Module 8: SSTI / UTI Flashcards
- Involves any layer (epidermis, dermis), subcutaneous fat, fascia, or muscle
- Can be mild and self-limiting to severe-progressing to complicated infections (septic arthritis, osteomyelitis, bacteremia, endocarditis, etc.)
- Empiric treatment based on severity and site of infection, patient underlying disease, and probable etiology
SSTI (Skin and Soft Tissue Infections)
Factors that predispose to skin and soft tissue infection:
- High concentrations of bacteria (>105)
- Excessive moisture (eg obesity)
- Inadequate blood supply
- Availability of bacterial nutrients
- Damage to corneal layer allowing bacterial penetration
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Cell______
Definition: Acute inflammation and infection of skin and subcutaneous fat. This (which includes erysipelas) manifests as an area of skin erythema, edema, and warmth; it develops as a result of bacterial entry via breaches in the skin barrier.
Cellulitis
Predisposing factors of cell______:
Venous or lymphatic insufficiency, DM (or other immunosupressive states), alcoholism, obesity, breaks in the skin / skin trauma, pre-existing skin infections.
Cellulitis
Examples of presdisposing factors of cell______:
- Skin barrier disruption due to trauma (such as abrasion, penetrating wound, pressure ulcer, venous leg ulcer, insect bite, injection drug use)
- Skin inflammation (such as eczema, radiation therapy)
- Edema due to impaired lymphatic drainage
- Edema due to venous insufficiency
- Obesity
- Immunosuppression (such as diabetes or HIV infection)
- Breaks in the skin between the toes (“toe web intertrigo”); these may be clinically inapparent
- Preexisting skin infection (such as tinea pedis, impetigo, varicella)
Cellulitis
Signs and symptoms of c_________:
- erythema
- edema
- warm to touch
- diffuse tenderness
- indistinct border
- lymphadenopathy
Cellulitis
Common bacterial causes of cellu_____ (otherwise healthy):
Think skin flora (penetrating compromised skin), unless otherwise infectious source:
- Group A Streptococcus (GAS)(β hemolytic strep) - primarily S. Pyogenes
- S aureus (MSSA)
- S aureus (MRSA)
- Haemophilus influenzae (children)
Cellulitis
C_-M___: Causes serious infections in otherwise healthy persons who have not been recently hospitalized.
- Transmission of MRSA (complicated or uncomplicated disease) associated with minor skin trauma, sharing of sports or personal care equipment, sharing of close quarters, recent hospitalization or surgery, + others.
- No obvious risk factors, but associated with dermatological conditions, diabetes and smoking. NOTE treatment variation where CA-MRSA is suspect!
CA-MRSA
Complicated Cellulitis: Involves the immunocompromised, DM, vascular insufficient, use of injectable drugs, etc.
Complicated Cellulitis
Pathogens of complicated cellulitis:
Pathogens:
MSSA, HA-MRSA, CA-MRSA, Enterobacteriaceae, P aeruginosa, anaerobes
Predisposing factors increase risk of poly-microbial disease
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Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Mild cellulitis:
dicloxacillin, cephalexin, clindamycin
CA-MRSA suspected or allergy to PCN clindamycin, smz/tmp, doxycycline
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Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Mild cellulitis:
dicloxacillin, cephalexin, clindamycin
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Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Mild cellulitis:
CA-MRSA suspected or allergy to PCN clindamycin, smz/tmp, doxycycline
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Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Moderate-to-severe cellulitis:
nafcillin, cefazolin, clindamycin
CA-MRSA suspect or allergy to PCN: vanco, linezolid, daptomycin, ceftaroline, televancin
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Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Moderate-to-severe cellulitis:
nafcillin, cefazolin, clindamycin
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Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Moderate-to-severe cellulitis:
CA-MRSA suspect or allergy to PCN: vanco, linezolid, daptomycin, ceftaroline, televancin
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Oral ABT agents for treatment of MRSA infection in adults:
- clindamycin
- trimethoprim-sulfamethoxazole
- doxycycline
- minocycline
- linezolid
- tedizolid
- delafloxacin
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Regarding cell______:
Patient specific factors? Allergies, drug-drug/drug-disease interactions, pregnancy, children, etc…
Recall Examples:
- Avoid penicillins or cephalosporins in patients with history of hypersensitivity (type I) to these classes of medication
- DI with quinolones and mono- and di- valent cations (Ca, Mg, etc), iron
- Avoid “cyclines” (doxycycline, tetracycline) and quinolones in children
- Altered renal, hepatic, biliary functions
Cellulitis
If CA-MRSA is suspected (in cellulitis), clindamycin, SMZ-TMP, or doxycycline must be added to the treatment regimen.
