(F) Lesson 12: Haemophilus and Other Fastidious Bacteria (Part 2) Flashcards by Kchianna Lauren Coronel

Composed of Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella
Most are part of the normal biota of the oral cavity and URT
All are related to bacterial endocarditis
Fastidious, facultative anaerobes, enhanced growth under presence of CO2

HACEK group

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ACEK are ____ which means slower or poorer growing.

Dysgonic

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T or F: The HACEK group includes those with immunocompromised state or those that are called as opportunistic pathogen.

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The HACEK group are related to bacterial endocarditis due to their?

Predilection for attachment to heart valves

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Familiarize yourself with the risk of infection for the HACEK group.

Tooth extraction
History of endocarditis
Gingival surgery
Heart valve surgery
Mitral valve prolapse

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Comes from the Greek words aphros and philia which means foam-loving or desiring high concentration of CO2
Found in dental plaque and gingival scraping
Reclassification of H. aphrophilus and H. paraphrophilus due to molecular techniques

Aggregatibacter aphrophilus

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Formerly part of actinobacillus
Divided into 6 serotypes: A to F
Etiologic pathogen for periodontitis
Has two major virulence factors: collagenase and leukotoxin

Aggregatibacter actinomycetemcomitans

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Aggregatibacter actinomycetemcomitans

These serotypes (3) are the most common causative agents of infection.

A, B, C

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Aggregatibacter actinomycetemcomitans

This virulence factor is for the destruction of collagen.

Collagenase

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Aggregatibacter actinomycetemcomitans

This virulence factor is against WBCs and has something to do with anti-phagocytosis.

Leukotoxin

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Colony of Aggregatibacter actinomycetemcomitans after 48 hours?

Star-shape with 4 to 6 points

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T or F: The colony of Aggregatibacter actinomycetemcomitans may be observed with the naked eye.

F (use a microscope or stereomicroscope in LPO or scanner)

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Drug of choice for Aggregatibacter actinomycetemcomitans?

Penicillin and an aminoglycoside (combined)

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Alternative drugs for Aggregatibacter actinomycetemcomitans?

Third generation cephalosporins
Quinolones
Chloramphenicol
Tetracycline

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Resistance of Aggregatibacter actinomycetemcomitans to ____ and ____ common.

Vancomycin and erythromycin

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What are the two species of Cardiobacterium?

Cardiobacterium hominis
Cardiobacterium valvarum

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Which Cardiobacterium spp. is more related to bacterial endocarditis?

Cardiobacterium hominis

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Part of the normal biota
Has agar pitting
Infects the aortic valve more than other HACEK members

Cardiobacterium hominis

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Drug of choice for Cardiobacterium hominis?

Penicillin with an aminoglycoside

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Cardiobacterium hominis is sensitive to what drugs?

Beta-lactam antibiotics
Chloramphenicol
Tetracycline

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Cardiobacterium hominis has a variable response to what drugs?

Aminoglycosides
Erythromycin
Clindamycin
Vancomycin

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Part of the normal biota
Associated with human bites or fights (clenched fist wounds)
Opportunistic to immunocompromised individuals, producing periodontitis, meningitis, empyema, pneumonia, osteomyelitis, arthritis, and postoperative tissue infections
The least common isolate among the HACEK group for endocarditis
Called this because of corrosion seen in its agar pitting and yellow pigment

Eikenella corrodens

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Eikenella corrodens is sensitive to what drugs?

Penicillin
Ampicillin
Cefoxitin
Chloramphenicol
Carbenicillin
Imipenem

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Eikenella corrodens is resistant to what drugs?

Clindamycin and other narrow-spectrum cephalosporin

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* It resists in decolorization in G/S, appearing as G(+) * Major G(-) bacterium isolated from **degenerative joint and bone infections (osteoarthritis)** in children

Kingella kingae

What are the four members of the Kingella species?

* Kingella kingae * Kingella denitrificans * Kingella oralis * Kingella potus

Which member of the Kingella species is related to endocarditis?

Kingella kingae

Kingella kingae's ability to resist decolorizatuon is **not due** to what?

Peptidoglycan layer

Color of the colonies of Kingella kingae?

Yellow brown

T or F: Kingella kingae is resistant to most agents, including penicillin.

