Infectious Diseases Review for the Family Medicine Boards July 2010

Transcription

1 Infectious Diseases Review for the Family Medicine Boards July 2010 Disclosure Pfizer: Investigator initiated research grant Brian Schwartz, MD Assistant Clinical Professor UCSF, Division of Infectious Diseases Lecture Outline Overview 6 cases (90%) High yield information (10%) Syllabus Answers to case questions with descriptions There is some supplemental information in your syllabus not in this lecture There is a bonus case in the syllabus on intraabdominal infections Case 1 34 y/o presents to ED with 3 days of progressive forearm erythema and tenderness Injury while moving furniture Afebrile VSS, appears well Forearm with erythema, increased warmth, tenderness. No fluctuance and no streaking redness. 1

2 Question 1: What would you do? A. Send home on PO clindamycin B. Send home on PO trimethoprim-sulfa C. Admit, give piperacillin-tazobactam D. Admit, give vancomycin 64% Define your SSTI to determine your bugs? Cellulitis without purulence β-hemolytic strep (Group A, B, C, G) S. aureus Purulent SSTIs (abscess, furuncles, carbuncles) S. aureus 26% Send home on P... Send home on P... Admit, give pi... 9% 2% Admit, give va... Surgical site infections S. aureus β-hemolytic strep (Group A, B, C, G) Unless susceptibilities show otherwise S. aureus = MRSA Use this to base empiric antibiotic therapy MANAGEMENT OF SSTIIN ERA OF CA-MRSA SSTI type Purulent (abscess, furuncle, carbuncle, cellulitis w/ purulence) 1 Pathogens S. aureus (MRSA) Empiric Rx Mild disease Mod-severe disease I&D alone *Consider addition of MRSA active antibiotic (TMP-SMX,doxycycline, clindamycin) in select situations Non-purulent (erysipelas, cellulitis) β-hemolytic strep and S. aureus (MRSA) Clindamycin or Amoxicillin plus TMP/SMX I&D plus VancomycinIV # VancomycinIV # *Systemic illness, purulent cellulitis/wound infection, comorbidities, extremes of age, abscess difficult to drain or face/hand, associated septic phlebitis, lack of response of to I&Dalone. # Daptomycin, linezolid, tigecycline, and telavancinare also FDA approved for Rx of MRSA cssti 2

3 A slight alteration 34 y/o comes in with the similar symptoms Temp 38.9, HR 105, SBP 100, RR 20 Appears ill and in more pain than what you would expect for cellulitis Question 1b: What do you do? A. Send home on cephalexin, TMP/SMZ, pain meds B. Give IV vancomycin and cefazolin C. Give IV vancomycin and cefazolin. Call surgery for morning consult. D. Call surgery immediately. Give IV clindamycin, piperacillin-tazobactam, and vancomycin Send home on c... 0% Give IV vancom... 4% 12% Give IV vancom... 84% Call surgery i... Necrotizing Fasciitis Clues: pain out of proportion to exam, toxic appearing, blistering, rapidly spreading, decreased sensation Bugs? -2 forms Monomicrobial: Group A Strep most common Polymicrobial: GNR, anaerobes Necrotizing Fasciitis: Treatment Surgical debridement! Empiric antibiotics Pip/tazo or mero-, imipenem (strep, GNR, anaerobes) plus Clindamycin (protein synthesis inhibitor) plus Vancomycin (MRSA) Narrow antibiotics based on cultures 3

