Infectious Diseases II: Chapter 23

what is perioperative antibiotic prophylaxis

bacterial flora at the incision site can cause contamination, IV antibiotics are given prior to surgery to prevent skin flora (staph, strep) and/or gram negative and anaerobic organisms (intrabdominal procedures)

timing of perioperative antibiotics (preoperative, intraoperative, postoperative)

• pre-operative: infuse antibiotic (cefazolin or cefuroxime) within 60 mins before 1st incision. if a quinolone or vanco are used, start the infusion 120 min before 1st incision

• intra-operative: additional doses may be administered for longer surgeries (>4hours) or if there is major blood loss

• post-operative: antibiotics are not usually needed, if used discontinue within 24 hours

what drugs are used perioperative and what do they cover

• cefazolin (1st gen) is preferred for most surgeries to prevent MSSA

• clindamycin if beta lactam allergy

• vancomycin is used if MRSA colonization or risk and if beta lactam allergy

recommended antibiotic for cardiac or vascular surgery and beta lactam allergy alternative

Cefazolin (or cefuroxime), Clindamycin or vanco are b-lactam alternatives

recommended antibiotic for orthopedic(joint replacement) surgery and beta lactam allergy alternative

cefazolin, vanco or clindamycin are b-lactam alternatives

recommended antibiotic for gastrointestinal surgery

• cefazolin + metronidazole, cefotetan, cefoxitin, or unasyn

for meningitis, other than fever, headache, or altered mental status, what is another symptom

nuchal rigidity or stiff neck

how to diagnose meningitis

lumbar puncture to collect cerebrospinal fluid and culture tested, high csf pressure is also indicative

most common bacterial causes of meningitis

neisseria meningitis, streptococcus pneumoniae, and Listeria which is higher in neonates, pts >50, and immunocompromised

how and why is dexamethasone given for community acquired meningitis

given prior to or with first antibiotic dose to prevent neuorological complications

meningitis empiric treatment for neonates (<1month)

• Ampicillin (for listeria) +

• cefotaxime or gentamicin

meningitis empiric treatment for age 1 month to 50 years

Ceftriaxone or cefotaxime + vancomycin

meningitis empiric treatment for >50 years or immunocopromised

ampicillin (for listeria) + ceftriaxone or cefotaxime + vanco

acute otitis media (AOM) signs and symptoms

bulging tympanic (eardrum), otorrhea (middle ear fluid), otalgia (ear pain), tugging or rubbing the ears

common bacteria with AOM

s. pneumoniae, h. influenzae, or moraxella catarrhalis (atypical)

when to consider observation in kids for AOM

• try observation for 2-3 days if symptoms are nonsevere (otalgia <48hrs, no otorrhea, temp <102.2) and:

  • 6-23 months: symptoms in one ear only

  • >2 years: symptoms in one or both ears

• if symptoms do not improve, or worsen, use antibiotics

first line treatment for AOM

• amoxicillin (90 mg/kg/day) or augmentin (90 mg/kg/day - Augentin ES 600 preferred)

• for treatment failure after 2-3 days →ceftriaxone IM

pharyngitis pathogen, symptoms, criteria for treatment, treatment options

• s. pyogenes →strep throat

• sore throat, fever, swollen lymph nodes, white patches on the tonsils

• rapid antigen test

• penicillin or amoxicillin

acute sinusitis pathogen, symptoms, criteria for treatment, treatment options

• s. pneumoniae, h. influenzae, m.catarrhalis (same as AOM)

• nasal congestion, purulent nasal discharge, facial/ear/dental pain, headache

• >10 days of persistent symptoms or .3 days of severe symptoms (temp>102)

• augmentin

acute bronchitis presentation and treatment

cough lasting 1-3 weeks with normal chest x-ray, antibiotics are not recommended

treatment for acute bronchitis caused by bordetella pertussis (whopping cough)

macrolides (azithromycin, clarithromycin)

COPD exacerbations can be caused by which pathogens

h. influenzae, m. catarrhalis, s. pneumoniae

management of acute COPD exacerbation

• supportive treatment

• antibiotics for 5-7 days if any one of the following:

  • all 3 cardinal symptoms (increased dyspnea, increased sputum volume, and increased sputum purulence)

  • increased sputum purulence + 1 additional symptom

  • mechanically ventilated

• preferred antibiotic: augmentin, (azithro, doxy, resp. quinolone)

CAP presentation and pathogens

• SOB, fever, cough, purulent sputum, rales, tachypnea, chest x-ray with infiltrates/opacities/consolidations

• s. pneuomoniae, h. influenzae, m. pneumoniae

assessment for CAP

• assess comorbidites that increase risk of drug resistant s. pneumoniae and require broader coverage

