Distribution and Antibiotic Resistance Profiles of Salmonella enterica in Rural Areas of North Carolina After Hurricane Florence in 2018

In this study, water samples were analyzed from a rural area of North Carolina after Hurricane Florence in 2018 and the distribution of the ttrC virulence gene of Salmonella enterica were investigated. We also examined the distribution of culturable S. enterica and determined their antibiotic resistance profiles. Antibiotic resistance genes (ARGs) in the classes of aminoglycoside, beta‐lactam, and macrolide‐lincosamide‐streptogramin B (MLSB) were targeted in this study. The ttrC gene was detected in 23 out of 25 locations. There was a wider and higher range of the ttrC gene in flooded water versus unflooded water samples (0–2.12 × 105 copies/L vs. 0–4.86 × 104 copies/L). Culturable S. enterica was isolated from 10 of 25 sampling locations, which was less prevalent than the distribution of the ttrC gene. The antibiotic resistance profiles were not distinct among the S. enterica isolates. The aminoglycoside resistance gene aac(6')‐Iy had the highest relative abundance (around 0.05 copies/16S rRNA gene copy in all isolates) among all ARGs. These findings suggested that the 2018 flooding event led to higher copy numbers of the ttrC genes of S. enterica in some flooded water bodies compared to those in unflooded water bodies. The high ARG level and similar ARG profiles were observed in all S. enterica isolates from both flooded and unflooded samples, suggesting that the antibiotic resistance was prevalent in S. enterica within this region, regardless of flooding. Figure S1. The elevations of the 25 sampling locations. Table S1. The GPS Information of the 25 Sampling Locations. Table S2. The List of the Primers Targeted and Validated in This Study. [File Name: Supplementary Table 2] Table S3. The High-throughput qPCR Condition for ARGs Detection. [File Name: Supplementary Table 3] Table S4. The Positive ARGs in the 32 S. enterica Isolates. [File Name: Supplementary Table 4] Table S5. The Relative Abundances of the 30 Quantifiable ARGs in the 32 S. enterica Isolates. [File Name: Supplementary Table 5