An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of such infections. They may either kill or inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the ones which cause the common cold or influenza; drugs which inhibit growth of viruses are termed antiviral drugs or antivirals rather than antibiotics. They are also not effective against fungi; drugs which inhibit growth of fungi are called antifungal drugs.
Antimicrobial resistance (AMR) occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials. All classes of microbes can evolve resistance where the drugs are no longer effective. Fungi evolve antifungal resistance, viruses evolve antiviral resistance, protozoa evolve antiprotozoal resistance, and bacteria evolve antibiotic resistance. Together all of these come under the umbrella of antimicrobial resistance. Microbes resistant to multiple antimicrobials are called multidrug resistant (MDR) and are sometimes referred to as superbugs. Although antimicrobial resistance is a naturally occurring process, it is often the result of improper usage of the drugs and management of the infections.
Plague is an infectious disease caused by the bacterium Yersinia pestis. Symptoms include fever, weakness and headache. Usually this begins one to seven days after exposure. There are three forms of plague, each affecting a different part of the body and causing associated symptoms. Pneumonic plague infects the lungs, causing shortness of breath, coughing and chest pain; bubonic plague affects the lymph nodes, making them swell; and septicemic plague infects the blood and can cause tissues to turn black and die.
Cholera is an infection of the small intestine by some strains of the bacterium Vibrio cholerae. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea lasting a few days. Vomiting and muscle cramps may also occur. Diarrhea can be so severe that it leads within hours to severe dehydration and electrolyte imbalance. This may result in sunken eyes, cold skin, decreased skin elasticity, and wrinkling of the hands and feet. Dehydration can cause the skin to turn bluish. Symptoms start two hours to five days after exposure.
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an illness resulting from an infection.
An epidemic is the rapid spread of disease to a large number of hosts in a given population within a short period of time. For example, in meningococcal infections, an attack rate in excess of 15 cases per 100,000 people for two consecutive weeks is considered an epidemic.
Shigellosis is an infection of the intestines caused by Shigella bacteria. Symptoms generally start one to two days after exposure and include diarrhea, fever, abdominal pain, and feeling the need to pass stools even when the bowels are empty. The diarrhea may be bloody. Symptoms typically last five to seven days and it may take several months before bowel habits return entirely to normal. Complications can include reactive arthritis, sepsis, seizures, and hemolytic uremic syndrome.
Melioidosis is an infectious disease caused by a gram-negative bacterium called Burkholderia pseudomallei. Most people exposed to B. pseudomallei experience no symptoms; however, those who do experience symptoms have signs and symptoms that range from mild, such as fever and skin changes, to severe with pneumonia, abscesses, and septic shock that could cause death. Approximately 10% of people with melioidosis develop symptoms that last longer than two months, termed "chronic melioidosis".
Klebsiella pneumoniae is a Gram-negative, non-motile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium. It appears as a mucoid lactose fermenter on MacConkey agar.
Leptospirosis is a blood infection caused by the bacteria Leptospira that can infect humans, dogs, rodents and many other wild and domesticated animals. Signs and symptoms can range from none to mild to severe. Weil's disease, the acute, severe form of leptospirosis, causes the infected individual to become jaundiced, develop kidney failure, and bleed. Bleeding from the lungs associated with leptospirosis is known as severe pulmonary haemorrhage syndrome.
Gastroenteritis, also known as infectious diarrhea or simply as gastro, is an inflammation of the gastrointestinal tract including the stomach and intestine. Symptoms may include diarrhea, vomiting, and abdominal pain. Fever, lack of energy, and dehydration may also occur. This typically lasts less than two weeks. Although it is not related to influenza, in the U.S. it is sometimes called the "stomach flu".
Disease Informatics (also infectious disease informatics) studies the knowledge production, sharing, modeling, and management of infectious diseases. It became a more studied field as a by-product of the rapid increases in the amount of biomedical and clinical data widely available, and to meet the demands for useful data analyses of such data.
