Sandbox:Reddy 2

Hospitalized patients

Infection		Organisms	First DOC	Alternative
Osteomyelitis	Presumed hematogenous source or contiguous without vascular insufficiency	S. aureus	Vancomycin	Vanc	If S. aureus is methicillin-susceptible then cefazolin 2 g IV q8h or nafcillin 2 g IV q4h are the antibiotics of choice. Obtain bone biopsy to determine microbiologic cause prior to initiation of antimicrobial therapy if blood cultures are negative and patient clinically stable.
	With vascular insufficiency or diabetes mellitus (e.g. severe diabetic foot ulcer)	S. aureus  Enterobacteriaceae Anaerobes	Vancomycin PLUS ONE OF: Piperacillin/Tazobactam 4.5 g IV q6-8h OR Ertapenem 1 g IV daily	For severe PCN allergy: Vancomycin PLUS ONE OF: Ciprofloxacin400 mg IV q12h OR Levofloxacin 750 mg IV daily OR Aztreonam 2 g IV q8h ALL WITH OR WITHOUT: Metronidazole500 mg IV q8h (if patient critically ill)	Other organisms are possible, esp. with hardware microbiologic diagnosis and ID consultation recommended Obtain bone biopsy to determine microbiologic cause prior to initiation of antimicrobial therapy if patient clinically stable Once stable, switch to oral antibiotics based on susceptibility results.
Septic Arthritis		S. aureus Streptococci spp. N. gonorrhoeae Enterobacteriaceae (rarely)	Vancomycin PLUS Ceftriaxone1 g IV daily	For severe PCN allergy: Vancomycin PLUS ONE OF: Ciprofloxacin 400 mg IV q12h OR Levofloxacin 500 mg IV daily OR Aztreonam g IV q8h if gonococcus is strongly suspected	Gram stain recommended to guide therapy. Narrow coverage to microbiologically confirmed pathogens.

Brain abscess	Streptococci (anaerobic or aerobic) Bacteroides spp Prevotella spp Enterobacteriacea	Ceftriaxone 2 g IV q12h PLUS Metronidazole 500 mg PO/IV q8h WITH OR WITHOUT*: Vancomycin	Aztreonam 2 g IV q8h PLUS Vancomycin PLUS Metronidazole 500 mg PO/IV q8h	Consider expanded Gram-positive coverage if patient at risk for drug-resistant streptococci or MRSA
Meningitis Community-onset	S. pneumoniae Neisseria meningitidis Listeria (especially in immuno-compromised, elderly patients, and alcoholics)	ceftriaxone 2 g IV q12h PLUS Vancomycin WITH OR WITHOUT* one of: TMP/SMX 15 mg/kg/day (in divided doses) OR 'Ampicillin' 2 g IV q4h	For severe PCN allergy: Vancomycin PLUS Aztreonam2 g IV q6h-q8h WITH OR WITHOUT*: TMP/SMX (if Listeria) 15 mg/kg/day (in divided doses)	Therapy should be guided by Gram stain. If bacterial meningitis suspected, dexamethasone 10 mg PO/IV q6h x 4 days given before or with initial dose of antibiotics.  *Coverage for Listeria with TMP/SMX or ampicillin should be added for patients who are <2 or >50 years of age or immunocompromised.
Meningitis Post-neurosurgical or device associated	S. aureus Coagulase negative Staphylococci Gram negative rods	Cefepime PLUS 'Vancomycin'	For severe PCN allergy: Aztreonam 2 g IV q6h-q8h PLUS Vancomycin

Native Valve	S. aureus Streptococci spp. Enterococcus spp. Occasional gram negative rods HACEK < 5%	Vancomycin WITH or WITHOUT* Ceftriaxone 2 g IV daily	For severe PCN allergy: Vancomycin WITH or WITHOUT* CiprofloxacinID-R: VASF 400 mg IV q12h	Narrow coverage to microbiologically confirmed pathogens *Addition of Gram-negative coverage should be considered if the patient has a sub-acute presentation.
Prosthetic Valve	S. aureus S. epidermidis	Vancomycin PLUS Rifampin300 mg PO q8h PLUS Gentamicin 1 mg/kg/dose IV q8h for initial two weeks only Single daily dose of gentamicin is not recommended		Rifampin has numerous clinically significant drug interactions.  Medication lists should be reviewed for potential drug-drug interactions with rifampin.

