Risk Factors for Piperacillin/Tazobactam Resistance in Extended-Spectrum Beta-Lactamase (ESBL) Producing Organisms

This is chart review at UPMC. NO human subject interaction will occur.

Inclusion Criteria:

- Clinical information is collected by chart review of "case" and "control" patients.

- A "case A" patient is defined as follows: One or more clinical cultures are positive
for an ESBL producing bacteria and the organism is piperacillin/tazobactam resistant.

- A "case B" patient is defined as follows: One or more clinical cultures are positive
for an ESBL producing bacteria and the organism is piperacillin/tazobactam
susceptible.

- Additionally, 1 control patient in the hospital at the same time as the case patients
will be randomly selected for each case and are not in either case group.

Exclusion Criteria:

- Patients < 18 years of age