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A Comprehensive, Intensive Patient Surveillance Program for Carbapenemase-Producing Bacteria at the National Institutes of Health Clinical Center

Year: 2016

Type: article

Abstract: Background. Carbapenemase-producing organisms (CPO) are important nosocomial pathogens that spread from colonized patients. After a 2011 outbreak of CPO at the NIH Clinical Center, the hospital prioritized early identification and isolation of CPO carriers. Admission perirectal surveillance cultures were added in September 2013 to an existing surveillance program. We describe our experience during the first 2.5 years of CPO admission surveillance. Methods. From September 2013 to April 2016, perirectal swabs were automatically ordered for all patients on admission to non-behavioral health wards. Manual orders were placed for swabs twice weekly in the ICU, weekly in other high-risk wards, and monthly for point prevalence throughout the hospital. Patients hospitalized in the United States in the previous week or abroad in the previous 6 months met Centers for Disease Control and Prevention (CDC) criteria for higher risk of colonization, and were empirically isolated pending 2 perirectal swabs. Swabs (n = 18,487) were cultured onto chromogenic media. All Gram-negative bacilli (GNB) were identified by MALDI-TOF MS and screened by PCR for blaKPC/blaNDM (blaOXA48 was tested for specific cases). Selected GNB were subject to susceptibility testing. Whole-genome sequencing was used for epidemiological strain typing of CPOs. Some perirectal swabs were tested directly by blaKPC PCR (n = 770) in response to a known blaKPC carrier or when selective media was unavailable. Results. Among 26,495 orders for surveillance swabs, 19,257 swabs were collected from 6,440 patients, a 73% compliance rate. Of 21 CPO-colonized patients identified from September 2013 through April 2016, 11 were identified via admission surveillance, 4 in point prevalence surveys, 4 from high-risk ward surveillance, and 2 from clinical cultures. Sequencing demonstrated no relatedness among CPO isolates. Although only 0.18% of patients sampled on admission were found to be colonized with CPO, those meeting CDC high-risk criteria were 38 times as likely to be colonized on admission. Conclusion. At a hospital with a geographically broad referral base, more than half of CPO-colonized patients were identified on admission. Despite aggressive admission surveillance, some carriers were identified well after admission. Every CPO carrier who is identified and isolated early represents a potentially averted reservoir for nosocomial transmission. Disclosures. All authors: No reported disclosures.

Source: Open Forum Infectious Diseases

DOI: 10.1093/ofid/ofw172.205