Does Sequence Type 33 of Shiga Toxin-Producing Escherichia coli O91 Cause Only Mild Symptoms?

Pathogenic and phylogenetic characteristics of non-O157 Shiga toxin-producingEscherichia coliisolates from retail meats in South Korea

“…DNA fingerprinting analysis provides useful information on the phylogenetic relatedness among bacterial strains. In this study, all three STEC O91:H14 isolates were identified as single-locus variants belonging to ST33; similar to that reported for STEC O91:H14 isolates from asymptomatic carriers or non-HUS patients in Japan or Germany [ 24 25 ]. Moreover, two of these isolates shared identical molecular patterns as per our PFGE results, implying that both strains are a possible clonal set with the same evolutionary origin.…”

“…In this study, however, we detected STEC O91:H14 strains among the STEC isolates from the 464 retail meats (3 STEC O91:H14 among 7 STEC isolates) and the human patients (96 STEC O91:H14 among 100 STEC isolates) in Korea. Similarly, recent studies have reported that STEC O91:H14 strains are responsible for sporadic cases of human diseases in several countries [ 24 25 ]. For example, Maeda et al [ 24 ] showed that STEC O91:H14 is one of the major non-O157 STEC O serogroups commonly isolated from asymptomatic carriers in Japan.…”

“…Similarly, recent studies have reported that STEC O91:H14 strains are responsible for sporadic cases of human diseases in several countries [ 24 25 ]. For example, Maeda et al [ 24 ] showed that STEC O91:H14 is one of the major non-O157 STEC O serogroups commonly isolated from asymptomatic carriers in Japan. In Germany, STEC O91:H14 isolates are frequently associated with asymptomatic or mild diarrheal cases without HUS [ 25 ].…”

“…Although the reasons for such low pathogenicity are unknown, our beef and pork isolates of STEC O91:H14 (i) did not thrive in an acidic environment, despite encoding AR genes such as GadA from AR2 system [ 9 ], (ii) poorly expressed Stxs, and (iii) lacked the LEE pathogenicity island. Most importantly, all the STEC O91:H14 isolates from Japan [ 24 ], German [ 25 ], and Korea were categorized into the ST33 STEC lineage.…”

Molecular epidemiology of sequence type 33 of Shiga toxin-producingEscherichia coliO91:H14 isolates from human patients and retail meats in Korea

“…Although the isolates do not belong to the big four non-O157 STEC, the same serotypes have been reported among the most common STEC isolates from diarrheal patients without HUS in Germany [11]. Moreover, it has also been reported that ST33 of STEC O91:H14 is a major causative agent of diarrhea in human patients in Japan [10].…”