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Hypersensitivity reactions occur when penicillin is degraded to penicilloic acid and other compounds that combine with proteins in the body to form antigens, which cause antibody formation.
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If hypersensitive to ABTs like penicillin:
- Use alternative antibiotic
- Skin testing can be done
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Cross-reactivity between Penicillins and cephalosporins or carbapenems ~ 3-7%
- Use alternative antibiotic in the case of prior anaphylaxsis
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Er_______s:
More superficial infection w/ very sharp, raised border, systemic sxs
Erysipelas
Necrotizing fasciitis:
- deep subcutaneous infection that causes necrosis of the fascia and subcutaneous fat with rapidly progressive inflammation.
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Necrotizing fasciitis:
Treatment of necrotizing infection consists of early and aggressive surgical exploration and debridement of necrotic tissue, together with broad spectrum empiric antibiotic therapy and hemodynamic support.
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Animal bites:
Most animal bites are caused by dogs, cats, and humans. The predominant organisms in animal bite wounds are the oral flora of the biting animal as well as human skin flora (such as Staphylococci and Streptococci).
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Animal bites:
Most animal bites are caused by dogs, cats, and humans. The predominant organisms in animal bite wounds are the oral flora of the biting animal as well as human skin flora (such as Staphylococci and Streptococci).
- Pasteurella multocida
- Prophylaxis - Prophylactic antibiotics reduce the rate of infection due to some animal bites, especially cat bites.
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Primary agent of choice for animal bites:
Amoxicillin-
clavulanate (Augmentin)
- 875/125 mg twice daily
- 20 mg/kg per dose (amoxicillin component) two times daily (maximum 875 mg amoxicillin and 125 mg clavulinic acid per dose)*
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Alternate empiric regimens include:
One of the following agents with activity against P. multocida:
- Doxycycline (Not recommended in children <8 years of age)
- TMP-SMX
- Penicillin VK
- Cefuroxime
- Moxifloxacin (Use with caution in children <18 years of age)
PLUS
One of the following agents with anaerobic activity:
- Metronidazole
- Clindamycin
Duration is 7 days.
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Imp_____:
Seen mostly in children, highly communicable, esp. in hot humid weather.
S. Pyogenes (β hemolytic strep), S. aureus
Treatment:
- May resolve on its own with non-pharmacological interventions
- Antistaphylococcal penicillins (eg dicloxacillin)
- 1st gen cephalosporin (eg cephalexin)
If MRSA is suspected or PCN allergy:
- Clindamycin, SMZ/TMP, Doxycycline
NOTE: tetracyclines (including doxycycline) should be avoided in children
Topical: Mupirocin or Bacitracin for nonbullous impetigo.
Impetigo
U__: Presence of microorganisms in the urinary tract that cannot be accounted for by contamination.
UTI
U__s and the Elderly:
- In older adults who are cognitively intact, the diagnosis of symptomatic UTI is relatively straightforward.
UTI
UTIs in the Elderly:
In older adults who suffer from significant cognitive deficits, impairing their ability to communicate, and chronic genitourinary symptoms (e.g., incontinence, urgency and frequency), this makes the diagnosis of symptomatic UTI in this group particularly challenging.