4 Case 2 61 y/o diabetic presents to ED with, fever, stiff neck, and new onset seizure. Febrile to 39 C with stable vital signs. Lethargic but able to answer questions. Nuchal rigidity and photophobia seen but no focal neurological abnormalities. Question 2a: Does he need a CT scan before getting an LP? A. Yes B. No 54% 46% Yes No Who needs a head CT before LP? Who is at high risk for herniation from LP? Patients at high risk for mass lesions or increased intracranial pressure can be identified clinically and should then undergo CT scan Who are high risk patients? New-onset seizure Immunocompromised Focal neurological finding Papilledema Moderate-severe impairment of consciousness Hasbun R. NEJM Gopal AK. Arch Int Med Question 2b: Which is the preferred antibiotic regimen for this patient? (61 y/o diabetic male) A. Ceftriaxone B. Ceftriaxone and Vancomycin C. Ceftriaxone and Ampicillin D. Vancomycin and Ceftriaxone and Ampicillin Ceftriaxone 3% Ceftriaxone an... 37% 16% Ceftriaxone an... 45% Vancomycin and... 4

5 Bugs causing meningitis? Schuchat A. NEJM 1997; 337:14 Empiric antimicrobial therapy Risk factor Pathogens Antimicrobials < 1 month GBS, E. coli, L. monocytogenes 1-23 months S. pneumoniae, N. meningitidis, GBS, H. influenzae 2-50 yrs N. meningitidis, S. pneumoniae > 50 yrs S. pneumoniae, N. meningitidis, L. monocytogenes Ampicillin + cefotaxime Vancomycin + 3rd gen ceph Vancomycin + 3rd gen ceph Vancomycin+ 3rd genceph+ ampicillin Adapted from TunkelAR. CID 2004; GBS=group B strep (Strep agalactiae), 3rd gen ceph=ceftriaxone or cefotaxime IDSA algorithm for management of bacterial meningitis Indication for head CT NO YES Blood cx + Lumbar puncture Steroids and empiric antimicrobials CSF suggestive of bacterial meningitis Blood cx Steroids and empiric antimicrobials Head CT w/o mass lesion or herniation Case 3a 65 y/o diabetic woman presents to clinic for routine evaluation. She has been feeling well. A urinalysis and culture are sent. UA: WBC->100, RBC-0, Protein-300 The next day you are called because the urine culture has >100,000 Klebsiella pneumoniae Refine therapy Lumbar puncture Tunkel AR. CID

6 Question 3a: What do you recommend? A. No antibiotics B. Empiric ciprofloxacin and await susceptibilities C. Repeat culture in 1 week and if bacteria still present then treat No antibiotics 32% Empiric ciprof... 59% 8% Repeat culture... Asymptomatic bacteriuria in diabetic women Asymptomatic bacteriuria ~ 25% of diabetic women (pyuria is usually present) RCT, placebo controlled of 105 diabetic women 14 days of antibiotic vs. placebo 1 endpoint: symptomatic UTI 42% antibiotic group vs. 40% placebo RR 1.19 ( ),p=0.42 Harding GKM. NEJM 2003 Treatment of asymptomatic bacteriuria? Clear benefit Pregnant women Pre traumatic urologic interventions with mucosal bleeding Possible benefit Bacteriuria > 48h after catheter removal Immunosuppressed No benefit Postmenopausal ambulatory women Institutionalized Spinal cord injuries Patients with urinary catheters Diabetics Case 3b A 21 year-old college student, calls to say that she has a urinary tract infection, again. You have treated for uncomplicated cystitis 3 times in the past year with trimethoprimsulfamethoxazole, all episodes confirmed by an abnormal urinalysis. You obtain a UA: Leukocyte esterase 3+, RBC 1+ 6

