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ABSTRACTVibrio choleraeO1 classical (CL) biotype caused the fifth and sixth pandemics, and probably the earlier cholera pandemics, before the El Tor (ET) biotype initiated the seventh pandemic in Asia in the 1970s by completely displacing the CL biotype. Although the CL biotype was thought to be extinct in Asia and although it had never been reported from Latin America, V. choleraeCL and ET biotypes, including a hybrid ET, were found associated with areas of cholera endemicity in Mexico between 1991 and 1997. In this study, CL biotype strains isolated from areas of cholera endemicity in Mexico between 1983 and 1997 were characterized in terms of major phenotypic and genetic traits and compared with CL biotype strains isolated in Bangladesh between 1962 and 1989. According to sero- and biotyping data, all V. choleraestrains tested had the major phenotypic and genotypic characteristics specific for the CL biotype. Antibiograms revealed the majority of the Bangladeshi strains to be resistant to trimethoprim-sulfamethoxazole, furazolidone, ampicillin, and gentamicin, while the Mexican strains were sensitive to all of these drugs, as well as to ciprofloxacin, erythromycin, and tetracycline. Pulsed-field gel electrophoresis (PFGE) of NotI-digested genomic DNA revealed characteristic banding patterns for all of the CL biotype strains although the Mexican strains differed from the Bangladeshi strains in 1 to 2 DNA bands. The difference was subtle but consistent, as confirmed by the subclustering patterns in the PFGE-based dendrogram, and can serve as a regional signature, suggesting the pre-1991 existence and evolution of the CL biotype strains in the Americas, independent from Asia.

ABSTRACTMultilocus sequence typing of Borrelia gariniiisolates from humans and comparison with rodent and tick isolates were performed. Fifty-nine isolates were divided into two phylogenetic groups, and an association was detected between clinical and rodent isolates, suggesting that, in Japan, human-pathogenic B. gariniicomes from rodents via ticks.

ABSTRACTEnterohemorrhagic Escherichia coliO157 (EHEC O157) is a food-borne pathogen that has raised worldwide public health concern. The development of simple and rapid strain-typing methods is crucial for the rapid detection and surveillance of EHEC O157 outbreaks. In the present study, we developed a multiplex PCR-based strain-typing method for EHEC O157, which is based on the variability in genomic location of IS629among EHEC O157 strains. This method is very simple, in that the procedures are completed within 2 h, the analysis can be performed without the need for special equipment or techniques (requiring only conventional PCR and agarose gel electrophoresis systems), the results can easily be transformed into digital data, and the genes for the major virulence markers of EHEC O157 (the stx1, stx2, and eaegenes) can be detected simultaneously. Using this method, 201 EHEC O157 strains showing different XbaI digestion patterns in pulsed-field gel electrophoresis (PFGE) analysis were classified into 127 types, and outbreak-related strains showed identical or highly similar banding patterns. Although this method is less discriminatory than PFGE, it may be useful as a primary screening tool for EHEC O157 outbreaks.

ABSTRACTThirteen Streptococcus dysgalactiaesubsp. equisimilisisolates possessing Lancefield's group A antigen recovered from people in Japan during 2000 to 2004 were genotyped. The results indicate that a conserved clone has persisted and spread within Japan, and two different emmtypes were observed within members of this clone.

ABSTRACTStrains of the multidrug-resistant (MDR) Salmonella entericaserovar Typhimurium isolated in Japan were examined for high-level fluoroquinolone resistance. Since the first isolation in 2000 (described in reference 13), we have identified 12 human and 5 nonhuman isolates with high-level fluoroquinolone-resistance (ciprofloxacin MIC of 24 µg/ml or more). Most of these isolates shared some features including definitive phage type (DT12/193), resistance type (ACSSuTNCp; resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, tetracycline, nalidixic acid, and ciprofloxacin), and genotype on pulsed-field gel electrophoresis that were different from those of the MDR S. entericaTyphimurium DT104. Mutations in quinolone resistance-determining regions of gyrAand parCwere also conserved in almost all of the isolates despite the absence of any apparent epidemiological relationships among cases. This suggests that a specific clonal group of the serovar Typhimurium with high levels of fluoroquinolone resistance is disseminating among animals and humans in Japan.

ABSTRACTA genomic subtraction between a pandemic Vibrio parahaemolyticusand a nonpandemic strain that seemed to be clonally related was performed. A subtractive DNA fragment was identified to be a part of a 16-kbp insertion sequence which was present in almost all pandemic strains but not in nonpandemic strains tested.