The Infectious Diseases Society of America (IDSA) is a medical association representing physicians, scientists, and other healthcare professionals who specialize in infectious diseases. It was founded in 1963 and is based in Arlington, Virginia. As of 2018, IDSA had more than 11,000 members from across the United States and nearly 100 other countries on six different continents. IDSA's purpose is to improve the health of individuals, communities, and society by promoting excellence in patient care, education, research, public health, and prevention relating to infectious diseases. It is a 501(c)(6) organization.
Medical microbiology, the large subset of microbiology that is applied to medicine, is a branch of medical science concerned with the prevention, diagnosis and treatment of infectious diseases. In addition, this field of science studies various clinical applications of microbes for the improvement of health. There are four kinds of microorganisms that cause infectious disease: bacteria, fungi, parasites and viruses, and one type of infectious protein called prion.
The following outline is provided as an overview of and topical guide to medicine:
The genomic epidemiological database for global identification of microorganisms or global microbial identifier is a platform for storing whole genome sequencing data of microorganisms, for the identification of relevant genes and for the comparison of genomes to detect and track-and-trace infectious disease outbreaks and emerging pathogens. The database holds two types of information: 1) genomic information of microorganisms, linked to, 2) metadata of those microorganism such as epidemiological details. The database includes all genera of microorganisms: bacteria, viruses, parasites and fungi.
Infectious diseases or ID, also known as infectiology, is a medical specialty dealing with the diagnosis and treatment of infections. An infectious diseases specialist's practice consists of managing nosocomial (healthcare-acquired) infections or community-acquired infections. An ID specialist investigates and determines the cause of a disease. Once the pathogen is known, an ID specialist can then run various tests to determine the best antimicrobial drug to kill the pathogen and treat the disease. While infectious diseases have always been around, the infectious disease specialty did not exist until the late 1900s after scientists and physicians in the 19th century paved the way with research on the sources of infectious disease and the development of vaccines.
Antimicrobial stewardship is the systematic effort to educate and persuade prescribers of antimicrobials to follow evidence-based prescribing, in order to stem antimicrobial overuse, and thus antimicrobial resistance. AMS has been an organized effort of specialists in infectious diseases, both in Internal Medicine and Pediatrics with their respective peer-organizations, hospital pharmacists, the public health community and their professional organizations since the late 1990s. It has first been implemented in hospitals. In the U.S., within the context of physicians' prescribing freedom, AMS had largely been voluntary self-regulation in the form of policies and appeals to adhere to a prescribing self-discipline until 2017, when the Joint Commission prescribed that hospitals should have an Antimicrobial Stewardship team, which was expanded to the outpatient setting in 2020.
Robert Steffen is an Emeritus Professor at the Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Switzerland and an adjunct professor at the University of Texas School of Public in Houston. He is an editor of the Journal of Travel Medicine.
Ramanan Laxminarayan Ph.D., M.P.H., FIDSA is an economist and an epidemiologist. He is founder and director of the One Health Trust – formerly known as the Center for Disease Dynamics, Economics & Policy (CDDEP) – in Washington, D.C., and director of the World Health Organization Collaborating Center for Antimicrobial Resistance. Laxminarayan is a senior research scholar at Princeton University, an affiliate professor at the University of Washington, a senior associate at the Johns Hopkins Bloomberg School of Public Health, and a visiting professor at the University of Strathclyde. In 2023, he was appointed an honorary visiting professor at the National University of Singapore Saw Swee Hock School of Public Health. His research on epidemiological models of infectious diseases and economic analysis of drug resistance, and research on public health gets attention from leaders and policymakers worldwide. He served on the President Obama's Council of Advisors on Science and Technology’s antimicrobial resistance working group. He served as a voting member of the U.S. Presidential Advisory Council on Combating Antimicrobial Resistance from 2015 to 2023. He has served as chairperson of the Global Antibiotic Research and Development Partnership (GARDP), a not-for-profit organization dedicated to developing new antimicrobials, since its founding. GARDP was created by the World Health Organization and the Drugs for Neglected Diseases Initiative (DNDi).
