Category	Diagnostic criteria	Principal pathogens	First-line therapy	Comments
Acute uncomplicated cystitis	Urinalysis for pyuria and hematuria (culture not required)	Escherichia coli Staphylococcus saprophyticus Proteus mirabilis Klebsiella pneumoniae	TMP-SMX DS (Bactrim, Septra) Trimethoprim (Proloprim) Ciprofloxacin (Cipro) Ofloxacin (Floxin)	Three-day course is best Quinolones may be used in areas of TMP-SMX resistance or in patients who cannot tolerate TMP-SMX
Recurrent cystitis in young women	Symptoms and a urine culture with a bacterial count of more than100 CFU per mL of urine	Same as for acute uncomplicated cystitis	If the patient has more than three cystitis episodes per year, treat prophylactically with postcoital, patient-directed* or continuous daily therapy (see text)	Repeat therapy for seven to10 days based on culture results and then use prophylactic therapy
Acute cystitis in young men	Urine culture with a bacterial count of 1,000 to 10,000 CFU per mL of urine	Same as for acute uncomplicated cystitis	Same as for acute uncomplicated cystitis	Treat for seven to 10 days
Acute uncomplicated pyelonephritis	Urine culture with a bacterial count of100,000 CFU per mL of urine	Same as for acute uncomplicated cystitis	If gram-negative organism, oral fluoroquinolone	Switch from IV to oral administration when the patient is able to take medication by mouth; complete a 14-day course
			If gram-positive organism, amoxicillin
			If parenteral administration is required, ceftriaxone (Rocephin) or a fluoroquinolone
			If Enterococcus species, add oral or IV amoxicillin
Complicated urinary tract infection	Urine culture with a bacterial count of more than 10,000 CFU per mL of urine	E. coli K. pneumoniae P. mirabilis Enterococcus species Pseudomonas aeruginosa	If gram-negative organism, oral fluoroquinolone If Enterococcus species, ampicillin or amoxicillin with or without gentamicin(Garamycin)	Treat for 10 to 14 days
Asymptomatic bacteriuria in pregnancy	Urine culture with a bacterial count of more than 10,000 CFU per mL of urine	Same as for acute uncomplicated cystitis	Amoxicillin Nitrofurantoin (Macrodantin) Cephalexin (Keflex)	Avoid tetracyclines and fluoroquinolones Treat for three to seven days
Catheter-associated urinary tract	Symptoms and a urine culture with a bacterial count of more than100 CFU per mL of urine	Depends on duration of catheterization	If gram-negative organism, a fluoroquinolone	Remove catheter if possible, and treat for seven to 10 days
			If gram-positive organism, ampicillin or amoxicillin plus gentamicin	For patients with long-term catheters and symptoms, treat for five to seven days