Aerobic Gram-Positive Bacilli and Nonfermentative Gram-Negative Rods Vocabulary

A comprehensive collection of 100 vocabulary flashcards covering aerobic gram-positive bacilli (Corynebacterium, Listeria, Erysipelothrix, Arcanobacterium, Gardnerella, Nocardia, Bacillus) and non-fermentative gram-negative bacilli (Pseudomonas, Burkholderia, Stenotrophomonas, Acinetobacter, Moraxella).

Diphtheroid

A descriptive term for slightly curved gram-positive rods with unparallel sides and club-shaped ends resembling Corynebacterium diphtheriae.

Diphtheria toxin

A potent protein exotoxin of $62,000\,\text{Da}$ produced by lysogenized strains of C. diphtheriae that inhibits eukaryotic protein synthesis.

Fragment A (Diphtheria toxin)

The enzymatic subunit of diphtheria toxin that cleaves nicotinamide adenosine dinucleotide and inactivates elongation factor 2 ($\text{EF-2}$).

Fragment B (Diphtheria toxin)

The receptor-binding subunit of diphtheria toxin that mediates entry of Fragment A into the cytoplasm of host cells.

Babès-Ernst granules

Metachromatic intracellular granules composed of polymerized polyphosphates that accumulate as nutrient reserves in Corynebacterium species.

Loeffler medium

An enriched culture medium containing serum used to cultivate Corynebacterium spp. and demonstrate characteristic microscopic pleomorphism.

Cystine-tellurite blood agar (CTBA)

A selective and differential medium containing potassium tellurite on which Corynebacterium spp. reduce tellurite to form black or brownish colonies.

Elek test

An in vitro immunodiffusion assay used to detect diphtheria toxin production using an antitoxin-impregnated filter paper strip.

Arch of identity

The joined precipitation arc formed in an Elek test between the toxin line of a positive control and that of a toxigenic test strain.

Corynebacterium amycolatum

The most frequently recovered Corynebacterium species from human clinical specimens, featuring flat, dry, nonlipophilic colonies with matte appearance.

Corynebacterium jeikeium

A lipophilic, strict aerobe skin commensal resistant to multiple antimicrobials, frequently causing endocarditis and catheter infections.

Corynebacterium pseudodiphtheriticum

A nasopharyngeal commensal that forms non-pleomorphic palisades, reduces nitrate, and hydrolyzes urea, causing respiratory infections.

Corynebacterium pseudotuberculosis

A veterinary pathogen that produces urease, forms a brown halo on CTBA, and causes granulomatous lymphadenitis in humans.

Corynebacterium striatum

A nonlipophilic pleomorphic organism part of normal skin biota that causes nosocomial device-related infections and endocarditis.

Corynebacterium ulcerans

A urease-positive veterinary pathogen isolated from skin ulcers and exudative pharyngitis that can produce diphtheria toxin.

Corynebacterium urealyticum

A lipophilic, strict aerobe urinary pathogen that yields nonhemolytic pinpoint colonies and turns Christensen urea slants positive within minutes.

Rothia dentocariosa

An oropharyngeal inhabitant that forms short rods or branching filaments on solid media and coccoid cells in broth.

Rothia mucilaginosa

A gram-positive micrococcal organism linked to bacteremia, endocarditis, and pneumonia in immunocompromised hosts.

Listeria monocytogenes

A gram-positive, catalase-positive, motile coccobacillus that causes listeriosis in newborns, pregnant women, and immunocompromised adults.

Listeriolysin O

A major hemolysin virulence factor of L. monocytogenes that disrupts phagosomal membranes to prevent macrophage destruction.

Protein p60

A surface protein of Listeria monocytogenes that promotes cell adhesion and entry into mammalian target cells.

Cold enrichment

A prolonged isolation technique involving specimen incubation in broth at $4^\circ\text{C}$ to selectively isolate organisms like Listeria monocytogenes.