- Furthermore, when infected, nursing home residents are more likely to present with nonspecific symptoms, such as anorexia, confusion and a decline in functional status; fever may be absent or diminished. In the setting of atypical symptoms, providers are often faced with the challenge of differentiating a symptomatic UTI from other infections or medical conditions.
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Symptoms of frequency, dysuria, hesitancy, incontinence may not be diagnostic of UTI in the elderly.
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Additional diagnostic information (for all patients and when symptomology is unreliable):
- urinalysis: ≥ 105 cfu/ml (traditional definition).
- Nitrite reduction test: nitrite is formed by bacteria that reduce nitrate normally found in the urine; signifies the presence of bacteria (gm -)
- Leukocyte esterase: signifies presence of WBC’s (found in primary neutrophil granules); sensitive and specific for 10 WBC/mm3)
- Hematuria: microscopic or gross; nonspecific but commonly seen in infection
- Color, Turbidity, Specific gravity, etc
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Children and UTIs:
- Children with UTIs manifest different symptoms depending on age.
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Lower urinary tract infections: (cystitis, urethritis, prostatitis, epididymitis)
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Signs and symptoms of Lower Urinary Tract Infections:
- Frequency, urgency, dysuria
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Uncomplicated LUTIs:
occur in those who lack structural or functional abnormalities of the urinary tract; generally occur in females of childbearing age (15-45y) who are otherwise healthy.
- 85% are caused by Escherichia coli
- Treatment: Nitrofurantoin, SMZ/TMP, (quinolone)
- β-lactams can be used but generally regarded as less effective
- Short course (3 days) is usually sufficient.
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Complicated LUTIs:
occur as a result of predisposing lesion of the urinary tract, such as congenital abnormality, stone, indwelling catheter, distortion of the urinary tract, prostatic hypertrophy, obstruction, neurologic deficit that interferes with normal flow.
- 50% are caused by Escherichia coli
- Remainder caused by Proteus spp., Klebsiella pneumoniae, Enterobacter spp., Enterococcus spp., Pseudomonas aeruginosa, Staphylococcus
Treatment: Cefpodoxime, smz/tmp, quinolone.
- 7-14 day course
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Treatment considerations for LUTIs:
- Antibiotic spectrum
- Patient characteristics (Comp vs. Uncomp)
- Adverse effects
- Drug Interactions
- Other factors such as cost and compliance
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Recurrent infections (LUTIs):
- Most recurrent infections are reinfections (recurrence of different organism)
- 2 to 3 per year (treat each as they occur)
- More frequent infections—then consider prophylaxis
- Options?
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Asymptomatic bacteriuria is treated with an antibiotic tailored to the susceptibility pattern of the isolated organism, which is generally available at the time of diagnosis. Potential options include beta-lactams, nitrofurantoin, and fosfomycin. The choice of antimicrobial agent should also take into account safety during pregnancy (including the particular stage of pregnancy).
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Lower UTIs (Uncomplicated):
Bacteria: E Coli
Treatment:
- Nitrofurantoin
-SMZ/TMP
- Quinolones and B-lactams are efficiacious; use should be reserved to minimize resistance.
- 3-5 days of therapy is usually sufficient for women. Men are typically longer at 10-14 days.
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Lower UTIs (Complicated):
Bacteria: E Coli, S. saprophyticus, Enterococcus spp,
Pseudomonas , klebsiella, proteus spp, Enterobacter
Treatment:
- Cefpodoxime
- smz/tmp
- quinolone
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Phenazo________:
An azo dye with analgesic or local anesthetic effect on urinary tract mucosa/
- FDA approved for symptomatic relief of irritation of LUT mucosa
- dose 200 mg orally 3 times daily for maximum of 2 days
- dose 190 mg if using nonprescription 95 mg tablets
- take after meals
- turns urine bright orange and may lead to staining of undergarments
- contraindicated if renal disease or severe hepatitis
- discontinue if yellowish skin or sclerae (may suggest renal impairment)
- should not be used chronically
Phenazopyridine
C________ j____:
Contains proanthocyanidins which prevent fimbriated E. coli from adhering to uroepithelial cells in vitro.
