CHSE Odisha Voc. Microbiology & Serology key terms

An infection a patient acquires during a hospital stay that was not present or incubating at the time of admission, often caused by resistant organisms and spread through hands, equipment, or procedures.

Routine infection-control practices applied to every patient, including hand hygiene, gloves, gowns, masks, safe sharps handling, and safe waste disposal, regardless of whether infection is suspected.

Sorting laboratory and clinical waste at the point of generation into colour-coded categories such as infectious, sharps, and chemical waste so each stream is handled and disposed of safely.

An enclosed ventilated workbench that uses HEPA-filtered airflow to protect the worker, the sample, and the environment from aerosols generated while handling infectious material.

A suspension of fine liquid or solid particles in air, produced by pipetting, centrifuging, or opening tubes, which can carry microorganisms into the breathing zone of laboratory staff.

A measure of how much a medium slows and bends light passing through it; matching immersion oil to glass increases resolution by preventing light loss at the objective lens.

A number describing the light-gathering ability of a lens, equal to the refractive index of the medium times the sine of the half-angle of light acceptance; higher values give better resolution.

The smallest distance at which two closely spaced points can still be seen as separate; for a light microscope it is limited by wavelength and numerical aperture to about 0.2 micrometre.

A high-magnification lens, usually 100x, designed to be used with a drop of immersion oil that replaces air between lens and slide, raising numerical aperture and improving resolution.

A staining method using more than one dye so that different organisms or cell structures take up different colours, allowing them to be distinguished under the microscope.

A differential stain in which crystal violet and iodine form a complex retained by thick peptidoglycan cell walls, while thin-walled cells decolourise and take the red counterstain.

A stain using heat or strong solvent with carbol fuchsin so that waxy mycolic-acid-rich cell walls retain the red dye and resist decolourisation, while other bacteria stain blue.

A pressure vessel that sterilises equipment and media using saturated steam at raised pressure, typically 121 degrees Celsius for 15 minutes, killing spores by moist heat.

The complete destruction or removal of all viable microorganisms, including bacterial endospores and viruses, from an object, medium, or surface.

The destruction or inactivation of most pathogenic microorganisms on inanimate surfaces or in liquids, without necessarily killing all spores or all non-pathogenic organisms.

A chemical agent applied to living tissue such as skin or mucous membrane to reduce or kill microorganisms, chosen for low toxicity to host cells.

The lowest temperature at which a standard suspension of microorganisms is killed within a fixed time, usually ten minutes, under defined conditions.

The mesh-like polymer of alternating sugar chains cross-linked by short peptides that forms the main structural layer of bacterial cell walls and determines Gram reaction.

A dormant, highly resistant structure formed inside certain Gram-positive bacteria such as Bacillus and Clostridium, surviving heat, drying, and chemicals until conditions allow germination.

The interval required for a microbial population to double in number during exponential growth, varying with species, nutrients, temperature, and other environmental conditions.

The pattern of population size over time in a closed culture, showing lag, exponential, stationary, and decline phases as nutrients are consumed and waste products accumulate.

A unit used to report viable counts, where one colony on a plate may arise from a single cell or from a clump of attached cells.

The lowest concentration of an antimicrobial agent that prevents visible growth of a microorganism in a standardised susceptibility test such as broth dilution.

The ability of a microorganism to survive and multiply in the presence of an antimicrobial agent that would normally inhibit or kill it, arising by mutation or acquired resistance genes.

A substance produced by or derived from a microorganism that inhibits or kills other microorganisms, though the term now includes many synthetic and semi-synthetic compounds.

A ratio comparing the killing power of a disinfectant with that of phenol under standard test conditions, where values above one indicate greater effectiveness than phenol.

The process by which cells such as neutrophils and macrophages engulf particles or microorganisms into vesicles and destroy them using enzymes and reactive oxygen species.

A molecule, such as antibody or complement fragment, that coats a microorganism and makes it easier for phagocytes to bind and ingest it.

A group of serum proteins that act in sequence to coat microbes, attract phagocytes, and puncture membranes, forming part of innate and antibody-dependent immune defence.

A local response to injury or infection marked by redness, heat, swelling, pain, and loss of function, bringing immune cells and plasma proteins to the affected site.

Any substance that can be specifically recognised and bound by an antibody or T-cell receptor and can provoke an adaptive immune response when suitably presented.

The small specific part of an antigen that is actually bound by one antibody combining site or T-cell receptor, often only a few amino acids or sugar residues.

An immunoglobulin protein produced by plasma cells that binds a specific antigen through variable regions and helps neutralise, opsonise, or eliminate the target.

Antibody molecules of a single specificity produced by one clone of cells, widely used in diagnostic tests because they bind one epitope consistently.

A serological reaction in which antibodies cross-link particulate antigens such as bacterial cells into visible clumps, used for blood grouping and bacterial identification.

The highest dilution of a serum sample at which a defined reaction, such as agglutination, is still visible, giving a measure of antibody concentration.

A plate-based immunoassay in which an enzyme linked to an antibody or antigen produces a colour change proportional to the amount of target present.

A long-chain fatty acid found in the cell walls of mycobacteria, making them waxy, acid-fast, slow-growing, and relatively resistant to many disinfectants and antibiotics.

A toxic protein released by living bacteria, often heat-labile and highly specific in its action, commonly produced by organisms such as Clostridium and Staphylococcus.

A culture medium containing substances that suppress the growth of unwanted organisms while allowing the target organisms to grow, aiding isolation from mixed samples.

A liquid culture step designed to increase the numbers of a particular organism, often a pathogen present in small numbers, before plating onto solid media.

A statistical estimate of bacterial density in water or food obtained from the pattern of positive tubes in a dilution series, commonly used for coliform assessment.

A group of Gram-negative, lactose-fermenting, rod-shaped bacteria whose presence in water or food indicates possible faecal contamination and inadequate hygiene.

A microorganism whose presence or level is monitored to signal contamination or process failure, such as coliforms for water quality or Escherichia coli for faecal pollution.