Tumbling motility

The end-over-end motility pattern displayed by Listeria monocytogenes when examined in wet mount preparations at room temperature.

Umbrella motility

The characteristic growth pattern produced by Listeria monocytogenes near the surface of motility media incubated at $22^\circ\text{C}$ to $25^\circ\text{C}$.

Early-onset neonatal listeriosis

An intrauterine Listeria infection presenting at or shortly after birth as severe sepsis, often associated with amniotic fluid aspiration.

Late-onset neonatal listeriosis

Listeria infection manifesting several days to weeks after birth in full-term infants, predominantly presenting as meningitis.

Erysipelothrix rhusiopathiae

A gram-positive, catalase-negative, non-spore-forming pleomorphic rod that produces $\text{H}_2\text{S}$ on TSI and forms long filaments.

Erysipeloid

A localized, painful, elevated purplish-red cutaneous infection caused by occupational inoculation of Erysipelothrix rhusiopathiae.

Test tube brush-like pattern

The characteristic sub-surface lateral outgrowth formed by Erysipelothrix rhusiopathiae in gelatin stab cultures incubated at $22^\circ\text{C}$.

Arcanobacterium haemolyticum

A catalase-negative, lipase-positive rod causing pharyngitis with rash in young adults that exhibits a reverse CAMP reaction.

Reverse CAMP reaction

Inhibition of Staphylococcus aureus \beta-lysin hemolysis mediated by phospholipase D produced by Arcanobacterium haemolyticum.

Gardnerella vaginalis

A pleomorphic, gram-variable, catalase-negative coccobacillus that hydrolyzes hippurate and is associated with bacterial vaginosis.

Bacterial vaginosis

A polymicrobial vaginal condition caused by a decrease in Lactobacillus and overgrowth of Gardnerella vaginalis and anaerobes.

Clue cells

Large vaginal squamous epithelial cells densely coated with gram-variable coccobacilli along their borders.

Nugent scoring system

A standardized diagnostic score ($0$ to $10$) evaluating bacterial morphotypes on Gram-stained vaginal smears to diagnose bacterial vaginosis.

Human blood bilayer Tween (HBT) agar

A selective differential medium containing human blood used to isolate Gardnerella vaginalis, which forms \beta-hemolytic colonies.

Nocardia

A genus of aerobic, branched, beaded, gram-positive, partially acid-fast bacilli commonly found in soil.

Modified acid-fast stain

A staining procedure employing a weak acid ($0.5\%$ to $1.0\%$ sulfuric acid) decolorizer to detect partially acid-fast bacteria.

Actinomycotic mycetoma

A chronic, suppurative subcutaneous infection with draining sinuses and granules caused by aerobic actinomycetes such as Nocardia brasiliensis.

Eumycotic mycetoma

A destructive subcutaneous infection caused by true fungi, containing broad septate hyphae ($2$ to $5\,\mu\text{m}$) within granules.

Sulfur granules

Macroscopic yellow or orange granular aggregates of filamentous microorganisms bound by host material, found in mycetoma pus.

Nocobactin

An iron-chelating compound synthesized by Nocardia species whose concentration directly correlates with bacterial virulence.

Nocardia brasiliensis

The primary etiologic agent of cutaneous nocardiosis and actinomycotic mycetoma, usually acquired through skin trauma.

Nocardia cyriacigeorgica

A major Nocardia species responsible for confluent, necrotizing bronchopneumonia and pulmonary nocardiosis.

Nocardia farcinica

A virulent Nocardia species causing severe pulmonary infections and dissemination to the brain to form abscesses.

Actinomadura madurae

An aerobic actinomycete agent of mycetoma that ferments cellobiose and xylose, distinguishing it from Nocardia species.

Streptomyces somaliensis

A soil-dwelling aerobic actinomycete with extensive filamentous branching that causes actinomycotic mycetoma.