7 Question 3b: Which would be the best empiric antibiotic regimen? A. Ciprofloxacin 250 BID x 3d B. Levofloxacin 500 QD x 5d C. TMP-SMX DS BID x 7d D. Cephalexin 500 mg QID x 7d 44% 14% 27% 14% Treatment of uncomplicated UTI? 1. TMP-SMX DS BID x 3d OR Cipro250 BID x 3d 2. Nitrofurantoin 100 mg BID x 5d When NOT to use TMP-SMX local resist > 20% DM Recent hospitalization TMP-SMX use in last 3 mo 3. Cephalexin 500mg QID x 5d Ciprofloxacin... Levofloxacin 5... TMP-SMX DS BID... Cephalexin What would make the UTI complicated? Anatomic abnormality Indwelling urinary catheter Recent instrumentation Pregnant women Men Healthcare-associated Recent antimicrobial use Symptoms > 7 days Diabetes or immunosuppression History of childhood UTI How would you treat? Fluoroquinolones for empiric therapy Obtain cultures Duration 7-14 days Prevention of recurrent UTIs Prevent vaginal colonization w/ uropathogens Avoid spermicide Intra-vaginal estrogen (post-menopausal) Prevent growth of uropathogens in bladder Cranberry juice Methenamine hippurate Postcoitol or daily antibiotics Correct anatomic/neurologic problems Select cases consider urology evaluation 7

8 Question 3c: If this same patient presented with pyelonephritis what would be the best regimen? A. Ceftriaxone 1 gm IV q24 B. Moxifloxacin 400 mg IV/PO q24 C. Nitrofurantoin 100 mg PO q12 D. Cefpodoxime 200 mg PO q12 Ceftriaxone % Moxifloxacin % 6% Nitrofurantoin... 5% Cefpodoxime Empiric treatment of pyelonephritis Recommended Ciprofloxacin 500 mg q12 (7 days if uncomplicated) Levofloxacin OK but not Moxifloxacin Ceftriaxone 1 gm IV q24 (14 days) Not recommended TMP-SMX (high resistance rate so not good empiric) Nitrofurantoin (does not get into kidney parenchyma) Health-care associated pyelonephritis Use antipseudomonal agent other than fluoroquinolone Case 4a 60 y/o woman with HTN presents with 3 days of cough with green sputum, dyspnea on exertion, fever, pleuritic chest pain. She otherwise has no past medical history. Exam: 38.5, 145/90, 100, 18, 95% RA Chest: crackles at left base WBC: 15.5 CXR: LLL infiltrate Question 4a: How would you manage this patient? A. Oral antibiotics at home B. Hospitalize for IV antibiotics; when afebrile, switch to PO antibiotics and discharge home C. Hospitalize for IV antibiotics; when afebrile, switch to PO antibiotics and discharge after 24 hours observation D. Hospitalize for minimum of 7 days of IV antibiotics Oral antibioti... 55% Hospitalize fo... 18% Hospitalize fo... 25% 2% Hospitalize fo... 8

9 Pneumonia Severity Index Demographic Age (+1 point/yr, -10 if woman) Nursing home (+10) Comorbidities Cancer (+30) Liver disease (+20) CHF (+10) Cerebrovascular dz (+10) Renal disease (+10) Don t memorize this! Examination Mental status (+20) Pulse > 125 (+20) Resp rate > 30 (+20) SBP < 90 (+15) Temp < 35 or > 40 (+10) Labs ph < 7.35 (+30) BUN > 30 (+20) Na < 130 (+20) Glucose > 250 (+10) p02 < 60 (+10) Hct < 30 (+10) Pleural effusion (+10) I Pneumonia Severity Index Class PSI score Mortality Triage Age < 50, no comorbidity, stable vital signs 0.1% outpatient II % outpatient III % consider admission IV % admission V > %? ICU CAP: When to Admit CAP: When to Discharge Outpatient: Younger No cancer or endorgan disease No severe vital sign abnormalities No severe laboratory abnormalities Inpatient: Doesn t meet outpt criteria Hypoxia Active coexisting condition Unable to take oral meds Psychosocial issues Homeless, drug abuse, risk of non-adherence Afebrile, hemodynamically stable, not hypoxic, and tolerating POs No minimum duration of IV therapy needed No need to watch on oral antibiotics Most patients with CAP, 7 days of antibiotic treatment is adequate 9

