Needy GNB, GNDC, Spirochetes, Obligate Intracellular Organisms, and Organisms without a Cell Walll

chracteristics of HACEK group

capnophilic

normal flora of oropharynx

rare cause of endocarditis and bacteremia after dental procedures

slow growing GNB and GNCB

What factors does Haemophilus influenzae require?

FX and FV

The BAP of a culture showed tiny clear colonies growing only around beta-hemolytic colonies of Staphylococcus aureus. The CHOC agar showed yellow colonies of S. aureus and medium sized grey colonies. What is the best explaination for why the growth on BAP and CHOC is so different?

Haemophilus influenzae is present and is satelliting around the S. aureus

Which media whould you see Haemophilus influenzae grow on?

CHOC agar

Haemophilus influenzae causes

pneumonia, meningitis and ear, eye, and sinus infections

What organism causes chancroid and displays characteristic chaining gram-negative bacilli that may be described as "schools of fish"?

Haemophilus ducreyi

A human bite wound grows a colony that "pits" the agar and smells like bleach. The colony gram stain showed gram-negative bacilli. What is the most likely identification?

Eikenella corrodens

Organisms associated with animal bites

Capnocytophaga

Pasturella

Francisella

Haemophilus aegyptius is associated with

conjunctivitis

A patient reported to the ER with symptoms of an intermittent fever lasting weeks and fatigue and muscles aches. The patient reported frequent consumption of unpasteurized milk. Blood cultures were drawn and were positive after 7 days. Tiny gram-negative coccobacilli were observed in the blood smear. What is the most likely identification?

Brucella

Which organism does NOT require any special precautions when manipulating culture plates?

Pasturella multocida

Francisella tularensis is a zoonosis human acquire from contact with what type of animal?

rabbits and squirrels

What would be the optimal media choice for isolating Francisella tularensis?

blood cysteine glucose agar with thiamine

How is Legionella pneumophila transmitted?

inhalation of contaminated aerosolized water from water systems

What test is most commonly performed to diagnose Legionnaire's Disease?

a urine antigen test

If needing to set up a culture for Legionella pneumophila what special media would need to be used?

BCYE

Bordetella pertussis causes

whooping cough

What type of specimen should be collected for the diagnosis of Bordetella pertussis?

an NP swab

What special media would be appropriate to inoculate for culture of Bordetella pertussis?

Regan-Lowe

Besides culture, what other testing method is commonly used to diagnose Bordetella pertussis?

molecular

Treponema pallidum subsp. pallidum is the causative agent of

syphilis

Which tests are nontreponemal (lipoidal antigen) tests?

RPR and VDRL

Which category of syphilis test should be used to monitor therapy?

nontrponemal

The RPR uses cardiolipin-lecithin antigen to detect ________

reagin antibodies

Borrelia burgdorferi causes

lyme disease

How do humans acquire Leptospira interrogans?

through exposure to soil/water contaminated with animal urine

Neisseria is catalase ___________ and oxidase ___________

positive, positive

Moraxella is catalase ___________ and oxidase ____________

positive, positive

The CTA sugars for Neisseria meningitidis are positive for

glucose and maltose

Disseminated Neisseria gonorrhoeae notably causes what type of infection?

joint infections

Though we may isolate Neisseria gonorrhoeae on culture, what method do we commonly use to test for the STI

molecular

is a vaccine for Neisseria meningitidis available

yes and is recommended

Moraxella catarrhalis is butyrate esterase ___________

positive

A patient reported having a "cold" 3 weeks ago and now presents with sinus pressure, headache, and teeth pain. A diagnosis of sinusitis is made, a sinus aspirate collected, and culture set up. The gram stain showed many WBC and gram-negative diplococci. The culture grew a medium white colony grew on both the BAP and CHOC, and the MLS noted the colonies scooted across the agar like a hockey puck. What organism is causing the sinusitis?