Gordonia

A genus of aerobic, partially acid-fast nocardioform bacilli that reduce nitrate and fragment from mycelia into short rods.

Tsukamurella

Aerobic, partially acid-fast long bacilli without aerial hyphae that cause catheter-related bacteremia and pulmonary infections.

Rhodococcus equi

A partially acid-fast diphtheroid organism producing salmon-pink mucoid colonies on SBA, causing lung infections in AIDS patients.

Tropheryma whipplei

An intracellular gram-positive actinomycete detected in tissue macrophages that serves as the causative agent of Whipple's disease.

Whipple's disease

A fatal systemic infection causing diarrhea, weight loss, abdominal pain, and arthralgia, diagnosed by PAS-positive macrophages.

Bacillus

A genus of aerobic or facultatively anaerobic, catalase-positive, endospore-forming gram-positive or gram-variable bacilli.

Bacillus anthracis

A large, square-ended, non-motile, non-hemolytic, encapsulated gram-positive rod that serves as the etiologic agent of anthrax.

Bamboo rod appearance

The characteristic microscopic chain arrangement of Bacillus anthracis created by square-ended vegetative cells with central spores.

Protective antigen (PA)

The binding subunit of anthrax toxin that attaches to host cell receptors to permit entry of Edema Factor and Lethal Factor.

Edema factor (EF)

An adenylate cyclase exotoxin component of Bacillus anthracis that raises intracellular cAMP, resulting in tissue edema.

Lethal factor (LF)

A zinc metalloprotease toxin component of Bacillus anthracis that cleaves cell signaling molecules, causing host cell death.

Cutaneous anthrax

The most common form of anthrax, presenting as a painless papule that develops into a ring of vesicles and a black eschar.

Eschar

A depressed, black, necrotic central wound lesion surrounded by edema, characteristic of cutaneous anthrax infection.

Inhalation anthrax

A severe form of anthrax caused by inhaling spores, leading to respiratory distress, pleural effusions, and rapid mortality.

Gastrointestinal anthrax

A rare anthrax infection caused by ingesting spore-tainted meat, manifesting with abdominal pain, vomiting, and bloody diarrhea.

Injectional anthrax

A severe soft-tissue anthrax infection without eschar formation, associated with direct spore injection from illicit drug use.

Medusa head colony

A descriptive term for flat, gray Bacillus anthracis colonies with irregular margins formed by outgrowths of long filamentous bacterial chains.

String of pearls reaction

The microscopic conversion of Bacillus anthracis vegetative cells into spherical chains when incubated on agar with penicillin.

Bacillus cereus

A motile, \beta-hemolytic, penicillin-resistant spore-forming bacillus that causes emetic and diarrheal food poisoning and ocular infections.

Emetic enterotoxin

A low-molecular-weight ($<5000\,\text{Da}$), heat-stable toxin produced by B. cereus that induces nausea and vomiting within $1$ to $5\text{ hours}$.

Diarrheal enterotoxin

A heat-labile toxin ($\sim 50,000\,\text{Da}$) produced by B. cereus that activates adenylate cyclase, causing diarrhea within $8$ to $16\text{ hours}$.

Parasporal crystals

Protein inclusions produced during sporulation by Bacillus thuringiensis that function as biological insecticides.

Pseudomonas aeruginosa

An obligate aerobic, oxidase-positive, non-fermentative gram-negative rod that produces pyocyanin/pyoverdin and causes opportunistic infections.

Exotoxin A (ETA)

The major exotoxin of Pseudomonas aeruginosa that halts eukaryotic protein synthesis by blocking peptide chain elongation.

Pyocyanin

A blue phenazine pigment produced by Pseudomonas aeruginosa that catalyzes toxic oxygen radicals and stimulates interleukin-8 release.

Pyoverdin

A yellow-green fluorescent siderophore produced by Pseudomonas aeruginosa that binds environmental iron for bacterial growth.

