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35 Cards in this Set
- Front
- Back
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what toxins does Pseudomas produce? How does it attack tissues and cells?
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Factors that contributes to the pathogenicity include production of exotoxin A, which kills host cells by inhibiting protein synthesis, and production of several proteolytic enzymes and hemolysins that destory cells and tissue. On the bacterial surface pili may mediate attachment to host cells. Some strains produce alginate, a polysaccharide polymer that in hibits phagocytosis and contribtes to infection potential in patients with cystic fibrosis. Can survive harsh environmental conditions and displays intrinisic resistance to a wide variety of antimicrobial agents that facilitate the organisms ability to survive in the hospital setting.
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Know melioidosis.
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Melioidosis is an infectious disease caused by B. pseudomallei that has several forms, including formation of skin abscesses, sepsis and septic shock, abcess formation in several internal organs and acute pulmonary disease.
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Conventional tests that are used to identify Pseudomonas aeruginosa.
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Oxidase -positive, Triple sugar iron slant with an alkaline/no change (K/NC) reaction, good growth @ 42 degrees C, Production of bright bluish-green, red, or brown diffusible pigment on Mueller-Hinton agar or trypticase so agar. To distinguish P. aeruginosa in the group of fluorescent pseudomonads by its ability to grow at 42 degrees
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Pseudomonas, Burkholderia, Ralstonia and Acidovorax are all members of the genus species that share what similar characteristics:
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They are aerobic, straight, and slender gram-negative bacilli whose cells range from 1 to 5 um in length and 0.5 to 1 um in width. All species except B. mallei are motile. Use a variety of charbohydrate, alohol and amino acid substances as carbon and energy sources. Able to survive and possibly grow at relatively low temperatures the optimum temp range for growth of most species is between 30 and 37 degrees C, that is they are mesophillic.they are all oxidase positive, grown on MacConkey agar and utilize glucose oxidatively.
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Pseudomas Epidemiology
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Survives in various environments in nature and in domestic environments such as hot tubs and hospitals. , rarely part of normal flora of healthy individuals , spread by ingestion of contaminated food and water exposure to contaiminated medical devices , by penetratng wounds or person to person.
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Spectrum of Disease
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Opportunistic pathogen that requires compromised host defenses to establish infection. In normal healthy hosts infection is usually associated with events that disrupt or bypass protection provided by the epidermis, which result in CA infections such as skin, external ear canal, eye, bone heart and respiratory tract. or HA infectiongs such as respiratory tract , urinary tract wounds bloodstream and central nervous system. Key pathogen to infect cystic fibrosis patients.
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Burholderia cepcia Epidemiology and Pathogenicity
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Found in the evironment (soil water plants, survives well in hospita not part of normal human flora nay colonize respiraory tract of patients with cystic fibrosis, Exposure to medical devices and solutions contaminated from the environment person to person transmission. Nonpathogenic to healthy human hosts able to colonize and cause life threatening infections with cysistic fibrosis or chronic granulomatous disease.other patients may suffer nonfatal infections of the urinary tract, respiratory tract and other sterile body sites
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What is the natural habitat of Achromobacter group?
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Uncertain,probably environmental not part of human flora and the mode of transmission is unknown and rarely found in humans.
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Most common infections for Rhizobium radiobacter
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Exposure of immunocompromised or debilitated patient to contaminated medical devices resulting in bacteremia and less commonly periotonitis, endocarditis, or urinary tract infection.
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Most common infections for Ochrobactrum anthropi
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Catheter and foreign body-associated bacteremia .May also cause pyogenic infetions, community-acquired wound infections and meningitis in tissue graft recipients. Patients are usually immunocompromised or otherwise debilitated.
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What is the natural habitat of Rhizobium radiobacter?
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Environmental soil and plants not part of human flora
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what is the natural habitat of Psychobacter immobilis?
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Environmental particularly cold climates such as the Antarctic; not part of human flora
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What is the natural habitat of Paracoccus yeei?
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Environmental, not part of human flora
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What are the general characteristics of Achromobacter, Rhizobium, Ochrobactrum and similar organisms?
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All are non pigmented, oxidase positive and oxidize glucose; most grown on MacConkey agar howver, their specific morpholgic and physiologic features are somewhat diverse.
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Valid or invalid susceptibillity testing
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Validated susceptibility testing methods do not exist for these organisms. Although many of these organisms will grow on the media and under the conditions recommended fo testing the more commonly encountered bacteria the ability to grow and the ability to detect important antimicrobial resistances are not the same thing. therefore the lack of validated in vitro susceptibility testing methods does not allow definitive treatment and testing guidlines to be given for any of the organisms. Although susceptibility data for some of these bacter can be found in the literature, the mechanisms prohibits the validating of such data.
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What are the general characteristics of Cryseobacterium, Sphingobacterium and similar organisms?
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Most are yellow pigemented, oxidase positive glucose oxidizers that grow o MacConkey agar.
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What is the natural habitat for Chryseobacterium, Sphingobacterium, Agrobacterium and Empedobacter ?
