Diagnosis	Common  Pathogens		Drug(s) of  First Choice1		Alternative  Drug(s)1		Comments
BRONCHITIS
Acute Bronchitis		Viral	No drug therapy required	No drug therapy required		In general, antibiotics are NOT useful in acute bronchitis.  Purulent sputum alone is not an indication for antibiotics.
Acute bacterial exacerbation of chronic bronchitis  (COPD)		S. pneumoniae  H. influenzae   Moraxella catarrhalis	Doxycycline 100 mg PO BID x 10 days	Trimethoprim/Sulfamethoxazole  One DS tablet PO BID x 10 days		The value of antibiotics in acute exacerbations of chronic bronchitis is controversial.   Sputum gram stain can be useful.  Absence of organism on sputum gram stain may be useful in excluding bacterial etiology.  Encourage patient to stop smoking.  Pneumococcal and influenza vaccines should be administered.

 
 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Alternative  Drug(s)1	Comments
CELLULITIS
Extremities	Group A streptococci; secondarily Staph. aureus (uncommon but difficult to exclude)	Dicloxacillin 500 mg PO QID x 10 days, then reassess.  or  Cephalexin 500 mg PO QID x 10 days, then reassess.	If mild PCN allergy2:  Cephalexin 500 mg PO QID x 10 days, then reassess.  If severe PCN allergic2:  Clindamycin 300 mg PO TID x 10 days, then reassess.	For lower extremity cellulitis: Look for, and treat, tinea pedis.

 

 

Diagnosis	Common  Pathogens		Drug(s) of  First Choice1			Alternative  Drug(s)1		Comments
COMMUNITY ACQUIRED PNEUMONIA (CAP)
Adult   With or without co-morbid conditions		S. pneumoniae  M. pneumoniae  C. pneumoniae  Respiratory viruses  Legionella spp.   C. psittaci  H. influenzae (if patient has co-morbidity)		Doxycycline 100 mg PO BID for   7-10 days, then reassess.  or   Erythromycin 500 mg PO QID for 7-10 days, then reassess.  or  Azithromycin 500 mg PO QD x 1 day; then 250 mg PO QD x 4 days.  or  Clarithromycin 500 mg PO BID for 7-10 days, then reassess.	Levofloxacin 500 mg PO QD		The value of levofloxacin in the management of CAP is in confirmed, not presumed, infection with high-level penicillin-resistant pneumococcus.  Azithromycin or clarithromycin may offer improved activity over erythromycin against H. influenzae, however, no better than doxycycline.  Doxycycline is better tolerated than erythromycin.  Erythromycin requires more frequent dosing than other macrolides.  If gram (+) diplococci predominate on gram stain, use amoxicillin.   Careful follow-up highly recommended.

 

 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Alternative  Drug(s)1	Comments
DIVERTICULITIS
No signs of bowel perforation.   If bowel perforation, see Peritonitis on Inpatient Antibiotic Guidelines	Enterobacteriaceae  Bacteroides fragilis  Enterococci	Amoxicillin/Clavulanate   875/125 PO BID     Duration of treatment should be until patient is afebrile for 3-5 days	For PCN allergic patients2:  Fluoroquinolone  plus  Metronidazole 500mg PO TID  or  Trimethoprim/Sulfamethoxazole  One DS tablet PO BID   Plus  Metronidazole 500 mg PO TID   Duration of treatment should be until patient is afebrile for 3-5 days	Surgical evaluation and follow up is advised.

 
 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Alternative  Drug(s)1	Comments
FOLLICULITIS
	Staph. aureus  P. aeruginosa	Dicloxacillin   500mg PO QID x 3-5 days  or   Cephalexin   500mg PO QID x 3-5 days	For PCN allergic patients2:  Clindamycin   300mg PO TID x 3-5 days	Immunocompromised patients (i.e., HIV/AIDS) may require longer duration of therapy.

