Atypical Organisms. Mycoplasmas Characteristics –Lack cell walls –Pleomorphic (fried egg) –NM –FA-Obligate anaerobes Examples –M. genitalium –M. pneumoniae.

Atypical Organisms

Mycoplasmas

• Characteristics– Lack cell walls

– Pleomorphic (fried egg)

– NM

– FA-Obligate anaerobes

• Examples– M. genitalium

– M. pneumoniae

– M. hominis

• Diseases– Pneumonia

– Urogenital infections

Rickettsias

• GN (very little PG)• Intracellular parasites• Aerobic• Slow reproduction• Cell lysis for release• Arthropod vectors• Species

– R. rickettsii– R. typhi– R. prowazekii

RMSF• R. rickettsii• Dermacentor tick

– STD for ticks– Salivary gland host

blood

• Humans, rodents• Damage endothelium• CS

– F/N/V/myalgia– Spotted rash, pettechiae– Gangrene, paralysis– Encephalitis, death

• Dx : IFA, agglutination• Tx: AB, remove tick

Epidemic Typhus

• R. prowazekii• Pediculis louse• Human host• CC/CS

– Fever, depression– Rash

• Dx: IFA• Tx: AB• Pv: hygeine, sanitation

Murine (Endemic) Typhus

• R. typhi• Flea (rat, cat)• Rodent (murine) reservoir• Human exposure to fleas• CC/CS

– Fever, headache, myalgia– Rash on trunk and chest

• Dx: IFA• Tx: AB• Pv: Flea control

Scrub Typhus• Orientia tsutsugamushi• Red Mites (chiggers)• Rodents and Humans• Pacific

– Asia, Japan– Australia

• CS– Fever, headache – Myalgia, lymphadenopathy– Rash on trunk

• Tx: Ab• Pv: mite control, repellent

Ehrlichia and Anaplasma

• Emerging disease (1987)• Intracellular parasite in WBC• Hard Ticks

– Lone Star (Ambylomma)– Deer (Ixodes)– Dog (Dermacentor)

• Species– E. chaffeensis– E. equi (Anaplasma)

• CC/CS: – Fever, rash, leukopenia

• Dx: IFA• Tx: AB• Pv: Tick control

Chlaymdia• Intracellular parasite• No cell wall• 2 forms during

development– Elementary bodies (EB)

• Dormant, infective

– Reticulate bodies• Intracellular inclusions

• Species– C. trachomatis– C. pneumoniae– C. psittaci

Chlamydia trachomatis• Reportable STI• Human cells with EB receptors

– Respiratory– Female repro– Lower GI (rectum)

• CS– Ocular lesions (trachoma) scar

cornea blindnessor– Lymphogranuloma – Buboes – Genital sores – Urethritis, vagninitis, proctitis

• Dx: Giemsa stain, culture• Tx: AB• PV: safe sex

Chlamydia pneumoniae

• Community acquired• Droplet transmission• CS

– Sinusitis– Bronchitis– Chronic cough– Pneumonia– +/- atherosclerosis

• Dx: FA• Tx: AB

Chlamydia psittaci• Zoonotic• Parrot fever• Aerosolized EB in feces• CS

– Flu like symptoms– Pneumonia

• Dx: serology• Tx: AB• Pv: husbandry• Quarantine

Spirochetes

• GN, helical/coiled• Endoflagella• Corkscrew shape• Genera

– Treponema– Borrelia– Leptospira

Treponema• Human pathogen• Obligate intracellular

parasite• T. pallidum pallidum• Fastidious

– CH2O use– Host: FA, Protein, enzymes

• Double membrane– 2 flagella– Lack of surface proteins

• STI (STD)• Tx : AB [penicillins]• Syphilis

Syphilis• CS/Stages– 1 : Primary

• Active• Blister

– 2 : Disseminated• Latent• Rash

– 3 : Tertiary• CV (aneurysms)• NS (meninges)• Skin/Bone (Gummas)

– 4: Congenital • Fetus (stillborn) 3

1 2

Treponema pallidum …• T. p endemicum

– “Bejel”– MM– gummas

• T. p pertenue– “Yaws”– Skin: granular, draining

tracts• T. carateum

– “Pinta”– Skin papules flat

Hyper & depigmentation

Borrelia• Spirochete

– Endoflagella– Extracellular parasite

• Species and Strains– B. burgdorferi

• B. andersoniii• B. japonica• B. valaisiana

– B. lonestari

– B. turcica

– B. recurrentis

• Genetics– Linear chromosome– Plasmids

• Zoonotic• Arthropods

– Ticks– Fleas– Lice

• Dx: IF, serology, organism in blood

B. burgdorferi

• GN spirochete• Deer mice host, deer• Hard tick (Ixodes) spread (3x)• Lyme’s disease• CS

– Bull’s eye rash– Myalgia– Neuropathy– Arthralgia Chronic Arthritis

» MO IL-1, IL-6 TH 17 cells

• Dx: serology• Tx: AB• Pv: tick control, repellent

Relapsing Fever

• Borrelia recurrentis• Arthropod vector

– Lice (human)– Soft Tick

• Rodent reservoir• Humans• CS: fever, malaise• Dx: Blood smear• Tx: AB• Pv: vector control

Leptospira• Spirochete• Zoonotic• Species

– L. interrogans (humans)– L. ……..

• Transmission– Contam Urine water– Primary Hosts

• Rats• Mice• Moles

– Secondary Hosts• Dogs• Deer• Rabbits• Raccoons• Skunks• Opossums

Leptospirosis

• CS– N/V/F/headache– Pneumonia– Migrates through tissues

• Renal• Meningitis• Liver failure (Weil’s Ds)• Respiratory distress

• Dx: – Giemsa stain– titers

• Tx: – AB– fluids

• Pv: vaccinate animalsNA Epidemic ~1620 (Pilgrims)

Out breaks: Civil War, WWI, WWII

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