• chornic heart, liver, lung, renal dx, DM, alcohol use disorder, malignancy, asplenia

outpatient CAP tx for healthy patients with no comorbidities

• amoxicillin high dose (1 gram TID) or

• doxycyline (avoid in preg/breast)

• macrolide (azithro or clarithro) if local pneumococcal resistance <25%(prolong QT prolongation)

tx for outpatient CAP for high risk patients with comorbidities

• beta lactam + macrolide or doxy

  • augmentin or cephalosporin (cefpodoxime, cefuroxime)

• respiratory quinolone (moxi or levo)

inpatient CAP treatment for nonsevere/non-ICU

• beta lactam + macrolide or doxy (similar to outpatient high risk)

  • cetriaxone, cefotaxime, unasyn

• respiratory quinolone monotherapy

inpatient CAP tx for severe/ICU

do not use quinolone monotherapy (beta-lactam + macrolide or beta lactam + resp. quin)

inpatient CAP risk factors and tx for pseudomonas and/or MRSA

• MRSA: add vanco or linezolid

• Pseumonas: use zosyn, cefepime, meropenem

• hospitalization and use of parenteral antibiotics in the past 90 days: cover both

when does HAP and VAP occur and what are the common pathogens

• HAP: > 48 hours after hospital admission

• VAP: >48 hours after the start of mechanical ventilation

• nosocomial pathogens, MRSA. MDR gram negative rods including p. aeruoginosa

HAP/VAP: all patients need coverage for pseudomonas and MSSA, examples?

• cefepime

• zosyn

• levofloxacin

HAP/VAP: risk factors for MRSA and examples

• add vanco or linezolid if risk factors: IV antibiotic use in the past 90 days, MRSA prevalence in hospital unitl is >20% or unknown, prior MRSA infectoin or positive MRSA nasal swab

• cefepime + vanco

• meropenem + linezolid

• aztreonam + vanco

HAP/VAP: tx if risk for MDR gram negative pathogens

• use 2 antibiotics for pseudomonas

• risk factors: IV antibiotic use in the past 90 days, prevalence of gram negative resistance in hospital unit is >10%, hospitalized >5days prior to the onset of VAP

• zosyn + cipro + vanco (MRSA usually also present)

• cefepime + gentamicin + linezolid

HAP/VAP: antibiotics for pseudomonas

• beta-lactams: zosyn, cefepime, ceftazidime, imipenem/cilastin, meropenem

• levofloxacin or ciprofloxacin

• aztreonam

• aminoglycosides (typically tobramycin)

what is tuberculosis caused by

mycobacterium tuberculosis

how is latent tb diagnosed

• tuberculin skin test (TST) also called PPD - intradermal solution which is inspected for induration (a raised area) 48-72 hours later

• an interferon gamma release assay (IGRA) - preferred for those who received BCG vaccine which can provide a false positive TST

difference between latent tb infection and active tb infection

• latent: no symptoms, not contagious, treat with 1or 2 drugs for 3-4 months, negative chest x-ray

• active: highly contagious, hemoptysis, positive x-ray(infiltrates), RIPE treatment

who is tested for latent TB

• close contact with someone who is active

• high risk condition (HIV, tansplant, lymphoma)

• treatment with TNF alpha inhibitors

criteria for positive TB skin test

• if someone has HIV or immunosuppression: >5mm induration is positive

• if someone is in high risk congregate settings (prisons, healcare facilities, homeless shelters): >10mm

• pts with no risk factors: >15mm

treatment regimens for latent tb

• INH + rifapentinn weekly for 12 weeks via directly observed therapy (DOT) - do not use in pregnant

• INH + rifampin daily for 3 months

• rifampin daily for 4 months

• INH daily for 6-9 months - for HIV pts, take with vitamin b6 to avoid peripheral neuropathy

• shorter regimens are preferred due to higher completion rates and less risk of hepatotoxicity

active tb diagnosis

• cough/hemoptysis, fever, night sweats

• m. tuberculosis is an acid fast bacilli (AFB → AFB smear is done but not definitive

• sputum culture results - MTB is slow-growing and results take up to 6 weeks

• chest x-ray with consolidates

active tb treatment

• intensive phase: rifampin, isoniazid, pyrazinamide, ethambutol (RIPE) for 2 months

• continuation phase: rifampin and isoniazid for 4 months

rifampin side effects

increased LFTs, hemolytic anemia (Coombs), flu-like syndrome, orange-red discoloration

rifampin contraindications and interactions

• do not use with protease inhibitors

• rifabutin can replace rifampin (if taking PI →HIV pts)