10 Case 4b: 82 y/o with h/o CHF presents with 5 days of productive cough and dyspnea. Denies recent travel or hospitalization / % RA Chest: crackles at right base CXR: Right lower & middle lobe infiltrates Labs: WBC 12, BUN=38, otherwise normal Question 4b: What is the most appropriate treatment? A. Cefuroxime IV B. Levofloxacin IV C. Piperacillin-tazobactam IV D. Azithromycin IV E. Cefepime IV + vancomycin IV 10% 43% 16% 9% 22% Cefuroxime IV Levofloxacin I... Piperacillin-t... Azithromycin I... Cefepime IV +... Etiology of CAP Clinical and CXR not predictive of organism Streptococcus pneumoniae Haemophilus influenzae Mycoplasma pneumoniae Chlamydophila pneumoniae Legionella (Enteric Gram negative rods) Viruses Staphylococcus aureus Covered by usual regimes Not covered by usual regimens Empirical Treatment for Outpatients No comorbidityor recent antibiotics Comorbidcondition(s) age > 65, EtOH, CHF, severe liver or renal disease, cancer or Antibiotics in last 3 months Macrolide or Doxycycline β-lactam(e.g. amox) + either macrolideor doxycycline or Respiratory FQ* B-lactam= High-dose amoxicillin [e.g., 1 g 3 times daily] or amoxicillinclavulanate [2 g 2 times daily] is preferred; alternatives include ceftriaxone, cefpodoxime, and cefuroxime [500 mg 2 times daily]; * Respiratory FQ = Levofloxacin or Moxifloxacin 10

11 Empirical Treatment for Inpatients Inpatient non-icu Inpatient ICU β-lactam + macrolide or doxycycline or Respiratory FQ β-lactam + azithromycin or resp FQ (Penicillin allergy: fluoroquinolone + aztreonam) MRSA concern Add vancomycin or linezolid to above B-lactam = cefotaxime, ceftriaxone, and ampicillin-sulbactam; ertapenem for selected patients * Resp FQ = Levofloxacin or Moxifloxacin Diagnostic Testing in CAP Chest radiography: Indicated for all patients with suspected pneumonia Blood culture: Recommended for inpatients (do before antibiotics) Sputum exam: Controversial but recommended for inpatients Other: Legionella urinary Ag, pnuemo urinary Ag, resp virus testing Case 4c 60 y/o intubated 17 days ago following MVA. Received ciprofloxacin for a UTI 8 days ago. Now she has new fever, WBC 15, and increased oxygen requirements. Chest X-ray was done Question 4c: Which antibiotics would you start after obtaining blood and sputum cultures? A. Vancomycin B. Vancomycin + ceftriaxone C. Ceftriaxone + azithromycin D. Vancomycin + meropenem E. Moxifloxacin 4% 46% 19% 27% 4% Vancomycin Vancomycin + c... Ceftriaxone +... Vancomycin + m... Moxifloxacin 11

12 Ventilator associated pneumonia (VAP) Clinical diagnosis! Increased oxygen requirement Fever Increased WBC count New infiltrate on CXR Increased secretions Use respiratory culture to tailor therapy Do we need to cover for pseudomonas? Not cause of community acquired pneumonia but if any below present can consider Recent or current hospitalization Recent antibiotics Structural lung disease (CF) What antibiotics cover pseudomonas? B-lactams Piperacillin and ticaricillin Ceftazidime, cefepime Aztreonam Imipenem, meropenem, doripenem (not ertapenem) Fluoroquinolones ciprofloxacin and levofloxacin (not moxifloxacin) Aminoglycosides gentamicin, tobramycin, amikacin HAP/VAP pathogens Gram negatives -Pseudomonas -Acinetobacter -Enterics Empiric Treatment Anti-pseudomonalcephalosporin (ceftaz or cefepime) or Anti-pseudomonalpenicillin (piperacillin-tazobactam) or Anti-pseudomonal carbapenem (imi-, mero-, doripenem) PLUS Anti-pseudomonal aminogylcoside (gent, tobra, amikacin) or Anti-pseudomonalfluoroquinolone (cipro, levo) PLUS S. aureus (MRSA) Vancomycin or linezolid 12

