A Molecular Epidemiological Analysis of the First Toxin-Producing Shigella dysentery Type 1 Strain Isolated in Taiwan
2003 Vol.19 NO.1
It was the first Shigella dysentery type 1 case detected in Taiwan. The case was a Japanese male visitor who entered Taiwan on 26 November, and was admitted to hospital for abdominal pain, diarrhea, fever and bloody stool. The case was reported and specimen sent to the Center for Disease Control of the Department of Health (CDC) as suspected typhoid case. By isolation, the CDC confirmed the case as Shigella dysentery type 1 infection (coded TA-1). Preventive measures were immediately taken. Conditions of the case are stable and no further infections have been reported. By PCR and RPLA, the strain was proved to be shiga-toxin-producing. Further comparison with the same serotype strain preserved by Japan in 1966 (coded #450) found that though both of them carried shiga-toxins, they were significantly different in drug-resistance graph and pulsed field gel electrophoresis graph patterns. It was speculated that the two strains were not molecularly related. A further analysis of the gene sequences of the shiga-like toxin (SLT) and the Gyrase A of TA-1 and #450 strains showed that the SLT gene sequences (475bp) of both strains were the same; whereas the Gyrase A gene sequences (648bp) of TA-1 showed point mutation at 185 and 197, from ser185 (TCG)→lys (TTG), and Asp197(GAC)→Gly (GGC). This was due to the gene mutation of resistance to ciprofloxacin.