Lec 1

Microbiology

The study of organisms and agents too small to be seen by the naked eye.

Microorganisms

Organisms that are too small to be seen with the unaided eye, including bacteria, fungi, protozoa, helminths, and viruses.

Medical microbiology

The branch of medicine which deals with the role of microbial pathogens in human diseases and illnesses.

Pathogen

Any organism that causes diseases in another organism.

Commensal organism

Non-pathogenic member of normal flora that lives on or within another organism without causing harm.

Normal flora

Microorganisms that continuously inhabit the human body under normal circumstances in a healthy individual.

Prokaryotes

Organisms without a true nucleus, including bacteria and archaea.

Eukaryotes

Organisms with a true nucleus, including fungi, protozoa, and helminths.

Eubacteria

All bacteria of medical importance.

Archaebacteria

Unicellular microorganisms that are genetically distinct from bacteria and live in extreme environments.

Fungi

Organisms that include molds and yeasts; characterized by chitin cell walls and non-photosynthetic behavior.

Protozoa

Unicellular eukaryotes that can be motile and include clinically important parasites.

Helminths

Multicellular animal parasites that have microscopic stages in their life cycles.

Viruses

Smallest known infective agents that are obligate intracellular organisms.

Colony formation

Establishment of proliferating microorganisms on the skin or mucous membranes.

Transmission of diseases

Modes through which diseases are spread; includes direct and indirect transmission.

Beneficial effects of normal flora

Include synthesizing and excreting vitamins, preventing pathogen colonization, and stimulating natural antibody production.

Harmful effects of normal flora

Include potential pathogenic behaviors when displaced to abnormal sites and conversion of harmless substances into carcinogenic derivatives.

Antibiotics

Substances that inhibit the growth of or destroy microorganisms, primarily bacteria.

Vaccination

Administration of a vaccine to stimulate an individual's immune response against a specific pathogen.

Infection

A condition caused by the invasion and multiplication of pathogenic microorganisms in the body.

Biofilm

A complex aggregation of microorganisms marked by the secretion of a protective and adhesive matrix.

Immunology

The branch of biomedical science that deals with the study of the immune system.

Pathogenicity

The ability of an organism to cause disease.

Resistance

The ability of microorganisms to withstand the effects of drugs that would normally kill them or inhibit their growth.

Nosocomial Infection

An infection acquired in a hospital or healthcare facility that was not present at the time of admission.

Protozoal Diseases

Diseases caused by protozoa, including malaria and giardiasis.

Public Health Microbiology

The study of microorganisms in the context of public health, focusing on disease prevention and epidemiology.