Bacteria Ii Answers – Flashcards
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| Bordetella |
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| only human reservoir; person-to-person transmission via respiratory droplets; short-time survival outside of body; most common in 1-5 year olds of non-immunized population |
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| N. gonorrheae |
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| only in humans Asymptomatic carriage is major reservoir – susceptible to drying out transmission by sexual contact; rare through infected vaginal canal lack of protective immunity – antigenic variation |
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| NM |
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| only in humans-nasopharyngeal flora Transmission by aerosolization Outbreaks in winter and early spring endemic in children younger than 5as passibe maternal antibodies declines During epidemics: immunocompromised, elderly, closed populations |
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| Escherichia general |
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| normal flora |
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| ETEC |
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| • developing countries • transmission through focally contaminated food |
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| EPEC |
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| • developing countries • person-to-person spread • rare outbreaks in daycare centers |
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| EAEC |
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| • infant diarrhea in developing countries and travelers • some outbreaks in US, Europe, and Japan |
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| EHEC |
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| • most common strains in developing countries (O157:H7) • Transmission to humans from animals via undercooked meat, unpasteurized milk or juice, water, uncooked veggies and fruits o cook ground beef at 160 F o pasteurize milk/juice |
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| EIEC |
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| • Children <5 y/o in developing countries |
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| Salmonella |
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| widely distributed in nature – animal and human reservoirs Transmission: ingestion of contaminated food or fecal-oral route Highest risk: <5 yo and>60 y/o summer and autumn poultry, eggs, dairy products and contaminated uncooked foods (veggies and fruits) |
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| Shigella |
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| humans only reservoir person-to-person via fecal-oral route usually contaminated hands • sometimes water or food • occasionally flies with open sewage Primarily children under 10 y/0: • adults in household, day care centers and institutions |
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| Yersinia |
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| Associated with animals • Y. pestis: urban plague = rats; sylvatic plague = squirrels, rabbits, rats, cats o flea vector or contact with contaminated animals or animal tissues • Y. enterocolitica = pigs, rodents, livestock, and rabbits o contaminated milk, meat, or water • Y. pseudotuberculosis = rodents, wild animals, game birds o not as common |
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| Vibrio |
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| estuarine and marine environments worldwide • survival and replication in contaminated waters with increased salinity and at temperatures of 10-30 C Asymptomatic humans serve as important reservoirs in endemic areas |
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| Aeromonas |
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| ubiquitous in fresh and brackish water |
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| Camphylobacter |
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| ubiquitous reservoirs: mammals and fowl, both wild and domestic transmission: contaminated food (esp. poultry), milk and water |
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| Helicobacter |
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| common worldwide person-to-person by fecal-oral route colonization may be life-long |
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| Psuedomonas |
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| o ubiquitous o opportunists o P. aeruginosa is major nocosomial infection o growth in laboratory water baths, hot tubs, wet IV tubing, other waste-containing vessels |
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| Haemophilus |
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| o unencapsulated: component of normal flora o capsulated: not usually part of normal flora o H. influenza type b was major pathogen prior to intro of vaccine: caused meningitis, pneumonia, epiglottis—now rare in US |
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| F. tularensis |
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| zoonotic transmission: infective deerfly or tick, directly from blood of infected animal, eating undercooked meat, laboratory contraction, inhalation summer (ticks) or winter (hunters) potential biological weapon |
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| B. melitensis |
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| worldwide domesticated and wild animals: through the skin, contaminated meat or dairy products, laboratory workers, inhalation rarely through respiratory tract or conjunctiva potential biological weapon |
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| legionella |
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| o worldwide o normal habitat is water (live in amoebae): lakes and streams, air conditioning cooling towers and water distribution systems (showers and hot tubs), chlorine and heat tolerant o transmission via inhalation of aerosolized organisms o nosocomial o American Legion at convention in Philly: see slide for details o Risk factors: Alcoholism, advanced age, smoking, immunosuppressive therapy, renal transplant and cancer patients |
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| Bartonella general |
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| Human reservoir |
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| B. bacilliformis |
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| Sandfly vector; South America at intermediate altitudes |
