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42 Cards in this Set
- Front
- Back
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Cystitis agents
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Escherichia coli
Klebsiella, Proteus, Staphylococcus saprophyticus, Serratia marcescens, Pseudomonas aeruginosa, Enterococcus faecalis |
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Virulence factors
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Adherence to vaginal and uroepithelial cells
Cytotoxic, necrotizing factors Hemolysin Genes: pathogenicity islands |
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Pathogenicity islands
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Mobile genetic elements encoding virulence proteins such as:
Fimbriae, Pili, Outermembrane proteins (These are surface components mediating colonization and attachment) |
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Escherichia coli
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Produces a dry, pink colony on MacConkey - Lactose fermenter
Adhere to mucosa via pili Causes tissue damage Endotoxin (LPS) causes inflammation Treatment: penicillin, ciprofloxacin |
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Proteus vulgaris, Proteus mirabilis
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Gram-negative rods, facultative anaerobes
Opportunistic pathogens: Transmitted via catheters Urease positive Highly motile and swarm across agar media |
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Proteus mirabilis
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Second only to Escherichia coli - UTI
Will infect the kidneys > E. coli |
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Proteus mirabilis
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Pore-forming hemolysins
Endotoxin Urease Adhesins Polysaccharide capsules Pili, fimbriae, flagella Swarming abilities Biofilm formation |
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Tx of Proteus mirabilis
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Para-nitrophenyl glycerol (PNPG)
(Anti-swarming agent; Inhibits expression of virulence factors: Hemolysins, Proteases, Flagella; inhibits invasion of urothelial cells) |
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Staphylococcus saprophyticus
Biochemical attributes |
Nitrite negative
Nonhemolytic (γ-hemolysis) Catalase positive Coagulase negative Resistant to novobiocin "honeymoon cystitis" |
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Serratia marcescens
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Gram-negative bacilli
Facultative anaerobe Belongs to the Enterobacteriaceae family Positive for DNAse, Gelatinase, Lipase, Citrate utilization |
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Enterococcus faecalis
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Closely related to Group D streptococci
Streptococcus faecalis GI tract normal flora Causative agent for Endocarditis, Cystitis, Wound infections |
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Enterococcus faecalis
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Growth on Blood agar (g-hemolysis & Some a-hemolysis), Bile-esculin agar (Black discoloration), 6.5% NaCl
Catalase negative |
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Unique attribute to enterococcus faecalis
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25% of genome is exogenously acquired DNA through lateral gene transfer between the genus and species --> Development of antibiotic resistance
Acquired from Staphylococcus and Streptococcus |
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leading causes of hospital-acquired infections
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Enterococcus faecalis
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Enterococcus faecalis Pathogenicity island
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Produce toxin that forms holes in cell wall & Adherence
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Treatment Enterococcus faecalis
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Amoxicillin
Ampicillin Vancomycin - Resistance to this antibiotic is appearing in Enterococcus faecalis |
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Klebsiella sp.
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Gram-neg, non-motile, rod-shaped, aerobic
Form large, mucoid colonies - K antigen --> Protects microorganism from phagocytosis & Aids in adherence |
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Catheter-associated UTIs
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Escherichia coli
Klebsiella Proteus Enterococcus sp. Pseudomonas cepacia ** Enterobacter Serratia marcescens ** Candida Serratia marcescens and Pseudomonas cepacia do not commonly reside in the gastrointestinal tract |
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Schistosoma haematobium
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Can lead to renal failure due to Obstructive uropathy, Pyelonephritis, Bladder carcinoma
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Female genital schistosomiasis
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Schistosoma haematobium causes lesions in lower female genital tract
May facilitate the spread of STDs such as HIV and HPV |
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urinary schistosomiasis Dx
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UTI caused by Salmonella sp. is suspicion for urinary schistosomiasis
UA, blood cultures, Urine cultures CBC: Check for anemia and eosinophilia Egg viability test |
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Urinary Schistosomiasis
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Praziquantel
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UA
Color and clarity |
Red-brown – hemoglobin
Yellow-brown to green – bile pigment Black-brown – melanins Dark brown to red – porphyrins Drugs, foods, and dyes produce different colors |
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What is positive in UA w/ UTI specimen?