F *(susceptible)*

The five (5) identified species of Capnocytophaga spp. that are part of the oral microbiota

* Capnocytophaga ochracea * Capnocytophaga gingivalis * Capnocytophaga sputigena * Capnocytophaga haemolyticus * Capnocytophaga granulosa

This species of Capnocytophaga spp. is the only one that tests **negative for oxidase and catalse.**

Capnocytophaga granulosa

* Not as commonly involved in endocarditis as they are in septicemia * G/S: **thin and often fusiform (pointed ends)** resembling Fusobacterium spp. * Motile organisms with a **gliding motility** * On the agar: **yellow-orange**

Capnocytophaga spp.

* **Positive for:** Sucrose, glucose, maltose, lactose, nitrite, and esculin * **No growth** on TSI without enrinchment * **Non-hemolytic**

Capnocytophaga spp.

This is the only **beta-hemolytic** organism from Capnocytophaga spp.

Capnocytophaga haemolytica

# Capnocytophaga spp. The two **zoonotic** species found in the cat/dog oral cavity from bite wounds.

* Capnocytophaga canimorsus * Capnocytophaga cynodegmi

Drug of choice for Capnocytophaga canimorsus and Capnocytophaga cynodegmi?

Penicillin

The Capnocytophaga spp. are **susceptible** to what drugs?

* Imipenem * Erythromycin * Clindamycin * Tetracycline * Chloramphenicol * Quinolones * Beta-lactams

The Capnocytophaga spp. are **resistant** to what drugs?

Aminoglycosides

* Has 17 spp, but not all are related to man * (+) catalase, oxidase, glucose * (+) CHOC with grayish colonies * (-) MAC * (+) SBA (BAP) w/o satellitism, non-hemolytic, mucoid, narrow green to brown w/ halo around the colony * (+) bipolar staining in G/S with a safety pin appearance

Pasteurella spp.

What is the zoonosis of Pasteurella spp. and what are the involved organisms?

Systemic and cutaneous infections caused by **Pasteurella canis, Pasteurella stomatis, and Pasteurella dagmatis**

The most common isolate related to human infection involving the Pasteurella spp.

Pasteurella multocida

Familiarize yourself with the differential characteristics of Pasteurella spp.

Go mo na yan, it's in the transes!

T or F: Most of the Pasteurella spp. are zoonotic, but due to their proximity to dogs and cats, humans can get infected.

* The CDC categorizes them as **category B agents** since they can easily disseminate, cause moderate morbidity but low mortality * Under **BSL-3** requiring many precautionary measures * Facultative intracellular pathogens * **Colonies:** smooth, raised, translucent * (+) **Rose Bengal Test** and **2-mercaptoethanol (2-ME) agglutination Test**

Brucella spp.

What are the four members of the Brucella spp?

* Brucella melitensis * Brucella abortus * Brucella suis * Brucella canis

Best media for Brucella spp.?

* Castañeda broth * TSB (Trypticase Soy Broth)

Selective media for Brucella spp?

Wisconsin medium

This enhances the growth for Brucella spp.

Erythritol

What is the disease associated with the Brucella spp?

Brucellosis

# Identify the clinical stage of Brucellosis. Nonspecific symptoms (fever, malaise, headache, anorexia, myalgia, and back pain)

Acute

# Identify the clinical stage of Brucellosis. Undulating fevers (normal temp in the AM, high temp during PM), arthritis, and epididymoorchitis

Subchronic

# Identify the clinical stage of Brucellosis. Depression, arthritis, chronic fatigue syndrome

Chronic

Familiarize yourself with the differential characteristics of Brucella spp.

Nasa transes again hehe.

T or F: Natural hosts of Brucella spp. are usually humans.

F *(animals, hence they are **zoonotic**)*

* Categorized by the CDC as **Category A agents** * Can pose a risk to national security because they can be spread through person-to-person contact or are easily disseminated and result in high mortality rates, leading to a potentially great public health impact and public panic * BSL-3 * Fastidious, facultative intracellular * (-) oxidase, urease, satellite, X&V test * Weak (+) catalase and beta-lactamase activity

Francisella spp.

Francisella spp. requires the supplementation of what?

Cysteine, cystine, or thiosulfate

Familiarize yourself with the media used for Francisella spp.

* CHOC * Modified Thayer-Martin * Buffered Charcoal Yeast Extract (BCYE) agar * Mueller-Hinton agar * Trypticase Soy Broths (TSB)

Familiarize yourself with the serologic tests used as diagnostic tools for infections relating to Francisella spp.