moraxella catarrhalis

Mycoplasma hominis has been noted to cause

urethritis

What makes Mycoplasma unique

they do not possess a cell wall

What media does Mycoplasma need to grow

biphasic liquid media

Walking pneumoniae is caused by what organism

mycoplasma pneumoniae

Rickettsia rickettsia is acquired by

tick vectors

Rickettsia rickettsia causes

rocky mountain spotted fever

Erythromycin eyedrops are given to neonates to prevent ophthalmia neonatorum (neonatal conjunctivitis). What organism most commonly causes this infection?

chlamydia trachomatis

What is the most common method we use to diagnose the STI Chlamydia?

molecular

HACEK stands for

Haemophilus

aggregatibacter

Cardiobacterium and Capnocytophaga

Eikenella

Kingella

GNCB

growth on CHOC not BAP

requires FV and FX

serotype B (most severe but vaccine has decreases cases)

Haemophilus influenzae

most common Haemophilus in the US

nontypeable H. influenzae acquired by person to person or endogenous route

causes epiglottitis, otis media, conjunctivitis, pneumonia, bacteremia, and meningitis

Haemophilus influenzae

main Haemophilus pathogens

H. influenzae and H. ducreyi

how is Haemophilus speciated

based on growth requirements

X factor

hemin (released upon hemoglobin breakdown)

V factor

NAD (compound produced by some bacteria and yeast)

causes an STD, chancroid

requires X factor

very fastidious (isolate on CHOC)

“chaining school of fish”

Haemophilus ducreyi

causes conjunctivitis

associated with brazilian purpuric fever

Haemophilus aegyptius

grows on BAP nd CHOC

associated with dental plaque and periodontitis

Aggregatibacter

grows on BAP and CHOC

GNR with tapered ends on gram stain

Cardiobacterium

grows on BAP and CHOC

bleachy odor

pits the agar

Eikenella corrodens

infection is caused by human bite wounds

can cause septicemia after dental extractions

prefers CHOC agar but will grow on blood

Eikenella corrodens

grows on BAP and CHOC

beta-hemolyitic

causes joint infections

Kingella

short GNCB

some pit the agar

can grow on Theyer Martin

catalase negative and oxidase positive

Kingella

thin tapered GNB

sprrady pinkish-yellow on BAP

normal oral flora of humans or cats/dogs

Capnocytophaga

causes infections from dog or cat bites and scratch wounds

Capnocytophaga

grows on BAP and CHOC

normal flora to cats, dogs, and other animals

musty ordor

infection caused by animal bite/scratch wound

Pasturella

this species of pasturella is most the most common GNB

Pasturella multocida

faint staining GNB

grows best on blood cysteine glucose agar with thiamine (can grow on BAP and CHOC in 2-4 days)

category A bioterrorism agent

Francisella tularensis

causes zoonosis (aquired through contact with rodents or tick/deer flies, sometimes by biting flies)

symptoms depend on means of transmission but generally involve an ulcer

Francisella tularensis

causes tularemia

S/S: fever, chilss, and lymphoadenopathy

Francisella tularensis

can cause lab acquired infections

capsule allows resistance to phagocytosis

catalase positive and oxidiase negative

Francisella tularensis

aerobic faint staining GNB

will grow on BAP and CHOC but needs extended incubation

you’ll isolate on blood cultures but diagnose with serology

Brucella

zoonosis causes Brucellosis or undulant fever (livestock and wild game are reservoirs)

acquired through ingesting contaminated food or inhalation

Brucella

category B bioterrorism agents

infection causes undulant fever aka malta fever (wave-like fever, rises and falls)

Brucella

acquired through ingestion of contaminated diary, inhalation of aerosilized particles or abrasion from handling infected animal

requires level 3 safety hood and extended incubation of 3 weeks

Brucella

faint staining gnb

found in freshwater and plumbing

no growth on BAP

Legionella pneumophilia

acquired by inhalation from water systems (ex: air conditioners or plumbing systems)

requires a buffered charcoal yeast extract agar (BCYE)

diagnose with a urine antigen test

Legionella pneumophilia

no person to person transmission

organisms appears to have preference for older males who smoke

infection causes legionnaire’s disease (pneumonia) and pontiac fever

Legionella pneumophilia

small gnb

acquire through respiratory (droplets person to person)

can be prevented with a vaccine (DTaP/Tdap)

