Haemophilus, Fastidious Gram-Negative Bacilli, Legionella, and Bordetella Flashcards

Vocabulary practice flashcards covering Chapter 18: Haemophilus, HACEK Group, Capnocytophaga, Pasteurella, Brucella, Francisella, Legionella, and Bordetella.

X Factor

Hemin or hematin, a preformed heat-stable growth factor present in blood required by certain Haemophilus species.

V Factor

Nicotinamide adenine dinucleotide (NAD), a heat-labile growth factor present in blood required by certain fastidious bacteria.

Satellitism

A phenomenon where tiny Haemophilus colonies grow around V factor-producing bacteria (e.g., S. aureus) on sheep blood agar.

Polyribitol Phosphate

The unique polymer composed of ribose, ribitol, and phosphate that forms the capsular polysaccharide of Haemophilus influenzae serotype b (Hib).

Nontypable Haemophilus influenzae (NTHi)

Strains of Haemophilus influenzae that lack a polysaccharide capsule and typically cause localized respiratory tract infections.

IgA Protease

An enzyme produced by Haemophilus influenzae that cleaves secretory IgA on human mucosal surfaces.

Epiglottitis

A rapid-onset, life-threatening infection causing severe inflammation and edema of the epiglottis that can lead to complete airway obstruction.

Brazilian Purpuric Fever (BPF)

A severe systemic illness caused by Haemophilus influenzae biogroup aegyptius, characterized by conjunctivitis, high fever, purpural rash, and septicemia.

Chancroid

A highly communicable sexually transmitted genital ulcer disease caused by Haemophilus ducreyi.

Buboes

Suppurative, enlarged, draining regional lymph nodes in the groin associated with chancroid infection.

Soft Chancre

A painful, nonindurated genital lesion with an irregular edge caused by Haemophilus ducreyi.

School of Fish Arrangement

Microscopic appearance of Haemophilus ducreyi cells lined up in parallel or loosely coiled clusters on Gram stain.

Porphyrin Test

An identification method detecting an organism's ability to convert delta-aminolevulinic acid (ALA) into porphyrins or porphobilinogen without needing external X factor.

Delta-Aminolevulinic Acid (ALA)

The primary substrate used in the porphyrin test to evaluate heme biosynthesis capability.

Chromogenic Cephalosporin Test

A rapid assay using a Nitrocefin-impregnated disk that turns red when the beta-lactam ring is cleaved by beta-lactamase.

Acidometric Test

A beta-lactamase detection method utilizing benzylpenicillin and bromcresol purple indicator, turning yellow when penicilloic acid lowers pH.

HACEK Group

An acronym for Haemophilus spp., Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella spp., known for causing endocarditis.

Aggregatibacter aphrophilus

The most prevalent species in the HACEK group involved in endocarditis, found in normal dental plaque and gingival scrapings.

Aggregatibacter actinomycetemcomitans

A fastidious gram-negative coccobacillus associated with juvenile periodontitis and endocarditis, often forming colonies with a star-shaped center.

Cardiobacterium hominis

A fastidious, capnophilic gram-negative bacillus of normal oral biota that forms rosettes on Gram stain and causes endocarditis, especially of the aortic valve.

Eikenella corrodens

An asaccharolytic, oxidase-positive gram-negative bacillus associated with human bite wounds and endocarditis, often pitting agar and producing a bleach-like odor.

Kingella kingae

A beta-hemolytic, oxidase-positive gram-negative coccobacillus with square ends, recognized as a major cause of osteoarthritis in young children.

Kingella denitrificans

An oxidase-positive, catalase-negative organism that ferments glucose, reduces nitrate, and can resemble Neisseria gonorrhoeae on selective media.

Capnocytophaga spp.

Fastidious, fusiform gram-negative bacilli requiring CO2 that produce gliding motility and cause septicemia in neutropenic patients.

Capnocytophaga canimorsus

An oxidase- and catalase-positive species found in dog and cat oral microbiota that causes life-threatening infections after animal bites or saliva exposure.

Pasteurella multocida

A gram-negative, nonmotile, oxidase- and catalase-positive coccobacillus frequently causing wound infections following cat or dog bites.

Bipolar Staining

A staining pattern where the poles of the cell stain more intensely than the center, creating a safety pin appearance.

Pasteurella bettyae

A fastidious, capnophilic, glucose-fermenting coccobacillus isolated from genitourinary specimens, formerly designated CDC group HB-5.

Brucellosis

A zoonotic systemic infection caused by Brucella species, characterized by undulating fevers, night sweats, and fatigue.

Category B Select Biological Agent

Public health classification for pathogens like Brucella spp. that are easy to disseminate and result in moderate morbidity and low mortality.

Undulant Fever

A fever pattern characterized by normal morning body temperatures followed by high temperatures in the afternoon and evening, typical of subchronic brucellosis.