 
 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Alternative  Drug(s)1	Comments
FOOT ULCER (DIABETIC)
Previously untreated; limited in extent; no osteomyelitis	Staph. aureus  Strep. spp.  Other aerobic gram (+) cocci possible, less likely	Cephalexin 500 mg PO QID for 14 days	For PCN allergic patients2:  Clindamycin 300 mg PO TID for 14 days	Obtain x-ray if osteomyelitis is a consideration.

 

 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Comments
GASTROENTERITIS
Clinical Presentation  Dysenteric Diarrhea     Frequent, sometimes bloody, small-volume diarrhea.  Left, lower quadrant abdominal pain and cramping.  Patient may be febrile and toxic.	Shigella  Salmonella  Campylobacter  Yersinia  invasive E. coli  C. difficile  E. histolytica	Shigella ? Ciprofloxacin 500mg po bid x 3days.  Salmonella ? generally self-limiting, treatment may prolong carrier state.  Campylobacter ? self-limiting, treatment indicated if symptoms persist.   Erythromycin 500mg po qid x 5days or  Ciprofloxacin 500mg po bid x 5days.  Yersinia ? Ciprofloxacin 500mg po bid x 3days.  E. coli 0157:H7 ? no antimicrobial treatment recommended.  C. difficile ? Obtain history of recent antibiotic use and obtain stool toxin assay for C. difficile. Metronidazole 500mg PO tid x 10-14days.  Amebic colitis ? Consider treatment if history of travel to endemic area.	General Comments  Empiric therapy is generally indicated if patient is toxic appearing, elderly or immunocompromised. If empiric therapy is given, obtain culture and give fluoroquinolone x 3 days while awaiting cultures.  Stool cultures (including E. Coli 0157:H7 culture if bloody diarrhea) and C. difficile toxin are indicated.. Therapy is directed at isolated pathogen.  Replace fluids and electrolytes lost in the diarrheal process.  CDC recipe for volume replacement: _ tsp table salt, 1 tsp baking powder, 4 tbsp sugar, 1 cup orange juice, 1 liter clean water.  Antimotility agents may exacerbate illness, but may be useful if the patient is not toxic appearing, a pathogen other than C. difficile has been identified, and if appropriate antibiotic treatment (if indicated) has been initiated.   Strict handwashing is mandatory in all food preparation.
Nondysenteric Diarrhea  Large volume, nonbloody, watery diarrhea  Patient may have nausea, vomiting, and abdominal cramping	Viruses  Vibrio cholerae  Giardia  Enterotoxigenic E. coli  Enterotoxin-producing bacteria	Observation  Oral rehydration  Antimotility agents   If patient describes recent history of travel and/or ingestion of unfiltered water (e.g., camping), consider Giardia ? Metronidazole 250mg po tid x 5 days.	Generally, empiric therapy and stool cultures are not indicated. Most disease is self-limiting and can be treated with antimotility agents.   If patient fails to improve, cultures (-), and symptoms persist, obtain stool for O & P to rule out Giardia.  Check C. difficile toxin if recent history of antibiotic use or hospitalization.   Characteristics of viral disease: Watery diarrhea, nausea/vomiting present.   Cholera is a life-threatening, non-invasive diarrhea that requires therapy. Obtain travel history to determine if patient has been to an endemic area. Vibrio cholerae ? Ciprofloxacin 1gm po x1

 
 
 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Comments
Traveler’s diarrhea  Empiric Treatment while abroad	Toxigenic E. coli  Salmonella  Shigella  Campylobacter  Amebiasis	Ciprofloxacin 500 mg PO BID x 3-5 days  and   Loperamide 4mg PO x1; then 2mg after each loose stool, 16mg maximum/day.	Mild, self-limited cases can be treated with fluid and electrolyte repletion and bismuth subsalicylate.