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protein, blood, leukocytes, nitrites
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Nitrite
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Some (not all) bacteria convert nitrate to nitrite
Usually Gram-negative such as Pseudomonas, Escherichia, Citrobacter, Salmonella, Shigella, Klebsiella, Proteus |
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Leukocytes
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Dipstick method detects leukocyte esterase activity in WBCs (granulocytic cells)
Detects both lysed and intact WBCs |
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UTIs: Treatment
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Trimethoprim-sulfamethoxazole, Amoxicillin
Fluoroquinolones - Levaquin |
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UTI: tx Chlamydia trachomatis, Mycoplasma hominis
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Tetracycline, doxycycline
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Recurrent UTIs
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nonsecretors for certain blood group antigens are at risk for recurrent UTIs
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Escherichia coli
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Gram-negative bacillus, facultative anaerobe
Common isolate from the colon flora Produces a dry, pink colony on MacConkey - Lactose fermenter Reduce nitrate to nitrite |
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Escherichia coli antigens
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Possess O, H, and K antigens
K – capsular antigen, heat labile H – flagellar antigen, heat labile O – somatic antigen (cell wall), heat stable |
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Escherichia coli biochemistry
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Ferments glucose, lactose, trehalose, xylose
Positive indole, and methyl red tests Negative H2S production Negative DNase, urease, phenylalanine deaminase activity Cannot use citrate as sole carbon source Negative Voges-Proskauer |
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Staphylococcus saprophyticus
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Catalase-producing, gram positive cocci
Can appear singly, in pairs, and in clusters (“grapes”) Non-motile, facultative anaerobe Coagulase-negative Associated with urinary tract infections in young, sexually active females Able to adhere more effectively to the epithelial cells lining the urogenital tract |
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Klebsiella sp.
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Possesses polysaccharide capsule
Moist, mucoid colonies Urease positive Ferments inositol with gas production Utilize citrate as sole carbon source Ferments glucose with gas production (Lactose, sucrose, mannitol, maltose, xylose) DNAse negative Reduce nitrate to nitrite Involved with immunocompromised hosts Wound, UTI, bacteremia Absence of motility Distinguishes from other enterics |
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Proteus sp.
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Gram-negative bacilli, Motile
Two most widely recognized pathogens: Proteus mirabilis, Proteus vulgaris Isolated from urine, wounds, ear, bacteremic infections Produces hydrogen sulfide Urease positive Methyl red positive Gelatin hydrolysis Ferments glucose, xylose Reduce nitrate to nitrite |
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Enterococcus sp.
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Positive for bile esculin
Grows in 6.5% NaCl PYR+ |
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Enterobacter sp.
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Gram-negative bacilli
Two most common species isolated Enterobacter cloacae, Enterobacter aerogenes Both isolated from wounds, urine, blood, CSF Motile Urease negative Voges-Proskauer positive Methyl red negative Utilize citrate as sole carbon source Ferments glucose with gas production (Lactose, sucrose, mannitol) DNAse negative Reduce nitrate to nitrite |
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Candida albicans
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Main cause of yeast infection in the world
Germ tube production – positive Negative for potassium nitrate assimilation Negative for urease Cornmeal agar morphology – Forms true hyphae and pseudohyphae |
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Candida glabrata
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Infections associated with this – aggressive, difficult to treat
Second to Candida albicans |
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Candida parapsilosis
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Associated with nosocomial infections
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Serratia marcescens
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Member of Enterobacteriaceae family
Opportunistic pathogen a/w nosocomial infections (Urinary tract, respiratory tract, Bacteremia in nurseries, cardiac surgery, burn units, Contamination of antiseptic solution used for joint injections, Septic arthritis) Positive for DNAse activity Characteristic red pigmented colonies when grown at room temperature Gram-negative rods Gelatinase positive Lipase positive Citrate utilization |
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Pseudomonas cepacia
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Gram-negative rods
Low-grade, nosocomial pathogen A/w pneumonia in CF patients, Causes endocarditis, pneumonitis, urinary tract infections, osteomyelitis, dermatitis, wound infections due to use of contaminated water Isolated from irrigation fluids, anesthetics, nebulizers, detergents, disinfectants Utilizes glucose, maltose, lactose mannitol: DOES NOT FERMENT Oxidase and catalase positive Motile: Polar tufts of flagella Nonfluorescing: Produces nonfluorescing, yellow or green pigment |
