Exam 3 Flashcards
What physiologic mechanisms do the lungs have to normally resist infection and impair host defense mechanisms?
Upper Airways:
- Nasopharynx: nasal hair, turbinates; anatomy of upper airways; mucociliary apparatus; IgA secretion
- Oropharynx: saliva; sloughing of epithelial cells; complement production
Conducting Airways:
- Trachea, bronchi: cough, epiglottic reflexes; sharp, angled, branching airways; mucociliary apparatus; immunoglobulin production (IgG, IgM, IgA)
Lower Respiratory Tract:
- Terminal airways, alveoli: alveolar lining fluid (surfactant, fibronectin, complement, immunoglobulin); cytokines (TNF, IL-1, IL-8); alveolar macrophages (produce cytokines and recruit neutrophils, so the area becomes acidic and hypoxic); PNMs; cell-mediated immunity
What etiologic organisms are commonly encountered in community-acquired pneumonia, hospital-acquired pneumonia, and ventilator-associated pneumonia?
CAP: pneumonia developed outside of the hospital or <48h after hospital admission. Bacterial pneumonia is most commonly caused by aspiration.
- Viral cause most common
1. Streptococcus pneumoniae
- Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, Chlamydia pneumoniae
HAP & VAP: pneumonia occurring ≥ 48h after hospital admission; pneumonia occurring > 48-72h after endotracheal intubation
- aerobic gram-neg bacilli: P. aeruginosa, enteric gram-neg bacilli, Acinetobacter baumannii
- S. aureus (MRSA)
What etiologic organisms are commonly encountered in acute bacterial exacerbations of chronic bronchitis?
H. influenzae - 45%
S. pneumoniae - 20%
M. catarrhalis - 30%
- Enterobacterales, P. aeruginosa - seen in end-stage COPD
What is the common microbial etiology of pharyngitis?
Viruses are most common.
Streptococcus pyogenes are the most common bacterial pathogen.
What is the common microbial etiology of acute bacterial rhinosinusitis?
Haemophilus influenzae
Streptococcus pneumoniae
Moraxella catarrhalis
What is the clinical presentation of a pt with CAP, HAP, and VAP?
CAP: Usually a sudden onset of fever, chills, pleuritic chest pain, dyspnea, productive cough (but more gradual and lower severity with Mycoplasma pneumoniae and C. pneumoniae), tachycardia, tachypnea (& cyanosis, nasal flaring), consolidation
- In elderly: classic symptoms may be absent; may be decline in functional status, weakness, mental status, anorexia, abdominal pain
- Radiography: dense lobar consolidation
What is the clinical presentation of a pt with acute bronchitis, acute bacterial exacerbations of chronic bronchitis, pharyngitis, and sinusitis?
Acute bronchitis - cough, coryza, sore throat, malaise, headache, fever, normal chest x-ray
Acute bacterial exacerbations of chronic bronchitis - chronic cough productive of sputum on most days for at least 3 consecutive months each year for two years. 3 cardinal symptoms include increased cough/dyspnea (SOB), increased sputum volume, and increased sputum purulence
Pharyngitis - Sudden onset of sore throat with dysphagia, fever, pharyngeal hyperemia and tonsillar swelling, enlarged, tender lymph nodes, red, swollen uvula.
*cannot differentiate between bacterial and viral etiology, unless overt viral features are present
Sinusitis - Up to 4 weeks of purulent nasal drainage accompanied by nasal obstruction, facial pain-pressure-fullness, or both;
What determines the diagnosis of ABRS (acute bacterial rhinosinusitis)?
- Onset of persistent symptoms or signs compatible with acute rhinosinusitis, lasting for ≥10 days without any evidence of clinical improvement
- Onset with severe symptoms or signs of high fever (≥ 39ºC) and purulent nasal discharge or facial pain lasting for at least 3-4 consecutive days at the beginning of the illness
- Onset with worsening symptoms or signs characterized by the new onset of fever, headache, or increase in nasal discharge following a typical viral URTI that lasted 5-6 days and was initially improving (“double sickening”)
What are appropriate examinations and diagnostic/lab tests to assist in the diagnosis of respiratory tract infections?