 
 
 

Diagnosis	Common  Pathogens		Drug(s) of  First Choice1			Alternative  Drug(s)1		Comments
HERPES SIMPLEX VIRUS (HSV)
GENITAL HERPES
Acute and Recurrent  Episodes	HSV 2 = 70-90%  HSV 1 = 10-30%		Acyclovir 400 mg PO TID x 7-10 days			Valacyclovir 1 gram PO BID x 7-10 days		In HIV patients with documented acyclovir resistance, use foscarnet.  Acyclovir 400 mg PO TID has been shown to be equivalent to Acyclovir 200 mg PO 5 x daily.
Suppression for Frequent Recurrence	HSV 2 = 70-90%  HSV 1 = 10-30%		Acyclovir 400 mg PO BID x 7 days			Valacyclovir 500 mg PO BID		Consider suppressive therapy for patients experiencing greater than 3-4 episodes in 12 months.
FACIAL/ORAL HERPES
Recurrent episodes in immunocompetent patients		HSV 1  HSV 2		Penciclovir 1% cream q2h while awake for 4 days   or  Acyclovir 400 mg PO TID x 7 days			Either agent decreases time to healing by 1 day.   Selection of which agent is at the discretion of the prescriber.  Acyclovir 400 mg PO TID is equivalent to Acyclovir 200 mg PO 5 x daily.

 
 
 

Diagnosis	Common  Pathogens		Drug(s) of  First Choice1			Alternative  Drug(s)1	Comments
HERPES ZOSTER
Immunocompetent  (Shingles/Zoster)		Varicella Zoster Virus		Acyclovir 800 mg PO QID x 5 days	Valacyclovir 1 gram PO TID x 7 days  or  Famciclovir 500 mg PO TID x 7 days			Treatment initiated within 48 hours of symptom onset may shorten duration of illness in immunocompetent patients.   In patients 65 years old administration of concomitant corticosteroids may improve quality of life.
Immunocompromised  (Lymphoma, HIV infection, etc)  Not severe (1 dermatome)  If Severe ( 1 dermatome) ? see Inpatient Antibiotic Guidelines ?IV regimen recommended		Varicella Zoster Virus		Acyclovir 800 mg PO   5 times daily x 7 days	Valacyclovir 1 gram PO TID x 7 days  or  Famciclovir 500 mg PO TID x 7 days			Therapy must begin within 72 hours of symptom onset. Treatment for 10 days may decrease the duration of post-herpetic neuralgia.
Primary Infection in Adults (Chicken Pox)		Varicella Zoster Virus		Acyclovir 800 mg PO QID x 5 days				Initiate therapy within 24 hours of onset of rash.   Consider vaccination for non-immune household contacts.  No clinical data available at this time, however valacyclovir should be equally effective.

 
 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Alternative  Drug(s)1	Comments
MASTITIS
Postpartum	Staph. aureus	Dicloxacillin 500 mg PO QID x 10 days  or  Cephalexin 500mg PO QID x 10 days	For mild PCN allergy2:  Cephalexin 500mg PO QID x 10 days  For severe PCN allergy2:   Clindamycin 300 mg PO TID x 10 days	If no abscess, increased frequency of nursing may hasten response.  If abscess, I & D required; discontinue nursing.

 
 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1		Alternative  Drug(s)1	Comments
OTITIS MEDIA
Acute w/ effusion	Strep. pneumoniae (25-50%)  H. influenzae (15-30%)  M. catarrhalis(3-20%)  Group A Strep. (2%)		Amoxicillin 500 mg po q8h   x 5-7 days	For severe penicillin allergy2:   Trimethoprim/Sulfamethoxazole DS, One PO BID  or   Doxycycline 100mg PO BID  Therapy continued for 5-7 days	Amoxicillin/clavulanic acid not indicated as initial therapy of acute otitis.   For recurrent prolonged otitis consider ENT referral.

 
 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Alternative  Drug(s)1	Comments
PHARYNGITIS/TONSILLITIS
Pharyngitis	Viral  Streptococcus (5-20%)	Penicillin VK 500 mg po QID   x 10 days	For PCN allergic patients2:  Erythromycin 250-500 mg po QID  x 10 days  or  Doxycycline 100 mg PO BID x 10 days	Treatment with PCN prevents Group A streptococci-associated rheumatic fever.   Treat documented Group A streptococcal infection confirmed by rapid strep. antigen test or culture.