- Insufficient evidence to recommend cranberry juice for treatment of UTIs.
Cranberry juice
Antibiotics for asymptomatic bacteriuria and cystitis in pregnancy:
- nitrofurantoin
- amoxicillin
- amoxicillin-clavulanate (Augmentin)
- cephalexin
- cefpodoxime
- fosfomycin
- trimethoprim/sulfamethoxazole
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Nitrofurantoin does not achieve therapeutic levels in the kidneys so should not be used if pyelonephritis is suspected.
(ABTs for asym. bacteriuremia/cystitis in pregnancy)
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Avoid using nitrofurantoin during the first trimester and at term if other options are available.
(ABTs for asym. bacteriuremia/cystitis in pregnancy)
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Resistance to amoxicillin may limit its utility among gram-negative pathogens.
(ABTs for asym. bacteriuremia/cystitis in pregnancy)
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Fosfomycin does not achieve therapeutic levels in the kidneys so should not be used if pyelonephritis is suspected.
(ABTs for asym. bacteriuremia/cystitis in pregnancy)
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Avoid using trimethoprim-sulfamethoxazole during the first trimester and at term.
(ABTs for asym. bacteriuremia/cystitis in pregnancy)
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Some antibiotics are safe through the entire pregnancy, some only during specific trimesters and some not at all. It is our responsibility to know this information and prescribe responsibly.
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Nitrofurantoin will not achieve adequate concentrations in the upper urinary tract.
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Upper urinary tract (acute pyelonephritis)
- Usually includes UTI symptoms. Plus: fever, chills, flank pain, N/V
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Upper UTI bugs:
E Coli, S. saprophyticus, Enterococcus spp, Pseudomonas , klebsiella, proteus spp, Enterobacter
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Mild pyelonephritis may be treated with oral therapy as an outpatient if sensitivity is known.
- SMZ/TMP or Quinolone
- Full doses needed for tissue penetration
- Treat for 14 days. Short course therapy (eg. 1 day, 3 day, etc) is not appropriate
- Ampicillin, amoxicillin and older sulfonamides are not considered reliable empiric therapy in this setting
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UTIs in men:
Considered a complicated infection and most often involves the prostate.
- Prostatic penetration of antibiotic and duration of treatment are very important
- Generally treat for 10-14 days (quinolones, SMX-TMP often used if gram negative and sensitive).
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Upper UTI - uncomplicated pyelonephritis:
Bacteria: E Coli, S. saprophyticus, Enterococcus spp,
Pseudomonas , klebsiella, proteus spp, Enterobacter
Treatment:
- Smz/tmp
- quinolone
For complicated disease and if MDR the use of vancomycin should be considered.
Penicillins/cephalosporins offer no major advantage and there is increasing resistance of E. coli to these agents.
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Factors determining antibiotic penetration
- Lipid solubility
- Ionization (unionized drugs cross the lipid barrier of prostatic cells)
- pH (prostate basic pH when inflamed, thus unionized drug crosses epithelial barrier, becomes ionized, and gets trapped because can’t get back across lipid barrier)
- Drugs therefore need to reach therapeutic concentrations in the prostate and cover bacteria causing infection (quinolones or SMX/TMP)
- Long-term suppressive therapy may be necessary
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Bacterial Prostatitis
Infection results in inflammation of the prostate gland and surrounding tissue.
Acute:
- High fever, chills, malaise, myalgia, localized pain (perineal, rectal, sacrococcygeal), frequency, urgency, dysuria, nocturia, retention
- Swollen, tender, tense, indurated prostate gland
- Bacteriuria
Chronic:
- Frequency, urgency, dysuria, low back pain, perineal/suprapubic pain
- Boggy, indurated (enlarged) prostate gland
- Bacteriuria
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Bacterial Prostatitis
Infection results in inflammation of the prostate gland and surrounding tissue.