- PCR (for respiratory viruses)
- NPV
- chest X-ray
- WBC w/ differential
- serum creatinine
- BUN
- electrolytes
- LFTs (more likely altered in legionella)
- procalcitonin
- O2 sat
- urinary antigen tests (not routinely used)
- sputum exam (in hospital)
- cultures
- blood cultures (if suspected HAP or VAP)
What risk factors are associated with infections caused by multidrug-resistant Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa in CAP and MDR organisms in HAP/VAP?
MDR Streptococcus pneumoniae - antibiotic use w/in prev. 3 months, over 65 years old, DM, chronic lung disease/asthma, CAD/CHF, dialysis, HIV, alcohol abuse, cirrhosis, malignancy, use of an immunosuppressive medication
MDR MRSA - concurrent/recent influenza infection, hx of skin infection with CA-MRSA, necrotizing pneumonia or cavitary infiltrates, rapid progression of symptoms, respiratory failure, ICU admission, formation of empyema
MDR Pseudomonas aeruginosa - ??
MDR organisms in HAP/VAP - Prior IV antibiotics within 90 days, at least 5 days of hospitalization prior to occurrence of VAP, septic shock at time of VAP, ARDS before VAP, acute renal replacement therapy prior to VAP
What is the appropriate empiric antimicrobial therapy for the treatment of outpatient CAP (in pts w/ or w/o risk factors for resistant bacteria)?
- Hypoxemic -> Humidified oxygen, bronchospasm -> bronchodilators (albuterol), fluids, chest physiotherapy if needed
- Duration of treatment should be 5 days minimum, based on clinical stability
Healthy outpatient adults w/o comorbidities:
- amoxicillin 1g PO q8h (preferred)
- doxycycline 100mg PO q12h
- macrolide (if resistance is <25%, but likely won’t be used as monotherapy): azithromycin 500mg PO day 1, then 250mg for 4 days; clarithromycin 500mg PO q12h or 1000mg ER daily
Outpatients with comorbidities: (ex. chronic heart, lung, or renal disease, diabetes mellitus, alcoholism, malignancy, asplenia or immunosuppressive condition/drugs)
- Respiratory fluoroquinolone: levofloxacin 750mg daily, moxifloxacin 400mg daily
- combo therapy: β-lactam + macrolide OR β-lactam + doxycycline
- β-lactams: amox/clav, cefpodoxime, cefuroxime
- macrolide
- doxycycline
What is the appropriate empiric antimicrobial therapy for the treatment of inpatient CAP (inpatient non-severe, inpatient severe, inpatient + MRSA or P. aeruginosa concern)?
Inpatient non-severe: no risk factors for MRSA or P. aeruginosa
- β-lactam + macrolide OR β-lactam + doxycycline: amp/sul; ceftriaxone 1-2g IV q24h; azithro/clarithromycin
- respiratory fluoroquinolone monotherapy
- If contraindicated to FQs and macrolides: β-lactam + doxycycline 100mg IV/PO q12h
Inpatient severe: no risk factors for MRSA or P. aeruginosa
- β-lactam + macrolide (preferred)
- β-lactam + respiratory fluoroquinolone
Inpatient + concern for MRSA and/or P. aeruginosa
- MRSA: add vanc or linezolid
- P. aeruginosa: add coverage with pip/tazo, cefepime, ceftazidime, aztreonam, meropenem, imipenem (no ertapenem or daptomycin)
What is the appropriate directed antimicrobial therapy for the treatment of CAP (in pts w/ or w/o risk factors for resistant bacteria) when the organism(s) is (are) known? (S. pneumoniae, H. influenzae, mycoplasma pneumoniae/Chlamydia pneumoniae, legionella pneumophila, staphylococcus aureus, anaerobes, and enterobacterales)
Streptococcus pneumoniae:
- pen-susceptible: pen G or amoxicillin
- pen-resistant: respiratory FQ, ceftriaxone, cefotaxime