 
 

Diagnosis	Common  Pathogens			Drug(s) of  First Choice1		Alternative  Drug(s)1		Comments
PROSTATITIS
Acute		Enterobacteriaceae (E. coli)  Enterococci	Fluoroquinolone x 21 days				30% of E. coli isolates are resistant to Trimethoprim/Sulfamethoxazole.  Consider sexually transmitted disease treatment (Gonococcus or C. trachomatis) for appropriate patient populations.  Antibiotic penetration in the acute inflammatory state is adequate for the use of most antibiotics. Choice of agent should be based on sensitivities.
Chronic		Enterobacteriaceae (E. coli)  Enterococci	Fluoruoquinolone x 2-3 months  or  Doxycycline 100mg PO BID x 2-3 months (if gram positive cocci, especially Enterococcus)				30% of E. coli isolates are resistant to Trimethoprim/Sulfamethoxazole.  Consider sexually transmitted disease treatment (Gonococcus or C. trachomatis) for appropriate patient populations.  Few drugs penetrate non-inflamed prostate. Fluoroquinolone, trimethoprim/sulfamethoxazole and doxycycline adequately penetrate in non-inflamed state.  Consider urologic evaluation.
PYELONEPHRITIS
	Enterobacteriaceae (E. coli)  Enterococci			Fluoroquinolone x 14-21 days  or  Cephalexin 500 mg PO QID x 14-21 days				For patients not tolerating oral therapy, may initiate therapy with single dose parenteral ceftriaxone or aminoglycoside while awaiting culture.

 
 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Alternative  Drug(s)1	Comments
SEXUALLY TRANSMITTED DISEASES (STD’S)
Syphilis     Early     Latent	T. pallidum	Benzathine penicillin G 2.4 MU IM X 1 dose2  Benzathine penicillin G 2.4 MU IM Q week X 3 doses2	Doxycycline 100 mg PO BID X 2 weeks	Sexual partners must be treated.
Gonorrhea	N. gonorrhea	Cefixime 400 mg PO X 1 dose  or  Fluoroquinolone (ciprofloxacin 500 mg or ofloxacin 400 mg) PO X 1 dose     Each of the above courses should be followed by azithromycin 1.0 gm PO X 1 or doxycycline 100 mg BID PO X 7 days or erythromycin 500 mg QID PO X 7 days	Ceftriaxone 125 mg IM X 1 dose  Considering high frequency of Neisseria coinfection with Chamydia, concomitant therapy with azithromycin, doxycycline, or erythromycin must be administered	All cases of syphilis and Gonococcus must be reported to the San Francisco Public Health Department at 206-8524.  Sexual partners must be treated.   Consider azithromycin for non-compliant patients where directly observed therapy is necessary.   Pharyngeal Gonococcus must be treated with a fluoroquinolone or ceftriaxone.

 
 
 

DiagnosisAlternative  Drug(s)1	Comments
SINUSITIS, ACUTE
	Viruses  Strep. pneumoniae  H. influenzae  M. catarrhalis	Amoxicillin 500 mg po q8h   x 5-7 days  or  Trimethoprim/Sulfamethoxazole DS One PO BID x 5-7 days	For severe PCN allergy2:  Doxycycline 100mg PO BID x 5-7 days		Consider treatment only in presence of fever, purulence or bloody discharge suggesting bacterial etiology.
SINUSITIS, CHRONIC
	Strep. pneumoniae  H. influenzae  M. catarrhalis  Viruses  Anaerobes  Staph. aureus  Enterobacteriacae	Amoxicillin Clavulanate   875/125 PO BID x 10 days	For PCN allergic patients2:  Clindamycin 300 mg PO TID  With Fluoroquinolone x 10 days		Antibiotics usually not effective.  Consider otolaryngology consult to rule out anatomic abnormality.  If acute exacerbation, treat as acute sinusitis.  HIV positive patients may need a 2-3 week course.