• potent inducer of CYP and pgp: PI, warfarin, DOACS, OC

INH boxed warning/warnings/SE

• BOXED: hepatitis

• warning: peripheral neuropathy →take pyridoxine (B6) 25-50 mg

• SE: increased LFTs, DILE, hemolytic anemia

pyrazinamide contraindications and SE

• contrain: acute gout

• SE: increased LFTs, hyperuricemia/gout

ethambutol SE

increased LFTs, optic neuritis, confusion, hallucinations

what is infective endocarditis

infection of heart valves

pathogens of infective endocarditis

staphlococci, streptococci, enterococci

diagnosis of IE

echocardiogram and positive blood cultures

treatment of IE

Iv antibiotic treatment if required. gentamicin is used for synergy and target peak levels of 3-4mcg/ml and trough levels <1 mcg/ml

patients at risk for IE and qualify for dental prophylaxis

dental work needed, such as root canal + select cardiac conditions involving heart valves

adult IE dental prophylaxis

single dose 30-60 minutes before

• first line: amoxicillin 2 g PO

• if allergic to pcn: Azithromycin or clarithromycin 500 mg or Doxycyline 100 mg

what is spontaneous bacterial peritonitis and how does it present

infection of peritoneal space that occurs in pts with cirrhosis and ascites. fluid sample, paracentesis, reveals >250 cells/mm3 PMNs (polynuclear leukocytes)

treatment for spontaneous bacterial peritonitis

empiric tx with ceftriaxone for 5-7 days and second prophylaxis with bactrim or cipro

what should generally be covered for intraabdominal infections

usually polymicrobial, stretococci, enteric gram negatives, anaerobes (b. fragilis) - empiric coverage, if no anaerobic coverrage, usually metronidazole is added

types of sstis

• superficial: impetigo, furuncle, carbuncle

• subcutaneous tissues: cellulitis

• they can nonpurulent or purulent like an abscess

mild, moderate, severe infections SSTIs classifications

• mild: no systemic signs

• moderate: systemic signs (temp>100.4, HR>90, WBC>12,000 or <4,000)

• severe: systemic signs, signs ofdeeper infection, pt is immunocomp or failed oral antibiotics + incision and drainage

impetigo presentation and tx

• honey-colored crusts due to blister like rash rupturing

• topical antibiotic - mupirocin

• numerous, extensive lesions - cephalexin

folliculitis/furuncle/carbuncle pathogen and tx

• folliculitis; superficial inflammation of hair follicles

• furuncle (boil): purulent infection of hair follicle

• carbuncle: group of infected furuncles

• CA-MRSA

• bactrim or doxycycline to cover MSSA and MRSA

cellulitis tx

cephalexin to cover strep and MSSA

Abscess pathogens and tx

• CA-MRSA

• bactrim or doxycycline to cover MSSA and MRSA

tx for severe purulent SSTI

• cover MRSA

• vanco

• daptomycin

• linezolid

necrotizing fascilitis

vanco or daptomycin + beta-lactam (zosyn, meropenem) + clindamycin (to suppressstrep toxin production)

how to diagnose UTI

urinalysis which is determined positive when there is evidence of pyuria(WBC), bacteria, and positive leukocyte esterase and/or nitrites - positive urinalysis is followed by urine culture

UTI symptoms

• cystitis (Lower UTI)

  • urgency and frequency, nocturia

  • dysuria (painful)

  • suprapubic tenderness

  • hematuria

• pyelonephritis (upper UTI)

  • flank pain

tx and pathogen for acute cystitis

• e.coli

• nitrofurantoin (Macrobid) 100 mg PO BID x 5 days (contraindicated if CrCl <60ml/min)

• bactrim DS 1 tablet PO BID x 3 days (do not use if sulfa allergy)

• fosfomycin x 1 dose

• alternative: pregnancy → amoxicillin or cephalexin

acute pyelonephritis moderately ill outpatient (PO) tx

based on local quinolone resistance being > or < 10%

acute pyelonephritis severely ill hospitalized patient (IV) tx

• ceftriaxone or cipro or levo

• concern for resistance: zosyn or carbapenem (if ESBL-producing suspected)

what is phenazopyridine and dose and SE

• urinary analgesic

• Pyridium, Azo Urinary Pain Relief

• 2 days max

• take with 8 oz of water with food to minimize stomach upset

• may cause red-orange coloring of the urine and other bodily fluids

bacteriuria and pregnancy tx

• must be treated even if asymptomatic

• amoxicillin + clav or and oral cephalosporin

• quinolones should be avoided

what are the treatment options if 1st episode of C diff

• fidaxomicin (FDX/Dificid) 200 mg PO BID x 10 days OR

• vanco 125 mg PO QID x 10 days (standard regimen)

