title: Detection of multidrug-resistant Salmonella enterica serovar typhimurium phage types DT102, DT104, and U302 by multiplex PCR.
abstract: Salmonella enterica serovar Typhimurium is a common cause of nontyphoidal salmonellosis in humans and animals. Multidrug-resistant serovar Typhimurium phage type DT104, which emerged in the 1990s, has become widely distributed in many countries. A total of 104 clinical isolates of Salmonella serogroup B were collected from three major hospitals in Taiwan during 1997 to 2003 and were examined by a multiplex PCR targeting the resistance genes and the spv gene of the virulence plasmid. A total of 51 isolates (49%) were resistant to all drugs (ACSSuT [resistance to ampicillin, chloramphenicol, streptomycin, sulfonamide, and tetracycline]), and all contained a 1.25-kb PCR fragment of integron that is part of the 43-kb Salmonella genomic island 1 (SGI1). The second group was resistant to SSu (28%), and the third was susceptible to all five drugs (13%). Fifty-nine isolates were serotyped to be serovar Typhimurium by the tube agglutination method using H antisera. The virulence plasmid was found in 54 (91.5%) of the 59 serovar Typhimurium isolates. A majority (94.1%) of the Salmonella serogroup B isolates with the ACSSuT resistance pattern harbored a virulence plasmid. Phage typing identified three major phage types: DT104, DT120, and U302. Analysis of the isolates by pulsed-field gel electrophoresis showed six genotypes. We found two genotypes in DT104 strains, two in DT120, and the other two in U302. The presence of a monophasic serovar (4,5,12:i:-) has added difficulty in the determination of the serovars of multidrug-resistant Salmonella serogroup B isolates. Nevertheless, the multiplex PCR devised in the present study appears to be efficient and useful in the rapid identification of ACSSuT-type serovar Typhimurium with SGI1, irrespective of their phage types.
authors.affiliation: Department of Pediatrics, Chang Gung Children's Hospital, and Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Cheng-Hsun
authors.initials: CH
authors.lastname: Chiu
authors.forename: Lin-Hui
authors.initials: LH
authors.lastname: Su
authors.forename: Chi-Hong
authors.initials: CH
authors.lastname: Chu
authors.forename: Mei-Hwei
authors.initials: MH
authors.lastname: Wang
authors.forename: Chia-Ming
authors.initials: CM
authors.lastname: Yeh
authors.forename: Francois-Xavier
authors.initials: FX
authors.lastname: Weill
authors.forename: Chishih
authors.initials: C
authors.lastname: Chu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D001434:Bacteriophage Typing; D002876:Chromosomes, Bacterial / Q000235:genetics; D016172:DNA Fingerprinting; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D044404:Genomic Islands; D005838:Genotype; D006761:Hospitals; D006801:Humans; D032023:Integrons; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods*; D012480:Salmonella Infections / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000145:classification* / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D012703:Serotyping; D013624:Taiwan; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins