Detection of Multidrug-Resistant Salmonella enterica Serotype typhimurium DT104 Based on a Gene Which Confers Cross-Resistance to Florfenicol and Chloramphenicol

• DOI: 10.1128/jcm.37.5.1348-1351.1999
• Publication Date: 2019-12-31T17:44:53Z
• Authors: Lance F. Bolton; Lynda C. Kelley; Margie D. Lee; Paula J. Fedorka-...; John J. Maurer
• Keywords: Salmonella typhimurium; Thiamphenicol; 0301 basic medicine; Base Sequence; Molecular Sequence Data; Drug Resistance, Microbial; Drug Resistance, Multiple; Anti-Bacterial Agents; 3. Good health; 03 medical and health sciences; Chloramphenicol; Animals; Cattle

ABSTRACT

Salmonella enterica serotype typhimurium ( S. typhimurium ) DT104 (DT104) first emerged as a major pathogen in Europe and is characterized by its pentadrug-resistant pattern. It has also been associated with outbreaks in the United States. The organism typically carries resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline. The mechanism of chloramphenicol resistance in DT104 was determined by producing antibiotic-resistant Escherichia coli host strain clones from DT104 DNA. DNA from chloramphenicol-resistant clones was sequenced, and probes specific for the genes

flo S. typhimurium

(

flo St

), int , invA , and spvC were produced for colony blot hybridizations. One hundred nine Salmonella isolates, including 44 multidrug-resistant DT104 isolates, were tested to evaluate the specificities of the probes. The gene

flo St

, reported in this study, confers chloramphenicol and florfenicol resistance on S. typhimurium DT104. Florfenicol resistance is unique to S. typhimurium DT104 and multidrug-resistant S. typhimurium isolates with the same drug resistance profile among all isolates evaluated. Of 44 DT104 isolates tested, 98% were detected based on phenotypic florfenicol resistance and 100% had the

flo St

-positive genotype. Resistances to florfenicol and chloramphenicol are conferred by the gene

flo St

, described in this paper. Presumptive identification of S. typhimurium DT104 can be made rapidly based on the presence of the

flo St

gene or its resulting phenotype.