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59 Cards in this Set
- Front
- Back
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Describe Pseudomonas aeruginosa biochemically.
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Gram-negative, non-sporulating bacillus
Obligate aerobe except with nitrate Does not ferment carbohydrates Oxidase positive Appears blue-green due to pyocyanin May produce a mucoid exopolysaccharide (alginate) – cystic fibrosis patients |
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What are potential reservoirs of P aeruginosa?
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flowers, uncooked vegetables, hospital sinks, medical equipment
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Is p aeruginosa CAP or nosocomial?
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nosocomial
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What are predisposing factors for p. aeruginosa?
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Immunosuppression
Hematologic malignancies Intensive care unit Trauma Drug addiction Surgery Cystic fibrosis Prolonged hospitalization Thermal Injury Mucosa injury *AN INFECTION OF THE DEBILITATED* |
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Where does p aeruginosa colonize?
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can adapt to almost any damp environment
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What are the p aeruginosa cellular virulence properties?
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pili - mediate attachment
alginate - mediate attachment, block phagocytes outer cell membrane - block phagocytes, barrier to antibody and complement flagella - motility endotoxin - antiphagocytic, stimulates cytokine production |
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What are the p aeruginosa extracellular virulence properties?
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elastase - dissolution of lamina propria
alkaline protease - corneal, alveolar necrosis exotoxin a - inhibit protein synthesis, cellular necrosis exoenzyme s - inhibit protein synthesis, promotes dissemination pyoverdin - scavenges iron pyocyanin - produces reactive oxygen species |
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How does p aeruginosa's exotoxin a work?
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adenosine diphosphoribosyl transferase which targets EF-2 to inhibit protein synthesis and cause tissue necrosis
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What are community acquired clinical syndromes of p aeruginosa?
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otitis externa (malignant otitis externa), whrilpool folliculitis, ulcerative keratitis, "sneaker osteomyelitis", endocarditis, cystic fibrosis
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What are hospital acquired clinical syndromes of p aeruginosa?
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UTI, pneumonia, bacteremia, typhilitis, meningitis, soft tissue, burns
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What are cutaneous infections of p aeruginosa?
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paronychia (green nail syndrome), toe web infections, pyoderma, cellulitis, ecthyma gangrenosum, subcutaneous nodules, burn would sepsis
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What are the ear infections caused by p aeruginosa?
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otitis externa, malignant otitis externa, chronic
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How does malignant otitis media present
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elderly diabetics with pain, edema, tenderness of soft tissues with pirulent discharge
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What is Whirlpool folliculitis?
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p aeruginosa serogroup O:11
caught from hot tubs (not pools) diffuse, pruritic, maculopapular area covered by bathing suit and apocrine sweat glands |
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What is affected in malignant otitis media?
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the bone-cartilage junction, midway down the ear canal
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Which group is associated with p aeruginosa bone and joint infections?
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iv drug users
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What are the GI infectinos caused by p aeruginosa?
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Typhilitis--necrotizing cecal infection in neutropenic patients
Perirectal abscess--neutropenic patients Diarrheal disease--in children Shanghai fever--mimics enteric fever |
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Who does bacteremia caused by p aeruginosa affect?
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icu patients, neutropenic cancer patients, burn wound patients, aids patients receiving certain meds, and ivdu's with endocarditis
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What are the difficulties in managing pseudomonas infections?
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the host is usually debilitated
microbial virulence factors antibiotic resistance |
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What does p aeruginosa make to resist antibiotics?
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beta-lactamase
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What is cystitis?
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an infection of the bladder
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What is pylonephritis?
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an infection of the kidney
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What are the predisposing factors for UTIs?
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short urethra in females
obstructions (ex. bph, prostatic cancer, etc.) neurogenic bladder (doesn't properly contract) pregnancy catheterization |
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What are the genitourinary host defenses?
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Bladder washout
Antibacterial properties of urine (low pH, high urea, high osmolality) Tamm-Horsfall protein (Binds to E. coli and prevents epithelial cell attachment) Bladder mucopolysaccharides Vaginal pH, IgA?, flora? TLR11--recognizes bacterial polysaccharides (Absence of TLR11--increased incidence of pyelonephritis) |
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What is the pathogenesis of UTIs?
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99%: rectal flora -> perineal colonization -> vaginal colonization -> colonization of urethra -> up urethra -> up bladder -> up kidney
1%: through the blood |
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what is introital colonization?
