In this section, we analyze two groups of bacteria with completely different clinical significance, united by a common morphology: regular non-spore-forming gram-positive rods.
The section consists of two topics: Lactobacilli and Listeria. Lactobacilli are the foundation of our normal microflora and the primary protectors of mucous membranes (especially the vagina and intestines). Listeria, on the other hand, are insidious facultative intracellular parasites. Listeria monocytogenes causes severe foodborne toxicoinfections, meningitis, and sepsis, posing a colossal threat to pregnant women and newborns.
During colloquia and exams, professors will certainly ask about the mechanisms of intracellular survival of Listeria (the action of listeriolysin O and actin "tails"), as well as psychrophilic properties—the ability to multiply in a refrigerator. Regarding lactobacilli, it is important to know the mechanisms of antagonism toward pathogens (production of lactic acid and hydrogen peroxide) and the principles of probiotic development.