• metronidazole (MET) 500 mg PO TID x 10 days (non severe, above is unavailable)

tx for 2nd episode (1st recurrence) c.diff

• FDX(Dificid) 200 mg PO BID x 10 days (same as 1st episode)

• vanco standard regimen followed by a prolonged pule/tapered course (without prolonged taper if MET was used for initial episode)

• tapered and pulsed regimen = 125 mg PO QID x 10 days, BID x 1 week, daily x 1 week, then 125 mg every 2-3 days for 2-8 weeks

tx for 3rd or subsequent episodes of c.diff

• FDX(Dificid) 200 mg PO BID x 10 days (same as others)

• Vanco standard regimen followed by a prolonged pule/tapered course OR

• vanco standard regimen followed by rifaximin 400 mg TID x 20 days OR

• fecal microbiota transplantation

• tapered and pulsed regimen = 125 mg PO QID x 10 days, BID x 1 week, daily x 1 week, then 125 mg every 2-3 days for 2-8 weeks

tx for fulminant/complocated c. diff

• diagnosed when significant systemic toxic effects are present such as hypotension, shock, ileus or toxic megacolon, can occur with any episode/recurrence

• vanco 500 mg/PO/NG/PR QID + MET 500 mg IV q8h

when is adjunct bezlotoxumab used for c.diff

for high risk pts: > 65 years, immunocomp, severe presentation and/or experiencing a 2nd episode of CDI within the past 6 months to reduce the risk of recurrence ONLY

s+s/risk factors for CDI

• three, watery stools per day, abdominal cramps, fever, elevated WBC

• healthcare exposure, PPIs, advanced age, immunocompromised, previous CDI

symptoms of common STIs: chlamydia, gonorrhea, genital warts, latent syphilis, primary syphilis, bacterial vaginosis, trichomoniasis

• chlamydia: genital discharge and no symptoms

• gonorrhea: genital discharge and no symptoms

• genital warts: single or multiple pink/skin-toned lesions

• latent syphilis: asymptomatic

• primary syphilis: ainless, smooth genital sores (chancre)

• bacterial vaginosis: vaginal discharge (clear,white,gray) that has fishy odor and ph>4.5, little or no pain

• trichomoniasis; yellow/green, frothy vaginal discharge with ph>4.5, soreness, pain with intercourse

primary(chancre), secondary(rash), or early latent(asymptomatic, within past year) syphilis diagnosis and tx

• diagnosis: RPR or VDRL , painless chancres

• tx: Bicillin-LA (Penicillin G) 2.4 million units IM x 1

• if b-lactam allergy: doxy x 14 days, if pregnant desensitize and treat with Bicillin-LA

tx for late latent(>1year ago) or teritiary syphilis

• Bicillin-LA 2.4 million units IM weekly x 3 weeks

• b-lactam allergy: doxy

tx for neurosyphilis

• penicillin G aqueous IV

Penicillin desensitization for syphilis

• a pregnant woman cannot take alternative tx doxycycline due to fetal defects (suppressed bone growth and skeletal development)

• a patient with poor compliance is at risk for tx failure with doxy which needs to be taken twice daily for 14 days

• confirm allergic reaction with skin test, temporarily desensitize the pt per protocol, tx with Bicillin-LA IM

tx for gonorrhea

• ceftriaxone: <150kg: 500 mg IM x 1 (x2 for >150kg)

• if chlamydia not excluded: add doxy

tx for chlamydia

• non-pregnant: doxycycline 100 mg PO BID x 7 days

• pregnant: azithromycin 1 gram PO x 1

tx for bacteiral vaginosis

• metronidazole or metronidazole 0.75% gel

tx for trichomoniasis

metronidazole, can be used for all trimesters of pregnancy

tx for gential warts

• HPV

• gardasil vaccine reduces risk of warts, cervical cancers, other cancers

• imiquimod cream

most common tickborne disease

rocky mountain spotted fever is most common and most fatal in US, erythematous petechial rash 3-5 days after symptoms

tx for tickborne diseases: rockymountain spotted fever, lyme disease, ehrlichiosis

• doxycycline (even in pediatric)

difference between ringworm and lyme disease

• lyme: bacterial infection (Borrelia burgdorferi and borrelia mayonnii) spread by ticks, ertyhema migrans or bull's eye rash, achy joints, fever, diagnosed by EIA, treated with doxy

• ringworm: fungal infection (tinea corporis), raised rings, itchy, treated with clotrimazole or other antifungal