ABSTRACTA total of 54 Vibrio parahaemolyticusstrains including pandemic O3:K6 strains and newly emerged O4:K68, O1:K25, O1:K26, and O1:K untypeable strains (collectively referred to as the “pandemic group”) were examined for their pulsed-field gel electrophoresis (PFGE) and arbitrarily primed PCR (AP-PCR) profiles and for the presence or absence of genetic marker DNA sequences, toxRS/newor orf8, that had been reported elsewhere to be specific for the pandemic group. Both PFGE and AP-PCR analyses indicated that all strains of the pandemic group formed a distinct genotypic cluster, suggesting that they originated from the same clone. In addition to the pandemic group, four O3:K6 strains that did not possess the thermostable direct hemolysin (tdh) gene also belonged to this cluster and possessed the toxRS/newsequence. However, three O3:K6 strains that clearly belonged to the pandemic group by PFGE and AP-PCR did not possess the orf8sequence. The evidence suggests that neither the toxRS/newnor the orf8sequence is a reliable gene marker for definite identification of the pandemic group. We therefore developed a novel multiplex PCR assay specific for the pandemic group. The assay successfully distinguished pandemic group strains from other V. parahaemolyticusstrains by yielding two distinct PCR products for tdh(263 bp) and the toxRS/newsequence (651 bp).

ABSTRACTThe PCR primers for O, H, and Vi antigen genes, tyv(rfbE), prt(rfbS), fliC-d, fliC-a, and viaB, were designed and used for the rapid identification of Salmonella entericaserovars Typhi and Paratyphi A with multiplex PCR. The results showed that all the clinical isolates examined of Salmonellaserovars Typhi and Paratyphi A were accurately identified by this assay.

ABSTRACTA total of 221 isolates of multidrug-resistant Salmonella entericaserovar Typhimurium in Japan were characterized in the present study. The results revealed that clonal serovar Typhimurium definitive phage type 104 strains prevailed and that these strains had drug resistance patterns, integron types, and pulsed-field gel electrophoresis patterns similar to those predominant among isolates in Western countries.

ABSTRACTTo determine the phage types (PT) of Salmonella enteritidisfound in Thailand and to clarify the potential for human infection by S. enteritidisin broiler chicken meat, human and poultry isolates taken from Thailand between 1990 and 1997 were phage typed and analyzed by pulsed-field gel electrophoresis (PFGE). Ten different PT were found among the 302 isolates phage typed, with PT 4 being the most frequent in human (73.9%) and poultry (76.2%) isolates, followed by PT 1 (8.0%), 8 (3.6%), and 7a (2.2%) in human isolates and by PT 7a (4.9%), 1 (3.7%), and 12 (2.4%) in poultry isolates. Of the 53 isolates analyzed by PFGE, 45 showed an indistinguishable pattern (pattern A) byBlnI-digested PFGE and the other 8 isolates showed a very similar pattern that differed by only a few bands. These results indicate the spread of a genetically identical clone ofS. enteritidisin humans and poultry in Thailand.

ABSTRACTWe report the first case of neonatal Legionnaires' disease associated with water birth in a spa bath at home. Legionella pneumophilaserogroup 6 was detected from postmortem lung tissue.

ABSTRACTThree clinical strains of enterohemorrhagic Escherichia coliO157:H7 which were subcultured repeatedly or stored at room temperature over a 25-week period showed appreciable variations in their pulsed-field gel electrophoresis fragment patterns. The variations could be explained by a couple of spontaneous genetic events at most and thus did not invalidate the genetic lineage of the strains.

ABSTRACT?-Glutamyl aminopeptidase (GGT) activity is used as a specific marker for the identification of Neisseria meningitidis. We isolated from a healthy carrier and characterized an N. meningitidisisolate which lacked the activity due to the insertional mutation of the ggtgene, suggesting that naturally occurring N. meningitidisisolates do not always possess GGT activity.

ABSTRACTSixty-seven Vibrio choleraeO1 El Tor isolates (36 domestic and 31 imported) were classified into 19 subtypes byNotI- and SfiI-digested pulsed-field gel electrophoresis. Twenty-five of 36 domestic and 4 imported isolates were assigned to a NotI-A1–SfiI-A1 subtype, suggesting that this pulse type is widely distributed in Asia and Japan.