H. influenzae:
- non β-lactamase producing: ampicillin IV, amoxicillin
- β-lactamase producing: 2nd or 3rd gen cephalosporin, amp/sulbactam, amox/clav
Mycoplasma pneumoniae or Chlamydia pneumoniae:
- macrolide, doxycyline
Legionella pneumophila:
- fluoroquinolone, azithromycin
Staphylococcus aureus:
- methicillin-susceptible: nafcillin, cefazolin
- methicillin-resistant: vancomycin, linezolid
Anaerobes: β-lactam/β-lactamase inhibitor, clindamycin
Enterobacterales: 3rd or 4th gen cephalosporin, carbapenem
What is the appropriate empiric antimicrobial therapy for the treatment of HAP? (low risk, MRSA, high-risk)
Not at high risk of mortality & no increasing likelihood of MRSA -> provide coverage for MSSA
- pip/tazo, cefepime, imipenem OR meropenem
Not at high risk of mortality but factors for MRSA:
- pip/tazo, cefepime, ceftaidime, imipenem, meropenem, levofloxacin, ciprofloxacin, OR aztreonam
- PLUS vanc OR linezolid
High risk of mortality or prior IV antibiotic use during prior 90 days:
- Two of the following: [pip/tazo, cefepime, ceftazidime, imipenem, meropenem], [levofloxacin OR ciprofloxacin], [aminoglycoside, OR aztreonam]
- PLUS vanc OR linezolid
What is the appropriate empiric antimicrobial therapy for the treatment of VAP?
All empiric regimens should cover S. aureus, P. aeruginosa, and other gram-negative bacilli (Enterobacterales)
β-lactams w/ antipseudomonal activity: pip/tazo, cefepime, ceftazidime, imipenem, meropenem, aztreonam
non-β-lactams w/ antipseudomonal activity: ciprofloxacin, levofloxacin, amikacin, gentamicin, tobramycin, colistin, polymyxin B
Include an agent against MRSA (vanc or linezolid) if:
- risk factors for MRSA
- pts treated in ICUs where 10-20% of S. aureus isolates are methicillin-resistant
- pts treated in ICUs where prevalence of MRSA is unknown
If empirically covering MSSA: pip/tazo, cefepime, imipenem, meropenem (cefazolin, nafcillin, or oxacillin if directed therapy for MSSA)
Prescribe 2 antipseudomonal antibiotics from different classes ONLY if:
- risk factors for antimicrobial resistance
- patients in ICU where over 10% of gram-neg isolates are resistant to monotherapy agent
- pts in ICUs where local resistance rates are unknown
What is the appropriate directed antimicrobial therapy for the treatment of HAP and VAP when the organism(s) is (are) known? (MSSA, MRSA, Enterobacterales, ESBL producer, MBL producer, KPC producer, P. aeruginosa monotherapy, Acinetobacter baumannii, MDR to all other options)
MSSA - cefazolin, nafcillin, oxacillin
MRSA - vanc or lineolid
Enterobacterales - lots of options
ESBL producer - carbapenem (DOC), ceftazidime/avibactam
MBL producer - aztreonam + ceftazidime/avibactam empirically; aztreonam monotherapy if susceptible; cefiderocol
KPC producer - ceftazidime/avibactam, meropenem/vaborbactam, imipenem/cilastatin/relebactam, cefiderocol
Pseudomonas aeruginosa - monotherapy; if pt in septic shock for high risk of death -> combo therapy to which isolate is susceptible; if MDR -> ceftolazane/tazo, ceftazidime/avi, imipenem/cilastatin/relebactam, cefiderocol
Acinetobacter baumannii - carbapenem or ampicillin/sulbactam if susceptible; if resistant to carbapenem or sulbactam -> cefiderocol, sulbactam/durlobactam
MDR to all other options -> Polymyxin B
Treatment should be 7 days
What is the appropriate empiric antimicrobial therapy for the treatment of acute bronchitis?
