California Antibiogram Project 2007

The goals of the California Antibiogram Project (CAL-AP) are to:

• track and monitor resistance trends of bacteria of public health importance throughout California;
• raise awareness of resistance problems, and
• identify opportunities to reduce inappropriate antibiotic usage.

The CAL-AP is a collaboration of 79 hospitals situated throughout the state, including academic, private, community, and health maintenance organization institutions, who have contributed their cumulative antimicrobial susceptibility test data.  Antimicrobial susceptibility data is routinely collected by many hospitals on a regular basis and compiled into a cumulative antibiogram, or table that lists commonly encountered species and the percentages of each that are susceptible to various antimicrobial agents that might be used in treating infections caused by those species.  Each facility’s cumulative antibiogram can be used as a guide for selecting empiric therapy for initial infections and to monitor resistance trends.  The compilation of aggregated antibiogram data is a simple and relatively efficient way to monitor antimicrobial resistance on a large scale.  CAL-AP hospitals who have contributed their antibiogram data to this project include:

 * Best estimate of numbers of licensed beds based on 2009 available information, including from the Office of Statewide Health Planning and Development (OSHPD; available at URL:  http://www.oshpd.ca.gov/HID/DataFlow/index.html) and the California Hospital Association (URL: www.calhealth.org/public/mem/documents/MemberHosp0209.pdf).  Note that the bed size data are provided to give an estimate of the relative patient populations served by these hospitals, but the relationships between hospital bed size and outpatient population size are uncertain.

All participating hospitals were encouraged to contribute data collected and analyzed according to Clinical and Laboratory Standards Institute (CLSI) performance standards, including elimination of duplicate test results from the same patient.  However, there were several factors that could not be controlled and which could impact the cumulative antibiogram data provided from each facility as well as the aggregate regional and statewide cumulative antibiogram reports. These include culturing practices, antimicrobial susceptibility testing policies, and patient population served. In addition, not all agents for which data were requested from participating laboratories were tested in each laboratory and not all agents were tested against each isolate. Consequently, when examining the aggregate data provided herein, it is important to examine each agent individually and not to compare one agent to another.