Spontaneous Bacterial Peritonitis (SBP)	E. coli Klebsiella spp. 'Streptococci. spp.	Ceftriaxone 1 g IV daily x 5 days	For severe PCN allergy: Vancomycin PLUS Aztreonam 2 g IV q8h
Secondary Peritonitis Mild-Moderate intra-abdominal abscess	E. coli Klebsiella  B. fragilis Streptococci spp S. aureus	Ertapenem 1g IV daily OR Piperacillin/tazobactam 3.375 g IV q6h - 4.5g IV q6h	For severe PCN allergy: Vancomycin PLUS Aztreonam 2 g IV q8h PLUS Metronidazole500 mg IV q8h
Secondary Peritonitis Severe (major peritoneal soilage, large or multiple abscesses, patient hemodynamically unstable)	E. coli  Klebsiella B. fragilis  P. aeruginosa Enterococcus spp. Streptococcus spp S. aureus	Vancomycin PLUS Piperacillin/tazobactam 4.5 g IV q6h	For severe PCN allergy: Vancomycin PLUS Aztreonam 2 g IV q8h PLUS Metronidazole500 mg IV q8h	For hemodynamically unstable health-care associated infection, consider meropenem.
Clostridium difficile-associated diarrhea	Clostridium difficile	Initial episode, mild to moderate disease (WBC ≤15K and SCr less than 1.5 times premorbid level) Vancomycin 125mg PO q6h x 10-14 days.  If unable to obtain at discharge, can complete course with Metronidazole500mg po q8h Initial episode, severe disease (WBC >15k and/or 50% increase in SCr) Vancomycin 125mg PO q6h x 10-14 days. Initial episode, severe disease with complications (Severe disease with hypotension, shock, ilios, and/or megacolon) Vancomycin 500mg PO/NG q6h x 10-14 days PLUS Metronidazole 500 mg IV q8h x 10-14 days WITH OR WITHOUT Vancomycin PR Rectal vancomycin should be considered in patients with ileus. It is given as 500 mg in 100 mL of 0.9% NaCl and instilled q6h (retain each dose for 1h) First recurrence Same therapy as initial episode, stratified by illness severity First recurrence, special population (hematologic malignancy with >30 days expected neutropenia, recent HSCT, recent treatment for GVHD, solid organ transplant <3 months) FidaxomicinID-R: UCSF SFGH  VASF 200mg PO BID x10 days Second recurrence Vancomycin with tapered or pulsed regimen PLUS Consult ID, GI PLUS Evaluate for fecal microbiota transplant	IV metronidazole alone is not indicated for treatment of C. difficile diarrhea. IV metronidazole should only be used in combination with PO vancomycin in the ICU. Recurrence in 5-30% of patients after first episode and 33-60% after second episode. ID CONSULT recommended in patients with severe disease with complications or multiply recurrent disease, and for consideration of rectal vancomycin administration.

'Endometritis'

Bacteroides Prevotella bivia Group B & Astreptococci Enterobacteriaceae M. hominis

1st line: Cefoxitin 2 g IV q6h  2nd line: Ertapenem 1 g IV daily 3rd line: Ampicillin/sulbactam 3 g IV q6h

For severe PCN allergy: Vancomycin PLUS Gentamicin PLUS Metronidazole 500 mg IV q12h

If test for chlamydia is positive add azithromycin or doxycycline. Continue antibiotics until afebrile for 24-48 hours. If still febrile > 48 hours and on cefoxitin or clindamycin/gentamicin postpartum, switch to ertapenem. Wait 48 hours on an antibiotic regimen before considering regimen failed.