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colonization at the opening of the urethra in women
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What are the microbial virulence factors found in bacteria which cause UTIs?
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Adhesins (Mannose-sensitive -- bladder; Mannose-resistant and X adhesins -- pyelo)
Serum bactericidal resistance Increased K antigen Presence of aerobactin Presence of hemolysin |
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What is the most common cause of UTIs?
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e coli
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Which coag negative staph cause UTIs?
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s epidermidis and s saprophyticus
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How does a uti from s epidermidis occur and how is it treated?
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M=F, >50 years, multidrug resistant, relapse common, 90% asymptomatic
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How does a uti from s saprophyticus occur and how is it treated?
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95% female. 16-35 years old, sensitive to therapy, relapse rare, 90% symptomatic
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How does the immune response protect against UTIs?
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it doesn't; even individuals without humoral responses arent more predisposed to UTIs
risk is based on anatomic factors |
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How can a UTI be diagnosd?
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clinical syndrome, microscopic examinatino of urine, biochemical tests, culture
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How does a UTI present in children?
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fever, GI symptoms, failure to thrive
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How does a UTI present in adults?
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dysuria (burning of urine), urgency, more frequent urination, suprapubic tenderness in cystitis, more fever and flank tenderness in pylonephritis
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How is a UTI diagnosed microscopically?
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pyuria (white cells in urine)
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What biochemical tests can be used for UTIs?
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leukocyte esterase
nitrite tests detect reduction of nitrate to nitrite by enterobacteriaceae |
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What are complicatinos of UTIs?
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Bacteremia
Perinephric Abcess - abcess along renal papillae Emphysematous pyelonephritis - gas in the kidney Xanthogranulomatous pyelonephritis Papillary Necrosis |
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What are the treatment principles of cystitis?
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Most infections caused by E. coli
Culture often not necessary in healthy women Short course (3 days) usually effective |
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What are the treatment principles for pyelonephritis?
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E. coli, Klebsiella, Proteus
Cultures should be obtained Treat for 10-14 days Hospitalize for GI symptoms, or if severely debilitated. |
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When should bacteriuria always be treated?
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in pregnant women
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What are predisposing factors to UTIs?
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Incomplete Bladder Emptying: (Pelvic relaxation with cystocele, Bladder Diverticula, Neurogenic Bladder)
Urinary Obstruction: (Meatal stricture, Urethral stricture, Prostatic enlargement, Bladder neck obstruction) Vesicoureteral reflux Stones |
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What is prostatis?
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an infection of the prostate which usually ascends through the urethra
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What are the symptoms of acute prostatits?
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high fever, chills, perineal and back pain, UTI symptoms
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What is found on examination with acute prostatitis?
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Warm, swollen, exquisitely tender
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What are predisposing factors to UTIs?
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Incomplete Bladder Emptying: (Pelvic relaxation with cystocele, Bladder Diverticula, Neurogenic Bladder)
Urinary Obstruction: (Meatal stricture, Urethral stricture, Prostatic enlargement, Bladder neck obstruction) Vesicoureteral reflux Stones |
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What usually causes acute prostatits?
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N. gonorrhoeae, E. coli, other GNRs
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What is prostatis?
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an infection of the prostate which usually ascends through the urethra
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What are the symptoms of chronic prostatitis?
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Asymptomatic to perineal discomfort, low back pain, dysuria
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What are the symptoms of acute prostatits?
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high fever, chills, perineal and back pain, UTI symptoms
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What is found on examination with chronic prostatitis?
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Normal to mild tenderness
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What is found on examination with acute prostatitis?
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Warm, swollen, exquisitely tender
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What usually causes chronic prostatits?
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Bacterial—E. coli, other GNRs, enterococci
Non-bacterial—Chlamydia, Ureaplasma? others |
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What usually causes acute prostatits?
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N. gonorrhoeae, E. coli, other GNRs
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What is the treatment for prostatitis?
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antibiotic penetration is difficult and treatment is usually prolonged; tetracyclines, quinolones have good penetrastion
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What are the symptoms of chronic prostatitis?
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Asymptomatic to perineal discomfort, low back pain, dysuria
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What is found on examination with chronic prostatitis?
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Normal to mild tenderness
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What usually causes chronic prostatits?
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Bacterial—E. coli, other GNRs, enterococci
Non-bacterial—Chlamydia, Ureaplasma? others |
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What is the treatment for prostatitis?
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antibiotic penetration is difficult and treatment is usually prolonged; tetracyclines, quinolones have good penetrastion
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