title: Serotype, Shiga toxin (Stx) type, and antimicrobial resistance of Stx-producing Escherichia coli isolated from humans in Shizuoka Prefecture, Japan (2003-2007).
abstract: The serotype, Shiga toxin (Stx) type, and antimicrobial resistance patterns of  138 Stx-producing Escherichia coli (STEC) strains isolated from humans between 2003 and 2007 in  Shizuoka Prefecture, Japan were characterized. The predominant O serogroups of the STEC isolates  were O157, O26, and O111. Antimicrobial susceptibility testing of the STEC isolates showed that  31 of the 138 isolates (22.5%) were resistant to antibiotics. Compared to the results reported  in the previous studies, a higher rate of STEC O157 isolates were susceptible to all the  antimicrobial agents used in this study. However, antimicrobial susceptibility data from this  study showed that antimicrobial resistance patterns have increased by 6 compared to the survey  performed by Masuda et al. between 1987 and 2002 (Jpn. J. Food Microbiol., 21, 44-51, 2004).  This indicates that STEC isolates have evolved to show a variety of antimicrobial resistance  patterns. It is important to consider the population of isolates showing decreased  susceptibility to clinically relevant drugs such as ciprofloxacin (CPFX) and fosfomycin (FOM).  All the 3 STEC isolates resistant to nalidixic acid showed low susceptibility to CPFX (MIC,  0.25-0.5 μg/ml). In addition, a decreased susceptibility to FOM was clearly observed in the  E. coli O26 isolates. Our findings also showed that 1 STEC O26 strain could possibly be a  chromosomal AmpC β-lactamase hyperproducer. These results suggest that antimicrobial therapy  may be less effective in patients with non-O157 STEC infections than in those with STEC O157  infections.
authors.affiliation: Department of Microbiology, Shizuoka Institute of Environment and Hygiene, Shizuoka 420-8637, Japan. midori1_hiroi＠pref.shizuoka.lg.jp
authors.forename: Midori
authors.initials: M
authors.lastname: Hiroi
authors.forename: Naomi
authors.initials: N
authors.lastname: Takahashi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Harada
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Kawamori
authors.forename: Natsuko
authors.initials: N
authors.lastname: Iida
authors.forename: Takashi
authors.initials: T
authors.lastname: Kanda
authors.forename: Kanji
authors.initials: K
authors.lastname: Sugiyama
authors.forename: Norio
authors.initials: N
authors.lastname: Ohashi
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Hara-Kudo
authors.forename: Takashi
authors.initials: T
authors.lastname: Masuda
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004196:Disease Outbreaks; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D005578:Fosfomycin / Q000494:pharmacology; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D012703:Serotyping; D022603:Shiga Toxins / Q000096:biosynthesis / Q000145:classification* / Q000235:genetics*; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D014774:Virulence; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D022603:Shiga Toxins; D005578:Fosfomycin; C048795:AmpC beta-lactamases; D001618:beta-Lactamases