Additional Medically Relevant Bacteria Flashcards
Mycoplasmataceae
Lack a cell wall around their cell membrane
Believed they originated as Gram positive bacteria but evolutionarily lost cell wall
appear as gram negative (red) on gram staining
intracellular parasite
Ureaplasma produces urease
Mycoplasma pneumoniae
M. genitalium, M. hominis and Ureaplasma urealyticum
Chlamydia
Obligate coccoid to rod intracellular bacteria (parasites)
Gram negative
Infectious elementary bodies attach and are internalized by susceptible host cells
Intracellular reticulate (initial) bodies - replicative form
Steals host cell’s ATP via ATP/ADP translocator
C. pneumoniae, strain TWAR
C. trachomatis : trachoma conjunctivities; Nongonococcal urethrritis, cervicitis, salpingitis, endometritis, PID, inclusion conjunctivities (paratrachoma), lymphogranuloma venereum
C. psittaci: psittacosis, ornithosis.
Dx- identification of inclusion bodies
prevention: condoms
Rickettsia
Obligate intracellular pleomorphic gram negative coccobacilli
Steals host cell’s ATP via ATP/ADP translocator
Rickettsia akari (rickettsial pox from mice via mites with vesicular rash) Rickettsia prowazekii (epidemic typhus human to human via louse or in US via flying squirrels Rickettsia typhi (endemic/murine typhus Rickettsia rickettsii (Rocky Mountain spotted fever
dx- Weil-Felix test
test- nonspecific and insensitive based on
antigenic cross-reactivity between Rickettsia spp. and
certain serotypes of non-motile Proteus vulgaris
Orientia tsutsugamushi
Obligate intracellular parasite Not rickettsia (but in family rickettsiaceae)
transmitted by chigger (larval trombiculid mites)
Endemic regions- eastern asia and southwest Pactific
Scrub (bush) typhus– fever, headache, etc.
Coxiella burnetii
Not a Rickettsia
Obligate intracellular parasite
Requires host ATP
Worldwide zoonosis usually in cattle, sheep or goats and spread via inhalation of aerosolized organisms, unpasteurized milk products, ticks, pets or human to human
Dried organism excreted by host is easily aerosolized
Highly infectious (inhalation of one pathogen causes disease in 50%)
Has an endospore-like state
Causes Q fever
Ehrlichiosis &Anaplasmosis
Obligate intracellular parasite
Not a Rickettsia
Anaplasma phagocytophilum
–> human granulocytic anaplasmosis
Ehrlichia chaffeensis –> human monocytic ehrlichiosis
Ehrlichia ewingii (deer & dogs)
Dx- exam of blood for morulae
Bartonella
Gram negative pleomorphic bacilli
Oxidase negative
facultative parasite
NOT A RICKETTSIA
Bartonella henselae– cat-scratch disease, bacillary peliosis of liver and bacillary angiomatosis
Bartonella quintana–> trench fever
B. Bbacilliformis- in the Andes
Treponema
spirochete
weakly gram neg
Treponema cannot be grown in vitro
T. pallidum pallidum
Syphilis – see next slide
T. pallidum pertenue
Yaws (papule –> many papules on face and moist body areas –> gummas)
T. pallidum carateum
Pinta (papule —> many papules –> depigmentation or hyperpigmentation)
T pallidum endemicum Endemic syphilis (bejel) (oral ulcer --> oral, skin and skeletal lesions --> gummas with bone and nasal cartilage deformities)
Treponema pallidum
Syphilis
painless highly contagious hard chancre, generally found on the genitals (primary syphilis)–> rash on palms and soles (secondary syphilis)–> gumma and neurosyphilis (tertiary)
Congenital– half die in utero. Rest get symptoms after 2 yeras with Hutchinson triad (interstitial keratitis, notched incisors and sensorineural hearing loss)
Treponematosis - non-sexually transmitted form similar to yaws and pinta
Dx - of all of the subtypes of T. pallidum- clinical presentation, anti-cardiolipin serology [rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) tests], direct treponemal antibody tests [fluorescent treponemal antibody absorption (FTA-ABS), T. pallidum particle agglutination assay (TPPA) tests] and darkfield or fluorescent antibody examination of material from lesion
Wasserman test was originally used.
Rx- penicillin G
Prevention- condoms
Borrelia
B. Burgdorferi & B. mayonii (possibly other species)
Lyme disease spread from rodents via hard-shelled deer ticks (Ixodes scapularis)
and develop erythema migrans
B. recurrentis
Louse-borne (epidemic) relapsing fever
B. hermsii
Tick-borne (endemic) relapsing fever
Leptospira
pathogenic Leptospira interrogans
Leptospirosis
Worldwide zoonosis; rats, mice and moles
leptospiremic phase: broken skin provide entry
leptospiruric phase: localize in the kidneys and shed in the urine
Anicteric leptospirosis- headache, fevers, muscle pain, etc. (anicteric= not turning yellow)
Weil disease (icteric eptospirosis) - dysfunction of kidneys and liver
Mycobactericea
Part of the CMN group (corynebacteria, mycobacteria and nocardia)
Contain polymer complex composed of peptidoglycan, arabinogalactan and mycolic acids
Rod-like to filamentous
Mycobacteria and nocardia are acid fast
Use Ziehl-Neelsen stain for identification
Cord factors - dimycolates of trehalose give rise to growth in serpentine cords
Cord factors inactivate mitochondrial membranes of phagocytes allowing organisms to survive and multiply in phagocytes
M. tuberculosis complex: M. tuberculosis, M. bovis
M. tuberculosis – tuberculosis (Spread by airborne droplets and can cause prolonged productive cough)
M. bovis – oropharyngeal and intestinal tuberculosis via unpasteurized cow milk
M. leprae - tuberculoid or lepromatous leprosy (Hansen disease)
Nontuberculous mycobacteria:
Tuberculosis
Primary infection: ghon complex, granulomatous response
secondary infection: reactivation of old welled-off lesions
Miliar TB- tubercle erodes into a vessel
non-pulmonary may –> cervical lymphadenitis (scrofula)
In immunoseuppressed may see TB without granulomas
Prevention: bacillus Calmette-Guerin (BCG) vaccine
Hansen disease
= leprosy
m leprae replicates in cooler temps of skin
tuberculoid form- 5 or fewer skin lesions with absence of organims on smears
Lepromatous- multivacillary form: 6 or more lesions with possible visualization of bacilli on smear
Dx – M. leprae has never been cultured in vitro but can be grown on the footpads of armadillos, positive lepromin (injected M. leprae antigens) only in tuberculoid form
Non-Tuberculous Mycobacteria
Mycobacterium avium complex [M. avium, etc.) and others (M. intracellulare)
Can cause pulmonary disease resembling tuberculosis, lymphadenitis, skin disease, soft tissue disease or disseminated disease
Usually identified in immunocompromised patients