 
 
 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Alternative  Drug(s)1	Comments
URINARY TRACT INFECTION (UTI)
Uncomplicated	Enterobacteriaceae (E. coli)  Enterococci  Staph. saprophyticus (Coagulase negative staphylococcus) (4%)	Fluoroquinolone x 3 days (women) 7-10 days (men)  Or  Nitrofurantoin 50-100 mg QID x 7 days (women) 7-10 days (men). Do not use in renal failure	Trimethoprim/Sulfamethoxazole DS One PO BID x 3 days (women) 7-10 days(men)	30% of E. coli isolates are resistant to Trimethoprim/Sulfamethoxazole  For urethritis see entry on Sexually Transmitted Diseases.  For prostatitis see Prostatitis entry.  Rule out anatomic abnormality in men.
Women  Recurrent  (3 or more episodes/year)	Enterobacteriaceae (E. coli)  Staph. saprophyticus (Coagulase negative staphylococcus) (4%)  Enterococci	Prophylaxis:  Nitrofurantoin 50 mg PO QD	Prophylaxis:  Trimethoprim/Sulfamethoxazole Single Strength One PO QD or QOD	Previous culture results should guide choice of prophylactic agents.
Men   Recurrent				Consider urologic evaluation

 
 

Diagnosis	Common  Pathogens		Drug(s) of  First Choice1		Alternative  Drug(s)1			Comments
TUBERCULOSIS
Treatment		Mycobacterium tuberculosis		Isoniazid (INH) 300 mg PO daily   x 6 months  plus  Rifampin 600 mg PO daily  x 6 months  plus  Pyrazinamide (PZA) 25 mg/kg PO daily x 2months  plus  Ethambutol 15 mg/kg PO daily until Isoniazid or Rifampin sensitivity established  plus  Pyridoxine (Vitamin B-6) 50 mg PO daily for 6 months			All cases of tuberculosis must be reported. Call the SF Department of Public Health at 206-8524.  Obtain baseline LFT’s on all patients. Additional LFT’s advised if liver disease present.   If organism pansensitive, discontinue ethambutol. Continue PZA for a total of 2 months. Continue Isoniazid and Rifampin for a total of 6 months  If complicated, drug-resistant case, send to SFGH.  If immunocompromised or extra-pulmonary disease, admit for inpatient treatment.   Consider numerous drug/drug interactions in patients on antiretroviral agents.  Directly observed therapy has been shown to reduce treatment failures.   For seroconverters consult ATS Guidelines.

 
 
 

Diagnosis	Common  Pathogens	Drug(s) of  First Choice1	Alternative  Drug(s)1	Comments
VAGINITIS
Fungal	Candida albicans	Butoconazole (2% cream) or clotrimazole 200 mg vaginal tablet or terconazole (0.8% cream or 80 mg suppository) or miconazole (200mg suppository) once daily X 3 days     Fluconazole 150 mg PO X 1 dose	Single dose topical therapies are available but are less effective.  Seven day courses of therapy are not superior to 3 day regimens
Protozoan	Trichomonas vaginalis	Metronidazole 2 gm PO X 1 dose        Metronidazole 500 mg BID PO X 7 days	Alternative regimens are experimental and less effective than metronidazole	In treatment failures to metronidazole, retreat with metronidazole 500 mg PO BID x 7 days. For repeated failures, administer metronidazole 2.0 gm QD PO for 3-5 days
Bacterial	Gardnerella, other anaerobes	Metronidazole 2 gm PO X 1 dose     Metronidazole 500 mg BID PO X 7 days	Clindamycin vaginal cream QD X 7 days  Metronidazole vaginal gel BID X 7 days  Clindamycin 300 mg BID PO X 7 days	A single 2 gm dose of metronidazole is slightly less efficacious compared to the 7 day course of therapy. However, single dose therapy may be preferable due to compliance.

 
Last Updated 6/17/99