Department of Medical and Clinical Microbiology, Pavol Jozef Šafárik University in Košice, Faculty of Medicine

Complement is a system of more than 30 serum and membrane proteins. It represents part of the non-specific humoral immune response. The immune reaction is triggered after the cascade activation of complement components. The lecture explains basic terms, complement activation pathways, regulatory components of complement, basic functions, deficiencies of complement and possibilities of laboratory diagnostics of complement.

In diagnostics of infectious diseases direct and indirect diagnostic methods are used. Direct diagnostics allows to visualize microorganisms as agents of infection, indirect diagnostics allows to detect reactions of the macroorganism to the presence of the microorganism. Indirect diagnostics is focused on cellular immunity (skin tests), in which specific antibodies are demonstrated by serological reactions. The lecture is devoted to the explanation of basic terms (antigen, antibody, serological reaction, its course, evaluation) and the classification of serological reactions, which are used in clinical microbiology in the diagnosis of infectious disease agents. An illustrative image or procedure, reaction principle and specific examples of use are available for individual reactions.

Genetic information is stored in all cells in the form of a DNA, nucleic acid molecule. A segment of DNA that codes for a molecule with a specific function is a gene. It represents the basic unit of genetic information. In bacteria, DNA is most often found in the form of one chromosome and several smaller plasmids.

RNA are noncellular organisms with ribonucleic acid (RNA) in their genome. In most viruses, RNA is single-stranded (ssRNA). An exception is made by reoviruses, whose RNA is double-stranded (dsRNA).In addition, RNA is either segmented (the genome consists of several RNA segments) or unsegmented (one long strand of RNA). RNA viruses that have only a protein capsid on their surface are non-enveloped. RNA viruses, which in addition to the capsid have an additional envelope made of a bilayer of lipids and proteins and specific glycoproteins, are enveloped. The content of the lecture is the classification of RNA viruses and, for selected groups of RNA viruses, structure, replication in the host cell, pathogenicity, diseases, laboratory diagnostics, therapy and prevention are described.

Enterobacteria are gramnegative, facultative anaerobic bacteria that are rod-shaped. They occur in the natural environment, many are part of the human intestinal microflora (intestinal microbiome). According to the current classification, they belong to the order Enterobacterales, which includes 7 families, 66 genera and many species. Bacteria of the genera Escherichia, Enterobacter, Salmonella, Shigella, Klebsiella, Morganella, Proteus, Providencia, Serratia, Pantoea, Yersinia, Cronobacer, Citrobacter, Plesiomonas, Hafnia, are important in human medicine. The content of the lecture is the classification and basic properties of enterobacteria, pathogenicity, clinical syndromes, laboratory diagnostics, therapy and prevention are described for the most important enterobacteria.

The family of Mycobacteriaceae contains the single genus Mycobacterium with over 150 species. They are broadly distributed in various natural environments, and with several notable exceptions, they do not appear in parasitic or disease associations. This genus also includes Mycobacerium tuberculosis, currently responsible for serious bacterial infections of humans in many parts of the world, with millions of deaths annually. Other Mycobacterium species can cause a variety of infections as well; for example, worldwide, there are over quarter million new cases of leprosy, a debilitating disease caused by Mycobacterium leprae. A number of mycobacterial saprophytes have been shown to cause opportunistic infections in immunocompromised individuals, and many are pathogens of animals.