The purposes of this study are:

1. To estimate the prevalence of extended spectrum β-lactamase (ESBL) and/or AmpC among Enterobacteriaceae which cause community-onset urinary tract infections (UTIs)
2. To collect the background, risk factors and clinical outcome of patients with community-acquired uropathogenic condition related to Enterobacteriaceae (both ESBL, AmpC- and non ESBL and/or AmpC producing) after receive different antibiotic regimens.
3. To develop a scoring system to early identify patients at risk of being infected with ESBL- and/or AmpC-producing Enterobacteriaceae by comparing the risk factors for community-onset UTIs caused by ESBL- and/or AmpC-positive against non ESBL -and/or AmpC Enterobacteriaceae
4. To demonstrate the efficacy and safety of ertapenem for the empiric treatment of community-onset UTIs in patients at risk for ESBL- and/or AmpC-producing organism.

The study hypothesis (i) Patients infected with community-acquired uropathogenic ESBL- and/or AmpC-producing Enterobacteriaceae who receive regimens other than carbapenems have a worse outcome.

(ii) There are certain risk factors predicting the acquisition of community-onset UTIs caused by ESBL- and/or AmpC-producing Enterobacteriaceae.

(iii) The use of ertapenem is an effective and safe empirical therapy compared with other agents for community-onset UTIs caused by ESBL- and/or AmpC-producing Enterobacteriaceae.

Inclusion Criteria:

• Adult patients who admitted to the Taipei Veterans General Hospital with the diagnosis of community-onset UTI caused by Enterobacteriaceae will be eligible for inclusion in this study if hospitalization for parental antimicrobial therapy is required

Exclusion Criteria:

• pregnancy or lactation in women,
• history of serious allergy or intolerance to study drug therapy (patients with a history of mild rash to β-lactams could be enrolled),
• complete obstruction of the urinary tract,
• peri-nephritic or intrarenal abscess, prostatitis, any rapidly progressive disease or terminal illness,
• immuno-compromising illness or immuno suppression therapy, the need for concomitant antimicrobials in addition to study therapy,
• a baseline pathogen resistant to study drug,
• treatment with a systemic antimicrobial agent for >24 h within 72 h prior to enrolment, or absolute neutrophil count <1000/mm3.
• Men with a history or physical findings suggestive of acute or chronic prostatitis will also excluded.

Adult patients who admitted to the Taipei Veterans General Hospital, a 2900-bed tertiary-care teaching hospital located in Taipei, Taiwan, with the diagnosis of community-onset UTI caused by Enterobacteriaceae