unusual GNRs

bordetella parapertussis

bordetella parapertussis

• less severe whooping cough in children with a shorter duration

• brownish discoloration on media

b. bronchiseptica

• opportunistic pathogen for pneumonia and wound infections

• kennel cough in dogs (vaccine required)

• milder symptoms, grows on MAC

b. pertussis/parapertussis transmission

• aerosols (bacteria adhere/grow on ciliated resp epi cells

• highly contagious: 90% exposed contract disease; adults can be transient carriers

b. pertussis/parapertussis virulence factors

• FHA: attach to epi cells

• pertussis toxin (PT): inc cAMP = inc resp secretions/mucus

• adenylate cyclase toxin: inc cAMP, inhibits chemotaxis, phagocytosis

• tracheal cytotoxin: ciliostasis (cilia cannot clear airway)

whooping cough

• 1-2wks incubation period

• catarrhal: flu like, sneezing, runny nose 1-2 wks; highly contagious

• paroxysmal: sudden, severe cough followed by whoop

  • inc lymphs (looks like viral or leukemia)

• in kids: cyanosis, very serious, need help breathing

• convalescent: 4 wks after symptoms; dec coughing but can be wks-mos before recovery

what specimen is needed for whooping cough dx?

• nasopharyngeal: aspirate of fluid

  • calcium alginate or dacron swabs as deep as possible

    • cotton oils toxic to bordetella

how to culture bordetella?

• bordet gengou: potato infusion + glycerol + sheep blood

• regan lowe agar: charcoal with 10% horse blood, cephalexin

• also BAP, MAC, CHOC (r/o haemophilus)

• incubate 35C, no CO2, 7 days, adequate moisture with gauze

morphology of b. pertussis

• GN rods/ccb

• bordet gengou: small, domes, glistening (bisected pearls) often beta

• regan lowe: smooth, silver, pinpoint (mercury droplets)

DFAs

• b. pertussis: used for confirmation; requires larger amt of organism for agglutiantion test

• francisella: safer

• legionella: can cross react with p. aeruginosa

how to treat b. pertussis

• 1 month: erthryomycin, clarithromycin, azithromycin

• <1 month: azithromycin (erythro assoc with infantile hypertrophic pyloric stenosis)

• STX alternative for > 2months

brucellosis (undulant fever)

• reoccurring fever at regular intervals for days/mos/yrs

• fever at night that goes away during day

• wt loss

• acquired from livestock contact (unpasteurized milk)

transmission of brucella

• undercooked meat, unpasteurized/raw milk

• breathing in bacteria (dust, droplets) (lab workers)

• thru skin wounds/abrasions/mucous membranes

  • slaughterhouse, meat packing, veterinarians

b. melitensis

• goats/sheep

• most common isolate

• severe disease, acute suppurative, granulomatous lesions

• thionin and fuchsin

b. abortus

• cattle

• mild sporadic disease, chronic granulomas in RE system organs

• causes infectious abortions in cattle (bang’s disease)

• fuchsin, H2S, capno

b. canis

• dogs

• similar disease to b. abortus

• thionin

b. suis

• pigs

• destructive suppurative lesions; prolonged disease with granulomas mimicking TB

• H2S, thionin

specimens for brucella isolation

• RES predilection = bone/BM

• sterile BFs and urine also possible

brucella characteristics

• strict aerobes (some capno)

• slow grower (21 days); brucella blood agar

• non spore forming, w GN ccb (extend safranin stain time)

• non motile, no capsule, intracellular

• agent of bioterrorism = work in BSC

brucella biochemicals

• ox pos, cat pos

• H2S and urease help speciate

• submit acute/convalescent sera for sero testing

where is francisella found?

• wild animals: rabbits, muskrats, beavers

  • outbreaks lead to lots of deaths of these animals

• ground water

francisella transmission

• zoonotic: tick/deer fly = primary vector

  • skin contact, ingestion/inhalation of contam water, dust, aerosols

  • hunters: handling carcasses, bitten, aerosols

  • mowing lawn

• lab workers at risk

rabbit fever = francisella

• acute febrile, granulomatous disease with rapid onset and flu like symptoms

• 5 presentations depending on site of infection:

  • ulceroglandular

  • glandular

  • oculoglandular

  • oropharyngeal

  • pneumonic

francisella growth characteristics

• facultative intracellular

• non motile, small GN ccb

• strict aerobe

lab dx - francisella

• culture not recommended

  • Lcystine, animal serum, egg yolk

  • cystine BAP

  • slow grow CHOC, no MAC growth

  • cystine heart dextrose = clear, pearlescent, convex, drop like colonies

    • sub to BCYE to keep alive

• DFA, IHC, PCR, serology

pasteurella srouce

URT and GI tract of mammals/birds (dog/cat scratches/bites OR inhaled)

pasteurella diseases

• local: cellulitis, abscesses, osteomyelitis, septic arthritis

• resp: URTIs, pneumonia, tracheobronchitis, lung abscesses

• cardiovascular: endocarditis, bacteremia, sepsis

• CNS: rare meningitis (licks/bites to face in old ppl)

• GI, ocular, UTIs

p. multocida growth characteristics

• GN pleomorphic ccb with bipolar staining (oval, short rods, longer filaments)

• BAP, CHOC, no MAC

  • small gamma, mucoid, narrow green/brown halo

  • musty, mushroom, dog’s breath odor

p. multocida biochemicals

• ox pos, cat pos

• nonmotile

• weak acid from glucose ferm

• pos indole, ODC

• lack of rxns leads to misID on automated systems

klebsiella granulomatis

• endemic in tropical/developing countries (rare US)

