Microbiology Lecture Review: Unclassified Bacteria Flashcards

A set of vocabulary-style flashcards covering the morphology, taxonomy, clinical presentations, and diagnostics for Chlamydia, Mycoplasma, and Rickettsiae based on lecture notes.

Pleomorphic

The ability of a microorganism, such as Chlamydia or Rickettsia, to assume different forms; also referred to as polymorphic bacteria.

Tropism

The turning of all or part of an organism in a particular direction in response to an external stimulus, such as the affinity of Chlamydia for non-ciliated columnar epithelial cells.

Chlamydia precurom

One of the four species comprising the Genus Chlamydia, alongside C. trachomatis, C. psitacci, and C. pneumoniae.

Elementary Body (EB)

An environmentally stable, metabolically inert infectious particle measuring $0.2-0.4\,\mu m$ in diameter; it is responsible for attachment and entry into host cells.

Reticulate Body (RB)

Also called the 'initial body,' this is the metabolically active intracellular form of Chlamydia, measuring $0.5-1.0\,\mu m$, which divides by binary fission.

Energy parasites

Organisms, such as Chlamydiae or Rickettsiae, that rely on the host cell for their energy needs because they are unable to produce high-energy compounds like ATP.

MOMP (Major Outer Membrane Protein)

A transmembrane protein in the Chlamydia cell wall that contains species-specific and subspecies-specific epitopes defined by monoclonal antibodies.

Hemagglutinin

A group of glycoproteins that cause red blood cells to agglutinate and are responsible for the binding of viruses or microorganisms to cell surface receptors.

Phagocytosis

The process of 'cell eating' involving the ingestion of large particles, such as bacteria, into a cell via vesicles.

Cicatrization

The scarring of the eyelid due to recurrent Chlamydia infection, which can distort the lid margin and lead to entropion and trichiasis.

Pannus

An abnormal condition of the cornea seen in trachoma where it becomes vascularized and infiltrated with granular tissue just beneath the surface.

Entropion

A medical condition in which the eyelid, usually the lower one, turns inward so that the eyelashes rub against the eyeball.

Trichiasis

Abnormally positioned eyelashes that grow back toward the eye, touching the cornea or conjunctiva; it is the leading cause of infectious blindness.

Biovar

A biological variant within a bacterial species distinguished from other strains based on physiological or biochemical differences.

Serotype (Serovar)

A subgroup of a bacterial species distinguished by unique surface antigens identified using antibody reactions.

Lymphogranuloma venereum (LGV)

A sexually transmitted infection caused by C. trachomatis serotypes L1, L2, L2a, L2b, and L3, characterized by inguinal buboes and potential anorectal involvement.

Fistula

An abnormal tunnel or connection between two body parts, such as between an internal organ and the skin surface.

Buboes

Painful, enlarged, and fluctuant lymph nodes that may rupture, forming draining fistulas; characteristic of the secondary stage of LGV.

Esthiomene

A condition in the third stage of untreated LGV where the vulva, scrotum, or penis undergoes edematous granulomatous hypertrophy.

Halberstaedter – Prowazek bodies

Inclusion bodies seen on the epithelial cells of the conjunctiva in cases of adult inclusion conjunctivitis.

Fitz-Hugh-Curtis Syndrome

A rare condition in females characterized by perihepatitis and 'violin-string' adhesions, often as a complication of pelvic inflammatory disease caused by Neisseria gonorrhoeae or Chlamydia trachomatis.

Reiter's syndrome

Also known as reactive arthritis, it is a clinical triad of conjunctivitis, urethritis, and arthritis occurring after a urogenital or gastrointestinal infection.

Frei’s skin test

An intradermal skin test for LGV where a positive reaction is marked by a nodule $> 5\,mm$ or an inflammatory macule measuring $7\,mm$ in diameter after $2-4$ days.

TWAR strain

The original name for Chlamydophila pneumoniae, derived from Taiwan (TW-183) and an acute respiratory isolate (AR-39).

Horder’s spots

Pink blanching maculopapular eruptions resembling the rose spots of typhoid fever, which sometimes appear during the first week of psittacosis.

Levinthal-Cole-Lille (LCL) inclusion bodies

Inclusion bodies found in C. psittaci infections that are not stained by iodine and are more diffused and irregular than other chlamydial inclusions.

Mollicutes

A class of bacteria, including Mycoplasma, distinguished by the complete absence of a cell wall and a genome as small as $577-2200\,kb$.

Eaton’s agent

The historical name for Mycoplasma pneumoniae, discovered in 1944 as the agent causing primary atypical pneumonia.

Fried egg appearance

The characteristic look of Mycoplasma colonies on agar, where the center is embedded beneath the surface.

Weil-Felix reaction

A presumptive serological test for rickettsial infections using Proteus strains OX2, OX19, and OXK based on shared antigenic cross-reactivity.

Brill-Zinsser disease

A relapsing, milder form of louse-borne epidemic typhus caused by the reactivation of Rickettsia prowazekii after lying dormant.

Angiitis

Inflammation of the blood vessels, also known as vasculitis, which is the primary pathology in rickettsial diseases.

Musca sorbens

Known as the 'Bazaar Fly,' this insect vector feeds on ocular and nasal discharges and is a primary route for transmitting trachoma.