A superbug is a bacterium which has developed resistance to multiple antibiotics. Also known as multiresistant bacteria, superbugs are a major concern in the public health community around the world, as they present a serious threat to patients, especially hospitalized patients and patients with compromised immune systems. These bacteria are also of interest to pharmaceutical companies, as they are a driving force behind the need to develop new classes of antibiotics.
Superbugs develop because bacteria are highly adaptable. When antibiotics are introduced to the body in an attempt to eradicate bacteria, these drugs are often highly effective at killing off bacteria, but a few bacteria usually continue to grow. In individuals who are relatively healthy, the immune system may kill off these bacteria, but in others, the bacteria will multiply and spread, passing the gene for resistance to a specific antibiotic along.
Resistance to one antibiotic is not very uncommon in the bacterial community, thanks to the exchange of genetic material between bacteria. When a bacterium becomes multiresistant, however, it can become a serious problem, as it may pass the multiresistant genes on and create a superbug. Treating superbugs is challenging, as it is necessary to either culture the bacteria to find out which antibiotic can be used against them, or to use multiple courses of antibiotics in an attempt to wipe them out, and to hope that the use of multiple antibiotics doesn't actually create more antibiotic resistance.
Some infamous superbugs include bacteria in the Streptococcus and Enterococcus genera, along with Staphylococcus aureus and Clostridium difficile. These superbugs are commonly observed in hospital environments, because hospitals are ideal breeding grounds for multiresistant bacteria, between all of the antibiotics used in the hospital environment and all of the sick patients who are vulnerable to bacterial colonization. Concerns about drug resistance have led many hospitals to enact strict sterilization and hygiene policies to reduce the risk of passing drug resistant organisms between patients.
The biggest concern with a superbug is the development of a bacterium which would be capable of resisting all antibiotics on the market, making it effectively impossible to eradicate. As it is, treating patients with superbug infections is complicated by the cost of antibiotics, the health issues individual to each patient, the accessibility of drugs, and the difficulty of getting patients to adhere to antibiotic regimens. The emergence of a superbug which resisted all drugs could be a public health disaster.