Bordetella pertussis

has strong affinity for cilated epithelial cells in the mucous membranes of the respiratory tract

a nonpathogenic specimen is used for culture and molecular testing

requires Bordet-Gengou or Regan-lowe for isolation

Bordetella pertussis

very contaigous

virulence factors include a capsule, endotoxin, and pertussis toxin

causes whooping cough

Bordetella pertussis

needs 7 to 20 day incubation

optimal specimen for culture is from the oropharynx

PCR is the best way to detect it

Bordetella pertussis

GNDC that are normal flora to the upper respiratory tract and genital tract of humans

saprophytic Neisseria

intracellular GNDC

oxidase and catalase positive

not normal flora

Neisseria gonorrhoeae

CTA glucose positive

grows well on CHOC may grow on some BAP

requires Thayer Martin to isolate

Neisseria gonorrhoeae

diagnose via molecular (most common)

infections include STD’s, gonorrhoeae, neonatal conjunctivitis, and arthritis

Neisseria gonorrhoeae

organisms is aerobic and capnophilic (dies in refridgeration)

must use a dacron swab to culture

transport media can’t dry out the organism

Neisseria gonorrhoeae

GNDC

CTA glucose and maltose positive

vaccine is available (meningococcal)

Neisseria maningitidis

spread through respiratory droplets of infected/colonized people (close contact)

shiny/mucoid growth on BAP and CHOC

will grow on Thayer Martin

Neisseria meningitides

aerobic and capnophilic

infection causes meningitis and bacteremia

Neisseria maningitidis

GNDC

normal flora of upper respiratory tract

catalase and oxidase positive

Moraxella catarrhalis

aerobic and capnophilic

butyrate esterase positive

“hockey puck” morphology on BAP and CHOC

Moraxella catarrhalis

infection causes secondary infection (endogenous), pneumonia, otitis media, and sinusitis

Moraxella catarrhalis

no cell wall

must use liquid biphasic media to grow

diagnose by molecular (respiratory panel)

Mycoplasma pneumoniae

causes walking pneumonia

Mycoplasma pneumoniae

organisms without a cell wall that can cause urethritis, bacterial vaginosis, and associated with infertility

diagnose via molecular

Mycoplasma hominis, genitalum, and urealyticum

obligate intraceullar bacteria

diagnose via molecular

infection causes neonatal conjunctivitis, pneumonia, and chlamydia

Chlamydia trachomatis

obligate intracellular bacteria

transmitted by tick vector

diagnose by indirect fluorescent antibody testing (serology)

Rickettsia

infection causes rocky mountain spotted fever (fever, headache, fatigue, and a splotchy rash)

Rickettsia

obligate intracellular bacteria

transmitted by tick vector

diagnose by molecular

infection causes Erlichiosis (fever, chills, headache, and possibly a rash)

Ehrlichia

obligate intracellular bacteria

transmitted by tick vector

diagnose via molecular

infection causes anaplasmosis (fever, chills, headache, and muscle aches)

Anaplasma phagocytophilum

spirochete

diagnose with darkfield microscopy if they have sores with viable organism

diagnose with serology (combination of nontropenemal/lipoidal (RPR) and treponemal (TTPA)

Treponema pallidum subsp. pallidum

infection causes syphilis:

primary - chancre

secondary - rash

tertiary- multiple organ damage

Treponema pallidum subsp. pallidum

spirochete

transmitted by ticks

causes lyme disease or relapsing fever

Borrelia

causes a “bull’s eye” rash

culture takes up to 12 weeks (dependent on stage of disease) therefore testing is usually done by ELISA for antibodies

confirmation by western blot must be preformed for all positive by ELISA

Borrelia burgdorferi