Alginate

A mucoid exopolysaccharide capsule produced by Pseudomonas aeruginosa strains colonizing the lungs of cystic fibrosis patients.

LasA and LasB elastases

Serine and zinc metalloproteases secreted by Pseudomonas aeruginosa that degrade host elastin, tissues, and complement components.

Ecthyma gangrenosum

Hemorrhagic, necrotic cutaneous ulcers caused by vascular invasion during disseminated Pseudomonas aeruginosa septicemia in neutropenic hosts.

Exoenzymes S and T

Effector toxins injected into target host cytoplasm by the P. aeruginosa type III secretion system that reorganize actin filaments.

External otitis

A localized infection of the outer ear canal commonly caused by Pseudomonas aeruginosa after exposure to contaminated water.

Malignant external otitis

An invasive, life-threatening Pseudomonas aeruginosa infection destroying adjacent cranial bones, seen primarily in elderly diabetic patients.

Osteochondritis of the foot

Inflammation of bone and cartilage caused by Pseudomonas aeruginosa after a puncture wound through a damp sneaker.

Quorum sensing

A density-dependent cell signaling mechanism used by Pseudomonas aeruginosa to regulate virulence factors and biofilm formation.

Burkholderia cepacia complex

A group of 17 non-fermentative species causing necrotizing pulmonary infections in patients with cystic fibrosis or chronic granulomatous disease.

Burkholderia pseudomallei

An environmental saprophyte endemic to Southeast Asia and Australia that serves as the causative agent of melioidosis.

Melioidosis

A disease caused by Burkholderia pseudomallei ranging from localized suppurative cutaneous lesions and pneumonia to fatal septicemia.

Burkholderia mallei

A non-motile bacterial pathogen closely related to B. pseudomallei that causes glanders in equines and humans.

Stenotrophomonas maltophilia

An opportunistic, oxidase-negative, non-fermentative rod intrinsically resistant to carbapenems and susceptible to trimethoprim-sulfamethoxazole.

Acinetobacter baumannii

A strictly aerobic, oxidase-negative, plump gram-negative coccobacillus responsible for multidrug-resistant nosocomial infections.

Moraxella catarrhalis

A strictly aerobic, oxidase-positive, gram-negative diplococcus that produces \beta-lactamases and causes otitis media and sinusitis.

Type III secretion system

A molecular syringe mechanism utilized by P. aeruginosa to directly inject bacterial effector toxins into host cell cytoplasm.

Chronic granulomatous disease (CGD)

A primary immunodeficiency characterized by defective phagocyte microbicidal activity, predisposing patients to Burkholderia infections.

Heteroresistance

The presence of a highly resistant subpopulation of cells within an isolate that tests susceptible in standard in vitro testing.

AmpC gene

An inducible chromosomal gene in Pseudomonas aeruginosa that expresses \beta-lactamase upon exposure to drugs like ceftazidime.

Spore stain

A differential staining technique where vegetative bacterial cells stain red and endospores stain green.

Efflux pumps

Bacterial membrane transport mechanisms that actively expel antibiotics, contributing to intrinsic and acquired drug resistance.

Pseudomonas folliculitis

A pruritic papular and pustular skin infection resulting from exposure to P. aeruginosa in contaminated hot tubs or pools.

Biofilm

An enclosed microbial community embedded within a self-produced matrix on catheters or lung tissue that protects cells from antibiotics.

Trimethoprim-sulfamethoxazole (TMP-SMX)

The primary drug of choice for treating infections caused by Stenotrophomonas maltophilia and Burkholderia cepacia complex.

Vancomycin

The drug of choice for treating severe multidrug-resistant Corynebacterium jeikeium and Corynebacterium urealyticum infections.

Ciprofloxacin

A fluoroquinolone antimicrobial agent recommended for postexposure prophylaxis and combination treatment of Bacillus anthracis.

Metronidazole

The primary recommended therapeutic agent for treating bacterial vaginosis associated with Gardnerella vaginalis.