Molecular Epidemiology of Salmonella Genomic Island 1 (SGI1) in Various Salmonella Serovars

• Main Authors: Yi-Ling Shiau, 蕭依玲
• Other Authors: Chao-Chin Chang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/75gs5q

碩士 === 國立中興大學 === 微生物暨公共衛生學研究所 === 101 === Multidrug resistance (MDR) in Salmonella has become a global public health issue. Salmonella genomic island 1 (SGI1) was initially described in the epidemic Salmonella Typhimurium phage type DT104 strain and contains a MDR region with resistance of ampicillin (A), chloramphenicol (C), streptomycin (S), sulfonamide (Su) and tetracycline (T). Variants of SGI1 from SGI1-A to SGI1-V have been described in different Salmonella serovars and Proteus mirabilis. The objective of this study was to develop a quick molecular method to identify SGI1 variants in 463 Salmonella isolates including 9 serovars in Taiwan. The results indicated that 22.9% of Salmonella isolates carrying SGI1, and prevalence of SGI1 positivity in human isolates were significantly higher than that in animal isolates (36.7% vs. 13.5%; p<0.05). Different SGI1 variants were identified in various Salmonella serovars: SGI1 in S. Typhimurium, SGI1-J3 in S. Choleraesuis, SGI1-B and SGI1-F in S. Albany, SGI1-F and SGI1-I in S. Newport and SGI1-F in S. Bredeney. None of the S. Enteritidis, Heron, Treforest and Salmonella serovar 4,[5],12:i:- were SGI1-positive. However, MDR of ACSSuT could still be observed in S. Enteritidis. It was also found that the isolate with the specific SGI1 variant did not always show a unique MDR phenotype. To the best of our knowledge, this is the first study to identify SGI1-J3 in S. Choleraesuis and SGI1-F in S. Bredeney. Furthermore, in S. Choleraesuis, we identified one novel SGI1 variant showing CSSuT resistance. This variant is closest to SGI1-J6 but with the gene cassette of intI1- sat- psp- aadA2- qacEΔ1- sul1 in the first fragment of class I integron and without insertion of ISSen5 within ORF S023 in SGI1 backbone.