Francisella tularensis

A highly infectious, fastidious gram-negative bacterium requiring cysteine for growth, causing tularemia.

Tularemia

A zoonotic infection also known as rabbit fever or deerfly fever, transmitted via ingestion, inhalation, arthropod bites, or contact with infected animal tissues.

Ulceroglandular Tularemia

The most common clinical form of tularemia, marked by a painful skin ulcer at the inoculation site and regional lymph node enlargement.

Category A Select Biological Agent

Public health classification for high-consequence threat agents like Francisella tularensis that pose a severe risk to public health and safety.

Haemophilus parainfluenzae

A V factor-dependent, nonhemolytic Haemophilus species that forms part of the normal upper respiratory flora.

Haemophilus haemolyticus

A fastidious Haemophilus species requiring both X and V factors that produces beta-hemolysis on horse or rabbit blood agar.

Haemophilus ducreyi

An extremely fastidious human pathogen requiring X factor that causes chancroid and grows optimally at 33°C.

Nairobi Biplate

A biplate containing GC agar with bovine hemoglobin and fetal calf serum on one side and Mueller Hinton with chocolatized horse blood on the other, used to isolate H. ducreyi.

Haemophilus Quad Plate

A four-zone culture plate containing X, V, X+V factors, and horse blood used to differentiate Haemophilus species based on growth requirements and hemolysis.

Dysgonic

A microbiological term describing organisms that grow slowly or poorly on solid culture media.

Capnophilic

Requiring an atmosphere enriched with carbon dioxide (CO2) for optimal bacterial growth.

Gliding Motility

A form of bacterial movement on solid surfaces demonstrated by Capnocytophaga species in the absence of flagella.

Zoonoses

Diseases or infections that are naturally transmitted between vertebrate animals and humans.

Kovacs' Reagent

p-Dimethylaminobenzaldehyde solution added in the porphyrin test to produce a red color if porphobilinogen is present.

Legionnaires' Disease

The severe, pneumonic form of legionellosis characterized by fever, nonproductive cough, pulmonary infiltrates, and systemic symptoms.

Pontiac Fever

A mild, self-limiting, nonpneumonic form of legionellosis characterized by acute flu-like symptoms lasting 2 to 5 days.

Legionella pneumophila

A weakly staining gram-negative bacillus requiring L-cysteine and iron for growth, responsible for the majority of human cases of legionellosis.

L-Cysteine

An essential amino acid required as an additive in culture media (e.g., BCYE) for the primary isolation of Legionella species.

BCYE Agar

Buffered charcoal yeast extract agar, the specialized culture medium essential for the recovery and isolation of Legionella species.

Ground-Glass Appearance

The characteristic light gray, granular central morphology of young Legionella colonies viewed under a dissecting microscope.

Urine Antigen Test for Legionella

A rapid assay detecting soluble Legionella pneumophila serogroup 1 antigen in urine specimens.

Direct Fluorescent Antibody (DFA) Test for Legionella

A microscopic procedure using fluorescein-labeled antibodies to detect Legionella cells directly in clinical samples.

Atypical Pneumonia

Pneumonia caused by pathogens such as Legionella, Mycoplasma, or Chlamydophila that present differently from classic pneumococcal pneumonia.

Legionella micdadei

A Legionella species causing pneumonia that is weakly acid-fast in tissue and stains positive with the modified Kinyoun procedure.

Legionella longbeachae

A Legionella species causing human illness associated with exposure to gardening compost and potting soil.

Legionella dumoffii

A clinically significant Legionella species whose colonies exhibit blue-white autofluorescence under long-wave UV light.

Autofluoresence

Emission of colored light (yellow-green or blue-white) when Legionella colonies on BCYE are exposed to long-wave UV light (366 nm).

KCl-HCl Acid Treatment

A processing method involving a 1:10 dilution in 0.2 N KCl-HCl used to reduce contaminating normal biota before inoculating Legionella cultures.

Indirect Fluorescent Antibody (IFA) Assay

A serologic test measuring patient antibody titers to detect recent Legionella infection by demonstrating a fourfold rise in titer.

Bordetella pertussis

A fastidious, obligate aerobic gram-negative coccobacillus that causes pertussis (whooping cough) in humans.

Whooping Cough

A highly contagious acute respiratory tract infection caused by Bordetella pertussis, characterized by severe paroxysmal coughing fits.

Catarrhal Phase

The initial stage of pertussis characterized by mild, nonspecific respiratory symptoms and maximum bacterial shedding.

Paroxysmal Phase

The second stage of pertussis marked by sudden, repetitive coughing spells ending with a characteristic inspiratory whoop.

Convalescent Phase

The recovery stage of pertussis beginning around 4 weeks after onset, marked by gradual reduction in coughing frequency and severity.

Filamentous Hemagglutinin (FHA)

A surface protein of Bordetella pertussis that mediates adherence to ciliated respiratory epithelial cells.

Pertussis Toxin (PT)

A protein exotoxin produced by Bordetella pertussis that ADP-ribosylates host cell proteins and disrupts signal transduction.

Tracheal Cytotoxin

An exotoxin produced by Bordetella pertussis that causes destruction of ciliated respiratory cells, ciliostasis, and cell death.

Adenylate Cyclase Toxin

A Bordetella pertussis toxin that increases intracellular cyclic AMP levels, inhibiting host immune effector cells and respiratory epithelium.

Pertactin

A 69-kDa outer membrane protein of Bordetella pertussis that facilitates bacterial attachment to host cells.

Bordet-Gengou Potato Infusion Agar

An isolation medium containing potato infusion, glycerol, and blood used for cultivating Bordetella pertussis.

Regan-Lowe Transport Medium

A transport medium consisting of half-strength charcoal agar supplemented with 10% horse blood and cephalexin for Bordetella recovery.

Mercury Droplet Colony Morphology

Description of young Bordetella pertussis colonies appearing smooth, glistening, elevated, and silver on charcoal agar.

Bordetella parapertussis

A species causing a milder pertussis-like illness that produces urease within 24 hours and grows on blood agar.

Bordetella bronchiseptica

An oxidase- and urease-positive pathogen that causes kennel cough in animals and opportunistic respiratory disease in humans.

Acellular Pertussis (aP) Vaccine

A subunit vaccine composed of purified Bordetella pertussis antigens, administered in combination with diphtheria and tetanus toxoids.

Flocked Swabs

Swabs with short nylon fibers sprayed onto a tip, providing improved collection and release of fastidious respiratory pathogens like Bordetella.

Inspiratory Whoop

The high-pitched sound made when a patient rapidly inhales air at the conclusion of a paroxysmal coughing spell.

Posttussive Vomiting

Vomiting that occurs immediately following a violent fit of coughing, a classic sign of the paroxysmal phase of pertussis.

Ciliostasis

The loss of normal sweeping motility of respiratory tract cilia, caused by tracheal cytotoxin during pertussis.

Cephalexin

An antibiotic selective agent added to Bordetella media at 40 mg/L to suppress normal upper respiratory microbiota.

Nitrocefin

A chromogenic cephalosporin substrate that turns from yellow to red upon hydrolysis by bacterial beta-lactamase enzymes.

Bacitracin Supplemented Chocolate Agar

Selective medium containing 300 mg/L bacitracin used to isolate Haemophilus species from respiratory samples by inhibiting normal biota.

IsoVitaleX

A chemically defined enrichment supplement containing vitamins and nutrients added to chocolate agar to support growth of fastidious pathogens.

Koch-Weeks Bacillus

The historical name assigned to Haemophilus aegyptius, the cause of epidemic acute contagious conjunctivitis.

Haemophilus influenzae biogroup aegyptius

A clone of nonencapsulated H. influenzae that causes conjunctivitis and Brazilian Purpuric Fever.

Clenched Fist Wounds

Traumatic soft tissue hand injuries resulting from striking human teeth, frequently infected with Eikenella corrodens.

Asaccharolytic

Inability to metabolize carbohydrates through either fermentation or oxidation, a trait exhibited by Eikenella corrodens.

Rosette Formation

The characteristic microscopic grouping of Cardiobacterium hominis cells forming rose-like clusters or radial arrangements on Gram stain.

Fusiform Bacilli

Bacterial cells with long, thin bodies and sharply pointed ends, typical of Capnocytophaga microscopic morphology.

Brucella melitensis

A species of Brucella whose natural hosts are goats and sheep, frequently implicated in severe human brucellosis.

Brucella abortus

A Brucella species whose primary hosts are cattle, requiring added CO2 for growth and producing H2S.

Brucella suis

A swine-associated Brucella species that rapidly hydrolyzes urea in under 30 minutes and produces H2S.

Brucella canis

A Brucella species hosted by dogs that is negative for serum agglutination tests using standard patient antibodies.

Francisella tularensis subsp. tularensis

Type A strain of F. tularensis, found in North America, causing the most severe and highly fatal forms of tularemia.

Francisella tularensis subsp. holarctica

Type B strain of F. tularensis, widely distributed in the Northern Hemisphere, causing milder forms of tularemia.

Cysteine Supplementation

Addition of cysteine or cystine to culture media, strictly required for the growth of Francisella tularensis.

Acridine Orange Stain

A fluorochrome stain useful for detecting faintly staining, pleomorphic gram-negative bacilli like Haemophilus in direct smears.

Bordetella holmesii

An opportunistic Bordetella species isolated from the blood of immunocompromised patients and occasionally from patients with pertussis-like symptoms.

Bordetella trematum

A Bordetella species described as an agent of human wound and ear infections.