P-1146. Environmental Surfaces in Healthy Households as Reservoirs of Extended-Spectrum Cephalosporin-Resistant Enterobacterales in the Community

Abstract Background Community-acquired extended-spectrum cephalosporin resistant (ESCr)-Enterobacterales (E) are increasing in healthy populations, yet the sources of acquisition are unknown. We assessed household (HH) environmental surface samples (HS) in St. Louis, MO, to identify the surfaces most frequently contaminated with ESCr-E and the associated mechanisms of antibiotic resistance (AR). Figure 1. Enterobacterales within households. Methods From 139 HHs, samples from 21 HS and inguinal fold (IF) samples of healthy adults and children were cultured for bacteria. Families were recruited from outpatient pediatric settings. Bacterial identification and antibiotic susceptibility testing were conducted (Vitek®2, bioMérieux). Molecular characterization of ESCr-E was performed by PCR detection of beta-lactamase (bla) and plasmid-mediated quinolone resistance (PMQR) genes. Whole genome sequencing (WGS) was performed on select HH with > 1 colonized HS to evaluate for genetic relatedness, plasmids, and AR genes. A HH cluster was defined as < 15 single nucleotide polymorphism differences between 2 isolates. Figure 2. ESCR Enterobacterales by genera Results Of 581 IF and 2801 HS, the majority harbored bacteria (IF, 97-100% and HS, 79-100%) and gram-negative bacteria, (IF, 72-80% and HS, 75-87%). IF colonization with Enterobacterales was ∼23% and ranged from 7-60% on HS; The most common ESCr-E genera were Enterobacter (79%), Pantoea (10%), and Klebsiella (7%). ESCr-E were found in 2% of IF. HS most notably colonized with ESCr-E were the kitchen sink faucet (9%), oven door handle (4%), sofa (4%), bathroom sink faucet (3%) and bed sheets (3%), (Figures 1-3). ESBL-E were recovered from ∼2% of HHs. MDR-E (> 3 antibiotic classes) were found in 4% of HHs. WGS of 20 E. cloacae from 4 HHs revealed within HH clusters (Figure 4). Of interest, we found that among E. cloacae, 10/20 (50%) contained AR plasmids (ex. IncFI, IncFII, IncX5, IncHI2, Col440I); bla, other AR (ex. PMQR, aminoglycoside, sulfa, fosfomycin) and virulence genes were detected in E. cloacae in all HHs. We also found related E. cloacae strains in 2 HHs (ST108), indicating local strains circulating potentially related to a common exposure. Figure 3. AR Enterobacterales by surface. Conclusion ESCr-E are present in healthy household environments. Future directions will be to identify candidate clinical and epidemiological features linked with ESCr-E HH colonization. Figure 4. Genetic relatedness among household Enterobacter cloacae Disclosures Ahmed Babiker, MBBS, Beckman Coulter Inc.: Advisor/Consultant