• causes donovanosis: uncircumcised men with poor hygiene, spread via sexual contact, can spread to bone/liver, assoc w pregnancy/cervical infection

donovanosis

• firm papule or subcut nodule that ulcerates at primary site of inoculation (genital area); swells lymphs nodes with lesions on skin above)

• ulcerogranulomatous: hard, red, bleeds easily

• hypertrophic or verrucous ulcer: dry, irregular edge

• deep ulcer: necrotic, foul smelling

• dry, sclerotic, cicatricial lesion: scarring

donovanosis dx

• no cultures

• based on pt hx and disease presentation

  • confirmed with donovan bodies (intracellular) on tissue smears in macros, occ encapsulated

• PCR not FDA approved

• IFA thru ref labs

capnocytophaga

• normal oropharyngeal flora (some in humans, some in dogs/cats)

• not speciated in lab

capnocytophaga diseases

• more septicemia than endocarditis (pts with neutropenia)

• juvenile periodontal disease

• fulminant, life threatening disease following dog/cat bite

growth characteristics of capnocytophaga

• GN rod fusiform (resembles fusobacterium (anaerobe))

• facultatively anaerobic

• CO2, BAP, CHOC after 2 days, no MAC growth

• TM or ML agar (resistant to antimicrobials in these plates)

• gliding motility on agar (like swarming)

capnocytophaga biochemicals

• negative for most

• motile

• pos nitrate, esculin

• ferm: glu, mal, lac, suc

legionella spp

• intracellular parasite: enter and multiply within host cells (bronchoalveolar macros)

• predisposed in:

  • immuno comp, chronic lung disease, alcoholics, heavy smokers

how to contract legionnaires’ disease

• inhalation of aerosols (not person to person)

• sporadic - community acquired

• epidemic: AC, cooling towers, fountains, windshield washers

• nosocomial in IC: resp equipment, nebulizers, humidifiers, spas, ice machines

legionnaires’ disease

• range from asymptomatic to deadly

• 2-10 day incubation

• nonproductive cough, fever, headache, myalgia, bloody/purulent sputum, rales, difficultly breathing, shaking chills

• dissemination to kidneys, heart, liver, CNS, lymphatics

  • damage to organs = death

• mortality 15-30% sometimes 50%

• most are serogroup 1

pontiac fever

• 2 day incubation

• flu like symptoms: fever, headache, myalgia 2-5 days

• spontaneous recovery, milder form, low mortality

reservoirs of legionella

• lakes, rivers, springs, man made water treatment systems (chlorinated water okay)

• heating/cooling towers of buildings; fountains

• can live at 20-43C up to 60C

• adheres to pipes, rubber, plastics

• intracellularly in protozoa

specimen collection for legionella

• resp: BAL, sputum, bronchial washings

• urine for Ag test

  • found in urine for serogroup 1; stays pos for long time

legionella lab ID

• direct examination: pleomorphic thin w GNRs inside macros/neutros and extracellularly

• urine Ag test

• DFA test

• check serotypes or DNA detection

how to culture legionella

• aerobically, requires L cysteine (no primary media)

• BCYE: small pinpoint colonies

  • acid wash to remove normal flora

• biplate: cystine/without cysteine (growth only on one side)

• 35-37C 7 days; gray white or blue green convex, wet looking, will fluoresce

how to treat legionella

• erythromycin (alone or with rifampin)

• alt: doxy, STX, new macrolides, fluoroquinolones

streptobacillus moniliformis diseases

• rat bite fever: bite/scratch from infected animal

• haverhill fever: ingestion of contam material

• abrupt onset fever, chills, headache, myalgia

• maculopapular, petechial, pustular rash in extremities

• joint swelling/pain

• can progress to endocarditis, myocarditis, meningitis, pneumonia, sepsis

s. moniliformis lab ID

• specimen: primary lesion, lymph node, blood, joint fluid, pus

• pleomorphic GNR; bulbous string of pearls/L shapes with age

• enrich media with whole blood, serum, ascitic fluid

  • SPS in blood cx inhibits

  • gray, smooth, glistening, fried egg with L phase

spirillum minus

• rat bite fever (sodoku)

• fever, ulcer, swelling, lymphadenopathy, rash on palms/soles, headache, vomiting

• GN spiral rods with 2-3 coils, motile, stain with wright giemsa

• cannot be cultures (dx on symptoms/microscopy)

b. henselae

• cat flea = cat scratch disease

• fever, lymphadenopathy, papule/pustule at infection site

• eye infections, severe muscle pain, encephalitis

b. quintana

• body louse = trench fever

• fever (recurrent), headache, rash, bone pain in shins/neck/back

b. bacilliformis

• sand fly = carrions disease in western south america

• oroya fever: fever, headache, myalgia, abd pain, severe anemia

• verruga peruana: peruvian warts; nodular lesions under skin that emerge, ulcerate, bleed

complications with bartonella

• bacillary angiomatosis (BA): henselae, quintana

• bacillary peliosis: henselae

  • lesions in skin, subcut tissue, bone, liver, spleen

  • HIV/IC

• SBE: does not show up in culture

growth characteristics of bartonella

• cx from skin, lesion biopsy, occ blood

• standard media but takes weeks to grow

dx of bartonella

• CSD: symptoms, hx, sero, PCR

• trench fever: blood cx, sero

• carrions: blood cx, blood smears in acute phase (oroya)

• endocarditis: sero, PCR, cx heart tissue