NO ANTIBACTERIAL THERAPY WARRANTED
Treatment should only be symptomatic (ex. antitussives, antipyretics, adequate hydration). Avoid corticosteroids
What are the risk factors we need to assess with acute exacerbations of chronic bronchitis? (7)
Age 65
COPD severity
>4 exacerbations/year
Cardiac disease
Home oxygen use
Antibiotic use in last 3 months
Recent corticosteroid use
What is the appropriate empiric antimicrobial therapy for the treatment of acute exacerbations of chronic bronchitis when the organism(s) is (are) known? (uncomplicated, complicated, complicated w/ pseudomonas risk) + duration
Treatment should be 5-7 days with the goal of prompt resolution of symptoms and positively influence the duration of patient’s symptom free post-treatment period.
Uncomplicated - <65 years old, FEV > 50%, < 4 exacerbations/year, no comorbidities, no risk factors
- azithryomycin, clarithromycin
- 2nd/3rd gen cephalosporin
- doxycycline
- amoxicillin
- TMP/SMX
Complicated - ≥ 2 risk factors
- Respiratory fluoroquinolone
- Amox/clav
Complicated + Pseudomonas - severe symptoms, constant, purulent sputum, FEV <35%
- ciprofloxacin or levofloxacin
- piperacillin/tazobactam
- IV coverage if hospitalized
What is the appropriate empiric antimicrobial therapy for the treatment of pharyngitis or sinusitis?
Pharyngitis - symptomatic care
- Group A strep: penicillin V is the drug of choice!, amoxicillin is #2, can use 2nd gen cephalosporins as an option if penicillin or amoxicillin fails; 10 day course
- Group A strep + pen-allergic: 1st gen cephalosporin if no anaphylaxis; macrolide (azith/clarith), clinda; 5 day course
Sinusitis - symptomatic care
1. Amox/clav
- if β-lactam allergy: doxycyline, levofloxacin, moxifloxacin
- if risk for antibiotic resistance or failed initial therapy: amox/clav higher dose, levofloxacin, moxifloxacin
- if severe infection requiring hospitalization: amp/sulbactam, levofloxacin, moxifloxacin, ceftriaxone
- macrolides only in pen-allergic pts due to high prevalence of resistance in S. pneumoniae
- TMP/SMX has high resistance rates in S. pneumoniae
What is the pathogenesis, risk factors, bacterial etiology, and symptoms of impetigo?
Pathogenesis - (1) organism can directly invade healthy skin, (2) organism introduced into superficial layers of the skin during trauma or abrasions
Risk factors - Children, skin trauma, hot/humid climates, poor hygiene, day care settings, crowding, malnutrition, diabetes
Bacterial etiology - Most cases caused by Staphylococcus aureus and/or Streptococcus pyogenes (Group A strep)
Symptoms - Maculopapular lesions that rupture, leaving superficial erosions that are occasionally pruritic or painful with honey-colored crust. Can be non-bullous or bullous
What is the pathogenesis, risk factors, bacterial etiology, and symptoms of cellulitis?
Pathogenesis - Organism is introduced to the skin during trauma, woulds, Athlete’s feet, dry, crackled skin, injection drug use, ulcers, or surgery
Risk factors - Diabetes, IV drug use, arterial or venous insufficiency, obesity, lymphedema, immunocompromised
Bacteriology - Depends on patient age and/or risk factor. In infants an children -> H. flu, S. pyogenes, S. agalactiae (neonates); Staph is a common one; If the infection has an abscess, it’s due to CA-MRSA
Symptoms - Rapidly spreading area of redness, tenderness, warmth, and swelling in the skin with a POORLY defined border. May also see fever, malaise, regional lymphadenopathy, lymphangitis, leukocytosis, especially with a deeper infection.
What is the pathogenesis, bacterial etiology, and symptoms of necrotizing fasciitis?