13 Pneumococcal Vaccine Pneumococcal polysaccharide vaccine (PPV23) Protective against invasive disease but PNA? Groups recommended to be vaccinated Persons aged 65 years Chronic cardiovascular or pulmonary disease (including asthma), DM Smokers, alcoholics, chronic liver disease, CSF leaks, or cochlear implants Living in special environments or social settings such as chronic care facilities Immunocompromised persons Revaccination if > 65 yrs and patient received vaccine 5 yrs previously and was aged <65 yrs at the time of vaccination or immunocompromised and 5 yrs since last vaccination Case 5 72 y/o female presents to your office with 3 days of watery diarrhea (8 stools/day), abdominal cramping, and fever. She healthy except for moderate mitral regurgitation. Last week had dental surgery and received amoxicillin for endocarditis prophylaxis Exam: 38.5, 110/60, 95, 20, 98% RA Fatigued appearing, tenderness in LLQ Labs WBC and Cr-1.5. Question 5a: You send stool for Clostridium difficile and it is positive, what do you recommend? A. Start IV metronidazole B. Start PO metronidazole C. Start PO vancomycin D. Start IV metronidazole and PO vancomycin E. Start PO metronidazole and PO vancomycin Start IV metro... 11% Start PO metro... 60% Start PO vanco... 8% 7% Start IV metro... 14% Start PO metro... Clostridium difficile colitis Exposure to the organism plus Antibiotics to wipe out competing bugs Cephalosporins, quinolones, clindamycin, penicillins Clinical manifestations Mild watery diarrhea Toxic megacolon Fever Abdominal pain Leukocytosis 13

14 Management of C. difficile colitis Disease Severity Severity criteria Treatment Mild/ moderate Severe* Severe with Complications < 6 loose BM/ day no fever WBC < 15K no peritoneal signs 3 of the following: age>65 WBC>15K 7 loose BM/ day fever albumin <2.5 acute renal failure ICU admit due to C. diff Ileus Toxic megacolon Severe colitis on CT Perforation Hypotension Metronidazole 500 mg PO q8h Vancomycin 125 mg PO q6h Vancomycin 125 mg PO q6h AND Metronidazole 500 mg IV q8h *Zar FA. Clin Infect Dis Question 5b: Should this patient with mitral regurgitation received antibiotic prophylaxis for infective endocarditis based on the updated AHA guidelines (2007)? 1. Yes 2. No 14% Yes 86% No Cardiac conditions in which endocarditis prophylaxis may be recommended for select procedures Prosthetic cardiac valve Previous infective endocarditis Congenital heart disease (CHD) Unrepaired cyanotic CHD, including palliative shunts and conduits Completely repaired congenital heart defect with prosthetic material or device, during the first 6 months after the procedure 4 Repaired CHDwith residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device Cardiac transplantation recipients with cardiac valvulopathy Which procedures should prophylaxis be given to at-risk patients? Prophylaxis Recommended Prophylaxis Not Recommended Dental procedures Dental procedures Procedures that involve manipulation of Routine anesthetic injections gingival tissue,periapicalregion of teeth Dental radiographs or perforation of the oral mucosa Placement or removable Respiratory tract procedures prosthodontics Only procedures that involve incision of Adjustment of orthodontics the respiratory mucosa Placement of orthodontic brackets Shedding of deciduous teeth Bleeding from lips or oral mucosa Procedures on infected skin, skin structure, or musculoskeletal tissue Gastrointestinal tract procedures Genitourinary tract procedures 14

