Bacteria, viruses and fungi can cause considerable harm to humans, and they are extremely tricky in doing so. Infectiologists are therefore particularly challenged. A look at an exciting branch of internal medicine at Vivantes.
Attack from the microworld #1
Infectiology is the study of diseases caused by microbes and parasites and is a branch of internal medicine. The discipline includes diagnosis, therapy, and prophylaxis, as well as the study of microbes, parasites, the immune system, and the development of new therapies and drugs. Microbes are tiny living organisms that surround us: in water, in the earth, in the air, and millions of times also in our bodies (microorganisms). The most common are bacteria, viruses and fungi. The group of protozoa (microorganisms) cause diseases such as toxoplasmosis or malaria. Most bacteria do not endanger humans. Many of them live on or in our bodies and help us stay healthy. Lactic acid bacteria in the intestines, for example, aid digestion. Others help the immune system by fighting pathogens. A rough estimate is that less than one percent of all bacteria are responsible for disease. However, some, such as tuberculosis, are caused exclusively by bacteria.
The discovery of penicillin was a milestone in the fight against infectious diseases. The Scottish bacteriologist Sir Alexander Fleming received the Nobel Prize for it in 1945. Almost 40 years later, another turning point: in 1981, doctors in the USA reported the first cases of a new disease in previously healthy, young, homosexual men. One year later, the first cases are reported in Germany – AIDS. Probably the most spectacular innovation in infectious diseases in the past 22 years was the development of a therapy against the HI virus: a fatal disease became a treatable one. Those affected now have an almost normal life expectancy and quality of life. There have also been successes with treatments for hepatitis C, vaccinations and antibiotics. However, increasing resistance and threats from epidemics or even pandemics, such as Coronavirus at present, continue to pose major challenges.
Attack from the microworld #2
Antibiotics (drugs) kill bacteria or prevent them from reproducing further. Other infections, such as colds, tonsillitis, or diarrhea, can also be caused by bacteria, but the causative agents are largely viruses. Antibiotics are ineffective against viruses. They penetrate healthy cells and make us sick. They multiply out of the host cell. Unlike bacteria, viruses have no cells of their own, so they are not living organisms in the true sense of the word. They consist of one or more molecules and are surrounded by a protein envelope. The viruses need the genetic information contained in this envelope in order to reproduce. Many types of viruses cause diseases. Some of them are harmless, others serious, for example the flu, liver inflammation (viral hepatitis) or AIDS and currently Corona. Viruses use clever tricks to hijack human cells. Not all of them cause symptoms; in many cases, the body successfully fights back. Drugs have a relatively hard time fighting viruses. Vaccinations "train" the defenses and thus make the body less susceptible. Fungi are widespread and adapted to different habitats. Like bacteria, some of them occur naturally on the skin or in the body, but they can also trigger diseases - these are called mycoses.
Up to date: Covid-19 infections
Infectiology at Vivantes Auguste-Viktoria Hospital is clinically oriented. Physicians and nursing staff provide inpatient and outpatient care for patients with infectious diseases, but also participate in clinical trials for the development of vaccines and drugs. Dr. Anja Masuhr is the senior physician in charge of infectious diseases at the AVH. She describes the current situation against the backdrop of the Corona pandemic: "Since the beginning of the spread, we have made one of the two infectious disease wards available exclusively for patients with confirmed Covid-19 infection. They have to be monitored very closely, receive oxygen and fluids and antipyretic drugs via the veins. If respiratory deterioration occurs, we also arrange for transfer to the intensive care unit."
Focus on HIV and AIDS
Outside of this exceptional situation, the focus of infectious diseases at Vivantes Auguste-Viktoria Hospital is on the treatment of patients with HIV and AIDS. Dr. Anja Masuhr:"We have decades of treatment experience in our hospital. All departments are familiar with this clinical picture." HIV disease is now easily treatable. Although there is still no vaccine to prevent infections, so-called "antiretroviral" drugs (directed against a retrovirus such as the HI virus) suppress the multiplication of the virus in the blood to such an extent that infection is almost impossible if the viral load is undetectable. As a result, those affected have an almost comparable life expectancy to people who are not infected.
The senior physician describes the extent to which infectiology is dependent on close cooperation with other disciplines with an example: "We still frequently encounter the 'late presenter'. These are patients who previously did not know that they were infected with HIV and who are assigned to full-blown AIDS. Interdisciplinary cooperation is very important here, because an HIV infection can affect all organ systems." The professional exchange and close cooperation with other specialties make it clear how broadly infectious diseases is positioned, and give the work in this area an additional appeal. Dr. Anja Masuhr gives further examples: "Depending on which organ is affected by the infection, we involve colleagues from other specialties. In the case of infections of the central nervous system, such as meningitis, we work closely with neurologists. In the case of infections of the urogenital tract, such as severe urinary tract infections or inflammation of the renal pelvis, it is important to consult with urologists in order to rule out the possibility of a tumor as the cause. Conversely, surgery, orthopedics or spine specialists consult us when patients develop infections in the area of the vertebral bodies or joint implants after surgery. We work hand in hand with cardiologists and gastroenterologists to find the causes of inflammations in the heart or gastrointestinal tract. Interdisciplinary collaboration with other specialties is essential for optimal treatment, because all physicians with their respective special knowledge are involved."
Germ testing in the laboratory
Patients with fever and an unclear infection are often referred to the infectious diseases department via the emergency department at Vivantes Auguste-Viktoria Hospital. "We then look for the focus of the infection, guided by the complaints in addition to the fever," reports the senior physician. Close contact with the microbiologists is important for drug treatment. In the laboratory, they detect the relevant germs from the blood and urine samples and create a "resistogram", an antibiotic resistance determination. This provides information about the antibiotics to which a particular bacterial pathogen is resistant or sensitive. "We often start our treatment with a so-called calculated antimicrobial therapy; it first inhibits the growth of microorganisms, for example bacteria. If needed, we then switch to a drug that most effectively fights the germ identified in the lab." Despite many successes and advances, the diagnosis and treatment of infections remain among the most important tasks in medicine. The spread of coronavirus is emphatic evidence of this. Scientists are feverishly researching a vaccine.
Attack from the microworld #3
These include, for example, foot and nail fungus infections, but also pneumonia or mucous membrane infections in the mouth or on sexual organs. If the immune system is weak, they can become life-threatening. Fungi also have helpful properties: We owe the discovery of penicillin, for example, to a mold from which this antibiotic can be obtained. Parasites include lice, ticks and worms. These parasites nest in humans. Ecto- or external parasites, such as mites, ticks, lice, fleas, bugs or mosquitoes, live on the surface of the body. They, too, can cause disease or transmit infections. Endoparasites such as worms or flukes, on the other hand, settle inside the host, often in the intestine, but also in other organs, such as the liver, skin or muscles. Parasites have one thing in common: they lay eggs and reproduce and spread in this way.