Flagella: it is a slender wavy filament on bacteria, and it is the motor organ of bacteria.
According to the number and position of flagella, flagellates can be divided into four categories: ① Trichomonas; ② Trichophyton; ③ Trichophyton: One or both ends of the thallus have a cluster of flagella; ④ Peritrichomes: Bacteria are covered with flagella.
The function of flagella is:
① Identification value: Flagella is the motor organ of bacteria, and whether bacteria can move can be used for identification.
② Pathogenicity: The flagella movement can strengthen the collection and arrangement of bacteria invading the host by the Medical Education Network, because the movement often has a chemical tendency and can avoid harmful environment or move in the direction of high concentration environment.
③ Antigenicity: Flagella has special H antigen, which can be used for serological examination.
Fimbriae: Thin, shorter and harder filaments on the surface of bacteria than flagella. No fimbriae can be seen under ordinary optical microscope, so it must be observed by electron microscope. The fimbriae is composed of fimbriae protein, which is a structural protein subunit with antigenicity.
According to different functions, fimbriae can be divided into ordinary fimbriae and sexual fimbriae:
① Common fimbriae: It can bind to specific receptors on the surface of host cells, which is the first step of bacterial infection, and fimbriae is closely related to the pathogenicity of bacteria;
② Sexual fimbriae: longer and thicker than common fimbriae, hollow and tubular. Found in a small number of gram-negative bacteria, the number is small, and one bacteria is only 1? Four. It is encoded by F plasmid, also called F fimbriae. Bacteria with sexual pili are called F+ bacteria or male bacteria, and those without sexual pili are called F- bacteria or female bacteria. When F+ bacteria meet F- bacteria, the fimbriae of F+ bacteria combine with the corresponding fimbriae receptor of F- bacteria, and the plasmid or chromosomal DNA in F+ bacteria can enter F- bacteria through the hollow fimbriae. Mediate the transfer of bacterial genetic material between bacteria.
Spore: Under certain environmental conditions, some bacteria can form round or oval bodies inside bacteria, which is the dormant form of bacteria. All the bacteria are Gram-positive, so it is important to collect and sort out Bacillus (Bacillus anthracis, etc.). ) and Clostridium (Clostridium tetanus, etc. ) by Medical Education Network.
The size, shape and location of spores vary from strain to strain, which has important identification value.
Bacterial spores have strong resistance to physical and chemical factors such as heat, dryness, radiation and chemical disinfectants. General disinfection methods are not easy to kill spores, and the most reliable method to kill spores is high-pressure steam sterilization. When sterilizing, whether spores are killed or not should be used as an index to judge the sterilization effect.
Spores do not cause disease directly, but only when they germinate into propagules.