15 Recommended antibiotics when endocarditis prophylaxis is needed Oral Amoxicillin 2 g 1 hour pre-procedure Clindamycin 600 mg 1 hour pre-procedure or Penicillin allergy Cephalexin 2 g 1 hour pre-procedure or Azithromycin or clarithromycin 500 mg 1 hour pre-procedure Parenteral Ampicillin 2 g IM or IV 30 min pre-procedure Clindamycin 600 mg IV 1 hour pre-procedure Penicillin or allergy Cefazolin 1 g IM or IV 30 min pre-procedure Case 6 32-year-old woman developed sudden onset of headache, high fever, and extreme fatigue two days after returning from a vacation in Central Mexico. She complained of flushing over face and chest and 3 days later, developed a generalized splotchy rash Physical Exam Labs 38.8, 110/65, 87, 18, 98%/RA CBC: 1.5 >48.9<37 Cr -0.9 AST 124, ALT -87 Question 6: This infection would have been best prevented by which one of the following: A. Mefloquine (Lariam) 1. Ciprofloxacin 2. DEET 3. An intramuscular vaccine 39% 17% 29% 15% Mefloquine (La... Ciprofloxacin DEET An intramuscul... 15

16 Causes of illness in returning traveler Diarrhea Acute: Traveler s Diarrhea (ETEC, campy, salmonella, shigella) Rx: Ciprofloxacin or azithromycin Subacute/chronic: Giardia, E. histolytica, post-infectious IBS Fever Dengue: #1 everywhere except Sub-Saharan Africa P. falciparum: #1 Sub-Saharan Africa Other: Rickettsia,Typhoid fever, CMV/EBV, Cutaneous diseases Ulcers: cutaneous leishmaniasis Serpiginous lesions: Cutaneous larva migrans Incubation period for febrile illnesses in returning travelers < 14 days Dengue and Chikungunya fevers Ricketssial diseases P. falciparum > 14 and < 30 days P. falciparum > P. vivax, P. ovale Typhoid Acute CMV/EBV Hepatitis A and E > 30 days P. vivax, P. ovale Hepatitis A and E Evaluation of febrile returning traveler Detailed history/exam Geography? Incubation? Exposures? Specific features? Prophylaxis/vaccines? Initial testing Thick and thin smear Blood cultures CBC with differential LFTs Use history/exam to guide other tests HIGH YIELD 16

17 High yield Device (and line) related infections Answer usually pull the line plus antibiotics Endocarditis Acute: S. aureus (MRSA) #1 Subacute: Viridans group streptococci #1 Prosthetic valve endocarditis: S. aureus or S. epidermidis Doxycycline is usually the answer for Lyme disease (also amoxicillin, ceftriaxone) Rocky mountain spotted fever (even in children) Ehrlichiosis and Anaplasmosis ( spotless fevers ) Syphilis (when penicillin is not an option) Fungal infections High yield Candidemia Empiric treatment for critically ill is an echinocandin Always remove central venous catheters Always get an eye exam to rule-out ocular involvement Coccidiomycosis treatment of choice fluconazole Aspergillosis treatment of choice voriconazole Cryptococcal meningitis treatment of choice is amphotericin B plus 5-FC followed by fluconazole Latent TB diagnostics High yield Prior BCG should not influence how you read PPD Interferon gamma release assays (IGRAs) no false positives with prior BCG If + PPD or +IGRA, check chest X-ray and history to evaluate for active TB Active TB Treatment of active TB in HIV often use rifabutin not rifampin due to interactions with ARVs High yield Severe infection in asplenic patients Encapsulated organisms (Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae) Vaccinate 2 weeks before if possible Babesiosis ticks in New England Capnocytophaga dog bites Anaplasmosis/Erlichiosis 17