Pathogenesis - Same as cellulitis, but it’s caused by a toxin-producing organism that progressively destroys superficial fascia and subcutaneous fat
Bacteriology - If monomicrobial -> group A strep (S. pyogenes), S. aureus (probs CA-MRSA); if polymicrobial -> mix of aerobes and anaerobes from the GI or GU tract
Symptoms - Cellulitis and intense pain, bullae, crepitus, wooden-hard induration, cutaneous gangrene and systemic toxicity (fever, MS changes, hypotension)
What is the pathogenesis, risk factors, bacterial etiology, and symptoms of diabetic foot infection?
Pathogenesis - Caused by the presence of neuropathy, angiopathy with ischemia, dry skin, decreased wound healing, and immune defects associated with DM. Or, the patient develops an ulcer or sustains an injury, they are unaware of it due to neuropathy, the bacteria invades the would and illicits a host response.
Risk factors -
- MRSA: hx of MRSA in past year, prevalence of MRSA over 30-50% in local area, recent hospitalization or antibiotic use in last 30 days, etc.
- Pseudomonas: soaking feet, failed non-pseudomonal antibiotics, macerated ulcer, warm climate
Bacteriology - MRSA, pseudomonas, staph, strep,
How are diabetic foot infections classified?
DFI: ulcer with at least 2 signs of inflammation (local swelling/induration, local tenderness/pain, erythema, local increased warmth, purulent drainage)
Mild: Erythema over 0.5cm but less than 2cm around the wound. No systemic manifestations or bone involvement
Moderate: Erythema over 2cm around the would. Involvement of skin structures deeper than subcutaneous. No systemic manifestations. Potentially bone invovlement
Severe: Erythema of any size. SIRS positive, which is two of the following: temp over 38ºC or under 36ºC, HR over 90 bpm, RR over 20bpm, WBC over 12K or under 4k or over 10% bands. Potential bone involvement.
What are the methods used for the diagnosis of impetigo, cellulitis, necrotizing faciitis, and diabetic foot infection?
Impetigo - based on clinical presentation (honey-colored, crusty discharge on legion with an erythematous base)
Cellulitis - based on clinical presentation (poorly defined border), increased white count
Necrotizing fasciitis - based on clinical presentation, increased white count, culture of deep tissue/blood cultures, radiography
Diabetic foot infection - Physical exam, labs, cultures, radiography, Ankle Brachial Index (ABI)
What are the principles of treatment of impetigo, cellulitis, necrotizing fasciitis, and diabetic foot infection?
Impetigo - Topical for mild cases (5 days), PO antibiotics for pts with numerous lesions or outbreaks affecting several people to help decrease transmission (7 days)
Cellulitis - Prompt therapy is neccessary. Choice of antibiotic is based on the most probable organism, patient characteristics, severity of infections, etc. If purulent -> treat BOTH Staphylococcus aureus and group strep. If non-purulent -> group strep and MSSA;
Necrotizing fasciitis - primary treatment is surgery (repeat w/ drainage until infected/necrotic tissue is no longer present), also combination of broad spectrum IV antibiotics until no more surgery is needed and/or the source is found
Diabetic foot infection - Therapy usually 1-2 weeks, may be extended to 3-4 weeks if responding slower than expected, improving but extensive infection, or severe peripheral artery disease. If bone is involved, therapy is 6 weeks.
