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37 Cards in this Set
- Front
- Back
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Gram negative opportunistic pathogens
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E. coli, Klebsiella pneumonia, Serratia marcescens, Enterbacter cloacae, Proteus mirabilis, Legionella pneumophila, Pseudomonas aeruginosa
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These pathogens show less specialized adaptations to the host than other pathogens
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Opportunistic pathogens
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Nosocomial infections
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Hospital-aquired infections. 65% of them involve biofilm formation
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Most of this general type of bacteria form biofilms
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Gram negative opportunistic pathogens
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Diseases caused by E. coli
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Gastrointestinal infections, urinary tract infections (UTIs), bacteremia, meningitis
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Virulence factors of E. coli
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Capsular antigen (important in neonatal meningitis), pili, exotoxin, cell-surface adhesins (eg, mannoside binding in UPEC)
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UPEC
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Uropathogenic E. coli. Causes UTIs. Capable of intracellular growth (in urinary tract epithelium)
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This bacteria causes 95% of all non-hospital acquired UTIs
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Uropathogenic E. coli
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Cystitis
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Syndome involving dysuria (burning pee), frequency, urgency and occasional suprapubic tenderness. No fever, contrast to pyelonephritis. Typical of LOWER urinary tract infections, but may also include UPPER
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Mannosides
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Important cell surface molecule of uroepithelial cells that are binding targets for UPEC
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Acute pylenophritis
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Results when UTI disseminates to kidney. Syndrome involving flank pain, tenderness, fever, dysuria, frequency and urgency
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Type 1 pili
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Notable for being mannose sensitive. Found in UPEC
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UPEC E. coli adhesins
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P pili and F adhesin can cause pyelonephritis. Prs, Type 1, S pili and Dr adhesin can cause cystitis. Only Type 1 pili are mannose sensitive.
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P pili
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Feature of UPEC, causes pyelnephritis. Attaches to P blood group globoseries Gal-Gal constituents of glycolipids on uroepithelia cells and erythrocytes. Coded by an OPERON
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Stochastic switching
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"Phase variation". Epigenetic and genetic phenotypic trait changes contributing to diversity and survival of a species of bacteria.
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Gram-negative bacteremia
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Main cause is E. coli. Systemic reaction to endotoxin (LPS). Septic (endotoxic) shock.
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Leading cause of neonatal meningitis
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E. coli
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K1 capsule
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Virulence factor of some E. coli. Nearly identical to the meningococcal capsule. Consist of sialic acids, which are also present in host cells and therefore are poor antigenic determinants.
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Klebsiella pneumoniae
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Red capsule. Non-motile. Causes primary pneumonia in alocholics, diabetics, etc. Also a cause of meningitis, bacteremia, etc.
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Enterobacter cloacae
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Contrast to Klebsiella: motile, thinner capsule. Associated with burn, wound, respiratory and urinary tract infections. With E. agglomerans, associated with IV tubing contamination affecting hundreds of patients in 25 hospitals.
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Proteus vulgaris, Proteus mirabilis
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Frequent cause of UTI. A notable feature is UREASE SYNTHESIS that can raise the pH of urine to precipitate salt and stone formation in the urinary tract in chronic infections
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Serratia marcesens
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Pneumonia. Less likely to colonize GI tract than other enterobacteriaceae. More associated with URINARY TRACT and RESPIRATORY TRACT. Associated with HEROIN addicts. Also associated with SEPTIC ARTHRITIS. Can produce IgA-specific proteases.
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Pseudomonas aeruginosa
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FORMS BIOLFILMS--the model organism for studying biofilms. Gram negative, obligate aerobe (cannot ferment sugar, but can grow via anaerobic resp. with nitrate instead of oxygen), opportunistic bacteria. Able to grow at temperatures as low as 4 C. Causes acute and chronic infections. Acute: Bacteremia (immunocompromised patients), eye infections, burn infections. Chronic: respiratory infections.
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This bacteria can grow at temperatures as low as 4 C
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Pseudomonas aeruginosa
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This bacteria has a high natural resistance to many of the antibiotics used to treat other gram negative pathogens
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Pseudomonas aeruginosa
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Exotoxins secreted by P. aeruginosa
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ExoA: Stops protein synthesis by ribosylating EF-2; ExoS and ExoT: Stops host regulatory proteins by ribosylating them; ExoU: Destroys cell membranes by its phospholipase activity. Elastase, phospholipase. Alginate: capulse giving strains a mucoid appearance; blocks phagocytosis
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Alginate
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Capsule of P. aeruginosa that is produced in chronic infection. Block phagocytosis like capsules normally do.
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This is the model organism for studying biofilms
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Pseudomonas aeruginosa
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Legionella pneumophila
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Causes Legionaire's disease--a potentially fatal pneumonia. Identified recently in 1976.
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This bacteria is most frequently found in the water of cooling towers, and resides within free-living amoeba
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Legionella pneumophila
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Gram negative, pleomorphic rod. Exhibits intracellular growth
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Legionella pneumophila
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Incubation period of Legionaire's disease
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2-10 days
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Transmission of Legionaire's disease
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NOT person-to-person, but via the airborne route from environmental contamination
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Legionaire's disease
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Pneumonia, though most infections are probably clinically insignificant ("cold symptoms"). Other symptoms are fever, chills, and a dry or productive cough, diarrhea, muscle aches, etc. therefore it is difficult to distinguish from other types of pneumonia.
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The reservoir for this bacteria includes stagnant water in air conditioning and heating units
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Legionella pneumophila
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Diagnosis of Legionaire's
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Detection of bacteria in sputum; antigens in urine; or increased antigens against convalescent blood
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These gram negative opportunists are lactose positive
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E. coli, Klebsiella pneumonia, Enterbacter cloacae
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