18 ANSWERS WITH EXPLANATIONS PLUS EXTRA CASE Question 1a: What would you do? Which antibiotics for which SSTI bugs? A. Send home on PO clindamycin MRSA and strep coverage, clinically stable just right B. Send home on PO trimethoprim-sulfa Poor strep coverage C. Draw blood cx, admit, give piperacillin-tazobactam No MRSA coverage D. Draw blood cx, admit, give vancomycin Good coverage but a bit aggressive given clinically stable MSSA MRSA β-hemolytic streptococci (group A, B, C, G) PO Cephalexin Dicloxacillin Amox-Clav *plus all forpo MRSA Clindamycin TMP-SMX Doxy, Minocycline Linezolid Penicillin, Amoxicillin Dicloxacillin Cephalexin Clindamycin Linezolid IV Nafcillin/Oxacillin Cefazolin Ampicillin-sulbactam *plus all formrsa Vancomycin Daptomycin Tigecycline Telavancin Penicillin, Ampicillin Ceftriaxone *plus all for IV MSSA/MRSA 18

19 Question 1b. What do you do? A. Send home on cephalexin, TMP/SMZ, pain meds B. Give IV vancomycin and cefazolin C. Give IV vancomycin and cefazolin. Call surgery for morning consult. D. Call surgery immediately. Give IV clindamycin, piperacillin-tazobactam, and vancomycin Broad spectrum antibiotics plus earlysurgery is treatment of choice, answers without early surgery are wrong Question 2a: Does he need a CT scan before getting an LP? A. Yes B. No Seizure (as well as Immunocompromised state, focal neurological finding, papilledema, moderate-severe impairment of consciousness) is a risk factor for herniationfollowing LP therefore a CT scan is indicated to rule out Question 2b: Which is the preferred antibiotic regimen? A. Ceftriaxone B. Ceftriaxone and Vancomycin C. Ceftriaxone and Ampicillin Question 3a: What do you recommend? A. No antibiotics No treatment is needed for asymptomatic bacteriuria in diabetics B. Empiric ciprofloxacin and await susceptibilities C. Repeat culture in 1 week and if bacteria still present then treat D. Vancomycin and Ceftriaxone and Ampicillin > 50 yrs -cover for strep pneumo(ceftriaxone and vanco), neisseria(ceftriaxone) and listeria(ampicillin) 19

20 Question 3b: Which would be the best empiric antibiotic regimen? A. Ciprofloxacin 250 BID x 3d correct B. Levofloxacin 500 QDx 5d Levo250 qdx 3 days would be correct C. TMP-SMX DS BID x 7d TMP-SMX DS BID x 3 days is proper course but she had multiple recent treatments D. Cephalexin 500 mg QIDx 7d Treatment is 5 day course not 7 and is usually second line treatment because of the longer course Question 4a: How would you manage this patient? A. Oral antibiotics at home Low PORT score (age 60, vitals OK, no comorbidities) B. Hospitalize for IV antibiotics; when afebrile, switch to PO antibiotics and discharge home C. Hospitalize for IV antibiotics; when afebrile, switch to PO antibiotics and discharge after 24 hours observation D. Hospitalize for minimum of 7 days of IV antibiotics Question 4b: What is the most appropriate treatment? A. Cefuroxime IV No atypical coverage B. Levofloxacin IV Just right C. Piperacillin-tazobactam IV No atypical coverage, no need for pseudomonas D. Azithromycin IV Not broad enough for hospitalized patient with CAP E. Cefepime IV + vancomycin IV No atypical coverage; no need for anti-pseudo or anti-mrsa Rx Question 4c: Which antibiotics would you start after obtaining blood and sputum cultures? A. Vancomycin No gram neg coverage B. Vancomycin plus Ceftriaxone No pseudomonas coverage C. Ceftriaxone plus azithromycin No pseudomonas or MRSA coverage D. Vancomycin plus meropenem Pseudomonas and MRSA coverage E. Moxifloxacin No pseudomonas or reliable MRSA coverage 20