- DFI - also need wound care, cultures, glycemic control, activity restriction, and smoking cessation
What is the empiric and directed treatment regimen for a patient with skin and soft tissue infection? (impetigo, cellulitis, nec fasc)
Impetigo - cephalexin 250-500mg PO QID in adults; 25-50mg/kg/day PO in 3-4 in divided doses for children; duration is 7 days with antibiotics)
Cellulitis - If Mild/Mod infection, used PO, if mod-severe, use IV
- Empiric: mild/mod -> dicloxacillin OR cephalexin (CA-MRSA -> TMP-SMX OR clindamycin OR linezolid); mod/severe -> nafcillin OR cefazolin (CA-MRSA) -> vancomycin OR linezolid
- Directed: narrow treatment to the organism (s. pyogenes -> penicillin, G(-) -> 3rd gen cephalosporin, extended-spectrum penicillin); duration is 5-7 days
Nec fasc -
- Empiric: vanc (MRSA), pip/tazo OR meropenem (GNR + aerobes), AND clinda (suppresses toxin production); could also take off vanc and clinda and use linezolid instead, but $$$
How do you treat a mild DFI? (normal, b-lactam allergy, recent antibiotic exposure, MRSA risk factors)
Mild is usually treated with PO antibiotics (1-2 weeks)
normal: usual pathogen is staph or strep
- cephalexin, dicloxacillin, amox/clav
b-lactam allergy: usual pathogen is staph or strep
- clindamycin, TMP/SMX, doxycycline
recent antibiotic exposure in last 30 days: same GPCs + GNR
- amox/clav, TMP/SMX
MRSA risk factors: MRSA
- TMP/SMX, clindamycin, doxycycline, linezolid
How do you treat a moderate DFI? (normal, recent antibiotics, macerated ulcer or warm climate, MRSA risk factors, ischemic limb/necrosis/gas forming)
3-4 weeks
normal: b-hemolytic strep and/or staph
- IV amp/sulbactam, cefazolin
recent antibiotics: enterobacterales
- ceftriaxone alone
macerated ulcer or warm climate: GNR including pseudomonas
- IV pip/tazo, carbapenem (meropenem/imipenem)
MRSA risk factors: MRSA
- add IV vancomycin, daptomycin, or linezolid
Ischemic limb/necrosis/gas forming: GPC + GNR + strict anaerobes
- pip/tazo, carbapenems OR ceftriaxone/cefepime + metronidazole
How do you treat a severe DFI?
Usually treated with IV therapy then transitioned to PO. 3-4 weeks unless osteomyelitis (3-6 weeks)
Usual pathogens: b-hemolytic strep and staph (MSSA, MRSA), enterobacterales, pseudomonas, anaerobes
- vanc AND pip/tazo, meropenem, ceftazidime/cefepime with IV metronidazole
What are the monitoring parameters for a patient with skin and soft tissue infection?
s/sx of infection - daily during initiation of therapy, then weekly
culture/sensitivity - at initiation of treatment, not usually done for impetigo or cellulitis
WBC count - initially, then 1-2x/week until normal
ESR or C-reactive protein - initially, then weekly during therapy
adverse effects - daily, weekly lab monitoring
radiography - initially, then as needed to document resolution
What is asymptomatic bacteriuria (ASB) and when is it recommended to treat?
ASB - presence of bacteria in the urine but without symptoms
Not recommended to treat unless:
1. Pregnant
2. Undergoing invasive urologic procedure causing tissue/mucosal damage
3. Recent renal transplant (within 1-3 months)
What are characteristics of patients with complicated UTIs? (10)
- Function or anatomical abnormality of the urinary tract
- Indwelling urinary catheter
- Recent urinary tract instrumentation
- History of childhood UTI
- Recent antimicrobial use
- Symptoms for >7 days at time of presentation
- Pregnant women
- Men
- Elderly
- Diabetes or other immunosuppression
What are the most common pathogens in acute uncomplicated cystitis, acute uncomplicated pyelonephritis, complicated UTI, and catheter-associated UTI?
acute uncomplicated cystitis - E. coli
acute uncomplicated pyelonephritis - E. coli
complicated UTI - E. coli, Enterococci, Pseudomonas
catheter-associated UTI - E. Coli, Yeast
What are we concerned about with bacteriuria if we don’t treat? (normal, kidney transplant, pregnancy)
- Symptomatic UTI
- Frequent recurrence
- Pyelonephritis
- Kidney injury
- Urosepsis
For kidney transplantation:
- loss of graft function
- acute graft rejection
For pregnancy:
- preterm birth
- low birth weight
How do we diagnose UTIs? (what lab values are we looking for)
Signs of infections: SYMPTOMS
- Urinalysis: bacteria >10^5 CFU (or less with foley), WBC >10k, Leukocyte Esterase present, Nitrate test (not definitive)
How do patients with cystitis vs. pyelonephritis present?
