UTI Flashcards
Defense mechanisms against urinary tract infection
Flushing of urine
Physical barrier
Acidic pH
Antimicrobial substances
Desquamation
Sterile parts of urinary tract
Kidneys, ureters, and bladder
Normal flora of urethra
S epidermidis
Enterococci
Diphtheroids
Coliforms
Candida
Groups at risk for asymptomatic UTI
Elderly
Pregnant
Children
What causes a complicated UTI?
Structural, functional, and/or metabolic abnormalities
Viruses that may cause UTI
Adenovirus
BK polyoma
CMV
Fungi that may cause UTI
Candida
Histoplasma capsulatum –> descending
Parasite that may cause UTI
Schistosoma hematobium
Motile, gram negative bacilli that ferments lactose.
E coli
Virulence factor of E coli that contributes to development o sepsis
Endotoxin –> Lipid A of lipopolysaccharide (LPS)
Highly motile, flagellated, gram negative, pleomorphic bacilli. Grows in confluent films and does not ferment lactose. Positive for urease.
Proteus mirabilis
Virulence factor that mediates sepsis in Proteus UTI
Endotoxin (LPS)
Gram negative, motile, oxidase positive bacilli that does not ferment lactose. Produces pyocyanin and pyoverdin pigments.
Pseudomonas aeruginosa
UTI causing bacteria that can form biofilms in catheters. It does not ferment lactose.
Pseudomonas aeruginosa
Virulence factor of pseudomonas aeruginosa that inhibits protein synthesis by interfering with EF-2
Exotoxin-A
Gram positive, catalase negative, PYR positive, spherical or oval cocci in pairs at acute angles. Non-hemolytic, resistant to bile salts, and hydrolyzes esculin. Resistant to NaCl and high temp.
Enterococcus fecalis and fecium
What antibiotics work for antibiotic resistant enterococcus species?
Oxacillin
Cephalosporin
Gram positive, catalase positive, coagulase negative cocci in clusters. Resistant to novobiocin.
Staph saprophyticus
Endemic areas for Schistosoma
Africa
Middle East
Japan
Infective form of Schistosoma
Cercaria –> larval form that penetrates skin
Intermediate host of Schistosoma
Snail
Cytokines that respond to Th2 to induce production of IgE and eosinophils in response to helminth infection
IL-4
IL-5
IL-13
IL-10
Risk with chronic cases of Schistosomiasis
SCC of bladder
Cytokines responsible for granuloma formation and intense fibrosis in Schistosomiasis
IL-4 and IL-13
icosahedral, naked, dsDNA virus with penton fibers. Rare cause of UTI associated with hemorrhagic cystitis.
Adenovirus
Cut of pathologic pyuria
> 5 PMNs/hpf
What is suggested by UTI symptoms with sterile pyuria and negative culture?
Chlamydial or mycobacterium infection
Collected after start of antibiotics
What is indicated by positive nitrites on UA?
Infection with gram negative organism
What is the cut of for significant bactiuria?
> /= 10^5 CFU/mil of single pathogen
When does asymptomatic, but significant, bacteriuria require treatment?
Pregnancy
Treatments for uncomplicated cystitis
Nitrofurantoin
Trimethoprim-sulfamethoxazole
Fosfomycin
Pivmecillinam
Augmentin –> enterococci
Treatments for complicated UTI (pyelonephritis)
Fluoroquinolone (levofloxacin or ciprofloxacin)
IV Ceftriaxone
Trimethoprim-sulfamethoxazole
Specific treatment required for perinephric abscess with UTI
Surgical drainage