Peritonsillar abscess, deep neck infections

Group A streptococci Anaerobes S. aureus

Ampicillin/sulbactam 3 g IV q6h WITH OR WITHOUT* Vancomycin  Alternatively: Ertapenem 1 g IV daily WITH OR WITHOUT* Vancomycin  Alternatively: Metronidazole 500 mg IV/PO q8h PLUS Ceftriaxone1 g IV q24h WITH OR WITHOUT* Vancomycin

For severe PCN allergy: ClindamycinID-R: VASF 600 – 900 mg IV q8h PLUS CiprofloxacinID-R: VASF 400 mg IV q12h OR LevofloxacinID-R: VASF 500 mg IV daily

Often polymicrobial Combinations of piperacillin/tazobactam, ampicillin/sulbactam, or ertapenem PLUS metronidazole should not be used. *Consider vancomycin use for patients at high risk for MRSA

Line-related bacteremia

S. epidermidis S. aureus Enterococci spp. Gram-negative rods* Yeast**

Vancomycin WITH OR WITHOUT* one of: Piperacillin/tazobactam ID-R: SFGH 4.5 g IV q6h OR 'CefepimeI' 2 g IV q8h

For severe PCN allergy: Vancomycin WITH OR WITHOUT* one of: Aztreonam ID-R: SFGH 2 g q8h

Remove the offending intravascular device immediately, if possible. *Consider Gram-negative coverage for immunocompromised patients or those with prolonged hospitalization, recent antibiotic exposure or sepsis.

Community-Acquired Pneumonia	Immunocompetent patient – Medical Ward	S. pneumoniae Mycoplasma pneumoniae Chlamydia pneumoniae H. influenzae Legionella pneumophilia Klebsiella pneumoniae (alcoholics)	No Recent antibiotic therapy:* Ceftriaxone 1 g IV daily PLUS 'Doxycycline'100 mg PO/IV q12h	For severe PCN allergy: Levofloxacin 750 mg PO/IV daily OR MoxifloxacinID-R: SFGH 400 mg PO/IV daily	If patient has had recent antibiotic therapy, antibiotics from a different class should be selected (i.e. recent use of a fluoroquinolone should dictate selection of a non-fluoroquinolone regimen, and vice versa). Consider influenza testing and treatment with oseltamivir.
	Community-Acquired Pneumonia Immunocompetent patient – ICU	S. pneumoniae Mycoplasma pneumoniae Chlamydia pneumoniae H. influenzae Legionella pneumophilia Klebsiella pneumoniae (alcoholics) S. aureus	Ceftriaxone 1 g IV daily PLUS Azithromycin 500 mg IV daily WITH OR WITHOUT*: Vancomycin	For severe PCN allergy: Vancomycin PLUS one of: Levofloxacin 750 mg IV daily OR Moxifloxacin 400 mg IV daily	MRSA risk factors: prior influenza, presence cavitary disease, empyema. Consider influenza testing and treatment with oseltamivir. If no microbiologic confirmation of MRSA then discontinue vancomycin. See HCAP for risk factors for infection with Pseudomonas aeruginosa.
Healthcare –associated pneumonia (HCAP): acquired in long-term care facility where antimicrobials used or Pseudomonas risk factors (see Comments)	S.aureus S.pneumoniae H.influenzae  Antibiotic sensitive enteric gram negative bacilli: E. coli Enterobacter aerogenes Klebsiella pneumoniae Proteus mirabilis Serratia marcesans P. aeruginosa (if risk factors present)	Hemodynamically stable & no Pseudomonas risk factors Vancomycin PLUS one of: Ertapenem 1 g IV daily WITH OR WITHOUT one of*: Doxycycline 100 mg IV/PO BID OR Levofloxacin 750 mg IV/PO daily Hemodynamically unstable or Pseudomonas risk factors Vancomycin PLUS one of: Piperacillin/tazobactamID-R: SFGH 4.5 g IV q6h OR CefepimeID-R: SFGH VASF 2 g IV q8h-q12h WITH OR WITHOUT*: Azithromycin 500 mg IV daily	For severe PCN allergy: Vancomycin PLUS one of: AztreonamID-R: SFGH 2 g IV q8h WITH OR WITHOUT one of*: Doxycycline 100 mg IV/PO BID OR Azithromycin 500 mg IV daily		Pseudomonas risk factors include: structural lung disease, repeated exacerbations of severe COPD leading to frequent steroid and/or antibiotic use, recent mechanical ventilation, recent prior exposure to broad-spectrum antibiotics Avoid using levofloxacin if the patient has recently been treated with a fluoroquinolone. For patients admitted from the community with HCAP and not treated with levofloxacin, consider  adding atypical coverage with doxycycline (floor patients) or azithromycin (ICU patients).
Hospital-acquired pneumonia	EARLY ONSET including ventilator-associated or less than 5 days of hospitalization, no risk factors for drug-resistant organisms*	S. aureus S.pneumoniae H.influenzae  Antibiotic sensitive enteric gram negative bacilli: E. coli Enterobacter aerogenes Klebsiella pneumoniae Proteus mirabilis Serratia marcesans	Vancomycin PLUS one of Levofloxacin 750 mg IV daily OR Ertapenem 1 g IV daily		Risk factors include recent antibiotic exposure (within 30 days). Consider influenza testing and treatment with oseltamivir when influenza is known to be circulating.
	LATE ONSET including ventilator-associated OR ≥ 5 days of hospitalization or risk factors for resistant organisms*	E. coli Enterobacter aerogenes P. aeruginosa Klebsiella pneumoniae 'S. aureus'	Vancomycin PLUS one of: Piperacillin/tazobactam 4.5 g IV q6h   OR Cefepime 2 g IV q8-12h Alternatively: Vancomycin PLUS Meropenem 1-2 g IV q8h**	For severe PCN allergy: Vancomycin2 PLUS Aztreonam 2 g IV q8h WITH OR WITHOUT***: Tobramycin	**Consider use in patients with current or recent use (< 7 days) of piperacillin/tazobactam or cefepime and in patients with recent infection with multidrug resistant gram-negative bacteria. ***Weigh risks and benefits of adding aminoglycoside for critical illness, immunocompromise, or history of infection or colonization with drug-resistant Gram-negative rods.