* Direct fluorescent Ab (DFA) * Immunohistologic staining with monoclonal antibodies * PCR * Slide agglutination * Single serology test

This remains the gold standard as isolation allows visualization of the causative agent, giving an ideal method of diagnosis.

Culture

# Francisella spp. Most prevalent in human infection

Francisella tularensis

What are the three subspecies of Francisella tularensis?

* Tularensis (type A) * Holartica (type B) * Mediasiatica

* Also known as **rabbit fever, deerfly fever, lemming fever or water rat trapper’s disease** * **MOT:** ingestion, inhalation as pneumonia, arthropod ite in ulceroglandular form (by ticks, biting flies), or contact with infected tissue

Tularemia

Has 52 spp with >70 serogroups wherein **26** are isolated from humans

Legionella spp.

____ in Philadelphia in 1976 with 221 persons became ill with pneumonia-like symptoms wherein 34 of them died due to L. pneumophila.

American Legion Convention

* Agent of the outbreak * First named member of the family **Legionellaceae** * A primary human pathogen * 16 serogroups * **2 infections:** Legionnaires’ Disease, Pontiac Fever depending on the manifestation of the disease * Categorized based on **autofluorescence activity under UV light**: yellow-green, blue-white, blue-white/yellow-green, no color

Legionella pneumophila

# Legionella spp. * Manifests as **pneumonia** * **Top 4 causative agent** of community-acquired bacterial pneumonia * **Incubation:** 2-10 days * (+) hemoptysis (blood is expectorated with saliva), rales (crackles when coughing), dyspnea (difficulty in breathing), and shaking chills

Legionnaires' Disease

What are the two types of pneumonia caused by Legionella pneumophila?

Typical and Atypical

# Type of Pneumonia from Legionella pneumophila * Progressive disease wherein signs and symptoms appear fast from the contact with the organism * Crackles when coughing with mucoid phlegm

Typical

# Type of Pneumonia from Legionella pneumophila * Slower and lesser symptoms presented

Atypical

# Legionella spp. * Non-pneumonic; more flu-like symptoms of fever, headache, and myalgia that lasts for 2-5 days * Incubation: 2 days Subsides without medical intervention (self-limiting)

Pontiac Fever

T or F: Pontiac fever has more severe symptoms and manifestations and has a worse prognosis compared to Legionnaires’ Disease.

F *(other way around)*

Specimens for Legionnaires' Disease?

* Sputum * Bronchoalveolar lavage * Bronchial washings | From respiratory tract

T or F: Specimen that are stored in sterile and leak-proof containers are allowed in Legionella spp.

If there is a delay for less than 2 hours for specimen of Legionella spp, what should be done?

Refrigerate at 2 to 8 deg C

If there is a delay for several days for specimen of Legionella spp, what should be done?

Freeze at -70 deg C

Specimen used for antigen detection for serological testing

Urine

Result of microscopic examination for Legionella spp?

Weakly staining, gram-negative bacilli

Specimen for isolation for Legionella spp.?

Sputum

What should be done for sputum in isolation of Legionella spp?

Acid treatment with 1:10 with **0.2N KCl-HCl** stood for 5 minutes

# Isolation of Legionella spp. What is used to kill the normal microbiota?

0.2N KCl-HCl

Media used for isolation of Legionella spp?

CHOC with L-cysteine, BCYE

Best medium for isolating Legionella spp.

BCYE agar with L-cysteine

* Appear **grayish-white to bluish-green**, convex, and glistening (shining) * Central portion of young colonies appears light gray and granular w/ **ground glass appearance** * The **periphery** of the colony appears **pink or light blue or bottle green** with a furrowed appearance

Legionella spp.

What are the three conventional methods for Legionella spp?

* Gram-stain * L-cysteine * DFA Test

# Conventional Methods for Legionella spp. * For any suspicious colony growth on BCYE agar * Legionella spp. are thin G(-) bacilli * Spx from LRT

Gram-stain

# Conventional Methods for Legionella spp. * From suspected colonies * (+) SBA or BCYE with L-cysteine * (-) SBA or BCYE w/o L-Cysteine

L-cysteine

# Conventional Methods of Legionella spp. * A serological test * Prepare smears from colonies that require L-cysteine and lay over with polyvalent (Pseudomonas, Bacteroides, Corynebacterium) and monovalent conjugates to determine specific species and serogroup

DFA Test

What are the rapid methods for Legionella spp?

