title: The usefulness of semi-solid medium in the isolation of highly virulent Leptospira strains from wild rats in an urban area of Fukuoka, Japan.
abstract: Leptospirosis is a worldwide zoonosis. The importance of urban leptospirosis is recognized in Japan: urban rats carry pathogenic leptospires and people acquire these pathogens through contact with surface water or soil contaminated by the urine of the infected animals. To determine the current Leptospira carriage rate in urban rats, 29 wild rats were trapped in the central area of Fukuoka and strains isolated from their kidneys and urine analyzed. When semi-solid Korthof's medium containing 0.1% agar was used for isolation, 72.2% and 30.8% of the kidney and urine cultures, respectively, were found to be Leptospira-positive. The isolates belonged to Leptospira interrogans, and were classified into two groups (serogroups Pomona and Icterohaemorrhagiae) based on the results of gyrB sequence analysis and microscopic agglutination testing (MAT). Strains belonging to serogroup Icterohemorrhagiae grew well in liquid medium. On the other hand, serogroup Pomona isolates multiplied very little in liquid medium, but did grow in a semi-solid medium. Although strains belonging to serogroup Pomona have not been recognized as native to Japan, this strain may be widely distributed in urban rats. Representative strains from each group were found to be highly pathogenic to hamsters. Our findings should serve as a warning that it is still possible to become infected with leptospires from wild rats living in inner cities of Japan. Furthermore, the use of semi-solid medium for culture will improve the isolation rate of leptospires from the kidneys of wild rats.
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Saito
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Sharon Y A M
authors.initials: SY
authors.lastname: Villanueva
authors.affiliation: Laboratory of Microbiology and Immunology, Faculty of Pharmaceutical Sciences, Chiba Institute of Science, Choshi, Chiba, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Masuzawa
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Haraguchi
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Ita
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Miyahara
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Ozuru
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Michinobu
authors.initials: M
authors.lastname: Yoshimura
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Ikejiri
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Natsumi
authors.initials: N
authors.lastname: Aramaki
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Muhammad Yunus
authors.initials: MY
authors.lastname: Amran
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Lisa Tenriesa
authors.initials: LT
authors.lastname: Muslich
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Ken-ichiro
authors.initials: K
authors.lastname: Iida
authors.affiliation: Laboratory of Microbiology and Immunology, Faculty of Pharmaceutical Sciences, Chiba Institute of Science, Choshi, Chiba, Japan.|Department of Medical Microbiology, College of Public Health, University of the Philippines-Manila, Ermita, Manila, Philippines.|University of Shizuoka, Shizuoka, Japan.
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Yanagihara
authors.affiliation: Department of Medical Microbiology, College of Public Health, University of the Philippines-Manila, Ermita, Manila, Philippines.
authors.forename: Nina G
authors.initials: NG
authors.lastname: Gloriani
authors.affiliation: Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Yoshida
mesh_terms: D000372:Agglutination Tests; D000818:Animals; D001431:Bacteriological Techniques / Q000379:methods*; D002947:Cities; D003470:Culture Media / Q000737:chemistry*; D027081:DNA Gyrase / Q000235:genetics; D004195:Disease Models, Animal; D007564:Japan; D007668:Kidney / Q000382:microbiology; D007921:Leptospira interrogans / Q000302:isolation & purification* / Q000472:pathogenicity; D007922:Leptospirosis / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D008647:Mesocricetus; D051381:Rats; D012376:Rodent Diseases / Q000175:diagnosis* / Q000382:microbiology*; D014556:Urine; D014774:Virulence
chemical_list: D003470:Culture Media; D027081:DNA Gyrase
keywords: Leptospira interrogans; semi-solid Korthof's mediom; serogroup Pomona; wild rat