21 Question 5: You send stool for Clostridium difficile and it is positive, what do you recommend? A. Start IV metronidazole B. Start PO metronidazole C. Start PO vancomycin Severe disease (age>65, WBC>15K, 7 loose BM/ day, fever) A. Start IV metronidazole and PO vancomycin B. Start PO metronidazole and PO vancomycin Question 5b: Should this patient with mitral regurgitation received antibiotic prophylaxis for infective endocarditis based on the updated AHA guidelines (2007)? A. Yes B. No Valvular stenosis or insufficiency in the absence of prosthetic valve or prior endocarditis is not an indication for antibiotic prophylaxis. Question 6: This infection may have been prevented by the following: A. Mefloquine (Lariam) Would prevent malaria B. Ciprofloxacin Would prevent typhoid fever or traveler s diarrhea C. DEET Dengue is a mosquito borne illness and insect avoidance is only effective prevention D. An intramuscular vaccine Would prevent typhoid fever, hepatitis A, Japanese encephalitis, mening EXTRA CASE 21

22 Extra Case 76 y/o woman presents to ED with LLQ pain x 2 days 38.9 C, BP 115/56, HR 105 Tender LLQ but no peritoneal signs CT scan performed Question : She has acute diverticulitis, which antibiotic regimen should you start? A. Ampicillin-sulbactam B. Piperacillin-tazobactam and metronidazole C. Clindamycin and ceftriaxone D. Ertapenem E. Vancomycin and ceftriaxone Abdominal Bugs?? Enteric gram negatives (E. coli, Klebsiella sp.) Anaerobes (Bacteroides sp., Clostridium sp.) Gram positives (Strep sp. and Enterococcus) Some yeast (Candida) Drugs for enteric gram negatives Cephalosporins: ceftriaxone, ceftazidime, cefepime Anti-pseudomonal penicillins: Piperacillin, ticaricillin Carbapenems: meropenem, imipenem, doripenem, ertapenem Fluoroquinolones: ciprofloxacin, levofloxacin, moxifloxacin Aminoglycosides: gentamicin, tobramycin, amikacin Other: tigecycline, aztreonam 22

23 Drugs for intestinal anaerobes Metronidazole Penicillins plus B-lactamase inhibitors Ampicillin + sulbactam (Augmentin ) Amoxicillin + clavulanic acid (Unasyn ) Piperacillin + tazobactam (Zosyn ) Ticaricillin + clavulanic acid (Timentin ) Carbapenems: mero-, imi-, dori-, ertapenem Fluoroquinolones: moxifloxacin Other: tigecycline NOT clindamycin (activity is unreliable) Antibiotics with activity against enterococcus Don t need to cover for community-acquired abdominal infection Penicillins: Penicillin, Amoxicillin/Ampicillin, Piperacillin Carbapenems: Imipenem Vancomycin Linezolid* Tigecycline* Quinupristin/dalfopristin* *Active against vancomycin-resistant enterococci (VRE) Antimicrobial regimens for community onset abdominal infections Extra Case Question : You diagnose her with acute diverticulitis, which antibiotic regimen do you start? Single agents Combination therapy Mild-moderate severity Ertapenem, moxifloxacin, tigecycline Cefazolin, cefuroxime, ceftriaxone, cefotaxime, cipro., levo. PLUS metronidazole High risk or severity Imi-, mero-, doripenem, piperacillin-tazobactam Cefepime, ceftazidime, cipro., or levo., PLUS metronidazole Solomkin JS. Clin Infect Dis 2010 A. Ampicillin-sulbactam Not reliable against enteric gram negatives B. Piperacillin-tazobactam and metronidazole No need for pseudo or double anaerobic coverage C. Clindamycin and ceftriaxone Clinda not reliable for enteric anaerobes D. Ertapenem Just right E. Vancomycin and ceftriaxone No need for MRSA coverage, No anaerobic coverage here 23

24 ID Resources IDSA website practice guidelines John s Hopkin s antibiotic guide Uptodate UCSF Infectious Diseases Management Program 24