* Urine Antigen Test * DNA Detection * DFA Test

# Rapid Methods for Legionella spp. * Spx: urine * Methods: radioimmunoassay, microplate enzyme immunoassay, and rapid immunochromatographic assay * (+) infection with Legionella

Urine Antigen Test

# Rapid Methods for Legionella spp. * PCR for nucleic acid amplification * Well-refined MolBio procedures

DNA Detection

# Rapid Methods of Legionella spp. * Detection of more common species of Legionella * Conjugate + fluorescein isothiocyanate (fluorochrome) * Uses fluorescence microscope * (+) bright yellow to green, short or coccobacillary bacilli with intense peripheral staining

DFA Test

Drug of choice for **Legionella spp. in early dignosis?**

Azithromycin or fluoroquinolone

Alternative drug for Legionella spp. in early diagnosis?

Doxycycline

* There are 8 known spp and 2 are related to humans which are primary pathogens while the others are zoonotic * G(-) bacilli or coccobacilli * Fastidious, obligate aerobe * (+) catalase, oxidize, amino acid * (-) carbohydrate fermentation

Bordetella spp.

Growth of Bordetella spp. is inhibited by?

* FA * Metal ions * Sulfides and peroxides

Protective substances needed Bordetella spp. to counteract the inhibitors?

* Charcoal * Blood * Starch

# Species of Bordetella spp. Primary human pathogen | Two (2)

* B. pertussis * B. parapertussis

# Species of Bordetella spp. Respiratory tract pathogens of wild and domestic birds and mammals

* B. bronchiseptica * B. avium

# Species of Bordetella spp. Opportunistic human pathogen

B. bronchiseptica

# Species of Bordetella spp. Bacteremia among immunocompromised

B. holmesii

# Species of Bordetella spp. Ear infection in immunocompromised

B. trematum

# Species of Bordetella spp. Other species?

* B. hinzii * B. petrii

# Virulence Factors of Bordetella spp. * Facilitates attachment to ciliated epithelial cells

Filamentous Hemagglutinin (FHA)

# Virulence Factors of Bordetella spp. * Protein exotoxin that produces a wide variety of responses in vivo * **B. parapertussis and bronchiseptica** contain structural genes for PT but do not express the complete operon

Pertussis Toxin

# Virulence Factors of Bordetella spp. Modifies host proteins which interfere with signal transduction between cells and phagocytes

Adenosine diphosphate-ribosyl transferase

# Virulence Factors of Bordetella spp. * Inhibits **host epithelial and immune effector cells** by inducing supraphysiologic concentrations of **cyclic adenosine monophosphate** * Immune system is silenced

Adenylate Cyclase Toxin

# VIrulence Factors of Bordetella spp. * Causing ciliostasis, inhibiting DNA synthesis, and promoting cell death

Tracheal Cytotoxin

# Clinical Manifestations of Bordetella spp. * **1-3 weeks after incubation** * **Symptoms:** insidious, non-specific: sneezing, mild cough, runny nose, conjunctivitis * Highly communicate because of the large number of organisms in the respiratory tract * Cultures are not often performed

Catarrhal Phase

# Clinical Manifestations of Bordetella spp. * Severe, repetitive coughing with a “whoop” at the end of the coughing spell * Young children: pneumonia, or both and require aid in maintaining a patent airway * **B. parapertussis** presents a similar disease but with milder symptoms

Paroxysmal Phase

# Clinical Manifestations of Bordetella spp. There is a wheezing sound created during an attempt to grasp air in between coughs, which is a characteristic of Bordetella pertussis.

Whooping cough

# Clinical Manifestations of Bordetella spp. Target of pertussis?

Young children

# Clinical Manifestations of Bordetella spp. * After surviving the catarrhal and paroxysmal stages * 4 weeks after onset with decreased frequency and severity of coughing spells * Complete recovery can take weeks or months

Convalescent Phase

* Includes diphtheria, tetanus toxoid, acellular pertussis * Requires booster

DTaP vaccine

# Bordetella spp. * Kennel cough in dogs * Can cause parvo

B. brochiseptica

# Bordetella spp. Infrequently associated with pertussis syndrome and other RT infection

* B. bronchiseptica * B. holmesii

# Bordetella spp. Commonly associated with pertussis

* B. pertussis * B. parapertussis

Specimen of choice for Bordetella spp?

Nasopharyngeal swab or aspirate

# Specimen Collection and Handling for Bordetella spp. These are more preferred as they easily available and easy to prepare.