Cystitis -
- symptoms generally abrupt
- NEW dysuria, urgency, frequency
- Nocturia
- Suprapubic heaviness, lower back pain
Pyelonephritis -
- Flank pain
- Systemic symptoms
What is the presentation of complicated UTIs, especially for elderly pts and indwelling catheters/neurologic disorders?
- May be atypical and non-specific
Elderly:
- AMS
- Malaise
- Change in appetite
- Urinary incontinence
Indwelling catheters or neurologic disorders:
- Lower tract symptoms may be absent
- Flank pain and fever more common
How do we diagnose cystitis or pyelonephritis?
Microbiologic criteria:
- > 100,000 CFU
- If catheter: > 1,000 CFU
PLUS:
- Cystitis symptoms: dysuria, frequency, urgency, suprapubic pain
- Pyelonephritis symptoms: fever, CVA tenderness, rigors, altered mental status, malaise
What are the risk factors and symptoms for prostatitis?
Risk factors: urethral instrumentation, prostatic surgery, receptive anal intercourse, may have no risk factors
Symptoms:
- Acute: fever, chills, malaise, myalgia, dysuria, cloudy urine, swollen/tender prostate
- Chronic: dysuria, frequency, urgency, perineal discomfort, pelvic/back pain, recurrent UTIs, normal prostate
What is the pathophysiology of prostatitis?
Natural defense mechanisms: Prostate produces antibacterial substances & mechanism flushing of urethra by voiding and ejaculation
Poor drainage of secretions from peripheral ducts or urine into prostatic tissue can lead to inflammation, fibrosis, or stones.
Prostatitis most commonly follows a UTI (infected urine ascending the urethra into the intraprostatic ducts)
What are the common pathogens of prostatitis in men?
Gram(-): Enterobacteriaceae (E. coli, Proteus), Pseudomonas aeruginosa
Gram(+): Entercoccus spp., S. aureus
Others (less likely):
- Acute: N. gonorrhea, Chlamydia
- Chronic: fungi
What are the 1st line treatments per the IDSA guidelines for GU infections?
Nitrofurantoin
TMP/SMX
Fosfomycin
What is the spectrum of nitrofurantoin?
Gram(+):
- Enterococcus (faecalis and faecium)
Gram(-):
- E. coli
- Citrobacter
- Salmonella
- Shigella
- Enterobacter
- K. pneumoniae
DOES NOT CONCENTRATE ANYWHERE BUT THE BLADDER!!
When should we NOT use nitrofurantoin?
If infection is not in the bladder
When CrCL is less than 30mL/min
- adequate urinary concentrations not achieved
- increased risk of systemic toxicities
Can we use nitrofurantoin in elderly or pregnant patients?
Elderly: generally avoid in pts over 60 years old
Pregnancy: widely used in pregnancy, but use cautious in mothers with G6PD
What is the spectrum of activity for TMP/SMX?
Gram(+):
- Staphylococcus (MRSA, MRSE)
- Listeria monocytogenes
Gram(-):
- Enterobacteriaceae: E. coli, K. pneumonia, Enterobacter, etc.
What is the SMX/TMP dosing in most UTI patients?
1 DS (800mg SMX, 160mg TMP), tab BID
Dose based off of TMP
*needs renal dose adjustments
What are important adverse effects for SMX/TMP?
GI: nausea, abdominal pain
Rash: erythematous, maculopapular, +/- pruritis
Renal: increase in serum creatinine, interstitial nephritis, hyperkalemia, hyponatremia
What are some precautions with SMX/TMP?
Pregnancy category C due to impaired folate utilization in 1st trimester and kernicterus in 3rd trimester. Consider risk/benefit, don’t tend to use.
Drug interactions: CYP450 2C9 inhibitor/substrate, caution with warfarin
What is the MOA and spectrum of fosfomycin?
MOA: inhibits bacterial cell wall synthesis
- prodrug, one time dose
- long half life
Spectrum:
- E. coli
- Enterococcus spp.
- Useful for resistant organisms