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They are found in soil;plants;water;foodstuffs;hospital water sources, including incubators, sinks, facets, tap water, hemodialysis systems, saline solutions and other pharmaceuticals. Not part of human flora. Spread by exposure to contaminated medical devices or solutions but source is not always known. May colonize upper respiratory tract. C. meningospeticum occasionally may be transmitted from birth canal to neonate
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What is the mode of transmission for Bordtella bronchiseptica?
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Probably by exposure to contaminated respiratory droplets during close contact with animals
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What is the gram stain appearance of Bordtella?
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medium-sized straight rods
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What is the mode of transmission for Achromobacter denitrificans?
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Not often known. Usually involves exposure to contaminated fluids, soaps and disinfectants
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What are the general characteristics of Bordtella, Alcaligenes, Comamonas and similar organisms?
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Are gram negative, oxidase positive, are nonglucose users (asaccharolytic), Exhibit growth on MacConkey agar. Are motile except for O. urethralis is nonmotile.
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What is the natural habitat of Achromobacter and most common infection?
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Environment, including moist areas of hospital. Transient colonizer of human gastrointestinal or respiratory tract of patients with cystic fibrosis. Infections usually involve compromised patients and include bactermia, urinary tract infections, meningitis, wound infections , pneumonia, and peritonitis, and occur in various body sites, can be involved in nosocomial outbreaks.
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What is the natural habitat of Alcaligenes faecalis and common infection?
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environment soil and water, including moist hospital environments may transiently colonize the skin. Infections usually involve compromised patients. Often a contaminant;clinical significance of isolates should be interpreted with caution. Has been isolated from blood, respiratory and urine specimens. It associated with bacteremia, pancreatic abscesses, and ocular, bone and urinary and ear infections.
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What is the natural habitat of Bordtella and common infections?
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Normal respiratory flora of several mammals, including dogs, cats and rabbits not part of human flora, Opportunistic infection in compromised patients with history of close animal contact. Infections are uncommon and include pneumonia, bacteremia, urinary tract infections, meningitis and endocarditis.
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What are Myroides spp?
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Myroids spp, are pleomorphic rods and are either short or long and straight to slightly curved. and is distinguished by the Urea hydrolysis test and its fruity odor. Grows well on 5% SBA, chocolate and MacConkey agars. Most colonies on SBA are yellow, and tend to spread, on MAC it is a Non Lactose Fermenter.Nitrate reduction is variable.
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What is the Cholera toxin (CT) ?
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Cholera toxin is primarily responsible for the key features of cholera, release of this toxin causes mucosal cells to hypersecrete water and electrolytes into the lumen of the gastrointestinal tract. The result is profuse water diarrhea, leading to dramatic fluid loss.
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Other toxins of Vibrio Cholerae?
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Zot toxin, Ace toxin, Somatic antigens 01 and 0139 are associated with the cell envelope are postive markers for strains capable of epidemic and pandemic spread of the disease. Motility and chemotaxis mediate the distribution of organisms and mucinase production allows for penetration of the mucous layer. TCP pili provide the means by which bacilli atach to mucosal cells for release of the cholera toxin.
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What is the media of choice for Vibrio spp.?
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Stool cultures for Vibrio spp. are plated on the selective medium THIOSULFAE CITRATE BILE SALTS SUCROSE (TCBS) agar. Those that grow well produce either yellow or green colonies, dependin on whether they are able to ferment sucrose (produce yellow colonies) Alkaline peptone water (ph 8.4) may be used as an enrichment broth for obtaining growth of virbios from stool. AFter incubation, the broth is incubated for 5 to 8 hours at 35 degrees C. and then subcultured to TCBS.
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What are the symptoms of Virbio cholerae?
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severe, profuse watery diarrhea accompanied by vomiting, which can quickly lead to dehydration and hypotension
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What is the general characteristics of the Vibrio, Aeromonas, Plesimonas and Chromobacterium organisms?
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They are all oxidase positive, glucose fermenting, gram-negative bacilli that grow on MacConkey agar, halophilic
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What is the general habitat for these species?
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Brackish water or salt water
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What is the habitat of Vibrio cholerae and mode of transmission?
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Niches outside the gastrointestinal tract, may survive in a dormant state in brackish or salt water, human carriers also are known but are not common, Spread by fecal oral route by ingestion of contaminated washing swimming cooking or drinking water also by ingestion of contaminated shellfish or other seafood
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What is the habitat of Aeromonas spp and mode of transmission?
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Aquatic environments around the world including fresh water, polluted or chlorinated water, brackish water and occasionally marine water, may transiently colonize gastrointestinal tract and often infect various warm and cold blooded animal species, ingestion of contaminated food dairy meat and produce or water exposure of disrupted skin or mucosal surfaces to contaminated water or soil traumatic inoculation of fish fins or fishing hooks.
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What is the habitat of Plesimonas shigelloides and mode of transmission?
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Freshwater especially in warmer climates, ingestion of contaminated water or seafood exposure to cold blooded animals such as amphibia and reptiles
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What is the habitat of Chromobacterium voilaceum and mode of transmission?
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environmental soil and water of tropical and subtropical regions, not part of normal human flora Exposure of disrupted skin to contaminated soil or water.
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