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| B. henselae |
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| Cat and flea vectors |
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| Clostridium |
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| part of intestinal flora in humans and other animals soil, sewage, and aquatic settings able to survive adverse environmental conditions non-invasive, but produce destructive infections when introduced to traumatized tissues |
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| Actinomyces |
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| o normal flora of mucus membrane of humans and animals: oral cavity, GI tract, female genital tract o Opportunistic o no person-to-person spread or external source |
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| Spirochetes general |
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| free-living to normal flora |
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| T. pallidum |
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| strict human pathogen (causes syphilis) transmitted via sexual body contact (primary) or transplacentally (congenital) • mode of entry: break in skin or penetration of mucous membranes |
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| B. burgdorferi |
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| Lyme Disease • most common arthropod-transmitted disease in US • transmission via bite of small hard shelled tick (saliva) o primary reservoir: mice and deer • Occurrence: seasonal and parallels increased outdoor activity (summer months) |
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| B. recurrentis |
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| person-to-person via human body lice (no other host) condition of poor hygiene: crowded, unsanitary, louse-infested environments |
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| L. interrogans |
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| animal disease (rodents and small mammals, dogs and farm animals are incidental hosts) • via water contaminated with animal urine • occupational exposure to animals • via small skin abrasions of conjunctiva ubiquitous |
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| Mycoplasma pneumoniae |
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| agent for tracheobronchitis and primary atypical pneumonia (~10% of all cases of pneumonia); transmission: person-to-person via respiratory droplets; worldwide distribution, year-round; highest incidence in oder children, young adults (6-20 y/o) |
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| M. hominis, M. genitalium, and U. urealyticum |
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| Infants (females) are colonized w/ agents at birth; only small number of prepubertal; genital mycoplasmas assoc. with sexual activity |
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| Rickettsia |
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| Vectors: fleas, ticks,mites, or lice; Reservoirs: rodents, humans (accidental), or arthropods |
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| Rickettsia rickettsii |
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| Most common rickettsial infection in US; Most common from April-September; Vector: hard tick via saliva (prolonged exposure needed); Reservoirs: ticks (transovarian passage), rodents, humans (accidental) |
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| Rickettsia akari |
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| sporadic infection in US; Vector: mite; Reservoir: mites (tranovarian) and mice |
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| Rickettsia prowazekii |
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| unsanitary conditions; vector: human body louse (feces, no transovarian transmission); reservoir: humans (epidemic form); sporadic disease in SE US (reservoir-flying squirrel, vector-squirrel fleas, humans accident) |
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| Rickettsia typhi |
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| ubiquitous in warm, humid areas(Gulf States, Cali); Vector: rat flea (feces);Reservoir: rats (humans accidentally infected) |
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| Ehrlichia |
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| Vector: Lone star tick; Reservoir: White-tailed deer; Distribution: SE, Mid-Atlantic and South Central US |
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| Anaplasma |
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| Vector: Deer and dog ticks; Reservoir: small mammals; Dist: Wisconsin, Minnesota, and Connecticut |
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| C. trachomatis, Biovar: trachoma |
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| Worldwide (poverty, overcrowding); infection in children; transmission: droplets, hands, contaminated clothing, flies, contaminated birth canal; leading cause of preventable blindness |
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| C. trachomatis, biovar: trachoma, GTI |
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| most common bacterial STD in US |
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| C. trachomatis, biovar: LGV |
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| prevalent in Africa, Asia, and South America; sporadic in US |
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| Chlamydophila psittaci |
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| 25-200 cases/year in US; primarily an occupational disease (vets, poultry workers, zoo keepers, pet shop workers) |
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| Chlamydophila pneumoniae |
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| many infections are asymptomatic; person-to-person transmission via respiratory droplets; significant cause of community-acquired respiratory infections (ubiquitous); assoc. w/ crowded conditions: schools, military bases; possibly responsible for adult-onset asthma |
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| Coxiella burnetti |
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| stable in harsh environments; infects sheep, goats, cattle, and cats; high titers in placentas of infected animals; milk of infected animals; ticks are primary vector (inhalation of airborne particles) |
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| B. quintana |
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| body louse |