'Septic Shock' Community onest, no recent healthcare exposure	Enterobacteriaceae S. aureus Streptococci spp.	Vancomycin PLUS one of: Piperacillin/ TazobactamID-R: SFGH 4.5 g IV q8h OR 'Ertapenem' 1 g IV daily	For severe PCN allergy: Vancomycin PLUS Metronidazole 500 mg IV/PO q8h PLUS one of AztreonamID-R: SFGH 2 g IV q8h OR Tobramycin
Healthcare-associated and/or previous antibiotic therapy	Enterobacteriaceae S. aureus Streptococci spp. P. aeruginosa	Vancomycin PLUS Piperacillin/ Tazobactam 4.5 g IV q6h OR Cefepime 2 g IV q8h	For severe PCN allergy: Vancomycin PLUS Metronidazole 500 mg IV q8h AND Aztreonam 2 g IV q8h WITH OR WITHOUT: Tobramycin	For patients with neutropenia, organ transplant, severe hepatic failure, or current/recent (<7 days) piperacillin/tazobactam or cefepime: Vancomycin Plus Meropenem 1-2 g IV q8h

'Abscess'	'S.aureus'	Vancomycin	Empirical Gram-negative and/or anaerobic coverage is not routinely indicated. Incision and drainage is primary therapy for abscesses. After incision and drainage and once patient is stable, switch to oral antibiotics based on culture and susceptibility results.
'Cellulitis'	Group A streptococci Other beta-hemolytic streptococci S.aureus	Vancomycin Alternatively: Cefazolin 1 g IV q8h if patient is stable and cellulitis is not associated with an abscess or other purulent focus of infection	Empirical Gram-negative and/or anaerobic coverage is not routinely indicated.
Necrotizing fasciitis or suspected deep tissue extension	Group A streptococci S. aureus Anaerobes Gram-negative rods	Vancomycin PLUS ONE OF: Piperacillin/tazobactam 4.5 g IV q6-8h OR Ertapenem 1 g IV daily ALL WITH: Clindamycin600 – 900 mg IV q8h  Alternatively if infection is health-care associated: Vancomycin PLUS Meropenem1-2 g IV q8h PLUS Clindamycin600-900 mg IV q8h	For severe PCN allergy: Vancomycin PLUS AztreonamID-R: SFGH 2 g IV q8h PLUS Clindamycin ID-R: VASF 600-900 mg IV q8h Clindamycin added for anti-toxin properties. Limited data support use for infections caused by Group A streptococci and Clostridium perfringens. Discontinue clindamycin once adequate surgical debridement is achieved.