Detection of multidrug-resistant Salmonella typhimurium DT104 by multiplex polymerase chain reaction.
Salmonella typhimurium definitive type 104 (DT104) is a virulent pathogen for humans and animals with many strains having multiple drug resistance characteristics. The organism typically carries resistance to ampicillin, chloramphenicol, florfenicol, streptomycin, sulfonamides, and tetracycline (ACSSuT-resistant). A multiplex PCR method was developed to simultaneously amplify four genes, florfenicol (flo(st)), virulence (spvC), invasion (invA), and integron (int) from S. typhimurium DT104 (ACSSuT-type). Twenty-two ACSSuT-resistant DT104 isolates in our collection gave 100% positive reactions to this PCR assay by amplifying 584-, 392-, 321- and 265-bp PCR products, using primers specific to the respective target genes. One Salmonella strain DT23, ACSSuT-resistant, phage type 711 failed to amplify the 584-bp fragment, indicating that this method is specific for DT104-type ACSSuT-resistant S. typhimurium strains. One clinical and one bovine ASSuT-resistant strains that were sensitive to chloramphenicol and florfenicol did not yield a 584-bp fragment, indicating the absence of the flo(st) gene. This method will be useful for rapid identification of ACSSuT-type DT104 strains from clinical, food and environmental samples.
Khan
A A
AA
Division of Microbiology, Food and Drug Administration, National Center for Toxicological Research, Jefferson, AR 72079, USA. akhan@nctr.fda.gov
Nawaz
M S
MS
Khan
S A
SA
Cerniglia
C E
CE
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001431:Bacteriological Techniques; D002417:Cattle; D017931:DNA Primers; D004352:Drug Resistance, Microbial / Q000235:genetics; D018432:Drug Resistance, Multiple / Q000235:genetics; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D012480:Salmonella Infections / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D013045:Species Specificity
D000900:Anti-Bacterial Agents; D017931:DNA Primers