unusual GNRs

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
*

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