Carbapenem-resistant bacteria have been present in Orange County for over a decade; several, such as carbapenem-resistant E coli, Klebsiella, Enterobacter, and Pseudomonas aeruginosa, are endemic in Southern California, including Orange County. Once a bacteria type becomes endemic in a community, many patients will be unknowingly colonized, making targeted public response to the known colonized cases less effective. To make best use of limited public health resources, OCHCA’s particular focus is responding to organisms such as CRAB that are newly emerging in the county, before they become endemic.
As with other carbapenem-resistant organisms, patients with chronic medical conditions are at highest risk for CRAB infection. CRAB infections and outbreaks are most often identified in healthcare settings, including acute care hospitals, long term acute care hospitals, and skilled nursing facilities. CRAB can be found in the healthcare environment (e.g., water, environmental surfaces, medical devices) and on a person’s skin. It can be transmitted from the environment to persons or from person-to-person in healthcare settings.
Over 90% of CRAB isolates tested in Orange County in 2021 produce OXA-23 carbapenemase. Thus, any CRAB organism should be presumed to be carbapenemase-producing if no carbapenemase testing is performed. In addition, carbapenemase testing may need to be performed by a referral lab, leading to delays in reporting of results; these cases should be treated as CP-CRAB pending the results of testing.