19 pandemic represented a setback for healthcare workers. During the initial outbreak, many patients were administered antibiotics unnecessarily as scientists and doctors scrambled to treat sick patients. Hospital-acquired infections and related deaths increased drastically following the COVID-19 pandemic, after steadily falling for the previous decade.
Associated Diseases and Pathogens
Staph infections. Methicillin-resistant Staphylococcus aureus (MRSA) causes skin and soft tissue infections, which can be invasive and life-threatening. MRSA is usually resistant to aminoglycosides, macrolides, tetracycline, chloramphenicol, lincosamides, and methicillin. MRSA infection is a major public health problem. According to the Centers for Disease Control and Prevention (CDC), MRSA infection in 2017 caused life-threatening illness in 120,000 people and 20,000 deaths in the United States alone. The CDC estimates that MRSA is responsible for around 9,000 deaths and more than 70,000 severe infections in the United States each year.
Tuberculosis. Nearly one-third of the world’s population is infected with Mycobacterium tuberculosis, the bacterium that causes the lung disease tuberculosis (TB). About 10 percent of those infected will develop TB. The rise of antibiotic resistance now threatens the only treatment for TB, which is antibiotic therapy. Strains of M. tuberculosis that are resistant to a minimum of one antibiotic have been documented in every country surveyed by the World Health Organization. Multidrug-resistant TB (MDR TB) is caused by strains of M. tuberculosis that are resistant to both isoniazid and rifampicin, the two most effective anti-TB drugs.
Opportunistic infections. Persons with compromised immune systems are vulnerable to infection by organisms that are normally harmless in healthy people. Acquired in hospitals, opportunistic infections can be life-threatening without appropriate antibiotic treatment. Drug-resistant strains of the bacteria responsible for these infections pose a growing threat to hospitalized persons. The CDC estimates that annually, one million persons in the United States get some sort of hospital-acquired infection (HAI); 70 percent of the bacteria that cause these infections are resistant to a minimum of one antibiotic typically used to treat them.
Strains of Klebsiella pneumoniae have developed resistance to carbapenems, one of the few classes of antibiotics effective against these gram-negative bacteria. Enterobacter variants are also carbapenem-resistant, and they are resistant to all penicillin derivatives and cephalosporins. Enterococcus faecium has developed strains that are resistant to both ampicillin and vancomycin. Pan-resistant strains of Pseudomonas aeruginosa and Acinetobacter baumannii are no longer treatable with any known antibiotics.
Impact
Superbacteria present a serious global threat to human health. The worldwide spread of antibiotic resistance jeopardizes the usefulness of antibiotics in the treatment of bacterial diseases. Healthcare providers increasingly face the challenge of treating infections for which few or no effective antibiotics exist. People with resistant infections face longer hospital stays, more severe illness, and an increased chance of death from certain diseases. The resulting costs are high, both in terms of health care dollars and human lives. Solutions will require global efforts to reduce the overuse and misuse of antibiotics, to prevent the spread of resistant organisms, and to develop new antibiotic agents.
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