Chronic:
- Frequency, urgency, dysuria, low back pain, perineal/suprapubic pain
- Boggy, indurated (enlarged) prostate gland
- Bacteruria
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Bacterial Prostatitis
Infection results in inflammation of the prostate gland and surrounding tissue.
Acute:
- High fever, chills, malaise, myalgia, localized pain (perineal, rectal, sacrococcygeal), frequency, urgency, dysuria, nocturia, retention
- Swollen, tender, tense, indurated prostate gland
- Bacteruria
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Primary treatment regimen of bacterial prostatitis.
Uncomplicated, with risk of STD (Age < 35 years):
- Ceftriaxone 250 mg IM x 1 dose
OR - Cefixime 400 mg po x 1dose
THEN
- Doxycycline 100 mg po bid x 10 days
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Primary treatment regimen of bacterial prostatitis.
Uncomplicated with low risk of STD:
ONE OF THESE:
- Levofloxacin 500-750 mg IV/po once daily]
- Ciprofloxacin (500-750 mg po or 400 mg IV) twice daily] x 10-14 days (minimum)
OR
- SMZ/TMP 1 DS tablet (160 mg of the TMP component) po bid x 10–14 days (minimum)
Some authorities recommend 4 to 6 weeks of therapy.
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Regarding ABT treatment of bacterial prostatitis:
Use of adjunctive uroselective alpha-adrenergicantagonists (e.g. tamsulosin, alfuzosin and silodosin) should be considered to reduce symptomatology (e.g., poor urinary stream, hesitancy).
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Cellulitis and erysipelas manifest as areas of thin erythema, edema, and warmth; they develop as a result of bacterial entry via breaches in the skin barrier. Cellulitis involves the deeper dermis and subcutaneous fat; in contrast, erysipelas involves the upper dermis, and there is clear demarcation between involved and uninvolved tissue. A skin abscess is a collection of pus within the dermis or subcutaneous space.
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Treatment for complicated LUTIs:
Treatment: Cefpodoxime, smz/tmp, quinolone.
7-14 day course
Treatment for mild pyelonephritis:
SMZ/TMP or Quinolone
Treat for 14 days
Do NOT use Nitrof________ in pyelonephritis.
Nitrofurantoin
All SSTIs are caused by MSSA and beta-hemolytic streptococci (the GAS).
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Use doxycycline if MRSA is suspected.
“Shade, sunscreen, hydration” regarding tetracyclines.
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Big risk factor for clindamycin is C. diff.
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When purulent drainage, abscess, or ulcer is present, or in cases of penetrating trauma, particularly IV drug use, coverage for MRSA should be initiated. Empirically treat them.
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Hospitalized/severe cellulitis:
Vancomycin (IV) continues to be the drug of choice for severe cellulitis due to MRSA because of its efficacy, afety, and low cost.
Daptomycin (IV), linezolid, or ceftaroline are also acceptable and should be considered over vancomycin when the isolated organism has a MIC of greater than 2 mcg/mL.
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If cellulitis is less severe/outpatient:
For less severe, uncomplicated infections, many CA-MRSA strains can be treated with clindamycin, doxycycline, or TMP/SMZ (Bactrim).
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In less severe/mild/outpatient cellulitis, us B-C-D.
Bactrim
Clindamycin
Doxycycline
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Empiric antimicrobial therapy for cellulitis in previously healthy adults.
Probable etiologic bacteria:
- MSSA
- GAS
- CA-MRSA
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Empiric antimicrobial therapy for cellulitis in immunocompromised, DM, VI, PU, etc:
Probable etiologic bacteria:
- MSSA
- HA-MRSA
- CA-MRSA
- enterobacteriaceae
- P. aeruginosa
- Anaerobes
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Male patient with UTIs are always complicated. Treatment is the same but requires longer duration of treatment.
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