Emergence and Evolution of High-Level Cephalosporin-Resistant Salmonella Goldcoast in Northern Taiwan

Abstract

Background Nontyphoidal Salmonella (NTS) is an important foodborne pathogen worldwide. We investigated a 2018 outbreak of highly antimicrobial-resistant Salmonella enterica serotype Goldcoast in northern Taiwan. Methods We collected 30 clinical isolates and 2 meat isolates from this outbreak in New Taipei and Taoyuan, Taiwan in 2018. The clinical manifestations and the treatment of the patients were reviewed. To trace the source, we examined NTS isolated from food samples collected from the markets in northern Taiwan. All of the isolates along with an additional human isolate from China were sequenced and compared with the sequences of Salmonella Goldcoast reported by other countries. Results The outbreak involved 14 pediatric patients (<5 years old) and 16 adults (36 to 83 years old). Nine patients with invasive or severe disease required carbapenem treatment. The MIC90 of ceftriaxone and ciprofloxacin for the outbreak isolates was >256 μg/mL and 1 μg/mL, respectively, and a conjugative 278-kilobase plasmid harboring blaCTX-M-55 and qnrS1 contributed towards the resistance. Whole-genome sequencing revealed a clonal relationship among the outbreak isolates and the 2 collected from the retail meats. The outbreak clone was phylogenetically close to that of Salmonella Goldcoast reported in the United Kingdom, Poland, and China, whereas similar resistance plasmids were found in China and Cambodia. Conclusions The clinical spectrum of the high-level cephalosporin-resistant Salmonella Goldcoast is similar to that of other NTS serotypes, but severe cases required carbapenem treatment. The study confirmed the emergence of a highly antimicrobial-resistant clone of Salmonella Goldcoast, highlighting the importance of surveillance for food safety.

Whole-Genome Sequence Analysis of an Extensively Drug-Resistant Salmonella enterica Serovar Agona Isolate from an Australian Silver Gull (Chroicocephalus novaehollandiae) Reveals the Acquisition of Multidrug Resistance Plasmids

“…4; see also Table S5). Given that pSal-5364 has been experimentally demonstrated to be conjugative, it is highly probable that pSG17-135- Table S3. HI2 is also conjugative (47). Other plasmids shown in Fig.…”

Characterization and Source Investigation of Multidrug-Resistant Salmonella Anatum from a Sustained Outbreak, Taiwan

“…We collected carcass surface samples and environment samples from floor, hook, conveyor belt, meat grinder, basket, kitchen knife, chopping board and workers' hands surface in slaughterhouse, cutting factory, transport vehicle and butcher shop. Each sampling surface area of the carcass and environment samples was 100 cm 2 . In addition, each of the meat samples was collected over 25 g in cutting factory and butcher shop.…”

“…A total of 76 isolates were subjected to whole genome sequencing (WGS), that was performed using the Illumina Miseq platform (Illumina, CA, USA) and/or MinION Sequencer (Nanopore, Oxford, UK). The genome assembly and comparative analysis followed the methods as described previously (2). The genomic sequences were deposited into the GenBank database, with the accession numbers being listed in Appendix Table 1.…”

“…The NCBI Pathogen Detection Service (https://www.ncbi.nlm.nih.gov/pathogens) was searched for S. Anatum genomes that were highly similar to the genome sequences collected in Taiwan. Multilocus sequence typing was performed on all S. Anatum isolates (2,3).…”

“…as the recipient and outbreak S. Anatum isolates as the donor (Sal-4377 and Sal-4162). The conjugation assay was conducted following the protocol described in a previous study (2).…”