Swabs

# Specimen Collection and Handling for Bordetella spp. These have higher sensitivity when attempting to recover respiratory pathogens.

Flocked swabs

T or F: Throat cultures are less sensitive, hence discouraged.

# Transport System for Bordetella spp. Less than two hour delay?

1% casein hydrolysate (casamino acids) broth at RT

# Transport System for Bordetella spp. 24-hour delay?

Amies transport medium with charcoal at RT

# Transport System for Bordetella spp. Overnight or several day delay?

Regan-Lowe Transport Medium ## Footnote Containing half-strength charcoal agar containing 10% horse blood and 40 mg/L cephalexin at 350C

* Primary rapid diagnostic strategy * Circumvent many of the problems associated with specimen transport and bacterial cultivation * Uses at least two DNA targets (e.g., IS481 and pxtS1) * May need to seek confirmation to avoid the mischaracterization of respiratory illness

Nucleic Acid Detection

Microscopic examination for Bordetella spp?

DFA test + culture

# Microscopic Examination of Bordetella spp. * Uses **polyclonal fluorescent labeled conjugates** for both B. pertussis and B. parapertussis * DFA lacks sensitivity * False positive result

DFA test + culture

Bordetella spp. are incubated at what conditions?

35 deg C in ambient air for 7 days minimum

This is colony checking for Bordetella spp.

Stereomicroscope

Familiarize yourself with the media used for Bordetella spp.

* Bordet-Gengou potato infusion agar with glycerol and horse or sheep blood * Charcoal agar supplemented with 10% horse blood and 40 mg/L cephalexin * Regan and Lowe * Jones Kendrich: charcoal and yeast extract * Charcoal cephalexin blood agar (CCBA) * Stainer and Scholte broth * Casamino broth

# Young or old colony of Bordetella spp. * Smooth, glistening, and silver, resembling mercury droplets

Young colonies

# Young or old colony of Bordetella spp. * Turn whitish-grey

Older colonies

# ID Methods of Bordetella spp. * Tiny G(-) cocco bacilli *(elongated if from cephalexin-containing media)* * May need prolonged safranin exposure of up to 2 mins to see typical morphology

Gram-Stain

# ID Methods of Bordetella spp. * Exhibit bipolar granules of Bordetella

Toluidine Blue Bipolar Granules

# ID Methods of Bordetella spp. * For agglutination test or fluorescein-labeled antisera * Both (+) = no more confirmatory test = B. pertussis * Equivocal results = subculture to charcoal horse blood agar (CHBA), SBA, CHOC for biochemical testing

Suspicious Colonies

# ID Methods of Bordetella spp. * One of the most promising equipment * Mass spectrometry and 166 rRNA gene sequencing * For accurate ID

Matrix-Assisted Laser Desorption/Ionization Time Of Flight (MALDI-TOF)

* Assays cannot distinguish immune response between infection or vaccination * Whether it is a current or past infection * Cannot ID B. parapertussis vs B. pertussis infection * Foro detecting Ab and Ag

Serologic Testing

# Serologic Testing of Bordetella spp. * Enzyme immunoassay (EIA) or Bead-based assay * For diagnosis exposure to B. pertussis

Antipertussis Toxin AB

# Serologic Testing of Bordetella spp. * More ideal * **100 IU/mL:** recent infection * **>40 IU/mL:** looking for past infection or exposure * There is difficulty in diagnosis

IgG Antibody Titer

# Serologic Testing of Bordetella spp. * Not recommended, rarely done

IgM Antibody Titer

* **Sensitive** to macrolides, ketolides, penicillin, tetracycline * **Resistant** to oral cephalosporins

B. pertussis and B. parapertussis

# Antimicrobial Susceptibility of Bordetella spp. * DOC for treatment and prophylaxis * Efficient if treatment begins during the catarrhal phase * Some may exhibit resistance * Determine if it can still be used via AST

Erythromycin

# Antimicrobial Susceptibiity of Bordetella spp. * Longer half-life * High patient compliance due to fewer and milder side effects with fewer daily doses

Azithromycin

# Antimicrobial Susceptibility of Bordetella spp. * Alternative for treatment and prophylaxis in place of erythromycin

Trimethoprim-sulfamethoxazole

* Unpredictable susceptibility * Usually susceptible to aminoglycosides

B. bronchiseptica

(F) Lesson 12: Haemophilus and Other Fastidious Bacteria (Part 2) Flashcards

(145 cards)