LAUSR

Abstract Background Gene-based screening is a tool to detect and track multi-drug-resistant organisms (MDROs) in hospitalized patients. MDRO acquisition and colonization during the duration of a hospital stay and their persistence over time are not well described. Methods A peri-anal swab was collected within 48 hours of admission from patients on medical wards and the MICU at the Washington DC VA Medical Center and repeat swabs were obtained day 7 and 14 on patients consenting to participate. Clinical and laboratory data from admission to 12mo post discharge was reviewed. Genes associated with VRE (VanA), ESBL (CTX-M), carbapenase-producing organisms or CPOs (OXA-23, OXA-51) and CREs (KPC,NDM,VIM, IMP, OXA-48) were tested on swabs by the Acuitas-MDRO Test (OpGen, Inc.). Results Between July 2015 and August 2016, 565 hospitalized patients were screened with 210 swabs collected from 182 subjects. One swab was nonevaluable. Subjects had a mean age 67.5 ± 12.0 years (26–94 years, 38% ≥70 years) and 39% received empiric antibiotics at admission. Subjects were hospitalized for 1037 cumulative bed-days (1–81 days) with median LOS of 3 days; 84% (152/182) had a stay of a week or less. Among those who remained hospitalized long enough for serial testing, 45% were willing or able to provide >1 swab. Those with >1 swab were significantly older (+4.9 years, P = 0.03), more likely to have to have been admitted for an infectious diagnosis (48% vs. 24%, P = 0.02). All subjects negative for MDRO genes on admission with >1 swab remained negative on serial sampling. Sixteen subjects (8.8%) had one or more genes present on screening and all three with >1 swab had persistence of that gene on repeat sampling. Genes harbored included CTX-M (4.4%), VanA (4.4%), OXA-51(0.6%), KPC (0.6%). Conclusion The rate of occult MDRO colonization was low in our predominately elderly hospitalized patients. The majority of consenting participants were discharged before swabs could be repeated. Serial sampling revealed that results of swabs persisted over time in the same subject despite treatments received during hospitalization, including exposures to antibiotics. The identification of occult MDRO carriage during a hospitalization, even when obtained after admission, may have utility in guiding treatment for providers. Disclosures All authors: No reported disclosures.